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Autophagy is a lysosome‐mediated self‐degradation process of central importance for cellular quality control. It also provides macromolecule building blocks and substrates for energy metabolism during nutrient or energy deficiency, which are the main stimuli for autophagy induction. However, like most biological processes, autophagy itself requires ATP, and there is an energy threshold for its initiation and execution. We here present the first comprehensive review of this often‐overlooked aspect of autophagy research. The studies in which ATP deficiency suppressed autophagy in vitro and in vivo were classified according to the energy pathway involved (oxidative phosphorylation or glycolysis). A mechanistic insight was provided by pinpointing the critical ATP‐consuming autophagic events, including transcription/translation/interaction of autophagy‐related molecules, autophagosome formation/elongation, autophagosome fusion with the lysosome, and lysosome acidification. The significance of energy‐dependent fine‐tuning of autophagic response for preserving the cell homeostasis, and potential implications for the therapy of cancer, autoimmunity, metabolic disorders, and neurodegeneration are discussed. [ABSTRACT FROM AUTHOR]

BACKGROUND Hypertension may result in atrial fibrillation (AF) and lipid metabolism disorders. The Sirtuins3 (SIRT3)/AMP-activated protein kinase (AMPK) signaling pathway has the capacity to regulate lipid metabolism disorders and the onset of AF. We hypothesize that the SIRT3/AMPK signaling pathway suppresses lipid metabolism disorders, thereby mitigating salt-sensitive hypertension (SSHT)-induced susceptibility to AF. METHODS The study involved 7-week-old male Dahl salt-sensitive that were fed either a high-salt diet (8% NaCl; DSH group) or a normal diet (0.3% NaCl; DSN group). Then DSH group was administered either oral metformin (MET, an AMPK agonist) or intraperitoneal injection of Honokiol (HK, a SIRT3 agonist). This experimental model allowed for the measurement of Systolic blood pressure (SBP), the expression levels of lipid metabolism-related biomarkers, pathological examination of atrial fibrosis, and lipid accumulation, as well as AF inducibility and AF duration. RESULTS DSH decrease SIRT3, phosphorylation-AMPK, and very long-chain acyl-CoA dehydrogenase, (VLCAD) expression, increased FASN and FABP4 expression and concentrations of free fatty acid and triglyceride, atrial fibrosis and lipid accumulation in atrial tissue, enhanced level of SBP, promoted AF induction rate and prolonged AF duration, which are blocked by MET and HK. Our results also showed that the degree of atrial fibrosis was negatively correlated with VLCAD expression, but positively correlated with the expression of FASN and FABP4. CONCLUSIONS We have confirmed that a high-salt diet can result in hypertension, and associated atrial tissue lipid metabolism dysfunction. This condition is linked to the inhibition of the SIRT3/AMPK signaling pathway, which plays a significant role in the progression of susceptibility to AF in SSHT rats. [ABSTRACT FROM AUTHOR]

Aims/hypothesis: Appropriate management of blood glucose levels and the prevention of complications are important in the treatment of diabetes. We have previously reported on a compound named HPH-15 that is not only antifibrotic but also AMP-activated protein kinase (AMPK)-activating. In this study, we evaluated whether HPH-15 is useful as a therapeutic medication for diabetes. Methods: We examined the effects of HPH-15 on AMPK activation, glucose uptake, fat accumulation and lactic acid production in L6-GLUT4, HepG2 and 3T3-L1 cells, as a model of muscle, liver and fat tissue, respectively. Additionally, we investigated the glucose-lowering, fat-accumulation-suppressing, antifibrotic and AMPK-activating effect of HPH-15 in mice fed a high-fat diet (HFD). Results: HPH-15 at a concentration of 10 µmol/l increased AMPK activation, glucose uptake and membrane translocation of GLUT4 in each cell model to the same extent as metformin at 2 mmol/l. The production of lactic acid (which causes lactic acidosis) in HPH-15-treated cells was equal to or less than that observed in metformin-treated cells. In HFD-fed mice, HPH-15 lowered blood glucose from 11.1±0.3 mmol/l to 8.2±0.4 mmol/l (10 mg/kg) and 7.9±0.4 mmol/l (100 mg/kg) and improved insulin resistance. The HPH-15 (10 mg/kg) group showed the same level of AMPK activation as the metformin (300 mg/kg) group in all organs. The HPH-15-treated HFD-fed mice also showed suppression of fat accumulation and fibrosis in the liver and fat tissue; these effects were more significant than those obtained with metformin. Mice treated with high doses of HPH-15 also exhibited a 44% reduction in subcutaneous fat. Conclusions/interpretation: HPH-15 activated AMPK at lower concentrations than metformin in vitro and in vivo and improved blood glucose levels and insulin resistance in vivo. In addition, HPH-15 was more effective than metformin at ameliorating fatty liver and adipocyte hypertrophy in HFD-fed mice. HPH-15 could be effective in preventing fatty liver, a common complication in diabetic individuals. Additionally, in contrast to metformin, high doses of HPH-15 reduced subcutaneous fat in HFD-fed mice. Presumably, HPH-15 has a stronger inhibitory effect on fat accumulation and fibrosis than metformin, accounting for the reduction of subcutaneous fat. Therefore, HPH-15 is potentially a glucose-lowering medication that can lower blood glucose, inhibit fat accumulation and ameliorate liver fibrosis. [ABSTRACT FROM AUTHOR]

The neurotoxicant trimethyltin (TMT) triggers cognitive impairment and hippocampal neurodegeneration. TMT is a useful research tool for the study of Alzheimer's disease (AD) pathogenesis and treatment. Although the antidiabetic agent metformin has shown promising neuroprotective effects, however, its precise modes of action in neurodegenerative disorders need to be further elucidated. In this study, we investigated whether metformin can mitigate TMT cognition impairment and hippocampal neurodegeneration. To induce an AD-like phenotype, TMT was injected i.p. (8 mg/kg) and metformin was administered daily p.o. for 3 weeks at 200 mg/kg. Our results showed that metformin administration to the TMT group mitigated learning and memory impairment in Barnes maze, novel object recognition (NOR) task, and Y maze, attenuated hippocampal oxidative, inflammatory, and cell death/pyroptotic factors, and also reversed neurodegeneration-related proteins such as presenilin 1 and p-Tau. Hippocampal level of AMP-activated protein kinase (AMPK) as a key regulator of energy homeostasis was also improved following metformin treatment. Additionally, metformin reduced hippocampal acetylcholinesterase (AChE) activity, glial fibrillary acidic protein (GFAP)-positive reactivity, and prevented the loss of CA1 pyramidal neurons. This study showed that metformin mitigated TMT-induced neurodegeneration and this may pave the way to develop new therapeutics to combat against cognitive deficits under neurotoxic conditions. [ABSTRACT FROM AUTHOR]

Objective:To explore the possible role of ginkgolide K (GK) in the treatment of traumatic brain injury (TBI) and analyze its effect on AMP-activated protein kinase (AMPK) activity.Methods:Rats were divided into Sham group,TBI group,L-GK group,M-GK group,H-GK group,and H-GK+CC group (n=11) .Rats in Sham group was sham-operated rats,and rats in other groups were TBI model rats which made by craniocerebral injury instrument.Rats in Sham group and TBI group were administered 0.5%CMC-Na by intragastric administration.Rats in L-GK group,M-GK group,and H-GK group were administered 2,4,and 8 mg/kg/d ginkgolide K respectively.Rats in H-GK+CC group were given with 8 mg/kg/d Ginkgolide K and intraperitoneally injected with 20 mg/kg/d of AMPK inhibitor Compound C (CC) .Rats were all dosed for 14 days.Neurological function was assessed by the modified Neurological Severity Score (mNSS) .The Morris water maze test was used to evaluate cognitive function,and the escape latency (EL) and the number of platform crossings within 1 min (NPC) were recorded.Brain tissue sections were subjected to HE,Nissl and TUNEL staining as well as Bax and Bcl-2 immunohistochemical staining.The levels of SOD,CAT,GSH-Px,MDA,IL-1β,IL-6 and TNF-α,the activities of Na+-K+-ATPase and Ca2+-Mg2+-ATPase and the content of ATP in brain tissue were detected according to the kit instructions.The serum levels of NO and T-NOS were detected by colorimetry.The protein expression levels of p-AMPKα (Thr172),p62 and Beclin-1 in brain tissue were detected by Western blot.Results:Compared with Sham group,the mNSS score and EL of TBI group increased (P＜0.05),the NPC decreased (P＜0.05),the HE staining score increased (P＜0.05),the TUNEL positivity rate and Bax staining score increased (P＜0.05),the Bcl-2 staining score decreased (P＜0.05),the levels of MDA,IL-1β,IL-6,TNF-α,NO and T-NOS increased (P＜0.05),the levels of SOD,CAT and GSH-Px decreased (P＜0.05),the activities of Na+-K+-ATPase and Ca2+-Mg2+-ATPase and ATP content decreased (P＜0.05),the relative expression levels of p-AMPKα (Thr172) and Beclin-1 protein decreased (P＜0.05),and the relative expression levels of p62 protein increased (P＜0.05) .Compared with TBI group,the mNSS score and EL of L-GK,M-GK and H-GK groups decreased (P＜0.05),the NPC increased (P＜0.05),the HE staining score decreased (P＜0.05),the TUNEL positive rate and Bax staining score decreased (P＜0.05),the Bcl-2 staining score increased (P＜0.05), the levels of MDA,IL-1β,IL-6,TNF-α,NO and T-NOS decreased (P＜0.05),the levels of SOD,CAT and GSH-Px increase (P＜0.05),the activities of Na+-K+-ATPase and Ca2+-Mg2+-ATPase and ATP content increased (P＜0.05),the relative expression level of p-AMPKα (Thr172) and Beclin-1 protein increased (P＜0.05),and the relative expression level of p62 protein decreased (P＜0.05) .Compared with H-GK group,the mNSS score and EL of H-GK+CC group increased (P＜0.05),the NPC decreased (P＜0.05),the HE staining score increased (P＜0.05),the TUNEL positivity rate and Bax staining score increased (P＜0.05),the Bcl-2 staining score decreased (P＜0.05),the levels of SOD,CAT and GSH-Px decreased (P＜0.05),the levels of MDA,IL-1β,IL-6,TNF-α,NO and T-NOS increased (P＜0.05),the activities of Na+-K+-ATPase and Ca2+-Mg2+-ATPase and ATP content decreased (P＜0.05), the relative expression levels of p-AMPKα (Thr172) and Beclin-1 protein decreased (P＜0.05),and the relative expression levels of p62 protein increased (P＜0.05) .Conclusion:Ginkgolide K could alleviate brain damage in TBI rats by improving AMPK-mediated energy metabolism and autophagy. MoreReset [ABSTRACT FROM AUTHOR]

