bims-amsmem 2022-09-11 papers

bims-amsmem

Biomed News

on AMPK signaling mechanism in energy metabolism

Issue of 2022–09–11
twenty papers selected by
Dipsikha Biswas, Københavns Universitet

The Distinct Roles of LKB1 and AMPK in p53-Dependent Apoptosis Induced by Cisplatin.
Differential Protective Effect of Resveratrol and Its Microbial Metabolites on Intestinal Barrier Dysfunction is Mediated by the AMPK Pathway.
Tangeretin Protects Mice from Alcohol-Induced Fatty Liver by Activating Mitophagy through the AMPK-ULK1 Pathway.
Melatonin prevents diabetes-induced nephropathy by modulating the AMPK/SIRT1 axis: Focus on autophagy and mitochondrial dysfunction.
Oxytocin ameliorates high glucose- and ischemia/reperfusion-induced myocardial injury by suppressing pyroptosis via AMPK signaling pathway.
Metformin alleviates long-term high-fructose diet-induced skeletal muscle insulin resistance in rats by regulating purine nucleotide cycle.
Lycopene ameliorates hyperlipidemia via potentiation of AMP-activated protein kinase and inhibition of ATP-citrate lyase in diabetic hyperlipidemic rat model.
Laurolitsine ameliorates type 2 diabetes by regulating the hepatic LKB1-AMPK pathway and gut microbiota.
Blocking AMPK signalling to acetyl-CoA carboxylase increases cisplatin-induced acute kidney injury and suppresses the benefit of metformin.
Sestrin2 suppresses ferroptosis to alleviate septic intestinal inflammation and barrier dysfunction.
Arctium lappa leaves based on network pharmacology and experimental validation attenuate atherosclerosis by targeting the AMPK-mediated PPARG/LXRα pathway.
In Vitro and In Vivo Sucrosomial® Berberine Activity on Insulin Resistance.
The Degradation of TMEM166 by Autophagy Promotes AMPK Activation to Protect SH-SY5Y Cells Exposed to MPP.
IL10/AMPK pathway was associated with the hippocampal anti-inflammatory response to high-sugar and high-fat diet withdrawal.
Role of liver AMPK and GCN2 kinases in the control of postprandial protein metabolism in response to mid-term high or low protein intake in mice.
Autophagy in Rat Müller Glial Cells Is Modulated by the Sirtuin 4/AMPK/mTOR Pathway and Induces Apoptosis under Oxidative Stress.
Wnt inhibitory factor 1 ameliorated diabetic retinopathy through the AMPK/mTOR pathway-mediated mitochondrial function.
Repurposing nitazoxanide as a novel anti-atherosclerotic drug based on mitochondrial uncoupling mechanisms.
ASC Regulates Subcutaneous Adipose Tissue Lipogenesis and Lipolysis via p53/AMPKα Axis.
Resveratrol reverses TGF-β1-mediated invasion and metastasis of breast cancer cells via the SIRT3/AMPK/autophagy signal axis.

Int J Mol Sci. 2022 Sep 02. pii: 10064. [Epub ahead of print]23(17):

The Distinct Roles of LKB1 and AMPK in p53-Dependent Apoptosis Induced by Cisplatin.

Tatsuya Shimada, Yohsuke Yabuki, Takuya Noguchi, Mei Tsuchida, Ryuto Komatsu, Shuhei Hamano, Mayuka Yamada, Yusuke Ezaki, Yusuke Hirata, Atsushi Matsuzawa.

  Liver kinase B1 (LKB1) is a serine/threonine protein kinase that acts as a key tumor suppressor protein by activating its downstream kinases, such as AMP-activated protein kinase (AMPK). However, the regulatory actions of LKB1 and AMPK on DNA damage response (DDR) remain to be explored. In this study, we investigated the function of LKB1 in DDR induced by cisplatin, a representative DNA-damaging agent, and found that LKB1 stabilizes and activates p53 through the c-Jun N-terminal kinase (JNK) pathway, which promotes cisplatin-induced apoptosis in human fibrosarcoma cell line HT1080. On the other hand, we found that AMPKα1 and α2 double knockout (DKO) cells showed enhanced stabilization of p53 and increased susceptibility to apoptosis induced by cisplatin, suggesting that AMPK negatively regulates cisplatin-induced apoptosis. Moreover, the additional stabilization of p53 and subsequent apoptosis in AMPK DKO cells were clearly canceled by the treatment with the antioxidants, raising the possibility that AMPK suppresses the p53 activation mediated by oxidative stress. Thus, our findings unexpectedly demonstrate the reciprocal regulation of p53 by LKB1 and AMPK in DDR, which provides insights into the molecular mechanisms of DDR.

Keywords:  AMPKα; DNA damage; DNA damage response; LKB1; apoptosis; cisplatin

DOI:  https://doi.org/10.3390/ijms231710064
J Agric Food Chem. 2022 Sep 06.

Differential Protective Effect of Resveratrol and Its Microbial Metabolites on Intestinal Barrier Dysfunction is Mediated by the AMPK Pathway.

Bowei Zhang, Yunhui Zhang, Xiaoxia Liu, Jia Yin, Xiang Li, Xuejiao Zhang, Xiaolong Xing, Jin Wang, Shuo Wang.

  The effectiveness of resveratrol (RES) on intestinal barrier dysfunction and colitis has been extensively studied. However, the specific effects of its microbial metabolites on gut barrier function remain unclear. Hence, we compared the protective effects of RES and its microbial metabolites dihydroresveratrol (DHR) and 3-(4-hydroxyphenyl)-propionic acid (4HPP) against intestinal barrier injury and colitis. Only 4HPP and RES significantly reduced paracellular permeability and the secretion of proinflammatory cytokines in lipopolysaccharides (LPS)-treated intestinal Caco-2 cells, which was consistent with the upregulation in tight junction (TJ) proteins. Furthermore, RES and 4HPP ameliorated intestinal barrier dysfunction and colonic inflammation in colitis mice, while DHR did not. In particular, the expressions of intestinal TJ proteins and Muc2 were restored by RES and 4HPP. The molecular mechanism involved the adenosine monophosphate-activated protein kinase (AMPK)-mediated activation of CDX2 and the regulation of the SIRT1/NF-κB pathway. These findings provide new insights into understanding the protective effects of RES against intestinal barrier damage and colitis.

