SIRT1 mRNA Research Articles

Effects of follicle-stimulating hormone, insulin-like growth factor 1, fibroblast growth factor 2, and fibroblast growth factor 9 on sirtuins expression and histone deacetylase activity in bovine granulosa cells

Granulosa cells (GC) are critical regulators of fertility. During the process of ovarian folliculogenesis, these cells undergo profound changes while producing steroid hormones that are important to control follicular growth, oocyte maturation, and ovulation. Sirtuins are enzymes that regulate several biological processes and have been associated with control of GC function. However, how sirtuins are regulated in GC during ovarian folliculogenesis remains to be unveiled. The present study was designed to investigate effects of hormones that control GC proliferation, differentiation, and steroidogenesis on expression of the seven members of the mammalian sirtuins family (SIRT1-7) and on histone deacetylase activity of nuclear sirtuins (SIRT1, 6, and 7) in GC. Bovine granulosa cells were isolated from small antral follicles (1–5 mm) and were treated with or without follicle-stimulating hormone (FSH), insulin-like growth factor 1 (IGF-1), and fibroblast growth factors 2 (FGF2) and 9 (FGF9). Following treatments, cell proliferation was determined via a cell analyzer, estradiol synthesis and histone deacetylase activity were determined via ELISA, and sirtuins mRNA expression was determined via qPCR. Treatments with FSH and IGF-1 stimulated cell proliferation while addition of FGF2 or FGF9 suppressed estradiol production stimulated by FSH plus IGF-1. In terms of treatments that regulated sirtuins expression in GC, fibroblast growth factors were the most impactful: FGF2 alone increased SIRT1 mRNA expression in comparison to several treatments and increased mRNA abundance of SIRT2 and SIRT7 when added to the combination of FSH and IGF-1; the addition of FGF9 to the combination of FSH and IGF-1 increased mRNA expression of SIRT2, SIRT3, SIRT4, SIRT6, and SIRT7 and increased mRNA expression of SIRT5 in comparison to the negative control group that received no treatment. Also, FGF2 alone increased histone deacetylase activity of sirtuins in comparison to all treatments that contained FSH and/or IGF-1. Furthermore, several correlations were observed between treatments and sirtuins expression and activity, between estradiol or GC numbers and sirtuins expression, and between expression of sirtuins. As FGF2 and FGF9 are considered anti-differentiation factors of GC that stimulate GC proliferation while suppressing estradiol production in combination with FSH and IGF-1, data of this study suggest that sirtuins are associated with control of differentiation of bovine GC.

METTL3-mediated m6A modification of SIRT1 mRNA inhibits progression of endometriosis by cellular senescence enhancing

BackgroundEndometriosis (EMs), the ectopic planting of functional endometrium outside of the uterus, is a leading cause of infertility and pelvic pain. As a fundamental mRNA modification, N6-methyladenosine (m6A) participates in various pathological processes. However, the role of m6A RNA modification in endometriosis remains unclear. The present study explores METTL3-mediated m6A modification and the mechanisms involved in endometriosis.MethodsThe dominant m6A regulators in EMs were analysed using RT‒PCR. Candidate targets and possible mechanisms of METTL3 were assessed by m6A-mRNA epitranscriptomic microarray and RNA sequencing. A primary ESCs model was employed to verify the effect of METTL3 on m6A modification of SIRT1 mRNA, and the mechanism was elucidated by RT‒PCR, Western blotting, MeRIP, and RIP assays. CCK-8 viability assays, Transwell invasion assays, EdU proliferation assays, wound healing migration assays, and senescence-associated β-galactosidase staining were performed to illuminate the potential biological mechanism of METTL3 and SIRT1 in ESCs in vitro. An in vivo PgrCre/ + METTL3 −/− female homozygous mouse model and a nude mouse xenograft model were employed to further investigate the physiologic consequences of METTL3-mediated m6A alteration on EMs.ResultsOur data show that decreased METTL3 expression significantly downregulates m6A RNA methylation levels in ESCs. Silencing m6A modifications mediated by METTL3 accelerates ESCs viability, proliferation, migration, and invasion in vitro. The m6A reader protein YTHDF2 binds to m6A modifications to induce the degradation of SIRT1 mRNA. SIRT1/FOXO3a signalling pathway activation is subsequently inhibited, promoting the cellular senescence of ESCs and inhibiting the ectopic implantation of ESCs in vitro and in vivo.ConclusionsOur findings demonstrate that METTL3-mediated m6A methylation epigenetically regulates the ectopic implantation of ESCs, resulting in the progression of endometriosis. Our study establishes METTL3-YTHDF2-SIRT1/FOXO3a as a critical axis and potential mechanism in endometriosis.

