bims-amsmem 2022-09-18 papers

bims-amsmem

Biomed News

on AMPK signaling mechanism in energy metabolism

Issue of 2022–09–18
twenty papers selected by
Dipsikha Biswas, Københavns Universitet

AMPK and Diseases: State of the Art Regulation by AMPK-Targeting Molecules.
Lin28A alleviates ovariectomy-induced osteoporosis through activation of the AMP-activated protein kinase pathway in rats.
Metformin suppresses proliferation and differentiation induced by BMP9 via AMPK signaling in human fetal lung fibroblast-1.
ER stress induces myocardial dysfunction and cardiac autophagy in Sestrin2 knockout mice.
Shared pathobiology identifies AMPK as a therapeutic target for obesity and autosomal dominant polycystic kidney disease.
Modulation of hypothalamic AMPK and hypothalamic neuropeptides in the control of eating behavior: A systematic review.
AMP-activated protein kinase α2 contributes to acute and chronic hyperuricemic nephropathy via renal urate deposition in a mouse model.
Metabolomics reveals mouse plasma metabolite responses to acute exercise and effects of disrupting AMPK-glycogen interactions.
Activation of AMPK/p38/Nrf2 is involved in resveratrol alleviating myocardial ischemia-reperfusion injury in diabetic rats as an endogenous antioxidant stress feedback.
Estrogen-related receptor alpha is an AMPK-regulated factor that promotes ischemic muscle revascularization and recovery in diet-induced obese mice.
Sodium selenite inhibits cervical cancer growth via ROS mediated AMPK/FOXO3a /GADD45a axis.
Skeletal muscle contraction kinetics and AMPK responses are modulated by the adenine nucleotide degrading enzyme AMPD1.
cAMP-Protein Kinase A and Stress-Activated MAP Kinase signaling mediate transcriptional control of autophagy in fission yeast during glucose limitation or starvation.
Sensing local energetics to acutely regulate mitophagy in skeletal muscle.
MCM7 supports the stemness of bladder cancer stem-like cells by enhancing autophagic flux.
Co-Treatment With Resveratrol and FGF1 Protects Against Acute Liver Toxicity After Doxorubicin Treatment via the AMPK/NRF2 Pathway.
An AMPK phosphoregulated RhoGEF feedback loop tunes cortical flow-driven amoeboid migration in vivo.
Ginsenoside Rg1 Ameliorates Acute Renal Ischemia/Reperfusion Injury via Upregulating AMPKα1 Expression.
Zhuanggu Zhitong Capsule alleviates postmenopausal osteoporosis in ovariectomized rats by regulating autophagy through AMPK/mTOR signaling pathway.
NANOG regulates epithelial-mesenchymal transition via AMPK/mTOR signalling pathway in ovarian cancer SKOV-3 and A2780 cells.

Biology (Basel). 2022 Jul 11. pii: 1041. [Epub ahead of print]11(7):

AMPK and Diseases: State of the Art Regulation by AMPK-Targeting Molecules.

Olga Tarasiuk, Matteo Miceli, Alessandro Di Domizio, Gabriella Nicolini.

  5'-adenosine monophosphate (AMP)-activated protein kinase (AMPK) is an enzyme that regulates cellular energy homeostasis, glucose, fatty acid uptake, and oxidation at low cellular ATP levels. AMPK plays an important role in several molecular mechanisms and physiological conditions. It has been shown that AMPK can be dysregulated in different chronic diseases, such as inflammation, diabetes, obesity, and cancer. Due to its fundamental role in physiological and pathological cellular processes, AMPK is considered one of the most important targets for treating different diseases. Over decades, different AMPK targeting compounds have been discovered, starting from those that activate AMPK indirectly by altering intracellular AMP:ATP ratio to compounds that activate AMPK directly by binding to its activation sites. However, indirect altering of intracellular AMP:ATP ratio influences different cellular processes and induces side effects. Direct AMPK activators showed more promising results in eliminating side effects as well as the possibility to engineer drugs for specific AMPK isoforms activation. In this review, we discuss AMPK targeting drugs, especially concentrating on those compounds that activate AMPK by mimicking AMP. These compounds are poorly described in the literature and still, a lot of questions remain unanswered about the exact mechanism of AMP regulation. Future investigation of the mechanism of AMP binding will make it possible to develop new compounds that, in combination with others, can activate AMPK in a synergistic manner.

Keywords:  ADaM site; AMP; AMP mimicking; AMPK regulation; direct and indirect AMPK activators

DOI:  https://doi.org/10.3390/biology11071041
Int J Rheum Dis. 2022 Sep 15.

Lin28A alleviates ovariectomy-induced osteoporosis through activation of the AMP-activated protein kinase pathway in rats.

Liang Cai, Zhanwang Gao, Zhiping Gu.

