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This study aimed to establish a blood vessel model within a hollow fiber bioreactor to evaluate the impact of high and fluctuating glucose levels on human umbilical vein endothelial cells (HUVECs) under laminar shear stress (LSS). HUVECs were cultured for 48 h in normal (5 mM), high (20 mM), and variable (20 mM / 5 mM alternating every 24 h) glucose concentrations under LSS of 0.66 Pa. An automated medium replacement system was developed. The control cultures remained static. The analysis included cell viability via cytometric analysis, glucose consumption, lactate production via electroenzymatic methods, and the expression of 21 genes via qPCR. The percentage of apoptotic cells did not significantly differ across glucose concentrations under LSS. HUVECs favor glycolysis for energy regardless of LSS. Under LSS, the IL1B , CCL2 , and SELE genes were upregulated under high-glucose conditions and downregulated under variable-glucose conditions. A few other genes related to inflammation, oxidative stress, cell adhesion and apoptosis were upregulated under high-glucose conditions. In conclusion, using the blood vessel model we effectively examined the impact of glucose profiles on HUVECs under LSS in a device replicating the cylindrical geometry of blood vessels. LSS and tubular cell arrangement might mitigate the adverse effects of variable glucose on endothelial cells. [ABSTRACT FROM AUTHOR]

The role of hydrogen sulfide and its releasing agents in diabetic wound healing. [Display omitted] • This mini-review briefly introduces the causes of diabetic wound healing and the direction of clinical treatment. • This mini-review provides reasons why hydrogen sulfide may be considered for the treatment of diabetic wound healing. • This mini-review discusses the role of hydrogen sulfide in various stages of diabetic wound healing. • This mini-review involves ideas to improve hydrogen sulfide availability to aid future developments. • The mini-review suggests that hydrogen sulfide is a new hope for improving diabetic wound healing. Diabetes mellitus (DM) is a long-term metabolic disease accompanied by difficulties in wound healing placing a severe financial and physical burden on patients. As one of the important signal transduction molecules, both endogenous and exogenous hydrogen sulfide (H 2 S) was found to promote diabetic wound healing in recent studies. H 2 S at physiological concentrations can not only promote cell migration and adhesion functions, but also resist inflammation, oxidative stress and inappropriate remodeling of the extracellular matrix. The purpose of this review is to summarize current research on the function of H 2 S in diabetic wound healing at all stages, and propose future directions. In this review, first, the various factors affecting wound healing under diabetic pathological conditions and the in vivo H 2 S generation pathway are briefly introduced. Second, how H 2 S may improve diabetic wound healing is categorized and described. Finally, we discuss the relevant H 2 S donors and new dosage forms, analyze and reveal the characteristics of many typical H 2 S donors, which may provide new ideas for the development of H 2 S-released agents to improve diabetic wound healing. [ABSTRACT FROM AUTHOR]

High glucose (HG)-induced aberrant proliferation, apoptosis and odontoblastic differentiation of dental pulp cells (DPCs) have been implicated in the pathogenesis of impaired diabetic pulp healing; however, the underlying mechanism remains unclear. This study aimed to investigate the role of mitochondrial reactive oxygen species (mtROS) and mitochondria in HG-induced dysfunction and apoptosis of DPCs. Human DPCs (hDPCs) were cultured in a low-glucose, high-glucose, mannitol, and MitoTEMPO medium in vitro. Methylthiazol tetrazolium assay, Annexin V-FITC/PI staining and scratch-wound assay were used to analyze cell proliferation, apoptosis and migration, respectively. Alkaline phosphatase staining and alizarin red S staining were used to evaluate cell differentiation. DCF-DA staining, MitoSOX staining, MitoTracker Red staining, JC-1 staining, and adenosine triphosphate (ATP) kit assay were performed to investigate total ROS and mtROS generation, mitochondrial density, mitochondrial membrane potential (MMP), and ATP synthesis, respectively. Quantitative PCR assay was performed to detect the mRNA expression of mitochondrial biogenesis- and dynamics-related markers. Transmission electron microscopy was used to observe the mitochondrial ultrastructure. HG augmented the production of total ROS and mtROS, and triggered mitochondrial damage in hDPCs, as reflected by decreased mitochondrial density, depolarized MMP, reduced ATP synthesis, altered mRNA expression of mitochondrial biogenesis- and dynamics-related markers, and abnormal mitochondrial ultrastructure. Supplementation of MitoTEMPO alleviated the mitochondrial damage and reversed the aberrant proliferation, apoptosis, migration and odontoblastic differentiation of HG-stimulated hDPCs. HG triggers mitochondrial damage via augmenting mtROS generation, resulting in the inhibited proliferation, migration, and odontoblastic differentiation of hDPCs and enhanced their apoptosis. [ABSTRACT FROM AUTHOR]

/purpose: Periodontal disease is a chronic inflammatory disease that occurs in the tissues that support and attach teeth. There is considerable evidence of a relationship between diabetes and periodontal disease. Emerging studies have reported that myeloid-derived growth factor (MYDGF) can inhibit apoptosis and inflammation. The purpose of this study was to investigate whether MYDGF mediates the role of hyperglycemia in fibroblasts in periodontitis tissues. Fibroblasts were isolated and cultured from normal gums. Gene expression levels were detected by RT-PCR. The protein level was detected by western blotting. Cell viability was determined by MTT assay. To investigate the role of MYDGF, the plasmid was transfected into fibroblasts. The expression levels of cytokines were determined by ELISA. High glucose can down-regulate the expression of MYDGF in human gingival fibroblasts in a time-dependent manner, and decrease the fibroblast activity. SOD level was decreased and MDA level was increased in gingival fibroblasts by high glucose. High glucose up-regulates pro-apoptotic indicator Bax, down-regulates anti-apototic indicator Bcl-2, and increased endoplasmic reticulum stress related indicators Nox 2, GRP78, ATF6, and PERK. In addition, high glucose increased TNF-α, IL-1β, IL-8 and CXCL1 protein levels in fibroblasts. Our study also found that high glucose inhibits the AKT signaling pathway and activates the nuclear factor κB (NF-κB) pathway. Interestingly, overexpression of MYDGF reversed these effects. MYDGF is down-regulated in gingival fibroblasts induced by high glucose. Overexpression of MYDGF inhibits apoptosis induced by high glucose, inhibits oxidative stress and cytokine secretion of gingival fibroblasts induced by high glucose, and induces AKT pathway activation and NF-κB pathway inhibition. [ABSTRACT FROM AUTHOR]

Impaired wound healing is a serious diabetes complication compromising patients' quality of life. However, the pathogenesis of diabetic wounds (DWs) remains incompletely understood. Human epidermal keratinocyte (HEK) is the sentinel cell that initiates healing processes after the epidermal integrity has been disrupted. This study aimed to investigate the functional roles of HEKs in wound healing and to identify candidate genes, signaling pathways and molecular signatures contributing to the DWs. HEKs were cultured in normal or high-glucose environment, followed by scratch, to mimic the microenvironment of normal wounds and DWs. Subsequently, we performed RNA sequencing and systematically analyzed the expression profiles by bioinformatics approaches. High-glucose environment altered the keratinocyte transcriptome responses to wounding. In experimental model of DWs, we found that TNF, CYP24A1, NR4A3 and GGT1 were key overexpressed genes in keratinocytes and were implicated in multiple cellular responses. Further analysis showed that wounding in high-glucose environment activated G-protein-coupled receptor (GPCR) signaling, cAMP response element-binding protein (CREB) signaling, and adrenomedullin signaling in keratinocytes, while dysregulated skin development and immune responses as compared to their counterpart in normal glucose settings. This simplified in-vitro model serves as a valuable tool to gain insights into the molecular basis of DWs and to facilitate establishment of personalized therapies in clinical practice • High-glucose environment altered the keratinocyte transcriptome responses to wounding. • In high-glucose cultivated keratinocytes, TNF, CYP24A1, NR4A3 and GGT1 were key overexpressed genes after wounding. • In high-glucose environment, wounding suppressed keratinocyte differentiation, while promoted myeloid leukocyte activation. • Keratinocytes from different individuals demonstrated diverse cellular responses to wounding in high-glucose environment. • The model is a valuable tool to explore the heterogeneity in the pathomechanism of diabetic wounds among individuals. [ABSTRACT FROM AUTHOR]

[Display omitted] Mitochondrial dysfunction is associated with hyperglycemic conditions and insulin resistance leading to cellular damage and apoptosis of cardiomyocytes in diabetic cardiomyopathy. The dysregulation of glucagon-like peptide-1 (GLP-1) receptor and mammalian target of rapamycin (mTOR) is linked to cardiomyopathies and myocardial dysfunctions mediated by hyperglycemia. However, the involvements of mTOR for GLP-1 receptor-mediated cardioprotection against high glucose (HG)-induced mitochondrial disturbances are not clearly identified. The present study demonstrated that HG-induced cellular stress and mitochondrial damage resulted in impaired ATP production and oxidative defense markers such as catalase and SOD2, along with a reduction in survival markers such as Bcl-2 and p-Akt, while an increased expression of pro-apoptotic marker Bax was observed in H9c2 cardiomyoblasts. In addition, the autophagic marker LC3-II was considerably reduced, together with the disruption of autophagy regulators (p-mTOR and p-AMPKα) under the hyperglycemic state. Furthermore, there was a dysregulated expression of several indicators related to mitochondrial homeostasis, including MFN2, p-DRP1, FIS1, MCU, UCP3, and Parkin. Remarkably, treatment with either exendin-4 (GLP-1 receptor agonist) or rapamycin (mTOR inhibitor) significantly inhibited HG-induced mitochondrial damage while co-treatment of exendin-4 and rapamycin completely reversed all mitochondrial abnormalities. Antagonism of GLP-1 receptors using exendin-(9–39) abolished these cardioprotective effects of exendin-4 and rapamycin under HG conditions. In addition, exendin-4 attenuated HG-induced phosphorylation of mTOR, and this inhibitory effect was antagonized by exendin-(9–39), indicating the regulation of mTOR by GLP-1 receptor. Therefore, improvement of mitochondrial dysfunction by stimulating the GLP-1 receptor/AMPK/Akt pathway and inhibiting mTOR signaling could ameliorate cardiac abnormalities caused by hyperglycemic conditions. [ABSTRACT FROM AUTHOR]

