SIRT1 inhibition causes oxidative stress and inflammation in patients with coronary artery disease

The role of sirtuins and uncoupling proteins on vascular aging: The Northern Manhattan Study experience

Aging affects all organs. Arteries, in particular, are among the most affected. Vascular aging (VA) is defined as age-associated changes in function and structure of vessels. Classical VA phenotypes are carotid intima-media thickness (IMT), carotid plaque (CP), and arterial stiffness (STIFF). Individuals have different predisposition to these VA phenotypes and their associated risk of cardiovascular events. Some develop an early vascular aging (EVA), and others are protected and identified as having supernormal vascular aging (SUPERNOVA). The mechanisms leading to these phenotypes are not well understood. In the Northern Manhattan Study (NOMAS), we found genetic variants in the 7 Sirtuins (SIRT) and 5 Uncoupling Proteins (UCP) to be differently associated with risk to developing VA phenotypes. In this article, we review the results of genetic-epidemiology studies to better understand which of the single nucleotide polymorphisms (SNPs) in SIRT and UCP are responsible for both EVA and SUPERNOVA.

Nuclear proteins and diabetic retinopathy: a review

Diabetic retinopathy (DR) is an eye disease that causes blindness and vision loss in diabetic. Risk factors for DR include high blood glucose levels and some environmental factors. The pathogenesis is based on inflammation caused by interferon and other nuclear proteins. This review article provides an overview of DR and discusses the role of nuclear proteins in the pathogenesis of the disease. Some core proteins such as MAPK, transcription co-factors, transcription co-activators, and others are part of this review. In addition, some current advanced treatment resulting from the role of nuclear proteins will be analyzes, including epigenetic modifications, the use of methylation, acetylation, and histone modifications. Stem cell technology and the use of nanobiotechnology are proposed as promising approaches for a more effective treatment of DR.

SIRT1 signaling pathways in sarcopenia: Novel mechanisms and potential therapeutic targets

Sarcopenia is an aging-related skeletal disease characterized by decreased muscle mass, strength, and physical function, severely affecting the quality of life (QoL) of the elderly population. Sirtuin 1 (SIRT1), as a nicotinamide adenine dinucleotide (NAD+)-dependent histone deacetylases, has been reported to participate in various aging-related signaling pathways and exert protective effect on many human diseases. SIRT1 functioned as an important role in the occurrence and progression of sarcopenia through regulating key pathways related to protein homeostasis, apoptosis, mitochondrial dysfunction, insulin resistance and autophagy in skeletal muscle, including SIRT1/Forkhead Box O (FoxO), AMP-activated protein kinase (AMPK)/SIRT1/nuclear factor κB (NF-κB), SIRT1/p53, AMPK/SIRT1/peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α), and SIRT1/live kinase B1 (LKB1)/AMPK pathways. However, the specific mechanisms of these processes have not been fully illuminated. Currently, several SIRT1-mediated interventions on sarcopenia have been preliminarily developed, such as SIRT1 activator polyphenolic compounds, exercising and calorie restriction. In this review, we summarized the predominant mechanisms of SIRT1 involved in sarcopenia and therapeutic modalities targeting the SIRT1 signaling pathways for the prevention and prognosis of sarcopenia.

Decreased SIRT1 mRNA expression in peripheral blood mononuclear cells from patients with neuromyelitis optica spectrum disorders

OBJECTIVE

Sirtuin (SIRT)1, as a molecular link between immunity and metabolic pathways, is a key immune response regulator. The significance of SIRT1 in peripheral blood mononuclear cells (PBMCs) of neuromyelitis optica spectrum disorder (NMOSD) has not been investigated. Here, we aimed to evaluate the SIRT1 mRNA level in PBMCs of patients with NMOSD and its clinical relevance and explore the potential mechanism of SIRT1 action.

METHODS

A total of 65 patients with NMOSD and 60 normal controls from North China were enrolled. Using real-time fluorescence quantitative-polymerase chain reaction, mRNA levels were detected in PBMCs, and protein levels were detected using western blotting.

RESULTS

Compared to the healthy controls and chronic-phase patients with NMOSD, SIRT1 mRNA and protein levels in PBMCs of NMOSD patients with acute attack were significantly downregulated (p < 0.0001). ∆EDSS scores (EDSS scores in the acute phase-EDSS scores before the recent attack) were higher in NMOSD patients with low SIRT1 mRNA level than in patients with high SIRT1 expression (p = 0.042). SIRT1 mRNA level in patients with acute-phase NMSOD was positively correlated with lymphocyte and monocyte counts and negatively correlated with neutrophil counts and the neutrophil-to-lymphocyte ratio. Furthermore, the transcription factor FOXP3 mRNA level was significantly positively correlated with the SIRT1 mRNA level in PBMCs of patients with acute-phase NMOSD.

CONCLUSIONS

Our study indicated that SIRT1 mRNA expression was downregulated in the PBMCs of patients with acute-phase NMOSD, and its level was correlated with the clinical parameters of the patients, suggesting a potential role of SIRT1 in NMOSD.

MiR-217 Regulates SIRT1 Expression and Promotes Inflammatory and Apoptotic Responses in Osteoarthritis

Previous studies have reported miR-217 uregulation in age-related pathologies. We investigated the impact of miR-217-5p on sirtuin 1 (SIRT1) regulation in human osteoarthritic (OA) chondrocytes. MiR-217 target enrichment analyses were performed using three public databases, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes. MiR-217-5p expression levels were quantified in normal and OA chondrocytes. SIRT1 expression levels, nuclear factor kappa-B p65 subunit (NF-κBp65) and p53 acetylation levels, and expression levels of OA-related pro-inflammatory markers [tumor necrosis factor α (TNFα), interleukin 1β (IL-1β), IL-6], pro-apoptotic markers [Bax, pro-caspase 3, cleaved caspase 3] and matrix regulators [matrix metalloproteinase (MMP)-1, MMP-13, MMP-9, Collagen 2 (COL2A1), Aggrecan (ACAN)] were evaluated in miR-217 mimic-treated and/or miR-217 inhibitor-treated OA chondrocytes, with/without subsequent treatment with siRNA against SIRT1 (siSIRT1). MiR-217-5p was upregulated in OA chondrocytes, while target prediction/enrichment analyses revealed SIRT1 as miR-217 target-gene. Deacetylation of NF-κBp65 and p53 in miR-217 inhibitor-treated OA chondrocytes was reversed by siSIRT1 treatment. MiR-217 inhibitor-treated OA chondrocytes showed increased COL2A1, ACAN and decreased IL-1β, IL-6, TNFα, Bax, cleaved caspase 3 and MMPs expression levels, which were reversed following miR-217 inhibitor/siSIRT1 treatment. Our findings highlight the impact of miR-217-5p on SIRT1 downregulation contributing to OA pathogenesis.

Cardioprotective effects of calorie restriction against inflammation and apoptosis in ovariectomized obese rats: Role of classical estrogen receptors and SIRT1

AIM

Obesity is a metabolic complication linked with bad eating habits and a sedentary lifestyle, and the heart is one of the target organs damaged by it. Estrogen deficiency during menopause worsens the situation. Calorie restriction (CR) can contribute to reducing cardiovascular disease (CVD) in postmenopausal conditions. Thus, the effects of CR on inflammation and apoptosis in ovariectomized rats' hearts with obesity were studied.

METHOD

Female Wistar rats were categorized into Sham and OVX (ovariectomized) groups and received a standard diet (SD) or high-fat diet (60%HFD) or calorie restriction (30% CR) for 16 weeks. The real-time PCR method was used to evaluate the inflammatory markers and estrogen receptors gene expression. Western-blot and ELISA methods were respectively used for the measurement of apoptosis and SIRT1 protein expression.

RESULTS

HFD led to the elevation of body weight, IL-6 (interleukin-6) and TNF-α (tumor necrosis factor-α) and reduction of IL-10 (interleukin-10) gene expressions, and also an increment in protein levels of cleaved caspase-3, Bax and Bax/Bcl2 ratio and decrement in Bcl-2 in OVX rats (P < 0.001). Additionally, HFD reduced SIRT1 (sirtuin1) protein levels, ERα (estrogen receptor α), and ERβ (estrogen receptor β) gene expressions (P < 0.001). In contrast, CR declined body weight, IL-6 and TNF-α (P < 0.001), increased IL-10 expressions (P < 0.05), decreased cleaved caspase-3 (P < 0.001), Bax (P < 0.01), and Bax/Bcl2 ratio (P < 0.05), enhanced Bcl-2 (P < 0.001), increased SIRT1 (P < 0.05) and ERα (P < 0.001) and ERβ (P < 0.01) expressions.

CONCLUSION

CR through the SIRT1 regulation and estrogen receptors attenuate obesity-induced-cardiac inflammation and apoptosis. CR can be a cardioprotective candidate in postmenopausal conditions.