   AIM: To investigate the role of Lin28A in ovariectomy-induced osteoporosis and to elucidate the underlying molecular mechanism.
METHODS: Bilateral ovariectomy was conducted to generate an ovariectomy (OVX) rat model. Western blotting was performed to assess the relative expression levels of Lin28A, osteocalcin (OCN), runt-related transcription factor 2 (RUNX2), adenosine monophosphate-activated protein kinase (AMPK) and phosphorylated AMPK (p-AMPK) proteins. Enzyme-linked immunosorbent assays were performed to detect the serum levels of calcium, E2, alkaline phosphatase (ALP) and interleukin (IL)-1β. Three-point bending test was used to assess biomechanical parameters of left femoral diaphysis. Hematoxylin and eosin (HE) staining was conducted to detect the trabecular structure of bone tissue. Dihydroethidium assay kit was used to measure the intracellular reactive oxygen species (ROS) level in osteoclasts. Alizarin red staining revealed the calcium deposit in bone marrow stromal cells (BMSC).
RESULTS: The expression levels of Lin28A, OCN, RUNX2, AMPK and p-AMPK proteins were significantly decreased in OVX rats. The serum levels of calcium, E2, ALP and IL-1β were significantly declined in OVX rats. Biomechanical parameters of left femoral diaphysis were significantly decreased in OVX rats. OVX-induced trabecular abnormalities. ROS level was dramatically increased in the bone tissue of OVX rats, and calcium deposit was dramatically decreased in BMSC cells of OVX rats. These effects induced by OVX could be prevented by overexpression of Lin28A.
CONCLUSION: Lin28A alleviates ovariectomy-induced osteoporosis through activation of AMPK pathway in rats.

Keywords:  AMPK pathway; Lin28A; osteoporosis; ovariectomy

DOI:  https://doi.org/10.1111/1756-185X.14436
Front Pharmacol. 2022 ;13 984730

Metformin suppresses proliferation and differentiation induced by BMP9 via AMPK signaling in human fetal lung fibroblast-1.

Qiongfeng Chen, Yaqun Wang, Linna Sheng, Yonghong Huang.

  Adenosine monophosphosphate-activated protein kinase (AMPK) and its activator metformin were found to be involved in the regulation of fibroblast activation and pulmonary fibrosis. However, the regulatory mechanism has been undetermined. Recently, AMPK has been reported to exert its effect through inhibiting bone morphogenetic protein (BMP) pathway. In this study, human fetal lung fibroblast (HFL-1) cells were treated with metformin or specific AMPKα1 mutants, including constitutively activated mutant (AMPK-CA) and dominant negative mutant (AMPK-DN), combined with BMP9, and then the absorbance of these cells was measured by cell counting kit (CCK)-8 assay. The colony number of HFL-1 cells stimulated by metformin with or without BMP9 was examined by colony formation assay. The protein expressions of differentiated markers (α-smooth muscle actin, collagen I and collagen III) and the key molecules of BMP9 signaling, including activin receptor-like kinase (ALK) one and phosphorylated small mother against decapentaplegic (p-Smad)1/5, were also evaluated by western blot. Data revealed that BMP9 induced the proliferation and differentiation of HFL-1 cells which was suppressed by metformin or AMPK-CA. Meanwhile, the effect of metformin on BMP9-induced activation was counteracted by AMPK-DN. In addition, we found that the expressions of ALK1 and p-Smad1/5 induced by BMP9 were attenuated by metformin and AMPK-CA, whereas the inhibitory responses of metformin to the increased ALK1 and p-Smad1/5 were reduced by AMPK-DN. Accordingly, these results suggested that metformin mitigated BMP9-induced proliferation and differentiation of HFL-1 cells, which was achieved partly through the activation of AMPK and inhibition of ALK1/Smad1/5 signaling.

Keywords:  AMPK; BMP9; differentiation; lung fibroblast; metformin; proliferation

DOI:  https://doi.org/10.3389/fphar.2022.984730
Am J Transl Res. 2022 ;14(8): 5800-5811

ER stress induces myocardial dysfunction and cardiac autophagy in Sestrin2 knockout mice.

Jie Zhang, Linlin Yao, Shaohua Li, Misbahul Ferdous, Peng Zhao.

OBJECTIVES: Sestrin2 is an essential regulator of the cellular adaptive response against various stresses. The endoplasmic reticulum (ER) is critical in maintaining normal cardiac function by controlling intracellular Ca2+ accumulation, as well as protein folding and processing. Autophagy contributes to stress-associated heart dysfunction. AMP-activated protein kinase (AMPK) is important in energy homeostasis in cardiomyocytes. However, the function of Sestrin2 (Sesn2) in ER stress-induced autophagy that induces myocardial dysfunction has not been clarified. In this study, mice and cardiac tissues were treated with tunicamycin (TN), an inducer of ER stress. We then explored the roles of Sesn2 and the AMPK pathway associated with autophagy in ER stress-induced myocardial dysfunction in mice.
METHODS: Echocardiography, contractile function analysis, intracellular Ca2+ status, and immunoblot analysis of AMPK pathway were performed, ER stress and autophagy markers were examined.
RESULTS: The study revealed that ER stress caused significant heart dysfunction and cardiotoxicity in the mouse heart and cardiomyocytes. Biochemical analysis indicated enhanced cardiac autophagy mediated by ER stress and AMPK/mTOR activation. Sesn2 knockout exacerbated ER stress-related myocardial dysfunction due to the failed response of cardiac autophagy and AMPK/mTOR pathway activation. Further, pharmacological inhibition of AMPK or autophagy worsened TN-induced cardiac dysfunction.
CONCLUSION: Taken together, loss of the Sesn2 protein exacerbates ER stress-induced cardiac dysfunction through the AMPK/mTOR signaling cascade and loss of autophagy response.

Keywords: ER stress; Sestrin2; autophagy; cardiac dysfunction
Front Mol Biosci. 2022 ;9 962933

Shared pathobiology identifies AMPK as a therapeutic target for obesity and autosomal dominant polycystic kidney disease.

Ioan-Andrei Iliuta, Xuewen Song, Lauren Pickel, Amirreza Haghighi, Ravi Retnakaran, James Scholey, Hoon-Ki Sung, Gregory R Steinberg, York Pei.