Cordyceps sinensis is widely known for its therapeutic properties. Enhancing the yield of exopolysaccharides (EPS), which is crucial for its medicinal efficacy, is a major challenge. In this study, we applied high initial glucose concentrations with talc particles to enhance EPS production and assessed the cell morphology, intracellular biochemical reactants, and bioactivity contribution of glycoproteins. The use of 150 g/L glucose and 10 g/L 2000 mesh talc increased the EPS yield by 1.8-fold to 4.21 g/L. The addition of talc regulated cell morphology, facilitated the entry of oxygen molecules into the cells to produce a large amount of ATP for polysaccharide synthesis, and altered the cell wall structure to facilitate the secretion of EPS. Moreover, environmental stress resulted in a notable increase in intracellular reactive oxygen species levels, which can potentially enhance cell membrane permeability and promote EPS synthesis. Furthermore, the highest protein content in crude EPS corresponded to the maximum activation of alcohol dehydrogenase (ADH) of 44.2 %, suggesting a mechanistic relationship between the proteins and polysaccharides in the glycoproteins that influence the activation of ADH. These findings elucidate the intricate interplay between fermentation conditions and EPS production and provide new avenues for optimizing the fermentation process of CS-HKI to enhance its therapeutic applications. [Display omitted] • High yield exopolysaccharides (EPS) were achieved by Cordyceps CS-HK1 fermentation. • High glucose and talc could increase the yield of EPS by 1.8 times to 4.21 g/L. • Changes of cell morphology, wall structure and membrane permeability were observed. • Intracellular reactive oxygen species, antioxidant enzymes and ATP were changed. • Proteins were important components in EPS positively related to ADH activation. [ABSTRACT FROM AUTHOR]

In this study, we have investigated the effect of Astragaloside IV on keratinocytes' proliferation, migration, oxidative stress, apoptosis, inflammation, and relevant signaling pathway, using human keratinocytes exposed to high glucose. Astragaloside IV is one of the main active ingredients of Astragalus membranaceus (Fisch.) Bunge. Previous studies have found that Astragaloside IV exerts positive effects in various disease models and promotes wound healing. Cell proliferation and migration of keratinocytes, oxidative stress indicators, cell apoptosis rate, inflammatory factors, and key proteins in the TGF-β/Smad signaling pathway were evaluated by molecular biology/biochemical techniques, fluorescence microscope, and flow cytometry. High glucose inhibited the cell proliferation and migration of keratinocytes, upregulated the levels of MDA, ROS, IL-6, IL-8, and Smad7, and decreased the levels of SOD, IL-10, TGF-β1, p-Smad2, and p-Smad3. Astragaloside IV attenuated the dysfunction of keratinocytes, oxidative stress, cell apoptosis, and inflammation, but activated TGF-β/Smad signaling pathway. Meanwhile, the addition of SB431542 (the inhibitor of TGF-β/Smad signaling pathway) eliminated the impact of Astragaloside IV on high glucose-induced keratinocytes. These results strongly suggest that Astragaloside IV may be a potential drug candidate for accelerating diabetic wound healing, by protecting keratinocytes against damages induced by high glucose and TGF-β/Smad pathway is involved in this process at the cellular level. • High glucose induces dysfunction of keratinocytes. • Astragaloside IV could protect keratinocytes via TGF-β/Smad pathway. ⋅ • Astragaloside IV may be a potential drug candidate for accelerating diabetic wound healing. [ABSTRACT FROM AUTHOR]

High glucose (HG) can influence the osteogenic differentiation ability of periodontal ligament stem cells (PDLSCs). Human umbilical cord mesenchymal stem cell-derived exosomes (hUCMSC-exo) have broad application prospects in tissue healing. The current study aimed to explore whether hUCMSC-exo could promote the osteogenic differentiation of hPDLSCs under HG conditions and the underlying mechanism. We used a 30 mmol/L glucose concentration to simulate HG conditions. CCK-8 assay was performed to evaluate the effect of hUCMSC-exo on the proliferation of hPDLSCs. Alkaline phosphatase (ALP) staining, ALP activity, and qRT-PCR were performed to evaluate the pro-osteogenic effect of hUCMSC-exo on hPDLSCs. Western blot analysis was conducted to evaluate the underlying mechanism. The results of the CCK-8 assay, ALP staining, ALP activity, and qRT-PCR assay showed that hUCMSC-exo significantly promoted cell proliferation and osteogenic differentiation in a dose-dependent manner. The Western blot results revealed that hUCMSC-exo significantly increased the levels of p-PI3K and p-AKT in cells, and the effect was inhibited by LY294002 (PI3K inhibitor) or MK2206 (AKT inhibitor), respectively. Moreover, the increases in osteogenic indicators induced by hUCMSC-exo were significantly suppressed by LY294002 and MK2206. hUCMSC-exo promote the osteogenic differentiation of hPDLSCs under HG conditions through the PI3K/AKT signaling pathway. [ABSTRACT FROM AUTHOR]

Mathurameha is a traditional Thai herbal formula with a clinically proven effect of blood sugar reduction in patients with diabetes mellitus, but its anti-diabetic complication potential is largely unknown. This study aimed to elucidate the effects of Mathurameha and its underlying mechanisms against high glucose-induced endothelial dysfunction in human endothelial EA.hy926 cells. After confirming no cytotoxic effects, the cells were treated with normal glucose (NG), high glucose (HG), or high glucose plus Mathurameha (HG + M) for 24 h. A quantitative label-free proteomic analysis using the sequential window acquisition of all theoretical mass spectra (SWATH-MS) approach identified 24 differentially altered proteins among the three groups: 7 between HG and NG, 9 between HG + M and NG, and 13 between HG + M and HG. Bioinformatic analyses suggested a potential anti-diabetic action through the epidermal growth factor (EGF) pathway. Subsequent functional validations demonstrated that Mathurameha reduced the EGF secretion and the intracellular reactive oxygen species (ROS) level in high glucose-treated cells. Mathurameha also exhibited a stimulatory effect on nitric oxide (NO) production while significantly reducing the secretion of endothelin-1 (ET-1) and interleukin-1β (IL-1β) in high glucose-treated cells. In conclusion, our findings demonstrated that Mathurameha attenuated high glucose-induced endothelial dysfunction through the EGF/NO/IL-1β regulatory axis. This study reveals the potential of Mathurameha, a traditional Thai herbal formula, in mitigating high glucose-induced endothelial dysfunction, a common complication in diabetes mellitus. Using proteomics and bioinformatic analyses followed by functional validations, the present study highlights the protective effects of Mathurameha through the EGF/NO/IL-1β regulatory axis. These findings support its potential use as a therapeutic intervention for diabetic vascular complications and provide valuable information for developing more effective anti-diabetic drugs. [Display omitted] • A traditional Thai herbal formula "Mathurameha" showed anti-diabetic activity. • This herbal remedy attenuated high glucose-induced endothelial dysfunctions. • Mathurameha exerted its anti-diabetic mechanism through the EGF/NO/IL-1β regulatory axis. [ABSTRACT FROM AUTHOR]

Smoking remains a significant health problem in patients with type 2 diabetes mellitus. This study compared intracellular Ca2+ ([Ca2+] i) in microglia, neurons, and astrocytes in the presence of high glucose (HG) and nicotine and evaluated the effects of Lavandula angustifolia Mill. essential oil (LEO) on this process. [Ca2+] i concentrations were measured by monitoring the fluorescence of Fura-2 acetoxymethyl ester. Treatment with HG and nicotine significantly increased [Ca2+] i in both microglia and neurons through Ca2+ influx from extracellular sources. This increased Ca2+ influx in microglia, however, was significantly reduced by LEO, an effect partially inhibited by the Na+/Ca2+ exchanger (NCX) inhibitor Ni2+. Ca2+ influx in neuron-like cells pretreated with HG plus nicotine was also significantly decreased by LEO, an effect partially inhibited by the L-type Ca2+ channel blocker nifedipine and the T-type Ca2+ channel blocker mibefradil. LEO or a two-fold increase in the applied number of astrocytes attenuated Ca2+ influx caused by high glucose and nicotine in the mixed cells of the microglia, neuron-like cells and astrocytes. These findings suggest that LEO can regulate HG and nicotine-induced Ca2+ influx into microglia and neurons through two distinct mechanisms. [Display omitted] • Lavandula angustifolia Mill. (LEO) reduces high glucose and nicotine-induced Ca2+ influx in microglia via forward mode of NCX. • LEO reduces high glucose and nicotine-induced Ca2+ influx in neuron-like cells by blocking of L- and T-type Ca2+ channels. • LEO treatment may be a strategy for preventing the development of neurodegenerative diseases by hyperglycemia and nicotine. [ABSTRACT FROM AUTHOR]

[Display omitted] Bitter taste receptors (TAS2Rs) Tas2r108 gene possesses a high abundance in mouse kidney; however, the biological functions of Tas2r108 encoded receptor TAS2Rs member 4 (TAS2R4) are still unknown. In the present study, we found that mouse TAS2R4 (mTAS2R4) signaling was inactivated in chronic high glucose-stimulated mouse podocyte cell line MPC, evidenced by the decreased protein expressions of mTAS2R4 and phospholipase C β2 (PLCβ2), a key downstream molecule of mTAS2R4 signaling. Nonetheless, agonism of mTAS2R4 by quinine recovered mTAS2R4 and PLCβ2 levels, and increased podocyte cell viability as well as protein expressions of ZO-1 and nephrin, biomarkers of podocyte slit diaphragm, in high glucose-cultured MPC cells. However, blockage of mTAS2R4 signaling with mTAS2R4 blockers γ-aminobutyric acid and abscisic acid, a Gβγ inhibitor Gallein, or a PLCβ2 inhibitor U73122 all abolished the effects of quinine on NLRP3 inflammasome and p-NF-κB p65 as well as the functional podocyte proteins in MPC cells in a high glucose condition. Furthermore, knockdown of mTAS2R4 with lentivirus-carrying Tas2r108 shRNA also ablated the effect of quinine on the key molecules of the above inflammatory signalings and podocyte functions in high glucose-cultured MPC cells. In summary, we demonstrated that activation of TAS2R4 signaling alleviated the podocyte injury caused by chronic high glucose, and inhibition of NF-κB p65 and NLRP3 inflammasome mediated the protective effects of TAS2R4 activation on podocytes. Moreover, activation of TAS2R4 signaling could be an important strategy for prevention and treatment of diabetic kidney disease. [ABSTRACT FROM AUTHOR]

Diabetes mellitus is a chronic metabolic disease with prolonged low-grade inflammation and impaired cellular function, leading to poor wound healing. The treatment of diabetic wounds remains challenging due to the complex wound microenvironment. In view of the prominence of fish scales in traditional Chinese medicine and their wide application in modern medicine, we isolated the intercellular components in the scales of sea bass, obtained a natural composite hydrogel, fish scales gel (FSG), and applied it to diabetic chronic wounds. FSG was rich in collagen-like proteins, and possessed low-temperature gelation properties. In vitro, FSG was biocompatible and promoted fibroblast proliferation by approximately 40 %, endothelial cell migration by approximately 20 % and activated the M1 macrophages. In addition, FSG restored the function of fibroblasts and vascular endothelial cells damaged by high glucose. Importantly, FSG normalized the acute inflammatory response to impaired macrophages in a high-glucose microenvironment. Transcriptome analysis implies that this mechanism may involve enhanced cell signaling and cellular communication, improved sensitivity to cytokines, and activation of the TNF signaling pathway. Animal experiments confirmed that FSG significantly improved wound closure by approximately 15 % in diabetic rats, showing similar effects to acute wounds. In conclusion, the regulation of multiple cellular functions by FSG, especially the counterintuitive ability to induce acute inflammation, promoted diabetic wound healing and provides a novel therapeutic strategy for wound repair in diabetic patients. [Display omitted] • A natural composite hydrogel (FSG) was obtained from the scales of sea bass. • FSG promoted cells proliferation, migration and M1 polarization. • FSG restored the function of cells damaged by high glucose. • FSG normalized the acute inflammatory response through TNF signaling pathway. • FSG significantly promoted wound repair in diabetic rats. [ABSTRACT FROM AUTHOR]

