SIRT1 Expression Research Articles

Molecular crosstalk and putative mechanisms underlying mitochondrial quality control: The hidden link with methylmercury-induced cognitive impairment

Methylmercury (MeHg) is a neurotoxin associated with foetal neurodevelopmental and adult cognitive deficits. Neurons are highly dependent on the tricarboxylic acid cycle and oxidative phosphorylation to produce ATP and meet their high energy demands. Therefore, mitochondrial quality control (MQC) is critical for neuronal homeostasis. While existing studies have generated a wealth of data on the toxicity of MeHg, the complex cascades and molecular pathways governing the mitochondrial network remain to be elucidated. Here, 0.6, 1.2 and 2.4 mg/kg body weight of MeHg were administered intragastrically to pregnant Sprague Dawley rats to model maternal MeHg exposure. The results of the in vivo study revealed that MeHg-treated rats tended to perform more directionless repetitive strategies in the Morris Water Maze and fewer target-orientation strategies than control offspring. Moreover, pathological injury and synaptic toxicity were observed in the hippocampus. Transmission electron microscopy (TEM) demonstrated that the autophagosomes encapsulated damaged mitochondria, while showing a typical mitochondrial fission phenotype, which was supported by the activation of PINK1-dependent key regulators of mitophagy. Moreover, there was upregulation of DRP1 and FIS1. Additionally, MeHg compensation promoted mitochondrial biogenesis, as evidenced by the activation of the mitochondrial PGC1-α-NRF1-TFAM signalling pathway. Notably, SIRT3/AMPK was activated by MeHg, and the expression and activity of p-AMPK, p-LKB1 and SIRT3 were consistently coordinated. Collectively, these findings provide new insights into the potential molecular mechanisms regulating MeHg-induced cognitive deficits through SIRT3/AMPK MQC network coordination.

Plasma levels of Sirtuin 7 are decreased in patients with essential hypertension

BackgroundSirtuin 7 (SIRT7), as a nicotinamide adenine dinucleotide-dependent protein/histone deacetylase, has been implicated in the pathogenesis of cardiovascular diseases. However, whether SIRT7 is related to hypertension remains largely unclear. Thus, this study aims to explore the effects and correlation between SIRT7 and hypertension. MethodsA total of 72 patients with essential hypertension and 82 controls with non-hypertension were recruited at Beijing Tongren Hospital Affiliated with Capital Medical University from July 2022 to June 2023. Plasma SIRT7 expression was measured using enzyme-linked immunosorbent assay analysis. Clinical baseline characteristics, laboratory measurements, echocardiographic data, and medical therapy were collected. ResultsPlasma levels of SIRT7 were lower in hypertensive patients compared with non-hypertensive patients [0.97 (0.58–1.30) vs. 1.24 (0.99–1.46) ng/mL, P < 0.001, respectively]. Furthermore, compared with the low SIRT7 group, there were lower levels of systolic blood pressure, hyperlipidemia, and the ultrasonic electrocardiogram parameters left ventricular end-diastolic diameter and left atrial in diastole in the high SIRT7 group (P < 0.05, respectively). More importantly, multivariate logistic regression analyses indicated that plasma SIRT7 was a predictor of hypertension [OR: 0.06, 95 % CI (0.02–0.19), P < 0.001]. Receiver operating characteristics curve analysis revealed that the optimal cutoff value for plasma SIRT7 levels in detecting hypertension was determined as 0.85 ng/mL with a sensitivity of 73.6 % and a specificity of 89.0 %. The area under the curve for SIRT7 was 0.821 (95 % CI, 0.751–0.878; P < 0.001). ConclusionPlasma levels of SIRT7 are decreased in patients with essential hypertension, implying its potential as a biomarker for diagnosing essential hypertension..

Electroacupuncture improves peripheral neuropathy by up-regulating Sirt1/PGC-1α/TFAM pathway in type 2 diabetes rats with peripheral neuropathy.

