The sirtuin family in health and disease

SIRT1/DNMT3B-mediated epigenetic gene silencing in response to phytoestrogens in mammary epithelial cells

We performed an integrated analysis of genome-wide DNA methylation and expression datasets in normal cells and healthy animals exposed to polyphenols with estrogenic activity (i.e. phytoestrogens). We identified that phytoestrogens target genes linked to disrupted cellular homeostasis, e.g. genes limiting DNA break repair (RNF169) or promoting ribosomal biogenesis (rDNA). Existing evidence suggests that DNA methylation may be governed by sirtuin 1 (SIRT1) deacetylase via interactions with DNA methylating enzymes, specifically DNMT3B. Since SIRT1 was reported to be regulated by phytoestrogens, we test whether phytoestrogens suppress genes related to disrupted homeostasis via SIRT1/DNMT3B-mediated transcriptional silencing. Human MCF10A mammary epithelial cells were treated with phytoestrogens, pterostilbene (PTS) or genistein (GEN), followed by analysis of cell growth, DNA methylation, gene expression, and SIRT1/DNMT3B binding. SIRT1 occupancy at the selected phytoestrogen-target genes, RNF169 and rDNA, was accompanied by consistent promoter hypermethylation and gene downregulation in response to GEN, but not PTS. GEN-mediated hypermethylation and SIRT1 binding were linked to a robust DNMT3B enrichment at RNF169 and rDNA promoters. This was not observed in cells exposed to PTS, suggesting a distinct mechanism of action. Although both SIRT1 and DNMT3B bind to RNF169 and rDNA promoters upon GEN, the two proteins do not co-occupy the regions. Depletion of SIRT1 abolishes GEN-mediated decrease in rDNA expression, suggesting SIRT1-dependent epigenetic suppression of rDNA by GEN. These findings enhance our understanding of the role of SIRT1-DNMT3B interplay in epigenetic mechanisms mediating the impact of phytoestrogens on cell biology and cellular homeostasis.

Gut microbiota-derived 4-hydroxyphenylacetic acid from resveratrol supplementation prevents obesity through SIRT1 signaling activation

Resveratrol (RSV), a natural polyphenol, has been suggested to influence glucose and lipid metabolism. However, the underlying molecular mechanism of its action remains largely unknown due to its multiple biological targets and low bioavailability. In this study, we demonstrate that RSV supplementation ameliorates high-fat-diet (HFD)-induced gut microbiota dysbiosis, enhancing the abundance of anti-obesity bacterial strains such as Akkermansia, Bacteroides and Blautia. The critical role of gut microbiota in RSV-mediated anti-obesity effects was confirmed through antibiotic-induced microbiome depletion and fecal microbiota transplantation (FMT), which showed that RSV treatment effectively mitigates body weight, histopathological damage, glucose dysregulation and systematic inflammation associated with HFD. Metabolomics analysis revealed that RSV supplementation significantly increases the levels of the gut microbial flavonoid catabolite 4-hydroxyphenylacetic acid (4-HPA). Notably, 4-HPA was sufficient to reverse obesity and glucose intolerance in HFD-fed mice. Mechanistically,4-HPA treatment markedly regulates SIRT1 signaling pathways and induces the expression of beige fat and thermogenesis-specific markers in white adipose tissue (WAT). These beneficial effects of 4-HPA are partially abolished by EX527, a known SIRT1 inhibitor. Collectively, our findings indicate that RSV improve obesity through a gut microbiota-derived 4-HPA-SIRT1 axis, highlighting gut microbiota metabolites as a promising target for obesity prevention.

Overexpressed Rv0222 in M. smegmatis suppresses host innate immunity by downregulating miR-9 target SIRT1

Tuberculosis (TB) remains one of the most fatal infectious diseases, the pathogenic bacterium Mycobacterium tuberculosis (Mtb) has a thick wall to resist the invasion of extracellular substances and secretes a variety of virulence proteins to antagonize host innate immunity. Rv0222, a protein encoded by the gene Rv0222 in the RD4 region of Mtb, is a critical virulence factor in the pathogenicity of Mtb. However, the mechanism of its regulation of miRNAs during bacterial infection is unclear. We used Rv0222 gene and Mycobacterium smegmatis (M. smegmatis), which is highly homologous to Mtb, to construct Rv0222 recombinant M. smegmatis Ms_Rv0222. Ms_Rv0222 induced down-regulation of miR-9 expression and up-regulation of SIRT1 in RAW264.7 cells and mice post-infection. Up-regulation of SIRT1 caused down-regulation of p65 activity and decreased the expression of pro-inflammatory cytokine, which increased the intracellular survival of M. smegmatis. Si-SIRT1 induced up-regulation of p65 activity and increased the expression of pro-inflammatory cytokine, then decreased the intracellular survival of M. smegmatis. This study reveals that Mtb Rv0222 mediates the suppression of host innate immunity by miR-9 and its target SIRT1, and may provide a potential site for the development of new anti-TB drugs targeting Rv0222.

SIRT2 alleviates pre-eclampsia via prompting mitochondrial biogenesis and function

AIMS

Pre-eclampsia (PE) globally impacts 2-8 % of pregnancies and is a leading cause of neonatal and maternal morbidity and mortality. Recent studies found the association between mitochondrial dysfunction and deficient motility of trophoblast cells in PE. Lower expressions of mitochondrial biogenesis related proteins (i.e. PGC1α, NRF1 and TFAM) and SIRT2 have recently been found. However, the regulative role of SIRT2 on the protein expression and acetylation of PGC1α and its influence on trophoblast migration and invasion in PE have never been investigated.

MATERIALS AND METHODS

The alterations in protein expressions of SIRT2 and PGC1α/NRF1/TFAM were examined in the placenta from pregnant women with and without PE. The role of SIRT2 on mitochondrial biogenesis and mitochondrial morphology/function was explored in trophoblast cell, and the findings were confirmed in the LPS-induced PE mice with adeno-associated virus transfection system.

KEY FINDINGS

We demonstrated the lower protein expressions of SIRT2 and PGC1α/NRF1/TFAM and mitochondrial dysfunction in PE patients and mice compared with counterparts. Moreover, overexpression of SIRT2 enhanced the protein expressions of PGC1α and deacetylated PGC1α, and further facilitating mitochondrial function and motility of trophoblast cells. In vivo, overexpression of SIRT2 attenuated the PE-like symptoms and adverse pregnancy outcomes in LPS-induced PE mice via promoting mitochondrial biogenesis.

SIGNIFICANCE

Above findings suggest that SIRT2 might be a potential interventive target against PE via improving deacetylation of PGC1α and mitochondrial biogenesis and function.

Beta-catenin/sirtuin 1/farnesoid X receptor pathway promotion of portal vein ligation and parenchymal transection-induced rapid liver regeneration

BACKGROUND

By accelerating the regeneration of the future liver remnant, portal vein ligation and parenchymal transection allows for more extensive hepatectomy. Given that the mechanism remains poorly understood, the aim of this study was to investigate the mechanism of portal vein ligation and parenchymal transection-induced liver regeneration.

METHODS

A portal vein ligation and parenchymal transection-induced liver regeneration mouse model was established, followed by RNA microarray analysis to identify candidate molecules. Genomic deletion and chemical manipulation of target molecules were used to explore their functions in portal vein ligation and parenchymal transection-induced liver regeneration. Validation was conducted using a diseased liver model and human samples.

RESULTS

Portal vein ligation and parenchymal transection-induced liver regeneration was significantly accelerated compared with that in sham-operated mice (P < .05). An RNA microarray revealed that Sirtuin 1 is a crucial molecule in the proliferation of the future liver remnant. Regardless of whether Sirtuin 1 is inhibited chemically or through genetic deletion, portal vein ligation and parenchymal transection-induced liver regeneration is distinctly attenuated. Further investigation revealed that Sirtuin 1 promoted portal vein ligation and parenchymal transection-induced liver regeneration via the farnesoid X receptor. In addition, beta-catenin also was found to participate in the process of future liver remnant proliferation. Chemical inhibition of beta-catenin markedly impaired but activation of WNT/beta-catenin mildly enhanced portal vein ligation and parenchymal transection-induced liver regeneration (P < .05). Deletion of Sirtuin 1 blocked the facilitating effect of beta-catenin on portal vein ligation and parenchymal transection-induced liver regeneration. These findings were validated in diseased liver models and patient samples, confirming the correlation between the beta-catenin/Sirtuin 1/farnesoid X receptor pathway and portal vein ligation and parenchymal transection-induced liver regeneration.

CONCLUSION

Activation of the beta-catenin/Sirtuin 1/farnesoid X receptor pathway offers critical mechanistic insights into accelerating portal vein ligation and parenchymal transection-induced liver regeneration. Modulation of beta-catenin/Sirtuin 1/farnesoid X receptor may therefore improve clinical outcomes in patients receiving staged hepatectomy.

Sirt4 Overexpression Modulates the JAK2/STAT3 and PI3K/AKT/mTOR Axes to Alleviate Sepsis-Induced Acute Lung Injury

BACKGROUND

Sepsis-induced acute lung injury (ALI) is a severe organ dysfunction characterized by lung inflammation and apoptosis. The mechanisms underlying sepsis-induced ALI remain poorly understood. Here, we determined the effects of sirtuin 4 (SIRT4) on sepsis-induced ALI.

METHODS

Lipopolysaccharide (LPS)-induced injury cell and cecal ligation and puncture (CLP) animal models were established. Overexpression vectors and lentiviral transfections were used to upregulate SIRT4 expression. Lung cell apoptosis, inflammation, and the levels of associated factors were evaluated. Changes in the PI3K/AKT/mTOR and JAK2/STAT3 pathways were measured, and their potential involvement was examined using LY294002 (PI3K inhibitor), 740 Y-P (PI3K agonist), AG490 (JAK2 inhibitor), and coumermycin A1 (JAK2 agonist).