Involvement of Sirtuin 1 in the Growth Hormone/Insulin-like Growth Factor 1 Signal Transduction and Its Impact on Growth Processes in Children

The regulation of growth processes in children depends on the synthesis of growth hormone (GH) and insulin-like growth factor 1 (IGF-1). Insulin-like growth factor 1, which is mainly secreted in the liver in response to GH, is the main peripheral mediator of GH action. Newly discovered factors regulating GH secretion and its effects are being studied recently. One of them is sirtuin 1 (SIRT1). This NAD+-dependent deacetylase, by modulating the JAK2/STAT pathway, is involved in the transduction of the GH signal in hepatocytes, leading to the synthesis of IGF-1. In addition, it participates in the regulation of the synthesis of GHRH in the hypothalamus and GH in the somatotropic cells. SIRT1 is suggested to be involved in growth plate chondrogenesis and longitudinal bone growth as it has a positive effect on the epiphyseal growth plate. SIRT1 is also implicated in various cellular processes, including metabolism, cell cycle regulation, apoptosis, oxidative stress response, and DNA repair. Thus, its expression varies depending on the different metabolic states. During malnutrition, SIRT1 blocks GH signal transduction in hepatocytes to reduce the IGF-1 secretion and prevent hypoglycemia (i.e., it causes transient GH resistance). In this review, we focused on the influence of SIRT1 on GH signal transduction and the implications that may arise for growth processes in children.

Evaluation of Rosuvastatin Therapy on SIRT1 Gene Expression in Patients with Multiple Sclerosis: An Uncontrolled Clinical Trial

Background

Multiple sclerosis (MS) is a chronic autoimmune disease. Current medications have some limitations such as low efficacy and high side effects. In recent years, statins have been raised as potential therapeutics for MS treatment with minimal complications. In addition, patient monitoring using suitable molecular markers is necessary for treatment response evaluation.

Objective

The aim of the present study was the evaluation of SIRT1 gene expression changes following rosuvastatin therapy in patients with MS.

Methods

This before-after uncontrolled clinical trial study was performed on 25 patients with MS. Patients were treated with 20 mg rosuvastatin daily for 3 months. The Expanded Disability Status Scale (EDSS) was measured before and after statin therapy. Blood samples were taken from patients 2 times, before and after statin therapy, and centrifuged for white blood cell isolation. Total RNA was extracted using RNX-plus reagent, and complementary DNA was synthesized using Pars Tous cDNA Synthesis Kit. Real-time polymerase chain reaction was done using SYBR blue master mix and gene-specific primers in Roche light cycler. Patients' information was recorded using a checklist. Data analysis was performed using SPSS version 23 and Graph Pad version 9 software and P < 0.05 was considered a significant level.

Results

SIRT1 was significantly upregulated in MS patients after statin therapy. Subsequently, EDSS of patients was decreased along with the increase in SIRT1 gene expression, although EDSS changes were not significant (P > 0.05). Pearson correlation test showed no significant relationship between EDSS and SIRT1 gene expression (P > 0.05). No significant relationship was observed between SIRT1 expression or EDSS levels with patients' age, sex, weight, height, and body mass index and administrated drugs (P > 0.05).

Conclusions

SIRT1 potentially is a sensitive and reliable biomarker for patients with MS monitoring during statin therapy.

Effects of Astaxanthin supplementation on selected metabolic parameters, anthropometric indices, Sirtuin1 and TNF-α levels in patients with coronary artery disease: A randomized, double-blind, placebo-controlled clinical trial

Background

Atherosclerosis can develop as a result of an increase in oxidative stress and concurrently rising levels of inflammation. Astaxanthin (AX), a red fat-soluble pigment classified as a xanthophyll, may be able to prevent the vascular damage induced by free radicals and the activation of inflammatory signaling pathways. The objective of the current study is to assess the effects of AX supplementation on cardiometabolic risk factors in individuals with coronary artery disease (CAD).

Methods

This randomized double-blind placebo-controlled clinical trial was conducted among 50 CAD patients. Participants were randomly allocated into two groups to intake either AX supplements (12 mg/day) or placebo for 8 weeks. Lipid profile, glycemic parameters, anthropometric indices, body composition, Siruin1 and TNF-α levels were measured at baseline and after 8 weeks.

Results

Body composition, glycemic indices, serum levels of TNF-α, Sirtuin1 did not differ substantially between the AX and placebo groups (p &gt; 0.05). The data of AX group showed significant reduction in total cholesterol (−14.95 ± 33.57 mg/dl, p &lt; 0.05) and LDL-C (−14.64 ± 28.27 mg/dl, p &lt; 0.05). However, TG and HDL-C levels could not be affected through AX supplementation.

Conclusion

Our results suggest that AX supplementation play a beneficial role in reducing some components of lipid profile levels. However, further clinical investigations in CAD patients are required to obtain more conclusive findings.

Clinical trial registration

www.Irct.ir., identifier IRCT20201227049857N1.

DNA methylation regulates Sirtuin 1 expression in osteoarthritic chondrocytes

PURPOSE

Sirtuin 1 (SIRT1) comprises a major anti-aging longevity factor with multiple protective effects on chondrocyte homeostasis. Previous studies have reported that downregulation of SIRT1 is linked to osteoarthritis (OA) progression. In this study, we aimed to investigate the role of DNA methylation on SIRT1 expression regulation and deacetylase activity in human OA chondrocytes.

MATERIALS AND METHODS

Methylation status of SIRT1 promoter was analyzed in normal and OA chondrocytes using bisulfite sequencing analysis. CCAAT/enhancer binding protein alpha (C/EBPα) binding to SIRT1 promoter was assessed by chromatin immunoprecipitation (ChIP) assay. Subsequently, C/EBPα's interaction with SIRT1 promoter and SIRT1 expression levels were evaluated after treatment of OA chondrocytes with 5-Aza-2'-Deoxycytidine (5-AzadC). Acetylation and nuclear levels of nuclear factor kappa-B p65 subunit (NF-κΒp65) and expression levels of selected OA-related inflammatory mediators, interleukin 1β (IL-1β) and IL-6 and catabolic genes (metalloproteinase-1 (MMP-1) and MMP-9) were evaluated in 5-AzadC-treated OA chondrocytes with or without subsequent transfection with siRNA against SIRT1.

RESULTS

Hypermethylation of specific CpG dinucleotides on SIRT1 promoter was associated with downregulation of SIRT1 expression in OA chondrocytes. Moreover, we found decreased binding affinity of C/EBPα on the hypermethylated SIRT1 promoter. 5-AzadC treatment restored C/EBPα's transcriptional activity inducing SIRT1 upregulation in OA chondrocytes. Deacetylation of NF-κΒp65 in 5-AzadC-treated OA chondrocytes was prevented by siSIRT1 transfection. Similarly, 5-AzadC-treated OA chondrocytes exhibited decreased expression of IL-1β, IL-6, MMP-1 and MMP-9 which was reversed following 5-AzadC/siSIRT1 treatment.

CONCLUSIONS

Our results suggest the impact of DNA methylation on SIRT1 suppression in OA chondrocytes contributing to OA pathogenesis.

Noninvasive Positron Emission Tomography Imaging of SIRT1 in a Model of Early-Stage Alcoholic Liver Disease

Accrued evidence has indicated that epigenetic mechanisms altered by alcohol have been implicated in the progression and development of alcoholic liver disease (ALD). SIRT1 plays an important role in ALD progression and has emerged as a promising therapeutic target for treating ALD. The purpose of this study is to investigate the efficacy of [¹¹C]WL-1 for quantitative imaging of SIRT1 in mouse models of early-stage ALD. Positron emission tomography/computerized tomography (PET/CT) imaging was carried out 60 min following the injection of [¹¹C]WL-1 in mouse models of early-stage ALD and normal control mice. The time-activity curves for ALD mouse livers showed remarkably decreased total uptake of [¹¹C]WL-1 relative to that for control mouse livers. Moreover, compared with the normal control mice, decreased uptake in the cortex, hippocampus, and cerebellum was also observed in early-stage ALD mice, while the uptake of [¹¹C]WL-1 in amygdala showed no significant changes. Western blot analysis confirmed that the protein levels of SIRT1 in the brains of early-stage ALD mice were decreased significantly when compared to the normal control mouse brains. Collectively, PET imaging with [¹¹C]WL-1 would facilitate future clinical studies, aiming to demonstrate the roles of SIRT1 in ALD.

MiR-214 Expression Is Elevated in Chronic Rhinosinusitis Mucosa and Regulates Lipopolysaccharide-Mediated Responses in Undifferentiated Human Nasal Epithelial Cell Culture

BACKGROUND

Chronic rhinosinusitis (CRS) is an inflammatory disorder of the upper airways. MicroRNAs (miRs) are reported to regulate several diverse physiological and pathological processes.