Diabetic liver injury (DLI) is a chronic complication of the liver caused by diabetes, and its has become one of the main causes of nonalcoholic fatty liver disease (NAFLD). The gasdermin E (GSDME)-dependent pyroptosis signaling pathway is involved in various physiological and pathological processes; however, its role and mechanism in DLI are still unknown. This study was performed to investigate the role of GSDME-mediated pyroptosis in AML-12 cell injury induced by high glucose and to evaluate the therapeutic potential of caspase-3 inhibition for DLI. The results showed that high glucose activated apoptosis by regulating the apoptotic protein levels including Bax, Bcl-2, and enhanced cleavage of caspase-3 and PARP. Notably, some of the hepatocytes treated with high glucose became swollen, accompanied by GSDME-N generation, indicating that pyroptosis was further induced by active caspase-3. Moreover, the effects of high glucose on AML-12 cells could be partly reversed by a reactive oxygen scavenger (NAC) and caspase-3 specific inhibitor (Z -DEVD-FMK), which suggests high glucose induced GSDME-dependent pyroptosis in AML-12 cells through increasing ROS levels and activating caspase-3. In conclusion, our results show that high glucose can induce pyroptosis in AML-12 cells, at least in part, through the ROS/caspase-3/GSDME pathway，and inhibition of caspase-3 can ameliorate high glucose-induced hepatocyte injury, providing an important basis for clarifying the pathogenesis and treatment of DLI. • High glucose toxicity was evaluated in AML-12 cells. • High glucose could induce pyroptosis through ROS/caspase-3/GSDME pathway in AML-12 cells. • Inhibition of caspase-3 could attenuate high glucose-induced pyroptosis and apoptosis, and improve hepatocellular injury. [ABSTRACT FROM AUTHOR]

[Display omitted] • High glucose changed electrophysiological properties and caused neuronal injury. • High glucose decreased the expression of PSD-95. • Rapamycin protected against neuronal injury caused by high glucose. • Rapamycin increased the expression of PSD-95 caused by high glucose. Diabetic neuropathy is one of the most common complications in patients with diabetes and leads to cognitive impairment. It is suggested that protracted hyperglycemia is the main trigger of cognitive deficits in diabetes and causes hippocampal abnormalities. Rapamycin, an inhibitor of mammalian target of rapamycin complex 1 (mTORC1), can significantly ameliorate cognitive deficits in neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease and Huntington disease. We employed whole-cell patch clamping to examine the effects of rapamycin on neuronal electrophysiological characteristics of the hippocampal dentate gyrus in mice under the condition of high glucose. We recorded the action potentials (APs) and the miniature excitatory postsynaptic currents (mEPSCs) of dentate gyrus neurons. We found that high glucose increased the half-width, the duration and decreased the peak amplitude of Aps as well as the inter-event interval (IEI) of mEPSCs in hippocampal dentate gyrus neurons. However, rapamycin pre-treatment reversed the changes induced by high glucose. Moreover, we demonstrated that rapamycin pre-treatment reversed the down-regulation of postsynaptic density protein 95 (PSD-95) expression caused by high glucose. Therefore, pre-treatment with rapamycin could ameliorate high glucose-induced alteration of synaptic transmission in the hippocampal dentate gyrus. [ABSTRACT FROM AUTHOR]

Diabetic cardiomyopathy lacks effective and novel methods. Hydrogen sulfide (H 2 S) as the third gasotransmitter plays an important role in the cardiovascular system. Our study was to elucidate the protective effect and possible mechanism of H 2 S on diabetic cardiomyopathy from the perspective of necroptosis. Leptin receptor deficiency (db/db) mice and streptozotocin (STZ)-induced diabetic cystathionine-γ-lyase (CSE) knockout (KO) mice were investigated. In addition, cardiomyocytes were stimulated with high glucose. We found that plasma H 2 S level, myocardial H 2 S production and CSE mRNA expression was impaired in the diabetic mice. CSE deficiency exacerbated diabetic cardiomyopathy, and promoted myocardial oxidative stress, necroptosis and inflammasome in STZ-induced mice. CSE inhibitor dl -propargylglycine (PAG) aggravated cell damage and oxidative stress, deteriorated necroptosis and inflammasome in cardiomyocytes with high glucose stimulation. H 2 S donor sodium hydrosulfide (NaHS) improved diabetic cardiomyopathy, attenuated myocardial oxidative stress, necroptosis and the NLR family pyrin domain-containing protein 3 (NLRP3) in db/db mice. NaHS also alleviated cell damage, oxidative stress, necroptosis and inflammasome in cardiomyocytes with high glucose stimulation. In Conclusion, H 2 S deficiency aggravated mitochondrial damage, increased reactive oxygen species accumulation, promoted necroptosis, activated NLRP3 inflammasome, and finally exacerbated diabetic cardiomyopathy. Exogenous H 2 S supplementation alleviated necroptosis to suppress NLRP3 inflammasome activation and attenuate diabetic cardiomyopathy via mitochondrial dysfunction improvement and oxidative stress inhibition. Our study provides the first evidence and a new mechanism that necroptosis inhibition by a pharmacological manner of H 2 S administration protected against diabetic cardiomyopathy. It is beneficial to provide a novel strategy for the prevention and treatment of diabetic cardiomyopathy. [Display omitted] ● H 2 S production was impaired in db/db mice and streptozotocin-induced diabetic mice. ● CSE knockout exacerbated diabetic cardiomyopathy in streptozotocin-induced mice. ● CSE knockout promoted necroptosis and inflammasome in diabetic cardiomyopathy. ● CSE inhibitor aggravated necroptosis in high glucose stimulated cardiomyocytes. ● Exogenous H 2 S alleviated necroptosis to protect against diabetic cardiomyopathy. [ABSTRACT FROM AUTHOR]

There is significant interest in understanding the cellular mechanisms responsible for expedited healing response in various oral tissues and how they are impacted by systemic diseases. Depending upon the types of oral tissue, wound healing may occur by predominantly re-eptihelialization, by re-epithelialization with substantial new connective tissue formation, or by a a combination of both plus new bone formation. As a result, the cells involved differ and are impacted by systemic diaseses in various ways. Diabetes mellitus is a prevalent metabolic disorder that impairs barrier function and healing responses throughout the human body. In the oral cavity, diabetes is a known risk factor for exacerbated periodontal disease and delayed wound healing, which includes both soft and hard tissue components. Here, we review the mechanisms of diabetic oral wound healing, particularly on impaired keratinocyte proliferation and migration, altered level of inflammation, and reduced formation of new connective tissue and bone. In particular, diabetes inhibits the expression of mitogenic growth factors whereas that of pro-inflammatory cytokines is elevated through epigenetic mechanisms. Moreover, hyperglycemia and oxidative stress induced by diabetes prevents the expansion of mesengenic cells that are involved in both soft and hard tissue oral wounds. A better understanding of how diabetes influences the healing processes is crucial for the prevention and treatment of diabetes-associated oral complications. [ABSTRACT FROM AUTHOR]

• AS-IV has a protective effect on the retina of diabetic rats. • AS-IV may reduce HG-induced damage to RGCs by inhibiting oxidative stress response. • AS-IV down-regulated the mRNA expression levels of HIF1α, AKT1, CTNNB1, SMAD2, SMAD3 and IL-1β in HG-induced RGCs. To examine the therapeutic mechanism of astragaloside IV (AS-IV) in the management of retinal ganglion cell (RGC) injury induced by high glucose (HG), a comprehensive approach involving the integration of network pharmacology and conducting in vitro and in vivo experiments was utilized. A rat model of diabetic retinopathy (DR) injury was created by administering streptozotocin through intraperitoneal injection. Additionally, a model of RGC injury induced by HG was established using a glucose concentration of 0.3 mmol/mL. Optical coherence tomography (OCT) images were captured 8 weeks after the injection of AS-IV. AS-IV and FBS were added to the culture medium and incubated for 48 h. The viability of cells was assessed using a CCK-8 assay, while the content of reactive oxygen species (ROS) was measured using DCFH-DA. Apoptosis was evaluated using Annexin V-PI. To identify the targets of AS-IV, hyperglycemia, and RGC, publicly available databases were utilized. The Metascape platform was employed for conducting GO and KEGG enrichment analyses. The STRING database in conjunction with Cytoscape 3.7.2 was used to determine common targets of protein–protein interactions (PPIs) and to identify the top 10 core target proteins in the RGC based on the MCC algorithm. qRT-PCR was used to measure the mRNA expression levels of the top10 core target proteins in RGCs. OCT detection indicated that the thickness of the outer nucleus, and inner and outer accessory layers of the retina increased in the AS-IV treated retina compared to that in the DM group but decreased compared to that in the CON group. Coculturing RGC cells with AS-IV after HG induction resulted in a significant increase in cell viability and a decrease in ROS and apoptosis, suggesting that AS-IV can reduce damage to RGC cells caused by high glucose levels by inhibiting oxidative stress. There were 14 potential targets of AS-IV in the treatment of RGC damage induced by high glucose levels. The top 10 core target proteins identified by the MCC algorithm were HIF1α, AKT1, CTNNB1, SMAD2, IL6, SMAD3, IL1β, PPARG, TGFβ1, and NOTCH3. qRT-PCR analysis showed that AS-IV could upregulate the mRNA expression levels of SMAD3, TGF-β1, and NOTCH3, and downregulate the mRNA expression levels of HIF1α, AKT1, CTNNB1, SMAD2, SMAD3, and IL-1β in high glucose-induced RGC cells. The findings of this study validate the efficacy of astragaloside IV in the treatment of DR and shed light on the molecular network involved. Specifically, HIF1α, AKT1, CTNNB1, SMAD2, SMAD3, and IL-1β were identified as the crucial candidate molecules responsible for the protective effects of astragaloside IV on RGCs. [ABSTRACT FROM AUTHOR]

