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Diabetic nephropathy (DN) has been recognized as a severe complication of diabetes mellitus and a dominant pathogeny of end-stage kidney disease, which causes serious health problems and great financial burden to human society worldwide. Conventional strategies, such as renin-angiotensin-aldosterone system blockade, blood glucose level control, and bodyweight reduction, may not achieve satisfactory outcomes in many clinical practices for DN management. Notably, due to the multi-target function, Chinese medicine possesses promising clinical benefits as primary or alternative therapies for DN treatment. Increasing studies have emphasized identifying bioactive compounds and molecular mechanisms of reno-protective effects of Chinese medicines. Signaling pathways involved in glucose/lipid metabolism regulation, antioxidation, anti-inflammation, anti-fibrosis, and podocyte protection have been identified as crucial mechanisms of action. Herein, we summarize the clinical efficacies of Chinese medicines and their bioactive components in treating and managing DN after reviewing the results demonstrated in clinical trials, systematic reviews, and meta-analyses, with a thorough discussion on the relative underlying mechanisms and molecular targets reported in animal and cellular experiments. We aim to provide comprehensive insights into the protective effects of Chinese medicines against DN., Graphical abstract Diabetic nephropathy is one of the most severe complications of diabetes mellitus. Chinese medicines have been intensively studied in treating diabetic nephropathy. This review comprehensively summarizes and discusses the clinical efficacies and underlying mechanisms of Chinese medicines for diabetic nephropathy, providing deep insights and profound perspectives into this field.Image 1

Highlights • The cellular activity of USPs is functionally implicated in cancer progression. • USP8 negatively regulates the TRAF6-mediated signals for NF-κB and autophagy. • USP8KO SK-HEP-1 cells reveal increases of cancer progression in vivo and in vitro. • TCGA and transcriptome data support the functional role of USP8 in liver cancers., Herein, we aimed to elucidate the molecular and cellular mechanism in which ubiquitin-specific protease 8 (USP8) is implicated in liver cancer progression via TRAF6-mediated signal. USP8 induces the deubiquitination of TRAF6, TAB2, TAK1, p62, and BECN1, which are pivotal roles for NF-κB activation and autophagy induction. Notably, the LIHC patient with low USP8 mRNA expression showed markedly shorter survival time, whereas there was no significant difference in the other 18-human cancers. Importantly, the TCGA data analysis on LIHC and transcriptome analysis on the USP8 knockout (USP8KO) SK-HEP-1 cells revealed a significant correlation between USP8 and TRAF6, TAB2, TAK1, p62, and BECN1, and enhanced NF-κB-dependent and autophagy-related cancer progression/metastasis-related genes in response to LPS stimulation. Furthermore, USP8KO SK-HEP-1 cells showed an increase in cancer migration and invasion by TLR4 stimulation, and a marked increase of tumorigenicity and metastasis in xenografted NSG mice. The results demonstrate that USP8 is negatively implicated in the LIHC progression through the regulation of TRAF6-mediated signal for the activation of NF-κB activation and autophagy induction. Our findings provide useful insight into the LIHC pathogenesis of cancer progression.

Type 2 diabetes mellitus, obesity, hypertension, and other associated metabolic complications have been demonstrated as a crucial contributor to the enhanced morbidity and mortality of patients with coronavirus disease 2019 (COVID-19). Data on the interplay between metabolic comorbidities and the outcomes in patients with COVID-19 have been emerging and rapidly increasing. This implies a mechanistic link between metabolic diseases and COVID-19 resulting in the exacerbation of the condition. Nonetheless, new evidences are emerging to support insulin-mediated aggressive glucose-lowering treatment as a possible trigger of high mortality rate in diabetic COVID-19 patients, putting the clinician in a confounding and difficult dilemma for the treatment of COVID-19 patients with metabolic comorbidities. Thus, this review discusses the pathophysiological link among severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), angiotensin-converting enzyme 2 (ACE2), metabolic complications, and severe inflammation in COVID-19 development, especially in those with multi-organ injuries. We discuss the influence of several routinely used drugs in COVID-19 patients, including anti-inflammatory and anti-coagulant drugs, antidiabetic drugs, renin-angiotensin-aldosterone system inhibitors. Especially, we provide a balanced overview on the clinical application of glucose-lowering drugs (insulin and metformin), angiotensin-converting-enzyme inhibitors, and angiotensin receptor blockers. Although there is insufficient evidence from clinical or basic research to comprehensively reveal the mechanistic link between adverse outcomes in COVID-19 and metabolic comorbidities, it is hoped that the update in the current review may help to better outline the optimal strategies for clinical management of COVID-19 patients with metabolic comorbidities.

