bims-amsmem 2022-03-06 papers

bims-amsmem

Biomed News

on AMPK signaling mechanism in energy metabolism

Issue of 2022–03–06
34 papers selected by
Dipsikha Biswas, Københavns Universitet

The Role of AMP-activated Protein Kinase (AMPK) in Oxytosis/Ferroptosis: Protector or Potentiator?
CU06-1004 modulates the adenosine monophosphate (AMP)-associated protein kinase (AMPK) signaling pathway and inhibits lipogenesis in 3T3-L1 adipocytes and high-fat diet-induced obese mice.
Intestinal AMPK modulation of microbiota mediates crosstalk with brown fat to control thermogenesis.
miR-146a impedes the anti-aging effect of AMPK via NAMPT suppression and NAD+/SIRT inactivation.
Cyclic mechanical stretch regulates the AMPK/Egr1 pathway in tenocytes via Ca2+-mediated mechanosensing.
HA-20 prevents hepatocyte steatosis in metabolic-associated fatty liver disease via regulating Ca2+ relative signalling pathways.
Advanced Glycation End Products Induced Mitochondrial Dysfunction of Chondrocytes through Repression of AMPKα-SIRT1-PGC-1α Pathway.
Ca2+/calmodulin-dependent protein kinase II inhibition reduces myocardial fatty acid uptake and oxidation after myocardial infarction.
Administration of Gapmer-type Antisense Oligonucleotides Targeting γ-Glutamylcyclotransferase Suppresses the Growth of A549 Lung Cancer Xenografts.
Obesity induces resistance to central action of BMP8B through a mechanism involving the BBSome.
Impact of 5-HT7 receptor inverse agonism of lurasidone on monoaminergic tripartite synaptic transmission and pathophysiology of lower risk of weight gain.
4-Octyl Itaconate Prevents Free Fatty Acid-Induced Lipid Metabolism Disorder through Activating Nrf2-AMPK Signaling Pathway in Hepatocytes.
LKB1 alleviates high glucose‑ and high fat‑induced inflammation and the expression of GnRH and sexual precocity‑related genes, in mouse hypothalamic cells by activating the AMPK/FOXO1 signaling pathway.
sSTEAP4 regulates cellular homeostasis and improves high-fat-diet-caused oxidative stress in hepatocytes.
Vitamin E rescues valproic acid-induced testicular injury in rats: Role of autophagy.
Hesperidin attenuates hepatic lipid accumulation in mice fed high-fat diet and oleic acid induced HepG2 via AMPK activation.
Cordycepin alleviates myocardial ischemia/reperfusion injury by enhancing autophagy via AMPK-mTOR pathway.
CARM1 promotes gastric cancer progression by regulating TFE3 mediated autophagy enhancement through the cytoplasmic AMPK-mTOR and nuclear AMPK-CARM1-TFE3 signaling pathways.
Metformin reduces chondrocyte pyroptosis in an osteoarthritis mouse model by inhibiting NLRP3 inflammasome activation.
Changes in Skeletal Muscle PAK1 Levels Regulate Tissue Crosstalk to Impact Whole Body Glucose Homeostasis.
Metformin enhances LDL-cholesterol uptake by suppressing the expression of the pro-protein convertase subtilisin/kexin type 9 (PCSK9) in liver cells.
Co-delivery of EGCG and lycopene via a pickering double emulsion induced synergistic hypolipidemic effect.
D-allulose ameliorates adiposity through the AMPK-SIRT1-PGC-1α pathway in HFD-induced SD rats.
Disruption of polycystin-1 cleavage leads to cardiac metabolic rewiring in mice.
P2Y1R Ligation Suppresses Th17 Cell Differentiation and Alleviates Colonic Inflammation in an AMPK-Dependent Manner.
Metformin Alleviates Autistic-Like Behaviors Elicited by High-Fat Diet Consumption and Modulates the Crosstalk Between Serotonin and Gut Microbiota in Mice.
HRAS germline mutations impair LKB1/AMPK signaling and mitochondrial homeostasis in Costello syndrome models.
Dietary fibers with different viscosity regulate lipid metabolism via ampk pathway: roles of gut microbiota and short-chain fatty acid.
PP2A activation targets AML stem cells.
Maturation of beta cells: lessons from in vivo and in vitro models.
Exercise activates autophagy and regulates endoplasmic reticulum stress in muscle of high-fat diet mice to alleviate insulin resistance.
Acacetin ameliorates cardiac hypertrophy by activating Sirt1/AMPK/PGC-1α pathway.
Moderate L-lactate administration suppresses adipose tissue macrophage M1 polarization to alleviate obesity-associated insulin resistance.
NF-κB and AMPK-Nrf2 pathways support the protective effect of polysaccharides from Polygonatum cyrtonema Hua in lipopolysaccharide-induced acute lung injury.

Antioxid Redox Signal. 2022 Mar 04.

The Role of AMP-activated Protein Kinase (AMPK) in Oxytosis/Ferroptosis: Protector or Potentiator?

Antonio Currais, Devin Kepchia, Zhibin Liang, Pamela Maher.

SIGNIFICANCE: Evidence for a role for the oxytosis/ferroptosis regulated cell death pathway in aging and neurodegenerative diseases has been growing over the past few years. Because of this, there is an increasing necessity to identify endogenous signaling pathways that can be modulated to protect cells from this form of cell death. Recent Advances: Recently, several studies have identified a protective role for the AMP-activated protein kinase (AMPK)/acetyl CoA carboxylase 1 (ACC1) pathway in oxytosis/ferroptosis. However, there are also a number of studies suggesting that this pathway contributes to cell death initiated by various inducers of oxytosis/ferroptosis.
CRITICAL ISSUES: The goals of this review are to provide an overview and analysis of the published studies and highlight specific areas where more research is needed.
FUTURE DIRECTIONS: Much remains to be learned about AMPK signaling in oxytosis/ferroptosis especially the conditions where it is protective. Furthermore, the role of AMPK signaling in the brain and especially the aging brain needs further investigation.

DOI: https://doi.org/10.1089/ars.2022.0013
Life Sci. 2022 Feb 28. pii: S0024-3205(22)00140-0. [Epub ahead of print] 120440

CU06-1004 modulates the adenosine monophosphate (AMP)-associated protein kinase (AMPK) signaling pathway and inhibits lipogenesis in 3T3-L1 adipocytes and high-fat diet-induced obese mice.

Cho-Rong Bae, Young-Guen Kwon.

   AIMS: The endothelial dysfunction blocker CU06-1004 exhibits anti-inflammatory effects in chronic diseases. Obesity is a major cause of chronic inflammation, and the effect of CU06-1004 on obesity has not been studied yet. Therefore, in this study, we investigated the anti-obesity properties of CU06-1004 in 3T3-L1 adipocytes and high-fat diet-induced obese mice.
METHODS: Differentiated 3T3-L1 adipocytes were treated with various concentrations of CU06-1004 (0-20 μg/mL) and subjected to Oil Red O staining to determine the levels of lipid droplet and intracellular triglyceride accumulation. Additionally, high-fat diet-induced obese C57BL/6J mice were administered with a low (10 mg/kg/day) or high (20 mg/kg/day) oral dose of CU06-1004. Finally, the expressions of genes and proteins involved in the adenosine monophosphate (AMP)-activated protein kinase (AMPK) signaling pathway were assessed by real-time polymerase chain reaction and Western blot, respectively.
KEY FINDINGS: The CU06-1004 administration reduced lipid accumulation in the 3T3-L1 adipocytes by inhibiting the expressions of peroxisome proliferator-activated receptor gamma, CCAAT/enhancer-binding protein alpha, fatty acid binding protein 4, and fatty acid synthase in a dose-dependent manner. Additionally, it significantly increased the phosphorylation of AMPKα and acetyl-CoA carboxylase in the 3T3-L1 adipocytes. An oral administration of high dose of CU06-1004 in the obese mice significantly decreased their body weight and the mesenteric white adipose tissue weight. Furthermore, CU06-1004 improved hepatic steatosis by reducing lipogenesis, besides improving insulin resistance and exerting systemic anti-inflammatory effects.
SIGNIFICANCE: Therefore, CU06-1004 may have therapeutic potential in the prevention of obesity and obesity-related disorders.

Keywords:  CU06-1004; High-fat diet; Insulin resistance; Lipogenesis; Mesenteric white adipose tissue; Obesity

DOI:  https://doi.org/10.1016/j.lfs.2022.120440
Nat Commun. 2022 Mar 03. 13(1): 1135

Intestinal AMPK modulation of microbiota mediates crosstalk with brown fat to control thermogenesis.

Eryun Zhang, Lihua Jin, Yangmeng Wang, Jui Tu, Ruirong Zheng, Lili Ding, Zhipeng Fang, Mingjie Fan, Ismail Al-Abdullah, Rama Natarajan, Ke Ma, Zhengtao Wang, Arthur D Riggs, Sarah C Shuck, Li Yang, Wendong Huang.

