SENP1-Sirt3 Signaling Controls Mitochondrial Protein Acetylation and Metabolism

SENP1-Sirt3 axis promotes cholesterol biosynthesis in tumor-associated macrophages to suppress anti-tumor immunity

Tumor-associated macrophages (TAMs) play a multifaceted role in the tumor microenvironment, notably by suppressing antitumor immune responses through immunosuppressive mechanisms. TAMs secrete a range of cytokines that simultaneously inhibit T cell function and foster a microenvironment that supports tumor progression and dissemination. Our study has delved into the intricate relationship between the metabolic reprogramming of TAMs and their impact on tumor progression. Mitochondrial metabolic reprogramming mediated by the SENP1-Sirt3 axis altered the dynamics and activity of tumor-infiltrating immune cells, including macrophages and CD8+ T lymphocytes. SENP1-Sirt3 axis increases the level of acetyl-CoA in macrophage mitochondria, which in turn promotes cholesterol biosynthesis in macrophages. The upregulation of cholesterol synthesis is a key factor in driving macrophage polarization towards the immunosuppressive M2 phenotype, which in turn supports tumor development. Notably, increased cholesterol levels contributed to a reduction in the number and activity of CD8+ T cells, which are essential for mounting an effective immune response against cancer cells. These findings suggest that targeting cholesterol biosynthesis in TAMs may be a promising strategy for cancer immunotherapy. SIGNIFICANCE: Activation of the SENP1-Sirt3 axis initiates mitochondrial metabolic reprogramming in tumor-associated macrophages (TAMs), leading to enhanced cholesterol and acetyl-CoA production, M2 macrophage polarization, and impaired CD8+ T cell anti-tumor responses.

CD47-blocking antibody confers metabolic benefits against obesity

CD47-blocking antibody is a well-known potential antibody drug for tumor immunotherapy. However, it is unclear whether CD47-blocking antibody can protect against metabolic disorders. We report that high-fat diet (HFD)-induced obesity increases CD47 expression, while exercise downregulates it in skeletal muscle. Administration of CD47-blocking antibody in mice prevents HFD-induced weight gain and glucose intolerance, enhances exercise capacity, and improves body composition and skeletal muscle mitochondrial function. Mechanistically, the protective effects conferred by CD47-blocking antibody are mediated through activation of AMP-activated protein kinase (AMPK) in skeletal muscle. Consistently, muscle-specific CD47-knockout mice show similar metabolic improvements, indicating a direct muscle-specific role of CD47 in regulating AMPK activation in vivo. Furthermore, the CD47-blocking antibody reduces the phosphorylation of heat shock protein 90α (HSP90α) to activate AMPK in skeletal muscle. In conclusion, CD47-blocking antibody confers metabolic benefits by activating the AMPK pathway in skeletal muscle.

SIRT3-Mediated Deacetylation of DRP1K711 Prevents Mitochondrial Dysfunction in Parkinson's Disease

Dysregulation of mitochondrial dynamics is a key contributor to the pathogenesis of Parkinson's disease (PD). Aberrant mitochondrial fission induced by dynamin-related protein 1 (DRP1) causes mitochondrial dysfunction in dopaminergic (DA) neurons. However, the mechanism of DRP1 activation and its role in PD progression remain unclear. In this study, Mass spectrometry analysis is performed and identified a significant increased DRP1 acetylation at lysine residue 711 (K711) in the mitochondria under oxidative stress. Enhanced DRP1K711 acetylation facilitated DRP1 oligomerization, thereby exacerbating mitochondrial fragmentation and compromising the mitochondrial function. DRP1K711 acetylation also affects mitochondrial DRP1 recruitment and fission independent of canonical S616 phosphorylation. Further analysis reveals the critical role of sirtuin (SIRT)-3 in deacetylating DRP1K711, thereby regulating mitochondrial dynamics and function. SIRT3 agonists significantly inhibit DRP1K711 acetylation, rescue DA neuronal loss, and improve motor function in a PD mouse model. Conversely, selective knockout of SIRT3 in DA neurons exacerbates DRP1K711 acetylation, leading to increased DA neuronal damage, neuronal death, and worsened motor dysfunction. Notably, this study identifies a novel mechanism involving aberrant SIRT3-mediated DRP1 acetylation at K711 as a key driver of mitochondrial dysfunction and DA neuronal death in PD, revealing a potential target for PD treatment.

Mitophagy in Brain Injuries: Mechanisms, Roles, and Therapeutic Potential

Mitophagy is an intracellular degradation pathway crucial for clearing damaged or dysfunctional mitochondria, thereby maintaining cellular homeostasis and responding to various brain injuries. By promptly removing damaged mitochondria, mitophagy protects cells from further harm and support cellular repair and recovery after injury. In different types of brain injury, mitophagy plays complex and critical roles, from regulating the balance between cell death and survival to influencing neurological recovery. This review aims to deeply explore the role and mechanism of mitophagy in the context of brain injuries and uncover how mitophagy regulates the brain response to injury and its potential therapeutic significance. It emphasizes mitophagy's potential in treating brain injuries, including reducing cell damage, promoting cell recovery, and improving neurological function, thus opening new perspectives and directions for future research and clinical applications.

Post-translational acylation of proteins in cardiac hypertrophy

Acylations are post-translational modifications in which functional groups are attached to amino acids on proteins. Most acylations (acetylation, butyrylation, crotonylation, lactylation, malonylation, propionylation and succinylation) involve lysine but cysteine (palmitoylation) and glycine (myristoylation) residues can also be altered. Acylations have important roles in physiological and pathophysiological processes, including cardiac hypertrophy and related cardiovascular diseases. These post-translational modifications influence chromatin architecture, transcriptional regulation and metabolic pathways, thereby affecting cardiomyocyte function and pathology. The dynamic interaction between these acylations and their regulatory enzymes, such as histone acetyltransferases, histone deacetylases and sirtuins, underscores the complexity of cellular homeostasis and pathological processes. Emerging evidence highlights the therapeutic potential of targeting acylations to modulate enzyme activity and metabolite levels, offering promising avenues for novel treatments. In this Review, we explore the diverse mechanisms through which acylations contribute to cardiac hypertrophy, highlighting the complexity and potential therapeutic targets in this regulatory network.

SENP1-SIRT3 axis mediates glycolytic reprogramming to suppress inflammation during Listeria monocytogenes infection

Listeria monocytogenes, a foodborne pathogen, has the ability to invade intestinal mucosal cells, undergo intracellular proliferation, activate host immune responses, and induce diseases such as colitis. We have demonstrated that sentrin-specific protease 1 (SENP1) functions as a protective gene in the host, suppressing the inflammatory response triggered by Listeria monocytogenes. The host's SENP1-SIRT3 axis plays a critical role in regulating inflammation during Listeria monocytogenes infection. Our findings reveal that overexpression of SENP1, particularly under Listeria monocytogenes infection conditions (MOI = 20), effectively suppresses inflammation through modulation of glycolysis. Mechanistically, during Listeria monocytogenes infection, SENP1 accumulates in the mitochondria, facilitating the de-SUMOylation and activation of sirtuin 3 (SIRT3). Activated SIRT3 then regulates the deacetylation of pyruvate kinase M2 (PKM2), leading to a decrease in glycolytic intermediates, downregulation of glycolysis-related gene expression, and suppression of inflammation. Taken together, our study provides a deeper understanding of the mechanistic role of the SENP1-SIRT3 axis in the regulation of inflammation, offering novel insights, and strategies for the treatment and prevention of inflammatory diseases.

IMPORTANCE

Sentrin-specific protease 1 (SENP1)-sirtuin 3 (SIRT3) has never been reported in the regulation of bacteria-induced inflammation. Our study demonstrated that SENP1 acted as a protective factor against Listeria-induced inflammation by promoting SIRT3 activation and subsequent metabolic reprogramming. The SENP1-SIRT3 axis served not only as an essential signaling pathway for regulating mitochondrial metabolic responses to metabolic stress but also responds to bacterial invasion and plays a protective role in the organism. Our findings provide a basis for further research into targeting the SENP1-SIRT3 signaling pathway for the treatment of bacterial infections.

Mitochondrial Dysfunction in HFpEF: Potential Interventions Through Exercise

HFpEF is a prevalent and complex type of heart failure. The concurrent presence of conditions such as obesity, hypertension, hyperglycemia, and hyperlipidemia significantly increase the risk of developing HFpEF. Mitochondria, often referred to as the powerhouses of the cell, are crucial in maintaining cellular functions, including ATP production, intracellular Ca2+ regulation, reactive oxygen species generation and clearance, and the regulation of apoptosis. Exercise plays a vital role in preserving mitochondrial homeostasis, thereby protecting the cardiovascular system from acute stress, and is a fundamental component in maintaining cardiovascular health. In this study, we review the mitochondrial dysfunction underlying the development and progression of HFpEF. Given the pivotal role of exercise in modulating cardiovascular diseases, we particularly focus on exercise as a potential therapeutic strategy for improving mitochondrial function. Graphical abstract Note: This picture was created with BioRender.com.

