SIRT1 Protein Research Articles

Antiretrovirals Promote Metabolic Syndrome through Mitochondrial Stress and Dysfunction: An In Vitro Study.

The prevalence of metabolic syndrome MetS in HIV-infected patients on chronic antiretroviral (ARV) therapy continues to rise rapidly, with an estimated 21% experiencing insulin resistance. The progression of insulin resistance is strongly related to mitochondrial stress and dysfunction. This study aimed to draw links between the singular and combinational use of Tenofovir disoproxil fumarate (TDF), Lamivudine (3TC), and Dolutegravir (DTG) on mitochondrial stress and dysfunction as an underlying mechanism for insulin resistance following a 120 h treatment period using an in vitro system of human liver cells (HepG2). The relative protein expressions of pNrf2, SOD2, CAT, PINK1, p62, SIRT3, and UCP2, were determined using Western blot. Transcript levels of PINK1 and p62 were assessed using quantitative PCR (qPCR). ATP concentrations were quantified using luminometry, and oxidative damage (malondialdehyde (MDA) concentration) was measured using spectrophotometry. The findings suggest that despite the activation of antioxidant responses (pNrf2, SOD2, CAT) and mitochondrial maintenance systems (PINK1 and p62) in selected singular and combinational treatments with ARVs, oxidative damage and reduced ATP production persisted. This was attributed to a significant suppression in mitochondrial stress responses SIRT3 and UCP2 for all treatments. Notable results were observed for combinational treatments with significant increases in pNrf2 (p = 0.0090), SOD2 (p = 0.0005), CAT (p = 0.0002), PINK1 (p = 0.0064), and p62 (p = 0.0228); followed by significant decreases in SIRT3 (p = 0.0003) and UCP2 (p = 0.0119) protein expression. Overall there were elevated levels of MDA (p = 0.0066) and decreased ATP production (p = 0.0017). In conclusion, ARVs induce mitochondrial stress and dysfunction, which may be closely associated with the progression of insulin resistance.

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.

NDRG2 inhibition of glycolysis in liver tumor cells is regulated by SIRT1.

N-Myc downstream-regulated gene 2 (NDRG2) is a tumor suppressor, highly expressed in normal tissues but downregulated in many cancers. However, it has been shown to be involved in regulating glycolytic enzymes in clear cell renal cell carcinoma and colorectal cancer, although the mechanism is still not clear, and the function of NDRG2 in liver tumor glycolysis is completely unknown. Liver tumor tissues were obtained from resected tumors and confirmed by pathological review. Immunohistochemical staining was performed to assess the protein expression of NDRG2. NDRG2-overexpressed and knockdown HepG2/SMMC-7721 cell lines were infected by lentivirus and cultured, before measurement of glucose uptake, lactate production, lactase dehydrogenase activity, and oxygen consumption rate. NDRG2 and SIRT1 proteins were analyzed by western blot. Both the mRNA and protein levels of NDRG2 as a tumor suppressor were downregulated in the liver tumors and the survival rate of patients negatively correlated with the expression of NDRG2. In the NDRG2-overexpressed and knockdown cell lines, NDRG2 showed inhibition of glycolysis in liver tumor cells. Our experimental data suggested the expression of SIRT1 negatively correlated with that of NDRG2. Our study findings enrich the understanding of the role of NDRG2 in tumor growth and of the mechanism by which NDRG2 regulates glycolysis. SIRT1, a deacetylase that plays an important role in glycolysis regulation, may be negatively regulated by NDRG2 in liver tumors.

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.

