AMPK-mTOR Pathway Research Articles

Mangiferin prevents glucolipotoxicity-induced pancreatic beta-cell injury through modulation of autophagy via AMPK-mTOR signaling pathway

The aim of this study was to investigate the protective effects of Mangiferin (MG) on glucolipotoxicity-induced pancreatic beta-cell injury. In vivo administration of MG significantly reduced the level of blood glucose in high-fat diet (HFD)-fed mice. MG treatment inhibited beta-cell apoptosis in HFD-treated mice. In vitro, MG protected INS-1 cells against apoptosis and impairment of insulin secretion following High glucose/Palmitic acid (HG/PA) treatment. MG treatment enhanced autophagy flux which was blocked by HG/PA treatment. Inhibition of autophagosome formation by 3-Methyladenine or blockade of autolysosome by Chloroquine reversed the protective effects of MG on INS-1 cells. MG treatment increased AMPK phosphorylation and reduced mTOR activation in INS-1 cells. Administration of the AMPK blocker abrogated MG-induced autophagy, and similar results were observed in INS-1 cells after cotreatment with MG and mTOR activator. In conclusion, MG ameliorated pancreatic beta-cell injury induced by glucolipotoxicity through modulation of autophagy via the AMPK-mTOR pathway.

Lactate Contributes to Remote Ischemic Preconditioning–Mediated Protection Against Myocardial Ischemia Reperfusion Injury by Facilitating Autophagy via the AMP-Activated Protein Kinase–Mammalian Target of Rapamycin–Transcription Factor EB–Connexin 43 Axis

Remote ischemic preconditioning (RIPC) exerts a protective role on myocardial ischemia reperfusion (I/R) injury by the release of various humoral factors. Lactate is a common metabolite in ischemic tissues. Nevertheless, little is known about the role lactate plays in myocardial I/R injury and its underlying mechanism. This investigation revealed that RIPC elevated the level of lactate in blood and myocardium. Furthermore, AZD3965, a selective monocarboxylate transporter 1 (MCT1) inhibitor and 2-Deoxy-D-glucose (2-DG), a glycolysis inhibitor, mitigated the effects of RIPC-induced elevated lactate in the myocardium and prevented RIPC against myocardial I/R injury. In an in vitro hypoxia reoxygenation (H/R) model, lactate markedly mitigated H/R-induced cell damage in H9c2 cells. Meanwhile, further studies suggested that lactate contributed to RIPC rescuing I/R-induced autophagy deficiency by promoting TFEB translocation to the nucleus through activating the AMPK-mTOR pathway without influencing the PI3K-Akt pathway, thus reducing cardiomyocytes damage. Interestingly, we also found that lactate upregulated the mRNA and protein expression of CX43 by facilitating the binding of TFEB to CX43 promoter in the myocardium. Functionally, silencing of TFEB attenuated the protective effect of lactate on cell damage, which was reversed by overexpression of CX43. Further mechanistic studies suggested lactate facilitated CX43-regulated autophagy via AMPK-mTOR-TFEB signaling pathway. Collectively, our research demonstrates that RIPC protects against myocardial I/R injury through lactate-mediated myocardial autophagy via AMPK-mTOR-TFEB-CX43 axis.

Cai's herbal tea enhances mitochondrial autophagy of type 1 diabetic mellitus β cells through the AMPK/mTOR pathway and alleviates inflammatory response.

This study investigates the therapeutic mechanisms of Cai's Herbal Tea in Type 1 Diabetes Mellitus (T1DM) mice, focusing on its effects on mitochondrial change and autophagy via the AMP-activated protein kinase (AMPK)-mammalian target of rapamycin (mTOR) pathway. The composition of Cai's Herbal Tea was analyzed by Ultra-High Performance Liquid Chromatography-Quadrupole Time of Flight Mass Spectrometry (UHPLC-Q/TOF-MS). C57BL/6 mice and Min6 pancreatic beta cells were divided into control, diabetic mellitus (DM)/high glucose (HG), and treatment groups (low, medium, and high doses of Cai's Tea, and Metformin). Key physiological parameters, pancreatic islet health, Min6 cell morphology, viability, and insulin (INS) secretion were assessed. Small Interfering RNA-AMPK (si-AMPK) was utilized to confirm the pathway involvement. Cai's Herbal Tea improved body weight, pancreatic islet pathological injury, and INS secretion whereas reduced total triglycerides, fasting blood sugar, and Interferon gamma (INF-γ) in T1DM mice, particularly at higher doses. In Min6 cells, Cai's Tea mitigated HG-induced damage and proinflammatory response, enhancing cell viability and INS secretion. Notably, it reduced swelling and improved cristae structure in treated groups of mitochondria and promoted autophagy via the AMPK-mTOR pathway, evidenced by increased LC3II/LC3I and P-AMPK/AMPK ratios, and decreased P-mTOR/mTOR and P62 expressions in pancreatic islet β-cells. Furthermore, these effects were converted by si-AMPK interference. Cai's Herbal Tea exhibits significant therapeutic efficacy in T1DM mice by improving mitochondrial health and inducing autophagy through the AMPK-mTOR pathway in pancreatic islet β-cells. These findings highlight its potential as a therapeutic approach for T1DM management.