To observe the effect of electroacupuncture (EA) on activation of silent information regulator 1 (Sirt1)/peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α)/mitochondrial transcription factor A (TFAM) pathway in type 2 diabetes (T2DM) rats with peripheral neuropathy (DPN) , so as to explore its possible mechanisms underlying improvement of DPN. Thirty male SD rats were randomly divided into blank control group (n=8) and DPN model group (n=22) which were further divided into model group (n=8) and EA group (n=8) after successful modeling. The model of T2DM was established by high-fat diet and low-dose intraperitoneal injection of streptozocin (35 mg/kg). For rats of the EA group (anesthetized with isoflurane), EA stimulation (2 Hz/15 Hz, 2 mA) was applied to "Tianshu"(ST25) for 20 min, once daily, 6 times a week for 6 weeks. The blood glucose level, body weight, area under curve (AUC) of glucose tolerance test, and hind-paw mechanical pain threshold and thermal pain threshold were observed. The intra-epidermal nerve fiber density (IENFD) of the hind-foot pad was observed by immunofluorescence staining. The motor nerve conduction velocity (MNCV) of the sciatic nerve was measured by using electrophysiological method. H.E. staining was used to observe the histopathological changes of the sciatic nerve after modeling. Transmission electron microscopy (TEM) was used to observe the ultrastructural changes of the sciatic nerve. The protein expressions of energy-related Sirt1, PGC-1α and TFAM in the sciatic nerve was detected by Western blot. Compared with the blank control group, the model group had a higher blood glucose contents and AUC (P<0.001), a slower MNCV (P<0.01), and a decrease in the body weight and in the mechanical and thermal pain thresholds (P<0.001) and IENFD (P<0.001), and in the expression levels of Sirt1, PGC-1α and TFAM (P<0.05, P<0.01). In contrast to the model group, the EA group had a decrease in the blood glucose contents and AUC (P<0.05, P<0.01), and an increase in mechanical and thermal pain thresholds, MNCV, IENFD, and expression levels of Sirt1, PGC-1α and TFAM proteins (P<0.01, P<0.05). In addition, results of histopathological and ultrastructural changes of the sciatic nerve showed more fragmented and disordered distribution of axons on the transverse section, and extensive separation of myelin and axons, uneven myelin thickness, axonal degeneration and irregular shape in the model group, whereas in the EA group, the axons on the transverse section were relatively more dense and more complete, the myelin sheath of the sciatic nerve was relatively uniform, and the axonal shape was relatively regular with relatively milder lesions. EA up-regulates the expressions of Sirt1, PGC-1α, TFAM in T2DM rats with DPN, which may be associated with its functions in improving and repairing the injured peripheral nerves in rats with DPN.

Mechanism of ameliorating cerebral ischemia/reperfusion injury by antioxidant inhibition of autophagy based on network pharmacology and experimental verification.

Cerebral ischemia-reperfusion injury (CIRI) is one of the most difficult challenges in cerebrovascular disease research. It is primarily caused by excessive autophagy induced by oxidative stress. Previously, a novel compound X5 was found, and the excellent antioxidant activity of it was verified in this study. Moreover, network pharmacological analysis suggested that compound X5 was closely associated with autophagy and the mTOR pathway. In vitro, X5 could significantly inhibit the expression of autophagy proteins Beclin-1 and LC3-β, which are induced by H2O2, and promote the expression of SIRT1. In vivo, compound X5 significantly reduced the infarct size and improved the neurological function scores in the middle cerebral artery occlusion (MCAO) model of rats. In conclusion, ROS-induced autophagy is closely related to mTOR, SIRT1 and others, and X5 holds promise as a candidate for the treatment of CIRI.

Dulaglutide restores endothelial progenitor cell levels in diabetic mice and mitigates high glucose-induced endothelial injury through SIRT1-mediated mitochondrial fission

Type 2 diabetes mellitus (T2DM) significantly impairs the functionality and number of endothelial progenitor cells (EPCs) and resident endothelial cells, critical for vascular repair and regeneration, exacerbating the risk of vascular complications. GLP-1 receptor agonists, like dulaglutide, have emerged as promising therapeutic agents due to their multifaceted effects, including the enhancement of EPC activity and protection of endothelial cells. This study investigates dulaglutide's effects on peripheral blood levels of CD34+ and CD133+ cells in a mouse model of lower limb ischemia and its protective mechanisms against high-glucose-induced damage in endothelial cells. Results demonstrated that dulaglutide significantly improves blood flow, reduces tissue damage and inflammation in ischemic limbs, and enhances glycemic control. Furthermore, dulaglutide alleviated high-glucose-induced endothelial cell damage, evident from improved tube formation, reduced reactive oxygen species accumulation, and restored endothelial junction integrity. Mechanistically, dulaglutide mitigated mitochondrial fission in endothelial cells under high-glucose conditions, partly through maintaining SIRT1 expression, which is crucial for mitochondrial dynamics. This study reveals the potential of dulaglutide as a therapeutic option for vascular complications in T2DM patients, highlighting its role in improving endothelial function and mitochondrial integrity.

Pu-erh tea theabrownin improves the ovarian function and gut microbiota in laying hens

