Promoting SIRT1 Expression Research Articles

Discovery of SIRT1-Activating Hydrogen Sulfide Donating Derivatives for Efficient Resistant of Myocardial Ischemic Injury.

Activating SIRT1 or promoting SIRT1 expression are both protective against myocardial ischemia. Combining these approaches would be an effective strategy for treating ischemic heart disease. Herein, we identified lead compounds with SIRT1 activation activity through screening the natural product library, and five series of H2S donating derivatives were designed and synthesized. Among them, compound 17 exerted an effective cardioprotective effect in vitro and in vivo. The addition of H2S scavenger attenuated the protective activity, emphasizing the critical involvement of H2S in the myocardial ischemia process. Interestingly, 17 exhibited stronger direct SIRT1 activative ability and induced higher SIRT1 expression capability compared to the lead. Furthermore, 17 attenuates oxidative stress-induced cardiomyocytes apoptosis by activating the SIRT1-PGC1α signaling pathway. Our study validated the promising potential of activating SIRT1 and promoting SIRT1 expression through H2S to improve cardiomyocytes function, providing novel insights into the protective mechanisms during the progression of ischemic heart disease.

Protective effect of naringin against radiation-induced heart disease in rats via Sirt1/NF-κB signaling pathway and endoplasmic reticulum stress.

This study was designed to explore the protective effect and mechanism of naringin (NG) on radiation-induced heart disease (RIHD) in rats. Rats were divided into four x-ray (XR) irradiation groups with different absorbed doses (0/10/15/20 Gy), or into three groups (control, XR, and XR + NG groups). Subsequently, the ultrasonic diagnostic apparatus was adopted to assess and compare the left ventricular ejection fraction (LVEF), left ventricular fractional shortening (LVFS), left ventricular internal diameter at end diastole (LVIDd), and left ventricular internal diameter at end systole (LVIDs) in rats. Hematoxylin-eosin (H&E) staining and Masson staining were applied to detect the pathological damage and fibrosis of heart tissue. Western blot was used to measure the expression levels of myocardial fibrosis-related proteins, endoplasmic reticulum stress-related proteins, and Sirt1 (silent information regulator 1)/NF-κB (nuclear factor kappa-B) signaling pathway-related proteins in cardiac tissues. Additionally, enzyme-linked immunosorbent assay was utilized to detect the activities of pro-inflammatory cytokines, malondialdehyde (MDA), superoxide dismutase (SOD), and catalase (CAT) in cardiac tissue. The results showed that NG treatment significantly attenuated the 20 Gy XR-induced decline of LVEF and LVFS and the elevation of LVIDs. Cardiac tissue damage and fibrosis caused by 20 Gy XR were significant improved after NG treatment. Meanwhile, in rats irradiated by XR, marked downregulation was identified in the expressions of fibrosis-related proteins (Col I, collagen type I; α-SMA, α-smooth muscle actin; and TGF-β1, transforming growth factor-beta 1) and endoplasmic reticulum stress-related proteins (GRP78, glucose regulatory protein 78; CHOP, C/EBP homologous protein; ATF6, activating transcription factor 6; and caspase 12) after NG treatment. Moreover, NG treatment also inhibited the production of pro-inflammatory cytokines [interleukin-6, interleukin-1β, and monocyte chemoattractant protein-1 (MCP-1)], reduced the expression of MDA, and promoted the activities of SOD and CAT. Also, NG treatment promoted Sirt1 expression and inhibited p65 phosphorylation. Collectively, XR irradiation induced cardiac injury in rats in a dose-dependent manner. NG could improve the cardiac injury induced by XR irradiation by inhibiting endoplasmic reticulum stress and activating Sirt1/NF-κB signaling pathway.

Didymin alleviates metabolic dysfunction-associated fatty liver disease (MAFLD) via the stimulation of Sirt1-mediated lipophagy and mitochondrial biogenesis