Design, synthesis, and biological screening of a series of pyrazolo [1,5-a]quina-zoline derivatives as SIRT6 activators

SIRT6 has emerged as a novel therapeutic target for a variety of diseases. In this study, a total of 102 pyrazolo [1,5-a]quinazoline derivatives were designed and synthesized. The result revealed that 2-methyl-N-(4-phenoxy-phenyl)pyrazolo [1,5-a]quinazoline-5-amine (21q) was the most active compound by structure-activity relationship study, which significantly enhanced SIRT6 defatty-acylation activity with an EC1.5 value of 1.85±0.41 μM and EC50 value of 11.15±0.33 μM. The biological activity of 21q was further verified by differential scanning fluorimetry assay (DSF) and surface plasmon resonance assay (SPR). Molecular docking showed that the pyrazolo [1,5-a]quinazoline of 21q formed a hydrogen bond with Val115 and four π- π interactions with Phe64, Phe82 and Phe86. 21q can significantly improve the thermal stability of SIRT6 protein and inhibit the PI3K/Akt signaling pathway in mouse embryonic fibroblasts (MEFs), thereby inhibiting the proliferation of MEFs. Collectively, we discovered a new potent SIRT6 activator, which can be taken as a lead compound for later studies.

Mito-battery: Micro-nanohydrogel microspheres for targeted regulation of cellular mitochondrial respiratory chain

The mitochondrial respiratory chain (MRC) plays an essential role in regulating cellular energy metabolism and oxidative stress. Repairing damaged MRC function can efficiently provide cells with energy to fight inflammation. Herein, with the inspiration by a rechargeable battery, microfluidics was used to prepare hyaluronic acid hydrogel microspheres as shells and con-covalently connected the inner core-SS-31 peptide and Wyrgrl peptide co-modified long-circulating liposomes loaded with resveratrol (REV) to the nanonetwork of microspheres to construct a "Mito-Battery" that could promote cell energy production and fight inflammation by targeted regulation of MRC functions. Modification of peptide could increase its cellular uptake and enhance the mitochondrial-targeting of "Mito-Battery." Meanwhile, REV loaded in the liposomes can activate SIRT3 protein and synergistically enhance the MRC electron transfer efficiency with SS-31. "Mito-Battery" effectively delayed the progression of the disease in a rat bone and joint model. Thus, “Mito-Battery” has great potential in the treatment of degenerative diseases related to MRC dysfunction.

Oxidative stress impairs the Nur77-Sirt1 axis resulting in a decline in organism homeostasis during aging.

Sirt1 is an NAD+ -dependent deacetylase that protects against premature aging and cell senescence. Aging accompanied by oxidative stress leads to a decrease in Sirt1 levels and activity, but the regulatory mechanism that connects these events remains unclear. Here, we reported that Nur77, which shares similar biological pathways with Sirt1, was also decreased with age in multiple organs. Our in vivo and in vitro results revealed that Nur77 and Sirt1 decreased during aging and oxidative stress-induced cell senescence. Deletion of Nr4a1 shortened the lifespan and accelerated the aging process in multiple mouse tissues. Overexpression of Nr4a1 protected the Sirt1 protein from proteasomal degradation through negative transcriptional regulation of the E3 ligase MDM2. Our results showed that Nur77 deficiency markedly aggravated aging-related nephropathy and elucidated a key role for Nur77 in the stabilization of Sirt1 homeostasis during renal aging. We proposed a model wherein a reduction of Nur77 in response to oxidative stress promotes Sirt1 protein degradation through MDM2, which triggers cell senescence. This creates additional oxidative stress and provides positive feedback for premature aging by further decreasing Nur77 expression. Our findings reveal the mechanism by which oxidative stress reduces Sirt1 expression during aging and offers an attractive therapeutic strategy for targeting aging and homeostasis in organisms.

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.

