SIRT1 mRNA Expression Research Articles

Lipopolysaccharide-induced depression is associated with estrogen receptor-α/SIRT1/NF-κB signaling pathway in old female mice

The present study aims to investigate the influence of sex/age on depressive-like behaviors in lipopolysaccharide (LPS)-challenged mice model, and explore the underlying mechanisms. Tail suspension test and forced swimming test were used to evaluate the depressive-like behaviors. SIRT1 mRNA expression was assessed by PCR. Levels of 17β-estradiol (E2), SIRT1, NF-κB, tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β) and interleukin 6 (IL-6) were detected by enzyme linked immunosorbent assay (ELISA). In the behavior tests, under the same LPS stimulation, significant depressive-like behavior was observed in young male mice but not in young female mice, however, female mice were more likely to be depressed than male mice in the old age. Moreover, we found age-related depression difference existed only in female mice. In the experiments of mechanism exploration in old female mice, E2 improved LPS-induced depressive-like behavior, and simultaneously elevated SIRT1 levels and downregulated expressions of NF-κB and inflammatory cytokines in the hippocampus and frontal cortex. Interestingly, ERα inhibition, not ERβ inhibition, abolished E2's function. Additionally, SIRT1 antagonist also reversed E2's effects on depressive-like behavior and the expressions of NF-κB and inflammatory cytokines. These results suggested that E2 could protect the old female mice from depression via E2/ERα/SIRT1/NF-κB signaling pathway. In other words, LPS-induced depression was associated with ER-α/SIRT1/NF-κB signaling pathway in old female mice. By comparing the results of mechanism exploration in old male mice and old female mice and the different expression levels of E2, SIRT1, NF-κB and inflammatory cytokines in young female mice and old female mice, we speculate that the age or gender-related depression difference may be associated with the different activation levels of the ERα/SIRT1/NF-κB signaling pathway.

Protective effects of HIIT vs. CET exercise training on high-fat-high-fructose diet-induced hyperglycemia, hyperlipidemia, and histopathology of liver in rats: regulation of SIRT1/PGC-1α

Disruption of the function of sirtuin1 (SIRT1) has been reported to link with diabetes and metabolic disorders. The aim of this study was to investigate the effect of a modified high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) or continuous endurance training (CET) program on Sirt1 and PGC-1α mRNA gene expression in hepatocytes of high-fat/high-fructose diet-induced diabetes in rats. Twenty-eight male Wistar rats (220 ± 20 g) were randomly divided into four groups of non-diabetic (NDC), diabetic control (received high fat high-fructose diet (HFHFD-DC)), CET (HFHFD-CET), and HIIT (HFHFD-HIIT). Diabetes was induced by feeding rats a high-fat (30%) high-fructose (20%) diet for 25 weeks. Following confirmed hyperglycemia, both HFHFD-CET (60–65% Vo2max) and HFHFD-HIIT (85–90% Vo2max) rats underwent treadmill exercise for 30 min, 5 days/week at 10 m/min for 8 weeks. Thereafter, blood and liver samples were obtained for biochemical studies. For histological analysis, the liver was fixed in 10% formalin, embedded in paraffin, and sectioned (5 μm thickness) for H&E staining. SIRT-1 and PGC-1α mRNA expression were measured by RT-PCR from the liver sample (frizzed sample). All data were presented as mean ± standard error mean and compared the differences by one-way analysis of variances. The alpha level was set at 0.05 (p < 0.05) for statistical difference. The results show that HIIT was more effective than CET to reduce vesicular steatosis. HIIT significantly enhanced the expression of SIRT-1 compared to the HFHFD-DC group (fold change: 1.47, p < 0.047). However, HIIT decreased PGC-1α expression compared to the HFHFD-DC group, but it was not significant (fold change: 1.32 and p < 0.247). HIIT was more effective than CET in SIRT-1 expression augmentation in high-fat, high-fructose diabetic rats which suggests a possible treatment strategy in the context of type 2 diabetes.

Role of SIRT1 in Isoflurane Conditioning-Induced Neurovascular Protection against Delayed Cerebral Ischemia Secondary to Subarachnoid Hemorrhage

We recently reported that isoflurane conditioning provided multifaceted protection against subarachnoid hemorrhage (SAH)-induced delayed cerebral ischemia (DCI), and this protection was through the upregulation of endothelial nitric oxide synthase (eNOS). SIRT1, an NAD-dependent deacetylase, was shown to be one of the critical regulators of eNOS. The aim of our current study is to examine the role of SIRT1 in isoflurane conditioning-induced neurovascular protection against SAH-induced DCI. Mice were divided into four groups: sham, SAH, or SAH with isoflurane conditioning (with and without EX-527). Experimental SAH via endovascular perforation was performed. Anesthetic conditioning was performed with isoflurane 2% for 1 h, 1 h after SAH. EX-527, a selective SIRT1 inhibitor, 10 mg/kg was injected intraperitoneally immediately after SAH in the EX-527 group. SIRT1 mRNA expression and activity levels were measured. Vasospasm, microvessel thrombosis, and neurological outcome were assessed. SIRT1 mRNA expression was downregulated, and no difference in SIRT1 activity was noted after isoflurane exposure. Isoflurane conditioning with and without EX-527 attenuated vasospasm, microvessel thrombosis and improved neurological outcomes. Our data validate our previous findings that isoflurane conditioning provides strong protection against both the macro and micro vascular deficits induced by SAH, but this protection is likely not mediated through the SIRT1 pathway.

