Water-soluble 4-(dimethylaminomethyl)heliomycin exerts greater antitumor effects than parental heliomycin by targeting the tNOX-SIRT1 axis and apoptosis in oral cancer cells.

The antibiotic heliomycin (resistomycin), which is generated from Streptomyces resistomycificus, has multiple activities, including anticancer effects. Heliomycin was first described in the 1960s, but its clinical applications have been hindered by extremely low solubility. A series of 4-aminomethyl derivatives of heliomycin were synthesized to increase water solubility; studies showed that they had anti-proliferative effects, but the drug targets remained unknown. In this study, we conducted cellular thermal shift assays (CETSA) and molecular docking simulations to identify and validate that heliomycin and its water-soluble derivative, 4-(dimethylaminomethyl)heliomycin (designated compound 4-dmH) engaged and targeted with sirtuin-1 (SIRT1) in p53-functional SAS and p53-mutated HSC-3 oral cancer cells. We further addressed the cellular outcome of SIRT1 inhibition by these compounds and found that, in addition to SIRT1, the water-soluble 4-dmH preferentially targeted a tumor-associated NADH oxidase (tNOX, ENOX2). The direct binding of 4-dmH to tNOX decreased the oxidation of NADH to NAD+ which diminished NAD+-dependent SIRT1 deacetylase activity, ultimately inducing apoptosis and significant cytotoxicity in both cell types, as opposed to the parental heliomycin-induced autophagy. We also observed that tNOX and SIRT1 were both upregulated in tumor tissues of oral cancer patients compared to adjacent normal tissues, suggesting their clinical relevance. Finally, the better therapeutic efficacy of 4-dmH was confirmed in tumor-bearing mice, which showed greater tNOX and SIRT1 downregulation and tumor volume reduction when treated with 4-dmH compared to heliomycin. Taken together, our in vitro and in vivo findings suggest that the multifaceted properties of water-soluble 4-dmH enable it to offer superior antitumor value compared to parental heliomycin, and indicated that it functions through targeting the tNOX-NAD+-SIRT1 axis to induce apoptosis in oral cancer cells.

Icariin alleviates the apoptosis of chondrocytes in osteoarthritis through regulating SIRT-1-Nrf2-HO-1 signaling.

Icariin has shown the potential to treat osteoarthritis (OA), but the specific mechanism still needs further exploration. Therefore, this study attempted to reveal the effect and mechanism of icariin on OA based on in vitro and in vivo experiments. In vivo, a mouse model of OA was established by cutting the anterior cruciate ligament, and 10 mg/kg icariin was given to mice orally. Then, the OA injury and pathological changes of cartilage tissue in mice were identified by OA index and hematoxylin and eosin staining. In vitro, the viability of C28/I2 cells incubated with different concentrations of icariin was detected by 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di- phenytetrazoliumromide assay. Subsequently, C28/I2 cells induced by IL-1ß were used as the cell model of OA, the expression of Sirtuin (SIRT)-1 in cells was knocked down, and icariin was added for intervention. Next, western blot was used to observe the expression level of sirtuin 1 (SIRT-1)-Nrf2-heme oxygenase 1 (HO-1) signaling pathway-related proteins in cells of each group. Besides, cell viability and apoptosis were detected by MTT and apoptosis assay, and DNA damage was observed by comet assay. In vivo experiments, intragastric administration of icariin could effectively reduce the OA index of mice, improve the pathological changes of cartilage tissue, and obviously activated the SIRT-1-Nrf2-HO-1 signaling pathway. In vitro experiments, icariin did not exhibit toxic effect on C28/I2 cells, but could activate the SIRT-1-Nrf2-HO-1 signaling pathway, improve the viability, reduce the level of apoptosis and relieve the DNA damage in OA cells; however, these effects were inhibited by si- SIRT-1. Icariin can improve the symptoms of OA by activating the SIRT-1-Nrf2-HO-1 signaling pathway.

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

BACKGROUND: DNA 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. METHODS: A 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. RESULTS: The 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. CONCLUSIONS: Our 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.

Nephroprotective effect of Ginsenoside Rg1 in lipopolysaccharide-induced sepsis in mice through the SIRT1/NF-κB signaling.

