N-acetyltransferase 10 facilitates tumorigenesis of diffuse large B-cell lymphoma by regulating AMPK/mTOR signalling through N4-acetylcytidine modification of SLC30A9.

BACKGROUND: Accumulating studies suggested that posttranscriptional modifications exert a vital role in the tumorigenesis of diffuse large B-cell lymphoma (DLBCL). N4-acetylcytidine (ac4C) modification, catalyzed by the N-acetyltransferase 10 (NAT10), was a novel type of chemical modification that improves translation efficiency and mRNA stability. METHODS: GEO databases and clinical samples were used to explore the expression and clinical value of NAT10 in DLBCL. CRISPER/Cas9-mediated knockout of NAT10 was performed to determine the biological functions of NAT10 in DLBCL. RNA sequencing, acetylated RNA immunoprecipitation sequencing (acRIP-seq), LC-MS/MS, RNA immunoprecipitation (RIP)-qPCR and RNA stability assays were performed to explore the mechanism by which NAT10 contributed to DLBCL progression. RESULTS: Here, we demonstrated that NAT10-mediated ac4C modification regulated the occurrence and progression of DLBCL. Dysregulated N-acetyltransferases expression was found in DLBCL samples. High expression of NAT10 was associated with poor prognosis of DLBCL patients. Deletion of NAT10 expression inhibited cell proliferation and induced G0/G1 phase arrest. Furthermore, knockout of NAT10 increased the sensitivity of DLBCL cells to ibrutinib. AcRIP-seq identified solute carrier family 30 member 9 (SLC30A9) as a downstream target of NAT10 in DLBCL. NAT10 regulated the mRNA stability of SLC30A9 in an ac4C-dependent manner. Genetic silencing of SLC30A9 suppressed DLBCL cell growth via regulating the activation of AMP-activated protein kinase (AMPK) pathway. CONCLUSION: Collectively, these findings highlighted the essential role of ac4C RNA modification mediated by NAT10 in DLBCL, and provided insights into novel epigenetic-based therapeutic strategies.

Amelioration of Oxidative Stress in Rats with Chronic Obstructive Pulmonary Disease through Shenqi Huatan Decoction Activation of Peroxisome Proliferator-Activated Receptor Gamma-Mediated Activated Protein Kinase/Forkhead Transcription Factor O3a Signaling Pathway.

Background: Chronic obstructive pulmonary disease (COPD) is a common respiratory disease. Currently, no specific treatment strategy has been established; therefore, finding new treatment methods is essential. Clinically, Shenqi Huatan Decoction (SQHT) is a traditional Chinese medicinal formula for COPD treatment; however, its mechanism of action in treatment needs to be clarified. Methods: The COPD rat model was replicated by cigarette smoking and tracheal injection using the LPS method. The control group and the SQHT groups were treated with dexamethasone and SQHT by gavage, respectively. After treatment, superoxide dismutase (SOD) serum levels, total antioxidant capacity (TAOC), lipid peroxidation, and malondialdehyde (MDA) were detected by enzyme-linked immunosorbent assay (ELISA). Activated protein kinase alpha (AMPK-α), forkhead transcription factor O3a (FOXO3a), manganese SOD (MnSOD), and peroxisome proliferator-activated receptor gamma (PPARγ) were detected using reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) and Western blot. Microribonucleic acid and protein expression levels were measured, and pathological changes in lung tissue were observed using hematoxylin and eosin staining. Results: The pathological findings suggested that SQHT substantially affects COPD treatment by enhancing alveolar fusion and reducing emphysema. ELISA results showed that SQHT could lower the blood levels of MDA and lipid peroxide and raise SOD and TAOC levels, suggesting that it could lessen oxidative stress. In the lung tissue of rats with COPD, large doses of SQHT intervention dramatically increased AMPK protein expression, AMPK-α, FOXO3a, MnSOD, and PPARγ, indicating that SQHT may reduce oxidative stress by activating the PPARγ-mediated AMPK/FOXO3a signaling pathway. Similar results were obtained using RT-qPCR. Conclusion: SQHT is effective for COPD treatment. The mechanism of action may be related to the activation of the PPARγ-mediated AMPK/FOXO3a signaling pathway to improve oxidative stress in lung tissue.