RESULTS

Lower SIRT4 expression was observed in LPS-exposed A549 cells and CLP rats. In LPS-induced A549 cells, Sirt4 overexpression enhanced cell viability, resisted apoptosis, restored the expression of apoptosis-associated proteins (HMB1, cleaved CASP3, BAX, and BCL), and reduced the secretion of pro-inflammatory cytokines (IL-6, IL-1β, and TNF-α). In CLP rats, Sirt4 overexpression prolonged survival time, alleviated lung histopathological damage, reduced pulmonary edema, mitigated lung infection, decreased lung apoptosis, and lowered serum levels of inflammatory cytokines. Furthermore, Sirt4 overexpression blocked JAK2/STAT3/AKT/mTOR phosphorylation. 740 Y-P and coumermycin A1 reversed the protective effects of Sirt4 overexpression in LPS-treated A549 cells, resulting in decreased cell viability and increased apoptosis. LY294002 and AG490 enhanced the protective effects of Sirt4 overexpression in LPS-treated A549 cells.

CONCLUSION

SIRT4 alleviates sepsis-induced ALI by inhibiting JAK2/STAT3/PI3K/AKT/mTOR signaling. Upregulating SIRT4 expression may serve as an innovative therapeutic approach for lung injury management in sepsis.

Genome-wide identification and expression analysis of the SIRT gene family in Nile tilapia (Oreochromis niloticus)

The sirtuin (SIRT) family is a nicotine adenine dinucleotide (NAD+)-dependent class III histone deacetylase, which is widely involved in numerous physiological processes of organisms, such as metabolism, reproduction, and immunity. Here, based on the genomics database, comprehensive analysis of the SIRT gene in Nile tilapia (Oreochromis niloticus) was analyzed using bioinformatics methods and quantitative real-time PCR. The nine SIRT genes of O. niloticus (OnSIRT) were distributed on eight chromosomes. The OnSIRTs contain distinct sequences from 3 exons in OnSIRT4 to 16 exons in OnSIRT2, however, they share conserved domains and protein motifs. Phylogenetic analysis shows that the OnSIRTs belong to four subfamilies and are highly conserved in teleosts, and evolution is characterized primarily by purification selection. The OnSIRT genes showed diversified expression patterns in fourteen tissues of O. niloticus. OnSIRT2, OnSIRT3, OnSIRT3.2, OnSIRT6, and OnSIRT7 are mainly expressed in the gonads, especially in the ovary. OnSIRT1 and OnSIRT4 are mainly expressed in the kidney. OnSIRT5a is mainly expressed in the stomach, however, OnSIRT5b is mainly expressed in the liver and spleen. The results of this study provide a basis information for further exploration of the function and molecular mechanism of the SIRT gene family in teleosts.

The impact of fasting and caloric restriction on rheumatoid arthritis in humans: A narrative review

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease affecting approximately 1 % of the global population. It is characterized by swollen and painful joints eventually evolving into bone erosion, cartilage degradation and systemic inflammation, that significantly reduce patients' quality of life. While modern pharmacological treatments often lead to symptom improvement, they are also accompanied by substantial side effects, which can further impair patient wellbeing. Dietary interventions, particularly fasting and caloric restriction (CR), have gained increasing attention as adjunctive strategies for RA prevention and treatment. Their anti-inflammatory potential and ability to modulate the gut microbiome render them an attractive option to accompany or modify medical treatment. However, high-quality research on fasting and CR interventions in humans with RA remains limited, and the underlying mechanisms are not yet fully understood. The present narrative review reflects our current knowledge regarding fasting and CR, emphasising their impact on clinical outcomes, potential underlying mechanism and the sustainability of their effects. Evidence suggests that fasting and CR may lead to short-term improvements in RA disease activity, including reductions in inflammatory markers such as C-reactive protein (CRP) and interleukin-6 (IL-6). However, their long-term efficacy remains uncertain due to the limited duration of most studies. Future research should focus on identifying optimal fasting and CR protocols and their feasibility in long-term disease management, along with investigating patient adherence and potential risks associated with fasting interventions.

Geroprotective applications of oleuropein and hydroxytyrosol through the hallmarks of ageing

Geroprotectors are compounds that target the underlying mechanisms of ageing to delay the onset of age-related diseases and extend both lifespan and health span. As ageing is driven by the accumulation of cellular damage, DNA instability, epigenetic changes, mitochondrial dysfunction, and chronic inflammation, the concept of geroprotection focuses on compounds that can mitigate these processes. Oleuropein (OLE) and its derivative hydroxytyrosol (HT), both phenolic molecules derived from Olea europaea (olive tree), have gained significant attention as potential geroprotectors due to their potent antioxidant and anti-inflammatory properties. These phytochemicals, central to the Mediterranean diet, activate key molecular pathways such as nuclear factor erythroid 2-related factor 2, reducing oxidative stress and modulating inflammatory responses. Through these mechanisms, OLE and HT help counteract inflammageing, a critical factor in age-related dysfunction. This review highlights the role of OLE and HT as geroprotective agents, emphasising their ability to target the hallmarks of ageing and their potential to improve health span by slowing the progression of age-related conditions. With proven efficacy in various biological models, these compounds represent promising tools in the ongoing search for strategies to enhance the quality of life in ageing populations.

Meta-epigenetic shifts in T cell aging and aging-related dysfunction

Epigenetic regulation, including DNA methylation and histone modifications, play a pivotal role in shaping T cell functionality throughout life. With aging, these epigenetic changes profoundly affect gene expression, altering T cell plasticity, activation, and differentiation. These modifications contribute significantly to immunosenescence, increasing susceptibility to infections, cancer, and autoimmune diseases. In CD8⁺ T cells, chromatin closure at key regulatory regions suppresses activation and migration, while chromatin opening in pro-inflammatory gene loci amplifies inflammation. These changes drive terminal differentiation, characterized by increased expression of senescence-associated markers, impaired migration and loss of epigenetic plasticity. CD4⁺ T cells experience fewer but critical epigenetic alterations, including disrupted pathways, a skewed Th1/Th2 balance, and reduced Treg functionality. These epigenetic changes, compounded by metabolic dysfunctions, such as mitochondrial deficiency and oxidative stress, impair T-cell adaptability and resilience in the aging organism. Therefore, understanding the interplay between epigenetic and metabolic factors in T cell aging offers promising therapeutic opportunities to mitigate immunosenescence and enhance immune function in aging populations. This review explores the interplay between DNA methylation, histone alterations, and metabolic changes underlying T cell aging.

Epigenetic Modifications in Sensorineural Hearing Loss: Protective Mechanisms and Therapeutic Potential

Hearing loss, which currently affects more than 430 million individuals globally and is projected to exceed 700 million by 2050, predominantly manifests as sensorineural hearing loss (SNHL), for which existing technologies such as hearing aids and cochlear implants fail to restore natural auditory function. Research focusing on protecting inner ear hair cells (HCs) from harmful factors through the regulation of epigenetic modifications has gained significant attention in otology for its role in regulating gene expression without altering the DNA sequence, suggesting potential strategies for preventing and treating SNHL. By synthesizing relevant studies on the inner ear, this review summarizes the emerging roles of histone modifications, DNA methylation, and noncoding RNAs in HC damage, with a focus on their therapeutic potential through epigenetic modulation. Moreover, this review examines the therapeutic potential of epigenetic regulation for the prevention and treatment of SNHL, emphasizing the application of small-molecule epigenetic compounds and their efficacy in modulating gene expression to preserve and restore auditory function.

Microbiota-derived indole acetic acid extends lifespan through the AhR-Sirt2 pathway in Drosophila

Disruption of aryl hydrocarbon receptor (AhR) signaling and aberrant tryptophan metabolism have been shown to be highly associated with aging and age-related disorders. However, the underlying molecular mechanisms by which the AhR-mediated signaling pathway contributes to the aging process remain largely unknown. In this study, we find that aged Drosophila exhibits markedly reduced tryptophan metabolism leading to impaired AhR ligands, especially indole acetic acid (IAA), compared with their young controls. Supplementation with IAA, produced from Lactobacillus spp., dose-dependently extends the lifespan of Drosophila and improves healthy aging with resistance to starvation and oxidative stress. Mechanistically, activation of AhR by IAA markedly enhances Sirt2 activity by binding to its promoter, thereby inhibiting downstream TOR signaling and related fatty acid and amino acid metabolism. Both Ahr and Sirt2 mutant flies with IAA supplementation display a negligible lifespan extension, suggesting that AhR-mediated Sirt2 signaling contributes to lifespan extension in flies upon IAA supplementation. From the perspective of host metabolism, IAA supplementation significantly increases unsaturated fatty acids (UFAs) in aged flies, which are regarded to be beneficial for healthy status. These findings provide new insights into the physiological functions of AhR involved in the aging process by mediating Sirt2 signaling.

IMPORTANCE

Disruption of aryl hydrocarbon receptor (AhR) signaling and aberrant tryptophan metabolism contribute to aging and age-related disorders, but the underlying molecular mechanisms are largely unknown. Using multiomics analyses combined with biochemical assays, this study reveals that AhR activation by indole acetic acid (IAA) effectively extends the lifespan accompanied by improved healthy aging in Drosophila via the AhR-Sirt2 pathway.

