bims-amsmem 2023-07-16 papers

bims-amsmem

Biomed News

on AMPK signaling mechanism in energy metabolism

Issue of 2023–07–16
eleven papers selected by
Dipsikha Biswas, Københavns Universitet

AMPK activation improves recovery from pneumonia-induced lung injury via reduction of er-stress and apoptosis in alveolar epithelial cells.
Metformin preconditioning protects against myocardial stunning and preserves protein translation in a mouse model of cardiac arrest.
AMPK boosts ADAM10 shedding activity in human aortic endothelial cells by promoting Rab14-dependent ADAM10 cell surface translocation.
LKB1 signaling is altered in skeletal muscle of a Duchenne muscular dystrophy mouse model.
Exogenous galanin alleviates hepatic steatosis by promoting autophagy via the AMPK-mTOR pathway.
Numerous Trigger-like Interactions of Kinases/Protein Phosphatases in Human Skeletal Muscles Can Underlie Transient Processes in Activation of Signaling Pathways during Exercise.
Targeting AMPK/eNOS pathway and mitochondria by sonlicromanol protects myocardial cells against ischemia-reperfusion injury.
AMPK/mTOR pathway significance in healthy liver and non-alcoholic fatty liver disease and its progression.
TIMELESS promotes the proliferation and migration of lung adenocarcinoma cells by activating EGFR through AMPK and SPHK1 regulation.
NPFR regulates the synthesis and metabolism of lipids and glycogen via AMPK: Novel targets for efficient corn borer management.
Quercetin ameliorates non-alcoholic fatty liver disease (NAFLD) via the promotion of AMPK-mediated hepatic mitophagy.

Respir Res. 2023 Jul 12. 24(1): 185

AMPK activation improves recovery from pneumonia-induced lung injury via reduction of er-stress and apoptosis in alveolar epithelial cells.

Eugene Becker, Maroof Husain, Nathaniel Bone, Samuel Smith, Peter Morris, Jaroslaw W Zmijewski.

   BACKGROUND: Bacterial pneumonia and related lung injury are among the most frequent causes of mortality in intensive care units, but also inflict serious and prolonged respiratory complications among survivors. Given that endoplasmic reticulum (ER) stress is a hallmark of sepsis-related alveolar epithelial cell (AEC) dysfunction, we tested if AMP-activated protein kinase (AMPK) affects recovery from ER stress and apoptosis of AECs during post-bacterial infection.
METHODS: In a murine model of lung injury by P. aeruginosa non-lethal infection, therapeutic interventions included AMPK activator metformin or GSK-3β inhibitor Tideglusib for 96 h. Recovery from AEC injury was evidenced by accumulation of soluble T-1α (AEC Type 1 marker) in BAL fluids along with fluorescence analysis of ER-stress (CHOP) and apoptosis (TUNEL) in lung sections. AMPK phosphorylation status and mediators of ER stress were determined via Immunoblot analysis from lung homogenates. Macrophage-dependent clearance of apoptotic cells was determined using flow cytometry assay.
RESULTS: P. aeruginosa-induced lung injury resulted in accumulation of neutrophils and cellular debris in the alveolar space along with persistent (96 h) ER-stress and apoptosis of AECs. While lung infection triggered AMPK inactivation (de-phosphorylation of Thr172-AMPK), metformin and Tideglusib promptly restored the AMPK activation status. In post infected mice, AMPK activation reduced indices of lung injury, ER stress and related apoptosis of AECs, as early as 24 h post administration of AMPK activators. In addition, we demonstrate that the extent of apoptotic cell accumulation is also dependent on AMPK-mediated clearance of apoptotic cells by macrophages.
CONCLUSIONS: Our study provides important insights into AMPK function in the preservation of AEC viability after bacterial infection, in particular due reduction of ER-stress and apoptosis, thereby promoting effective recovery from lung injury after pneumonia.

Keywords:  Alveolar epithelial cells; Bacterial infections; Efferocytosis; Endoplasmic reticulum; Mitochondria; Pneumonia

DOI:  https://doi.org/10.1186/s12931-023-02483-6
J Mol Cell Cardiol Plus. 2023 Jun;pii: 100034. [Epub ahead of print]4

Metformin preconditioning protects against myocardial stunning and preserves protein translation in a mouse model of cardiac arrest.