Ginsenoside Rg1 inhibits multiple myeloma and overcomes bortezomib resistance through AMPK-mTOR pathway

BackgroundThe resistance of multiple myeloma (MM) to bortezomib (BTZ) has brought multiple challenges to its clinical use. Numerous ginsenosides have potential anti-tumor effects, however, the research on the role of Rg1 in MM has not been reported. ObjectiveTo examine the inhibitory impact of Rg1 on the growth of MM and reduce the drug resistance of MM to BTZ through in vivo and in vitro experiments, and to explore their potential mechanism. MethodsBTZ drug-resistant cell line RPMI8226R was constructed. Mouse tumor-bearing model was developed by abdominal subcutaneous injection of MM cells. MM cells were treated with AMPK inhibitor Compound C or autophagy inhibitor Chloroquine together with Rg1. RPMI8226R cells were treated with BTZ and Rg1. Cell multiplication was detected using Methylthiazolyldiphenyl-tetrazolium bromide assay. Apoptosis was assessed using flow cytometry. Immunofluorescence assay was employed to assess the autophagy markers LC3. Western blot was utilized to assess the protein expression. Immunohistochemistry was used to detect cell proliferation and apoptosis in tumor tissues. ResultsIn vitro experiments demonstrated that Rg1 could hinder the proliferation of MM cells, promote apoptosis and enhance autophagy. Rg1 could also increase the sensitivity of RPMI8226R to BTZ. In vivo experiments illustrated that Rg1 could hinder the development of MM cells in mice, weaken the proliferation of tumor cells and enhance their apoptosis. Further study found that the anti-MM impact of Rg1 was linked to AMPK-mTOR pathway, the autophagy degree of RPMI8226R was higher than that of RPMI8226, and that Rg1 could inhibit MM and overcome drug resistance through autophagy induced by AMPK-mTOR pathway. ConclusionRg1 has significant anti-MM effect and can overcome BTZ resistance, and its potential mechanism is related to the regulation of autophagy induced by AMPK-mTOR pathway. Rg1 is a promising adjuvant drug for the treatment of MM.

Treatment of Rheumatoid Arthritis Based on the Inherent Bioactivity of Black Phosphorus Nanosheets.

Rheumatoid arthritis (RA) is an autoimmune disease that affects the living quality of patients, especially the elderly population. RA-related morbidity and mortality increase significantly with age, while current clinical drugs for RA are far from satisfactory and may have serious side effects. Therefore, the development of new drugs with higher biosafety and efficacy is demanding. Black phosphorus nanosheets (BPNSs) have been widely studied because of their excellent biocompatibility. Here, we focus on the inherent bioactivity of BPNSs, report the potential of BPNSs as a therapeutic drug for RA and elucidate the underlying therapeutic mechanism. We find that BPNSs inhibit autophagy at an early stage via the AMPK-mTOR pathway, switch the energy metabolic pathway to oxidative phosphorylation, increase intracellular ATP levels, suppress apoptosis, reduce inflammation and oxidative stress, and down-regulate senescence-associated secretory phenotype (SASP)-related genes in rheumatoid arthritis synovial fibroblasts (RA-SFs). Further, BPNSs induce the apoptosis of macrophages and promote their transition from the M1 to the M2 phenotype by regulating related cytokines. Significantly, the administration of BPNSs can alleviate key pathological features of RA in mice, revealing great therapeutic potential. This study provides a novel option for treating RA, with BPNSs emerging as a promising therapeutic candidate.

ANXA1sp modulates the protective effect of Sirt3-induced mitophagy against sepsis-induced myocardial injury in mice.