Introduction: Diabetes mellitus is known to provoke devastating anomalies in myocardial structure and function, while effective therapeutic regimen is still lacking. The selective protease inhibitor UCF101 (5-[5-(2-nitrophenyl) furfuryl iodine]-1,3-diphenyl-2-thiobarbituric acid) has been shown to fend off ischemic heart injury, although its impact on diabetic cardiomyopathy remains elusive. Methods: Our present work was conducted to examine the effect of UCF101 on experimental diabetes-evoked cardiac geometric and functional abnormalities as well as mechanisms involved. Adult mice were made diabetic using streptozotocin (STZ, 50 mg/kg, i.p., for 5 days) while receiving UCF101 (7.15 mg/kg, i.p.). Results: STZ evoked cardiac hypertrophy, interstitial fibrosis, mitochondrial ultrastructural damage, oxidative stress, dampened autophagy (LC3B, Beclin 1, elevated p62), mitophagy (FUNDC1 and Parkin with upregulated TOM20), increased left ventricular end systolic diameter, reduced fractional shortening, ejection fraction, cardiomyocyte shortening capacity, velocities of shortening/re-lengthening, and rise in intracellular Ca2+ in conjunction with elongated diastole and intracellular Ca2+ removal, the responses were overtly reconciled by UCF101 with little effects from UCF101 itself. Levels of cell injury markers Omi/HtrA2, TNFα, and stress signaling (JNK, ERK, p38) were overtly enhanced along with compromised phosphorylation of cellular fuel AMP-activated protein kinase (AMPK) (Thr172) and cell survival molecule GSK3β, as well as downregulated SERCA2a and elevated phospholamban, the effect was reversed by UCF101 (except for SERCA2a). AMPK knockout, pharmacological inhibition, the mitophagy inhibitor liensinine, and parkin knockout nullified UCF101-offered cardioprotection in diabetes. UCF101 reversed STZ-induced upregulation in the AMPK degrading enzymes PP2A and PP2C. Conclusion: These findings suggest that UCF101 rescues diabetes-mediated alterations in cardiac structure and function, likely through AMPK-mediated regulation of mitophagy. [ABSTRACT FROM AUTHOR]

Pomegranate polyphenol ellagic acid has medicinal potential in neurodegenerative disorders. The advantageous effect of this polyphenol in improving cognition in okadaic acid (OA)-instigated murine model with unraveling some modes of its action was assessed. Rats received ICV okadaic acid (OA) and post-treated with oral ellagic acid for 3 weeks (25 and 100 mg/kg/day). Cognition was analyzed in behavioral tasks besides assessment of oxidative, apoptotic, and inflammatory factors in addition to hippocampal histochemical analysis. Ellagic acid at a dose of 100 mg/kg properly attenuated cognitive abnormalities in novel object recognition (NOR), Y maze, and Barnes maze tests. Additionally, ellagic acid diminished hippocampal changes of malondialdehyde (MDA), protein carbonyl, reactive oxygen species (ROS), glutathione (GSH), glutathione peroxidase, superoxide dismutase (SOD), apoptotic factors caspases 1 and 3, tumor necrosis factor α (TNFα), and acetylcholinesterase (AChE) and beta secretase 1 (BACE 1) besides reversal of AMP-activated protein kinase (AMPK) and hyperphosphorylated tau (p-tau). Moreover, lower glial fibrillary acidic protein (GFAP) and less injury of hippocampal CA1 pyramidal neurons were observed upon ellagic acid. To conclude, neuroprotective potential of ellagic acid was shown which is somewhat attributable to its reversal of oxidative, apoptotic, and neuroinflammatory events in addition to proper regulation of AMPK and p-tau. [ABSTRACT FROM AUTHOR]

Background: Small‐cell lung cancer (SCLC) shows high enhancer of zeste homolog 2 (EZH2) expressions. EZH2‐mediated epigenetics promote epithelial‐mesenchymal transition (EMT), enhancing invasive and metastatic potential in malignancies. MicroRNAs (miRNAs), small noncoding RNAs, modulate EMT, determining tumor phenotypes. However, the association between miRNAs and EZH2 in SCLC remains to be clarified—we aimed to identify a novel tumorigenic mechanism through miRNAs, EZH2, and EMT in SCLC, leading to future therapeutic applications. Methods: We analyzed EZH2 and E‐cadherin expressions in lung cancer cell lines and tumor tissues from 34 SCLC patients and confirmed EZH2 siRNA‐mediated EMT inhibition. miRNA expression profiles were compared between EZH2 knockdown SCLC cells and negative control SCLC cells using miRNA array. We identified a target miRNA of EZH2 showing expressional differences in EZH2‐knockdown cells and analyzed the impact of the miRNA on EZH2‐mediated EMT and tumorigenesis. Results: All SCLC cells showed increased EZH2 and decreased E‐cadherin expressions. SCLC tissues had higher EZH2 and lower E‐cadherin expressions than other lung cancer tissues. miRNA array revealed that miR‐4448 expression increased in EZH2‐knockdown SCLC cells. miR‐4448 overexpression reduced tumor cell growth and prevented EMT. miR‐4448 bound to the 3′UTR of the girdin gene and suppressed its expression, thereby decreasing Akt phosphorylation at Ser473. Attenuated Akt phosphorylation resulted in AMP‐activated protein kinase (AMPK) phosphorylation at Thr172 and 183, enhancing EZH2 phosphorylation at Thr311. Conclusion: SCLC characterized high EZH2 expression and promoted EMT, compared with non‐small cell lung cancer. miR‐4448 inhibited Girdin expression, reducing Akt phosphorylation, and enhancing AMPK and EZH2 phosphorylation. Eventually, miR‐4448 prevented EZH2‐mediated EMT and tumorigenesis by modulating the Girdin/Akt/AMPK axis in SCLC. miR‐4448 might be a potential SCLC inhibitor. [ABSTRACT FROM AUTHOR]

The effects of trehalose, an autophagy-inducing disaccharide with neuroprotective properties, on the neurotoxicity of parkinsonian mimetics 6-hydroxydopamine (6-OHDA) and 1-methyl-4-phenylpiridinium (MPP+) are poorly understood. In our study, trehalose suppressed 6-OHDA-induced caspase-3/PARP1 cleavage (detected by immunoblotting), apoptotic DNA fragmentation/phosphatidylserine externalization, oxidative stress, mitochondrial depolarization (flow cytometry), and mitochondrial damage (electron microscopy) in SH-SY5Y neuroblastoma cells. The protection was not mediated by autophagy, autophagic receptor p62, or antioxidant enzymes superoxide dismutase and catalase. Trehalose suppressed 6-OHDA-induced activation of c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein kinase (MAPK), and AMP-activated protein kinase (AMPK), as revealed by immunoblotting. Pharmacological/genetic inhibition of JNK, p38 MAPK, or AMPK mimicked the trehalose-mediated cytoprotection. Trehalose did not affect the extracellular signal-regulated kinase (ERK) and mechanistic target of rapamycin complex 1 (mTORC1)/4EBP1 pathways, while it reduced the prosurvival mTORC2/AKT signaling. Finally, trehalose enhanced oxidative stress, mitochondrial damage, and apoptosis without decreasing JNK, p38 MAPK, AMPK, or AKT activation in SH-SY5Y cells exposed to MPP+. In conclusion, trehalose protects SH-SY5Y cells from 6-OHDA-induced oxidative stress, mitochondrial damage, and apoptosis through autophagy/p62-independent inhibition of JNK, p38 MAPK, and AMPK. The opposite effects of trehalose on the neurotoxicity of 6-OHDA and MPP+ suggest caution in its potential development as a neuroprotective agent. [ABSTRACT FROM AUTHOR]

Objectives: Galectin‐9 (Gal‐9) is an immune checkpoint ligand for T‐cell immunoglobulin and mucin domain 3. Although the roles of Gal‐9 in regulating immune responses have been well investigated, their biological roles have yet to be fully documented. This study aimed to analyse the expression of Gal‐9 bone marrow (BM) cells in C57BL/6J (B6) mice. Furthermore, the co‐expression of Gal‐9 with the mammalian target of rapamycin (mTOR) and AMP‐activated protein kinase (AMPK) was investigated. Methods: The BM cells in adult C57BL/6J (B6) mice were collected and analysed in vitro. Results: In a flow cytometric analysis of BM cells, Gal‐9 was highly expressed in c‐KithiSca‐1−CD34−CD71+ erythroid progenitors (EPs), whereas it was downregulated in more differentiated c‐KitloCD71+TER119+ cells. Subsequently, a negative selection of CD3−B220−Sca‐1−CD34−CD41−CD16/32− EPs was performed. This resulted in substantial enrichment of KithiCD71+Gal‐9+ cells and erythroid colony‐forming units (CFU‐Es), suggesting that the colony‐forming subset of EPs are included in the KithiCD71+Gal‐9+ population. Furthermore, we found that EPs had lower mTOR and AMPK expression levels in Gal‐9 knockout B6 mice than in wild‐type B6 mice. Conclusions: These results may stimulate further investigation of the role of Gal‐9 in haematopoiesis. [ABSTRACT FROM AUTHOR]

Ulcerative colitis (UC) is a subtype of inflammatory bowel disease affecting the colon with idiopathic origin. Melinjo endosperm extract (MeE) contains polyphenolic compounds that have antioxidative and anticancer properties. We examined the effect of MeE on inflammation and mucin expression in the colons of UC of mice treated with dextran sulfate sodium (DSS). C57BL/6J male mice were assigned into four categories: control, DSS + 0% MeE, DSS + 0.1% MeE, and DSS + 0.5% MeE. The control group was provided distilled water and a standard chow diet for 4 weeks. In DSS + 0% MeE, DSS + 0.1% MeE, and DSS + 0.5% MeE groups, the mice were treated with MeE for 3 weeks followed by MeE diets and drinking water containing 3% DSS for a week. Macrophage count, the mucus area stained by Alcian blue (AB), the levels of adenosine monophosphate-activated protein kinase (AMPK), nuclear factor-κB (NFκB) p65, and silent information regulator (Sirt) 1 protein expression, as well as proinflammatory mediators and Mucin 2 mRNA expression were assessed. In the DSS + 0% MeE group, the AB-stained areas and Mucin 2 mRNA expression levels were observed to be lower than those of controls. However, the levels in the +0.5% MeE group were significantly increased. Compared with the control group, the macrophage number, the expression of IL-1β mRNA, and NFκB p65 protein in the DSS + 0% MeE group showed a significant increase. Conversely, these levels were significantly decreased in the +0.5% MeE group. The phosphorylated AMPK and Sirt1 protein levels were upregulated in the +0.5% MeE group. In conclusion, MeE may alleviate UC injury by reducing macrophage infiltration and regulating the AMPK/NFκB/Sirt1 pathway. [ABSTRACT FROM AUTHOR]