Fasting and fasting-mimicking treatment activate SIRT1/LXRα and alleviate diabetes-induced systemic and microvascular dysfunction.

Homo sapiens evolved under conditions of intermittent food availability and prolonged fasting between meals. Periods of fasting are important for recovery from meal-induced oxidative and metabolic stress, and tissue repair. Constant high energy-density food availability in present-day society contributes to the pathogenesis of chronic diseases, including diabetes and its complications, with intermittent fasting (IF) and energy restriction shown to improve metabolic health. We have previously demonstrated that IF prevents the development of diabetic retinopathy in a mouse model of type 2 diabetes (db/db); however the mechanisms of fasting-induced health benefits and fasting-induced risks for individuals with diabetes remain largely unknown. Sirtuin 1 (SIRT1), a nutrient-sensing deacetylase, is downregulated in diabetes. In this study, the effect of SIRT1 stimulation by IF, fasting-mimicking cell culture conditions (FMC) or pharmacological treatment using SRT1720 was evaluated on systemic and retinal metabolism, systemic and retinal inflammation and vascular and bone marrow damage. The effects of IF were modelled in vivo using db/db mice and in vitro using bovine retinal endothelial cells or rat retinal neuroglial/precursor R28 cell line serum starved for 24h. mRNA expression was analysed by quantitative PCR (qPCR). SIRT1 activity was measured via histone deacetylase activity assay. NR1H3 (also known as liver X receptor alpha [LXRα]) acetylation was measured via western blot analysis. IF increased Sirt1 mRNA expression in mouse liver and retina when compared with non-fasted animals. IF also increased SIRT1 activity eightfold in mouse retina while FMC increased SIRT1 activity and expression in retinal endothelial cells when compared with control. Sirt1 expression was also increased twofold in neuronal retina progenitor cells (R28) after FMC treatment. Moreover, FMC led to SIRT1-mediated LXRα deacetylation and subsequent 2.4-fold increase in activity, as measured by increased mRNA expression of the genes encoding ATP-binding cassette transporter (Abca1 and Abcg1). These changes were reduced when retinal endothelial cells expressing a constitutively acetylated LXRα mutant were tested. Increased SIRT1/LXR/ABC-mediated cholesterol export resulted in decreased retinal endothelial cell cholesterol levels. Direct activation of SIRT1 by SRT1720 in db/db mice led to a twofold reduction of diabetes-induced inflammation in the retina and improved diabetes-induced visual function impairment, as measured by electroretinogram and optokinetic response. In the bone marrow, there was prevention of diabetes-induced myeloidosis and decreased inflammatory cytokine expression. Taken together, activation of SIRT1 signalling by IF or through pharmacological activation represents an effective therapeutic strategy that provides a mechanistic link between the advantageous effects associated with fasting regimens and prevention of microvascular and bone marrow dysfunction in diabetes.

Mechanism of microRNA-29a regulating steatosis in the human hepatocyte via targeting silent mating type information regulation 2 homolog-1

To investigate the expression of microRNA-29 a(miR-29 a) in the human steatotic hepatocyte model and the mechanism of targeting silent mating type information regulation 2 homolog-1(Sirt1)to regulate fat deposition of steatotic hepatocyte. The nonalcoholic fatty liver cell model was induced by a mixture of oleic acid and palmitic acid. After successful validation model, the expression of miR-29 a and Sirt1 was measured by PCR. The target genes of miR-29 a was predicted in biological system. MiR-29 a mimic and miR-29 a inhibitor were transfected into hepatocytes, and then established the human steatotic hepatocyte model, the result of oil red O staining and triglyceride(TG)lipid content were observed, the expression of Sirt1 mRNA and protein were detected by qRT-PCR and Western blotting, respectively. The steatosis hepatocyte model was successfully established. Compared with control group, the relative expression of miR-29 a and triglyceride increased significantly(P&lt;0. 01), while the relative expression of Sirt1 decreased significantly(P&lt;0. 01) in the model group. Sirt1 was a target gene of miR-29 a. After transfection, the lipid droplet and the deposition of fat increased obviously in miR-29 a mimic group than those in the control group. TG content in miR-29 a mimic group increased significantly(P&lt;0. 05), the expression of miR-29 a increased significantly(P&lt;0. 01), while the expression of Sirt1 mRNA decreased significantly(P&lt;0. 05), and the expression of Sirt1 protein showed a downtrend. On the contrary, after the inhibition of miR-29 a expression, the lipid droplets in miR-29 a inhibitor group were relatively reduced, the fat deposition was alleviated. The TG content was significantly decreased(P&lt;0. 05), the expression of miR-29 a in the cells was effectively inhibited(P&lt;0. 01), while the expression of Sirt1 mRNA was significantly increased(P&lt;0. 05), and Sirt1 protein was on an upward compared with the control group. The expression of miR-29 a is significantly increased in the nonalcoholic fatty liver cell model. Upregulation of miR-29 a negatively regulates the expression of Sirt1, thus promoting fat deposition of steatotic hepatocyte.