  Autosomal dominant polycystic kidney disease (ADPKD) is the most common Mendelian kidney disease, affecting approximately one in 1,000 births and accounting for 5% of end-stage kidney disease in developed countries. The pathophysiology of ADPKD is strongly linked to metabolic dysregulation, which may be secondary to defective polycystin function. Overweight and obesity are highly prevalent in patients with ADPKD and constitute an independent risk factor for progression. Recent studies have highlighted reduced AMP-activated protein kinase (AMPK) activity, increased mammalian target of rapamycin (mTOR) signaling, and mitochondrial dysfunction as shared pathobiology between ADPKD and overweight/obesity. Notably, mTOR and AMPK are two diametrically opposed sensors of energy metabolism that regulate cell growth and proliferation. However, treatment with the current generation of mTOR inhibitors is poorly tolerated due to their toxicity, making clinical translation difficult. By contrast, multiple preclinical and clinical studies have shown that pharmacological activation of AMPK provides a promising approach to treat ADPKD. In this narrative review, we summarize the pleiotropic functions of AMPK as a regulator of cellular proliferation, macromolecule metabolism, and mitochondrial biogenesis, and discuss the potential for pharmacological activation of AMPK to treat ADPKD and obesity-related kidney disease.

Keywords:  AMPK; autosomal dominant polycystic kidney disease; energy metabolism; metabolic dysregulation; obesity

DOI:  https://doi.org/10.3389/fmolb.2022.962933
Life Sci. 2022 Sep 09. pii: S0024-3205(22)00647-6. [Epub ahead of print] 120947

Modulation of hypothalamic AMPK and hypothalamic neuropeptides in the control of eating behavior: A systematic review.

Letycia Dos Santos Neves, Renata Kelly Gomes Oliveira, Lucimeire Santana Dos Santos, Ingrid Oliveira Ribeiro, Jairza Maria Barreto Medeiros, Rhowena Jane Barbosa de Matos.

  Eating behavior is regulated by central and peripheral signals, which interact to modulate the response to nutrient intake. Central control is mediated by the hypothalamus through neuropeptides that activate the orexigenic and anorexigenic pathways. Energy homeostasis depends on the efficiency of these regulatory mechanisms. This neuroendocrine regulation of hunger and appetite can be modulated by nutritional sensors such as adenosine monophosphate-activated protein kinase (AMPK). Thus, this systematic review discusses the literature on correlations between AMPK and hypothalamic neuropeptides regarding control of eating behavior. Lilacs, PubMed/Medline, ScienceDirect, and Web of Science were searched for articles published from 2009 to 2021 containing combinations of the following descriptors: "eating behavior," "hypothalamus," "neuropeptide," and "AMPK." Of the 1330 articles found initially, 27 were selected after application of the inclusion and exclusion criteria. Of the selected articles, 15 reported decreased AMPK activity, due to interventions using angiotensin II infusion, fructose, glucose, cholecystokinin, leptin, or lipopolysaccharide (LPS) injection; dietary control through a low-protein diet or a high-fat diet (60 % fat); induction of hyperthyroidism; or injection of AMPK inhibitors. Seven studies showed a decrease in neuropeptide Y (NPY) through CV4 AICAR administration; fructose, glucose, leptin, or angiotensin II injections; or infusion of LPS from Escherichia coli and liver kinase B1 (LKB1) overexpression. Eleven studies reported a decrease in food consumption due to a decrease in AMPK activity and/or hypothalamic neuropeptides such as NPY. The results indicate that there is a relationship between AMPK and the control of eating behavior: a decrease in AMPK activity due to a dietary or non-dietary stimulus is associated with a consequent decrease in food intake. Furthermore, AMPK activity can be modulated by glucose, thyroid hormones, estradiol, leptin, and ghrelin.

Keywords:  AMPK; Eating behavior; Hypothalamus; Neuropeptides

DOI:  https://doi.org/10.1016/j.lfs.2022.120947
Eur J Med Res. 2022 Sep 10. 27(1): 176

AMP-activated protein kinase α2 contributes to acute and chronic hyperuricemic nephropathy via renal urate deposition in a mouse model.

Chen Yang, Hong-Yong Su, Ning An, Hong-Luan Wu, Xiao-Yan Guo, Zhi-Hang Li, Xiao-Cui Chen, Shao-Ping Zhu, Dan Wu, Hui-Yuan Li, Qing-Jun Pan, Dong Liang, Hua-Feng Liu.

  Hyperuricemia can induce acute and chronic kidney damage, but the pathological mechanism remains unclear. The potential role of AMP-activated protein kinase (AMPK) α2 in hyperuricemia-induced renal injury was investigated in this study. Acute and chronic hyperuricemic nephropathy was induced by administering intraperitoneal injections of uric acid and oxonic acid to AMPK α2 knockout and wild-type mice. Changes in renal function, histopathology, inflammatory cell infiltration, renal interstitial fibrosis, and urate deposition were analyzed. In both acute and chronic hyperuricemic nephropathy mouse models, knockout of AMPK α2 significantly reduced serum creatinine levels and renal pathological changes. The tubular expression of kidney injury molecule-1 was also reduced in hyperuricemic nephropathy mice deficient in AMPK α2. In addition, knockout of AMPK α2 significantly suppressed the infiltration of renal macrophages and progression of renal interstitial fibrosis in mice with chronic hyperuricemic nephropathy. Knockout of AMPK α2 reduced renal urate crystal deposition, probably through increasing the expression of the uric acid transporter, multidrug resistance protein 4. In summary, AMPK α2 is involved in acute and chronic hyperuricemia-induced kidney injury and may be associated with increased urate crystal deposition in the kidney.

