SIRT1 Pathway Research Articles

Circulating exosome-mediated AMPKα–SIRT1 pathway regulates lipid metabolism disorders in calf hepatocytes

Subclinical ketosis (SCK) in dairy cows is often misdiagnosed because it lacks clinical signs and detection indicators. However, it is highly prevalent and may transform into clinical ketosis if not treated promptly. Due to the negative energy balance, a large amount of fat is mobilized, producing NEFA that exceeds the upper limit of liver processing, which in turn leads to the disturbance of liver lipid metabolism. The silent information regulator 1 (SIRT1) is closely related to hepatic lipid metabolism disorders. Exosomes as signal transmitters, also play a role in the circulatory system. We hypothesize that the circulating exosome-mediated adenosine 5′-monophosphate (AMP)-activated protein kinase alpha (AMPKα)–SIRT1 pathway regulates lipid metabolism disorders in SCK cows. We extracted the exosomes required for the experiment from the peripheral circulating blood of non-ketotic (NK) and SCK cows. We investigated the effect of circulating exosomes on the expression levels of mRNA and protein of the AMPKα–SIRT1 pathway in non-esterified fatty acid (NEFA)-induced dairy cow primary hepatocytes using in vitro cell experiments. The results showed that circulating exosomes increased the expression levels of Lipolysis-related genes and proteins (AMPKα, SIRT1, and PGC-1α) in hepatocytes treated with 1.2 mM NEFA, and inhibited the expression of lipid synthesis-related genes and protein (SREBP-1C). The regulation of exosomes on lipid metabolism disorders caused by 1.2 mM NEFA treatment showed the same trend as for SIRT1-overexpressing adenovirus. The added exosomes could regulate NEFA-induced lipid metabolism in hepatocytes by mediating the AMPKα–SIRT1 pathway, consistent with the effect of transfected SIRT1 adenovirus.

Nicotinamide mononucleotide based hyaluronic acid methacryloyl hybrid hydrogel regulating stem cells fate for bone regeneration via SIRT1/RUNX2 signaling

Efficient bone reconstruction, especially of the critical size after bone damage, remains a challenge in the clinic. Bone marrow mesenchymal stem cell (BMSC) osteogenic differentiation is considered as a promising strategy for bone repair. Nicotinamide adenine dinucleotide (NAD+) regulating BMSC fate and cellular function enhance osteogenesis, but is hardly delivered and lack of targeting. Herein, a novel and biocompatible scaffold was fabricated to locally deliver a precursor of NAD+, nicotinamide mononucleotide (NMN) to the bone defect site, and its bone repair capability and healing mechanism were clarified. NMN-based hyaluronic acid methacryloyl hybrid hydrogel scaffold (denoted as NMN/HAMA) was prepared via photopolymerization. In vitro RT-qPCR analysis, western blotting, Elisa and alizarin red S staining assays demonstrated that the NMN/HAMA hybrid hydrogel regulated BMSCs cellular function in favour of osteogenic differentiation and mineralization by upregulating the mRNA and proteins expression of the osteogenic genes type I pro-collagen (Col-1), bone morphogenic protein 4 (BMP4), and runt-related transcription factor 2 (RUNX2) via the SIRT1 pathway. Implantation of such hybrid hydrogels significantly enhanced bone regeneration in rodent critical calvarial defect models. Furthermore, restoration of the bone defect with NMN administration was inhibited in Prx1 Cre+; SIRT1flox/flox mice, confirming that the NMN/HAMA hybrid hydrogel scaffold promoted bone regeneration via the SIRT1-RUNX2 pathway. These results imply that NMN-based scaffold may be a promising and economic strategy for the treatment of bone defects.

Oroxylin A ameliorates ultraviolet radiation-induced premature skin aging by regulating oxidative stress via the Sirt1 pathway

Skin is susceptible to premature aging in response to ultraviolet (UV) radiation-induced oxidative stress, which can ultimately result in aberrant aging or age-related disorders. Accordingly, strategies that can be adopted to mitigate oxidative stress may contribute to protecting skin from induced aging-related damage, thereby offering promising approaches for the treatment of skin diseases and disorders. In this regard, oroxylin A (OA), a natural flavonoid isolated from certain plants used in traditional Chinese medicine, is considered to have notable antioxidant, anti-inflammatory, and anti-apoptotic properties, and is often used to treat certain inflammatory diseases. To date, however, there has been comparatively little research on the effects of OA with respect skin aging. In this study, we utilized UV radiation-induced mouse and cellular models of aging to assess the efficacy of OA in protecting against skin aging. Subsequently, to elucidate the potential mechanisms underlying the protective effect of OA on skin aging, we performed molecular docking analysis to investigate the involvement of the anti-aging gene Sirt1, which was further confirmed on the basis of Sirt1 gene silencing. We accordingly demonstrated that by promoting an increase in the expression of Sirt1, OA can contribute to suppressing UV-induced skin photo-aging in cells/mice by reducing oxidative stress. Furthermore, we established that by activating Sirt1, OA can also promote the dissociation of Nrf2 from Keap1 and its subsequent nuclear translocation. Collectively, our findings in this study reveal OA to be an effective natural compound that can be administered to delay the aging of skin triggered by UV, both in vivo and in vitro, by binding to Sirt1 to promote the deacetylation and nuclear translocation of Nrf2, thereby contributing to a reduction in oxidative stress. These findings may this provide a therapeutic target for the prevention of skin aging or aging-induced skin diseases.