Sirtuins and Gut Microbiota: Dynamics in Health and a Journey from Metabolic Dysfunction to Hepatocellular Carcinoma

Metabolic dysfunction leading to non-alcoholic fatty liver disease (NAFLD) exhibits distinct molecular and immune signatures that are influenced by factors like gut microbiota. The gut microbiome interacts with the liver via a bidirectional relationship with the gut-liver axis. Microbial metabolites, sirtuins, and immune responses are pivotal in different metabolic diseases. This extensive review explores the complex and multifaceted interrelationship between sirtuins and gut microbiota, highlighting their importance in health and disease, particularly metabolic dysfunction and hepatocellular carcinoma (HCC). Sirtuins (SIRTs), classified as a group of NAD+-dependent deacetylases, serve as crucial modulators of a wide spectrum of cellular functions, including metabolic pathways, the inflammatory response, and the process of senescence. Their subcellular localization and diverse functions link them to various health conditions, including NAFLD and cancer. Concurrently, the gut microbiota, comprising diverse microorganisms, significantly influences host metabolism and immune responses. Recent findings indicate that sirtuins modulate gut microbiota composition and function, while the microbiota can affect sirtuin activity. This bidirectional relationship is particularly relevant in metabolic disorders, where dysbiosis contributes to disease progression. The review highlights recent findings on the roles of specific sirtuins in maintaining gut health and their implications in metabolic dysfunction and HCC development. Understanding these interactions offers potential therapeutic avenues for managing diseases linked to metabolic dysregulation and liver pathology.

Chlorogenic acid targets SIRT6 to relieve UVB - induced UV damage

Skin photoaging, one of the most critical types of exogenous skin aging, occurs when the skin is exposed to excessive ultraviolet radiation, leading to a series of skin-aging problems. The objective of this study was to utilize keratinocytes (HaCaT) treated with medium wave ultraviolet (UVB) as a photoaging model to investigate the anti-photoaging activity of chlorogenic acid (CGA) and preliminarily elucidate its underlying mechanism. The crystal violet assay shows that both 100 and 150 µM of CGA can significantly suppress the cell damage induced by 21.6 mJ/cm² UVB. Furthermore, the results of comet electrophoresis and Western Blot (WB) experiments demonstrate that CGA and OSS-128,167 (SIRT6 inhibitor) can effectively inhibit DNA damage caused by UVB, thereby alleviating cell apoptosis. The co-immunoprecipitation (CO-IP) and WB results suggest that CGA and OSS-128,167 can effectively suppress the activity and expression of the deacetylase of SIRT6, thus enhancing the expression of DDB2 and activating the nucleotide excision repair (NER) of cells to achieve the anti-photoaging effect. The aforementioned results imply that CGA activates NER repair and protects cells from UVB-induced damage by inhibiting the deacetylation activity of SIRT6 and subsequently decreasing the deacetylation modification of DDB2. The study elucidates the molecular mechanisms underlying the beneficial effects of CGA on skin photoaging and establishes a theoretical basis for the development of CGA based sunscreen formulations.

Role of Protein Lysine Acetylation in the Pathogenesis and Treatment of Obesity and Metabolic Syndrome

PURPOSE OF REVIEW

This review aimed to highlight the known role of histone deacetylases (HDACs) and lysine acetyltransferases (KATs) in individuals with obesity, better understand the role of HDACs and KATs enzymes in obesity and related metabolic disorders.

RECENT FINDINGS

Numerous cellular activities, including DNA replication, DNA repair, cell cycle regulation, RNA splicing, signal transmission, metabolic function, protein stability, transportation, and transcriptional regulation, are influenced by lysine acetylation. Protein lysine acetylation serves several purposes, which not only contribute to the development of metabolic disorders linked to obesity but also hold promise for therapeutic approaches. The current study demonstrates that HDACs and KATs control lysine acetylation. This review details the advancements made in the study of obesity, related metabolic diseases, and protein lysine acetylation. It contributes to our understanding of the function and mechanism of protein lysine acetylation in obesity and MS and offers a fresh method for treating these diseases.

Mitochondrial ROS-associated integrated stress response is involved in arsenic-induced blood-testis barrier disruption and protective effect of melatonin

Arsenic (As) is an environmental metalloid. Previous studies have demonstrated that As exposure resulted in decline of sperm quality. This study aimed to investigate the impact of exposure to As on blood-testis barrier (BTB) in a mouse model. Four-week-old male mice were exposed to NaAsO2 (1 or 15 mg/L) for 6 weeks. Our results found that NaAsO2 exposure disrupted the BTB and reduced sperm counts in adult mice. NaAsO2 activated the integrated stress response (ISR) and downregulated barrier junction protein in mouse testes and Sertoli cells. Ribosome profiling sequencing (Ribo-seq) and Ribosome-nascent chain complex-bound mRNA qPCR (RNC-qPCR) showed that translational efficiency of N-cadherin and ZO-1, two key barrier junction proteins, was reduced in NaAsO2-treated Sertoli cells. Mechanistically, NaAsO2 exposure reduced SIRT3 protein via proteasomal degradation, thereby resulting in mitochondrial dysfunction and excess mitochondrial ROS (mtROS) generation in Sertoli cells. Melatonin alleviated NaAsO2-induced mitochondrial dysfunction and mtROS upregulation via reducing SOD2 acetylation in Sertoli cells. Moreover, melatonin antagonized NaAsO2-induced ISR, barrier junction proteins downregulation and barrier function impairment in Sertoli cells. Accordingly, melatonin attenuated NaAsO2-evoked BTB disruption and sperm count reduction in adult mice. These results suggest that mitochondrial dysfunction-associated translational inhibition of barrier junction proteins is involved in As-mediated BTB disruption and sperm quality decline.

m7G-modified mt-tRF3b-LeuTAA regulates mitophagy and metabolic reprogramming via SUMOylation of SIRT3 in chondrocytes

N7-methylguanosine (m7G) modification is one of the most prevalent RNA modifications, and methyltransferase-like protein-1 (METTL1) is a key component of the m7G methyltransferase complex. METTL1-catalyzed m7G as a new RNA modification pathway that regulates RNA structure, biogenesis, and cell migration. Increasing evidence indicates that m7G modification has been implicated in the pathophysiological process of osteoarthritis (OA). However, the underlying molecular mechanisms of m7G modification remains incompletely elucidated during the progression of OA. Here we found that METTL1 and m7G levels were markedly increased in OA chondrocytes. In addition, METTL1-mediated m7G modification upregulated mt-tRF3b-LeuTAA expression to exacerbate chondrocyte degeneration. Mechanistically, mt-tRF3b-LeuTAA decreased the SUMO-specific protease 1 (SENP1) protein expression and upregulated the level of sirtuin 3 (SIRT3) SUMOylation to inhibit PTEN induced kinase 1 (PINK1)/Parkin-mediated mitochondrial mitophagy. Intra-articular injection of PMC-tRF3b-LeuTAA inhibitor (Polyamidoamine-polyethylene glycol surface-modified with Minimal self-peptides and Chondrocyte-affinity peptides, PMC) attenuated destabilization of the medial meniscus (DMM) mouse cartilage degeneration in vivo. Our study demonstrates that METTL1/m7G/mt-tRF3b-LeuTAA axis accelerate cartilage degradation by inhibiting mitophagy and promoting mitochondrial dysfunction through SIRT3 SUMOylation, and suggest that targeting METTL1 and its downstream signaling axis could be a promising therapeutic target for OA treatment.

New insights into the relationship of mitochondrial metabolism and atherosclerosis

Atherosclerotic cardiovascular and cerebrovascular diseases are the number one killer of human health. In view of the important role of mitochondria in the formation and evolution of atherosclerosis, our manuscript aims to comprehensively elaborate the relationship between mitochondria and the formation and evolution of atherosclerosis from the aspects of mitochondrial dynamics, mitochondria-organelle interaction (communication), mitochondria and cell death, mitochondria and vascular smooth muscle cell phenotypic switch, etc., which is combined with genome, transcriptome and proteome, in order to provide new ideas for the pathogenesis of atherosclerosis and the diagnosis and treatment of related diseases.

AdipoRon ameliorates chronic ethanol induced cardiac necroptosis by reducing ceramide mediated mtROS

Chronic ethanol (EtOH) consumption has been widely recognized as a significant contributor to cardiotoxicity. However, no specific treatment is currently available to ameliorate chronic ethanol induced cardiotoxicity. Adiponectin receptor agonist AdipoRon exerts protective effects in multiple organs through alleviating lipotoxicity. Our previous study showed that chronic ethanol consumption increased de novo ceramide synthesis and necroptosis in myocardium. In this study, we investigated the role of AdipoRon on ceramide metabolism and necroptosis in chronic ethanol-treated myocardium. Eight-week-old C57/BL6J mice were fed with a Lieber-Decarli diet containing vehicle or AdipoRon for 12 weeks. Cardiac function, histology and oxidative stress were assessed. We found that chronic ethanol treatment decreased expression of AdipoR2 in myocardium and H9c2 cells, whereas AdipoRon improved cardiac function, reduced myocardium ceramide levels and suppressed necroptosis. By pharmacological interventions, RNA interference and point mutations in AdipoR2, we demonstrated that AdipoRon reduced ceramide levels through PPARα mediated lipid metabolism rather than AdipoR2's ceramidase activity. Using transmission electron microscope and reactive oxygen species (ROS) staining, we showed that chronic ethanol induced myocardium mitochondria damage and mitochondrial reactive oxygen species (mtROS) accumulation. Meanwhile, we found that AdipoRon ameliorated chronic ethanol induced cardiac necroptosis via the SIRT3-SOD2-mtROS pathway. Moreover, C6 ceramide treatment recapitulated chronic ethanol in inducing mtROS and necroptosis, whereas the ceramide synthesis inhibitors myriocin (MYR) and fumonisin B1 (FB1) attenuated chronic ethanol induced mtROS and necroptosis. Collectively, AdipoRon ameliorates chronic ethanol induced cardiac necroptosis by reducing ceramide de novo synthesis and mtROS, which highlights the therapeutic potential of targeting ceramide metabolism and oxidative stress pathways in treating ethanol induced cardiotoxicity.