The energy-dissipating capacity of brown adipose tissue through thermogenesis can be targeted to improve energy balance. Mammalian 5'-AMP-activated protein kinase, a key nutrient sensor for maintaining cellular energy status, is a known therapeutic target in Type II diabetes. Despite its well-established roles in regulating glucose metabolism in various tissues, the functions of AMPK in the intestine remain largely unexplored. Here we show that AMPKα1 deficiency in the intestine results in weight gain and impaired glucose tolerance under high fat diet feeding, while metformin administration fails to ameliorate these metabolic disorders in intestinal AMPKα1 knockout mice. Further, AMPKα1 in the intestine communicates with brown adipose tissue to promote thermogenesis. Mechanistically, we uncover a link between intestinal AMPKα1 activation and BAT thermogenic regulation through modulating anti-microbial peptide-controlled gut microbiota and the metabolites. Our findings identify AMPKα1-mediated mechanisms of intestine-BAT communication that may partially underlie the therapeutic effects of metformin.

DOI: https://doi.org/10.1038/s41467-022-28743-5
Signal Transduct Target Ther. 2022 Mar 04. 7(1): 66

miR-146a impedes the anti-aging effect of AMPK via NAMPT suppression and NAD+/SIRT inactivation.

Hui Gong, Honghan Chen, Peng Xiao, Ning Huang, Xiaojuan Han, Jian Zhang, Yu Yang, Tiepeng Li, Tingting Zhao, Haoran Tai, Weitong Xu, Gongchang Zhang, Chuhui Gong, Ming Yang, Xiaoqiang Tang, Hengyi Xiao.

Nicotinamide adenine dinucleotide (NAD+) is indispensable for the anti-aging activity of the sirtuin (SIRT) family enzymes. AMP-activated protein kinase (AMPK) upregulates NAD+ synthesis and SIRT activity in a nicotinamide phosphoribosyltransferase (NAMPT)-dependent manner. However, the molecular mechanisms that affect AMPK-driven NAMPT expression and NAD+/SIRT activation remain unclear. In this study, we tried to identify senescence-associated microRNAs (miRNAs) that negatively regulate the cascade linking AMPK and NAMPT expression. miRNA-screening experiments showed that the expression of miR-146a increased in senescent cells but decreased following AMPK activation. Additionally, miR-146a overexpression weakened the metformin-mediated upregulation of NAMPT expression, NAD+ synthesis, SIRT activity, and senescence protection, whereas treatment with the miR-146a inhibitor reversed this effect. Importantly, these findings were observed both in vitro and in vivo. Mechanistically, miR-146a directly targeted the 3'-UTR of Nampt mRNA to reduce the expression of NAMPT. AMPK activators metformin and 5-aminoimidazole-4-carboxamide (AICAR) hindered miR-146a expression at the transcriptional level by promoting IκB kinase (IKK) phosphorylation to attenuate nuclear factor-kappaB (NF-κB) activity. These findings identified a novel cascade that negatively regulates the NAD+/SIRT pathway by suppressing miR-146a-mediated NAMPT downregulation. Furthermore, our results showed that miR-146a impedes the anti-aging effect of AMPK. This mutual inhibitory relationship between miR-146a and AMPK enriches our understanding of the molecular connections between AMPK and SIRT and provides new insight into miRNA-mediated NAD+/SIRT regulation and an intervention point for the prevention of aging and age-related diseases.

DOI: https://doi.org/10.1038/s41392-022-00886-3
Connect Tissue Res. 2022 Mar 01. 1-13

Cyclic mechanical stretch regulates the AMPK/Egr1 pathway in tenocytes via Ca2+-mediated mechanosensing.

Yu-Ting Huang, Yu-Fu Wu, Hsing-Kuo Wang, Chung-Chen Jane Yao, Yi-Heng Chiu, Jui-Sheng Sun, Yuan-Hung Chao.

   PURPOSE: Mechanical stimuli are essential for the maintenance of tendon tissue homeostasis. The study aims to elucidate the mechanobiological mechanisms underlying the maintenance of tenocyte homeostasis by cyclic mechanical stretch under high-glucose (HG) condition.
MATERIALS AND METHODS: Primary tenocytes were isolated from rat Achilles tendon and 2D-cultured under HG condition. The in vitro effects of a single bout, 2-h cyclic biaxial stretch session (1 Hz, 8%) on primary rat tenocytes were explored through Flexcell system. Cell viability, tenogenic gene expression, intracellular calcium concentration, focal adhesion kinase (FAK) expression, and signaling pathway activation were analyzed in tenocytes with or without mechanical stretch.
RESULTS: Mechanical stretch increased tenocyte proliferation and upregulated early growth response protein 1 (Egr1) expression. An increase in intracellular calcium was observed after 30 min of stretching. Mechanical stretch phosphorylated FAK, calmodulin-dependent protein kinase kinase 2 (CaMKK2), and 5' adenosine monophosphate-activated protein kinase (AMPK) in a time-dependent manner, and these effects were abrogated after blocking intracellular calcium. Inhibition of FAK, CaMKK2, and AMPK downregulated the expression of Egr1. In addition, mechanical stretch reinforced cytoskeletal organization via calcium (Ca2+)/FAK signaling.
CONCLUSIONS: Our study demonstrated that mechanical stretch-induced calcium influx activated CaMKK2/AMPK signaling and FAK-cytoskeleton reorganization, thereby promoting the expression of Egr1, which may help maintain tendon cell characteristics and homeostasis in the context of diabetic tendinopathy.

Keywords:  AMPK; Egr1; Tendon; diabetic tendinopathy; intracellular calcium; mechanotransduction

DOI:  https://doi.org/10.1080/03008207.2022.2044321
Eur J Pharmacol. 2022 Feb 23. pii: S0014-2999(22)00099-1. [Epub ahead of print] 174838

HA-20 prevents hepatocyte steatosis in metabolic-associated fatty liver disease via regulating Ca2+ relative signalling pathways.

Jie Wang, Ming-Ming Du, Yun Du, Jian-Xin Li.

  Metabolic-associated fatty liver disease (MAFLD) is caused by hepatocyte steatosis and is associated with obesity, type II diabetes, and heart disease. There are currently no effective drugs to treat MAFLD. This study explored the effect of HA-20, an oleanolic acid derivative, on hepatocyte steatosis in MAFLD. HepG2, L02, and AML12 cells were developed using oleic acid for in vitro MAFLD cell assays, and a high-fat diet + high-fructose diet-induced (HFHF) MAFLD mouse model was established for in vivo studies. The results demonstrated that HA-20 prevented hepatocyte steatosis in cell assays and caused 26.3, 57.7 and 70.0% inhibition of triglyceride (TG) levels in the 5.0, 10.0 and 20.0 μM HA-20 groups, respectively. The EC50 values of HA-20 treatment in HepG2, L02 and AML12 cells were 9.7 ± 0.6 μM, 42.4 ± 3.5 μM and 71.0 ± 14.7 μM, respectively. HA-20 also prevented hepatocyte steatosis in the MAFLD mouse model, the liver triglyceride contents were 2.3 ± 0.4 and 1.5 ± 0.2 mmol/L in the 2.5 and 5.0 mg/kg/day HA-20 groups, lower than 6.2 ± 0.7 mmol/L in the HFHF group and 3.3 ± 0.4 mmol/L in the metformin group. Further mechanistic investigation revealed that HA-20 increased the phosphorylation of calmodulin-dependent protein kinase kinase (p-CaMKK) and the phosphorylation of AMP-activated protein kinase (p-AMPK), at least partially by increasing intracellular Ca2+ concentration, which suppressed lipogenesis and enhanced β-oxidation. Our findings provide new insight into preventing MAFLD by increasing Ca2+ and suggest that HA-20 possesses therapeutic potential for MAFLD management.

Keywords:  AMPK; Ca(2+); HA-20; Hepatocyte steatosis; MAFLD

DOI:  https://doi.org/10.1016/j.ejphar.2022.174838
Pharmacology. 2022 Mar 03. 1-10

Advanced Glycation End Products Induced Mitochondrial Dysfunction of Chondrocytes through Repression of AMPKα-SIRT1-PGC-1α Pathway.

Qingshan Yang, Yucong Shi, Tao Jin, Bowen Duan, Shujin Wu.

   INTRODUCTION: Our previous studies have demonstrated advanced glycation end products (AGEs) was an important mediator in osteoarthritis (OA) which may induce mitochondrial dysfunction. AMP-activated protein kinase (AMPK), sirtuin 1 (SIRT1), and its downstream target peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α) are the critical sensors that regulate mitochondrial biogenesis and have been recognized as therapeutic targets in OA. This study was designed to test whether AGEs caused mitochondrial dysfunction through modulation of AMPKα/SIRT1/PGC-1α.
METHODS: We knocked down or overexpressed AMPKα, SIRT1, and PGC-1α by small interfering RNA or plasmid DNA transfection, respectively. Mitochondrial membrane potential (△Ψ) was detected by tetraethylbenzimidazolyl carbocyanine iodide (JC-1) fluorescence probe.
RESULTS: The results showed that AGEs impaired △Ψ, intracellular ATP level, and mitochondrial DNA content, linked to decreased AMPKα, SIRT1, and PGC-1α expression in chondrocyte. AMPKα pharmacologic activation or overexpression of AMPKα, SIRT1, and PGC-1α reversed impairments of mitochondrial biogenesis, oxidative stress, and inflammation in AGEs-induced chondrocytes. However, AMPKα activation using AICAR had decreased capacity to increase each of those same effect readouts in AGEs-treated SIRT1-siRNA or PGC-1α-siRNA chondrocyte.
CONCLUSION: Taken together, AGEs reduced the AMPKα/SIRT1/PGC-1α signaling in chondrocytes, leading to mitochondrial dysfunction as a result of increased oxidative stress, inflammation, and apoptosis. These results indicated that target AMPK may be as a novel therapeutic strategy for AGEs-related OA prevention.