Sepsis-induced myocardial injury (SIMI) may be associated with insufficient mitophagy in cardiomyocytes, but the exact mechanism involved remains unknown. Sirtuin 3 (Sirt3) is mainly found in the mitochondrial matrix and is involved in repairing mitochondrial function through means such as the activation of autophagy. Previously, we demonstrated that the annexin-A1 small peptide (ANXA1sp) can promote Sirt3 expression in mitochondria. In this study, we hypothesized that the activation of Sirt3 by ANXA1sp induces mitophagy, thereby providing a protective effect against SIMI in mice. A mouse model of SIMI was established via cecal ligation and puncture. Intraperitoneal injections of ANXA1sp, 3TYP, and 3MA were administered prior to modeling. After successful modeling, IL-6, TNF-α, CK-MB, and CTn-I levels were measured; cardiac function was assessed using echocardiography; myocardial mitochondrial membrane potential, ROS, and ATP production were determined; myocardial mitochondrial ultrastructure was observed using transmission electron microscopy; and the expression levels of Sirt3 and autophagy-related proteins were detected using western blotting. ANXA1sp significantly reduced serum IL-6, TNF-α, CK-MB, and CTn-I levels; decreased myocardial ROS production; increased mitochondrial membrane potential and ATP synthesis; and improved myocardial mitochondrial ultrastructure in septic mice. Furthermore, ANXA1sp promoted Sirt3 expression and activated the AMPK-mTOR pathway to induce myocardial mitophagy. These protective effects of ANXA1sp were reversed upon treatment with the Sirt3 blocker, 3-TYP. ANXA1sp can reverse SIMI, and the underlying mechanism may be related to the activation of the AMPK-mTOR pathway following upregulation of Sirt3 by ANXA1sp, which, in turn, induces autophagy.

Abstract 4549: Combinations of ciclopirox olamine and metformin exert synergistic antitumor activity in triple-negative breast cancer

Abstract Introduction: Triple-negative breast cancer (TNBC) represents a challenging subtype of breast cancer because of its limited treatment options. Recent research has highlighted the potential benefits of combining pharmacological agents to enhance therapeutic outcomes. Studies show that Ciclopirox olamine (CPX), an off-patent anti-fungal drug, induces cell cycle G1-phase arrest and activates the intrinsic apoptosis pathway by downregulating the anti-apoptotic proteins. Meanwhile, metformin, a safe and first-line drug for the treatment of type II diabetes, has been shown to induce cell cycle S-phase arrest and activates the extrinsic apoptosis pathway via induction of endogenous TRAIL in TNBC cells. However, whether the combinations of CPX and metformin would exert potent antitumor activity against TNBC remains unclear. Methods: Cell proliferation (MTS) assays and LIVE/DEAD cell imaging were used to determine the combined inhibitory effects on TNBC cells. IC50s and the combination index (CI) were calculated. Flow cytometry assays were carried out to analyze if the combinations are more potent to block cell cycle progression. Apoptotic-specific ELISA and flow cytometry analysis of Annexin V-PI staining were performed to assess if the combinations are significantly more effective to induce apoptosis. Western blot assays were used to examine if the combinations markedly induced the expression of TRAIL and cleavages of PARP and caspases. Tumor xenograft models will be established to test the in vivo antitumor activity of CPX and metformin either alone or in combinations. Results: Data indicated that both CPX and metformin independently inhibited the proliferation of TNBC cells. A synergistic effect was observed when CPX and metformin were used in combination, resulting in a more potent inhibition of TNBC cell proliferation. The combinatorial treatment effectively suppressed colony formation of TNBC cells. Synergy between CPX and metformin was partially linked to the enhanced activation of the AMPK-mTOR pathway, as the combination significantly enhanced the phosphorylation of AMPKα. The combinations also induced enhanced apoptosis in TNBC cells through both the intrinsic and extrinsic pathways. The combinatorial effects of CPX and metformin on in vivo tumor growth are under investigation. Conclusions: Combinations of CPX and metformin show synergistic effects on inhibiting TNBC cell proliferation. Our studies suggest a potential therapeutic strategy for TNBC, with the combinations of these agents exhibiting an enhanced antitumor activity. Further investigation is warranted to validate the results and explore their clinical applications. Key words: Triple-negative breast cancer, Ciclopirox olamine, Metformin, Combination, Apoptosis Citation Format: Yakun Wu, Hui Lyu, Congcong Tan, Margaret E. Larsen, Shile Huang, Bolin Liu. Combinations of ciclopirox olamine and metformin exert synergistic antitumor activity in triple-negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4549.