Oxidative stress and inflammation interact in the development of diabetic atherosclerosis. Intracellular hyperglycemia promotes production of mitochondrial reactive oxygen species (ROS), increased formation of intracellular advanced glycation end-products, activation of protein kinase C, and increased polyol pathway flux. ROS directly increase the expression of inflammatory and adhesion factors, formation of oxidized-low density lipoprotein, and insulin resistance. They activate the ubiquitin pathway, inhibit the activation of AMP-protein kinase and adiponectin, decrease endothelial nitric oxide synthase activity, all of which accelerate atherosclerosis. Changes in the composition of the gut microbiota and changes in microRNA expression that influence the regulation of target genes that occur in diabetes interact with increased ROS and inflammation to promote atherosclerosis. This review highlights the consequences of the sustained increase of ROS production and inflammation that influence the acceleration of atherosclerosis by diabetes. The potential contributions of changes in the gut microbiota and microRNA expression are discussed. Keywords: Atherosclerosis, Diabetes mellitus, Reactive oxygen species, Gut microbiota, MicroRNA

Hemodialysis vascular access dysfunction is a common and intractable problem in clinical practice with no definitive therapy yet available. As a key mediator of vascular and cardiac maladaptive remodeling, mineralocorticoid receptor (MR) plays a pivotal role in vascular fibrosis and intimal hyperplasia (IH) and is potentiated locally in hemodialysis vascular access following diverse injuries, like barotrauma, cannulation and shear stress. MR-related genomic and non-genomic pathways are responsible for triggering vascular smooth muscle cell activation, proliferation, migration and extracellular matrix overproduction. In endothelial cells, MR signaling diminishes nitric oxide production and its bioavailability, but amplifies reactive oxygen species, leading to an inflammatory state. Moreover, MR favors macrophage polarization towards a pro-inflammatory phenotype. In clinical settings like post-angioplasty or stenting restenosis, the beneficial effect of MR antagonists on vascular fibrosis and IH has been validated. In aggregate, therapeutic targeting of MR may provide a new avenue to prevent hemodialysis vascular access dysfunction., Highlights • MR signaling is instrumental in both insufficient outward remodeling and exuberant inward remodeling of AVF. • The effects of MR in VSMC, endothelial cell, and macrophage act synergistically to promote IH and vascular fibrosis in AVF. • Pharmacological targeting of MR represents a novel therapeutic strategy to prevent hemodialysis vascular access dysfunction.

Cigarette smoke is a known risk factor for inflammatory diseases in the respiratory tract, and inflammatory exacerbation is considered pivotal to the pathogenesis of these diseases. Here, we performed two repeated exposure studies in which we exposed human bronchial epithelial tissues in an organotypic culture model to cigarette smoke extract (CSE); the first study was conducted over a four-day period to determine the suitable dose range for the extended exposure period, and the second was a one-month exposure study to elucidate the exposure-by-exposure effects in bronchial tissues. We focused on matrix metalloproteinase (MMP)-9 and -1/3 and the inflammatory cytokines interleukin (IL)-8 and growth factor related oncogene to evaluate the transition into an inflammatory state. Even at CSE doses with no or low toxicity for a single exposure, the repetition of exposure induced cumulative effects on both the inflammatory responses, specifically the IL-8 and MMPs levels, and tissue morphology. Interestingly, untreated controls initially had relatively high baseline levels of these secreted proteins; these levels gradually declined, after which they showed periodic level changes, suggesting an acclimation period may be needed for this system. These results demonstrate the usability of this system for the elucidation of sub-chronic effects in vitro. Keywords: Cigarette smoke extract, Repeated exposure, Organotypic culture

Background & Aims Nonalcoholic steatohepatitis (NASH) is associated with oxidative stress. We surmised that pharmacologic activation of NF-E2 p45-related factor 2 (Nrf2) using the acetylenic tricyclic bis(cyano enone) TBE-31 would suppress NASH because Nrf2 is a transcriptional master regulator of intracellular redox homeostasis. Methods Nrf2+/+ and Nrf2-/- C57BL/6 mice were fed a high-fat plus fructose (HFFr) or regular chow diet for 16 weeks or 30 weeks, and then treated for the final 6 weeks, while still being fed the same HFFr or regular chow diets, with either TBE-31 or dimethyl sulfoxide vehicle control. Measures of whole-body glucose homeostasis, histologic assessment of liver, and biochemical and molecular measurements of steatosis, endoplasmic reticulum (ER) stress, inflammation, apoptosis, fibrosis, and oxidative stress were performed in livers from these animals. Results TBE-31 treatment reversed insulin resistance in HFFr-fed wild-type mice, but not in HFFr-fed Nrf2-null mice. TBE-31 treatment of HFFr-fed wild-type mice substantially decreased liver steatosis and expression of lipid synthesis genes, while increasing hepatic expression of fatty acid oxidation and lipoprotein assembly genes. Also, TBE-31 treatment decreased ER stress, expression of inflammation genes, and markers of apoptosis, fibrosis, and oxidative stress in the livers of HFFr-fed wild-type mice. By comparison, TBE-31 did not decrease steatosis, ER stress, lipogenesis, inflammation, fibrosis, or oxidative stress in livers of HFFr-fed Nrf2-null mice. Conclusions Pharmacologic activation of Nrf2 in mice that had already been rendered obese and insulin resistant reversed insulin resistance, suppressed hepatic steatosis, and mitigated against NASH and liver fibrosis, effects that we principally attribute to inhibition of ER, inflammatory, and oxidative stress., Graphical abstract