Semaglutide alleviates early brain injury following subarachnoid hemorrhage by suppressing ferroptosis and neuroinflammation via SIRT1 pathway.

Subarachnoid hemorrhage (SAH) is a major cause of incapacity and death, imposing a significant economic burden globally. Additionally, SAH is the third most prevalent form of stroke. Semaglutide affects oxidative stress, inflammation, and mitochondrial biogenesis. Specifically, the potential neuroprotective effect of semaglutide in SAH and its underlying mechanism is unclear. Accordingly, the present research intended to explore the neuroprotective effect of semaglutide in SAH and its potential molecular mechanisms. We constructed a C57BL/6 mouse model of SAH. The parameters assessed were neuronal ferroptosis, neuroinflammatory cytokine levels, reactive oxygen species (ROS) levels, glutathione (GSH) and malondialdehyde (MDA) levels, brain water content, and neurological score. The results showed that the activation of semaglutide significantly increased neurological scores, relieved cerebral edema, decreased the levels of inflammatory cytokine nuclear factor kappa B, interleukin (IL)-1β, IL-6, tumor necrosis factor-alpha, MDA, and ROS, and increased the levels of GSH. Suppression of SIRT1 reversed these effects, indicating that semaglutide activated SIRT1 to reduce neuroinflammation, ferroptosis, and neuronal cell death after SAH. Thus, the activation of the Nrf2/HO-1 signaling pathway contributes to the neuroprotective properties of semaglutide. Semaglutide can improve murine neurological outcomes and reduce neuronal damage against neuroinflammation and ferroptosis.

Modulating SIRT1, Nrf2, and NF-κB signaling pathways by bergenin ameliorates the cadmium-induced nephrotoxicity in rats

In light of the current industrial evolution, exposure to cadmium has become a significant public health concern. Cadmium accumulates in the renal tubular cells and causes nephrotoxicity largely through disruption of the redox homeostasis, induction of inflammation, and suppression of the histone deacetylase SIRT1 expression. The current work aimed at exploring the protective capability of bergenin, a naturally-occurring methyl gallic acid derivative, against the cadmium-evoked nephrotoxicity. Male Wistar rats were treated either with cadmium alone or with cadmium and bergenin for a 7-day experimental period followed by collection of kidney and blood specimens that were subjected to biochemical, molecular, and histological investigations. The results revealed the ability of bergenin to improve the renal functions in the cadmium-intoxicated rats as evidenced by increased glomerular filtration rate, and decreased serum creatinine and blood urea nitrogen. Equally important, bergenin reduced the renal tissue injury and enhanced its redox homeostasis as indicated by decreased protein expression of the kidney injury marker KIM-1, reduced lipid peroxidation, and improved antioxidant potential and histopathological picture of the renal tissues. Mechanistically, bergenin reduced the renal tissue cadmium content, markedly up-regulated protein expression of SIRT1 that regulates inflammation and the redox status of the renal tissues. Additionally, it improved the expression of the major antioxidant transcription factor Nrf2 and its responsive gene products heoxygenase-1 and NAD(P)H quinone dehydrogenase 1 in the cadmium-intoxicated rats. In the same context, bergenin down-regulated the acetylation and the nuclear translocation of the inflammatory transcription factor NF-κB and reduced levels of its responsive gene products TNF-α and IL-1β, as well as the activity of the inflammatory cell infiltration biomarker myeloperoxidase. Collectively, the current study underscores the ameliorating activity of bergenin against the cadmium-evoked nephrotoxicity and highlights modulation of SIRT1, Nrf2, and NF-κB signaling as potential underlining molecular mechanisms.

Pterostilbene exerts cytotoxicity on activated hepatic stellate cells by inhibiting excessive proliferation through the crosstalk of Sirt1 and STAT3 pathways.