Aim: Bile acids (BA) function as signalling molecules regulating glucose‐lipid homeostasis and energy expenditure. However, the expression of the apical sodium‐dependent bile acid transporter (ASBT) in the kidney, responsible for renal BA reabsorption, is downregulated in patients with diabetic kidney disease (DKD). Using the db/db mouse model of DKD, this study aimed to investigate the effects of rescuing ASBT expression via adeno‐associated virus‐mediated delivery of ASBT (AAVASBT) on kidney protection. Methods: Six‐week‐old male db/db mice received an intraparenchymal injection of AAVASBT at a dose of 1 × 1011 viral genomes (vg)/animal and were subsequently fed a chow diet for 2 weeks. Male db/m mice served as controls. For drug treatment, daily intraperitoneal (i.p.) injections of the farnesoid X receptor (FXR) antagonist guggulsterone (GS, 10 mg/kg) were administered one day after initiating the experiment. Results: AAVASBT treatment rescued renal ASBT expression and reduced the urinary BA output in db/db mice. AAVASBT treatment activated kidney mitochondrial biogenesis and ameliorated renal impairment associated with diabetes by activating FXR. In addition, the injection of FXR antagonist GS in DKD mice would reverse these beneficial effects by AAVASBT treatment. Conclusion: Our work indicated that restoring renal ASBT expression slowed the course of DKD via activating FXR. FXR activation stimulates mitochondrial biogenesis while reducing renal oxidative stress and lipid build up, indicating FXR activation's crucial role in preventing DKD. These findings further suggest that the maintenance of renal BA reabsorption could be a viable treatment for DKD. Summary at a glance: Restoring renal apical sodium‐dependent bile acid transporter (ASBT) expression attenuates diabetic kidney disease (DKD) progression through farnesoid X receptor activation, which promotes mitochondrial biogenesis and reduces oxidative stress and lipid accumulation.Modulating renal bile acid reabsorption via ASBT upregulation holds promise as a therapeutic approach for DKD management. [ABSTRACT FROM AUTHOR]

Background and Purpose Experimental Approach Key Results Conclusions and Interpretation Diabetic patients have an increased risk of psychiatric disorders. Because hyperglycaemia increases L‐lactate in the brain and L‐lactate inhibits AMP‐activated protein kinase (AMPK), this study investigated the role of L‐lactate and AMPK in strengthened fear memory, a model for human psychiatric disorders, in diabetic mice.The diabetic model was mice injected with streptozotocin. Fear memory was measured using the conditioned fear test with low (0.45 mA) or high (0.50 mA) foot shock to cause low and high freezing, respectively. Protein levels of AMPK and phosphorylated AMPK (pAMPK) were measured by western blotting and immunohistochemistry.At 0.45 mA, the AMPK inhibitor dorsomorphin increased freezing, which was inhibited by the AMPK activator acadesine. In contrast, at 0.50 mA, acadesine decreased freezing, which was inhibited by dorsomorphin. In diabetic mice, pAMPK was decreased in the amygdala and hippocampus. Diabetic mice showed increased freezing at 0.45 mA, which was inhibited by acadesine. In the amygdala and hippocampus, L‐lactate was increased in diabetic mice and injection of L‐lactate into non‐diabetic mice increased freezing at 0.45 mA. In addition, L‐lactate decreased pAMPK in the hippocampus, but not the amygdala, and increase in freezing induced by L‐lactate was inhibited by acadesine. Dorsomorphin‐induced increase in freezing was inhibited by the AMPA receptor antagonist NBQX.In diabetic mice, L‐lactate is increased in the amygdala and hippocampus, possibly through hyperglycaemia, which strengthens fear memory through inhibition of AMPK and activation of glutamatergic function. [ABSTRACT FROM AUTHOR]

8-Prenylgenistein (8PG), a genistein derivative, is present in fermented soybeans (Glycine max), including cheonggukjang (CGJ), and exhibits osteoprotective, osteogenic, and antiadipogenic properties. However, the hepatoprotective effects of 8PG and its underlying molecular mechanisms remain largely unexplored. Here, we identified the high binding affinity of 8PG with AMP-activated protein kinase (AMPK) and sirtuin 1 (SIRT1), which acts as a potent AMPK activator that counteracts hepatic steatosis. Notably, 8PG exhibited better pharmacokinetics with greater absorption and higher plasma binding than the positive controls for the target proteins. Moreover, 8PG exerted non-carcinogenic activity in rats and significantly increased AMPK phosphorylation. Compound C, an AMPK inhibitor, did not antagonize 8PG-activated AMPK in HepG2 cells. 8PG significantly attenuated palmitate-induced lipid accumulation and enhanced phosphorylated AMPK and its downstream target, acetyl-CoA carboxylase. Further, 8PG activated nuclear SIRT1 at the protein level, which promoted fatty acid oxidation in palmitate-treated HepG2 cells. Overall, 8PG acts as a potent AMPK activator, further attenuating hepatic steatosis via the SIRT1-mediated pathway and providing new avenues for dietary interventions to treat metabolic dysfunction-associated steatotic liver disease (MASLD). [ABSTRACT FROM AUTHOR]

Diabetic cardiomyopathy (DCM) is a prevalent complication of diabetes mellitus characterized by cardiac dysfunction and myocardial remodeling. Farrerol (FA), an active ingredient in Rhododendron with various pharmacological activities, has an unclear specific role in DCM. Therefore, this study aims to investigate the effects of FA on DCM rats and elucidate its mechanism. The type 2 diabetes mellitus (T2DM) model was induced in adult male Sprague-Dawley rats by administering a high-fat diet for 8 weeks along with STZ injection. Subsequent to successful modeling, FA and the positive drug Dapagliflozin (Dapa) were orally administered via gavage for an additional 8-week period. After administration, the rats' body weight, fasting blood glucose, fasting insulin, and blood lipid profiles were quantified. Cardiac function was assessed through evaluation of cardiac function parameters, histopathological examination and measurement of myocardial enzyme markers were conducted to assess myocardial injury and fibrosis, Oil red O staining was utilized to evaluate myocardial lipid accumulation, wheat germ agglutinin (WGA) staining was used for assessing cardiomyocyte hypertrophy, and Western blot analysis was used to detect the proteins expression level of AMP-activated protein kinase (AMPK) pathway. The rat cardiomyocyte H9c2 were induced with palmitic acid to establish an in vitro cell model of myocardial lipid toxicity. Subsequently, the cells were subjected to treatment with FA and AMPK inhibitor Compound C, followed by assessment of lipid formation and expression levels of proteins related to the AMPK signaling pathway. The findings demonstrated that both FA and Dapa exhibited efficacy in ameliorating diabetic symptoms, cardiac dysfunction, myocardial fibrosis, cardiomyocyte hypertrophy, and lipid accumulation in T2DM rats. Additionally, they were found to enhance AMPK phosphorylation and PPARα expression while down-regulating CD36. Similarly, FA was observed to inhibit lipid formation in H9c2 and activate the AMPK signaling pathway. However, the improved effect of FA on lipotoxic cardiomyocytes induced by palmitic acid was partially reversed by Compound C. Therefore, the activation of the AMPK signaling pathway by FA may enhance cardiac lipid metabolism, thereby improving cardiac dysfunction and myocardial fibrosis in DCM rats. [ABSTRACT FROM AUTHOR]

Hypertension is a globally prevalent disease, but the pathogenesis remains largely unclear. AMP-activated protein kinase (AMPK) is a nutrition-sensitive signal of cellular energy metabolism, which has a certain influence on the development of hypertension. Previously, we found a down-regulation of the phosphorylated (p-) form of AMPK, and the up-regulation of the angiotensin II type 1 receptor (AT1-R) and that of p-ERK1/2 in the hypothalamic paraventricular nucleus (PVN) of hypertensive rats. However, the exact mechanism underlying the relationship between AMPK and AT1-R in the PVN during hypertension remains unclear. Thus, we hypothesized that AMPK modulates AT1-R through the ERK1/2-NF-κB pathway in the PVN, thereby inhibiting sympathetic nerve activity and improving hypertension. To examine this hypothesis, we employed a renovascular hypertensive animal model developed via two-kidney, one-clip (2K1C) and sham-operated (SHAM). Artificial cerebrospinal fluid (aCSF), used as vehicle, or 5-amino-1-β-d-ribofuranosyl-imidazole-4-carboxamide (AICAR, an AMPK activator, 60 μg/day) was microinjected bilaterally in the PVN of these rats for 4 weeks. In 2K1C rats, there an increase in systolic blood pressure (SBP) and circulating norepinephrine (NE). Also, the hypertensive rats had lowered expression of p-AMPK and p-AMPK/AMPK, elevated expression of p-ERK1/2, p-ERK1/2/ERK1/2 and AT1-R, increased NF-κB p65 activity in the PVN compared with the levels of these biomarkers in SHAM rats. Four weeks of bilateral PVN injection of AMPK activator AICAR, attenuated the NE level and SBP, increased the expression of p-AMPK and p-AMPK/AMPK, lessened the NF-κB p65 activity, decreased the expression of p-ERK1/2, p-ERK1/2/ERK1/2 and AT1-R in the PVN of 2K1C rats. Data from this study imply that the activation of AMPK within the PVN suppressed AT1-R expression through inhibiting the ERK1/2-NF-κB pathway, decreased the activity of the sympathetic nervous system, improved hypertension. [ABSTRACT FROM AUTHOR]

AMP-activated protein kinase (AMPK) dysregulation is implicated in osteoarthritis (OA), but the mechanisms underlying this dysregulation remain unclear. We investigated the role of cereblon, a substrate-recognition protein within the E3-ligase ubiquitin complex, in AMPK dysregulation and OA pathogenesis. Cereblon expression was examined in human (n = 5) and mouse (n = 10) OA cartilage. The role of cereblon was investigated through its adenoviral overexpression (n = 10) or knockout (KO, n = 15) in the destabilization of the medial meniscus (DMM)-operated mice. The therapeutic potentials of the chemical cereblon degrader, TD-165, and the AMPK activator, metformin, were assessed through intra-articular (IA) injection to mice (n = 15). Immunostaining revealed that cereblon is upregulated in human and mouse OA cartilage. In DMM model mice, cartilage destruction was exacerbated by overexpression of cereblon in mouse joint tissues (OARSI grade; 1.11 [95% CI: 0.50 to 2.75]), but inhibited in global (−2.50 [95% CI: −3.00 to −1.17]) and chondrocyte-specific (−2.17 [95% CI: −3.14 to −1.06]) cereblon KO mice. The inhibitory effects were more pronounced in mice fed a high-fat diet compared to a regular diet. The degradation of cereblon through IA injection of TD-165 inhibited OA cartilage destruction (−2.47 [95% CI: −3.22 to −1.56]). Mechanistically, cereblon exerts its catabolic effects by negatively modulating AMPK activity within chondrocytes. Consistently, activation of AMPK by IA injection of metformin inhibited posttraumatic OA cartilage destruction (−1.20 ([95% CI: −1.89 to −0.45]). The cereblon-AMPK axis acts as a catabolic regulator of OA pathogenesis and seems to be a promising therapeutic target in animal models of OA. [ABSTRACT FROM AUTHOR]