INTRODUCTION: During sepsis, the kidney is one of the most vulnerable organs. Sepsis-associated acute kidney injury (S-AKI) is hallmarked by renal inflammation, apoptosis, and oxidative injury. Ginsenoside Rg1 (Rg1) is a natural product that possesses abundant pharmacological actions and protects against many sepsis-related diseases. Nevertheless, its role and related mechanism in S-AKI remain to be determined. MATERIALS AND METHODS: S-AKI was induced using lipopolysaccharide (LPS, 10 mg/kg) via a single intraperitoneal injection. Rg1 (200 mg/kg) was intraperitoneally administered for 3 consecutive days before LPS treatment. For histopathological examination, murine kidney tissues were stained with hematoxylin and eosin. Tubular injury score was calculated to evaluate kidney injury. Serum creatinine and BUN levels were measured for assessing renal dysfunction. The levels and activities of oxidative stress markers (MDA, 4-HNE, PC, GSH, SOD, and CAT) in renal tissue were measured by corresponding kits. Renal cell apoptosis was detected by TUNEL staining. The protein levels of apoptosis-related markers (Bcl-2, Bax, and Cleaved caspase-3), proinflammatory factors, SIRT1, IκBα, p-NF-κB p65, and NF-κB p65 in kidneys were determined using western blotting. Immunofluorescence staining was employed to assess p-NF-κB p65 expression in renal tissues. RESULTS: LPS-induced injury of kidneys and renal dysfunction in mice were ameliorated by Rg1. Rg1 also impeded LPS-evoked renal cell apoptosis in kidneys. Moreover, Rg1 attenuated LPS-triggered inflammation and oxidative stress in kidneys by inhibiting proinflammatory cytokine release, enhancing antioxidant levels and activities, and reducing lipid peroxidation. However, all these protective effects of Rg1 in LPS-induced AKI mice were reversed by EX527, an inhibitor of sirtuin 1 (SIRT1). Mechanistically, Rg1 upregulated SIRT1 protein expression, increased SIRT1 activity, and inactivated NF-κB signaling in the kidney of LPS-induced AKI mice, which was also reversed by EX527. CONCLUSIONS: Rg1 ameliorates LPS-induced kidney injury and suppresses renal inflammation, apoptosis, and oxidative stress in mice via regulating the SIRT1/NF-κB signaling.

MiR-34a ameliorates arterial blood flow in rats with lower limb arteriosclerosis obliterans via Sirt1 signaling pathway.

In this study, we investigated the impact of microRNA-34a (miR-34a) on lower limb arteriosclerosis obliterans in rats through the Sirtuin 1 (Sirt1) signaling pathway. Thirty-six Sprague-Dawley rats were divided into normal, model, and miR-34a mimics groups. Rats in the normal group were raised normally, while the model group underwent lower limb arteriosclerosis obliterans induction and received saline injections. The miR-34a mimics group also underwent arteriosclerosis obliterans modeling but received miR-34a mimics injections. Immunohistochemistry revealed significantly increased vascular endothelial growth factor (VEGF) expression in both model and miR-34a mimics groups compared to the normal group, with the miR-34a mimics group showing higher levels. Western blotting indicated elevated Sirt1 protein expression in both non-normal groups, with the miR-34a mimics group exhibiting significantly higher levels. Quantitative polymerase chain reaction (qPCR) demonstrated higher levels of miR-34a, VEGF mRNA, and Sirt1 mRNA in the model group compared to the normal group, but significantly lower levels than the miR-34a mimics group. Enzyme-linked immunosorbent assay (ELISA) showed increased VEGF content in the model group compared to the normal group but decreased compared to the miR-34a mimics group. Hemorrheological detection revealed a reduced PU index in both non-normal groups compared to the normal group, with a significant increase in the miR-34a mimics group compared to the model group. Overall, miR-34a upregulation enhanced VEGF expression in rat blood vessels, ameliorating arterial blood flow in lower limb arteriosclerosis obliterans through the Sirt1 signaling pathway.

Nicotinamide Mononucleotide improves oocyte maturation of mice with type 1 diabetes.

