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Wang H, Kwak SE, Zheng A, Arias EB, Pan X, Duan D, Cartee GD. Phosphorylation of AS160-serine 704 is not essential for exercise-increase in insulin-stimulated glucose uptake by skeletal muscles from female or male rats. Am J Physiol Endocrinol Metab 2024; 326:E807-E818. [PMID: 38656130 PMCID: PMC11376492 DOI: 10.1152/ajpendo.00010.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 03/18/2024] [Accepted: 04/07/2024] [Indexed: 04/26/2024]
Abstract
One exercise session can increase subsequent insulin-stimulated glucose uptake (ISGU) by skeletal muscle from rodents and humans of both sexes. We recently found that concurrent mutation of three key sites to prevent their phosphorylation (Ser588, Thr642, and Ser704) on Akt substrate of 160 kDa (AS160; also known as TBC1D4) reduced the magnitude of the enhancement of postexercise ISGU (PEX-ISGU) by muscle from male, but not female rats. However, we did not test the role of individual phosphorylation sites on PEX-ISGU. Accordingly, our current aim was to test whether AS160 Ser704 phosphorylation (pSer704) is required for elevated PEX-ISGU by muscle. AS160-knockout (AS160-KO) rats (female and male) were studied when either in sedentary or 3 h after acute exercise. Adeno-associated virus (AAV) vectors were used to enable muscle expression of wild-type AS160 (AAV-WT-AS160) or AS160 mutated Ser704 to alanine to prevent phosphorylation (AAV-1P-AS160). Paired epitrochlearis muscles from each rat were injected with AAV-WT-AS160 or AAV-1P-AS160. We discovered that regardless of sex 1) AS160 abundance in AS160-KO rats was similar in paired muscles expressing WT-AS160 versus 1P-AS160; 2) muscles from exercised versus sedentary rats had greater ISGU, and PEX-ISGU was slightly greater for muscles expressing 1P-AS160 versus contralateral muscles expressing WT-AS160; and 3) pAS160Thr642 was lower in muscles expressing 1P-AS160 versus paired muscles expressing WT-AS160. These results indicate that pAS160Ser704 was not essential for elevated PEX-ISGU by skeletal muscle from rats of either sex. Furthermore, elimination of the postexercise increase in pAS160Thr642 did not lessen the postexercise effect on ISGU.NEW & NOTEWORTHY The current study evaluated the role of Akt substrate of 160 kDa (AS160) phosphorylation on Ser704 in increased insulin-stimulated glucose uptake by skeletal muscle after exercise. Adeno-associated virus vectors were engineered to express either wild-type-AS160 or AS160 mutated so that it could not be phosphorylated on Ser704 in paired muscles from AS160-knockout rats. The results demonstrated that AS160 phosphorylation on Ser704 was not essential for exercise-induced elevation in insulin-stimulated glucose uptake by rats of either sex.
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Affiliation(s)
- Haiyan Wang
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States
| | - Seong Eun Kwak
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States
| | - Amy Zheng
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States
| | - Edward B Arias
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States
| | - Xiufang Pan
- Department of Molecular Microbiology and Immunology, University of Missouri, Columbia, Missouri, United States
| | - Dongsheng Duan
- Department of Molecular Microbiology and Immunology, University of Missouri, Columbia, Missouri, United States
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, United States
- Department of Neurology, School of Medicine, University of Missouri, Columbia, Missouri, United States
- Department of Chemical and Biomedical Engineering, College of Engineering, University of Missouri, Columbia, Missouri, United States
| | - Gregory D Cartee
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan, United States
- Institute of Gerontology, University of Michigan, Ann Arbor, Michigan, United States
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Hoermann B, Dürr EM, Ludwig C, Ercan M, Köhn M. A strategy to disentangle direct and indirect effects on (de)phosphorylation by chemical modulators of the phosphatase PP1 in complex cellular contexts. Chem Sci 2024; 15:2792-2804. [PMID: 38404380 PMCID: PMC10882499 DOI: 10.1039/d3sc04746f] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 01/12/2024] [Indexed: 02/27/2024] Open
Abstract
Chemical activators and inhibitors are useful probes to identify substrates and downstream effects of enzymes; however, due to the complex signaling environment within cells, it is challenging to distinguish between direct and indirect effects. This is particularly the case for phosphorylation, where a single (de)phosphorylation event can trigger rapid changes in many other phosphorylation sites. An additional complication arises when a single catalytic entity, which acts in the form of many different holoenzymes with different substrates, is activated or inhibited, as it is unclear which holoenzymes are affected, and in turn which of their substrates are (de)phosphorylated. Direct target engaging MS-based technologies to study targets of drugs do not address these challenges. Here, we tackle this by studying the modulation of protein phosphatase-1 (PP1) activity by PP1-disrupting peptides (PDPs), as well as their selectivity toward PP1, by using a combination of mass spectrometry-based experiments. By combining cellular treatment with the PDP with in vitro dephosphorylation by the enzyme, we identify high confidence substrate candidates and begin to separate direct and indirect effects. Together with experiments analyzing which holoenzymes are particularly susceptible to this treatment, we obtain insights into the effect of the modulator on the complex network of protein (de)phosphorylation. This strategy holds promise for enhancing our understanding of PP1 in particular and, due to the broad applicability of the workflow and the MS-based read-out, of chemical modulators with complex mode of action in general.
