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Background: HECT domain and Ankyrin repeat Containing E3 ubiquitin-protein ligase 1 (HACE1) has been found to be associated with mitochondrial protection. Mitochondrial damage is a critical contributor to myocardial ischemia–reperfusion injury (I/RI). However, little is known about the role of HACE1 in the pathogenesis of myocardial I/RI. Methods: Male C57BL6 mice with HACE1 knockout (KO) were subjected to 30 min of ischemia via ligation of the left anterior descending artery, followed by 0, 2, 6, or 24 h of reperfusion. The mice were evaluated for myocardial histopathological injury, serum troponin I (cTnI) levels, oxidative stress injury, apoptosis and cardiac function. Prior to ischemia, Mdivi-1(1.2 mg/kg) or vehicle was administered. Results: The study revealed that increased expression of HACE1 was associated with myocardial ischemia/reperfusion injury (I/RI), and that knockout of HACE1 resulted in more severe myocardial damage and cardiac dysfunction during I/R(P < 0.05). The HACE1 knockout group exhibited higher levels of malondialdehyde (MDA), greater mitochondrial fission, and dissipation of mitochondrial membrane potential (MMP), leading to more apoptosis and severe cardiac dysfunction compared to the wild-type I/R group(P < 0.05). On the other hand, HACE1 knockout further reduced superoxide dismutase (SOD) activity in the myocardium(P < 0.05), further supporting the findings. However, the adverse effects were almost completely eliminated by pharmacological blockade of the dynamin-related protein 1 (Drp1) inhibitor, Mdivi-1, which inhibits mitochondrial fission during cardiac I/R(P < 0.05). Conclusion: Collectively, our data show that myocardial I/RI is associated with HACE1 downregulation and Drp1 activation, causing cardiomyocytes to undergo cell death. Therefore, HACE1 could be a promising therapeutic target for the treatment of myocardial I/RI. [ABSTRACT FROM AUTHOR]

AIM: This study aims to investigate the role of dynamin-related protein 1 (Drp1) in the A1 type activation of astrocytes and elucidate the underlying mechanism of abnormal astrocyte activation. METHODS: Rat astrocyte line CTX-TNA2 was divided into control group, astrocyte-conditioned medium (ACM) group, and 5, 10 and 25 μmol/L mitochondrial division inhibitor-1 (Mdivi-1; a selective inhibitor of Drp1) +ACM group. The cells in ACM group were exposed to ACM containing interleukin-1α (IL-1α), tumor necrosis factor-α (TNF-α) and complement 1q (C1q) for 24 h to induce type A1 activation, while those in Mdivi-1+ACM group were pre-treated with various concentrations of Mdivi-1 for 2 h before stimulation with ACM for 24 h. RT-qPCR was used to detect the expression levels of A1 type activation- related indicators IL-1β, TNF-α and IL-10 mRNA in each group. Immunofluorescence was utilized to assess the expression levels of A1 type activation marker molecules C3, inducible nitric oxide synthase (iNOS) and S100 calcium binding protein A10 (S100A10) . The level of mitochondrial reactive oxygen species (ROS) was measured using MitoSOX Red staining and flow cytometry analysis. The mitochondrial morphology was observed using the MICA full-field imaging analysis platform. Lastly, the expression level of mitochondrial fission protein 1 (FIS1) and the activation level of Drp1 in each group were evaluated through immunoblotting analysis. RESULTS: The RT-qPCR and immunofluorescence results indicated that the ACM group exhibited significantly elevated levels of IL-1β and TNF-α mRNA, and C3 protein expression compared with control group, along with increased iNOS protein expression and reduced IL-10 mRNA and S100A10 protein expression (P<0. 05) . Interventions with 10 and 25 μmol/L Mdivi-1 effectively inhibited the rise in IL-1β and TNF-α mRNA, and C3 and iNOS protein expression induced by ACM, while promoting S100A10 expression. MitoSOX Red staining revealed a significant increase in mitochondrial ROS levels in astrocytes stimulated by ACM, which was effectively reversed by Mdivi-1 intervention. The MICA full-field imaging analysis platform demonstrated that ACM induced the formation of round-shaped mitochondria in astrocytes, while 10 and 25 μmol/L Mdivi-1 interventions facilitated the restoration of their tubular shape. Additionally, Western blot results confirmed that Mdivi-1 intervention effectively reversed the activation of Drp1 and FIS1. CONCLUSION: The Drp1-mediated mitochondrial fission represents one of the intrinsic molecular mechanisms underlying A1 type activation of astrocytes, and Mdivi-1, as a selective inhibitor of Drp1, can effectively inhibit abnormal astrocyte activation. [ABSTRACT FROM AUTHOR]

Diabetic peripheral neuropathy (DPN) is a common complication of diabetes in both Type 1 (T1D) and Type 2 (T2D). While there are no specific medications to prevent or treat DPN, certain strategies can help halt its progression. In T1D, maintaining tight glycemic control through insulin therapy can effectively prevent or delay the onset of DPN. However, in T2D, overall glucose control may only have a moderate impact on DPN, although exercise is clearly beneficial. Unfortunately, optimal exercise may not be feasible for many patients with DPN because of neuropathic foot pain and poor balance. Exercise has several favorable effects on health parameters, including body weight, glycemic control, lipid profile, and blood pressure. We investigated the impact of an exercise mimetic, 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR), on DPN. AICAR treatment prevented or reversed experimental DPN in mouse models of both T2D and T1D. AICAR in high-fat diet (HFD-fed) mice increased the phosphorylation of AMPK in DRG neuronal extracts, and the ratio of phosphorylated AMPK to total AMPK increased by 3-fold (HFD vs. HFD+AICAR; p < 0.001). Phospho AMP increased the levels of dynamin-related protein 1 (DRP1, a mitochondrial fission marker), increased phosphorylated autophagy activating kinase 1 (ULK1) at Serine-555, and increased microtubule-associated protein light chain 3-II (LC3-II, a marker for autophagosome assembly) by 2-fold. Mitochondria isolated from DRG neurons of HFD-fed had a decrease in ADP-stimulated state 3 respiration (120 ± 20 nmol O2/min in HFD vs. 220 ± 20 nmol O2/min in control diet (CD); p < 0.001. Mitochondria isolated from HFD+AICAR-treated mice had increased state 3 respiration (240 ± 30 nmol O2/min in HFD+AICAR). However, AICAR's protection in DPN in T2D mice was also mediated by its effects on insulin sensitivity, glucose metabolism, and lipid metabolism. Drugs that enhance AMPK phosphorylation may be beneficial in the treatment of DPN. [ABSTRACT FROM AUTHOR]