Keywords:  AMP-activated protein kinase; Advanced glycation end products; Mitochondrial dysfunction; Peroxisome proliferator-activated receptor gamma coactivator-1α; Sirtuin 1

DOI:  https://doi.org/10.1159/000521720
Biochim Biophys Acta Mol Cell Biol Lipids. 2022 Feb 26. pii: S1388-1981(22)00010-5. [Epub ahead of print]1867(6): 159120

Ca2+/calmodulin-dependent protein kinase II inhibition reduces myocardial fatty acid uptake and oxidation after myocardial infarction.

Yidi Meng, Peiwu Ding, Hongfei Wang, Xueke Yang, Zhiyu Wang, Daan Nie, Jie Liu, Yun Huang, Guanhua Su, Jun Hu, Yanwen Su, Xinling Du, Nianguo Dong, Haibo Jia, Hongbing Zhang, Jiaming Zhang, Jingdong Li.

  An AMP-activated kinase (AMPK) signaling pathway is activated during myocardial ischemia and promotes cardiac fatty acid (FA) uptake and oxidation. Similarly, the multifunctional Ca2+/calmodulin-dependent protein kinase II (CaMKII) is also triggered by myocardial ischemia, but its function in FA metabolism remains unclear. Here, we explored the role of CaMKII in FA metabolism during myocardial ischemia by investigating the effects of cardiac CaMKII on AMPK-acetyl-CoA carboxylase (ACC), malonyl CoA decarboxylase (MCD), and FA translocase cluster of differentiation 36 (FAT/CD36), as well as cardiac FA uptake and oxidation. Moreover, we tested whether CaMKII and AMPK are binding partners. We demonstrated that diseased hearts from patients with terminal ischemic heart disease displayed increased phosphorylation of CaMKII, AMPK, and ACC and increased expression of MCD and FAT/CD36. AC3-I mice, which have a genetic myocardial inhibition of CaMKII, had reduced gene expression of cardiac AMPK. In post-MI (myocardial infarction) AC3-I hearts, AMPK-ACC phosphorylation, MCD and FAT/CD36 levels, cardiac FA uptake, and FA oxidation were significantly decreased. Notably, we demonstrated that CaMKII interacted with AMPK α1 and α2 subunits in the heart. Additionally, AC3-I mice displayed significantly less cardiac hypertrophy and apoptosis 2 weeks post-MI. Overall, these findings reveal a unique role for CaMKII inhibition in repressing FA metabolism by interacting with AMPK signaling pathways, which may represent a novel mechanism in ischemic heart disease.

Keywords:  AMP-activated kinase (AMPK); Acetyl-CoA carboxylase (ACC); Ca(2+)/calmodulin-dependent protein kinase II (CaMKII); FA translocase cluster of differentiation 36 (FAT/CD36); Fatty acid metabolism; Ischemic heart disease

DOI:  https://doi.org/10.1016/j.bbalip.2022.159120
Anticancer Res. 2022 03;42(3): 1221-1227

Administration of Gapmer-type Antisense Oligonucleotides Targeting γ-Glutamylcyclotransferase Suppresses the Growth of A549 Lung Cancer Xenografts.

Hiromi Ii, Yuuya Kasahara, Harumi Yamaguma, Susumu Kageyama, Akihiro Kawauchi, Satoshi Obika, Susumu Nakata.

   BACKGROUND/AIM: γ-Glutamyl cyclotransferase (GGCT) is up-regulated in various cancer types, including lung cancer. In this study, we evaluated efficacy of gapmer-type antisense oligonucleotides (ASOs) targeting GGCT in an A549 lung cancer xenograft mouse model and studied their mechanisms of action.
MATERIALS AND METHODS: GGCT was inhibited using GGCT-ASOs and cell proliferation was evaluated by dye exclusion test. Western blot analysis was conducted to measure expression of GGCT, p21, p16 and p27, phosphorylation of AMP-activated protein kinase, and caspase activation in A549 cells. Induction of apoptosis and up-regulation of reactive oxygen species were assessed by flow cytometry using annexin V staining and 2',7'-dichlorodihydrofluorescein diacetate dye, respectively.
RESULTS: GGCT-ASOs suppressed GGCT expression in A549 cells, inhibited proliferation, and induced apoptosis with activation of caspases. GGCT-ASOs also increased expression of cell-cycle regulating proteins, phospho-AMPK and ROS levels. Systemic administration of GGCT-ASOs to animals bearing A549 lung cancer xenografts showed significant antitumor effects without evident toxicity.
CONCLUSION: GGCT-ASOs appear to be promising as novel cancer therapeutic agents.

Keywords:  AMPK; antisense; cyclin-dependent kinase inhibitor; lung cancer; reactive oxygen species; γ-glutamylcyclotransferase

DOI:  https://doi.org/10.21873/anticanres.15589
Mol Metab. 2022 Feb 23. pii: S2212-8778(22)00034-5. [Epub ahead of print] 101465

Obesity induces resistance to central action of BMP8B through a mechanism involving the BBSome.

Eva Rial-Pensado, Oscar Freire-Agulleiro, Marcos Ríos, Deng Fu Guo, Cristina Contreras, Patricia Seoane-Collazo, Sulay Tovar, Rubén Nogueiras, Carlos Diéguez, Kamal Rahmouni, Miguel López.

   OBJECTIVE: Bone morphogenetic protein 8B (BMP8B) plays a major role in the regulation of energy homeostasis by modulating brown adipose tissue (BAT) thermogenesis and white adipose tissue (WAT) browning. Here, we investigated whether BMP8B role in metabolism is affected by obesity and the possible molecular mechanisms underlying that action.
METHODS: Central treatments with BMP8B were performed in rats fed standard (SD) and high fat diet (HFD), as well as in genetic modified mice. Energy balance studies, infrared thermographic analysis of BAT and molecular analysis of the hypothalamus, BAT and WAT were carried out.
RESULTS: We show for the first time that HFD-induced obesity elicits resistance to the central actions of BMP8B on energy balance. This obesity-induced BMP8B resistance is explained by i) lack of effects on AMP-activated protein kinase (AMPK) signaling, ii) decreased BMP receptors signaling and iii) reduced expression of Bardet-Biedl Syndrome 1 (BBS1) protein, a key component of the protein complex BBSome, in the ventromedial nucleus of the hypothalamus (VMH). The possible mechanistic involvement of BBS1 in this process is demonstrated by lack of central response to BMP8B in mice carrying a single missense disease-causing mutation in the Bbs1 gene.
CONCLUSIONS: Overall, our data uncover a new mechanism of central resistance to hormonal action that may be of relevance in the pathophysiology of obesity.

Keywords:  AMPK; BAT; BBS1; BMP8B; hypothalamus; obesity

DOI:  https://doi.org/10.1016/j.molmet.2022.101465
Biomed Pharmacother. 2022 Feb 24. pii: S0753-3322(22)00138-X. [Epub ahead of print]148 112750

Impact of 5-HT7 receptor inverse agonism of lurasidone on monoaminergic tripartite synaptic transmission and pathophysiology of lower risk of weight gain.

Kouji Fukuyama, Eishi Motomura, Takashi Shiroyama, Motohiro Okada.

  A part of atypical antipsychotics exert mood-stabilising effects via modulation of various monoamine receptors and intracellular signalling. Recent pharmacodynamic studies suggested that tripartite-synaptic transmission can be involved in pathophysiology of mood-disorders, schizophrenia, their associated cognitive impairments, and several adverse-reactions to atypical antipsychotics. Therefore, to explore mechanisms underlying antidepressive mood-stabilising and antipsychotic effects of lurasidone, we determined concentration-dependent effects of acute and subchronic lurasidone administrations on astroglial L-glutamate release, and expression of connexin43, ERK, AKT, adenosine monophosphate activated protein kinase (AMPK), 5-HT1A (5-HT1AR) and 5-HT7 (5-HT7R) receptors in cultured astrocytes using ultra-high-pressure liquid-chromatography with mass-spectrometry and capillary-immunoblotting systems. Therapeutically-relevant lurasidone concentration suppressed astroglial L-glutamate release through activated connexin43-containing hemichannel by decreasing connexin43 expression in plasma-membrane. Subchronic lurasidone administration downregulated 5-HT1AR and 5-HT7R in astroglial plasma-membrane concentration-dependently. Subchronic lurasidone administration attenuated ERK and AMPK signallings concentration-dependently without affecting AKT signalling. These results suggest that effects of subchronic lurasidone administration on astroglial L-glutamate release, 5-HT receptor, and intracellular signalling are similar to vortioxetine and different from mood-stabilising atypical antipsychotics, clozapine. Therefore, inhibitory effects of subchronic lurasidone administration on astroglial L-glutamate release through activated connexin43-containing hemichannel probably contribute to pathophysiology of antidepressive mood-stabilising effects of lurasidone. Furthermore, inhibitory effects of subchronic lurasidone administration on ERK and AMPK activities (without affecting AKT activity) induced by downregulation of 5-HT7R could result in clinical advantages of lurasidone, lower risk of weight gain.