Atherosclerosis and its complications are responsible for one in three global deaths. Nutraceuticals show promise in the prevention and treatment of atherosclerosis but require an indepth understanding of the mechanisms underlying their actions. A previous study showed that the omega-6 fatty acid, dihomo-γ-linolenic acid (DGLA), attenuated atherosclerosis in the apolipoprotein E deficient mouse model system. However, the mechanisms underlying such protective effects of DGLA are poorly understood and were therefore investigated. We show that DGLA attenuates chemokine-driven monocytic migration together with foam cell formation and the expression of key pro-atherogenic genes induced by three pro-inflammatory cytokines in human macrophages. The effect of DGLA on interferon-γ signaling was mediated via inhibition of signal transducer and activator of transcription-1 phosphorylation on serine 727. In relation to anti-foam cell action, DGLA inhibits modified LDL uptake by both macropinocytosis and receptor-mediated endocytosis, the latter by reduction in expression of two key scavenger receptors (SR-A and CD36), and stimulates cholesterol efflux from foam cells. DGLA also improves macrophage mitochondrial bioenergetic profile by decreasing proton leak. Gamma-linolenic acid and prostaglandin E1, upstream precursor and key metabolite respectively of DGLA, also acted in an anti-atherogenic manner. The actions of DGLA extended to other key atherosclerosis-associated cell types with attenuation of endothelial cell proliferation and migration of smooth muscle cells in response to platelet-derived growth factor. This study provides novel insights into the molecular mechanisms underlying the anti-atherogenic actions of DGLA and supports further assessments on its protective effects on plaque regression in vivo and in human trials., Highlights • Dihomo-γ-linolenic acid (DGLA) attenuates atherosclerosis in a mouse model system. • The mechanisms underlying anti-atherogenic actions of DGLA are poorly understood. • DGLA inhibited atherogenic processes in three key cell types in this disease. • Mechanisms underlying such protective actions of DGLA were identified. • Studies inform on the beneficial anti-atherogenic actions of DGLA.

Background & Aims Toll-like receptor 2 (TLR2) and TLR3 regulate hepatic immunity under pathological conditions, but their functions and potential drug targets in alcoholic liver disease (ALD) remain poorly understood. Methods ALD-associated liver injury were induced in TLR2 knockout (TLR2–/–), TLR3–/–, TLR2–/– bone marrow transplanted (BMT), TLR3–/– BMT, IL-10–/– mice, and their wild-type littermates through ethanol challenge with or without co-administered epigallocatechin-3-gallate (EGCG). Moreover, Kupffer cells were depleted by GdCl3 injection to evaluate their pathogenic roles in ALD. Results We identified that deficiency of TLR2 and TLR3 significantly alleviated and aggravated ALD-induced liver injury, respectively. Mechanistically, Kupffer cell inactivation, M1 to M2 polarization, and IL-10 production via STAT3 activation contributed to hepatic protection mediated by concurrent TLR2 inhibition and TLR3 agonism. These findings were further confirmed in TLR2 and TLR3 BMT mice. We also identified a novel ALD-protective agent EGCG which directly interacted with Kupffer cell TLR2/3 to induce IL-10 production. Deficiency of IL-10 aggravated ALD injury and blunted EGCG-mediated hepatoprotection while depletion of Kupffer cells partially recovered liver injury but abolished EGCG’s actions. Conclusions Altogether, our results illustrate the divergent roles of Kupffer cells TLR2/3 in ALD progression via anti-inflammatory cytokine IL-10 production., Graphical abstract

Cholangiocarcinoma (CCA) is an aggressive and multifactorial malignancy of the biliary tract. The carcinogenesis of CCA is associated with genomic and epigenetic abnormalities, as well as environmental effects. However, early clinical diagnosis and reliable treatment strategies of CCA remain unsatisfactory. Multiple compartments of the tumor microenvironment significantly affect the progression of CCA. Tumor-associated macrophages (TAMs) are a type of plastic immune cells that are recruited and activated in the CCA microenvironment, especially at the tumor invasive front and perivascular sites. TAMs create a favorable environment that benefits CCA growth by closely interacting with CCA cells and other stromal cells via releasing multiple protumor factors. In addition, TAMs exert immunosuppressive and antichemotherapeutic effects, thus intensifying the malignancy. Targeting TAMs may provide an improved understanding of, and novel therapeutic approaches for, CCA. This review focuses on revealing the interplay between TAMs and CCA.