Peroxinredoxin 6 reduction accelerates cigarette smoke extract‑induced senescence by regulating autophagy in BEAS‑2B cells.

Cigarette smoke (CS)-induced accelerated senescence and insufficient autophagy has been implicated in the pathogenesis of chronic obstructive pulmonary disease (COPD). Peroxiredoxin (PRDX) 6 is a protein with prevalent antioxidant capacity. Previous studies indicate that PRDX6 could activate autophagy and alleviate senescence in other diseases. The present study investigated whether PRDX6-regulated autophagy was involved in the regulation of CS extract (CSE)-induced BEAS-2B cell senescence via the knockdown of PRDX6 expression. Furthermore, the present study evaluated the mRNA levels of PRDX6, autophagy and senescence-associated genes in the small airway epithelium from patients with COPD by analyzing the GSE20257 dataset from the Gene Expression Omnibus database. The results demonstrated that CSE reduced PRDX6 expression levels and transiently induced the activation of autophagy, followed by the accelerated senescence of BEAS-2B cells. Knockdown of PRDX6 induced autophagy degradation and accelerated senescence in CSE-treated BEAS-2B cells. Furthermore, autophagy inhibition by 3-Methyladenine increased P16 and P21 expression levels, while autophagy activation by rapamycin reduced P16 and P21 expression levels in CSE-treated BEAS-2B cells. The GSE20257 dataset revealed that patients with COPD had lower PRDX6, sirtuin (SIRT) 1 and SIRT6 mRNA levels, and higher P62 and P16 mRNA levels compared with non-smokers. P62 mRNA was significantly correlated with P16, P21 and SIRT1, which indicated that insufficient autophagic clearance of damaged proteins could be involved in accelerated cell senescence in COPD. In conclusion, the present study demonstrated a novel protective role for PRDX6 in COPD. Furthermore, a reduction in PRDX6 could accelerate senescence by inducing autophagy impairment in CSE-treated BEAS-2B cells.

Fufang Zhenzhu Tiaozhi (FTZ) capsule ameliorates diabetes-accelerated atherosclerosis via suppressing YTHDF2-mediated m6A modification of SIRT3 mRNA

Ethnopharmacological relevanceFufang Zhenzhu TiaoZhi (FTZ), a Chinese medicinal decoction, has continuously been used to treat metabolic syndrome. Atherosclerosis is the main pathological basis of cardiovascular disease. The N6 methyladenosine (m6A) modification is a highly dynamic and reversible process involving a variety of important biological processes. Aim of the studyHere, we investigated the therapeutic effects and mechanism of FTZ in diabetes-accelerated atherosclerosis. Materials and methodsDoppler ultrasonography was used to examine the carotid intima-media thickness and plaque area in diabetic atherosclerosis patients. HFD mice were injected with streptozotocin to induce diabetes. HE and Oil red O staining were used to assess the effect of FTZ on lipid deposition. HUVECs were induced with HG/ox-LDL as a model of diabetic atherosclerosis. Furthermore, application of m6A methylation level kit, qRT-PCR, Western blot, tunel staining, reactive oxygen species staining and mPTP staining were performed to analyze the detailed mechanism. ResultsClinical trials of FTZ have shown obvious effect of lowering blood glucose and blood lipids. These effects were reversed after FTZ intervention. Compared with the control, lipid deposition decreased significantly after FTZ administration. FTZ reduced endothelial cell apoptosis. At the same time, we found that FTZ reversed the increase of methylation reader YTHDF2 caused by ox-LDL treatment. Subsequently, we discovered that YTHDF2 degraded SIRT3 mRNA, leading to endothelial cell apoptosis and oxidative stress. ConclusionFTZ attenuated diabetes-accelerated atherosclerosis by decreasing blood glucose and serum lipids levels, and increased endothelial cell antioxidant capacity, inhibited endothelial cell apoptosis via inhibiting YTHDF2-mediated m6A modification of SIRT3 mRNA, which reduced mRNA degradation.

