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Aims: The interaction between pancreatic islets and skeletal muscle plays a pivotal role in the development of insulin resistance. The present study aimed to elucidate the impact of non‐hormonal molecules from islets on the insulin sensitivity of skeletal muscle cells.Materials and Methods:We developed a mouse model of obesity through a high‐fat diet, assessing glucose tolerance and conducting miRNA sequencing on skeletal muscle samples. An in vitro model was established by treating cells with palmitic acid, and exosomes in the supernatant were characterized using scanning electron microscopy and CD63 expression analysis. Intracellular miR‐204‐5p levels were quantified by RT‐PCR.Results: Our in vivo model demonstrated a robust correlation between miR‐204‐5p level alterations and obesity‐induced insulin resistance. Elevated fatty acid levels were observed to increase miR‐204‐5p in both skeletal muscle and islets. In cellular studies, palmitic acid increased miR‐204‐5p in MIN‐6 islet β‐cells but not in C2C12 skeletal muscle cells. Exosomes containing miR‐204‐5p, secreted by palmitic acid‐treated MIN6 cells, were identified through morphological examination, immunoblotting for the exosomal marker CD63, and intraexosomal miR‐204‐5p level measurement. C2C12 cells were shown to uptake islet‐derived miR‐204‐5p exosomes, as evidenced by the uptake of Exo‐Red labeled exosomes. TargetScan analysis identified a highly conserved binding site for miR‐204‐5p in the 3' UTR of Sirt mRNA. Functional studies indicated that miR‐204‐5p overexpression reduced glucose consumption and uptake in C2C12 cells, decreased Sirt expression, and impaired insulin signaling, as evidenced by reduced Akt phosphorylation and membrane Glut4 levels.Conclusions: Our findings reveal that miR‐204‐5p contributes to the development of insulin resistance in obesity and acts as a signaling molecule in the crosstalk between pancreatic islets and skeletal muscle. [ABSTRACT FROM AUTHOR]

Background: Vasculogenic therapies explored for the treatment of peripheral artery disease (PAD) have encountered minimal success in clinical trials. Addressing this, B55α, an isoform of protein phosphatase 2A (PP2A), emerges as pivotal in vessel remodeling through activation of hypoxia-inducible factor 1α (HIF-1α). This study delves into the pharmacological profile of VCE-004.8 (Etrinabdione) and evaluates its efficacy in a preclinical model of critical limb ischemia, with a focus on its potential as a PP2A/B55α activator to induce angiogenesis and arteriogenesis. Methods: Vascular endothelial cells were used for in vitro experiments. Aorta ring assay was performed to explore sprouting activity. Matrigel plug-in assay was used to assess the angiogenic potential. Critical limb ischemia (CLI) in mice was induced by double ligation in the femoral arteria. Endothelial vascular and fibrotic biomarkers were studied by immunohistochemistry and qPCR. Arteriogenesis was investigated by microvascular casting and micro-CT. Proteomic analysis in vascular tissues was analyzed by LC–MS/MS. Ex-vivo expression of B55α and biomarkers were investigated in artery samples from PAD patients. Results: VCE-004.8 exhibited the ability to induce B55α expression and activate the intersecting pathways B55α/AMPK/Sirtuin 1/eNOS and B55α/PHD2/HIF-1α. VCE-004.8 prevented OxLDL and H2O2-induced cytotoxicity, senescence, and inflammation in endothelial cells. Oral VCE-004.8 increased aorta sprouting in vitro and angiogenesis in vivo. In CLI mice VCE-004.8 improved collateral vessel formation and induced endothelial cells proliferation, angiogenic gene expression and prevented fibrosis. The expression of B55α, Caveolin 1 and Sirtuin-1 is reduced in arteries from CLI mice and PAD patient, and the expression of these markers was restored in mice treated with VCE-004.8. Conclusions: The findings presented in this study indicate that Etrinabdione holds promise in mitigating endothelial cell damage and senescence, while concurrently fostering arteriogenesis and angiogenesis. These observations position Etrinabdione as a compelling candidate for the treatment of PAD, and potentially other cardiovascular disorders. [ABSTRACT FROM AUTHOR]

Chronic limb-threatening ischemia (CLTI) significantly increases the risk of major adverse limb events (MALE) and major adverse cardiac events (MACE) after lower extremity revascularization (LER). This study aims to identify novel biomarkers that help to further reduce the risk of postoperative cardiovascular complications. In this prospective, nonrandomized, observational study, baseline serum levels of sirtuin 1 (SIRT1) were assessed in 147 diabetic patients scheduled for LER due to CLTI, and participants were followed for the occurrence of MALE and MACE over 12 months. Fifty-three patients experienced MALE, and 33 experienced MACE within the follow-up period. Lower baseline SIRT1 levels were significantly associated with an increased risk of MALE and MACE, independent of other risk factors. The ROC curve analysis identified a SIRT1 cutoff of 3.79 ng/mL for predicting the risk of MALE. Moreover, incorporating SIRT1 into predictive models significantly enhanced the accuracy of predicting adverse outcomes. Results suggest serum SIRT1 is a potential independent marker for predicting MALE and MACE in diabetic patients with CLTI undergoing LER. Further research is needed to clarify the mechanistic pathways in which SIRT1 may influence cardiovascular outcomes, and the role of this novel biomarker in the management of PAD and CLTI among patients with diabetes. [ABSTRACT FROM AUTHOR]

Aging is a natural process that is also influenced by some factors like the food someone eats, lifestyle decisions, and impacts on general health. Despite the recognized role of nutrition in modulating the molecular and cellular mechanisms underlying aging, there is a lack of comprehensive exploration into potential interventions that can effectively mitigate these effects. In this study, we investigated the potential anti-aging properties of vitamin D by examining its interactions with key molecular targets involved in aging-related pathways. By using molecular docking and dynamics techniques, we evaluate the interactions and stability of vitamins D2 and D3 with key proteins involved in aging pathways, such as SIRT1, mTOR, AMPK, Klotho, AhR, and MAPK. Our results reveal promising binding affinities between vitamin D and SIRT1 forms, with energy values of −48.33 kJ/mol and −45.94 kJ/mol for vitamins D2 and D3, respectively, in aqueous environments. Moreover, molecular dynamics simulations revealed that the vitamin D3–SIRT1 complex exhibited greater stability compared with the vitamin D2–SIRT1 complex. The study calculated the solvation free energy to compare the solubility of vitamins D2 and D3 in water and various organic solvents. Despite their strong interactions with water, both vitamins exhibited low solubility, primarily due to the high energy cost associated with cavity formation in the aqueous environment. Compared with other solvents, water demonstrated particularly low solubility for both vitamins. This suggested that vitamins D2 and D3 preferred binding to aging receptors over dissolving in bulk aqueous environments, supporting their strong therapeutic interactions with these receptors. These findings shed light on the molecular mechanisms underlying vitamin D's potential anti-aging effects and lay the groundwork for developing nutraceuticals targeting aging and associated diseases. Understanding these mechanisms holds promise for future interventions aimed at promoting healthy aging and enhancing overall well-being. [ABSTRACT FROM AUTHOR]

Background: Acetaminophen (APAP) overdose can cause severe acute liver injury. Poly (ADP-ribose) polymerase 1 (PARP1) is a nuclear protease that senses DNA breaks and repairs damaged DNA. The role PARP1 plays in APAP-induced hepatotoxicity is still unclear. Materials and methods: The study was designed in two parts. First, the relationship between PARP1 expression and hepatotoxicity was investigated. Then, the inhibitor PJ34 was used to inhibit the activity of PARP1 and examined its effects. In particular, APAP, vehicle or PJ34 was intraperitoneally administered to mice. Serum transaminase levels were measured with commercial kits. Hematoxylin & eosin staining was used for histopathological observation of the liver. The protein levels of PARP1, poly (ADP-ribose), Sirtuin1 (Sirt1) and γ-H2AX were detected by western blotting. Results: In a dose- and time-dependent manner, APAP exposure resulted in the overactivation of PARP1 in the livers of mice. Posttreatment with PJ34 ameliorated changes in serum transaminase levels, and histopathological abnormalities. The protein expression of Sirt1 was elevated by PJ34, while that of PARP1, poly (ADP-ribose), and γ-H2AX was reduced due to PJ34 administration. Conclusion: Excessive APAP administration results in PARP1 overactivation, and its inhibition sheds light on the treatment of APAP-induced liver injury. [ABSTRACT FROM AUTHOR]

Abstract Chronic limb-threatening ischemia (CLTI) significantly increases the risk of major adverse limb events (MALE) and major adverse cardiac events (MACE) after lower extremity revascularization (LER). This study aims to identify novel biomarkers that help to further reduce the risk of postoperative cardiovascular complications. In this prospective, nonrandomized, observational study, baseline serum levels of sirtuin 1 (SIRT1) were assessed in 147 diabetic patients scheduled for LER due to CLTI, and participants were followed for the occurrence of MALE and MACE over 12 months. Fifty-three patients experienced MALE, and 33 experienced MACE within the follow-up period. Lower baseline SIRT1 levels were significantly associated with an increased risk of MALE and MACE, independent of other risk factors. The ROC curve analysis identified a SIRT1 cutoff of 3.79 ng/mL for predicting the risk of MALE. Moreover, incorporating SIRT1 into predictive models significantly enhanced the accuracy of predicting adverse outcomes. Results suggest serum SIRT1 is a potential independent marker for predicting MALE and MACE in diabetic patients with CLTI undergoing LER. Further research is needed to clarify the mechanistic pathways in which SIRT1 may influence cardiovascular outcomes, and the role of this novel biomarker in the management of PAD and CLTI among patients with diabetes.

