SIRT1 Expression Research Articles

Anti-Obesity Effects of Calcium Fructoborate by Inhibiting Adipogenesis and Increasing SIRT's Expression in 3T3-L1 Cells.

Obesity is a global public health problem that can lead to mortality and morbidity. Studies on the pathophysiology of obesity for effective and safe treatments are focused on the mechanisms of adipogenesis. The association between boron treatment and weight loss has been reported, but its anti-adipogenic mechanisms and effects on preadipocytes remain unclear. This study aims to investigate the effects of boron compounds boric acid (BA) and calcium fructoborate (CaFB) on adipogenesis using the most widely used in vitro 3T3-L1 cellular model. In our study, cytotoxicity, Oil Red O (ORO), gene and protein expression analyses and cellular NAD measurements of boron compounds were performed. Peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer binding protein α (C/EBPα) transcription factors are the main regulators of adipogenesis, and boron compounds affect them at gene and protein levels by showing anti-obesity effects. This is the first study to show that CaFB has anti-obesity properties in mouse adipocytes. Sirtuins, known as the longevity genes, were also activated from boron treatment. Results of this research provide new basic knowledge and insights into the effect of boron-based compounds on obesity. It also offers potential prospects for the development of effective treatment and/or supportive treatment methods.

MiR-204-5p regulates SIRT1 to promote the endoplasmic reticulum stress-induced apoptosis of inner ear cells in C57BL/6 mice with hearing loss.

This study investigated the effect of miR-204-5p-mediated silencing of SIRT1 on the development of deafness in C57BL/6 mice and the roles of miR-204-5p and SIRT1 in deafness. Auditory brainstem response recordings, H&E staining, and immunohistochemistry were used to observe changes in hearing function and cochlear tissue morphology in 2-month-old and 15-month-old C57BL/6 mice. A senescence model was induced using H2O2 in inner ear cells (HEI-OC1). Changes in HEI-OC1 cell proliferation were detected using the CCK-8 assay, whereas flow cytometry was used to detect changes in apoptosis. MiR-204-5p expression was measured via RT‒qPCR. The SIRT1 agonist RSV and a miR-204-5p inhibitor were used to study changes in ER stress (ERS), proliferation, and apoptosis in HEI-OC1 cells. Western blotting was performed to detect changes in ATF4, CHOP, SIRT1, PERK, p-PERK, Bax, and Bcl-2 protein levels. A dual-luciferase reporter gene assay was carried out to assess the ability of miR-204-5p to target SIRT1. Relative miR-204-5p expression levels in the cochleae of aged C57BL/6 mice increased, whereas SIRT1 expression levels decreased, and miR-204-5p and SIRT1 expression levels were negatively correlated. ERS and increased 8-OHDG levels were observed in aged C57BL/6 mice. In a model of inner ear cell aging, H2O2 treatment induced increases in miR-204-5p expression and ERS-mediated apoptosis. MiR-204-5p was found to target SIRT1 and inhibit its expression. SIRT1 activation and a miR-204-5p inhibitor promoted HEI-OC1 cell proliferation and reduced apoptosis. The miR-204-5p inhibitor regulated expression of the ERS proteins PERK, ATF4, and CHOP to upregulate Bcl-2 and downregulate Bax. This study identified the roles of miR-204-5p and SIRT1 in deafness in C57BL/6 mice and investigated the loss of cochlear outer hair cells and the involvement of apoptosis and ERS in deafness.

Estrogen Regulates Ca2+ to Promote Mitochondrial Function Through G-Protein-Coupled Estrogen Receptors During Oocyte Maturation

Estrogen is a steroid hormone that plays a key role in regulating many physiological processes, such as follicle activation and development and oocyte maturation in mammals. Ca2+ is crucial in oogenesis, oocyte maturation, ovulation, and fertilization. However, the mechanism by which estrogen regulates Ca2+ during oocyte maturation in mice has not been reported. This study revealed that Ca2+ levels in oocytes significantly increase during the 4–12 h period in vitro. Oocytes treated with 0.1 µM estrogen and 1 µM G1, a G-protein-coupled estrogen receptor (GPER) agonist, showed significantly increased Ca2+ levels, while treatment with 1 µM G15, an antagonist of GPER, significantly decreased Ca2+ levels. Notably, estrogen regulates Ca2+ in oocytes through the GPER pathway and promotes the expression of the Ca2+-producing protein EPAC1. In addition, estrogen alleviates the inhibitory effect of the Ca2+ chelator BAPTA-AM during oocyte maturation by promoting Ca2+ production. Furthermore, estrogen can promote the expression of the mitochondrial generation-associated protein SIRT1 through the GPER pathway, alleviate mitochondrial oxidative damage caused by BAPTA-AM, and restore the mitochondrial membrane potential level. Collectively, this study demonstrates that estrogen can regulate Ca2+ through the GPER-EPAC1 pathway and promote the expression of SIRT1, which promotes oocyte mitochondrial function during oocyte maturation.