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

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. 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. 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. 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.

A miRNome analysis at the early postmortem interval.

The postmortem interval (PMI) is the time elapsing since the death of an individual until the body is examined. Different molecules have been analyzed to better estimate the PMI with variable results. The miRNAs draw attention in the forensic field to estimate the PMI as they can better support degradation. In the present work, we analyzed the miRNome at early PMI in rats' skeletal muscle using the Affymetrix GeneChip™ miRNA 4.0 microarrays. We found 156 dysregulated miRNAs in rats' skeletal muscle at 24 h of PMI, out of which 84 were downregulated, and 72 upregulated. The miRNA most significantly downregulated was miR-139-5p (FC = -160, p = 9.97 × 10-11), while the most upregulated was rno-miR-92b-5p (FC = 241.18, p = 2.39 × 10-6). Regarding the targets of these dysregulated miRNAs, the rno-miR-125b-5p and rno-miR-138-5p were the miRNAs with more mRNA targets. The mRNA targets that we found in the present study participate in several biological processes such as interleukin secretion regulation, translation regulation, cell growth, or low oxygen response. In addition, we found a downregulation of SIRT1 mRNA and an upregulation of TGFBR2 mRNA at 24 h of PMI. These results suggest there is an active participation of miRNAs at early PMI which could be further explored to identify potential biomarkers for PMI estimation.

M6A eraser ALKBH5 mitigates the apoptosis of cardiomyocytes in ischemia reperfusion injury through m6A/SIRT1 axis.

Recent studies have shown that the potential regulatory role of N6-methyladenine (m6A) modification may affect the occurrence and development of various cardiovascular diseases. However, the regulatory mechanism of m6A modification on myocardial ischemia reperfusion injury (MIRI) is rarely reported. A mouse model of myocardial ischemia reperfusion (I/R) was established by ligation and perfusion of the left anterior descending coronary artery, and a cellular model of hypoxia/reperfusion (H/R) was conducted in cardiomyocytes (CMs). We found that the protein expression of ALKBH5 in myocardial tissues and cells were decreased, accompanied by increased m6A modification level. Overexpression of ALKBH5 significantly inhibited H/R-induced oxidative stress and apoptosis in CMs. Mechanistically, there was an enriched m6A motif in the 3'-UTR of SIRT1 genome, and ALKBH5 overexpression promoted the stability of SIRT1 mRNA. Furthermore, results using overexpression or knockdown of SIRT1 confirmed the protective effect of SIRT1 on H/R induced CMs apoptosis. Together, our study reveals a critical role of ALKBH5-medicated m6A on CM apoptosis, supplying an important regulating effect of m6A methylation in ischemic heart disease.

A novel pyroptosis-associated lncRNA LINC01133 promotes pancreatic adenocarcinoma development via miR-30b-5p/SIRT1 axis.

Pancreatic adenocarcinoma (PAAD) remains a highly aggressive gastrointestinal malignancy with a dismal prognosis. Pyroptosis has a key role in tumor development. Long noncoding RNAs (lncRNAs) are involved in tumorigenesis and pyroptosis regulation. However, the prognostic potential and function of pyroptosis-related lncRNAs (PRLs) in PAAD remain unclear. We aimed to identify PRLs with promising predictive value for PAAD prognosis and investigate the mechanism by which PRLs affect pyroptosis and PAAD development. Key genes that regulate pyroptosis were determined from previous studies, and PRLs were identified from lncRNAs shown to be co-expressed in The Cancer Genome Atlas. Cox analysis and the least absolute shrinkage and selection operator (LASSO) regression model was used to establish a prognostic PRL signature. The clinical significance and functional mechanisms of LINC01133 were explored in vitro and in vivo. A seven-lncRNA signature was established and the high-risk subgroup exhibited a shorter survival time. With lower immune infiltration abundance, poor immune function, and higher tumor mutational burden (TMB), the high-risk subgroup reflected a more immunosuppressive status with a greater scope for benefiting from immunotherapy. After LINC01133 knockdown, PAAD cells showed lower viability and higher pyroptosis-related gene expression. LINC01133 functioned as a competing endogenous RNA to sequester miR-30b-5p from sponging SIRT1 mRNA to inhibit PAAD pyroptosis. With significant prognostic value, our PRL signature are involved in the biological processes of PAAD cells and associated with the immune environment. LINC01133 suppresses pyroptosis to promote PAAD development and could serve as a potential target for PAAD treatment.