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Affiliation(s)
- Bernhard Hoermann
- Faculty of Biology, Institute of Biology III, University of Freiburg Freiburg Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg Freiburg Germany
| | - Eva-Maria Dürr
- Faculty of Biology, Institute of Biology III, University of Freiburg Freiburg Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg Freiburg Germany
| | - Christina Ludwig
- Chair of Proteomics and Bioanalytics, Technical University of Munich (TUM) Freising Germany
- Bavarian Center for Biomolecular Mass Spectrometry (BayBioMS), Technical University of Munich (TUM) Freising Germany
| | - Melda Ercan
- Faculty of Biology, Institute of Biology III, University of Freiburg Freiburg Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg Freiburg Germany
| | - Maja Köhn
- Faculty of Biology, Institute of Biology III, University of Freiburg Freiburg Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg Freiburg Germany
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Wu C, Zhang W, Luo Y, Cheng C, Wang X, Jiang Y, Li S, Luo L, Yang Y. Zebrafish ppp1r21 mutant as a model for the study of primary biliary cholangitis. J Genet Genomics 2023; 50:1004-1013. [PMID: 37271428 DOI: 10.1016/j.jgg.2023.05.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 05/05/2023] [Accepted: 05/22/2023] [Indexed: 06/06/2023]
Abstract
Primary biliary cholangitis (PBC) is an autoimmune cholestatic liver disease that progresses to fibrosis and cirrhosis, resulting from the gradual destruction of intrahepatic bile ducts. Exploring genetic variants associated with PBC is essential to understand the pathogenesis of PBC. Here we identify a zebrafish balloon dog (blg) mutant with intrahepatic bile duct branching defects, exhibiting several key pathological PBC-like features, including immunodominant autoantigen PDC-E2 production, cholangiocyte apoptosis, immune cell infiltration, inflammatory activation, and liver fibrosis. blg encodes the protein phosphatase 1 regulatory subunit 21 (Ppp1r21), which is enriched in the liver and its peripheral tissues and plays a vital role in the early intrahepatic bile duct formation stage. Further studies show an excessive activation of the PI3K/AKT/mTOR pathway in the hepatic tissues in the mutant, while treatment with the pathway inhibitor LY294002 and rapamycin partially rescues intrahepatic bile duct branching defects and alleviates the PBC-like symptoms. These findings implicate the potential role of the Ppp1r21-mediated PI3K/AKT/mTOR pathway in the pathophysiology of PBC.
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Affiliation(s)
- Chaoying Wu
- Institute of Developmental Biology and Regenerative Medicine, Southwest University, Beibei, Chongqing 400715, China
| | - Wenfeng Zhang
- Institute of Developmental Biology and Regenerative Medicine, Southwest University, Beibei, Chongqing 400715, China
| | - Yiyu Luo
- Institute of Developmental Biology and Regenerative Medicine, Southwest University, Beibei, Chongqing 400715, China
| | - Chaoqing Cheng
- Institute of Developmental Biology and Regenerative Medicine, Southwest University, Beibei, Chongqing 400715, China
| | - Xinjuan Wang
- Institute of Developmental Biology and Regenerative Medicine, Southwest University, Beibei, Chongqing 400715, China
| | - Yan Jiang
- Institute of Developmental Biology and Regenerative Medicine, Southwest University, Beibei, Chongqing 400715, China
| | - Shuang Li
- Institute of Developmental Biology and Regenerative Medicine, Southwest University, Beibei, Chongqing 400715, China
| | - Lingfei Luo
- Institute of Developmental Biology and Regenerative Medicine, Southwest University, Beibei, Chongqing 400715, China
| | - Yun Yang
- Institute of Developmental Biology and Regenerative Medicine, Southwest University, Beibei, Chongqing 400715, China.