Keywords:  AMPK α2; Hyperuricemia; Renal fibrosis; Renal inflammation; Urate deposition

DOI:  https://doi.org/10.1186/s40001-022-00800-1
Front Mol Biosci. 2022 ;9 957549

Metabolomics reveals mouse plasma metabolite responses to acute exercise and effects of disrupting AMPK-glycogen interactions.

Mehdi R Belhaj, Nathan G Lawler, John A Hawley, David I Broadhurst, Nolan J Hoffman, Stacey N Reinke.

  Introduction: The AMP-activated protein kinase (AMPK) is a master regulator of energy homeostasis that becomes activated by exercise and binds glycogen, an important energy store required to meet exercise-induced energy demands. Disruption of AMPK-glycogen interactions in mice reduces exercise capacity and impairs whole-body metabolism. However, the mechanisms underlying these phenotypic effects at rest and following exercise are unknown. Furthermore, the plasma metabolite responses to an acute exercise challenge in mice remain largely uncharacterized. Methods: Plasma samples were collected from wild type (WT) and AMPK double knock-in (DKI) mice with disrupted AMPK-glycogen binding at rest and following 30-min submaximal treadmill running. An untargeted metabolomics approach was utilized to determine the breadth of plasma metabolite changes occurring in response to acute exercise and the effects of disrupting AMPK-glycogen binding. Results: Relative to WT mice, DKI mice had reduced maximal running speed (p < 0.0001) concomitant with increased body mass (p < 0.01) and adiposity (p < 0.001). A total of 83 plasma metabolites were identified/annotated, with 17 metabolites significantly different (p < 0.05; FDR<0.1) in exercised (↑6; ↓11) versus rested mice, including amino acids, acylcarnitines and steroid hormones. Pantothenic acid was reduced in DKI mice versus WT. Distinct plasma metabolite profiles were observed between the rest and exercise conditions and between WT and DKI mice at rest, while metabolite profiles of both genotypes converged following exercise. These differences in metabolite profiles were primarily explained by exercise-associated increases in acylcarnitines and steroid hormones as well as decreases in amino acids and derivatives following exercise. DKI plasma showed greater decreases in amino acids following exercise versus WT. Conclusion: This is the first study to map mouse plasma metabolomic changes following a bout of acute exercise in WT mice and the effects of disrupting AMPK-glycogen interactions in DKI mice. Untargeted metabolomics revealed alterations in metabolite profiles between rested and exercised mice in both genotypes, and between genotypes at rest. This study has uncovered known and previously unreported plasma metabolite responses to acute exercise in WT mice, as well as greater decreases in amino acids following exercise in DKI plasma. Reduced pantothenic acid levels may contribute to differences in fuel utilization in DKI mice.

Keywords:  AMP-activated protein kinase; acylcarnitines; amino acids; exercise metabolism; glycogen; metabolomics; pantothenic acid; plasma metabolite

DOI:  https://doi.org/10.3389/fmolb.2022.957549
Ann Transl Med. 2022 Aug;10(16): 890

Activation of AMPK/p38/Nrf2 is involved in resveratrol alleviating myocardial ischemia-reperfusion injury in diabetic rats as an endogenous antioxidant stress feedback.

Guiping Xu, Yankai Ma, Jing Jin, Xiaoli Wang.

   Background: Myocardial necrosis caused by myocardial ischemia-reperfusion (MI/R) in diabetic patients is prominently aggravated and can cause oxidative stress. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a redox-sensing transcription factor that protects against myocardial ischemia/reperfusion injury (MIRI). However, the mechanism of action of Nrf2 in resveratrol-pretreated cardiomyocytes is complex. We assumed that adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK)/p38 mitogen-activated protein kinases (p38)/Nrf2 might be involved in resveratrol alleviating MIRI in diabetic rats as an endogenous protective mechanism.
Methods: A total of 50 type 2 diabetes mellitus (T2DM) rat models were randomly divided into 5 groups (n=10 in each group): sham group; MI/R group; AMPK inhibitor compound C + myocardial ischemia-reperfusion (C + MI/R) group; resveratrol + myocardial ischemia-reperfusion (RSV + MI/R) group; and resveratrol + AMPK inhibitor compound C + myocardium ischemia-reperfusion group (RSV + C + MI/R) group. Rats were fed a high fat diet, and the T2DM models were established by intraperitoneal injection of 1% streptozotocin (STZ). The MIRI models were established by ligating the left anterior descending coronary artery for 30 minutes followed by reperfusion for 120 minutes. The size of myocardial infarction was measured. Serum samples were collected to measure the concentrations of creatine kinase-MB (CK-MB). The levels of lactate dehydrogenase (LDH), glutathione (GSH), and superoxide dismutase (SOD) in myocardial tissues were determined. Immunofluorescence analysis of translocase of outer mitochondrial membrane 20 (TOMM20) was performed to observe the pathological changes in myocardial tissues. The protein expressions of AMPK, p-AMPK, p38, p-p38, Nrf2, and heme oxygenase 1 (HO-1) were determined by western blotting.
Results: Compared with the sham group, the expressions of AMPK, p38, Nrf2, and HO-1 in the myocardium were significantly increased in the MI/R group. Compared with the MI/R group, the RSV + MI/R group had a significantly lower oxidative stress level, milder myocardial injury, increased expressions of AMPK, Nrf2, and HO-1, and lower expression of p38. The protein expressions of Nrf2 and HO-1 were partially inhibited in the RSV + C + MI/R group.
Conclusions: Resveratrol can inhibit oxidative stress and alleviate MIRI by activating the AMPK/p38/Nrf2 signaling pathway. Meanwhile, AMPK/p38/Nrf2 is also an endogenous antioxidant stress pathway that protects against stress.