Kaempferia parviflora extract and its component polymethoxyflavones suppress adipogenic differentiation of human bone marrow-derived mesenchymal stem cells via the AMPK pathway.

BACKGROUND: Kaempferia parviflora Wall. ex. Baker (KP) has been reported to exhibit anti-obesity effects. However, the detailed mechanism of the anti-obesity effect of KP extract (KPE) is yet to be clarified. Here, we investigated the effect of KPE and its component polymethoxyflavones (PMFs) on the adipogenic differentiation of human mesenchymal stem cells (MSCs). METHODS AND RESULTS: KPE and PMFs fraction (2.5 µg/mL) significantly inhibited lipid and triacylglyceride accumulation in MSCs; lipid accumulation in MSCs was suppressed during the early stages of differentiation (days 0-3) but not during the mid (days 3-7) or late (days 7-14) stages. Treatment with KPE and PMFs fractions significantly suppressed peroxisome proliferator-activated receptor-γ (PPARγ), CCAAT/enhancer binding protein α (C/EBPα), and various adipogenic metabolic factors. Treatment with KPE and PMFs fraction induced the activation of AMP-activated protein kinase (AMPK) signaling, and pretreatment with an AMPK signaling inhibitor significantly attenuated KPE- and PMFs fraction-induced suppression of lipid formation. CONCLUSIONS: Our findings demonstrate that KPE and PMFs fraction inhibit lipid formation by inhibiting the differentiation of undifferentiated MSCs into adipocyte lineages via AMPK signaling, and this may be the mechanism underlying the anti-obesity effects of KPE and PMFs. Our study lays the foundation for the elucidation of the anti-obesity mechanism of KPE and PMFs.

BRD7 facilitates ferroptosis via modulating clusterin promoter hypermethylation and suppressing AMPK signaling in diabetes-induced testicular damage.

BACKGROUND: Diabetes mellitus (DM)-induced testicular damage is associated with sexual dysfunction and male infertility in DM patients. However, the pathogenesis of DM-induced testicular damage remains largely undefined. METHODS: A streptozotocin (STZ)-induced diabetic model and high glucose (HG)-treated in vitro diabetic model were established. The histological changes of testes were assessed by H&E staining. Serum testosterone, iron, MDA and GSH levels were detected using commercial kits. Cell viability and lipid peroxidation was monitored by MTT assay and BODIPY 581/591 C11 staining, respectively. qRT-PCR, immunohistochemistry (IHC) or Western blotting were employed to detect the levels of BRD7, Clusterin, EZH2 and AMPK signaling molecules. The associations among BRD7, EZH2 and DNMT3a were detected by co-IP, and the transcriptional regulation of Clusterin was monitored by methylation-specific PCR (MSP) and ChIP assay. RESULTS: Ferroptosis was associated with DM-induced testicular damage in STZ mice and HG-treated GC-1spg cells, and this was accompanied with the upregulation of BRD7. Knockdown of BRD7 suppressed HG-induced ferroptosis, as well as HG-induced Clusterin promoter methylation and HG-inactivated AMPK signaling in GC-1spg cells. Mechanistical studies revealed that BRD7 directly bound to EZH2 and regulated Clusterin promoter methylation via recruiting DNMT3a. Knockdown of Clusterin or inactivation of AMPK signaling reverses BRD7 silencing-suppressed ferroptosis in GC-1spg cells. In vivo findings showed that lack of BRD7 protected against diabetes-induced testicular damage and ferroptosis via increasing Clusterin expression and activating AMPK signaling. CONCLUSION: BRD7 suppressed Clusterin expression via modulating Clusterin promoter hypermethylation in an EZH2 dependent manner, thereby suppressing AMPK signaling to facilitate ferroptosis and induce diabetes-associated testicular damage.

Role of AMPK-regulated autophagy in retinal pigment epithelial cell homeostasis: A review.