CSIG-28. DISSECTING THE FUNCTIONAL IMPAIRMENT OF WILD-TYPE P53 IN HUMAN GLIOBLASTOMA

Abstract Glioblastoma (GBM) is the most common malignant brain tumor in adults and is characterized by heterogeneous nature, invasive potential, and poor treatment response. Work from The Cancer Genome Atlas (TCGA) identified the tumor suppressor gene TP53 as a GBM driver. In contrast to several cancers, only ~35% of GBM cases carry mutations in TP53. Work from our lab showed that TP53 mutations emerge as ‘late’ events during GBM growth. Therefore, we hypothesized that wild-type (wt) p53 function is impaired in GBM. We used the TCGA data of 591 GBM patients to compare the clinical and molecular characteristics of wt and mutant TP53 patients. Gene expression data were analyzed to compare the correlation of TP53 with the expression of key p53 regulators and identify differentially expressed regulators between our groups. Furthermore, we evaluated the expression of p53 and selected regulators in patient-derived cells (PDCs) and control lines with known TP53 status. Our results show that wt TP53 patients live less than mutant patients and both groups respond similarly to treatment. No differences in age, sex, race, TP53 levels, and MGMT methylation status were observed between the groups. Gene expression analyses revealed that MAPK8, a p53 activator, negatively correlates with TP53 in the wt group. Moreover, ~21% of p53 regulators are differentially expressed between wt and mutant patients. Among these, we selected SIRT3, a p53 repressor, for experimental validation. We verified the p53 genetic status of PDCs through western blot and confirmed Sirt3 expression in wt and mutant TP53 PDCs. By CRISPR-Cas9-based genomic editing, we are currently evaluating the impact of SIRT3 knockout in GBM-PDC and patient-derived xenografts. We expect that SIRT3 knockout will restore p53 function in the wt group. In conclusion, our results suggest that p53 function is impaired in wt patients and provide insights into mechanisms affecting its activity.

17β-estradiol Ameliorates Postoperative Cognitive Dysfunction in Aged Mice via miR-138-5p/SIRT1/HMGB1 Pathway.

Postoperative cognitive dysfunction (POCD) is a common neurological complication in older patients and correlated with adverse outcomes.17β-estradiol treatment was reported to provide neuroprotective protection in various neurologic disorders, but whether it attenuated POCD was unknown. The purpose of this study was to explore the effects of 17β-estradiol treatment on POCD and the mechanisms. We generated a POCD model in 15-month-old mice via laparotomy, followed by subcutaneous injection of 17β-estradiol, intraperitoneal injection of EX527 (a SIRT1 inhibitor) or bilateral hippocampal injection of miR-138-5p-agomir. Morris water maze test and open field test were applied to evaluate the cognitive function. The neuronal apoptosis in hippocampus was detected using TUNEL assay. Meanwhile, the levels of IL-1β and microglia activation were measured by ELISA and immunofluorescence, respectively. Western blot was utilized to assess the expression of SIRT1 and HMGB1 protein, and gene expression of miR-138-5p was determined through qRT-PCR. Behavioral tests showed that 17β-estradiol treatment improved cognitive function in aged POCD mice. In addition, 17β-estradiol attenuated neuronal apoptosis and microglia activation as well as IL-1β expression in hippocampus. Nonetheless, injection with EX527 abolished the beneficial impacts of 17β-estradiol against POCD. Furthermore, miR-138-5p was verified to bind with SIRT1, which regulated the expression of HMGB1. After treatment with 17β-estradiol, miR-138-5p expression was reduced in hippocampus, and the neuroprotective influence of 17β-estradiol on aged POCD mice was reversed after administration of miR-138-5p-agomir. 17β-estradiol treatment exerted neuroprotection effects on POCD in aged mice, which might be relevant to alleviating neuroinflammation via miR-138-5p/SIRT1/HMGB1 pathway.