Keywords:  Diabetes; adenosine monophosphate-activated protein kinase (AMPK); myocardial ischemia/reperfusion injury (MIRI); nuclear factor erythroid 2-related factor 2 (Nrf2); resveratrol

DOI:  https://doi.org/10.21037/atm-22-3789
FASEB Bioadv. 2022 Sep;4(9): 602-618

Estrogen-related receptor alpha is an AMPK-regulated factor that promotes ischemic muscle revascularization and recovery in diet-induced obese mice.

Danesh H Sopariwala, Andrea S Rios, Mi Kyung Park, Min Sup Song, Ashok Kumar, Vihang A Narkar.

  Obesity and type II diabetes are leading causes of peripheral arterial disease (PAD), which is characterized by vascular insufficiency and ischemic damage in the limb skeletal muscle. Glycemic control is not sufficient to prevent progression of PAD, and molecular targets that can promote muscle neo-angiogenesis in obesity and diabetes remain poorly defined. Here, we have investigated whether nuclear receptor estrogen-related receptor alpha (ERRα) can promote ischemic revascularization in the skeletal muscles of diet-induced obese (DIO) mice. Using muscle-specific ERRα transgenic mice, we found that ERRα overexpression promotes revascularization, marked by increased capillary staining and muscle perfusion in DIO mice after hindlimb ischemic injury. Furthermore, ERRα facilitates repair and restoration of skeletal muscle myofiber size after limb ischemia in DIO mice. The ameliorative effects of ERRα overexpression did not involve the prevention of weight gain, hyperglycemia or glucose/insulin intolerance, suggesting a direct role for ERRα in promoting angiogenesis. Interestingly, levels of endogenous ERRα protein are suppressed in the skeletal muscles of DIO mice compared to lean controls, coinciding with the suppression of angiogenic gene expression, and reduced AMPK signaling in the DIO skeletal muscles. Upon further investigating the link between AMPK and ERRα, we found that AMPK activation increases the expression and recruitment of ERRα protein to specific angiogenic gene promoters in muscle cells. Further, the induction of angiogenic factors by AMPK activators in muscle cells is blocked by repressing ERRα. In summary, our results identify an AMPK/ERRα-dependent angiogenic gene program in the skeletal muscle, which is repressed by DIO, and demonstrate that forced ERRα activation can promote ischemic revascularization and muscle recovery in obesity.

Keywords:  AMPK; angiogenesis; ischemia; nuclear receptors; obesity; skeletal muscle

DOI:  https://doi.org/10.1096/fba.2022-00015
Chem Biol Interact. 2022 Sep 12. pii: S0009-2797(22)00376-3. [Epub ahead of print] 110171

Sodium selenite inhibits cervical cancer growth via ROS mediated AMPK/FOXO3a /GADD45a axis.

Lei Qi, Yuanyuan Wang, Shengqi Su, Mingxing Wang, Ewa Jablonska, Yuehui Jia, Ruixiang Wang, Shuxiu Hao, Chen Feng, Guijin Li, Meijing Jiang, Linlin Du, Huixin Sun, Qi Li, Tong Wang.

  Selenium is a trace element that has been shown to inhibit the growth of various cancer cell types. However, its role in cervical cancer and its underlying mechanisms remains largely unknown. Herein, we explored the anti-cervical cancer effect of selenium and its potential mechanisms through xenograft and in vitro experiments. HeLa cell xenografts in female nude mice showed tumor growth retardation, with no obvious liver and kidney toxicity, after being intraperitoneally injected with 3 mg/kg sodium selenite (SS) for 14 days. Compared to the control group, selenium levels in the tumor tissue increased significantly after SS treatment. In vitro experiments, SS inhibited the viability of HeLa and SiHa cells, blocked the cell cycle at the S phase, and enhanced apoptosis. RNA-sequencing, Kyoto encyclopedia of genes and genomes pathway analysis showed that forkhead box protein O (FOXO) was a key regulatory signaling pathway for SS to exhibit anticancer effects. Gene Ontology analysis filtered multiple terms associated with apoptosis, anti-proliferation, and cell cycle arrest. Further research revealed that SS increased intracellular reactive oxygen species (ROS) and impaired mitochondrial function, which activated adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) via phosphorylation at Thr172, resulting in activation of FOXO3a and its downstream growth arrest and DNA damage-inducible alpha (GADD45a). In summary, SS exhibited anti-cervical cancer effects, and their mechanisms may be that SS is involved in inducing cell cycle arrest and potentiating cell apoptosis caused by ROS-dependent activation of the AMPK/FOXO3a/GADD45a axis.

Keywords:  AMPK/FOXO3a/GADD45a pathway; Cervical cancer; RNA-Sequencing; Reactive oxygen species; Sodium selenite

DOI:  https://doi.org/10.1016/j.cbi.2022.110171
J Appl Physiol (1985). 2022 Sep 15.

Skeletal muscle contraction kinetics and AMPK responses are modulated by the adenine nucleotide degrading enzyme AMPD1.

Paul S Hafen, Andrew S Law, Catalina Matias, Spencer G Miller, Jeffrey J Brault.