BackgroundMetabolic dysfunction-associated fatty liver disease (MAFLD) is one of the most prevalent metabolic syndromes worldwide. However, no approved pharmacological treatments are available for MAFLD. Chenpi, one kind of dried peel of citrus fruits, has traditionally been utilized as a medicinal herb for liver diseases. Didymin is a newly identified oral bioactive dietary flavonoid glycoside derived from Chenpi. In this study, we investigated the therapeutic potential of Didymin as an anti-MAFLD drug and elucidated its underlying mechanisms.MethodsHigh-fat diet (HFD)-induced MAFLD mice and alpha mouse liver 12 (AML12) cells were utilized to evaluate the effects and mechanisms of Didymin in the treatment of MAFLD. Liver weight, serum biochemical parameters, and liver morphology were examined to demonstrate the therapeutic efficacy of Didymin in MAFLD treatment. RNA-seq analysis was performed to identify potential pathways that could be affected by Didymin. The impact of Didymin on Sirt1 was corroborated through western blot, molecular docking analysis, microscale thermophoresis (MST), and deacetylase activity assay. Then, a Sirt1 inhibitor (EX-527) was utilized to confirm that Didymin alleviates MAFLD via Sirt1. Western blot and additional assays were used to investigate the underlying mechanisms.ResultsOur results suggested that Didymin may possess therapeutic potential against MAFLD in vitro and in vivo. By promoting Sirt1 expression as well as directly binding to and activating Sirt1, Didymin triggers downstream pathways that enhance mitochondrial biogenesis and function while reducing apoptosis and enhancing lipophagy.ConclusionsThese suggest that Didymin could be a promising medication for MAFLD treatment. Furthermore, its therapeutic effects are mediated by Sirt1.

Cardamonin protects against iron overload induced arthritis by attenuating ROS production and NLRP3 inflammasome activation via the SIRT1/p38MAPK signaling pathway

Iron homeostasis plays an essential role in joint health, while iron overload can cause damage and death of cartilage cells. Cardamonin (CAR) is a substance found in the fruit of the chasteberry plant and has anti-inflammatory and anti-tumor activities. We first administered iron dextran (500 mg/kg) intraperitoneally to establish an iron overload mouse model and surgically induced osteoarthritis. The extent of OA and iron deposition were assessed using Micro-ct, Safranin-O/fast green staining, H&E staining, and Prussian Blue 10 weeks later. We administered primary chondrocytes with Ferric Ammonium Citrate (FAC) to evaluate the chondrocyte changes. Chondrocytes were identified in vitro by toluidine blue staining, and chondrocyte viability was evaluated by CCK-8. The rate of apoptosis was determined by Annexin V-FITC/PI assay. The mechanism of action of CAR was verified by adding the SIRT1 inhibitor EX527, and the expression of SIRT1 and MAPK signaling pathways was detected by Western blot. Iron overload also promoted chondrocyte apoptosis, a process that was reversed by CAR. In addition, CAR reduced NLRP3 inflammasome production via the SIRT1-MAPK pathway, and the SIRT1 inhibitor EX527 inhibited the treatment of OA by CAR.CAR inhibited cartilage degeneration induced by iron overload both in vivo and in vitro. Besides, our study showed that iron overload not only inhibited type II collagen expression but also induced MMP expression by catalyzing the generation of NLRP3 inflammasome. Our results suggest that CAR can treat KOA by promoting SIRT1 expression and inhibiting p38MAPK pathway expression to reduce the production of NLRP3 inflammasome vesicles.

Ubiquitin-specific protease 8 regulates cognitive dysfunction of mice with sepsis-associated encephalopathy through SIRT1 deubiquitination.

Sepsis-associated encephalopathy (SAE) is the most severe complication of sepsis. Ubiquitin-specific protease 8 (USP8) could improve cognitive and motor disorders in SAE. This study explored the mechanism of USP8 in SAE mice to provide new therapeutic targets for SAE. C57BL/6 mice were selected to establish SAE models by caecal ligation and puncture (CLP) and injected with lentivirus overexpressing USP8 one week before SAE modeling. Mouse weight changes were monitored, cognitive and learning abilities were tested by the Morris water maze test, behaviors were evaluated by open-field tests, and pathological changes in brain tissue were analyzed by H&E staining. Levels of USP8, TNF-α, IL-1β, IL-6, and IL-10, and SOD, GSH-Px activities, and MDA levels were detected by Western blot, ELISA, and kits. Co-immunoprecipitation assay verified the interaction between USP8 and SIRT1 and SIRT1 ubiquitination level. In CLP mice, the body weight, cognitive function, and learning ability were decreased, along with motor disorder, abnormal morphological structure of neurons, and obvious inflammatory infiltration. USP8 protein in brain tissue was decreased, the levels of TNF-α, IL-1β, and IL-6 were increased, IL-10 was decreased, SOD and GSH-Px activities were decreased, and MDA level was increased. USP8 treatment improved cognitive dysfunction and inhibited inflammation and oxidative stress in CLP mice. USP8 promoted SIRT1 expression by direct deubiquitination. SIRT1 knockdown partially reversed the regulation of USP8 on SAE mice. USP8 can directly deubiquitinate SIRT1 and inhibit inflammatory reactions and oxidative stress, thus improving cognitive dysfunction in SAE mice.