Nicotinamide adenine dinucleotide rejuvenates septic bone marrow mesenchymal stem cells

BACKGROUND

Sepsis is a severe illness characterized by systemic and multiorgan reactive responses and damage. However, the impact of sepsis on the bone marrow, particularly on bone marrow mesenchymal stem cells (BMSCs), is less reported. BMSCs are critical stromal cells in the bone marrow microenvironment that maintain bone stability and hematopoietic homeostasis; however, the impairment caused by sepsis remains unknown.

AIM

To investigate the effects of sepsis on BMSCs and the underlying mechanisms.

METHODS

BMSCs were obtained from healthy donors and patients with sepsis. We compared the self-renewal capacity, differentiation potential, and hematopoietic supportive ability in vitro. Senescence of septic BMSCs was assessed using β-galactosidase staining, senescence-associated secretory phenotype, intracellular reactive oxygen species levels, and the expression of P16 and P21. Finally, the changes in septic BMSCs after nicotinamide adenine dinucleotide (NAD) treatment were evaluated.

RESULTS

Septic BMSCs showed decreased proliferation and self-renewal, bias towards adipogenic differentiation, and weakened osteogenic differentiation. Additionally, hematopoietic supportive capacity declines in sepsis. The levels of aging markers were significantly higher in the septic BMSCs. After NAD treatment, the proliferation capacity of septic BMSCs showed a recovery trend, with increased osteogenic and hematopoietic supportive capacities. Sepsis resulted in decreased expression of sirtuin 3 (SIRT3) in BMSCs, whereas NAD treatment restored SIRT3 expression, enhanced superoxide dismutase enzyme activity, reduced intracellular reactive oxygen species levels, maintained mitochondrial stability and function, and ultimately rejuvenated septic BMSCs.

CONCLUSION

Sepsis accelerates the aging of BMSCs, as evidenced by a decline in self-renewal and osteogenic capabilities, as well as weakened hematopoietic support functions. These deficiencies can be effectively reversed via the NAD/SIRT3/superoxide dismutase pathway.

Wen-Shen-Tong-Luo-Zhi-Tong-Decoction inhibits bone loss in senile osteoporosis model mice by promoting testosterone production

ETHNOPHARMACOLOGICAL RELEVANCE

Wen-Shen-Tong-Luo-Zhi-Tong-Decoction (WSTLZTD) is a traditional Chinese medicine formula, and its effectiveness in the treatment of senile osteoporosis(SOP) has been confirmed by clinical studies. However, the underlying mechanism of WSTLZTD in SOP is unclear.

AIM OF THE STUDY

This study aimed to clarify the unique effects of Wen-Shen-Tong-Luo-Zhi-Tong-Decoction(WSTLZTD) on senile osteoporosis(SOP) and its underlying mechanisms.

MATERIALS AND METHODS

SAMP6 mice were treated with varying doses of WSTLZTD as the SOP model. Bone loss was evaluated by micro-CT, HE, OCN immunohistochemistry staining, and serum Trap level. Metabolomics studies serum metabolites. ELISA, qPCR, and immunofluorescence were utilized to measure testosterone levels in mouse testis. The effect of testosterone on the mitochondrial energy metabolism of BMSCs was investigated using ROS generation, NAD+/NADH ratio, and WB. Cell senescence was examined by β-galactosidase staining and WB. The effect of TM3 cell conditioned media (CM) on mitochondrial energy metabolism and BMSCs osteogenesis were studied using ALP, ARS, ROS staining, the NAD+/NADH, and WB.

RESULTS

WSTLZTD effectively reversed bone loss in SOP model mice, resulting in better bone microstructure, increased BMD, BV/TV, Tb.n, Tb.Th and, and decreased Tb.Sp. WSTLZTD can increase OCN expression and decrease Trap levels. Network pharmacology data suggest that WSTLZTD regulates steroid hormone production, cellular senescence, inflammation. Metabolomic data indicate that WSTLZTD increases testosterone production or metabolism-related metabolites. WSTLZTD enhanced testosterone production and the mRNA expression of genes involved in testosterone synthesis. Testosterone inhibited the decline in osteogenic differentiation and mitochondrial energy metabolism of senescent BMSCs. The decreased testosterone production in senescent TM3 is reversed by WSTLZTD. CM derived from WSTLZTD-treated TM3 cells promoted osteogenic differentiation and mitochondrial energy metabolism of BMSCs.

CONCLUSIONS

By increasing testosterone production, WSTLZTD may promote mitochondrial energy metabolism and osteogenic differentiation of senescent BMSCs, thereby exerting its anti-SOP effect.

Salvianolic acid B alleviated myocardial ischemia-reperfusion injury via modulating SIRT3-mediated crosstalk between mitochondrial ROS and NLRP3

BACKGROUND

Mitochondrial ROS (mtROS) accumulation and NLRP3 inflammasome activation are critical in the pathogenesis of myocardial ischemia-reperfusion injury (MIRI). However, their upstream regulatory mechanisms and interaction remain inadequately understood.

PURPOSE

The study aims to investigate the therapeutic effect of Salvianolic acid B (Sal B) on MIRI and elucidate its potential molecular mechanism, mainly focusing on the role of SIRT3.

METHODS

SIRT3 was knocked down (SIRT3KD) and overexpressed (SIRT3OE) using small interfering RNA and plasmid, respectively. The role of SIRT3 in the cardioprotective effect of Sal B was explored using MIRI rat models and H9c2 cell hypoxia/reoxygenation (H/R) models. SIRT3, NLRP3 inflammasome proteins, and MnSOD expression were analyzed by Western blot and immunofluorescence staining. MtROS levels were assessed with mitochondrial superoxide indicators (MitoSOX™ Red). ELISA was utilized to measure the levels of LDH, CK-MB, cTnT, and markers of inflammation and oxidative stress. The interaction between SIRT3 and Sal B was studied through biolayer interferometry, cellular thermal shift assay and molecular docking.

RESULTS

Our findings revealed significantly decreased SIRT3 level, enhanced MnSOD acetylation, and activated NLRP3 inflammasome in myocardium after MIRI and H9c2 cardiomyocytes exposed to H/R conditions. SIRT3KD promoted MnSOD acetylation and NLRP3 expression, aggravating mtROS accumulation and inflammation. Conversely, SIRT3OE significantly inhibited MnSOD acetylation and NLRP3 inflammasome activation. In vitro studies confirmed the crosstalk between mtROS and NLRP3, demonstrating that mtROS scavenger inhibited NLRP3 inflammasome activation induced by H/R and SIRT3KD, and the NLRP3 inhibitor suppressed MnSOD acetylation in H/R and SIRT3KD cardiomyocytes. Interestingly, Sal B was found to bind and upregulate SIRT3, reduce the expression of Acy-MnSOD, NLRP3, ASC, Caspase-1, and GSDMD, inhibit oxidative stress and inflammatory response, decrease myocardial infarct size and ST-segment elevation, and restore myocardial morphology. However, the protective effect of Sal B against MIRI was nullified by a specific SIRT3 inhibitor.

CONCLUSION

This study unveils that the SIRT3-mediated interplay between mtROS and the NLRP3 inflammasome is pivotal in the pathogenesis of MIRI. Furthermore, it highlights Sal B as a novel therapeutic agent that alleviates MIRI by targeting SIRT3, offering new insights into MIRI treatment.

SENP1 prevents high fat diet-induced non-alcoholic fatty liver diseases by regulating mitochondrial dynamics

Mitochondrial dynamics plays a crucial role in the occurrence and development of non-alcoholic fatty liver diseases (NAFLD). SENP1, a SUMO-specific protease, catalyzes protein de-SUMOylation and involves in various physiological and pathological processes. However, the exact role of SENP1 in NAFLD remains unclear. Therefore, we investigated the regulatory role of SENP1 in mitochondrial dynamics during the progression of NAFLD. In the study, the NAFLD in vivo model induced by high fat diet (HFD) and in vitro model induced by free fatty acids (FFA) were established to investigate the role and underlying mechanism of SENP1 through detecting mitochondrial morphology and dynamics. Our results showed that the down-regulation of SENP1 expression and the mitochondrial dynamics dysregulation occurred in the NAFLD, evidenced as mitochondrial fragmentation, up-regulation of p-Drp1 ser616 and down-regulation of MFN2, OPA1. However, over-expression of SENP1 significantly alleviated the NAFLD, rectified the mitochondrial dynamics disorder, reduced Cyt-c release and ROS levels induced by FFA or HFD; moreover, the over-expression of SENP1 also reduced the SUMOylation levels of Drp1 and prevented the Drp1 translocation to mitochondria. Our findings suggest that the possible mechanisms of SENP1 were through rectifying the mitochondrial dynamics disorder, reducing Cyt-c release and ROS-mediated oxidative stress. The findings would provide a novel target for the prevention and treatment of NALFD.