Objective: Insulin resistance can be triggered by enhanced dephosphorylation of the insulin receptor or downstream components in the insulin signaling cascade through protein tyrosine phosphatases (PTPs). Downregulating density-enhanced phosphatase-1 (DEP-1) resulted in an improved metabolic status in previous analyses. This phenotype was primarily caused by hepatic DEP-1 reduction. Methods: Here we further elucidated the role of DEP-1 in glucose homeostasis by employing a conventional knockout model to explore the specific contribution of DEP-1 in metabolic tissues. Ptprj−/− (DEP-1 deficient) and wild-type C57BL/6 mice were fed a low-fat or high-fat diet. Metabolic phenotyping was combined with analyses of phosphorylation patterns of insulin signaling components. Additionally, experiments with skeletal muscle cells and muscle tissue were performed to assess the role of DEP-1 for glucose uptake. Results: High-fat diet fed-Ptprj−/− mice displayed enhanced insulin sensitivity and improved glucose tolerance. Furthermore, leptin levels and blood pressure were reduced in Ptprj−/− mice. DEP-1 deficiency resulted in increased phosphorylation of components of the insulin signaling cascade in liver, skeletal muscle and adipose tissue after insulin challenge. The beneficial effect on glucose homeostasis in vivo was corroborated by increased glucose uptake in skeletal muscle cells in which DEP-1 was downregulated, and in skeletal muscle of Ptprj−/− mice. Conclusion: Together, these data establish DEP-1 as novel negative regulator of insulin signaling.

It has been widely reported that T cells are capable of influencing osteoclast formation and bone remodelling, yet relatively little is known of the reciprocal effects of osteoclasts for affecting T cell function and/or activity. In this study we investigated the effects of human osteoclasts on the function of γδ T cells, a subset of non-CD4+ T cells implicated in a variety of inflammatory disease states. γδ T cells and CD4+ T cells were isolated from peripheral blood of healthy volunteers and were co-cultured with autologous mature osteoclasts (generated by treatment with M-CSF and RANKL) before phenotypical and functional changes in the T cell populations were assessed. Macrophages, osteoclasts, and conditioned medium derived from macrophages or osteoclasts induced activation of γδ T cells, as determined by the expression of the early activation marker CD69. TNFα was a major mediator of this stimulatory effect on γδ T cells. Consistent with this stimulatory effect, osteoclasts augmented proliferation of IL-2-stimulated γδ T cells and also supported the survival of unstimulated γδ and CD4+ T cells, although these effects required co-culture with osteoclasts. Co-culture with osteoclasts also increased the proportion of γδ T cells producing IFNγ, but did not modulate IFNγ or IL-17 production by CD4+ T cells. We provide new insights into the in vitro interactions between human γδ T cells and osteoclasts/macrophages, and demonstrate that osteoclasts or their precursors are capable of influencing γδ T function both via the release of soluble factors and also through direct cell–cell interactions., Highlights • Interactions of human macrophages and osteoclasts with γδ T cells were investigated. • Osteoclasts produce T cell-active chemokines and stimulate γδ T cell migration. • Osteoclasts induced activation of autologous γδ T cells via TNFα. • Osteoclasts promoted γδ T cell survival and augmented γδ T cell proliferation. • Macrophages and osteoclasts stimulate IFNγ production in γδ T cells.

High-fat diet (HFD) and inflammation are the key contributors to insulin resistance and type 2 diabetes (T2D). Previous study shows fatty acid-induced accumulation of damaged, reactive oxygen species (ROS)-generating mitochondria, and this in turn activates the NLRP3 inflammasome interference with insulin signaling. Our previous research shows NLRP3 inflammasome activation signal originates from defects in autophagy. Yet how the fatty acid related to mitophagy alteration leads to the activation of NLRP3-ASC inflammasome has not been considered. Here we demonstrated that palmitate (PA) induced mitophagy deficiency, leading to damaged mitochondrion as characterized by mito-ROS production and loss of membrane potential. Antioxidant APDC or Ca2+ signaling inhibitor Nifedipine blocked PA-induced NLRP3 inflammasome activation. Further, we provided evidences that PA reduced the expression of Ras homolog enriched in brain (Rheb) and disrupted Rheb recruitment to the mitochondrial outer membrane. In addition, sustained PA caused disassociation of kinesin family member 5B (KIF5B) from binding with mitochondria via Ca2+-dependent effects. Disruption of Rheb and KIF5B interaction with mitochondria blocked mitochondrial degradation along with IL-1β dependent insulin resistance, which was majorly attenuated by Rheb/KIF5B overexpression. In a consequence, defective mitophagy led to the accumulation of damaged-ROS-generating mitochondria, down pathway of NLRP3-ASC-Caspase 1 activation, and subsequently, insulin resistance. These findings provide insights into the association of inflammation, mitophagy and T2D., Highlights • PA induced disruption of KIF5B-mediated mitochondrial motility and loss of Rheb-dependent mitophagy. • Defective mitophagy led to NLRP3-ASC-Caspase 1 activation, and subsequently, insulin resistance. • Antioxidant APDC or Ca2+ signaling inhibitor nifidipine blocked PA-induced NLRP3 inflammasome activation., Graphical abstract

