bims-amsmem 2022-05-08 papers

bims-amsmem

Biomed News

on AMPK signaling mechanism in energy metabolism

Issue of 2022‒05‒08
29 papers selected by
Dipsikha Biswas, Københavns Universitet

AICAR promotes endothelium-independent vasorelaxation by activating AMP-activated protein kinase via increased ZMP and decreased ATP/ADP ratio in aortic smooth muscle.
Caspase cleavage and nuclear retention of the energy sensor AMPK-α1 during apoptosis.
RGS6 Drives Spinal Cord Injury by Inhibiting AMPK Pathway in Mice.
Calycosin-7-O-β-D-glucoside attenuates palmitate-induced lipid accumulation in hepatocytes through AMPK activation.
Identification of novel indole derivatives as highly potent AMPK activators with anti-diabetic profiles.
USP2 in the ventromedial hypothalamus modifies blood glucose levels by controlling sympathetic nervous activation.
Dammarane-type triterpenoids from Gynostemma compressum X. X. Chen & D. R. Liang (Cucurbitaceae) and their AMPK activation effect in 3T3-L1 cells.
Substrate recognition by Arg/Pro-rich insert domain in calcium/calmodulin-dependent protein kinase kinase for target protein kinases.
AMP activated kinase negatively regulates hepatic Fetuin-A via p38 MAPK-C/EBPβ/E3 Ubiquitin Ligase Signaling pathway.
LKB1 suppression promotes cardiomyocyte regeneration via LKB1-AMPK-YAP axis.
Maternal High-Fat Diet Impairs Placental Fatty Acid β-Oxidation and Metabolic Homeostasis in the Offspring.
Metabolic regulation of (-)-epicatechin and the colonic metabolite 2,3-dihydroxybenzoic acid on the glucose uptake, lipid accumulation and insulin signalling in cardiac H9c2 cells.
Metformin suppresses epithelial sodium channel hyperactivation and its associated phenotypes in a mouse model of obstructive lung diseases.
Cardioprotective effect of ginsenoside Rb1 via regulating metabolomics profiling and AMP-activated protein kinase-dependent mitophagy.
IM156, a new AMPK activator, protects against polymicrobial sepsis.
The sex-specific role of sensory neuron LKB1 on metabolic stress-induced mechanical hypersensitivity and mitochondrial respiration.
Ginsenoside Rg3 ameliorates myocardial glucose metabolism and insulin resistance via activating the AMPK signaling pathway.
Plasmalogen Inhibits Body Weight Gain by Activating Brown Adipose Tissue and Improving White Adipose Tissue Metabolism.
Ferulic acid ameliorates acetaminophen-induced acute liver injury by promoting AMPK-mediated protective autophagy.
Porcine parvovirus triggers autophagy through the AMPK/Raptor/mTOR pathway to promote viral replication in porcine placental trophoblasts.
Kaempferol Mediated AMPK/mTOR Signal Pathway Has a Protective Effect on Cerebral Ischemic-Reperfusion Injury in Rats by Inducing Autophagy.
Selenium-Enriched Probiotic Alleviates Western Diet-Induced Non-alcoholic Fatty Liver Disease in Rats via Modulation of Autophagy Through AMPK/SIRT-1 Pathway.
The AMPK-related kinase NUAK2 suppresses glutathione peroxidase 4 expression and promotes ferroptotic cell death in breast cancer cells.
Electrical stimulated GLUT4 signalling attenuates critical illness-associated muscle wasting.
Mogrol suppresses lung cancer cell growth by activating AMPK-dependent autophagic death and inducing p53-dependent cell cycle arrest and apoptosis.
Irisin protects cardiomyocytes against hypoxia/reoxygenation injury via attenuating AMPK mediated endoplasmic reticulum stress.
Regulation of apoptosis and autophagy by albendazole in human colon adenocarcinoma cells.
Identifying novel SMYD3 interactors on the trail of cancer hallmarks.
A comprehensive review on the glucoregulatory properties of food-derived bioactive peptides.

J Basic Clin Physiol Pharmacol. 2022 May 04.

AICAR promotes endothelium-independent vasorelaxation by activating AMP-activated protein kinase via increased ZMP and decreased ATP/ADP ratio in aortic smooth muscle.

Rajkumar Pyla, Thomas J Hartney, Lakshman Segar.

  OBJECTIVES: AICAR, an adenosine analog, has been shown to exhibit vascular protective effects through activation of AMP-activated protein kinase (AMPK). However, it remains unclear as to whether adenosine kinase-mediated ZMP formation or adenosine receptor activation contributes to AICAR-mediated AMPK activation and/or vasorelaxant response in vascular smooth muscle.METHODS AND RESULTS: In the present study using endothelium-denuded rat aortic ring preparations, isometric tension measurements revealed that exposure to 1 mM AICAR for 30 min resulted in inhibition of phenylephrine (1 μM)-induced smooth muscle contractility by ∼35%. Importantly, this vasorelaxant response by AICAR was prevented after pretreatment of aortic rings with an AMPK inhibitor (compound C, 40 µM) and adenosine kinase inhibitor (5-iodotubercidin, 1 µM), but not with an adenosine receptor blocker (8-sulfophenyltheophylline, 100 µM). Immunoblot analysis of respective aortic tissues showed that AMPK activation seen during vasorelaxant response by AICAR was abolished by compound C and 5-iodotubercidin, but not by 8-sulfophenyltheophylline, suggesting ZMP involvement in AMPK activation. Furthermore, LC-MS/MS MRM analysis revealed that exposure of aortic smooth muscle cells to 1 mM AICAR for 30 min enhanced ZMP level to 2014.9 ± 179.4 picomoles/mg protein (vs. control value of 8.5 ± 0.6; p<0.01), which was accompanied by a significant decrease in ATP/ADP ratio (1.08 ± 0.02 vs. 2.08 ± 0.06; p<0.01).
CONCLUSIONS: Together, the present findings demonstrate that AICAR-mediated ZMP elevation and the resultant AMPK activation in vascular smooth muscle contribute to vasorelaxation.

Keywords:  AICAR; AMPK; ZMP; vascular smooth muscle; vasorelaxation

DOI:  https://doi.org/10.1515/jbcpp-2021-0308
Cell Rep. 2022 05 03. pii: S2211-1247(22)00525-3. [Epub ahead of print]39(5): 110761

Caspase cleavage and nuclear retention of the energy sensor AMPK-α1 during apoptosis.

Anees Rahman Cheratta, Faisal Thayyullathil, Simon A Hawley, Fiona A Ross, Abdelmajdid Atrih, Douglas J Lamont, Siraj Pallichankandy, Karthikeyan Subburayan, Ameer Alakkal, Rachid Rezgui, Alex Gray, D Grahame Hardie, Sehamuddin Galadari.

  AMP-activated protein kinase (AMPK) coordinates energy homeostasis during metabolic and energy stress. We report that the catalytic subunit isoform AMPK-α1 (but not α2) is cleaved by caspase-3 at an early stage during induction of apoptosis. AMPK-α1 cleavage occurs following Asp529, generating an ∼58-kDa N-terminal fragment (cl-AMPK-α1) and leading to the precise excision of the nuclear export sequence (NES) from the C-terminal end. This cleavage does not affect (1) the stability of pre-formed heterotrimeric complexes, (2) the ability of cl-AMPK-α1 to become phosphorylated and activated by the upstream kinases LKB1 or CaMKK2, or (3) allosteric activation by AMP or A-769662. Importantly, cl-AMPK-α1 is only detectable in the nucleus, consistent with removal of the NES, and ectopic expression of cleavage-resistant D529A-mutant AMPK-α1 promotes cell death induced by cytotoxic agents. Thus, we have elucidated a non-canonical mechanism of AMPK activation within the nucleus, which protects cells against death induced by DNA damage.