Alanyl-Glutamine Inhibits the Epithelial-Mesenchymal Transition of Airway Epithelial Cells in Asthmatic Mice via DPP4-SIRT1 Pathway

Introduction: Alanyl-glutamine (Ala-Gln) is a compound known for its protective effects in various tissue injuries. However, its role in asthma-related lung injuries remains underexplored. This study investigates the mechanisms by which Ala-Gln modulates sDPP4-induced airway epithelial-mesenchymal transition and ovalbumin (OVA)-induced asthma in a mouse model. Methods: An asthma model was established in female C57BL/6 J mice by using OVA. CD4+ T cells and bronchial epithelial cells (BECs) were isolated from the spleen and bronchi of the mice, respectively. Interventions included recombinant sCD26/sDPP4 protein, Ala-Gln, and EX527 (a SIRT1 inhibitor). Flow cytometry was used to assess Th17 and Treg cell populations. Mice were treated with Ala-Gln, EX527, and budesonide (BUD). Histopathological changes in lung tissues were evaluated using hematoxylin-eosin and Masson staining. White blood cell counts were measured with a hematology analyzer. The expression levels of DPP4, IL-17, SIRT1, SMAD2/3, N-cadherin, E-cadherin, MMP9, and α-SMA proteins were analyzed. Results: Treatment with recombinant sCD26/sDPP4 resulted in decreased E-cadherin expression in BECs and increased levels of α-SMA, MMP9, and N-cadherin, effects that were mitigated by Ala-Gln. Ala-Gln also prevented the reduction in SIRT1 expression in BECs and the increase in Th17 cell differentiation induced by recombinant sCD26/sDPP4. EX527 administration alongside Ala-Gln reversed these changes and enhanced the phosphorylation of SMAD2/3 through SIRT1 signaling. BUD alone reduced inflammation and fibrosis in bronchial tissue and lowered the Th17/Treg ratio in peribronchial lymph nodes. The therapeutic effect of BUD was further improved with concurrent Ala-Gln treatment. Conclusion: Ala-Gln can inhibit BEC fibrosis and Th17 cell differentiation mediated by recombinant sCD26/sDPP4 through the SIRT1 pathway. Combined with BUD, Ala-Gln enhanced therapeutic efficacy in OVA-induced asthma in mice, which could offer improved outcomes for asthmatic patients with elevated DPP4 levels.

HnRNPA2B1 deacetylation by SIRT6 restrains local transcription and safeguards genome stability.

Repair of double strand breaks (DSBs) by RNA-binding proteins (RBPs) is vital for ensuring genome integrity. DSB repair is accompanied by local transcriptional repression in the vicinity of transcriptionally active genes, but the mechanism by which RBPs regulate transcriptional regulation is unclear. Here, we demonstrated that RBP hnRNPA2B1 functions as a RNA polymerase-associated factor that stabilizes the transcription complex under physiological conditions. Following a DSB, hnRNPA2B1 is released from damaged chromatin, reducing the efficiency of RNAPII complex assembly, leading to local transcriptional repression. Mechanistically, SIRT6 deacetylates hnRNPA2B1 at K113/173 residues, enforcing its rapid detachment from DSBs. This process disrupts the integrity of the RNAPII complex on active chromatin, which is a pre-requisite for transient but complete repression of local transcription. Functionally, the overexpression of an acetylation mimic stabilizes the transcription complex and facilitates the functioning of the transcription machinery. hnRNPA2B1 acetylation status was negatively correlated with SIRT6 expression, and acetylation mimic enhanced radio-sensitivity in vivo. Our findings demonstrate that hnRNPA2B1 is crucial for transcriptional repression. We have uncovered the missing link between DSB repair and transcriptional regulation in genome stability maintenance, highlighting the potential of hnRNPA2B1 as a therapeutic target.

β-1,3-glucan from Euglena gracilis: a promising epidrug targeting epigenetic regulators PRMTs and SIRTs for therapeutic applications in ovarian cancer