OBJECTIVE

This study aimed to evaluate the impact of miR-214 on lipopolysaccharide (LPS)-mediated inflammation, and mucin 5AC (MUC5AC) expression in human nasal epithelial cells.

METHODS

The expression of miR-214 was detected in CRS with polyps (CRSwNP) and CRS without polyps (CRSsNP) tissues. Cells were treated with LPS and a miR-214 inhibitor. The level of miR-214 was detected by quantitative real-time reverse transcriptase-PCR (qRT-PCR). The inflammatory cytokines (IL-6, IL-8, TNF, and IL-1β) and MUC5AC production were determined by qRT-PCR and ELISA. MUC5AC protein level was detected using western blot. Similarly, we determined the relationship between miR-214 and Sirtuin 1 (SIRT1) using the Dual luciferase activity assay.

RESULTS

miR-214 was increased in CRSwNP and CRSsNP tissues. LPS triggered the expression of miR-214, while miR-214 inhibition diminished the level of miR-214. MiR-214 inhibition prevented LPS-mediated the production of inflammatory cytokines. LPS treatment augmented MUC5AC mRNA, protein levels, and secretion, whereas miR-214 loss inhibited MUC5AC production in the presence of LPS. SIRT1 is a direct target of miR-214. Impairing SIRT1 by siRNA (siSIRT1) or EX527 (a selective SIRT1 inhibitor) reversed the effects of miR-214 inhibitor on inflammation and MUC5AC expression. Furthermore, miR-214 depression inhibited the STAT3/GDF15 pathway via targeting SIRT1. Upregulation of STAT3 or GDF15 partly abolished the anti-inflammatory roles of miR-214 inhibitor.

CONCLUSION

Taken together, miR-214 regulates LPS-mediated inflammation and MUC5AC expression via targeting SIRT1, and STAT3/GDF15 may involve in the regulation of miR-214 inhibitor on inflammation and MUC5AC expression.

Potential roles of endothelial cells-related non-coding RNAs in cardiovascular diseases

Endothelial dysfunction is identified by a conversion of the endothelium toward decreased vasodilation and prothrombic features and is known as a primary pathogenic incident in cardiovascular diseases. An insight based on particular and promising biomarkers of endothelial dysfunction may possess vital clinical significances. Currently, non-coding RNAs due to their participation in critical cardiovascular processes like initiation and progression have gained much attention as possible diagnostic as well as prognostic biomarkers in cardiovascular diseases. Emerging line of proof has demonstrated that abnormal expression of non-coding RNAs is nearly correlated with the pathogenesis of cardiovascular diseases. In the present review, we focus on the expression and functional effects of various kinds of non-coding RNAs in cardiovascular diseases and negotiate their possible clinical implications as diagnostic or prognostic biomarkers and curative targets.

Reverse expression pattern of sirtuin-1 and histone deacetylase-9 in coronary artery disease

BACKGROUND

SIRT1 and HDAC 9 genes are related to inflammation and may contribute to the pathogenesis of coronary artery disease (CAD). We aimed to evaluate the expression level, methylation profile and polymorphisms of these genes in CAD patients.

METHODS

In this study, 50 CAD patients and 50 healthy individuals were recruited. The expression level change was evaluated using the TaqMan Real-Time PCR method. The methylation of genes promoter and genotyping of polymorphisms were evaluated by the HRM.

RESULTS

The expression level of SIRT1 was reduced while the HDAC9 expression level showed a significant elevation (p < .001). The SIRT1 gene promoter was hypomethylated and the HDAC9 gene promoter was hypermethylated in CAD patients. Also, CG + GG genotype in SIRT1 and both genotypes in the HDAC9 gene were associated with expression change.

CONCLUSIONS

SIRT1 and HDAC9 genes, expression changes can be suggested as a potential biomarker for CAD detection.

microRNA-181c-5p stimulates the development of coronary artery disease by targeting SIRT1

OBJECTIVE

MicroRNA (miR) therapeutics is a promising approach to manage coronary artery disease (CAD). Herein, this research was aimed to explore miR-181c-5p-related mechanisms in CAD through regulating SIRT1.

METHODS

A CAD mouse model was established by feeding a high-fat diet in 8-week-old ApoE^-/- mice. miR-181c-5p, SIRT1, and acetylated p65 levels in mouse myocardial tissues were evaluated by RT-qPCR and Western blot. Hemodynamic parameters included the maximum rising rate of the left ventricular pressure (lv + dp/dtmax) and the time values from the onset of contraction to dp/dtmax (t-dp/dtmax), while hemorheological indices included whole blood viscosity (low shear, middle shear, or high shear), plasma viscosity, hematocrit, and platelet adhesion were measured. Tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and IL-6 were detected. Mouse pathological changes, degree of fibrosis, and cardiomyocyte apoptosis in myocardial tissues were assessed by HE, Masson, and TUNEL staining, respectively. The targeting relationship between miR-181c-5p and SIRT1 was verified by bioinformatics tools, dual luciferase reporter gene assay, and RNA pull-down assays.

RESULTS

In myocardial tissue of CAD mice, miR-181c-5p and acetylated p65 were upregulated while SIRT1 was downregulated. Downregulating miR-181c-5p or upregulating SIRT1 effectively ameliorated CAD by improving hemodynamics and hemorheology and reducing inflammation, pathological changes, degree of fibrosis, and cardiomyocyte apoptosis in myocardial tissues of mice. miR-181c-5p targeted SIRT1, and overexpression of SIRT1 relieved upregulated miR-181c-5p-induced injuries in CAD mice. Regulating miR-181c-5p and SIRT1 affected the acetylation of p65.

CONCLUSION

Downregulation of miR-181c-5p may ameliorate myocardial pathological changes and cardiomyocyte apoptosis in CAD by upregulating SIRT1 expression and decreasing acetylated p65 levels.

The sirtuin family in health and disease

Sirtuins (SIRTs) are nicotine adenine dinucleotide(+)-dependent histone deacetylases regulating critical signaling pathways in prokaryotes and eukaryotes, and are involved in numerous biological processes. Currently, seven mammalian homologs of yeast Sir2 named SIRT1 to SIRT7 have been identified. Increasing evidence has suggested the vital roles of seven members of the SIRT family in health and disease conditions. Notably, this protein family plays a variety of important roles in cellular biology such as inflammation, metabolism, oxidative stress, and apoptosis, etc., thus, it is considered a potential therapeutic target for different kinds of pathologies including cancer, cardiovascular disease, respiratory disease, and other conditions. Moreover, identification of SIRT modulators and exploring the functions of these different modulators have prompted increased efforts to discover new small molecules, which can modify SIRT activity. Furthermore, several randomized controlled trials have indicated that different interventions might affect the expression of SIRT protein in human samples, and supplementation of SIRT modulators might have diverse impact on physiological function in different participants. In this review, we introduce the history and structure of the SIRT protein family, discuss the molecular mechanisms and biological functions of seven members of the SIRT protein family, elaborate on the regulatory roles of SIRTs in human disease, summarize SIRT inhibitors and activators, and review related clinical studies.

Chemical composition and anti-aging effects of standardized herbal chicken essence on D-galactose- induced senescent mice

This study aimed to examine the chemical and anti-aging properties of chicken essence (CE) prepared with Sesamum indicum, Angelica acutiloba, and Zingiber officinale (HCE). HCE was analyzed for nutritional and phytochemical composition, and its anti-aging effects were investigated on the D-galactose (Gal)-induced aging mice. Results showed that HCE possessed significantly higher calories and contents of valine and total phenols than CE; it also contained significant amounts of ferulic acid, sesamin, and sesamolin. HCE significantly decreased MDA and NO levels in serum and liver and increased liver GSH levels in the D-Gal-induced mice. HCE greatly enhanced SOD and CAT activities in serum and liver, and liver GPx activity, as well as upregulating SIRT1 expression and downregulating TNF-α, IL-1β, IL-6, iNOS, Cox-2, and MCP-1 expression in liver tissues. This study demonstrates that HCE was effective in suppressing the aging process through enhancing antioxidant and anti-inflammatory activities and modulating the aging-related gene expression.