Keywords:  AMPK; CP: Cell biology; CP: Molecular biology; anti-Fas; apoptosis; caspase; catalytic; cl-AMPK-α1; cleavage; etoposide; kinase; nuclear export sequence

DOI:  https://doi.org/10.1016/j.celrep.2022.110761
Dis Markers. 2022 ;2022 4535652

RGS6 Drives Spinal Cord Injury by Inhibiting AMPK Pathway in Mice.

Wenxin Dao, Zhe Xiao, Weize Yang, Xiaomin Luo, Hongxia Xia, Zuneng Lu.

Objective: Oxidative stress and inflammation play critical roles in the pathogenesis of spinal cord injury (SCI). Regulator of G protein signaling 6 (RGS6) is involved in controlling ROS generation and inflammatory response under different contexts. This study is aimed at investigating its role and underlying mechanism in SCI.Methods: Contusive SCI mouse models were generated, and lentiviral vectors were injected to silence or overexpress RGS6 in the spinal cord. To inhibit AMP-activated protein kinase (AMPK) activity, SCI mice were intraperitoneally injected with compound C (20 mg/kg) every two days. Oxidative and inflammatory markers were detected.
Results: Spinal RGS6 expression was elevated upon SCI stimulation. RGS6 knockdown suppressed, while RGS6 overexpression aggravated oxidative stress, inflammation, and SCI in mice. Mechanistically, RGS6 elevation during SCI deactivated AMPK pathway, thereby exacerbating oxidative stress and inflammation in SCI mice.
Conclusion: RGS6 is required for the initiation and progression of SCI, and knocking down RGS6 may provide promising therapeutic strategies for SCI patients.

DOI: https://doi.org/10.1155/2022/4535652
Eur J Pharmacol. 2022 Apr 28. pii: S0014-2999(22)00249-7. [Epub ahead of print] 174988

Calycosin-7-O-β-D-glucoside attenuates palmitate-induced lipid accumulation in hepatocytes through AMPK activation.

Wan Xu, Feiye Zhou, Qin Zhu, Mengyao Bai, Tiancheng Luo, Libin Zhou, Ruyuan Deng.

  Calycosin-7-O-β-D-glucoside (CG) is the major component of Astragali Radix (AR), a traditional Chinese drug. As reported, CG could attenuate cerebral ischemia/reperfusion injury, protect blood-brain barrier integrity, and ameliorate myocardial infarction. To date, whether CG has a protective effect on metabolic diseases remains to be elucidated. In the present study, CG could attenuate palmitate-induced lipid accumulation in hepatocytes in a dose-dependent manner, with down-regulation of lipogenesis related genes expression and up-regulation of lipids β-oxidation related genes expression. CG could decrease the triglyceride (TG) content from 0.30 mmol/g protein to 0.21 mmol/g protein and reduce the total cholesterol (TC) content from 0.39 mmol/g protein to 0.26 mmol/g protein. Moreover, CG stimulated the phosphorylation of AMP-activated protein kinase (AMPK), and the protective effect of CG on hepatocytes was partially reversed both by the inhibitor of AMPK signaling pathway and overexpression of AMPK-DN. Our findings revealed that CG could ameliorate palmitate-induced lipids accumulation in hepatocytes via AMPK activation and it may be a promising therapeutic medicine for hepatic steatosis.

Keywords:  AMPK; Calycosin-7-O-β-D-glucoside; Hepatic steatosis; Hepatocyte; Lipogenesis

DOI:  https://doi.org/10.1016/j.ejphar.2022.174988
Bioorg Med Chem Lett. 2022 May 02. pii: S0960-894X(22)00245-1. [Epub ahead of print] 128769

Identification of novel indole derivatives as highly potent AMPK activators with anti-diabetic profiles.

Yuusuke Tamura, Ippei Morita, Yu Hinata, Eiichi Kojima, Hiroki Ozasa, Hidaka Ikemoto, Mutsumi Asano, Toshihiro Wada, Yoko Hayasaki-Kajiwara, Takanori Iwasaki, Kenichi Matsumura.

  AMP-activated protein kinase (AMPK) has been shown to play an important role in the beneficial effects of exercise on glucose and lipid metabolism in skeletal muscle and liver. Therefore, activation of AMPK has been proposed as an attractive strategy for the treatment of metabolic disorders, such as type 2 diabetes. Many of existing AMPK activators bearing diverse chemical structure were reported. However, there have been few reports of direct AMPK activator with high potency for β2-AMPK isoform, which is thought to be important for glucose homeostasis, and their chemical structure is limited to benzimidazole core. We describe herein our efforts for identification of novel AMPK activator. Our newly designed 4-azaindole derivative 16g exhibited single-digit nM in vitro activity, and chronic treatment with 16g led to dose-dependent improvement in HbA1c as well as decrease in hepatic lipid accumulation in diabetic animal model.

Keywords:  AMPK activator; Indole; Type 2 diabetes

DOI:  https://doi.org/10.1016/j.bmcl.2022.128769
J Neurosci. 2022 Apr 26. pii: JN-RM-2504-21. [Epub ahead of print]

USP2 in the ventromedial hypothalamus modifies blood glucose levels by controlling sympathetic nervous activation.

Mayuko Hashimoto, Masaki Fujimoto, Kohtarou Konno, Ming Liang Lee, Yui Yamada, Koya Yamashita, Chitoku Toda, Michio Tomura, Masahiko Watanabe, Osamu Inanami, Hiroshi Kitamura.

Ubiquitin-specific protease (USP) 2 participates in glucose metabolism in peripheral tissues such as the liver and skeletal muscle. However, the glucoregulatory role of USP2 in the central nervous system is not well known. In this study, we focus on USP2 in the ventromedial hypothalamus (VMH), which has dominant control over systemic glucose homeostasis. ISH using a Usp2-specific probe showed that Usp2 mRNA is present in VMH neurons, as well as other glucoregulatory nuclei, in the hypothalamus of male mice. Administration of a USP2-selective inhibitor, ML364 (20 ng/head), into the VMH elicited a rapid increase in the circulating glucose level in male mice, suggesting USP2 has a suppressive role on glucose mobilization. ML364 treatment also increased serum norepinephrine concentration, while it negligibly affected serum levels of insulin and corticosterone. ML364 perturbated mitochondrial oxidative phosphorylation in neural SH-SY5Y cells, and subsequently promoted the phosphorylation of AMP-activated protein kinase (AMPK). Consistent with these findings, hypothalamic ML364 treatment stimulated AMPKα phosphorylation in the VMH. Inhibition of hypothalamic AMPK prevented ML364 from increasing serum norepinephrine and blood glucose. Removal of ROS restored the ML364-evoked mitochondrial dysfunction in SH-SY5Y cells and impeded the ML364-induced hypothalamic AMPKα phosphorylation, as well as prevented the elevation of serum norepinephrine and blood glucose levels in male mice. These results indicate hypothalamic USP2 attenuates perturbations in blood glucose levels by modifying the ROS-AMPK-sympathetic nerve axis.Significance statement:Under normal conditions (excluding hyperglycemia or hypoglycemia), blood glucose levels are maintained at a constant level. In this study, we used a mouse model to identify a hypothalamic protease controlling blood glucose levels. Pharmacological inhibition of ubiquitin-specific protease (USP) 2 in the ventromedial hypothalamus (VMH) caused a deviation in blood glucose levels under a non-stressed condition, indicating that USP2 determines the set point of the blood glucose level. Modification of sympathetic nervous activity accounts for the USP2-mediated glucoregulation. Mechanistically, USP2 mitigates the accumulation of ROS in the VMH, resulting in attenuation of the phosphorylation of AMP-activated protein kinase (AMPK). Based on these findings, we uncovered a novel glucoregulatory axis consisting of hypothalamic USP2, ROS, AMPK, and the sympathetic nervous system.