Purpose: Diabetes mellitus and metabolic homeostasis disorders may benefit from white adipose tissue (WAT) browning, which is associated with mitochondrial fission. Resveratrol, a dietary polyphenol, exhibits beneficial effects against abnormalities related to metabolic diseases. However, it remains unknown whether resveratrol contributes to WAT browning by regulating mitochondrial fission. Methods: We administered resveratrol (0.4% mixed with control) to db/db mice for 12 weeks, measuring body weight, oral glucose tolerance, insulin tolerance, and histological changes. The uncoupling protein 1 (UCP1) and dynamin-related protein 1 (DRP1) expressions in the epididymal WAT were assessed via immunoblotting. Results: We found that resveratrol improved systemic glucose homeostasis and insulin resistance in db/db mice, which was associated with increased UCP1 in epididymal WAT. Resveratrol-treated mice exhibited more fragmented mitochondria and increased phosphorylation of DRP1 in the epididymal WAT of the db/db mice. These results were further confirmed in vitro, where resveratrol induced extracellular signal-regulated kinase (ERK) signaling activation, leading to phosphorylation of DRP1 at the S616 site (p-DRP1S616) and mitochondrial fission, which was reversed by an ERK inhibitor in 3T3-L1 adipocytes. Conclusion: Resveratrol plays a role in regulating the phosphorylation of ERK and DRP1, resulting in the promotion of beige cells with epididymal WAT and the improvement of glucose homeostasis. Our present study provides novel insights into the potential mechanism of resveratrol-mediated effects on WAT browning, suggesting that it is, at least in part, mediated through ERK/DRP1-mediated mitochondrial fission. [ABSTRACT FROM AUTHOR]

Yingxue Sun,1,&ast; Shi Jin,1,&ast; Jun Chen,2,&ast; Jian Zhang,1 Yufei Lu,1 Qiuyu Gu,1 Zhixin Yan,1 Weize Chen,1 Annan Chen,1 Yi Fang,1 Wenye Geng,3 Xialian Xu,1 Nana Song1 1Department of Nephrology, Zhongshan Hospital, Fudan University; Shanghai Medical Center of Kidney; Shanghai Institute of Kidney and Dialysis; Shanghai Key Laboratory of Kidney and Blood Purification; Hemodialysis Quality Control Center of Shanghai, Shanghai, 200032, People’s Republic of China; 2Department of Pathology, Changzheng Hospital, Naval Military Medical University, Shanghai, 200003, People’s Republic of China; 3Scientific Research Department of Shanghai Medical College, Fudan Zhangjiang Institute, Fudan University, Shanghai, 201203, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Xialian Xu; Nana Song, Division of Nephrology, Zhongshan Hospital, Fudan University, Shanghai, People’s Republic of China, Tel +86-021-64041990-2138, Fax +86-021-64038038, Email xu.xialian@zs-hospital.sh.cn; song.nana@zs-hospital.sh.cnObjective: This study aimed to investigate the mechanisms and specific targets of cordycepin in the treatment of renal fibrosis using a unilateral ischemia-reperfusion (UIR) model.Methods: A UIR mouse model was established, followed by intraperitoneal injections of cordycepin and Mdivi-1. Masson’s trichrome staining and PAS staining were used to identify renal tubulointerstitial fibrosis and assess the degree of renal injury. Fibrosis markers and mitochondrial dynamics-related proteins were evaluated using Western blotting, while differential gene expression and pathway enrichment were analyzed by RNA-seq. Molecular docking, molecular dynamics simulations and surface plasmon resonance were conducted to validate the specific binding sites of cordycepin on the target protein Drp1. Immunofluorescence and in vitro experiments further elucidated the therapeutic mechanism of cordycepin.Results: In vivo experiments showed that intraperitoneal injection of cordycepin significantly reduced renal inflammation and fibrosis, lowered serum creatinine levels, and decreased collagen deposition. Transcriptome analysis revealed that cordycepin treatment downregulated the mitochondrial fission pathway and upregulated the mitochondrial fusion pathway. Western blotting showed reduced levels of fibrosis markers α-SMA and FN, as well as downregulation of Drp1, MFF, and Fis1, and upregulation of OPA1 and Mfn2. In vitro, cordycepin inhibited TGF-β-induced injury in NRK-52E cells, reducing Drp1 expression and IL-6 secretion. Crosstalk experiments confirmed that decreased IL-6 levels were crucial for cordycepin anti-fibrotic effects by suppressing fibroblast activation.Conclusion: Cordycepin ameliorates renal fibrosis by targeting Drp1 to inhibit mitochondrial fission in injured renal tubular epithelial cells, reducing IL-6 secretion and inhibiting fibroblast activation.Keywords: cordycepin, Drp1, renal fibrosis, mitochondrial fission, UIR, IL-6