Keywords:  3-(4-hydroxyphenyl)-propionic acid; AMPK; epithelial barrier; inflammatory bowel disease (IBD); resveratrol

DOI:  https://doi.org/10.1021/acs.jafc.2c04101
J Agric Food Chem. 2022 Sep 05.

Tangeretin Protects Mice from Alcohol-Induced Fatty Liver by Activating Mitophagy through the AMPK-ULK1 Pathway.

Jianjin Guo, Yuan Chen, Fang Yuan, Li Peng, Chen Qiu.

  Alcoholic beverages are widely consumed all over the world, but continuous ethanol exposure leads to hepatic steatosis that, without proper treatment, will later develop into severe liver disorders. In this study, we investigated the potential protective effect of tangeretin, a flavonoid derived from citrus peel, against alcoholic fatty liver. The in vivo effects of tangeretin were analyzed by oral intake in a chronic-binge alcohol feeding C57BL/6j mouse model, while the underlying mechanism was explored by in vitro studies performed on ethanol-treated hepatic AML-12 cells. Ethanol feeding increased the serum alanine aminotransferase and aspartate aminotransferase levels, the liver weight, and the serum and liver triacylglycerol contents, whereas 20 and 40 mg/kg tangeretin treatment promoted a dose-dependent suppression of these effects. Interestingly, tangeretin prevented increases in the liver oxidative stress level and protected the hepatocyte mitochondria from ethanol-induced morphologic abnormalities. A mechanistic study showed that 20 μM tangeretin treatment activated mitophagy through an AMP-activated protein kinase (AMPK)-uncoordinated 51-like kinase 1 (Ulk1) pathway, thereby restoring mitochondria respiratory function and suppressing steatosis. By contrast, blocking the AMPK-Ulk1 pathway with compound C reversed the hepatoprotective effect of tangeretin. Overall, tangeretin activated mitophagy and protected against ethanol-induced hepatic steatosis through an AMPK-Ulk1-dependent mechanism.

Keywords:  AMPK; alcoholic fatty liver; chronic-binge ethanol model; mitophagy; tangeretin

DOI:  https://doi.org/10.1021/acs.jafc.2c02927
Cell Biol Int. 2022 Sep 10.

Melatonin prevents diabetes-induced nephropathy by modulating the AMPK/SIRT1 axis: Focus on autophagy and mitochondrial dysfunction.

Jain Siddhi, Bhoomika Sherkhane, Anil Kumar Kalavala, Vijay Arruri, Ravichandiran Velayutham, Ashutosh Kumar.

  Impaired nutrient sensing mechanisms such as AMPK/silent information regulator type 1 (SIRT1) axis and autophagy in renal cells upon chronic diabetic condition accelerate renal injury and upregulating these mechanisms has been reported to prevent renal damage. Melatonin, a neuroendocrine agent, also possess antioxidant and AMPK modulatory effect. In the current study, the protective effect of melatonin against diabetic renal injury was assessed in streptozotocin-induced diabetic nephropathy model and in in vitro model of high-glucose-induced tubular injury. Melatonin (3 and 10 mg/kg) was administered for 28 days after 4 weeks of diabetes induction in Sprague-Dawley rats. For in vitro model, the NRK-52E cells were co-incubated with high glucose and melatonin (25 and 50 μM). Melatonin supplementation abrogated the diabetes-induced renal injury and improved renal function in diabetic rats. Immunoblot analysis of renal tissue lysates revealed improved expression of AMPK, as well as upregulated the expression of nuclear factor erythroid 2-related factor 2, SIRT1, PGC-1α, TFAM and enhanced autophagy upon melatonin treatment in diabetic rats. Likewise, melatonin treatment in high glucose exposed NRK-52E cells improved expression of AMPK, enhanced mitochondrial biogenesis and positively modulated autophagy. However, these effects were repressed upon inhibition of AMPK activity in NRK-52E cells by treatment of Compound-C, suggesting that the protective effects of melatonin were mainly mediated through activation of AMPK. These results suggest that melatonin might mediate the renoprotective effect by upregulating the AMPK/SIRT1 axis, enhancing the autophagy and mitochondrial health in DIabetic Nephropathy.

Keywords:  AMPK; autophagy; diabetic nephropathy; kidney; melatonin; oxidative stress

DOI:  https://doi.org/10.1002/cbin.11899
Biomed Pharmacother. 2022 Sep;pii: S0753-3322(22)00887-3. [Epub ahead of print]153 113498

Oxytocin ameliorates high glucose- and ischemia/reperfusion-induced myocardial injury by suppressing pyroptosis via AMPK signaling pathway.

Mengran Yao, Zhuoran Wang, Leyu Jiang, Lingyan Wang, Yuqiao Yang, Quan Wang, Xi Qian, Weijun Zeng, Wei Yang, Rongbi Liang, Jinqiao Qian.