Shikonin Alleviates Gentamicin-Induced Renal Injury in Rats by Targeting Renal Endocytosis, SIRT1/Nrf2/HO-1, TLR-4/NF-κB/MAPK, and PI3K/Akt Cascades.

Gentamicin causes kidney injury due to its accumulation in proximal tubule epithelial cells via the megalin/cubilin/CLC-5 complex. Recently, shikonin has been shown to have potential anti-inflammatory, antioxidant, antimicrobial, and chloride channel-inhibiting effects. The current study investigated the alleviation of gentamicin-induced renal injury by shikonin while preserving its bactericidal effect. Nine-week-old Wistar rats were administered 6.25, 12.5, and 25 mg/kg/day shikonin orally, one hour after the i.p. injection of 100 mg/kg/day gentamicin for seven days. Shikonin significantly and dose-dependently alleviated gentamicin-induced renal injury, as revealed by restoring normal kidney function and histological architecture. Furthermore, shikonin restored renal endocytic function, as indicated by suppressing the elevated renal megalin, cubilin, and CLC-5 and enhancing the reduced NHE3 levels and mRNA expressions induced by gentamicin. These potentials could be attributed to the modulation of the renal SIRT1/Nrf2/HO-1, TLR-4/NF-κB/MAPK, and PI3K/Akt cascades, which enhanced the renal antioxidant system and suppressed renal inflammation and apoptosis, as indicated by enhancements of SIRT1, Nrf2, HO-1, GSH, SOD, TAC, Iκb-α, Bcl-2, PI3K, and Akt levels and mRNA expressions, with reduction of TLR-4, NF-κB, MAPK, IL-1β, TNF-α, MDA, iNOS, NO, cytochrome c, caspase-3, Bax levels, and Bax/Bcl-2 ratio. Therefore, shikonin is a promising therapeutic agent for alleviating gentamicin-induced renal injury.

Neuroprotection of SRT2104 in Murine Ischemia/Reperfusion Injury Through the Enhancement of Sirt1-Mediated Deacetylation.

Strategies for neuroprotection are the main targets of glaucoma research. The neuroprotective properties of SRT2104 administration have been proven in central nervous system degeneration diseases through the activation of nicotinamide adenine dinucleotide-dependent deacetylase-silence information regulator 1 (Sirt1). Here, we investigated whether SRT2104 could protect the retina from ischemia/reperfusion (I/R) injury and the underlying mechanisms. SRT2104 was intravitreally injected immediately after I/R induction. RNA and protein expression were detected by quantitative real-time PCR and Western blot. Protein expression and distribution were examined by immunofluorescence staining. Retinal structure and function were analyzed by hematoxylin and eosin staining, optical coherence tomography, and electroretinogram. Optic nerve axons were quantified using toluidine blue staining. Cellular apoptosis and senescence were evaluated by TUNEL assay and SA-β-gal staining. The protein expression of Sirt1 decreased dramatically after I/R injury and SRT2104 administration effectively enhanced the stability of Sirt1 protein without significantly influencing Sirt1 mRNA synthesis. SRT2104 administration alone exerted no influence on the structure and function of normal retinas. However, SRT2104 intervention significantly protected the inner retinal structure and neurons; partially restored retinal function after I/R injury. I/R-induced cellular apoptosis and senescence were effectively alleviated by SRT2104 administration. Additionally, SRT2104 intervention markedly reduced neuroinflammation, including reactive gliosis, retinal vascular inflammation, and the overexpression of pro-inflammatory cytokines after I/R injury. Mechanistically, I/R-induced acetylation of p53, NF-κB p65, and STAT3 was significantly reversed by SRT2104 intervention. We demonstrated that SRT2104 exerted potent protective effects against I/R injury by enhancing Sirt1-mediated deacetylation and suppressing apoptosis, senescence, and neuroinflammation-related pathways.