Abstract Background Vasculogenic therapies explored for the treatment of peripheral artery disease (PAD) have encountered minimal success in clinical trials. Addressing this, B55α, an isoform of protein phosphatase 2A (PP2A), emerges as pivotal in vessel remodeling through activation of hypoxia-inducible factor 1α (HIF-1α). This study delves into the pharmacological profile of VCE-004.8 (Etrinabdione) and evaluates its efficacy in a preclinical model of critical limb ischemia, with a focus on its potential as a PP2A/B55α activator to induce angiogenesis and arteriogenesis. Methods Vascular endothelial cells were used for in vitro experiments. Aorta ring assay was performed to explore sprouting activity. Matrigel plug-in assay was used to assess the angiogenic potential. Critical limb ischemia (CLI) in mice was induced by double ligation in the femoral arteria. Endothelial vascular and fibrotic biomarkers were studied by immunohistochemistry and qPCR. Arteriogenesis was investigated by microvascular casting and micro-CT. Proteomic analysis in vascular tissues was analyzed by LC–MS/MS. Ex-vivo expression of B55α and biomarkers were investigated in artery samples from PAD patients. Results VCE-004.8 exhibited the ability to induce B55α expression and activate the intersecting pathways B55α/AMPK/Sirtuin 1/eNOS and B55α/PHD2/HIF-1α. VCE-004.8 prevented OxLDL and H2O2-induced cytotoxicity, senescence, and inflammation in endothelial cells. Oral VCE-004.8 increased aorta sprouting in vitro and angiogenesis in vivo. In CLI mice VCE-004.8 improved collateral vessel formation and induced endothelial cells proliferation, angiogenic gene expression and prevented fibrosis. The expression of B55α, Caveolin 1 and Sirtuin-1 is reduced in arteries from CLI mice and PAD patient, and the expression of these markers was restored in mice treated with VCE-004.8. Conclusions The findings presented in this study indicate that Etrinabdione holds promise in mitigating endothelial cell damage and senescence, while concurrently fostering arteriogenesis and angiogenesis. These observations position Etrinabdione as a compelling candidate for the treatment of PAD, and potentially other cardiovascular disorders.

Sirtuin 1 (SIRT1) is a histone/protein deacetylase in the cellular response to inflammatory, metabolic, and oxidative stressors. We previously reported that myeloid SIRT1 regulates the inflamed livers canonical pyroptosis cell death pathway. However, whether/how hepatocyte SIRT1 is engaged in programmed cell death in the cold-stressed liver remains uncertain. Here, we undertook translational studies in human and mouse orthotopic liver transplantation (OLT) to interrogate the significance of hepatocyte-specific SIRT1 in cold-stored donor livers and liver grafts after reperfusion. In the clinical arm of sixty human OLT patients, hepatic SIRT1 levels in cold-preserved donor livers correlated with the anti-apoptotic Bcl-2 expression. After reperfusion, improved OLT function was accompanied by hepatic SIRT1 levels negatively associated with cleaved caspase-3 expression. In the experimental arm, we compared FLOX-control with hepatocyte-specific SIRT1-KO livers after orthotopic transplantation into WT mouse recipients, parallel with primary murine hepatocyte cultures subjected to cold activation with/without knockdown of SIRT1, GSDME, and IL18Rβ. Indeed, hepatocyte SIRT1 deficiency upregulated apoptosis and GSDME-mediated programmed cell death, deteriorating hepatocellular function and shortening OLT survival. Augmented GSDME processing, accompanied by increased secretion of IL18 by stressed hepatocytes, was prominent in SIRT1-deficient, cold-stored livers. Hepatocyte SIRT1 expression regulated anti-apoptotic Bcl-2/XIAP proteins, suppressed cold stress-triggered apoptosis, and mitigated GSDME licensing to release IL18. Notably, consistent with the ability of IL18 to depress hepatocyte SIRT1 and Bcl-2/XIAP in vitro, IL18 neutralization in vivo prevented hepatocellular damage and restored the anti-apoptotic phenotype in otherwise injury-prone SIRT1-deficient OLTs. In conclusion, this translational study identifies a novel hepatocyte SIRT1-IL18 molecular circuit as a therapeutic target in the mechanism underpinning hepatocyte death pathways in human and mouse liver transplantation.

Vascular cognitive impairment (VCI) denotes a wide range of cognitive deficiencies resulting from cerebrovascular risk factors and cerebrovascular diseases. Sirtuin 1 (SIRT1), as a deacetylase, can mediate the deacetylation of histones and non-histone proteins. It is involved in regulating multiple pathophysiological processes of VCI, including neuroinflammation reduction, oxidative stress inhibition, cell apoptosis decrease, and blood-brain barrier protection, serving as a target for VCI treatment. This paper summarizes SIRT1 and the molecular mechanisms of targeting SIRT1 in order to provide a reference for the clinical treatment of VCI.

Objective: To explore whether thrombopoietin can exert a protective effect against doxorubicin-induced cardiotoxicity by modulating the sirtuin 1 (SIRT1) signaling pathway. Methods: H9c2 cell viability was determined by CCK-8 and cardiomyocyte apoptosis was detected by TUNEL assay. The protein expressions of SIRT1 and p38 MAPK were measured by Western blot. RT-qPCR was also used to determine S1RT1 mRNA expression. In addition, intracellular reactive oxygen species levels and antioxidant enzyme activities were evaluated. Results: Thrombopoietin treatment reversed doxorubicin-induced decline in H9c2 cell viability. It also increased SIRT1 and decreased p-p38 MAPK protein expressions. In addition, thrombopoietin significantly attenuated doxorubicin-induced apoptosis and oxidative stress, and enhanced antioxidant enzyme activities. However, silencing S1RT1 abrogated the protective effects of thrombopoietin, as evidenced by reduced cell viability and increased oxidative stress and reactive oxygen species levels. Conclusions: Thrombopoietin alleviates doxorubicin-induced cardiomyocyte injury by reducing oxidative stress and apoptosis via the SIRT1/p38 MAPK pathway. However, its protective effects need to be further verified in animal tests.

Introduction: Aging and obesity have common symptoms, including glucose and lipid metabolism changes. Activation of sirtuin 1 and FOXO1 (Forkhead Box Protein O1) can positively affect metabolic disorders associated with aging and obesity. This research aimed to investigate 16 weeks of combined exercise on the plasma levels of sirtuin 1, FOXO1, and glucose homeostasis in obese elderly. Methods: 40 obese elderly men with an average age of 61.90 ± 2.84 were selected and randomly divided into two experimental and control groups. The participants trained three days a week (each session 90 minutes) for 16 weeks. 48 hours before and after exercise, anthropometric characteristics and plasma values of sirtuin 1, FOXO1, fasting blood sugar, insulin, HOMA-IR (Homeostatic Model Assessment for Insulin Resistance), and HOMA-B (Homeostasis Model Assessment of β-Cell) were taken from the samples and measured by ELISA method. Data analysis was done using SPSS 16 software, independent and dependent t-tests at a significance level of P˂ 0.05. Results: Levels of fasting blood sugar (P=0.04), and insulin (P=0.008) in the experimental group decreased significantly compared to the control group, while the serum levels of sirtuin1 (P=0.0001) and FOXO1 (P=0.0001) had a significant increase. Correlated t results in the experimental group showed a significant decrease in insulin, HOMA-IR, and HOMA-B (P = 0.001) and a significant increase in the serum levels of sirtuin1 (P = 0.0001) and FOXO1 (P = 0.0001) (P ˂ 0.05). Conclusion: Based on the results of this study, it seems that 16 weeks of combined training has a favorable effect on improving glucose homeostasis, increasing sirtuin 1 and FOXO1 levels in elderly obese men.