BACKGROUND: The number of patients with type 1 diabetes rises rapidly around the world in recent years. Maternal diabetes has a detrimental effect on reproductive outcomes due to decreased oocyte quality. However, the strategies to improve the oocyte quality and artificial reproductive technology (ART) efficiency of infertile females suffering from diabetes have not been fully studied. In this study, we aimed to examine the effects of nicotinamide mononucleotide (NMN) on oocyte maturation of mouse with type 1 diabetes mouse and explore the underlying mechanisms of NMN's effect. METHODS: Streptozotocin (STZ) was used to establish the mouse models with type 1 diabetes. The successful establishment of the models was confirmed by the results of body weight test, fasting blood glucose test and haematoxylin and eosin (H&E) staining. The in vitro maturation (IVM) rate of oocytes from diabetic mice was examined. Immunofluorescence staining (IF) was performed to examine the reactive oxygen species (ROS) level, spindle/chromosome structure, mitochondrial function, actin dynamics, DNA damage and histone modification of oocytes, which are potential factors affecting the oocyte quality. The quantitative reverse transcription PCR (RT-qPCR) was used to detect the mRNA levels of Sod1, Opa1, Mfn2, Drp1, Sirt1 and Sirt3 in oocytes. RESULTS: The NMN supplementation increased the oocyte maturation rate of the mice with diabetes. Furthermore, NMN supplementation improved the oocyte quality by rescuing the actin dynamics, reversing meiotic defects, improving the mitochondrial function, reducing ROS level, suppressing DNA damage and restoring changes in histone modifications of oocytes collected from the mice with diabetes. CONCLUSION: NMN could improve the maturation rate and quality of oocytes in STZ-induced diabetic mice, which provides a significant clue for the treatment of infertility of the patients with diabetes.

Bifidobacterium pseudocatenulatum NCU-08 ameliorated senescence via modulation of the AMPK/Sirt1 signaling pathway and gut microbiota in mice.

Aging is a degenerative disease in which organisms and neurological functions decline. Emerging research has underscored the vital role of the gut microbiota in age-related processes. However, the identification of aging-associated core microbiota remains limited. In this investigation, we isolated a strain of B. pseudocatenulatum NCU-08 from the feces of centenarians and assessed its impact on aging using a mouse model induced by D-gal. Our study revealed the exceptional probiotic attributes of B. pseudocatenulatum NCU-08. Administration of B. pseudocatenulatum NCU-08 significantly ameliorated age-related memory impairment, motor dysfunction, and anxiety-like behaviors in aging mice (p < 0.01). Moreover, tissue staining analysis demonstrated that B. pseudocatenulatum NCU-08 reduced the intensity of SA-ß-gal-positive in the hippocampus of aging mice. It also reversed pathological damage and structural abnormalities in brain and intestinal tissue. B. pseudocatenulatum NCU-08 inhibited neuroinflammation induced by TLR4/NF-κB (p < 0.01) and preserved the blood-brain barrier integrity by activating the AMPK/Sirt1 pathway (p < 0.05). Furthermore, it mitigated neuronal apoptosis and oxidative stress by upregulating the PI3K/AKT signaling pathway (p < 0.01) and enhancing the activities of antioxidant enzymes, including GSH-Px (p < 0.01), SOD (p < 0.01), and CAT (p < 0.01). Besides, analysis of 16S rRNA sequencing data demonstrated that treatment with B. pseudocatenulatum NCU-08 restored intestinal microbiota homeostasis after senescence. It enhanced the abundance of beneficial bacteria while suppressing the growth of pathogenic microorganisms. In summary, our study unveiled that this novel strain of B. pseudocatenulatum NCU-08 exerts anti-aging effects through regulating the AMPK/Sirt1 pathway and intestinal microbiota. It holds promise as a functional food for promoting anti-aging effects and offers a novel approach to address aging and associated metabolic disorders.

ADNP dysregulates methylation and mitochondrial gene expression in the cerebellum of a Helsmoortel-Van der Aa syndrome autopsy case.