  AMP deaminase 1 (AMPD1; AMP → IMP + NH3) deficiency in skeletal muscle results in an inordinate accumulation of AMP during strenuous exercise, with some but not all studies reporting premature fatigue and reduced work capacity. To further explore these inconsistencies, we investigated the extent to which AMPD1 deficiency impacts skeletal muscle contractile function of different muscles and the [AMP]/AMPK responses to different intensities of fatiguing contractions. To reduce AMPD1 protein, we electroporated either an inhibitory AMPD1-specific miRNA encoding plasmid, or a control plasmid, into contralateral EDL and SOL muscles of C57BL/6J mice (n = 48 male, 24 female). After ten days, isolated muscles were assessed for isometric twitch, tetanic, and repeated fatiguing contraction characteristics using one of four (None, LOW, MOD, HIGH) duty cycles. AMPD1 knockdown (~35%) had no effect on twitch force or twitch contraction/relaxation kinetics. However, during maximal tetanic contractions, AMPD1 knockdown impaired both time-to-peak tension (TPT) and half-relaxation time (1/2 RT) in EDL, but not SOL muscle. In addition, AMPD1 knockdown in EDL exaggerated the AMP response to contractions at LOW (+100%) and MOD (+54%) duty cycles, but not HIGH. This accumulation of AMP was accompanied by increased AMPK phosphorylation (Thr-172; LOW +25%, MOD +34%) and downstream substrate phosphorylation (LOW +15%, MOD +17%). These responses to AMPD1 knockdown were not different between males and females. Our findings demonstrate that AMPD1 plays a role in maintaining skeletal muscle contractile function and regulating the energetic responses associated with repeated contractions in a muscle- but not sex-specific manner.

Keywords:  AMP deaminase; AMP-activated Protein kinase; Fatigue; Muscle contraction; Sex differences

DOI:  https://doi.org/10.1152/japplphysiol.00035.2022
Autophagy. 2022 Sep 15.

cAMP-Protein Kinase A and Stress-Activated MAP Kinase signaling mediate transcriptional control of autophagy in fission yeast during glucose limitation or starvation.

Armando Jesús Pérez-Díaz, Beatriz Vázquez-Marín, Jero Vicente-Soler, Francisco Prieto-Ruiz, Teresa Soto, Alejandro Franco, José Cansado, Marisa Madrid.

  Macroautophagy/autophagy is an essential adaptive physiological response in eukaryotes induced during nutrient starvation, including glucose, the primary immediate carbon and energy source for most cells. Although the molecular mechanisms that induce autophagy during glucose starvation have been extensively explored in the budding yeast Saccharomyces cerevisiae, little is known about how this coping response is regulated in the evolutionary distant fission yeast Schizosaccharomyces pombe. Here, we show that S. pombe autophagy in response to glucose limitation relies on mitochondrial respiration and the electron transport chain (ETC), but, in contrast to S. cerevisiae, the AMP-activated protein kinase (AMPK) and DNA damage response pathway components do not modulate fission yeast autophagic flux under these conditions. In the presence of glucose, the cAMP-protein kinase A (PKA) signaling pathway constitutively represses S. pombe autophagy by downregulating the transcription factor Rst2, which promotes the expression of respiratory genes required for autophagy induction under limited glucose availability. Furthermore, the stress-activated protein kinase (SAPK) signaling pathway, and its central mitogen-activated protein kinase (MAPK) Sty1, positively modulate autophagy upon glucose limitation at the transcriptional level through its downstream effector Atf1 and by direct in vivo phosphorylation of Rst2 at S292. Thus, our data indicate that the signaling pathways that govern autophagy during glucose shortage or starvation have evolved differently in S. pombe and uncover the existence of sophisticated and multifaceted mechanisms that control this self-preservation and survival response.

Keywords:  Autophagy; MAP kinase; Schizosaccharomyces pombe; cAMP-protein kinase A; fermentation; glucose; respiration; transcription

DOI:  https://doi.org/10.1080/15548627.2022.2125204
Front Cell Dev Biol. 2022 ;10 987317

Sensing local energetics to acutely regulate mitophagy in skeletal muscle.

Anna S Nichenko, Kalyn S Specht, Siobhan M Craige, Joshua C Drake.

  The energetic requirements of skeletal muscle to sustain movement, as during exercise, is met largely by mitochondria, which form an intricate, interconnected reticulum. Maintenance of a healthy mitochondrial reticulum is essential for skeletal muscle function, suggesting quality control pathways are spatially governed. Mitophagy, the process by which damaged and/or dysfunctional regions of the mitochondrial reticulum are removed and degraded, has emerged as an integral part of the molecular response to exercise. Upregulation of mitophagy in response to acute exercise is directly connected to energetic sensing mechanisms through AMPK. In this review, we discuss the connection of mitophagy to muscle energetics and how AMPK may spatially control mitophagy through multiple potential means.

Keywords:  AMPK; energetic stress; mitochondria; mitophagy; reactive oxygen species

DOI:  https://doi.org/10.3389/fcell.2022.987317
iScience. 2022 Sep 16. 25(9): 105029

MCM7 supports the stemness of bladder cancer stem-like cells by enhancing autophagic flux.

Lijun Mo, Bijia Su, Lili Xu, Zhiming Hu, Hongwei Li, Hongyan Du, Jinlong Li.

  Autophagy plays critical roles in the pluripotent stemness of cancer stem cells (CSCs). However, how CSCs maintain the elevated autophagy to support stemness remains elusive. Here, we demonstrate that bladder cancer stem-like cells (BCSLCs) are at slow-cycling state with enhanced autophagy and mitophagy. In these slow-cycling BCSLCs, the DNA replication initiator MCM7 is required for autophagy and stemness. MCM7 knockdown inhibits autophagic flux and reduces the stemness of BCSLCs. MCM7 can facilitate autolysosome formation through binding with dynein to promote autophagic flux. The enhanced autophagy/mitophagy helps BCSLCs to maintain mitochondrial respiration, thus inhibiting AMPK activation. AMPK activation can trigger switch from autophagy to apoptosis, through increasing BCL2/BECLIN1 interaction and inducing P53 accumulation. In summary, we find that MCM7 can promote autophagic flux to support.