Exosomes from circ-Astn1-modified adipose-derived mesenchymal stem cells enhance wound healing through miR-138-5p/SIRT1/FOXO1 axis regulation

Wound healing impairment is a dysfunction induced by hyperglycemia and its effect on endothelial precursor cells (EPCs) in type 2 diabetes mellitus. There is increasing evidence showing that exosomes (Exos) derived from adipose-derived mesenchymal stem cells (ADSCs) exhibit the potential to improve endothelial cell function along with wound healing. However, the potential therapeutic mechanism by which ADSC Exos contribute to wound healing in diabetic mice remains unclear.To reveal the potential therapeutic mechanism of ADSC Exos in wound healing in diabetic mice.Exos from ADSCs and fibroblasts were used for high-throughput RNA sequencing (RNA-Seq). ADSC-Exo-mediated healing of full-thickness skin wounds in a diabetic mouse model was investigated. We employed EPCs to investigate the therapeutic function of Exos in cell damage and dysfunction caused by high glucose (HG). We utilized a luciferase reporter (LR) assay to analyze interactions among circular RNA astrotactin 1 (circ-Astn1), sirtuin (SIRT) and miR-138-5p. A diabetic mouse model was used to verify the therapeutic effect of circ-Astn1 on Exo-mediated wound healing.High-throughput RNA-Seq analysis showed that circ-Astn1 expression was increased in ADSC Exos compared with Exos from fibroblasts. Exos containing high concentrations of circ-Astn1 had enhanced therapeutic effects in restoring EPC function under HG conditions by promoting SIRT1 expression. Circ-Astn1 expression enhanced SIRT1 expression through miR-138-5p adsorption, which was validated by the LR assay along with bioinformatics analyses. Exos containing high concentrations of circ-Astn1 had better therapeutic effects on wound healing in vivo compared to wild-type ADSC Exos. Immunofluorescence and immunohistochemical investigations suggested that circ-Astn1 enhanced angiopoiesis through Exo treatment of wounded skin as well as by suppressing apoptosis through promotion of SIRT1 and decreased forkhead box O1 expression.Circ-Astn1 promotes the therapeutic effect of ADSC-Exos and thus improves wound healing in diabetes via miR-138-5p absorption and SIRT1 upregulation. Based on our data, we advocate targeting the circ-Astn1/miR-138-5p/SIRT1 axis as a potential therapeutic option for the treatment of diabetic ulcers.

Lin28A Reduced Sevoflurane-Induced Nerve Injury and Cognitive Dysfunction by Inhibiting Tau Acetylation and Phosphorylation via Activating SIRT1 in Elderly Rats.

Sevoflurane (Sev) might cause neurotoxicity in elderly rats. However, the role of Lin28A in Sev-induced neurotoxicity remains unclear in elderly rats. In this study, elderly rats were used to construct an Sev-induced nerve injury model. Learning and memory abilities were assessed by Morris water maze (MWM) trainings; pathological alterations in hippocampal region were assessed by HE staining; neuronal apoptosis was assessed by TUNEL; related protein expression was analyzed by immunofluorescence, immunohistochemistry, and Western blotting. Results of this study showed that Sev treatment caused nerve injury and cognitive dysfunction in elderly rats, with increased neuronal apoptosis and decreased Lin28A levels. Pathological impairment and learning and memory abilities of elderly rats were significantly improved after forced overexpression of Lin28A using AAV, accompanied by decreased expression of CD68, Iba-1, and GFAP. TUNEL analysis showed that Lin28A overexpression significantly reversed Sev-induced neuronal apoptosis. Further mechanistic analysis showed that Lin28A significantly promoted SIRT1 expression, which further reversed Sev-induced Tau acetylation at lysine 280 and 686 and Tau hyperphosphorylation, thereby alleviating nerve injury and cognitive dysfunction in elderly rats. The introduction of SIRT1 inhibitor EX527 further confirmed the involvement of SIRT1 in the regulation of Lin28A in elderly rats. In conclusion, our findings demonstrated that Lin28A reduced sevoflurane-induced nerve injury and cognitive dysfunction by inhibiting Tau acetylation and phosphorylation via activating SIRT1 in elderly rats.