• High glucose intake could induce Th17 cell responses and exacerbate experimental autoimmune prostatitis (EAP). • high glucose intake exacerbates EAP through mitochondrial reactive oxygen species-dependent TGF-β activation-mediated Th17 differentiation. • A high-glucose diet may have detrimental effects on chronic prostatitis/ chronic pelvic pain syndrome (CP/CPPS) patients. Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is a common inflammatory immune disease of the urogenital system. High glucose intake is considered to be a potential promoter of autoimmune diseases. However, the influence of high glucose intake on CP/CPPS is unknown. This research aimed to explore the influences of high glucose intake on experimental autoimmune prostatitis (EAP), a valid animal model of CP/CPPS, and the underlying mechanism. NOD mice received 20% glucose water or normal water treatment during EAP induction. EAP severity and Th17 cell responses were evaluated. Then, we explored the effects of an IL-17A neutralizing antibody, an inhibitor of TGF-β, the reactive oxygen species (ROS) inhibitor NAC, and the mitochondrial ROS (mtROS) antioxidant MitoQ on glucose-fed EAP mice. The results demonstrated that high glucose intake aggravated EAP severity and promoted Th17 cell generation, which could be ameliorated by the neutralization of IL-17A. In vitro experiments showed that high dextrose concentrations promoted Th17 cell differentiation through mtROS-dependent TGF-β activation. Treatment with TGF-β blockade, NAC, or MitoQ suppressed Th17 cell generation both in vivo and in vitro, resulting in the amelioration of EAP manifestations caused by high glucose intake. This study revealed that high glucose intake exacerbates EAP through mtROS-dependent TGF-β activation-mediated Th17 differentiation. Our results may provide insights into the molecular mechanisms underlying the detrimental effects of an environmental factor, such as high glucose intake, on CP/CPPS. [ABSTRACT FROM AUTHOR]

Proinsulin C-peptide, a biologically active polypeptide released from pancreatic β-cells, is known to prevent hyperglycemia-induced microvascular leakage; however, the role of C-peptide in migration and invasion of cancer cells is unknown. Here, we investigated high glucose-induced migration and invasion of ovarian cancer cells and the inhibitory effects of human C-peptide on metastatic cellular responses. In SKOV3 human ovarian cancer cells, high glucose conditions activated a vicious cycle of reactive oxygen species (ROS) generation and transglutaminase 2 (TGase2) activation through elevation of intracellular Ca2+ levels. TGase2 played a critical role in high glucose-induced ovarian cancer cell migration and invasion through β-catenin disassembly. Human C-peptide inhibited high glucose-induced disassembly of adherens junctions and ovarian cancer cell migration and invasion through inhibition of ROS generation and TGase2 activation. The preventive effect of C-peptide on high glucose-induced ovarian cancer cell migration and invasion was further demonstrated in ID8 murine ovarian cancer cells. Our findings suggest that high glucose conditions induce the migration and invasion of ovarian cancer cells, and human C-peptide inhibits these metastatic responses by preventing ROS generation, TGase2 activation, and subsequent disassembly of adherens junctions. [Display omitted] • High glucose conditions activated a vicious cycle of ROS generation and TGase2 activation. • TGase2 played a critical role in high glucose-induced ovarian cancer cell migration and invasion. • C-peptide attenuated these metastatic responses by inhibiting the vicious cycle. • C-peptide is a potential inhibitor of hyperglycemia-induced ovarian cancer metastasis. [ABSTRACT FROM AUTHOR]

Introduction: Inhibiting apoptosis of trophoblasts in women with gestational diabetes mellitus (GDM) is expected to guarantee adequate nutrition for the fetus and avoid abortion. MiR-193b is one of the most downregulated miRNAs in GDM patients. However, less is known about the role of miR-193b in autophagy and apoptosis in GDM patients.Methods: We detected the expression of miR-193b in GDM patients. Then, we cultured human trophoblasts (HTR8 cells) with high glucose (HG) to simulate a diabetic environment in vitro, and further explored the effects of miR-193b on apoptosis and autophagy of HG-treated HTR8 cells.Results: The expression of miR-193b was significantly downregulated in the peripheral blood of GDM patients compared with healthy controls, and decreased miR-193b caused apparent autophagy and a substantially high apoptosis rate in HG-treated HTR8 cells. These effects were reversed by enhancing miR-193b expression or using the autophagy inhibitor 3-MA. Inhibiting miR-193b induced the pro-autophagic, cytostatic, and pro-apoptotic effects reduced by 3-MA in HTR8 cells upon HG treatment. Moreover, the expression of insulin-like growth factor-binding protein 5 (IGFBP5) was upregulated notably in the peripheral blood of GDM patients, and IGFBP5 appears to represent a direct miR-193b target. Note that silencing IGFBP5 blocked autophagy and apoptosis in HG-treated HTR8 cells, an effect that was diminished by inhibiting miR-193b.Conclusion: Our data indicate that aberrantly low expression of miR-193b in HG-induced trophoblasts results in massive apoptosis events by upregulating IGFBP5-induced autophagy, which may trigger GDM. Therefore, miR-193b may became a potential target for GDM therapy. [ABSTRACT FROM AUTHOR]

Chinese herbal compound Nao-Fu-Cong (NFC) has been mainly used to treat cognitive disorders in Traditional Chinese Medicine (TCM). The present study aimed to investigate whether its neuroprotective effects might be related to the inhibition of JNK/CHOP/Bcl2-mediated apoptosis pathway or not. We randomly assigned STZ (60 mg·kg−1)-induced diabetic rats into control group, diabetic model group and NFC groups (low-dose, medium-dose and high-dose). The primary culture of hippocampal neurons were transferred into different culture media on the third day. The cells were then divided into control group, high-glucose group, NFC (low-dose, medium-dose and high-dose) groups, CHOP si-RNA intervention group, JNK pathway inhibitor SP600125 group and oxidative stress inhibitor N -acetylcysteine (NAC) group. NFC significantly improved the cognitive function of diabetic rats, and had neuroprotective effect on hippocampal neurons cultured in high glucose. Further research results showed that NFC could reduce the apoptosis of hippocampal neurons in rats with diabetic cognitive dysfunction. NFC had inhibitory effects on CHOP/JNK apoptosis pathway induced by high glucose, and also decreased the levels of ROS and increased the mitochondrial membrane potential. These suggested that the neuroprotective effect of NFC might be related to the inhibition of CHOP and JNK apoptotic signaling pathways, and the cross pathway between oxidative stress and mitochondrial damage pathway. [ABSTRACT FROM AUTHOR]

EDA2R is a member of the large family of tumor necrosis factor receptor (TNFR). Previous studies suggested that EDA2R expression might be increased in the kidneys of diabetic mice. However, its mRNA and protein expression in kidneys were not analyzed; moreover, its role in the development of diabetic kidney disease was not explored. Here we analyzed the mRNA and protein expressions of EDA2R in diabetic kidneys and examined its role in the podocyte injury in high glucose milieu. By analysis with real-time PCR, Western blotting, we found that both the mRNA and protein levels of EDA2R were increased in the kidneys of diabetic mice. Immunohistochemical studies revealed that EDA2R expression was enhanced in both glomerular and tubular cells of diabetic mice and humans. In vitro studies, high glucose increased EDA2R expression in cultured human podocytes. Overexpression of EDA2R in podocytes promoted podocyte apoptosis and decreased nephrin expression. Moreover, ED2AR increased ROS generation in podocytes, while inhibiting ROS generation attenuates EDA2R-mediated podocyte injury. In addition, EDA2R silencing partially suppressed high glucose-induced ROS generation, apoptosis, and nephrin decrease. Our study demonstrated that high glucose increases EDA2R expression in kidney cells and that EDA2R induces podocyte apoptosis and dedifferentiation in high glucose milieu partially through enhanced ROS generation. • EDA2R expression is increased in the glomerular and tubular cells of diabetic mice and patients. • High glucose induces EDA2R expression in podocytes. • Overexpression of EDA2R promotes podocyte apoptosis and dedifferentiation. • EDA2R suppression attenuates high glucose-induced podocyte apoptosis and dedifferentiation. • EDA2R mediates high glucose-induced podocyte injury partially through enhanced ROS generation. [ABSTRACT FROM AUTHOR]

To explore the protective effects of dexmedetomidine (Dex) against high glucose-induced epithelial-mesenchymal transition in HK-2 cells and relevant mechanisms. HK-2 cells were exposed to either glucose or glucose+Dex for 6 h. The production of ROS, morphology of HK-2 cells, and cell cycle were detected. Moreover, the expression of AKT, p-AKT, ERK, p-ERK, PI3K, E-Cadherin, Claudin-1, and α-SMA were determined and compared between HK-2 cells exposed to glucose and those exposed to both glucose and Dex with or without PI3K/AKT pathway inhibitor LY294002 and ERK pathway inhibitor U0126. Compared with HK-2 cells exposed to high level of glucose, the HK-2 cells exposed to both high level of glucose and Dex showed: (1) lower level of ROS production; (2) cell morphology was complete; (3) more cells in G1 phase; (4) lower expression of p-AKT, p-ERK and α-SMA, higher expression of E-Cadherin and Claudin-1. PI3K/AKT inhibitor LY294002 and ERK inhibitor U0126 decreased the expression of p-AKT, p-ERK and α-SMA, and increased the expression of E-Cadherin and Claudin-1. Dex can attenuate high glucose-induced HK-2 epithelial-mesenchymal transition by inhibiting AKT and ERK. [ABSTRACT FROM AUTHOR]

• Excessive ER stress could depress cognition-related proteins expression. • ER stress could negatively regulate p38/ERK-CREB pathway. • ER stress could positively regulate NLRP3-IL-1β pathway. • Activating Nrf2 could effectively ease hippocampal ER stress. Studies have shown that obesity-induced hyperglycemia and hyperlipidemia could cause increased hippocampal endoplasmic reticulum (ER) stress and impaired cognition-related proteins expression, resulting in learning and memory impairment. Meanwhile, aerobic exercise could activate hippocampal nuclear factor erythroid 2-related factor 2 (Nrf2) reducing ER stress. This study investigated the underlying molecular mechanisms of this effect. In order to clarify the relationship among ER stress, Nrf2 signaling and cognition-related proteins expression in vitro , we respectively treated hippocampal cells with high glucose and palmitic acid (PA), ER stress inhibitor 4-phenylbutyrate (4-PBA), and Nrf2 activator Tert-Butylhydroquinone (TBHQ). Results showed that the expression levels of glucose transporter 3 (GLUT3), fatty acid transport protein 1 (FATP1), ER stress biomarkers (GRP78, p-PERK, p-IRE1α and p-eIF2α), ER stress-mediated apoptosis biomarkers (caspase-12, CHOP and Bax/Bcl-2), and the activity of NLRP3-IL-1β inflammatory pathway were significantly increased under high glucose and PA conditions, accompanied with depressed p38/ERK-CREB pathway and decreased levels of brain derived neurotrophic factor (BDNF) and synaptophysin (SYN). On the other hand, both 4-PBA and TBHQ reduced ER stress and reversed the expression of the above-mentioned proteins. Our findings suggest that high glucose and PA could induce excessive ER stress and apoptosis via promoting the overexpression of GLUT3 and FATP1, and ER stress could suppress BDNF and SYN expression through negatively regulating p38/ERK-CREB pathway and positively regulating NLRP3-IL-1β pathway, which could be reversed by activated Nrf2-HO-1 pathway. [ABSTRACT FROM AUTHOR]