Microcystin-LR Induces Lipid Metabolism Disorder in Pelophylax nigromaculatus Tadpoles via the Gut-Liver Axis

Disruption of lipid homeostasis in aquatic animals poses serious health risks, including tissue damage and systemic metabolic dysfunction. The precise mechanisms by which microcystin-LR, a potent cyanotoxin, disrupts lipid metabolism in amphibian tadpoles remain unclear. In this study, tadpoles (Pelophylax nigromaculatus) were exposed to MC-LR and fecal microbiota transplantation (FMT) experiments were performed to investigate whether or how MC-LR at environmental concentrations interfered with tadpole lipid metabolism from the perspective of the gut microbiota-gut-liver axis. Following exposure, the liver exhibited significant inflammation, hypertrophy, and fibrosis, accompanied by elevated serum lipid levels. Furthermore, the expression levels of the farnesoid X receptor (FXR), a nuclear receptor, were significantly downregulated. Molecular docking and molecular dynamics simulations indicated a strong and stable binding between FXR and MC-LR. Moreover, MC-LR suppressed liver FXR expression or activity, triggering: (1) upregulation of sterol regulatory element-binding protein 1 (SREBP1)-mediated triglyceride (TG) synthesis, (2) inhibition of free fatty acid (FFA) β-oxidation, and (3) activation of SREBP2-dependent bile acid biosynthesis. Moreover, MC-LR altered the composition of gut microbiota and specific bile acid levels (e.g., taurocholic acid and glycochenodeoxycholic acid) in the gut, thereby interfering with hepatic lipid metabolism, as evidenced by FMT-induced hepatic lipid accumulation in recipient tadpoles. These findings identify FXR as a potentially key molecular target for MC-LR and suggest that changes in bile acid levels of intestinal microbiota metabolism also may be an important pathway driving hepatic lipid dysregulation in amphibians exposed to environmental concentrations of MC-LR.

Apoptotic Bodies Restore NAD and Mitochondrial Homeostasis in Fibroblasts

Fibrotic skin diseases are characterized by excessive fibroblast proliferation and pathological extracellular matrix deposition. As a pivotal coenzyme in cellular energetics, NAD homeostasis perturbation is implicated in fibrosis. Multiple studies have demonstrated the therapeutic potential of mesenchymal stem cells (MSCs) against cutaneous fibrosis, while the specific mechanism remains elusive. Herein, this work finds that although almost all MSCs undergo in situ apoptosis within 24 h post-subcutaneous administration, MSC-derived apoptotic bodies (ABs) mediated potent anti-fibrotic effects. Mechanistically, ABs can restore NAD and mitochondrial homeostasis through NAMPT transfer, FOXO1 deacetylation enhancement, and PINK1/PARKIN-dependent mitophagy activation. To achieve penetration into the hard matrix of fibrotic skin, permeable apoptotic bodies (pABs) are constructed via metabolic glycoengineering and copper-free click chemistry techniques. In both keloid xenograft and scleroderma murine models, pABs can significantly penetrate collagen matrix and reduce skin fibrosis. In summary, this research establishes a highly promising strategy for reversing skin fibrosis with hard fibrotic matrix.

Aging and Lifestyle Modifications for Preventing Aging-Related Diseases

The pathogenesis of various chronic diseases is closely associated with aging. Aging of the cardiovascular system promotes the development of severe cardiovascular diseases with high mortality, including atherosclerosis, coronary heart disease, and myocardial infarction. Similarly, aging of the nervous system promotes the development of neurodegenerative diseases, such as Alzheimer's disease, which seriously impairs cognitive function. Aging of the musculoskeletal system is characterized by decreased function and mobility. The molecular basis of organ aging is cellular senescence, which involves multiple cellular and molecular mechanisms, such as impaired autophagy, metabolic imbalance, oxidative stress, and persistent inflammation. Given the ongoing demographic shift toward an aging society, strategies to delay or reduce the effects of aging have gained significance. Lifestyle modifications, such as exercise and calorie restriction, are now recognized for their anti-aging effects, their capacity to reduce modification, their potential to prolong lifespan, and their capacity to lower the risk of cardiovascular disease. This review elucidates the molecular mechanisms and application significance of various anti-aging approaches at the molecular level, based on research progress in aging. It aims to provide a reference for the prevention and treatment of age-related diseases in progressively aging societies.

Therapeutic applications of exercise in neurodegenerative diseases: focusing on the mechanism of SIRT1

Neurodegenerative diseases comprise a group of central nervous system disorders marked by progressive neuronal degeneration and dysfunction. Their pathogenesis is multifactorial, involving oxidative stress, mitochondrial dysfunction, excitotoxicity, and neuroinflammation. Recent research has highlighted the potential of exercise as a non-pharmacological intervention for both the prevention and treatment of these disorders. In particular, exercise has received growing attention for its capacity to upregulate the expression and activity of SIRT1, a critical mediator of neuroprotection via downstream signaling pathways. SIRT1, a key member of the Sirtuin family, is a nicotinamide adenine dinucleotide (NAD +)-dependent class III histone deacetylase. It plays an essential role in regulating cellular metabolism, energy homeostasis, gene expression, and cellular longevity. In the context of neurodegenerative diseases, SIRT1 confers neuroprotection by modulating multiple signaling cascades through deacetylation, suppressing neuronal apoptosis, and promoting neural repair and regeneration. Exercise enhances SIRT1 expression and activity by increasing NAD + synthesis and utilization, improving intracellular redox balance, alleviating oxidative stress-induced inhibition of SIRT1, and thereby promoting its activation. Moreover, exercise may indirectly modulate SIRT1 function by influencing interacting molecular networks. This review summarizes recent advances in the therapeutic application of exercise for neurodegenerative diseases, with a focus on SIRT1 as a central mechanism. It examines how exercise mediates neuroprotection through the regulation of SIRT1 and its associated molecular mechanisms and signaling pathways. Finally, the paper discusses the potential applications and challenges of integrating exercise and SIRT1-targeted strategies in the management of neurodegenerative diseases, offering novel perspectives for the development of innovative treatments and improvements in patients' quality of life.

Modulation of Sirtuins to address aging related disorders through the use of selected phytochemicals

BACKGROUND

Aging is a complex phenomenon involving oxidative stress, inflammation, and cellular damage subsequently leading to various disorders, such as cardiovascular diseases, neurodegenerative disorders, diabetes, and cancer. Sirtuin (SIRT) proteins are one of the major molecular factors that affect human aging. Sirtuins are a class of NAD+-dependent enzymes that control oxidative stress response, DNA damage repair, inflammation and metabolism, all of which are involved in aging and age-related diseases.

PURPOSE

The objective of this review is to elucidate the potential role of SIRT in the aging process and modulation of SIRT pathway through selected phytochemicals like Curcumin, Resveratrol, Quercetin, and Kaempferol.

RESULTS

Studies convincedly revealed that SIRT pathway represents a promising avenue for extending the human health span and addressing age-related conditions. Phytochemicals like Curcumin, Resveratrol, Quercetin, and Kaempferol have shown excellent potential to mediate aging effects through their potent antioxidant, anti-inflammatory, and regulatory activities. These potent bioactive compounds enhance oxidative stress response, genomic integrity, neuroprotective and anti-inflammatory activities through SIRT pathway modulation. Furthermore, in addition to antiaging effects, other therapeutic benefits are also associated with each compound including nervous disorders, cancer, and metabolic disorders are also briefly highlighted. Studies reported convincing evidence that Curcumin, Resveratrol, Quercetin, and Kaempferol, effectively modulate SIRT expression/activity leading to improved cell stress tolerance, reduced oxidation and enhanced metabolic state.

CONCLUSIONS

Collectively, studies revealed the comprehensive nutraceutical significance of Curcumin, Resveratrol, Quercetin, and Kaempferol as anti-aging therapeutics and warrant future studies to exploit the full potential of these natural compounds.

Natural Bioproducts with Epigenetic Properties for Treating Cardiovascular Disorders

Cardiovascular disorders (CVDs) are the leading cause of mortality worldwide, highlighting an urgent need for innovative therapeutic strategies. Recent advancements highlight the potential of naturally derived bioproducts with epigenetic properties to offer protection against CVDs. These compounds act on key epigenetic mechanisms, DNA methylation, histone modifications, and non-coding RNA regulation to modulate gene expression essential for cardiovascular health. This review explores the effects of various bioproducts, such as polyphenols, flavonoids, and other natural extracts, on these epigenetic modifications and their potential benefits in preventing and managing CVDs. We discuss recent discoveries and clinical applications, providing insights into the epigenetic regulatory mechanisms of these compounds as potential epidrugs, naturally derived agents with promising therapeutic prospects in epigenetic therapy for CVDs.

Fn14 Controls the SIRT2-Mediated Deacetylation of Slug to Inhibit the Metastasis of Epithelial Ovarian Cancer

Metastatic spread of cancer is the leading cause of death in patients with epithelial ovarian cancer (EOC), and elucidation of the molecular mechanisms underlying this process is a major focus of cancer research. Fibroblast growth factor-inducible 14 (Fn14) has been shown to regulate wound repair, inflammation, angiogenesis, and chemoresistance, but its functional role in metastasis in EOC is still unknown. Here it is reported that Fn14 is identified as a cancer metastasis suppressor that inhibits the migratory and invasive potential of EOC cells by down-regulating epithelial-mesenchymal transition (EMT). Mechanistically, it is identified that Fn14 promotes acetylation-dependent protein degradation of Slug, a key transcriptional factor associated with EMT. The deacetylase Sirtuin 2 (SIRT2) has been reported to be involved in the deacetylation of Slug protein to stabilize it and then prevent its degradation in the nucleus. The results showed that Fn14 alters the subcellular localization of (SIRT2) by interacting with SIRT2, leading to reduced SIRT2 shuttling into the nucleus and subsequently promoting the acetylated degradation of Slug. Collectively, the work has demonstrated for the first time that Fn14 inhibits EOC metastasis by regulating SIRT2-mediated Slug deacetylation, providing a new perspective and method for the development of future novel therapeutic strategies for the treatment of EOC metastasis.