Keywords:  AKT; AMPK; Astrocyte; Connexin43; ERK; Glutamate; Lurasidone

DOI:  https://doi.org/10.1016/j.biopha.2022.112750
Oxid Med Cell Longev. 2022 ;2022 5180242

4-Octyl Itaconate Prevents Free Fatty Acid-Induced Lipid Metabolism Disorder through Activating Nrf2-AMPK Signaling Pathway in Hepatocytes.

Xu Chu, Longlong Li, Weiyuan Yan, Haitian Ma.

Nonalcoholic fatty liver disease (NAFLD), characterized with oxidative stress and hepatic steatosis, is a serious threat to human health. As a specific activator of nuclear factor E2-related factor 2 (Nrf2), the 4-octyl itaconate (4-OI) has the beneficial effects in antioxidant and anti-inflammation; however, whether 4-OI can alleviate hepatic steatosis and its mechanism is still unknown. The present study was aimed at investigating the protective effects of 4-OI on free fat acid- (FFA-) induced lipid metabolism disorder and its potential molecular mechanism in hepatocytes. The results showed that 4-OI treatment markedly alleviated FFA-induced oxidative stress and excessive lipid accumulation in hepatocytes. Mechanistically, 4-OI significantly suppressed the overproduction of reactive oxygen species (ROS) through activation of Nrf2; the downregulation of ROS level induced a downregulation of AMP-dependent protein kinase (AMPK) phosphorylation level which finally ameliorated excessive lipid accumulation in FFA-stimulated hepatocytes. In general, our data demonstrated that 4-OI relieves the oxidative stress and lipid metabolism disorder in FFA-stimulated hepatocytes; and these beneficial effects were achieved by activating the Nrf2-AMPK signaling pathway. These data not only expand the new biological function of 4-OI but also provide a theoretical basis for 4-OI to protect against lipid metabolism disorders and related diseases, such as NAFLD.

DOI: https://doi.org/10.1155/2022/5180242
Mol Med Rep. 2022 Apr;pii: 143. [Epub ahead of print]25(4):

LKB1 alleviates high glucose‑ and high fat‑induced inflammation and the expression of GnRH and sexual precocity‑related genes, in mouse hypothalamic cells by activating the AMPK/FOXO1 signaling pathway.

Hui Liu, Limei Guan, Qing Zhou, Hailong Huang, Liangpu Xu.

  Precocious puberty (PP) is a developmental disorder. Hypothalamic cells can produce gonadotropin‑releasing hormone (GnRH), the final output of neuroendocrine regulation that occurs during puberty. The aim of the present study was to investigate the role of live kinase B1 (LKB1), also known as serine/threonine kinase, in the progression of PP and identify the underlying mechanisms. First, the levels of LKB1 in peripheral blood and peripheral blood mononuclear cells of children with PP were detected by reverse transcription‑quantitative (RT‑q) PCR or western blotting. After the GT1‑7 mouse hypothalamus cell line was treated with high glucose (HG) and high fat (HF), the expression of LKB1 and GnRH was tested. LKB1 was overexpressed by transfection with a pcDNA3.1 plasmid and the levels of inflammatory factors, GnRH, PP‑related factors and proteins in the AMP‑activated protein kinase (AMPK)/forkhead box protein O1 (FOXO1) pathway were determined using RT‑qPCR or western blot analysis. Subsequently, Compound C, an inhibitor of AMPK/FOXO1 signaling, was used to clarify whether the effects of LKB1 on PP were mediated by the regulation of this pathway. Results indicated that children with PP exhibited a lower LKB1 expression. In addition, HG and HF culture resulted in an enhanced GnRH expression and a reduced LKB1 expression in GT1‑7 cells. LKB1 overexpression inhibited the contents of TNF‑α, IL‑6 and GnRH in in GT1‑7 cells exposed to HG and HF and reduced the expression of PP‑related proteins, including estrogen receptor‑β, cluster of differentiation 36 and G‑protein‑coupled receptor. In addition, the expression of phosphorylated (p)‑AMPK and p‑FOXO1 was markedly downregulated following LKBI overexpression. Furthermore, compound C intervention partially diminished the inhibitory effects of LKB1‑mediated upregulation on the levels of inflammation and PP‑related factors. In conclusion, these results demonstrated that LKB1 alleviated HG‑ and HF‑induced inflammation, as well as the expression of GnRH and sexual precocity‑related genes, in GT1‑7 cells by activating the AMPK/FOXO1 signaling pathway.

Keywords:  AMP‑activated protein kinase; gonadotropin‑releasing hormone; inflammation; live kinase B1; pubertas praecox

DOI:  https://doi.org/10.3892/mmr.2022.12659
Life Sci. 2022 Feb 25. pii: S0024-3205(22)00138-2. [Epub ahead of print]296 120438

sSTEAP4 regulates cellular homeostasis and improves high-fat-diet-caused oxidative stress in hepatocytes.

Lin Zhu, Bin Li, Dongqin Chen, Ning Chen, Le Xu, Qinjin Li, Xiaodong Chen.

   AIM: Nonalcoholic fatty liver disease (NAFLD) has become a global epidemic, but its pathogenesis is unclear. STEAP4, a member of six transmembrane protein family, integrates inflammatory and metabolic responses. Our present aim is to explore the roles of STEAP4 in maintaining cellular homeostasis and improving high-fat-diet (HFD)-caused oxidative stress in hepatocytes.
MAIN METHODS: NAFLD model was established by HFD-feeding mice. The effects of over-nutrition on liver were detected by serum biochemical analysis and bulk RNA-seq. The levels of gene expression were measured by QPCR and Western Blot. Immunofluorescent staining was applied to determine the localization of STEAP4. AMPK agonist was employed to investigate the link between STEAP4 and AMPK pathway.
KEY FINDINGS: Sus scrofa STEAP4 (sSTEAP4) relieved oxidative stress and rescued the viability of hepatocytes. sSTEAP4 increased AKT phosphorylation and SOD2 level in hepatocytes, whether or not treated with H2O2, suggesting sSTEAP4 has regulatory effects on insulin signaling and antioxidant pathways. However, sSTEAP4 inhibited AMPK phosphorylation and Beclin1/LC3 expression under H2O2-deficiency situation, but the results were conversed with H2O2 stimulation. The cellular ER stress was aggravated with the increased energy during oxidative stress, indicating that sSTEAP4 might regulate the energetic communication between ER and mitochondria by intervening mitochondrial energy production. In addition, sSTEAP4 was demonstrated to localize in the membranes of plasma and ER in HepG2 hepatocytes.
SIGNIFICANCE: Our results reveal that sSTEAP4 based on the needs of cell itself to improve hepatic oxidative stress and HFD-caused NAFLD, which might provide a new therapeutic scheme for NAFLD.

Keywords:  AMPK; ER stress; Energy metabolism; PERK; STEAP4

DOI:  https://doi.org/10.1016/j.lfs.2022.120438
Life Sci. 2022 Feb 25. pii: S0024-3205(22)00134-5. [Epub ahead of print] 120434

Vitamin E rescues valproic acid-induced testicular injury in rats: Role of autophagy.

Amira Ebrahim Alsemeh, Marwa Mahmood Ahmed, Amal Fawzy, Walaa Samy, Marwa Tharwat, Samar Rezq.

   AIMS: Valproic acid (VPA), a commonly used antiepileptic drug, can induce testicular oxidative stress and injury. Altered autophagic response usually follows testicular injury. The study aims to evaluate the role of autophagy in the protective effect of the antioxidant Vitamin E (Vit E) against VPA-induced testicular injury.
MATERIALS AND METHODS: VPA (100, 300, and 500 mg/kg/day) was administered for 8 days. The protective group received both Vit E (50 mg/kg) and VPA (500 mg/kg). The testicular weight, sperm analysis, and serum testosterone concentration, as well as testicular histopathology, steroidogenic gene expression, and oxidative stress markers were evaluated. The mRNA or protein expression of autophagy-related proteins [adenosine monophosphate-activated protein kinase (AMPK), mammalian target of rapamycin (mTOR), microtubule-associated protein light chain 3 (LC3), Beclin1, and p62] were measured using RT-PCR or immunohistochemistry.
KEY FINDINGS: VPA resulted in lower testes weight and sperm quality with aberrant morphology. VPA dose-dependently induced testicular oxidative stress, which was associated with decreased steroidogenic gene expression and serum testosterone levels, as well as deteriorated histopathology. These biochemical and histological changes were also associated with autophagy induction (higher LC3 and Beclin1 and lower p62) that was lost with the highest toxic dose (500 mg/kg). The attenuated autophagy with the highest dose was accompanied by AMPK downregulation and mTOR upregulation. Vit E protected against VPA-mediated oxidative stress and toxicity while also restoring autophagic response and AMPK/mTOR levels.
SIGNIFICANCE: The study highlights vitamin E as a valuable protective asset against VPA-induced testicular injury, possibly through AMPK-mTOR-dependent autophagy induction.

Keywords:  Autophagy; Steroidogenesis; Testicular injury; Valproic acid; Vitamin E

DOI:  https://doi.org/10.1016/j.lfs.2022.120434
Life Sci. 2022 Feb 23. pii: S0024-3205(22)00128-X. [Epub ahead of print]296 120428

Hesperidin attenuates hepatic lipid accumulation in mice fed high-fat diet and oleic acid induced HepG2 via AMPK activation.