Necroptosis is one of a regulated programmed death mode, fibrosis is closely related with cell death. It has been reported that inhibition of necroptosis can play the protective role in cardiac ischemia and reperfusion injury, stroke and other diseases, but the mechanisms of aldehyde dehydrogenases 2 (ALDH2) against high glucose induced neonatal rat ventricular primary cardiomyocytes fibrosis and necroptosis had not been elucidated clearly. This study was to observe the effect of ALDH2 on high glucose (HG) induced myocardial fibrosis and necroptosis in primary rat cardiomyocytes model. In contrast to normal glucose group, in HG group, with the decreases of ALDH2 activity, mRNA and protein levels, the cardiomyocytes viability was decreased, reactive oxygen species (ROS), the inflammation factors - tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β) levels, collagen I (col I) and col III mRNA expressions and tissue inhibitors of matrix metalloproteinase 4 (TIMP4) protein expression were increased, while matrix metalloproteinase 14 (MMP14) protein level, the ratio of MMP14/TIMP4 were decreased, and the necroptosis key factors - the receptor interacting protein 1 (RIP1), RIP3 and mixed lineage kinase domain-like protein (MLKL) at mRNA and protein expressions were increased, the inflammasome core proteins - NLRP3 and ASC protein expressions were also increased, the apoptosis rate and necrosis rate were also increased. When the cardiomyocytes were treated with Alda-1 (the ALDH2 agonist) in HG intervention, the cell viability, ALDH2 activity, mRNA and protein levels, MMP14 protein level, the ratio of MMP14/TIMP4 were higher, ROS and TNF-α, IL-6, IL-1β levels, RIP1, RIP3, MLKL, NLRP3 and ASC expressions, col I and col III, TIMP4 expressions, the apoptosis rate and necrosis rate were lower than in HG group. Daidzin, the antagonist of ALDH2 abolished the role of Alda-1. In summary, ALDH2 maybe is a key regulator in high glucose induced cardiomyocytes injury. Activation of ALDH2 prevented the happening of fibrosis, apoptosis and necroptosis in high glucose induced primary cardiomyocytes injury model, the protective effects were related to the inhibiting of oxidative stress and inflammation, changing of MMP14 and TIMP4, then inhibiting the happening of fibrosis, apoptosis and necroptosis. These findings advance our understanding of the intensive mechanisms of ALDH2's cardioprotection, and provide the targeted basis for clinical diabetes treatment. • Activation of ALDH2 prevented high glucose induced cardiomyocyte fibrosis through inhibiting TIMP4 and increasing MMP14. • Activation of ALDH2 inhibited high glucose induced oxidative stress, inflammation and NLRP3 inflammosome formation. • In high glucose induced cardiomyocytes injury , activation of ALDH2 both prevented apoptosis and necroptosis. [ABSTRACT FROM AUTHOR]

Kaempferol is a natural edible flavonoid reported to treat high-fat diet-induced intestinal inflammation; however, the underlying molecular mechanisms remain unclear. This research aims to investigate the protective effect of kaempferol on the gut-vascular barrier (GVB) induced by high glucose and elucidate the underlying mechanism. Evans blue albumin efflux assay was used to test endothelial cell permeability. The results showed that kaempferol (50 μM) significantly reversed the high glucose-induced monolayer barrier permeability of rat intestinal microvascular endothelial cells (RIMVECs), while kaempferol significantly alleviated the high glucose-induced rarefication of the tight junction protein Claudin-5. Moreover, kaempferol also reduced high glucose-induced angiogenesis and cell migration via inhibiting the VEGFR2/p38 pathway. Kaempferol also protected against high glucose-induced overproduction of intercellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule (VCAM)-1 by inhibiting NF-κB p65 nuclear translocation. In addition, kaempferol had similar effects to the NF-κB inhibitor SN50 in reducing high glucose-induced ICAM-1 expression and endothelial barrier permeabilization. Our findings in part reveal the pathological mechanism of hyperglycemia-related gastrointestinal diseases and underlie the molecular mechanism of kaempferol in inhibiting bowel inflammation from a novel perspective. High glucose caused intestinal vascular endothelial barrier damage, abnormal angiogenesis, and excessive expression of adhesion protein. Kaempferol protects against high glucose-induced microvascular disease through NF-κB pathway, in which the VEGFR2/p38 pathway is involved. [Display omitted] [ABSTRACT FROM AUTHOR]

Metabolism of endothelial cells (ECs) depends on the availability of the energy substrates. Since the endothelium is the first line of defence against inflammation in the cardiovascular system and its dysfunction can lead to the development of cardiovascular diseases, it is important to understand how glucose metabolism changes during inflammation. In this work, glucose uptake was studied in human microvascular endothelial cells (HMEC-1) in high glucose (HG), and additionally in an inflammatory state, using Raman imaging. HG state was induced by incubation of ECs with a deuterated glucose analogue, while the EC inflammation was caused by TNF-α pre-treatment. Spontaneous and stimulated Raman scattering spectroscopy provided comprehensive information on biochemical changes, including lipids and the extent of unsaturation induced by excess glucose in ECs., induced by excess glucose in ECs. In this work, we indicated spectroscopic markers of metabolic changes in ECs as a strong increase in the ratio of the intensity of lipids / (proteins + lipids) bands and an increase in the level of lipid unsaturation and mitochondrial changes. Inflamed ECs treated with HG, revealed enhanced glucose uptake, and intensified lipid production i.a. of unsaturated lipids. Additionally, increased cytochrome c signal in the mitochondrial region indicated higher mitochondrial activity and biogenesis. Raman spectroscopy is a powerful method for determining the metabolic markers of ED which will better inform understanding of disease onset, development, and treatment. • Raman-based analysis of the biochemical phenotype of ECs cultured in different media revealed their adaptive cellular metabolism • The biochemical alteration observed for ECs in glucose-free medium enabled tracking of a change in cellular metabolism upon inflammation • Over time, there is a correlation between inflammation and raised glucose uptake, increased lipid content, and their higher unsaturation level [ABSTRACT FROM AUTHOR]

This study investigated whether scopoletin could protect INS-1 pancreatic β cells from apoptosis and oxidative stress caused by high glucose. Cells were pretreated with glucose (5.5 or 30 mM) and then treated with 0, 5, 10, 25, or 50 μM Scopoletin. Cell viability and insulin secretion were measured in addition to ROS, TBARS, NO and antioxidant enzymes. Western blot analysis and flow cytometric assessment of apoptosis were also carried out. High glucose of 30 mM caused glucotoxicity and cell death in INS-1 pancreatic β cells. However, 5, 10, 25 or 50 μM scopoletin increased the level of cell viability as concentrations increased. The levels of ROS, TBARS, and NO increased by high glucose were significantly decreased after scopoletin treatment. Scopoletin also raised antioxidant enzyme activities up against oxidative stress produced by high glucose. These effects influenced the apoptosis pathway, raising levels of anti-apoptotic protein, Bcl-2, and reducing levels of pro-apoptotic proteins, including JNK, Bax, cytochrome C, and caspase 9. Annexin V/propidium staining indicated that scopoletin significantly lowered high glucose-produced apoptosis. These results indicate that scopoletin can protect INS-1 pancreatic β cells from glucotoxicity caused by high glucose and have potential as a pharmaceutical material to protect the pancreatic β cells. [Display omitted] • Scopoletin can protect INS-1 pancreatic β cells from glucotoxicity caused by high glucose. • Scopoletin protects β-cells from oxidative stress and apoptosis caused by hyperglycemia. • Scopoletin protects pancreatic β cells and restores their capacity for insulin secretion. • Scopoletin could preserve pancreatic β-cells from mitochondria mediated apoptosis. [ABSTRACT FROM AUTHOR]

High glucose induces Schwann cells death and neurotoxicity. Formononetin was originally found in Astragalus membranaceus and showed anti-tumor and anti-neuroinflammation properties. The aim of this study is to explore the molecular mechanism underlying the neuroprotective effects of formononetin and identify its direct protein target. The effects of formononetin on oxidative stress and mitochondrial dysfunction in Schwann cells induced by high glucose were investigated. High glucose treatment significantly induced oxidative stress, mitochondrial dysfunction and apoptosis in Schwann cells, while these effects were partially or completely prevented by co-treatment with formononetin. Mechanistically, we found that SIRT3/PGC-1α/SOD2 pathway was activated by formononetin under high glucose conditions as evidenced by western blotting. Knockdown of SIRT3 by siRNA delivery reversed the protective effects of formononetin on high glucose-induced Schwann cells injury and changes in expression profile of SIRT3 downstream target genes. Molecular docking, thermal shift assay and surface plasmon resonance assay revealed a direct binding between formononetin and SIRT3. Taken together, we identified a novel SIRT3 activator formononetin and revealed its beneficial effects on high glucose-induced neurotoxicity, suggesting that targeting SIRT3 in Schwann cells may be a new approach for treatment of peripheral nerve regeneration related diseases such as diabetic peripheral neuropathy. • Formononetin reduced high glucose-induced apoptosis in Schwann cells. • Formononetin attenuated high glucose-induced oxidative stress and mitochondrial dysfunction. • Formononetin regulated Schwann cells function via activating SIRT3/PGC-1α/SOD2 pathway. • Formononetin directly binds to SIRT3. [ABSTRACT FROM AUTHOR]

High glucose (HG)-induced podocyte injury contributes to the pathogenesis of diabetic nephropathy, a severe complication of diabetes. Bromodomain-containing protein 4 (BRD4) has emerged as a critical regulator for cell injury. However, whether BRD4 participates in HG-induced podocyte injury remains unclear. In this study, we aimed to explore the potential role of BRD4 in regulating HG-induced podocyte injury and its underlying molecular mechanism. HG exposure significantly upregulated BRD4 in podocytes. BRD4 inhibition by small interfering RNA or its chemical inhibitor (JQ1) markedly repressed HG-induced apoptosis and reactive oxygen species (ROS) production. By contrast, BRD4 overexpression exacerbated HG-induced podocyte injury. Moreover, BRD4 inhibition potentiated nuclear factor (erythroid-derived 2)-like 2 (Nrf2) signaling associated with suppression of Kelch-like ECH-associated protein (Keap1). BRD4 inhibition promoted Nrf2 nuclear translocation and upregulated the transcriptional activity of Nrf2/antioxidant response element (ARE). However, Nrf2 silencing partially reversed BRD4-inhibition-mediated protection against HG-induced podocyte injury. Overall, these results suggest that BRD4 inhibition confers cytoprotection against HG injury in podocytes through potentiation of Nrf2/ARE antioxidant signaling. This finding implicates BRD4/Nrf2/ARE signaling in the pathogenesis of diabetic nephropathy. Image 1 • BRD4 is induced by HG in podocytes in vitro. • BRD4 inhibition protects podocytes from HG-induced injury. • BRD4 inhibition reinforces Nrf2 signaling by inhibiting Keap1. • Nrf2 inhibition reverses BRD4-inhibition-mediated protection effect. [ABSTRACT FROM AUTHOR]