Cody A Rutledge, Claudia Lagranha, Takuto Chiba, Kevin Redding, Donna B Stolz, Eric Goetzman, Sunder Sims-Lucas, Brett A Kaufman.

  Cardiac arrest (CA) causes high mortality due to multi-system organ damage attributable to ischemia-reperfusion injury. Recent work in our group found that among diabetic patients who experienced cardiac arrest, those taking metformin had less evidence of cardiac and renal damage after cardiac arrest when compared to those not taking metformin. Based on these observations, we hypothesized that metformin's protective effects in the heart were mediated by AMPK signaling, and that AMPK signaling could be targeted as a therapeutic strategy following resuscitation from CA. The current study investigates metformin interventions on cardiac and renal outcomes in a non-diabetic CA mouse model. We found that two weeks of metformin pretreatment protects against reduced ejection fraction and reduces kidney ischemia-reperfusion injury at 24 h post-arrest. This cardiac and renal protection depends on AMPK signaling, as demonstrated by outcomes in mice pretreated with the AMPK activator AICAR or metformin plus the AMPK inhibitor compound C. At this 24-h time point, heart gene expression analysis showed that metformin pretreatment caused changes supporting autophagy, antioxidant response, and protein translation. Further investigation found associated improvements in mitochondrial structure and markers of autophagy. Notably, Western analysis indicated that protein synthesis was preserved in arrest hearts of animals pretreated with metformin. The AMPK activation-mediated preservation of protein synthesis was also observed in a hypoxia/reoxygenation cell culture model. Despite the positive impacts of pretreatment in vivo and in vitro, metformin did not preserve ejection fraction when deployed at resuscitation. Taken together, we propose that metformin's in vivo cardiac preservation occurs through AMPK activation, requires adaptation before arrest, and is associated with preserved protein translation.

Keywords:  AMPK; Cardiac arrest; Metformin; Myocardial stunning

DOI:  https://doi.org/10.1016/j.jmccpl.2023.100034
Biochem Biophys Res Commun. 2023 Jul 06. pii: S0006-291X(23)00858-6. [Epub ahead of print]675 54-60

AMPK boosts ADAM10 shedding activity in human aortic endothelial cells by promoting Rab14-dependent ADAM10 cell surface translocation.

Chung Hee Baek, Hyosang Kim, Soo Young Moon, Won Seok Yang.

  A disintegrin and metalloprotease 10 (ADAM10) regulates the expression of cell surface receptors such as tumor necrosis factor receptor 1, toll-like receptor 4, and the receptor for advanced glycation end products (RAGE) by cleaving their extracellular regions. To function as a sheddase, ADAM10 should translocate from the intracellular compartments to the cell surface, but the translocation mechanism remains unclear. In this study, we explored the possible role of adenosine monophosphate-activated protein kinase (AMPK) in the induction of ADAM10 shedding activity. In cultured human aortic endothelial cells (HAECs), 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR), an AMPK activator, boosted ADAM10 cell surface translocation and ectodomain shedding of RAGE. ADAM10 inhibition with GI 254023X and ADAM10 siRNA silencing both prevented AICAR-induced RAGE ectodomain shedding. AICAR increased AMPK phosphorylation as well. Both Compound C-mediated AMPK inhibition and AMPKα1-siRNA-mediated AMPK depletion suppressed AICAR-induced ADAM10 cell surface translocation and RAGE ectodomain shedding. On the other hand, siRNA knockdown of Rab14, a small GTPase that facilitates the intracellular trafficking of transmembrane proteins, prevented AICAR-induced ADAM10 cell surface translocation and RAGE ectodomain shedding. In conclusion, AMPK activation is an obvious inducer of ADAM10 shedding activity. Our findings suggest that AMPK boosts ADAM10 shedding activity in HAECs by promoting Rab14-dependent ADAM10 cell surface translocation.

Keywords:  A disintegrin and metalloprotease 10; AMP-activated protein kinase; Cell surface trafficking; Rab14; Receptor for advanced glycation end products

DOI:  https://doi.org/10.1016/j.bbrc.2023.07.010
Dis Model Mech. 2023 Jul 01. pii: dmm049930. [Epub ahead of print]16(7):

LKB1 signaling is altered in skeletal muscle of a Duchenne muscular dystrophy mouse model.