Hao Chen, Tong Nie, Penglu Zhang, Jun Ma, Anshan Shan.

   AIMS: In recent years, more and more people are suffering from lifestyle-related disease such as nonalcoholic fatty liver disease (NAFLD) because of unhealthy diet and lack of physical exercise. Hesperidin (HDN) is a flavonoid found in high concentrations in citrus fruits. In this study, we investigated the effect of HDN on NAFLD, providing information to develop dietary supplements for NAFLD treatment and prevention.
MATERIALS AND METHODS: Testing kits, hematoxylin-eosin staining, oil red O staining, western blot, immunofluorescence, cck-8 assay, and blood biochemical analysis were carried out during the experiments in vivo and in vitro.
KEY FINDINGS: The current study revealed that HDN significantly reduced liver index and serum lipid levels, and protected against liver steatosis and injury induced by HFD. In addition, HDN suppressed oil acid induced intracellular lipid accumulation in HepG2 cells. Moreover, HDN increased the expression level of pAMPK and downregulated SREBP-1C, ACC and FAS expression in vivo and in vitro.
SIGNIFICANCE: In summary, HDN attenuates lipid accumulation in vivo and in vitro via AMPK activation, suggesting that HDN may serve as a potential therapeutic agent for treating NAFLD.

Keywords:  Hesperidin; Lipid accumulation; Nonalcoholic fatty liver disease

DOI:  https://doi.org/10.1016/j.lfs.2022.120428
J Physiol Biochem. 2022 Mar 01.

Cordycepin alleviates myocardial ischemia/reperfusion injury by enhancing autophagy via AMPK-mTOR pathway.

Han Xu, Jing Cheng, Fei He.

  To estimate the cardioprotective mechanism of cordycepin on myocardial ischemia/reperfusion (I/R) injury. The left anterior descending artery of mice was ligated transiently to establish the myocardial I/R model. TTC/Evans Blue staining and TUNEL assay were performed to quantify the infarct size and apoptosis index. The cardiac function was evaluated by echocardiography. Neonatal rat ventricular cardiomyocytes (NRVCs) underwent hypoxia and reoxygenation (H/R). MTS and LDH were detected to measured cell viability and necrosis respectively. The results suggested that cordycepin could markedly decrease apoptosis, reduce infarct size, and improve cardiac function in mice subjected to I/R injury, alongside with enhanced autophagy. In NRVCs, cordycepin treatment obviously reduced ROS production. In addition, cordycepin partly promoted autophagy in the context of H/R injury by regulating AMPK/mTOR pathway. Our data demonstrated that cordycepin exerts cardio-protective effect and promotes cardiac functional recovery following myocardial I/R by enhancing autophagy via AMPK-mTOR signaling pathway.

Keywords:  AMPK/mTOR; Autophagy; Cordycepin; Ischemia reperfusion injury

DOI:  https://doi.org/10.1007/s13105-021-00816-x
Cancer Cell Int. 2022 Mar 04. 22(1): 102

CARM1 promotes gastric cancer progression by regulating TFE3 mediated autophagy enhancement through the cytoplasmic AMPK-mTOR and nuclear AMPK-CARM1-TFE3 signaling pathways.

Suzhen Yang, Jing Zhang, Di Chen, Jiayi Cao, Ying Zheng, Yuying Han, Yirong Jin, Shuhui Wang, Ting Wang, Lin Ma, Tingting Luo, Yan Wang, Wen Qin, Lei Dong.

   BACKGROUND: The role of CARM1 in tumors is inconsistent. It acts as an oncogene in most cancers but it inhibits the progression of liver and pancreatic cancers. CARM1 has recently been reported to regulate autophagy, but this function is also context-dependent. However, the effect of CARM1 on gastric cancer (GC) has not been studied. We aimed to explore whether CARM1 was involved in the progression of GC by regulating autophagy.
METHODS: The clinical values of CARM1 and autophagy in GC were evaluated by immunohistochemistry and qRT-PCR. Transmission electron microscopy, immunofluorescence and western blotting were employed to identify autophagy. The role of CARM1 in GC was investigated by CCK-8, colony formation and flow cytometry assays in vitro and a xenograft model in vivo. Immunoprecipitation assays were performed to determine the interaction of CARM1 and TFE3.
RESULTS: CARM1 was upregulated in clinical GC tissues and cell lines, and higher CARM1 expression predicted worse prognosis. CARM1 enhanced GC cell proliferation, facilitated G1-S transition and inhibited ER stress-induced apoptosis by regulating autophagy. Importantly, treatment with a CARM1 inhibitor rescued the tumor-promoting effects of CARM1 both in vitro and in vivo. Furthermore, we demonstrated that CARM1 promoted TFE3 nuclear translocation to induce autophagy through the cytoplasmic AMPK-mTOR and nuclear AMPK-CARM1-TFE3 signaling pathways.
CONCLUSION: CARM1 promoted GC cell proliferation, accelerated G1-S transition and reduced ER stress-induced apoptosis by regulating autophagy. Mechanistically, CARM1 triggered autophagy by facilitating TFE3 nuclear translocation through the AMPK-mTOR and AMPK-CARM1-TFE3 signaling pathways.

Keywords:  AMPK; Autophagy; CARM1; Gastric cancer; TFE3

DOI:  https://doi.org/10.1186/s12935-022-02522-0
Exp Ther Med. 2022 Mar;23(3): 222

Metformin reduces chondrocyte pyroptosis in an osteoarthritis mouse model by inhibiting NLRP3 inflammasome activation.

Jiangbo Yan, Dong Ding, Gangning Feng, Yong Yang, Yong Zhou, Long Ma, Haohui Guo, Zhidong Lu, Qunhua Jin.

  Osteoarthritis (OA) is an age-related degenerative disease, and its incidence is increasing with the ageing of the population. Metformin, as the first-line medication for the treatment of diabetes, has received increasing attention for its role in OA. The purpose of the present study was to confirm the therapeutic effect of metformin in a mouse model of OA and to determine the mechanism underlying the resultant delay in OA progression. The right knees of 8-week-old C57BL/6 male mice were subjected to destabilization of the medial meniscus (DMM). Metformin (200 mg/kg) was then administered daily for 4 or 8 weeks. Safranin O-fast green staining, H&E staining and micro-CT were used to analyse the structure and morphological changes. Immunohistochemical staining was used to detect type II collagen (Col II), matrix metalloproteinase 13 (MMP-13), NOD-like receptor protein 3 (NLRP3), caspase-1, gasdermin D (GSDMD) and IL-1β protein expression. Reverse transcription-quantitative PCR was used to detect the mRNA expression of NLRP3, caspase-1, GSDMD and IL-1β. Histomorphological staining showed that metformin delayed the progression of OA in the DMM model. With respect to cartilage, metformin decreased the Osteoarthritis Research Society International score, increased the thickness of hyaline cartilage and decreased the thickness of calcified cartilage. Regarding the mechanism, in cartilage, metformin increased the expression of Col II and decreased the expression of MMP-13, NLRP3, caspase-1, GSDMD and IL-1β. In addition, in subchondral bone, metformin inhibited osteophyte formation, increased the bone volume fraction (%) and the bone mineral density (g/cm3), decreased the trabecular separation (mm) in early stage of osteoarthritis (4 weeks) but the opposite in an advanced stage of osteoarthritis (8 weeks). Overall, metformin inhibited the activation of NLRP3 inflammasome, decreased cartilage degradation, reversed subchondral bone remodelling and inhibited chondrocyte pyroptosis.

Keywords:  NOD-like receptor protein 3; chondrocytes; metformin; osteoarthritis; pyroptosis

DOI:  https://doi.org/10.3892/etm.2022.11146
Front Endocrinol (Lausanne). 2022 ;13 821849

Changes in Skeletal Muscle PAK1 Levels Regulate Tissue Crosstalk to Impact Whole Body Glucose Homeostasis.

Karla E Merz, Ragadeepthi Tunduguru, Miwon Ahn, Vishal A Salunkhe, Rajakrishnan Veluthakal, Jinhee Hwang, Supriyo Bhattacharya, Erika M McCown, Pablo A Garcia, Chunxue Zhou, Eunjin Oh, Stephanie M Yoder, Jeffrey S Elmendorf, Debbie C Thurmond.

  Skeletal muscle accounts for ~80% of insulin-stimulated glucose uptake. The Group I p21-activated kinase 1 (PAK1) is required for the non-canonical insulin-stimulated GLUT4 vesicle translocation in skeletal muscle cells. We found that the abundances of PAK1 protein and its downstream effector in muscle, ARPC1B, are significantly reduced in the skeletal muscle of humans with type 2 diabetes, compared to the non-diabetic controls, making skeletal muscle PAK1 a candidate regulator of glucose homeostasis. Although whole-body PAK1 knockout mice exhibit glucose intolerance and are insulin resistant, the contribution of skeletal muscle PAK1 in particular was unknown. As such, we developed inducible skeletal muscle-specific PAK1 knockout (skmPAK1-iKO) and overexpression (skmPAK1-iOE) mouse models to evaluate the role of PAK1 in skeletal muscle insulin sensitivity and glucose homeostasis. Using intraperitoneal glucose tolerance and insulin tolerance testing, we found that skeletal muscle PAK1 is required for maintaining whole body glucose homeostasis. Moreover, PAK1 enrichment in GLUT4-myc-L6 myoblasts preserves normal insulin-stimulated GLUT4 translocation under insulin resistance conditions. Unexpectedly, skmPAK1-iKO also showed aberrant plasma insulin levels following a glucose challenge. By applying conditioned media from PAK1-enriched myotubes or myoblasts to β-cells in culture, we established that a muscle-derived circulating factor(s) could enhance β-cell function. Taken together, these data suggest that PAK1 levels in the skeletal muscle can regulate not only skeletal muscle insulin sensitivity, but can also engage in tissue crosstalk with pancreatic β-cells, unveiling a new molecular mechanism by which PAK1 regulates whole-body glucose homeostasis.