Abstract Background The fruit of Phyllanthus emblica L., a traditional medicine in China and India, is used to treat diabetes mellitus. Its water extract (WEPE) has demonstrated hypoglycemic effects in diabetic rats, but its mechanisms on glucose utilization and insulin resistance in skeletal muscle remain unclear. Therefore, this study aims to investigate the effects and underlying mechanisms of WEPE on glucose utilization and insulin resistance using C2C12 myotubes. Methods Effects of WEPE on glucose uptake, GLUT4 translocation, and AMPK and AKT phosphorylation were investigated in C2C12 myotubes and palmitate-treated myotubes. An AMPK inhibitor and siRNA were used to explore the mechanisms of WEPE. Glucose uptake was determined using a 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino)-2-deoxyglucose (2-NBDG) uptake assay, and protein expression and GLUT4 translocation were assessed via western blotting. Results In normal myotubes, WEPE significantly stimulated glucose uptake and GLUT4 translocation to the plasma membrane at concentrations of 125 and 250 µg/mL. This was accompanied by an increase in the phosphorylation of AMPK and its downstream targets. However, both compound C and AMPK siRNA blocked the WEPE-induced GLUT4 translocation and glucose uptake. Moreover, pretreatment with STO-609, a calcium/calmodulin-dependent protein kinase kinase β (CaMKKβ) inhibitor, inhibited WEPE-induced AMPK phosphorylation and attenuated the WEPE-stimulated glucose uptake and GLUT4 translocation. In myotubes treated with palmitate, WEPE prevented palmitate-induced insulin resistance by enhancing insulin-mediated glucose uptake and AKT phosphorylation. It also restored the insulin-mediated translocation of GLUT4 from cytoplasm to membrane. However, these effects of WEPE on glucose uptake and GLUT4 translocation were blocked by pretreatment with compound C. Conclusions WEPE significantly stimulated basal glucose uptake though CaMKKβ/AMPK pathway and markedly ameliorated palmitate-induced insulin resistance by activating the AMPK pathway in C2C12 myotubes.

Objective To observe the effect of total flavonoids of Dracocephalum Moldavica L. on bleomycin-induced pulmonary fibrosis （PF) in rats and to explore the possible mechanism based on intestinal flora and serum metabolomics approaches. Methods Thirty-two male SD rats were randomly divided into the control group， model group， high dose total flavonoids of Dracocephalum Moldavica L. group and low-dose total flavonoids of Dracocephalum Moldavica L. group， with 8 rats in each group. In addition to the control group， the model was established by intratracheal drip of bleo‑ mycin in each group；400 mg/kg and 100 mg/kg of total flavonoids of Dracocephalum Moldavica L. were given by gavage in the high- and low-dose groups， respectively， and an equal volume of normal saline was given by gavage in the control group and the model group， respectively， once a day for 21 d. The lung histopathology was observed by HE and Masson staining. The collagen Ⅲ（COLⅢ) and α-smooth muscle actin （α-SMA) mRNA expression levels in the lung tissues were detected by real-time fluorescence quantitative PCR. 16S rRNA sequencing technology was used to detect the diversity and relative abundance of intestinal flora， and ultra-high-performance liquid chromatography-tandem mass spectrometry （UPLC-MS/MS) was used to analyse and screen for the key differential metabolites in serum， which were then imported into the Kyoto Encyclopedia of Genes and Genomes （KEGG) for the metabolic pathway enrichment analysis. Results Com‑ pared with the control group， the alveolar structure of rats in the model group was destroyed， the alveolar intervals were widened， the inflammatory cell infiltration was obvious， the alveolar wall was thickened， the distance between the alveoli was widened， and the deposition of collagen fibres in blue stripes was seen； compared with the model group， the above pathological changes were reduced in rats in the high- and low-dose total flavonoids of Dracocephalum Moldavica L. groups. Compared with the control group， the relative expression levels of COLⅢ and α-SMA mRNA in the lung tissues of rats in the model group increased （all P<0. 05)； compared with the model group， the relative expression levels of COLⅢ and α-SMA mRNA in the lung tissues of rats in the high- and low-dose total flavonoids of Dracocephalum Moldavica L. groups decreased （all P<0. 05). Analysis of α-diversity showed that， compared with the control group， the model group， the intestinal flora Chao1 and Ace increased in the high-dose and low-dose total flavonoids of Dracocephalum Moldavica L. groups （all P<0. 05). The β-diversity analysis showed that the composition of the intestinal flora of the rats in the control group， the high-dose and low-dose total flavonoids of Dracocephalum Moldavica L. groups were close to each other， and that was different from the composition of the intestinal flora of the rats in the model group. At the phylum level， compared with the control group， the relative abundance of Bacteroidota decreased， while the abundances of Firmicutes/Bacteroidota increased in rats of the model group （all P<0. 05)； compared with the model group， the relative abundance of Bacteroidota in rats in the high- and low-dose total flavonoids of Dracocephalum Moldavica L. groups increased， while the relative abun‑ dances of Firmicutes/Bacteroidota decreased （all P<0. 05). At the genus level， compared with the control group， the rela‑ tive abundances of Ligilactobacillus decreased in the remaining three groups （all P<0. 05)； compared with the control and model groups， the relative abundances of Lactobacillus increased in the high- and low-dose total flavonoids of Dracoceph‑ alum Moldavica L. groups （all P<0. 05). Compared with the control group， the key differential flora of rats in the model group was Escherichia coli species； compared with the model group， the key differential floras of rats in the high-dose total flavonoids of Dracocephalum Moldavica L. group were Bifidobacterium pseudo-longum， Bifidobacterium bifidum， and Ru‑ minococcus； compared with the model group， the key differential floras of rats in the low-dose total flavonoids of Draco‑ cephalum Moldavica L. group were Lactobacillus johannesiensis and Akkermansia muciniphila. Thirty and forty-nine se‑ rum differential metabolites were screened out between the model group and the high- and low-dose total flavonoids of Dracocephalum Moldavica L. groups， all of which were mainly enriched in the AMP-activated protein kinase （AMPK) sig‑ naling pathway， etc. Conclusion Total flavonoids of Dracocephalum Moldavica L. attenuate bleomycin-induced PF in rats， and the mechanism of action may be related to regulating the composition of intestinal flora and AMPK-related meta‑ bolic pathways， etc. [ABSTRACT FROM AUTHOR]

Metabolic dysfunction‐associated steatotic liver disease (MASLD) is strongly associated with insulin resistance development. Hepatic lipid accumulation and inflammation are considered the main drivers of hepatic insulin resistance in MASLD. Cysteine‐rich 61 (Cyr61 also called CCN1), a novel secretory matricellular protein, is implicated in liver inflammation, and its role in MASLD is not clearly understood. Therefore, we investigated the role of Cyr61 in hepatic insulin resistance and lipid metabolism as major factors in MASLD pathogenesis. In high‐fat diet (HFD)‐fed C57BL/6J mice, Cyr61 was downregulated or upregulated via viral transduction. Measurements of glucose homeostasis, histological assessment of liver tissues, and gene expression and signaling pathways of lipogenesis, fatty acid oxidation, and inflammation were performed using liver samples from these mice. Cyr61 levels in HepG2 cells were reduced using RNAi‐mediated gene knockdown. Inflammation and insulin resistance were evaluated using real‐time polymerase chain reaction and western blotting. HFD/AAV‐shCyr61 mice exhibited enhanced glucose tolerance via the protein kinase B pathway, reduced hepatic inflammation, decreased lipogenesis, and increased fatty acid oxidation. Notably, HFD/AAV‐shCyr61 mice showed elevated protein expression of sirtuin 6 and phosphorylated‐AMP‐activated protein kinase. In vitro experiments demonstrated that inhibition of Cyr61 downregulated pro‐inflammatory cytokines such as interleukin‐1 beta, IL‐6, and tumor necrosis factor‐alpha via the nuclear factor kappa B/c‐Jun N‐terminal kinase pathway, and alleviated insulin resistance. Cyr61 affected hepatic inflammation, lipid metabolism, and insulin resistance. Inhibition of Cyr61 reduced inflammation, recovered insulin resistance, and altered lipid metabolism in vivo and in vitro. Therefore, Cyr61 is a potential therapeutic target in MASLD. [ABSTRACT FROM AUTHOR]

Obesity is one of the more complicated diseases, it can induce numerous life‐threatening diseases mainly diabetes mellitus, cardiovascular disease, hypertension, and certain cancers. In this study, we assessed the efficacy of bacoside‐A (a dammarane‐type triterpenoid saponin derived from the plant Bacopa monniera Linn.) on the adipogenesis of 3T3‐L1 preadipocytes. Results of this study illustrated that bacoside‐A decreased the differentiation of 3T3‐L1 cell, as evidenced by diminution of lipid droplets, which contains triglycerides and other lipids. During the differentiation process, transcription factors, which are mainly participating in adipogenesis such us CCAAT/enhancer‐binding protein α (C/EBPα) and C/EBPβ, peroxisome proliferator‐activated receptor‐γ (PPARγ), and sterol regulatory element‐binding protein‐1c (SREBP‐1c), expressions were significantly suppressed by bacoside‐A. In addition, bacoside‐A showed a potent reduction in genes precise to adipocytes such as lipoprotein lipase (LPL), fatty acid synthase (FAS), adipocyte fatty acid‐binding protein (FABP4), and leptin expressions. Further, bacoside‐A stimulated the phosphorylation of acetyl CoA carboxylase (ACC) and AMP‐activated protein kinase (AMPK). These results demonstrated that bacoside‐A has anti‐adipogenic effects by regulating the transcription factors involved in adipocyte differentiation. Therefore, bacoside‐A might be considered as a potent therapeutic agent for alleviating obesity and hyperlipidemia. [ABSTRACT FROM AUTHOR]