8-Prenylgenistein (8PG), a genistein derivative, is present in fermented soybeans (Glycine max), including cheonggukjang (CGJ), and exhibits osteoprotective, osteogenic, and antiadipogenic properties. However, the hepatoprotective effects of 8PG and its underlying molecular mechanisms remain largely unexplored. Here, we identified the high binding affinity of 8PG with AMP-activated protein kinase (AMPK) and sirtuin 1 (SIRT1), which acts as a potent AMPK activator that counteracts hepatic steatosis. Notably, 8PG exhibited better pharmacokinetics with greater absorption and higher plasma binding than the positive controls for the target proteins. Moreover, 8PG exerted non-carcinogenic activity in rats and significantly increased AMPK phosphorylation. Compound C, an AMPK inhibitor, did not antagonize 8PG-activated AMPK in HepG2 cells. 8PG significantly attenuated palmitate-induced lipid accumulation and enhanced phosphorylated AMPK and its downstream target, acetyl-CoA carboxylase. Further, 8PG activated nuclear SIRT1 at the protein level, which promoted fatty acid oxidation in palmitate-treated HepG2 cells. Overall, 8PG acts as a potent AMPK activator, further attenuating hepatic steatosis via the SIRT1-mediated pathway and providing new avenues for dietary interventions to treat metabolic dysfunction-associated steatotic liver disease (MASLD). [ABSTRACT FROM AUTHOR]

NAD+-dependent deacetylase sirtuin-1 (Sirt1) belongs to the sirtuins family, known to be longevity regulators, and exerts a key role in the prevention of vascular aging. By aging, the expression levels of Sirt1 decline with a severe impact on vascular function, such as the rise of endothelial dysfunction, which in turn promotes the development of cardiovascular diseases. In this context, the impact of Sirt1 activity in preventing endothelial senescence is particularly important. Given the key role of Sirt1 in counteracting endothelial senescence, great efforts have been made to deepen the knowledge about the intricate cross-talks and interactions of Sirt1 with other molecules, in order to set up possible strategies to boost Sirt1 activity to prevent or treat vascular aging. The aim of this review is to provide a proper background on the regulation and function of Sirt1 in the vascular endothelium and to discuss the recent advances regarding the therapeutic strategies of targeting Sirt1 to counteract vascular aging. [ABSTRACT FROM AUTHOR]

Objective: To explore whether thrombopoietin can exert a protective effect against doxorubicin-induced cardiotoxicity by modulating the sirtuin 1 (SIRT1) signaling pathway. Methods: H9c2 cell viability was determined by CCK-8 and cardiomyocyte apoptosis was detected by TUNEL assay. The protein expressions of SIRT1 and p38 MAPK were measured by Western blot. RT-qPCR was also used to determine S1RT1 mRNA expression. In addition, intracellular reactive oxygen species levels and antioxidant enzyme activities were evaluated. Results: Thrombopoietin treatment reversed doxorubicin-induced decline in H9c2 cell viability. It also increased SIRT1 and decreased p-p38 MAPK protein expressions. In addition, thrombopoietin significantly attenuated doxorubicin-induced apoptosis and oxidative stress, and enhanced antioxidant enzyme activities. However, silencing S1RT1 abrogated the protective effects of thrombopoietin, as evidenced by reduced cell viability and increased oxidative stress and reactive oxygen species levels. Conclusions: Thrombopoietin alleviates doxorubicin-induced cardiomyocyte injury by reducing oxidative stress and apoptosis via the SIRT1/p38 MAPK pathway. However, its protective effects need to be further verified in animal tests. [ABSTRACT FROM AUTHOR]

The number of infertile couples undergoing in vitro fertilisation (IVF) has increased significantly. The efficacy of this procedure is contingent upon a multitude of factors, including gamete quality. One factor influencing gamete quality is oxidative stress, which leads to telomere damage and accelerates cellular ageing. Identifying new biomarkers that can predict the success of assisted reproduction techniques is a current relevant area of research. In this review, we discuss the potential role of SIRT1, a protein known to protect against oxidative stress and telomeres, which are responsible for genome stability, as biomarkers of gamete quality and assisted reproduction technique outcomes. [ABSTRACT FROM AUTHOR]

Phosphate homeostasis is vital for many biological processes and disruptions in circulating levels can be detrimental. While the mechanisms behind FGF23 regulation have been regularly studied, the role of extracellular phosphate sensing and its impact on fibroblast growth factor 23 (FGF23) expression remains unclear. This study aimed to investigate the involvement of reactive oxygen species (ROS), silent information regulator 1 (SIRT1), and Hairy and Enhancer of Split-1 (HES1) in regulating FGF23 in FGF23 expressing MC3T3-E1 cells. MC3T3-E1 cells treated with β-glycerophosphate (BGP) resulted in increased Fgf23 expression. Inhibition of ROS formation by inhibition of NADPH oxidase, which is essential for ROS production, did not affect this response to BGP, suggesting ROS is not involved in this process. Moreover, treatment with tert-butyl hydroperoxide (TBHP), a ROS-inducing agent, did not increase Fgf23 expression. This suggests that ROS machinery is not involved in FGF23 stimulation as previously suggested. Nonetheless, inhibition of SIRT1 using Ex527 eliminated the Fgf23 response to BGP, indicating its involvement in FGF23 regulation after BGP treatment. Indeed, activation of SIRT1 using SRT1720 increased Fgf23 expression. Moreover, transcription factor Hes1 was upregulated by BGP treatment, which was diminished when cells were treated with Ex527 implying it is also regulated through SIRT1. These findings suggest the existence of an upstream SIRT1-HES1 axis in the regulation of FGF23 by phosphate, though we were unable to find a role for ROS in this process. Further research should provide insights into phosphate homeostasis and potential therapeutic targets for phosphate-related disorders. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the effect of nicotinamide (Nam) on diabetic kidney disease (DKD) in mice and explore its mechanism. Methods: Thirty DBA/2 J mice were randomly assigned to three groups. After 8 weeks of hyperglycemia induced by streptozocin (STZ), Nam and saline were administrated to STZ + Nam and STZ + NS mice, respectively, for 8 weeks. Non-diabetic mice (NDM) were used as control group. Twenty In2−/− Akita mice were randomly divided into two groups. After 8 weeks of hyperglycemia, Nam and saline were administered to Akita + Nam and Akita + NS mice, respectively, for 6 weeks. Wild-type littermates were used as control group. Markers of renal injury were analyzed, and the molecular mechanisms were explored in human proximal tubular HK2 cells. Results: Urinary albumin-to-creatinine ratio (UACR) and kidney injury molecule 1 (KIM-1) decreased in the STZ + Nam and Akita + Nam groups. Pathological analysis showed that Nam improved the structure of glomerular basement membrane, ameliorated glomerular sclerosis, and decreased the accumulation of extracellular matrix and collagen. Compared to the diabetic control group, renal fibrosis, inflammation, and oxidative stress were reduced in the Nam-treated mice. The expression of sirtuin 1 (Sirt1) in human proximal tubular HK2 cells was inhibited by high glucose and Nam treatment enhanced its expression. However, in HK2 cells with Sirt1 knockdown, the protective effect of Nam was abolished, indicating that the beneficial effect of Nam was partially dependent on Sirt1. Conclusions: Nam has a renoprotective effect against renal injury caused by hyperglycemia and may be a potential target for the treatment of DKD. [ABSTRACT FROM AUTHOR]

The time for diabetic nephropathy (DN) to progress from mild to severe is long. Thus, methods to continuously repress DN are required to exert long-lasting effects mediated through epigenetic regulation. In this study, we demonstrated the ability of nicotinamide adenine dinucleotide (NAD) and its metabolites to reduce albuminuria through Sirt1- or Nampt-dependent epigenetic regulation. We previously reported that proximal tubular Sirt1 was lowered before glomerular Sirt1. Repressed glomerular Sirt1 was found to epigenetically elevate Claudin-1. In addition, we reported that proximal tubular Nampt deficiency epigenetically augmented TIMP-1 levels in Sirt6-mediated pathways, leading to type-IV collagen deposition and diabetic fibrosis. Altogether, we propose that the Sirt1/Claudin-1 axis may be crucial in the onset of albuminuria at the early stages of DN and that the Nampt/Sirt6/TIMP-1 axis promotes diabetic fibrosis in the middle to late stages of DN. Finally, administration of NMN, an NAD precursor, epigenetically potentiates the regression of the onset of DN to maintain Sirt1 and repress Claudin-1 in podocytes, suggesting the potential use of NAD metabolites as epigenetic medications for DN. [ABSTRACT FROM AUTHOR]

Sirtuin 1 (SIRT1) inhibits growth hormone (GH) intracellular signaling for the insulin-like growth factor 1 (IGF-1) synthesis via the janus kinase (JAK)/signal transducer and activator of transcription proteins (STATs) pathway. The aim of this study was to compare SIRT1 concentrations in children with GH deficiency (GHD) and so-called idiopathic short stature (ISS, non-GH deficient), in order to determine the possible impact of changes in serum SIRT1 concentrations on the GH-IGF-1 axis. The study group included 100 short-stature children: 38 with GHD and 62 with ISS (maxGH in two stimulation tests <10 and ≥10 ng/mL, respectively). The control group consisted of 47 healthy, normal-height children. For each child, the concentrations of SIRT1, IGF-1 and insulin-like growth factor-binding protein 3 (IGFBP-3) were determined and the IGF-1/IGFBP-3 molar ratio was calculated. The level of SIRT1 was significantly higher in both groups of short children than in the controls (p < 0.0001), but there were no differences between GHD and ISS (mean ± SD: 0.89 ± 0.45 for ISS; 1.24 ± 0, 86 for GHD; and 0.29 ± 0.21 for controls). A significant negative correlation was found between SIRT1 and height standard deviation score (SDS), IGF-1 and IGF-1/IGFBP-3, but not between SIRT1 and maxGH. Elevated SIRT1 levels may serve as one of the mechanisms through which the secretion of IGF-1 is reduced in children with short stature; however, further research is required to confirm this issue. [ABSTRACT FROM AUTHOR]

