bims-amsmem 2022-10-23 papers

bims-amsmem

Biomed News

on AMPK signaling mechanism in energy metabolism

Issue of 2022–10–23
ten papers selected by
Dipsikha Biswas, Københavns Universitet

Greater Phosphorylation of AMPK and Multiple AMPK Substrates in the Skeletal Muscle of 24 Month-old Calorie Restricted Compared to Ad Libitum Fed Male Rats.
Energy-Stress-Mediated AMPK Activation Promotes GPX4-Dependent Ferroptosis through the JAK2/STAT3/P53 Axis in Renal Cancer.
Role of AMPK in Myocardial Ischemia-Reperfusion Injury-Induced Cell Death in the Presence and Absence of Diabetes.
Breast milk mesenchymal stem cells abate cisplatin-induced cardiotoxicity in adult male albino rats via modulating the AMPK pathway.
Prostaglandin EP3 receptor activation is antinociceptive in sensory neurons via PI3Kγ, AMPK and GRK2.
Downregulation of hepatic ceruloplasmin ameliorates NAFLD via SCO1-AMPK-LKB1 complex.
Thymoquinone and quercetin protect against hepatic steatosis in association with SIRT1/AMPK stimulation and regulation of autophagy, perilipin-2, and cytosolic lipases.
Larotrectinib induces autophagic cell death through AMPK/mTOR signalling in colon cancer.
Glucose-6-phosphate dehydrogenase exerts anti-stress effects independently of its enzymatic activity.
AAV-ie-mediated UCP2 overexpression accelerates inner hair cell loss during aging in vivo.

J Gerontol A Biol Sci Med Sci. 2022 Oct 21. pii: glac218. [Epub ahead of print]

Greater Phosphorylation of AMPK and Multiple AMPK Substrates in the Skeletal Muscle of 24 Month-old Calorie Restricted Compared to Ad Libitum Fed Male Rats.

Amy Zheng, Seong Eun Kwak, Jesper B Birk, Edward B Arias, Dominic Thorley, Jørgen F P Wojtaszewski, Gregory D Cartee.

  AMP-activated protein kinase (AMPK), a highly conserved, heterotrimeric serine/threonine kinase with critical sensory and regulatory functions, is proposed to induce anti-aging actions of caloric restriction (CR). Although earlier studies assessed CR's effects on AMPK in rodent skeletal muscle, the scope of these studies was narrow with limited focus on older animals. This study's purpose was to fill important knowledge gaps related to CR's influence on AMPK in skeletal muscle of older animals. Therefore, using epitrochlearis muscles from 24 month-old ad libitum fed (AL) and CR (consuming 65% of AL intake for 8 weeks), male Fischer-344 x Brown Norway F1 rats, we determined: 1) AMPK Thr172 phosphorylation (a key regulatory site) by immunoblot; 2) AMPKα1 and AMPKα2 activity (representing the two catalytic α-subunits of AMPK), and AMPKγ3 activity (representing AMPK complexes that include the skeletal muscle-selective regulatory γ3 subunit) using enzymatic assays; 3) phosphorylation of multiple protein substrates that are linked to CR-related effects (acetyl CoA carboxylase, ACC, that regulates lipid oxidation; Beclin-1 and ULK1 that are autophagy regulatory proteins; Raptor, mTORC1 complex protein that regulates autophagy; TBC1D1 and TBC1D4 that regulate glucose uptake) by immunoblot; and 4) ATP and AMP concentrations (key AMPK regulators) by mass spectrometry. The results revealed significant CR-associated increases in the phosphorylation of AMPK Thr172 and four AMPK substrates (ACC, Beclin-1, TBC1D1, TBC1D4), without significant diet-related differences in ATP or AMP concentration or AMPKα1-, AMPKα2-, or AMPKγ3-associated activity. The enhanced phosphorylation of multiple AMPK substrates provides novel mechanistic insights linking AMPK to functionally important consequences of CR.

Keywords:  Beclin-1; TBC1D1; TBC1D4; ULK1; acetyl-CoA carboxylase

DOI:  https://doi.org/10.1093/gerona/glac218
Oxid Med Cell Longev. 2022 ;2022 2353115

Energy-Stress-Mediated AMPK Activation Promotes GPX4-Dependent Ferroptosis through the JAK2/STAT3/P53 Axis in Renal Cancer.