Apolipoprotein M/sphingosine 1-phosphate protects against diabetic nephropathy

Diabetic nephropathy remains a common cause of end-stage renal failure and its associated mortality around the world. Sphingosine 1-phosphate (S1P) is a multifunctional lipid mediator and binds to HDL via apolipoprotein M (ApoM). Since HDL has been reported to be epidemiologically associated with kidney disease, we attempted to investigate the involvement of the ApoM/S1P axis in the pathogenesis/progression of diabetic nephropathy. In type 2 diabetic patients, the serum ApoM levels were inversely correlated with the clinical stage of diabetic nephropathy. The decline in the eGFR over a 5-year observation period proceeded more rapidly in subjects with lower serum ApoM levels. In a mouse model of streptozotocin-induced diabetes, deletion of ApoM deteriorated the phenotypes of diabetic nephropathy: the urinary albumin and plasma creatinine levels increased, the kidneys enlarged, and renal fibrosis and thickening of the basement membrane progressed. On the other hand, overexpression of ApoM ameliorated these phenotypes. These protective effects of ApoM were partially inhibited by treatment with VPC23019, an antagonist of S1P1 and S1P3, but not by treatment with JTE013, an antagonist of S1P2. ApoM/S1P axis attenuated activation of the Smad3 pathway, while augmented eNOS phosphorylation through the S1P1 pathway. Moreover, ApoM/S1P increased the SIRT1 protein levels and enhanced mitochondrial functions by increasing the S1P content of the cell membrane, which might cause selective activation of S1P1. ApoM might be a useful biomarker for predicting the progression of diabetic nephropathy, and the ApoM/S1P-S1P1 axis might serve as a novel therapeutic target for preventing the development/progression of diabetic nephropathy.

Sex-divergent effects on the NAD+-dependent deacetylase sirtuin signaling across the olfactory–entorhinal–amygdaloid axis in Alzheimer’s and Parkinson’s diseases

BackgroundSmell impairment is one of the earliest features in Alzheimer’s (AD) and Parkinson’s diseases (PD). Due to sex differences exist in terms of smell and olfactory structures as well as in the prevalence and manifestation of both neurological syndromes, we have applied olfactory proteomics to favor the discovery of novel sex-biased physio-pathological mechanisms and potential therapeutic targets associated with olfactory dysfunction.MethodsSWATH-MS (sequential window acquisition of all theoretical fragment ion spectra mass spectrometry) and bioinformatic workflows were applied in 57 post-mortem olfactory tracts (OT) derived from controls with no known neurological history (n = 6F/11M), AD (n = 4F/13M) and PD (n = 7F/16M) subjects. Complementary molecular analyses by Western-blotting were performed in the olfactory bulb (OB), entorhinal cortex (EC) and amygdala areas.Results327 and 151 OT differentially expressed proteins (DEPs) were observed in AD women and AD men, respectively (35 DEPs in common). With respect to PD, 198 DEPs were identified in PD women, whereas 95 DEPs were detected in PD men (20 DEPs in common). This proteome dyshomeostasis induced a disruption in OT protein interaction networks and widespread sex-dependent pathway perturbations in a disease-specific manner, among them Sirtuin (SIRT) signaling. SIRT1, SIRT2, SIRT3 and SIRT5 protein levels unveiled a tangled expression profile across the olfactory–entorhinal–amygdaloid axis, evidencing disease-, sex- and brain structure-dependent changes in olfactory protein acetylation.ConclusionsAlteration in the OT proteostasis was more severe in AD than in PD. Moreover, protein expression changes were more abundant in women than men independent of the neurological syndrome. Mechanistically, the tangled SIRT profile observed across the olfactory pathway-associated brain regions in AD and PD indicates differential NAD (+)-dependent deacetylase mechanisms between women and men. All these data shed new light on differential olfactory mechanisms across AD and PD, pointing out that the evaluation of the feasibility of emerging sirtuin-based therapies against neurodegenerative diseases should be considered with caution, including further sex dimension analyses in vivo and in clinical studies.

HypERlnc attenuates angiotensin II-induced cardiomyocyte hypertrophy via promoting SIRT1 SUMOylation-mediated activation of PGC-1α/PPARα pathway in AC16 cells.