Abstract Background HECT domain and Ankyrin repeat Containing E3 ubiquitin-protein ligase 1 (HACE1) has been found to be associated with mitochondrial protection. Mitochondrial damage is a critical contributor to myocardial ischemia–reperfusion injury (I/RI). However, little is known about the role of HACE1 in the pathogenesis of myocardial I/RI. Methods Male C57BL6 mice with HACE1 knockout (KO) were subjected to 30 min of ischemia via ligation of the left anterior descending artery, followed by 0, 2, 6, or 24 h of reperfusion. The mice were evaluated for myocardial histopathological injury, serum troponin I (cTnI) levels, oxidative stress injury, apoptosis and cardiac function. Prior to ischemia, Mdivi-1(1.2 mg/kg) or vehicle was administered. Results The study revealed that increased expression of HACE1 was associated with myocardial ischemia/reperfusion injury (I/RI), and that knockout of HACE1 resulted in more severe myocardial damage and cardiac dysfunction during I/R(P

Abstract Mutations in the mitochondrial enzyme propionyl-CoA carboxylase (PCC) cause propionic aciduria (PA). Chronic kidney disease (CKD) is a known long-term complication. However, good metabolic control and standard therapy fail to prevent CKD. The pathophysiological mechanisms of CKD are unclear. We investigated the renal phenotype of a hypomorphic murine PA model (Pcca -/- (A138T)) to identify CKD-driving mechanisms. Pcca -/- (A138T) mice show elevated retention parameters and express markers of kidney damage progressing with time. Morphological assessment of the Pcca -/- (A138T) mouse kidneys indicated partial flattening of tubular epithelial cells and focal tubular-cystic dilation. We observed altered renal mitochondrial ultrastructure and mechanisms acting against oxidative stress were active. LC–MS/MS analysis confirmed disease-specific metabolic signatures and revealed disturbances in mitochondrial energy generation via the TCA cycle. Our investigations revealed altered mitochondrial networks shifted towards fission and a marked reduction of mitophagy. We observed a steep reduction of PGC-1-α, the key mediator modulating mitochondrial functions and a counter actor of mitochondrial fission. Our results suggest that impairment of mitochondrial homeostasis and quality control are involved in CKD development in PA. Therapeutic targeting of the identified pathways might help to ameliorate CKD in addition to the current treatment strategies.

Abstract Backgroud Recent studies have reported mitochondrial damage and metabolic dysregulation in BPD, but the changes in mitochondrial dynamics and glucose metabolic reprogramming in ATII cells and their regulatory relationship have not been reported. Methods Neonatal rats in this study were divided into model (FIO2:85%) and control (FIO2: 21%) groups. Lung tissues were extracted at 3, 7, 10 and 14 postnatal days and then conducted HE staining for histopathological observation. We assessed the expression of mitochondria dynamic associated proteins and glycolysis associated enzymes in lung tissues, primary ATII cells and RLE-6TN cells. Double immunofluorescence staining was used to confirm the co-localization of DRP1 and ATII cells. Real-time analyses of ECAR and OCR were performed with primary ATII cells using Seahorse XF96. ATP concentration was measured using an ATP kit. We treated RLE-6TN cells at 85% hyperoxia for 48 h with mitochondrial fission inhibitor Mdivi-1 to verify the role of DRP1 in regulating glucose metabolic reprogramming. Findings We found that hyperoxia causes ATII cells’ mitochondrial morphological change. The expression of DRP1 and p-DRP1 increased in lung tissue and primary ATII cells of neonatal rats exposed to hyperoxia. Glycolysis related enzymes including PFKM, HK2, and LDHA were also increased. Hyperoxia inhibited ATP production in ATII cells. In RLE-6TN cells, we verified that the administration of Mdivi-1 could alleviate the enhancement of aerobic glycolysis and fragmentation of mitochondria caused by hyperoxia. Interpretations Hyperoxia exposure leads to increased mitochondrial fission in ATII cells and mediates the reprogramming of glucose metabolism via the DRP1 signaling pathway. Inhibiting the activation of DRP1 signaling pathway may be a promising therapeutic target for BPD.

Abstract The aberrant acetylation of mitochondrial proteins is involved in the pathogenesis of multiple diseases including neurodegenerative diseases and cerebral ischemic injury. Previous studies have shown that depletion of mitochondrial NAD+, which is necessary for mitochondrial deacetylase activity, leads to decreased activity of mitochondrial deacetylase and thus causes hyperacetylation of mitochondrial proteins in ischemic brain tissues, which results in altered mitochondrial dynamics. However, it remains largely unknown about how mitochondrial dynamics-related protein Drp1 is acetylated in ischemic neuronal cells and brain tissues. Here, we showed that Drp1 and GCN5L1 expression was up-regulated in OGD-treated neuronal cells and ischemic brain tissues induced by dMCAO, accompanied by the increased mitochondrial fission, mtROS accumulation, and cell apoptosis. Further, we confirmed that ischemia/hypoxia promoted Drp1 interaction with GCN5L1 in neuronal cells and brain tissues. GCN5L1 knockdown attenuated, while its overexpression enhanced Drp1 acetylation and mitochondrial fission, indicating that GCN5L1 plays a crucial role in ischemia/hypoxia-induced mitochondrial fission by acetylating Drp1. Mechanistically, ischemia/hypoxia induced Drp1 phosphorylation by CDK5 upregulation-mediated activation of AMPK in neuronal cells, which in turn facilitated the interaction of GCN5L1 with Drp1, thus enhancing Drp1 acetylation and mitochondrial fission. Accordingly, inhibition of AMPK alleviated ischemia/hypoxia- induced Drp1 acetylation and mitochondrial fission and protected brain tissues from ischemic damage. These findings provide a novel insight into the functional roles of GCN5L1 in regulating Drp1 acetylation and identify a previously unrecognized CDK5-AMPK-GCN5L1 pathway that mediates the acetylation of Drp1 in ischemic brain tissues.