Selenium alleviates heart remodeling through Sirt1/AKT/GSK-3β pathway

Selenium, reported as an important medium for maintaining the body's homeostasis, acts to have multiple bioeffects including anti-inflammatory, anti-oxidant and anti-apoptosis effects. However, its role in heart failure still remains unclear. In this study, we explored the effects of selenium on heart failure and its possible mechanism. The heart failure models were induced by aortic banding and isoproterenol. H&E, TUNEL and PSR staining were performed to detect the degree of cardiomyocyte hypertrophy, apoptosis rates and heart fibrosis, respectively. Real-time quantitative polymerase chain reaction (qRT-PCR) was used to detect different mRNA levels, and western blot was applied to assess the expressions of relative proteins. Immunofluorescence staining was used to evaluate α-SMA density. We first found that treatment of selenium alleviated heart fibrosis and the development of heart failure but not cardiomyocyte cross sectional areas. Besides, selenium improved heart levels of superoxide dismutase2 (SOD2), glutathione peroxidase (Gpx) and glutathione (GSH) and the activity of SOD, accompanied by decreased apoptosis rate. In addition, our in vitro study has shown that selenium reduced mRNA levels of collagen Ⅰ and collagen III, expressions of a-SMA, p-AKT/AKT and p-GSK-3β/ GSK-3β, apoptosis rates and reactive oxygen species (ROS) levels in H9C2 cardio-myoblasts treated with TGF-β1. Moreover, the level of Sirt1 was found to be up-regulated by selenium which effects were weakened after the administration of small interfering RNA (siRNA)-Sirt1 or EX527 (inhibitor of Sirt1). Our current results have demonstrated that the protective effects of selenium on heart hypertrophy is through the regulation of Sirt1 and AKT/GSK-3β pathway.

Horizons in Human Aging Neuroscience: From Normal Neural Aging to Mental (Fr)Agility

While aging is an important risk factor for neurodegenerative disorders such as Alzheimer’s disease and Parkinson’s disease, age-related cognitive decline can also manifest without apparent neurodegenerative changes. In this review, we discuss molecular, cellular, and network changes that occur during normal aging in the absence of neurodegenerative disease. Emerging findings reveal that these changes include metabolic alterations, oxidative stress, DNA damage, inflammation, calcium dyshomeostasis, and several other hallmarks of age-related neural changes that do not act on their own, but are often interconnected and together may underlie age-related alterations in brain plasticity and cognitive function. Importantly, age-related cognitive decline may not be reduced to a single neurobiological cause, but should instead be considered in terms of a densely connected system that underlies age-related cognitive alterations. We speculate that a decline in one hallmark of neural aging may trigger a decline in other, otherwise thus far stable subsystems, thereby triggering a cascade that may at some point also incur a decline of cognitive functions and mental well-being. Beyond studying the effects of these factors in isolation, considerable insight may be gained by studying the larger picture that entails a representative collection of such factors and their interactions, ranging from molecules to neural networks. Finally, we discuss some potential interventions that may help to prevent these alterations, thereby reducing cognitive decline and mental fragility, and enhancing mental well-being, and healthy aging.

Association of Sirtuin Gene Polymorphisms with Susceptibility to Coronary Artery Disease in a North Chinese Population

Aims

Coronary artery disease (CAD) represents the leading cause of death worldwide. Accumulating evidence also suggests that sirtuins (SIRTS) have been associated with CAD. The present study was aimed at investigating the association between 12 gene polymorphisms for SIRTs and the development of CAD in a Chinese population.

Materials and Methods

12 SNPs (rs12778366 (T > C), rs3758391 (T > C), rs3740051 (A > G), rs4746720 (C > T), rs7895833 (G > A), rs932658 (A > C) for SIRT1, rs2015 (G > T) for SIRT2, rs28365927 (G > A), rs11246020 (C > T) for SIRT3, rs350844 (G > A), rs350846 (G > C), and rs107251 (C > T) for SIRT6) were selected and assessed in a cohort of 509 CAD patients and 552 matched healthy controls for this study. Genomic DNA from whole blood was extracted, and the SNPs were assessed using MassARRAY method.

Results

TT genotype for rs3758391 and GG genotype for rs7895833 of SIRT1 were at higher risk of CAD, whereas the CC genotype for rs4746720 of SIRT1 was associated with a significantly decreased risk of CAD. The A allele of the rs28365927 of SIRT3 showed a significant decreased risk association with CAD patient group (P = 0.014). Significant difference in genotypes rs350844 (G > A) (P = 0.004), rs350846 (G > C) (P = 0.002), and rs107251 (C > T) (P ≤ 0.01) for SIRT6 was also found between the CAD patients and the healthy controls. Haplotype CTA significantly increased the risk of CAD (P = 0.000118, OR = 1.497, 95%CI = 1.218–1.840), while haplotype GCG significantly decreases the risk of CAD (P = 0.000414, OR = 1.131, 95%CI = 0.791–1.619).

Conclusions

The SNP rs28365927 in the SIRT3 gene and SNP rs350844, rs350846, and rs107251 in the SIRT6 gene present significant associations with CAD in a north Chinese population. Haplotype CTA and GCG generated by rs350846/rs107251/rs350844 in the SIRT6 might also increase and decrease the risk of CAD, respectively.

Role of Mitophagy in Coronary Heart Disease: Targeting the Mitochondrial Dysfunction and Inflammatory Regulation

Coronary heart disease (CHD) is one of the main causes of death worldwide. In the past few decades, several in-depth research on the pathological mechanisms and effective treatment methods for CHD have been conducted. At present, the intervention of a variety of therapeutic drugs and treatment technologies have greatly reduced the burden on global public health. However, severe arrhythmia and myocardial fibrosis accompanying CHD in the later stages need to be addressed urgently. Mitochondria are important structural components for energy production and the main sites for aerobic respiration in cells. Mitochondria are involved in arrhythmia, myocardial fibrosis, and acute CHD and play a crucial role in regulating myocardial ischemia/hypoxia. Mitochondrial dysfunction or mitophagy disorders (including receptor-dependent mitophagy and receptor-independent mitophagy) play an important role in the pathogenesis of CHD, especially mitophagy. Mitophagy acts as a “mediator” in the inflammatory damage of cardiomyocytes or vascular endothelial cells and can clear mitochondria or organelles damaged by inflammation under normal conditions. We reviewed experimental advances providing evidence that mitochondrial homeostasis or mitochondrial quality control are important in the pathological mechanism of CHD. Further, we reviewed and summarized relevant regulatory drugs that target mitochondrial function and quality control.

Role of Transcription Factor 7 like 2 and Silent Information Regulator 1 Genes in the Development of Cardiovascular Complications in a Group of Egyptian Patients with Chronic Kidney Disease

BACKGROUND: Sirtuins silent information regulator 1 (SIRT) is histone deacetylases that act as antioxidants and involved in the pathogenesis of cardiovascular diseases (CVD) which are the major complications of chronic kidney disease (CKD). Transcription factor 7-like 2 (TCF7L2) genetic polymorphisms could contribute to the risk of CVD as TCF7L2 proteins regulate vascular remodeling. AIM: We tried to demonstrate the role of genetic polymorphisms: rs7069102 and rs10823108 in SIRT1 gene and rs7903146 in TCF7L2 gene in the development of CVD in CKD Egyptian patients. METHODS: This study included 120 CKD patients (60 with CVD and 60 without CVD) and 60 age and sex-matched healthy subjects as a control group. Routine laboratory investigations were performed and genotyping for candidate single nucleotide polymorphisms was done by Taqman-real-time polymerase chain reaction. RESULTS: The frequency of the C allele of rs7069102 was significantly higher in CKD patients with CVD as compared to the normal control group (p < 0.001) and as compared to CKD patients without CVD (p < 0.001). Percentages of AG and GG genotypes of rs10823108 were significantly higher in CKD patients with CVD as compared to the normal control group (p = 0.002, 0.035, respectively). The frequency of the T allele of rs7903146 was significantly higher in CKD patients with CVD as compared to the normal control group (p < 0.001). CONCLUSION: We found that C allele of rs7069102, GG and AG genotypes of rs10823108 in the SIRT1 gene and T allele of rs7903146 in TCF7L2 gene have a potential role in the pathogenesis and the risk of CVD development in CKD Egyptian patients.

NAD+ improved experimental autoimmune encephalomyelitis by regulating SIRT1 to inhibit PI3K/Akt/mTOR signaling pathway

OBJECTIVE

To investigate the effect of NAD+ on thymus autophagy in experimental autoimmune encephalomyelitis (EAE) mice through SIRT1.

METHODS

Bioinformatic analysis was used to identify hub genes. Forty female C57BL/6 mice were randomly divided into 4 groups: control, EAE, NAD+, and NAD+ +SIRT1 inhibitor (SIRT-IN-3) groups and SIRT1 group. The NAD+ group and SIRT1 inhibitor group were treated with NAD+ drug and fed for 4 weeks. The neurological function scores were evaluated weekly. The thymus tissues of wild-type mice were removed, ground and filtered into single-cell suspension. MOG 35-55 (1 μg/mL) was given to primary thymic epithelial cells (TECs) to induce EAE model in vitro. The expression of LC-3A/B was observed by immunofluorescence. The expressions or the activation/phosphorylation of associated proteins were detected by Western blot.