Ligustrazine prevents coronary microcirculation dysfunction in rats via suppression of miR-34a-5p and promotion of Sirt1

IntroductionThe coronary microembolization contributes to coronary microvascular dysfunction (CMD), in which miR-34a-5p may play a critical role. Ligustrazine has been reported to improve CMD. The present study was designed to discuss the role of miR-34a-5p/Sirt1 pathway in CMD and explore the underlying mechanism of ligustrazine. MethodsCoronary microembolization (CME) was induced by left ventricle injection of sodium laurate in rats. CME formation and cardiac function were examined by HE staining and hemodynamic tests to evaluate CMD. The expressions of miR-34a-5p, Sirt1 and the downstream proteins were detected by RT-qPCR and western blot. Dual-luciferase reporter (DLR) assay was performed to confirm the connection between miR-34a-5p and Sirt1. The blood markers of endothelial dysfunction, platelet activation and inflammation were examined with ELISA. ResultsOvert CME and cardiac dysfunction as well as up-regulated miR-34a-5p and down-regulated Sirt1 were observed in CME rats. Overexpressing miR-34a-5p aggravated while silencing miR-34a-5p inhibited CME formation. DLR assay confirmed that miR-34a-5p directly inhibited Sirt1 mRNA expression. Ligustrazine pretreatment suppressed miR-34a-5p and promoted Sirt1 expression, which alleviated endothelial dysfunction, inhibited platelet activation and inflammation, and in turn reduced CME. Overexpressing miR-34a-5p diminished the positive effects of ligustrazine; while after silencing miR-34a-5p, ligustrazine failed to further promote Sirt1 expression and inhibit CME formation. ConclusionMiR-34a-5p contributes to CMD by inhibiting Sirt1 expression. Ligustrazine exerts endothelial-protective, anti-platelet and anti-inflammatory effects to prevent CMD via suppressing miR-34a-5p and promoting Sirt1.

Ameliorative Potential of Resveratrol in Dry Eye Disease by Restoring Mitochondrial Function.

Methods The mitochondrial dysfunction of HCE-2 human corneal epithelial cells was induced by high osmotic pressure exposure and treated with resveratrol (50 μM). Western blotting was used to detect the expression of the antioxidant proteins SOD2, GPx, and SIRT1, and flow cytometry was used to detect cell apoptosis and ROS production. The DED mouse model was induced by 0.2% benzalkonium chloride (BAC) and treated with resveratrol. The tear yield was measured by the phenol cotton thread test, the density of cup cells in the conjunctiva was measured by periodic acid-Schiff (PAS) staining, and the expression levels of SIRT1, GPx, and SOD2 in lacrimal glands were detected by Western blotting. Results In hypertonic conditions, the apoptosis of HCE-2 cells increased, the expression of the antioxidant proteins SOD2 and GPx decreased, ROS production increased, and the expression of SIRT1 protein, an essential regulator of mitochondrial function, was downregulated. Treatment with resveratrol reversed the mitochondrial dysfunction mediated by high osmotic pressure. In the DED mouse model, resveratrol treatment promoted tear production and goblet cell number in DED mice, decreased corneal fluorescein staining, upregulated SIRT1 expression, and induced SOD2 and GPx expression in DED mice. Conclusion Resveratrol alleviates mitochondrial dysfunction by promoting SIRT1 expression, thus reducing ocular surface injury in mice with dry eye. This study suggests a new path against DED.

Autophagy-Sirtuin1(SIRT1) Alleviated the Coronary Atherosclerosis (AS)in Mice through Regulating the Proliferation and Migration of Endothelial Progenitor Cells (EPCs) via wnt/β-catenin/GSK3β Signaling Pathway.