Abstract Background During the aging process, the number and functional activity of endothelial progenitor cells (EPCs) are impaired, leading to the unsatisfactory efficacy of transplantation. Previous studies demonstrated that Yiqihuoxue decoction (Ginseng-Sanqi-Chuanxiong, GSC) exerts anti-vascular aging effects. The purpose of this study is to evaluated the effects of GSC on D-galactose (D-gal)induced senescence and the underlying mechanisms. Methods The levels of cellular senescence-related markers P16, P21, P53, AMPK and p-AMPK were detected by Western blot analysis (WB). SA-β-gal staining was used to evaluate cell senescence. EPCs function was measured by CCK-8, Transwell cell migration and cell adhesion assay. The morphological changes of mitochondria were detected by confocal microscopy. The protein and mRNA expression of mitochondrial fusion fission Drp1, Mff, Fis1, Mfn1, Mfn2 and Opa1 in mitochondria were detect using WB and RT–qPCR. Mitochondrial membrane potential, mtROS and ATP of EPCs were measured using IF. H&E staining was used to observe the pathological changes and IMT of the aorta. The expressions of AGEs, MMP-2 and VEGF in aorta were measured using Immunohistochemical (IHC). The levels of SOD, MDA, NO and ET-1 in serum were detected by SOD, MDA and NO kits. Results In vitro, GSC ameliorated the senescence of EPCs induced by D-gal and reduced the expression of P16, P21 and P53. The mitochondrial morphology of EPCs was restored, the expression of mitochondrial Drp1, Mff and Fis1 protein was decreased, the levels of mtROS and ATP were decreased, and mitochondrial function was improved. Meanwhile, the expression of AMPK and p-AMPK increased. The improvement effects of GSC on aging and mitochondrial morphology and function were were hindered after adding AMPK inhibitor. In vivo, GSC improved EPCs efficiency, ameliorated aortic structural disorder and decreased IMT in aging mice. The serum SOD level increased and MDA level decreased, indicating the improvement of antioxidant capacity. Increased NO content and ET-1 content suggested improvement of vascular endothelial function. The changes observed in SOD and MMP-2 suggested a reduction in vascular stiffness and the degree of vascular damage. The decreased expression of P21 and P53 indicates the delay of vascular senescence.

Backgroud: Recent studies have reported mitochondrial damage and metabolic dysregulation in BPD, but the changes in mitochondrial dynamics and glucose metabolic reprogramming in ATII cells and their regulatory relationship have not been reported. Methods: Neonatal rats in this study were divided into model (FIO2:85%) and control (FIO2: 21%) groups. Lung tissues were extracted at 3, 7, 10 and 14 postnatal days and then conducted HE staining for histopathological observation. We assessed the expression of mitochondria dynamic associated proteins and glycolysis associated enzymes in lung tissues, primary ATII cells and RLE-6TN cells. Double immunofluorescence staining was used to confirm the co-localization of DRP1 and ATII cells. Real-time analyses of ECAR and OCR were performed with primary ATII cells using Seahorse XF96. ATP concentration was measured using an ATP kit. We treated RLE-6TN cells at 85% hyperoxia for 48 h with mitochondrial fission inhibitor Mdivi-1 to verify the role of DRP1 in regulating glucose metabolic reprogramming. Findings: We found that hyperoxia causes ATII cells' mitochondrial morphological change. The expression of DRP1 and p-DRP1 increased in lung tissue and primary ATII cells of neonatal rats exposed to hyperoxia. Glycolysis related enzymes including PFKM, HK2, and LDHA were also increased. Hyperoxia inhibited ATP production in ATII cells. In RLE-6TN cells, we verified that the administration of Mdivi-1 could alleviate the enhancement of aerobic glycolysis and fragmentation of mitochondria caused by hyperoxia. Interpretations: Hyperoxia exposure leads to increased mitochondrial fission in ATII cells and mediates the reprogramming of glucose metabolism via the DRP1 signaling pathway. Inhibiting the activation of DRP1 signaling pathway may be a promising therapeutic target for BPD. [ABSTRACT FROM AUTHOR]

Both human and animal experiments have demonstrated that energy metabolism dysfunction in neurons after seizures is associated with an imbalance in mitochondrial fusion/fission dynamics. Effective neuronal mitochondrial dynamics regulation strategies remain elusive. Nicotinamide mononucleotide (NMN) can ameliorate mitochondrial functional and oxidative stress in age‐related diseases. But whether NMN improves mitochondrial energy metabolism to exert anti‐epileptic effects is unclear. This study aims to clarify if NMN can protect neurons from pentylenetetrazole (PTZ) or Mg2+‐free‐induced mitochondrial disorder and apoptosis via animal and cell models. We established a continuous 30‐day PTZ (37 mg/kg) intraperitoneal injection‐induced epileptic mouse model and a cell model induced by Mg2+‐free solution incubation to explore the neuroprotective effects of NMN. We found that NMN treatment significantly reduced the seizure intensity of PTZ‐induced epileptic mice, improved their learning and memory ability, and enhanced their motor activity and exploration desire. At the same time, in vitro and in vivo experiments showed that NMN can inhibit neuronal apoptosis and improve the mitochondrial energy metabolism function of neurons. In addition, NMN down‐regulated the expression of mitochondrial fission proteins (Drp1 and Fis1) and promoted the expression of mitochondrial fusion proteins (Mfn1 and Mfn2) by activating the SIRT1‐PGC‐1α pathway, thereby inhibiting PTZ or Mg2+‐free extracellular solution‐induced mitochondrial dysfunction, cell apoptosis, and oxidative stress. However, combined intervention of SIRT1 inhibitor, Selisistat, and PGC‐1α inhibitor, SR‐18292, eliminated the regulatory effect of NMN pre‐treatment on mitochondrial fusion and fission proteins and apoptosis‐related proteins. Therefore, NMN intervention may be a new potential treatment for cognitive impairment and behavioral disorders induced by epilepsy, and targeting the SIRT1‐PGC‐1α pathway may be a promising therapeutic strategy for seizures. [ABSTRACT FROM AUTHOR]