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Manzano M, Girón MD, Salto R, Burgio C, Reinoso A, Cabrera E, Rueda R, López-Pedrosa JM. Arginine and Lysine Supplementation Potentiates the Beneficial β-Hydroxy ß-Methyl Butyrate (HMB) Effects on Skeletal Muscle in a Rat Model of Diabetes. Nutrients 2023; 15:4706. [PMID: 38004100 PMCID: PMC10674618 DOI: 10.3390/nu15224706] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 11/02/2023] [Accepted: 11/04/2023] [Indexed: 11/26/2023] Open
Abstract
Skeletal muscle is the key tissue for maintaining protein and glucose homeostasis, having a profound impact on the development of diabetes. Diabetes causes deleterious changes in terms of loss of muscle mass, which will contribute to reduced glucose uptake and therefore progression of the disease. Nutritional approaches in diabetes have been directed to increase muscle glucose uptake, and improving protein turnover has been at least partially an oversight. In muscle, β-hydroxy β-methyl butyrate (HMB) promotes net protein synthesis, while arginine and lysine increase glucose uptake, albeit their effects on promoting protein synthesis are limited. This study evaluates if the combination of HMB, lysine, and arginine could prevent the loss of muscle mass and function, reducing the progression of diabetes. Therefore, the combination of these ingredients was tested in vitro and in vivo. In muscle cell cultures, the supplementation enhances glucose uptake and net protein synthesis due to an increase in the amount of GLUT4 transporter and stimulation of the insulin-dependent signaling pathway involving IRS-1 and Akt. In vivo, using a rat model of diabetes, the supplementation increases lean body mass and insulin sensitivity and decreases blood glucose and serum glycosylated hemoglobin. In treated animals, an increase in GLUT4, creatine kinase, and Akt phosphorylation was detected, demonstrating the synergic effects of the three ingredients. Our findings showed that nutritional formulations based on the combination of HMB, lysine, and arginine are effective, not only to control blood glucose levels but also to prevent skeletal muscle atrophy associated with the progression of diabetes.
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Affiliation(s)
- Manuel Manzano
- Abbott Nutrition R&D, E18004 Granada, Spain; (M.M.); (R.R.); (J.M.L.-P.)
| | - María D. Girón
- Department of Biochemistry and Molecular Biology II, School of Pharmacy, University of Granada, E18071 Granada, Spain; (M.D.G.); (C.B.); (A.R.); (E.C.)
| | - Rafael Salto
- Department of Biochemistry and Molecular Biology II, School of Pharmacy, University of Granada, E18071 Granada, Spain; (M.D.G.); (C.B.); (A.R.); (E.C.)
| | - Chiara Burgio
- Department of Biochemistry and Molecular Biology II, School of Pharmacy, University of Granada, E18071 Granada, Spain; (M.D.G.); (C.B.); (A.R.); (E.C.)
| | - Antonio Reinoso
- Department of Biochemistry and Molecular Biology II, School of Pharmacy, University of Granada, E18071 Granada, Spain; (M.D.G.); (C.B.); (A.R.); (E.C.)
| | - Elena Cabrera
- Department of Biochemistry and Molecular Biology II, School of Pharmacy, University of Granada, E18071 Granada, Spain; (M.D.G.); (C.B.); (A.R.); (E.C.)
| | - Ricardo Rueda
- Abbott Nutrition R&D, E18004 Granada, Spain; (M.M.); (R.R.); (J.M.L.-P.)