Epigenetic modifications and emerging therapeutic targets in cardiovascular aging and diseases

The complex mechanisms underlying the development of cardiovascular diseases remain not fully elucidated. Epigenetics, which modulates gene expression without DNA sequence changes, is shedding light on these mechanisms and their heritable effects. This review focus on epigenetic regulation in cardiovascular aging and diseases, detailing specific epigenetic enzymes such as DNA methyltransferases (DNMTs), histone acetyltransferases (HATs), and histone deacetylases (HDACs), which serve as writers or erasers that modify the epigenetic landscape. We also discuss the readers of these modifications, such as the 5-methylcytosine binding domain proteins, and the erasers ten-eleven translocation (TET) proteins. The emerging role of RNA methylation, particularly N6-methyladenosine (m6A), in cardiovascular pathogenesis is also discussed. We summarize potential therapeutic targets, such as key enzymes and their inhibitors, including DNMT inhibitors like 5-azacytidine and decitabine, HDAC inhibitors like belinostat and givinotide, some of which have been approved by the FDA for various malignancies, suggesting their potential in treating cardiovascular diseases. Furthermore, we highlight the role of novel histone modifications and their associated enzymes, which are emerging as potential therapeutic targets in cardiovascular diseases. Thus, by incorporating the recent studies involving patients with cardiovascular aging and diseases, we aim to provide a more detailed and updated review that reflects the advancements in the field of epigenetic modification in cardiovascular diseases.

Baicalin Attenuates Diabetic Cardiomyopathy In Vivo and In Vitro by Inhibiting Autophagy and Cell Death Through SENP1/SIRT3 Signaling Pathway Activation

Aims: Diabetic heart damage can lead to cardiomyocyte death, which endangers human health. Baicalin (BAI) is a bioactive compound that plays an important role in cardiovascular diseases. Sentrin/SUMO-specific protease 1 (SENP1) regulates the de-small ubiquitin-like modifier (deSUMOylation) process of Sirtuin 3 (SIRT3) and plays a crucial role in regulating mitochondrial mass and preventing cell injury. Our hypothesis is that BAI regulates the deSUMOylation level of SIRT3 through SENP1 to enhance mitochondrial quality control and prevent cell death, ultimately improving diabetic cardiomyopathy (DCM). Results: The protein expression of SENP1 decreased in cardiomyocytes induced by high glucose and in db/db mice. The cardioprotective effects of BAI were eliminated by silencing endogenous SENP1, whereas overexpression of SENP1 showed similar cardioprotective effects to those of BAI. Furthermore, co-immunoprecipitation experiments showed that BAI's cardioprotective effect was due to the inhibition of the SUMOylation modification level of SIRT3 by SENP1. Inhibition of SENP1 expression resulted in an increase in SUMOylation of SIRT3. This led to increased acetylation of mitochondrial protein, accumulation of reactive oxygen species, impaired autophagy, impaired mitochondrial oxidative phosphorylation, and increased cell death. None of these changes could be reversed by BAI. Conclusion: BAI improves DCM by promoting SIRT3 deSUMOylation through SENP1, restoring mitochondrial stability, and preventing the cell death of cardiomyocytes. Innovation: This study proposes for the first time that SIRT3 SUMOylation modification is involved in the development of DCM and provides in vivo and in vitro data support that BAI inhibits cardiomyocyte ferroptosis and apoptosis in DCM through SENP1. Antioxid. Redox Signal. 42, 53-76.

Multi-omics analysis reveals the genetic aging landscape of Parkinson's disease

Parkinson's disease (PD) is the second most common age-related neurodegenerative disease after Alzheimer's disease. Despite numerous studies, specific age-related factors remain unidentified. This study employed a multi-omics approach to investigate the link between PD and aging. We integrated blood gene expression profiles, expression quantitative trait loci, genome-wide association studies, predictive models, and conducted clinical validation.By analyzing PD datasets, a total of 953 differentially expressed genes (DEGs) and 10 intersecting aging differentially expressed genes (ADEGs) were identified. Enrichment analysis revealed that the regulatory pathways of these ADEGs involve the classical Wnt signaling pathway, endoplasmic reticulum stress, and neuronal apoptosis. Mendelian randomization (MR) analysis showed that the MAP3K5 gene significantly reduces the risk of PD. Multivariate regression analysis identified MXD1, CREB1, and SIRT3 as key diagnostic genes and constructed a predictive model to aid clinical decision-making. Enzyme-linked immunosorbent assay experiments validated the expression levels of these genes in the serum of PD patients.This study utilized a multi-omics approach to identify key ADEGs and their regulatory mechanisms in PD, leading to the establishment of a diagnostic model. The resource is accessible at this link: https://yunhaihupo.shinyapps.io/DynNomapp . This web application can be used as a standalone resource to explore changes in blood transcription profiles in PD and their relationship to clinical and aging aspects, generating new research hypotheses.

The Mitochondrial Blueprint: Unlocking Secondary Metabolite Production

Mitochondrial metabolism plays a pivotal role in regulating the synthesis of secondary metabolites, which are crucial for the survival and adaptation of organisms. These metabolites are synthesized during specific growth stages or in response to environmental stress, reflecting the organism's ability to adapt to changing conditions. Mitochondria, while primarily known for their role in energy production, directly regulate secondary metabolite biosynthesis by providing essential precursor molecules, energy, and reducing equivalents necessary for metabolic reactions. Furthermore, they indirectly influence secondary metabolism through intricate signaling pathways, including reactive oxygen species (ROS), metabolites, and redox signaling, which modulate various metabolic processes. This review explores recent advances in understanding the molecular mechanisms governing mitochondrial metabolism and their regulatory roles in secondary metabolite biosynthesis, which highlights the involvement of transcription factors, small RNAs, and post-translational mitochondrial modifications in shaping these processes. By integrating current insights, it aims to inspire future research into mitochondrial regulatory mechanisms in Arabidopsis thaliana, Solanum tuberosum, Nicotiana tabacum, and others that may enhance their secondary metabolite production. A deeper understanding of the roles of mitochondria in secondary metabolism could contribute to the development of new approaches in biotechnology applications.

SENP1 promotes deacetylation of isocitrate dehydrogenase 2 to inhibit ferroptosis of breast cancer via enhancing SIRT3 stability

Breast cancer, one of the most prevalent malignant tumors in women worldwide, is characterized by a poor prognosis and high susceptibility to recurrence and metastasis. Ferroptosis, a lipid peroxide-dependent programed cell death pathway, holds significant potential for breast cancer treatment. Therefore, investigating the regulatory targets and associated mechanisms of ferroptosis is crucial. In this study, we conducted proteomic screening and identified isocitrate dehydrogenase 2 (IDH2) as an important player in breast cancer progression. Our findings were further supported by CCK-8 assays, transwell experiments, and scratch assays, which demonstrated that the elevated expression of IDH2 promotes breast cancer progression. Through both in vitro and in vivo experiments along with the erastin treatment, we discovered that increased expression of IDH2 confers resistance to ferroptosis in breast cancer cells. By employing Western blot analysis, Co-IP techniques, and immunofluorescence staining methods, we elucidated the upstream molecular mechanism involving SENP1-mediated SIRT3 de-SUMOylatase, which enhances IDH2 enzyme activity through deacetylation, thereby regulating cell ferroptosis. In conclusion, our study highlights the role of the SENP1-SIRT3 axis in modulating ferroptosis via IDH2 in breast cancer cells, providing valuable insights for developing targeted therapies aimed at enhancing ferroptosis for improved management of breast cancer.

Staphylococcus aureus Conquers Host by Hijacking Mitochondria via PFKFB3 in Epithelial Cells

Staphylococcus aureus persists within mammary epithelial cells for an extended duration, exploiting the host metabolic resources to facilitate replication. This study revealed a mechanism by which intracellular S aureus reprograms host metabolism, with PFKFB3 playing a crucial role in this process. Mechanistically, S aureus induced mitochondrial damage, leading to increased levels of mitochondrial reactive oxygen species and dysfunction in the electron transport chain. Moreover, S aureus shifted the balance of mitochondrial dynamics from fusion to fission, subsequently activating PINK1-PRKN-dependent mitophagy, causing loss of sirtuin 3 to stabilize hypoxic inducible factor 1α, and shifting the host metabolism toward enhanced glycolysis. The inhibition of PFKFB3 reversed the mitochondrial damage and degradation of sirtuin 3 induced by S aureus. Overall, our findings elucidate the mechanism by which S aureus reprograms host metabolism, thereby offering insights into the treatment of S aureus infection.