SIRT1 was associated with AS risk and EPCs were reported to participate in the endothelial repair in Coronary Atherosclerosis (CAS). In this study, we explored the role of SIRT1 in AS mice and also its modulation in EPCs. ApoE-/-mice were fed on high-fat and high-glucose diet to establish the AS animal model with the normally-raised C57BL/6 mice as a control group. SIRT1 activator, SRT 2104 was injected intravenously into 5 ApoE-/-mice and its inhibitor Nicotinamide was injected in tail in another 5 ApoE-/-mice. Weight changes were recorded. Blood samples were taken from posterior orbital venous plexus and were detected by automatic biochemical analyzer. HE staining displayed the pathological conditions while Immunohistochemistry (IHC) evaluated the CD34+/VEGFR2+ relative density in the aorta tissues. EPCs were isolated from bone marrow and verified using immunofluorescence staining (IFS). The modulatory mechanism of SIRT1 in EPCs were studied by using RT-PCR, MTT, Western Blot and colony formation, scratch methods. SIRT1 activator negatively regulated the weight and TC, TG and LDL levels, alleviated the lesion conditions and decreased the CD34+/VEGFR2+ density compared to the AS control. In vitro, SIRT1 activator promoted the proliferation and migration of EPCs and activated wnt/β-catenin/GSK3β signaling pathway. SIRT1 activator also inhibited the autophagy biomarkers ATG1 and LC3II. Furthermore, inhibitor of autophagy promoted SIRT1 expression and induced EPC proliferation, migration and activated wnt/β-catenin/GSK3β pathway. The suppression of the wnt/β-catenin/GSK3β pathway inhibited SIRT1 expression in EPCs, attenuated the proliferation and migration and promoted autophagy of EPCs. SIRT1 activation might be protective in AS mice through autophagy inhibition in EPCs via wnt/β-catenin/GSK3β signaling pathway.

LncRNA XIST restrains the activation of Müller cells and inflammation in diabetic retinopathy via stabilizing SIRT1

Background Recent studies have provided strong evidence that lncRNAs play a functional regulatory role in diabetic retinopathy (DR). The purpose of this study was to investigate the effect of long non-coding RNA (lncRNA) X-inactive specific transcript (XIST) in DR. Methods A DR mouse model was established by intraperitoneal injection of streptozotocin (STZ), and then the mouse retinal Müller cells (mMCs) were isolated from retina tissues of mice. Human retinal Müller cell line (HMCs) and mMCs and were treated with high glucose (HG) to simulate an in vitro DR model. XIST expression was detected by qRT-PCR. Next, XIST overexpression was performed in mMCs and HMCs to examine its effect on the activation of Müller cells and production of pro-inflammatory cytokines. Subsequently, the interaction between XIST and SIRT1 was verified, and the ubiquitination level of SIRT1 as well as the stability of SIRT1 protein were assessed. Results XIST was down-regulated in retinal tissues of DR mice and HG-induced HMCs. Overexpression of XIST inhibited HG-induced activation of mMCs and HMCs, and reduced the production of pro-inflammatory cytokines. XIST promoted SIRT1 expression via interacting with SIRT1 and inhibiting the ubiquitination of SIRT1. Furthermore, SIRT1 silencing partly abrogated the effect of XIST overexpression on the activation of mMCs and HMCs as well as the production of pro-inflammatory cytokines induced by HG. Conclusion We concluded that XIST restrained the activation of Müller cells and the production of pro-inflammatory cytokines via stabilizing SIRT1.

Effect of Silencing Information Regulator on Islet β Cells in High Glucose Environment Through Regulation of Phosphatidylinositol 3 Kinase (PI3K)/Protein Kinase B (AKT)/Nuclear Factor-κ-Gene Binding Pathway

Islet β-cell regeneration is beneficial for treating diabetic patients. Silencing information regulator (SIRT1) has a regulatory role in endocrine diseases. However, SIRT1’s role in islet β cells remains unclear. MIN6 cells were cultured and assigned into control group, high glucose group, and SIRT1 group (treated with SIRT1 agonist, Resveratrol) followed by analysis of SIRT1 expression by Real time PCR and ELISA, cell proliferation by MTT assay, apoptosis activity by Caspase3 activity kit, secretion of TNF-α and IL-2 by ELISA, insulin secretion, ROS and SOD generation and expression of PI3K/Akt/NF-κB signaling by Western blot. SIRT1 mRNA was decreased in high glucose environment and its secretion in cell supernatant was reduced, with inhibited cell proliferation, increased Caspase3 activity and secretion of TNF-α and IL-2, decreased insulin secretion and SOD activity, increased ROS content, pAKT phosphorylation and NF-κB expression. Resveratrol significantly promoted SIRT1 expression and cell proliferation, decreased Caspase3 activity and secretion of TNF-α and IL-2, increased insulin secretion and SOD activity, as well as decreased ROS content, pAKT phosphorylation and NF-κB expression (P <0.05). SIRT1 is decreased in high glucose environment, and SIRT1 expression can inhibit islet cell apoptosis, inhibit oxidative stress and inflammation, and promote islet cell proliferation and insulin secretion by regulating PI3K/Akt/NF-κB signaling.