Natural products serve as a valuable resource in drug discovery and the identification of bioactive molecules in the field of epimedicine, which targets epigenetic regulator enzymes through epidrugs. In this study, β-1,3-glucan (BG), a natural storage polysaccharide in Euglena gracilis, a well-known immunostimulatory agent, is propounded as a promising epidrug. To elucidate the therapeutic efficacy of BG against ovarian cancer, the molecular interactions between BG and epigenetic regulators, Protein Arginine Methyltransferases (PRMTs) and Sirtuins (SIRTs) were investigated using computational methods followed by in vitro gene expression studies in SKOV-3 ovarian cancer cell line. The binding energies of PRMT5 and SIRT5 against BG were observed as −65.5 and −68.2 kcal/mol, respectively. The in vitro cytotoxic effects of BG against human ovarian cancer cell line, SKOV-3 showed an IC50 of 150 µg/mL at 48 h. Significant epigenetic modifications were observed to be influenced by BG which increased the gene expression of PRMT5, SIRT5 and Nrf2 to 0.3, 0.5, and 0.7 fold-change respectively, while the Nrf1/2 plasmid showed reduced reporter activity by 29%. Collectively, both in silico and in vitro studies provided valuable insights into the epigenetic regulation of PRMT5 and SIRT5 by BG via Nrf1/2. Nonetheless, further preclinical and clinical investigations are essential to validate the therapeutic properties of BG as an epidrug against ovarian cancer.

Irisin Attenuates Hepatic Stellate Cell Activation and Liver Fibrosis in Bile Duct Ligation Mice Model and Improves Mitochondrial Dysfunction.

Liver fibrosis is a common outcome of chronic liver disease and is primarily driven by hepatic stellate cell (HSC) activation. Irisin, a myokine released during physical exercise, is beneficial for metabolic disorders and mitochondrial dysfunction. This study aimed to explore the effects of irisin on liver fibrosis in HSCs, a bile duct ligation (BDL) mouse model, and the associated mitochondrial dysfunction. In vitro experiments utilized LX-2 cells, a human HSC line, stimulated with transforming growth factor-β1 (TGF-β1), a major regulator of HSC fibrosis, with or without irisin. Mitochondrial function was assessed using mitochondrial fission markers, transmission electron microscopy, mitochondrial membrane potential, and adenosine triphosphate (ATP) production. In vivo, liver fibrosis was induced in mice via BDL, followed by daily intraperitoneal injections of irisin (100 μg/kg/day) for 10 days. In vitro, irisin mitigated HSC activation and reduced reactive oxygen species associated with the TGF-β1/Smad signaling pathway. Irisin restored TGF-β1-induced increases in fission markers (Fis1, p-DRP1) and reversed the decreased expression of TFAM and SIRT3. Additionally, irisin restored mitochondrial membrane potential and ATP production lowered by TGF-β1 treatment. In vivo, irisin ameliorated the elevated liver-to-body weight ratio induced by BDL and alleviated liver fibrosis, as evidenced by Masson's trichrome staining. Irisin also improved mitochondrial dysfunction induced by BDL surgery. Irisin effectively attenuated HSC activation, ameliorated liver fibrosis in BDL mice, and improved associated mitochondrial dysfunction. These findings highlight the therapeutic potential of irisin for the treatment of liver fibrosis.

Photobiomodulation Therapy at 660 nm Inhibits Hippocampal Neuroinflammation in a Lipopolysaccharide-Challenged Rat Model

Background/Objectives: Neuroinflammation is associated with the progression of various brain diseases, and the management of neuroinflammation-induced neural damage is a crucial aspect of treating neurological disorders. This study investigated the anti-inflammatory efficacy of photobiomodulation therapy (PBMT) using 660 nm phototherapy in a rat model with lipopolysaccharide (LPS)-induced neuroinflammation. Methods: We induced inflammation in rat brains via intraperitoneal injection of LPS and subjected the treatment group to 660 nm phototherapy to examine its protective effect against hippocampal damage based on pathological, histological, and immunohistochemical tissue analyses. Results: The 660 nm treated rats showed a significant decrease in hippocampal structural damage and cell death compared to the LPS-treated group. We observed reduced expression of the inflammation markers GFAP, TNF-α, and IL-1β in the hippocampus of the treatment group, and an increase in SIRT1 expression across all hippocampal regions. Conclusions: This study presents a promising method for controlling neuroinflammation and providing neuroprotection and inflammation relief. PBMT represents a non-invasive therapeutic approach with minimal side effects ensured through the proper control of light irradiation.