Hyperglycemia affects approximately 16.7% of pregnancies worldwide, with gestational diabetes mellitus (GDM) accounting for nearly 84% of these cases. GDM, characterized by glucose intolerance during pregnancy, presents significant health risks. Rosmarinus officinalis (RO) and Centella asiatica (CA) are known for their antidiabetic and antioxidant properties, including the ability to enhance insulin secretion and inhibit phosphoenolpyruvate carboxykinase (PEPCK) expression in the gluconeogenesis pathway. This study aims to assess the impact of a nanoemulsion of RO and CA combination (ROCA) on heart rate, superoxide dismutase (SOD), nuclear factor erythroid 2-related factor 2a (Nrf2a), sirtuin 1 (SIRT-1), and tyrosine hydroxylase (TH) expression in zebrafish larvae model of GDM. GDM was induced by exposure of zebrafish embryo to a 3% glucose solution in an embryonic medium. The GDM phenotype was confirmed by elevated PEPCK expression as a hyperglycemia marker. GDM zebrafish was administered RO-CA nanoemulsion at concentrations of 2.5, 5, and 10 μg/mL.from 2 hpf to 72 hpf. Heart rate was monitored using stereoscopic imaging connected to a camera, while expression levels of PEPCK, Nrf2a, SOD, SIRT-1, and TH were quantified using reverse transcriptase polymerase chain reaction (RT-PCR). Results revealed a significant decrease in PEPCK expression in the treatment groups compared to the glucose untreated group. Notably, the nanoemulsion maintained heart rate frequency and upregulated Nrf2a, SOD, SIRT-1, and TH expression, particularly at a concentration of 2.5 μg/mL. Overall, these findings suggest that the RO-CA nanoemulsion exhibits enhanced antioxidant activity and holds promise as a potential cardioprotective agent in GDM. [ABSTRACT FROM AUTHOR]

mTORC1 is the key rheostat controlling the cellular metabolic state. Of the various inputs to mTORC1, the most potent effector of intracellular nutrient status is amino acid supply. Despite an established role for MAP4K3 in promoting mTORC1 activation in the presence of amino acids, the signaling pathway by which MAP4K3 controls mTORC1 activation remains unknown. Here, we examined the process of MAP4K3 regulation of mTORC1 and found that MAP4K3 represses the LKB1-AMPK pathway to achieve robust mTORC1 activation. When we sought the regulatory link between MAP4K3 and LKB1 inhibition, we discovered that MAP4K3 physically interacts with the master nutrient regulatory factor sirtuin-1 (SIRT1) and phosphorylates SIRT1 to repress LKB1 activation. Our results reveal the existence of a novel signaling pathway linking amino acid satiety with MAP4K3-dependent suppression of SIRT1 to inactivate the repressive LKB1-AMPK pathway and thereby potently activate the mTORC1 complex to dictate the metabolic disposition of the cell.

The incidence of atrial fibrillation (AF) increases with age and is particularly high in individuals with diabetes. Sodium-glucose cotransporter-2 inhibitors (SGLT2i), such as dapagliflozin, show promise in treating heart failure (HF) and reducing the risk of AF. Sirtuin 1 (SIRT1), a key enzyme in metabolic regulation, may be influenced by SGLT2i and play a role in the development of AF. This study investigates the relationship between dapagliflozin therapy and atrial tachyarrhythmia in diabetic cardiomyopathy, with a focus on the role of SIRT1. A streptozotocin (STZ)-induced diabetes mellitus (DM) rat model was used to assess AF across four groups: sham, STZ, STZ with dapagliflozin, and STZ with dapagliflozin + sirtinol (a SIRT1 inhibitor). Additionally, HL-1 cardiomyocytes were cultured under high glucose (HG) conditions and treated with dapagliflozin, with or without sirtinol. In the rat model, dapagliflozin improved atrial fibrosis and reduced AF inducibility and duration—effects that were partially reversed by sirtinol. These findings suggest that dapagliflozin may alleviate cardiac fibrosis and atrial arrhythmia by modulating SIRT1. In HL-1 cells under HG conditions, dapagliflozin reduced apoptosis, restored autophagy and mitophagy, and improved calcium channel activity. However, sirtinol negated these protective effects. Dapagliflozin helped normalize autophagy, mitophagy, and calcium handling, while sirtinol diminished its protective effects, highlighting the key role of SIRT1 in regulating calcium handling under HG conditions. Overall, SIRT1 plays a protective role in diabetic cardiomyopathy by reducing apoptosis, regulating autophagy and mitophagy, and modulating calcium channel activity. Dapagliflozin reduces AF duration and inducibility in the STZ model, likely through SIRT1 upregulation and calcium channel modulation.

Background: Hypertrophy of the ligamentum flavum (HLF) is a common contributor to spinal stenosis which results in significant neurological impairments. Circular RNA (circRNA) circ_0003609 has been linked to HLF; however, the exact mechanism by which it causes this disease is unclear. Methods: Circ_0003609 expressions were regulated in HLF cells by overexpression vectors and RNA interference. Cell proliferation and fibrosis-related gene expression were checked by the Cell Counting Kit-8 (CCK-8) assay and western blotting. CircBank's prediction of the association between miR-155 and circ_0003609 was supported by a dual-luciferase reporter experiment. The function of the miR-155/sirtuin 1 (SIRT1) axis in controlling HLF fibrosis was further examined. Results: Overexpression of circ_0003609 suppressed HLF cell propagation and fibrosis compared to its silencing. It was found that circ_0003609 served as the sponge for miR-155 and that the circ_0003609/miR-155 axis controlled the fibrosis of HLF cells. It was found that circ_0003609 acted as a sponge for miR-155, regulating the fibrosis of HLF cells. Further, miR-155 targets SIRT1, and the miR-155/SIRT1 axis promotes HLF cell fibrosis. Conclusion: Circ_0003609 ameliorates hypertrophied ligamentum flavum (LF) by modulating the miR-155/SIRT1 axis, indicating a potential treatment approach for HLF. [ABSTRACT FROM AUTHOR]

Hepatocellular carcinoma (HCC) remains a major global health problem with high incidence and mortality. Diagnosis of HCC at late stages and tumour heterogeneity in patients with different genetic profiles are known factors that complicate the disease treatment. HCC therapy becomes even more challenging in patients with drug resistance such as resistance to sorafenib, which is a common drug used in HCC patients. Sorafenib resistance can further aggravate HCC by regulating various oncogenic pathways such as autophagy and nuclear factor-kappa Beta (NF-ĸβ) signalling. Sirtuin 1 (SIRT1), is a nicotinamide adenosine dinucleotide (NAD)-dependent histone deacetylases that regulates various metabolic and oncogenic events such as cell survival, apoptosis, autophagy, tumourigenesis, metastasis and drug resistance in various cancers, but its role in HCC, particularly in sorafenib resistance is underexplored. In this study, we generated sorafenib-resistant HepG2 and Huh-7 liver cancer cell models to investigate the role of SIRT1 and its effect on autophagy and nuclear factor-kappa Beta (NF-ĸβ) signalling pathways. Western blot analysis showed increased SIRT1, altered autophagy pathway and activated NF-ĸβ signalling in sorafenib-resistant cells. SIRT1-silenced HCC cells demonstrated down-regulated autophagy in both parental and chemoresistant cells. This may occur through the deacetylation of key autophagy molecules such as FOXO3, beclin 1, ATGs and LC3 by SIRT1, highlighting the role of SIRT1 in autophagy induction. Silencing of SIRT1 also resulted in activated NF-ĸβ signalling. This is because SIRT1 failed to deacetylate p65 subunit of NF-κB, translocate the NF-κB from nucleus to cytoplasm, and suppress NF-κB activity due to the silencing. Hence, the NF-κB transcriptional activity was restored. These findings summarize the role of SIRT1 in autophagy/NF-ĸβ regulatory axis, with a similar trend observed in both parental and sorafenib-resistant cells. The present work promotes a better understanding of the role of SIRT1 in autophagy and NF-ĸβ signalling in HCC and sorafenib-resistant HCC. As some key proteins in these pathways are potential therapeutic targets, a better understanding of SIRT1/autophagy/NF-ĸβ axis could further improve the therapeutic strategies against HCC. [ABSTRACT FROM AUTHOR]

Introduction: Methamphetamine (METH) is an addictive psychostimulant with deleterious effects on the central nervous system. Chronic use of METH in high doses impairs cognition, attention and executive functions, but the underlying mechanisms are still unclear. Sirtuin 1 (SIRT1) is a post-translational regulator that is downregulated following METH neurotoxicity. Melatonin is a neuroprotective hormone that enhances mitochondrial metabolism. Here, we evaluated the effect of melatonin on METH-induced attention deficits disorder and the involvement of the miR-181/SIRT1 axis in melatonin neuroprotection. Methods and results: METH at a dose of 5 mg/kg was injected for 21 consecutive days. The animals were assigned to receive either melatonin or the vehicle after METH injections. Attention levels were evaluated with abject-based attention test. In the prefrontal cortex, the expression levels of miR-181a-5p, SIRT1, p53 and CCAR2, as well as the mtDNA copy numbers were evaluated using qRT-PCR and western blotting. The outcomes revealed that melatonin treatment following METH injections improved METH-induced attention deficits. METH toxicity can be associated with changes in the miR-181/SIRT1 axis, elevated levels of p53 and COXII, and decreased levels of mtDNA in the prefrontal cortex of adult rats. Interestingly, administration of melatonin can improve the expression of these molecules and reduces the toxic effects of METH. Conclusion: Melatonin ameliorated the neurotoxicity of METH in the prefrontal cortex and the miR-181/SIRT1 axis is involve in the protective effects of melatonin. However, melatonin can be potentially administrated to improve attention impairment in METH use disorders. [ABSTRACT FROM AUTHOR]