Hsa_circ_0044235 regulates the pyroptosis of rheumatoid arthritis via MiR-135b-5p-SIRT1 axis

ABSTRACT Studies have found that cell pyroptosis is involved in the occurrence and development of rheumatoid arthritis (RA). Hsa_circ_0044235 has been found to be significantly low-expressed in RA patients. The purpose of this research was to reveal the regulatory mechanism of hsa_circ_0044235 in the pyroptosis pathway of RA. Serum expressions of hsa_circ_0044235 and SIRT were detected by RT-qPCR, and the relationship of the two genes was analyzed by Pearson. Next, a collagen-induced arthritis (CIA) mouse model was constructed to examine the effect of hsa_circ_0044235 on knee joint injury. The number of apoptotic cells and the level of inflammatory cytokines in synovial tissue were detected by TUNEL and ELISA. Fibroblast-like synoviocytes (FLSs) were extracted as in vitro study subject. Functional assays including flow cytometry and immunofluorescence staining, molecular experiments including RT-qPCR, Western blot and dual luciferase assay, and bioinformatics analysis were performed to analyze the mechanism of hsa_circ_0044235 in pyroptosis in FLSs. Hsa_circ_0044235 and SIRT1 expressions were suppressed in RA patients and the two were positively correlated. Overexpressed hsa_circ_0044235 attenuated joint inflammation, cell apoptosis, and joint damage, reduced foot pad thickness, clinical case scores, inhibited the NLRP3-mediated pyroptosis pathway but promoted SIRT1 expression in CIA mice. Overexpressed hsa_circ_0044235 inhibited caspase-1 content and the NLRP3-mediated pyroptosis pathway. Moreover, hsa_circ_0044235 promoted SIRT1 expression by sponging miR-135b-5p in FLSs. Additionally, the effect of overexpressed hsa_circ_0044235 on FLSs was reversed by miR-135b-5p mimic and siSIRT1, while the effect of siSIRT1 was reversed by miR-135b-5p inhibitor. Hsa_circ_0044235 regulated NLRP3-mediated pyroptosis through miR-135b-5p-SIRT1 axis to regulate the development of RA.

Melatonin-induced lncRNA LINC01512 prevents Treg/Th17 imbalance by promoting SIRT1 expression in necrotizing enterocolitis

Despite the fact that melatonin regulates the expression of long noncoding RNAs (lncRNAs) under different physiological and pathological conditions, it has not been confirmed whether melatonin-induced lncRNAs regulate the differentiation of Treg and Th17 cells. Herein, we show that the expression of LINC01512 is significantly down-regulated and correlates with imbalanced Treg/Th17 ratios in necrotising enterocolitis (NEC) tissues. Through gain- and loss-of-function approaches, we found that LINC01512 promotes the differentiation of Treg cells but interferes with that of Th17 cells. Mechanistically, LINC01512 promotes SIRT1 in Treg and Th17 cells, and subsequently enhances the differentiation of Treg cells and inhibits that of Th17 cells. Furthermore, we demonstrate that melatonin up-regulates the transcription of LINC01512 via the AMPK signalling pathway and that the blockade of AMPK represses LINC01512 expression in Treg and Th17 cells. Overall, our results confirm that SIRT1-regulated differentiation of Treg/Th17 cells is actually modulated by melatonin-induced LINC0512. Moreover, manipulation of the AMPK/LINC01512/SIRT1 axis via melatonin may be a novel therapeutic approach to reduce inflammation.

Protective Effect of Dihydrokaempferol on Acetaminophen-Induced Liver Injury by Activating the SIRT1 Pathway.