SIRT3 mitigates high glucose-induced damage in retinal microvascular endothelial cells via OPA1-mediated mitochondrial dynamics

Oxidative stress in endothelial cells is pivotal in diabetic retinopathy (DR), with mitochondrial homeostasis being crucial to mitigate this stress. This study explored the roles of mitochondrial sirtuins (SIRTs) in high glucose (HG)-induced oxidative stress, related endothelial impairment, and mitochondrial homeostasis damage in rat retinal microvascular endothelial cells (RMECs). RMECs were cultured under HG or equivalent osmotic conditions. Cell viability was assessed using the Cell Counting Kit-8 assay, whereas cell death and survival were determined via calcein-AM/propidium iodide double staining. Reactive oxygen species (ROS) levels were measured using 2′,7′-dichlorofluorescein fluorescence. Expression of mitochondrial SIRTs3-5 and key mitochondrial homeostasis molecules was quantified by the quantitative real-time polymerase chain reaction and confirmed by western blotting. Mitochondrial morphology was evaluated using electron microscopy and the MitoTracker fluorescent probe. A SIRT3-overexpressing RMEC line was constructed to assess the role of SIRT3 in oxidative stress and mitochondrial dynamics. After 48 h of HG exposure, cell viability was significantly reduced, with a concomitant increase in cell death and ROS levels, alongside a marked decrease in SIRT3 expression and molecules associated with mitochondrial dynamics. SIRT3 overexpression reversed these effects, particularly increasing the mitochondrial fusion-related molecule, optic atrophy 1 (OPA1). However, the OPA1 inhibitor, MYLS22, blocked the protective effect of SIRT3, leading to more dead cells, a higher ROS level, and intensified mitochondrial fragmentation. These results suggest that SIRT3 is involved in HG-induced imbalanced mitochondrial dynamics of endothelial cells in DR, potentially through the OPA1 pathway.

SIRT2 deacetylates and decreases the expression of FOXM1 in colon cancer.

New FOXM1-specific inhibitors with the potential to be used for therapeutic purposes are under extensive research. We hypothesized that deacetylation of FOXM1 would decrease protein expression, thus providing novel therapeutic management of colon cancers. Immunostaining was used to determine FOXM1 and SIRT2 expressions in human colon cancer tissue microarrays (n = 90) from Stage I to Stage IV. SIRT2-FOXM1 interaction was evaluated in colon cancer cells using immunoprecipitation. Deacetylation of FOXM1 via SIRT2 was determined using in vitro deacetylation assays. FOXM1 could be hyper-acetylated when p300 and pCAF histone acetyltransferases were administered alongside deacetylase inhibitors. We detected that SIRT2 and FOXM1 physically interacted, and SIRT2 deacetylated FOXM1 in vitro. SIRT2 overexpression led to a significant decrease while knockdown of SIRT2 increased the FOXM1 expression in HCT116 human colon carcinoma cells. In the analysis of 90 human colorectal cancer samples, high SIRT2 expression was observed in about 49% of colorectal cancer, intermediate in 29%, and low or no staining in 22%. Strong SIRT2 expression was found to be negatively associated with the FOXM1 staining in our clinical cohort. This study reveals a molecular interaction and association between SIRT2 and FOXM1 expression in colon cancer cell lines and human colon cancer samples, and suggests that targeting SIRT2 activity using small molecule modulators may be a promising therapeutic approach for colorectal cancer.

Nampt/SIRT2/LDHA pathway-mediated lactate production regulates follicular dysplasia in polycystic ovary syndrome

Decreased nicotinamide adenine dinucleotide (NAD+) content has been shown to contribute to metabolic dysfunction during aging, including polycystic ovary syndrome (PCOS). However, the effect of NAD+ on ovulatory dysfunction in PCOS by regulating glycolysis has not been reported. Based on the observations of granulosa cells (GCs) transcriptome data from the Gene Expression Omnibus (GEO) database, the signal pathways including glycolysis and nicotinate-nicotinamide metabolism were significantly enriched, and most genes of the above pathway like LDHA and SIRT2 were down-regulated in PCOS patients. Therefore, the PCOS rat model was established by combining letrozole with a high-fat diet (HFD), we demonstrate that in vivo supplementation of nicotinamide mononucleotide (NMN) significantly improves the ovulatory dysfunction by facilitating the follicular development, promoting luteal formation, as well the fertility in PCOS rats. Furthermore, target energy metabolomics and transcriptome results showed that NMN supplementation ameliorates the lactate production by activating glycolytic process in the ovary. In vitro, when NAD+ synthesis and SIRT2 expression were inhibited, lactate content in KGN cells was decreased and LDHA expression was significantly inhibited. We confirmed that FK866 can enhance the acetylation of LDHA on 293T cells by Co-immunoprecipitation (Co-IP) assay. We also observed that inhibition of NAD+ synthesis can reduce the activity and increase the apoptosis of KGN cells. Overall, these benefits of NMN were elucidated and the Nampt/SIRT2/LDHA pathway mediated lactate production in granulosa cells played an important role in the improvement of follicular development disorders in PCOS. This study will provide experimental evidence for the clinical application of NMN in the treatment of PCOS in the future.