Brigida Boccanegra, Paola Mantuano, Elena Conte, Alessandro Giovanni Cerchiara, Lisamaura Tulimiero, Raffaella Quarta, Erika Caputo, Francesca Sanarica, Monica Forino, Valeria Spadotto, Ornella Cappellari, Gianluca Fossati, Christian Steinkühler, Annamaria De Luca.

  The potential role of liver kinase B1 (LKB1) in the altered activation of the master metabolic and epigenetic regulator adenosine monophosphate-activated protein kinase (AMPK) in Duchenne muscular dystrophy has not been investigated so far. Hence, we analyzed both gene and protein levels of LKB1 and its related targets in gastrocnemius muscles of adult C57BL/10 mdx mice and D2 mdx mice, a model with a more severe dystrophic phenotype, as well as the sensitivity of the LKB1-AMPK pathway to AMPK activators, such as chronic exercise. Our data show, for the first time, a reduction in the levels of LKB1 and accessory proteins, MO25 and STRADα, in both mdx strains versus the respective wild type, which was further impaired by exercise, in parallel with a lack of further phosphorylation of AMPK. The AMPK-like kinase salt-inducible kinase (SIK) and class II histone deacetylases, along with expression of the HDAC target gene Mef2c, were also altered, supporting an impairment of LKB1-SIK-class II histone deacetylase signaling. Our results demonstrate that LKB1 may be involved in dystrophic progression, paving the way for future preclinical studies.

Keywords:  AMPK; Duchenne muscular dystrophy; Epigenetic; LKB1; Mouse models; Muscle metabolism

DOI:  https://doi.org/10.1242/dmm.049930
Arch Biochem Biophys. 2023 Jul 08. pii: S0003-9861(23)00188-1. [Epub ahead of print] 109689

Exogenous galanin alleviates hepatic steatosis by promoting autophagy via the AMPK-mTOR pathway.

Shuyuan Zhu, Shuai Wang, Tao Luo.

  Defective autophagy-induced intracellular lipid degradation is causally associated with non-alcoholic fatty liver disease (NAFLD) development. Therefore, agents that can restore autophagy may have potential clinical application prospects on this public health issue. Galanin (GAL) is a pleiotropic peptide that regulates autophagy and is a potential drug for the treatment of NAFLD. In this study, we used an MCD-induced NAFLD mouse model in vivo and an FFA-induced HepG2 hepatocyte model in vitro to evaluate the anti-NAFLD effect of GAL. Exogenous GAL supplementation significantly attenuated lipid droplet accumulation and suppressed hepatocyte TG levels in mice and cell models. Mechanistically, Galanin-mediated reduction of lipid accumulation was positively correlated with upregulated p-AMPK, as evidenced by upregulated protein expressions of fatty acid oxidation-related gene markers (PPAR-α and CPT1A), upregulated expressions of the autophagy-related marker (LC3B), and downregulated autophagic substrate p62 levels. In FFA-treated HepG2 cells, activation of fatty acid oxidation and autophagy-related proteins by galanin was reversed by autophagy inhibitors, chloroquine, and the AMPK inhibitor. Galanin ameliorates hepatic fat accumulation by inducing autophagy and fatty acid oxidation via the AMPK/mTOR pathway.

Keywords:  AMPK; Autophagy; Galanin; NAFLD; β-Oxidation

DOI:  https://doi.org/10.1016/j.abb.2023.109689
Int J Mol Sci. 2023 Jul 07. pii: 11223. [Epub ahead of print]24(13):

Numerous Trigger-like Interactions of Kinases/Protein Phosphatases in Human Skeletal Muscles Can Underlie Transient Processes in Activation of Signaling Pathways during Exercise.

Alexander Yu Vertyshev, Ilya R Akberdin, Fedor A Kolpakov.