Pterostilbene (PTE), a natural analogue of resveratrol, abundantly exists in blueberries and grapes and has several beneficial potentials against oxidative stress, inflammation, and cancer. In current study, we investigated the effects of PTE on hepatic fibrosis in vitro and in vivo. Activation of hepatic stellate cells (HSCs) is an initiating event in the initiation of hepatic fibrosis. MTT assay revealed that PTE (3.125-12.5 μM) displayed cytotoxicity on activated HSCs, no cytotoxicity on AML-12 and quiescent HSCs. PTE significantly inhibited the expressions of α-SMA, collagen Ⅰ and TIMP-1/MMP13 ratio; suppressed inflammatory cascade activation to reduce inflammatory cytokines release, such as Caspase-1, IL-1β and IL-6. PTE activated Sirt1 and decreased STAT3 phosphorylation, functioning as SRT1720 and Niclosamide. Sirt1 deficiency significantly elevated p-STAT3 expression, while STAT3 deficiency resulted in Sirt1 increasing and inhibited fibrosis and inflammatory cytokines expressions. In mice with hepatic fibrosis induced by thioacetamide (TAA), PTE significantly decreased ALT and AST activities, reduced fibrosis markers, STAT3 phosphorylation and activated Sirt1 expression. PTE showed cytotoxicity on activated HSCs to ameliorate hepatic fibrosis via regulating fibrogenesis, energy metabolism and inflammation and targeting the crosstalk of Sirt1 and STAT3. In conclusion, PTE could be potentially beneficial as a natural plant metabolite in preventing and treating hepatic fibrosis.

Lipoic acid inhibits cognitive impairment induced by multiple cell phones in young male rats: role of Sirt1 and Atg7 pathway

The utilization of digital technology has grown rapidly in the past three decades. With this rapid increase, cell phones emit electromagnetic radiation; that is why electromagnetic field (EMF) has become a substantial new pollution source in modern civilization, mainly having adverse effects on the brain. While such a topic attracted many researchers’ scopes, there are still minimal discoveries made regarding chronic exposure to EMF. The extensive use of cell phones may affect children's cognition even indirectly if parents and guardians used their phones repeatedly near them. This study aims to investigate possible lipoic acid (LA) effects on cognitive functions and hippocampal structure in young male rats exposed to electromagnetic fields (EMF) emitted from multiple cell phones. Forty young male Wistar rats were randomly allocated into three groups: control, multiple cell phones-exposed and lipoic acid-treated rats. By the end of the experimental period, the Morris water maze was used as a cognitive test. The rats were sacrificed for the collection of serum and hippocampal tissue. These serum samples were then utilized for assessment of Liver function tests. The level ofglutamate, acetylcholine (Ach) and malondialdehyde (MDA) was estimated, in addition to evaluating the expression of autophagy-related protein-7 (Atg7) and Sirt1 genes. The left hippocampal specimens were used for histopathological studies. Results showed that multiple cell phone-exposed rats exhibited shorter latency time to reach the platform by the fifth day of training; additionally, there was a reduction in consolidation of spatial long-term memory. Correspondingly, there was an elevation of hippocampal Ach, glutamate, and MDA levels; accompanied by up-regulation of hippocampal Sirt1 and Atg7 gene expression. Compared to the EMF-exposed group, LA administration improved both learning and memory, this was proved by the significant decline in hippocampal MDA and Ach levels, the higher hippocampal glutamate, the downregulated hippocampal Sirt1 gene expression and the upregulated Atg7 gene expression. In conclusion, EMF exposure could enhance learning ability; however, it interfered with long-term memory consolidation shown by higher hippocampal Ach levels. Lipoic acid treatment improved both learning and memory by enhancing autophagy and hippocampal glutamate level and by the reduced Ach levels and Sirt1 gene expression.

Canagliflozin ameliorates ulcerative colitis via regulation of TLR4/MAPK/NF-κB and Nrf2/PPAR-γ/SIRT1 signaling pathways

Ulcerative colitis (UC) is one of the most common subtypes of inflammatory bowel disease (IBD) that affects the colon and is characterized by severe intestinal inflammation. Canagliflozin is a widely used antihyperglycemic agent, a sodium-glucose cotransporter-2 (SGLT2) inhibitor that enhances urinary glucose excretion. This study aims to provide insights into the potential benefits of canagliflozin as a treatment for UC by addressing possible cellular signals. Acetic acid (AA; 4% v/v) was administered intrarectally to induce colitis. Canagliflozin is given orally at a dose of 10 mg/kg/day. Canagliflozin attenuates inflammation in AA-induced colitis, evidenced by significant and dose-dependently downregulation of p38 MAPK, NF-κB-p65, IKK, IRF3, and NADPH-oxidase as well as colonic levels of IL-6 and IL-1β and MPO enzymatic activity. Canagliflozin mitigates colonic oxidative stress by decreasing MDA content and restoring SOD enzymatic activities and GSH levels mediated by co-activating of Nrf2, PPARγ, and SIRT1 pathways. Moreover, an in-silico study confirmed that canagliflozin was specific to all target proteins in this study. Canagliflozin's binding affinity with its target proteins indicates and confirms its effectiveness in regulating these pathways. Also, network pharmacology analysis supported that canagliflozin potently attenuates UC via a multi-target and multi-pathway approach.