Hemin attenuates bleomycin-induced lung fibrosis in mice by regulating the TGF-β1/MAPK and AMPK/SIRT1/PGC-1α/HO-1/NF-κB pathways.

The objective of this study was to investigate the protective effect and potential mechanism of action of hemin on bleomycin-induced pulmonary fibrosis in mice. Male C57BL/6 mice were randomly divided into control, bleomycin and bleomycin + hemin groups. Mice in the bleomycin and bleomycin + hemin groups were injected intratracheally with bleomycin to establish the pulmonary fibrosis model. The bleomycin + hemin group mice were injected intraperitoneally with hemin starting 7 days before modeling until the end of Day 21 after modeling. Pathological changes in lung tissue were assessed by HE and Masson staining. Malondialdehyde (MDA), superoxide dismutase (SOD) and catalase (CAT) levels were determined in lung tissue. Immunohistochemistry was performed to assess the expression of α-SMA and collagen I. The serum levels of IL-6 and TNF-α were measured via ELISA. Western blotting was used to determine the expression of TGF-β1, SIRT1, PGC-1α and HO-1 and the phosphorylation levels of p38, ERK1/2, JNK, AMPK and NF-κB p65 in lung tissue. Hemin significantly reduced lung indices, increased terminal body weight. It also significantly increased SOD and CAT activities; decreased MDA, IL-6 and TNF-α levels; reduced the levels of α-SMA and collagen I-positive cells; upregulated SIRT1, PGC-1α and HO-1 expression; promoted AMPK phosphorylation; and downregulated TGF-β1 expression and p38, ERK1/2, JNK and NF-κB p65 phosphorylation. Hemin might attenuate oxidative damage and inflammatory responses and reduces extracellular matrix deposition by regulating the expression and phosphorylation of proteins associated with the TGF-β1/MAPK and AMPK/SIRT1/PGC-1α/HO-1/NF-κB pathways, thereby alleviating bleomycin-induced pulmonary fibrosis.

Buyang Huanwu Decoction restores the balance of mitochondrial dynamics after cerebral ischemia-reperfusion through calcium overload reduction by the PKCε-Nampt-Sirt5 axis

Ethnopharmacological relevanceStroke is a common condition that poses a significant threat to human health. Buyang Huanwu Decoction (BYHWD) is a traditional treatment used for stroke management. However, the exact mechanism by which BYHWD mitigates cerebral ischemia-reperfusion by regulating calcium overload and restoring mitochondrial function is not yet fully understood. AimThe objective of this research was to examine the neuroprotective properties of BYHWD in reducing the damage produced by cerebral ischemia/reperfusion (I/R) injury via the modulation of calcium overload and mitochondrial dynamics (MD). MethodsMCAO/R model success was evaluated via PSI laser scatter flowmetry. The neurological function scores were assessed. The cerebral infarct (CI) volume was detected via TTC staining. NeuN expression was detected via immunohistochemistry, and degenerated neurons were observed via FJC staining. The mitochondrial permeability transition pore (mPTP), the mitochondrial membrane potential (MMP), and ATP were detected. The reactive oxygen species (ROS) content and the NAD+/NADH ratio were determined. The glutamate (Glu) and glutamine (Gln) contents as well as the Ca2+ concentration were determined. The expression of PKCε, p-PKCε, namely, Sirt5, GLS, Drp1, p-Drp1 616, Fis1, Opa1, and Mfn2 was determined via Western blotting. Immunohistochemistry was used to detect p-PKCε, which is expressed at high levels. Immunofluorescence was used to detect p-Drp1 616, Opa1 and Sirt5 fluorescence intensity. ResultsBYHWD treatment enhanced neurological function, decreased the amount of CI, mitigated neuronal damage, decreased mPTP opening, restored the MMP, increased ATP synthesis, and decreased the ROS content after brain I/R. It also increased PKCε, p-PKCε, Sirt5, GLS, Opa1 and Mfn2 expression; downregulated p-Drp1 616, Drp1 and Fis1 expression; elevated the NAD+/NADH ratio and Gln content; and decreased the Glu content and Ca2+ concentration. The effects of BYHWD were reversed by the administration of the PKCε inhibitor εV1-2. BYHWD administration led to increased PKCε mRNA expression. ConclusionsBYHWD modulates MD by diminishing calcium overload through the PKCε-Nampt-Sirt5 axis, which restores mitochondrial function and mitigates brain I/R damage.