The mechanism of nickel-induced autophagy and its role in nephrotoxicity

Nickel (Ni), an environmental health hazard, is nephrotoxic to humans, but the exact mechanism is unknown. This study aims to identify whether nephrotoxicity is associated with autophagy. Here, nickel chloride (NiCl2) increased autophagy in TCMK-1 cells. NiCl2 induces autophagy through Akt and AMPK/mTOR pathways. Next, oxidative stress was investigated in NiCl2-induced autophagy. The findings demonstrated that the antioxidant (NAC) or mitochondrial targeted antioxidant (Mito-TEMPO) attenuated NiCl2-induced autophagy, reversed the influence on AMPK-mTOR and Akt pathways. Additionally, our study examined the role of autophagy in NiCl2-induced nephrotoxicity. Autophagy inhibition with 3-MA could inhibit cell viability and increase apoptosis in the TCMK-1 cells, however, autophagy promotion with rapamycin relieved cytotoxicity and decreased apoptosis. Additionally, co-treatment with Z-VAD-FMK reduced cytotoxicity, but did not affect autophagy. Besides, NiCl2 can increase the level of mitophagy in vivo and vitro. Mitophagy inhibition could inhibit cell viability and increase apoptosis in the TCMK-1 cells, whereas, promotion of mitophagy could increase cell viability and decrease apoptosis. In summary, above-mentioned results showed that NiCl2 induces autophagy in TCMK-1 cells through oxidative stress-dependent AMPK/AKT-mTOR pathway, autophagy plays a role in reducing NiCl2-induced renal toxicity, and a major mechanism in autophagy's inhibitory effect on NiCl2-induced apoptosis may be mitophagy.

PKM2 induces mitophagy through the AMPK-mTOR pathway promoting CSFV proliferation.

Viruses rely on the host cell's material-energy metabolic system for replication, inducing host metabolic disorders and subsequent immunosuppression-a major contributor to persistent viral infections. Classical swine fever virus (CSFV) is no exception. Classical swine fever is a severe acute infectious disease caused by CSFV, resulting in significant economic losses to the global pig industry. While the role of the metabolic enzyme PKM2 (pyruvate dehydrogenase) in the glycolytic pathway of tumor cells has been extensively studied, its involvement in viral infection remains relatively unknown. Our data unveil a new mechanism by which the metabolic enzyme PKM2 mediates CSFV infection, offering novel avenues for the development of antiviral strategies.

The Activation of GABAAR Alleviated Cerebral Ischemic Injury via the Suppression of Oxidative Stress, Autophagy, and Apoptosis Pathways.

Ischemic stroke is a devastating disease leading to neurologic impairment. Compounding the issue is the very limited array of available interventions. The activation of a γ-aminobutyric acid (GABA) type A receptor (GABAAR) has been reported to produce neuroprotective properties during cerebral ischemia, but its mechanism of action is not yet fully understood. Here, in a rat model of photochemically induced cerebral ischemia, we found that muscimol, a GABAAR agonist, modulated GABAergic signaling, ameliorated anxiety-like behaviors, and attenuated neuronal damage in rats suffering cerebral ischemia. Moreover, GABAAR activation improved brain antioxidant levels, reducing the accumulation of oxidative products, which was closely associated with the NO/NOS pathway. Notably, the inhibition of autophagy markedly relieved the neuronal insult caused by cerebral ischemia. We further established an oxygen-glucose deprivation (OGD)-induced PC12 cell injury model. Both in vivo and in vitro experiments demonstrated that GABAAR activation obviously suppressed autophagy by regulating the AMPK-mTOR pathway. Additionally, GABAAR activation inhibited apoptosis through inhibiting the Bax/Bcl-2 pathway. These data suggest that GABAAR activation exerts neuroprotective effects during cerebral ischemia through improving oxidative stress and inhibiting autophagy and apoptosis. Our findings indicate that GABAAR serves as a target for treating cerebral ischemia and highlight the GABAAR-mediated autophagy signaling pathway.