Effect of Hulled Barley Grains (Hordeum vulgare) Powder on the Gene Level Expression of PPAR-g and SIRT1 in Rats Subjected to Experimental Hyperlipidemia

Objectives: To determine the mode of hypolipidemic action of Hulled Barley Grains Powder (HBGP) on the gene level expression of PPAR-g and SIRT1 in High-Fat Diet (HFD) induced hyperlipidemic rats. Methods: The HBGP was subjected to High-Performance Liquid Chromatography (HPLC) to quantify the major phytochemicals. Male Sprague Dawley rats were fed an HFD for 14 weeks to induce hyperlipidemia. The rats in groups 1 and 2 were fed a standard diet. Group 3 and 4 rats were fed HFD for 14 weeks. From the third week onwards, Group 2 and 4 rats received 50% of HBGP mixed in the feed, in addition to 50% of the normal and HFD diets. The rats were euthanized after 14 weeks, and plasma lipids, serum levels of adiponectin and leptin were measured. The mRNA expression of PPAR-g and SIRT1were also measured. Findings: HBGP was found to contain phenolics: Ferulic acid-9.11, benzoic acid-3.58, cinnamic acid-1.191, vanillic acid-2.43, flavonoids: quercetin- 6.53, kaempferol-1.04, and myricetin-1.443 (mg/g). HFD+HBGP fed rats showed a significant decrease in blood lipids and leptin levels. Furthermore, serum adiponectin levels and mRNA expression of PPAR-g and SIRT1 were found to be quantitatively increased in HBGP co-administered rats when compared to HFD fed rats. Novelty: HBGP exhibits hypolipidemic activity by elevating the mRNA expression of PPAR-g and SIRT1. The presence of various phytochemicals such as ferulic acid, quercetin, benzoic acid, vanillic acid, myricetin, cinnamic acid, and kaempferol might be accounted for the hypolipidemic effect of HBGP. Keywords: Hyperlipidemia; HFD; HBGP; HPLC; Adiponectin; Leptin; PPAR-g ; SIRT1

Nephroprotective activity of Aframomum melegueta seeds extract against diclofenac-induced acute kidney injury: A mechanistic study

Ethnopharmacological relevanceIn Africa, Aframomum species have been traditionally used to treat illnesses such as inflammation, hypertension, diarrhea, stomachache and fever. Moreover, Aframomum melegueta seed extracts (AMSE) are used in traditional medicine to relieve stomachaches and inflammatory diseases. AimChronic administration of diclofenac (DIC) has been reported to cause acute kidney injury (AKI), which is a serious health condition. The nephroprotective effect of AMSE is yet to be elucidated. Accordingly, this study aims to investigate the phytoconstituents of standardized AMSE, evaluate its nephroprotective effects against DIC-induced AKI in rats, and elaborate its underlying molecular mechanisms. Materials and methodsThe quantitative estimation of major AMSE constituents and profiling of its secondary metabolites were conducted via RP-HPLC and LC-ESI/Triple TOF/MS, respectively. Next, DIC (50 mg/kg)-induced AKI was achieved in Sprague-Dawley rats and DIC-challenged rats were administered AMSE (100 and 200 mg/kg) orally. All treatments were administered for five consecutive days. Blood samples were collected and the sera were used for estimating creatinine, urea and, kidney injury molecule (KIM)-1 levels. Kidney specimens were histopathologically assessed and immunohistochemically examined for c-Myc expression. A portion of the kidney tissue was homogenized and examined for levels of oxidative stress markers (MDA and GSH). Heme oxygenase (HO)-1, TNF-α, IL-6, Bax, Bcl2 and caspase-3 renal levels were quantified by ELISA. Moreover, the protein expression levels of NF-ҡB p65 was quantified using Western blot analysis, whereas mRNA expression levels of AMPK, SIRT-1, nuclear factor erythroid-2-related factor (Nrf2) and STAT3 were detected using qRT-PCR in the remaining kidney tissues. ResultsStandardized AMSE was shown to primarily contain 6-gingerol, 6-shogaol and 6-paradol among the 73 compounds that were detected via LC-ESI/Triple TOF/MS including phenolic acids, hydroxyphenylalkanes, diarylheptanoids and fatty acids. Relative to DIC-intoxicated rats, AMSE modulated serum creatinine, urea, KIM-1, renal MDA, TNF-α, IL-6, Bax, and caspase-3 levels. AMSE has also improved renal tissue architecture, enhanced GSH and HO-1 levels, and upregulated renal Nrf2, AMPK, and SIRT-1 mRNA expression levels. Furthermore, AMSE suppressed NF–ҡB p65 protein and STAT3 mRNA expression, and further reduced c-Myc immunohistochemical expression in renal tissues. Overall, our findings revealed that AMSE counteracted DIC-induced AKI via its antioxidant, anti-inflammatory, and antiapoptotic activities. Moreover, AMSE activated Nrf2/HO1 and AMPK/SIRT1, and inhibited NF-ҡB/STAT3 signaling pathways. Therefore, AMSE is a promising agent for inhibiting DIC-induced nephrotoxicity.