Acetaminophen (APAP) overdose is the leading cause of acute liver failure (ALF) in the Western world, with limited treatment opportunities. 3,5,7,4[Formula: see text]-Tetrahydroxyflavanone (Dihydrokaempferol, DHK, Aromadendrin) is a flavonoid isolated from Chinese herbs and displays high anti-oxidant and anti-inflammatory capacities. In this study, we investigated the protective effect by DHK against APAP-induced liver injury in vitro and in vivo and the potential mechanism of action. Cell viability assays were used to determine the effects of DHK against APAP-induced liver injury. The levels of reactive oxygen species (ROS), serum alanine/aspartate aminotransferases (ALT/AST), liver myeloperoxidase (MPO), and malondialdehyde (MDA) were measured and analyzed to evaluate the effects of DHK on APAP-induced liver injury. Western blotting, immunofluorescence staining, RT-PCR, and Transmission Electron Microscope were carried out to detect the signaling pathways affected by DHK. Here, we found that DHK owned a protective effect on APAP-induced liver injury with a dose-dependent manner. Meanwhile, Western blotting showed that DHK promoted SIRT1 expression and autophagy, activated the NRF2 pathway, and inhibited the translocation of nuclear p65 (NF-[Formula: see text]B) in the presence of APAP. Furthermore, SIRT1 inhibitor EX-527 aggravated APAP-induced hepatotoxicity when treating with DHK. Molecular docking results suggested potential interaction between DHK and SIRT1. Taken together, our study demonstrates that DHK protects against APAP-induced liver injury by activating the SIRT1 pathway, thereby promoting autophagy, reducing oxidative stress injury, and inhibiting inflammatory responses.

SIRT1 Is the Target Gene for 2,3,5,4'-Tetrahydroxystilbene-2-O-β-D-Glucoside Alleviating the HUVEC Senescence.

This study aimed to explore the effects of 2,3,5,4’-tetrahydroxy-stilbene-2-O-β-d-glucoside (TSG) on the senescence of human umbilical vein cells (HUVEC) induced by hydrogen peroxide (H2O2) and to identify the potential targets mediating its protective action. HUVEC cells pre-treated with TSG for 24 h were exposed to H2O2 treatment. TSG significantly decreased H2O2-induced cellular senescence, as indicated by reduced senescence-associated β-galactosidase (SA-β-gal) positive staining, the proportion of cells in the G1 phase, cell apoptosis, p21, and plasminogen activator inhibitor-1 (PAI-1) expression. Moreover, TSG promoted Sirtuin 1 (SIRT1) expression. When SIRT1 was inhibited by EX527 or SIRT1 siRNA, the effect of TSG is diminished according to the increased proportion of cells in the G1 phase, cell apoptosis, p21, and PAI-1 expression. Overall, our study established TSG as an anti-senescence compound that exerts its protective action by regulating SIRT1 expression.

Trimetazidine Inhibits Renal Tubular Epithelial Cells to Mesenchymal Transition in Diabetic Rats via Upregulation of Sirt1.

Trimetazidine (TMZ), as a metabolic regulator, is effective in treatment of coronary atherosclerotic heart disease with rare side effects in the clinic for long years. Interestingly, studies have shown that TMZ protects against several acute kidney injuries (AKI). However, the effect of TMZ on chronic kidney diseases (CKD) remains unknown. This study aimed to investigate the role of TMZ in diabetic nephropathy (DN) and its potential mechanisms. A rat model of DN was established in male Sprague-Dawley rats by streptozotocin (STZ) intraperitoneal injection. Experimental rats were separated into three groups: control, DN and DN + TMZ treatment. Metabolic parameters, pathological features and renal function markers were evaluated after 20 weeks of diabetes induction. In vitro experiments, the effect of TMZ on high fat and high glucose (HFG) induced or TGFβ1-induced epithelial-to-mesenchymal transition (EMT) was examined in HK-2 cells. Our results showed that TMZ could maintain renal function without affecting hemodynamic and plasma metabolic levels in diabetic rats. The effect was associated with a reversion of pathological progression of DN, especially for tubulointerstitial fibrosis. EMT is an important contributor to renal fibrosis. In this study, we investigated the role of TMZ in the process of EMT in DN. Mechanistically; TMZ attenuated HFG-induced EMT by relieving oxidative stress via deacetylation forkhead box O1 (FoxO1) in a Sirt1-dependent pathway. And it suppressed TGFβ1-induced EMT by deacetylating Smd4 in a Sirt1-dependent manner. Moreover, our study found that TMZ upregulated Sirt1 expression by increasing the expression of nicotinamide phosphoribosyl transferase (Nampt), which is a rate limiting enzyme for nicotinamide adenine dinucleotide (NAD+) generation by salvage pathway. And the increased NAD+ promoted Sirt1 expression. In conclusion, TMZ can prevent renal dysfunction and pathogenesis of tubulointerstitial fibrosis in DN, partly by inhibition of EMT via FoxO1/ROS pathway and TGFβ/Smad pathway in a Nampt/NAD+/Sirt1 dependent manner.