Identification of SIRT3 modulating compounds in deep-sea fungi metabolites: Insights from molecular docking and MD simulations

SIRT3, a crucial deacetylase that plays a key role in regulating mitochondrial acetylation, is tightly linked to metabolic processes and is essential for the maintenance of eukaryotic life. SIRT3 is a potential therapeutic target due to its key role in various diseases, including ageing, heart disease, cancer, and metabolic disorders. In this work, we aimed to identify potential SIRT3 inhibitors from the deep-sea fungal metabolites by employing molecular docking and ADMET analysis. Based on the binding affinities, ten compounds were selected whose docking scores were in the range of -9.693 to -8.327 kcal/mol. Further, four compounds Penipanoid C, Penicillactam, Quinolonimide, and Brevianamide R were selected based on the ADMET properties and subjected to Molecular dynamics simulations to assess the stability of these molecules with target. The stability analysis indicated that the selected compounds could act as lead compounds during in vitro assays to advance these drug candidates towards clinical drug development.

High Concentrations of Circulating 2PY and 4PY-Potential Risk Factor of Cardiovascular Disease in Patients with Chronic Kidney Disease

Recently published data indicate that elevated circulating concentrations of N1-methyl-2-pyridone-5-carboxamide (2PY, also described as Met2PY) and N1-methyl-4-pyridone-5-carboxamide (4PY, also described as Met4PY), terminal catabolites of nicotinamide adenine dinucleotide (NAD+), are associated with cardiovascular disease (CVD) risk in humans. Previously, we and the others have shown that patients with advanced stages of chronic kidney disease (CKD) exhibit several-fold higher circulating 2PY and 4PY concentrations compared to healthy subjects or patients in the early stages of the disease. It is also well documented that patients with advanced CKD stages exhibit markedly elevated CVD risk, which is the main cause of premature death (in these patients). Therefore, we hypothesize that high concentrations of circulating 2PY and 4PY are important factors that may contribute to cardiovascular events and, ultimately, premature death in CKD patients. However, further, accurately controlled clinical research is needed to provide definitive answers concerning the role of 2PY and 4PY in CVD risk in CKD patients. Moreover, we are dealing with some issues related to the use of NAD+ precursors (NAD+ boosters) as drugs (also in CKD patients) and/or supplements. Due to the increase in circulating 2PY and 4PY levels during treatment with NAD+ boosters, these precursors should be used with caution, especially in patients with increased CVD risk.

Role of SIRT3 in the regulation of Gadd45α expression and DNA repair in β-cells

In previous studies, we have shown that growth arrest and DNA damage (Gadd) 45α is required for the repair of nitric oxide-mediated DNA damage in β-cells. Gadd45α expression is stimulated by nitric oxide and requires forkhead box protein (Fox) O1 and NAD+-dependent deacetylase activity. Based on inhibitor studies, we attributed this activity to Sirtuin (SIRT)1; however, the inhibitors used in this previous study also attenuate the deacetylase activity of SIRT2, 3, and 6. We now provide experimental evidence that SIRT1 is dispensable for β-cell expression of Gadd45α and that the mitochondrial localized isoform SIRT3, is required for DNA repair in β-cells. We show that siRNA knockdown of Sirt3 attenuates nitric oxide-stimulated Gadd45α mRNA accumulation in both wildtype and Sirt1-/- INS 832/13 cells as well as isolated rat islets and that SIRT3 inhibition increases FoxO1 acetylation and attenuates DNA repair in response to nitric oxide. While SIRT3 is predominantly localized to mitochondria, a small fraction is localized in the nucleus of insulin-containing cells and functions to participate in the regulation of FoxO1-dependent, nitric oxide-stimulated DNA repair.

The Role of NAD+ Metabolism in Cardiovascular Diseases: Mechanisms and Prospects

Nicotinamide adenine dinucleotide (NAD+) is a promising anti-aging molecule that plays a role in cellular energy metabolism and maintains redox homeostasis. Additionally, NAD+ is involved in regulating deacetylases, DNA repair enzymes, inflammation, and epigenetics, making it indispensable in maintaining the basic functions of cells. Research on NAD+ has become a hotspot, particularly regarding its potential in cardiovascular disease (CVD). Many studies have demonstrated that NAD+ plays a crucial role in the occurrence and development of CVD. This review summarizes the biosynthesis and consumption of NAD+, along with its precursors and their effects on raising NAD+ levels. We also discuss new mechanisms of NAD+ regulation in cardiovascular risk factors and its effects of NAD+ on atherosclerosis, aortic aneurysm, heart failure, hypertension, myocardial ischemia-reperfusion injury, diabetic cardiomyopathy, and dilated cardiomyopathy, elucidating different mechanisms and potential treatments. NAD+-centered therapy holds promising advantages and prospects in the field of CVD.

Role of sirtuins in cerebral ischemia-reperfusion injury: Mechanisms and therapeutic potential

The high incidence and mortality rate of cardiac arrest (CA) establishes it as a critical clinical challenge in emergency medicine globally. Despite continuous advances in advanced life support (ALS) technology, the prognosis for patients experiencing cardiac arrest remains poor, with cerebral ischemia and reperfusion injury (CIRI) being a significant determinant of adverse neurological outcomes and increased mortality. Sirtuins (SIRTs) are a class of highly evolutionarily conserved NAD+-dependent histone deacylenzymes capable of regulating the expression of various cytoprotective genes to play a neuroprotective role in CIRI. SIRTs mainly regulate the levels of downstream proteins such as PGC 1-α, Nrf 2, NLRP 3, FoxOs, and PINK 1 to inhibit inflammatory response, attenuate oxidative stress, improve mitochondrial dysfunction, promote angiogenesis, and inhibit apoptosis while reducing CIRI. Natural active ingredients are widely used in regulating the protein level of SIRTs in the body because of their multi-components, multi-pathway, multi-target, and minimal toxic side effects. However, these naturally active ingredients still face many challenges related to drug targeting, pharmacokinetic properties, and drug delivery. The emergence and vigorous development of new drug delivery systems, such as nanoparticles, micromilk, and exosomes, provide strong support for solving the above problems. In the context of the rapid development of molecular biology technology, non-coding RNA (NcRNA), represented by miRNA and LncRNA, offers great potential for achieving gene-level precision medicine. In the context of multidisciplinary integration, combining SIRTs proteins with biotechnology, omics technologies, artificial intelligence, and material science will strongly promote the deepening of their basic research and expand their clinical application. This review describes the major signaling pathways of targeting SIRTs to mitigate CIRI, as well as the current research status of Chinese and Western medicine and medical means for the intervention level of SIRTs. Meanwhile, the challenges and possible solutions in the clinical application of targeted drugs are summarized. In the context of medical and industrial crossover, the development direction of SIRTs in the future is discussed to provide valuable reference for basic medical researchers and clinicians to improve the clinical diagnosis and treatment effects of CIRI.

SIRT3 regulates PFKFB3-mediated glycolysis to attenuate cisplatin-induced ototoxicity both in vivo and in vitro

Cochlear hair cell death is the primary cause of cisplatin-induced ototoxicity, currently lacking widely applicable clinical methods for effective prevention and treatment. In this study, an in vivo cisplatin-induced ototoxicity model was established by intraperitoneal injection of 12 mg/kg cisplatin. We found that ablation of SIRT3 exacerbates cisplatin-induced hearing loss and cochlear hair cell damage. An in vitro cisplatin-induced ototoxicity model was established using 5 µM cisplatin in cochlear explants and OC-1 cells. We found that the absence of SIRT3 impairs cochlear hair cell glycolytic metabolism, leading to excessive accumulation of ROS and significant reduction in MMP levels, thereby promoting apoptosis. In contrast, overexpression of SIRT3 in OC-1 cells promotes cochlear hair cell survival and reduces cochlear hair cell apoptosis. Inhibition of PFKFB3 reduces glycolytic metabolism in OC-1 cells, and the protective effect conferred by SIRT3 overexpression is lost. In summary, the protective effect of SIRT3 may be mediated by the regulation of PFKFB3-dependent glycolysis and the mitigation of cisplatin-induced excessive ROS accumulation.

SIRT3 mitigates dry eye disease through the activation of autophagy by deacetylation of FOXO1

Dry eye disease (DED) is a complex ocular condition characterized by oxidative stress, inflammation, and apoptosis. An increasing number of studies suggest that Sirtuin3 (SIRT3), a mitochondrial deacetylase, may offer protection against related pathologies. Despite these indications, the precise function and underlying mechanisms of SIRT3 in the context of DED have not been fully elucidated. Here, we observed a decline in SIRT3 expression in human corneal epithelial cells (HCE-Ts) and the corneal conjunctiva of mice as the disease advanced. Overexpression of SIRT3 in HCE-Ts reduced the accumulation of reactive oxygen species (ROS), inflammatory cytokines, and the rate of apoptosis, while its inhibition had the opposite effect. Importantly, the function of SIRT3 was exerted through the enhancement of autophagic flux. Further studies have shown that chloroquine-induced inhibition of autophagy neutralized the beneficial effects of SIRT3. In our in vivo experiments, the application of eye drops containing a SIRT3 agonist ameliorated the symptoms of DED and increased corneal autophagy in mice. Mechanistically, our study identified that the deacetylation and nuclear translocation of FOXO1 (Forkhead box O1) are pivotal for the SIRT3-mediated enhancement of autophagic flux. These findings posit that SIRT3 as an encouraging therapeutic target for DED, offering new insights into the disease's underlying mechanisms.