Cardiac hypertrophy is a well-established risk factor for cardiovascular mortality worldwide. According to a recent study, hypoxia-induced endoplasmic reticulum stress regulating long noncoding RNA (HypERlnc) is significantly reduced in the left ventricular myocardium of heart failure (HF) patients compared with healthy controls. However, the effect of HypERlnc on hypertrophy is unclear. In this study, the expression level of HypERlnc in serum of patients with chronic HF was analyzed. Moreover, the cardioprotective effect and mechanism of HypERlnc against cardiomyocyte hypertrophy were explored. Here, the level of HypERlnc expression was reduced in serum of patients with HF and in Angiotensin II (Ang II)-stimulated AC16 cells. HypERlnc overexpression could reduce cell size and inhibit expression of hypertrophy genes (ANP, BNP, and β-MHC) in the Ang II-induced cardiomyocyte hypertrophy. Meanwhile, HypERlnc could improve the Ang II-induced energy metabolism dysfunction and mitochondrial damage via upregulating PGC-1α/PPARα signaling pathway. Furthermore, it is found that SIRT1 SUMOylation mediated the HypERlnc-induced inhibition of cardiomyocyte hypertrophy and the improvement of energy metabolism. Taken together, this study suggests that HypERlnc suppresses cardiomyocyte hypertrophy and energy metabolism dysfunction via enhancing SUMOylation of SIRT1 protein. HypERlnc is a potential novel molecular target for preventing and treating pathological cardiac hypertrophy.

Association between The SIRT1 and SIRT3 Levels and Gene Polymorphisms with Infertility in War Zones of Kermanshah Province, Iran: A Case-Control Study.

War toxin, mustard gas, alkylating agent results in male infertility via inducing reactive oxygen species (ROS) production and DNA mutagenesis. SIRT1 and SIRT3 are multifunctional enzymes that involve in the DNA repair, oxidative stress responses. This study aim is to assess the correlation between serum levels of SIRT1, SIRT3 and both rs3758391T>C and rs185277566C>G gene polymorphisms with infertility in the war zones of Kermanshah province, Iran. In this case-control study based on the semen analysis, samples were divided into two groups infertile (n=100) and fertile (n=100). High-performance liquid chromatography (HPLC) method was used to determine the malondialdehyde level, and also a sperm chromatin dispersion (SCD) test was used to evaluate the DNA fragmentation rate. Using the colorimetric assays, superoxide dismutase (SOD) activity was measured. SIRT1 and SIRT3 protein levels were determined by using ELISA. The genetic variants of SIRT1 rs3758391T>C, and SIRT3 rs185277566C>G, were detected by polymerase chain reaction-restriction fragment length (PCR-RFLP) technique. Malondialdehyde (MDA) level and the percentage of DNA fragmentation were higher in infertile samples, but serum levels of SIRT1 and SIRT3, and SOD activity was lower in infertile compared to fertile samples (P<0.001). The TC+CC genotypes and the C allele from SIRT1 rs3758391T>C polymorphism, and CG+GG genotypes and the G allele from SIRT3 rs185277566C>G polymorphism could increase risk of infertility (P<0.05). The results of this study suggest that war toxins through the impact on genotypes, decreasing levels of SIRT1 and SIRT3 and increasing levels of oxidative stress, lead to defects in the concentration, motility and morphology of sperms and thus, infertility in men.

Yerba mate consumption by ovariectomized rats alters white adipose tissue

IntroductionMenopause and post-menopause are characterized by low levels of estrogen that can be associated with the emergence of metabolic diseases. While hormone replacement therapy can alleviate many symptoms, it can also exacerbate other diseases such as breast cancer. In the search for natural alternatives, Ilex paraguariensis (Yerba Mate) has been identified as a potential therapy for the onset of obesity. Here, the effect of MATE consumption on white adipose tissue (WAT) was studied in ovariectomized rats, an animal model for post-menopause hormone loss. MethodsFour groups of animals were used: ovariectomy with MATE (OVX MATE) and without MATE (OVX), as well as sham surgery with MATE (Sham MATE) and without MATE (Sham). MATE was provided by gavage at 1 g/kg of body weight for eight weeks before measuring biochemical parameters in plasma and characterizing WAT morphology. ResultsThe consumption of Yerba MATE significantly decreased weight gain in ovariectomized rats and presented near control levels of triglycerides, total cholesterol, and LDL. A morphometric analysis of WAT showed a significant decrease in the area occupied by adipocytes in the group that consumed MATE. Finally, MATE consumption increased the UCP1 content in the WAT of the ovariectomized group. Yerba MATE treatment was also associated with higher levels of SIRT1 protein. ConclusionMATE consumption has a preventive effect on the weight gain observed in ovariectomized rats and potential benefits in naturally avoiding the onset of obesity post menopause.