RESULTS

Enrichment analysis showed PI3K-Akt-mTOR and autophagy pathway were main terms in EAE diseases, and the relationship between NAD+ and SIRT1. The activation of p-PI3K, p-Akt and p-mTOR were the highest in the EAE group consistent with decreased P62, Beclin1, LC-3A/B and SIRT1, and NAD+ reversed these results, furthermore SIRT1 inhibitor: SIRT-IN3 weakened the NAD+' effects in both in vivo and in vitro experiments. Immunofluorescence study in vivo and in vitro were accord with the results of western blot.

CONCLUSIONS

NAD+ exerted a protective effect on EAE mice by inhibiting PI3K/Akt/mTOR signaling pathway through SIRT1 in TECs, and prevented EAE mice from sustained damage.

Protective effects of resveratrol against 5-fluorouracil-induced oxidative stress and inflammatory responses in human keratinocytes

Although 5-fluorouracil (5-FU) is currently used as an anti-cancer chemotherapy, adverse effects such as oral mucositis potentially limit its clinical application. Additionally, the prevention of 5-FU-induced side effects are scarce. Resveratrol is known to decrease oxidative damage and inflammation. In this study, we examined the protective effects of resveratrol on 5-FU-induced oxidative stress and inflammatory responses in normal human keratinocytes (HaCaT cell) as in vitro oral mucositis model. HaCaT cells were exposed to 5-FU and simultaneously treated with resveratrol. The effects of resveratrol on 5-FU-induced cytotoxicity were evaluated using cell viability assay. The production of reactive oxygen species (ROS) was measured using a fluorescence spectrophotometer. The effects of resveratrol on nuclear factor erythroid 2-related factor 2 (Nrf2), silent information regulator transcript-1 (SIRT-1), and nuclear factor kappa B (NF-κB) signaling and inflammatory cytokine expression were examined. Resveratrol suppressed 5-FU-induced overproduction of ROS by upregulating anti-oxidant defense genes through Nrf2 activation and SIRT-1 expression. Concerning inflammatory responses, resveratrol suppressed the 5-FU-induced expression of pro-inflammatory cytokines via NF-κB nuclear translocation. Conversely, N-acetylcysteine reduced ROS levels without affecting the expression of pro-inflammatory cytokines. Resveratrol might be useful for preventing 5-FU-induced adverse effects by activating anti-oxidant and anti-inflammatory responses.

Sirtuin-1 in Egyptian patients with coronary artery disease

Background

Coronary artery disease (CAD) represents the leading cause of death worldwide. Animal and human studies have demonstrated that silent information regulator 1 (SIRT1) is involved in a wide range of physiological and pathological processes. This study aimed to measure the plasma level of SIRT1 in patients with CAD and explore its correlation with cardiovascular risk factors.

Results

Plasma SIRT1 was significantly lower in patients with chronic coronary syndrome (CCS) than in those in the control group and was significantly lower in patients with both acute myocardial infarction and unstable angina than in those in the control group and with CCS. Moreover, plasma SIRT1 was positively correlated with platelet count and negatively correlated with cholesterol and triglyceride levels.

Conclusions

The plasma level of SIRT1 is lower in patients with CAD compared to control and it could be a possible marker for this disease. Multi-center studies with follow-up measurements are recommended for further investigation.

Cissus quadrangularis extract attenuates diabetic nephropathy by altering SIRT1/DNMT1 axis

OBJECTIVES

Hyperglycemia-induced SIRT1, DNMT1, SODs, as well as oxidative stress, play a pivotal role in the progression of diabetic nephropathy. Cissus quadrangularis, holds antioxidant and hypoglycemic activity; however, a direct link between its activity and prevention of diabetic nephropathy has not been ascertained yet. Accordingly, we aimed to delineate the protective effect of ethanolic extract of Cissus quadrangularis (EECQ) against high-fat diet/streptozotocin (HFD/STZ) induced diabetic nephropathy rats.

METHODS

The control group was fed with a normal chow diet. Rats kept on an HFD for 12 weeks with a single low dose of STZ manifested the features of diabetic nephropathy. The treatment was done by the oral administration of EECQ (200 mg/kg) for six weeks (six rats in each group).

KEY FINDINGS

Treatment with EECQ demonstrated substantial attenuation of elevated insulin resistance, lipid profile and creatinine level. Additionally, EECQ restored albuminuria, glomerular filtration rate and creatinine clearance in diabetic nephropathy rats. Furthermore, HFD consumption in rats culminated in reduced SIRT1 and enhanced DNMT1 expression, nonetheless, rescued by EECQ. Moreover, EECQ augmented the SOD 1 and 3 levels, thereby safeguarded from oxidative damage and renal inflammation. Besides, treatment protected from renal fibrosis by downregulating TGFβ, Smad2/3 and col1/3 expression in diseased rats.

CONCLUSIONS

Thus, based on the above findings, we conclude that EECQ shows a protective effect against diabetic nephropathy.

Exercise and Cardioprotection in Coronary Artery Disease: A Pilot Quasi-Experimental Study

Sirtuin-1 is a protein that may orchestrate the cardioprotective effect of exercise by controlling cellular processes. This pilot study assessed the feasibility of performing a quasi-experimental study in this area. Patients with postacute myocardial infarction were recruited across four hospital sites in the United Kingdom. The participants were offered one weekly exercise session at Phase-III and Phase-IV cardiac rehabilitation (CR). Measurements were obtained pre-Phase-III CR (Week 1), post-Phase-III CR (Week 8), and post-Phase-IV CR (Week 22). Twenty-eight patients were recruited (79% male, 100% White, 60.2 ± 10.5 years old). The recruitment rate was not fulfilled (<70% eligible patients recruited; 0.9 participants recruited per week over 30 weeks). The success criteria for dropout rate, adherence rate, and collection of sirtuin-1 measures were satisfied. A large increase in sirtuin-1 (0.14 ± 0.03, d ≥ 0.8) was seen after Phase-III and Phase-IV CR. Collectively, a quasi-experimental study is feasible with a revised recruitment strategy.

Nature versus Number: Monocytes in Cardiovascular Disease

Monocytes play a key role in cardiovascular disease (CVD) as their influx into the vessel wall is necessary for the development of an atherosclerotic plaque. Monocytes are, however, heterogeneous differentiating from classical monocytes through the intermediate subset to the nonclassical subset. While it is recognized that the percentage of intermediate and nonclassical monocytes are higher in individuals with CVD, accompanying changes in inflammatory markers suggest a functional impact on disease development that goes beyond the increased proportion of these ‘inflammatory’ monocyte subsets. Furthermore, emerging evidence indicates that changes in monocyte proportion and function arise in dyslipidemia, with lipid lowering medication having some effect on reversing these changes. This review explores the nature and number of monocyte subsets in CVD addressing what they are, when they arise, the effect of lipid lowering treatment, and the possible implications for plaque development. Understanding these associations will deepen our understanding of the clinical significance of monocytes in CVD.

Age-related changes of human serum Sirtuin6 in adults

Background

Aging is a natural life process and with an aging population, age-related diseases (e.g. type 2 diabetes mellitus (T2DM), atherosclerosis-based cardiovascular diseases) are the primary mortality cause in older adults. Telomerase is often used as an aging biomarker. Detection and characterization of novel biomarkers can help in a more specific and sensitive identification of a person’s aging status. Also, this could help in age-related diseases early prevent, ultimately prolonging the population’s life span. Sirtuin 6 (Sirt6) - a member of the Sirtuins NAD⁺-dependent histone deacetylases family - is mainly intracellularly expressed, and is reported to be involved in the regulation of aging and aging-related diseases. Whether serum Sirt6 is correlated with aging and could be used as an aging biomarker is unknown. In the present study, we aimed to investigate the age-related Sirt6 changes in the serum of human adults.

Methods

Participants were divided into three groups according to age: 20–30 years (Young); 45–55 years (Middle-aged); and ≥ 70 years (Old). The Sirt6 and telomerase serum concentrations were determined by ELISA. The Sirt6 and human telomerase reverse transcriptase (hTERT) expression in vessels from amputated human lower limbs were analyzed using real-time quantitative PCR (RT-qPCR) and immunohistochemical staining. The relationships between variables were evaluated by Pearson correlation analysis.

Results

The Sirt6 and telomerase serum levels reduced with an increase in age. A similar tendency was observed for Sirt6 and hTERT in the vessel. Serum levels of Sirt6 were higher in females compared with males. Pearson’s regression analysis revealed that the Sirt6 serum level positively correlated with telomerase (r = 0.5743) and both were significantly negatively correlated with age (r = − 0.5830 and r = − 0.5993, respectively).

Conclusions

We reported a negative correlation between serum Sirt6 concentration and aging in human beings. Therefore, the Sirt6 serum level is a potential sex-specific aging marker.