Long non-coding RNA MCM3AP-AS1 protects chondrocytes ATDC5 and CHON-001 from IL-1β-induced inflammation via regulating miR-138-5p/SIRT1

ABSTRACT Osteoarthritis (OA) is a chronic inflammatory joint disease. Increased apoptosis of chondrocytes contributes to cartilage degradation in OA pathogenesis. The function of lncRNA MCM3AP-AS1 in regulating the viability of chondrocytes still awaits further elaboration. In this work, MCM3AP-AS1, miR-138-5p and SIRT1 mRNA expression levels in OA and normal cartilage tissues were detected by qRT-PCR. Besides, chondrocyte cell lines, CHON-001 and ATDC5 induced by interleukin-1β (IL-1β) were used to initiate the inflammatory response environment of OA. CCK-8 assay was used to examine the cell multiplication; meanwhile, transwell assay was utilized to detect migration. Western blot was adopted to determine SIRT1 expression in chondrocyte. Enzyme-linked immunosorbent assay (ELISA) was performed to evaluate inflammatory factor levels. In addition, the binding sites between MCM3AP-AS1 and miR-138-5p, miR-138-5p and 3ʹUTR of SIRT1 were validated by dual-luciferase reporter assay, RIP assay or RNA pull-down assay. It was found that MCM3AP-AS1 was declined in OA cartilage tissues, positively interrelated with SIRT1 expression while negatively correlated with miR-138-5p. MCM3AP-AS1 up-regulation enhanced the viability and migration of CHON-001 and ATDC5 cells while restraining the apoptosis and inflammatory response. Additionally, miR-138-5p overexpression counteracted the effects on chondrocytes caused by MCM3AP-AS1 overexpression. MCM3AP-AS1 could adsorb miR-138-5p, and SIRT1 was verified as a target of miR-138-5p, and SIRT1 could be up-regulated by overexpression of MCM3AP-AS1 indirectly. In conclusion, MCM3AP-AS1 has the potential to be the ‘ceRNA’ to regulate miR-138-5p and SIRT1 in chondrocytes, and to participate in the pathogenesis of OA.

Lactobacillus plantarum and Lactobacillus helveticus modulate SIRT1, Caspase3 and Bcl-2 in the testes of high-fructose-fed rats

Background and Aims: The influence of a high-fructose diet and probiotics on the male reproductive system and the testicular apoptotic pathway has been poorly documented. In this study, we aimed to investigate the influence of Lactobacillus plantarum and Lactobacillus helveticus supplementation on apoptotic factors such as sirtuin1, caspase3 and bcl-2 on the testicular tissue of high-fructose-fed rats. Methods: Fructose was given to the rats as a 20% solution in drinking water for 15 weeks. Gene expressions were established by real-time PCR. Protein levels were determined by Western blot analysis. Results: Fructose consumption did not change mRNA expression of SIRT1, but did resulted in a decreased protein level. Dietary fructose reduced bcl-2 mRNA and protein expressions, whereas no changes were observed in the gene and protein expression levels of factor caspase-3. Both Lactobacillus supplementations increased SIRT1 protein expression without changing the mRNA levels in fructose-fed rats. The supplementations with both probiotics produced a significant downregulation on caspase3 mRNA and protein levels. Bcl-2 proetin level increases with both probiotics supplementation while, mRNA level did not show difference in L.plantarum, but increased in L. helveticus supplementation. Conclusion: Treatments with L.plantarum and L.helveticus can reduce testicular apoptosis induced by dietary high-fructose in rats via suppressing caspase3 and promoting sirt1 and bcl-2 protein expressions.