Purpose: Considering inhibition of pre-adipocyte cells differentiation in adipose tissue fibrosis, we aimed to explore whether Sirt1 and Hif-1α in pre-adipocytes have a significant effect on fibrotic gene expression. Methods: 3T3-L1 pre-adipocytes were transfected with SIRT1-specific siRNA, confirmed by real-time polymerase chain reaction (RT-PCR) and western blotting. Additionally, cells were treated with varying concentrations of resveratrol and sirtinol as the activator and inhibitor of Sirt1, respectively. Involvement of Hif-1α was evaluated by treatment with echinomycin. Subsequently, we assessed the gene and protein expressions related to fibrosis in the extracellular matrix of adipose tissue, including collagen VI (Col VI), lysyl oxidase (Lox), matrix metalloproteinase-2 (Mmp-2), Mmp-9, and osteopontin (Opn) in pre-adipocytes through RT-PCR and western blot. Results: The current study demonstrated that Sirt1 knockdown and reduced enzyme activity significantly increased the expression of Col VI, Lox, Mmp-2, Mmp-9, and Opn genes in the treated 3T3-L1 cells compared to the control group. Interestingly, resveratrol significantly decreased the gene expression related to the fibrosis pathway. Inhibition of Hif-1α by echinomycin led to a significant reduction in Col VI, Mmp-2, and Mmp-9 gene expression in the treated group compared to the control. Conclusion: This study highlights that down-regulation of Sirt1 might be a predisposing factor in the emergence of adipose tissue fibrosis by enhancing the expression of extracellular matrix (ECM) components. Activation of Sirt1, similar to suppressing of Hif-1α in pre-adipocytes may be a beneficial approach for attenuating fibrotic gene expression. [ABSTRACT FROM AUTHOR]

Diabetic cardiomyopathy (DCM) is one of the most serious cardiovascular complications in diabetic patients, and it is also the main cause of increased mortality in diabetic patients, which has become a major global public health problem. As an important intracellular regulatory protein in body, sirtuin 1 (SIRT1) plays an important role in many biological processes, including reducing oxidative stress in cardiomyocytes, maintaining Ca2+ homeostasis in myocardial mitochondria, reducing myocardial endoplasmic reticulum stress, improving myocardial mitochondrial dysfunction, and inhibiting the activation of renin-angiotensin-aldosterone system. SIRT1 may be a potential therapeutic target for DCM. Further research targeting SIRT1 can provide a new theoretical basis for the clinical treatment of DCM. This article reviews the specific role of SIRT1 in the pathogenesis and treatment strategies of DCM. [ABSTRACT FROM AUTHOR]

Summary: Atypical teratoid/rhabdoid tumors (ATRTs) are highly malignant embryonal tumors of the central nervous system with a dismal prognosis. Using a newly developed and validated patient-derived ATRT culture and xenograft model, alongside a panel of primary ATRT models, we found that ATRTs are selectively sensitive to the nucleoside analog gemcitabine. Gene expression and protein analyses indicate that gemcitabine treatment causes the degradation of sirtuin 1 (SIRT1), resulting in cell death through activation of nuclear factor κB (NF-κB) and p53. Furthermore, we discovered that gemcitabine-induced loss of SIRT1 results in a nucleus-to-cytoplasm translocation of the sonic hedgehog (SHH) signaling activator GLI2, explaining the observed additional gemcitabine sensitivity in SHH-subtype ATRT. Treatment of ATRT xenograft-bearing mice with gemcitabine resulted in a >30% increase in median survival and yielded long-term survivors in two independent patient-derived xenograft models. These findings demonstrate that ATRTs are highly sensitive to gemcitabine treatment and may form part of a future multimodal treatment strategy for ATRTs.

Dermal fibroblasts play a crucial role in skin structure and function by producing hyaluronic acid. Piceatannol (PIC), a polyphenol abundant in passion fruit seeds, has been reported to activate sirtuin 1 (SIRT1). Clinical trials have demonstrated that PIC intake improves skin moisture and maintains skin elasticity, yet the underlying mechanism remains unclear. This study aimed to investigate the effects of PIC on hyaluronic acid biosynthesis and the involvement of SIRT1 in this process. Human dermal fibroblast Hs68 cells were stimulated with PIC, and the expression levels of HAS2 and HYAL2, key enzymes in hyaluronic acid biosynthesis, as well as SIRT1 expression, were assessed using quantitative real-time PCR. Additionally, the role of SIRT1 in the hyaluronic acid biosynthesis pathway during PIC stimulation was examined using a SIRT1 inhibitor. The results demonstrated that PIC increased HAS2 expression while decreasing HYAL2 expression in human dermal fibroblasts. Furthermore, PIC enhanced SIRT1 expression, and pre-treatment with a SIRT1 inhibitor mitigated PIC-induced upregulation of HAS2, suggesting that PIC promotes hyaluronic acid synthesis by inducing SIRT1. These findings suggest that PIC could serve as a beneficial food ingredient, enhancing skin structure and function by promoting hyaluronic acid biosynthesis via SIRT1 induction.

Background: Lipid accumulation and redox imbalance, resulting from dysregulation of hepatic fatty acids oxidation, contribute to the development of steatohepatitis and insulin resistance. Recently, dysregulated RNA N6-methyladenosine (m6A) methylation modification has been found involving fatty liver. However, the role of methyltransferase-like 14 (METTL14), the core component of m6A methylation, in the development of steatohepatitis is unknown. Herein, we aimed to explore the role of METTL14 on steatohepatitis and insulin resistance in mice with metabolic dysfunction-associated steatotic liver disease (MASLD). Methods: The liver tissues of mice and patients with MASLD were collected to detect the expression of METTL14. METTL14 overexpression and METTL14 silence were used to investigate the effect of METTL14 on lipid metabolism disorder in vivo and in vitro. Knockout of METTL14 in primary hepatocytes was used to investigate the role of Sirtuin 1 (SIRT1) on lipid accumulation induced by METTL14. Results: METTL14 was dramatically up-regulated in the livers of db/db mice, high-fat diet (HFD)-fed mice, and patients with MASLD. METTL14 overexpression exacerbated MASLD and promoted lipid metabolism disorder and insulin resistance in mice. Conversely, METTL14 knockout ameliorated lipid deposition and insulin resistance in HFD-fed mice. Furthermore, METTL14 overexpression facilitated lipid accumulation, while METTL14 knockout reduced lipid accumulation in HepG2 cells and primary hepatocytes. In addition, METTL14 lost up-regulated SIRT1 expression in hepatocytes. SIRT1 deficiency abrogated the ameliorating effects of METTL14 downregulation in MASLD mice. Conclusions: These findings suggest that dysfunction of the METTL14-SIRT1 pathway might promote hepatic steatosis and insulin resistance.

Histone acetylation levels are reduced during mitosis. To study the mitotic regulation of H3K9ac, we used an array of inhibitors targeting specific histone deacetylases. We evaluated the involvement of the targeted enzymes in regulating H3K9ac during all mitotic stages by immunofluorescence and immunoblots. We identified HDAC2, HDAC3, and SIRT1 as modulators of H3K9ac mitotic levels. HDAC2 inhibition increased H3K9ac levels in prophase, whereas HDAC3 or SIRT1 inhibition increased H3K9ac levels in metaphase. Next, we performed ChIP-seq on mitotic-arrested cells following targeted inhibition of these histone deacetylases. We found that both HDAC2 and HDAC3 have a similar impact on H3K9ac, and inhibiting either of these two HDACs substantially increases the levels of this histone acetylation in promoters, enhancers, and insulators. Altogether, our results support a model in which H3K9 deacetylation is a stepwise process-at prophase, HDAC2 modulates most transcription-associated H3K9ac-marked loci, and at metaphase, HDAC3 maintains the reduced acetylation, whereas SIRT1 potentially regulates H3K9ac by impacting HAT activity.

Objective To investigate the effect of nicotinamide adenine dinucleotide-dependent deacetylase 1 (Sirt1) on high glucose-induced exosome release from podocytes. Methods Immortalized mouse podocytes MPC5 were divided into six groups: normal glucose group (5.5 mmol/L glucose, group A), high mannitol group (5.5 mmol/L glucose+24.5 mmol/L mannitol, group B), high glucose group (30.0 mmol/L glucose, group C), high glucose+Sirt1-overexpressed lentivirus transfection group (Sirt1-overexpressed lentivirus transfection+30.0 mmol/L glucose, group D), high glucose+negative lentivirus transfection group (negative lentivirus transfection+30.0 mmol/L glucose, group E), and high glucose+exosome secretion inhibitor group (GW4869+30.0 mmol/L glucose, group F). Western blot was used to analyze the expression levels of Nephrin, Podocin, Sirt1, CD63, CD81, and Alix in each group. Real-time quantitative polymerase chain reaction was used to analyze the expression level of Sirt1 mRNA in D and E group. The morphology of podocyte exosomes was observed by a transmission electron microscope. The particle size and concentration of exosomes were determined by nanoparticle tracking analysis. Results The results of RT-qPCR showed that the relative expression of Sirt1 mRNA was significantly increased in group D compared with that in group E (t=14.580,P0.05). Conclusion Loss of Sirt1 in high glucose-treated podocytes promotes exosome secretion and podocyte injury.