The retinal pigment epithelium (RPE) is a regularly arranged monolayer of cells in the outermost layer of the retina. It is crucial for transporting nutrients and metabolic substances in the retina and maintaining the retinal barrier. RPE dysfunction causes diseases related to vision loss. Thus, understanding the mechanisms involved in normal RPE function is vital. Adenosine monophosphate-activated protein kinase (AMPK) is an RPE energy sensor regulating various signaling and metabolic pathways to maintain cellular energetic homeostasis. AMPK activation is involved in multiple signaling pathways regulated by autophagy in the RPE, thereby protecting the cells from oxidative stress and slowing RPE degeneration. In this review, we attempt to broaden the understanding of the pathogenesis of RPE dysfunction by focusing on the role and mechanism of AMPK regulation of autophagy in the RPE. The correlation between RPE cellular homeostasis and role of AMPK was determined by analyzing the structure and mechanism of AMPK and its signaling pathway in autophagy. The protective effect of AMPK-regulated autophagy on the RPE for gaining insights into the regulatory pathways of RPE dysfunction has been discussed.

Cancer EV stimulate endothelial glycolysis to fuel protein synthesis via mTOR and AMPKα activation.

Hypoxia is a common feature of solid tumours and activates adaptation mechanisms in cancer cells that induce therapy resistance and has profound effects on cellular metabolism. As such, hypoxia is an important contributor to cancer progression and is associated with a poor prognosis. Metabolic alterations in cells within the tumour microenvironment support tumour growth via, amongst others, the suppression of immune reactions and the induction of angiogenesis. Recently, extracellular vesicles (EV) have emerged as important mediators of intercellular communication in support of cancer progression. Previously, we demonstrated the pro-angiogenic properties of hypoxic cancer cell derived EV. In this study, we investigate how (hypoxic) cancer cell derived EV mediate their effects. We demonstrate that cancer derived EV regulate cellular metabolism and protein synthesis in acceptor cells through increased activation of mTOR and AMPKα. Using metabolic tracer experiments, we demonstrate that EV stimulate glucose uptake in endothelial cells to fuel amino acid synthesis and stimulate amino acid uptake to increase protein synthesis. Despite alterations in cargo, we show that the effect of cancer derived EV on recipient cells is primarily determined by the EV producing cancer cell type rather than its oxygenation status.

Effects of kaempherol-3-rhamnoside on metabolic enzymes and AMPK in the liver tissue of STZ-induced diabetes in mice.

Diabetes mellitus (DM) is a chronic metabolic disorder characterized by persistent hyperglycemia. It involves disturbances in carbohydrate, fat, and protein metabolism due to defects in insulin secretion, insulin action, or both. Novel therapeutic approaches are continuously being explored to enhance metabolic control and prevent complications associated with the disease. This study investigates the therapeutic potential of kaempherol-3-rhamnoside, a flavonoid, in managing diabetes by modulating the AMP-activated protein kinase (AMPK) pathway and improving metabolic enzyme activities in streptozotocin (STZ) -induced diabetic mice. Diabetic mice were treated with varying doses of kaempherol-3-rhamnoside and/or insulin over a 28-day period. Glycolytic and gluconeogenesis enzyme activities in the liver, fasting blood glucose levels, serum insulin levels, lipid profiles and oxidative stress markers were assessed. Treatment with kaempherol-3-rhamnoside significantly improved glycolytic enzyme activities, reduced fasting blood glucose, and enhanced insulin levels compared to diabetic controls. The compound also normalized lipid profiles and reduced oxidative stress in the liver, suggesting its potential in reversing diabetic dyslipidemia and oxidative damage. Furthermore, kaempherol-3-rhamnoside activated the AMPK pathway, indicating a mechanism through which it could exert its effects. Kaempherol-3-rhamnoside exhibits promising antidiabetic properties, potentially through AMPK pathway activation and metabolic enzyme modulation. These findings support its potential use as an adjunct therapy for diabetes management. Further clinical studies are warranted to validate these results in human subjects.

Glucose-6-phosphate dehydrogenase maintains redox homeostasis and biosynthesis in LKB1-deficient KRAS-driven lung cancer.