  The present study aimed to explore the role of oxytocin (OT) in myocardial injury induced by ischemia/reperfusion (I/R) and hyperglycemia and its underlying mechanisms. In this study, the isolated rat hearts underwent I/R in Langendorff perfusion model and H9c2 cells were subjected to hypoxia/reoxygenation (H/R) to establish an in vitro model. I/R injury was induced by exposing the rat hearts to 40 min of global ischemia followed by 60 min of reperfusion. H9c2 cells were cultured under the normoglycemic or hyperglycemic condition with or without pretreatment of OT, and then exposed to 4 h of hypoxia and 2 h of reoxygenation. Measurement indicators included myocardial infarct size assessed by triphenyltetrazolium chloride (TTC) staining and hemodynamic parameters in the ex vivo model as well as cell viability detected by cell counting kit 8 (CCK-8), apoptotic rate evaluated by flow cytometry, and the protein expressions by Western blot. The findings demonstrated that OT attenuated myocardial I/R injury. First, OT preconditioning significantly reduced hemodynamic disorders and myocardial infarct sizes. In addition, OT increased cell viability, decreased cell apoptosis and the expressions of IL-18, IL-1β, cleaved-caspase-1, NLRP3, and GSDMD following H/R. NLRP3 activator nigericin eliminated the beneficial effects of OT in H9c2 cells. Furthermore, OT also activated AMPK and decreased the expressions of pyroptosis-related proteins. Administration of AMPK inhibitor compound C blunted OT-induced AMPK phosphorylation and elevated the expressions of pyroptosis-related proteins in H9c2 cells subjected to H/R with hyperglycemia. OT alleviates myocardial I/R injury with hyperglycemia by inhibiting pyroptosis via AMPK/NLRP3 signaling pathway.

Keywords:  AMPK; Hyperglycemia; Myocardial ischemia/reperfusion injury; NLRP3; Oxytocin; Pyroptosis

DOI:  https://doi.org/10.1016/j.biopha.2022.113498
Eur J Pharmacol. 2022 Sep 01. pii: S0014-2999(22)00495-2. [Epub ahead of print] 175234

Metformin alleviates long-term high-fructose diet-induced skeletal muscle insulin resistance in rats by regulating purine nucleotide cycle.

Juanjuan Cheng, Lieqiang Xu, Qiuxia Yu, Guoshu Lin, Xingdong Ma, Mengyao Li, Fengkun Guan, Yuhong Liu, Xiaoqi Huang, Jianhui Xie, Jiannan Chen, Ziren Su, Yucui Li.

  Nutrient excess caused by excessive fructose intake can lead to insulin resistance and dyslipidemia, which further causes the development of metabolic syndrome. Metformin is a well-known AMPK activator widely used for the treatment of metabolic syndrome, while the mechanism of AMPK activation remains unclear. The present study aimed to investigate the pharmacological effects of metformin on fructose-induced insulin resistance rat, and the potential mechanism underlying AMPK activation in skeletal muscle tissue. Results indicated that metformin significantly ameliorated features of insulin resistance, including body weight, Lee's index, hyperinsulinemia, dyslipidemia, insulin intolerance and pancreatic damage. Moreover, treatment with metformin attenuated the inflammatory response in serum and enhanced the antioxidant capacity in skeletal muscle tissue. The therapeutic effects of metformin on fructose-induced insulin resistance may be related to the activation of AMPK to regulate Nrf2 pathway and mitochondrial abnormality. Additionally, metformin suppressed the expression of adenosine monophosphate deaminase 1 (AMPD1) and up-regulated the expression of adenylosuccinate synthetase (ADSS) in the purine nucleotide cycle (PNC), which facilitated the increase of AMP level and the ratio of AMP/ATP. Therefore, we proposed a novel mechanism that metformin activated AMPK via increasing AMP by regulating the expression of AMPD1 and ADSS in PNC pathway.

Keywords:  Fructose; Insulin resistance; Metformin; Mitochondrial; Nrf2 signal pathway; Purine nucleotide cycle

DOI:  https://doi.org/10.1016/j.ejphar.2022.175234
Life Sci. 2022 Sep 05. pii: S0024-3205(22)00634-8. [Epub ahead of print] 120934

Lycopene ameliorates hyperlipidemia via potentiation of AMP-activated protein kinase and inhibition of ATP-citrate lyase in diabetic hyperlipidemic rat model.

Mohamed M Elseweidy, Alaa S Elawady, Mohammed S Sobh, Gehad M Elnagar.

   AIM: The present study aimed mainly to demonstrate the metabolic effects of lycopene (LYC) or atorvastatin (ATOR) in diabetic hyperlipidemic rat model.
MAIN METHODS: Rats were randomly classified into four groups; the first was fed normal chow diet (NC) while the other three groups received streptozotocin (STZ) along with CCT-diet. The second group received no treatment (diabetic hyperlipidemic control, DHC), the third one received ATOR (50 mg/kg/day) while the fourth one received LYC (20 mg/kg/day). Serum and tissue samples were collected for biochemical and histological evaluations.
KEY FINDINGS: DHC rats demonstrated significant hyperglycemia, dyslipidemia, increased hepatic fatty acids synthetase (FAS), malondialdehyde (MDA), tumor necrosis factor- alpha (TNF-α), 3-hydroxy 3-methylglutaryl coenzyme A (HMG-CoA) reductase and ATP Citrate lyase (ACLY). However, hepatic reduced glutathione (GSH) and phosphorylated form of AMP-activated protein kinase (AMPK-P) activities showed significant decrease. ATOR or LYC administration induced hypoglycemic and hypolipidemic effects; decreased hepatic levels of MDA, TNF-α, HMG-CoA reductase, ACLY and FAS along with GSH and AMPK-P increases. Histopathological findings showed clear correlation with the biomarkers results.
SIGNIFICANCE: LYC demonstrated favorable significant effects regarding the biomarkers studied as compared to ATOR and may be expressed as a potent therapeutic agent of natural origin for hyperlipidemia complications either alone or in combination with other hypolipidemic drugs.

Keywords:  AMPK-P; ATP citrate lyase; Atorvastatin; Hyperlipidemia; Lycopene

DOI:  https://doi.org/10.1016/j.lfs.2022.120934
Phytomedicine. 2022 Aug 31. pii: S0944-7113(22)00512-8. [Epub ahead of print]106 154423

Laurolitsine ameliorates type 2 diabetes by regulating the hepatic LKB1-AMPK pathway and gut microbiota.

Zhang Yong, Wang Ruiqi, Yang Yanan, Ma Ning, Zhou Zhi, Tan Yinfeng, Dong Lin, Li Yiying, Lu Weiying, Wu Chongming, Zhang Xiaopo.