BACKGROUND: Helsmoortel-Van der Aa syndrome is a neurodevelopmental disorder in which patients present with autism, intellectual disability, and frequent extra-neurological features such as feeding and gastrointestinal problems, visual impairments, and cardiac abnormalities. All patients exhibit heterozygous de novo nonsense or frameshift stop mutations in the Activity-Dependent Neuroprotective Protein (ADNP) gene, accounting for a prevalence of 0.2% of all autism cases worldwide. ADNP fulfills an essential chromatin remodeling function during brain development. In this study, we investigated the cerebellum of a died 6-year-old male patient with the c.1676dupA/p.His559Glnfs*3 ADNP mutation. RESULTS: The clinical presentation of the patient was representative of the Helsmoortel-Van der Aa syndrome. During his lifespan, he underwent two liver transplantations after which the child died because of multiple organ failure. An autopsy was performed, and various tissue samples were taken for further analysis. We performed a molecular characterization of the cerebellum, a brain region involved in motor coordination, known for its highest ADNP expression and compared it to an age-matched control subject. Importantly, epigenome-wide analysis of the ADNP cerebellum identified CpG methylation differences and expression of multiple pathways causing neurodevelopmental delay. Interestingly, transcription factor motif enrichment analysis of differentially methylated genes showed that the ADNP binding motif was the most significantly enriched. RNA sequencing of the autopsy brain further identified downregulation of the WNT signaling pathway and autophagy defects as possible causes of neurodevelopmental delay. Ultimately, label-free quantification mass spectrometry identified differentially expressed proteins involved in mitochondrial stress and sirtuin signaling pathways amongst others. Protein-protein interaction analysis further revealed a network including chromatin remodelers (ADNP, SMARCC2, HDAC2 and YY1), autophagy-related proteins (LAMP1, BECN1 and LC3) as well as a key histone deacetylating enzyme SIRT1, involved in mitochondrial energy metabolism. The protein interaction of ADNP with SIRT1 was further biochemically validated through the microtubule-end binding proteins EB1/EB3 by direct co-immunoprecipitation in mouse cerebellum, suggesting important mito-epigenetic crosstalk between chromatin remodeling and mitochondrial energy metabolism linked to autophagy stress responses. This is further supported by mitochondrial activity assays and stainings in patient-derived fibroblasts which suggest mitochondrial dysfunctions in the ADNP deficient human brain. CONCLUSION: This study forms the baseline clinical and molecular characterization of an ADNP autopsy cerebellum, providing novel insights in the disease mechanisms of the Helsmoortel-Van der Aa syndrome. By combining multi-omic and biochemical approaches, we identified a novel SIRT1-EB1/EB3-ADNP protein complex which may contribute to autophagic flux alterations and impaired mitochondrial metabolism in the Helsmoortel-Van der Aa syndrome and holds promise as a new therapeutic target.

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-1ß, 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.

Fisetin alleviates cerebral ischemia/reperfusion injury by regulating Sirt1/Foxc1/Ubqln1 pathway-mediated proteostasis.

BACKGROUND: Cerebral ischemia/reperfusion injury (IRI) is pathologically associated with protein damage. The flavonoid fisetin has good therapeutic effects on cerebral IRI. However, the role of fisetin in regulating protein damage during cerebral IRI development remains unclear. This study investigated the pharmacological effects of fisetin on protein damage during cerebral IRI progression and defined the underlying mechanism of action. METHODS: In vivo and in vitro models of cerebral IRI were established by middle cerebral artery occlusion/reperfusion (MACO/R) and oxygen-glucose deprivation/reperfusion (OGD/R) treatment, respectively. Triphenyl tetrazolium chloride staining was performed to detect cerebral infarct size, and the modified neurologic severity score was used to examine neurological deficits. LDH activity and protein damage were assessed using kits. HT22 cell vitality and apoptosis were examined using CCK-8 assay and TUNEL staining, respectively. Interactions between Foxc1, Ubqln1, Sirt1, and Ezh2 were analyzed using CoIP, ChIP and/or dual-luciferase reporter gene assays. RESULTS: Fisetin alleviated protein damage and ubiquitinated protein aggregation and neuronal death caused by MCAO/R and OGD/R. Ubqln1 knockdown abrogated the inhibitory effect of fisetin on OGD/R-induced protein damage, ubiquitinated protein aggregation, and neuronal death in HT22 cells. Further experiments demonstrated that Foxc1 functions as a transcriptional activator of Ubqln1 and that Sirt1 promotes Foxc1 expression by deacetylating Ezh2 and inhibiting its activity. Furthermore, Sirt1 knockdown abrogated fisetin-mediated biological effects on OGD/R-treated HT22 cells. CONCLUSION: Fisetin improved proteostasis during cerebral IRI by regulating the Sirt1/Foxc1/Ubqln1 signaling axis. Our findings strongly suggest that fisetin-mediated inhibition of protein damage after ischemic stroke is a part of the mechanism through which fisetin is neuroprotective in cerebral IRI.

Melatonin Enhanced Microglia M2 Polarization in Rat Model of Neuro-inflammation Via Regulating ER Stress/PPARδ/SIRT1 Signaling Axis.