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Yadav Y, Sharma M, Dey CS. PP1γ regulates neuronal insulin signaling and aggravates insulin resistance leading to AD-like phenotypes. Cell Commun Signal 2023; 21:82. [PMID: 37085815 PMCID: PMC10120118 DOI: 10.1186/s12964-023-01071-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 02/08/2023] [Indexed: 04/23/2023] Open
Abstract
BACKGROUND PP1γ is one of the isoforms of catalytic subunit of a Ser/Thr phosphatase PP1. The role of PP1γ in cellular regulation is largely unknown. The present study investigated the role of PP1γ in regulating neuronal insulin signaling and insulin resistance in neuronal cells. PP1 was inhibited in mouse neuroblastoma cells (N2a) and human neuroblastoma cells (SH-SY5Y). The expression of PP1α and PP1γ was determined in insulin resistant N2a, SH-SY5Y cells and in high-fat-diet-fed-diabetic mice whole-brain-lysates. PP1α and PP1γ were silenced by siRNA in N2a and SH-SY5Y cells and effect was tested on AKT isoforms, AS160 and GSK3 isoforms using western immunoblot, GLUT4 translocation by confocal microscopy and glucose uptake by fluorescence-based assay. RESULTS Results showed that, in one hand PP1γ, and not PP1α, regulates neuronal insulin signaling and insulin resistance by regulating phosphorylation of AKT2 via AKT2-AS160-GLUT4 axis. On the other hand, PP1γ regulates phosphorylation of GSK3β via AKT2 while phosphorylation of GSK3α via MLK3. Imbalance in this regulation results into AD-like phenotype. CONCLUSION PP1γ acts as a linker, regulating two pathophysiological conditions, neuronal insulin resistance and AD. Video Abstract.
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Affiliation(s)
- Yamini Yadav
- Kusuma School of Biological Sciences, Indian Institute of Technology, Delhi, New Delhi, 110016, India
| | - Medha Sharma
- Kusuma School of Biological Sciences, Indian Institute of Technology, Delhi, New Delhi, 110016, India
| | - Chinmoy Sankar Dey
- Kusuma School of Biological Sciences, Indian Institute of Technology, Delhi, New Delhi, 110016, India.
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6
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Yadav Y, Dey CS. Ser/Thr phosphatases: One of the key regulators of insulin signaling. Rev Endocr Metab Disord 2022; 23:905-917. [PMID: 35697962 DOI: 10.1007/s11154-022-09727-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/18/2022] [Indexed: 10/18/2022]
Abstract
Protein phosphorylation is an important post-translational modification that regulates several cellular processes including insulin signaling. The evidences so far have already portrayed the importance of balanced actions of kinases and phosphatases in regulating the insulin signaling cascade. Therefore, elucidating the role of both kinases and phosphatases are equally important. Unfortunately, the role of phosphatases is less studied as compared to kinases. Since brain responds to insulin and insulin signaling is reported to be crucial for many neuronal processes, it is important to understand the role of neuronal insulin signaling regulators. Ser/Thr phosphatases seem to play significant roles in regulating neuronal insulin signaling. Therefore, in this review, we discussed the involvement of Ser/Thr phosphatases in regulating insulin signaling and insulin resistance in neuronal system at the backdrop of the same phosphatases in peripheral insulin sensitive tissues.
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Affiliation(s)
- Yamini Yadav
- Kusuma School of Biological Sciences, Indian Institute of Technology, Delhi, New Delhi, 110016, India
| | - Chinmoy Sankar Dey
- Kusuma School of Biological Sciences, Indian Institute of Technology, Delhi, New Delhi, 110016, India.