Studies have reported that theabrownin can moderate the lipid metabolism and intestinal microbiota, thereby affecting the health of humans and model animals, however the research on laying hens is scarce. The present study aimed to investigate the effects of dietary theabrownin supplementation on lipid metabolism, microbial composition and ovarian function in laying hens. A total of 80 laying hens (25 wk of age) were fed with normal diet (CON) and normal diet +100 mg/kg theabrownin (PT group) for 12 wk. The results showed that the addition of theabrownin enhanced villus height of duodenum and decreased crypt depth of jejunum (P < 0.05). At the same time, compared with CON, the concentration of IL-6 and the mRNA expression of IL-1β and IL-6 were decreased significantly in PT group (P < 0.05). Dietary theabrownin reduced the concentration of total cholesterol and glycerol, while decreased lipid droplet optical density in liver (P < 0.05). Compared with CON group, the mRNA expression of PPARγ, HMG-CoAS, ACC were down-regulated and the mRNA expression of CYP8B1 was up-regulated in PT group (P < 0.05). The ACE, Chao1 and Observed_species indexes in cecum microbiota were increased by PT group intervention (P < 0.05). Dietary PT supplementation enhanced the relative abundance of Firmicutes (phylum), Lactobacillus (genus) and the Firmicutes to Bacteroidetes ratio, and reduced the relative abundance of Bacteroidetes (phylum) in cecum (P < 0.05). The organic acids and its derivatives were up-regulated by theabrownin intervention in serum metabolites (P < 0.05). Dietary theabrownin supplementation resulted in higher mRNA expression of Bcl-2 and SIRT1 in ovary and increased the concentration of estradiol in serum (P < 0.05). These discovering indicated that dietary theabrownin supplementation enhanced the intestinal function and influenced serum metabolism by improving intestinal morphology, microbiota community structure and reducing the concentration and expression of inflammatory cytokines in intestine. Dietary theabrownin reduced hepatic lipid deposition and it also decreased the cell apoptosis rate to improve ovarian function and egg weight which were associated with the SIRT1 pathway.

Effect of MEHP on testosterone synthesis via Sirt1/Foxo1/Rab7 signaling pathway inhibition of lipophagy in TM3 cells

Mono-2-ethylhexyl phthalic acid (MEHP) is the most toxic metabolite of the plasticizer di-2-ethylhexyl phthalic acid (DEHP), and studies have shown that MEHP causes serious reproductive effects. However, its exact mechanisms of action remain elusive. In this study, we aimed to investigate the reproductive effects of MEHP and preliminarily explore its underlying molecular mechanisms. We found that TM3 cells gradually secreted less testosterone and intracellular free cholesterol with increasing MEHP exposure. MEHP exposure inhibited lipophagy and the Sirt1/Foxo1/Rab7 signaling pathway in TM3 cells, causing aberrant accumulation of intracellular lipid droplets. Addition of the Sirt1 agonist SRT1720 and Rab7 agonist ML-098 alleviated the inhibition of lipophagy and increased free cholesterol and testosterone contents in TM3 cells. SRT1720 alleviated the inhibitory effect of MEHP on the Sirt1/Foxo1/Rab7 signaling pathway, whereas ML-098 only alleviated the inhibition of Rab7 protein expression by MEHP and had no effect on Sirt1 and Foxo1 protein expression. This suggests that MEHP inhibits lipophagy in TM3 cells by suppressing the Sirt1/Foxo1/Rab7 signaling pathway, ultimately leading to a further decrease in cellular testosterone secretion. This study improves our current understanding of the toxicity and molecular mechanisms of action of MEHP and provides new insights into the reproductive effects of phthalic acid esters.

Semaglutide attenuates pathological electrophysiological remodeling in diabetic cardiomyopathy via restoring Cx43 expression.

Semaglutide is a relatively new anti-hyperglycemic agent that was shown to carry cardioprotective potentials. However, the exact effects of semaglutide on diabetic cardiomyopathy (DCM) and their underlining mechanism remain unclear. This study aimed to evaluate the effects of semaglutide on myocardium injury and cardiac function in DCM mice and its potential mechanisms, with emphasis on its effects on Cx43 and electrophysiological remodeling. C57BL/6 mice were randomly divided into four groups: control group, semaglutide group, diabetes group, and diabetes + semaglutide treatment group. Type 1 diabetes were induced by intraperitoneal injection of streptozotocin. Mice in the semaglutide intervention group were injected subcutaneously with semaglutide (0.15 mg/kg) every week for 8 weeks. The blood glucose, cardiac function, oxidative stress markers, apoptosis, expression of Sirt1, AMPK, Cx43, and electrocardiogram of mice in each group were evaluated. Treatment with semaglutide alleviated glucose metabolism disorders and improved cardiac dysfunction in diabetic mice. In addition, semaglutide ameliorated the increase in oxidative stress and apoptosis in diabetic heart. Sirt1/AMPK pathway was activated after semaglutide treatment. Furthermore, diabetic mice showed reduced expression of Cx43 in the myocardium, accompanied by changes in electrocardiogram, including significantly prolonged RR, QRS, QT and QTc interval. Semaglutide treatment restored Cx43 expression and reversed the above-mentioned ECG abnormalities. Our research results showed that semaglutide protected against oxidative stress and apoptosis in diabetic heart, thereby improving cardiac function and electrophysiological remodelling in DCM mice, which may attribute to activation of Sirt1/AMPK pathway and restore of Cx43 expression.

Hepatic Sirt6 activation abrogates acute liver failure.