Melatonin Modulates the SIRT1-Related Pathways via Transdermal Cryopass-Laser Administration in Prostate Tumor Xenograft.

Melatonin displays antitumor activity in several types of malignancies; however, the best delivery route and the underlying mechanisms are still unclear. Alternative non-invasive delivery route based on transdermal administration of melatonin by cryopass-laser treatment demonstrated efficiency in reducing the progression of LNCaP prostate tumor cells xenografted into nude mice by impairing the biochemical pathways affecting redox balance. Here, we investigated the impact of transdermal melatonin on the tumor dimension, microenvironment structure, and SIRT1-modulated pathways. Two groups (vehicle cryopass-laser and melatonin cryopass-laser) were treated for 6 weeks (3 treatments per week), and the tumors collected were analyzed for hematoxylin eosin staining, sirius red, and SIRT1 modulated proteins such as PGC-1α, PPARγ, and NFkB. Melatonin in addition to simple laser treatment was able to boost the antitumor cancer activity impairing the tumor microenvironment, increasing the collagen structure around the tumor, and modulating the altered SIRT1 pathways. Transdermal application is effective, safe, and feasible in humans as well, and the significance of these findings necessitates further studies on the antitumor mechanisms exerted by melatonin.

NADH elevation during chronic hypoxia leads to VHL-mediated HIF-1α degradation via SIRT1 inhibition

BackgroundUnder conditions of hypoxia, cancer cells with hypoxia inducible factor-1α (HIF-1α) from heterogeneous tumor cells show greater aggression and progression in an effort to compensate for harsh environmental conditions. Extensive study on the stability of HIF-1α under conditions of acute hypoxia in cancer progression has been conducted, however, understanding of its involvement during the chronic phase is limited.MethodsIn this study, we investigated the effect of SIRT1 on HIF1 stability in a typical chronic hypoxic conditon that maintains cells for 24 h under hypoxia using Western blotting, co-IP, measurement of intracellular NAD + and NADH levels, semi-quantitative RT-PCR analysis, invasion assay, gene knockdown.ResultsHere we demonstrated that the high concentration of pyruvate in the medium, which can be easily overlooked, has an effect on the stability of HIF-1α. We also demonstrated that NADH functions as a signal for conveyance of HIF-1α degradation via the SIRT1 and VHL signaling pathway under conditions of chronic hypoxia, which in turn leads to attenuation of hypoxically strengthened invasion and angiogenic activities. A steep increase in the level of NADH occurs during chronic hypoxia, leading to upregulation of acetylation and degradation of HIF-1α via inactivation of SIRT1. Of particular interest, p300-mediated acetylation at lysine 709 of HIF-1α is recogonized by VHL, which leads to degradation of HIF-1α via ubiquitin/proteasome machinary under conditions of chronic hypoxia. In addition, we demonstrated that NADH-elevation-induced acetylation and subsequent degradation of HIF-1α was independent of proline hydroxylation.ConclusionsOur findings suggest a critical role of SIRT1 as a metabolic sensor in coordination of hypoxic status via regulation of HIF-1α stability. These results also demonstrate the involvement of VHL in degradation of HIF-1α through recognition of PHD-mediated hydroxylation in normoxia and p300-mediated HIF-1α acetylation in hypoxia.

Cellular metabolic pathways of aging in dogs: could p53 and SIRT1 be at play?

Aging and cancer seem to be closely associated, such that cancer is generally considered a disease of the elderly in both humans and dogs. Additionally, cancer is a metabolic shift in itself towards aerobic glycolysis. Larger dog breeds with shorter lifespans, and increased glycolytic cellular metabolic rates, die of cancer more often than smaller breeds. The tumor suppressor p53 factor is a key suppressor oncogene, and the p53 pathway arrests cellular proliferation and prevents DNA mutations from accumulating during cellular stress. The p53 pathway is also associated with the control of cellular metabolism to prevent cellular metabolic shifts common to cancerous phenotypes. SIRT1 deacetylates the p53 tumor suppressor protein, downregulating p53 via effects on stability and activity during stress. Here, we used primary fibroblast cells from small and large puppies and old dogs. Using UV radiation to upregulate the p53 system (100J/m2), control cells and UV-treated cells were used to measure aerobic and glycolytic metabolic rates using a Seahorse XFe96 oxygen flux analyzer. We also quantified p53 expression and SIRT1 concentration in canine primary fibroblasts before and after UV treatment. We demonstrate that, due to a higher p53 nuclear to cytoplasmic ratio in large breed dogs after UV treatment, p53 could have a more regulatory effect on large breed dogs' metabolism compared with smaller breeds. Thus, there may be a link between p53 upregulation and inhibition of glycolysis in large breed dogs during times of cellular stress compared with small breed dogs. However, SIRT1 concentrations decrease with age in domestic dogs of both size classes, suggesting a possible release of inhibition of p53 through the SIRT1 pathway with age. This may lead to increased incidences of cancer, especially due to the more pronounced upregulation of p53 with cellular stress.