Trimetazidine attenuates Ischemia/Reperfusion-Induced myocardial ferroptosis by modulating the Sirt3/Nrf2-GSH system and reducing Oxidative/Nitrative stress

Ferroptosis is a newly defined mode of cellular demise. The increasing investigation supports that ferroptosis is a crucial factor in the complex mechanisms of myocardial ischemia–reperfusion (I/R) injury. Hence, targeting ferroptosis is a novel strategy for treating myocardial injury. Although evidence suggests that trimetazidine (TMZ) is potentially efficacious against myocardial injury, the exact mechanism of this efficacy is yet to be fully elucidated. This study aimed to determine whether TMZ can act as a ferroptosis resistor and affect I/R-mediated myocardial injury. To this end, researchers have constructed in vitro and in vivo models of I/R using H9C2 cardiomyocytes, primary cardiomyocytes, and SD rats. Here, I/R mediated the onset of ferroptosis in vitro and in vivo, as reflected by excessive iron aggregation, GSH depletion, and the increase in lipid peroxidation. TMZ largely reversed this alteration and attenuated cardiomyocyte injury. Mechanistically, we found that TMZ upregulated the expression of Sirt3. Therefore, we used si-Sirt3 and 3-TYP to interfere with Sirt3 action in vitro and in vivo, respectively. Both si-Sirt3 and 3-TYP partly mitigated the inhibitory effect of TMZ on I/R-mediated ferroptosis and upregulated the expression of Nrf2 and its downstream target, GPX4-SLC7A11. These results indicate that TMZ attenuates I/R-mediated ferroptosis by activating the Sirt3-Nrf2/GPX4/SLC7A11 signaling pathway. Our study offers insights into the mechanism underlying the cardioprotective benefits of TMZ and establishes a groundwork for expanding its potential applications.

Lactucin ameliorates FFA-induced steatosis in HepG2 cells by modulating mitochondrial homeostasis through the SIRT1/PGC-1α signaling axis

Nonalcoholic fatty liver disease is a complex disease involving abnormal liver metabolism. Its strong association with metabolic dysfunction has led to a change in nomenclature to metabolism dysfunction-associated fatty liver disease (MAFLD). MAFLD pathogenesis involves abnormal accumulation of hepatic lipids that lead to the production of excess free fatty acids (FFAs), which in turn cause an imbalance in hepatic mitochondrial function. Lactucin, a natural compound extracted from Cichorium glandulosum Boiss. et Huet, regulates liver metabolism and protects the liver. However, the potential mechanisms underlying the lactucin-mediated effects in MAFLD require further investigation. In the present study, HepG2 cells were treated with FFAs to establish an in vitro model of MAFLD. Parameters related to lipid accumulation and mitochondrial function, including triglycerides (TG), oil red O-stained lipid droplets, reactive oxygen species (ROS), mitochondrial membrane potential (JC-1), adenine triphosphate (ATP), and complex III were analysed. Morphology of the mitochondria were evaluated by transmission electron microscopy. Furthermore, key proteins in the sirtuin 1 (SIRT1)/peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α) signalling axis and mitochondrial quality control were analysed. The SIRT1 inhibitor EX-527 was used to verify the key role of the SIRT1 signalling pathway. Western blotting showed that lactucin upregulated the expression of SIRT-1, PGC-1α, Nrf1, Tfam, Mfn2, and Opa1, and promoted mitochondrial biosynthesis and kinetics. The results suggest that lactucin restores mitochondrial dynamic homeostasis by upregulating the SIRT1/PGC-1α signalling axis, thereby reducing FFA-induced lipid accumulation in HepG2 cells.

Bioactive fraction of Musa balbisiana seed mitigates D-galactose-induced brain aging via SIRT1/PGC-1α/FoxO3a activation and intestinal barrier dysfunction by modulating gut microbiota and core metabolites