The involvement and therapeutic potential of lncRNA Kcnq1ot1/miR-34a-5p/Sirt1 pathway in arsenic trioxide-induced cardiotoxicity

Background/AimsArsenic trioxide (ATO) is the first-line therapeutic drug for acute promyelocytic leukemia. However, the cardiotoxicity of ATO limits its clinical application. This study aims to explore the long noncoding RNA (lncRNA) involved molecular mechanism in ATO-induced cardiotoxicity and to identify available prevention strategies.MethodsATO was administered to mice or primary cultured mouse cardiomyocytes. Small interfering RNA targeting lncRNA Kcnq1ot1 (si-Kcnq1ot1) was used to knockdown lncRNA Kcnq1ot1. MiR-34a-5p mimic and antisense morpholino oligonucleotide targeting miR-34a-5p (AMO-34a-5p) were used to upregulate and downregulate the expression of miR-34a-5p, respectively. TUNEL staining was conducted to detect cell DNA damage. Flow cytometry assay was used to detect cell apoptosis. Western blot was conducted to detect Bcl-2, Bax and Sirt1 protein expression. Real-time PCR was used to detect lncRNA Kcnq1ot1, miR-34a-5p, and Sirt1 mRNA expression. Dual-luciferase reporter assay was performed to validate the predicted binding site.ResultsATO induced apoptosis in cardiomyocytes both in vivo and in vitro. Simultaneously, the expression of lncRNA Kcnq1ot1 and Sirt1 was downregulated, and miR-34a-5p was upregulated. MiR-34a-5p has binding sites with lncRNA Kcnq1ot1 and Sirt1. Knockdown of lncRNA Kcnq1ot1 induced apoptosis of cardiomyocytes, with increased miR-34a-5p and decreased Sirt1 expression. Inhibition of miR-34a-5p attenuated si-Kcnq1ot1-induced apoptosis in cardiomyocytes. Therefore, the lncRNA Kcnq1ot1/miR-34a-5p/Sirt1 signaling pathway is involved in ATO-induced cardiotoxicity. Propranolol alleviated ATO-induced apoptosis in cardiomyocytes both in vivo and in vitro, which was related to the lncRNA Kcnq1ot1/miR-34a-5p/Sirt1 signaling pathway.ConclusionThe lncRNA Kcnq1ot1/miR-34a-5p/Sirt1 pathway is involved in ATO-induced cardiotoxicity. Propranolol can attenuate ATO-induced cardiotoxicity at least partially through the lncRNA Kcnq1ot1/miR-34a-5p/Sirt1 pathway. Combined administration with propranolol may be a new strategy for alleviating the cardiotoxicity of ATO.

Modulating Morphological and Redox/Glycative Alterations in the PCOS Uterus: Effects of Carnitines in PCOS Mice