METTL3 Reduces Oxidative Stress-induced Apoptosis in Presbycusis by Regulating the N6-methyladenosine Level of SIRT1 mRNA

N6-methyl adenosine (m6A) modification is known to play a crucial role in various aging-related diseases. However, its involvement in presbycusis, a type of age-related hearing loss, is not yet clear. We examined the changes in oxidative stress levels in both plasma of presbycusis patients and mice. To determine the expression of m6A and its functional enzymes, we used liquid chromatography tandem-mass spectrometry (LC-MS/MS), enzyme-linked immunosorbent assay (ELISA), and RT-PCR to analyze the total RNA of presbycusis patients blood cells (n = 8). Additionally, we detected the expression of m6A functional enzymes in the cochlea of presbycusis mice using immunohistochemistry. We assessed the effects of m6A methyltransferase METTL3 on SIRT1 protein expression, reactive oxygen species (ROS) levels, and apoptosis in an oxidative stress model of organ of Corti 1 (OC1) cells. To observe the effect on SIRT1 protein expression, we interfered with the m6A recognition protein IGF2BP3 using siRNA. In both presbycusis patients and mice, there was an increased level of oxidative stress in plasma.There was a decrease in the expression of m6A, METTL3, and IGF2BP3 in presbycusis patients blood cells. The expression of METTL3 and IGF2BP3 was also reduced in the cochlea of presbycusis mice. In OC1 cells, METTL3 positively regulated SIRT1 protein levels, while reversely regulated the level of ROS and apoptosis. IGF2BP3 was found to be involved in the regulation of SIRT1 protein expression. In addition, METTL3 may play a protective role in oxidative stress-induced injury of OC1 cells, while both METTL3 and IGF2BP3 cooperatively regulate the level of m6A and the fate of SIRT1 mRNA in OC1 cells.

Intravitreal Administration of AAV2-SIRT1 Reverses Diabetic Retinopathy in a Mouse Model of Type 2 Diabetes.

The expression of silent information regulator (SIRT) 1 is reduced in diabetic retinopathy (DR). Previous studies showed that alterations in SIRT1 messenger RNA (mRNA) and protein expression are implicated in progressive inflammation and formation of retinal acellular capillaries. Treatment with the SIRT1 agonist, SRT1720, improved visual response by restoration of a- and b-wave responses on electroretinogram scotopic measurements in diabetic (db/db) mice. In this study, we investigated the effects of intravitreal SIRT1 delivery on diabetic retinal pathology. Nine-month-old db/db mice received one intravitreal injection of either AAV2-SIRT1 or AAV2-GFP control virus, and after 3 months, electroretinography and optomotor responses were measured. Their eyes were then removed and analyzed by immunohistochemistry and flow cytometry. SIRT1 mRNA and protein levels were increased following AAV2-SIRT1 administration compared to control virus AAV2-GFP injected mice. IBA1+ and caspase 3 expression were decreased in retinas of db/db mice injected with AAV2-SIRT1, and reductions in scotopic a- and b-waves and high spatial frequency in optokinetic response were prevented. Retinal hypoxia inducible factor 1α (HIF-1α) protein levels were reduced in the AAV2-SIRT1-injected mice compared to control-injected mice. Using flow cytometry to assess changes in intracellular HIF-1α levels, endothelial cells (CD31+) from AAV-2 SIRT1 injected mice demonstrated reduced HIF-1α expression compared to db/db mice injected with the control virus. Intravitreal AAV2-SIRT1 delivery increased retina SIRT1 and transduced neural and endothelial cells, thus reversing functional damage and improving overall visual function. AAV2-SIRT1 gene therapy represents a beneficial approach for the treatment of chronic retinal conditions such as DR.

Identification of HDAC4 as a potential therapeutic target and prognostic biomarker for ZFTA-fused ependymomas.

Members of the HDAC family are predictive biomarkers and regulate the tumorigenesis in several cancers. However, the role of these genes in the biology of intracranial ependymomas (EPNs) remains unexplored. Here, an analysis of eighteen HDACs genes in an EPN transcriptomic dataset, revealed significantly higher levels of HDAC4 in supratentorial ZFTA fusion (ST-ZFTA) compared with ST-YAP1 fusion and posterior fossa EPNs, while HDAC7 and SIRT2 were downregulated in ST-ZFTA. HDAC4 was also overexpressed in ST-ZFTA as measured by single-cell RNA-Seq, quantitative real time-polymerase chain reaction, and immunohistochemistry. Survival analyses showed a significantly worse outcome for EPNs with higher HDAC4 and SIRT1 mRNA levels. Ontology enrichment analysis showed an HDAC4-high signature consistent with viral processes while collagen-containing extracellular matrix and cell-cell junction were enriched in those with an HDAC4-low signature. Immune gene analysis demonstrated a correlation between HDAC4 expression and low levels of NK resting cells. Several small molecules compounds targeting HDAC4 and ABCG2, were predicted by in silico analysis to be effective against HDAC4-high ZFTA. Our results provide novel insights into the biology of the HDAC family in intracranial ependymomas and reveal HDAC4 as a prognostic marker and potential therapeutic target in ST-ZFTA.