Role of Histone Deacetylases in Monocyte Function in Health and Chronic Inflammatory Diseases

Histone deacetylases (HDACs) are a family of 18 members that participate in the epigenetic regulation of gene expression. In addition to histones, some HDACs also deacetylate transcription factors and specific cytoplasmic proteins.Monocytes, as part of the innate immune system, maintain tissue homeostasis and help fight infections and cancer. In these cells, HDACs are involved in multiple processes including proliferation, migration, differentiation, inflammatory response, infections, and tumorigenesis. Here, a systematic description of the role that most HDACs play in these functions is reviewed. Specifically, some HDACs induce a pro-inflammatory response and play major roles in host defense. Conversely, other HDACs reprogram monocytes and macrophages towards an immunosuppressive phenotype. The right balance between both types helps monocytes to respond correctly to the different physiological/pathological stimuli. However, aberrant expressions or activities of specific HDACs are associated with autoimmune diseases along with other chronic inflammatory diseases, infections, or cancer.This paper critically reviews the interesting and extensive knowledge regarding the role of some HDACs in these pathologies. It also shows that as yet, very little progress has been made toward the goal of finding effective HDAC-targeted therapies. However, given their obvious potential, we conclude that it is worth the effort to develop monocyte-specific drugs that selectively target HDAC subtypes with the aim of finding effective treatments for diseases in which our innate immune system is involved.

Protective Effect of Nicorandil on Cardiac Microvascular Injury: Role of Mitochondrial Integrity

A major shortcoming of postischemic therapy for myocardial infarction is the no-reflow phenomenon due to impaired cardiac microvascular function including microcirculatory barrier function, loss of endothelial activity, local inflammatory cell accumulation, and increased oxidative stress. Consequently, inadequate reperfusion of the microcirculation causes secondary ischemia, aggravating the myocardial reperfusion injury. ATP-sensitive potassium ion (KATP) channels regulate the coronary blood flow and protect cardiomyocytes from ischemia-reperfusion injury. Studies in animal models of myocardial ischemia-reperfusion have illustrated that the opening of mitochondrial KATP (mito-KATP) channels alleviates endothelial dysfunction and reduces myocardial necrosis. By contrast, blocking mito-KATP channels aggravates microvascular necrosis and no-reflow phenomenon following ischemia-reperfusion injury. Nicorandil, as an antianginal drug, has been used for ischemic preconditioning (IPC) due to its mito-KATP channel-opening effect, thereby limiting infarct size and subsequent severe ischemic insult. In this review, we analyze the protective actions of nicorandil against microcirculation reperfusion injury with a focus on improving mitochondrial integrity. In addition, we discuss the function of mitochondria in the pathogenesis of myocardial ischemia.

Senescence in tissue samples of humans with age-related diseases: A systematic review

BACKGROUND

Higher numbers of senescent cells have been implicated in age-related disease pathologies. However, whether different diseases have different senescent phenotypes is unknown. Here we provide a systematic overview of the current available evidence of senescent cells in age-related diseases pathologies in humans and the markers currently used to detect senescence levels in humans.

METHODS

PubMed, Web of Science and EMBASE were systematically searched from inception to the 29^th of September 2019, using keywords related to 'senescence', 'age-related diseases' and 'biopsies'.

RESULTS

In total 12,590 articles were retrieved of which 103 articles were included in this review. The role of senescence in age-related disease has been assessed in 9 different human organ system and 27 different age-related diseases of which heart (27/103) and the respiratory systems (18/103) are the most investigated. Overall, 27 different markers of senescence have been used to determine cellular senescence and the cell cycle regulator p16^ink4a is most often used (23/27 age-related pathologies).

CONCLUSION

This review demonstrates that a higher expression of senescence markers are observed within disease pathologies. However, not all markers to detect senescence have been assessed in all tissue types.

Mangiferin prevents myocardial infarction-induced apoptosis and heart failure in mice by activating the Sirt1/FoxO3a pathway

Myocardial infarction (MI) commonly leads to cardiomyocyte apoptosis and heart failure. Mangiferin is a natural glucosylxanthone extracted from mango fruits and leaves, which has anti-apoptotic and anti-inflammatory properties in experimental cardiovascular diseases. In the present study, we investigated the role and detailed mechanism of mangiferin in MI. We used ligation of the left anterior descending coronary artery to establish an MI model in vivo, and cardiomyocyte-specific Sirt1 knockout mice were used to identify the mechanism of mangiferin. For in vitro studies, oxygen and glucose deprivation (OGD) was used to mimic ischaemia in H9c2 cardiomyocytes. In mice, mangiferin treatment increased Sirt1 expression after MI, significantly reduced the infarct area, and prevented MI-induced apoptosis and heart failure. Mangiferin reduced OGD-induced cellular apoptosis in H9c2 cells. Meanwhile, Sirt1 knockout/silencing abolished the protective effects of mangiferin. Further studies revealed that mangiferin increased FoxO3a deacetylation by up-regulating Sirt1, thus preventing apoptosis, and adenovirus-mediated constitutive acetylation of FoxO3a restricted the anti-apoptotic effects of mangiferin in vivo and in vitro. Our results indicate that mangiferin prevents cardiomyocyte apoptosis and the subsequent heart failure by activating the Sirt1/FoxO3a pathway in MI, and suggest that mangiferin may have an interesting potential in following studies towards clinical evaluation.

Suppression of microRNA-323-3p restrains vascular endothelial cell apoptosis via promoting sirtuin-1 expression in coronary heart disease

AIMS

Coronary heart disease (CHD), a chronic inflammatory condition of vascular endothelial cells (VECs), poses a serious threat to human health. Previous studies have found that microRNAs (miRNAs) are closely related to the occurrence and development of cardiac diseases. Therefore, this study focused on the regulation by miR-323-3p on the progression of CHD.

METHODS

Initially, we employed microarray-based gene expression profiling of CHD to identify differentially expressed miRNAs. Next, the expression of miR-323-3p and SIRT1 was detected by RT-qPCR in a rat model of CHD generated by feeding with a high-fat diet. The interaction between miR-323-3p and SIRT1 was identified using bioinformatics analysis and dual luciferase reporter gene assay. The expressions of miR-323-3p and SIRT1 were altered in CHD rats and vascular endothelial cells (VECs) to examine the specific effects on CHD.

RESULTS

miR-323-3p was observed to be highly-expressed in blood samples from patients with CHD or with mild atherosclerosis and in the rat model of CHD. SIRT1 was a target gene of miR-323-3p, which could downregulate SIRT1 expression. miR-323-3p overexpression or SIRT1 inhibition resulted in increased apoptosis of VECs, elevated ac-p65 protein expression and ratio of ac-p65/p65, and upregulated expression of NF-κB signaling pathway-related proteins. Besides, miR-323-3p inhibition or SIRT1 upregulation in the CHD rat model was found to significantly alleviate symptoms and decrease levels of proteins related to the ac-p65 and NF-κB signaling pathways.

CONCLUSION

Overall, the experimental data provide evidence that miR-323-3p suppression may restrain VEC apoptosis and prevent the resultant CHD progression via SIRT1-inactivatedNF-κB signaling pathway.

Oxidative Stress in Ischemic Heart Disease

One of the novel interesting topics in the study of cardiovascular disease is the role of the oxidation system, since inflammation and oxidative stress are known to lead to cardiovascular diseases, their progression and complications. During decades of research, many complex interactions between agents of oxidative stress, oxidation, and antioxidant systems have been elucidated, and numerous important pathophysiological links to na number of disorders and diseases have been established. This review article will present the most relevant knowledge linking oxidative stress to vascular dysfunction and disease. The review will focus on the role of oxidative stress in endotheleial dysfunction, atherosclerosis, and other pathogenetic processes and mechanisms that contribute to the development of ischemic heart disease.

Dilated cardiomyopathy impairs mitochondrial biogenesis and promotes inflammation in an age- and sex-dependent manner

Dilated cardiomyopathy (DCM) belongs to the myocardial diseases associated with a severe impairment of cardiac function, but the question of how sex and age affect this pathology has not been fully explored. Impaired energy homeostasis, mitochondrial dysfunction, and systemic inflammation are well-described phenomena associated with aging. In this study, we investigated if DCM affects these phenomena in a sex- and age-related manner. We analyzed the expression of mitochondrial and antioxidant proteins and the inflammatory state in DCM heart tissue from younger and older women and men. A significant downregulation of Sirt1 expression was detected in older DCM patients. Sex-related differences were observed in the phosphorylation of AMPK that only appeared in older males with DCM, possibly due to an alternative Sirt1 regulation mechanism. Furthermore, reduced expression of several mitochondrial proteins (TOM40, TIM23, Sirt3, and SOD2) and genes (cox1, nd4) was only detected in old DCM patients, suggesting that age has a greater effect than DCM on these alterations. Finally, an increased expression of inflammatory markers in older, failing hearts, with a stronger pro-inflammatory response in men, was observed. Together, these findings indicate that age- and sex-related increased inflammation and disturbance of mitochondrial homeostasis occurs in male individuals with DCM.