  Optimizing physical training regimens to increase muscle aerobic capacity requires an understanding of the internal processes that occur during exercise that initiate subsequent adaptation. During exercise, muscle cells undergo a series of metabolic events that trigger downstream signaling pathways and induce the expression of many genes in working muscle fibers. There are a number of studies that show the dependence of changes in the activity of AMP-activated protein kinase (AMPK), one of the mediators of cellular signaling pathways, on the duration and intensity of single exercises. The activity of various AMPK isoforms can change in different directions, increasing for some isoforms and decreasing for others, depending on the intensity and duration of the load. This review summarizes research data on changes in the activity of AMPK, Ca2+/calmodulin-dependent protein kinase II (CaMKII), and other components of the signaling pathways in skeletal muscles during exercise. Based on these data, we hypothesize that the observed changes in AMPK activity may be largely related to metabolic and signaling transients rather than exercise intensity per se. Probably, the main events associated with these transients occur at the beginning of the exercise in a time window of about 1-10 min. We hypothesize that these transients may be partly due to putative trigger-like kinase/protein phosphatase interactions regulated by feedback loops. In addition, numerous dynamically changing factors, such as [Ca2+], metabolite concentration, and reactive oxygen and nitrogen species (RONS), can shift the switching thresholds and change the states of these triggers, thereby affecting the activity of kinases (in particular, AMPK and CaMKII) and phosphatases. The review considers the putative molecular mechanisms underlying trigger-like interactions. The proposed hypothesis allows for a reinterpretation of the experimental data available in the literature as well as the generation of ideas to optimize future training regimens.

Keywords:  AMPK signalling; Ca2+-dependent signalling; mathematical model; physical exercise; protein phosphatases; skeletal muscle; transient process

DOI:  https://doi.org/10.3390/ijms241311223
Gen Physiol Biophys. 2023 Jul;42(4): 373-382

Targeting AMPK/eNOS pathway and mitochondria by sonlicromanol protects myocardial cells against ischemia-reperfusion injury.

Kun Liao, Fangfei Huang, Xing Xie, Linhui Li.

This work evaluated the cardioprotective effects of sonlicromanol, a new mitochondrial-directed drug, on cardiac ischemia/reperfusion (I/R) injury and explored the involvement of inflammatory and oxidative responses via activation of AMPK-eNOS-mitochondrial pathway. Male Sprague-Dawley rats underwent regional I/R injury through in vivo left anterior descending (LAD) coronary artery ligation for 40 minutes followed by 24 hours of reperfusion. Pretreatment of rats with sonlicromanol considerably reduced cardiac I/R injury in a dose-dependent manner, as indicated by lower infarct size and serum creatine-kinase levels, and improved cardiac function after reperfusion. Sonlicromanol (50 mg/kg) significantly reduced TNF-α, interleukin-1β, NF-κB-p65, and 8-isoprostane levels while increased manganese-superoxide dismutase and nitric-oxide levels and expression of eNOS and AMPK protein. It significantly reduced mitochondrial membrane depolarization and reactive oxygen species (ROS) levels. However, AMPK inhibition significantly reduced sonlicromanol protective actions. Cardioprotection by sonlicromanol was achieved by moderating inflammatory and oxidative responses, and AMPK/eNOS/mitochondrial signaling is a crucial regulator of these actions.

DOI: https://doi.org/10.4149/gpb_2023003
J Gastroenterol Hepatol. 2023 Jul 12.

AMPK/mTOR pathway significance in healthy liver and non-alcoholic fatty liver disease and its progression.

Ilitch Aquino Marcondes-de-Castro, Pedro Henrique Reis-Barbosa, Thatiany Souza Marinho, Marcia Barbosa Aguila, Carlos Alberto Mandarim-de-Lacerda.