Acute kidney injury (AKI) induced by renal ischemia–reperfusion injury (IRI) has a high morbidity and mortality, representing a worldwide problem. The kidney is an essential organ of metabolism that has high blood perfusion and is the second most mitochondria‐rich organ after the heart because of the high ATP demands of its essential functions of nutrient reabsorption, acid–base and electrolyte balance, and hemodynamics. Thus, these energy‐intensive cells are particularly vulnerable to mitochondrial dysfunction. As the bulk of glomerular ultrafiltrate reabsorption by proximal tubules occurs via active transport, the mitochondria of proximal tubules must be equipped for detecting and responding to fluctuations in energy availability to guarantee efficient basal metabolism. Any insults to mitochondrial quality control mechanisms may lead to biological disruption, blocking the clearance of damaged mitochondria and resulting in morphological change and tissue dysfunction. Extensive research has shown that mitochondria have pivotal roles in acute kidney disease, so in this article, we discuss the role of mitochondria, their dynamics and mitophagy in renal ischemia–reperfusion injury. [ABSTRACT FROM AUTHOR]

Mutations in the mitochondrial enzyme propionyl-CoA carboxylase (PCC) cause propionic aciduria (PA). Chronic kidney disease (CKD) is a known long-term complication. However, good metabolic control and standard therapy fail to prevent CKD. The pathophysiological mechanisms of CKD are unclear. We investigated the renal phenotype of a hypomorphic murine PA model (Pcca-/-(A138T)) to identify CKD-driving mechanisms. Pcca-/-(A138T) mice show elevated retention parameters and express markers of kidney damage progressing with time. Morphological assessment of the Pcca-/-(A138T) mouse kidneys indicated partial flattening of tubular epithelial cells and focal tubular-cystic dilation. We observed altered renal mitochondrial ultrastructure and mechanisms acting against oxidative stress were active. LC–MS/MS analysis confirmed disease-specific metabolic signatures and revealed disturbances in mitochondrial energy generation via the TCA cycle. Our investigations revealed altered mitochondrial networks shifted towards fission and a marked reduction of mitophagy. We observed a steep reduction of PGC-1-α, the key mediator modulating mitochondrial functions and a counter actor of mitochondrial fission. Our results suggest that impairment of mitochondrial homeostasis and quality control are involved in CKD development in PA. Therapeutic targeting of the identified pathways might help to ameliorate CKD in addition to the current treatment strategies. [ABSTRACT FROM AUTHOR]

In the process of cardiac fibrosis, the balance between the Wnt/β-catenin signalling pathway and Wnt inhibitory factor genes plays an important role. Secreted frizzled-related protein 3 (sFRP3), a Wnt inhibitory factor, has been linked to epigenetic mechanisms. However, the underlying role of epigenetic regulation of sFRP3, which is crucial in fibroblast proliferation and migration, in cardiac fibrosis have not been elucidated. Therefore, we aimed to investigate epigenetic and transcription of sFRP3 in cardiac fibrosis. Using clinical samples and animal models, we investigated the role of sFRP3 promoter methylation in potentially enhancing cardiac fibrosis. We also attempted to characterize the underlying mechanisms using an isoprenaline-induced cardiac fibrosis mouse model and cultured primary cardiac fibroblasts. Hypermethylation of sFRP3 was associated with perpetuation of fibroblast activation and cardiac fibrosis. Additionally, mitochondrial fission, regulated by the Drp1 protein, was found to be significantly altered in fibrotic hearts, contributing to fibroblast proliferation and cardiac fibrosis. Epigenetic modification of sFRP3 promoter methylation also influenced mitochondrial dynamics, linking sFRP3 repression to excessive mitochondrial fission. Moreover, sFRP3 hypermethylation was mediated by DNA methyltransferase 3A (DNMT3A) in cardiac fibrosis and fibroblasts, and DNMT3A knockdown demethylated the sFRP3 promoter, rescued sFRP3 loss, and ameliorated the isoprenaline-induced cardiac fibrosis and cardiac fibroblast proliferation, migration and mitochondrial fission. Mechanistically, DNMT3A was shown to epigenetically repress sFRP3 expression via promoter methylation. We describe a novel epigenetic mechanism wherein DNMT3A represses sFRP3 through promoter methylation, which is a critical mediator of cardiac fibrosis and mitochondrial fission. Our findings provide new insights for the development of preventive measures for cardiac fibrosis. DNA methyltransferase DNMT3A causes upregulation of sFRP3 methylation levels in cardiac fibrosis and cardiac fibroblasts. Subsequently, sFRP3 downregulation promotes cardiac fibroblast proliferation, migration and mitochondrial fission. DNA methyltransferase DNMT3A repressed sFRP3 to facilitate cardiac fibroblast activation and cardiac fibrosis. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD), the most prevalent cause of dementia, is a progressive neurodegenerative condition that commences subtly and inexorably worsens over time. Despite considerable research, a specific drug that can fully cure or effectively halt the progression of AD remains elusive. Nitric oxide (NO), a crucial signaling molecule in the nervous system, is intimately associated with hallmark pathological changes in AD, such as amyloid-beta deposition and tau phosphorylation. Several therapeutic strategies for AD operate through the nitric oxide synthase/NO system. However, the potential neurotoxicity of NO introduces an element of controversy regarding its therapeutic utility in AD. This review focuses on research findings concerning NO's role in experimental AD and its underlying mechanisms. Furthermore, we have proposed directions for future research based on our current comprehension of this critical area. [ABSTRACT FROM AUTHOR]