Acute liver failure (ALF) is a deadly illness due to insufficient detoxification in liver induced by drugs, toxins, and other etiologies, and the effective treatment for ALF is very limited. Among the drug-induced ALF, acetaminophen (APAP) overdose is the most common cause. However, the molecular mechanisms underlying APAP hepatoxicity remain incompletely understood. Sirtuin 6 (Sirt6) is a stress responsive protein deacetylase and plays an important role in regulation of DNA repair, genomic stability, oxidative stress, and inflammation. Here, we report that genetic and pharmacological activation of Sirt6 protects against ALF in mice. We first observed that Sirt6 expression was significantly reduced in the liver tissues of human patients with ALF and mice treated with an overdose of APAP. Then we developed an inducible Sirt6 transgenic mice for Cre-mediated overexpression of the human Sirt6 gene in systemic (Sirt6-Tg) and hepatic-specific (Sirt6-HepTg) manners. Both Sirt6-Tg mice and Sirt6-HepTg mice exhibited the significant protection against APAP hepatoxicity. In contrast, hepatic-specific Sirt6 knockout mice exaggerated APAP-induced liver damages. Mechanistically, Sirt6 attenuated APAP-induced hepatocyte necrosis and apoptosis through downregulation of oxidative stress, inflammation, the stress-activated kinase JNK activation, and apoptotic caspase activation. Moreover, Sirt6 negatively modulated the level and activity of poly (ADP-ribose) polymerase 1 (PARP1) in APAP-treated mouse liver tissues. Importantly, the specific Sirt6 activator MDL-800 exhibited better therapeutic potential for APAP hepatoxicity than the current drug acetylcysteine. Furthermore, in the model of bile duct ligation induced ALF, hepatic Sirt6-KO exacerbated, but Sirt6-HepTg mitigated liver damage. Collectively, our results demonstrate that Sirt6 protects against ALF and suggest that targeting Sirt6 activation could be a new therapeutic strategy to alleviate ALF.

Podophyllotoxin via SIRT1/PPAR /NF-κB axis induced cardiac injury in rats based on the toxicological evidence chain (TEC) concept

BackgroundThe study of cardiotoxicity of drugs has become an important part of clinical safety evaluation of drugs. It is commonly known that podophyllotoxin (PPT) and its many derivatives and congeners are broad-spectrum pharmacologically active substances. Clinical cardiotoxicity of PPT and its derivatives has been raised, basic research on the mechanism of cardiotoxicity remains insufficient. PurposeIn present study, our group's innovative concept of toxicological evidence chain (TEC) was applied to reveal the cardiac toxicity mechanism of PPT by targeted metabolomics, TMT-based quantitative proteomics and western blot. MethodsThe injury phenotype evidence (IPE) acquired from the toxicity manifestations, such as weight and behavior observation of Sprague-Dawley rat. The damage to rat hearts were assessed through histopathological examination and myocardial enzymes levels, which were defined as Adverse Outcomes Evidence (AOE). The damage to rat hearts was assessed through histopathological examination and myocardial enzyme levels, which were defined as evidence of adverse outcomes.Overall measurements of targeted metabolomics based on energy metabolism and TMT-based quantitative proteomics were obtained after exposure to PPT to acquire the Toxic Event Evidence (TEE). The mechanism of cardiac toxicity was speculated based on the integrated analysis of targeted metabolomics and TMT-based quantitative proteomics, which was verified by western blot. ResultsThe results indicated that exposure to PPT could result in significant elevation of myocardial enzymes and pathological alterations in rat hearts. In addition, we found that PPT caused disorders in cardiac energy metabolism, characterized by a decrease in energy metabolism fuels. TMT-based quantitative proteomics revealed that the PPAR (Peroxisome proliferators-activated receptor) signaling pathway needs further study. It is worth noting that PPT may suppress the expression of SIRT1, subsequently inhibiting AMPK, decreasing the expression of PGC-1α, PPARα and PPARγ. This results in disorders of glucose oxidation, glycolysis and ketone body metabolism. Additionally, the increase in the expression of p-IKK and p-IκBα, leads to the nuclear translocation of NF-κB p65 from the cytosol, thus triggering inflammation. ConclusionThis study comprehensively evaluated cardiac toxicity of PPT and initially revealed the mechanism of cardiotoxicity,suggesting that PPT induced disorders of energy metabolism and inflammation via SIRT1/PPAR/NF-κB axis, potentially contributing to cardiac injury.

Jiawei Dachaihu decoction protects against mitochondrial dysfunction in atherosclerosis (AS) mice with chronic unpredictable mild stress (CUMS) via SIRT1/PGC-1α/TFAM/LON signaling pathway