Effects of intermittent cold stimulation on growth performance, meat quality, antioxidant capacity and liver lipid metabolism in broiler chickens

Intermittent cold stimulation (ICS) enhances broilers’ resistance to cold stress. Nonetheless, further research is needed to investigate the underlying mechanisms that enhance cold stress resistance. A total of 160 one-day-old male Ross 308 broilers were randomly divided into two groups (CC and CS5), with the CC group managing temperature according to the standard for broiler growth stages, while the CS5 group were subjected to cold stimulation at a temperature 3℃ lower than the CC group for 5 h, every two days from 15-35 day. Sampling was conducted at 36 day (36D), 50 day (50D) and after acute cold stress for 24 h (Y24). First, we examined the effects of ICS on broiler growth performance, meat quality, antioxidant capacity, and lipid metabolism. The results demonstrated that ICS enhanced the performance of broilers to a certain degree. Specifically, the average weight gain in the CS5 group was significantly higher than that of the CC group, and the feed conversion ratio significantly decreased compared to CC at 4 W and 6 W (P ≤ 0.05). Compared with the CC group, cold stimulation significantly reduced drip loss, shearing force, and yellowness (a* value) of chicken meat, while significantly increased redness (b* value) (P ≤ 0.05). At Y24, the levels of T-AOC and GSH-PX in the serum of the CS5 group were significantly higher than those of the CC group, while the level of MDA was significantly lower (P ≤ 0.05). The content of TG, FFA, and VLDL in the serum of the CS5 group was significantly elevated, whereas the level of TC and HDL was significantly lower (P ≤ 0.05). In addition, we further explored whether AMPK-mTOR pathway is involved in the regulation of changes in lipid metabolism and the possible regulatory mechanisms downstream of the signaling pathway. The results showed that ICS significantly upregulated the expression levels of AMPK mRNA and protein in the liver of the CS5 group at 36D and Y24, while significantly down-regulating mTOR (P ≤ 0.05). Compared with the CC group, ICS significantly down-regulated the mRNA expression levels of lipid synthesis and endoplasmic reticulum stress-related genes (SREBP1c, FAS, SCD, ACC, GRP78 and PERK) at 36D and Y24, while significantly up-regulating the mRNA expression levels of lipid decomposition and autophagy-related genes (PPAR and LC3) (P ≤ 0.05). In addition, at Y24, the protein expression levels of endoplasmic reticulum stress-related genes (GRP78) in the CS5 group were significantly lower, while autophagy-related genes (LC3 and ATG7) were significantly higher (P ≤ 0.05). ICS can affect meat quality and lipid metabolism in broilers, and when broilers are subjected to acute cold stress, broilers trained with cold stimulation have stronger lipid metabolism capacity.

Ghrelin Induces the Production of Hypothalamic NPY Through the AMPK-mTOR Pathway to Alleviate Cancer-induced Bone Pain.

Cancer-induced bone pain (CIBP) is one of the most common symptoms of bone metastasis of tumor cells. The hypothalamus may play a pivotal role in the regulation of CIBP. However, little is known about the exact mechanisms. First, we established a CIBP model to explore the relationship among hypothalamic ghrelin, NPY and CIBP. Then, we exogenously administered NPY and NPY receptor antagonists to investigate whether hypothalamic NPY exerted an antinociceptive effect through binding to NPY receptors. Finally, we exogenously administered ghrelin to investigate whether ghrelin alleviated CIBP by inducing the production of hypothalamic NPY through the AMPK-mTOR pathway. Body weight, food intake and behavioral indicators of CIBP were measured every 3 days. Hypothalamic ghrelin, NPY and the AMPK-mTOR pathway were also measured. The expression of hypothalamic ghrelin and NPY was simultaneously decreased in cancer-bearing rats, which was accompanied by CIBP. Intracerebroventricular (i.c.v.) administration of NPY significantly alleviated CIBP in the short term. The antinociceptive effect of NPY was reversed with the i.c.v. administration of the Y1R and Y2R antagonists. The administration of ghrelin activated the AMPK-mTOR pathway and induced hypothalamic NPY production to alleviate CIBP. This effect of ghrelin on NPY and antinociception was reversed with the administration of a GHS-R1α antagonist. Ghrelin could induce the production of hypothalamic NPY through the AMPK-mTOR pathway to alleviate CIBP, which can provide a novel therapeutic mechanism for CIBP.

Activation of the AMPK-mTOR Pathway by Astaxanthin against Cold Ischemia-Reperfusion in Rat Liver.

Activation of the AMPK-mTOR Pathway by Astaxanthin against Cold Ischemia-Reperfusion in Rat Liver.

Exosomes from adipose-derived stem cells alleviate premature ovarian failure via blockage of autophagy and AMPK/mTOR pathway.