Nuciferine induces autophagy to relieve vascular cell adhesion molecule 1 activation via repressing the Akt/mTOR/AP1 signal pathway in the vascular endothelium.

Pro-inflammatory factor-associated vascular cell adhesion molecule 1 (VCAM1) activation initiates cardiovascular events. This study aimed to explore the protective role of nuciferine on TNFα-induced VCAM1 activation. Nuciferine was administrated to both high-fat diet (HFD)-fed mice and the TNFα-exposed human vascular endothelial cell line. VCAM1 expression and further potential mechanism(s) were explored. Our data revealed that nuciferine intervention alleviated VCAM1 activation in response to both high-fat diet and TNFα exposure, and this protective effect was closely associated with autophagy activation since inhibiting autophagy by either genetic or pharmaceutical approaches blocked the beneficial role of nuciferine. Mechanistical studies revealed that Akt/mTOR inhibition, rather than AMPK, SIRT1, and p38 signal pathways, contributed to nuciferine-activated autophagy, which further ameliorated TNFα-induced VCAM1 via repressing AP1 activation, independent of transcriptional regulation by IRF1, p65, SP1, and GATA6. Collectively, our data uncovered a novel biological function for nuciferine in protecting VCAM1 activation, implying its potential application in improving cardiovascular events.

Rebalancing of mitochondrial homeostasis through an NAD+-SIRT1 pathway preserves intestinal barrier function in severe malnutrition

The intestine of children with severe malnutrition (SM) shows structural and functional changes that are linked to increased infection and mortality. SM dysregulates the tryptophan-kynurenine pathway, which may impact processes such as SIRT1- and mTORC1-mediated autophagy and mitochondrial homeostasis. Using a mouse and organoid model of SM, we studied the repercussions of these dysregulations on malnutrition enteropathy and the protective capacity of maintaining autophagy activity and mitochondrial health. SM was induced through feeding male weanling C57BL/6 mice a low protein diet (LPD) for 14-days. Mice were either treated with the NAD+-precursor, nicotinamide; an mTORC1-inhibitor, rapamycin; a SIRT1-activator, resveratrol; or SIRT1-inhibitor, EX-527. Malnutrition enteropathy was induced in enteric organoids through amino-acid deprivation. Features of and pathways to malnutrition enteropathy were examined, including paracellular permeability, nutrient absorption, and autophagic, mitochondrial, and reactive-oxygen-species (ROS) abnormalities. LPD-feeding and ensuing low-tryptophan availability led to villus atrophy, nutrient malabsorption, and intestinal barrier dysfunction. In LPD-fed mice, nicotinamide-supplementation was linked to SIRT1-mediated activation of mitophagy, which reduced damaged mitochondria, and improved intestinal barrier function. Inhibition of mTORC1 reduced intestinal barrier dysfunction and nutrient malabsorption. Findings were validated and extended using an organoid model, demonstrating that resolution of mitochondrial ROS resolved barrier dysfunction. Malnutrition enteropathy arises from a dysregulation of the SIRT1 and mTORC1 pathways, leading to disrupted autophagy, mitochondrial homeostasis, and ROS. Whether nicotinamide-supplementation in children with SM could ameliorate malnutrition enteropathy should be explored in clinical trials. This work was supported by the Bill and Melinda Gates Foundation, the Sickkids Research Institute, the Canadian Institutes of Health Research, and the University Medical Center Groningen.

The long non-coding RNA maternally expressed 3-micorRNA-15a-5p axis is modulated by melatonin and prevents nucleus pulposus cell inflammation and apoptosis.