Ethnopharmacological relevanceJiaWei DaChaiHu is composed of Bupleurum chinense, Scutellaria baicalensis, Pinellia ternata, Paeonia lactiflora, Zingiber officinaleRoscoe, Poncirus tuifoliata, Rheum palmatum L., Curcumae Radix, Herba Lysimachiae, Ziziphus. JiaWei DaChaiHu is one of the most common traditional Chinese medicines for the treatment of depression. Aim of the studyThe chronic unpredictable mild stress (CUMS) has been shown to promote atherosclerosis (AS). Dachaihu has been widely used in traditional Chinese medicine and has been known to exert distinct pharmacological effects. This investigation aims to examine the therapeutic effect of Jiawei Dachaihu extract on AS animal models with CUMS. MethodsAS-CUMS mice model was established by Apoe−/− mice. Mice were treated with Jiawei Dachaihu. Serum total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL-C), high-density lipoprotein (HDL-C) levels were measured using ELISA kits. Aortic tissue pathologic changes detected by oil red O staining. Mice behavioral changes detected by sucrose preference test and sucrose preference test. The relative mRNA expression levels of CRH, ND1, and TFAM were determined by qRT-PCR. 5-HT1A, BDNF, LON, TFAM, PGC-1α, and SIRT1 protein expression determined by western blotting. ATP content detected by ATP kits. ResultsThe treatment with Jiawei Dachaihu extract alleviated the veins plaque and reduced stress signs in vitro and in vivo. It increased the ATP and HDL-C levels while decreased the TC, TG, LDL-C levels. Jiawei Dachaihu extract treatment upregulated Lon, SIRT1, TFAM, PGC-1α, BDNF, and 5-HT1A protein expression and regained mitochondrial function. ConclusionJiawei Dachaihu extract could alleviate AS and reduce CUMS by upregulating the SIRT1/PGC-1α signaling and promoted its crosstalk with Lon protein to maintain mitochondrial stability.

Esculin suppresses the PERK-eIF2α-CHOP pathway by enhancing SIRT1 expression in oxidative stress-induced rat chondrocytes, mitigating osteoarthritis progression in a rat model

ObjectiveOsteoarthritis (OA) is a degenerative disease characterized by the gradual degeneration of chondrocytes, involving endoplasmic reticulum (ER) stress. Esculin is a natural compound with antioxidant, anti-inflammatory and anti-tumor properties. However, its impact on ER stress in OA therapy has not been thoroughly investigated. We aim to determine the efficiency of Esculin in OA treatment and its underlying mechanism. MethodsWe utilized the tert-butyl hydroperoxide (TBHP) to establish OA model in chondrocytes. The expression of SIRT1, PERK/eIF2α pathway-related proteins, apoptosis-associated proteins and ER stress-related proteins were detected by Western blot and Real-time PCR. The apoptosis was evaluated by flow cytometry and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) staining. X-ray imaging, Hematoxylin & Eosin staining, Safranin O staining and immunohistochemistry were used to assess the pharmacological effects of Esculin in the anterior cruciate ligament transection (ACLT) rat OA model. ResultsEsculin downregulated the expression of PERK/eIF2α pathway-related proteins, apoptosis-associated proteins and ER stress-related proteins, while upregulated the expression of SIRT1 and Bcl2 in the TBHP-induced OA model in vitro. It was coincident with the results of TUNEL staining and flow cytometry. We further confirmed the protective effect of Esculin in the rat ACLT-related model. ConclusionOur results suggest the potential therapeutic value of Esculin on osteoarthritis. It probably inhibits the PERK-eIF2α-ATF4-CHOP pathway by upregulating SIRT1, thereby mitigating endoplasmic reticulum stress and protecting chondrocytes from apoptosis.

The SP1/SIRT1/ACLY signaling axis mediates fatty acid oxidation in renal ischemia–reperfusion-induced renal fibrosis

BackgroundRenal ischemia–reperfusion is the primary cause of acute kidney injury (AKI). Clinically, most patients who experience ischemia–reperfusion injury eventually progress gradually to renal fibrosis and chronic kidney disease (CKD). However, the underlying mechanism for AKI to CKD transition remain absent. Our study demonstrated that the downregulation of sirtuin 1 (Sirt1)-mediated fatty acid oxidation (FAO) facilitates IRI-induced renal fibrosis. MethodsThe IRI animal model was established, and ribonucleic acid (RNA) sequencing was used to explore potential differentially expressed genes (DEGs) and pathways. The SIRT1 knockout mice were generated, and a recombinant adeno-associated virus that overexpresses SIRT1 was injected into mice to explore the function of SIRT1 in renal fibrosis induced by renal IRI. In vitro, hypoxia/reoxygenation (H/R) was used to establish the classical model of renal IRI and overexpression or knockdown of SIRT1 to investigate the SIRT1 function through lentiviral plasmids. The underlying molecular mechanism was explored through RNA sequencing, bioinformatics analysis, and chromatin immunoprecipitation assay. ResultsRNA sequencing analysis and western blot demonstrated that the expression of SIRT1 was significantly decreased in IRI mice. Overexpression of SIRT1 improved renal function and reduced lipid deposition and renal fibrosis. On the contrary, knockout of SIRT1 aggravated kidney injury and renal fibrosis. RNA sequencing, bioinformatics analysis, and chromatin immunoprecipitation assay mechanistically revealed that SIRT1 impairs the acetylation of histone H3K27 on the promoter region of ACLY, thereby impeding FAO activity and promoting renal fibrosis. Additionally, SP1 regulated FAO by directly modulating SIRT1 expression. ConclusionOur findings highlight that downregulation of SIRT1-modulated FAO facilitated by the SP1/SIRT1/ACLY axis in the kidney increases IRI, suggesting SIRT1 to be a potential therapeutic target for renal fibrosis induced by renal IRI.