Age-related effects of fenofibrate on the hepatic expression of sirtuin 1, sirtuin 3, and lipid metabolism-related genes.

Sirtuin 1 (Sirt1) and sirtuin 3 (Sirt3) participate in the regulation of lipid metabolism. Our aim was to investigate the effects of the hypolipemic drug fenofibrate (FN) on hepatic Sirt1 and Sirt3 expression, in relation to the expression of lipid metabolism-related genes and in the context of aging. Young and old male Wistar rats were fed standard chow or supplemented with 0.1% or 0.5% FN for 30 days (n=7-10 in each group). In young rats, 0.1% FN did not affect Sirt1 expression, however, 0.5% FN decreased Sirt1 and both doses reduced Sirt3 protein levels. In old rats, 0.5% FN decreased hepatic Sirt1 mRNA and both doses reduced Sirt1 protein levels, but not Sirt3 expression. Although hepatic Pparα protein levels did not change, FN treatment of young rats induced Cpt1b expression, whereas Lcad, Acox1, Pmp70, and Hmgcs2 expression increased only after 0.1% FN, and Fas2 expression decreased after 0.5% FN. In the liver of old rats, both doses increased Cpt1b and Lcad expression. Only 0.1% FN increased Pmp70 and Hmgcs2 expression, and only 0.5% FN increased Acox1 and Fas2 mRNA levels. Treatment with fenofibrate at low or high doses may downregulate the expression of Sirt1 and Sirt3 proteins in the rat liver. The dosage of FN affects molecular changes, and aging alters the response to 0.5% FN.

Moringa oleifera Lam Leaf Extract Stimulates NRF2 and Attenuates ARV-Induced Toxicity in Human Liver Cells (HepG2)

The World Health Organization (WHO) reported that there are 37 million individuals living with the human immunodeficiency virus (HIV) worldwide, with the majority in South Africa. This chronic disease is managed by the effective use of antiretroviral (ARV) drugs. However, with prolonged use, ARV drug-induced toxicity remains a clinically complex problem. This study investigated the toxicity of ARV drugs on mitochondria and the NRF2 antioxidant pathway and its possible amelioration using Moringa oleifera Lam (MO) leaf extracts. This medicinal plant has a range of functional bioactive compounds. Liver (HepG2) cells were treated with individual ARV drugs: Tenofovir disoproxil fumarate (TDF), Emtricitabine (FTC), and Lamivudine (3TC) for 96 h, followed by MO leaf extracts for 24 h. Intracellular ROS, cytotoxicity, lipid peroxidation, total and reduced glutathione (GSH), ATP, and mitochondrial polarisation were determined. Finally, protein (pNRF2, NRF2, SOD2, CAT, and Sirt3) and mRNA (NRF2, CAT, NQO1 SOD2, Sirt3, and PGC1α) expression were measured using Western blot and qPCR, respectively. TDF, FTC, and 3TC significantly increased intracellular ROS and extracellular levels of both MDA and LDH. ARVs also reduced the GSH and ATP levels and altered the mitochondrial polarization. Further, ARVs reduced the expression of NRF2 SOD2, Sirt3, CAT, NQO1, UCP2 and PGC1α mRNA and consequently pNRF2, NRF2, SOD2, Sirt3 and CAT protein. In contrast, there was a significant reduction in the extracellular MDA and LDH levels post-MO treatment. MO significantly reduced intracellular ROS while significantly increasing GSH, ATP, and mitochondrial membrane polarization. The addition of MO to ARV-treated cells significantly upregulated the expression of NRF2, SOD2, Sirt3, CAT, UCP2, PGC1α, and NQO1 mRNA and pNRF2, NRF2, SOD2, Sirt3 proteins. Thus, MO ameliorates ARV-induced hepatotoxicity by scavenging oxidants by inducing the NRF2 antioxidant pathway. MO shows great therapeutic potential and may be considered a potential supplement to ameliorate ARV drug toxicity.