   BACKGROUND: Type 2 diabetes mellitus (DM) is a highly prevalent chronic metabolic disease. Effective antidiabetic drugs are needed to improve and expand the available treatments. Using the ob/ob diabetic mouse model, we previously demonstrated that the alkaloid-rich extract from Litsea glutinosa bark (CG) has potent antidiabetic effects and that laurolitsine (LL) is the richest alkaloid in CG.
PURPOSE: We conducted a systematic investigation of the antidiabetic effects and potential mechanisms of LL in vitro and in vivo.
METHODS: The antidiabetic effects of LL and its mechanisms of action were explored in HL-7702 hepatocytes in vitro and in db/db mice in vivo by a series of experiments, including cellular toxicity analysis, glucose consumption analysis, serum/liver biochemical analysis, pathological examinations, Western blots, RNA-seq analysis, and gut microbiota analysis.
RESULTS: LL stimulated glucose consumption and activated AMP-activated protein kinase (AMPK) without inducing lactic acid production or cytotoxicity in vitro. LL had potent antidiabetic effects with hypoglycemic activity in vivo. It improved insulin resistance, glucose tolerance and lipid metabolism; protected liver, renal and pancreatic functions; and promoted weight loss in db/db mice. Transcriptomic analysis suggested that the antidiabetic effects of LL involved the regulation of mitochondrial oxidative phosphorylation. We further demonstrated that LL effectively activated the hepatic liver kinase B1 (LKB1)/AMPK pathway by regulating the ADP/ATP ratio. Simultaneously, LL significantly modulated the gut microbial community, specifically decreasing the abundances of Mucispirillum schaedleri and Anaerotruncus_sp_G3_2012, which might also contribute to its antidiabetic effects.
CONCLUSION: These results suggest that LL is a promising antidiabetic drug candidate that may improve glucolipid metabolism via modulation of the hepatic LKB1/AMPK pathway and the gut microbiota.

Keywords:  Diabetes; Gut microbiota; LKB1/AMPK pathway; Laurolitsine

DOI:  https://doi.org/10.1016/j.phymed.2022.154423
Biomed Pharmacother. 2022 Sep;pii: S0753-3322(22)00766-1. [Epub ahead of print]153 113377

Blocking AMPK signalling to acetyl-CoA carboxylase increases cisplatin-induced acute kidney injury and suppresses the benefit of metformin.

Geoff Harley, Marina Katerelos, Kurt Gleich, David P de Souza, Vinod K Narayana, Bruce E Kemp, David A Power, Peter F Mount.

   BACKGROUND: Acute kidney injury (AKI) is accompanied by dysregulation of cellular energy metabolism and accumulation of intracellular lipid. Phosphorylation of acetyl-CoA carboxylase (ACC) by AMP-activated protein kinase (AMPK) inhibits fatty acid synthesis and promotes fatty acid oxidation (FAO), vital for kidney tubular epithelial cells (TECs). The diabetes drug metformin is protective in models of AKI; however, it is not known whether ACC phosphorylation plays a role.
METHODS: Cisplatin-induced AKI (CI-AKI) was established in ACC1/2 double knock-in (ACC1/2DKI) mice, harbouring mutations that disrupt fatty acid metabolism, and the role of metformin was studied in this model. Outcomes measured included serum biochemistry, expression of kidney injury markers such as neutrophil gelatinase-associated lipocalin (NGAL), and metabolomic analysis.
FINDINGS: ACC1/2DKI mice demonstrated more severe CI-AKI than wild type (WT), as assessed by serum urea and creatinine, histological injury, and expression of NGAL and interleukin-6. Metformin protected against AKI in WT mice, shown by reduced NGAL, but this effect was absent in ACC1/2DKI mice. In cultured TECs exposed to cisplatin, metformin reduced expression of cleaved caspase-3, however, this effect was diminished in ACC1/2DKI TECs. Analysis of kidney polar metabolites found numerous differences between metformin-treated CI-AKI in ACC1/2DKI and WT mice, involving multiple pathways of amino acid, nucleoside, and energy metabolism.
INTERPRETATION: Severity of CI-AKI is exacerbated by the inability to regulate metabolism via phosphorylation of ACC. ACC phosphorylation contributes to the protective effect of metformin against AKI, influencing multiple mechanisms involved in the pathogenesis of kidney injury.

Keywords:  AMP-activated protein kinase; Acetyl-CoA carboxylase; Cisplatin-induced acute kidney injury; Fatty acid oxidation; Metabolomics; Metformin; Phosphorylation

DOI:  https://doi.org/10.1016/j.biopha.2022.113377
Immunopharmacol Immunotoxicol. 2022 Sep 06. 1-22

Sestrin2 suppresses ferroptosis to alleviate septic intestinal inflammation and barrier dysfunction.

Wei Liu, Chanchan Xu, Zhiqiang Zou, Qinyong Weng, Ying Xiao.

   OBJECTIVE: Alterations in intestinal function play a crucial role in the pathogenesis of sepsis, and the repair of the intestinal barrier is a potential strategy for the treatment of sepsis. Sestrin2 (SESN2), a highly conserved stress-responsive protein, can be induced in response to stress.
AIM: This paper aimed to explore the role and mechanism of SESN2 in septic intestinal dysfunction. Methods: Blood samples were collected from patients with septic intestinal dysfunction, and Caco-2 cells were subjected to lipopolysaccharide (LPS) to construct in vitro models. The expression level of SESN2 was determined in the blood samples and cells. The impacts of SESN2 overexpression on cell inflammation, oxidative stress, barrier integrity, and MAPK/Nrf2 signaling were evaluated. To determine the mediated role of MAPK signaling and ferroptosis, AMPK inhibitor (Compound C) and ferroptosis inducer (erastin) were separately used to treat cells, and the influences on the above aspects in cells were assessed.
RESULTS: The expression level of SESN2 was down-regulated in patients with septic intestinal dysfunction and LPS-induced cells. SESN2 overexpression was found to suppress cell inflammation and oxidative stress, maintain barrier integrity and activate AMPK/Nrf2 signaling. Following the AMPK signaling was inhibited or the ferroptosis was triggered, the effects of SESN2 overexpression on the cells were both reversed.
CONCLUSION: Reduced SESN2 contributed to inflammatory response and barrier dysfunction in septic intestinal dysfunction by promoting ferroptosis via activating the AMPK/Nrf2 signaling pathway.