  Obesity is related to several organs, but the liver is particularly affected. Adenosine monophosphate-activated protein kinase (AMPK) is a cellular energy sensor and regulator of liver lipid dysfunction and glucose metabolism. The mechanistic target of rapamycin (mTOR) is a protein kinase regulating cell growth, survival, metabolism, and immunity. Together, these pathways are involved in obesity, insulin resistance, non-alcoholic fatty liver disease (NAFLD) and its progression, and autophagy. During energy demand, liver kinase B (LKB) phosphorylation helps activate the AMPK/mTOR pathways. Likewise, the protein forkhead box O family (FOXO) negatively regulates adipogenesis by binding to the promoter sites of peroxisome proliferator-activated receptor-gamma coactivator 1-alpha, initiating adipogenesis. In addition, acetyl-CoA carboxylase, which regulates de novo lipogenesis, is linked to LKB and FOXO in developing NAFLD. The kinase complex, consisting of Unc-51-like autophagy-activating kinase 1 or 2 (ULK1, ULK2) by stimulating autophagy, and eliminating fat droplets in NAFLD, is regulated by mTORC1 and negatively regulated by AMPK that suppresses liver lipogenesis and increases fatty acid oxidation. Also, ULK1 is essential for initiating phagophore formation, establishing macrophagy, and generating autophagosomes. The selective breakdown of lipid droplets through macroautophagy, or macrolipophagy, occurs on a cellular energy level using free fatty acids. In addition, mTORC1 promotes lipogenesis by activating sterol regulatory element-binding protein. Finding new components and novel regulatory modes in signaling is significant for a better understanding of the AMPK/mTOR pathways, potentially facilitating the development of future diagnostic and therapeutic strategies for NAFLD and its progression to non-alcoholic steatohepatitis, cirrhosis, and hepatocellular carcinoma.

Keywords:  AMPK/mTOR pathway; autophagy; lipid metabolism; non-alcoholic fatty liver disease; obesity

DOI:  https://doi.org/10.1111/jgh.16272
Eur J Pharmacol. 2023 Jul 09. pii: S0014-2999(23)00394-1. [Epub ahead of print] 175883

TIMELESS promotes the proliferation and migration of lung adenocarcinoma cells by activating EGFR through AMPK and SPHK1 regulation.

Houqing Yin, Zequn Wang, Dan Wang, Muhadaisi Nuer, Mengyuan Han, Peng Ren, Shanwu Ma, Chutong Lin, Jingjing Chen, Haocheng Xian, Dongmei Ai, Xuejun Li, Shaohua Ma, Zhiqiang Lin, Yan Pan.

   BACKGROUND: Lung adenocarcinoma (LUAD) has high morbidity and is prone to recurrence. TIMELESS (TIM), which regulates circadian rhythms in Drosophila, is highly expressed in various tumors. Its role in LUAD has gained attention, but the detailed function and mechanism have not been clarified completely at present.
METHODS: Tumor samples from patients with LUAD patient data from public databases were used to confirm the relationship of TIM expression with lung cancer. LUAD cell lines were used and siRNA of TIM was adopted to knock down TIM expression in LUAD cells, and further cell proliferation, migration and colony formation were analyzed. By using Western blot and qPCR, we detected the influence of TIM on epidermal growth factor receptor (EGFR), sphingosine kinase 1 (SPHK1) and AMP-activated protein kinase (AMPK). With proteomics analysis, we comprehensively inspected the different changed proteins influenced by TIM and did global bioinformatic analysis.
RESULTS: We found that TIM expression was elevated in LUAD and that this high expression was positively correlated with more advanced tumor pathological stages and shorter overall and disease-free survival. TIM knockdown inhibited EGFR activation and also AKT/mTOR phosphorylation. We also clarified that TIM regulated the activation of SPHK1 in LUAD cells. And with SPHK1 siRNA to knock down the expression level of SPHK1, we found that EGFR activation were inhibited greatly too. Quantitative proteomics techniques combined with bioinformatics analysis clarified the global molecular mechanisms regulated by TIM in LUAD. The results of proteomics suggested that mitochondrial translation elongation and termination were altered, which were closely related to the process of mitochondrial oxidative phosphorylation. We further confirmed that TIM knockdown reduced ATP content and promoted AMPK activation in LUAD cells.
CONCLUSIONS: Our study revealed that siTIM could inhibited EGFR activation through activating AMPK and inhibiting SPHK1 expression, as well as influencing mitochondrial function and alter the ATP level; TIM's high expression in LUAD is an important factor and a potential key target in LUAD.

Keywords:  AMP-activated protein kinase; Epidermal growth factor receptor; Lung adenocarcinoma; Sphingosine kinase 1; TIMELESS

DOI:  https://doi.org/10.1016/j.ejphar.2023.175883
Int J Biol Macromol. 2023 Jul 12. pii: S0141-8130(23)02711-3. [Epub ahead of print] 125816

NPFR regulates the synthesis and metabolism of lipids and glycogen via AMPK: Novel targets for efficient corn borer management.

Jiajia Zhao, Shuo Yan, Mingshan Li, Lina Sun, Min Dong, Meizhen Yin, Jie Shen, Zhangwu Zhao.