Systemic deletion of the gene encoding for adipose triglyceride lipase (ATGL) in mice leads to severe cardiac dysfunction due to massive accumulation of neutral lipids in cardiomyocytes. Recently, impaired peroxisome proliferator-activated receptor α (PPARα) signaling has been described to substantially contribute to the observed cardiac phenotype. Disturbances of the ubiquitin–proteasome system (UPS) have been implicated in numerous cardiac diseases including cardiomyopathy, ischemic heart disease, and heart failure. The objective of the present study was to investigate the potential role of UPS in cardiac ATGL deficiency. Our results demonstrate prominent accumulation of ubiquitinated proteins in hearts of ATGL-deficient mice, an effect that was abolished upon cardiomyocyte-directed overexpression of ATGL. In parallel, cardiac protein expression of the ubiquitin-activating enzyme E1a, which catalyzes the first step of the ubiquitination cascade, was significantly upregulated in ATGL-deficient hearts. Dysfunction of the UPS was accompanied by activation of NF-κB signaling. Moreover, the endoplasmic reticulum (ER)-resident chaperon protein disulfide isomerase was significantly upregulated in ATGL-deficient hearts. Chronic treatment of ATGL-deficient mice with the PPARα agonist Wy14,643 improved proteasomal function, prevented NF-κB activation and decreased oxidative stress. In summary, our data point to a hitherto unrecognized link between proteasomal function, PPARα signaling and cardiovascular disease., Highlights • Accumulation of ubiquitinated proteins was increased in ATGL-deficient hearts. • Cardiac NF-κB signaling was upregulated in ATGL deficiency. • Chronic PPARα treatment improved proteasomal function. • Cardiac NOX activity was normalized upon PPARα treatment.

Cardiac oxidative stress has been implicated in the pathogenesis of hypertrophy, cardiomyopathy and heart failure. Systemic deletion of the gene encoding adipose triglyceride lipase (ATGL), the enzyme that catalyzes the rate-limiting step of triglyceride lipolysis, results in a phenotype characterized by severe steatotic cardiac dysfunction. The objective of the present study was to investigate a potential role of oxidative stress in cardiac ATGL deficiency. Hearts of mice with global ATGL knockout were compared to those of mice with cardiomyocyte-restricted overexpression of ATGL and to those of wildtype littermates. Our results demonstrate that oxidative stress, measured as lucigenin chemiluminescence, was increased ~ 6-fold in ATGL-deficient hearts. In parallel, cytosolic NADPH oxidase subunits p67phox and p47phox were upregulated 4–5-fold at the protein level. Moreover, a prominent upregulation of different inflammatory markers (tumor necrosis factor α, monocyte chemotactant protein-1, interleukin 6, and galectin-3) was observed in those hearts. Both the oxidative and inflammatory responses were abolished upon cardiomyocyte-restricted overexpression of ATGL. Investigating the effect of oxidative and inflammatory stress on nitric oxide/cGMP signal transduction we observed a ~ 2.5-fold upregulation of soluble guanylate cyclase activity and a ~ 2-fold increase in cardiac tetrahydrobiopterin levels. Systemic treatment of ATGL-deficient mice with the superoxide dismutase mimetic Mn(III)tetrakis (4-benzoic acid) porphyrin did not ameliorate but rather aggravated cardiac oxidative stress. Our data suggest that oxidative and inflammatory stress seems involved in lipotoxic heart disease. Upregulation of soluble guanylate cyclase and cardiac tetrahydrobiopterin might be regarded as counterregulatory mechanisms in cardiac ATGL deficiency., Graphical abstract, Highlights • ATGL(−/−) mice suffer from severe cardiac oxidative stress originating from upregulation of NOX2-dependent NADPH oxidase. • Inflammation markers TNFα, MCP-1, IL-6, and Mac-2 are increased in cardiac ATGL deficiency. • Activity of sGC and cardiac BH4 levels are elevated in ATGL(−/−) hearts. • Systemic treatment of ATGL(−/−) mice with the SOD mimetic MnTBAP did not ameliorate oxidative stress.