Cancer cells depend on nicotinamide adenine dinucleotide phosphate (NADPH) to combat oxidative stress and support reductive biosynthesis. One major NADPH production route is the oxidative pentose phosphate pathway (committed step: glucose-6-phosphate dehydrogenase, G6PD). Alternatives exist and can compensate in some tumors. Here, using genetically-engineered lung cancer mouse models, we show that G6PD ablation significantly suppresses KrasG12D/+;Lkb1-/- (KL) but not KrasG12D/+;P53-/- (KP) lung tumorigenesis. In vivo isotope tracing and metabolomics reveal that G6PD ablation significantly impairs NADPH generation, redox balance, and de novo lipogenesis in KL but not KP lung tumors. Mechanistically, in KL tumors, G6PD ablation activates p53, suppressing tumor growth. As tumors progress, G6PD-deficient KL tumors increase an alternative NADPH source from serine-driven one carbon metabolism, rendering associated tumor-derived cell lines sensitive to serine/glycine depletion. Thus, oncogenic driver mutations determine lung cancer dependence on G6PD, whose targeting is a potential therapeutic strategy for tumors harboring KRAS and LKB1 co-mutations.

Iron Regulates Cellular Proliferation by Enhancing the Expression of Glucose Transporter GLUT3 in the Liver.

Iron is often accumulated in the liver during pathological conditions such as cirrhosis and cancer. Elevated expression of glucose transporters GLUT1 and GLUT3 is associated with reduced overall survival in patients with hepatocellular carcinoma. However, it is not known whether iron can regulate glucose transporters and contribute to tumor proliferation. In the present study, we found that treatment of human liver cell line HepG2 with ferric ammonium citrate (FAC) resulted in a significant upregulation of GLUT3 mRNA and protein in a dose-dependent manner. Similarly, iron accumulation in mice fed with high dietary iron as well as in mice injected intraperitoneally with iron dextran enhanced the GLUT3 expression drastically in the liver. We demonstrated that iron-induced hepatic GLUT3 upregulation is mediated by the LKB1/AMPK/CREB1 pathway, and this activation was reversed when treated with iron chelator deferiprone. In addition, inhibition of GLUT3 using siRNA prevented iron-mediated increase in the expression of cell cycle markers and cellular hyperproliferation. Furthermore, exogenous sodium beta-hydroxybutyrate treatment prevented iron-mediated hepatic GLUT3 activation both in vitro and in vivo. Together, these results underscore the importance of iron, AMPK, CREB1 and GLUT3 pathways in cell proliferation and highlight the therapeutic potential of sodium beta-hydroxybutyrate in hepatocellular carcinoma with high GLUT3 expression.

Salusin­α alleviates lipid metabolism disorders via regulation of the downstream lipogenesis genes through the LKB1/AMPK pathway.

Lipid metabolism disorders are a major cause of several chronic metabolic diseases which seriously affect public health. Salusin­α, a vasoactive peptide, has been shown to attenuate lipid metabolism disorders, although its mechanism of action has not been reported. To investigate the effects and potential mechanisms of Salusin­α on lipid metabolism, Salusin­α was overexpressed or knocked down using lentiviral vectors. Hepatocyte steatosis was induced by free fatty acid (FFA) after lentiviral transfection into HepG2 cells. The degree of lipid accumulation was assessed using Oil Red O staining and by measuring several biochemical indices. Subsequently, bioinformatics was used to analyze the signaling pathways that may have been involved in lipid metabolism disorders. Finally, semi­quantitative PCR and western blotting were used to verify the involvement of the liver kinase B1 (LKB1)/AMPK pathway. Compound C, an inhibitor of AMPK, was used to confirm this mechanism's involvement further. The results showed that Salusin­α significantly attenuated lipid accumulation, inflammation and oxidative stress. In addition, Salusin­α increased the levels of LKB1 and AMPK, which inhibited the expression of sterol regulatory element binding protein­1c, fatty acid synthase and acetyl­CoA carboxylase. The addition of Compound C abrogated the Salusin­α­mediated regulation of AMPK on downstream signaling molecules. In summary, overexpression of Salusin­α activated the LKB1/AMPK pathway, which in turn inhibited lipid accumulation in HepG2 cells. This provides insights into the potential mechanism underlying the mechanism by which Salusin­α ameliorates lipid metabolism disorders while identifying a potential therapeutic target.