• High glucose significantly damages the OGD/R-treated neuronal cells via ER stress. • High glucose significantly increases RTN1-C in OGD/R-treated neuronal cells. • High glucose-damages were reversed by knocking down RTN1-C in OGD/R cells. Patients suffering from diabetes mellitus experience poor outcomes after ischemic stroke. RTN1-C, ER-associated proteins localized in endoplasmic reticulum (ER) membrane, plays an important role in ER stress-induced apoptosis and regulates cellular susceptibility to different apoptosis pathways. Overexpression of RTN1-C can aggravate cerebral ischemia/reperfusion injury (IRI). ER stress plays a crucial role in hyperglycemia-aggravated cerebral IRI. In this study, we aimed to investigate the role of RTN1-C in high glucose-aggravated OGD/R-induced cell damage. N2a cells and primary neuronal cells were cultured in normal glucose or high glucose conditions. We used a model of oxygen-glucose deprivation followed by reoxygenation (OGD/R). RTN1-C shRNA was used to knock down RTN1-C. The chemical chaperone 4-phenylbutyric acid (4-PBA) is a low molecular weight fatty acid that has the ability to stabilize mutant proteins and facilitate their folding, was used to inhibited ER stress. Cell viability and apoptosis were measured by CCK-8 and flow cytometry assays. The contents of ER stress-associated proteins, such as GRP78, cleaved caspase-12, CHOP and cleaved caspase-3, were detected by western blot. High glucose significantly decreased cell viability and increased cell apoptosis in OGD/R-treated neuronal cells. The contents of GRP78, cleaved caspase-12, CHOP and cleaved caspase-3 under high glucose conditions were higher than those under normal glucose conditions after OGD/R. Importantly, inhibition of ER stress by 4-PBA alleviated the high glucose-aggravated OGD/R-induced cell damage. Here, we demonstrated that high glucose increases RTN1-C expression in OGD/R-treated cells. More importantly, knockdown of RTN1-C expression dramatically reversed the high glucose-aggravated change in cell viability and apoptosis and relieved ER stress in OGD/R-treated cells. High glucose significantly increases RTN1-C expression in OGD/R-treated cells. RTN1-C affects high glucose-treated OGD/R cells by exacerbating ER stress. [ABSTRACT FROM AUTHOR]

Diabetes is an independent risk factor for knee osteoarthritis (OA), and hyperglycaemia-induced inflammation is considered to play an important role in their connection. The Toll-like receptor 4 (TLR4) regulates inflammatory responses in several pathological conditions including diabetes and OA. However, its role in diabetes-associated OA is poorly understood. In this study, we found that TLR4 expression was higher in OA cartilage from patients with type 2 diabetes mellitus (T2DM) than that from non-T2DM patients. Similarly, its expression was induced in primary mouse chondrocytes treated with high glucose, which suggests that TLR4 upregulation in T2DM-associated OA cartilage may originate from hyperglycaemia stimulation. We further discovered that TLR4 promoted high glucose-induced catabolic and inflammatory responses in chondrocytes, and mechanistically, these effects could be explained by the exacerbated activation of the transcription factor nuclear factor kappa B (NF-κB) pathway, since its inhibition by Bay 11-7082 abrogated TLR4 effects on high glucose-treated chondrocytes. Taken together, these findings may reveal a promotive role of TLR4 in regulating hyperglycaemia-induced catabolism and inflammation in T2DM-associated OA, and also implicate that TLR4 inhibition might be of therapeutic significance in treating T2DM-associated OA. [ABSTRACT FROM AUTHOR]

High glucose (HG) has the potential to cause vascular endothelial cell injury, while microRNAs (miRNAs) play a key role in treating endothelial cell injury. CXC chemokine receptor-4 (CXCR4) is reported to be expressed in vascular endothelial cells. Hence, this study investigated role of miR-9-5p in the angiogenesis and apoptosis of HG-induced human umbilical vascular endothelial cells (HUVECs) injury. Dual luciferase reporter gene assay verified that miR-9-5p targeted CXCR4. RT-qPCR and western blot analysis revealed that miR-9-5p was down-regulated, meanwhile CXCR4 was up-regulated in the HG-induced HUVECs. HUVECs were cultured in 30 mmol/L HG in vitro, and then transfected with miR-9-5p mimic or CXCR4 siRNA to identify the effect of miR-9-5p on cell activity, angiogenesis, apoptosis, and inflammation of HG-induced HUVECs. The results suggested that overexpression of miR-9-5p or silencing of CXCR4 in HG-induced HUVECs increased cell proliferation and tubule length, while decreasing the apoptosis rate and the expression of inflammatory factors. Furthermore, miR-9-5p inhibited the phosphorylation of extracellular regulated protein kinases (ERK), protein kinase B (AKT), and Mammalian Target of Rapamycin (mTOR) proteins via downregulation of CXCR4. Therefore, overexpression of miR-9-5p suppressed the mitogen-activated protein kinase (MAPK)/ERK and the PI3K/AKT/mTOR pathway by inhibiting CXCR4, thereby reducing HG-induced injury in HUVECs. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Ca2+/calmodulin-dependent protein kinase II (CaMKII) plays an important role in the cardiovascular system. However, the potential protective role of inhibitor 1 of protein phosphatase 1 (I1PP1), which is able to regulate CaMKII, in high glucose-induced cardiomyocytes injury remains unknown. In the present study, cardiomyocytes were transfected with I1PP1 adenovirus to inhibit protein phosphatase 1 (PP1) expression. After the cardiomyocytes were subjected to high glucose stimulation for 48 h, quantitative real-time PCR was used to detect CaMKIIδ alternative splicing. Lactate dehydrogenase (LDH) release and adenosine triphosphate (ATP) level were measured to assess cell damage and energy metabolism respectively. CaMKII activity was represented as phospholamban (PLB) phosphorylation, CaMKII phosphorylation (p-CaMKII) and oxidation (ox-CaMKII). Dihydroethidium (DHE), MitoSOX and JC-1 staining were used to assess oxidative stress and mitochondrial membrane potential. Necroptosis was evaluated by receptor interacting protein kinase 3 (RIPK3) expression, TUNEL and cleaved-caspase 3 levels. RIPK3, mixed lineage kinase domain like protein (MLKL) and dynamin-related protein 1 (DRP1) expressions were also detected. We found that high glucose disordered CaMKIIδ alternative splicing. I1PP1 over-expression suppressed PLB phosphorylation, ox-CaMKII, DRP1, RIPK3 and cleaved-caspase 3 proteins expression, decreased LDH release, attenuated necroptosis, increased ATP level, inhibited oxidative stress, and elevated mitochondrial membrane potential in high glucose-stimulated cardiomyocytes. However, there was no effect on phosphorylation of MLKL (p-MLKL), p-CaMKII, and receptor interacting protein kinase 1 (RIPK1) expression. Altogether, I1PP1 over-expression alleviated CaMKIIδ alternative splicing disorder, suppressed CaMKII oxidation, reduced reactive oxygen species (ROS) accumulation and inhibited necroptosis to attenuate high glucose-induced cardiomyocytes injury. [ABSTRACT FROM AUTHOR]

Abstract Erianin is the major bibenzyl compound found in Dendrobium chrysotoxum Lindl. The current study was designed to investigate the protective effects of erianin on high glucose-induced injury in cultured renal tubular epithelial cells (NRK-52E cells) and determine the possible mechanisms for its effects. NRK-52E cells were pretreated with erianin (5, 10, 25 or 50 nmol/L) for 1 h followed by further exposure to high glucose (30 mmol/L, HG) for 48 h. Erianin concentration dependently enhanced cell viability followed by HG treatment in NRK-52E cells. HG induced reactive oxygen species (ROS) generation, malondialdehyde production, and glutathione deficiency were recovered in NRK-52E cells pretreated with erianin. HG triggered cell apoptosis via the loss of mitochondrial membrane potential, depletion of adenosine triphosphate, upregulation of caspases 9 and 3, enhancement of cytochrome c release, and subsequent interruption of the Bax/Bcl-2 balance. These detrimental effects were ameliorated by erianin. HG also induced activation of p53, JNK, p38 mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) in NRK-52E cells, which were blocked by erianin. The results suggest that treatment NRK-52E cells with erianin halts HG-induced renal dysfunction through the suppression of the ROS/MAPK/NF-κB signaling pathways. Our findings provide novel therapeutic targets for diabetic nephropathy. Highlights • High glucose caused oxidative stress and cellular damage in NRK-52E cells. • Erianin ameliorated high glucose-induced cytotoxicity in NRK-52E cells. • Erianin prevented NRK-52E cells from high glucose-induced mitochondrial dysfunction. • Erianin suppressed ROS/MAPK/NF-κB signaling in NRK - 52E cells exposed to a high glucose. [ABSTRACT FROM AUTHOR]

Highlights • The naturally occurring compound trehalose is a potent de novo autophagy activator. • Trehalose restores autophagy suppressed by high glucose. • Trehalose induces functional autophagy including mitophagy and reticulophagy. • Trehalose may be a potential therapeutic option for human diseases manifested with impaired autophagy. Abstract Autophagy is required for neurulation, and autophagy activators with minimal toxicity, such as the natural compound trehalose, a nonreducing disaccharide, possess high therapeutic value. To determine whether trehalose directly induces autophagy, FITC-labeled trehalose was used for tracing its presence in autophagosome complexes. Trehalose was as potent as rapamycin and starvation in inducing de novo autophagosome formation and increasing autophagosome flux in GFP-LC3 reporter cells and C17.2 neural stem cells. Trehalose effectively reversed high glucose-suppressed autophagy and reduced p62 protein expression. Trehalose abolished the disruption of autophagosome complexes under high glucose conditions in vitro and maternal diabetes in vivo. Autophagosomes induced by trehalose were functionally active, forming mitophagy and reticulophagy in removing damaged cellular organelles in neuroepithelial cells exposed to maternal diabetes. Thus, trehalose directly participated in functional autophagosome generation by incorporating itself into autophagosomes. These findings provide the mechanistic basis for the use of trehalose in preventing disruptive autophagy-associated pathogenesis. [ABSTRACT FROM AUTHOR]