LncRNA GMDS-AS1 restrains lung adenocarcinoma progression via recruiting TAF15 protein to stabilize SIRT1 mRNA.

Aim: To explore the roles of GMDS-AS1 in the epithelial-mesenchymal transition (EMT) of lung adenocarcinoma (LUAD). Materials & methods: Cell functions were detected by flow cytometry, cell counting kit-8, wound healing assays and transwell assays. RNA immunoprecipitation and pull-down assays were applied for determining the interaction among GMDA-AS1, TAF15 and SIRT1. A subcutaneous xenograft model was established. Results: GMDS-AS1 downregulation was associated with poor survival of LUAD patients. GMDS-AS1 repressed malignant phenotypes, tumor growth and EMT in vitro and in vivo. Mechanically, GMDS-AS1 recruited TAF15 protein to stabilize SIRT1 mRNA and thereby deacetylated p65 and reduced the recruitment of p65 to MMP-9 promoter, thus inhibiting MMP-9 expression. Conclusion: GMDS-AS1 represses EMT by recruiting TAF15 protein to stabilize SIRT1 mRNA and deacetylate p65, thus restraining LUAD progression.

YT521-B homology domain containing 1 ameliorates mitochondrial damage and ferroptosis in sleep deprivation by activating the sirtuin 1/nuclear factor erythroid-derived 2-like 2/heme oxygenase 1 pathway

In sleep deprivation (SD) models, ferroptosis is increased. SIRT1 alleviates cognitive impairment in SD, and SIRT1/NRF2/HO1 pathway depresses ferroptosis in different diseases. Moreover, YTHDC1 can regulate SIRT1 mRNA stability. Therefore, our study explored effects of the YTHDC1/SIRT1/NRF2/HO1 axis on neuronal damage and ferroptosis in SD. The SD mouse model was established through a modified multi-platform water environment method and a cell model of ferroptosis was constructed with Erastin, followed by gain- and loss-of-function assays. In mice, the cognitive impairment and CLOCK and BMAL1 levels in hippocampal tissues were assessed. In cells, viability was measured. In mice and cells, mitochondrial ultrastructure, the content of reactive oxygen species (ROS), malondialdehyde (MDA), glutathione (GSH), and iron, and the expression of GPX4 and ACSL4 were detected. The potential relationships among YTHDC1, SIRT1, and NRF2 were analyzed. SD mice had downregulated YTHDC1, SIRT1, NRF2, and HO1 protein expression in hippocampal tissues and increased ferroptosis. Mechanically, SIRT1 activated the NRF2/HO1 pathway through deacetylation, and YTHDC1 increased SIRT1 mRNA stability. YTHDC1 overexpression diminished mitochondrial damage, the content of ROS, iron, and MDA, and the expression of ACSL4 while enhancing GSH contents and GPX4 expression in hippocampal tissues of SD mice and Erastin-induced HT22 cells. Additionally, YTHDC1 overexpression elevated viability in Erastin-induced HT22 cells. SIRT1 or NRF2 overexpression ameliorated Erastin-induced mitochondrial damage and ferroptosis in HT22 cells. Silencing SIRT1 abolished the impact of YTHDC1 overexpression on SD mice and Erastin-induced HT22 cells. Collectively, YTHDC1 ameliorates mitochondrial damage and ferroptosis after SD by activating the SIRT1/NRF2/HO1 pathway.

SIRT1 Inhibits High Glucose-Induced TXNIP/NLRP3 Inflammasome Activation and Cataract Formation.