The objective of this study was to investigate the effects and mechanisms of adipose-derived stem cell-derived exosome (ADSCs-Exo) in treating premature ovarian failure (POF). We constructed a POF mouse model through intraperitoneal injection of cyclophosphamide, followed by the administration of the autophagy inhibitor 3-methyladenine (3-MA). Pathological injury, follicle stimulating hormone (FSH), malondialdehyde (MDA), reactive oxygen species (ROS), estradiol (E2), superoxide dismutase (SOD), granulosa cell (GC) apoptosis, and autophagy were assessed. Exosomes isolated from ADSCs were used to treat POF in mice. The AMPK-mTOR pathway and its proteins (p-AMPK and p-mTOR) were evaluated. A POF cell model was established using cyclophosphamide-treated human ovarian granulosa-like tumor (KGN) cells. We administered ADSCs-Exo and rapamycin to validate the mechanism of ADSCs-Exo against POF. In POF mice, 3-MA treatment attenuated pathological injuries, decreased FSH, MDA, and ROS levels, and increased E2 and SOD levels. 3-MA treatment also inhibited GC apoptosis and autophagy. ADSCs-Exo alleviated pathological injuries, improved ovarian morphology and function, and reduced oxidative stress in POF mice. ADSCs-Exo inhibited GC apoptosis and autophagy. ADSCs-Exo downregulated the expression of AMPK/mTOR pathway proteins (p-AMPK and p-mTOR). In the POF cell model, ADSCs-Exo and rapamycin inhibited AMPK/mTOR-mediated autophagy. ADSCs-Exo inhibits POF through the inhibition of autophagy and the AMPK/mTOR pathway. This study provides a potential target for the clinical treatment of POF.

Hydrogen sulfide inhibits gene expression associated with aortic valve degeneration by inducing NRF2-related pro-autophagy effect in human aortic valve interstitial cells.

Aortic valve stenosis (AS) is the most common valvular heart disease but there are currently no effective medical treatments that can delay disease progression due to a lack of knowledge of the precise pathophysiology. The expression of sulfide: quinone oxidoreductase (SQOR) and nuclear factor erythroid 2-related factor 2 (NRF2) was decreased in the aortic valve of AS patients. However, the role of SQOR and NRF2 in the pathophysiology of AS has not been found. We investigated the effects of hydrogen sulfide (H2S)-releasing compounds on diseased aortic valve interstitial cells (AVICs) to explain the cellular mechanism of SQOR and elucidate the medical value of H2S for AS treatment. Sodium hydrosulfide (NaHS) treatment increased the expression of SQOR and NRF2 gene and consequently induced the NRF2 target genes, such as NAD(P)H quinone dehydrogenase 1 and cystathionine γ-lyase. In addition, NaHS dose-dependently decreased the expression level of fibrosis and inflammation-related genes (MMP9, TNF-α, IL6) and calcification-related genes (ALP, osteocalcin, RUNX2, COL1A1) in human AVICs. Furthermore, NaHS activated the AMPK-mTOR pathway and inhibited the PI3K-AKT pathway, resulting in a pro-autophagy effect in human AVICs. An NRF2 inhibitor, brusatol, attenuated NaHS-induced AMPK activation and decreased the autophagy markers Beclin-1 and LC3AB, suggesting that the mechanism of action of H2S is related to NRF2. In conclusion, H2S decreased gene expression levels related to aortic valve degeneration and activated AMPK-mTOR-mediated pro-autophagy function associated with NRF2 in human AVICs. Therefore, H2S could be a potential therapeutic target for the development of AS treatment.

Metformin Reduces the Progression of Atherogenesis by Regulating the Sestrin2-mTOR Pathway in Obese and Diabetic Rats.

In previous research, we found that Sestrin2 has a strong association with plasma atherogenicity and combats the progression of atherogenesis by regulating the AMPK-mTOR pathway. Metformin, an activator of AMPK, is widely used as a first-line therapy for diabetes, but its role in preventing atherosclerosis and cardiac outcomes is unclear. Hence, we aimed to assess the effect of metformin on preventing atherosclerosis and its regulatory role in the Sestrin2-AMPK -mTOR pathway in obese/diabetic rats. Animals were fed a high-fat diet to induce obesity, administered streptozotocin to induce diabetes, and then treated with metformin (150 mg/kg body weight) for 14 weeks. Aorta and heart tissues were analyzed for Sestrin2 status by western blotting and immunohistochemistry, AMPK and mTOR activities were investigated using western blotting, and atherogenicity-related events were evaluated using reverse transcription quantitative polymerase chain reaction and histology. Obese and diabetic rats showed significant decrease in Sestrin2 levels and AMPK activity, accompanied by increased mTOR activity in the heart and aorta tissues. Metformin treatment significantly restored Sestrin2 and AMPK levels, reduced mTOR activity, and restored the altered expression of inflammatory markers and adhesion molecules in obese and diabetic rats to normal levels. A histological analysis of samples from obese and diabetic rats showed atherosclerotic lesions both in aorta and heart tissues. The metformin-treated rats showed a decrease in atherosclerotic lesions, cardiac hypertrophy, and cardiomyocyte degeneration. This study presents further insights into the beneficial effects of metformin and its protective role against atherosclerosis through regulation of the Sestrin2-AMPK-mTOR pathway.