(1) Background: Polycystic ovarian syndrome (PCOS) is a common and multifactorial disease affecting reproductive-age women. Although PCOS ovarian and metabolic features have received extensive research, uterine dysfunction has been poorly investigated. This research aims to investigate morphological and molecular alterations in the PCOS uterus and search for modulating effects of different carnitine formulations. (2) Methods: CD1 mice were administered or not with dehydroepiandrosterone (DHEA, 6 mg/100 g body weight) for 20 days, alone or with 0.40 mg L-carnitine (LC) and 0.20 mg acetyl-L-carnitine (ALC) in the presence or absence of 0.08 mg propionyl-L-carnitine (PLC). Uterine horns from the four groups were subjected to histology, immunohistochemistry and immunoblotting analyses to evaluate their morphology, collagen deposition, autophagy and steroidogenesis. Oxidative-/methylglyoxal (MG)-dependent damage was investigated along with the effects on the mitochondria, SIRT1, SOD2, RAGE and GLO1 proteins. (3) Results: The PCOS uterus suffers from tissue and oxidative alterations associated with MG-AGE accumulation. LC-ALC administration alleviated PCOS uterine tissue alterations and molecular damage. The presence of PLC prevented fibrosis and maintained mitochondria content. (4) Conclusions: The present results provide evidence for oxidative and glycative damage as the main factors contributing to PCOS uterine alterations and include the uterus in the spectrum of action of carnitines on the PCOS phenotype.

Proteomic profiling reveals the potential mechanisms and regulatory targets of sirtuin 4 in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced Parkinson's mouse model.

Parkinson's disease (PD), as a common neurodegenerative disease, currently has no effective therapeutic approaches to delay or stop its progression. There is an urgent need to further define its pathogenesis and develop new therapeutic targets. An increasing number of studies have shown that members of the sirtuin (SIRT) family are differentially involved in neurodegenerative diseases, indicating their potential to serve as targets in therapeutic strategies. Mitochondrial SIRT4 possesses multiple enzymatic activities, such as deacetylase, ADP ribosyltransferase, lipoamidase, and deacylase activities, and exhibits different enzymatic activities and target substrates in different tissues and cells; thus, mitochondrial SIRT4 plays an integral role in regulating metabolism. However, the role and mechanism of SIRT4 in PD are not fully understood. This study aimed to investigate the potential mechanism and possible regulatory targets of SIRT4 in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mice. The expression of the SIRT4 protein in the MPTP-induced PD mouse mice or key familial Parkinson disease protein 7 knockout (DJ-1 KO) rat was compared against the control group by western blot assay. Afterwards, quantitative proteomics and bioinformatics analyses were performed to identify altered proteins in the vitro model and reveal the possible functional role of SIRT4. The most promising molecular target of SIRT4 were screened and validated by viral transfection, western blot assay and reverse transcription quantitative PCR (RT-qPCR) assays. The expression of the SIRT4 protein was found to be altered both in the MPTP-induced PD mouse mice and DJ-1KO rats. Following the viral transfection of SIRT4, a quantitative proteomics analysis identified 5,094 altered proteins in the vitro model, including 213 significantly upregulated proteins and 222 significantly downregulated proteins. The results from bioinformatics analyses indicated that SIRT4 mainly affected the ribosomal pathway, propionate metabolism pathway, peroxisome proliferator-activated receptor (PPAR) signaling pathway and peroxisome pathway in cells, and we screened 25 potential molecular targets. Finally, only fatty acid binding protein 4 (FABP4) in the PPAR signaling pathway was regulated by SIRT4 among the 25 molecules. Importantly, the alterations in FABP4 and PPARγ were verified in the MPTP-induced PD mouse model. Our results indicated that FABP4 in the PPAR signaling pathway is the most promising molecular target of SIRT4 in an MPTP-induced mouse model and revealed the possible functional role of SIRT4. This study provides a reference for future drug development and mechanism research with SIRT4 as a target or biomarker.

The Adipokine Visfatin Modulates Cancer Stem Cell Properties in Triple-Negative Breast Cancer