The Zika virus (ZIKV) outbreaks and its co-relation with microcephaly have become a global health concern. It is primarily transmitted by a mosquito, but can also be transmitted from an infected mother to her fetus causing impairment in brain development, leading to microcephaly. However, the underlying molecular mechanism of ZIKV-induced microcephaly is poorly understood. In this study, we explored the role of ZIKV non-structural protein NS4A and NS4B in ZIKV pathogenesis in a well-characterized primary culture of human fetal neural stem cells (fNSCs). We observed that the co-transfection of NS4A and NS4B altered the neural stem cell fate by arresting proliferation and inducing premature neurogenesis. NS4A + NS4B transfection in fNSCs increased autophagy and dysregulated notch signaling. Further, it also altered the regulation of downstream genes controlling cell proliferation. Additionally, we reported that 3 methyl-adenine (3-MA), a potent autophagy inhibitor, attenuated the deleterious effects of NS4A and NS4B as evidenced by the rescue in Notch1 expression, enhanced proliferation, and reduced premature neurogenesis. Our attempts to understand the mechanism of autophagy induction indicate the involvement of mitochondrial fission and ROS. Collectively, our findings highlight the novel role of NS4A and NS4B in mediating NSC fate alteration through autophagy-mediated notch degradation. The study also helps to advance our understanding of ZIKV-induced neuropathogenesis and suggests autophagy as a potential target for anti-ZIKV therapeutic intervention. [ABSTRACT FROM AUTHOR]

Mitochondrial homeostasis plays a crucial role in degenerative joint diseases, including cartilaginous endplate (CEP) degeneration. To date, research into mitochondrial dynamics in IVDD is at an early stage. Since Piezo1 is a novel Ca2+‐permeable channel, we asked whether Piezo1 could modulate mitochondrial fission through Ca2+ signalling during CEP degeneration. In vitro and in vivo models of inflammation‐induced CEP degeneration were established with lipopolysaccharide (LPS). We found increased expression of Piezo1 in degenerated CEP tissues and LPS‐treated CEP cells. The Piezo1 activator Yoda1 exacerbated CEP cell senescence and apoptosis by triggering Ca2+ influx. Yoda1 also induced mitochondrial fragmentation and dysfunction. In contrast, the Piezo1 inhibitor GsMTx4 exerted cytoprotective effects in LPS‐treated CEP cells. Additionally, the CaMKII inhibitor KN‐93 reversed Yoda1‐induced mitochondrial fission and restored mitochondrial function. Mechanistically, the phosphorylation and mitochondrial translocation of Drp1 were regulated by the Ca2+/CaMKII signalling. The Drp1 inhibitor Mdivi‐1 suppressed mitochondrial fission, then reduced mitochondrial dysfunction and CEP cell death. Moreover, knockdown of Piezo1 by siRNA hindered CaMKII and Drp1 activation, facilitating the redistribution of mitochondrial Drp1 to the cytosol in LPS‐treated CEP cells. Piezo1 silencing improved mitochondrial morphology and function, thereby rescuing CEP cell senescence and apoptosis under inflammatory conditions. Finally, subendplate injection of GsMTx4 or AAV‐shPiezo1 alleviated CEP degeneration in a rat model. Thus, Piezo1 may exacerbate inflammation‐induced CEP degeneration by triggering mitochondrial fission and dysfunction via the Ca2+/CaMKII/Drp1 axis. [ABSTRACT FROM AUTHOR]

Mitochondrial DNA (mtDNA) is present in multiple copies within cells and is required for mitochondrial ATP generation. Even within individual cells, mtDNA copies can differ in their sequence, a state known as heteroplasmy. The principles underlying dynamic changes in the degree of heteroplasmy remain incompletely understood, due to the inability to monitor this phenomenon in real time. Here, we employ mtDNA-based fluorescent markers, microfluidics, and automated cell tracking, to follow mtDNA variants in live heteroplasmic yeast populations at the single-cell level. This approach, in combination with direct mtDNA tracking and data-driven mathematical modeling reveals asymmetric partitioning of mtDNA copies during cell division, as well as limited mitochondrial fusion and fission frequencies, as critical driving forces for mtDNA variant segregation. Given that our approach also facilitates assessment of segregation between intact and mutant mtDNA, we anticipate that it will be instrumental in elucidating the mechanisms underlying the purifying selection of mtDNA. Synopsis: The basis for dynamic changes in mitochondria DNA variations in cell populations, known as heteroplasmy, remains unclear. Here, live-cell tracking of mtDNA variants in yeast populations reveals mechanistic principles underlying mtDNA variant segregation. mtDNA variants encoding fluorescent reporters facilitate microscopy approaches for monitoring mtDNA variant segregation in real-time in a dividing yeast population. Asymmetric partitioning of mtDNA copies between mother and daughter cells as well as mitochondrial fission rates determine the rate of mtDNA variant segregation. mtDNA variant segregation is delayed in ∆mrx6 cells with increased mtDNA copy number. The imaging approach allows monitoring of purifying selection against mutant mtDNA. Tracking mtDNA variants in live yeast populations reveals asymmetric partitioning of mtDNA copies during cell division as well as limited mitochondrial fusion/fission frequencies as critical drivers of mtDNA variant segregation. [ABSTRACT FROM AUTHOR]