DOI: https://doi.org/10.1523/JNEUROSCI.2504-21.2022
Phytochemistry. 2022 Apr 28. pii: S0031-9422(22)00134-0. [Epub ahead of print]200 113218

Dammarane-type triterpenoids from Gynostemma compressum X. X. Chen & D. R. Liang (Cucurbitaceae) and their AMPK activation effect in 3T3-L1 cells.

Thi Thanh Thuy Dinh, Thi Thu Nguyen, Huy Trung Ngo, Thi Hien Tran, Ba Vinh Le, Thanh Huyen Pham, Ha Thanh Tung Pham, Thanh Ky Pham, Thi Ha Do.

  Bioassay-guided fractionation of the 80% ethanol extract of Gynostemma compressum X. X. Chen & D. R. Liang (Cucurbitaceae) resulted in the isolation and identification of eight undescribed triterpenoids, gycomol VN1, gycomol VN2, and gycomosides VN1-6 from the bioactive n-butanol fraction. The structures of these compounds were elucidated by one- and two-dimensional nuclear magnetic resonance spectroscopy, high-resolution electrospray ionisation mass spectrometry, and chemical methods. All isolated compounds were evaluated for their 5'-adenosine monophosphate-activated protein kinase (AMPK) and acetyl-coenzyme A carboxylase (ACC) activation effects on 3T3-L1 cells. Importantly, gycomol VN2, gycomoside VN1, and gycomosides VN3-5 activated the phosphorylation of AMPK and its downstream substrate ACC in 3T3-L1 cells at a dose of 10 μM. These effects imply that the activation of AMPK and ACC by active compounds from G. compressum has considerable potential for the prevention of obesity and its related disorders by activating AMPK signaling pathways.

Keywords:  3T3-L1 cells; AMPK and ACC activation; Cucurbitaceae; Dammarane-type triterpenoid; Gycomols; Gycomosides; Gynostemma compressum X. X. chen & D. R. liang

DOI:  https://doi.org/10.1016/j.phytochem.2022.113218
FEBS J. 2022 May 01.

Substrate recognition by Arg/Pro-rich insert domain in calcium/calmodulin-dependent protein kinase kinase for target protein kinases.

Riku Kaneshige, Satomi Ohtsuka, Yuhei Harada, Issei Kawamata, Masaki Magari, Naoki Kanayama, Naoya Hatano, Hiroyuki Sakagami, Hiroshi Tokumitsu.

  Calcium/calmodulin-dependent protein kinase kinases (CaMKKs) activate CaMKI, CaMKIV, protein kinase B/Akt, AMP-activated protein kinase (AMPK) by phosphorylating Thr residues in activation loops to mediate various Ca2+ -signaling pathways. Mammalian cells expressing CaMKKα and CaMKKβ lacking Arg/Pro-rich insert domain (RP-domain) sequences showed impaired phosphorylation of AMPKα, CaMKIα, and CaMKIV, whereas the autophosphorylation activities of CaMKK mutants remained intact and were similar to those of wild type CaMKKs. Liver kinase B1 (LKB1, an AMPK kinase) complexed with STRAD and MO25 and was unable to phosphorylate CaMKIα and CaMKIV; however, mutant LKB1 with the RP-domain sequences of CaMKKα and CaMKKβ inserted between kinase subdomains II and III acquired CaMKIα and CaMKIV phosphorylating activity in vitro and in transfected cultured cells. Furthermore, ionomycin-induced phosphorylation of hemagglutinin (HA)-CaMKIα at Thr177, HA-CaMKIV at Thr196, and HA-AMPKα at Thr172 in transfected cells was significantly suppressed by cotransfection of kinase-dead mutants of CaMKK isoforms, but these dominant-negative effects were abrogated with RP-deletion mutants, suggesting that sequestration of substrate kinases by loss-of-function CaMKK mutants requires the RP-domain. This was confirmed by pulldown experiments that showed that dominant-negative mutants of CaMKKα and CaMKKβ interact with target kinases but not RP-deletion mutants. Taken together, these results clearly indicate that both CaMKK isoforms require the RP-domain to recognize downstream kinases to interact with and phosphorylate Thr residues in their activation loops. Thus, the RP-domain may be a promising target for specific CaMKK inhibitors.

Keywords:  AMP-activated kinase; Arg/Pro-rich insert domain (RP-domain); calcium/calmodulin-dependent protein kinase; calcium/calmodulin-dependent protein kinase kinase; substrate recognition

DOI:  https://doi.org/10.1111/febs.16467
PLoS One. 2022 ;17(5): e0266472

AMP activated kinase negatively regulates hepatic Fetuin-A via p38 MAPK-C/EBPβ/E3 Ubiquitin Ligase Signaling pathway.

Vishal Kothari, Jeganathan Ramesh Babu, Suresh T Mathews.

Fetuin-A (Fet-A) is a liver-secreted phosphorylated protein, known to impair insulin signaling, which has been shown to be associated with obesity, insulin resistance, and incident diabetes. Fet-A interacts with the insulin-stimulated insulin receptor (IR) and inhibits IR tyrosine kinase activity and glucose uptake. It has been shown that high glucose increases Fet-A expression through the ERK1/2 signaling pathway. However, factors that downregulate Fet-A expression and their potential mechanisms are unclear. We examined the effect of AMP-activated protein kinase (AMPK) on high-glucose induced Fet-A expression in HepG2 cells, Hep3B cells and primary rat hepatocytes. High glucose increased Fet-A and phosphorylated (Ser312) fetuin-A (pFet-A) expression, which are known to impair insulin signaling. AICAR-induced AMPK activation significantly down-regulated high glucose-induced Fet-A expression and secretion of pFet-A while treatment with Compound C (AMPK inhibitor), SB202190 (p38 MAPK inhibitor) or p38 MAPK siRNA transfection prevented AICAR-induced downregulation of Fet-A expression. In addition, activation of p38 MAPK, by anisomycin, decreased the hepatic expression of Fet-A. Further, we our studies have shown that short-term effect of AICAR-treatment on Fet-A expression was mediated by proteosomal degradation, and long-term treatment of AICAR was associated with decrease in hepatic expression of C/EBP beta, an important transcription factor involved in the regulation of Fet-A. Taken together, our studies implicate a critical role for AMPK-p38 MAPK-C/EBPb-ubiquitin-proteosomal axis in the regulation of the expression of hepatic Fet-A.

DOI: https://doi.org/10.1371/journal.pone.0266472
Bosn J Basic Med Sci. 2022 Apr 29.

LKB1 suppression promotes cardiomyocyte regeneration via LKB1-AMPK-YAP axis.

Shuang Qu, Qiao Liao, Cheng Yu, Yue Chen, Han Luo, Xuewei Xia, Duofen He, Zaicheng Xu, Pedro A Jose, Zhuxin Li, Wei Eric Wang, Qing Rex Lyu, Chunyu Zeng.

The regenerative potential of cardiomyocytes in adult mammals is limited. Previous studies reported that cardiomyocyte proliferation is suppressed by AMP-activated protein kinase (AMPK). The role of liver kinase B1 (LKB1), as the major upstream kinase for AMPK, on cardiomyocyte proliferation is unclear. In this study, we found that the LKB1 levels rapidly increased after birth. With loss- and gain-of-function study, our data demonstrated that LKB1 levels negatively correlate with cardiomyocyte proliferation. We next identified Yes-associated protein (YAP) as the downstream effector of LKB1 using high-throughput RNA sequencing. Our results also demonstrated that AMPK plays an essential role in Lkb1 knockdown-induced cardiomyocyte proliferation. Importantly, deactivated AMPK abolished the LKB1-mediated regulation of YAP nuclear translocation and cardiomyocyte proliferation. Thus, our findings suggested the role of LKB1-AMPK-YAP axis during cardiomyocyte proliferation, which could be used as a potential target for inducing cardiac regeneration after injury.

DOI: https://doi.org/10.17305/bjbms.2021.7225
Front Nutr. 2022 ;9 849684

Maternal High-Fat Diet Impairs Placental Fatty Acid β-Oxidation and Metabolic Homeostasis in the Offspring.