Elevated cortisol concentration in preterm sheep fetuses impacts heart development

The prepartum rise in cortisol promotes cardiac development and maturation. Here, we investigated the impact of elevated circulating cortisol during mid-late gestation on cardiac growth and metabolism in fetal sheep. Saline or cortisol (2-3 mg in 4.4 mL/24 h) was infused into the fetal jugular vein from 109 to 116 days gestation (dG, term = 150 dG), and fetal heart tissue was collected at 116 dG. Glucocorticoid concentrations, gene and protein expression were measured in fetal left ventricle (LV) tissue. Intrafetal cortisol infusion increased cardiac cortisol concentration but downregulated the protein abundance of glucocorticoid receptor (GR) isoforms (GRα-A, GR-P, GR-A, GRα-D2 and GRα-D3). The gene and protein expression of markers of cardiac hyperplastic growth (IGF1, IGF-1R, TGFβ and AGT) were downregulated, while a protein marker of DNA replication (proliferating cell nuclear antigen) was upregulated by cortisol infusion. Cardiac protein and/or gene expression of complex I of the electron transport chain, SOD2, GLUT-4 (gene and protein), and phosphorylated IRS-1, were upregulated in response to elevated fetal cortisol concentration. Intrafetal cortisol infusion downregulated gene expression of PDK4, which mediates the metabolic switch from glucose to fatty acid metabolism. Cardiac expression of molecular markers involved in cardiovascular protection (SIRT-1, HO1, LAMP1 and SK1) were also downregulated in the cortisol group. In conclusion, these findings suggest that chronic cortisol exposure in preterm fetuses alters heart development, promoting cardiac maturation and potentially increasing the risk of cardiovascular disease later in life if these changes persist into adulthood.

Potential therapeutic targets for ischemic stroke in pre-clinical studies: Epigenetic-modifying enzymes DNMT/TET and HAT/HDAC

Ischemic stroke (IS) remains a leading cause of mortality and disability worldwide, driven by genetic predispositions and environmental interactions, with epigenetics playing a pivotal role in mediating these processes. Specific modifying enzymes that regulate epigenetic changes have emerged as promising targets for IS treatment. DNA methyltransferases (DNMTs), ten-eleven translocation (TET) dioxygenases, histone acetyltransferases (HATs), and histone deacetylases (HDACs) are central to epigenetic regulation. These enzymes maintain a dynamic balance between DNA methylation/demethylation and histone acetylation/deacetylation, which critically influences gene expression and neuronal survival in IS. This review is based on both in vivo and in vitro experimental studies, exploring the roles of DNMT/TET and HAT/HDAC in IS, evaluating their potential as therapeutic targets, and discussing the use of natural compounds as modulators of these enzymes to develop novel treatment strategies.

Empagliflozin Alleviates Hepatic Steatosis and Oxidative Stress via the NRF1 Pathway in High-Fat Diet-Induced Mouse Model of Metabolic Dysfunction-Associated Steatotic Liver Disease

Empagliflozin (EMPA)-a sodium-glucose cotransporter type 2 inhibitor-reduces endoplasmic reticulum (ER) stress, oxidative stress, and inflammation during metabolic dysfunction-associated steatotic liver disease (MASLD) progression. However, the direct effects of EMPA on hepatic lipid metabolism and oxidative stress are unclear. Through the current study, we seek to explore the effects of EMPA on oxidative stress and related mechanisms in MASLD. To this end, MASLD was induced in C57BL/6J mice using a high-fat diet (HFD); nuclear respiratory factor 1 (NRF1) was downregulated via viral transduction (AAV8-shNrf1). Glucose homeostasis and liver histology were assessed, and oxidative stress and inflammation were measured. HFD-fed mice-derived liver tissue samples exhibited more lipid droplets, higher triglyceride levels, and elevated oxidative and ER stress than chow diet (CD)-fed mice. EMPA attenuated HFD-induced liver oxidative and ER stress. Additionally, the HFD significantly decreased NRF1 and Sirtuin (SIRT)7 expression compared with CD, which was rescued by EMPA treatment. However, these results did not affect insulin resistance or lipid synthesis-related changes upon EMPA treatment in the Nrf1-knockdown mice. Furthermore, EMPA alleviated HFD-induced hepatic steatosis and oxidative stress; however, these effects were lost in Nrf1-knockdown mice. Collectively, the results of this study suggest that EMPA ameliorates MASLD by reducing steatosis and attenuating oxidative stress via NRF1.

A Novel Aptamer-Based Fluorescent Biosensor for Imaging SIRT2 in Live Cells and Screening Its Modulators

Sirtuin 2 (SIRT2) is involved in the pathological processes of many diseases and is especially regarded as a potential therapeutic target for diabetes and neurodegenerative diseases. Imaging SIRT2 protein in live cells has important value for rapidly detecting SIRT2 and high-throughput screening SIRT2 modulators. As far as we know, there has been no method for imaging SIRT2 in live cells up to now. Here, we present a novel aptamer (Apt)-based "turn-on" fluorescent biosensor for imaging SIRT2 in live cells. To develop the recognition element of the biosensor, our work first discovered 12 aptamers (Apt) with high affinity to SIRT2 (Kd = 123.3-154.5 nM) using the magnetic beads-based systemic evolution of ligands by exponential enrichment (MB-SELEX) and selected Apt 45 (Kd = 123.3 nM) to fabricate the "turn-on" fluorescent biosensor, FAM-Apt 45/Black Hole Quencher1 (BHQ1)-cDNA/Au nanospheres, which had excellent specificity and low cytotoxicity. The experiment results demonstrated that the biosensor could image SIRT2 in three different cell lines, including Schwann, H9c2, and HUVECs cells. Further, we established a platform for screening SIRT2 modulators with the biosensor and discovered three SIRT2 modulators (astragaloside II, chlorogenic acid, and tanshinone IIA) that could increase SIRT2 levels in Schwann cells damaged by high glucose and lipid. This work provides an aptamer-based fluorescent biosensor for high-throughput screening of protein modulators at the cellular level, which could be a universal approach to screening aimed protein modulators by replacing the corresponding aptamer.

Induced Pluripotent Stem Cells-Based Regenerative Therapies in Treating Human Aging-Related Functional Decline and Diseases

A significant increase in life expectancy worldwide has resulted in a growing aging population, accompanied by a rise in aging-related diseases that pose substantial societal, economic, and medical challenges. This trend has prompted extensive efforts within many scientific and medical communities to develop and enhance therapies aimed at delaying aging processes, mitigating aging-related functional decline, and addressing aging-associated diseases to extend health span. Research in aging biology has focused on unraveling various biochemical and genetic pathways contributing to aging-related changes, including genomic instability, telomere shortening, and cellular senescence. The advent of induced pluripotent stem cells (iPSCs), derived through reprogramming human somatic cells, has revolutionized disease modeling and understanding in humans by addressing the limitations of conventional animal models and primary human cells. iPSCs offer significant advantages over other pluripotent stem cells, such as embryonic stem cells, as they can be obtained without the need for embryo destruction and are not restricted by the availability of healthy donors or patients. These attributes position iPSC technology as a promising avenue for modeling and deciphering mechanisms that underlie aging and associated diseases, as well as for studying drug effects. Moreover, iPSCs exhibit remarkable versatility in differentiating into diverse cell types, making them a promising tool for personalized regenerative therapies aimed at replacing aged or damaged cells with healthy, functional equivalents. This review explores the breadth of research in iPSC-based regenerative therapies and their potential applications in addressing a spectrum of aging-related conditions.

Canagliflozin potentially promotes renal protection against glycerol-induced acute kidney injury by activating the AMPK/SIRT1/FOXO-3a/PGC-1α and Nrf2/HO-1 pathways

The reno-protective potential of canagliflozin (Cana), an inhibitor of the sodium glucose-linked co-transporter-2 (SGLT-2), has been demonstrated in different models of kidney injury. However, its potential role in preventing glycerol (Gly)-induced acute kidney injury (AKI) remains to be divulged. Therefore, the aim of this study is to investigate the potential reno-protective effect of Cana and its underlying mechanism in a rat model of Gly-induced AKI. Rats were randomly allocated into five groups: normal, Gly, Gly pretreated with 10 mg/kg Cana, Gly pretreated with Cana 25 mg/kg, and normal pretreated with Cana 25 mg/kg for 14 consecutive days. Pretreatment with Cana improved renal structure and enhanced kidney functions manifested by reducing serum creatinine and blood urea nitrogen, as well as renal contents of neutrophil gelatinase-associated lipocalin and kidney injury molecule. Moreover, Cana signified its anti-inflammatory effect by reducing the Gly-induced elevation in renal contents of nuclear factor-κB and interleuκin-6. Additionally, Cana augmented the defense enzymatic antioxidants superoxide dismutase (SOD), manganese-SOD, and heme oxygenase-1, besides increasing the protein expression of the antioxidant transcription factor nuclear factor erythroid 2-related factor 2 to point for its ability to correct redox balance. Cana also upregulated the protein expression of the 5' adenosine monophosphate-activated protein kinase (AMPK), Sirtuin1 (SIRT1), Forkhead box protein O3 (FOXO-3a), and peroxisome proliferator-activated receptor-gamma coactivator 1α (PGC-1α), as well as the transcriptional activity of growth arrest and DNA damage-inducible protein alpha (GAAD45a). In conclusion, Cana demonstrated potentially novel reno-protective mechanisms and mitigated the consequences of AKI through its antioxidant and anti-inflammatory properties, partially by activating the AMPK/SIRT1/FOXO-3a/PGC-1α pathway.

SIRT1-based therapy targets a gene program involved in mitochondrial turnover in a model of retinal neurodegeneration

Neurodegenerative diseases of the eye such as optic neuritis (ON) are hallmarked by retinal ganglion cell (RGC) loss and optic nerve degeneration leading to irreversible blindness. Therapeutic interventions enhancing expression or activity of SIRT1, an NAD+-dependent deacetylase, support, at least in part, survival of RGCs in the face of injury. Herein, we used mice with experimental autoimmune encephalomyelitis (EAE) which recapitulates axonal and neuronal damages characteristic of ON to identify gene regulatory networks affected by constitutive ubiquitous Sirt1 expression in SIRT1 knock-in mice and wild-type mice upon targeted adeno-associated virus (AAV)-mediated SIRT1 expression in RGCs. RNA seq data analysis showed that the most upregulated genes in EAE mouse retinas include those involved in inflammation, immune response, apoptosis, and mitochondrial turnover. The latter includes genes regulating mitophagy (e.g., Atg4), mitochondrial transport (e.g., Ipo- 6, Xpo- 6), and mitochondrial localization (e.g., Chrna4, Scn9a). The constitutive or RGC-targeted SIRT1 overexpression in EAE mice upregulated the expression of non-mitochondrial genes such as Ecel1 and downregulated the expression of mitophagy genes (e.g., Atg2b, Arifip1) which were upregulated by EAE alone. Thus, SIRT1 induces neuroprotection by, at least in part, balancing mitochondrial biogenesis and mitophagy and/or enhancing mitochondrial self-repair to preserve the bioenergetic capacity of RGCs.