The Expression of SIRT3 in Endometrial Carcinoma and Its Effect on Promoting Apoptosis of Ishikawa Cells

Endometrial cancer (EC) is one of the three most common malignancies of the female reproductive system. SIRT3 is an NAD+-dependent protein deacetylase that maintains the stability of the intracellular environment. This study aims to investigate the mechanism of SIRT3 in regulating apoptosis in endometrial cancer and further reveal the role of SIRT3 in endometrial cancer. Differential expression of SIRT3 in tumors was analyzed by GEPIA using TCGA database data. Meanwhile, mRNA and protein expression levels of SIRT3 in tissues and cells were examined using RT-qPCR, Western Blot, and immunohistochemistry. The expression of SIRT3 after estradiol (E2) stimulation of Ishikawa cells was detected using RT-qPCR and Western Blot techniques. The effect of transfection after SIRT3 knockdown and overexpression was verified using RT-qPCR and Western Blot. Flow cytometry and TUNEL assay were used to detect the effect of SIRT3 on apoptosis. Reactive oxygen species (ROS) was used to detect the effect of SIRT3 on the level of oxidative stress in cells. The expression of apoptotic protein (BAX, cleaved-Caspase 3) and autophagy protein (cyto C and LC3A) were detected in transfected Ishikawa cell. Differences analysis of TCGA database data showed that the expression of SIRT3 in EC was significantly lower than that in normal endometrial tissue. The mRNA and protein levels of SIRT3 were significantly lower in EC tissues or cells than normal controls. E2 stimulation in Ishikawa cells resulted in the down-regulation of SIRT3 expression. After transfection, SIRT3 promoted the apoptosis of Ishikawa cells and attenuated the levels of ROS. Overexpression of SIRT3 promoted apoptosis and autophagy-related proteins. Thus, high expression of SIRT3 inhibits the development of EC whereas low expression of SIRT3 may promote the progression of EC, which provides a new direction for studying the treatment of EC.

New insights into SUMOylation and NEDDylation in fibrosis

Fibrosis is the outcome of any abnormal tissue repair process that results in normal tissue replacement with scar tissue, leading to persistent tissue damage and cellular injury. During the process of fibrosis, many cytokines and chemokines are involved, and their activities are controlled by post-translational modifications, especially SUMOylation and NEDDylation. Both these modifications entail a three-step process of activation, conjugation, and ligation that involves three kinds of enzymes, namely, E1 activating, E2 conjugating, and E3 ligase enzymes. SUMOylation participates in organ fibrosis by modulating FXR, PML, TGF-β receptor I, Sirt3, HIF-1α, and Sirt1, while NEDDylation influences organ fibrosis by regulating cullin3, NIK, SRSF3, and UBE2M. Further investigations exhibit the therapeutic potentials of SUMOylation/NEDDylation activators and inhibitors against organ fibrosis, especially ginkgolic acid in SUMOylation and MLN4924 in NEDDylation. These results demonstrate the therapeutic effects of SUMOylation and NEDDylation against organ fibrosis and highlight their activators as well as inhibitors as potential candidates. In the future, deeper investigations of SUMOylation and NEDDylation are needed to identify novel substrates against organ fibrosis; moreover, clinical investigations are needed to determine the therapeutic effects of their activators and inhibitors that can benefit patients. This review highlights that SUMOylation and NEDDylation function as potential therapeutic targets for organ fibrosis.

SENP1 Promotes Caspase-11 Inflammasome Activation and Aggravates Inflammatory Response in Murine Acute Lung Injury Induced by Lipopolysaccharide

BACKGROUND

Infection is the leading cause of acute lung injury (ALI). Macrophages, which are pivotal innate immune cells, play a critical role in mediating inflammatory processes. Intracellular lipopolysaccharide (LPS) from invasive Gram-negative bacteria can activate the caspase-11 inflammasome, leading to the induction of pyroptosis in macrophages. This process subsequently triggers the release of inflammatory cytokines and damage-associated molecular patterns from pyroptotic macrophages, thereby exacerbating inflammatory progression in ALI. However, the precise regulatory mechanisms governing caspase-11 activation is still unclear. Sentrin-specific proteases (SENPs) have been identified as notable targets for their anti-inflammatory properties. Nevertheless, the specific role of SENPs in macrophage pyroptosis during the pathogenesis of ALI remains unknown.

METHODS

We used LPS as an endotoxin to induce ALI. We analyzed the expression and location of sentrin-specific protease 1 (SENP1), pulmonary impairment, macrophage infiltration, caspase-11 inflammasome expression and activation, caspase-11 SUMOylation, and inflammatory cytokine secretion.

RESULTS

Upregulated expression of SENP1 in lung tissue and macrophages was observed following LPS stimulation. SENP1 mediates de-SUMOylation and activation of caspase-11 inflammasome in macrophages. Moreover, pharmacological inhibition or genetic deficiency of SENP1 in macrophages significantly improved ALI-related histological damage by reducing the secretion of inflammatory cytokines and suppressing caspase-11-dependent pyroptosis.

CONCLUSIONS

Collectively, our findings highlight the involvement of SENP1 in caspase-11 activation and inflammatory progression in macrophages, thereby establishing a scientific foundation for the exploration of novel therapeutic strategies aimed at treating ALI.

USP14 modulates cell pyroptosis and ameliorates doxorubicin-induced cardiotoxicity by deubiquitinating and stabilizing SIRT3

This study investigates the role of the deubiquitinating enzyme USP14 in alleviating doxorubicin (DOX)-induced cardiotoxicity (DIC), particularly concerning its mechanism of regulating pyroptosis through the stabilization of the mitochondrial protein SIRT3. Using in vivo and in vitro models, the research demonstrated that USP14 overexpression protects against DOX-induced cardiac damage by modulating pyroptosis. Silencing SIRT3 via siRNA revealed that SIRT3 is a key intermediary molecule in USP14-mediated regulation of pyroptosis. Notably, DOX exposure resulted in decreased USP14 expression, while its overexpression preserved mitochondrial function and reduced oxidative stress by stabilizing SIRT3. Immunoprecipitation confirmed that USP14 stabilizes SIRT3 through deubiquitination. These findings position USP14 as a promising therapeutic target for mitigating DOX-induced cardiotoxicity by stabilizing SIRT3 and maintaining mitochondrial integrity, suggesting potential novel strategies for cardio-protection in chemotherapy.

SUMO proteases: from cellular functions to disease

Posttranslational modification by small ubiquitin-like modifiers (SUMOs) is critical in regulating diverse cellular processes including gene expression, cell cycle progression, genome integrity, cellular metabolism, and inflammation and immunity. The covalent attachment of SUMOs to target proteins is highly dynamic and reversible through the concerted action of SUMO conjugating and deconjugating enzymes. In mammalian cells, sentrin-specific proteases (SENPs) are the most abundant family of deconjugating enzymes. This review highlights recent advances in our knowledge of the substrates and cellular and physiological processes controlled by SENPs. Notably, SENPs are emerging as significant players in cancer, as well as in other diseases, making them attractive targets for therapeutic intervention. Consequently, a growing amount of effort in the field is being directed towards the development of SENP inhibitors.

Mitochondrial Dysfunction-Evoked DHODH Acetylation is Involved in Renal Cell Ferroptosis during Cisplatin-Induced Acute Kidney Injury

Several studies have observed renal cell ferroptosis during cisplatin-induced acute kidney injury (AKI). However, the mechanism is not completely clear. In this study, oxidized arachidonic acid (AA) metabolites are increased in cisplatin-treated HK-2 cells. Targeted metabolomics showed that the end product of pyrimidine biosynthesis is decreased and the initiating substrate of pyrimidine biosynthesis is increased in cisplatin-treated mouse kidneys. Mitochondrial DHODH, a key enzyme for pyrimidine synthesis, and its downstream product CoQH2, are downregulated. DHODH overexpression attenuated but DHODH silence exacerbated cisplatin-induced CoQH2 depletion and lipid peroxidation. Mechanistically, renal DHODH acetylation is elevated in cisplatin-exposed mice. Mitochondrial SIRT3 is reduced in cisplatin-treated mouse kidneys and HK-2 cells. Both in vitro SIRT3 overexpression and in vivo NMN supplementation attenuated cisplatin-induced mitochondrial DHODH acetylation and renal cell ferroptosis. By contrast, Sirt3 knockout aggravated cisplatin-induced mitochondrial DHODH acetylation and renal cell ferroptosis, which can not be attenuated by NMN. Additional experiments showed that cisplatin caused mitochondrial dysfunction and SIRT3 SUMOylation. Pretreatment with mitochondria-target antioxidant MitoQ alleviated cisplatin-caused mitochondrial dysfunction, SIRT3 SUMOylation, and DHODH acetylation. MitoQ pretreatment protected against cisplatin-caused AKI and renal cell ferroptosis. Taken together, these results suggest that mitochondrial dysfunction-evoked DHODH acetylation partially contributes to renal cell ferroptosis during cisplatin-induced AKI.

Sirtuin 1/sirtuin 3 are robust lysine delactylases and sirtuin 1-mediated delactylation regulates glycolysis

Lysine lactylation (Kla), an epigenetic mark triggered by lactate during glycolysis, including the Warburg effect, bridges metabolism and gene regulation. Enzymes such as p300 and HDAC1/3 have been pivotal in deciphering the regulatory dynamics of Kla, though questions about additional regulatory enzymes, their specific Kla substrates, and the underlying functional mechanisms persist. Here, we identify SIRT1 and SIRT3 as key "erasers" of Kla, shedding light on their selective regulation of both histone and non-histone proteins. Proteomic analysis in SIRT1/SIRT3 knockout HepG2 cells reveals distinct substrate specificities toward Kla, highlighting their unique roles in cellular signaling. Notably, we highlight the role of specific Kla modifications, such as those on the M2 splice isoform of pyruvate kinase (PKM2), in modulating metabolic pathways and cell proliferation, thereby expanding Kla's recognized functions beyond epigenetics. Therefore, this study deepens our understanding of Kla's functional mechanisms and broadens its biological significance.