Metformin has anti-inflammatory effects and induces immunometabolic reprogramming via multiple mechanisms in hidradenitis suppurativa.

Targeting immunometabolism has shown promise in treating autoimmune and inflammatory conditions. Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease involving painful lesions in apocrine gland-bearing skin. Therapeutic options for HS are limited and often ineffective; thus, there is a pressing need for improved treatments. To date, metabolic dysregulation has not been investigated in HS. As HS is highly inflammatory, we hypothesized that energy metabolism is dysregulated in these patients. Metformin, an antidiabetic drug, which is known to impact on cellular metabolic and signalling pathways, has been shown to have anti-inflammatory effects in cancer and arthritis. While metformin is not licensed for use in HS, patients with HS taking metformin show improved clinical symptoms. To assess the effect and mechanism of action of metformin in HS. To assess the effect of metformin in vivo, we compared the immune and metabolic profiles of peripheral blood mononuclear cells (PBMCs) of patients with HS taking metformin vs. those not taking metformin. To examine the effect of metformin treatment ex vivo, we employed a skin explant model on skin biopsies from patients with HS not taking metformin, which we cultured with metformin overnight. We used enzyme-linked immunosorbent assays, multiplex cytokine assays and quantitative real-time polymerase chain reaction (RT-PCR) to measure inflammatory markers, and Seahorse flux technology and quantitative RT-PCR to assess glucose metabolism. We showed that metabolic pathways are dysregulated in the PBMCs of patients with HS vs. healthy individuals. In metformin-treated patients, these metabolic pathways were restored and their PBMCs had reduced inflammatory markers following long-term metformin treatment. In the skin explant model, we found that overnight culture with metformin reduced inflammatory cytokines and chemokines and glycolytic genes in lesions and tracts of patients with HS. Using in vitro assays, we found that metformin may induce these changes via the NLR family pyrin domain containing 3 (NLRP3) inflammasome and the AMP-activated protein kinase (AMPK)-mammalian target of rapamycin (mTOR) pathway, which is linked to glycolysis and protein synthesis. Our study provides insight into the mechanisms of action of metformin in HS. The anti-inflammatory effects of metformin support its use as a therapeutic agent in HS, while its effects on immunometabolism suggest that targeting metabolism is a promising therapeutic option in inflammatory diseases, including HS.

Therapeutic effects on the development of heart failure with preserved ejection fraction by the sodium-glucose cotransporter 2 inhibitor dapagliflozin in type 2 diabetes

BackgroundHeart failure with preserved ejection fraction (HFpEF) is a common disease with high morbidity and lacks effective treatment. We investigated the protective effects of the long-term application of the sodium-glucose cotransporter 2 inhibitor (SGLT2i) dapagliflozin on diabetes-associated HFpEF in a rat model. Serum proteomics and metabolomics analysis were also conducted in type 2 diabetic patients with HFpEF treated with dapagliflozin.MethodsMale Zucker diabetic fatty (ZDF) rats were used as a model of diabetic cardiomyopathy. From weeks 16 to 28, animals were given a vehicle or dapagliflozin (1 mg/kg) once daily. Primary blood biochemistry indices, echocardiography, histopathology, and cardiac hemodynamics were determined during the study period. The key markers of myocardial fibrosis, nitro-oxidative stress, inflammation, apoptosis, autophagy, and AMPK/mTOR signaling were examined. Additionally, healthy controls and individuals with type 2 diabetes were enrolled and 16 serum samples from 4 groups were randomly selected. Serum proteome and metabolome changes after dapagliflozin treatment were analyzed in diabetic individuals with HFpEF.ResultsDapagliflozin effectively prevented the development of HFpEF in rats with diabetes by mitigating nitro-oxidative stress, pro-inflammatory cytokines, myocardial hypertrophy, and fibrosis, reducing apoptosis, and restoring autophagy through AMPK activating and mTOR pathway repressing. Proteomics and metabolomics revealed that cholesterol and high-density lipoprotein particle metabolism, nicotinate and nicotinamide metabolism, arginine biosynthesis, and cAMP and peroxisome proliferator-activated receptor (PPAR) signaling are the major disturbed pathways in HFpEF patients treated with dapagliflozin.ConclusionLong-term treatment with dapagliflozin significantly prevented the development of HFpEF in diabetic rats. Dapagliflozin could be a promising therapeutic strategy in managing HFpEF individuals with type 2 diabetes.