Sirt1 activation negatively regulates overt apoptosis in Mtb-infected macrophage through Bax

Apoptotic pathways play an important role in Mycobacterium tuberculosis-infected macrophages. Sirt1 is a member of the deacetylase family that is known to promote apoptosis resistance in many mammalian cells. However, the apoptotic role of Sirt1 in the process of M. tuberculosis infection remains unclear. With the help of mouse macrophage samples, 129/Sv background mice, and PBMCs-derived macrophages from healthy controls and patients with tuberculosis, we have shown that M. tuberculosis infection reduced Sirt1 mRNA and protein expression, however, increased Bax mRNA and protein expression. Further, we found that resveratrol, a Sirt1 activator, inhibited M. tuberculosis-induced Bax expression. Thus, it seems that Sirt1 acts as a novel regulator of apoptosis signaling in M. tuberculosis infection via its effects on Bax. Sirt1 activation may therefore be a new candidate for the prevention and treatment of tuberculosis.

SIRT1 Antagonizes Oxidative Stress in Diabetic Vascular Complication.

Diabetic mellitus (DM) is a significant public health concern worldwide with an increased incidence of morbidity and mortality, which is particularly due to the diabetic vascular complications. Several pivotal underlying mechanisms are associated with vascular complications, including hyperglycemia, mitochondrial dysfunction, inflammation, and most importantly, oxidative stress. Oxidative stress triggers defective angiogenesis, activates pro-inflammatory pathways and causes long-lasting epigenetic changes to facilitate the development of vascular complications. Therefore, therapeutic interventions targeting oxidative stress are promising to manage diabetic vascular complications. Sirtuin1 (SIRT1), a class III histone deacetylase belonging to the sirtuin family, plays critical roles in regulating metabolism and ageing-related pathological conditions, such as vascular diseases. Growing evidence has indicated that SIRT1 acts as a sensing regulator in response to oxidative stress and attenuates vascular dysfunction via cooperating with adenosine-monophosphate-activated protein kinase (AMPK) to activate antioxidant signals through various downstream effectors, including peroxisome proliferator-activated receptor-gamma co-activator 1 (PGC-1α), forkhead transcription factors (FOXOs), and peroxisome proliferative-activated receptor α (PPARα). In addition, SIRT1 interacts with hydrogen sulfide (H2S), regulates NADPH oxidase, endothelial NO synthase, and mechanistic target of rapamycin (mTOR) to suppress oxidative stress. Furthermore, mRNA expression of sirt1 is affected by microRNAs in DM. In the current review, we summarize recent advances illustrating the importance of SIRT1 in antagonizing oxidative stress. We also discuss whether modulation of SIRT1 can serve as a therapeutic strategy to treat diabetic vascular complications.

Fasting and fasting mimetic supplementation address sirtuin expression, miRNA and microbiota composition

Background: Fasting and fasting mimetics - bioactive compounds mimicking fasting effects, are of growing interest as potential means to slow down the aging process and increase health span. Sirtuins are known as enzymes that interfere with mitochondrial energy metabolism and molecular pathways involved in longevity. Although their activation is determined as a response to stress i.e. caloric restriction. Sirtuin activating nutraceuticals are believed to mimic the effects of nutrient deprivation, thus activating signaling pathways correlated to an improved health span. In this study, we compare 5 days periodic buchinger fasting intervention with 3 months shot supplementation, a drink formula, containing secondary plant ingredients considered to activate sirtuins.Methods: We analyzed pathways in response to fasting and a sirtuins activating drink. Genetic and epigenetic biomarkers including telomere length, LINE1 methylation, and a set of mRNAs and miRNAs were assessed using qPCR analysis. Gut composition and metabolites were compared using Illumnia sequencing and mass spectrometry.Results: Fasting, but also the fasting mimetic could increase expression of FoxO1, SIRT1, and MLH1 mRNA, all genes discussed in aspects of longevity. A positive correlation between telomere length and both SIRT1, and SIRT6 was observed. Furthermore, a significant change in the gut composition was measured. Actinobacteria increased in the supplementation group, whereas after buchinger fasting a rise in the distribution of Proteobacteria could be observed. Firmicutes/Bacteroidetes ratio decreased and correlated with the body mass index (BMI).Conclusions: Our results confirm the effects of fasting on longevity associated mechanisms but also suggest that SIRTFOOD shot intervention addresses some of these effects.

Supplementation with Red Wine Extract Increases Insulin Sensitivity and Peripheral Blood Mononuclear Sirt1 Expression in Nondiabetic Humans.