Design, synthesis and biological evaluation of novel SIRT3 inhibitors targeting both NAD+ and substrate binding sites for the treatment of acute myeloid leukemia

Acute myeloid leukemia (AML) represents a highly malignant subtype of leukemia with limited therapeutic options. In this study, we propose a novel therapeutic strategy for treating AML by inhibiting SIRT3 to regulate mitochondrial metabolism network involved in energy metabolism and epigenetic modifications essential for AML survival. A series of thieno [3,2-d]pyrimidine-6-carboxamide derivatives were designed and synthesized by structure-based strategy, 17f was documented to be a potent and acceptable selective SIRT3 inhibitor with IC50 value of 0.043 μM and exhibited profound anti-proliferative activity in MOLM13, MV4-11, and HL-60 cells. Through CETSA assay and the degree of deacetylation of intracellular SIRT3 substrates, we confirmed that 17f could effectively bind and inhibit SIRT3 activity in AML cells. Mechanistically, 17f suppressed mitochondrial function, triggered the accumulation of ROS, and significantly inhibited the production of ATP in AML cells. With the breakdown of mitochondrial function, 17f eventually induced apoptosis of AML cells. In addition, 17f also showed excellent anti-AML potential in nude mouse tumor models of HL-60-Luc. Collectively, these results demonstrate that 17f is a potent and acceptable selective SIRT3 inhibitor with promising potential to treat AML.

Nuclear Factor Erythroid 2 Related Factor 2 and Mitochondria Form a Mutually Regulating Circuit in the Prevention and Treatment of Metabolic Syndrome

Significance: Metabolic syndrome (MetS) has become a major global public health problem and there is an urgent need to elucidate its pathogenesis and find more effective targets and modalities for intervention. Recent Advances: Oxidative stress and inflammation are two of the major causes of MetS-related symptoms such as insulin resistance and obesity. Nuclear factor erythroid 2 related factor 2 (Nrf2) is one of the important systems responding to oxidative stress and inflammation. As cells undergo stress, cysteines within Kelch-like ECH-associated protein 1 (Keap1) are oxidized or electrophilically modified, allowing Nrf2 to escape ubiquitination and be translocated from the cytoplasm to the nucleus, facilitating the initiation of the antioxidant transcriptional program. Meanwhile, a growing body of evidence points out a specific modulation of mitochondrial homeostasis by Nrf2. After nuclear translocation, Nrf2 activates downstream genes involved in various aspects of mitochondrial homeostasis, including mitochondrial biogenesis and dynamics, mitophagy, aerobic respiration, and energy metabolism. In turn, mitochondria reciprocally activate Nrf2 by releasing reactive oxygen species and regulating antioxidant enzymes. Critical Issues: In this review, we first summarize the interactions between Nrf2 and mitochondria in the modulation of oxidative stress and inflammation to ameliorate MetS, then propose that Nrf2 and mitochondria form a mutually regulating circuit critical to maintaining homeostasis during MetS. Future Directions: Targeting the Nrf2-mitochondrial circuit may be a promising strategy to ameliorate MetS, such as obesity, diabetes, and cardiovascular diseases.

Glutamine deprivation in glioblastoma stem cells triggers autophagic SIRT3 degradation to epigenetically restrict CD133 expression and stemness

Glioblastoma multiforme (GBM) is a highly malignant brain tumor, and glioblastoma stem cells (GSCs) are the primary cause of GBM heterogeneity, invasiveness, and resistance to therapy. Sirtuin 3 (SIRT3) is mainly localized in the mitochondrial matrix and plays an important role in maintaining GSC stemness through cooperative interaction with the chaperone protein tumor necrosis factor receptor-associated protein 1 (TRAP1) to modulate mitochondrial respiration and oxidative stress. The present study aimed to further elucidate the specific mechanisms by which SIRT3 influences GSC stemness, including whether SIRT3 serves as an autophagy substrate and the mechanism of SIRT3 degradation. We first found that SIRT3 is enriched in CD133+ GSCs. Further experiments revealed that in addition to promoting mitochondrial respiration and reducing oxidative stress, SIRT3 maintains GSC stemness by epigenetically regulating CD133 expression via succinate. More importantly, we found that SIRT3 is degraded through the autophagy-lysosome pathway during GSC differentiation into GBM bulk tumor cells. GSCs are highly dependent on glutamine for survival, and in these cells, we found that glutamine deprivation triggers autophagic SIRT3 degradation to restrict CD133 expression, thereby disrupting the stemness of GSCs. Together our results reveal a novel mechanism by which SIRT3 regulates GSC stemness. We propose that glutamine restriction to trigger autophagic SIRT3 degradation offers a strategy to eliminate GSCs, which combined with other treatment methods may overcome GBM resistance to therapy as well as relapse.

Cellular and molecular biology of posttranslational modifications in cardiovascular disease

Cardiovascular disease (CVD) has now become the leading cause of death worldwide, and its high morbidity and mortality rates pose a great threat to society. Although numerous studies have reported the pathophysiology of CVD, the exact pathogenesis of all types of CVD is not fully understood. Therefore, much more research is still needed to explore the pathogenesis of CVD. With the development of proteomics, many studies have successfully identified the role of posttranslational modifications in the pathogenesis of CVD, including key processes such as apoptosis, cell metabolism, and oxidative stress. In this review, we summarize the progress in the understanding of posttranslational modifications in cardiovascular diseases, including novel protein posttranslational modifications such as succinylation and nitrosylation. Furthermore, we summarize the currently identified histone deacetylase (HDAC) inhibitors used to treat CVD, providing new perspectives on CVD treatment modalities. We critically analyze the roles of posttranslational modifications in the pathogenesis of CVD-related diseases and explore future research directions related to posttranslational modifications in cardiovascular diseases.

Empagliflozin alleviates obesity-related cardiac dysfunction via the activation of SIRT3-mediated autophagosome formation

BACKGROUND

Empagliflozin (EMPA) has demonstrated efficacy in providing cardiovascular benefits in metabolic diseases. However, the direct effect of EMPA on autophagy in obesity-related cardiac dysfunction remains unclear. Therefore, this study aimed to determine changes in cardiac autophagy during diet-induced obesity and clarify the exact mechanism by which EMPA regulates autophagic pathways.

METHODS

Male C57BL/6J mice were fed a 12-week high-fat diet (HFD) followed by 8 weeks of EMPA treatment. Body composition analysis and echocardiography were performed to evaluate metabolic alterations and cardiac function. Histological and immunofluorescence staining was used to evaluate potential enhancements in myocardial structure and biological function. Additionally, H9c2 cells were transfected with small interfering RNA targeting sirtuin 3 (SIRT3) and further treated with palmitic acid (PA) with or without EMPA. Autophagy-related targets were analyzed by western blotting and RT‒qPCR.

RESULTS

EMPA administration effectively ameliorated metabolic disorders and cardiac diastolic dysfunction in HFD-fed mice. EMPA prevented obesity-induced myocardial hypertrophy, fibrosis, and inflammation through the activation of SIRT3-mediated autophagosome formation. The upregulation of SIRT3 triggered by EMPA promoted the initiation of autophagy by activating AMP-activated protein kinase (AMPK) and Beclin1. Furthermore, activated SIRT3 contributed to the elongation of autophagosomes through autophagy-related 4B cysteine peptidase (ATG4B) and autophagy-related 5 (ATG5).

CONCLUSIONS

EMPA promotes SIRT3-mediated autophagosome formation to alleviate damage to the cardiac structure and function of obese mice. Activated SIRT3 initiates autophagy through AMPK/Beclin1 and further stimulates elongation of the autophagosome membrane via ATG4B/ATG5. These results provide a new explanation for the cardioprotective benefits of EMPA in obesity.

Metabolic mechanisms orchestrated by Sirtuin family to modulate inflammatory responses

Maintaining metabolic homeostasis is crucial for cellular and organismal health throughout their lifespans. The intricate link between metabolism and inflammation through immunometabolism is pivotal in maintaining overall health and disease progression. The multifactorial nature of metabolic and inflammatory processes makes study of the relationship between them challenging. Homologs of Saccharomyces cerevisiae silent information regulator 2 protein, known as Sirtuins (SIRTs), have been demonstrated to promote longevity in various organisms. As nicotinamide adenine dinucleotide-dependent deacetylases, members of the Sirtuin family (SIRT1-7) regulate energy metabolism and inflammation. In this review, we provide an extensive analysis of SIRTs involved in regulating key metabolic pathways, including glucose, lipid, and amino acid metabolism. Furthermore, we systematically describe how the SIRTs influence inflammatory responses by modulating metabolic pathways, as well as inflammatory cells, mediators, and pathways. Current research findings on the preferential roles of different SIRTs in metabolic disorders and inflammation underscore the potential of SIRTs as viable pharmacological and therapeutic targets. Future research should focus on the development of promising compounds that target SIRTs, with the aim of enhancing their anti-inflammatory activity by influencing metabolic pathways within inflammatory cells.