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7
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Huang L, Gong J, Hu Y, Tan QL, Liu B, Yu XW, Hao XL, Guo QN. Long-term exposure to low levels of okadaic acid accelerates cell cycle progression in colonic epithelial cells via p53 and Jak/Stat3 signaling pathways. Heliyon 2022; 8:e10444. [PMID: 36105456 PMCID: PMC9465354 DOI: 10.1016/j.heliyon.2022.e10444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 07/04/2022] [Accepted: 08/22/2022] [Indexed: 11/30/2022] Open
Abstract
As a major component of diarrheic shellfish poisoning (DSP) toxins, okadaic acid (OA) is widely distributed worldwide, and causes a series of serious public health problems. In colon tissue, previous studies have shown that high doses of OA can affect various intracellular processes, including destroy intercellular communication at gap junctions, induce cell apoptosis and trigger cell cycle arrest. However, there is a scarcity of studies on the effect and mechanism of action of low doses of OA in colonic tissues. In this study, we observed that exposure to low levels of OA altered cell cycle progression in vitro and in vivo. Investigation of the underlying mechanism revealed that OA induced alterations in the cell cycle by inhibiting the p53 signaling pathway or inducing the Jak/Stat3 signaling pathway. In conclusion, this study provides novel insights into the effect and mechanism underlying long-term exposure to low levels of OA. Long-term exposure to low levels of OA accelerates cell cycles in vitro and in vivo OA induced changes in cell cycle by inhibiting the p53 signaling pathway OA induced changes in cell cycle by inducing the Jak/Stat3 signaling pathway
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Wang B, Luo X, Li RR, Li YN, Zhao YC. Effect of resistance exercise on insulin sensitivity of skeletal muscle. World J Meta-Anal 2021; 9:101-107. [DOI: 10.13105/wjma.v9.i2.101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 03/10/2021] [Accepted: 04/23/2021] [Indexed: 02/06/2023] Open
Abstract
Insulin resistance (IR) is the common pathophysiological basis of many metabolic diseases. IR is characterized by decreased glucose uptake in skeletal muscle and adipose tissue, especially in skeletal muscle. Skeletal muscle is the main target tissue of glucose uptake under insulin stimulation. Glucose uptake by skeletal muscle is complex, and it is controlled by many pathways. The PI3K/AKt/GSK-1 signaling pathway is not only the main pathway for insulin signal transduction but also an important mechanism for regulating blood glucose. From the binding of insulin to its receptors on the surface of target cells to the transportation of glucose from extracellular fluid to skeletal muscle, a series of signal transduction processes is completed, any of which potentially affects the physiological effects of insulin and leads to IR. Resistance exercise (RT) can reduce skeletal muscle IR and effectively improve blood glucose control and glycosylated hemoglobin level in patients with type 2 diabetes mellitus (T2DM). However, the exact mechanism by which RT improves skeletal muscle IR remains unclear. Therefore, this paper discusses the above problems by tracking the progress of the literature to deepen the correlation between RT and skeletal muscle insulin sensitivity and provide further evidence for the application of exercise therapy in IR. In conclusion, RT mainly improves insulin sensitivity of skeletal muscle by increasing muscle mass, microvascular blood flow, and glucose transporter-4 expression in skeletal muscle, as well as by reducing lipid accumulation and inflammation in skeletal muscle. Thus, it is potentially useful in the prevention and treatment of T2DM.
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Affiliation(s)
- Bo Wang
- Department of Internal Medicine, Yantaishan Hospital, Yantai 264001, Shandong Province, China
| | - Xu Luo
- Department of Pathophysiology, School of Basic Medicine, Binzhou Medical University, Yantai 264003, Shandong Province, China
| | - Rong-Rong Li
- Department of Pathophysiology, School of Basic Medicine, Binzhou Medical University, Yantai 264003, Shandong Province, China
| | - Ya-Na Li
- Department of Pathophysiology, School of Basic Medicine, Binzhou Medical University, Yantai 264003, Shandong Province, China
| | - Yu-Chi Zhao
- Department of Osteoarthropathy, Yantaishan Hospital, Yantai 264001, Shandong Province, China
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Excess Accumulation of Lipid Impairs Insulin Sensitivity in Skeletal Muscle. Int J Mol Sci 2020; 21:ijms21061949. [PMID: 32178449 PMCID: PMC7139950 DOI: 10.3390/ijms21061949] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 03/09/2020] [Accepted: 03/10/2020] [Indexed: 12/12/2022] Open
Abstract
Both glucose and free fatty acids (FFAs) are used as fuel sources for energy production in a living organism. Compelling evidence supports a role for excess fatty acids synthesized in intramuscular space or dietary intermediates in the regulation of skeletal muscle function. Excess FFA and lipid droplets leads to intramuscular accumulation of lipid intermediates. The resulting downregulation of the insulin signaling cascade prevents the translocation of glucose transporter to the plasma membrane and glucose uptake into skeletal muscle, leading to metabolic disorders such as type 2 diabetes. The mechanisms underlining metabolic dysfunction in skeletal muscle include accumulation of intracellular lipid derivatives from elevated plasma FFAs. This paper provides a review of the molecular mechanisms underlying insulin-related signaling pathways after excess accumulation of lipids.