Keywords:  Biological sciences; Cancer; Stem cells research; Systems biology

DOI:  https://doi.org/10.1016/j.isci.2022.105029
Front Pharmacol. 2022 ;13 940406

Co-Treatment With Resveratrol and FGF1 Protects Against Acute Liver Toxicity After Doxorubicin Treatment via the AMPK/NRF2 Pathway.

Xianchou Xu, Qingbo Liu, Jiahao Li, Mengjie Xiao, Ting Gao, Xiaohui Zhang, Guangping Lu, Jie Wang, Yuanfang Guo, Peinan Wen, Junlian Gu.

  Doxorubicin (DOX), an anthracycline type of chemotherapy, is an effective therapy for several types of cancer, but serious side effects, such as severe hepatotoxicity, limit its use currently. Accordingly, an effective therapeutic strategy to prevent DOX-related hepatotoxicity is urgently needed. Through the inhibition of oxidative stress, fibroblast growth factor 1 (FGF1) is an effect therapy for a variety of liver diseases, but its use is limited by an increased risk of tumorigenesis due to hyperproliferation. Resveratrol (RES), a natural product, inhibits the growth of many cancer cell lines, including liver, breast, and prostate cancer cells. Therefore, this study explored whether and how RES in combination with FGF1 can alleviate DOX-induced hepatotoxicity. The results showed that RES or FGF1 alone improved DOX-induced hepatic inflammation, apoptosis and oxidative stress, and these adverse effects were further attenuated after treatment with both RES and FGF1. Mechanistically, both in vivo and in vitro results showed that RES/FGF1 reduced oxidative stress and thereby alleviated liver injury by promoting nuclear translocation of nuclear factor erythroid 2-related factor 2 (NRF2) and subsequently upregulating expression of antioxidant proteins in an adenosine monophosphate-activated protein kinase (AMPK)-dependent manner. Together, our results not only demonstrate that co-treatment with RES and FGF1 significantly inhibited DOX-induced hepatic inflammation and apoptosis, but also that co-treatment with RES and FGF1 markedly suppressed DOX-induced hepatic oxidative stress, via targeting the AMPK/NRF2 pathway and subsequently ameliorating hepatic dysfunction. Thus, the combination of RES and FGF1 may provide a new therapeutic strategy for limiting DOX-induced hepatotoxicity.

Keywords:  AMPK; NRF2; doxorubicin; hepatotoxicity; oxidative stress

DOI:  https://doi.org/10.3389/fphar.2022.940406
Sci Adv. 2022 Sep 16. 8(37): eabo0323

An AMPK phosphoregulated RhoGEF feedback loop tunes cortical flow-driven amoeboid migration in vivo.

Benjamin Lin, Jonathan Luo, Ruth Lehmann.

Development, morphogenesis, immune system function, and cancer metastasis rely on the ability of cells to move through diverse tissues. To dissect migratory cell behavior in vivo, we developed cell type-specific imaging and perturbation techniques for Drosophila primordial germ cells (PGCs). We find that PGCs use global, retrograde cortical actin flows for orientation and propulsion during guided developmental homing. PGCs use RhoGEF2, a RhoA-specific RGS-RhoGEF, as a dose-dependent regulator of cortical flow through a feedback loop requiring its conserved PDZ and PH domains for membrane anchoring and local RhoA activation. This feedback loop is regulated for directional migration by RhoGEF2 availability and requires AMPK rather than canonical Gα12/13 signaling. AMPK multisite phosphorylation of RhoGEF2 near a conserved EB1 microtubule-binding SxIP motif releases RhoGEF2 from microtubule-dependent inhibition. Thus, we establish the mechanism by which global cortical flow and polarized RhoA activation can be dynamically adapted during natural cell navigation in a changing environment.

DOI: https://doi.org/10.1126/sciadv.abo0323
Oxid Med Cell Longev. 2022 ;2022 3737137

Ginsenoside Rg1 Ameliorates Acute Renal Ischemia/Reperfusion Injury via Upregulating AMPKα1 Expression.

Qing Zhou, Xinlan He, Xiaoyu Zhao, Qigui Fan, Songqing Lai, Dan Liu, Huan He, Ming He.

Acute renal ischemia/reperfusion (I/R) injury often occurs during kidney transplantation and other kidney surgeries, and the molecular mechanism involves oxidative stress. We hypothesized that ginsenoside Rg1 (Rg1), a saponin derived from ginseng, would protect the renal tissue against acute renal I/R injury by upregulating 5' adenosine monophosphate-activated protein kinase α1 (AMPKα1) expression and inhibiting oxidative stress. The models of acute anoxia/reoxygenation (A/R) damage in normal rat kidney epithelial cell lines (NRK-52E) and acute renal I/R injury in mice were constructed. The results revealed that pretreatment with 25 μM Rg1 significantly increased NRK-52E viability, decreased lactate dehydrogenase (LDH) activity and apoptosis, suppressed reactive oxygen species generation and oxidative stress, stabilized mitochondrial membrane potential and reduced mitochondria permeability transition pore openness, decreased adenosine monophosphate/adenosine triphosphate ratio, and upregulated the expression of AMPKα1, cytochrome b-c1 complex subunit 2, NADH dehydrogenase (ubiquinone) 1 beta subcomplex subunit 8, and B-cell lymphoma 2, while downregulating BCL2-associated X protein expression. The effects of Rg1 pretreatment were similar to those of pAD/Flag-AMPKα1. After acute renal I/R injury, serum creatinine, blood urea nitrogen, LDH activity, and oxidative stress in renal tissue significantly increased. Rg1 pretreatment upregulated AMPKα1 expression, which protects against acute renal I/R injury by maintaining renal function homeostasis, inhibiting oxidative stress, and reducing apoptosis. Compound C, a specific inhibitor of AMPK, reversed the effects of Rg1. In summary, Rg1 pretreatment upregulated AMPKα1 expression, inhibited oxidative stress, maintained mitochondrial function, improved energy metabolism, reduced apoptosis, and ultimately protected renal tissue against acute renal I/R injury.