Keywords:  AMPK; Sestrin2; ferroptosis; intestinal barrier; septic intestinal dysfunction

DOI:  https://doi.org/10.1080/08923973.2022.2121927
Biomed Pharmacother. 2022 Sep;pii: S0753-3322(22)00892-7. [Epub ahead of print]153 113503

Arctium lappa leaves based on network pharmacology and experimental validation attenuate atherosclerosis by targeting the AMPK-mediated PPARG/LXRα pathway.

Mengmeng Wang, Bingdi Cui, Man Gong, Qiuyan Liu, Xingxu Zhuo, Jiangnan Lv, Lianhe Yang, Xiaoqian Liu, Zhimin Wang, Liping Dai.

  Arctium lappa (A. lappa) leaves are widely used in various traditional Chinese herbal formulae to ameliorate atherosclerosis (AS) and its complications such as stroke; however, there is no literature reporting the anti-atherosclerotic effect and mechanism of A. lappa leaves thus far. In the present study, we used network pharmacology and molecular docking approaches to examine the protective effect and potential mechanism of A. lappa leaves against AS in vivo and in vitro. From the network pharmacology, PPARG, HMGCR and SREBF2 were identified as the core targets of A. lappa leaves against AS. Further enrichment analyses of GO and KEGG pathways suggested that A. lappa leaves might play an anti-AS role by regulating metabolic processes and PPAR signalling pathways. The results of molecular docking experiment revealed that the major components of A. lappa leaves interacted with cholesterol efflux-regulating core proteins (PPARG, LXRα, ABCA1, and ABCG1), AMPK and SIRT1. Both in vivo and in vitro experimental results demonstrated that treatment with A. lappa leaves significantly lowered TC and LDL-C, increased HDL-C, and reduced cholesterol accumulation in the liver and aorta of the AS rat model and the foam cell model. Importantly, both in vivo and in vitro experimental results demonstrated that A. lappa leaves regulate the activity of the PPARG/LXRα signalling and AMPK/SIRT1 signalling pathways. Moreover, after treatment with the AMPK inhibitor Compound C in vitro, the improvement induced by A. lappa leaves was significantly reversed. In conclusion, A. lappa leaves attenuated AS-induced cholesterol accumulation by targeting the AMPK-mediated PPARG/LXRα pathway and promoting cholesterol efflux.

Keywords:  AMPK; Arctium lappa leaves; Atherosclerosis; Cardiovascular disease; Cholesterol efflux; PPARG/LXRα

DOI:  https://doi.org/10.1016/j.biopha.2022.113503
Nutrients. 2022 Aug 31. pii: 3595. [Epub ahead of print]14(17):

In Vitro and In Vivo Sucrosomial® Berberine Activity on Insulin Resistance.

Maria Giovanna Lupo, Elisa Brilli, Virginia De Vito, Germano Tarantino, Stefania Sut, Irene Ferrarese, Giovanni Panighel, Daniela Gabbia, Sara De Martin, Stefano Dall'Acqua, Nicola Ferri.

  Background: Berberine is a natural alkaloid with hypoglycemic properties. However, its therapeutic use is limited by a very low oral bioavailability. Here we developed a new oral formulation of berberine based on Sucrosomial® technology and tested its effect on insulin resistance. Methods: Sucrosomial® berberine was first tested in vitro in the hepatoma cell line Huh7 to assess its effect on proteins involved in glucose homeostasis and insulin resistance. The pharmacokinetics and efficacy on insulin resistance were then studied in C57BL/6 mice fed with standard (SD) and high-fat diet (HFD) for 16 weeks and treated daily during the last 8 weeks with oral gavage of Sucrosomial® berberine or berberine. Results: Sucrosomial® berberine did not affect Huh7 cell viability at concentrations up to 40 µM. Incubation of Huh7 with 20 µM of Sucrosomial® and control berberine induced glucokinase (GK) and the phosphorylation of 5'-adenosine monophosphate (AMP)-activated protein kinase (AMPK), both known targets for the control of insulin resistance. In vivo, we observed an 8-fold higher plasma concentration after 3 weeks of oral administration of 50 mg/kg/day of Sucrosomial® formulation compared to berberine. HFD, compared to SD, induced insulin resistance in mice as determined by oral glucose tolerance test (OGTT). The treatment with a 6.25 mg/kg/daily dose of Sucrosomial® berberine significantly reduced the area under the curve (AUC) of OGTT (73,103 ± 8645 vs. 58,830 ± 5597 mg/dL × min), while control berberine produced the same effects at 50 mg/Kg/day (51518 ± 1984 mg/dL × min). Under these conditions, the two formulations resulted in similar berberine plasma concentration in mice. Nevertheless, a different tissue distribution of metabolites was observed with a significant accumulation of reduced, demethylated and glucuronide berberine in the brain after the oral administration of the Sucrosomial® form. Glucuronide berberine plasma concentration was higher with Sucrosomial® berberine compared to normal berberine. Finally, we observed similar increases of AMPK phosphorylation in the liver in response to the treatment with Sucrosomial® berberine and berberine. Conclusions: The Sucrosomial® formulation is an innovative and effective technology to improve berberine gastrointestinal (GI) absorption with proven in vitro and in vivo activity on insulin resistance.