Background: Renal interstitial fibrosis is the pathophysiological basis of type 2 diabetes mellitus (T2DM). Exercise appears to improve kidney interstitial fibrosis in T2DM, in which silent information regulator factor 2-related enzyme 1 (Sirt1) is a critical regulator. However, the role of Sirt1 in mediating exercise on renal tissue as well as its mechanism remains unknown. Methods: T2DM mouse models were created using a high-fat diet mixed with streptozotocin, followed by 8 weeks of treadmill exercise and niacinamide (Sirt1 inhibitor) intervention. Kits for detecting biochemical indices of renal function were used. The pathological appearance and severity of renal tissue were examined using hematoxylin and eosin, Masson and immunohistochemical staining. The mRNA and protein expression of relevant signaling pathway factors were determined to use real-time reverse transcriptase-polymerase chain reaction and western blotting. Results: T2DM can promote renal interstitial fibrosis, increase kidney index, serum creatinine, blood urea nitrogen and 24 h urinary total protein and cause pathological changes in renal tissue and affect renal function. After 8 weeks of exercise intervention, the biochemical indicators in the kidney of T2DM mice were decreased, Sirt1 expression was increased, the expression of TGF-β1, Smad3, collagen type I (COL1) and collagen type III (COL3) were decreased, and the renal interstitial fibrosis, renal tissue structural lesions and renal function were improved. However, after the nicotinamide intervention, renal interstitial fibrosis of T2DM mice was aggravated, and the improvement effect of exercise on renal interstitial fibrosis of T2DM mice was abolished. Conclusion: The upregulation of Sirt1 expression by exercise can inhibit the transforming growth factor β1/Smad3 pathway, thereby inhibiting the expression and deposition of COL1 and COL3 in renal interstitium, thereby improving renal interstitial fibrosis in T2DM.

Aging is a natural process that is also influenced by some factors like the food someone eats, lifestyle decisions, and impacts on general health. Despite the recognized role of nutrition in modulating the molecular and cellular mechanisms underlying aging, there is a lack of comprehensive exploration into potential interventions that can effectively mitigate these effects. In this study, we investigated the potential anti-aging properties of vitamin D by examining its interactions with key molecular targets involved in aging-related pathways. By using molecular docking and dynamics techniques, we evaluate the interactions and stability of vitamins D2 and D3 with key proteins involved in aging pathways, such as SIRT1, mTOR, AMPK, Klotho, AhR, and MAPK. Our results reveal promising binding affinities between vitamin D and SIRT1 forms, with energy values of −48.33 kJ/mol and −45.94 kJ/mol for vitamins D2 and D3, respectively, in aqueous environments. Moreover, molecular dynamics simulations revealed that the vitamin D3–SIRT1 complex exhibited greater stability compared with the vitamin D2–SIRT1 complex. The study calculated the solvation free energy to compare the solubility of vitamins D2 and D3 in water and various organic solvents. Despite their strong interactions with water, both vitamins exhibited low solubility, primarily due to the high energy cost associated with cavity formation in the aqueous environment. Compared with other solvents, water demonstrated particularly low solubility for both vitamins. This suggested that vitamins D2 and D3 preferred binding to aging receptors over dissolving in bulk aqueous environments, supporting their strong therapeutic interactions with these receptors. These findings shed light on the molecular mechanisms underlying vitamin D’s potential anti-aging effects and lay the groundwork for developing nutraceuticals targeting aging and associated diseases. Understanding these mechanisms holds promise for future interventions aimed at promoting healthy aging and enhancing overall well-being.

Most deaths from the COVID-19 pandemic are due to acute respiratory distress syndrome (ARDS)-related respiratory failure. Cytokine storms and oxidative stress are the major players in ARDS development during respiratory virus infections. However, it is still unknown how oxidative stress is regulated by viral and host factors in response to SARS-CoV-2 infection. Here, we found that activation of NRF2/HMOX1 significantly suppressed SARS-CoV-2 replication in multiple cell types by producing the metabolite biliverdin, whereas SARS-CoV-2 impaired the NRF2/HMOX1 axis through the action of the nonstructural viral protein NSP14. Mechanistically, NSP14 interacts with the catalytic domain of the NAD-dependent deacetylase Sirtuin 1 (SIRT1) and inhibits its ability to activate the NRF2/HMOX1 pathway. Furthermore, both genetic and pharmaceutical evidence corroborated the novel antiviral activity of SIRT1 against SARS-CoV-2. Therefore, our findings reveal a novel mechanism by which SARS-CoV-2 dysregulates the host antioxidant defense system and emphasize the vital role played by the SIRT1/NRF2 axis in host defense against SARS-CoV-2.

Introduction: Sirtuin 1 (SIRT1) is known to be involved in sensing cellular energy levels and regulating energy metabolism. This study aimed to evaluate fasting serum SIRT1 levels in healthy children, and to analyse the influence of age, sex, puberty, body weight, height, and diet on its concentration. Methods: 47 healthy children aged 4-14 with weight and height within normal range and no chronic disease were included into the study. Fasting serum SIRT1 concentrations were estimated by Enzyme Linked Immunosorbent Assay (ELISA). Results: Results showed that serum SIRT1 concentrations in healthy children did not differ with respect to sex, age, height, weight and puberty. Whereas, it appeared that a higher frequency of fruits, vegetables and dairy products consumption was associated with an increase in serum SIRT1 levels. Discussion: Studying SIRT1 in the context of children’s health may have implications for a broader understanding of growth processes, pubertal development, metabolic disorders and nutrition. [ABSTRACT FROM AUTHOR]

Sepsis, a leading cause of death worldwide, is a harmful inflammatory condition that is primarily caused by an endotoxin released by Gram-negative bacteria. Effective targeted therapeutic strategies for sepsis are lacking. In this study, using an in vitro and in vivo mouse model, we demonstrated that CM1, a derivative of the natural polyphenol chrysin, exerts an anti-inflammatory effect by inducing the expression of the ubiquitin-editing protein TNFAIP3 and the NAD-dependent deacetylase sirtuin 1 (SIRT1). Interestingly, CM1 attenuated the Toll-like receptor 4 (TLR4)-induced production of inflammatory cytokines by inhibiting the extracellular-signal-regulated kinase (ERK)/MAPK and nuclear factor kappa B (NF-κB) signalling pathways. In addition, CM1 induced the expression of TNFAIP3 and SIRT1 on TLR4-stimulated primary macrophages; however, the anti-inflammatory effect of CM1 was abolished by the siRNA-mediated silencing of TNFAPI3 or by the genetic or pharmacologic inhibition of SIRT1. Importantly, intravenous administration of CM1 resulted in decreased susceptibility to endotoxin-induced sepsis, thereby attenuating the production of pro-inflammatory cytokines and neutrophil infiltration into the lung compared to control mice. Collectively, these findings demonstrate that CM1 has therapeutic potential for diverse inflammatory diseases, including sepsis. [ABSTRACT FROM AUTHOR]

Background: When the skin is damaged and its barrier function is disrupted, the proliferation and migration of epidermal keratinocytes are vital for repairing the damaged area. The Schumann resonance at 7.8 Hz has been reported to protect rat cardiomyocytes against oxidative stress and inhibit the proliferation of B16 mouse melanoma cells. However, its effect on the skin is unknown. Aims: In this study, we applied 7.8‐Hz electromagnetic waves to normal human epidermal keratinocytes (NHEKs) and investigated its effects on cell proliferation and migration, β‐defensin (DEFB1) and sirtuin 1 (SIRT1) expression. Methods: We performed cell proliferation assay, cell migrationassay and gene expression analysis of DEFB1 and SIRT1. Results: We found that the application of 7.8‐Hz electromagnetic waves caused a 2.8‐fold increase in NHEK proliferation, enhanced cell migration, and increased the expression of DEFB1 and SIRT1 by 2.4‐fold and 4.9‐fold, respectively. Conclusions: These results suggest that the application of 7.8‐Hz electromagnetic waves may contribute to improving the skin barrier function and skin ulcer. [ABSTRACT FROM AUTHOR]