The role of quercetin in ameliorating bleomycin-induced pulmonary fibrosis: insights into autophagy and the SIRT1/AMPK signaling pathway.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a disease of unknown etiology characterized by a constant incidence rate. Unfortunately, effective pharmacological treatments for this condition are lacking and the identification of novel therapeutic approaches and underlying pathological mechanisms are required. This study investigated the potential of quercetin in alleviating pulmonary fibrosis by promoting autophagy and activation of the SIRT1/AMPK pathway. METHODS: Mouse models of IPF were divided into four treatment groups: control, bleomycin (BLM), quercetin (Q), and quercetin + EX-527 (Q + E) treatment. Pulmonary fibrosis was induced in the mouse models through intratracheal instillation of BLM. Various indexes were identified through histological staining, Western blotting analysis, enzyme-linked immunosorbent assay, immunohistochemistry, and transmission electron microscopy. RESULTS: Quercetin treatment ameliorated the pathology of BLM-induced pulmonary fibrosis of mice by reducing α-smooth muscle actin (α-SMA), collagen I (Col I), and collagen III (Col III) levels, and also improved the level of E-cadherin in lung tissue. Furthermore, Quercetin significantly enhanced LC3II/LC3I levels, decreased P62 expression, and increased the number of autophagosomes in lung tissue. These effects were accompanied by the activation of the SIRT1/AMPK pathway. Treatment with EX-527, an inhibitor for SIRT1, reversed all effects induced by quercetin. CONCLUSION: This study showed that quercetin could alleviate pulmonary fibrosis and improve epithelial-mesenchymal transition by acting on the SIRT1/AMPK signaling pathway, which may be achieved by regulating the level of autophagy.

BNIP3-mediated mitophagy boosts the competitive growth of Lenvatinib-resistant cells via energy metabolism reprogramming in HCC.

An increasing evidence supports that cell competition, a vital selection and quality control mechanism in multicellular organisms, is involved in tumorigenesis and development; however, the mechanistic contributions to the association between cell competition and tumor drug resistance remain ill-defined. In our study, based on a contructed lenvitinib-resistant hepatocellular carcinoma (HCC) cells display obvious competitive growth dominance over sensitive cells through reprogramming energy metabolism. Mechanistically, the hyperactivation of BCL2 interacting protein3 (BNIP3) -mediated mitophagy in lenvatinib-resistant HCC cells promotes glycolytic flux via shifting energy production from mitochondrial oxidative phosphorylation to glycolysis, by regulating AMP-activated protein kinase (AMPK) -enolase 2 (ENO2) signaling, which perpetually maintaining lenvatinib-resistant HCC cells' competitive advantage over sensitive HCC cells. Of note, BNIP3 inhibition significantly sensitized the anti-tumor efficacy of lenvatinib in HCC. Our findings emphasize a vital role for BNIP3-AMPK-ENO2 signaling in maintaining the competitive outcome of lenvitinib-resistant HCC cells via regulating energy metabolism reprogramming; meanwhile, this work recognizes BNIP3 as a promising target to overcome HCC drug resistance.

Salicylate induces epithelial actin reorganization via activation of the AMP-activated protein kinase and promotes wound healing and contraction in mice.

Wounds that occur in adults form scars due to fibrosis, whereas those in embryos regenerate. If wound healing in embryos is mimicked in adults, scarring can be reduced. We found that mouse fetuses could regenerate tissues up to embryonic day (E) 13, but visible scars remained thereafter. This regeneration pattern requires actin cable formation at the epithelial wound margin via activation of adenosine monophosphate (AMP)-activated protein kinase (AMPK). Here, we investigated whether the AMPK-activating effect of salicylate, an anti-inflammatory drug, promotes regenerative wound healing. Salicylate administration resulted in actin cable formation and complete wound regeneration in E14 fetuses, in which scarring should have normally occurred, and promoted contraction of the panniculus carnosus muscle, resulting in complete wound regeneration. In vitro, salicylate further induced actin remodeling in mouse epidermal keratinocytes in a manner dependent on cell and substrate target-specific AMPK activation and subsequent regulation of Rac1 signaling. Furthermore, salicylate promoted epithelialization, enhanced panniculus carnosus muscle contraction, and inhibited scar formation in adult mice. Administration of salicylates to wounds immediately after injury may be a novel method for preventing scarring by promoting a wound healing pattern similar to that of embryonic wounds.

The SIRT2-AMPK axis regulates autophagy induced by acute liver failure.