Keywords:  PAK1; crosstalk; diabetes; insulin resistance; skeletal muscle

DOI:  https://doi.org/10.3389/fendo.2022.821849
Endocrine. 2022 Mar 02.

Metformin enhances LDL-cholesterol uptake by suppressing the expression of the pro-protein convertase subtilisin/kexin type 9 (PCSK9) in liver cells.

Amjad Ali, Hema Unnikannan, Jasmin Shafarin, Khuloud Bajbouj, Jalal Taneera, Jibran Sualeh Muhammad, Haydar Hasan, Albert Salehi, Samir Awadallah, Mawieh Hamad.

   PURPOSE: Metformin (MF) intake associates with reduced levels of circulating low-density lipoprotein-cholesterol (LDL-C). This has been attributed to the activation of AMPK, which differentially regulates the expression of multiple genes involved in cholesterol synthesis and trafficking. However, the exact mechanism underlying the LDL-C lowering effect of MF remains ambiguous.
METHODS: MF-treated Hep-G2 and HuH7 cells were evaluated for cell viability and the expression status of key lipid metabolism-related genes along with LDL-C uptake efficiency.
RESULTS: MF treatment resulted in decreased expression and secretion of PCSK9, increased expression of LDLR and enhanced LDL-C uptake in hepatocytes. It also resulted in increased expression of activated AMPK (p-AMPK) and decreased expression of SREBP2 and HNF-1α proteins. Transcriptomic analysis of MF-treated Hep-G2 cells confirmed these findings and showed that other key lipid metabolism-related genes including those that encode apolipoproteins (APOB, APOC2, APOC3 and APOE), MTTP and LIPC are downregulated. Lastly, MF treatment associated with reduced HMG-CoA reductase expression and activity.
CONCLUSIONS: These findings suggest that MF treatment reduces circulating LDL-C levels by suppressing PCSK9 expression and enhancing LDLR expression; hence the potential therapeutic utility of MF in hypercholesterolemia.

Keywords:  HNF-1α; LDL-cholesterol; LDLR; Metformin; PCSK9; SREBP2

DOI:  https://doi.org/10.1007/s12020-022-03022-x
Food Funct. 2022 Mar 02.

Co-delivery of EGCG and lycopene via a pickering double emulsion induced synergistic hypolipidemic effect.

Qun Wang, Ling Wang, Abdullah, Wenni Tian, Mingyue Song, Yong Cao, Jie Xiao.

The concept of "synergy" and its applications has rapidly increased in the food industry as a practical strategy to preserve and improve health-promoting effects of the functional ingredients. In this study, hydrophilic epigallocatechin-3-gallate (EGCG) and lipophilic lycopene (LYC) were loaded separately (EGCG loaded PDE (PE), and LYC loaded PDE (PL), and also co-delivered (PEL) within a pickering double emulsion (PDE) system to induce synergistic hypolipidemic effect. Their effects on the serum lipid profile, weight of tissue fats, liver lipid droplet accumulation, and liver steatosis in a high-fat diet rat model were investigated. Moreover, different pathways (HMG-CoR, LDL-R, PPARγ and AMPK) involved in triggering hypolipidemic effects were verified at both mRNA and protein levels. The study's findings showed that inclusion of EGCG improved while LYC negatively affected the physical stability of PDE. The contents of total cholesterol and triacylglyceroles in serum and liver as well as the weight of tissue fats were substantially reduced in all groups (PE/PL/PEL). The alteration in absorption site of EGCG and enhanced bioaccessibility of LYC when delivered by PDE strengthened the hypolipidemic properties of PE and PL, mainly through triggering the pathways of HMG-CoR, LDL-R and PPARγ. Furthermore, the synergistic hypolipidemic effect of PEL was achieved mainly through the activation of the AMPK pathway.

DOI: https://doi.org/10.1039/d2fo00169a
Food Nutr Res. 2021 ;65

D-allulose ameliorates adiposity through the AMPK-SIRT1-PGC-1α pathway in HFD-induced SD rats.

Geum-Hwa Lee, Cheng Peng, Hwa-Young Lee, Seon-Ah Park, The-Hiep Hoang, Jung Hyun Kim, Soonok Sa, Go-Eun Kim, Jung-Sook Han, Han-Jung Chae.

   Background: Adiposity is a major health-risk factor, and D-allulose has beneficial effects on adiposity-related metabolic disturbances. However, the modes of action underlying anti-hyperglycemic and hypolipidemic activity are partly understood.
Objective: This study investigated the in vivo and in vitro effects of D-allulose involved in adipogenesis and activation of the AMPK/SIRT1/PGC-1α pathway in high-fat diet (HFD)-fed rats.
Design: In this study, 8-week-old male SD (Sprague Dawley) rats were divided into five groups (n = 8/group), (1) Control (chow diet, 3.5%); (2) 60% HFD; (3) 60% HFD supplemented with allulose powder (AP) at 0.4 g/kg; (4) 60% HFD supplemented with allulose liquid (AL) at 0.4 g/kg; (5) 60% HFD supplemented with glucose (AL) at 0.4 g/kg. All the group received the product through oral gavage for 6 weeks. Control and HFD groups were gavaged with double-distilled water.
Results: Rats receiving AP and AL showed reduced body weight gain and fat accumulation in HFD-fed rats. Also, supplementation of AL/AP regulated the cytokine secretion and recovered biochemical parameters to alleviate metabolic dysfunction and hepatic injury. Additionally, AL/AP administration improved adipocyte differentiation via regulation of the PPARγ and C/EBPα signaling pathway and adipogenesis-related genes owing to the combined effect of the AMPK/SIRT1 pathway. Furthermore, AL/AP treatment mediated PGC-1α expression triggering mitochondrial genesis via activating the AMPK phosphorylation and SIRT1 deacetylation activity in adipose tissue.
Conclusion: The anti-adiposity activity of D-allulose is observed on a marked alleviation in adipogenesis and AMPK/SIRT1/PGC-1α deacetylation in the adipose tissue of HFD-fed rat.

Keywords:  AMPK; D-allulose; SIRT1; adipose tissue; adiposity

DOI:  https://doi.org/10.29219/fnr.v65.7803
Biochim Biophys Acta Mol Basis Dis. 2022 Feb 23. pii: S0925-4439(22)00034-5. [Epub ahead of print] 166371

Disruption of polycystin-1 cleavage leads to cardiac metabolic rewiring in mice.

Andressa G Amaral, Camille C C da Silva, Julian D C Serna, Kinulpe Honorato-Sampaio, Jéssica A Freitas, Amaro N Duarte-Neto, Antonio C Bloise, Laura Cassina, Marcos Y Yoshinaga, Adriano B Chaves-Filho, Feng Qian, Sayuri Miyamoto, Alessandra Boletta, Silvana Bordin, Alicia J Kowaltowski, Luiz F Onuchic.

  Cardiovascular manifestations account for marked morbi-mortality in autosomal dominant polycystic kidney disease (ADPKD). Pkd1- and Pkd2-deficient mice develop cardiac dysfunction, however the underlying mechanisms remain largely unclear. It is unknown whether impairment of polycystin-1 cleavage at the G-protein-coupled receptor proteolysis site, a significant ADPKD mutational mechanism, is involved in this process. We analyzed the impact of polycystin-1 cleavage on heart metabolism using Pkd1V/V mice, a model unable to cleave this protein and with early cardiac dysfunction. Pkd1V/V hearts showed lower levels of glucose and amino acids and higher lipid levels than wild-types, as well as downregulation of p-AMPK, p-ACCβ, CPT1B-Cpt1b, Ppara, Nppa and Acta1. These findings suggested decreased fatty acid β-oxidation, which was confirmed by lower oxygen consumption by Pkd1V/V isolated mitochondria using palmitoyl-CoA. Pkd1V/V hearts also presented increased oxygen consumption in response to glucose, suggesting that alternative substrates may be used to generate energy. Pkd1V/V hearts displayed a higher density of decreased-size mitochondria, a finding associated with lower MFN1, Parkin and BNIP3 expression. These derangements were correlated with increased apoptosis and inflammation but not hypertrophy. Notably, Pkd1V/V neonate cardiomyocytes also displayed shifts in oxygen consumption and p-AMPK downregulation, suggesting that, at least partially, the metabolic alterations are not induced by kidney dysfunction. Our findings reveal that disruption of polycystin-1 cleavage leads to cardiac metabolic rewiring in mice, expanding the understanding of heart dysfunction associated with Pkd1 deficiency and likely with human ADPKD.