Nucleus pulposus (NP) cell apoptosis is regarded as a critical risk factor for intervertebral disc degeneration (IVDD). Melatonin exerts a protective role on NP cells. The study concentrates on the role and mechanism of lncRNA MEG3 in melatonin-mediated effects on NP cells. An in vitro IVDD model was constructed using IL-1β on human NP cells. qRT-PCR investigated MEG3, miR-15a-5p and PGC-1α mRNA levels in tissues and NP cells. IL-1β-treated NP cells subsequent to transfection, followed by melatonin treatment. NP cell proliferation, viability, apoptosis and inflammatory reactions were assayed. Western blot checked the profiles of PGC-1α, SIRT1 and NF-κB p65. Student's t-test or one-way analysis of variance (ANOVA) followed by Tukey's test was used for statistical tests. As indicated by the data, melatonin weakened NP cell inflammation and apoptosis and enhanced MEG3 expression. MEG3 expression was attenuated in IVDD tissues. MEG3 knockdown impaired the function of melatonin, which was, however, strengthened by miR-15a-5p knockdown. MEG3 targeted miR-15a-5p, which targeted PGC-1α and repressed the PGC-1α/SIRT1 pathway. Collectively, this study has disclosed that the MEG3-miR-15a-5p-PGC-1α/SIRT1 pathway modulated by melatonin can hamper NP cell apoptosis and inflammation elicited by IL-1β.

HDAC3-mediated lncRNA ZFAS1 inhibited IL-13-induced secretion of proinflammatory cytokines in nasal epithelial cells by regulating the miR-7-5p/SIRT1 pathway.

Allergic rhinitis (AR) is a disease that is difficult to cure and accompanies the patient's life. Proinflammatory cytokines (GM-CSF and eotaxin) and MUC5AC are key mediators promoting AR progression. Herein, the function of lncRNA ZFAS1 in AR was investigated. Nasal epithelial cells (NECs) were subjected to 50ng/mL IL-13 for 24h to construct an AR cell model. The mRNA and protein expressions were assessed using qRT-PCR and western blot. The levels of GM-CSF, eotaxin, IL-1β, IL-6, TNF-α and MUC5AC in cell supernatant were examined by ELISA. The binding relationships between HDAC3, ZFAS1, miR-7-5p and SIRT1 were analysed using dual luciferase reporter or ChIP assays. Herein, our results displayed that ZFAS1 and SIRT1 were lowly expressed in AR, while miR-7-5p and HDAC3 were highly expressed. Functional experiments displayed that ZFAS1 overexpression suppressed IL-13-induced proinflammatory cytokines and mucin production in NECs. The highly expressed HDAC3 in AR inhibited ZFAS1 expression by binding with ZFAS1 promoter. In addition, our experiments revealed that ZFAS1 targeted miR-7-5p, and miR-7-5p targeted SIRT1. As expected, miR-7-5p overexpression or SIRT1 silencing abrogated ZFAS1 upregulation's repression on IL-13-induced proinflammatory cytokines and MUC5AC secretory levels in NECs. ZFAS1 suppressed proinflammatory cytokines, inflammatory cytokines, and MUC5AC secretory levels in AR by regulating the miR-7-5p/SIRT1 axis. Thus, our work suggested that ZFAS1 might serve as a novel target for AR treatment and prevention.

Matcha-silver nanoparticles reduce gamma radiation-induced oxidative and inflammatory responses by activating SIRT1 and NLRP-3 signaling pathways in the Wistar rat spleen.

The biogenic synthesis of nanoparticles has drawn significant attention. The spleen is the largest lymphatic organ that is adversely impacted during irradiation. The current study was designated to evaluate the possible anti-inflammatory effect of matcha-silver nanoparticles (M-AgNPs) to reduce inflammation associated with γ-radiation induced-oxidative stress and inflammation in rats' spleen. Silver nanoparticles (AgNPs) were synthesized by biogenic synthesis using a green sonochemical method from matcha (M) green tea. The obtained M-AgNPs were extensively characterized by dynamic light scattering, transmission electron microscopy, thermogravimetric analysis, and Fourier-transform infrared spectroscopy. Using zetasizer analysis, the surface charge, particle size, and radical scavenging DPPH assay of M-AgNPs were also examined. Biocompatibility and cytotoxicity were analyzed by MTT assay, and the IC50 was calculated. Four groups of 24 Wistar rats each had an equal number of animals. The next step involved measuring the levels of oxidative stress markers in the rat splenic tissue. Additionally, the amounts of inflammatory protein expression were evaluated using the ELISA analysis. The results indicated the formation of spherical nanoparticles of pure Ag° coated with matcha polyphenols at the nanoscale, as well as uniform monodisperse particles suited for cellular absorption. Results revealed that M-AgNPs improved all biochemical parameters. Furthermore, M-AgNPs relieve inflammation by reducing the expression of NOD-like receptor family pyrin domain-containing 3 (NLRP3), interleukin-1β (IL-1β), and enhancing the levels of ileSnt information regulator 1 (SIRT1). Histopathological examinations demonstrated the ability of M-AgNPs to overcome the damage consequent to irradiation and recover the spleen's cellular structure. These results confirmed that matcha is a potential biomaterial for synthesizing AgNPs, which can be exploited for their anti-inflammatory activity.