COPD (chronic obstructive pulmonary disease) is a major incurable global health burden and will become the third largest cause of death in the world by 2020. It is currently believed that an exaggerated inflammatory response to inhaled irritants, in particular cigarette smoke, causes progressive airflow limitation. This inflammation, where macrophages, neutrophils and T-cells are prominent, leads to oxidative stress, emphysema, small airways fibrosis and mucus hypersecretion. The mechanisms and mediators that drive the induction and progression of chronic inflammation, emphysema and altered lung function are poorly understood. Current treatments have limited efficacy in inhibiting chronic inflammation, do not reverse the pathology of disease and fail to modify the factors that initiate and drive the long-term progression of disease. Therefore there is a clear need for new therapies that can prevent the induction and progression of COPD. Animal modelling systems that accurately reflect disease pathophysiology continue to be essential to the development of new therapies. The present review highlights some of the mouse models used to define the cellular, molecular and pathological consequences of cigarette smoke exposure and whether they can be used to predict the efficacy of new therapeutics for COPD.

Pathological accumulation of 27-carbon intermediates or end-products of cholesterol metabolism, named oxysterols, may contribute to the onset and especially to the development of major chronic diseases in which inflammation, but also oxidative damage and to a certain extent cell death, are hallmarks and primary mechanisms of progression. Indeed, certain oxysterols exercise strong pro-oxidant and pro-inflammatory effects at concentrations detectable in the lesions typical of atherosclerosis, neurodegenerative diseases, inflammatory bowel diseases, age-related macular degeneration, and other pathological conditions characterized by altered cholesterol uptake and/or metabolism., Graphical Abstract AAA Research highlights ► Oxysterols are 27-carbon-atom products of enzymatic or non-enzymatic oxidation of cholesterol. ► Oxidative stress is the major non-enzymatic source of oxysterols. ► Oxysterols may in turn amplify oxidative redox imbalance in cells and tissues. ► Pathological accumulation of oxysterols triggers and sustains inflammatory reactions. ► Oxysterol-mediated inflammation is a primary mechanism of progression in major chronic diseases.

Sirtuins are members of the Sir2 (silent information regulator 2) family, a group of class III deacetylases. Mammals have seven different sirtuins, SIRT1–SIRT7. Among them, SIRT1, SIRT3 and SIRT6 are induced by calorie restriction conditions and are considered anti-aging molecules. SIRT1 has been the most extensively studied. SIRT1 deacetylates target proteins using the coenzyme NAD+ and is therefore linked to cellular energy metabolism and the redox state through multiple signalling and survival pathways. SIRT1 deficiency under various stress conditions, such as metabolic or oxidative stress or hypoxia, is implicated in the pathophysiologies of age-related diseases including diabetes, cardiovascular diseases, neurodegenerative disorders and renal diseases. In the kidneys, SIRT1 may inhibit renal cell apoptosis, inflammation and fibrosis, and may regulate lipid metabolism, autophagy, blood pressure and sodium balance. Therefore the activation of SIRT1 in the kidney may be a new therapeutic target to increase resistance to many causal factors in the development of renal diseases, including diabetic nephropathy. In addition, SIRT3 and SIRT6 are implicated in age-related disorders or longevity. In the present review, we discuss the protective functions of sirtuins and the association of sirtuins with the pathophysiology of renal diseases, including diabetic nephropathy.

Dietary recommendations suggest decreased consumption of SFA to minimise CVD risk; however, not all foods rich in SFA are equivalent. To evaluate the effects of SFA in a dairy food matrix, as Cheddar cheese, v. SFA from a vegan-alternative test meal on postprandial inflammatory markers, a randomised controlled cross-over trial was conducted in twenty overweight or obese adults with metabolic abnormalities. Individuals consumed two isoenergetic high-fat mixed meals separated by a 1- to 2-week washout period. Serum was collected at baseline, and at 1, 3 and 6 h postprandially and analysed for inflammatory markers (IL-6, IL-8, IL-10, IL-17, IL-18, TNFα, monocyte chemotactic protein-1 (MCP-1)), acute-phase proteins C-reactive protein (CRP) and serum amyloid-A (SAA), cellular adhesion molecules and blood lipids, glucose and insulin. Following both high-fat test meals, postprandial TAG concentrations rose steadily (P < 0·05) without a decrease by 6 h. The incremental AUC (iAUC) for CRP was significantly lower (P < 0·05) in response to the cheese compared with the vegan-alternative test meal. A treatment effect was not observed for any other inflammatory markers; however, for both test meals, multiple markers significantly changed from baseline over the 6 h postprandial period (IL-6, IL-8, IL-18, TNFα, MCP-1, SAA). Saturated fat in the form of a cheese matrix reduced the iAUC for CRP compared with a vegan-alternative test meal during the postprandial 6 h period. The study is registered at clinicaltrials.gov under NCT01803633.