Background: The fruit of Phyllanthus emblica L., a traditional medicine in China and India, is used to treat diabetes mellitus. Its water extract (WEPE) has demonstrated hypoglycemic effects in diabetic rats, but its mechanisms on glucose utilization and insulin resistance in skeletal muscle remain unclear. Therefore, this study aims to investigate the effects and underlying mechanisms of WEPE on glucose utilization and insulin resistance using C2C12 myotubes. Methods: Effects of WEPE on glucose uptake, GLUT4 translocation, and AMPK and AKT phosphorylation were investigated in C2C12 myotubes and palmitate-treated myotubes. An AMPK inhibitor and siRNA were used to explore the mechanisms of WEPE. Glucose uptake was determined using a 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino)-2-deoxyglucose (2-NBDG) uptake assay, and protein expression and GLUT4 translocation were assessed via western blotting. Results: In normal myotubes, WEPE significantly stimulated glucose uptake and GLUT4 translocation to the plasma membrane at concentrations of 125 and 250 µg/mL. This was accompanied by an increase in the phosphorylation of AMPK and its downstream targets. However, both compound C and AMPK siRNA blocked the WEPE-induced GLUT4 translocation and glucose uptake. Moreover, pretreatment with STO-609, a calcium/calmodulin-dependent protein kinase kinase β (CaMKKβ) inhibitor, inhibited WEPE-induced AMPK phosphorylation and attenuated the WEPE-stimulated glucose uptake and GLUT4 translocation. In myotubes treated with palmitate, WEPE prevented palmitate-induced insulin resistance by enhancing insulin-mediated glucose uptake and AKT phosphorylation. It also restored the insulin-mediated translocation of GLUT4 from cytoplasm to membrane. However, these effects of WEPE on glucose uptake and GLUT4 translocation were blocked by pretreatment with compound C. Conclusions: WEPE significantly stimulated basal glucose uptake though CaMKKβ/AMPK pathway and markedly ameliorated palmitate-induced insulin resistance by activating the AMPK pathway in C2C12 myotubes. [ABSTRACT FROM AUTHOR]

Recently, the incidence of NAFLD has exploded globally, but there are currently no officially approved medications for treating the condition. The regulation of NAFLD through plant-derived active substances has become a new area of interest. Quinoa (Chenopodium quinoa Willd.) has been discovered to contain a large quantity of bioactive compounds. In this study, we established a free fatty acid (FFA)-induced steatosis model and explored the effects of quinoa polyphenol extract (QPE) on the major hallmarks of NAFLD. The results indicated that QPE significantly reduced intracellular triglyceride (TG) and total cholesterol (TC) levels. Additionally, QPE remarkably elevated the levels of superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH) and lowered levels of malondialdehyde (MDA). Further examination revealed that QPE attenuated intracellular inflammation, which was verified by the reduced levels of pro-inflammatory cytokines. Mechanistically, QPE inhibited fatty acid biosynthesis mainly by targeting de novo lipogenesis (DNL) via the AMPK/SREBP-1c signaling pathway. Moreover, network pharmacology was used to analyze key targets for NAFLD mitigation by ferulic acid (FA), a major component of QPE. Taken together, this study suggests that QPE could ameliorate NAFLD by modulating hepatic lipid metabolism and alleviating oxidative stress and inflammation. [ABSTRACT FROM AUTHOR]

Neuropathic pain is a chronic pain condition caused by damage or dysfunction of the nervous system. Symptoms of neuropathic pain include spontaneous pain, hyperalgesia, and sensory abnormalities. AMP-activated protein kinase (AMPK) is a key energy regulator that maintains cellular homeostasis by modulating carbohydrate and lipid metabolism. Recent studies have highlighted its role in synaptic plasticity and glial cell function, suggesting that AMPK signaling pathways contribute to the onset and progression of neurological disorders. Investigations using animal models of neuropathic pain as well as clinical research have illustrated aberrations in AMPK expression and activity at various sites along sensory conduction pathways. Treatment with AMPK agonists has been shown to alleviate pain symptoms, suggesting that dysregulation of AMPK expression/function contributes to the development and persistence of neuropathic pain. Therefore, the development of analgesics targeting AMPK has garnered considerable attention worldwide. This article provides a comprehensive review of the mechanisms by which AMPK participates in neuropathic pain, with the aim of guiding the development of related analgesic drugs. [ABSTRACT FROM AUTHOR]

Obesity has become a major risk of global public health. SMEK1 is also known as a regulatory subunit of protein phosphatase 4 (PP4). Both PP4 and SMEK1 have been clarified in many metabolic functions, including the regulation of hepatic gluconeogenesis and glucose transporter gene expression in yeast. Whether SMEK1 participates in obesity and the broader metabolic role in mammals is unknown. Thus, we investigated the function of SMEK1 in white adipose tissue and glucose uptake. GWAS/GEPIA/GEO database was used to analyze the correlation between SMEK1 and metabolic phenotypes/lipid metabolism-related genes/obesity. Smek1 KO mice were generated to identify the role of SMEK1 in obesity and glucose homeostasis. Cell culture and differentiation of stromal-vascular fractions (SVFs) and 3T3-L1 were used to determine the mechanism. 2-NBDG was used to measure the glucose uptake. Compound C was used to confirm the role of AMPK. We elucidated that SMEK1 was correlated with obesity and adipogenesis. Smek1 deletion enhanced adipogenesis in both SVFs and 3T3-L1. Smek1 KO protected mice from obesity and had protective effects on metabolic disorders, including insulin resistance and inflammation. Smek1 KO mice had lower levels of fasting serum glucose. We found that SMEK1 ablation promoted glucose uptake by increasing p-AMPKα(T172) and the transcription of Glut4 when the effect on AMPK-regulated glucose uptake was due to the PP4 catalytic subunits (PPP4C). Our findings reveal a novel role of SMEK1 in obesity and glucose homeostasis, providing a potential new therapeutic target for obesity and metabolic dysfunction. NEW & NOTEWORTHY: Our study clarified the relationship between SMEK1 and obesity for the first time and validated the conclusion in multiple ways by combining available data from public databases, human samples, and animal models. In addition, we clarified the role of SMEK1 in glucose uptake, providing an in-depth interpretation for the study of its function in glucose metabolism. [ABSTRACT FROM AUTHOR]

IntroductionEmerging evidences suggests that the disrupted branched-chain amino acids (BCAAs) homeostasis and elevated BCAAs promote obesity-related insulin resistance (IR). Exercise improves insulin sensitivity. However, whether BCAAs plays a role in the exercise-attenuated IR remains to be fully investigated.MethodsIn this study, male C57BL/6J mice were induced to become diet-induced obese (DIO) and served as subjects. The initial investigation focused on the impact of exercise on IR and BCAAs. The DIO mice were randomly assigned to either a sedentary group (CON, n = 16) or an exercise group (EX, n = 16). The EX group underwent a 12-week aerobic exercise regimen on a treadmill. After 12-week, plasma BCAAs and branched-chain keto acids (BCKAs) were measured by liquid chromatography-mass spectrometry, glucose tolerance test (GTT) and insulin tolerance test (ITT) were performed, and the expression and phosphorylation of BCAAs catabolic proteins, as well as AKT T308 in gastrocnemius muscle and liver tissues, were evaluated using western blotting. Subsequently, the study explored the role of BCAAs in enhancing IR through exercise. Mice were randomly allocated into 4 groups: sedentary group (CON, n = 8), sedentary with BCAAs supplementation group (CON+BCAA, n = 8), exercise group (EX, n = 16), and exercise with BCAAs supplementation group (EX+BCAA, n = 16). The exercise protocol was as above. Mice in the BCAAs supplemented groups received drinking water containing 2% BCAAs. After 12-week, plasma BCAAs and BCKAs were measured, GTT and ITT tests were performed, and the phosphorylation of AKT T308, as well as p70S6K T389 in gastrocnemius muscle and liver, were compared between the EX group and the EX+BCAA group. Additionally, the phosphorylation of AMPKα T172 in both tissues was measured across all four groups.Results12-week aerobic exercise improved insulin sensitivity in DIO mice while inducing BCAAs catabolic protein expression in skeletal muscle and liver, and reducing the plasma BCAAs level. Importantly, BCAAs supplementation elevated the plasma level of BCAAs and counteracted the exercise-attenuated IR. In skeletal muscle and liver tissues, BCAAs supplementation impaired the exercise-improved insulin signaling without enhancing mammalian target of rapamycin activity. AMPK activity was enhanced by aerobic exercise, which was abolished by BCAAs supplementation.ConclusionAerobic exercise attenuated insulin resistance via restoring BCAAs homeostasis and AMPK activity. The impacts of BCAAs intake on the metabolic effects of exercise sheds light on the combined exercise and nutrition intervention strategy for diabetes management.

Glucose metabolism disturbances may result in diabetes-associated cognitive decline (DACI). Methionine restriction (MR) diet has emerged as a potential dietary strategy for managing glucose homeostasis. However, the effects and underlying mechanisms of MR on DACI have not been fully elucidated. Here, we found that a 13-week MR (0.17 % methionine, w/w) intervention starting at 8 weeks of age improved peripheral insulin sensitivity in male db/db mice, a model for type 2 diabetes. Notably, MR significantly improved working as well as long-term memory in db/db mice, accompanied by increased PSD-95 level and reduced neuroinflammatory factors, malondialdehyde (MDA), and 8-hydroxy-2′-deoxyguanosine (8-OHdG). We speculate that this effect may be mediated by MR activating hepatic fibroblast growth factor 21 (FGF21) and the brain FGFR1/AMPK/GLUT4 signaling pathway to enhance brain glucose metabolism. To further delineate the mechanism, we used intracerebroventricular injection of adeno-associated virus to specifically knock down FGFR1 in the brain to verify the role of FGFR1 in MR-mediated DACI. It was found that the positive effects of MR on DACI were offset, reflected in decreased cognitive function, impaired synaptic plasticity, upregulated neuroinflammation, and balanced enzymes regulating reactive oxygen species (Sod1, Sod2, Nox4). Of note, the FGFR1/AMPK/GLUT4 signaling pathway and brain glucose metabolism were inhibited. In summary, our study demonstrated that MR increased peripheral insulin sensitivity, activated brain FGFR1/AMPK/GLUT4 signaling through FGF21, maintained normal glucose metabolism and redox balance in the brain, and thereby alleviated DACI. These results provide new insights into the effects of MR diet on cognitive dysfunction caused by impaired brain energy metabolism.