This study explores the role of SIRT2 in regulating autophagy and its interaction with AMPK in the context of acute liver failure (ALF). This study investigated the effects of SIRT2 and AMPK on autophagy in ALF mice and TAA-induced AML12 cells. The results revealed that the liver tissue in ALF model group had a lot of inflammatory cell infiltration and hepatocytes necrosis, which were reduced by SIRT2 inhibitor AGK2. In comparison to normal group, the level of SIRT2, P62, MDA, TOS in TAA group were significantly increased, which were decreased in AGK2 treatment. Compared with normal group, the expression of P-PRKAA1, Becilin1 and LC3B-II was decreased in TAA group. However, AGK2 enhanced the expression of P-PRKAA1, Becilin1 and LC3B-II in model group. Overexpression of SIRT2 in AML12 cell resulted in decreased P-PRKAA1, Becilin1 and LC3B-II level, enhanced the level of SIRT2, P62, MDA, TOS. Overexpression of PRKAA1 in AML12 cell resulted in decreased SIRT2, TOS and MDA level and triggered more autophagy. In conclusion, the data suggested the link between AMPK and SIRT2, and reveals the important role of AMPK and SIRT2 in autophagy on acute liver failure.

Far-infrared therapy promotes exercise capacity and glucose metabolism in mice by modulating microbiota homeostasis and activating AMPK.

The benefits of physical exercise on human health make it desirable to identify new approaches that would mimic or potentiate the effects of exercise to treat metabolic diseases. However, whether far-infrared (FIR) hyperthermia therapy could be used as exercise mimetic to realize wide-ranging metabolic regulation, and its underling mechanisms remain unclear. Here, a specific far-infrared (FIR) rays generated from graphene-based hyperthermia devices might promote exercise capacity and metabolisms. The material characterization showed that the graphene synthesized by chemical vapour deposition (CVD) was different from carbon fiber, with single-layer structure and high electrothermal transform efficiency. The emission spectra generated by graphene-FIR device would maximize matching those adsorbed by tissues. Graphene-FIR enhanced both core and epidermal temperatures, leading to increased blood flow in the femoral muscle and the abdominal region. The combination of microbiomic and metabolomic analysis revealed that graphene-FIR modulates the metabolism of the gut-muscle axis. This modulation was characterized by an increased abundance of short-chain fatty acids (SCFA)-producing bacteria and AMP, while lactic acid levels decreased. Furthermore, the principal routes involved in glucose metabolism, such as glycolysis and gluconeogenesis, were found to be altered. Graphene-FIR managed to stimulate AMPK activity by activating GPR43, thus enhancing muscle glucose uptake. Furthermore, a microbiota disorder model also demonstrated that the graphene-FIR effectively restore the exercise endurance with enhanced p-AMPK and GLUT4. Our results provided convincing evidence that graphene-based FIR therapy promoted exercise capacity and glucose metabolism via AMPK in gut-muscle axis. These novel findings regarding the therapeutic effects of graphene-FIR suggested its potential utility as a mimetic agent in clinical management of metabolic disorders.

Glucosyltriazole amphiphile treatment attenuates breast cancer by modulating the AMPK signaling.

Breast cancer is the second most frequent cancer among women. Out of various subtypes, triple-negative breast cancers (TNBCs) account for 15% of breast cancers and exhibit more aggressive characteristics as well as a worse prognosis due to their proclivity for metastatic progression and limited therapeutic strategies. It has been demonstrated that AMP-activated protein kinase (AMPK) has context-specific protumorigenic implications in breast cancer cells. A set of glucosyltriazole amphiphiles, consisting of acetylated (9a-h) and unmodified sugar hydroxyl groups (10a-h), were synthesized and subjected to in vitro biological evaluation. Among them, 9h exhibited significant anticancer activity against MDA-MB-231, MCF-7, and 4T1 cell lines with IC50 values of 12.5, 15, and 12.55 µM, respectively. Further, compound 9h was evaluated for apoptosis and cell cycle analysis in in vitro models (using breast cancer cells) and antitumour activity in an in vivo model (orthotopic mouse model using 4T1 cells). Annexin-V assay results revealed that treatment with 9h caused 34% and 28% cell death at a concentration of 15 or 7.5 µM, respectively, while cell cycle analysis demonstrated that 9h arrested the cells at the G2/M or G1 phase in MCF-7, MDA-MB-231 and 4T1 cells, respectively. Further, in vivo, investigation showed that compound 9h exhibited equipotent as doxorubicin at 7.5 mg/kg, and superior efficacy than doxorubicin at 15 mg/kg. The mechanistic approach revealed that 9h showed potent anticancer activity in an in vivo orthotopic model (4T1 cells) partly by suppressing the AMPK activation. Therefore, modulating the AMPK activation could be a probable approach for targeting breast cancer and mitigating cancer progression.