The atherogenic cytokine IL-6 (interleukin-6) induces pro-inflammatory gene expression in VECs (vascular endothelial cells) by activating the JAK (Janus kinase)/STAT3 (signal transducer and activator of transcription 3) signalling pathway, which is normally down-regulated by the STAT3-dependent induction of the E3 ubiquitin ligase component SOCS3 (suppressor of cytokine signalling 3). Novel treatments based on the regulation of SOCS3 protein levels could therefore have value in the treatment of diseases with an inflammatory component, such as atherosclerosis. To this end we carried out a screen of 1031 existing medicinal compounds to identify inducers of SOCS3 gene expression and identified the flavanoids naringenin and flavone as effective inducers of SOCS3 protein, mRNA and promoter activity. This was in contrast with the action of traditional JAK/STAT3 inhibitors and the polyphenol resveratrol, which effectively suppress SOCS3 gene expression. Both naringenin and flavone also effectively suppressed IL-6-stimulated phosphorylation of STAT3 (Tyr705) which led to suppression of IL-6-induction of the atherogenic STAT3 target gene MCP1 (monocyte chemotactic protein-1), suggesting that their ability to induce SOCS3 gene expression is STAT3-independent. Supporting this idea was the observation that the general kinase inhibitor compound C inhibits flavone- and cAMP-dependent, but not JAK-dependent, SOCS3 induction in VECs. Indeed, the ability of flavanoids to induce SOCS3 expression requires activation of the ERK (extracellular-signal-regulated kinase)-dependent transcription factor SP3, and not STAT3. In the present paper we therefore describe novel molecular actions of flavanoids, which control SOCS3 gene induction and suppression of STAT3 signalling in VECs. These mechanisms could potentially be exploited to develop novel anti-atherogenic therapies.

Dietary strategies for alleviating health complications associated with type 2 diabetes (T2D) are being pursued as alternatives to pharmaceutical interventions. Berries such as bilberries (Vaccinium myrtillus L.) that are rich in polyphenols may influence carbohydrate digestion and absorption and thus postprandial glycaemia. In addition, berries have been reported to alter incretins as well as to have antioxidant and anti-inflammatory properties that may also affect postprandial glycaemia. The present study investigated the acute effect of a standardised bilberry extract on glucose metabolism in T2D. Male volunteers with T2D (n 8; BMI 30 (sd 4) kg/m2) controlling their diabetes by diet and lifestyle alone were given a single oral capsule of either 0·47 g standardised bilberry extract (36 % (w/w) anthocyanins) which equates to about 50 g of fresh bilberries or placebo followed by a polysaccharide drink (equivalent to 75 g glucose) in a double-blinded cross-over intervention with a 2-week washout period. The ingestion of the bilberry extract resulted in a significant decrease in the incremental AUC for both glucose (P = 0·003) and insulin (P = 0·03) compared with the placebo. There was no change in the gut (glucagon-like peptide-1, gastric inhibitory polypeptide), pancreatic (glucagon, amylin) or anti-inflammatory (monocyte chemotactic protein-1) peptides. In addition there was no change in the antioxidant (Trolox equivalent antioxidant capacity, ferric-reducing ability of plasma) responses measured between the volunteers receiving the bilberry extract and the placebo. In conclusion the present study demonstrates for the first time that the ingestion of a concentrated bilberry extract reduces postprandial glycaemia and insulin in volunteers with T2D. The most likely mechanism for the lower glycaemic response involves reduced rates of carbohydrate digestion and/or absorption.

Exposure to EMFs (electromagnetic fields) results in a number of important biological changes, including modification of genetic expression. We have investigated the effect of 60 Hz sinusoidal EMFs at a magnetic flux density of 80 μT on the expression of the luciferase gene contained in a plasmid labelled as pEMF (EMF plasmid). This gene construct contains the specific sequences for the induction of hsp70 (heat-shock protein 70) expression by EMFs, as well as the reporter for the luciferase gene. The pEMF vector was electrotransferred into quadriceps muscles of BALB/c mice that were later exposed to EMFs. Increased luciferase expression was observed in mice exposed to EMFs 2 h daily for 7 days compared with controls (P

Systemic knockout of adipose triglyceride lipase (ATGL), the pivotal enzyme of triglyceride lipolysis, results in a murine phenotype that is characterized by progredient cardiac steatosis and severe heart failure. Since cardiac and vascular dysfunction have been closely related in numerous studies we investigated endothelium-dependent and -independent vessel function of ATGL knockout mice. Aortic relaxation studies and Langendorff perfusion experiments of isolated hearts showed that ATGL knockout mice suffer from pronounced micro- and macrovascular endothelial dysfunction. Experiments with agonists directly targeting vascular smooth muscle cells revealed the functional integrity of the smooth muscle cell layer. Loss of vascular reactivity was restored ~ 50% upon treatment of ATGL knockout mice with the PPARα agonist Wy14,643, indicating that this phenomenon is partly a consequence of impaired cardiac contractility. Biochemical analysis revealed that aortic endothelial NO synthase expression and activity were significantly reduced in ATGL deficiency. Enzyme activity was fully restored in ATGL mice treated with the PPARα agonist. Biochemical analysis of perivascular adipose tissue demonstrated that ATGL knockout mice suffer from perivascular inflammatory oxidative stress which occurs independent of cardiac dysfunction and might contribute to vascular defects. Our results reveal a hitherto unrecognized link between disturbed lipid metabolism, obesity and cardiovascular disease., Graphical abstract, Highlights • AKO mice suffer from severe micro- and macrovascular endothelial dysfunction. • Aortic eNOS protein is downregulated in ATGL deficiency due to enhanced proteasomal degradation. • PVAT of AKO mice exhibits characteristics of chronic inflammatory oxidative stress. • At least two independent mechanisms are involved in the endothelial defect.