Ling Zhang, Ziwei Wang, Honghua Wu, Ying Gao, Jia Zheng, Junqing Zhang.

  Maternal overnutrition can affect fetal growth and development, thus increasing susceptibility to obesity and diabetes in later life of the offspring. Placenta is the central organ connecting the developing fetus with the maternal environment. It is indicated placental fatty acid metabolism plays an essential role in affecting the outcome of the pregnancy and fetus. However, the role of placental fatty acid β-oxidation (FAO) in maternal overnutrition affecting glucose metabolism in the offspring remains unclear. In this study, C57BL/6J female mice were fed with normal chow or high-fat diet before and during pregnancy and lactation. The placenta and fetal liver were collected at gestation day 18.5, and the offspring's liver was collected at weaning. FAO-related genes and AMP-activated protein kinase (AMPK) signaling pathway were examined both in the placenta and in the human JEG-3 trophoblast cells. FAO-related genes were further examined in the liver of the fetuses and in the offspring at weaning. We found that dams fed with high-fat diet showed higher fasting blood glucose, impaired glucose tolerance at gestation day 14.5 and higher serum total cholesterol (T-CHO) at gestation day 18.5. The placental weight and lipid deposition were significantly increased in maternal high-fat diet group. At weaning, the offspring mice of high-fat diet group exhibited higher body weight, impaired glucose tolerance, insulin resistance and increased serum T-CHO, compared with control group. We further found that maternal high-fat diet downregulated mRNA and protein expressions of carnitine palmitoyltransferase 2 (CPT2), a key enzyme in FAO, by suppressing the AMPK/Sirt1/PGC1α signaling pathway in the placenta. In JEG-3 cells, protein expressions of CPT2 and CPT1b were both downregulated by suppressing the AMPK/Sirt1/PGC1α signaling pathway under glucolipotoxic condition, but were later restored by the AMPK agonist 5-aminoimidazole-4-carboxyamide ribonucleoside (AICAR). However, there was no difference in CPT2 and CPT1 gene expression in the liver of fetuses and offspring at weaning age. In conclusion, maternal high-fat diet can impair gene expression involved in FAO in the placenta by downregulating the AMPK signaling pathway, and can cause glucose and lipid dysfunction of offspring at weaning, indicating that placental FAO may play a crucial role in regulating maternal overnutrition and metabolic health in the offspring.

Keywords:  AMPK; fatty acid β-oxidation; maternal high-fat diet; offspring; placenta

DOI:  https://doi.org/10.3389/fnut.2022.849684
Food Funct. 2022 May 03.

Metabolic regulation of (-)-epicatechin and the colonic metabolite 2,3-dihydroxybenzoic acid on the glucose uptake, lipid accumulation and insulin signalling in cardiac H9c2 cells.

Esther García-Díez, María Elvira López-Oliva, Jara Pérez-Jiménez, María Angeles Martín, Sonia Ramos.

Epicatechin (EC) and main colonic phenolic acids derived from flavonoid intake have been suggested to exert healthful effects, although their mechanism of action remains unknown. Heart damage is highly prevalent in metabolic diseases, and the failure of this organ is a major cause of death worldwide. In this study, the modulation of the energy metabolism and insulin signalling by the mentioned compounds in cardiac H9c2 cells was evaluated. Incubation of cells with EC (1-20 μM) and 2,3-dihydroxybenzoic acid (DHBA, 10 μM) reduced glucose uptake, and both compounds decreased lipid accumulation at concentrations higher than 0.5 μM. EC and DHBA also increased the tyrosine phosphorylated and total insulin receptor (IR) levels, and activated the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) pathway in cardiac H9c2 cells. Interestingly, EC and DHBA did not modify glucose transporters (SGLT-1 and GLUT-1) levels, and increased GLUT-4 values. In addition, EC and DHBA decreased cluster of differentiation 36 (CD36) and fatty acid synthase (FAS) values, and enhanced carnitine palmitoyl transferase 1 (CPT1) and proliferator activated receptor α (PPARα) levels. By using specific inhibitors of AKT and 5'-AMP-activated protein kinase (AMPK), the participation of both proteins in EC- and DHBA-mediated regulation on glucose uptake and lipid accumulation was shown. Taken together, EC and DHBA modulate glucose uptake and lipid accumulation via AKT and AMPK, and reinforce the insulin signalling by activating key proteins of this pathway in H9c2 cells.

DOI: https://doi.org/10.1039/d2fo00182a
J Pharmacol Sci. 2022 Jun;pii: S1347-8613(22)00022-6. [Epub ahead of print]149(2): 37-45

Metformin suppresses epithelial sodium channel hyperactivation and its associated phenotypes in a mouse model of obstructive lung diseases.

Ryunosuke Nakashima, Hirofumi Nohara, Noriki Takahashi, Aoi Nasu, Megumi Hayashi, Tomoki Kishimoto, Shunsuke Kamei, Haruka Fujikawa, Kasumi Maruta, Taisei Kawakami, Yuka Eto, Keiko Ueno-Shuto, Mary Ann Suico, Hirofumi Kai, Tsuyoshi Shuto.

  Chronic obstructive pulmonary disease (COPD) is one of the leading causes of death in the world, and has no radical treatment. Inhibition of amiloride-sensitive epithelial sodium ion channel (ENaC) has now been considered as a potential therapeutic target against COPD. One possible modulator of ENaC is AMP-activated protein kinase (AMPK), a key molecule that controls a wide variety of cellular signals; however, little is known about whether metformin, a clinically available AMPK activator, has a protective role against ENaC-associated chronic pulmonary phenotypes, such as emphysema and pulmonary dysfunction. We first used ENaC-overexpressing human bronchial epithelial cells (β/γENaC-16HBE14o-) and identified that Metformin significantly reduced ENaC activity. Consistently, in vivo treatment of ENaC-overexpressing COPD mouse model (C57BL/6-βENaC-Tg mice) showed improvement of emphysema and pulmonary dysfunction, without any detrimental effect on non-pulmonary parameters (blood glucose level etc.). Bronchoalveolar lavage fluid (BALF) and lung tissue analyses revealed significant suppression in the infiltration of neutrophils as well as the expression of inflammatory markers (KC), neutrophil gelatinase (MMP9) and macrophage elastase (MMP12) in metformin-treated C57BL/6-βENaC-Tg mice. Overall, the present study demonstrates that metformin directly inhibits ENaC activity in vitro and provides the first evidence of therapeutical benefit of Metformin for COPD with higher ENaC activity.

Keywords:  AMP-Activated protein kinase (AMPK); Chronic obstructive pulmonary disease (COPD); Epithelial Na(+) channel (ENaC); Metformin

DOI:  https://doi.org/10.1016/j.jphs.2022.03.002
J Ginseng Res. 2022 Mar;46(2): 255-265

Cardioprotective effect of ginsenoside Rb1 via regulating metabolomics profiling and AMP-activated protein kinase-dependent mitophagy.

Jingui Hu, Ling Zhang, Fei Fu, Qiong Lai, Lu Zhang, Tao Liu, Boyang Yu, Junping Kou, Fang Li.