SIRT1 alleviates Cd nephrotoxicity through NF-κB/p65 deacetylation–mediated pyroptosis in rat renal tubular epithelial cells

Cadmium (Cd) is a widely distributed environmental pollutant, primarily causing nephrotoxicity through renal proximal tubular cell impairment. Pyroptosis is an inflammation-related nucleotide-binding oligomerization segment-like receptor family 3 (NLRP3)-dependent pathway for programmed cell death. We previously reported that inappropriate inflammation caused by Cd is a major contributor to kidney injury. Therefore, research on Cd-induced inflammatory response and pyroptosis may clarify the mechanisms underlying Cd-induced nephrotoxicity. In this study, we observed that Cd-induced nephrotoxicity is associated with NLRP3 inflammasome activation, leading to an increase in proinflammatory cytokine expression and secretion, as well as pyroptosis-related gene upregulation, both in primary rat proximal tubular (rPT) cells and kidney tissue from Cd-treated rats. In vitro, these effects were significantly abrogated through siRNA-based Nlrp3 silencing; thus, Cd may trigger pyroptosis through an NLRP3 inflammasome–dependent pathway. Moreover, Cd exposure considerably elevated reactive oxygen species (ROS) content. N-acetyl-l-cysteine, an ROS scavenger, mitigated Cd-induced NLRP3 inflammasome activation and subsequent pyroptosis. Mechanistically, Cd hindered the expression and deacetylase activity of SIRT1, eventually leading to a decline in SIRT1–p65 interactions, followed by an elevation in acetylated p65 levels. The administration of resveratrol (a SIRT1 agonist) or overexpression of Sirt1 counteracted Cd-induced RELA/p65/NLRP3 pathway activation considerably, leading to pyroptosis. This is the first study to reveal significant contributions of SIRT1-triggered p65 deacetylation to pyroptosis and its protective effects against Cd-induced chronic kidney injury. Our results may aid in developing potential therapeutic strategies for preventing Cd-induced pyroptosis through SIRT1-mediated p65 deacetylation.

Linc01588 deletion inhibits the malignant biological characteristics of hydroquinone-induced leukemic cells via miR-9-5p/SIRT1

Leukemia caused by environmental chemical pollutants has attracted great attention, the malignant leukemic transformation model of TK6 cells induced by hydroquinone (HQ) has been previously found in our team. However, the type of leukemia corresponding to this malignant transformed cell line model needs further study and interpretation. Furthermore, the molecular mechanism of malignant proliferation of leukemic cells induced by HQ remains unclear. This study is the first to reveal the expression of aberrant genes in leukemic cells of HQ-induced malignant transformation, which may correspond to chronic lymphocytic leukemia (CLL). The expression of Linc01588, a long non-coding RNA (lncRNA), was significantly up-regulated in CLL patients and leukemic cell line model which previously described. After gain-of-function assays and loss-of-function assays, feeble cell viability, severe apoptotic phenotype and the increased secretion of TNF-α were easily observed in malignant leukemic TK6 cells with Linc01588 deletion after HQ intervention. The tumors derived from malignant TK6 cells with Linc01588 deletion inoculated subcutaneously in nude mice were smaller than controls. In CLL and its cell line model, the expression of Linc01588 and miR-9–5p, miR-9–5p and SIRT1 were negative correlation respectively in CLL and cell line model, while the expression of Linc01588 and SIRT1 were positive correlation. The dual-luciferase reporter assay showed that Linc01588 & miR-9–5p, miR-9–5p & SIRT1 could bind directly, respectively. Furthermore, knockdown of miR-9–5p successfully rescued the severe apoptotic phenotype and the increased secretion of TNF-α caused by the Linc01588 deletion, the deletion of Linc01588 in human CLL cell line MEC-2 could also inhibit malignant biological characteristics, and the phenotype caused by the deletion of Linc01588 could also be rescued after overexpression of SIRT1. Moreover, the regulation of SIRT1 expression in HQ19 cells by Linc01588 and miR-9–5 P may be related to the Akt/NF-κB pathway. In brief, Linc01588 deletion inhibits the malignant biological characteristics of HQ-induced leukemic cells via miR-9–5p/SIRT1, and it is a novel and hopeful clue for the clinical targeted therapy of CLL.

Pyrroloquinoline quinone promotes human mesenchymal stem cell-derived mitochondria to improve premature ovarian insufficiency in mice through the SIRT1/ATM/p53 pathway