Background: Menaquinone-4(MK-4), the isoform of vitamin K2 in the brain, exerts neuroprotective effects against a variety of central nervous system disorders. This study aimed to demonstrate the anti-ferroptosis effects of MK-4 in neurons after SAH. Methods: A subarachnoid hemorrhage (SAH) model was prepared by endovascular perforation in mice. In vitro hemoglobin stimulation of primary cortical neurons mimicked SAH. MK-4, Brequinar (BQR, DHODH inhibitor), and Selisistat (SEL, SIRT1 inhibitor) were administered, respectively. Subsequently, WB, immunofluorescence was used to determine protein expression and localization, and transmission electron microscopy was used to observe neuronal mitochondrial structure while other indicators of ferroptosis were measured. Results: MK-4 treatment significantly upregulated the protein levels of DHODH; decreased GSH, PTGS2, NOX1, ROS, and restored mitochondrial membrane potential. Meanwhile, MK-4 upregulated the expression of SIRT1 and promoted its entry into the nucleus. BQR or SEL partially abolished the protective effect of MK-4 on, neurologic function, and ferroptosis. Conclusions: Taken together, our results suggest that MK-4 attenuates ferroptosis after SAH by upregulating DHODH through the activation of SIRT1. SAH: subarachnoid hemorrhage; ROS: reactive oxygen species; MK-4: menaquinone-4; DHODH: dihydroorotate dehydrogenase; SLC7A11: solute carrier family 7 member 11; GPX4: glutathione peroxidase-4; SIRT1: sirtuin 1; CoQ: Coenzyme Q; MDA: malondialdehyde; PLOOH: phospholipid hydroperoxides. [Display omitted] • Menaquinone-4 improves neurologic function and attenuates ferroptosis after SAH. • Menaquinone-4 attenuates ferroptosis after SAH by upregulating DHODH. • Activation of SIRT1 is a potential mechanism for Menaquinone-4 upregulation of DHODH. • Vitamin K2 levels in cerebrospinal fluid of SAH patients was significantly reduced. [ABSTRACT FROM AUTHOR]

Background: Biological aging is a physiological process that can be altered by various factors. The presence of a chronic metabolic disease can accelerate aging and increase the risk of further chronic diseases. The aim of the study was to determine whether the presence of metabolic syndrome (MetS) affects levels of markers that are associated with, among other things, aging. Material and Methods: A total of 169 subjects (58 with MetS, and 111 without metabolic syndrome, i.e., non-MetS) participated in the study. Levels of telomerase, GDF11/15, sirtuin 1, follistatin, NLRP3, AGEs, klotho, DNA/RNA damage, NAD+, vitamin D, and blood lipids were assessed from blood samples using specific enzyme-linked immunosorbent assay (ELISA) kits. Results: Telomerase (p < 0.01), DNA/RNA damage (p < 0.006) and GDF15 (p < 0.02) were higher in MetS group compared to non-MetS group. Only vitamin D levels were higher in the non-MetS group (p < 0.0002). Differences between MetS and non-MetS persons were also detected in groups divided according to age: in under 35-year-olds and those aged 35–50 years. Conclusions: Our results show that people with MetS compared to those without MetS have higher levels of some of the measured markers of biological aging. Thus, the presence of MetS may accelerate biological aging, which may be associated with an increased risk of chronic comorbidities that accompany MetS (cardiovascular, inflammatory, autoimmune, neurodegenerative, metabolic, or cancer diseases) and risk of premature death from all causes. [ABSTRACT FROM AUTHOR]

Introduction. During sepsis, the kidney is one of the most vulnerable organs. Sepsis-associated acute kidney injury (S-AKI) is hallmarked by renal inflammation, apoptosis, and oxidative injury. Ginsenoside Rg1 (Rg1) is a natural product that possesses abundant pharmacological actions and protects against many sepsis-related diseases. Nevertheless, its role and related mechanism in S-AKI remain to be determined. Materials and methods. S-AKI was induced using lipopolysaccharide (LPS, 10 mg/kg) via a single intraperitoneal injection. Rg1 (200 mg/kg) was intraperitoneally administered for 3 consecutive days before LPS treatment. For histopathological examination, murine kidney tissues were stained with hematoxylin and eosin. Tubular injury score was calculated to evaluate kidney injury. Serum creatinine and BUN levels were measured for assessing renal dysfunction. The levels and activities of oxidative stress markers (MDA, 4-HNE, PC, GSH, SOD, and CAT) in renal tissue were measured by corresponding kits. Renal cell apoptosis was detected by TUNEL staining. The protein levels of apoptosis-related markers (Bcl-2, Bax, and Cleaved caspase-3), proinflammatory factors, SIRT1, IκBα, p-NF-κB p65, and NF-κB p65 in kidneys were determined using western blotting. Immunofluorescence staining was employed to assess p-NF-κB p65 expression in renal tissues. Results. LPS-induced injury of kidneys and renal dysfunction in mice were ameliorated by Rg1. Rg1 also impeded LPS-evoked renal cell apoptosis in kidneys. Moreover, Rg1 attenuated LPS-triggered inflammation and oxidative stress in kidneys by inhibiting proinflammatory cytokine release, enhancing antioxidant levels and activities, and reducing lipid peroxidation. However, all these protective effects of Rg1 in LPS-induced AKI mice were reversed by EX527, an inhibitor of sirtuin 1 (SIRT1). Mechanistically, Rg1 upregulated SIRT1 protein expression, increased SIRT1 activity, and inactivated NF-κB signaling in the kidney of LPS-induced AKI mice, which was also reversed by EX527. Conclusions. Rg1 ameliorates LPS-induced kidney injury and suppresses renal inflammation, apoptosis, and oxidative stress in mice via regulating the SIRT1/NF-κB signaling. [ABSTRACT FROM AUTHOR]

Doxorubicin (DOX) is a widely used antineoplastic drug, but its clinical use is limited by significant toxicities, such as hepatotoxicity. In this study, we evaluated the effects of β‐lapachone (β‐LAP), a natural quinone‐containing compound, in a mouse model of DOX‐induced hepatotoxicity. β‐LAP was orally administered at 1.25, 2.5, and 5 mg/kg for 4 days, and a single dose of DOX (20 mg/kg) was injected intraperitoneally on the second day. Histopathological changes, liver function markers, antioxidant and inflammatory markers were assessed. β‐LAP ameliorated liver injury and liver function markers evoked by DOX. β‐LAP also downregulated the mRNA expression of nuclear factor‐kB‐corresponding genes including interleukin‐6, interleukin‐1β, and tumor necrosis factor‐α. Moreover, β‐LAP increased the nuclear factor erythroid 2‐related factor 2 target genes heme oxygenase‐1 and NAD(P)H: quinone oxidoreductase 1, along with antioxidant enzymes including reduced glutathione, catalase, and superoxide dismutase with simultaneous reduction in the lipid peroxidation product malondialdehyde. Meanwhile, it recovered NAD+/NADH ratios and subsequently elevated the protein levels of sirtuin‐1 (SIRT‐1), farnesoid X receptor (FXR), and phosphorylated AMP‐activated protein kinase (p‐AMPK). Collectively, these findings suggest a protective role of β‐LAP against DOX‐induced hepatotoxicity by partly regulating the NAD+/SIRT‐1/FXR/p‐AMPK axis. [ABSTRACT FROM AUTHOR]

Inflammatory responses by macrophages have been pivotal in the pathogenesis of various diseases. We previously demonstrated the anti-inflammatory effects of ginsenoside compound K (GCK) through sirtuin 1 (SIRT1) activation in lipopolysaccharide-treated macrophages. This study extended the efficacy of GCK in mitigating ethanol-induced inflammation in macrophages through the interplay between SIRT1 and estrogen receptor α (ERα). Ethanol elevated inflammatory and oxidative stress genes with reduced SIRT1 expression. GCK reversed these effects, concomitantly inhibiting M1 polarization in macrophages. The efficacy of GCK in modulating ethanol-altered glycolysis and NAD+ salvage pathway was demonstrated through its interaction with SIRT1 and ERα. Activation of SIRT1 by GCK leads to the activation of ERα, and vice versa, suggesting a synergistic relationship between SIRT1 and ERα mediated by GCK. In conclusion, GCK exhibited anti-inflammatory and antioxidant properties, which may counteract energy metabolism disruptions in ethanol-stimulated macrophages, through the interplay between SIRT1 and ERα.

Aims and objectives: Astragaloside IV (AS-IV) has been found to possess anti-oxidative, anti-inflammatory, and anti-apoptotic properties, but its effect on atrial fibrosis is yet to be determined. This research investigates the protective role of AS-IV in angiotensin II (Ang II)-induced atrial fibrosis and atrial fibrillation (AF). Methods: C57BL/6 male mice aged 8–10 weeks (n = 40) were subcutaneously administered Ang II (2.0 mg/kg/day) or saline, with AS-IV (80 mg/kg) intraperitoneally administered 2 h before Ang II infusion for 4 weeks. Biochemical, histological, and morphological analyses were carried out. Using transesophageal burst pacing, AF was generated in vivo. Results: Here, we report that AS-IV treatment inhibited Ang II-induced AF development in mice (58 ± 5.86 vs 15.13 ± 2.16 %, p

The antibiotic heliomycin (resistomycin), which is generated from Streptomyces resistomycificus, has multiple activities, including anticancer effects. Heliomycin was first described in the 1960s, but its clinical applications have been hindered by extremely low solubility. A series of 4-aminomethyl derivatives of heliomycin were synthesized to increase water solubility; studies showed that they had anti-proliferative effects, but the drug targets remained unknown. In this study, we conducted cellular thermal shift assays (CETSA) and molecular docking simulations to identify and validate that heliomycin and its water-soluble derivative, 4-(dimethylaminomethyl)heliomycin (designated compound 4-dmH) engaged and targeted with sirtuin-1 (SIRT1) in p53-functional SAS and p53-mutated HSC-3 oral cancer cells. We further addressed the cellular outcome of SIRT1 inhibition by these compounds and found that, in addition to SIRT1, the water-soluble 4-dmH preferentially targeted a tumor-associated NADH oxidase (tNOX, ENOX2). The direct binding of 4-dmH to tNOX decreased the oxidation of NADH to NAD+ which diminished NAD+-dependent SIRT1 deacetylase activity, ultimately inducing apoptosis and significant cytotoxicity in both cell types, as opposed to the parental heliomycin-induced autophagy. We also observed that tNOX and SIRT1 were both upregulated in tumor tissues of oral cancer patients compared to adjacent normal tissues, suggesting their clinical relevance. Finally, the better therapeutic efficacy of 4-dmH was confirmed in tumor-bearing mice, which showed greater tNOX and SIRT1 downregulation and tumor volume reduction when treated with 4-dmH compared to heliomycin. Taken together, our in vitro and in vivo findings suggest that the multifaceted properties of water-soluble 4-dmH enable it to offer superior antitumor value compared to parental heliomycin, and indicated that it functions through targeting the tNOX-NAD+-SIRT1 axis to induce apoptosis in oral cancer cells.