  Background: Ginsenoside Rb1, a bioactive component isolated from the Panax ginseng, acts as a remedy to prevent myocardial injury. However, it is obscure whether the cardioprotective functions of Rb1 are related to the regulation of endogenous metabolites, and its potential molecular mechanism still needs further clarification, especially from a comprehensive metabolomics profiling perspective.Methods: The mice model of acute myocardial ischemia (AMI) and oxygen glucose deprivation (OGD)-induced cardiomyocytes injury were applied to explore the protective effect and mechanism of Rb1. Meanwhile, the comprehensive metabolomics profiling was conducted by high-performance liquid chromatography and quadrupole time-of-flight mass spectrometry (HPLC-Q/TOF-MS) and a tandem liquid chromatography and mass spectrometry (LC-MS).
Results: Rb1 treatment profoundly reduced the infarct size and attenuated myocardial injury. The metabolic network map of 65 differential endogenous metabolites was constructed and provided a new inspiration for the treatment of AMI by Rb1, which was mainly associated with mitophagy. In vivo and in vitro experiments, Rb1 was found to improve mitochondrial morphology, mitochondrial function and promote mitophagy. Interestingly, the mitophagy inhibitor partly attenuated the cardioprotective effect of Rb1. Additionally, Rb1 markedly facilitated the phosphorylation of AMP-activated protein kinase α (AMPKα), and AMPK inhibition partially weakened the role of Rb1 in promoting mitophagy.
Conclusions: Ginsenoside Rb1 protects acute myocardial ischemia injury through promoting mitophagy via AMPKα phosphorylation, which might lay the foundation for the further application of Rb1 in cardiovascular diseases.

Keywords:  AMPK; Acute myocardial ischemia; Ginsenoside Rb1; Metabolomics; Mitophagy

DOI:  https://doi.org/10.1016/j.jgr.2021.06.011
J Cell Mol Med. 2022 May 02.

IM156, a new AMPK activator, protects against polymicrobial sepsis.

Ji Hyeon Kang, Sung Kyun Lee, Nam Joo Yun, Ye Seon Kim, Jason Jungsik Song, Yoe-Sik Bae.

  IM156, a novel biguanide with higher potency of AMP-activated protein kinase activation than metformin, has inhibitory activity against angiogenesis and cancer. In this study, we investigated effects of IM156 against polymicrobial sepsis. Administration of IM156 significantly increased survival rate against caecal ligation and puncture (CLP)-induced sepsis. Mechanistically, IM156 markedly reduced viable bacterial burden in the peritoneal fluid and peripheral blood and attenuated organ damage in a CLP-induced sepsis model. IM156 also inhibited the apoptosis of splenocytes and the production of inflammatory cytokines including IL-1β, IL-6 and IL-10 in CLP mice. Moreover, IM156 strongly inhibited the generation of reactive oxygen species and subsequent formation of neutrophil extracellular traps in response to lipopolysaccharide in neutrophils. Taken together, these results show that IM156 can inhibit inflammatory response and protect against polymicrobial sepsis, suggesting that IM156 might be a new treatment for sepsis.

Keywords:  AMP-activated protein kinase; IM156; caecal ligation and puncture; neutrophil extracellular traps; sepsis

DOI:  https://doi.org/10.1111/jcmm.17341
Am J Physiol Regul Integr Comp Physiol. 2022 May 03.

The sex-specific role of sensory neuron LKB1 on metabolic stress-induced mechanical hypersensitivity and mitochondrial respiration.

Katherine Marie Garner, Michael D Burton.

  Pain disorders induce metabolic stress in peripheral sensory neurons by reducing mitochondrial output, shifting cellular metabolism, and altering energy use. These processes implicate neuronal metabolism as an avenue for creating novel therapeutics. Liver kinase B1 (LKB1) mediates the cellular response to metabolic stress by inducing the AMPK pathway. The LKB1-AMPK pathway increases energy producing processes, including mitochondrial output. These processes inhibit pain by directly or indirectly restoring energetic balance within a cell. Although the LKB1-AMPK pathway has been linked to pain relief, it is not yet known which cell is responsible for this property, as well any direct ties to cellular metabolism. To elucidate this, we developed a genetic mouse model where LKB1 is selectively removed from Nav1.8-pain sensory neurons and metabolically stressed them by fasting for 24 hours. We found females, but not males, had neuron-specific, LKB1-dependent restoration of metabolic stress-induced mitochondrial metabolism. This was reflected in mechanical hypersensitivity, where the absence of LKB1 led to hypersensitivity in female, but not male, animals. This discrepancy suggests a sex- and cell-specific contribution to LKB1-depdendent fasting-induced mechanical hypersensitivity. While our data represent a potential role for LKB1 in anti-pain pathways in a metabolic-specific manner, more must be done to investigate these sex differences.

Keywords:  LKB1; cell metabolism; fasting; mechanical hypersensitivity; sensory neuron

DOI:  https://doi.org/10.1152/ajpregu.00279.2021
J Ginseng Res. 2022 Mar;46(2): 235-247

Ginsenoside Rg3 ameliorates myocardial glucose metabolism and insulin resistance via activating the AMPK signaling pathway.

Jingyu Ni, Zhihao Liu, Miaomiao Jiang, Lan Li, Jie Deng, Xiaodan Wang, Jing Su, Yan Zhu, Feng He, Jingyuan Mao, Xiumei Gao, Guanwei Fan.

  Background: Ginsenoside Rg3 is one of the main active ingredients in ginseng. Here, we aimed to confirm its protective effect on the heart function in transverse aortic coarctation (TAC)-induced heart failure mice and explore the potential molecular mechanisms involved.Methods: The effects of ginsenoside Rg3 on heart and mitochondrial function were investigated by treating TAC-induced heart failure in mice. The mechanism of ginsenoside Rg3 for improving heart and mitochondrial function in mice with heart failure was predicted through integrative analysis of the proteome and plasma metabolome. Glucose uptake and myocardial insulin sensitivity were evaluated using micro-positron emission tomography. The effect of ginsenoside Rg3 on myocardial insulin sensitivity was clarified by combining in vivo animal experiments and in vitro cell experiments.
Results: Treatment of TAC-induced mouse models with ginsenoside Rg3 significantly improved heart function and protected mitochondrial structure and function. Fusion of metabolomics, proteomics, and targeted metabolomics data showed that Rg3 regulated the glycolysis process, and Rg3 not only regulated glucose uptake but also improve myocardial insulin resistance. The molecular mechanism of ginsenoside Rg3 regulation of glucose metabolism was determined by exploring the interaction pathways of AMPK, insulin resistance, and glucose metabolism. The effect of ginsenoside Rg3 on the promotion of glucose uptake in IR-H9c2 cells by AMPK activation was dependent on the insulin signaling pathway.
Conclusions: Ginsenoside Rg3 modulates glucose metabolism and significantly ameliorates insulin resistance through activation of the AMPK pathway.

Keywords:  AMPK; Ginsenoside Rg3; Glucose metabolism; Heart failure; Insulin resistance

DOI:  https://doi.org/10.1016/j.jgr.2021.06.001
J Nutr Sci Vitaminol (Tokyo). 2022 ;68(2): 140-147

Plasmalogen Inhibits Body Weight Gain by Activating Brown Adipose Tissue and Improving White Adipose Tissue Metabolism.

Misa Hayashi, Maya Kudo, Ming Gao.

  Plasmalogen, a phospholipid, exhibits preventive and therapeutic effects on dementia. Phospholipids improve fat metabolism, but it is unknown whether plasmalogen has an effect on fat metabolism. In this study, the effects of plasmalogen were determined by administering plasmalogen to KK-Ay mice. As a result, weight gain was significantly suppressed in the plasmalogen-treated group compared with the control group from 7 wk after the start of administration. In addition, plasmalogen administration increased uncoupling protein 1 (UCP1) expression in brown adipose tissue. The effect is thought to result from liver kinase B1 (LKB1)/AMP-activated protein kinase (AMPK)/PR domain containing 16 (PRDM16)/peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) pathway activation via adrenergic β3 receptors. Furthermore, the expression of the carnitine palmitoyltransferase-1 (CPT-1) gene associated with thermogenic factors and β-oxidation was increased. We investigated the browning of white adipose tissue, but no increase in UCP1 gene expression was observed in perirenal adipose tissue, epididymis adipose tissue, mesenteric adipose tissue and inguinal region white adipose tissue. In contrast, plasmalogen increased the activity of AMPK, which is a central enzyme in lipid metabolism, in perirenal adipose tissue. Furthermore, the activity of the protein kinase A (PKA)/LKB1/AMPK/acetyl-coenzyme A carboxylase (ACC), stearoyl-CoA desaturase-1 (SCD-1), and hormone-sensitive lipase (HSL) pathways was confirmed. Plasmalogen may inhibit weight gain by activating brown fat to increase heat production, inhibiting lipid synthesis, and promoting lipolysis in white fat.