Exogenous Nucleotides Improve the Skin Aging of SAMP8 Mice by Modulating Autophagy through MAPKs and AMPK Pathways.

The skin, serving as the body's primary defense against external elements, plays a crucial role in protecting the body from infections and injuries, as well as maintaining overall homeostasis. Skin aging, a common manifestation of the aging process, involves the gradual deterioration of its normal structure and repair mechanisms. Addressing the issue of skin aging is increasingly imperative. Multiple pieces of evidence indicate the potential anti-aging effects of exogenous nucleotides (NTs) through their ability to inhibit oxidative stress and inflammation. This study aims to investigate whether exogenous NTs can slow down skin aging and elucidate the underlying mechanisms. To achieve this objective, senescence-accelerated mouse prone-8 (SAMP8) mice were utilized and randomly allocated into Aging, NTs-low, NTs-middle, and NTs-high groups, while senescence-accelerated mouse resistant 1 (SAMR1) mice were employed as the control group. After 9 months of NT intervention, dorsal skin samples were collected to analyze the pathology and assess the presence and expression of substances related to the aging process. The findings indicated that a high-dose NT treatment led to a significant increase in the thickness of the epithelium and dermal layers, as well as Hyp content (p < 0.05). Additionally, it was observed that low-dose NT intervention resulted in improved aging, as evidenced by a significant decrease in p16 expression (p < 0.05). Importantly, the administration of high doses of NTs could improve, in some ways, mitochondrial function, which is known to reduce oxidative stress and promote ATP and NAD+ production significantly. These observed effects may be linked to NT-induced autophagy, as evidenced by the decreased expression of p62 and increased expression of LC3BI/II in the intervention groups. Furthermore, NTs were found to upregulate pAMPK and PGC-1α expression while inhibiting the phosphorylation of p38MAPK, JNK, and ERK, suggesting that autophagy may be regulated through the AMPK and MAPK pathways. Therefore, the potential induction of autophagy by NTs may offer benefits in addressing skin aging through the activation of the AMPK pathway and the inhibition of the MAPK pathway.

Bioactive Peptides from Meretrix lusoria Enzymatic Hydrolysate as a Potential Treatment for Obesity in db/db Mice.

Obesity is acknowledged as a significant risk factor for cardiovascular disease, often accompanied by increased inflammation and diabetes. Bioactive peptides derived from marine animal proteins show promise as safe and effective anti-obesity agents by regulating adipocyte differentiation through the AMPK signaling pathway. Therefore, this study aims to investigate the anti-obesity and anti-diabetic effects of bioactive compounds derived from a Meretrix lusoria Protamex enzymatic hydrolysate (MLP) fraction (≤1 kDa) through a 6-week treatment (150 mg/kg or 300 mg/kg, administered once daily) in leptin receptor-deficient db/db mice. The MLP treatment significantly decreased the body weight, serum total cholesterol, triglycerides, and LDL-cholesterol levels while also exhibiting a beneficial effect on hepatic and serum marker parameters in db/db mice. A histological analysis revealed a reduction in hepatic steatosis and epididymal fat following MLP treatment. Furthermore, poor glucose tolerance was improved, and hepatic antioxidant enzyme activities were elevated in MLP-treated mice compared to db/db control mice. Western blot analysis showed an increased expression of the AMPK protein after MLP treatment. In addition, the expression of lipogenic genes decreased in db/db mice. These findings indicate that bioactive peptides, which are known to regulate blood glucose levels, lipid metabolism, and adipogenesis, could be beneficial functional food additives and pharmaceuticals.

AdipoRon, an adiponectin receptor agonist, modulates AMPK signaling pathway and alleviates ovalbumin-induced airway inflammation in a murine model of asthma.