Astragalin Exerted Antidepressant-like Action through SIRT1 Signaling Modulated NLRP3 Inflammasome Deactivation.

Inflammation plays a key role in the pathogenesis of depression and antidepressant therapies. Astragalin (AST) is a bioactive flavonoid that possesses an anti-inflammatory property. However, the antidepressant action of astragalin has not been addressed. In this study, we explored the antidepressant effects of astragalin and its underlying mechanism. Our results showed that AST significantly improved the behavioral defects in chronic unpredictable mild stress (CUMS) model, promoted SIRT1 expression, and decreased the protein levels of NF-κB p65, NLRP3, cleaved capase-1, cleaved IL-1β and cleaved gasdermin D in the hippocampus. Immunohistochemistry revealed AST mitigated CUMS-induced microglia overactivation. In vitro, AST profoundly increased the cell viability in lipopolysaccharides (LPS) and adenosine triphosphate (ATP) treated BV2 cells, with upregulated SIRT1 expression and downregulated protein levels of nuclear NF-κB p65, NLRP3, cleaved capase-1, and cleaved gasdermin D. Declined cleavage of gasdermin D was observed after AST administration in immunocytochemistry. Nevertheless, the in vivo and in vitro effects of AST were compromised by SIRT1 inhibitor EX-527. These results indicated that AST possessed an antidepressant property, which was dependent on SIRT1 signaling modulated NLRP3 inflammasome deactivation.

Resveratrol-mediated SIRT1 activation attenuates ovalbumin-induced allergic rhinitis in mice

Resveratrol (RSV) is one kind of polyphenol that possesses anti-inflammatory effect. The effect of RSV in allergic rhinitis (AR) remains unclear. In this study, we investigated the protective effect of RSV against AR and explored the related signaling pathways. AR mouse model was successfully established by intraperitoneal injection with Ovalbumin (OVA). RSV administration was performed in a diet with different doses (5, 30, 50 mg/kg). Allergic symptoms were indicated by sneezing and nasal rubbing. Cytokines in serum and nasal lavage fluid (NLF) were determined by ELISA. mRNA and protein levels were detected by RT-PCR and Western blot. Our results show that RSV treatment attenuated sneezing and nasal rubbing in AR mice. It decreased histamine release, OVA-specific IgE, IgG1, IL-4 and LTC4, inflammatory cell numbers (leucocytes, eosinophils, lymphocytes, and neutrophils), and inflammatory cytokines secretion (TNF-α, IL-6, IL-10, IL-5, IL-13, and IL-17). Mechanically, RSV treatment suppressed HMGB1 and TLR4 expression and promoted SIRT1 expression in the nasal mucosa. In conclusion, RSV is able to attenuate OVA-induced AR in mice.

Apigenin Prevents Acetaminophen-Induced Liver Injury by Activating the SIRT1 Pathway.

Acetaminophen (APAP) overdose is the main cause of acute liver failure. Apigenin (API) is a natural dietary flavonol with high antioxidant capacity. Herein, we investigated protection by API against APAP-induced liver injury in mice, and explored the potential mechanism. Cell viability assays and mice were used to evaluate the effects of API against APAP-induced liver injury. Western blotting, immunofluorescence staining, RT-PCR, and Transmission Electron Microscope were carried out to determine the signalling pathways affected by API. Analysis of mouse serum levels of alanine/aspartate aminotransferase (ALT/AST), malondialdehyde (MDA), liver myeloperoxidase (MPO) activity, glutathione (GSH), and reactive oxygen species (ROS) revealed that API (80 mg/kg) owned protective effect on APAP-induced liver injury. Meanwhile, API ameliorated the decreased cell viability in L-02 cells incubated by APAP with a dose dependent. Furthermore, API promoted SIRT1 expression and deacetylated p53. Western blotting showed that API promoted APAP-induced autophagy, activated the NRF2 pathway, and inhibited the transcriptional activation of nuclear p65 in the presence of APAP. Furthermore, SIRT1 inhibitor EX-527 reduced protection by API against APAP-induced hepatotoxicity. Molecular docking results indicate potential interaction between API and SIRT1. API prevents APAP-induced liver injury by regulating the SIRT1-p53 axis, thereby promoting APAP-induced autophagy and ameliorating APAP-induced inflammatory responses and oxidative stress injury.