Low rumen degradable starch promotes the growth performance of goats by increasing protein synthesis in skeletal muscle via the AMPK-mTOR pathway.

Since starch digestion in the small intestine provides more energy than digestion in the rumen of ruminants, reducing dietary rumen degradable starch (RDS) content is beneficial for improving energy utilization of starch in ruminants. The present study tested whether the reduction of rumen degradable starch by restricting dietary corn processing for growing goats could improve growth performance, and further investigated the possible underlying mechanism. In this study, twenty-four 12-wk-old goats were selected and randomly allocated to receive either a high RDS diet (HRDS, crushed corn-based concentrate, the mean of particle sizes of corn grain=1.64mm, n=12) or a low RDS diet (LRDS, non-processed corn-based concentrate, the mean of particle sizes of corn grain >8mm, n=12). Growth performance, carcass traits, plasma biochemical indices, gene expression of glucose and amino acid transporters, and protein expression of the AMPK-mTOR pathway were measured. Compared to the HRDS, LRDS tended to increase the average daily gain (ADG, P=0.054) and decreased the feed-to-gain ratio (F/G, P<0.05). Furthermore, LRDS increased the net lean tissue rate (P<0.01), protein content (P<0.05) and total free amino acids (P<0.05) in the biceps femoris (BF) muscle of goats. LRDS increased the glucose concentration (P<0.01), but reduced total amino acid concentration (P<0.05) and tended to reduce blood urea nitrogen (BUN) concentration (P=0.062) in plasma of goats. The mRNA expression of insulin receptors (INSR), glucose transporter 4 (GLUT4), L-type amino acid transporter 1 (LAT1) and 4F2 heavy chain (4F2hc) in BF muscle, and sodium-glucose cotransporters 1 (SGLT1) and glucose transporter 2 (GLUT2) in the small intestine were significantly increased (P<0.05) in LRDS goats. LRDS also led to marked activation of p70-S6 kinase (S6K) (P<0.05), but lower activation of AMP-activated protein kinase (AMPK) (P<0.05) and eukaryotic initiation factor 2α (P<0.01). Our findings suggested that reducing the content of dietary RDS enhanced postruminal starch digestion and increased plasma glucose, thereby improving amino acid utilization and promoting protein synthesis in the skeletal muscle of goats via the AMPK-mTOR pathway. These changes may contribute to improvement in growth performance and carcass traits in LRDS goats.

A novel biguanide derivative, IM176, induces prostate cancer cell death by modulating the AMPK-mTOR and androgen receptor signaling pathways

Metformin and phenformin, biguanide derivatives that are widely used to treat type 2 diabetes mellitus, have recently been shown to exert potential anticancer effects in prostate cancer. This study compared the anti-prostate cancer effects of the novel biguanide derivative IM176 with those of metformin and phenformin. Prostate cancer cell lines and patient-derived castration-resistant prostate cancer (CRPC) cells were treated with IMI76, metformin, and phenformin. The effects of these agents on cell viability, annexin V-FITC apoptosis, mTOR inhibition, protein expression and phosphorylation, and gene expression were evaluated. IM176 dose-dependently reduced the viability of all prostate cancer cell lines tested, with IC 50 s (LNCaP: 18.5 μM; 22Rv1: 36.8 μM) lower than those of metformin and phenformin. IM176 activated AMP-activated protein kinase (AMPK), inhibiting mTOR and reducing the phosphorylation of p70S6K1 and S6. IM176 inhibited the expression of androgen receptor (AR), the AR splice variant 7 (AR-V7) and prostate-specific antigen in LNCaP and 22Rv1 cells. IM176 increased caspase-3 cleavage and annexin V-positive/PI-positive cells, which indicated apoptosis. Moreover, IM176 reduced viability, with low IC 50 , in cultured cells derived from two patients with CRPC. The antitumor effects of IM176 were comparable with those of other biguanides. IM176 may therefore be a novel candidate for the treatment of patients with prostate cancer, including those with CRPC.