A Molecular Perspective on Sirtuin Activity

The protein acetylation of either the α-amino groups of amino-terminal residues or of internal lysine or cysteine residues is one of the major posttranslational protein modifications that occur in the cell with repercussions at the protein as well as at the metabolome level. The lysine acetylation status is determined by the opposing activities of lysine acetyltransferases (KATs) and lysine deacetylases (KDACs), which add and remove acetyl groups from proteins, respectively. A special group of KDACs, named sirtuins, that require NAD⁺ as a substrate have received particular attention in recent years. They play critical roles in metabolism, and their abnormal activity has been implicated in several diseases. Conversely, the modulation of their activity has been associated with protection from age-related cardiovascular and metabolic diseases and with increased longevity. The benefits of either activating or inhibiting these enzymes have turned sirtuins into attractive therapeutic targets, and considerable effort has been directed toward developing specific sirtuin modulators. This review summarizes the protein acylation/deacylation processes with a special focus on the current developments in the sirtuin research field.

Downregulation of Sirt1 is correlated to upregulation of p53 and increased apoptosis in epicardial adipose tissue of patients with coronary artery disease

The higher expression level of p53 in epithelial adipose tissue (EAT) has previously been reported in atherosclerosis. Since we hypothesized that the expression of p53 is modulated by Sirt1, the aim of this study was to determine the expression levels of Sirt1 and p53 and to investigate their correlation to apoptosis in EAT of patients with coronary artery disease (CAD). Thirty-five patients with more than 50 % stenosis in at least one of the main coronary arteries were considered as CAD group while 29 patients with no clinical signs of atherosclerosis who underwent open-heart surgery for valve replacement were classified as control group. EAT biopsy samples were collected from all participants during surgery. Sirt1, p53, Bax, and Bcl-2 gene expression levels were determined in EAT by qRT-PCR and Western blotting was carried out to assess Sirt1 and p53 protein levels. Hematoxylin and eosin staining was used for histopathological analysis. mRNA and protein levels of Sirt1 in EAT were significantly lower in patients with CAD compared with control group, whereas CAD patients showed greater p53 gene and protein expressions. In addition, inverse correlations were observed between Sirt1 and p53 at both mRNA and protein levels. The Bax and ratio of Bax/Bcl-2 gene expressions were higher in CAD group, but no difference was observed in Bcl-2 expression. Histopathological analysis showed apoptotic bodies and infiltrated immune cells in EAT of CAD group. Our results suggest that the Sirt1-p53 axis may involve in atherosclerosis by promotion of apoptosis.

Impact of circadian disruption on health; SIRT1 and Telomeres

Circadian clock is a biochemical oscillator in organisms that regulates the circadian rhythm of numerous genes over 24 h. The circadian clock is involved in telomere homeostasis by regulating the diurnal rhythms of telomerase activity, TERT mRNA level, TERRA expression, and telomeric heterochromatin formation. Particularly, CLOCK and BMAL1 deficiency contribute to telomere shortening by preventing rhythmic telomerase activity and TERRA expression, respectively. Telomere shortening increases the number of senescent cells with impaired circadian rhythms. In return, telomerase reconstitution improves impaired circadian rhythms of senescent cells. SIRT1 that is an NAD+-dependent deacetylase positively regulates circadian clock and telomere homeostasis. SIRT1 contributes to the circadian clock by mediating CLOCK/BMAL1 complex formation, BMAL1 transcription and PER2 disruption. On the other hand, SIRT1 ensures telomere homeostasis by inducing telomerase and shelterin protein expression and regulating telomere heterochromatin formation. SIRT1 inhibition leads to both circadian clock and telomeres dysfunction that inhibit its activity. In light of this current evidence, we could suggest that the BMAL1/CLOCK complex regulates the telomere homeostasis in SIRT1 dependent manner, and also telomere dysfunction inhibits circadian clock function by suppressing SIRT1 activity to induce age-related diseases. We consider that increasing SIRT1 activity can prevent age-related diseases and help healthy aging by protecting telomere integrity and circadian clock function for individuals subjected to circadian rhythm disruption such as shift works, individuals with sleep disorders, and in the elderly population.

MicroRNA‑138‑5p regulates the development of spinal cord injury by targeting SIRT1

MicroRNAs (miRs) play an important role in the development and progression of spinal cord injury (SCI). The role of miR-138-5p in SCI was investigated in the present study. The anti-inflammatory effects of miR-138-5p and underlying mechanisms were investigated in an SCI rat model and in vitro model. Reverse transcription-quantitative PCR (RT-qPCR) was used to examine the expression of miR-138-5p in the SCI in vivo and in vitro models, as well as patients with SCI; it was found that miR-138-5p was significantly upregulated in SCI. Bioinformatics and dual-luciferase reporter assays were performed to predict and confirm the binding sites between miR-138-5p and the 3′untranslated region of sirtuin 1 (SIRT1). Then, the expression of SIRT1 was detected via RT-qPCR and western blotting, indicating downregulation of SIRT1 in SCI. PC12 cells were transfected with miR-138-5p inhibitor, inhibitor control or miR-138-5p inhibitor + SIRT1 small interfering RNA for 48 h, and then subjected to lipopolysaccharide (100 ng/ml) treatment for 4 h. Then, MTT assay, flow cytometry and ELISA experiments were performed to analyze cell viability, apoptosis, and the levels of tumor necrosis factor-α, interleukin (IL)-1β and IL-6. Findings suggested that downregulation of miR-138-5p increased PC12 cell viability, inhibited cell apoptosis and attenuated proinflammatory responses, which may result in amelioration of SCI. However, all these effects were reversed by SIRT1 knockdown. Finally, it was observed that miR-138-5p altered the related protein expression of the PTEN/AKT pathway. These results indicated that miR-138-5p could regulate inflammatory responses and cell apoptosis in SCI models by modulating the PTEN/AKT signaling pathway via SIRT1, thus playing an important role in the development of SCI. Collectively, the present study demonstrated that miR-138-5p may be a novel therapeutic target for the treatment of SCI.

Reduced Sirtuin1 signalling exacerbates diabetic mice hindlimb ischaemia injury and inhibits the protective effect of a liver X receptor agonist

Diabetes mellitus causes endothelial dysfunction, which further exacerbates peripheral arterial disease (PAD). Improving endothelial function via reducing endothelial oxidative stress (OS) may be a promising therapy for diabetic PAD. Activation of liver X receptor (LXR) inhibits excessive OS and provides protective effects on endothelial cells in diabetic individuals. Therefore, we investigated the effects of LXR agonist treatment on diabetic PAD with a focus on modulating endothelial OS. We used a streptozotocin‐induced diabetes mouse model combined with a hindlimb ischaemia (HLI) injury to mimic diabetic PAD, which was followed by LXR agonist treatment. In our study, the LXR agonist T0901317 protected against HLI injury in diabetic mice by attenuating endothelial OS and stimulating angiogenesis. However, a deficiency in endothelial Sirtuin1 (SIRT1) largely inhibited the therapeutic effects of T0901317. Furthermore, we found that the underlying therapeutic mechanisms of T0901317 were related to SIRT1 and non‐SIRT1 signalling, and the isoform LXRβ was involved in LXR agonist‐elicited SIRT1 regulation. In conclusion, LXR agonist treatment protected against HLI injury in diabetic mice via mitigating endothelial OS and stimulating cellular viability and angiogenesis by LXRβ, which elicited both SIRT1‐mediated and non‐SIRT1‐mediated signalling pathways. Therefore, LXR agonist treatment may be a promising therapeutic strategy for diabetic PAD.

Low Expression of Sirtuin 1 in the Dairy Cows with Mild Fatty Liver Alters Hepatic Lipid Metabolism

Simple Summary

Sirtuin 1 (SIRT1), a NAD-dependent histone deacetylase, is involved in oxidative stress and lipid metabolism regulation. Limited studies exist regarding the role of SIRT1 in lipid metabolism disorder in periparturient dairy cows. This study explores the effect of hepatic steatosis on the expression of the SIRT1 gene and protein and the proteins encoded by the genes downstream to it, all of which are involved in lipid metabolism in the liver. Control cows (n = 6, parity 3.0 ± 2.0, milk production 28 ± 47 kg/d) and mild fatty liver cows (n = 6, parity 2.3 ± 1.5, milk production 20 ± 6 kg/d) were retrospectively selected based on liver triglycerides (TG) content (% wet liver). The present study indicates that low SIRT1 expression caused by hepatic steatosis promotes hepatic fatty acid synthesis and inhibits fatty acid β-oxidation. We believe that our study makes a significant contribution to the literature because it demonstrates that hepatic steatosis is associated with increased hepatic fatty acid synthesis, inhibited fatty acid β-oxidation and reduced lipid transport.