Keywords:  AMPK; BAT; UCP1; WAT; plasmalogen

DOI:  https://doi.org/10.3177/jnsv.68.140
IUBMB Life. 2022 May 05.

Ferulic acid ameliorates acetaminophen-induced acute liver injury by promoting AMPK-mediated protective autophagy.

Jianzhi Wu, Fei Zhou, Guifang Fan, Jia Liu, Yao Wang, Xiaoyong Xue, Xiangjun Lyu, Sheng Lin, Xiaojiaoyang Li.

  Acetaminophen (APAP), one of the most widely used antipyretics and analgesics, principally results in acute liver injury (ALI) in developed countries when taken overdose. Ferulic acid (FA) is a natural polyphenol compound existing in many plants that has free radical scavenging, anti-inflammatory and liver-protective properties. However, the effect and underlying mechanism of FA in treating APAP-induced ALI have not been fully elucidated. Herein, we established a mouse model of APAP-induced ALI and used APAP-stimulated mouse primary hepatocytes for biochemical assessment of molecular parameters. After constructing networks and obtaining predicted targets from public databases, we further verified the putative pathways using immune-blotting assays both in vivo and in vitro. The reign of liver necrosis, serum levels of ALT and AST and oxidative stress in livers significantly elevated after APAP treatment, which were almost recovered back to normal levels by FA administration. In addition, FA significantly upregulated the APAP-induced downregulation of hepatic specific markers, including HNF4a, Foxa2 and ALB. Then, the results of functional enrichment indicated the possible signaling pathways of FA against APAP challenge, mainly including AMPK, autophagy, apoptosis and other metabolic process. Furthermore, FA markedly reversed the APAP-induced decline of mitochondria membrane potential, increased ratio of BAX/BCL2 and CASPASE 3 expression, and promoted autophagy flux of hepatocytes by upregulating AMPK phosphorylation, which were abrogated by a specific AMPK inhibitor, compound C. Overall, the hepatoprotective effect of FA on APAP-induced ALI might be associated with anti-oxidant and anti-apoptosis, which were at least partly attributed to AMPK-mediated protective autophagy.

Keywords:  AMPK; Ferulic acid; acetaminophen; autophagy; hepatocyte

DOI:  https://doi.org/10.1002/iub.2625
Vet Res. 2022 May 03. 53(1): 33

Porcine parvovirus triggers autophagy through the AMPK/Raptor/mTOR pathway to promote viral replication in porcine placental trophoblasts.

Xiujuan Zhang, Peipei Ma, Ting Shao, Yingli Xiong, Qian Du, Songbiao Chen, Bichen Miao, Xuezhi Zhang, Xiaoya Wang, Yong Huang, Dewen Tong.

  Autophagy has been demonstrated to play important roles in the infection and pathogenesis of many viruses. We previously found that porcine parvovirus (PPV) infection can induce autophagy in porcine placental trophoblast cells (PTCs), but its underlying mechanism has not yet been fully revealed. In this study, we showed that PPV infection inhibited the activation of mTORC1 and promoted the expression of Beclin 1 and LC3II in PTCs. Treatment with a mTOR activator inhibited the expression of Beclin 1 and LC3II, as well as autophagy formation, and reduced viral replication in PPV-infected PTCs. Furthermore, we found that inhibition of AMPK expression, but not the inhibition of PI3K/Akt, p53, or MAPK/ERK1/2 pathway activation, can significantly increase mTOR phosphorylation in PPV-infected PTCs. Then, we found that the regulation of mTOR phosphorylation by AMPK was mediated by Raptor. AMPK expression knockout inhibited the activation of Raptor, decreased the expression of Beclin 1 and LC3II, suppressed the formation of autophagosomes, and reduced viral replication during PPV infection. Together, our results showed that PPV infection induces autophagy to promote viral replication by inhibiting the activation of mTORC1 through activation of the AMPK/Raptor pathway. These findings provide information to understand the molecular mechanisms of PPV-induced autophagy.

Keywords:  Porcine parvovirus; autophagy; placental trophoblast cells; signalling pathway

DOI:  https://doi.org/10.1186/s13567-022-01048-7
Neurochem Res. 2022 May 07.

Kaempferol Mediated AMPK/mTOR Signal Pathway Has a Protective Effect on Cerebral Ischemic-Reperfusion Injury in Rats by Inducing Autophagy.

Yajing Yuan, Fei Xia, Rong Gao, Yang Chen, Yu Zhang, Zhongping Cheng, Hongwei Zhao, Liming Xu.

  Ischemia/reperfusion (I/R) caused by ischemic stroke treatments leads to brain injury and its pathological mechanism is related to autophagy. The underlying mechanism of kaempferol on cerebral I/R injury needs to be explored. To establish I/R injury, we used a middle cerebral artery occlusion-reperfusion (MCAO) model in rats. MCAO rats were treated with the same amount of saline (I/R group); Treatment group rats were treated orally with kaempferol (50, 100, 200 mg/kg) for 7 days before surgery. After reperfusion for 24 h, the scores of neurological deficits and infarct volume in each group were evaluated. LC3, Beclin-1 p62, AMPK and mTOR protein expression levels were examined by TTC staining, immunofluorescence staining, qRT-PCR and western blotting assay. H&E and TTC staining showed that compared with model group, the infarction size of rats in kaempferol group was markedly reduced. Meanwhile, the results showed that kaempferol had a dose-dependent nerve function repairability. Nissl and TUNEL staining showed that kaempferol could reduce neuronal apoptosis and ameliorate neuronal impairment after I/R. Western blotting and qRT-PCR results showed that kaempferol could protect the brain from ischemia reperfusion by activating autophagy. In addition, add AMPK inhibitor, western blotting and immumohistochemical staining showed that kaempferol mediated AMPK/mTOR signal pathway in MCAO rats. Kaempferol could mediate the AMPK signal pathway to regulate autophagy and inhibit apoptosis to protect brain against I/R injury.

Keywords:  Apoptosis; Autophagy; Kaempferol; Middle cerebral artery occlusion (MCAO)

DOI:  https://doi.org/10.1007/s11064-022-03604-1
Biol Trace Elem Res. 2022 May 02.

Selenium-Enriched Probiotic Alleviates Western Diet-Induced Non-alcoholic Fatty Liver Disease in Rats via Modulation of Autophagy Through AMPK/SIRT-1 Pathway.

Rajat Pant, Nisha Sharma, Shaheen Wasil Kabeer, Shivam Sharma, Kulbhushan Tikoo.

  Current study was aimed to investigate the ability of L.acidophilus SNZ 86 to biotransform inorganic selenium to a more active organic form, resulting in trace element enrichment. Selenium-enriched L. acidophilus SNZ 86 has been shown to be effective in the treatment of a variety of gastrointestinal illnesses, indicating the need for additional research to determine the full potential of this therapeutic strategy in the treatment of metabolic disorders. Herein, we employed the western style diet-induced model of non-alcoholic fatty liver disease (NAFLD) to explore the therapeutic effect of selenium-enriched probiotic (SP). Male Sprague Dawley rats (160-180 g) were fed a high-fat (58% Kcal of fat) and high-fructose (30% w/v) diet for 12 weeks to develop an animal model mimicking NAFLD. High-fat and High-fructose diet-fed rats exhibited hyperglycemia, hyperlipidemia, insulin resistance, abnormal liver function test, increased hepatic oxidative stress, and steatosis. SP was then administered orally (L acidophilus 1 × 109 CFU/ml containing 0.4 g Se/day; p.o.) for 8 weeks. The selenium enrichment within L. acidophilus SNZ 86 was validated by TEM, which allowed for visualisation of the selenium deposition and size distribution in the probiotic. In NAFLD control rats, the expression of autophagy proteins (LC-3 A/B and Beclin), AMPK, and SIRT-1 was significantly reduced indicating downregulation of autophagy. However, supplementation of SP ameliorates hepatic steatosis as evidenced by improved biochemical markers and autophagic activation via upregulation of the AMPK and SIRT-1 pathway showing the relevance of autophagy in the disease aetiology. Collectively, these findings provide us with a better understanding of the role of SP in the treatment of hepatic steatosis and establish a therapeutic basis for potential clinical application of SP in the prevention of NAFLD and associated pathological conditions.