The aim of this study was to investigate the effects of dietary supplementation with a nonalcoholic red wine extract (RWE), including resveratrol and polyphenols, on insulin sensitivity and Sirt1 expression in nondiabetic humans. The present study was a single-arm, open-label and prospective study. Twelve subjects received supplementation with RWE, including 19.2 mg resveratrol and 136 mg polyphenols, daily for 8 weeks. After 8 weeks, metabolic parameters, including glucose/lipid metabolism and inflammatory markers, were evaluated. mRNA expression of Sirt1 was evaluated in isolated peripheral blood mononuclear cells (PBMNCs). Additionally, Sirt1 and phosphorylated AMP-activated kinase (p-AMPK) expression were evaluated in cultured human monocytes (THP-1 cells). Supplementation with RWE for 8 weeks decreased the homeostasis model assessment for insulin resistance (HOMA-IR), which indicates an increase in insulin sensitivity. Serum low-density lipoprotein-cholesterol (LDL-C), triglyceride (TG) and interleukin-6 (IL-6) were significantly decreased by RWE supplementation for 8 weeks. Additionally, Sirt1 mRNA expression in isolated PBMNCs was significantly increased after 8 weeks of RWE supplementation. Moreover, the rate of increase in Sirt1 expression was positively correlated with the rate of change in HOMA-IR. The administration of RWE increased Sirt1 and p-AMPK expression in cultured THP-1 cells. Supplementation with RWE improved metabolism, such as insulin sensitivity, lipid profile and inflammation, in humans. Additionally, RWE supplementation induced an increase in Sirt1 expression in PBMNCs, which may be associated with an improvement in insulin sensitivity.

SIRT1 mediates hypoxic preconditioning induced attenuation of neurovascular dysfunction following subarachnoid hemorrhage

Background and purposeVasospasm and delayed cerebral ischemia (DCI) contribute significantly to the morbidity/mortality associated with aneurysmal subarachnoid hemorrhage (SAH). While considerable research effort has focused on preventing or reversing vasospasm, SAH-induced brain injury occurs in response to a multitude of concomitantly acting pathophysiologic mechanisms. In this regard, the pleiotropic epigenetic responses to conditioning-based therapeutics may provide an ideal SAH therapeutic strategy. We previously documented the ability of hypoxic preconditioning (PC) to attenuate vasospasm and neurological deficits after SAH, in a manner that depends on the activity of endothelial nitric oxide synthase. The present study was undertaken to elucidate whether the NAD-dependent protein deacetylase sirtuin isoform SIRT1 is an upstream mediator of hypoxic PC-induced protection, and to assess the efficacy of the SIRT1-activating polyphenol Resveratrol as a pharmacologic preconditioning therapy. MethodsWild-type C57BL/6J mice were utilized in the study and subjected to normoxia or hypoxic PC. Surgical procedures included induction of SAH via endovascular perforation or sham surgery. Multiple endpoints were assessed including cerebral vasospasm, neurobehavioral deficits, SIRT1 expression via quantitative real-time PCR for mRNA, and western blot for protein quantification. Pharmacological agents utilized in the study include EX-527 (SIRT1 inhibitor), and Resveratrol (SIRT1 activator). ResultsHypoxic PC leads to rapid and sustained increase in cerebral SIRT1 mRNA and protein expression. SIRT1 inhibition blocks the protective effects of hypoxic PC on vasospasm and neurological deficits. Resveratrol pretreatment dose-dependently abrogates vasospasm and attenuates neurological deficits following SAH – beneficial effects that were similarly blocked by pharmacologic inhibition of SIRT1. ConclusionSIRT1 mediates hypoxic preconditioning-induced protection against neurovascular dysfunction after SAH. Resveratrol mimics this neurovascular protection, at least in part, via SIRT1. Activation of SIRT1 is a promising, novel, pleiotropic therapeutic strategy to combat DCI after SAH.

Atorvastatin promotes bone formation in aged apoE\u2013/\u2013 mice through the Sirt1\u2013Runx2 axis

BackgroundStatins are the most widely used drugs in elderly patients; the most common clinical application of statins is in aged hyperlipemia patients. There are few studies on the effects and mechanisms of statins on bone in elderly mice with hyperlipemia. The study is to examine the effects of atorvastatin on bone phenotypes and metabolism in aged apolipoprotein E-deficient (apoE–/–) mice, and the possible mechanisms involved in these changes.MethodsTwenty-four 60-week-old apoE–/– mice were randomly allocated to two groups. Twelve mice were orally gavaged with atorvastatin (10 mg/kg body weight/day) for 12 weeks; the others served as the control group. Bone mass and skeletal microarchitecture were determined using micro-CT. Bone metabolism was assessed by serum analyses, qRT-PCR, and Western blot. Bone marrow-derived mesenchymal stem cells (BMSCs) from apoE–/– mice were differentiated into osteoblasts and treated with atorvastatin and silent information regulator 1 (Sirt1) inhibitor EX-527.ResultsThe results showed that long-term administration of atorvastatin increases bone mass and improves bone microarchitecture in trabecular bone but not in cortical bone. Furthermore, the serum bone formation marker osteocalcin (OCN) was ameliorated by atorvastatin, whereas the bone resorption marker tartrate-resistant acid phosphatase 5b (Trap5b) did not appear obviously changes after the treatment of atorvastatin. The mRNA expression of Sirt1, runt-related transcription factor 2 (Runx2), alkaline phosphatase (ALP), and OCN in bone tissue were increased after atorvastatin administration. Western blot showed same trend in Sirt1 and Runx2. The in vitro study showed that when BMSCs from apoE–/– mice were pretreated with EX527, the higher expression of Runx2, ALP, and OCN activated by atorvastatin decreased significantly or showed no difference compared with the control. The protein expression of Runx2 showed same trend.ConclusionsAccordingly, the current study validates the hypothesis that atorvastatin can increase bone mass and promote osteogenesis in aged apoE−/− mice by regulating the Sirt1–Runx2 axis.