Neuro-inflammation involves distinct alterations of microglial phenotypes, containing nocuous pro-inflammatory M1-phenotype and neuroprotective anti-inflammatory M-phenotype. Currently, there is no effective treatment for modulating such alterations. M1/M2 marker of primary microglia influenced by Melatonin were detected via qPCR. Functional activities were explored by western blotting, luciferase activity, EMSA, and ChIP assay. Structure interaction was assessed by molecular docking and LIGPLOT analysis. ER-stress detection was examined by ultrastructure TEM, calapin activity, and ERSE assay. The functional neurobehavioral evaluations were used for investigation of Melatonin on the neuroinflammation in vivo. Melatonin had targeted on Peroxisome Proliferator Activated Receptor Delta (PPARδ) activity, boosted LPS-stimulated alterations in polarization from the M1 to the M2 phenotype, and thereby inhibited NFκB-IKKß activation in primary microglia. The PPARδ agonist L-165,041 or over-expression of PPARδ plasmid (ov-PPARδ) showed similar results. Molecular docking screening, dynamic simulation approaches, and biological studies of Melatonin showed that the activated site was located at PPARδ (phospho-Thr256-PPARδ). Activated microglia had lowered PPARδ activity as well as the downstream SIRT1 formation via enhancing ER-stress. Melatonin, PPARδ agonist and ov-PPARδ all effectively reversed the above-mentioned effects. Melatonin blocked ER-stress by regulating calapin activity and expression in LPS-activated microglia. Additionally, Melatonin or L-165,041 ameliorated the neurobehavioral deficits in LPS-aggravated neuroinflammatory mice through blocking microglia activities, and also promoted phenotype changes to M2-predominant microglia. Melatonin suppressed neuro-inflammation in vitro and in vivo by tuning microglial activation through the ER-stress-dependent PPARδ/SIRT1 signaling cascade. This treatment strategy is an encouraging pharmacological approach for the remedy of neuro-inflammation associated disorders.

Resveratrol prevents cognitive deficits induced by sleep deprivation via modulating sirtuin 1 associated pathways in the hippocampus.

Accumulating evidence confirms that sleep insufficiency is a high risk factor for cognitive impairment, which involves inflammation and synaptic dysfunction. Resveratrol, an agonist of the Sirt1, has demonstrated anti-inflammation and neuroprotective effects in models of Alzheimer's disease, Parkinson's disease, and schizophrenia. However, the beneficial effects of resveratrol on sleep deprivation-induced cognitive deficits and its underlying molecular mechanisms are unclear. In the present study, thirty-two male C57BL/6 J mice were randomly divided into a Control+DMSO group, Control+Resveratrol group, SD+DMSO group, and SD+Resveratrol group. The mice in the SD+Resveratrol group underwent 5 days of sleep deprivation after pretreatment with resveratrol (50 mg/kg) for 2 weeks, while the mice in the SD+DMSO group only underwent sleep deprivation. After sleep deprivation, we evaluated spatial learning and memory function using the Morris water maze test. We used general molecular biology techniques to detect changes in levels of pro-inflammatory cytokines and Sirt1/miR-134 pathway-related synaptic plasticity proteins. We found that resveratrol significantly reversed sleep deprivation-induced learning and memory impairment, elevated interleukin-1ß, interleukin-6, and tumor necrosis factor-α levels, and decreased brain-derived neurotrophic factor, tyrosine kinase receptor B, postsynaptic density protein-95, and synaptophysin levels by activating the Sirt1/miR-134 pathway. In conclusion, resveratrol is a promising agent for preventing sleep deprivation-induced cognitive dysfunction by reducing pro-inflammatory cytokines and improving synaptic function via the Sirt1/miR-134 pathway.

Development and Characterization of a Novel Carbon-11 Labeled Positron Emission Tomography Radiotracer for Neuroimaging of Sirtuin 1 with Benzoxazine-Based Compounds.

Introduction: Sirtuins (SIRTs) comprise a group of histone deacetylase enzymes crucial for regulating metabolic pathways and contributing significantly to various disease mechanisms. Sirtuin 1 (SIRT1), among the seven known mammalian homologs, is extensively investigated and understood, playing a key role in neurodegenerative disorders and cancer. This study focuses on potential as a therapeutic target for conditions such as Parkinson's disease (PD), Huntington's disease (HD), and Alzheimer's disease (AD). Methods: Utilizing positron emission tomography (PET) as a noninvasive molecular imaging modality, we aimed to expedite the validation of a promising sirtuin 1 inhibitor for clinical trials. However, the absence of a validated sirtuin 1 PET radiotracer impedes clinical translation. We present the development of [11C]1, and 11C-labeled benzoxazine-based derivative, as a lead imaging probe. The radiosynthesis of [11C]1 resulted in a radiochemical yield of 31 ± 4%. Results: Baseline studies demonstrated that [11C]1 exhibited excellent blood-brain barrier (BBB) penetration capability, with uniform accumulation throughout various brain regions. Self-blocking studies revealed that introducing an unlabeled compound 1, effectively blocking sirtuin 1, led to a substantial reduction in whole-brain uptake, emphasizing the in vivo specificity of [11C]1 for sirtuin 1. Discussion: The development of [11C]1 provides a valuable tool for noninvasive imaging investigations in rodent models with aberrant sirtuin 1 expression. This novel radiotracer holds promise for advancing our understanding of sirtuin 1's role in disease mechanisms and may facilitate the validation of sirtuin 1 inhibitors in clinical trials.