DOI: https://doi.org/10.1155/2022/3737137
Ann Transl Med. 2022 Aug;10(16): 900

Zhuanggu Zhitong Capsule alleviates postmenopausal osteoporosis in ovariectomized rats by regulating autophagy through AMPK/mTOR signaling pathway.

Zhitao Men, Chengjun Huang, Min Xu, Jiangtao Ma, Lei Wan, Jiachun Huang, Yanping Lin, Jiayao Yuan, Hong Huang, Hongxing Huang.

   Background: Postmenopausal osteoporosis (PMOP) is the most common primary osteoporosis, which is prone to fractures and affect the health and quality of life of the elderly and even shorten their lifetime. Traditional Chinese medicine can not only effectively improve osteoporosis and reduce fracture rate, but also have tonifying and analgesic effects. The purpose of this study was to investigate the effects of Zhuanggu Zhitong (ZGZT) Capsule on autophagy related genes and proteins in PMOP rats, so as to elucidate the molecular mechanism of tonifying deficiency and regulating stasis in the treatment of osteoporosis and analgesia.
Methods: The PMOP rat model was established by bilateral oophorectomy, and then the rats were randomly divided into control group, PMOP group, PMOP + ZGZT group and PMOP + E2 group. The changes of mechanical pain threshold of rats were detected by von Frey filaments, and the changes of mechanical pain threshold of rats in each group were compared. Computed tomography (CT) and dual-energy X-ray were used to measure the bone mineral density of lumbar bone tissue. Enzyme-linked immunosorbent assay (ELISA) and tartrate-resistant acid phosphatase (TRAP) staining were used to detect inflammatory factors and bone metabolism related indicators. Hematoxylin-eosin (HE) staining was used to observe the tissue morphology of lumbar vertebra tissue. Western blot (WB) and quantitative polymerase chain reaction (qPCR) were used to detect AMPK/mTOR pathway- and autophagy-related factor expression.
Results: ZGZT can effectively restore the bone mineral density (BMD) of PMOP rats, improve the microstructure of lumbar vertebra of PMOP rats, restore the balance of bone metabolism, promote the expression of AMPK and autophagy related factors, inhibit the expression of mTOR and the release of inflammatory factors, and increase the mechanical pain threshold of PMOP rats, so as to effectively improve osteoporosis and relieving osteoporosis pain in PMOP rats.
Conclusions: ZGZT affects autophagy by regulating AMPK/mTOR pathway, restores the homeostasis of bone metabolism and inhibits the release of inflammatory factors. Moreover, the regulation of feedback pathways between bone metabolism and inflammatory factors finally plays the role of "bone strengthening" and "pain relieving". ZGZT may be a new treatment for PMOP and relieving osteoporotic pain.

Keywords:  Adenosine 5’-monophosphate-activated protein kinase (AMPK); autophagy; inflammatory factor; mammalian target of rapamycin (mTOR); postmenopausal osteoporosis (PMOP)

DOI:  https://doi.org/10.21037/atm-22-3724
J Cell Mol Med. 2022 Sep 16.

NANOG regulates epithelial-mesenchymal transition via AMPK/mTOR signalling pathway in ovarian cancer SKOV-3 and A2780 cells.

Hee Yun, Gwan Hee Han, Julie Kim, Joon-Yong Chung, Jae-Hoon Kim, Hanbyoul Cho.

  NANOG engages with tumour initiation and metastasis by regulating the epithelial-mesenchymal transition (EMT) in epithelial ovarian cancer (EOC). However, its role in association with pAMPKα, and its clinical significance in EOC have not been elucidated even though AMPK is known to degrade NANOG in various human cancers. Hence, we investigated the role of pAMPKα and its association with NANOG as potential prognostic biomarkers in EOC. Both NANOG and pAMPKα expression were significantly overexpressed in EOCs comparing nonadjacent normal epithelial tissues, benign tissues, and borderline tumours. NANOG overexpression was significantly associated with poor disease-free survival (DFS) and overall survival (OS), whereas pAMPKα overexpression was associated with good DFS and OS. Importantly, multivariate analysis revealed that the combination of high NANOG and low pAMPKα expression was a poor independent prognostic factor for DFS and was associated with platinum resistance. In ovarian cancer cell lines, siRNA-mediated NANOG knockdown diminished migration and invasion properties by regulating the EMT process via the AMPK/mTOR signalling pathway. Furthermore, treatment with AMPK activator suppressed expression of stemness factors such as NANOG, Oct4 and Sox2. Collectively, these findings established that the combination of high NANOG and low pAMPKα expression was associated with EOC progression and platinum resistance, suggesting a potential prognostic biomarker for clinical management in EOC patients.

Keywords:  NANOG; epithelial-mesenchymal transition; mTOR; ovarian cancer; pAMPK

DOI:  https://doi.org/10.1111/jcmm.17557