Keywords:  Autosomal dominant polycystic kidney disease; Cardiac dysfunction; Lipid derangement; Metabolic rewiring; Mitochondria; Polycystin-1 cleavage at GPS

DOI:  https://doi.org/10.1016/j.bbadis.2022.166371
Front Immunol. 2022 ;13 820524

P2Y1R Ligation Suppresses Th17 Cell Differentiation and Alleviates Colonic Inflammation in an AMPK-Dependent Manner.

Yao-Yao Chang, Qiu-Chan Huan, Jiao Peng, Wen-Chun Bi, Li-Xiang Zhai, Yan Chen, Jonathan R Lamb, Xiang-Chun Shen, Zhao-Xiang Bian, Hai-Qiang Wu, Yong-Xian Cheng, Hai-Tao Xiao.

  P2Y1 receptor is a G-protein-coupled receptor that plays a critical role in the immune response of inflammatory bowel diseases. However, its regulatory effects on CD4+ T cell response have not been fully elucidated. The study aimed to characterize the role of P2Y1R in Th17 cell differentiation and colonic inflammation. Our results demonstrated that P2Y1R was significantly increased in the splenocytes of colitic mice, which was positively associated with the expression of RORγt and IL-17A. P2Y1R deficiency significantly ameliorated DSS-induced colitis and its Th17 responses. In parallel, P2Y1R deficiency greatly impaired the differentiation of Th17 cell, down-regulated the mRNA expression of IL-17A and RORγt, and protein expression of RORγt in vitro. More importantly, it was found that P2Y1R deficiency markedly increased AMPK phosphorylation of Th17 polarized CD4+ T cells, and antagonist of AMPK significantly reversed the inhibitory effect of P2Y1R deficiency on Th17 cell generation in vivo and in vitro. Overall, these findings demonstrated that P2Y1R deficiency could suppress Th17 cell differentiation in an AMPK-dependent manner to ameliorate colitis, and P2Y1R can act as an important regulator of Th17 cell differentiation to control colonic inflammation.

Keywords:  AMPK; P2Y1R; Th17 cell; colitis; differentiation

DOI:  https://doi.org/10.3389/fimmu.2022.820524
Behav Neurol. 2022 ;2022 6711160

Metformin Alleviates Autistic-Like Behaviors Elicited by High-Fat Diet Consumption and Modulates the Crosstalk Between Serotonin and Gut Microbiota in Mice.

Wenlin Deng, Haoran Ke, Siqi Wang, Zitong Li, Sitao Li, Pinjing Lv, Fang Li, Ye Chen.

The biological mechanisms linking diet-related obesity and autistic behaviors remain unclear. Metformin has proven to be beneficial in the treatment of many syndromes, including autism spectrum disorder. Therefore, the aim of this study was to assess whether metformin treatment could ameliorate metabolic and behavioral alterations in C57BL/6 mice kept on a high-fat diet (HFD), and whether these changes were related to modifications in the gut microbiota and 5-HT levels. As expected, ten weeks of HFD ingestion increased body weight, adiposity, and glucose levels. HFD-fed mice showed a marked aggravation of repetitive behaviors (marble burying and self-grooming), and this was prevented by metformin administration. In addition, HFD-fed mice increased the total distance travelled in the open field test. This hyperactivity was counteracted by metformin cotreatment. In the elevated plus maze test, HFD-fed mice showed a reduced number of entries into the open arms. Interestingly, both HFD and metformin cotreatment increased social interactions in the three-chamber test. HFD increased the levels of intestinal tryptophan and 5-hydroxyindoleacetic acid. Metformin stimulated gut tryptophan and promoted the synthesis of 5-HT in the HFD group. Lactococcus, Trichococcus, Romboutsia, and Faecalibaculum were enriched in HFD-fed mice, whereas the HFD group cotreated with metformin was enriched in Intestinimonas and L. reuteri. Faecalibacterium was positively correlated with sociability and 5-HT pathway components in mice that received metformin. In summary, HFD consumption elicited a complex phenotype comprising higher levels of anxiety-like and repetitive behaviors but also increased sociability. Metformin could potentially improve HFD-induced disorders in the autistic spectrum through a mechanism involving positive modulation of 5-HT levels in the gut and its microbiota composition.

DOI: https://doi.org/10.1155/2022/6711160
J Clin Invest. 2022 Mar 01. pii: e131053. [Epub ahead of print]

HRAS germline mutations impair LKB1/AMPK signaling and mitochondrial homeostasis in Costello syndrome models.

Laetitia Dard, Christophe Hubert, Pauline Esteves, Wendy Blanchard, Ghina Bou About, Lyla Baldasseroni, Elodie Dumon, Chloe Angelini, Mégane Delourme, Véronique Guyonnet-Duperat, Stephane Claverol, Marc Bonneu, Laura Fontenille, Karima Kissa, Pierre-Emmanuel Séguéla, Jean-Benoît Thambo, Nicolas Levy, Yann Herault, Nadège Bellance, Nivea Dias Amoedo, Frederique Magdinier, Tania Sorg, Didier Lacombe, Rodrigue Rossignol.

  Germline mutations that activate genes in the canonical RAS/MAPK signaling pathway are responsible for rare human developmental disorders known as RASopathies. Here, we analyzed the molecular determinants of Costello syndrome (CS) using a mouse model expressing HRAS p.G12S, patient skin fibroblasts, hiPSC-derived human cardiomyocytes, a HRAS p.G12V zebrafish model and human fibroblasts expressing lentiviral constructs carrying HRAS p.G12S or HRAS p.G12A mutations. The findings revealed alteration of mitochondrial proteostasis and defective oxidative phosphorylation in the heart and skeletal muscle of Costello mice that were also found in the cell models of the disease. The underpinning mechanisms involved the inhibition of the AMPK signaling pathway by mutant forms of HRAS, leading to alteration of mitochondrial proteostasis and bioenergetics. Pharmacological activation of mitochondrial bioenergetics and quality control restored organelle function in HRAS p.G12A and p.G12S cell models, reduced left ventricle hypertrophy in the CS mice and diminished the occurrence of developmental defects in the CS zebrafish model. Collectively, these findings highlight the importance of mitochondrial proteostasis in the pathophysiology of RASopathies and suggest that patients with Costello syndrome may benefit from treatment with mitochondrial modulators.

Keywords:  Bioenergetics; Metabolism

DOI:  https://doi.org/10.1172/JCI131053
Poult Sci. 2022 Jan 21. pii: S0032-5791(22)00047-5. [Epub ahead of print]101(4): 101742

Dietary fibers with different viscosity regulate lipid metabolism via ampk pathway: roles of gut microbiota and short-chain fatty acid.

Yu Li, Daiyang Xia, Jianying Chen, Xiufen Zhang, Heng Wang, Liang Huang, Jiajia Shen, Shunxiang Wang, Yan Feng, Danyan He, Jiaqing Wang, Hui Ye, Yongwen Zhu, Lin Yang, Wence Wang.

  Dietary fiber (DF) improves gastrointestinal health and has important associations with the alleviation of intestinal diseases and metabolic syndrome. However, due to DFs complex characteristics, such as solubility, viscosity, and fermentability, the mechanism in these was not consistent. As an herbivore, the goose has a prominent digestive ability to DF. Therefore, we choose low, medium, and high viscosity DFs (respectively resistant starch-3 []RS], inulin [INU], and β-glucan [GLU]) as Magang goose diet treatment for 4 wk, to investigate the effect and potential mechanism of different viscosities DFs on the growth and development process of goose. In summary, three degrees of viscous DFs could decrease the mechanismic lipid level of geese by promoting acid-producing bacteria and short-chain fatty acid (SCFA) production, therefore, activating AMPK pathway-related genes through the gut-liver axis. High viscous DF has a greater lipid-lowering effect on geese, while medium viscous DF has preferable intestinal mucosal protection.

Keywords:  AMPK; SCFAs; dietary fiber; gut microbiota; lipid metabolism

DOI:  https://doi.org/10.1016/j.psj.2022.101742
Blood. 2022 Mar 03. 139(9): 1267-1269

PP2A activation targets AML stem cells.

Nicole M Verrills.

DOI: https://doi.org/10.1182/blood.2021014677
Diabetologia. 2022 Mar 04.

Maturation of beta cells: lessons from in vivo and in vitro models.

Tom Barsby, Timo Otonkoski.

  The ability to maintain normoglycaemia, through glucose-sensitive insulin release, is a key aspect of postnatal beta cell function. However, terminally differentiated beta cell identity does not necessarily imply functional maturity. Beta cell maturation is therefore a continuation of beta cell development, albeit a process that occurs postnatally in mammals. Although many important features have been identified in the study of beta cell maturation, as of yet no unified mechanistic model of beta cell functional maturity exists. Here, we review recent findings about the underlying mechanisms of beta cell functional maturation. These findings include systemic hormonal and nutritional triggers that operate through energy-sensing machinery shifts within beta cells, resulting in primed metabolic states that allow for appropriate glucose trafficking and, ultimately, insulin release. We also draw attention to the expansive synergistic nature of these pathways and emphasise that beta cell maturation is dependent on overlapping regulatory and metabolic networks.