BackgroundDNA damage and oxidative stress induced by chemotherapy are important factors in the onset of premature ovarian insufficiency (POI). Studies have shown that mitochondria derived from mesenchymal stem cells (MSC-Mito) are beneficial for age-related diseases, but their efficacy alone is limited. Pyrroloquinoline quinone (PQQ) is a potent antioxidant with significant antiaging and fertility enhancement effects. This study aimed to investigate the therapeutic effect of MSC-Mito in combination with PQQ on POI and the underlying mechanisms involved.MethodsA POI animal model was established in C57BL/6J mice by cyclophosphamide and busulfan. The effects of MSC-Mito and PQQ administration on the estrous cycle, ovarian pathological damage, sex hormone secretion, and oxidative stress in mice were evaluated using methods such as vaginal smears and ELISAs. Western blotting and immunohistochemistry were used to assess the expression of SIRT1, PGC-1α, and ATM/p53 pathway proteins in ovarian tissues. A cell model was constructed using KGN cells treated with phosphoramide mustard to investigate DNA damage and apoptosis through comet assays and flow cytometry. SIRT1 siRNA was transfected into KGN cells to further explore the role of the SIRT1/ATM/p53 pathway in combination therapy with MSC-Mito and PQQ for POI.ResultsThe combined treatment of MSC-Mito and PQQ significantly restored ovarian function and antioxidant capacity in mice with POI. This treatment also reduced the loss of follicles at various stages, improving the disrupted estrous cycle. In vitro experiments demonstrated that PQQ facilitated the proliferation of MitoTracker-labelled MSC-Mito, synergistically restoring mitochondrial function and inhibiting oxidative stress in combination with MSC-Mito. Both in vivo and in vitro, the combination of MSC-Mito and PQQ increased mitochondrial biogenesis mediated by SIRT1 and PGC-1α while inhibiting the activation of ATM and p53, consequently reducing DNA damage-mediated cell apoptosis. Furthermore, pretreatment of KGN cells with SIRT1 siRNA reversed nearly all the aforementioned changes induced by the combined treatment.ConclusionsOur research findings indicate that PQQ facilitates MSC-Mito proliferation and, in combination with MSC-Mito, ameliorates chemotherapy-induced POI through the SIRT1/ATM/p53 signaling pathway.

Inhibiting Pink1/Parkin-mediated mitophagy enhances the anticancer effects of quercetin in hepatocellular carcinomaf

Quercetin, a naturally occurring flavonoid, has been investigated for its potential anti-cancer effects in various types of cancer, including hepatocellular carcinoma (HCC). However, its suppressing effect on reactive oxygen species (ROS) production might limited its anti-cancer effects. In this study, we aimed to explore the interplay among quercetin, mitochondrial dynamics and mitophagy and whether mitophagy-inhibition synergistically enhances the anti-tumor effects of quercetin. Huh7 and Hep3B cells were utilized for in vitro and in vivo studies. Results showed that quercetin treatment significantly increased the expression of mitochondrial fusion genes (MFN1 and MFN2) and decreased the expression of fission genes (DRP1 and FIS1) in Huh7 and Hep3B cells, leading to a more fused and elongated mitochondrial network. Quercetin upregulated the expression of key mitophagy regulators, PINK1 and PARK2, and enhanced the colocalization of mitochondria with lysosomes, indicating increased mitophagy. Knockdown of PINK1, PARK2, or SIRT1 attenuated quercetin-induced mitophagy and reduction of intracellular ROS levels. Quercetin treatment upregulates SIRT1 expression, which subsequently enhances PINK1 and PARK2 expression in Huh7 and Hep3B cells. In vivo experiments using Hep3B xenograft models revealed that the combination of quercetin with the mitophagy inhibitor hydroxychloroquine or SIRT1 knockdown significantly enhanced the anticancer effects of quercetin, as evidenced by reduced tumor size and weight, increased necrosis and apoptosis, and decreased proliferation in tumor tissues. These findings suggest that quercetin-induced mitochondrial fusion and Pink1/Parkin-dependent mitophagy may negatively influence its anti-cancer effects in HCC. Targeting mitophagy may enhance the therapeutic potential of quercetin in HCC treatment.

Favorable osteogenic activity of vericiguat doped in β-tricalcium phosphate: In vitro and in vivo studies.

Recently, more and more studies have shown that guanylate cyclase, an enzyme that synthesizes cyclic guanosine monophosphate (cGMP), plays an important role in bone metabolism. Vericiguat (VIT), a novel oral soluble guanylate cyclase stimulator, directly generates cyclic guanosine monophosphate and reduce the death incidence from cardio-vascular causes or hospitalization. Recent studies have shown beneficial effects of VIT in animal models of osteoporosis, but very little is currently known about the effects of VIT on bone defects in the osteoporotic states. Therefore, in this study, β-tricalcium phosphate (β-TCP) was used as a carrier to explore the effect of local VIT administration on the repair of femoral metaphyseal bone defects in ovariectomized (OVX) rats. When MC3T3-E1 was cultured in the presence of H2H2, VIT, similar to Melatonin (MT), therapy could increase the matrix mineralization and ALP, SOD2, SIRT1, and OPG expression, reduce ROS and Mito SOX production, RANKL expression, Promote the recovery of mitochondrial membrane potential. In the OVX rat model, VIT increases the osteogenic effect of β-TCP and better results were obtained at a dose of 5mg. Local use of VIT can inhibit increased OC, BMP2 and RUNX2 expressions in bone tissue, while decreased SOST and TRAP expressions by RT-PCR and immunohistochemistry. Thereby, VIT stimulates bone regeneration and is a promising candidate for promoting bone repair in osteoporosis.