A Comprehensive Analysis of the Effect of SIRT1 Variation on the Risk of Schizophrenia and Depressive Symptoms.

Depressive symptoms could be considered a mutual manifestation of major depressive disorder and schizophrenia. Rs3758391 is a functional locus of Sirtuin (SIRT1) involving depression etiology. In this study, we hypothesized that the SIRT1 SNP rs3758391 might be a hazard for schizophrenia pathogenesis, especially related to the appearance of depressive symptoms. We recruited 723 healthy controls and 715 schizophrenia patients, the occurrence of psychotic and depressive symptoms was evaluated by Calgary Depression Scale (CDSS) and PANSS. Meanwhile, qt-PCR was used to detect the mRNA levels of SIRT1 in peripheral blood of 197 olanzapine monotherapy schizophrenia patients. 45.6% of schizophrenia patients had depressive symptoms. In the patient group, mRNA levels of patients with depressive symptoms were significantly lower than those without depressive symptoms (P < 0.01). CDSS scores of schizophrenia patients with different rs3758391 genotypes were significantly different (P < 0.01). Post hoc comparisons indicated that the CDSS scores of rs3758391 C/C and C/T carriers were higher than those of T/T carriers (Ps < 0.01). In the occipital cortex, our eQTL analysis showed that there was a clear correlation between rs3758391 and the SIRT1 mRNA levels. Our preliminary findings provide suggestive evidence that SIRT1 makes schizophrenia patients more prone to depressive symptoms. This SNP might be a biomarker of depression in schizophrenia.

Expression of Sirtuin 1 in visceral adipose tissue in Tibetan mini-pigs with obesity and insulin resistance induced by high fat/cholesterol diet

To investigate the role of Sirt1 in visceral adipose tissue in Tibetan mini-pigs with obesity and insulin resistance induced by high fat/cholesterol diet. Twelve male Tibetan mini-pigs were divided into 2 groups randomly: normal control (NC) group, high-fat/cholesterol (HFC) diet group, 6 in each group. After 16 weeks of modeling, fasting body weight and body mass index (BMI) were measured. Total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) were measured in anterior venous blood, and atherosclerosis index (AI) was calculated. Meanwhile, intravenous glucose tolerance test was conducted to observe the changes of blood glucose and insulin, and the area under the curve (AUC) was calculated. After euthanasia, visceral fat rate was detected, and visceral fat tissue was taken for histopathological observation and fat cell diameter analysis. RT-PCR was used to observe the mRNA expression levels of Sirtuin1 (Sirt1), insulin-like growth factor-1 (IGF-1), glucose transporter 4 (GLUT4), peroxisome proliferator-activated receptor γ (PPARγ), peroxisome proliferator-activated receptor γ-assisted activator 1α (PGC-1α), forkhead box protein O1 (FoxO1), lipolysis-related gene hormone-sensitive lipase (HSL), and fat synthesis-related gene fatty acid synthase (FASN)changes in adipose tissue. Compared with the NC group, the body weight, BMI, TC, LDL-C, HDL-C, AI and visceral fat rate were significantly increased after 16 weeks of high-fat/cholesterol induction in Tibetan mini-pigs(P＜0.05,P＜0.01). Meanwhile, the glucose tolerance curve was significantly delayed and the area under the curve of blood glucose and insulin was significantly increased (P＜0.05). HE pathological observation and quantitative analysis showed that fat cells were hypertrophy and the average cell diameter was increased significantly (P＜0.01). In addition, the mRNA expression levels of Sirt1,PGC-1α, GLUT4, and HSL were all decreased in varying degrees in adipose tissue, among which the mRNA expressions of Sirt1 and HSL were significantly decreased (P＜0.05), while the mRNA expressions of FOXO1, IGF-1, PPARγ, and FASN were significantly increased (P＜0.05, P＜0.01). Tibetan mini-pigs were induced by high fat/cholesterol diet to form obesity model with phenotypic characteristics such as lipid disorder and insulin resistance, whereas Sirt1 plays a key role in visceral fat deposition and insulin sensitivity reduction in obese Tibetan mini-pigs.