Keywords:  AMPK; OGTT; Sucrosomial®; berberine; gastrointestinal absorption; insulin

DOI:  https://doi.org/10.3390/nu14173595
Cells. 2022 Aug 30. pii: 2706. [Epub ahead of print]11(17):

The Degradation of TMEM166 by Autophagy Promotes AMPK Activation to Protect SH-SY5Y Cells Exposed to MPP.

Zhaozhong Liao, Zunshuang Gong, Zhe Wang, Weiyan Yang, Wenjing Liu, Lin Hou, Xiaokun Liu, Junnan Hua, Bin Wang, Ning Li.

  Neuronal oxidative stress caused by mitochondrial dysfunction plays a crucial role in the development of Parkinson's disease (PD). Growing evidence shows that autophagy confers neuroprotection in oxidative-stress-associated PD. This work aims to investigate the involvement of TMEM166, an endoplasmic-reticulum-localized autophagy-regulating protein, in the process of PD-associated oxidative stress through the classic cellular PD model of neuroblastoma SH-SY5Y cells exposed to 1-methyl-4-phenylpyridinium (MPP+). Reactive oxygen species (ROS) production and mitochondrial membrane potential were checked to assess the oxidative stress induced by MPP+ and the cellular ATP generated was determined to evaluate mitochondrial function. The effect on autophagy induction was evaluated by analyzing p62 and LC3-II/I expression and by observing the LC3 puncta and the colocalization of LC3 with LAMP1/ LAMP2. The colocalization of mitochondria with LC3, the colocalization of Tom20 with LAMP1 and Tom20 expression were analyzed to evaluate mitophagy. We found that TMEM166 is up-regulated in transcript levels, but up-regulated first and then down-regulated by autophagic degradation in protein levels upon MPP+-treatment. Overexpression of TMEM166 induces mitochondria fragmentation and dysfunction and exacerbates MPP+-induced oxidative stress and cell viability reduction. Overexpression of TMEM166 is sufficient to induce autophagy and mitophagy and promotes autophagy and mitophagy under MPP+ treatment, while knockdown of TMEM166 inhibits basal autophagic degradation. In addition, overexpressed TMEM166 suppresses AMPK activation, while TMEM166 knockdown enhances AMPK activation. Pharmacological activation of AMPK alleviates the exacerbation of oxidative stress induced by TMEM166 overexpression and increases cell viability, while pharmacological inhibition mitophagy aggravates the oxidative stress induced by MPP+ treatment combined with TMEM166 overexpression. Finally, we find that overexpressed TMEM166 partially localizes to mitochondria and, simultaneously, the active AMPK in mitochondria is decreased. Collectively, these findings suggest that TMEM166 can translocate from ER to mitochondria and inhibit AMPK activation and, in response to mitochondrial oxidative stress, neuronal cells choose to up-regulate TMEM166 to promote autophagy/mitophagy; then, the enhancing autophagy/mitophagy degrades the TMEM166 to activate AMPK, by the two means to maintain cell survival. The continuous synthesis and degradation of TMEM166 in autophagy/mitochondria flux suggest that TMEM166 may act as an autophagy/mitochondria adaptor.

Keywords:  AMPK; EVA1A; PINK1/Parkin; Parkinson’s disease; SH-SY5Y cells; TMEM166; autophagy; mitochondria; mitophagy; oxidative stress

DOI:  https://doi.org/10.3390/cells11172706
Inflamm Res. 2022 Sep 09.

IL10/AMPK pathway was associated with the hippocampal anti-inflammatory response to high-sugar and high-fat diet withdrawal.

Breno Picin Casagrande, Luciana Pellegrini Pisani, Debora Estadella.

   OBJECTIVE: The present experimental study aimed to evaluate the effect of consuming an obesogenic diet (OD) on serum and hippocampal inflammation and proteins related to energy metabolism, alongside, we evaluated how the same parameters responded to an OD withdrawal.
SUBJECTS: Thirty male 60-days-old Wistar rats were used.
METHODS: The control group (n = 10) was fed the control diet across the whole experiment. The remaining animals were fed a high-sugar/high-fat (HSHF) diet for 30 days (n = 20) and half of them were placed on the control diet for 48 h (n = 10) afterwards.
RESULTS: OD intake decreased hippocampal AMPK phosphorylation, although, it did not increase serum inflammation and only increased hippocampal pNFκBp65 levels without any increase in the cytokines assessed. Moreover, OD withdrawal led to higher inflammatory markers in the serum and hippocampus and higher hippocampal AMPK phosphorylation. The mediation models applied suggested that the effect of OD withdrawal on hippocampal inflammation was driven by serum inflammation, which activated the hippocampal IL10/AMPK anti-inflammatory pathway as a response.
CONCLUSION: Our analyses suggest that OD withdrawal increases serum inflammation with hippocampal consequent inflammatory alterations. Despite the general assumption that improving diet improves health, this may not be immediate.

Keywords:  AMPK; Hippocampus; Inflammation; Obesogenic diet; TNF-alpha; Withdrawal

DOI:  https://doi.org/10.1007/s00011-022-01632-9
Eur J Nutr. 2022 Sep 07.

Role of liver AMPK and GCN2 kinases in the control of postprandial protein metabolism in response to mid-term high or low protein intake in mice.

Tristan Chalvon-Demersay, Claire Gaudichon, Joanna Moro, Patrick C Even, Nadezda Khodorova, Julien Piedcoq, Benoit Viollet, Julien Averous, Anne-Catherine Maurin, Daniel Tomé, Marc Foretz, Pierre Fafournoux, Dalila Azzout-Marniche.