SETDB1 recruits CBX3 to regulate the SIRT4/PTEN axis, inhibiting autophagy and promoting ischemia-reperfusion-induced kidney injury

Ischemia-reperfusion (I/R) injury is a significant factor in the development of acute kidney injury (AKI), particularly in clinical scenarios, such as kidney transplantation, cardiac surgery, and severe hypotension. Autophagy, a critical process that eliminates damaged cellular components, has been shown to mitigate I/R injury by reducing oxidative stress and enhancing cell survival. However, when autophagy is disrupted, it can exacerbate kidney damage. Elucidating the role of autophagy in I/R injury is essential for uncovering the molecular mechanisms driving AKI and could facilitate the development of autophagy-based therapies. Protein expression levels were analyzed through western blot, immunohistochemistry (IHC), and immunofluorescence (IF) staining techniques. Interactions between SIRT4, SETDB1, and CBX3 were explored using chromatin immunoprecipitation (ChIP), sequential ChIP (ChIP-reChIP), and co-immunoprecipitation (Co-IP) assays. The association between SIRT4 and PTEN was also examined via Co-IP. Transmission electron microscopy (TEM) was employed to visualize autophagosomes. Furthermore, an in vivo rat model of I/R injury was developed for validation of the findings. Sirtuin 4 (SIRT4) expression was reduced, and autophagy was impaired during I/R injury. Moreover, SIRT4 interacted with phosphatase and tensin homolog (PTEN) to regulate its expression. Furthermore, SET domain bifurcated histone lysine methyltransferase 1 (SETDB1) mediated histone H3 lysine 9 trimethylation (H3K9me3) modifications and recruited chromobox protein homolog 3 (CBX3) to the SIRT4 promoter, leading to the repression of SIRT4 expression in kidney proximal tubular cells. Importantly, SETDB1 knockdown upregulated SIRT4, decreased PTEN expression, promoted autophagy, and protected rats against I/R injury in vivo. SETDB1 recruits CBX3 to regulate the SIRT4/PTEN axis, inhibiting autophagy and promoting I/R-induced kidney injury. These results suggest that targeting the SETDB1-SIRT4 axis could offer a novel therapeutic strategy to mitigate renal damage in I/R-induced AKI.

The role of ubiquitination and deubiquitination in the pathogenesis of non-alcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases and is closely associated with metabolic abnormalities. The causes of NAFLD are exceedingly complicated, and it is known that a variety of signaling pathways, endoplasmic reticulum stress, and mitochondrial dysfunction play a role in the pathogenesis of NAFLD. Recent studies have shown that ubiquitination and deubiquitination are involved in the regulation of the NAFLD pathophysiology. Protein ubiquitination is a dynamic and diverse post-translational alteration that affects various cellular biological processes. Numerous disorders, including NAFLD, exhibit imbalances in ubiquitination and deubiquitination. To highlight the significance of this post-translational modification in the pathogenesis of NAFLD and to aid in the development of new therapeutic approaches for the disease, we will discuss the role of enzymes involved in the processes of ubiquitination and deubiquitination, specifically E3 ubiquitin ligases and deubiquitinating enzymes that are important in the regulation of NAFLD.

Lead-Structure-Based Rigidization Approach to Optimize SirReal-Type Sirt2 Inhibitors

Sirtuins are involved in cellular processes in multiple ways. Therefore, the development of potent and selective Sirt2 inhibitors provides an important contribution to understanding physiological and pathophysiological mechanisms, particularly for the research and treatment of cancer and neurodegenerative diseases. Based on established SirReal-type lead inhibitors, further selective Sirt2 inhibitors were synthesized in a docking-guided rigidization approach, and the knowledge regarding requirements and properties of the Sirt2-binding pocket was expanded by means of a comprehensive SAR study. Naphthalene derivative FM69 emerged from the screening as the most potent rigidized inhibitor, which, with an IC50 value of 0.15 µM against Sirt2, represents a promising foundation for the further development of novel potent and selective Sirt2 inhibitors based on the presented rigidization strategy.

Acetylation of Hsc70 at K512 inhibits goat ovarian granulosa cell senescence by restoring chaperone-mediated autophagy

Nonhistone acetylation plays a crucial role in key cellular processes associated with ageing, such as autophagy. Heat shock cognate protein 70 (Hsc70), a vital chaperone protein for chaperone-mediated autophagy (CMA), exerts a molecular chaperone function that is regulated by its acetylation status. However, the effects of this acetylation on CMA and granulosa cell senescence remain unclear. This study investigated the effects of Hsc70 acetylation on CMA activity and senescence in goat ovarian granulosa cells (GCs). Notably, Hsc70 acetylation was found to mitigate granulosa cell senescence and promote CMA activity. Mass spectrometry analysis identified Hsc70 K512 as the acetylation site, and Sirtuin 2 (Sirt2) was found to catalyze the deacetylation of this site. In addition, Hsc70 expression and CMA activity were significantly reduced in ageing ovaries and under oxidative stress conditions. Subsequent experiments revealed that deacetylated Hsc70 increased the early and late apoptotic rates of GCs and inhibited CMA activity. Functionally, acetylation of the Hsc70 K512 site alleviates the ageing of GCs. In conclusion, this study elucidates the molecular mechanism through which Hsc70 K512 acetylation alleviates cell senescence by enhancing CMA activity in goat ovarian GCs, providing novel insights and potential intervention targets for female mammalian reproduction.

Sirtuin 2 inhibitor AGK2 exerts antiviral effects by inducing epigenetic suppression of hepatitis B virus covalently closed circular DNA through recruitment of repressive histone lysine methyltransferases and reduction of cccDNA

Chronic hepatitis B virus (HBV) infection continues to be a global health concern because current treatments such as interferon-α and nucleos(t)ide analogs cannot fully eliminate the virus due to persistence of covalently closed circular DNA (cccDNA) and integrated HBV DNA. Earlier research suggests that AGK2, a selective SIRT2 inhibitor, suppresses HBV replication by modifying key signaling pathways. This study aimed to further explore the anti-HBV effects of AKG2, particularly its effects on the epigenetic landscape of cccDNA. HBV-transfected and -infected cells were used to assess the impact of AGK2 on viral replication. Changes in SIRT2 expression and α-tubulin acetylation (SDS-PAGE-immunoblotting), core particle formation (native agarose gel electrophoresis and immunoblotting), HBV RNA (northern blotting) and DNA (Southern blotting) synthesis, and cccDNA levels (Southern blotting) were measured. Chromatin immunoprecipitation assays were performed to examine deposition of transcriptionally repressive epigenetic markers on cccDNA. AGK2 reduced expression of SIRT2, increased acetylated α-tubulin levels, and reduced synthesis of HBV RNA and DNA. Importantly, AGK2 also reduced cccDNA levels and increased deposition of repressive histone markers H4K20me1, H3K27me3, and H3K9me3 on cccDNA, mediated by histone lysine methyltransferases such as PR-Set7, EZH2, SETDB1, and SUV39H1. Additionally, there was a reduction in recruitment of RNA polymerase II and acetylated H3 to cccDNA, indicating that AGK2 enhances transcriptional repression. AGK2 suppresses HBV replication through direct antiviral actions, and by epigenetic modulation of cccDNA, indicating that using AGK2 to target SIRT2 and associated epigenetic regulators shows promise as a functional cure for chronic hepatitis B.

SIRT6 Overexpression Enhances Diabetic Foot Ulcer Healing via Nrf2 Pathway Activation

Sirtuin-6 (SIRT6) has a pivotal role in a wide array of cellular biological functions and is linked to the progression of various diseases. Previous findings have identified SIRT6 as a protective modulator against numerous diabetic complications. However, whether SIRT6 exerts a protective role in diabetic foot ulcer (DFU) remains unstudied. This work established a rat model of DFU and evaluated the possible role of SIRT6 in mediating the wound healing in DFU. Marked reductions in SIRT6 levels were observed in wound samples from DFU patients and rats. Increasing SIRT6 expression in wound tissues remarkably decreased wound area, accelerated epithelialisation, increased collagen deposition and improved angiogenesis. Moreover, up-modulation of SIRT6 relieved the oxidative stress and inflammation in DFU rats. The increase of SIRT6 in cultured vascular endothelial cells restrained cell apoptosis, oxidative stress and inflammation elicited by high glucose (HG). HG-impaired migration capacity and angiogenesis of vascular endothelial cells was also recovered by increasing SIRT6 expression. Mechanism research revealed that SIRT6 overexpression reinforced the activation of the Nrf2 pathway in wound tissues of DFU rats and HG-exposed vascular endothelial cells. Pharmacological suppression of Nrf2 reversed the protective effect of SIRT6 overexpression on HG-triggered endothelial dysfunction. The findings of this work indicate that the positive role of SIRT6 in DFU wound healing is related to Nrf2 activation which contributes to the suppression of oxidative stress and inflammation and the improvement of angiogenesis in vascular endothelial cells. This study highlights the previously unaddressed role of SIRT6 in DFU wound healing, providing novel insights into its protective functions. The findings hold significant clinical value by identifying SIRT6 as a promising therapeutic target for improving DFU wound healing.