  RNA biopesticides are regarded as "the third revolution in the history of pesticides" due to their extensive advantages such as precision, high efficiency, green, pollution-free, etc. In the current study, two target genes encoding neuropeptide F receptor (NPFR) and AMP-activated protein kinase (AMPK), which are essential for insect feeding, cellular energy homeostasis and nutrient availability, were selected to design RNA pesticides. We achieved high RNA interference (RNAi) efficiency of npfr via a star polycation nanocarrier-based double-stranded RNA (dsRNA) delivery system. The food consumption of Ostrinia furnacalis is largely suppressed, which leads to a good protective effect on corn leaves. We determined the mechanism of the above genes. NPFR binds to the Gα protein and activates the intracellular second messengers cAMP and Ca2+, which in turn phosphorylate AMPK to regulate the synthesis and metabolism of lipids and glycogen. We then adopted a highly efficient bacteria-based expression system for the production of large amounts of dsRNA segments targeting npfr and ampk simultaneously and subsequently complexed them with nanocarriers to develop a novel dual-target RNA pesticide. Our RNA nanopesticide dramatically inhibits larval feeding, growth and development, and its controlling effect is even better than that of the widely used anti-feedant azadirachtin.

Keywords:  Nanocarrier; RNA biopesticides; RNA interference

DOI:  https://doi.org/10.1016/j.ijbiomac.2023.125816
J Nutr Biochem. 2023 Jul 07. pii: S0955-2863(23)00147-X. [Epub ahead of print] 109414

Quercetin ameliorates non-alcoholic fatty liver disease (NAFLD) via the promotion of AMPK-mediated hepatic mitophagy.

Peng Cao, Yi Wang, Cong Zhang, Mitchell A Sullivan, Wen Chen, Xiang Jing, Huifan Yu, Fei Li, Qu Wang, Zhongshi Zhou, Qi Wang, Wen Tian, Zhenpeng Qiu, Lianxiang Luo.

   BACKGROUND: The global incidence of non-alcoholic fatty liver disease (NAFLD) has been surging in recent years, however, no drug is currently approved to treat this disease.
PURPOSE: Quercetin, a natural flavonoid abundant in plants and fruits, has been reported to alleviate NAFLD, however, the exact molecular mechanism remains unclear. This study aims to further elucidate its potential mechanism of action.
METHODS: The beneficial effects and the underlying mechanism of quercetin in alleviating NAFLD were explored both in vitro and in vivo, by employing chemical inhibitors of autophagosomes (3-methyladenine, 3-MA), autolysosomes (chloroquine, CQ), AMPK (Compound C, CC) and SIRT1 (selisistat, EX-527). The levels of intracellular lipids, reactive oxygen species, mitochondria function, autophagy and mitophagy were assessed by fluorescent labeling and examined using flow cytometry or confocal microscopy. Key protein expressions of autophagy, mitophagy and inflammation were also determined.
RESULTS: In vivo, quercetin was shown to dose-dependently effectively alleviate NAFLD, but intraperitoneal injection of 3-MA could block the beneficial effects of quercetin on body weight, liver weight, serum ALT/AST, hepatic ROS and inflammation. In vitro, quercetin could reduce intracellular lipids (Nile Red staining) and ROS/DHE accumulation, which could be also blocked by 3-MA or CQ. Furthermore, we found that CC could abrogate the protective effects of quercetin on lipid and ROS accumulation in vitro. Also, CC abolished the pro-autophagic and anti-inflammatory effects of quercetin, as shown by western blot determination and Lyso-Tracker labeling. Importantly, mitophagy, a specific form of mitochondria-targeted autophagy, was enhanced by quercetin, as demonstrated by PINK1/Parkin protein variation and immunofluorescence co-localization of autophagosomes and mitochondria, which could also be blocked by the intervention of CC.
CONCLUSIONS: This study demonstrates that quercetin prevents NAFLD through AMPK-mediated mitophagy and suggests that promoting mitophagy via an upregulation of AMPK may be a promising therapeutic strategy against NAFLD.

Keywords:  AMPK; NAFLD; autophagy; mitophagy; quercetin

DOI:  https://doi.org/10.1016/j.jnutbio.2023.109414