Acute lung injury inhibition by juglone in LPS induced sepsis mouse model involves Sirt1 activation

Purpose: To investigate the effect of juglone on LPS induced lung injury in a mouse model and in TC 1cell line.Methods: Edema formation in lungs were measured by determination of lung wet/dry weight. Expressions of various proteins were assessed by western blot assay, while Sirt1 level was assessed using immunohistochemistry. Mice were randomly assigned to nine groups of 10 mice each: normal control, untreated and seven juglone treatment groups. Acute lung injury was induced in mice by injecting LPS (10 mg/kg) via intraperitoneal route (ip). The treatment groups were given 10, 20, 30, 40, 50, 60 and 100 μM of juglone, ip, respectively.Results: The levels of MMP-9, IL-6, IL-1β and iNOS were significantly higher in acute lung injury induced mice compared than the control group (p &lt; 0.05). Treatment of the mice with juglone significantly decreased LPS-induced up-regulation of inflammatory cytokines in a dose-dependentmanner. The production of inflammatory cytokines was almost completely inhibited in the mice treated with 100 mg/kg dose of juglone, while treatment of the LPS-stimulated TC 1 cells with juglone upregulated the expression of Sirt1 mRNA. Down-regulation of Sirt1 expression by siRNA inhibited the effect of juglone on LPS-induced increase in inflammatory cytokine production.Conclusion: Juglone prevents lung injury in mice via up-regulation of Sirt1 expression. Therefore, juglone might be useful for the development of a treatment strategy for lung injury.&#x0D; Keywords: Inflammatory, Sirtuin, Edema, Cytokines, Lung injury, TC 1 lung alveolar epithelial cells, Sirt1

MRNA expression of ageing-associated genes in calorie reduction is subject to donor variability and can be induced by calorie restriction mimetics.

Finding ways to a healthier ageing are increasingly becoming the focus of geriatric research. One way to accomplish this could be calorie restriction, as this is known to positively influence the ageing of model organisms. The aim of this study was to investigate the influence of calorie reduction (F. X. Mayr therapy) and of the calorie restriction mimetics resveratrol and spermidine on the expression of ageing-associated genes. mRNA expression in peripheral blood mononuclear cells (PBMCs) of 18 participants taking part in an F. X. Mayr therapy was analysed. The PBMCs of one additional participant were treated ex vivo with spermidine or resveratrol. mRNA expression of SIRT1, SIRT3, FOXO3 and SOD2 was determined for these two calorie restriction mimetics. For the F. X. Mayr therapy samples, mRNA of XPA was analysed additionally. mRNA expression of the ageing-associated genes showed a distinct donor variation during F. X. Mayr therapy, with a significant increase in mRNA expression of SIRT1. Expression of XPA was similar to SIRT1, with a significant correlation at the last time point tested. Spermidine treatment of PBMCs resulted in a significantly increased expression of all genes tested, whereas resveratrol treatment caused a significant increase of SIRT3, FOXO3 and SOD2 mRNA expression. By increasing SIRT1 and XPA mRNA expression, calorie reduction in the form of F. X. Mayr therapy could contribute to a healthier ageing; however, the donor variability observed showed that not everyone benefited from this. Calorie restriction mimetics may be an option for promote healthier ageing for those who do not benefit from calorie reduction.

Dietary β-hydroxy-β-methylbutyrate improves intestinal function in weaned piglets after lipopolysaccharide challenge.

The aim of this study was to explore the effects of β-hydroxy-β-methylbutyrate (HMB) on intestinal function of lipopolysaccharide (LPS)-challenged piglets. Forty weaned piglets were used in a 2 × 2 factorial design. The major factors were challenge (saline or LPS) and diet (basal diet or 0.6% HMB-Ca diet). After 15 d of treatment with LPS or HMB, blood and intestine samples were obtained. The results showed that in LPS-injected pigs, HMB supplementation significantly increased jejunal villus height and ileal villus height-to-crypt depth ratio and decreased ileal crypt depth (P < 0.05). HMB also improved intestinal function indicated by elevated activities of intestinal mucosal disaccharidase and tricarboxylic acid cycle key enzymes. Furthermore, HMB significantly downregulated mRNA expression of Sirt1 in jejunum and mRNA expression of AMPKα1 and Sirt1 in ileum (P < 0.05), with a concurrent decrease of AMPKα phosphorylation in jejunum and ileum. Microbiota analysis indicated that HMB supplementation significantly increased α-diversity and affected relative abundances of Romboutsia and Sarcina at the genus level, accompanied by increased concentrations of all short-chain fatty acids except propionate in the terminate ileum of LPS-injected piglets. Dietary HMB supplementation could improve intestinal integrity, function, microbiota communities, and short-chain fatty acid concentrations in LPS-challenged piglets, suggesting its potential usage as a feed additive in weaned piglets to alleviate intestinal dysfunction triggered by immune stress.