Abstract Aims The therapeutic strategies for diabetic retinopathy (DR) are disappointing. Ginsenoside Rg1 (Rg1) extracted from Panax ginseng can induce glucose uptake and lower oxidative stress. We aimed to explore the effect of Rg1 on DR using human retinal pigment epithelium cells (ARPE-19). Main methods ARPE-19 cells were grown in high glucose (HG) to simulate DR. Cell viability, apoptosis, ROS generation and miR-26a level were examined by CCK-8 assay, flow cytometry assay, DCFH-DA staining and RT-qPCR, respectively. Expression of proteins associated with viability, apoptosis and oxidative stress was measured by Western blot analysis. Effects of Rg1 on HG-induced alteration were assessed. Moreover, whether miR-26a was involved in Rg1-associated modulation was verified. Finally, the involvements of the ERK and Wnt/β-catenin pathways were analyzed by Western blot analysis. Key findings HG reduced cell viability while promoted apoptosis and oxidative stress in ARPE-19 cells. Rg1 ameliorated HG-induced cell injury. The expression of miR-26a was up-regulated by Rg1 in HG-treated cells, and miR-26a inhibition obviously reversed the effects of Rg1 on HG-treated cells. Finally, we found the ERK and Wnt/β-catenin pathways were inhibited by Rg1 through up-regulation of miR-26a. Significance Rg1 protected ARPE-19 cells against HG-induced injury through up-regulating miR-26a, along with inhibition of the ERK and Wnt/β-catenin pathways. Rg1 might be a potential therapeutic drug for DR. [ABSTRACT FROM AUTHOR]

Abstract Aims This study explored the role of the BMP4/Smad1 signaling pathway in mesangial matrix expansion during the process of diabetic nephropathy. Main methods Diabetic rats were induced by high-fat feeding followed by an intraperitoneal injection of streptozotocin. Glomerular lesions were examined. Immunohistochemical analysis was performed in order to identify BMP4/Smad1 signaling proteins (BMP4, ALK3, and Smad1) and mesangial ECM proteins (Col1 and Col4) in kidney tissue. Cell proliferation and the expression of BMP4, Smad1 and Col4 were determined in cultured mesangial cells exposed to high glucose. The specific regulatory role of BMP4 was evaluated by detecting BMP4/Smad1 signaling pathway proteins and mesangial ECM proteins after blocking BMP4 both at the gene and protein levels. Key findings Rats with DN exhibited mesangial expansion and a thickened glomerular basement membrane. Immunohistochemical analysis of glomeruli showed increased expression of BMP4, Smad1, ALK3, Col1, and Col4 but less expression of MMP9 than observed in controls. High glucose induced slight proliferation of cultured rat mesangial cells after 48 h of incubation but there was no significant different from the control (p > 0.05). High glucose activated the BMP4/Smad1 signaling pathway and stimulated Col4 expression in mesangial cells. Both silencing of the bmp4 gene (with siRNA) and blocking BMP4 protein signaling (with the BMP4 protein antagonist Noggin) reduced the expression of ALK3, Smad1, Col4, and Col1 in high glucose-stimulated mesangial cells. Significance The BMP4/Smad1 signaling pathway is crucial to the progression of mesangial expansion, and suppressing this signaling pathway may present a novel therapeutic strategy for DN. [ABSTRACT FROM AUTHOR]

Abstract Aims Endothelial dysfunction (ED) plays a pivotal role in the development and progression of cardiovascular disease. Recently, genomic studies have found that ARL15, and some of its common genetic variants are associated with type 2 diabetes and coronary atherosclerosis. Since, the function of ARL15 is unclear we aimed at investigating the role of ARL15 in ED induced by high glucose (HG) in human umbilical vein endothelial cells (HUVECs). Main methods Quantitative real-time PCR was used to access the mRNA expression of ARL15. After exposure to different glucose media, nitric oxide (NO) production and the levels of superoxide dismutase (SOD), malondialdehyde (MDA), and reactive oxygen species (ROS) were studied. The underlying signaling pathway was also examined by western blot. Key findings Up-regulation of ARL15 attenuates HG-induced impairment in HUVECs. With insulin-stimulation, NO production and the active phosphorylation of the IR/IRS1/AKT/eNOS pathway were significantly increased. ARL15 overexpression was found to decrease the ROS and MDA production and increase SOD level. It could also reduce ERK1/2-Thr183-Tyr185 phosphorylation, NOX2 and NOX4 expression in HG medium. Significance These results suggest that ARL15 could significantly alleviate the dysfunction of HUVECs induced by HG. Our findings help to identify new potential protective effects of ARL15 in HG-induced endothelial impairment. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Diabetes mellitus (DM) affects hundreds of million people worldwide and the impaired bone healing is an important DM-related complication. Understanding how DM affects the activities of osteoclasts and the underlying mechanisms is crucial to the development of effective approaches for accelerating bone healing in DM condition. To date, however, the influence of DM on osteoclasts remains obscure and controversial. In this study, we established a type 2 DM (T2DM) alveolar bone defect model, which closely simulates the pathogenesis of human T2DM, to explore the diabetic osteoclast activity during bone regeneration. We found that a high glucose concentration diminished the formation of osteoclasts, and the differentiation and function of osteoclasts from T2DM rats were suppressed. The degradation of matrix by osteoclasts was significantly reduced at a high glucose concentration. In vivo experiments further indicated that T2DM inhibited osteoclastogenesis and osteoclast activity, and delayed the degradation of matrix during the alveolar bone regeneration in T2DM rats. Our work clarifies the influence of T2DM on osteoclasts, and provides valuable insights for the design of novel scaffolding materials that target on osteoclasts for T2DM bone regeneration. Statement of Significance Impaired bone healing is one of the diabetes mellitus (DM)-related complications. Understanding how DM affects osteoclast activity and scaffolding matrix degradation is pivotal to the development of effective approaches for accelerating bone healing in DM condition. Currently, the influences of DM on osteoclast activity and matrix degradation in bone defect areas, however, remain controversial and obscure. Herein, we established a type 2 DM (T2DM) alveolar bone defect model and our results show that T2DM inhibited osteoclastogenesis and osteoclast activity, and delayed the degradation of scaffolding matrix. Our work clarifies the influence of T2DM on osteoclasts and matrix degradation, and provides insights for the design of novel scaffolding materials that target on osteoclasts for T2DM bone regeneration. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Glyoxalase 1 was increased in SH-SY5Y cells exposed to chronic high glucose. • Down-regulation of glyoxalase 1 resulted from inactivation of Nrf2/ARE pathway. • Inactivation of Nrf2/ARE pathway was due to alteration of Nrf2 phosphorylation. • Alteration of p-Nrf2 was involved in PKC activation and/or p38/GSK-3β inhibition. • Quercetin activated Nrf2/ARE pathway by regulating PKC and/or GSK-3β activity. Abstract Although dietary flavonoid quercetin alleviates diabetes-associated cognitive decline in rodents, the mechanisms are not clearly clarified. This study was designed to investigate whether quercetin showed neuroprotection on central neurons against chronic high glucose through the enhancement of Nrf2/ARE/glyoxalase 1 (Glo-1) pathway. SH-SY5Y cells were divided into 8 groups: normal glucose, high glucose (HG), osmotic pressure control, solvent control, HG plus low, middle, high concentrations of quercetin, or Nrf2 activator (sulforaphane). After treatment for 72 h, the associated parameters were measured. We found quercetin and sulforaphane increased cell viability, and enhanced Glo-1 functions (Glo-1 activity, the reduced glutathione and advanced glycation end-products levels) as well as Glo-1 protein and mRNA levels in SH-SY5Y cells cultured with HG. Meanwhile, quercetin and sulforaphane activated Nrf2/ARE pathway, reflected by the raised Nrf2 and p-Nrf2 levels, and the elevated protein and mRNA levels of γ-glutamycysteine synthase (γ-GCS), a known target gene of Nrf2/ARE signaling. Moreover, Nrf2/ARE pathway was activated after pretreatment with a PKC activator, p38 MAPK inhibitor, or GSK-3β inhibitor under the condition of HG, and quercetin addition further strengthened this pathway; however, PKC inhibition or GSK-3β activation pretreatment reversed the effects of quercetin on the protein expression of γ-GCS in the HG condition. In summary, quercetin exerts the neuroprotection by enhancing Glo-1 functions in central neurons under chronic HG condition, which may be mediated by activation of Nrf2/ARE pathway; furthermore, the increased Nrf2 phosphorylation mediated by PKC activation and/or GSK-3β inhibition may involve in the activation of Nrf2/ARE pathway. [ABSTRACT FROM AUTHOR]

Abstract 17β-estradiol (E2) is an important regulator of energy homeostasis and glucose metabolism, thus making it a potential target for preventing or treating metabolic disorders. However, the exact mechanism by which E2 affects high glucose-induced oxidative stress remains unclear. Therefore, the present study investigated the role of E2 in high glucose-induced mitochondrial reactive oxygen species (mtROS) production through estrogen receptor (ER)-mediated signaling in human umbilical cord blood mesenchymal stem cells (hUCB-MSCs) in vitro. In addition, the effect of hUCB-MSC transplantation on mouse skin wound healing induced by E2 in ovariectomized (OVX) diabetic mice in vivo was also studied. High glucose (D -glucose, 25 mM) increased mtROS production, resulting in increase of Beclin1 expression and the LC3-II/LC3-I ratio, leading to decreased cell viability. Conversely, E2 (10 nM) treatment significantly decreased high glucose-induced mtROS levels and subsequently restored cell viability, suggesting that E2 serves as a strong antioxidant. High glucose downregulated Nrf2 levels in nucleus, subsequently culminating in Sirt3 downregulation and manganese superoxide dismutase (MnSOD) acetylation. However, we found that E2 induces nuclear Nrf2 expression via interaction with ERα. The increased nuclear translocation of Nrf2 triggered Sirt3 upregulation and MnSOD activation, both of which play important roles in decreasing mtROS levels. Thus, the therapeutic effect of hUCB-MSC transplantation on skin wound healing in OVX diabetic mice was enhanced by E2 treatment compared with the findings in OVX diabetic mice treated only with hUCB-MSCs. In addition, blood vessels with well-developed branches were observed in OVX diabetic mice that underwent hUCB-MSC transplantation and E2 treatment compared with the effects of ERα siRNA-transfected hUCB-MSC transplantation alone. In conclusion, our results imply that E2 protects cells against high glucose-induced mtROS production and autophagic cell death through increasing nuclear translocation of Nrf2, which was followed by Sirt3 upregulation and MnSOD activation in hUCB-MSCs. Graphical abstract fx1 Highlights • High glucose induces autophagic cell death through mtROS in hUCB-MSCs. • E2 has the protective role on mtROS-induced autophagic cell death in hUCB-MSCs. • E2-induced ERα reduces Nrf2-dependent mtROS levels under high glucose conditions. • E2 enhances Sirt3-dependent MnSOD activation under high glucose conditions. • E2 recovers therapeutic efficacy of hUCB-MSCs via ERα in ovariectomized diabetic mice. [ABSTRACT FROM AUTHOR]