Activation of SIRT1 Reduces Renal Tubular Epithelial Cells Fibrosis in Hypoxia Through SIRT1-FoxO1-FoxO3-Autophagy Pathway

Heart failure-induced renal tubular epithelial cell fibrosis is an important pathological process that leads to chronic kidney disease. This study is to investigate the regulatory mechanism of over-expression or knock-down SIRT1 gene, alleviating hypoxia-induced HK2 cell fibrosis in heart failure. The focus is on the SIRT1-FoxO1-FoxO3-Autophagy pathway. In vitro experiments are performed by HK2cell line to simulate the normal oxygen state (Normoxia) and the hypoxia state (Hypoxia) caused by heart failure, SIRT1 gene over-expression by transfected vectors, knock-down and Rapamycin (RAPA)-induced cellular autophagy, and the cell models are divided into four subgroups, named control group, oeSIRT1, siSIRT1 and siSIRT1+RAPA. Western blotting (WB), real-time qPCR, immunofluorescence (IF), ELISA, and transmission electron microscopy are used to quantitatively or semi-quantitatively analyze the expression of FoxO1, FoxO3, SIRT1, Beclin1, LC-3, α-SMA, E- Cadherin, and collagen-I in cells or supernatants. It is demonstrated that activation of SIRT1 regulates the expression and activity of FoxO1 and FoxO3, thereby affecting autophagy. This modulation leads to a reduction in HK2 fibrosis markers (α-SMA and E-cadherin) and extracellular matrix deposition (collagen I), which ultimately attenuates renal tubular epithelial cell fibrosis. These findings provide new insights into potential therapeutic strategies for treating heart failure-induced renal tubular epithelial cell fibrosis by targeting the SIRT1-FoxO1-FoxO3-Autophagy pathway.

SIRT5 Regulates Lipid Deposition in Goat Preadipocytes via PI3K-Akt and MAPK Signaling Pathways

Silent Information Regulator 5 (SIRT5) has been established as a crucial regulator of cellular alanylation modification. Furthermore, accumulating evidence suggests that SIRT5 plays a significant regulatory role in key metabolic pathways, including glycolysis, the tricarboxylic acid (TCA) cycle, and fatty acid oxidation, all of which are closely associated with cellular lipid metabolism. Despite these advancements, the specific role of SIRT5 in regulating intramuscular fat (IMF) deposition in goats, as well as the underlying molecular mechanisms, remains largely unexplored. In this study, we cloned the complete coding sequence of the goat SIRT5 gene and, through amino acid sequence alignment, demonstrated its closest phylogenetic relationship with sheep. Additionally, we characterized the higher expression of SIRT5 during the differentiation of goat intramuscular precursor adipocytes. The silencing of SIRT5 by siRNA-mediated knockdown significantly upregulated the expression of lipogenesis-related genes and enhanced lipid deposition in goat intramuscular preadipocytes. Concurrently, SIRT5 deficiency led to the inhibition of cell proliferation and a marked reduction in apoptosis. Interestingly, although overexpression of SIRT5 promoted cell proliferation, it did not significantly alter lipid deposition in goat intramuscular precursor adipocytes. RNA sequencing (RNA-seq) analysis identified a total of 106 differentially expressed genes (DEGs) following SIRT5 silencing in goat preadipocytes, predominantly involved in the Focal adhesion, HIF-1, PI3K-Akt, and MAPK signaling pathways by KEGG pathway enrichment analysis. Notably, we successfully reversed the phenotypic effects observed in SIRT5 knockdown goat precursor adipocytes by inhibiting the PI3K-Akt and MAPK signaling pathways using the AKT inhibitor LY294002 and the p38 MAPK pathway inhibitor PD169316, respectively. In conclusion, our findings demonstrated that SIRT5 may modulate intramuscular fat deposition in goats through PI3k-Akt and MAPK signaling pathways. These results expand the gene regulatory network associated with IMF formation and provide a theoretical foundation for improving meat quality by targeting IMF deposition.

SIRT3/6/7: promising therapeutic targets for pulmonary fibrosis

Pulmonary fibrosis is a chronic progressive fibrosing interstitial lung disease of unknown cause, characterized by excessive deposition of extracellular matrix, leading to irreversible decline in lung function and ultimately death due to respiratory failure and multiple complications. The Sirtuin family is a group of nicotinamide adenine dinucleotide (NAD+) -dependent histone deacetylases, including SIRT1 to SIRT7. They are involved in various biological processes such as protein synthesis, metabolism, cell stress, inflammation, aging and fibrosis through deacetylation. This article reviews the complex molecular mechanisms of the poorly studied SIRT3, SIRT6, and SIRT7 subtypes in lung fibrosis and the latest research progress in targeting them to treat lung fibrosis.

Stem Cell Therapy Modulates Molecular Cues of Vasogenic Edema Following Ischemic Stroke: Role of Sirtuin-1 in Regulating Aquaporin-4 Expression

BACKGROUND

Conventional post-stroke edema management strategies are limitedly successful as in multiple cases of hemorrhagic transformation is being reported. Clinically, acute-ischemic-stroke (AIS) intervention by endovascular mesenchymal stem cells (MSCs) have shown benefits by altering various signaling pathways. Our previous studies have reported that intra-arterial administration of 1*105 MSCs (IA-MSCs) were beneficial in alleviating post-stroke edema by modulating PKCδ/MMP9/AQP4 axis and helpful in preserving the integrity of blood-brain-barrier (BBB). However, the role of mitochondrial dysfunction and ROS generation post-AIS cannot be overlooked in context to the alteration of the BBB integrity and edema formation through the activation of inflammatory pathways. The anti-inflammatory activity of IA-MSCs in stroke has been reported to be regulated by sirtuin-1 (SIRT-1). Hence, the relationship between SIRT-1 and AQP4 towards regulation of post-stroke edema needs to be further explored. Therefore, the present study deciphers the molecular events towards AQP4 upregulation, mitochondrial dysfunction and BBB disruption in context to the modulation of SIRT-1/PKCδ/NFκB loop by IA-MSCs administration.

METHODS

Ovariectomized SD rats were subjected to focal ischemia. SIRT-1 activator, SIRT-1 inhibitor, NFkB inhibitor and IA-MSCs were administered at optimized dose. At 24 h of reperfusion, behavioral tests were performed, and brains were harvested following euthanasia for molecular studies.

RESULTS

IA-MSCs downregulated AQP4, PKCδ and NFkB expression, and upregulated SIRT-1 expression. SIRT-1 upregulation renders mitochondrial protection via reduction of oxidative stress resulting in BBB protection.

CONCLUSION

IA-MSCs can modulate SIRT-1 mediated AQP4 expression via mitochondrial ROS reduction and modification of NFkB transcriptional regulation.

SIRT7-mediated NRF2 deacetylation promotes antioxidant response and protects against chemodrug-induced liver injury

NRF2 has been recognized as a central hub that neutralizes ROS and restores intracellular redox balance. In addition to KEAP1 mediated ubiquitin-proteasome degradation, post-translational modifications of NRF2 are critical for regulating its nuclear translocation and activation but precise mechanisms underly this regulation remain elusive. In this study, we found that SIRT7 was sufficient and essential for NRF2 nuclear localization and activation. Knockdown of SIRT7 significantly impaired intercellular ROS homeostasis and increased apoptosis in response to oxidative stress including chemodrug treatment. SIRT7 interacted with NRF2 and induced its deacetylation, by which inhibited binding of NRF2 to KEAP1, enhanced NRF2 protein stability and promoted its nuclear translocation. SIRT7 induced NRF2 deacetylation at K443 and K518 sites. Lysine-arginine mutations of these sites (2KR NRF2) significantly reduced KEAP1/NRF2 binding, increased NRF2 nuclear translocation and target gene expression, decreased intercellular ROS level, whereas lysine-glutamine (2KQ) mutant showed similar subcellular localization and functions with WT. Knockdown SIRT7 in hepatocyte exacerbated Oxaliplatin (Oxa) induced hepatic injury and inflammation. While AAV8-NRF2-mediated hepatic NRF2 overexpression or NRF2 agonist significantly prevented Oxa-induced elevation of ALT levels, sinusoidal dilatation and inflammation in SIRT7HKO mice. Our data thus uncovered previously unidentified role of SIRT7 in modulating NRF2 nuclear localization and activation via deacetylation. Activating SIRT7 might offer protection against chemodrug-induced liver injury.

Schisandrin B Improves Mitochondrial Function and Inhibits HT22 Cell Apoptosis by Regulating Sirt3 Protein

Neurological diseases refer to pathological changes that occur in the brain, spinal cord, and peripheral nerves. Their etiologies are complex, treatment outcomes are poor, and prognoses are unfavorable. Therefore, how to improve the treatment efficacy of neurological diseases is an urgent problem to be addressed in current clinical practice. Schisandrin B, a commonly used traditional Chinese medicine in clinical settings, has anti-tumor, anti-inflammatory, and wound-healing promoting effects. However, there are relatively few studies on its application in the treatment of neurological diseases. In this study, HT22 nerve cells were cultured, and an injury model was constructed by applying H2O2 stimulation to explore the protective effect of Schisandrin B on these cells. The research results showed that compared with the H2O2 group, Schisandrin B could significantly increase the viability (30.872%) and migration ability (42.756%) of HT22 cells, and inhibit the apoptosis of HT22 cells (22.817%). Further exploration of the mechanism revealed that Schisandrin B regulated the mitochondrial dynamic balance and membrane potential level of HT22 cells by upregulating the expression of Sirt3 protein, enhanced the mitochondrial energy metabolism (with an increase of 53.411% in ATP production), and maintained the integrity of the quantity and structure of mitochondria, ultimately exerting a protective effect on HT22 cells.