The phenylpropionamide extract of hemp (Cannabis sativa L.) seed improves learning memory ability and survival rate by attenuating microglia activation and reducing amyloid deposition via the SIRT1-AMAD10 pathway in APP/PS1 mice

BackgroundFructus cannabis (Hemp seed), the dried and mature fruit of Cannabis sativa L., was reported to have effects against Alzheimer's disease (AD) in different experimental models. However, either chemical composition or mechanisms of action was not clear. Our previous work isolated and identified diverse phenylpropionamides such as cannabisin A-F, caffeoyltyramine and feryroyltyramine from hemp seed, which showed antioxidant and anti-neuroinflammatory activity in cell models. PurposeTo study the anti-AD effect and mechanism of the total phenylpropionamides (TPA) extract from hemp seed using APPswe/PS1dE9 mice model. MethodsTPA extract was prepared via extraction and column chromatography techniques, then analyzed and measured using HPLC, HPLC-MS and Folin-Ciocalteu method. The extract was administered by gavage to APPswe/PS1dE9 mice. The learning memory ability of mice were examined using new object recognition test and Morris water maze. Hematoxylin and Eosin staining was used to observe the morphology of neuronal cells in the hippocampal region of brain tissue; ELISA was used to measure the content of IL-1β, TNF-α, IL-6, superoxide dismutase (SOD), malondialdehyde (MDA) in the brain tissue; the deposition of Aβ protein was measured by immunohistochemistry and Western blotting; the activation of microglia was measured by immunofluorescence. The expression of APP, PS1, SIRT1, and ADAM10 proteins was measured by Western blotting. ResultsFolin-Ciocalteu method showed the total phenylpropionamides content was 238.03 μg caffeic acid equivalent /mg TPA. HPLC and HPLC-MS analysis showed the contents of N-trans-caffeoyltyramine, cannabisin A and B were 20.16 μg/mg, 32.16 μg/mg and 214.35 μg/mg, respectively, in TPA extract. TPA treatment significantly increased the survival rate of APP/PS1 mice, improved the learning and memory ability, reversed the neural cell damage in the hippocampal region, and reduced Aβ deposition and activated microglia in brain tissue. Meanwhile, the administration decreased the neuroinflammatory factors TNF-α, IL-6, IL-1β expression, increased antioxidant enzyme SOD activity, and attenuated MDA expression. Western blotting showed that TPA administration increased SIRT1 and ADAM10 protein expression and decreased APP and PS1 protein expression. ConclusionTPA improved learning memory capacity, increased survival rate, attenuated neuroinflammation, oxidative stress, microglia activation and hippocampal apoptosis, and reduced amyloid deposition via the SIRT1-ADAM10 pathway in APP/PS1 mice.

Icariin attenuates vascular endothelial dysfunction by inhibiting inflammation through GPER/Sirt1/HMGB1 signaling pathway in type 1 diabetic rats

Icariin, a flavonoid glycoside, is extracted from Epimedium. This study aimed to investigate the vascular protective effects of icariin in type 1 diabetic rats by inhibiting high-mobility group box 1 (HMGB1)-related inflammation and exploring its potential mechanisms. The impact of icariin on vascular dysfunction was assessed in streptozotocin (STZ)-induced diabetic rats through vascular reactivity studies. Western blotting and immunofluorescence assays were performed to measure the expressions of target proteins. The release of HMGB1 and pro-inflammation cytokines were measured by enzyme-linked immunosorbent assay (ELISA). The results revealed that icariin administration enhanced acetylcholine-induced vasodilation in the aortas of diabetic rats. It also notably reduced the release of pro-inflammatory cytokines, including interleukin-8 (IL-8), IL-6, IL-1β, and tumor necrosis factor-alpha (TNF-α) in diabetic rats and high glucose (HG)-induced human umbilical vein endothelial cells (HUVECs). The results also unveiled that the pro-inflammatory cytokines in the culture medium of HUVECs could be increased by rHMGB1. The increased release of HMGB1 and upregulated expressions of HMGB1-related inflammatory factors, including advanced glycation end products (RAGE), Toll-like receptor 4 (TLR4), and phosphorylated p65 (p-p65) in diabetic rats and HG-induced HUVECs, were remarkably suppressed by icariin. Notably, HMGB1 translocation from the nucleus to the cytoplasm in HUVECs under HG was inhibited by icariin. Meanwhile, icariin could activate G protein-coupled estrogen receptor (GPER) and sirt1. To explore the role of GPER and Sirt1 in the inhibitory effect of icariin on HMGB1 release and HMGB-induced inflammation, GPER inhibitor and Sirt1 inhibitor were used in this study. These inhibitors diminished the effects of icariin on HMGB1 release and HMGB1-induced inflammation. Specifically, the GPER inhibitor also negated the activation of Sirt1 by icariin. These findings suggest that icariin activates GPER and increases the expression of Sirt1, which in turn reduces HMGB1 translocation and release, thereby improving vascular endothelial function in type 1 diabetic rats by inhibiting inflammation.