Exosomes from senescent epithelial cells activate pulmonary fibroblasts via the miR-217-5p/Sirt1 axis in paraquat-induced pulmonary fibrosis.

BACKGROUND: Paraquat (PQ) is a widely used and highly toxic herbicide that poses a significant risk to human health. The main consequence of PQ poisoning is pulmonary fibrosis, which can result in respiratory failure and potentially death. Our research aims to uncover a crucial mechanism in which PQ poisoning induces senescence in epithelial cells, ultimately regulating the activation of pulmonary fibroblasts through the exosomal pathway. METHODS: Cellular senescence was determined by immunohistochemistry and SA-ß-Gal staining. The expression of miRNAs was measured by qPCR. Pulmonary fibroblasts treated with specific siRNA of SIRT1 or LV-SIRT1 were used to analysis senescent exosomes-mediated fibroblasts activation. Luciferase reporter assay and western blot were performed to elucidated the underlying molecular mechanisms. The effects of miR-217-5p antagomir on pulmonary fibrosis were assessed in PQ-poisoned mice models. RESULTS: Impairing the secretion of exosomes effectively mitigates the harmful effects of senescent epithelial cells on pulmonary fibroblasts, offering protection against PQ-induced pulmonary fibrosis in mice. Additionally, we have identified a remarkable elevation of miR-217-5p expression in the exosomes of PQ-treated epithelial cells, which specifically contributes to fibroblasts activation via targeted inhibition of SIRT1, a protein involved in cellular stress response. Remarkably, suppression of miR-217-5p effectively impaired senescent epithelial cells-induced fibroblasts activation. Further investigation has revealed that miR-217-5p attenuated SIRT1 expression and subsequently resulted in enhanced acetylation of ß-catenin and Wnt signaling activation. CONCLUSION: These findings highlight a potential strategy for the treatment of pulmonary fibrosis induced by PQ poisoning. Disrupting the communication between senescent epithelial cells and pulmonary fibroblasts, particularly by targeting the miR-217-5p/SIRT1/ß-catenin axis, may be able to alleviate the effects of PQ poisoning on the lungs.

Ningxin-Tongyu-Zishen formula alleviates the senescence of granulosa cells on D-galactose-induced premature ovarian insufficiency mice.

Ningxin-Tongyu-Zishen formula (NTZF) is a clinical experience formula for the treatment of premature ovarian insufficiency (POI) in traditional Chinese medicine (TCM), and the potential mechanism is unknown. For in vivo experiments, POI mouse models (C57BL/6 mice), were constructed by subcutaneous injection of D-galactose (D-gal, 200 mg/kg). After treatment of NTZF (10.14, 20.27, 40.54 g/kg;) or estradiol valerate (0.15 mg/kg), ovarian function, oxidative stress (OS) and protein expression of Sirt1/p53 were evaluated. For in vitro experiments, H2O2 (200 µM) was used to treat KGN to construct ovarian granulosa cells (OGCs) cell senescence model. Pretreatment with NTZF (1.06 mg/mL) or p53 inhibitor (Pifithrin-α, 1 µM) was performed before induction of senescence, and further evaluated the cell senescence, OS, mRNA and protein expression of Sirt1/p53. In vivo, NTZF improved ovarian function, alleviated OS and Sirt1/p53 signaling abnormalities in POI mice. In vitro experiments showed that NTZF reduced the level of OS and alleviated the senescence of H2O2-induced KGN. In addition, NTZF activated the protein expression of Sirt1, inhibited the mRNA transcription and protein expression of p53 and p21. Alleviating OGCs senescence and protecting ovarian function through Sirt1/p53 is one of the potential mechanisms of NTZF in the treatment of POI.

Protective Effect of Que Zui Tea on d-Galactose-Induced Oxidative Stress Damage in Mice via Regulating SIRT1/Nrf2 Signaling Pathway.