Aging is an inevitable biological process, and emerging research has highlighted the potential of dietary and pharmacological interventions to decelerate the trajectory of age-related diseases and prolong the health span. This study evaluates the protective effects of Musa balbisiana seed on healthy aging using D-galactose-induced accelerated aging rats. The results suggested that the bioactive ethyl acetate fraction of Musa balbisiana seed extract (BF) exhibited protective effects against aging-induced oxidative stress by reducing oxidative DNA damage, advanced glycation end-product formation, and malondialdehyde levels while restoring antioxidant and glyoxalase enzyme activities. BF also ameliorated neurodegeneration by decreasing acetylcholinesterase enzyme activity and amyloid beta plaque formation. Histopathological analysis demonstrated the protective effects of BF against brain aging, liver disruption, renal damage, and intestinal barrier dysfunction. BF further restored intestinal permeability by upregulating the tight junctions (zonula occludens 1 and 2, claudin 1,2,3 and 4, and occludin) and mucin (mucin 2 and mucin 5ac) gene expression while downregulating the expression of inflammatory cytokines (IL-1β, IL-6, and TNF-α). BF significantly induced the phosphorylation of FoxO3a proteins and upregulated the gene expression of SIRT1, PGC-1α, and TFAM in the hippocampus. Next-generation sequencing (NGS) of 16s rRNA amplicons of fecal metagenomics DNA and metabolites profiling showed that BF intervention restructured the gut microbiota and altered core metabolites related to cholesterol metabolism. Overall, our findings demonstrated the multifaceted protective effects of Musa balbisiana seed against D-galactose-induced aging.

Panax notoginseng saponins improves lipid metabolism and prevents atherosclerosis in mice with steroid-resistant lupus nephritis via the SIRT1/PPARγ signaling pathway

Steroids serve as the primary medication for treating lupus nephritis (LN), however, steroid-resistance (SR) occurs sporadically in clinical practice, significantly affecting the therapeutic effect and long-term prognosis of patients. Our previous study found that panax notoginseng saponins (PNS) could partially reverse SR in LN. To further explore the role of PNS in reversing SR and reducing cardiovascular complications in LN, we conducted this study. Lupus mice were induced into SR while simultaneously receiving PNS. SIRT1-siRNA, SIRT1-siRNA NC, normal and lupus mice were used as control groups. Urine protein levels were measured at week 0, 4 and 8. Lipid metabolism-related biomarkers and renal function were assessed. The apoptosis rate of abdominal aortic endothelial cells was detected using flow-cytometry. The expression levels of PPARγ and SIRT1 were measured using RT-PCR and Western Blotting. Immunohistochemistry was performed to examine ACAT1 and VCAM-1 expressions. The results showed that compared to the SR lupus mice, the lupus mice treated with low/high dose PNS presented lower levels of urinary protein, serum creatinine, and blood lipids, a lower apoptosis rate of abdominal aortic endothelial cells, and decreased levels of ACAT1 and VCAM-1 PI in liver tissue, while the high-dose PNS exhibited more evidently. The PPARγ expression in SIRT1-siRNA group, as well as in low-dose and high-dose PNS groups was higher than that in the lupus and SR lupus group. In contrast, the expression of SIRT1 showed the opposite trend. Therefore, we conclude that PNS has the efficacy of reversing SR and ameliorating dyslipidemia in LN by modulating the SIRT1/PPARγ signaling pathway.

Artemisia capillaris Thunb. Water Extract Alleviates Metabolic Dysfunction-associated Steatotic Liver Disease Disease by Inhibiting miR-34a-5p to Activate Sirt1-mediated Hepatic Lipid Metabolism

Artemisia capillaris Thunb. (ACT) is a plant in the Asteraceae family. Its traditional effects are to clear away dampness and heat, promote gallbladder and reduce jaundice. Traditional Chinese medicine believes that MASLD is a damp-heat syndrome. The group's previous study showed that Artemisia capillaris Thunb. Water Extract (ACTE) has an improved effect on MASLD. In order to further understand its mechanism of action, this study established a mouse MASLD model and a HepG2 cell lipid droplet model, combined small RNA sequencing and miRNA transfection experiments, to explore the mechanism of ACTE to improve MASLD by modulating miRNA-targeted mRNA. Non-targeted metabolomics method was used to detect and analyze ACTE. This study screened miR-34a-5p and confirmed its target mRNA-Sirtuin 1 (Sirt1). MASLD induced high expression of miR-34a-5p and low expression of Sirt1, and ACE reversed these changes. When overexpressing miR-34a-5p or knocking down Sirt1, the effect of ACE in reducing PO (palmitic acid and oleic acid complex)-induced lipid accumulation in HepG2 cells was attenuated. ACTE reduces the expression of FASN, SCD1, ACC, and SREBP-1c, promotes the expression of CPT-1 and HSL, thereby reducing lipid accumulation. ACTE activates Sirt1 by inhibiting the expression of miR-34a-5p, thereby reducing liver lipid accumulation and improving HFD-induced MASLD. These findings highlight the potential of ACTE in reducing weight, controlling obesity, and improving lipid metabolism disorders.