Osteoarthritis (OA) is a degenerative disease characterised by articular cartilage destruction, and its complex aetiology contributes to suboptimal clinical treatment outcomes. A close association exists between glucose metabolism dysregulation and OA pathogenesis. Owing to the unique environment of low oxygen and glucose concentrations, chondrocytes rely heavily on their glycolytic capacity, exhibiting distinct spatiotemporal differences. However, under pathological stimulation, chondrocytes undergo excessive glycolytic activity while mitochondrial respiration and other branches of glucose metabolism are compromised. This metabolic change induces cartilage degeneration by reprogramming the inflammatory responses. Sirtuins, a highly conserved family of nicotinamide adenine dinucleotide (NAD+)-dependent deacetylases, regulate glucose metabolism in response to energy fluctuations in different cellular compartments，alleviating metabolic stress. SIRT1, the most extensively studied sirtuin, participates in maintaining glucose homeostasis in almost all key metabolic tissues. While actively contributing to the OA progression and displaying diverse biological effects in cartilage protection, SIRT1’s role in regulating glucose metabolism in chondrocytes has not received sufficient attention. This review focuses on discussing the beneficial role of SIRT1 in OA progression from a metabolic regulation perspective based on elucidating the primary characteristics of chondrocyte glucose metabolism. We also summarise the potential mechanisms and therapeutic strategies targeting SIRT1 in chondrocytes to guide clinical practice and explore novel therapeutic directions.

Novel therapeutic strategies are required for the effective and lasting treatment of metastatic melanoma, one of the deadliest skin malignancies. In this study, we determined the antimelanoma efficacy of 4-bromo-resveratrol (4-BR), which is a small-molecule dual inhibitor of SIRT1 and SIRT3, in a BrafV600E/PtenNULL mouse model that recapitulates human disease, including metastases. Tumors were induced by topical application of 4-hydroxy-tamoxifen on shaved backs of mice aged 10 weeks, and the effects of 4-BR (5‒30 mg/kg of body weight, intraperitoneally, 3 days per week for 5 weeks) were assessed on melanoma development and progression. We found that 4-BR at a dose of 30 mg/kg significantly reduced the size and volume of primary melanoma tumors as well as lung metastasis with no adverse effects. Furthermore, mechanistic studies on tumors showed significant modulation in the markers of proliferation, survival, and melanoma progression. Because SIRT1 and SIRT3 are linked to immunomodulation, we performed differential gene expression analysis using a PanCancer Immune Profiling Panel (770 genes). Our data showed that 4-BR significantly downregulated the genes related to metastasis promotion, chemokine/cytokine regulation, and innate/adaptive immune functions. Overall, inhibition of SIRT1 and SIRT3 by 4-BR is a promising antimelanoma therapy with antimetastatic and immunomodulatory activities warranting further detailed studies, including clinical investigations.

Background & aimsAlthough Ikaros (IKZF1) is a well-established transcriptional regulator in leukocyte lymphopoiesis and differentiation, its role in myeloid innate immune responses remains unclear. Sirtuin 1 (SIRT1) is a histone/protein deacetylase involved in cellular senescence, inflammation, and stress resistance. Whether SIRT1 signaling is essential in myeloid cell activation remains uncertain, while the molecular communication between Ikaros and SIRT1, two major transcriptional regulators, has not been studied.MethodsWe undertook molecular and functional studies to interrogate the significance of the myeloid Ikaros-SIRT1 axis in innate immune activation and whether it may serve as a homeostatic sentinel in human liver transplant recipients (hepatic biopsies) and murine models of sterile hepatic inflammation (liver warm ischemia-reperfusion injury in wild-type, myeloid-specific Sirt1-knockout, and CD11b-DTR mice) as well as primary bone marrow-derived macrophage (BMM) cultures (Ikaros silencing vs. overexpression).ResultsIn our clinical study, we identified increased post-reperfusion hepatic Ikaros levels, accompanied by augmented inflammasome signaling yet depressed SIRT1, as a mechanism of hepatocellular damage in liver transplant recipients. In our experimental studies, we identified infiltrating macrophages as the major source of Ikaros in IR-stressed mouse livers. Then, we demonstrated that Ikaros-regulated pyroptosis - induced by canonical inflammasome signaling in BMM cultures - was SIRT1 dependent. Consistent with the latter, myeloid-specific Ikaros signaling augmented hepatic pyroptosis to aggravate pro-inflammatory responses in vivo by negatively regulating SIRT1 in an AMPK-dependent manner. Finally, myeloid-specific SIRT1 was required to suppress pyroptosis, pro-inflammatory phenotype, and ultimately mitigate hepatocellular injury in ischemia-stressed murine livers.ConclusionThese findings identify the Ikaros-SIRT1 axis as a novel mechanistic biomarker of pyroptosis and a putative checkpoint regulator of homeostasis in response to acute hepatic stress/injury in mouse and human livers.Lay summaryThis report describes how crosstalk between Ikaros and SIRT1, two major transcriptional regulators, influence acute hepatic inflammation in murine models of liver ischemia-reperfusion injury and liver transplant recipients. We show that the myeloid Ikaros-SIRT1 axis regulates inflammasome-pyroptotic cell death and hepatocellular damage in stressed livers. Thus, the Ikaros-SIRT1 axis may serve as a novel checkpoint regulator that is required for homeostasis in response to acute liver injury in mice and humans.

Background Acute kidney injury (AKI) is a serious pathology that causes dysfunction in concentrating urine due to kidney damage, resulting in blood pressure dysregulation and increased levels of toxic metabolites. Dexpanthenol (DEX), a pantothenic acid analog, exhibits anti-inflammatory and anti-apoptotic properties in various tissues. This study investigated the protective effects of DEX against systemic inflammation-induced AKI. Methods Thirty-two female rats were randomly assigned to the control, lipopolysaccharide (LPS), LPS+DEX, and DEX groups. LPS (5 mg/kg, single dose on the third day, 6 h before sacrifice) and DEX (500 mg/kg/day for 3 days) were administered intraperitoneally. After sacrifice, blood samples and kidney tissues were collected. Hematoxylin and eosin, caspase-3 (Cas-3), and tumor necrosis factor alpha (TNF-α) staining were performed on the kidney tissues. The total oxidant status (TOS) and total antioxidant status were measured using spectrophotometric methods. Aquaporin-2 (AQP-2), silent information regulator 1 (SIRT1), and interleukin-6 (IL-6) were detected using quantitative reverse transcription-polymerase chain reaction analysis. Results Histopathological analysis revealed that DEX treatment ameliorated histopathological changes. In the LPS group, an increase in the blood urea nitrogen, creatinine, urea, IL-6, Cas-3, TNF-α, and TOS levels and oxidative stress index was observed compared with the control group, whereas AQP-2 and SIRT1 levels decreased. DEX treatment reversed these effects. Conclusions DEX was found to effectively prevent inflammation, oxidative stress, and apoptosis in the kidneys via the SIRT1 signaling pathway. These protective properties suggest DEX’s potential as a therapeutic agent for the treatment of kidney pathologies.

NAD+-dependent deacetylase sirtuin-1 (Sirt1) belongs to the sirtuins family, known to be longevity regulators, and exerts a key role in the prevention of vascular aging. By aging, the expression levels of Sirt1 decline with a severe impact on vascular function, such as the rise of endothelial dysfunction, which in turn promotes the development of cardiovascular diseases. In this context, the impact of Sirt1 activity in preventing endothelial senescence is particularly important. Given the key role of Sirt1 in counteracting endothelial senescence, great efforts have been made to deepen the knowledge about the intricate cross-talks and interactions of Sirt1 with other molecules, in order to set up possible strategies to boost Sirt1 activity to prevent or treat vascular aging. The aim of this review is to provide a proper background on the regulation and function of Sirt1 in the vascular endothelium and to discuss the recent advances regarding the therapeutic strategies of targeting Sirt1 to counteract vascular aging.