   PURPOSE: Protein synthesis and proteolysis are known to be controlled through mammalian target of rapamycin, AMP-activated kinase (AMPK) and general control non-derepressible 2 (GCN2) pathways, depending on the nutritional condition. This study aimed at investigating the contribution of liver AMPK and GCN2 on the adaptation to high variations in protein intake.
METHODS: To evaluate the answer of protein pathways to high- or low-protein diet, male wild-type mice and genetically modified mice from C57BL/6 background with liver-specific AMPK- or GCN2-knockout were fed from day 25 diets differing in their protein level as energy: LP (5%), NP (14%) and HP (54%). Two hours after a 1 g test meal, protein synthesis rate was measured after a 13C valine flooding dose. The gene expression of key enzymes involved in proteolysis and GNC2 signaling pathway were quantified.
RESULTS: The HP diet but not the LP diet was associated with a decrease in fractional synthesis rate by 29% in the liver compared to NP diet. The expression of mRNA encoding ubiquitin and Cathepsin D was not sensitive to the protein content. The deletion of AMPK or GCN2 in the liver did not affect nor protein synthesis rates and neither proteolysis markers in the liver or in the muscle, whatever the protein intake. In the postprandial state, protein level alters protein synthesis in the liver but not in the muscle.
CONCLUSIONS: Taken together, these results suggest that liver AMPK and GCN2 are not involved in this adaptation to high- and low-protein diet observed in the postprandial period.

Keywords:  High-protein diet; Knock-out mice; Liver; Low-protein diet; Protein synthesis; Proteolysis

DOI:  https://doi.org/10.1007/s00394-022-02983-z
Cells. 2022 Aug 25. pii: 2645. [Epub ahead of print]11(17):

Autophagy in Rat Müller Glial Cells Is Modulated by the Sirtuin 4/AMPK/mTOR Pathway and Induces Apoptosis under Oxidative Stress.

Mengqi Qin, Zhi Xie, Ting Cao, Zhiruo Wang, Xiaoyu Zhang, Feifei Wang, Wei Wei, Ming Jin, Jingyuan Ma, Ling Zeng, Yanan Wang, Shaonan Pei, Xu Zhang.

  Müller glial cells (MGCs) are a group of glial cells in the retina that provide essential support to retinal neurons; however, the understanding of MGC apoptosis and autophagy remains limited. This study was aimed at investigating the role of autophagy in MGCs under normal and oxidative conditions, and identifying the underlying mechanisms. In addition, the sirtuin 4 (SIRT4)-mediated signaling pathway was observed to regulate the autophagic process in MGCs. To assess the effect of autophagy on MGC mitochondrial function and survival, we treated rMC-1 cells-rat-derived Müller glial cells-with rapamycin and 3-methyladenine (3-MA), and found that MGC death was not induced by such treatment, while autophagic dysfunction could increase MGC apoptosis under oxidative stress, as reflected by the expression level of cleaved caspase 3 and PI staining. In addition, the downregulation of autophagy by 3-MA could influence the morphology of the mitochondrial network structure, the mitochondrial membrane potential, and generation of reactive oxygen species (ROS) under oxidative stress. Moreover, SIRT4 depletion enhanced autophagosome formation, as verified by an increase in the LC3 II/I ratio and a decrease in the expression of SQSTM1/p62, and vice versa. The inhibition of AMPK phosphorylation by compound C could reverse these changes in LC3 II/I and SQSTM1/p62 caused by SIRT4 knockdown. Our research concludes that MGCs can endure autophagic dysfunction in the absence of oxidative stress, while the downregulation of autophagy can cause MGCs to become more sensitized to oxidative stress. Simultaneous exposure to oxidative stress and autophagic dysfunction in MGCs can result in a pronounced impairment of cell survival. Mechanically, SIRT4 depletion can activate the autophagic process in MGCs by regulating the AMPK-mTOR signaling pathway.

Keywords:  Müller glial cell; SIRT4; apoptosis; autophagy; mitochondrial function

DOI:  https://doi.org/10.3390/cells11172645
FASEB J. 2022 Oct;36(10): e22531

Wnt inhibitory factor 1 ameliorated diabetic retinopathy through the AMPK/mTOR pathway-mediated mitochondrial function.

Jing Zou, Wei Tan, Kangcheng Liu, Bolin Chen, TianQi Duan, Huizhuo Xu.

  Diabetic retinopathy (DR) is one of the most common complications of diabetes mellitus and will lead to visual impairment. We aim to explore the effects and mechanisms of wnt inhibitory factor 1 (WIF1) in the progression of DR. To establish DR in vitro and in vivo, human retinal pigment epithelium (RPE) cell line ARPE-19 was treated with high-glucose (HG) and diabetic mice models were induced by streptozotocin (STZ), respectively. Different dose of recombinant WIF1 protein was used to treat DR. qRT-PCR and western blotting results demonstrated that WIF1 was downregulated, while VEGFA was upregulated in HG-induced ARPE-19 cells. WIF1 overexpression promoted cell migration. The ARPE-19 cells culture medium treated with WIF1 inhibited retinal endothelial cell tube formation and downregulated VEGFA expression. Moreover, WIF1 decreased the levels of ROS and MDA, while increasing the activity of SOD and GPX. WIF1 increased the ΔΨm in the mitochondria and downregulated the expression of mitochondrial autophagy-related proteins including Parkin, Pink1, LC3-II/LC3-I ratio, cleaved caspase 3, and cyt-c, which ameliorated mitochondrial dysfunction. The in vivo studies further demonstrated the consistent effects of WIF1 in STZ-induced mice. Taken together, WIF1 ameliorated mitochondrial dysfunction in DR by downregulating the AMPK/mTOR pathway.

Keywords:  AMPK/mTOR pathway; angiogenesis; diabetic retinopathy; mitochondrial dysfunction; wnt inhibitory factor 1

DOI:  https://doi.org/10.1096/fj.202200366RR
Br J Pharmacol. 2022 Sep 09.

Repurposing nitazoxanide as a novel anti-atherosclerotic drug based on mitochondrial uncoupling mechanisms.

Ming-Hui Ma, Feng-Feng Li, Wen-Feng Li, Hui Zhao, Man Jiang, Yuan-Yuan Yu, Yan-Chao Dong, Yi-Xin Zhang, Ping Li, Wen-Jie Bu, Zhi-Jie Sun, De-Li Dong.