Cisplatin-induced acute kidney injury (AKI) is characterized by mitochondrial damage and apoptosis, and safe and effective therapeutic agents are urgently needed. Renal tubular epithelial cells, the main site of AKI, are enriched with a large number of mitochondria, which are crucial for the progression of AKI with an impaired energy supply. Vincamine has anti-inflammatory and antioxidant effects in mouse AKI models. As a natural compound derived from Tabernaemontana pandacaqui , (+)-14, 15-Dehydrovincamine and Vincamine differ in structure by only one double bond, and the role and exact mechanism of (+)-14, 15-Dehydrovincamine remains to be elucidated in AKI. The present study demonstrated that (+)-14,15-Dehydrovincamine significantly ameliorated mitochondrial dysfunction and maintained mitochondrial homeostasis in a cisplatin-induced AKI model. Furthermore, (+)-14,15-Dehydrovincamine ameliorates cytochrome C-dependent apoptosis in renal tubular epithelial cells. c-Jun NH2-terminal kinase (JNK) was identified as a potential target protein of (+)-14,15-Dehydrovincamine attenuating AKI by network pharmacological analysis. (+)-14,15-Dehydrovincamine inhibited cisplatin-induced JNK activation, mitochondrial fission factor (Mff) phosphorylation, and dynamin-related protein 1 (Drp1) translocation to the mitochondria in renal tubular epithelial cells. Meanwhile, the JNK activator anisomycin restored Mff phosphorylation and Drp1 translocation, counteracting the protective effect of (+)-14,15-Dehydrovincamine on mitochondrial dysfunction in cisplatin-induced TECs injury. In conclusion, (+)-14,15-Dehydrovincamine reduced mitochondrial fission, maintained mitochondrial homeostasis, and attenuated apoptosis by inhibiting the JNK/Mff/Drp1 pathway, which in turn ameliorated cisplatin-induced AKI. [Display omitted] • (+)-14,15-Dehydrovincamine is superior to Vincamine against cisplatin-induced TEC injury. • (+)-14,15-Dehydrovincamine attenuates cisplatin-induced AKI in a mouse model. • (+)-14,15-Dehydrovincamine reduces mitochondrial fission through the JNK/Mff/Drp1 pathway. [ABSTRACT FROM AUTHOR]

Mitochondria are dynamic organelles that continuously undergo fusion/fission to maintain normal cell physiological activities and energy metabolism. When mitochondrial dynamics is unbalanced, mitochondrial homeostasis is broken, thus damaging mitochondrial function. Accumulating evidence demonstrates that impairment in mitochondrial dynamics leads to lung tissue injury and pulmonary disease progression in a variety of disease models, including inflammatory responses, apoptosis, and barrier breakdown, and that the role of mitochondrial dynamics varies among pulmonary diseases. These findings suggest that modulation of mitochondrial dynamics may be considered as a valid therapeutic strategy in pulmonary diseases. In this review, we discuss the current evidence on the role of mitochondrial dynamics in pulmonary diseases, with a particular focus on its underlying mechanisms in the development of acute lung injury (ALI)/acute respiratory distress syndrome (ARDS), chronic obstructive pulmonary disease (COPD), asthma, pulmonary fibrosis (PF), pulmonary arterial hypertension (PAH), lung cancer and bronchopulmonary dysplasia (BPD), and outline effective drugs targeting mitochondrial dynamics‐related proteins, highlighting the great potential of targeting mitochondrial dynamics in the treatment of pulmonary disease. [ABSTRACT FROM AUTHOR]

Vascular endothelial senescence is a major risk factor for diabetic vascular complications. Abnormal mitochondrial fission by dynamically related protein 1 (DRP1) accelerates vascular endothelial cell senescence. Homoplantaginin (Hom) is a flavonoid in Salvia plebeia R. Br. with protecting mitochondrial and repairing vascular properties. However, the relevant mechanism of Hom against diabetic vascular endothelial cell senescence remains unclear. Here, we used db/db mice and high glucose (HG)‐treated human umbilical vein endothelial cells (HUVECs) to assess the anti‐vascular endothelial cell senescence of Hom. We found that Hom inhibited senescence‐associated β‐galactosidase activity, decreased the levels of senescence markers, and senescence‐associated secretory phenotype factors. Additionally, Hom inhibited the expression of cGAS–STING pathway and downstream inflammatory factors. STING inhibitor H‐151 delayed endothelial senescence, whereas STING overexpression attenuated the anti‐endothelial senescence effect of Hom. Furthermore, we observed that Hom reduced mitochondrial fragmentation and inhibited abnormal mitochondrial fission using transmission electron microscopy. Importantly, Hom has a stronger effect on mitochondrial fission protein than mitochondrial fusion protein, especially downregulated the expression of DRP1. DRP1 inhibitor Mdivi‐1 suppressed cGAS‐STING pathway and vascular endothelial senescence, yet DRP1 agonist FCCP attenuated the effect of Hom. Surprisingly, Hom blunted abnormal mitochondrial fission mediated by DRP1 mitochondrial localization, suppressed interaction of DRP1 with VDAC1 and prevented VDAC1 oligomerization, which was necessary for mtDNA escape and subsequent cGAS–STING pathway activation. These results revealed a previously unrecognized mechanism that Hom alleviated vascular endothelial senescence by inhibited mtDNA–cGAS–STING signaling pathway via blunting DRP1–mitochondrial fission–VDAC1 axis. [ABSTRACT FROM AUTHOR]

Sepsis-associated organ dysfunction plays a critical role in its high mortality, mainly in connection with mitochondrial dysfunction. Whether the inhibition of mitochondrial fission is beneficial to sepsis-related organ dysfunction and underlying mechanisms are unknown. Cecal ligation and puncture induced sepsis in rats and dynamic related protein 1 knockout mice, lipopolysaccharide-treated vascular smooth muscle cells and cardiomyocytes, were used to explore the effects of inhibition of mitochondrial fission and specific mechanisms. Our study showed that mitochondrial fission inhibitor Mdivi-1 could antagonize sepsisinduced organ dysfunction including heart, vascular smooth muscle, liver, kidney, and intestinal functions, and prolonged animal survival. The further study showed that mitochondrial functions such as mitochondrial membrane potential, adenosinetriphosphate contents, reactive oxygen species, superoxide dismutase and malonaldehyde were recovered after Mdivi-1 administration via improving mitochondrial morphology. And sepsis-induced inflammation and apoptosis in heart and vascular smooth muscle were alleviated through inhibition of mitochondrial fission and mitochondrial function improvement. The parameter trends in lipopolysaccharidestimulated cardiomyocytes and vascular smooth muscle cells were similar in vivo. Dynamic related protein 1 knockout preserved sepsis-induced organ dysfunction, and the animal survival was prolonged. Taken together, this finding provides a novel effective candidate therapy for severe sepsis/septic shock and other critical clinical diseases. [ABSTRACT FROM AUTHOR]