Abstract Background Small‐cell lung cancer (SCLC) shows high enhancer of zeste homolog 2 (EZH2) expressions. EZH2‐mediated epigenetics promote epithelial‐mesenchymal transition (EMT), enhancing invasive and metastatic potential in malignancies. MicroRNAs (miRNAs), small noncoding RNAs, modulate EMT, determining tumor phenotypes. However, the association between miRNAs and EZH2 in SCLC remains to be clarified—we aimed to identify a novel tumorigenic mechanism through miRNAs, EZH2, and EMT in SCLC, leading to future therapeutic applications. Methods We analyzed EZH2 and E‐cadherin expressions in lung cancer cell lines and tumor tissues from 34 SCLC patients and confirmed EZH2 siRNA‐mediated EMT inhibition. miRNA expression profiles were compared between EZH2 knockdown SCLC cells and negative control SCLC cells using miRNA array. We identified a target miRNA of EZH2 showing expressional differences in EZH2‐knockdown cells and analyzed the impact of the miRNA on EZH2‐mediated EMT and tumorigenesis. Results All SCLC cells showed increased EZH2 and decreased E‐cadherin expressions. SCLC tissues had higher EZH2 and lower E‐cadherin expressions than other lung cancer tissues. miRNA array revealed that miR‐4448 expression increased in EZH2‐knockdown SCLC cells. miR‐4448 overexpression reduced tumor cell growth and prevented EMT. miR‐4448 bound to the 3′UTR of the girdin gene and suppressed its expression, thereby decreasing Akt phosphorylation at Ser473. Attenuated Akt phosphorylation resulted in AMP‐activated protein kinase (AMPK) phosphorylation at Thr172 and 183, enhancing EZH2 phosphorylation at Thr311. Conclusion SCLC characterized high EZH2 expression and promoted EMT, compared with non‐small cell lung cancer. miR‐4448 inhibited Girdin expression, reducing Akt phosphorylation, and enhancing AMPK and EZH2 phosphorylation. Eventually, miR‐4448 prevented EZH2‐mediated EMT and tumorigenesis by modulating the Girdin/Akt/AMPK axis in SCLC. miR‐4448 might be a potential SCLC inhibitor.

Promotion of brown adipose tissue phenotype, able to transform energy into heat, is a promising target against obesity development. We investigated the effects of a standardized extract from Cynara cardunculus L. (CCLE) leaves, considered a waste food resource, on adipogenesis inhibition in 3T3-L1 cells, through the thermogenic process involvement. CCLE inhibited adipogenesis (C/EBPβ, PPAR-γ, FABP4, SREBP-1, and FASN) and increased thermogenesis via upregulation of AMPK phosphorylation. Furthermore, CCLE induced FOXO1 pathway as adipogenesis repressive mechanism affecting PPAR-γ activity and induced the expression of cell cycle inhibitor p21. However, pretreatment with the AMPK inhibitor compound C abolished CCLE effects on FOXO1, p21, C/EBPβ, and PPAR-γ. These data confirmed that the antiadipogenic effect of the extract is related to AMPK activation. Therefore, this work provides new perspectives for the use of this extract in obesity prevention and management. Additionally, reuse/recycling of waste food resources provides added value from a circular economy perspective.

Abstract Background Energy metabolism disorders and neurogenic inflammation play important roles in the central sensitization to chronic migraine (CM). AMP-activated protein kinase (AMPK) is an intracellular energy sensor, and its activation regulates inflammation and reduces neuropathic pain. However, studies on the involvement of AMPK in the regulation of CM are currently lacking. Therefore, this study aimed to explore the mechanism underlying the involvement of AMPK in the central sensitization to CM. Methods Mice with recurrent nitroglycerin (NTG)-induced CM were used to detect the expression of AMPK protein in the trigeminal nucleus caudalis (TNC). Following intraperitoneal injection of the AMPK activator 5-aminoimidazole-4-carboxyamide ribonucleoside (AICAR) and inhibitor compound C, the mechanical pain threshold, activity level, and pain-like behaviors in the mice were measured. The expression of calcitonin gene-related peptide (CGRP) and cytokines, M1/M2 microglia, and NF-κB pathway activation were detected after the intervention. Results Repeated NTG injections resulted in a gradual decrease in AMPK protein expression, and the negative regulation of AMPK by increased ubiquitin-like plant homeodomain and RING finger domain 1 (UHRF1) expression may counteract AMPK activation by increasing ADP/ATP. AICAR can reduce the hyperalgesia and pain-like behaviors of CM mice, improve the activity of mice, reduce the expression of CGRP, IL-1β, IL-6, and TNF-α in the TNC region, and increase the expression of IL-4 and IL-10. Moreover, AMPK in TNC was mainly located in microglia. AICAR could reduce the expression of inducible NO synthase (iNOS) in M1 microglia and increase the expression of Arginase 1 (Arg1) in M2 microglia by inhibiting the activation of NF-κB pathway. Conclusions AMPK was involved in the central sensitization of CM, and the activation of AMPK reduced neuroinflammation in NTG-induced CM mice. AMPK may provide new insights into interventions for energy metabolism disorders and neurogenic inflammation in migraine.

mTORC1 senses nutrients and growth factors and phosphorylates downstream targets, including the transcription factor TFEB, to coordinate metabolic supply and demand. These functions position mTORC1 as a central controller of cellular homeostasis, but the behavior of this system in individual cells has not been well characterized. Here, we provide measurements necessary to refine quantitative models for mTORC1 as a metabolic controller. We developed a series of fluorescent protein-TFEB fusions and a multiplexed immunofluorescence approach to investigate how combinations of stimuli jointly regulate mTORC1 signaling at the single-cell level. Live imaging of individual MCF10A cells confirmed that mTORC1-TFEB signaling responds continuously to individual, sequential, or simultaneous treatment with amino acids and the growth factor insulin. Under physiologically relevant concentrations of amino acids, we observe correlated fluctuations in TFEB, AMPK, and AKT signaling that indicate continuous activity adjustments to nutrient availability. Using partial least squares regression modeling, we show that these continuous gradations are connected to protein synthesis rate via a distributed network of mTORC1 effectors, providing quantitative support for the qualitative model of mTORC1 as a homeostatic controller and clarifying its functional behavior within individual cells.

Multiple sclerosis (MS) is a chronic central nervous system (CNS) disorder characterized by demyelination, neuronal damage, and oligodendrocyte depletion. Reliable biomarkers are essential for early diagnosis and disease management. Emerging research highlights the role of mitochondrial dysfunction and oxidative stress in CNS disorders, including MS, in which mitochondria are central to the degenerative process. Adenosine monophosphate‐activated protein kinase (AMPK) regulates the mitochondrial energy balance and initiates responses in neurodegenerative conditions. This systematic review, following Preferred Reporting Items for Systematic Reviews and Meta‐Analyses guidelines, aimed to comprehensively assess the literature on AMPK pathways, mitochondrial dysfunction, and in vivo studies using MS animal models. The search strategy involved the use of AMPK syntaxes, MS syntaxes, and animal model syntaxes. The PubMed, Scopus, Web of Science, and Google Scholar databases were systematically searched on August 26, 2023 without publication year restrictions. The review identified and analyzed relevant papers to provide a comprehensive overview of the current state of related research. Eight studies utilizing various interventions and methodological approaches were included. Risk of bias assessment revealed some areas of low risk but lacked explicit reporting in others. These studies collectively revealed a complex relationship between AMPK, mitochondrial dysfunction, and MS pathogenesis, with both cuprizone and experimental autoimmune encephalomyelitis models demonstrating associations between AMPK and mitochondrial disorders, including oxidative stress and impaired expression of mitochondrial genes. These studies illuminate the multifaceted role of AMPK in MS animal models, involving energy metabolism, inflammatory processes, oxidative stress, and gene regulation leading to mitochondrial dysfunction. However, unanswered questions about its mechanisms and clinical applications underscore the need for further research to fully harness its potential in addressing MS‐related mitochondrial dysfunction. [ABSTRACT FROM AUTHOR]

AIM: To comprehend the mechanism by which ginsenoside Rc protects against cerebral ischemiareperfusion injury (CIRI), with a particular emphasis on pyroptosis. METHODS: The C57BL/6 mice were randomly divided into 6 groups: sham group, middle cerebral artery occlusion/reperfusion (MCAO/R) group, ginsenoside Rc+MCAO/ R group (Rc group), AMP-activated protein kinase (AMPK) agonist acadesine/5-aminoimidazole-4-carboxamide-1-β-Dribofuranoside (AICAR)+MCAO/R group (agonist group), and ginsenoside Rc+MCAO/R+AMPK inhibitor Compound C group (Rc+inhibitor group). The mice in agonist group were given 500 mg/kg of AICAR intraperitoneally, while those in Rc+inhibitor group were given 20 mg/kg of Compound C intraperitoneally. Ginsenoside Rc was gavaged into the mice in Rc and Rc+inhibitor groups at a dose of 40 mg/kg once per day for 7 d after modeling, while the mice in sham and MCAO/ R groups got the same volume of purified water. With the use of the Zea-Longa score, we determined which mice had neurological abnormalities. TTC staining was employed for assessing the cerebral infarct amount in mice, and the dry wet weight technique was utilized for determining the degree of cerebral edema. Moreover, HE staining was used to observe pathological alterations in the brain, and Western blot and RT-qPCR were applied for detecting the expression of AMPK, nucleotide-binding oligomerization domain-like receptor protein 3(NLRP3), caspase-1 and gasdermin-D (GSDMD) in the brains of mice. Lastly, ELISA was employed for measuring the levels of inflammatory factors, interleukin-1β(IL-1β) and IL-18. RESULTS: Brain edema, infarct volume and neurological impairments were all diminished in agonist and Rc groups. Additionally, they demonstrated neuronal damage inhibition. The ratio of p-AMPK/AMPK and AMPK mRNA expression in mouse brain tissues was elevated in both Rc and agonist groups. They showed decreased mRNA and protein levels of NLRP3, caspase-1 and GSDMD, as well as the levels of IL-1β and IL-18. Compared with Rc group, there were remarkable decreases in p-AMPK/AMPK ratio and AMPK mRNA expression in the brain tissue of mice in Rc+inhibitor group (P<0. 05). The mRNA and protein levels of NLRP3, caspase-1 and GSDMD, and the IL-1β and IL-18 expression levels were significantly increased (P<0. 05). Moreover, the neurological deficiency scores and infarct volume were increased, and the degrees of cerebral edema and neuronal pathological damage were enhanced (P<0. 05). CONCLUSION: Ginsenoside Rc may inhibit NLRP3/caspase-1/GSDMD-mediated pyroptosis by activating AMPK pathway, thereby reducing CIRI in mice. [ABSTRACT FROM AUTHOR]