Electroacupuncture intervention improves lipid metabolism and promotes browning of white adipose tissue by activating AMPK/Sirt1 pathway and up-regulating Nrg4 content in middle-aged and aged obese rats

To investigate the mechanism of electroacupuncture （EA） in promoting the browning of white adipose tissue in middle-aged and aged obese rats induced by high fat by regulating AMP-activated protein kinase （AMPK） /silence-information regulatory factor 1 （Sirt1） pathway and neuregulin 4 （Nrg4）. Twenty-four male SD rats were randomized into blank control, model and EA groups （n=8 per group）. The obesity model was established by feeding the rats with high-fat diet for 6 weeks. For the EA group, EA （2 Hz/15 Hz, 1.5 mA） was applied to "Guanyuan" （CV4） and bilateral "Shenshu" （BL23）, "Fenglong" （ST40） and "Tianshu" （ST25） for 20 min, once a day, 5 days a week for 6 weeks. Rats of the blank control and model groups were also restrained for 20 min. The body mass and food intake were measured every week, and the Lee's index, epididymal fat, perirenal fat and brown adipose tissue were weighed. The contents of serum total cholesterol （TC）, triglyceride （TG）, high density lipoprotein cholesterol （HDL-C）, low density lipoprotein cholesterol （LDL-C） and norepinephrine （NE） were determined by ELISA. H.E. staining was used to observe the morphological changes of white and brown adipose tissue. The mRNA expression levels of mitochondrial uncoupling protein 1 （UCP1）, peroxisome proliferator activated receptor γ co-activator 1α （PGC-1α）, PR-domain protein 16 （PRDM16）, peroxisome proliferator activated receptor γ （PPARγ） and Nrg4 in the adipose tissue were detected by quantitative real time PCR, and the protein expression levels of Nrg4, AMPKα, Sirt1 and interleukin-6 （IL-6） in the white and brown adipose tissue were detected by Western blot. Compared with the blank control group, the body mass, food intake, the Lee's index, epididymal fat and perirenal fat mass, and serum TG, TC and LDL-C contents and the expression level of IL-6 protein were significantly increased （P<0.01, P<0.05, P<0.001）, and the brown adipose mass, serum HDL-C and NE contents, the expression levels of UCP1, PGC-1α, PRDM16, PPARγ and Nrg4 mRNAs, and the protein expression levels of AMPKα, Sirt1 and Nrg4 proteins in both white and brown adipose tissues were significantly decreased in the model group （P<0.01, P<0.05）. After EA intervention, the increased levels of body mass, food intake, Lee's index, epididymal fat and perirenal fat mass, serum TG, TC and LDL-C contents, and the expression of IL-6 protein, and the decreased levels of brown adipose mass, serum HDL-C and NE contents, expression levels of UCP1, PGC-1α, PRDM16, PPARγ and Nrg4 mRNAs, and those of AMPKα, Sirt1 and Nrg4 proteins in both white and brown adipose tissues were apparently reversed（P<0.05, P<0.01, P<0.001）. H.E. staining showed an increase of the volume and content of intracellular vacuoles of both white and brown adipose tissues, disordered arrangement of cells with vague boundary in the model group, which was relatively milder including a decrease of volume and content of vacuoles of both white and brown adipose, neat arrangement of cells with clear boundary. EA intervention can improve lipid metabolism and promote white adipose tissue browning in middle-aged and aged obese rats, which is possibly associated with its functions in activating AMPK/Sirt1 signaling pathway and up-regulating the level of Nrg4.

Electroacupuncture intervention improves lipid metabolism and promotes browning of white adipose tissue by activating AMPK/Sirt1 pathway and up-regulating Nrg4 content in middle-aged and aged obese rats