   BACKGROUND AND PURPOSE: The anthelmintics nitazoxanide has mitochondrial uncoupling effect. Mitochondrial uncouplers have been proven to inhibit smooth muscle cell proliferation and migration, inhibit NLRP3 inflammasome activation of macrophages, and improve dyslipidemia, therefore, we aim to demonstrate that nitazoxanide would protect against atherosclerosis.
EXPERIMENTAL APPROACH: The mitochondrial oxygen consumption of cells was measured by using the high-resolution respirometry system Oxygraph-2K. The proliferation and migration of A10 cells were measured by using Edu immunofluorescence staining, wound-induced migration and Boyden chamber assay. Protein levels were measured by using western blot technique. ApoE (-/-) mice were fed with western diet (WD) to establish atherosclerotic model in vivo.
KEY RESULTS: The in vitro experiments showed that nitazoxanide and tizoxanide had mitochondrial uncoupling effect and activated cellular AMPK. Nitazoxanide and tizoxanide inhibited serum- and PDGF-induced proliferation and migration of A10 cells. Nitazoxanide and tizoxanide inhibited NLRP3 inflammasome activation in RAW264.7 macrophages and the mechanism by which involved AMPK/IκBα/NF-κB pathway. Nitazoxanide and tizoxanide also induced autophagy in A10 cells and RAW264.7 macrophages. The in vivo experiments demonstrated that oral administration of nitazoxanide reduced the increase of serum IL-1β and IL-6 level and suppressed atherosclerosis in western diet (WD)-fed ApoE (-/-) mice.
CONCLUSION AND IMPLICATIONS: Nitazoxanide inhibits the formation of atherosclerotic plaque in ApoE (-/-) mice fed with western diet. In view of nitazoxanide being an antiprotozoal drug approved by FDA, we propose it as a novel anti-atherosclerotic drug with clinical translational potential.

Keywords:  AMPK; Atherosclerosis; Nitazoxanide; Tizoxanide

DOI:  https://doi.org/10.1111/bph.15949
Int J Mol Sci. 2022 Sep 02. pii: 10042. [Epub ahead of print]23(17):

ASC Regulates Subcutaneous Adipose Tissue Lipogenesis and Lipolysis via p53/AMPKα Axis.

Hong Chen, Qilin Pei, Linfen Tao, Jing Xia, Guocai Lu, Ying Zong, Wenhua Xie, Wanqing Li, Chenglong Huang, Ting Zeng, Xinyu Yu, Weixuan Wang, Gaojun Chen, Song Yang, Rui Cheng, Xi Li.

  Obesity has become an extensive threat to human health due to associated chronic inflammation and metabolic diseases. Apoptosis-associated speck-like protein (ASC) is a critical link between inflammasome and apoptosis-inducing proteins. In this study, we aimed to clarify the role of ASC in lipid metabolism. With high-fat diet (HFD) and knockout leptin gene mice (ob/ob), we found that ASC expression in subcutaneous adipose tissue (SAT) correlated with obesity. It could also positively regulate the reprogramming of cellular energy metabolism. Stromal vascular fractions (SVF) cells derived from the SAT of Asc-/- mice or SVF from wild-type (WT) mice transfected with ASC siRNA were used to further investigate the underlying molecular mechanisms. We found ASC deficiency could lead to lipogenesis and inhibit lipolysis in SAT, aggravating lipid accumulation and impairing metabolic balance. In addition, our results showed that p53 and AMPKα expression were inhibited in SAT when ASC level was low. p53 and AMP-activated protein kinase α (AMPKα) were then assessed to elucidate whether they were downstream of ASC in regulating lipid metabolism. Our results revealed that ASC deficiency could promote lipid accumulation by increasing lipogenesis and decreasing lipolysis through p53/AMPKα axis. Regulation of ASC on lipid metabolism might be a novel therapeutic target for obesity.

Keywords:  AMPKα; ASC; lipogenesis; lipolysis; p53

DOI:  https://doi.org/10.3390/ijms231710042
Phytother Res. 2022 Sep 09.

Resveratrol reverses TGF-β1-mediated invasion and metastasis of breast cancer cells via the SIRT3/AMPK/autophagy signal axis.

Jia Wang, Ping Huang, Xiafang Pan, Chunhua Xia, Hong Zhang, Han Zhao, Zhao Yuan, Jianming Liu, Chao Meng, Fanglan Liu.

  Resveratrol (Resv) has antitumorigenic and antimetastatic activities; however, the molecular mechanisms underlying the inhibitory effects of Resv on the invasion and metastasis of breast cancer cells are still a subject of debate. In our study, we demonstrated that Resv inhibited tumor cell proliferation and tumor growth. It also suppressed invasion and pulmonary metastasis of breast cancer by reversing the transforming growth factor beta 1 (TGF-β1)-mediated EMT process. Meanwhile, the anticarcinogenic effects of Resv were abolished by the autophagy blocker 3-methyladenine (3-MA) or Beclin 1 small interfering RNA. Moreover, Resv upregulated autophagy-related genes and protein levels and induced the formation of autophagosomes in 4T1 breast cancer cells and xenograft mice, suggesting that autophagy was involved in the anticarcinogenic activities of Resv in both models. In addition, Resv-induced autophagy by increasing the expression of SIRT3 and phosphorylated AMPK. SIRT3 knockdown reduced AMPK phosphorylation and autophagy-related proteins levels, and suppressed the anticancer effects of Resv, demonstrating that the inhibitory effects of Resv on tumor progression were mediated via the SIRT3/AMPK/autophagy pathway. Taken together, our study provided novel insight into the anticancer effects of Resv and revealed that targeting the SIRT3/AMPK/autophagy pathway can serve as a new therapeutic target against breast cancer.

Keywords:  SIRT3; autophagy; breast cancer; epithelial-mesenchymal transition; resveratrol; tumor metastasis

DOI:  https://doi.org/10.1002/ptr.7608