Kimchi is a traditional fermented food that contains abundant nutrients and functional ingredients with various health benefits. We previously reported that kimchi active components suppress hepatic steatosis caused by endoplasmic reticulum (ER) stress in vitro and in vivo. Therefore, we assessed the effect of kimchi on the inhibition of hepatic steatosis caused by ER stress in HepG2 cells and C57BL/6N mice to verify the hypothesis that kimchi may potentially inhibit nonalcoholic fatty liver disease. We investigated the effect of kimchi on cell viability and triglyceride concentrations in cells and on lipid profile, lipid accumulation, and expression of related genes in cells and mice with hepatic steatosis. A mechanistic study was also performed using the liver X receptor α agonist T0901317 and the AMP-activated protein kinase agonist AICAR. Kimchi was noncytotoxic and effectively reduced triglyceride concentrations and suppressed hepatic steatosis-related gene expression in cells and mice. Additionally, kimchi recovered weight loss, lowered the serum and liver tissue lipid profiles, suppressed lipid accumulation, and reduced the effects of T0901317 and AICAR on lipogenic gene expression in tunicamycin-treated mice. Our results highlight that kimchi could prevent hepatic steatosis caused by ER stress in cells and mice. ER stress commonly causes hepatic steatosis in vitro and in vivo. In this study, kimchi attenuated ER stress–induced hepatic steatosis in HepG2 cells and C57BL/6N mice. Kimchi inhibited hepatic steatosis by regulating the LXRα/AMPK pathway. Abbreviations: ACC, acetyl coenzyme-A carboxylase; AMPK, AMP-activated protein kinase; ER, endoplasmic reticulum; FAS, fatty acid synthase; GOT, oxaloacetic transaminase; GPT, glutamic pyruvic transaminase; H&E, hematoxylin and eosin; ORO, oil red O; LXRα, liver X receptor α; SCD-1, stearoyl-CoA desaturase-1; SREBP-1c, sterol regulatory element-binding transcription factor 1c. [Display omitted] [ABSTRACT FROM AUTHOR]

Interleukin‐38 (IL‐38), recently recognized as a cytokine with anti‐inflammatory properties that mitigate type 2 diabetes, has been associated with indicators of insulin resistance and nonalcoholic fatty liver disease (NAFLD). This study investigated the impact of IL‐38 on hepatic lipid metabolism and endoplasmic reticulum (ER) stress. We assessed protein expression levels using Western blot analysis, while monodansylcadaverine staining was employed to detect autophagosomes in hepatocytes. Oil red O staining was utilized to examine lipid deposition. The study revealed elevated serum IL‐38 levels in high‐fat diet (HFD)‐fed mice and IL‐38 secretion from mouse keratinocytes. IL‐38 treatment attenuated lipogenic lipid accumulation and ER stress markers in hepatocytes exposed to palmitate. Furthermore, IL‐38 treatment increased AMP‐activated protein kinase (AMPK) phosphorylation and autophagy. The effects of IL‐38 on lipogenic lipid deposition and ER stress were nullified in cultured hepatocytes by suppressing AMPK through small interfering (si) RNA or 3‐methyladenine (3MA). In animal studies, IL‐38 administration mitigated hepatic steatosis by suppressing the expression of lipogenic proteins and ER stress markers while reversing AMPK phosphorylation and autophagy markers in the livers of HFD‐fed mice. Additionally, AMPK siRNA, but not 3MA, mitigated IL‐38‐enhanced fatty acid oxidation in hepatocytes. In summary, IL‐38 alleviates hepatic steatosis through AMPK/autophagy signaling‐dependent attenuation of ER stress and enhancement of fatty acid oxidation via the AMPK pathway, suggesting a therapeutic strategy for treating NAFLD. [ABSTRACT FROM AUTHOR]

The micronutrient trivalent chromium, 3 + (Cr(III)), is postulated to play a role in carbohydrate, lipid, and protein metabolism. Although the mechanisms by which chromium mediates its actions are largely unknown, previous studies have suggested that pharmacological doses of chromium improve cardiometabolic symptoms by augmenting carbohydrate and lipid metabolism. Activation of AMP-activated protein kinase (AMPK) was among the many mechanisms proposed to explain the salutary actions of chromium on carbohydrate metabolism. However, the molecular pathways leading to the activation of AMPK by chromium remained elusive. In an elegant series of studies, Sun and coworkers recently demonstrated that chromium augments AMPK activation by binding to the beta-subunit of ATP synthase and inhibiting its enzymatic activity. This mini-review attempts to trace the evolving understanding of the molecular mechanisms of chromium leading to the hitherto novel pathway unraveled by Sun and coworkers and its potential implication to our understanding of the biological actions of chromium. [ABSTRACT FROM AUTHOR]

Tipepidine (3-[di-2-thienylmethylene]-1-methylpiperidine) (TP) is a non-narcotic antitussive used in Japan. Recently, the potential application of TP in the treatment of neuropsychiatric disorders, such as depression and attention deficit hyperactivity disorder, has been suggested; however, its functions in energy metabolism are unknown. Here, we demonstrate that TP exhibits a metabolism-improving action. The administration of TP reduced high-fat diet-induced body weight gain in mice and lipid accumulation in the liver and increased the weight of epididymal white adipose tissue (eWAT) in diet-induced obese (DIO) mice. Furthermore, TP inhibited obesity-induced fibrosis in the eWAT. We also found that TP induced AMP-activated protein kinase (AMPK) activation in the eWAT of DIO mice and 3T3-L1 cells. TP-induced AMPK activation was abrogated by the transfection of liver kinase B1 siRNA in 3T3-L1 cells. The metabolic effects of TP were almost equivalent to those of metformin, an AMPK activator that is used as a first-line antidiabetic drug. In summary, TP is a potent AMPK activator, suggesting its novel role as an antidiabetic drug owing to its antifibrotic effect on adipose tissues. [ABSTRACT FROM AUTHOR]

Background: Energy metabolism disorders and neurogenic inflammation play important roles in the central sensitization to chronic migraine (CM). AMP-activated protein kinase (AMPK) is an intracellular energy sensor, and its activation regulates inflammation and reduces neuropathic pain. However, studies on the involvement of AMPK in the regulation of CM are currently lacking. Therefore, this study aimed to explore the mechanism underlying the involvement of AMPK in the central sensitization to CM. Methods: Mice with recurrent nitroglycerin (NTG)-induced CM were used to detect the expression of AMPK protein in the trigeminal nucleus caudalis (TNC). Following intraperitoneal injection of the AMPK activator 5-aminoimidazole-4-carboxyamide ribonucleoside (AICAR) and inhibitor compound C, the mechanical pain threshold, activity level, and pain-like behaviors in the mice were measured. The expression of calcitonin gene-related peptide (CGRP) and cytokines, M1/M2 microglia, and NF-κB pathway activation were detected after the intervention. Results: Repeated NTG injections resulted in a gradual decrease in AMPK protein expression, and the negative regulation of AMPK by increased ubiquitin-like plant homeodomain and RING finger domain 1 (UHRF1) expression may counteract AMPK activation by increasing ADP/ATP. AICAR can reduce the hyperalgesia and pain-like behaviors of CM mice, improve the activity of mice, reduce the expression of CGRP, IL-1β, IL-6, and TNF-α in the TNC region, and increase the expression of IL-4 and IL-10. Moreover, AMPK in TNC was mainly located in microglia. AICAR could reduce the expression of inducible NO synthase (iNOS) in M1 microglia and increase the expression of Arginase 1 (Arg1) in M2 microglia by inhibiting the activation of NF-κB pathway. Conclusions: AMPK was involved in the central sensitization of CM, and the activation of AMPK reduced neuroinflammation in NTG-induced CM mice. AMPK may provide new insights into interventions for energy metabolism disorders and neurogenic inflammation in migraine. [ABSTRACT FROM AUTHOR]

Experimental and clinical studies have revealed the influence of AMP-activated protein kinase (AMPK) signaling on the development of non-alcoholic liver fibrosis. Currently, the results of experimental studies demonstrate that inhibition of AMPK promotes fibrogenesis, while its activation prevents the development of liver fibrosis. The purpose of this work is to establish the effect of activation of AMP-activated protein kinase by the administration of phenformin on the content of glycosaminoglycans, oxyproline and sialic acids in the liver of rats under the conditions of long-term administration of ethanol. The study was conducted on 24 male Wistar rats. The animals were randomly divided into 4 groups of 6 animals each, on which we modeled ethanol-induced liver damage and administered phenformin hydrochloride at a dose of 10 mg/kg. The experiment lasted 63 days. In the liver of rats, the content of total glycosaminoglycans, the concentration of heparin-heparan, keratan-dermatan and chondroitin fractions of glycosaminoglycans, the content of free oxyproline and sialic acids were studied. Long-term alcoholization leads to a violation of the extracellular matrix of the liver of rats, which is evidenced by a decrease in the concentration of proteoglycans and a redistribution of their fractions in the direction of a decrease in anti-inflammatory and regenerative fractions. Chronic intake of alcohol increases the processes of desialylation of glycoconjugates and the intensity of collagenolysis. Activation of AMP-activated protein kinase by administration of phenformin under the conditions of simulating ethanol-induced liver damage leads to an increase in the concentration of glycosaminoglycans due to the growth of heparin-heparan and chondroitin fractions and reduces the intensity of desialylation of glycoconjugates and collagenolysis in the liver of rats. [ABSTRACT FROM AUTHOR]

Acute kidney injury (AKI) disrupts energy metabolism. Targeting metabolism through AMP-activated protein kinase (AMPK) may alleviate AKI. ATX-304, a pan-AMPK activator, was evaluated in C57Bl/6 mice and tubular epithelial cell (TEC) cultures. Mice received ATX-304 (1 mg/g) or control chow for 7 days before cisplatin-induced AKI (CI-AKI). Primary cultures of tubular epithelial cells (TECs) were pre-treated with ATX-304 (20 µM, 4 h) prior to exposure to cisplatin (20 µM, 23 h). ATX-304 increased acetyl-CoA carboxylase phosphorylation, indicating AMPK activation. It protected against CI-AKI measured by serum creatinine (control 0.05 + 0.03 mM vs ATX-304 0.02 + 0.01 mM, P = 0.03), western blot for neutrophil gelatinase-associated lipocalin (NGAL) (control 3.3 + 1.8-fold vs ATX-304 1.2 + 0.55-fold, P = 0.002), and histological injury (control 3.5 + 0.59 vs ATX-304 2.7 + 0.74, P = 0.03). In TECs, pre-treatment with ATX-304 protected against cisplatin-mediated injury, as measured by lactate dehydrogenase release, MTS cell viability, and cleaved caspase 3 expression. ATX-304 protection against cisplatin was lost in AMPK-null murine embryonic fibroblasts. Metabolomic analysis in TECs revealed that ATX-304 (20 µM, 4 h) altered 66/126 metabolites, including fatty acids, tricarboxylic acid cycle metabolites, and amino acids. Metabolic studies of live cells using the XFe96 Seahorse analyzer revealed that ATX-304 increased the basal TEC oxygen consumption rate by 38%, whereas maximal respiration was unchanged. Thus, ATX-304 protects against cisplatin-mediated kidney injury via AMPK-dependent metabolic reprogramming, revealing a promising therapeutic strategy for AKI.