Yanze Li, Ye Zhang, Qiangmin Qiu, Lei Wang, Hu Mao, Juncheng Hu, Zhiyuan Chen, Yang Du, Xiuheng Liu.

Energy stress is an unfavorable condition that tumor cells are often exposed to. Ferroptosis is considered an emerging target for tumor therapy. However, the role of ferroptosis in energy stress in renal cancer is currently unknown. In this study, we found that glucose deprivation significantly enhanced GPX4-dependent ferroptosis through AMPK activation. Further, AMPK activation suppressed GPX4 expression at the transcriptional level through the upregulation of P53 expression. Additionally, the inactivation of JAK2/STAT3 transcriptionally promoted P53 expression, thereby promoting AMPK-mediated GPX4-dependent ferroptosis. In conclusion, energy stress promotes AMPK-mediated GPX4-dependent erastin-induced ferroptosis in renal cancer through the JAK2/STAT3/P53 signaling axis.

DOI: https://doi.org/10.1155/2022/2353115
Oxid Med Cell Longev. 2022 ;2022 7346699

Role of AMPK in Myocardial Ischemia-Reperfusion Injury-Induced Cell Death in the Presence and Absence of Diabetes.

Nirupama Kandula, Saurabh Kumar, Venkata Kiran Kumar Mandlem, Aneela Siddabathuni, Sanjay Singh, Ramoji Kosuru.

Recent studies indicate cell death is the hallmark of cardiac pathology in myocardial infarction and diabetes. The AMP-activated protein kinase (AMPK) signalling pathway is considered a putative salvaging phenomenon, plays a decisive role in almost all cellular, metabolic, and survival functions, and therefore entails precise regulation of its activity. AMPK regulates various programmed cell death depending on the stimuli and context, including autophagy, apoptosis, necroptosis, and ferroptosis. There is substantial evidence suggesting that AMPK is down-regulated in cardiac tissues of animals and humans with type 2 diabetes or metabolic syndrome compared to non-diabetic control and that stimulation of AMPK (physiological or pharmacological) can ameliorate diabetes-associated cardiovascular complications, such as myocardial ischemia-reperfusion injury. Furthermore, AMPK is an exciting therapeutic target for developing novel drug candidates to treat cell death in diabetes-associated myocardial ischemia-reperfusion injury. Therefore, in this review, we summarized how AMPK regulates autophagic, apoptotic, necroptotic, and ferroptosis pathways in the context of myocardial ischemia-reperfusion injury in the presence and absence of diabetes.

DOI: https://doi.org/10.1155/2022/7346699
Sci Rep. 2022 Oct 20. 12(1): 17554

Breast milk mesenchymal stem cells abate cisplatin-induced cardiotoxicity in adult male albino rats via modulating the AMPK pathway.

Mahitab M Nageeb, Sara F Saadawy, Seba Hassan Attia.

Myocardial injury influenced by cisplatin (Cis) is a compelling reason to hunt out a treatment modality to overcome such a threat in cisplatin-treated patients. Breast Milk mesenchymal stem cells (Br-MSCs) are a non-invasive, highly reproducible source of stem cells. Herein, we investigate Br-MSCs' role in cardiotoxicity induced by cisplatin. Rats were divided into; control, Cis-treated (received 12 mg/kg single intraperitoneal injection), BrMSCs-treated (received single intraperitoneal injection of 0.5 ml sterilized phosphate-buffered saline containing 2 × 107 cells of Br-MSCs); metformin-treated (received 250 mg/kg/day orally) and BrMSCs + metformin + Cis treated groups. At the experiment end, serum creatine kinase (CK-MB) and cardiac troponin T (cTnT) activates were estimated, cardiac malondialdehyde (MDA), superoxide dismutase (SOD), interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α) levels were measured, cardiac expression of Bax and Bcl-2 and AMP-activated protein kinase (AMPK), as well as heart histopathology, were evaluated. Study results showed that Cis explored acute cardiotoxicity evidenced by deteriorated cardiac indices, induction of oxidative stress, and inflammation with myocardium histological alterations. Treatment with Br-MSCs restored heart function and structure deteriorated by Cis injection. The antioxidant/anti-inflammatory/anti-apoptotic results of Br-MSCs were supported by AMPK activation denoting their protective role against cisplatin-induced cardiac injury. These results were superior when metformin was added to the treatment protocol.