Que Zui tea (QT) is an important herbal tea in the diet of the 'Yi' people, an ethnic group in China, and it has shown significant antioxidant, anti-inflammatory, and hepatoprotective effects in vitro. This study aims to explore the protective effects of the aqueous-ethanol extract (QE) taken from QT against ᴅ-galactose (ᴅ-gal)-induced oxidative stress damage in mice and its potential mechanisms. QE was identified as UHPLC-HRMS/MS for its chemical composition and possible bioactive substances. Thus, QE is rich in phenolic and flavonoid compounds. Twelve compounds were identified, the main components of which were chlorogenic acid, quinic acid, and 6'-O-caffeoylarbutin. Histopathological and biochemical analysis revealed that QE significantly alleviated brain, liver, and kidney damage in ᴅ-gal-treated mice. Moreover, QE remarkably attenuated oxidative stress by activating the Nrf2/HO-1 pathway to increase the expression of antioxidant indexes, including GSH, GSH-Px, CAT, SOD, and T-AOC. In addition, QE administration could inhibit the IL-1ß and IL-6 levels, which suppress the inflammatory response. QE could noticeably alleviate apoptosis by inhibiting the expressions of Caspase-3 and Bax proteins in the brains, livers, and kidneys of mice. The anti-apoptosis mechanism may be related to the upregulation of the SIRT1 protein and the downregulation of the p53 protein induced by QE in the brain, liver, and kidney tissues of mice. Molecular docking analysis demonstrated that the main components of QE, 6'-O-caffeoylarbutin, chlorogenic acid, quinic acid, and robustaside A, had good binding ability with Nrf2 and SIRT1 proteins. The present study indicated that QE could alleviate ᴅ-gal-induced brain, liver and kidney damage in mice by inhibiting the oxidative stress and cell apoptosis; additionally, the potential mechanism may be associated with the SIRT1/Nrf2 signaling pathway.

Inhibitory protein-protein interactions of the SIRT1 deacetylase are choreographed by post-translational modification.

Regulation of SIRT1 activity is vital to energy homeostasis and plays important roles in many diseases. We previously showed that insulin triggers the epigenetic regulator DBC1 to prime SIRT1 for repression by the multifunctional trafficking protein PACS-2. Here, we show that liver DBC1/PACS-2 regulates the diurnal inhibition of SIRT1, which is critically important for insulin-dependent switch in fuel metabolism from fat to glucose oxidation. We present the x-ray structure of the DBC1 S1-like domain that binds SIRT1 and an NMR characterization of how the SIRT1 N-terminal region engages DBC1. This interaction is inhibited by acetylation of K112 of DBC1 and stimulated by the insulin-dependent phosphorylation of human SIRT1 at S162 and S172, catalyzed sequentially by CK2 and GSK3, resulting in the PACS-2-dependent inhibition of nuclear SIRT1 enzymatic activity and translocation of the deacetylase in the cytoplasm. Finally, we discuss how defects in the DBC1/PACS-2-controlled SIRT1 inhibitory pathway are associated with disease, including obesity and non-alcoholic fatty liver disease.

Inhibition of SIRT1 in the nucleus accumbens attenuates heroin addiction-related behavior by decreasing D1 neuronal autophagy.

This study aimed to investigate the effects of SIRT1 modulation on heroin addiction-like behavior and its possible biological mechanisms. Wild-type C57BL/6J and Sirt1loxp/loxp D1-Cre mice were used in this experiment, and Sirt1 loxp/loxp D1-Cre(-) mice were used as a control for conditional knockout mice. Mice were divided into saline control and heroin-dependent groups. Behavioral methods were used to record the withdrawal response, conditioned place preference (CPP) changes, and open field test results. Transmission electron microscopy (TEM) was used to observe the structure of autophagosomes in nucleus accumbens (NAc) neurons. The expression of SIRT1 and autophagy-related proteins and genes, such as LC3Ⅱ, ATG5 , and ATG7 , was detected in the NAc of each mouse group via western blot, real-time quantitative PCR (qPCR) analyzes, and immunofluorescence. The results of this experiment showed that compared with the saline group, mice in the wild-type heroin-dependent group showed marked withdrawal symptoms, with more autophagosomes observed in NAc via TEM. Compared with wild-type and Sirt1loxp/loxp D1-Cre(-) heroin-dependent groups, CPP formation was found to be reduced in the conditional knockout mouse group, with a significant decrease in spontaneous activity. Western blot, qPCR, and immunofluorescence results indicated that the expression of LC3Ⅱ, ATG-5, and ATG-7 was significantly reduced in the NAc of the Sirt1loxp/loxp D1-Cre(+) group. It was still, however, higher than that in the saline control group. These results suggest that inhibition of Sirt1 expression may prevent heroin-induced addiction-related behaviors via reducing D1 neuronal autophagy.