Obesity is a cancer progression risk factor; excessive adipocytes increase adipokine secretion. Visfatin, a novel adipokine highly expressed in cancer patients, is related to breast cancer risk. The modulation of nicotinamide adenine dinucleotide (NAD+) metabolism and the induction of a tumorigenic environment plays a vital role in cancer progression. Among cancer cell types, cancer stem-like cells (CSCs) with self-renewal and chemotherapy-resistance abilities could modulate tumor progression and cancer recurrence ability. In this study, we focused on visfatin's modulation effect on stemness-related properties using the high-malignancy breast cancer cell line MDA-MB-231 in in vitro and in vivo studies. Visfatin treatment significantly increased both the sphere number and sphere diameter and increased the protein expression of NANOG homeobox (NANOG), sex-determining region Y-box 2 (SOX2), and octamer-binding transcription factor 4 (OCT4), as well as SIRT1 protein levels. The serum angiogenesis marker VEGF and extracellular nicotinamide phosphoribosyl transferase (NAMPT, visfatin) were induced after visfatin treatment, increasing the stemness and angiogenesis environment, which were significantly reduced by the visfatin inhibitor FK866. Our results demonstrate that the visfatin-activated SIRT-SOX2 axis promotes triple-negative breast cancer stemness and enriches the tumorigenic microenvironment.

Synthesis and Biological Evaluation of a Series of Quinoline‐Based Quinazolinones and Carbamic Anhydride Derivatives

AbstractQuinoline‐based compounds are one of the most important classes of N‐heterocyclics exhibiting a wide spectrum of biological activities. There is a constant demand for the synthesis of new quinoline‐based molecules suitable for therapeutic applications. Here a new strategy is developed to synthesize different quinoline‐based quinazolinones catalytically using InCl3 through a cyclocondensation reaction of isatoic anhydride and aniline with 2‐substituted‐quinoline‐3‐carbaldehyde to produce 2‐(2‐phenoxyquinolin‐3‐yl)‐3‐phenyl‐2,3‐ dihydroquinazolin‐4(1H)‐one derivatives (&gt;90 % yields). In contrast, the reduced electrophilicity at the metal center allows the hydrazide ligand to bind In(III) and serendipitously forms benzoic(2‐phenoxyquinoline‐3‐carbonyl) carbamic anhydride (∼70 % yields). The mechanistic aspects of these reactions were rationally explained. The structure and purity of all the isolated derivatives were assessed by spectroscopic and analytical data. In view of a strong correlation existing between inflammation and cancer progression, the ex‐vivo anti‐inflammatory effect of the ligands was established. The anti‐cancer property of the proposed ligand was delineated with a specific SIRT protein family. Further, the computational docking studies on the binding abilities of 22 synthesized compounds with the Sirt1 protein were discussed in detail.

Muscle FOXO-Specific Overexpression and Endurance Exercise Protect Skeletal Muscle and Heart from Defects Caused by a High-Fat Diet in Young Drosophila.

Obesity appears to significantly reduce physical activity, but it remains unclear whether this is related to obesity-induced damage to skeletal muscle (SM) and heart muscle (HM). Endurance exercise (EE) reduces obesity-induced defects in SM and HM, but its molecular mechanism is poorly understood. The UAS/GAL4 system was used to construct the regulation of SM-specific FOXO gene expression in Drosophila, and the transgenic drosophila was subjected to EE and high-fat diet (HFD) intervention. The structure and function of SM and HM were impaired by a HFD and muscle-FOXO-specific RNAi (MFSR), including reduced climbing speed and climbing endurance, reduced fractional shortening of the heart, damaged myofibrils, and reduced mitochondria in HM. Besides, a HFD and MFSR increased triglyceride level and malondialdehyde level, decreased the Sirt1 and FOXO protein level, and reduced carnitine palmityl transferase I, superoxide dismutase, and catalase activity level, and they dow-regulated FOXO and bmm expression level in SM and HM. On the contrary, both muscle FOXO-specific overexpression (MFSO) and EE prevented abnormal changes of SM and HM in function, structure, or physiology caused by HFD and MFSR. Besides, EE also prevented defects of SM and HM induced by MFSR. Current findings confirmed MFSO and EE protected SM and heart from defects caused by a HFD via enhancing FOXO-realated antioxidant pathways and lipid catabolism. FOXO played a vital role in regulating HFD-induced defects in SM and HM, but FOXO was not a key regulatory gene of EE against damages in SM and HM. The mechanism was related to activity of Sirt1/FOXO/SOD (superoxide dismutase), CAT (catalase) pathways and lipid catabolism in SM and HM.