The study on the role of O-GlcNAcylation of SIRT3 in regulating mitochondrial oxidative stress during simulate myocardial ischemia-reperfusion

Myocardial ischemia-reperfusion injury (MIRI) is a significant complication following reperfusion therapy after myocardial infarction. Mitochondrial oxidative stress is a critical factor in MIRI, and Sirtuin 3 (SIRT3), as a major mitochondrial deacetylase, plays a key protective role, with its activity potentially regulated by O-GlcNAcylation. This study used the H9C2 cell line to establish a simulated ischemia/reperfusion (SI/R) model, we utilized co-immunoprecipitated to validate the relationship between O-GlcNAc transferase (OGT) and SIRT3, demonstrated SIRT3 O-GlcNAcylation sites through LC-MS/MS, and performed site mutations using CRISPR/Cas9 technology. The results were validated using immunoblotting. SIRT3 and superoxide dismutase 2 (SOD2) activities were detected using a fluorometric assay, while mitochondrial reactive oxygen species (MROS) levels and cellular apoptosis were assessed using immunofluorescence. We have identified an interaction between SIRT3 and OGT, where SIRT3 undergoes dynamic O-GlcNAcylation at the S190 site, facilitating SIRT3 deacetylase activity. During SI/R, elevated levels of O-GlcNAcylation activate SOD2 by promoting SIRT3 enzyme activity, thereby inhibiting excessive MROS production. This significantly mitigates the occurrence of malignant autophagy in myocardial cells during reperfusion, promoting their survival. Conversely, blocking SIRT3 O-GlcNAcylation at the S190 site exacerbates SI/R injury. We demonstrate that O-GlcNAcylation is a crucial post-translational modification (PTM) of SIRT3 during SI/R, shedding light on a promising mechanism for future therapeutic approaches.

Ototoxic Effect of Nicotinamide Riboside

We studied the function of the auditory system in Wistar rats after repeated intravenous administration of nicotinamide riboside (NR). The functional activity of the receptor and retrocochlear parts of the auditory system were assessed by recording short-latency auditory evoked potentials (SLAEPs) and distortion-product otoacoustic emissions (DPOAEs) at baseline, immediately after NR administration, and 1 and 2 months later. Repeated intravenous NR administration (cumulative dose of 2700 mg/kg) to Wistar rats has a detrimental impact on the structures within the cochlear section of the auditory system.

SUMO-specific proteases: SENPs in oxidative stress-related signaling and diseases

Oxidative stress is employed to depict a series of responses detrimental to normal cellular functions resulting from an imbalance between intracellular oxidants, mainly reactive oxygen species and antioxidant defenses. Oxidative stress often contributes to the development of various diseases, including cancer, cardiovascular diseases, and neurodegenerative diseases. In this process, the relationship between small ubiquitin-like modifier (SUMO) and oxidative stress has garnered significant attention, with its posttranslational modification (PTM) frequently serving as a marker of oxidative stress status. Sentrin/SUMO-specific proteases (SENPs), affected by alternative splicing, PTMs such as phosphorylation and ubiquitination, and various protein interactions, are crucial molecules in the SUMO process. The human SENP family has six members (SENP1-3, SENP5-7), which are classified into two categories based on sequence similarity, substrate specificity, and subcellular location. They have two core functions in the human body: first, by cleaving the precursor SUMO and exposing the C-terminal glycine, they initiate the SUMO process; second, they can specifically recognize and dissociate SUMO proteins bound to substrates, a process known as deSUMOylation. However, the connection between deSUMOylation and oxidative stress remains a relatively unexplored area despite their strong association with oxidative diseases such as cancer and cardiovascular disease. This article aims to illustrate the significant contribution of SENPs to the oxidative stress pathway through deSUMOylation by reviewing their structure and classification, their roles in oxidative stress, and the changes in their expression and activity in several typical oxidative stress-related diseases.

SUMOylation at the crossroads of gut health: insights into physiology and pathology

SUMOylation, a post-translational modification involving the covalent attachment of small ubiquitin-like modifier (SUMO) proteins to target substrates, plays a pivotal role at the intersection of gut health and disease, influencing various aspects of intestinal physiology and pathology. This review provides a comprehensive examination of SUMOylation's diverse roles within the gut microenvironment. We examine its critical roles in maintaining epithelial barrier integrity, regulating immune responses, and mediating host-microbe interactions, thereby highlighting the complex molecular mechanisms that underpin gut homeostasis. Furthermore, we explore the impact of SUMOylation dysregulation in various intestinal disorders, including inflammatory bowel diseases and colorectal cancer, highlighting its implications as a potential diagnostic biomarker and therapeutic target. By integrating current research findings, this review offers valuable insights into the dynamic interplay between SUMOylation and gut health, paving the way for novel therapeutic strategies aimed at restoring intestinal equilibrium and combating associated pathologies.

SRF SUMOylation modulates smooth muscle phenotypic switch and vascular remodeling

Serum response factor (SRF) controls gene transcription in vascular smooth muscle cells (VSMCs) and regulates VSMC phenotypic switch from a contractile to a synthetic state, which plays a key role in the pathogenesis of cardiovascular diseases (CVD). It is not known how post-translational SUMOylation regulates the SRF activity in CVD. Here we show that Senp1 deficiency in VSMCs increased SUMOylated SRF and the SRF-ELK complex, leading to augmented vascular remodeling and neointimal formation in mice. Mechanistically, SENP1 deficiency in VSMCs increases SRF SUMOylation at lysine 143, reducing SRF lysosomal localization concomitant with increased nuclear accumulation and switching a contractile phenotype-responsive SRF-myocardin complex to a synthetic phenotype-responsive SRF-ELK1 complex. SUMOylated SRF and phospho-ELK1 are increased in VSMCs from coronary arteries of CVD patients. Importantly, ELK inhibitor AZD6244 prevents the shift from SRF-myocardin to SRF-ELK complex, attenuating VSMC synthetic phenotypes and neointimal formation in Senp1-deficient mice. Therefore, targeting the SRF complex may have a therapeutic potential for the treatment of CVD.

Sirtuin 3 in renal diseases and aging: From mechanisms to potential therapies

The longevity protein sirtuins (SIRTs) belong to a family of nicotinamide adenine dinucleotide (NAD+)-dependent deacetylases. In mammals, SIRTs comprise seven members (SIRT1-7) which are localized to different subcellular compartments. As the most prominent mitochondrial deacetylases, SIRT3 is known to be regulated by various mechanisms and participate in virtually all aspects of mitochondrial homeostasis and metabolism, exerting significant impact on multiple organs. Notably, the kidneys possess an abundance of mitochondria that provide substantial energy for filtration and reabsorption. A growing body of evidence now supports the involvement of SIRT3 in several renal diseases, including acute kidney injury, chronic kidney disease, and diabetic nephropathy; notably, these diseases are all associated with aging. In this review, we summarize the emerging role of SIRT3 in renal diseases and aging, and highlights the intricate mechanisms by which SIRT3 exerts its effects. In addition, we highlight the potential therapeutic significance of modulating SIRT3 and provide valuable insights into the therapeutic role of SIRT3 in renal diseases to facilitate clinical application.

Mitochondrial sirtuin 3 and role of natural compounds: the effect of post-translational modifications on cellular metabolism

Sirtuins (SIRTs) are a family of proteins with enzymatic activity. In particular, they are a family of class III NAD+-dependent histone deacetylases and ADP-ribosyltransferases. NAD+-dependent deac(et)ylase activities catalyzed by sirtuin include ac(et)ylation, propionylation, butyrylation, crotonylation, manylation, and succinylation. Specifically, human SIRT3 is a 399 amino acid protein with two functional domains: a large Rossmann folding motif and NAD+ binding, and a small complex helix and zinc-binding motif. SIRT3 is widely expressed in mitochondria-rich tissues and is involved in maintaining mitochondrial integrity, homeostasis, and function. Moreover, SIRT3 regulates related diseases, such as aging, hepatic, kidney, neurodegenerative and cardiovascular disease, metabolic diseases, and cancer development. In particular, one of the most significant and damaging post-translational modifications is irreversible protein oxidation, i.e. carbonylation. This process is induced explicitly by increased ROS production due to mitochondrial dysfunction. SIRT3 is carbonylated by 4-hydroxynonenal at the level of Cys280. The carbonylation induces conformational changes in the active site, resulting in allosteric inhibition of SIRT3 activity and loss of the ability to deacetylate and regulate antioxidant enzyme activity. Phytochemicals and, in particular, polyphenols, thanks to their strong antioxidant activity, are natural compounds with a positive regulatory action on SIRT3 in various pathologies. Indeed, the enzymatic SIRT3 activity is modulated, for example, by different natural polyphenol classes, including resveratrol and the bergamot polyphenolic fraction. Thus, this review aims to elucidate the mechanisms by which phytochemicals can interact with SIRT3, resulting in post-translational modifications that regulate cellular metabolism.