Nonalcoholic fatty liver disease (NAFLD) is becoming a public health problem worldwide. A subset of patients develop an inflammatory disease, nonalcoholic steatohepatitis (NASH), characterized by steatosis, hepatocellular death, macrophage and neutrophil accumulation, and varying stages of fibrosis. Hepatocyte cell death triggers the cellular inflammatory response, therefore reducing cell death may be salutary in the steatohepatitis disease process. Recently, a better understanding of hepatocyte apoptosis in NASH has been obtained and new information regarding other cell death modes such as necroptosis and pyroptosis has been reported. Hepatocyte lipotoxicity is often triggered by death receptors. In addition to causing apoptosis, death receptors have been shown to mediate proinflammatory signaling, suggesting that apoptosis in this context is not an immunologically silent process. Here, we review recent developments in our understanding of hepatocyte cell death by death receptors and its mechanistic link to inflammation in NASH. We emphasize how proapoptotic signaling by death receptors may induce the release of proinflammatory extracellular vesicles, thereby recruiting and activating macrophages and promoting the steatohepatitis process. Potential therapeutic strategies are discussed based on this evolving information. Keywords: Apoptosis, Caspase Inhibitor, Cell Death, Death Receptors, Exosomes, Extracellular Vesicles, Fibrosis, Inflammation, Inflammasome, Microvesicles, Necroptosis, Pyroptosis

The Western meat-rich diet is both high in protein and fat. Although the hazardous effect of a high fat diet (HFD) upon liver structure and function is well recognized, whether the co-presence of high protein intake contributes to, or protects against, HF-induced hepatic injury remains unclear. Increased intake of branched chain amino acids (BCAA, essential amino acids compromising 20% of total protein intake) reduces body weight. However, elevated circulating BCAA is associated with non-alcoholic fatty liver disease and injury. The mechanisms responsible for this quandary remain unknown; the role of BCAA in HF-induced liver injury is unclear. Utilizing HFD or HFD + BCAA models, we demonstrated BCAA supplementation attenuated HFD-induced weight gain, decreased fat mass, activated mammalian target of rapamycin (mTOR), inhibited hepatic lipogenic enzymes, and reduced hepatic triglyceride content. However, BCAA caused significant hepatic damage in HFD mice, evidenced by exacerbated hepatic oxidative stress, increased hepatic apoptosis, and elevated circulation hepatic enzymes. Compared to solely HFD-fed animals, plasma levels of free fatty acids (FFA) in the HFD + BCAA group are significantly further increased, due largely to AMPKα2-mediated adipocyte lipolysis. Lipolysis inhibition normalized plasma FFA levels, and improved insulin sensitivity. Surprisingly, blocking lipolysis failed to abolish BCAA-induced liver injury. Mechanistically, hepatic mTOR activation by BCAA inhibited lipid-induced hepatic autophagy, increased hepatic apoptosis, blocked hepatic FFA/triglyceride conversion, and increased hepatocyte susceptibility to FFA-mediated lipotoxicity. These data demonstrated that BCAA reduces HFD-induced body weight, at the expense of abnormal lipolysis and hyperlipidemia, causing hepatic lipotoxicity. Furthermore, BCAA directly exacerbate hepatic lipotoxicity by reducing lipogenesis and inhibiting autophagy in the hepatocyte., Highlights • BCAA cause hepatic injury via complex mechanisms involving both adipocytes and hepatic cells. • In the adipocyte, BCAA activate AMPKα2 and stimulate lipolysis, increasing plasma free fatty acids (FFA), which in turn results in hepatic FFA accumulation. • In the liver, BCAA activate mTOR and inhibit FFA to TG conversion and autophagy, intensifying FFA lipotoxicity. High fat diet (HFD) induces systemic BCAA catabolic defects. Under HFD conditions, increased BCAA consumption further increases circulating BCAA abundance. BCAA-enhanced adipocyte lipolysis induces hyperlipidemia through activating AMPKα2. Elevated circulating FFA results in insulin resistance and hepatic lipotoxicity. Moreover, BCAA activate hepatic mTOR, inhibit lipogenesis and autophagy, therefore increasing hepatic susceptibility to FFA-mediated lipotoxicity. As BCAA are abundant in protein, our results call for caution regarding the ingestion of high protein diets in obesity and diabetic individuals, unless their BCAA metabolic pathways are determined normal.