Keywords:  AMPK; Beta cells; Circadian; Differentiation; Islets; Maturation; Metabolism; Review; Stem cells; mTOR

DOI:  https://doi.org/10.1007/s00125-022-05672-y
Biochem Biophys Res Commun. 2022 Feb 21. pii: S0006-291X(22)00248-0. [Epub ahead of print]601 45-51

Exercise activates autophagy and regulates endoplasmic reticulum stress in muscle of high-fat diet mice to alleviate insulin resistance.

Fangzhou Cheng, Yaoshan Dun, Jing Cheng, Jeffrey W Ripley-Gonzalez, Wenlong Jiang, Baiyang You, Suixin Liu.

  Exercise training has been demonstrated as an effective therapy for insulin resistance (IR) to relieve skeletal muscle metabolic disorders. Physiologic protective autophagy was found blocked by IR induced severe endoplasmic reticulum (ER) stress, which may lead to progression of IR. However, the mechanisms are not fully understood. Therefore, this study sought to investigate that how exercise training act on IR through an exploration into the mechanism of ER stress and high-fat diet (HFD)-blocked autophagy. A rodent model was adopted in mice via a HFD and an 8-week swim exercise training intervention. The mouse IR model was successfully established through HFD treatment: body mass, adipose weight, HOMA-IR index increased, as well as IRS1, inhibited in the muscle of HFD mice. Moreover, the AMPK/PGC1α pathway was depressed and IRE1, PERK, ATF6-related ER stress signaling was activated in the muscle of HFD mice. While autophagy factors, including BNIP3, LC3II/LC3I, and PINK1, decreased. However, additional 8-week exercise training during HFD was found to reverse all these changes and alleviate IR. Thus, exercise training could facilitate HFD-blocked protective autophagy via the activation of the AMPK/PGC1α pathway to relieve insulin resistance in mice. Our study provides experimental data for the prevention of T2DM and insulin resistance.

Keywords:  AMPK; Autophagy; Endoplasmic reticulum stress; Exercise; Insulin resistance

DOI:  https://doi.org/10.1016/j.bbrc.2022.02.058
Eur J Pharmacol. 2022 Feb 24. pii: S0014-2999(22)00119-4. [Epub ahead of print]920 174858

Acacetin ameliorates cardiac hypertrophy by activating Sirt1/AMPK/PGC-1α pathway.

Yu-Kai Cui, Yi-Xiang Hong, Wei-Yin Wu, Wei-Min Han, Yao Wu, Chan Wu, Gui-Rong Li, Yan Wang.

  Cardiac hypertrophy is a major risk factor for developing heart failure. This study investigates the effects of the natural flavone acacetin on myocardial hypertrophy in cellular level and whole animals. In cardiomyocytes from neonatal rat with hypertrophy induced by angiotensin II (Ang II), acacetin at 0.3, 1, and 3 μM reduced the increased myocyte surface area, brain natriuretic peptide (BNP), and ROS production by upregulating anti-oxidative molecules (i.e. Nrf2, SOD1, SOD2, HO-1), anti-apoptotic protein Bcl-2, and downregulating the pro-apoptotic protein Bax and the inflammatory cytokine IL-6 in a concentration-dependent manner. In addition, acacetin rescued Ang II-induced impairment of PGC-1α, PPARα and pAMPK. These beneficial effects of acacetin were mediated by activation of Sirt1, which was confirmed in cardiac hypertrophy induced by abdominal aorta constriction (AAC) in SD rats. Acacetin prodrug (10 mg/kg, s.c., b.i.d.) treatment reduced the elevated artery blood pressure, improved the increased heart size and thickness of left ventricular wall and the ventricular fibrosis associated with inhibiting myocardial fibrosis and BNP, and reversed the impaired protective signal molecules including PGC-1α, Nrf2, PPARα, pAMPK and Sirt1 of left ventricular tissue. Our results demonstrate the novel pharmacological effect that acacetin ameliorates cardiac hypertrophy via Sirt1-mediated activation of AMPK/PGC-1α signal molecules followed by reducing oxidation, inflammation and apoptosis.

Keywords:  AMPK; Angiotensin Ⅱ; Cardiac hypertrophy; PGC-1α; Sirt1

DOI:  https://doi.org/10.1016/j.ejphar.2022.174858
J Biol Chem. 2022 Feb 23. pii: S0021-9258(22)00208-3. [Epub ahead of print] 101768

Moderate L-lactate administration suppresses adipose tissue macrophage M1 polarization to alleviate obesity-associated insulin resistance.

Hao Cai, Xin Wang, Zhixin Zhang, Juan Chen, Fangbin Wang, Lu Wang, Jian Liu.

  As a crucial metabolic intermediate, L-lactate is involved in redox balance, energy balance, and acid-base balance in organisms. Moderate exercise training transiently elevates plasma L-lactate levels and ameliorates obesity-associated type 2 diabetes. However, whether moderate L-lactate administration improves obesity-associated insulin resistance remains unclear. In this study, we defined 800 mg/kg/day as the dose of moderate L-lactate administration. In mice fed with a high-fat diet (HFD), moderate L-lactate administration for 12 weeks was shown to alleviate weight gain, fat accumulation, and insulin resistance. Along with the phenotype alterations, white adipose tissue thermogenesis was also found to be elevated in HFD-fed mice. Meanwhile, moderate L-lactate administration suppressed the infiltration and pro-inflammatory M1 polarization of adipose tissue macrophages (ATMs) in HFD-fed mice. Furthermore, L-lactate treatment suppressed the lipopolysaccharide (LPS)-induced M1 polarization of bone marrow-derived macrophages (BMDMs). L-lactate can bind to the surface receptor GPR132, which typically drives the downstream cAMP-PKA signaling. As a nutrient sensor, AMPK critically controls macrophage inflammatory signaling and phenotype. Thus, utilizing inhibitors of the kinases PKA and AMPK as well as siRNA against GPR132, we demonstrated that GPR132-PKA-AMPKα1 signaling mediated the suppression caused by L-lactate treatment on BMDM M1 polarization. Finally, L-lactate addition remarkably resisted the impairment of LPS-treated BMDM conditional media on adipocyte insulin sensitivity. In summary, moderate L-lactate administration suppresses ATM pro-inflammatory M1 polarization through activation of the GPR132-PKA-AMPKα1 signaling pathway to improve insulin resistance in HFD-fed mice, suggesting a new therapeutic and interventional approach to obesity-associated type 2 diabetes.

Keywords:  Adipose tissue macrophage; GPR132-PKA-AMPKα1 pathway; Insulin resistance; Moderate L-lactate administration; Obesity

DOI:  https://doi.org/10.1016/j.jbc.2022.101768
J Ethnopharmacol. 2022 Feb 28. pii: S0378-8741(22)00191-X. [Epub ahead of print] 115153

NF-κB and AMPK-Nrf2 pathways support the protective effect of polysaccharides from Polygonatum cyrtonema Hua in lipopolysaccharide-induced acute lung injury.

Qingxia Gan, Xi Wang, Mayijie Cao, Song Zheng, Yuntong Ma, Qinwan Huang.

   ETHNOPHARMACOLOGICAL RELEVANCE: The raw and honey-processed P. cyrtonema recorded in ancient classics of Chinese medicine as having the effect of moisturizing the lungs and relieving coughs, and it has also been proved to have therapeutic effects on lung diseases in modern research. Polysaccharides are the main components with biological activities in raw and honey-processed P. cyrtonema, but there is no research for their lung-protective effect.
AIM OF STUDY: This study aimed to investigate the protective effect and the possible mechanism of polysaccharides from raw and honey-processed P. cyrtonema in LPS-induced acute lung injury in mice.
MATERIALS AND METHODS: Polysaccharides, PCP and HPCP, were respectively separated and extracted from raw and honey-processed P. cyrtonema, and the molecular weight, monosaccharide composition and other basic chemical characteristics were analysed by HPGCP, HPLC, FI-IR, and NMR. The model of ALI mice was established by intratracheal instillation of LPS. Moreover, the protective effects of PCP and HPCP for ALI mice were evaluated by detecting the wet-to-dry ratio and histopathology in the lungs, the content of inflammatory factors TNF-α, IL-6, IL-1β in BLAF, and the content of MPO and SOD in lung tissue. In addition, the lung-protective mechanism of PCP and HPCP was explored by detecting the levels of some proteins and mRNA related to inflammation and oxidative stress pathways.
RESULTS: PCP and HPCP with molecular weights of 8.842×103 and 5.521×103Da were mainly composed of three monosaccharides. Moreover, it is found that fructose and galactose were mainly β-D, and glucose was α-D. Both PCP and HPCP could significantly improve lung injury, reduce the level of inflammatory factors in BALF and the level of MPO in lung tissue, and increase the level of SOD. In addition, PCR and WB indicated that PCP and HPCP at least inhibited pulmonary inflammation through the NF-κB pathway, and reduced the occurrence of pulmonary oxidative stress through the AMPK-Nrf2 pathway.
CONCLUSIONS: Polysaccharides from raw and honey-processed P. cyrtonema had a protective effect in LPS-induced lung injury in mice. This effect may be related to the antioxidant and anti-inflammatory activities of PCP and HPCP in the lungs through the NF-κB pathway and AMPK-Nrf2 pathway. And HPCP seems to perform more than PCP.

Keywords:  AMPK-Nrf2 pathway; Acute lung injury; NF-κB pathway; Polygonatum cyrtonema Hua; Polysaccharides

DOI:  https://doi.org/10.1016/j.jep.2022.115153