To determine whether SIRT1 regulates high glucose (HG)-induced inflammation and cataract formation through modulating TXNIP/NLRP3 inflammasome activation in human lens epithelial cells (HLECs) and rat lenses. HG stress from 25 to 150 mM was imposed on HLECs, with treatments using small interfering RNAs (siRNAs) targeting NLRP3, TXNIP, and SIRT1, as well as a lentiviral vector (LV) for SIRT1. Rat lenses were cultivated with HG media, with or without the addition of NLRP3 inhibitor MCC950 or SIRT1 agonist SRT1720. High mannitol groups were applied as the osmotic controls. Real-time PCR, Western blots, and immunofluorescent staining evaluated the mRNA and protein levels of SIRT1, TXNIP, NLRP3, ASC, and IL-1β. Reactive oxygen species (ROS) generation, cell viability, and death were also assessed. HG stress induced a decline in SIRT1 expression and caused TXNIP/NLRP3 inflammasome activation in a concentration-dependent manner in HLECs, which was not observed in the high mannitol-treated groups. Knocking down NLRP3 or TXNIP inhibited NLRP3 inflammasome-induced IL-1β p17 secretion under HG stress. Transfections of si-SIRT1 and LV-SIRT1 exerted inverse effects on NLRP3 inflammasome activation, suggesting that SIRT1 acts as an upstream regulator of TXNIP/NLRP3 activity. HG stress induced lens opacity and cataract formation in cultivated rat lenses, which was prevented by MCC950 or SRT1720 treatment, with concomitant reductions in ROS production and TXNIP/NLRP3/IL-1β expression levels. The TXNIP/NLRP3 inflammasome pathway promotes HG-induced inflammation and HLEC pyroptosis, which is negatively regulated by SIRT1. This suggests viable strategies for treating diabetic cataract.

METTL14 alleviates the development of osteoporosis in ovariectomized mice by upregulating m6A level of SIRT1 mRNA.

The purpose of this study was to investigate whether METTL14 participated in ovariectomized (OVX)-induced osteoporosis (OP) in mice by regulating the m6A level of SIRT1 mRNA. OVX was performed on mice to induce OP, and mouse bone marrow stromal cells (BMSCs) and bone marrow mononuclear macrophages (BMMs) were isolated to induce osteoblast differentiation and osteoclast differentiation, respectively. The morphology of bone trabeculae was evaluated under a micro-CT scanner. The changes in pathology of bone tissues were observed through staining using hematoxylin-eosin. The number of osteoclasts was measured by tartrate-resistant acid phosphatase staining, and the content of serum calcium, PINP, and CTX-I was tested by enzyme-linked immunosorbent assay, accompanied by the measurement of the expression of SIRT1, METTL14, osteogenic marker genes, and osteoclast marker genes. The m6A modification level of SIRT1 and the binding between METTL14 and SIRT1 were verified. In OVX mice, SIRT1 and METTL14 were downregulated. Overexpression of SIRT1 or METTL14 increased the expression of osteogenic marker genes but decreased the expression of osteoclast marker genes. Additionally, METTL14 overexpression increased m6A level of SIRT1 mRNA. Furthermore, overexpression of METTL14 promoted osteoblast differentiation and suppressed osteoclast differentiation, which were reversed by knockdown of SIRT1. METTL14 promoted osteoblast differentiation and repressed osteoclast differentiation by m6A-dependent upregulation of SIRT1 mRNA, thereby alleviating OP development.

Intermittent fasting promotes adipocyte mitochondrial fusion through Sirt3-mediated deacetylation of Mdh2.

Fat deposition and lipid metabolism are closely related to the morphology, structure and function of mitochondria. The morphology of mitochondria between fusion and fission processes is mainly regulated by protein posttranslational modification. Intermittent fasting (IF) promotes high expression of Sirtuin 3 (Sirt3) and induces mitochondrial fusion in high-fat diet (HFD)-fed mice. However, the mechanism by which Sirt3 participates in mitochondrial protein acetylation during IF to regulate mitochondrial fusion and fission dynamics remains unclear. This article demonstrates that IF promotes mitochondrial fusion and improves mitochondrial function in HFD mouse inguinal white adipose tissue. Proteomic sequencing revealed that IF increased protein deacetylation levels in HFD mice and significantly increased Sirt3 mRNA and protein expression. After transfecting with Sirt3 overexpression or interference vectors into adipocytes, we found that Sirt3 promoted adipocyte mitochondrial fusion and improved mitochondrial function. Furthermore, Sirt3 regulates the JNK-FIS1 pathway by deacetylating malate dehydrogenase 2 (MDH2) to promote mitochondrial fusion. In summary, our study indicates that IF promotes mitochondrial fusion and improves mitochondrial function by upregulating the high expression of Sirt3 in HFD mice, promoting deacetylation of MDH2 and inhibiting the JNK-FIS1 pathway. This research provides theoretical support for studies related to energy limitation and animal lipid metabolism.