Abstract

Dairy cows usually experience negative energy balance coupled with an increased incidence of fatty liver during the periparturient period. The purpose of this study was to investigate the effect of hepatic steatosis on the expression of the sirtuin 1 (SIRT1), along with the target mRNA and protein expressions and activities related to lipid metabolism in liver tissue. Control cows (n = 6, parity 3.0 ± 2.0, milk production 28 ± 7 kg/d) and mild fatty liver cows (n = 6, parity 2.3 ± 1.5, milk production 20 ± 6 kg/d) were retrospectively selected based on liver triglycerides (TG) content (% wet liver). Compared with the control group, fatty liver cows had greater concentrations of cholesterol and TG along with the typically vacuolated appearance and greater lipid droplets in the liver. Furthermore, fatty liver cows had greater mRNA and protein abundance related to hepatic lipid synthesis proteins sterol regulatory element binding proteins (SREBP-1c), long-chain acyl-CoA synthetase (ACSL), acyl-CoA carbrolase (ACC) and fatty acid synthase (FAS) and lipid transport proteins Liver fatty acid binding protein (L-FABP), apolipoprotein E (ApoE), low density lipoprotein receptor (LDLR) and microsomal TG transfer protein (MTTP) (p < 0.05). However, they had lower mRNA and protein abundance associated with fatty acid β-oxidation proteins SIRT1, peroxisome proliferator-activated receptor co-activator-1 (PGC-1α), peroxisome proliferator–activated receptor-α (PPARα), retinoid X receptor (RXRα), acyl-CoA 1 (ACO), carnitine palmitoyltransferase 1 (CPT1), carnitine palmitoyltransferase 2 (CPT2) and long- and medium-chain 3-hydroxyacyl-CoA dehydrogenases (LCAD) (p < 0.05). Additionally, mRNA abundance and enzyme activity of enzymes copper/zinc superoxide dismutase (Cu/Zn SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and manganese superoxide dismutase (Mn SOD) decreased and mRNA and protein abundance of p45 nuclear factor-erythroid 2 (p45 NF-E2)-related factor 1 (Nrf1), mitochondrial transcription factor A (TFAM) decreased (p < 0.05). Lower enzyme activities of SIRT1, PGC-1α, Cu/Zn SOD, CAT, GSH-Px, SREBP-1c and Mn SOD (p < 0.05) and concentration of reactive oxygen species (ROS) were observed in dairy cows with fatty liver. These results demonstrate that decreased SIRT1 associated with hepatic steatosis promotes hepatic fatty acid synthesis and inhibits fatty acid β-oxidation. Hence, SIRT1 may represent a novel therapeutic target for the treatment of the fatty liver disease in dairy cows.

Inhibition of LOX-1 prevents inflammation and photoreceptor cell death in retinal degeneration

PURPOSE

To explore the expression and role of lectin-like oxidized low-density lipoprotein receptor 1 (LOX-1) in retinal degeneration.

METHODS

The retinal degeneration of BALB/c mice was induced by light exposure. BV2 cells were activated by LPS stimulation. Retinas or BV2 cells were pretreated with LOX-1 neutralizing antibody or Polyinosinic acid (PolyI) (the inhibitor of LOX-1) before light damage (LD) or LPS stimulation. LOX-1, TNF-α, IL-1β, CCL2 and NF-κB expression were detected in retinas or BV2 cells by real-time RT-PCR, western blot or ELISA. Histological analyses of retinas were performed. Photoreceptor cell death was assessed by TUNEL assay in retinas or by flow cytometry in 661W cells cultured in microglia-conditioned medium.

RESULTS

Photoreceptor cell death and elevated expression of LOX-1 were induced by LD in retinas of BALB/c mice. LOX-1 neutralizing antibody or PolyI pretreatment significantly reduced the elevated expression of LOX-1, TNF-α, IL-1β, CCL2 and p-NF-κB caused by LD in retinas. Inhibition of LOX-1 by LOX-1 neutralizing antibody or PolyI significantly reduced photoreceptor cell death induced by LD in retinas. Elevated levels of TNF-α, IL-1β and CCL2 caused by LPS were down-regulated by inhibition of LOX-1 in BV2 cells. Inhibition of LOX-1 reduces microglial neurotoxicity on photoreceptors.

CONCLUSIONS

LOX-1 expression is increased in light induced retinal degeneration, what's more, inhibition of LOX-1 prevents inflammation and photoreceptor cell death in retinal degeneration and reduces microglial neurotoxicity on photoreceptors. Therefore, LOX-1 can be used as a potential therapeutic target for such retinal degeneration diseases.

miR‑217 and miR‑543 downregulation mitigates inflammatory response and myocardial injury in children with viral myocarditis by regulating the SIRT1/AMPK/NF‑κB signaling pathway

The aim of the present study was to investigate the expression levels and roles of microRNA (miR)‑217 and miR‑543 in viral myocarditis, and to examine their underlying mechanisms. Coxsackievirus B3 (CVB3) was used to establish in vivo and in vitro models of viral myocarditis. The levels of miR‑217 and miR‑543 were detected using reverse transcription‑quantitative PCR. The association between miR‑217 and miR‑543 and sirtuin‑1 (SIRT1) was predicted and confirmed by TargetScan and dual‑luciferase reporter assay. Cell viability was detected using Cell Counting Kit‑8 assay, and cell apoptosis was measured by analyzing the expression levels of Bcl‑2 and Bax, and by flow cytometry. In addition, the synthesis of various pro‑inflammatory factors was determined by ELISA. In addition, superoxide dismutase (SOD) activity and malondialdehyde (MDA) levels were measured in cardiomyocytes following transfection and CVB infection. miR‑217 and miR‑543 were found to be highly expressed in the peripheral blood of pediatric patients with viral myocarditis, in the peripheral blood and myocardial tissues of viral myocarditis mice and in CVB3‑infected cardiomyocytes. SIRT1 was found to be a target of both miR‑217 and miR‑543, and SIRT1 expression level was downregulated in viral myocarditis. Further analysis indicated that the reduced cell viability, increased cell apoptosis, enhanced synthesis of inflammatory factors, increased MDA content and decreased SOD activity associated with myocarditis were significantly reversed after inhibition of miR‑217 or miR‑543. Importantly, the present results showed that all the effects of miR‑217 and miR‑543 inhibition on cardiomyocytes were significantly suppressed following SIRT1 knockdown. Collectively, the present data indicated that miR‑217 and miR‑543 were significantly upregulated in viral myocarditis, and downregulation of miR‑217 and miR‑543 attenuated CVB3 infection‑induced cardiomyocyte injury by targeting SIRT1. miR‑217 and miR‑543 may be potential therapeutic targets for developing novel viral myocarditis treatments in the future.

MicroRNA‑217 is involved in the progression of atherosclerosis through regulating inflammatory responses by targeting sirtuin 1

Atherosclerosis is a chronic inflammatory disease, and it is a global clinical problem. The development of new and effective therapeutic targets for atherosclerosis is necessary. A number of microRNAs (miRNAs) have been demonstrated to serve a crucial role in atherosclerosis. However, the role of miRNA (miR)-217 in atherosclerosis remains unclear. Therefore, the aim of the present study was to investigate the role and mechanism of miR-217 in atherosclerosis. The level of miR-217 was detected in the blood of patients with atherosclerosis using reverse transcription-quantitative PCR. THP-1 acute monocytic leukemia cells were treated with oxidized low-density lipoprotein (ox-LDL) to develop an atherosclerotic cell model of macrophages. The relationship between miR-217 and sirtuin 1 (SIRT1) was determined by TargetScan and dual luciferase reporter assay. Cell apoptosis was measured by flow cytometry. Production of pro-inflammatory factors and triglyceride (TG) and total cholesterol (TC) levels were also determined. The results demonstrated that miR-217 was significantly upregulated in atherosclerosis. SIRT1 was demonstrated to be a direct target of miR-217 and was downregulated in atherosclerosis. Downregulation of miR-217 significantly inhibited ox-LDL-induced TG and TC level increase, cell apoptosis and the upregulation of the pro-inflammatory factors tumor necrosis factor α, interleukin (IL)-6 and IL-1β. Additionally, the SIRT1/AMP-activated protein kinase α/NF-κB pathway was at least partially involved in modulating the effects of miR-217 inhibition on THP-1 cells treated with ox-LDL. In addition, the effects of miR-217 downregulation on ox-LDL-treated THP-1 cells were eliminated by SIRT1 silencing. In conclusion, the results of the present study indicated that miR-217 downregulation may relieve atherosclerosis through the inhibition of macrophage apoptosis and inflammatory response by targeting SIRT1.