DOI: https://doi.org/10.1038/s41598-022-22095-2
Br J Pharmacol. 2022 Oct 17.

Prostaglandin EP3 receptor activation is antinociceptive in sensory neurons via PI3Kγ, AMPK and GRK2.

Christian König, Andrea Ebersberger, Annett Eitner, Reinhard Wetzker, Hans-Georg Schaible.

   BACKGROUND AND PURPOSE: Prostaglandin E2 is classically considered a major mediator of inflammatory pain, by acting on neuronal Gs protein-coupled EP2 and EP4 receptors. However, the neuronal EP3 receptor, colocalized with EP2 and EP4 receptor, is Gi protein-coupled and antagonises the pronociceptive prostaglandin E2 effect. Here we investigated the cellular signalling mechanisms by which the EP3 receptor reduces EP2 and EP4 receptor-evoked pronociceptive effects in sensory neurons.
EXPERIMENTAL APPROACH: Experiments were performed on isolated and cultured dorsal root ganglion (DRG) neurons from wild type, phosphoinositide 3-kinase γ (PI3Kγ)-/- , and PI3Kγkinase dead (KD)/KD mice. For subtype-specific stimulations we used specific EP2, EP3, and EP4 receptor agonists from ONO Pharmaceuticals. As functional readout we recorded TTX-resistant sodium currents in patch-clamp experiments. Western blots were used to investigate the activation of intracellular signalling pathways. EP4 receptor internalization was measured using immunocytochemistry.
KEY RESULTS: Different pathways mediate the inhibition of EP2 and EP4 receptor-dependent pronociceptive effects by EP3 receptor stimulation. Inhibition of EP2 receptor-evoked pronociceptive effect critically depends on the kinase-independent function of the signalling protein PI3Kγ, and adenosine monophosphate activated protein kinase (AMPK) is involved. By contrast, inhibition of EP4 receptor-evoked pronociceptive effect is independent on PI3Kγ and mediated through activation of G protein-coupled receptor kinase 2 (GRK2) which enhances the internalization of the EP4 receptor after ligand binding.
CONCLUSION AND IMPLICATIONS: Activation of neuronal PI3Kγ, AMPK, and GRK2 by EP3 receptor activation limits cAMP-dependent pain generation by prostaglandin E2 . These new insights hold the potential for a novel approach in pain therapy.

Keywords:  EP3 receptor; GRK2; PGE2; PI3Kγ; antinociception; pain; sensory neuron

DOI:  https://doi.org/10.1111/bph.15971
Cell Rep. 2022 Oct 18. pii: S2211-1247(22)01348-1. [Epub ahead of print]41(3): 111498

Downregulation of hepatic ceruloplasmin ameliorates NAFLD via SCO1-AMPK-LKB1 complex.

Liping Xie, Yanmei Yuan, Simiao Xu, Sijia Lu, Jinyang Gu, Yanping Wang, Yibing Wang, Xianjing Zhang, Suzhen Chen, Jian Li, Junxi Lu, Honglin Sun, Ruixiang Hu, Hailong Piao, Wen Wang, Cunchuan Wang, Jing Wang, Na Li, Morris F White, Liu Han, Weiping Jia, Ji Miao, Junli Liu.

  Copper deficiency has emerged to be associated with various lipid metabolism diseases, including non-alcoholic fatty liver disease (NAFLD). However, the mechanisms that dictate the association between copper deficiency and metabolic diseases remain obscure. Here, we reveal that copper restoration caused by hepatic ceruloplasmin (Cp) ablation enhances lipid catabolism by promoting the assembly of copper-load SCO1-LKB1-AMPK complex. Overnutrition-mediated Cp elevation results in hepatic copper loss, whereas Cp ablation restores copper content to the normal level without eliciting detectable hepatotoxicity and ameliorates NAFLD in mice. Mechanistically, SCO1 constitutively interacts with LKB1 even in the absence of copper, and copper-loaded SCO1 directly tethers LKB1 to AMPK, thereby activating AMPK and consequently promoting mitochondrial biogenesis and fatty acid oxidation. Therefore, this study reveals a mechanism by which copper, as a signaling molecule, improves hepatic lipid catabolism, and it indicates that targeting copper-SCO1-AMPK signaling pathway ameliorates NAFLD development by modulating AMPK activity.