The protective effects of orexin-A in alleviating cell senescence against interleukin-1β (IL-1β) in chondrocytes

Osteoarthritis (OA) is one of the most important causes of global disability, and dysfunction of chondrocytes is an important risk factor. The treatment of OA is still a challenge. Orexin-A is a hypothalamic peptide, and its effects in OA are unknown. In this study, we found that exposure to interleukin-1β (IL-1β) reduced the expression of orexin-2R, the receptor of orexin-A in TC-28a2 chondrocytes. Importantly, the senescence-associated β-galactosidase (SA-β-gal) staining assay demonstrated that orexin-A treatment ameliorates IL-1β-induced cellular senescence. Importantly, the presence of IL-1β significantly reduced the telomerase activity of TC-28a2 chondrocytes, which was rescued by orexin-A. We also found that orexin-A prevented IL-1β-induced increase in the levels of Acetyl-p53 and the expression of p21. It is shown that orexin-A mitigates IL-1β-induced reduction of sirtuin 3 (SIRT3). Silencing of SIRT3 abolished the protective effects of orexin-A against IL-1β-induced cellular senescence. These results imply that orexin-A might serve as a promising therapeutic agent for OA.

FNDC5 prevents oxidative stress and neuronal apoptosis after traumatic brain injury through SIRT3-dependent regulation of mitochondrial quality control

Mitochondrial dysfunction and oxidative stress are important mechanisms for secondary injury after traumatic brain injury (TBI), which result in progressive pathophysiological exacerbation. Although the Fibronectin type III domain-containing 5 (FNDC5) was reported to repress oxidative stress by retaining mitochondrial biogenesis and dynamics, its possible role in the secondary injury after TBI remain obscure. In present study, we observed that the level of serum irisin (the cleavage product of FNDC5) significantly correlated with the neurological outcomes of TBI patients. Knockout of FNDC5 increased the lesion volume and exacerbated apoptosis and neurological deficits after TBI in mice, while FNDC5 overexpression yielded a neuroprotective effect. Moreover, FNDC5 deficiency disrupted mitochondrial dynamics and function. Activation of Sirtuin 3 (SIRT3) alleviated FNDC5 deficiency-induced disruption of mitochondrial dynamics and bioenergetics. In neuron-specific SIRT3 knockout mice, FNDC5 failed to attenuate TBI-induced mitochondrial damage and brain injuries. Mechanically, FNDC5 deficiency led to reduced SIRT3 expression via enhanced ubiquitin degradation of transcription factor Nuclear factor erythroid 2-related factor 2 (NRF2), which contributed to the hyperacetylation and inactivation of key regulatory proteins of mitochondrial dynamics and function, including OPA1 and SOD2. Finally, engineered RVG29-conjugated nanoparticles were generated to selectively and efficiently deliver irisin to the brain of mice, which yielded a satisfactory curative effect against TBI. In conclusion, FNDC5/irisin exerts a protective role against acute brain injury by promoting SIRT3-dependent mitochondrial quality control and thus represents a potential target for neuroprotection after TBI.

2-APQC, a small-molecule activator of Sirtuin-3 (SIRT3), alleviates myocardial hypertrophy and fibrosis by regulating mitochondrial homeostasis

Sirtuin 3 (SIRT3) is well known as a conserved nicotinamide adenine dinucleotide+ (NAD+)-dependent deacetylase located in the mitochondria that may regulate oxidative stress, catabolism and ATP production. Accumulating evidence has recently revealed that SIRT3 plays its critical roles in cardiac fibrosis, myocardial fibrosis and even heart failure (HF), through its deacetylation modifications. Accordingly, discovery of SIRT3 activators and elucidating their underlying mechanisms of HF should be urgently needed. Herein, we identified a new small-molecule activator of SIRT3 (named 2-APQC) by the structure-based drug designing strategy. 2-APQC was shown to alleviate isoproterenol (ISO)-induced cardiac hypertrophy and myocardial fibrosis in vitro and in vivo rat models. Importantly, in SIRT3 knockout mice, 2-APQC could not relieve HF, suggesting that 2-APQC is dependent on SIRT3 for its protective role. Mechanically, 2-APQC was found to inhibit the mammalian target of rapamycin (mTOR)-p70 ribosomal protein S6 kinase (p70S6K), c-jun N-terminal kinase (JNK) and transforming growth factor-β (TGF-β)/ small mother against decapentaplegic 3 (Smad3) pathways to improve ISO-induced cardiac hypertrophy and myocardial fibrosis. Based upon RNA-seq analyses, we demonstrated that SIRT3-pyrroline-5-carboxylate reductase 1 (PYCR1) axis was closely assoiated with HF. By activating PYCR1, 2-APQC was shown to enhance mitochondrial proline metabolism, inhibited reactive oxygen species (ROS)-p38 mitogen activated protein kinase (p38MAPK) pathway and thereby protecting against ISO-induced mitochondrialoxidative damage. Moreover, activation of SIRT3 by 2-APQC could facilitate AMP-activated protein kinase (AMPK)-Parkin axis to inhibit ISO-induced necrosis. Together, our results demonstrate that 2-APQC is a targeted SIRT3 activator that alleviates myocardial hypertrophy and fibrosis by regulating mitochondrial homeostasis, which may provide a new clue on exploiting a promising drug candidate for the future HF therapeutics.

Evaluating the Role of Neddylation Modifications in Kidney Renal Clear Cell Carcinoma: An Integrated Approach Using Bioinformatics, MLN4924 Dosing Experiments, and RNA Sequencing

BACKGROUND

Neddylation, a post-translational modification process, plays a crucial role in various human neoplasms. However, its connection with kidney renal clear cell carcinoma (KIRC) remains under-researched.

METHODS

We validated the Gene Set Cancer Analysis Lite (GSCALite) platform against The Cancer Genome Atlas (TCGA) database, analyzing 33 cancer types and their link with 17 neddylation-related genes. This included examining copy number variations (CNVs), single nucleotide variations (SNVs), mRNA expression, cellular pathway involvement, and methylation. Using Gene Set Variation Analysis (GSVA), we categorized these genes into three clusters and examined their impact on KIRC patient prognosis, drug responses, immune infiltration, and oncogenic pathways. Afterward, our objective is to identify genes that exhibit overexpression in KIRC and are associated with an adverse prognosis. After pinpointing the specific target gene, we used the specific inhibitor MLN4924 to inhibit the neddylation pathway to conduct RNA sequencing and related in vitro experiments to verify and study the specificity and potential mechanisms related to the target. This approach is geared towards enhancing our understanding of the prognostic importance of neddylation modification in KIRC.

RESULTS

We identified significant CNV, SNV, and methylation events in neddylation-related genes across various cancers, with notably higher expression levels observed in KIRC. Cluster analysis revealed a potential trade-off in the interactions among neddylation-related genes, where both high and low levels of gene expression are linked to adverse prognoses. This association is particularly pronounced concerning lymph node involvement, T stage classification, and Fustat score. Simultaneously, our research discovered that PSMB10 exhibits overexpression in KIRC when compared to normal tissues, negatively impacting patient prognosis. Through RNA sequencing and in vitro assays, we confirmed that the inhibition of neddylation modification could play a role in the regulation of various signaling pathways, thereby influencing the prognosis of KIRC. Moreover, our results underscore PSMB10 as a viable target for therapeutic intervention in KIRC, opening up novel pathways for the development of targeted treatment strategies.

CONCLUSION

This study underscores the regulatory function and potential mechanism of neddylation modification on the phenotype of KIRC, identifying PSMB10 as a key regulatory target with a significant role in influencing the prognosis of KIRC.

The protective mechanism of SIRT3 and potential therapy in acute kidney injury

Acute kidney injury (AKI) is a complex clinical syndrome with a poor short-term prognosis, which increases the risk of the development of chronic kidney diseases and end-stage kidney disease. However, the underlying mechanism of AKI remains to be fully elucidated, and effective prevention and therapeutic strategies are still lacking. Given the enormous energy requirements for filtration and absorption, the kidneys are rich in mitochondria, which are unsurprisingly involved in the onset or progression of AKI. Accumulating evidence has recently documented that Sirtuin 3 (SIRT3), one of the most prominent deacetylases highly expressed in the mitochondria, exerts a protective effect on AKI. SIRT3 protects against AKI by regulating energy metabolism, inhibiting oxidative stress, suppressing inflammation, ameliorating apoptosis, inhibiting early-stage fibrosis and maintaining mitochondrial homeostasis. Besides, a number of SIRT3 activators have exhibited renoprotective properties both in animal models and in vitro experiments, but have not yet been applied to clinical practice, indicating a promising therapeutic approach. In this review, we unravel and summarize the recent advances in SIRT3 research and the potential therapy of SIRT3 activators in AKI.

Metabolic plasticity of T cell fate decision

ABSTRACT

The efficacy of adaptive immune responses in cancer treatment relies heavily on the state of the T cells. Upon antigen exposure, T cells undergo metabolic reprogramming, leading to the development of functional effectors or memory populations. However, within the tumor microenvironment (TME), metabolic stress impairs CD8 + T cell anti-tumor immunity, resulting in exhausted differentiation. Recent studies suggested that targeting T cell metabolism could offer promising therapeutic opportunities to enhance T cell immunotherapy. In this review, we provide a comprehensive summary of the intrinsic and extrinsic factors necessary for metabolic reprogramming during the development of effector and memory T cells in response to acute and chronic inflammatory conditions. Furthermore, we delved into the different metabolic switches that occur during T cell exhaustion, exploring how prolonged metabolic stress within the TME triggers alterations in cellular metabolism and the epigenetic landscape that contribute to T cell exhaustion, ultimately leading to a persistently exhausted state. Understanding the intricate relationship between T cell metabolism and cancer immunotherapy can lead to the development of novel approaches to improve the efficacy of T cell-based treatments against cancer.