To investigate the mechanism of electroacupuncture （EA） in promoting the browning of white adipose tissue in middle-aged and aged obese rats induced by high fat by regulating AMP-activated protein kinase （AMPK） /silence-information regulatory factor 1 （Sirt1） pathway and neuregulin 4 （Nrg4）. Twenty-four male SD rats were randomized into blank control, model and EA groups （n=8 per group）. The obesity model was established by feeding the rats with high-fat diet for 6 weeks. For the EA group, EA （2 Hz/15 Hz, 1.5 mA） was applied to "Guanyuan" （CV4） and bilateral "Shenshu" （BL23）, "Fenglong" （ST40） and "Tianshu" （ST25） for 20 min, once a day, 5 days a week for 6 weeks. Rats of the blank control and model groups were also restrained for 20 min. The body mass and food intake were measured every week, and the Lee's index, epididymal fat, perirenal fat and brown adipose tissue were weighed. The contents of serum total cholesterol （TC）, triglyceride （TG）, high density lipoprotein cholesterol （HDL-C）, low density lipoprotein cholesterol （LDL-C） and norepinephrine （NE） were determined by ELISA. H.E. staining was used to observe the morphological changes of white and brown adipose tissue. The mRNA expression levels of mitochondrial uncoupling protein 1 （UCP1）, peroxisome proliferator activated receptor γ co-activator 1α （PGC-1α）, PR-domain protein 16 （PRDM16）, peroxisome proliferator activated receptor γ （PPARγ） and Nrg4 in the adipose tissue were detected by quantitative real time PCR, and the protein expression levels of Nrg4, AMPKα, Sirt1 and interleukin-6 （IL-6） in the white and brown adipose tissue were detected by Western blot. Compared with the blank control group, the body mass, food intake, the Lee's index, epididymal fat and perirenal fat mass, and serum TG, TC and LDL-C contents and the expression level of IL-6 protein were significantly increased （P<0.01, P<0.05, P<0.001）, and the brown adipose mass, serum HDL-C and NE contents, the expression levels of UCP1, PGC-1α, PRDM16, PPARγ and Nrg4 mRNAs, and the protein expression levels of AMPKα, Sirt1 and Nrg4 proteins in both white and brown adipose tissues were significantly decreased in the model group （P<0.01, P<0.05）. After EA intervention, the increased levels of body mass, food intake, Lee's index, epididymal fat and perirenal fat mass, serum TG, TC and LDL-C contents, and the expression of IL-6 protein, and the decreased levels of brown adipose mass, serum HDL-C and NE contents, expression levels of UCP1, PGC-1α, PRDM16, PPARγ and Nrg4 mRNAs, and those of AMPKα, Sirt1 and Nrg4 proteins in both white and brown adipose tissues were apparently reversed（P<0.05, P<0.01, P<0.001）. H.E. staining showed an increase of the volume and content of intracellular vacuoles of both white and brown adipose tissues, disordered arrangement of cells with vague boundary in the model group, which was relatively milder including a decrease of volume and content of vacuoles of both white and brown adipose, neat arrangement of cells with clear boundary. EA intervention can improve lipid metabolism and promote white adipose tissue browning in middle-aged and aged obese rats, which is possibly associated with its functions in activating AMPK/Sirt1 signaling pathway and up-regulating the level of Nrg4.

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

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

GLP-1RA Liraglutide and Semaglutide Improves Obesity-Induced Muscle Atrophy via SIRT1 Pathway.

Obesity is related to the loss of skeletal muscle mass and function (sarcopenia). The co-existence of obesity and sarcopenia is called sarcopenic obesity (SO). Glucagon like peptide-1 receptor agonists (GLP-1RA) are widely used in the treatment of diabetes and obesity. However, the protective effects of GLP-1RA on skeletal muscle in obesity and SO are not clear. This study investigated the effects of GLP-1RA liraglutide and semaglutide on obesity-induced muscle atrophy and explored the underlying mechanisms. Thirty-six male C57BL/6J mice were randomly divided into two groups and fed a regular diet and a high-fat diet for 18 weeks, respectively. After establishing an obesity model, mice were further divided into six groups: control group, liraglutide (LIRA) group, semaglutide (SEMA) group, high-fat diet (HFD) group, HFD + LIRA group, HFD + SEMA group, and subcutaneous injection for 4 weeks. The body weight, muscle mass, muscle strength, glycolipid metabolism, muscle atrophy markers, myogenic differentiation markers, GLUT4 and SIRT1 were analyzed. C2C12 myotube cells treated with palmitic acid (PA) were divided into four groups: control group, PA group, PA + LIRA group, PA + SEMA group. The changes in glucose uptake, myotube diameter, lipid droplet infiltration, markers of muscle atrophy, myogenic differentiation markers, GLUT4 and SIRT1 were analyzed, and the changes in related indicators were observed after the addition of SIRT1 inhibitor EX527. Liraglutide and semaglutide reduced HFD-induced body weight gain, excessive lipid accumulation and improved muscle atrophy. Liraglutide and semaglutide eliminated the increase of muscle atrophy markers in skeletal muscle and C2C12 myotubes. Liraglutide and semaglutide restored impaired glucose tolerance and insulin resistance. However, these beneficial effects were attenuated by inhibiting SIRT1 expression. Liraglutide and semaglutide protects skeletal muscle against obesity-induced muscle atrophy via the SIRT1 pathway.