Resveratrol in animal models of pancreatitis and pancreatic cancer: A systematic review with machine learning

BACKGROUND

Resveratrol (RES), a common type of plant polyphenols, has demonstrated promising therapeutic efficacy and safety in animal models of pancreatitis and pancreatic cancer. However, a comprehensive analysis of these data is currently unavailable. This study aimed to systematically review the preclinical evidence regarding RES's effects on animal models of pancreatitis and pancreatic cancer via meta-analyses and optimised machine learning techniques.

METHODS

Animal studies published from inception until June 30th 2024, were systematically retrieved and manually filtrated across databases including PubMed, EMBASE, Web of Science, Ovid MEDLINE, Scopus, and Cochrane Library. Methodological quality of the included studies was evaluated following the SYRCLE's RoB tool. Predefined outcomes included histopathology and relevant biochemical parameters for acute pancreatitis, and tumour weight/tumour volume for pancreatic cancer, comparing treatment and model groups. Pooled effect sizes of the outcomes were calculated using STATA 17.0 software. Machine learning techniques were employed to predict the optimal usage and dosage of RES in pancreatitis models.

RESULTS

A total of 50 studies comprising 33 for acute pancreatitis, 1 chronic pancreatitis, and 16 for pancreatic cancer were included for data synthesis after screening 996 records. RES demonstrated significant improvements on pancreatic histopathology score, pancreatic function parameters (serum amylase and lipase), inflammatory markers (TNF-α, IL-1β, IL-6, and pancreatic myeloperoxidase), oxidative biomarkers (malondialdehyde and superoxide dismutase), and lung injury (lung histopathology and myeloperoxidase) in acute pancreatitis models. In pancreatic cancer models, RES notably reduced tumour weight and volume. Machine learning highlighted tree-structured Parzen estimator-optimised gradient boosted decision tree model as achieving the best performance, identifying course after disease induction, total dosage, single dosage, and total number of doses as critical factors for improving pancreatic histology. Optimal single dosage was 20-105 mg/kg with 3 to 9 doses.

CONCLUSION

This study comprehensively demonstrates the therapeutic effects of RES in mitigating pancreatitis and pancreatic cancer in animal models. Anti-inflammatory, anti-oxidative, and anti-tumour growth properties are potential mechanisms of action for RES.

Zinc Alleviates Diabetic Muscle Atrophy via Modulation of the SIRT1/FoxO1 Autophagy Pathway Through GPR39

BACKGROUND

Muscle atrophy is a severe complication of diabetes, with autophagy playing a critical role in its progression. Zinc has been shown to alleviate hyperglycaemia and several diabetes-related complications, but its direct role in mediating diabetic muscle atrophy remains unclear. This study explores the potential role of zinc in the pathogenesis of diabetic muscle atrophy.

METHODS

In vivo, C57BL/6J mice were induced with diabetes by streptozotocin (STZ) and treated with ZnSO₄ (25 mg/kg/day) for six weeks. Gastrocnemius muscles were collected for histological analysis, including transmission electron microscopy (TEM). Serum zinc levels were measured by ICP-MS. Protein expression was evaluated using immunofluorescence (IF), immunohistochemistry (IHC) and Western blotting (WB). Bioinformatics analysis was used to identify key genes associated with muscle atrophy. In vitro, a high-glucose-induced diabetic C2C12 cell model was established and received ZnSO₄, rapamycin, SRT1720, TC-G-1008, or GPR39-CRISPR Cas9 intervention. Autophagy was observed by TEM, and protein expression was assessed by IF and WB. Intracellular zinc concentrations were measured using fluorescence resonance energy transfer (FRET).

RESULTS

In vivo, muscle atrophy, autophagy activation, and upregulation of SIRT1 and FoxO1, along with downregulation of GPR39, were confirmed in the T1D group. ZnSO₄ protected against muscle atrophy and inhibited autophagy (T1D + ZnSO₄ vs. T1D, all p < 0.0001), as evidenced by increased grip strength (212.40 ± 11.08 vs. 163.90 ± 10.95 gf), gastrocnemius muscle index (10.67 ± 0.44 vs. 8.80 ± 0.72 mg/g), muscle fibre cross-sectional area (978.20 ± 144.00 vs. 580.20 ± 103.30 μm2), and serum zinc levels (0.2335 ± 0.0227 vs. 0.1561 ± 0.0123 mg/L). ZnSO₄ down-regulated the expression of Atrogin-1 and MuRF1, and decreased the formation of autophagosomes in the gastrocnemius muscle of T1D mice (all p < 0.0001). RNA-seq analysis indicated activation of the SIRT1/FoxO1 signalling pathway in diabetic mice. ZnSO₄ down-regulated LC3B, SIRT1 and FoxO1, while upregulating P62 and GPR39 (all p < 0.05). In vitro, muscle atrophy, autophagy activation, and down-regulation of GPR39 were confirmed in the diabetic cell model (all p < 0.05). Both ZnSO₄ and TC-G-1008 down-regulated Atrogin-1, LC3B, SIRT1, and FoxO1, and up-regulated P62 and GPR39, inhibiting autophagy and improving muscle atrophy (all p < 0.05). The beneficial anti-atrophic effects of ZnSO₄ are diminished following treatment with SRT1720 or RAPA. Upon GPR39 knockout, SIRT1, FoxO1, and Atrogin-1 were upregulated, while P62 was downregulated. Intracellular zinc concentrations in ZnSO₄-treated group remained unchanged (p > 0.05), indicating that zinc supplementation did not affect zinc ion entry but acted through the cell surface receptor GPR39.

CONCLUSION

ZnSO4 inhibits excessive autophagy in skeletal muscle and alleviates muscle atrophy in diabetic mice via the GPR39-SIRT1/FoxO1 axis. These findings suggest that zinc supplementation may offer a potential therapeutic strategy for managing diabetic muscle atrophy.

Dihydromyricetin regulates the miR-155-5p/SIRT1/VDAC1 pathway to promote liver regeneration and improve alcohol-induced liver injury

BACKGROUND

Alcohol-related liver disease (ALD) has become an increasingly serious global health issue. In recent years, growing evidence has highlighted the restoration of liver regenerative capacity as an effective therapeutic strategy for improving ALD. Previous studies have demonstrated the protective effect of dihydromyricetin (DMY) in alcohol-induced liver injury, but its pharmacological role in ALD-related liver regeneration impairment remains poorly understood.

OBJECTIVE

This study aims to explore the therapeutic potential and molecular mechanisms of DMY in the context of liver regeneration impairment in ALD.

METHODS

The classic Lieber-DeCarli alcohol liquid diet was used to establish an ALD model in vivo. DMY (75 and 150 mg/kg/day) and silybin (200 mg/kg) were administered for 7 weeks to assess the hepatoprotective effects of DMY. First, biochemical markers and liver histopathology were used to evaluate liver inflammation and steatosis in ALD mice. Second, we explored the potential molecular mechanisms by which DMY improves ALD through serum untargeted metabolomics, hepatic transcriptomics, and single-cell sequencing data. Furthermore, in vivo and in vitro experiments, combined with Western blotting, dual-luciferase reporter assays, and immunofluorescence, were conducted to elucidate the protective mechanisms underlying DMY's effects on ALD.

RESULTS

In vivo studies showed that DMY significantly ameliorated ALT/AST abnormalities, liver inflammation, and steatosis in ALD mice. Multi-omics and bioinformatics analyses revealed that DMY may exert its anti-ALD effects by regulating the miR-155-5p/SIRT1/VDAC1 pathway, thereby mitigating cellular senescence. Notably, knockdown of miR-155 provided partial protection against ethanol-induced liver damage. Additionally, clinical ALD samples and in vivo and in vitro experiments further confirmed that excessive alcohol exposure induces the production of miR-155-5p in liver Kupffer cells. miR-155-5p targets and inhibits SIRT1, promoting the expression of mitochondrial VDAC1, leading to mitochondrial DNA leakage, thereby accelerating hepatocyte senescence and inflammation. However, DMY improved the disruption of the miR-155-5p/SIRT1/VDAC1 pathway and hepatocyte senescence, thereby restoring liver regenerative function and exerting anti-ALD effects.

CONCLUSION

In this study, we provide the first evidence that DMY improves liver inflammation and cellular senescence by regulating the miR-155-5p/SIRT1/VDAC1 positive feedback loop, promoting liver regeneration to improve ALD. In summary, our work provides important research evidence and theoretical support for DMY as a promising candidate drug for the prevention and treatment of ALD.

Mitochondrial Dysfunction-Molecular Mechanisms and Potential Treatment approaches of Hepatocellular Carcinoma

Primary liver cancer (PLC), also known as hepatocellular carcinoma (HCC), is a common type of malignant tumor of the digestive system. Its pathological form has a significant negative impact on the patients' quality of life and ability to work, as well as a significant financial burden on society. Current researches had identified chronic hepatitis B virus infection, aflatoxin B1 exposure, and metabolic dysfunction-associated steatotic liver disease (MASLD) as the main causative factors of HCC. Numerous variables, including inflammatory ones, oxidative stress, apoptosis, autophagy, and others, have been linked to the pathophysiology of HCC. On the other hand, autoimmune regulation, inflammatory response, senescence of the hepatocytes, and mitochondrial dysfunction are all closely related to the pathogenesis of HCC. In fact, a growing number of studies have suggested that mitochondrial dysfunction in hepatocytes may be a key factor in the pathogenesis of HCC. In disorders linked to cancer, mitochondrial dysfunction has gained attention in recent 10 years. As the primary producer of adenosine triphosphate (ATP) in liver cells, mitochondria are essential for preserving cell viability and physiological processes. By influencing multiple pathological processes, including mitochondrial fission/fusion, mitophagy, cellular senescence, and cell death, mitochondrial dysfunction contributes to the development of HCC. We review the molecular mechanisms of HCC-associated mitochondrial dysfunction and discuss new directions for quality control of mitochondrial disorders as a treatment for HCC.