Alzheimer's diseases (AD) patients suffer from more serious bone loss than cognitively normal subjects at the same age. Type H blood vessels were tightly associated with bone homeostasis. However, few studies have concentrated on bone vascular alteration and its role in AD‐related bone loss. In this study, APP/PS1 mice (4‐ and 8‐month‐old) and age‐matched wild‐type mice were used to assess the bone vascular alteration and its role in AD‐related bone loss. Transmission electron microscopy, immunofluorescence staining and iGPS 1.0 software database were utilized to investigate the molecular mechanism. Mitochondrial division inhibitor (Mdivi‐1) and GSK‐3β inhibitor (LiCl) were used to rescue type H blood vessels injury and verify the molecular mechanism. Our results revealed that APP/PS1 mice exhibited more serious bone blood vessels injury and bone loss during ageing. The bone blood vessel injury, especially in type H blood vessels, was accompanied by impaired vascularized osteogenesis in APP/PS1 mice. Further exploration indicated that beta‐amyloid (Aβ) promoted the apoptosis of vascular endothelial cells (ECs) and resulted in type H blood vessels injury. Mechanistically, Aβ‐induced excessive mitochondrial fission was found to be essential for the apoptosis of ECs. GSK‐3β was identified as a key regulatory target of Aβ‐induced excessive mitochondrial fission and bone loss. The findings delineated that Aβ‐induced excessive mitochondrial fission drives type H blood vessels injury, leading to aggravate bone loss in APP/PS1 mice and GSK‐3β inhibitor emerges as a potential therapeutic strategy. [ABSTRACT FROM AUTHOR]

Dystrophic calcinosis, which is the accumulation of insoluble calcified crystalline materials within tissues with normal circulating calcium and phosphorus levels, is a frequent finding in systemic sclerosis (SSc) and represents a major burden for patients. In SSc, calcinosis poses significant challenges in management due to the associated risk of severe complications such as infection, ulceration, pain, reduction in functional capacity and quality of life, and lack of standardized treatment choices. The exact pathogenesis of calcinosis is still unknown. There are multifaceted factors contributing to calcinosis development, including osteogenic differentiation of cells, imbalance between promoter and inhibitors of mineralization, local disturbance in calcium and phosphate levels, and extracellular matrix as a template for mineralization. Several pathophysiological changes observed in SSc such as ischemia, exacerbated production of excessive reactive oxygen species, inflammation, production of inflammatory cytokines, acroosteolysis, and increased extracellular matrix production may promote the development of calcinosis in SSc. Furthermore, mitochondrial dynamics, particularly fission function through the activity of dynamin-related protein-1, may have an effect on the dystrophic calcinosis process. In-depth investigations of cellular mechanisms and microenvironmental influences can offer valuable insights into the complex pathogenesis of calcinosis in SSc, providing potential targeting pathways for calcinosis treatment. [ABSTRACT FROM AUTHOR]

Background: During the aging process, the number and functional activity of endothelial progenitor cells (EPCs) are impaired, leading to the unsatisfactory efficacy of transplantation. Previous studies demonstrated that Yiqihuoxue decoction (Ginseng-Sanqi-Chuanxiong, GSC) exerts anti-vascular aging effects. The purpose of this study is to evaluated the effects of GSC on D-galactose (D-gal)induced senescence and the underlying mechanisms. Methods: The levels of cellular senescence-related markers P16, P21, P53, AMPK and p-AMPK were detected by Western blot analysis (WB). SA-β-gal staining was used to evaluate cell senescence. EPCs function was measured by CCK-8, Transwell cell migration and cell adhesion assay. The morphological changes of mitochondria were detected by confocal microscopy. The protein and mRNA expression of mitochondrial fusion fission Drp1, Mff, Fis1, Mfn1, Mfn2 and Opa1 in mitochondria were detect using WB and RT–qPCR. Mitochondrial membrane potential, mtROS and ATP of EPCs were measured using IF. H&E staining was used to observe the pathological changes and IMT of the aorta. The expressions of AGEs, MMP-2 and VEGF in aorta were measured using Immunohistochemical (IHC). The levels of SOD, MDA, NO and ET-1 in serum were detected by SOD, MDA and NO kits. Results: In vitro, GSC ameliorated the senescence of EPCs induced by D-gal and reduced the expression of P16, P21 and P53. The mitochondrial morphology of EPCs was restored, the expression of mitochondrial Drp1, Mff and Fis1 protein was decreased, the levels of mtROS and ATP were decreased, and mitochondrial function was improved. Meanwhile, the expression of AMPK and p-AMPK increased. The improvement effects of GSC on aging and mitochondrial morphology and function were were hindered after adding AMPK inhibitor. In vivo, GSC improved EPCs efficiency, ameliorated aortic structural disorder and decreased IMT in aging mice. The serum SOD level increased and MDA level decreased, indicating the improvement of antioxidant capacity. Increased NO content and ET-1 content suggested improvement of vascular endothelial function. The changes observed in SOD and MMP-2 suggested a reduction in vascular stiffness and the degree of vascular damage. The decreased expression of P21 and P53 indicates the delay of vascular senescence. [ABSTRACT FROM AUTHOR]