Synergistic effects of tetramethylpyrazine and astragaloside IV on spinal cord injury via alteration of astrocyte A1/A2 polarization through the Sirt1-NF-κB pathway.

OBJECTIVE: Reactive astrocytes are hallmarks of traumatic spinal cord injury (T-SCI) and are associated with neuropathic pain (NP). Mediating the functional phenotype of reactive astrocytes helps neural repair and ameliorates NP in T-SCI. Here, we aimed to explore the role of tetramethylpyrazine (TMPZ) and astragaloside IV (AGS-IV) in astrocyte polarization and the underlying molecular mechanism in T-SCI. METHODS: Primary cultured astrocytes from mice were treated with LPS or conditioned medium from "M1" polarized microglia (M1-CM), followed by TMPZ and/or AGS-IV administration. The expression levels of "A1" astrocyte-specific markers (including C3, GBP2, Serping1, iNOS), "A2" astrocyte-specific markers (including S100a10 and PTX3), Sirt1 and NF-κB were detected via western blotting. TNF-α and IL-1ß levels were detected via ELISA. RT-PCR was used to evaluate OIP5-AS1 and miR-34a expression. si-OIP5-AS1 or the Sirt1 inhibitor EX-527 was administered to astrocytes. A spinal cord injury (SCI) model was constructed in Sprague-Dawley (SD) rats. Alterations in astrocytic "A1/A2" polarization in the spinal cord tissues were evaluated. RESULTS: LPS and M1-CM induced "A1" polarization of primary astrocytes. TMPZ and ASG IV could substantially reduce the expression of "A1"-related biomarkers but enhance "A2"-related biomarkers. OIP5-AS1 and Sirt1 levels were reduced in "A1"-polarized astrocytes, while miR-34a and p-NF-κB p65 were elevated. TMPZ and ASG IV enhanced OIP5-AS1 and Sirt1 levels and, in contrast, attenuated the changes in miR-34a and p-NF-κB p65 levels. Notably, the TMPZ and ASG IV combination had stronger effects on astrocyte polarization than the single treatment with TMPZ or ASG IV. OIP5-AS1 knockdown and Sirt1 inhibition both reversed the regulatory effects of TMPZ and ASG IV in astrocytic polarization. According to the in vivo experiments, the expression of "A1"-associated markers was enhanced in the spinal cords of SCI rats. The TMPZ and ASG IV combination reduced astrocytic "A1" polarization and enhanced astrocytic "A2" polarization. The expression of lncRNA OIP5-AS1 and Sirt1 was enhanced by TMPZ and ASG IV, while that of miR-34a and p-NF-κB p65 was inhibited. CONCLUSION: The combination of TMPZ and ASG IV can ameliorate dysregulated astrocytic polarization induced by spinal cord injury by affecting the lncRNA OIP5-AS1-Sirt1-NF-κB pathway.

Roles of Sirt1 and its modulators in diabetic microangiopathy: A review.

Diabetic vascular complications include diabetic macroangiopathy and diabetic microangiopathy. Diabetic microangiopathy is characterised by impaired microvascular endothelial function, basement membrane thickening, and microthrombosis, which may promote renal, ocular, cardiac, and peripheral system damage in diabetic patients. Therefore, new preventive and therapeutic strategies are urgently required. Sirt1, a member of the nicotinamide adenine dinucleotide-dependent histone deacetylase class III family, regulates different organ growth and development, oxidative stress, mitochondrial function, metabolism, inflammation, and aging. Sirt1 is downregulated in vascular injury and microangiopathy. Moreover, its expression and distribution in different organs correlate with age and play critical regulatory roles in oxidative stress and inflammation. This review introduces the background of diabetic microangiopathy and the main functions of Sirt1. Then, the relationship between Sirt1 and different diabetic microangiopathies and the regulatory roles mediated by different cells are described. Finally, we summarize the modulators that target Sirt1 to ameliorate diabetic microangiopathy as an essential preventive and therapeutic measure for diabetic microangiopathy. In conclusion, targeting Sirt1 may be a new therapeutic strategy for diabetic microangiopathy.