Abstract Aim Inflammation is a driving force in development of atherosclerosis, and hyperglycemia is a significant risk factor for angiopathy. Siglec-9, expressed on human neutrophils and macrophages, engages specific glycan ligands on tissues to diminish ongoing inflammation. Materials and method Siglec-9 ligands on human aorta were characterized and the effects of high glucose exposure on the expression of ligands for Siglec-9 on human umbilical vein endothelial cells (HUV-EC-C) in vitro and ligands for the comparable siglec (Siglec-E) on mouse aorta in vivo were studied. Key findings Siglec-9 ligands were expressed broadly on human aorta, as well as on HUV-EC-C. Siglec-9 ligands on HUV-EC-C were sharply up-regulated under high glucose exposure in vitro, as were Siglec-E ligands on the aortas of hyperglycemic mice. Exposure of HUV-EC-C to high-glucose resulted in consistent inhibitory changes in co-cultured macrophages including increased apoptosis and decreased phagocytosis. Control of Siglec-9 ligand expression on HUV-EC-C was downstream of changes in an enzyme involved in their biosynthesis, UDP-galactose-4-epimerase (GALE) and increased cellular N -acetylgalactosamine. The alteration of GALE was associated with the regulatory microRNA hsa-let-7f. Significance We conclude that exposure to high-glucose results in up-regulation of immune inhibitory Siglec-9 sialoglycan ligands on aorta and HUV-EC-C cells downstream of altered GALE and GalNAc expression, resulting in up-regulation of apoptosis and decrease of phagocytic activity of macrophages. Changes in Siglec-9 sialoglycan ligand expression on vascular endothelial cells may be a natural response to the initial steps of atherosclerosis and might be a potential target to regulate inflammation in diabetic angiopathy. [ABSTRACT FROM AUTHOR]

Highlights • Vildagliptin protects against high glucose- induced cell death. • Vildagliptin suppresses high glucose- induced production of ROS, IL-8 and TNF-α. • Vildagliptin suppresses ICAM-1 and MCP-1, and monocytes adhesion to endothelial cells. • Vildagliptin suppresses TLR-4 expression and NF-κB activation. Abstract Hyperglycemia or high blood sugar is one of the major pathological characteristics of diabetes. The endothelium is the inner layer of the vascular wall and is directly exposed to various stimuli in blood vessels. As a characteristic of diabetes, chronic high glucose is known to be harmful to endothelial cells. In this study, we found that vildagliptin, an available type 2 diabetes agent, protects primary human aortic endothelial cells (HAECs) against damage induced by high glucose. Our data indicate that vildagliptin improves the decrease in endothelial viability and reduces the release of lactate dehydrogenase (LDH) induced by high glucose. Vildagliptin potently suppresses high glucose-induced generation of reactive oxygen species (ROS) and production of vascular inflammatory factors including tumor necrosis factor-α (TNF-α), interleukin-8 (IL-8), intercellular cell adhesion molecule-1 (ICAM-1) and monocyte chemotactic protein 1 (MCP-1). Moreover, vildagliptin suppresses adhesion of monocytes to endothelial cells and induction of toll-like receptor 4 (TLR-4) in HAECs caused by high glucose. Mechanistically, we found that the cellular protective effects mediated by vildagliptin involve suppression of nuclear factor-kappa B (NF-κB) nuclear signals. Collectively, our data indicate that vildagliptin possesses a protective function in vascular cells. [ABSTRACT FROM AUTHOR]

Abstract Background Several miRNAs including miR-21 have emerged as important regulators in the development of diabetic nephropathy (DN). However, the molecular mechanism of miR-21 underlying DN pathogenesis remains to be further discussed. Methods Streptozotocin (STZ)-induced DN rats and high glucose (HG)-induced podocytes were used as the in vivo and in vitro models of DN. miR-21 level was detected by qRT-PCR assay. Inflammatory cytokine levels were assessed by ELISA. Kidney injury of rats was evaluated by blood glucose, serum creatinine and blood urine nitrogen concentrations and periodic acid schiff (PAS) staining. Apoptosis in kidney tissues and podocytes was determined by TUNEL and flow cytometry analyses, respectively. Western blot analysis was applied to measure the protein levels of tissue inhibitors of metalloproteinase 3 (TIMP3), Bax and Bcl-2. The relationship between TIMP3 and miR-21 was confirmed by luciferase reporter assay. Results miR-21 expression was upregulated in serum and kidney tissues of DN patients, kidney tissues of STZ-induced DN rats, and HG-treated podocytes. miR-21 depletion inhibited pro-inflammatory factor (IL-1β, TNF-α) secretions and alleviated kidney damages in STZ-induced DN rats. Moreover, TIMP3 was a target of miR-21 in HG-treated podocytes. Additionally, TIMP3 overexpression abated HG-induced inflammatory responses and podocyte apoptosis. Furthermore, the inhibitory effects of TIMP3 on inflammatory responses and podocyte apoptosis were alleviated by increased miR-21. Conclusion The down-regulation of miR-21 inhibited the progression of DN by targeting TIMP3 in STZ-induced DN rats and HG-treated podocytes, elucidating a novel regulatory mechanism of miR-21 in DN progression and offering a potential target for DN therapy. [ABSTRACT FROM AUTHOR]

[Display omitted] • Tiliroside is identified from Potentilla chinensis. • The protective effect of tiliroside blocks high glucose-induced oxidative stress. • Tiliroside ameliorates accumulation of ECM induced by high glucose. • Activation of Nrf2 mediates the effects of tiliroside in a Keap1-dependent manner. Diabetic nephropathy (DN) is one of the severe microvascular complications of diabetes mellitus and it was proved activation of nuclear factor erythroid 2-related factor 2 (Nrf2) could attenuate DN. To find Nrf2 activators, we explored tiliroside identified from Potentilla chinensis using mesangial cells under high glucose. The results showed tiliroside ameliorated oxidative stress via reducing the overproduction of ROS and MDA as well as enhancing the decreased activity of superoxide dismutase, catalase, and glutathione peroxidase. Meanwhile, tiliroside attenuated the accumulation of extracellular matrix (ECM) including collagen IV, laminin and fibronectin resulting from high glucose through down-regulating transforming growth factor β 1 and connective tissue growth factor. Further investigations revealed activation of Nrf2 by tiliroside was involved in the effects against oxidative stress and accumulation of ECM, and the activation of Nrf2 was dependent on the interaction between Kelch-like ECH-associated protein-1 (Keap1) and tiliroside to disrupt the Keap1-Nrf2 complex. [ABSTRACT FROM AUTHOR]

[Display omitted] One effective strategy for treating atherosclerosis is to inhibit the injury of vascular endothelial cells (VECs) induced by oxidized low-density lipoprotein (oxLDL) and high glucose (HG). This study synthesized and evaluated a series of novel Nrf2 activators derived from the marine natural product phidianidine for their ability to protect human umbilical VECs against oxLDL- and HG-induced injury. The results of in vitro bioassays demonstrated that compound D-36 was the most promising Nrf2 activator, effectively inhibiting the apoptosis of HUVECs induced by oxLDL and HG. Furthermore, Nrf2 knockdown experiments confirmed that compound D-36 protected against oxLDL- and HG-induced apoptosis in HUVECs by activating the Nrf2 pathway. These findings provide important insights into a new chemotype of marine-derived Nrf2 activators that could potentially be optimized to develop effective anti-atherosclerosis agents. [ABSTRACT FROM AUTHOR]

[Display omitted] High dietary glucose consumption and hyperglycemia can result in chronic complications. Several studies suggest that high glucose (HG) induces dysfunction of the intestinal barrier. However, the precise changes remain unclear. In our study, we used in vitro models composed of Caco-2 and/or HT29-MTX cells in both monoculture and co-culture to assess the effects of long-term HG exposure on the morphological, structural, and functional properties of the intestinal barrier. Cells were grown in medium containing normal physiologic glucose (NG, 5.5 mM) or a clinically relevant HG (25 mM) concentration until 21 days. Results demonstrated that HG induced morphological changes, with the layers appearing denser and less organized than under physiological conditions, which is in accordance with the increased migration capacity of Caco-2 cells and proliferation properties of HT29-MTX cells. Although we mostly observed a small decrease in mRNA and protein expressions of three junction proteins (ZO-1, OCLN and E-cad) in both Caco-2 and HT29-MTX cells cultured in HG medium, confocal microscopy showed that HG induced a remarkable reduction in their immunofluorescence intensity, triggering disruption of their associated structural network. In addition, we highlighted that HG affected different functionalities (permeability, mucus production and alkaline phosphatase activity) of monolayers with Caco-2 and HT29-MTX cells. Interestingly, these alterations were stronger in co-culture than in monoculture, suggesting a cross-relationship between enterocytes and goblet cells. Controlling hyperglycemia remains a major therapeutical method for reducing damage to the intestinal barrier and improving therapies. [ABSTRACT FROM AUTHOR]

Mitochondrial dysfunction under diabetic condition leads to the development and progression of neurodegenerative complications. Recently, the beneficial effects of glucagon-like peptide-1 (GLP-1) receptor agonists on diabetic neuropathies have been widely recognized. However, molecular mechanisms underlying the neuroprotective effects of GLP-1 receptor agonists against high glucose (HG)-induced neuronal damages is not completely elucidated. Here, we investigated the underlying mechanisms of GLP-1 receptor agonist treatment against oxidative stress, mitochondrial dysfunction, and neuronal damages under HG conditions mimicking a diabetic hyperglycemic state in SH-SY5Y neuroblastoma cells. We revealed that treatment with exendin-4, a GLP-1 receptor agonist, not only increased the expression of survival markers, phospho-Akt/Akt and Bcl-2, but also decreased the expression of pro-apoptotic marker, Bax, and reduced the levels of reactive oxygen species (ROS) defense markers (catalase, SOD-2, and HO-1) under HG conditions. The expressions of mitochondrial function associated genes, MCU and UCP3, and mitochondrial fission genes, DRP1 and FIS1, were decreased by exendin-4 compared to non-treated levels, while the protein expression levels of mitochondrial homeostasis regulators, Parkin and PINK1, were enhanced. In addition, blockade of Epac and Akt activities was able to antagonize these neuroprotective effects of exendin-4. Collectively, we demonstrated that stimulation of GLP-1 receptor propagates a neuroprotective cascade against the oxidative stress and mitochondrial dysfunction as well as augments survival through the Epac/Akt-dependent pathway. Therefore, the revealed mechanisms underlying GLP-1 receptor pathway by preserving mitochondrial homeostasis would be a therapeutic candidate to alleviate neuronal dysfunctions and delay the progression of diabetic neuropathies. [Display omitted] • Neuroprotective effects of exendin-4 occurred through GLP-1R/Epac/Akt signaling. • Exendin-4 induced survival (p-Akt; Bcl-2) and decreased pro-apoptotic (Bax) markers. • Exendin-4 decreased mitochondrial indicators (MCU; UCP3; DRP1; FIS1). • Mitochondrial homeostasis regulators (Parkin; PINK1) were enhanced by exendin-4. [ABSTRACT FROM AUTHOR]