Asthma is a long-term disease that causes airways swelling and inflammation and in turn airway narrowing. AdipoRonis an orally active synthetic small molecule that acts as a selective agonist at theadiponectin receptor 1 and 2. The aim of the current study is to delineate the protective effect and the potential underlying mechanism ofadipoRon inairway inflammationinduced byovalbumin (OVA) in comparison withdexamethasone. Adult maleSwiss Albino micewere sensitized to OVA on days 0 and 7, then challenged with OVA on days 14, 15 and 16. AdipoRon was administered orally for 6 days starting from the 11th day till the 16th and 1 h prior to OVA in the challenge days. Obtained results from asthmatic control group showed a significant decrease in serum adiponectin concentration, an increase in inflammatory cell counts inthe bronchoalveolar lavage fluid(BALF), CD68 protein expression, inflammatory cytokine concentration and oxidative stress as well. Administration of adipoRon enhanced antioxidant mechanisms limiting oxidative stress by significantly increasing reduced glutathione (GSH) pulmonary content, decreasing serum lactate dehydrogenase (LDH) together with malondialdehyde (MDA) significant reduction in lung tissue. In addition, it modulated the levels of serum immunoglobulin E (IgE), pro-inflammatory cytokines tumor necrosis factor (TNF)-α, interleukin (IL)-4, IL-13, nuclear factor kappa B (NF-κB) and the anti-inflammatory one IL-10 improving lung inflammation as revealed by histopathological evaluation. Furthermore, lung tissue expression of nuclear factor erythroid 2-related factor (Nrf2) and 5'AMP-activated protein kinase (AMPK) were significantly increased adipoRon. Notably, results of adipoRon received group were comparable to those of dexamethasone group. In conclusion, our study demonstrates that adipoRon can positively modulate adiponectin expression with activation of AMPK pathway and subsequent improvement in inflammatory and oxidative signaling.

Impaired Cardiac AMPK (5'-Adenosine Monophosphate-Activated Protein Kinase) and Ca2+-Handling, and Action Potential Duration Heterogeneity in Ibrutinib-Induced Ventricular Arrhythmia Vulnerability.

BACKGROUND: We recently demonstrated that acute administration of ibrutinib, a Bruton's tyrosine kinase inhibitor used in chemotherapy for blood malignancies, increases ventricular arrhythmia (VA) vulnerability. A pathway of ibrutinib-induced vulnerability to VA that can be modulated for cardioprotection remains unclear. METHODS AND RESULTS: The effects of ibrutinib on cardiac electrical activity and Ca2+ dynamics were investigated in Langendorff-perfused hearts using optical mapping. We also conducted Western blotting analysis to evaluate the impact of ibrutinib on various regulatory and Ca2+-handling proteins in rat cardiac tissues. Treatment with ibrutinib (10 mg/kg per day) for 4 weeks was associated with an increased VA inducibility (72.2%±6.3% versus 38.9±7.0% in controls, P<0.002) and shorter action potential durations during pacing at various frequencies (P<0.05). Ibrutinib also decreased heart rate thresholds for beat-to-beat duration alternans of the cardiac action potential (P<0.05). Significant changes in myocardial Ca2+ transients included lower amplitude alternans ratios (P<0.05), longer times-to-peak (P<0.05), and greater spontaneous intracellular Ca2+ elevations (P<0.01). We also found lower abundance and phosphorylation of myocardial AMPK (5'-adenosine monophosphate-activated protein kinase), indicating reduced AMPK activity in hearts after ibrutinib treatment. An acute treatment with the AMPK activator 5-aminoimidazole-4-carboxamide-1-ß-D-ribofuranoside ameliorated abnormalities in action potential and Ca2+ dynamics, and significantly reduced VA inducibility (37.1%±13.4% versus 72.2%±6.3% in the absence of 5-aminoimidazole-4-carboxamide-1-ß-D-ribofuranoside, P<0.05) in hearts from ibrutinib-treated rats. CONCLUSIONS: VA vulnerability inflicted by ibrutinib may be mediated in part by an impairment of myocardial AMPK activity. Pharmacological activation of AMPK may be a protective strategy against ibrutinib-induced cardiotoxicity.