Keywords:  AMPK; Autophagy; Non-alcoholic fatty liver disease; SIRT-1; Selenium-enriched probiotic

DOI:  https://doi.org/10.1007/s12011-022-03247-x
Cell Death Discov. 2022 May 06. 8(1): 253

The AMPK-related kinase NUAK2 suppresses glutathione peroxidase 4 expression and promotes ferroptotic cell death in breast cancer cells.

Tanu Singh, Alexander Beatty, Jeffrey R Peterson.

Ferroptosis is a caspase-independent form of regulated cell death strongly linked to the accumulation of reactive lipid hydroperoxides. Lipid hydroperoxides are neutralized in cells by glutathione peroxidase 4 (GPX4) and inhibitors of GPX4 are potent ferroptosis inducers with therapeutic potential in cancer. Here we report that siRNA-mediated silencing of the AMPK-related kinase NUAK2 suppresses cell death by small-molecule inducers of ferroptosis but not apoptosis. Mechanistically we find that NUAK2 suppresses the expression of GPX4 at the RNA level and enhances ferroptosis triggered by GPX4 inhibitors in a manner independent of its kinase activity. NUAK2 is amplified along with MDM4 in a subset of breast cancers, particularly the claudin-low subset, suggesting that this may predict vulnerability to GPX4 inhibitors. These findings identify a novel pathway regulating GPX4 expression as well as ferroptotic sensitivity with potential as a biomarker of breast cancer patients that might respond to GPX4 inhibition as a therapeutic strategy.

DOI: https://doi.org/10.1038/s41420-022-01044-y
J Cachexia Sarcopenia Muscle. 2022 May 03.

Electrical stimulated GLUT4 signalling attenuates critical illness-associated muscle wasting.

Alex B Addinsall, Nicola Cacciani, Anders Backéus, Yvette Hedström, Ganna Shevchenko, Jonas Bergquist, Lars Larsson.

  BACKGROUND: Critical illness myopathy (CIM) is a debilitating condition characterized by the preferential loss of the motor protein myosin. CIM is a by-product of critical care, attributed to impaired recovery, long-term complications, and mortality. CIM pathophysiology is complex, heterogeneous and remains incompletely understood; however, loss of mechanical stimuli contributes to critical illness-associated muscle atrophy and weakness. Passive mechanical loading and electrical stimulation (ES) therapies augment muscle mass and function. While having beneficial outcomes, the mechanistic underpinning of these therapies is less known. Therefore, here we aimed to assess the mechanism by which chronic supramaximal ES ameliorates CIM in a unique experimental rat model of critical care.METHODS: Rats were subjected to 8 days of critical care conditions entailing deep sedation, controlled mechanical ventilation, and immobilization with and without direct soleus ES. Muscle size and function were assessed at the single cell level. RNAseq and western blotting were employed to understand the mechanisms driving ES muscle outcomes in CIM.
RESULTS: Following 8 days of controlled mechanical ventilation and immobilization, soleus muscle mass, myosin : actin ratio, and single muscle fibre maximum force normalized to cross-sectional area (CSA; specific force) were reduced by 40-50% (P < 0.0001). ES significantly reduced the loss of soleus muscle fibre CSA and myosin : actin ratio by approximately 30% (P < 0.05) yet failed to effect specific force. RNAseq pathway analysis revealed downregulation of insulin signalling in the soleus muscle following critical care, and GLUT4 trafficking was reduced by 55% leading to an 85% reduction of muscle glycogen content (P < 0.01). ES promoted phosphofructokinase and insulin signalling pathways to control levels (P < 0.05), consistent with the maintenance of GLUT4 translocation and glycogen levels. AMPK, but not AKT, signalling pathway was stimulated following ES, where the downstream target TBC1D4 increased 3 logFC (P = 0.029) and AMPK-specific P-TBC1D4 levels were increased approximately two-fold (P = 0.06). Reduction of muscle protein degradation rather than increased synthesis promoted soleus CSA, as ES reduced E3 ubiquitin proteins, Atrogin-1 (P = 0.006) and MuRF1 (P = 0.08) by approximately 50%, downstream of AMPK-FoxO3.
CONCLUSIONS: ES maintained GLUT4 translocation through increased AMPK-TBC1D4 signalling leading to improved muscle glucose homeostasis. Soleus CSA and myosin content was promoted through reduced protein degradation via AMPK-FoxO3 E3 ligases, Atrogin-1 and MuRF1. These results demonstrate chronic supramaximal ES reduces critical care associated muscle wasting, preserved glucose signalling, and reduced muscle protein degradation in CIM.

Keywords:  Critical illness myopathy; E3 ligase; GLUT4 signalling; Muscle wasting; TBC1D4

DOI:  https://doi.org/10.1002/jcsm.12978
Toxicol Appl Pharmacol. 2022 Apr 27. pii: S0041-008X(22)00182-X. [Epub ahead of print]444 116037

Mogrol suppresses lung cancer cell growth by activating AMPK-dependent autophagic death and inducing p53-dependent cell cycle arrest and apoptosis.

He Li, Linling Liu, Hong-Ying Chen, Xin Yan, Ru-Li Li, Jie Lan, Kun-Yue Xue, Xue Li, Cai-Li Zhuo, Lan Lin, Ling-Yu Li, Zhuang Wu, Die Zhang, Xue-Mei Wang, Wen-Jing Huang, Yingling Wang, Wei Jiang, Liming Zhou.

  Lung carcinoma is the leading cause of cancer-related death worldwide. Chemotherapy remains the cornerstone of lung cancer treatment. Unfortunately, most types of cancer will develop resistance to chemotherapies over the time. One of the efforts to prevent the chemotherapy resistance is to find alternative chemotherapy drugs. Mogrol has been found to have antitumor activity. However, little is known about the pharmacological mechanisms underlying the suppression of mogrol on lung cancers. In this study, we observed that mogrol exposure significantly reduced the tumor volume and weight in tumor-bearing nude mice without obvious effect on body weight and cardiac function. Mogrol also significantly inhibited the proliferation and migration of lung cancer cells, including non-small-cell lung carcinoma cells, A549, H1299, H1975 and SK-MES-1 cells, with no obvious effect on control human bronchial epithelial cells (HBE). Further studies revealed that mogrol stirred excessive autophagy and autophagic flux, and finally, autophagic cell death, in lung cancer cells, which could be attenuated by autophagy inhibitors, 3-MA and chloroquine. Furthermore, mogrol significantly activated AMPK to induce autophagy and autophagic cell death, which could be abrogated by Compound C, an AMPK inhibitor. In addition, mogrol induced a significant increase in p53 activity in lung cancer cells, accompanied with cell cycle arrest and apoptosis, which could be weakened by p53 silence. Our results indicated that mogrol effectively suppressed lung cancer cells in vivo and in vitro by inducing the excessive autophagy and autophagic cell death via activating AMPK signaling pathway, as well as cell cycle arrest and apoptosis via activating p53 pathway.