Keywords:  AMPK; CP: Metabolism; NAFLD; ceruloplasmin; copper sensing; fatty acid oxidation; metabolism; mitochondrial biogenesis

DOI:  https://doi.org/10.1016/j.celrep.2022.111498
Arch Physiol Biochem. 2022 Oct 20. 1-14

Thymoquinone and quercetin protect against hepatic steatosis in association with SIRT1/AMPK stimulation and regulation of autophagy, perilipin-2, and cytosolic lipases.

Hend Ashour, Laila A Rashed, Radwa T M Hassanein, Basma E Aboulhoda, Hasnaa A Ebrahim, Mohamed H Elsayed, Miran A Elkordy, Omaima M Abdelwahed.

   BACKGROUND: We sought to investigate thymoquinone (TQ)/quercetin combination in preventing hepatic steatosis (HS).
MATERIALS AND METHODS: The included rat groups; (1) Control, (2) HS model, (3) HS treated with TQ 10 mg.kg-1.d-1, (4) HS treated with quercetin 50 mg.kg-1.d-1, and (5) HS treated with both compounds for 4 weeks.
RESULTS: TQ/quercetin co-treatment augmented the anti-steatosis potential of each ingredient. The results revealed more (p < 0.001) sirtuin (SIRT1)/AMP-activated protein kinase (p-AMPK) upregulation compared to each treatment in line with autophagy protein Atg7 enhancement, and suppressed pro-inflammatory and oxidation markers. They diminished the hepatic lipogenic enzymes and perilipin-2 and activated the cytosolic lipases adipose triglyceride lipase (ATGL). Histological and Biochemical analysis revealed diminished lipid deposition and improved liver enzymes (alanine aminotransferase [ALT] and aspartate aminotransferase [AST]) compared to the data of separate treatments.
CONCLUSION: TQ and quercitin effectively upregulated SIRT1/p-AMPK and regulated hepatic perilipin-2/ATGL, inflammation and oxidative stress, preserved liver structure and function. TQ/quercetin combination additively prevents HS.

Keywords:  Hepatic steatosis; SIRT1/AMPK; autophagy/perilipin/ATGL; quercetin; thymoquinone

DOI:  https://doi.org/10.1080/13813455.2022.2134423
J Cell Mol Med. 2022 Oct 17.

Larotrectinib induces autophagic cell death through AMPK/mTOR signalling in colon cancer.

Wencheng Kong, Hangzhang Zhu, Sixing Zheng, Guang Yin, Panpan Yu, Yuqiang Shan, Xinchun Liu, Rongchao Ying, Hong Zhu, Shenglin Ma.

  Larotrectinib (Lar) is a highly selective and potent small-molecule inhibitor used in patients with tropomyosin receptor kinase (TRK) fusion-positive cancers, including colon cancer. However, the underlying molecular mechanisms specifically in patients with colon cancer have not yet been explored. Our data showed that Lar significantly suppressed proliferation and migration of colon cancer cells. In addition, Lar suppressed the epithelial-mesenchymal transition (EMT) process, as evidenced by elevation in E-cadherin (E-cad), and downregulation of vimentin and matrix metalloproteinase (MMP) 2/9 expression. Furthermore, Lar was found to activate autophagic flux, in which Lar increased the ratio between LC3II/LC3I and decreased the expression of p62 in colon cancer cells. More importantly, Lar also increased AMPK phosphorylation and suppressed mTOR phosphorylation in colon cancer cells. However, when we silenced AMPK in colon cancer cells, Lar-induced accumulation of autolysomes as well as Lar-induced suppression of the EMT process were significantly diminished. An in vivo assay also confirmed that tumour volume and weight decreased in Lar-treated mice than in control mice. Taken together, this study suggests that Lar significantly suppresses colon cancer proliferation and migration by activating AMPK/mTOR-mediated autophagic cell death.

Keywords:  AMPK/mTOR signalling; Larotrectinib; autophagy flux; colon cancer; epithelial-mesenchymal transition

DOI:  https://doi.org/10.1111/jcmm.17530
J Biol Chem. 2022 Oct 12. pii: S0021-9258(22)01030-4. [Epub ahead of print] 102587

Glucose-6-phosphate dehydrogenase exerts anti-stress effects independently of its enzymatic activity.