Metformin, known in the medical community as the drug of first choice for type 2 diabetes mellitus, belongs to the group of biguanides and has proven to be an effective treatment in clinical practice. Our knowledge of the pharmacodynamic properties of metformin has long been limited to the following well-known mechanisms: a decrease in hyperglycemia due to an increase in peripheral insulin sensitivity, glucose utilization by cells, inhibition of hepatic gluconeogenesis, an increase in the capacity of all types of membrane glucose transporters, activation of fibrinolysis, and a decrease in the levels of atherogenic lipoproteins. Recent studies show that the range of positive pleiotropic effects of metformin is not limited to the above, and that the molecular mechanisms of its action are more complex than previously thought. This article presents a less known, but equally important action of metformin, in particular, its anti-oncogenic, antiviral, and anti-aging effects. In our study, we highlight that the activation of 5’-adenosine monophosphate-activated protein kinase (AMPK) should be considered as the primary mechanism of action through which almost all beneficial effects are achieved. In the light of recent scientific advances in metformin pharmacology, together with the pathogenetic uncertainty of the term «biguanide», it seems fair and reasonable to apply a more relevant definition to the drugn, namely «AMPK activator».

8-Prenylgenistein (8PG), a genistein derivative, is present in fermented soybeans (Glycine max), including cheonggukjang (CGJ), and exhibits osteoprotective, osteogenic, and antiadipogenic properties. However, the hepatoprotective effects of 8PG and its underlying molecular mechanisms remain largely unexplored. Here, we identified the high binding affinity of 8PG with AMP-activated protein kinase (AMPK) and sirtuin 1 (SIRT1), which acts as a potent AMPK activator that counteracts hepatic steatosis. Notably, 8PG exhibited better pharmacokinetics with greater absorption and higher plasma binding than the positive controls for the target proteins. Moreover, 8PG exerted non-carcinogenic activity in rats and significantly increased AMPK phosphorylation. Compound C, an AMPK inhibitor, did not antagonize 8PG-activated AMPK in HepG2 cells. 8PG significantly attenuated palmitate-induced lipid accumulation and enhanced phosphorylated AMPK and its downstream target, acetyl-CoA carboxylase. Further, 8PG activated nuclear SIRT1 at the protein level, which promoted fatty acid oxidation in palmitate-treated HepG2 cells. Overall, 8PG acts as a potent AMPK activator, further attenuating hepatic steatosis via the SIRT1-mediated pathway and providing new avenues for dietary interventions to treat metabolic dysfunction-associated steatotic liver disease (MASLD).

Sestrins are stress-responsive proteins with antioxidant properties. They participate in cellular redox balance and protect against oxidative damage. This study investigated the effects of Sestrin2 (Sesn2) on osteoclast differentiation and function. Overexpressing Sesn2 in osteoclast precursor cells significantly inhibited receptor activator of nuclear factor κB ligand (RANKL)-induced osteoclastogenesis. This was assessed as reduced expression of various osteoclast markers, including c-Fos, nuclear factor of activated T cells 1 (NFATc1), osteoclast-associated receptor, tartrate-resistant acid phosphatase, and cathepsin K. Conversely, downregulation of Sesn2 produced the opposite effect. Mechanistically, Sesn2 overexpression enhanced AMPK activation and the nuclear translocation of nuclear factor erythroid-derived factor 2-related factor 2 (Nrf2), promoting antioxidant enzymes. Moreover, azithromycin (Azm) induced Sesn2 expression, which suppressed RANKL-induced osteoclast differentiation. Specifically, Azm treatment reduced RANKL-induced production of reactive oxygen species in osteoclasts. Furthermore, intraperitoneal administration of Azm ameliorated RANKL-induced bone loss by reducing osteoclast activity in mice. Taken together, our results suggested that Azm-induced Sesn2 act as a negative regulator of RANKL-induced osteoclast differentiation through the AMPK/NFATc1 signaling pathway. Concisely, targeting Sesn2 can be a potential pharmacological intervention in osteoporosis. [Display omitted] • Sestrin2 inhibits RANKL – induced osteoclast differentiation. • Sestrin2 promotes AMPK activation and Nrf2 nuclear accumulation. • Sestrin2 inhibits RANKL-induced ROS production. • Azithromycin induces expression of sestrin2 on osteoclastogenesis. • Azithromycin blocks RANKL-induced bone loss in vivo. [ABSTRACT FROM AUTHOR]

Saturated free fatty acids are thought to play a critical role in metabolic disorders associated with obesity, insulin resistance, type 2 diabetes (T2D), and their vascular complications via effects on the vascular endothelium. The most abundant saturated free fatty acid, palmitate, exerts lipotoxic effects on the vascular endothelium, eventually leading to cell death. Shear stress activates the endothelial AMP-activated protein kinase (AMPK), a cellular energy sensor, and protects endothelial cells from lipotoxicity, however their relationship is uncertain. Here, we used isoform-specific shRNA-mediated silencing of AMPK to explore its involvement in the long-term protection of macrovascular human umbilical vein endothelial cells (HUVECs) against palmitate lipotoxicity and to relate it to the effects of shear stress. We demonstrated that it is the α1 catalytic subunit of AMPK that is critical for HUVEC protection under static conditions, whereas AMPK-α2 autocompensated a substantial loss of AMPK-α1, but failed to protect the cells from palmitate. Shear stress equally protected the wild type HUVECs and those lacking either α1, or α2, or both AMPK-α isoforms; however, the protective effect of AMPK reappeared after returning to static conditions. Moreover, in human adipose microvascular endothelial cells isolated from obese diabetic individuals, shear stress was a strong protector from palmitate lipotoxicity, thus highlighting the importance of circulation that is often obstructed in obesity/T2D. Altogether, these results indicate that AMPK is important for vascular endothelial cell protection against lipotoxicity in the static environment, however it may be dispensable for persistent and more effective protection exerted by shear stress. [ABSTRACT FROM AUTHOR]

Purpose: The acquisition of osseointegration during implant therapy is slower and poorer in patients with diabetes compared with healthy persons. The serum concentration of adiponectin in patients with type II diabetes is lower than that of healthy persons via the suppression of AMP-activated protein kinase (AMPK). Therefore, we hypothesized that the AMPK activation enhances bone formation around implants, resulting in the improved acquisition of osseointegration. The purpose of this study was to evaluate the impact of AMPK activation on osteoblast differentiation and its mechanism of downstream signaling on titanium disc (Ti). Methods: Confluent mouse pre-osteoblasts (MC3T3-E1) cells (1 × 105 cells/well) were cultured with BMP-2 for osteoblast differentiation, in the presence or absence AICAR, an AMPK activator. We examined the effects of AMPK activation on osteoblast differentiation and the underlying mechanism on a Ti using a CCK8 assay, a luciferase assay, quantitative RT-PCR, and western blotting. Results: Although the proliferation rate of osteoblasts was not different between a Ti and a tissue culture polystyrene dish, the addition of AICAR, AMPK activator slightly enhanced osteoblast proliferation on the Ti. AICAR enhanced the BMP-2-dependent transcriptional activity on the Ti, leading to upregulation in the expression of osteogenesis-associated molecules. AICAR simultaneously upregulated the expression of autophagy-associated molecules on the Ti, especially LC3-II. AdipoRon, an adiponectin receptor type1/type2 activator activated AMPK, and upregulated osteogenesis-associated molecules on Ti. Conclusions: AMPK activation enhances osteoblast differentiation on a Ti via autophagy, suggesting that it promotes the acquisition of osseointegration during implant therapy. [ABSTRACT FROM AUTHOR]

Objective To explore the mechanism of Lkb1 regulated epithelial regeneration in asthma by airway organoid culture. Methods Lkb1f/f (the control group, n=10) and Scgb1a1CreER; Lkb1f/f mice (the Lkb1 knockout group, n=9) were taken to establish allergic asthma models by aerosol inhalation of ovalbumin (OVA). Bronchial lavage fluid (BALF) and lung tissue were collected. The number of inflammatory cells in BALF were counted. The amount of CLCA3 positive cells was compared by immunofluorescence staining of lung tissue sections. Club cells were selected by flow cytometry for organoid culture. The average diameter of organoids and organoid formation rate were calculated. Expression levels of goblet cell marker CLCA3, cilia cell markers FOXJ1 and AMPK in Club cells were detected by RT-PCR. Results There were no significant differences in the number of macrophages, eosinophils, neutrophils and lymphocytes in BALF between the control group and the Lkb1 knockout group. The number of CLCA3 positive cells were decreased after Lkb1 knockout. Results of organoid culture showed that the average diameter of organoids derived from Club cells and organoid formation rate were decreased after the absence of Lkb1. The expression of FOXJ1 was reduced. After Lkb1 deletion, the expression of AMPKα in Club cells were decreased and the proliferation of Club cells was inhibited. Activation of AMPK, the downstream signaling pathway of Lkb1, could attenuate the effect of Lkb1 deficiency on the regeneration of Club cells. Conclusion Lkb1 promotes the proliferation of airway progenitor cells by AMPK pathway. [ABSTRACT FROM AUTHOR]

AMP-activated protein kinase (AMPK) is the central component of a signalling pathway that senses energy stress and triggers a metabolic switch away from anabolic processes and towards catabolic processes. There has been a prolonged focus in the pharmaceutical industry on the development of AMPK-activating drugs for the treatment of metabolic disorders such as Type 2 diabetes and non-alcoholic fatty liver disease. However, recent findings suggest that AMPK inhibitors might be efficacious for treating certain cancers, especially lung adenocarcinomas, in which the PRKAA1 gene (encoding the α1 catalytic subunit isoform of AMPK) is often amplified. Here, we study two potent AMPK inhibitors, BAY-3827 and SBI-0206965. Despite not being closely related structurally, the treatment of cells with either drug unexpectedly caused increases in AMPK phosphorylation at the activating site, Thr172, even though the phosphorylation of several downstream targets in different subcellular compartments was completely inhibited. Surprisingly, the two inhibitors appear to promote Thr172 phosphorylation by different mechanisms: BAY-3827 primarily protects against Thr172 dephosphorylation, while SBI-0206965 also promotes phosphorylation by LKB1 at low concentrations, while increasing cellular AMP:ATP ratios at higher concentrations. Due to its greater potency and fewer off-target effects, BAY-3827 is now the inhibitor of choice for cell studies, although its low bioavailability may limit its use in vivo. [ABSTRACT FROM AUTHOR]