Keywords:  Apoptosis; Autophagy; Cell cycle arrest; Lung cancer; Mogrol

DOI:  https://doi.org/10.1016/j.taap.2022.116037
Sci Rep. 2022 May 06. 12(1): 7415

Irisin protects cardiomyocytes against hypoxia/reoxygenation injury via attenuating AMPK mediated endoplasmic reticulum stress.

Rongchuan Yue, Mingming Lv, Meide Lan, Zaiyong Zheng, Xin Tan, Xuemei Zhao, Yulong Zhang, Jun Pu, Lei Xu, Houxiang Hu.

Endoplasmic reticulum (ER) stress plays a central role in myocardial ischemia/reperfusion (I/R) injury. Irisin has been reported to have protective properties in ischemia disease. In this study, we aimed at investigating whether irisin could alleviate myocardial I/R injury by ER stress attenuation. The in vitro model of hypoxia/reoxygenation (H/R) was established, which resembles I/R in vivo. Cell viability and apoptosis were estimated. Expressions of cleaved caspase-3, cytochrome c, GRP78, pAMPK, CHOP, and eIF2α were assessed by western blot. Our results revealed that pre-treatment with irisin significantly decreased cytochrome c release from mitochondria and caspase-3 activation caused by H/R. Irsin also reduced apoptosis and increased cell viability. These effects were abolished by AMPK inhibitor compound C pre-treatment. Also, GRP78 and CHOP expressions were up-regulated in the H/R group compared to the control group; however, irisin attenuated their expression. The pAMPK level was significantly decreased compared to the control, and this effect could be partly reversed by metformin pre-treatment. These results suggest that ER stress is associated with cell viability decreasing and cardiomyocytes apoptosis induced by H/R. Irisin could efficiently protect cardiomyocytes from H/R-injury via attenuating ER stress and ER stress-induced apoptosis.

DOI: https://doi.org/10.1038/s41598-022-11343-0
Biochimie. 2022 Apr 30. pii: S0300-9084(22)00109-2. [Epub ahead of print]

Regulation of apoptosis and autophagy by albendazole in human colon adenocarcinoma cells.

Young Yun Jung, Seung Ho Baek, In Jin Ha, Kwang Seok Ahn.

  Albendazole (ABZ) was initially introduced as an anthelmintic, however, many studies have reported with its anticancer effects. We investigated the anti-tumor effects of ABZ in vitro in human colon adenocarcinoma HCT-15, HCT-116, HT-29, and SW480 cell lines in this study. The cytotoxicity of ABZ was analyzed in colon adenocarcinoma cell lines and normal CCD18Co cells. We found that ABZ induced the subG1 arrest during cell cycle progression, increased the late apoptotic cells, shifted of peak TUNEL-labeled cells peak, and induced apoptosis. Then effects on autophagy activation was confirmed by acridine orange (AO), MDC staining, and immunocytochemistry of LC3. It was observed that ABZ can induce the autophagy activation through modulating the levels of LC3, Atg7, and beclin-1. For mechanistic studies, apoptosis blocker (Z-DEVD-FMK) and autophagy inhibitor (3-MA) were used to confirm that whether ABZ has apoptosis and autophagy specific effects, and reversal in both these cell death processes were noted. The effects of ABZ on AMPK, MAPKs, and ULK induction was also evaluated. We noticed that N-acetyl cysteine (NAC), a broad spectrum antioxidant, can effectively inhibit both apoptosis and autophagy. However, ABZ could even recover suppression of apoptosis and autophagy caused by NAC in colon cancer cells. Therefore, ABZ can potentially up-regulate both the apoptosis and autophagy to significantly suppress tumorigenesis in colorectal cancer cell lines.

Keywords:  AMPK; Albendazole; Apoptosis; Autophagy; Human colon adenocarcinoma; MAPKs

DOI:  https://doi.org/10.1016/j.biochi.2022.04.014
Comput Struct Biotechnol J. 2022 ;20 1860-1875

Identifying novel SMYD3 interactors on the trail of cancer hallmarks.

Candida Fasano, Martina Lepore Signorile, Katia De Marco, Giovanna Forte, Paola Sanese, Valentina Grossi, Cristiano Simone.

  SMYD3 overexpression in several human cancers highlights its crucial role in carcinogenesis. Nonetheless, SMYD3 specific activity in cancer development and progression is currently under debate. Taking advantage of a library of rare tripeptides, which we first tested for their in vitro binding affinity to SMYD3 and then used as in silico probes, we recently identified BRCA2, ATM, and CHK2 as direct SMYD3 interactors. To gain insight into novel SMYD3 cancer-related roles, here we performed a comprehensive in silico analysis to cluster all potential SMYD3-interacting proteins identified by screening the human proteome for the previously tested tripeptides, based on their involvement in cancer hallmarks. Remarkably, we identified mTOR, BLM, MET, AMPK, and p130 as new SMYD3 interactors implicated in cancer processes. Further studies are needed to characterize the functional mechanisms underlying these interactions. Still, these findings could be useful to devise novel therapeutic strategies based on the combined inhibition of SMYD3 and its newly identified molecular partners. Of note, our in silico methodology may be useful to search for unidentified interactors of other proteins of interest.

Keywords:  AMPK, 5′AMP-activated protein kinase; BLM, Bloom syndrome protein; CRC, colorectal cancer; EMT, epithelial-mesenchymal transition; GC, gastric cancer; Gastrointestinal cancer cell lines; H3K4, histone H3 lysine 4; H4K5, histone H4 lysine 5; HCC, hepatocellular carcinoma; HGF, hepatocyte growth factor; Hallmarks of cancer; In silico tripeptide screening; PC, pancreatic cancer; PPIs, protein–protein interactions; RB, retinoblastoma protein; SMYD3; SMYD3 interactome; SMYD3i, SMYD3 inhibitor; UCEC, uterine corpus endometrial carcinoma

DOI:  https://doi.org/10.1016/j.csbj.2022.03.037
Food Chem X. 2022 Mar 30. 13 100222

A comprehensive review on the glucoregulatory properties of food-derived bioactive peptides.

Forough Jahandideh, Stephane L Bourque, Jianping Wu.

  Diabetes mellitus, a group of metabolic disorders characterized by persistent hyperglycemia, affects millions of people worldwide and is on the rise. Dietary proteins, from a wide range of food sources, are rich in bioactive peptides with antidiabetic properties. Notable examples include AGFAGDDAPR, a black tea-derived peptide, VRIRLLQRFNKRS, a β-conglycinin-derived peptide, and milk-derived peptide VPP, which have shown antidiabetic effects in diabetic rodent models through variety of pathways including improving beta-cells function, suppression of alpha-cells proliferation, inhibiting food intake, increasing portal cholecystokinin concentration, enhancing insulin signaling and glucose uptake, and ameliorating adipose tissue inflammation. Despite the immense research on glucoregulatory properties of bioactive peptides, incorporation of these bioactive peptides in functional foods or nutraceuticals is widely limited due to the existence of several challenges in the field of peptide research and commercialization. Ongoing research in this field, however, is fundamental to pave the road for this purpose.

Keywords:  AMPK, AMP-activated protein kinase; Akt, Protein kinase B; Bioactive peptides; C/EBP-α, CCAAT/ enhancer binding protein alpha; CCK, Cholecystokinin; CCK-1R, CCK type 1 receptor; DPP-IV, Dipeptidyl peptidase IV; Diabetes mellitus; ERK1/2, Extracellular signal regulated kinase 1/2; GIP, Glucose-dependent insulinotropic polypeptide; GLP-1, Glucagon-like peptide 1; GLUT, Glucose transporter; Glucose homeostasis; IRS-1, Insulin receptor substrate-1; Insulin resistance; MAPK, Mitogen activated protein kinase; PI3K, Phosphatidylinositol 3-kinase; PPARγ, Peroxisome proliferator associated receptor gamma; Reproductive dysfunction; TZD, Thiazolidinedione; cGMP, cyclic guanosine-monophosphate

DOI:  https://doi.org/10.1016/j.fochx.2022.100222