Xiaohan Jin, Xuexue Li, Lifang Li, Benfu Zhong, Yang Hong, Jing Niu, Binghui Li.

  G6PD (Glucose-6-phosphate dehydrogenase) is the rate-limiting enzyme in the oxPPP (oxidative pentose phosphate pathway) that can generate cytosolic NADPH for biosynthesis and oxidative defense. Since cytosolic NADPH can be compensatively produced by other sources, the enzymatic activity-deficiency alleles of G6PD are well tolerated in somatic cells, but the effect of null mutations is unclear. Herein, we show that G6PD knockout sensitizes cells to the stresses induced by hydrogen peroxide, superoxide, hypoxia, and the inhibition of the electron transport chain. This effect can be completely reversed by the expressions of natural mutants associated with G6PD deficiency, even without dehydrogenase activity, exactly like the wild type G6PD. Furthermore, we demonstrate that G6PD can physically interact with AMPK (AMPK-activated protein kinase) to facilitate its activity, and directly bind to NAMPT (nicotinamide phosphoribosyltransferase) to promote its activity and maintain the NAD(P)H/NAD(P)+ homeostasis. These functions are necessary to the anti-stress ability of cells but independent of the dehydrogenase activity of G6PD. In addition, the wild type G6PD and naturally inactive mutant also can similarly regulate the metabolism of glucose, glutamine, fatty acid synthesis, and glutathione, and interact with the involved enzymes. Therefore, our findings reveal the previously unidentified functions of G6PD that can act as the important physiological neutralizer of stresses independently of its enzymatic activity.

Keywords:  G6PD; NADH homeostasis; NAMPT; oxidative stress; pentose phosphate pathway

DOI:  https://doi.org/10.1016/j.jbc.2022.102587
Mol Med. 2022 Oct 20. 28(1): 124

AAV-ie-mediated UCP2 overexpression accelerates inner hair cell loss during aging in vivo.

Chunli Zhao, Zijing Yang, Zhongrui Chen, Wenqi Liang, Shusheng Gong, Zhengde Du.

   BACKGROUND: Uncoupling protein 2 (UCP2), activated by excessive reactive oxygen species (ROS) in vivo, has the dual effect of reducing ROS to protect against oxidative stress and reducing ATP production to regulate cellular metabolism. Both the UCP2 and ROS are increased in cochleae in age-related hearing loss (ARHL). However, the role of UCP2 in sensory hair cells in ARHL remains unclear.
METHODS: Male C57BL/6 J mice were randomly assigned to an 8-week-old group (Group 1), a 16-week-old group (Group 2), a 16-week-old + adeno-associated virus-inner ear (AAV-ie) group (Group 3), and a 16-week-old + AAV-ie-UCP2 group (Group 4). Mice aged 8 weeks were administrated with AAV-ie-GFP or AAV-ie-UCP2 via posterior semicircular canal injection. Eight weeks after this viral intervention, hearing thresholds and wave-I amplitudes were tested by auditory brainstem response (ABR). Subsequently, the cochlear basilar membrane was dissected for investigation. The number of hair cells and inner hair cell (IHC) synapses, the level of ROS, and the expression of AMP-activated protein kinase α (AMPKα), were assessed by immunofluorescence staining. In addition, mitochondrial function was determined, and the expression of AMPKα and UCP2 proteins was further evaluated using western blotting.
RESULTS: Mice with early-onset ARHL exhibited enhanced oxidative stress and loss of outer hair cells and IHC synapses, while UCP2 overexpression aggravated hearing loss and cochlear pathophysiological changes in mice. UCP2 overexpression resulted in a notable decrease in the number of IHCs and IHC synapses, caused ATP depletion and excessive ROS generation, increased AMPKα protein levels, and promoted IHC apoptosis, especially in the apical and middle turns of the cochlea.
CONCLUSION: Collectively, our data suggest that UCP2 overexpression may cause mitochondrial dysfunction via energy metabolism, which activates mitochondrion-dependent cellular apoptosis and leads to IHC loss, ultimately exacerbating ARHL.

Keywords:  AMPKα; ARHL; Apoptosis; IHC; Mitochondrion; UCP2

DOI:  https://doi.org/10.1186/s10020-022-00552-y