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Pataky MW, Arias EB, Wang H, Zheng X, Cartee GD. Exercise effects on γ3-AMPK activity, phosphorylation of Akt2 and AS160, and insulin-stimulated glucose uptake in insulin-resistant rat skeletal muscle. J Appl Physiol (1985) 2020; 128:410-421. [PMID: 31944891 DOI: 10.1152/japplphysiol.00428.2019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
One exercise session can increase subsequent insulin-stimulated glucose uptake (ISGU) by skeletal muscle. Prior research on healthy muscle suggests that enhanced postexercise ISGU depends on elevated γ3-AMPK activity leading to greater phosphorylation of Akt substrate of 160 kDa (pAS160) on an AMPK-phosphomotif (Ser704). Phosphorylation of AS160Ser704, in turn, may favor greater insulin-stimulated pAS160 on an Akt-phosphomotif (Thr642) that regulates ISGU. Accordingly, we tested if exercise-induced increases in γ3-AMPK activity and pAS160 on key regulatory sites accompany improved ISGU at 3 h postexercise (3hPEX) in insulin-resistant muscle. Rats fed a high-fat diet (HFD; 2-wk) that induces insulin resistance either performed acute swim-exercise (2 h) or were sedentary (SED). SED rats fed a low-fat diet (LFD; 2 wk) served as healthy controls. Isolated epitrochlearis muscles from 3hPEX and SED rats were analyzed for ISGU, pAS160, pAkt2 (Akt-isoform that phosphorylates pAS160Thr642), and γ1-AMPK and γ3-AMPK activity. ISGU was lower in HFD-SED muscles versus LFD-SED, but this decrement was eliminated in the HFD-3hPEX group. γ3-AMPK activity, but not γ1-AMPK activity, was elevated in HFD-3hPEX muscles versus both SED controls. Furthermore, insulin-stimulated pAS160Thr642, pAS160Ser704, and pAkt2Ser474 in HFD-3hPEX muscles were elevated above HFD-SED and equal to values in LFD-SED muscles, but insulin-independent pAS160Ser704 was unaltered at 3hPEX. These results demonstrated, for the first time in an insulin-resistant model, that the postexercise increase in ISGU was accompanied by sustained enhancement of γ3-AMPK activation and greater pAkt2Ser474. Our working hypothesis is that these changes along with enhanced insulin-stimulated pAS160 increase ISGU of insulin-resistant muscles to values equaling insulin-sensitive sedentary controls.NEW & NOTEWORTHY Earlier research focusing on signaling events linked to increased insulin sensitivity in muscle has rarely evaluated insulin resistant muscle after exercise. We assessed insulin resistant muscle after an exercise protocol that improved insulin-stimulated glucose uptake. Prior exercise also amplified several signaling steps expected to favor enhanced insulin-stimulated glucose uptake: increased γ3-AMP-activated protein kinase activity, greater insulin-stimulated Akt2 phosphorylation on Ser474, and elevated insulin-stimulated Akt substrate of 160 kDa phosphorylation on Ser588, Thr642, and Ser704.
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Affiliation(s)
- Mark W Pataky
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, Michigan
| | - Edward B Arias
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, Michigan
| | - Haiyan Wang
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, Michigan
| | - Xiaohua Zheng
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, Michigan
| | - Gregory D Cartee
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan, Ann Arbor, Michigan.,Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan.,Institute of Gerontology, University of Michigan, Ann Arbor, Michigan
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11
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Stafeev IS, Sklyanik IA, Yah'yaev KA, Shestakova EA, Yurasov AV, Karmadonov AV, Chibalin AV, Yu Menshikov M, Vorotnikov AV, Parfyonova YV, Shestakova MV. Low AS160 and high SGK basal phosphorylation associates with impaired incretin profile and type 2 diabetes in adipose tissue of obese patients. Diabetes Res Clin Pract 2019; 158:107928. [PMID: 31734225 DOI: 10.1016/j.diabres.2019.107928] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 10/18/2019] [Accepted: 11/12/2019] [Indexed: 01/28/2023]
Abstract
OBJECTIVE To compare basal insulin and mTOR signaling in subcutaneous fat of obese T2DM vs. obese subjects with normal glucose tolerance (NGT), and correlate it with clinical parameters of carbohydrate metabolism and incretin secretion profiles. METHODS Recruited were 22 patients with long (>10 years) and morbid (BMI > 35 kg/m2) obesity, 12 of which had NGT and 10 had T2DM. Hyperinsulinemic-euglycemic clamp test and HOMA-IR were used to measure insulin resistance. Blood samples taken at 0, 30 and 120 min of food load test were used to assess incretin profile, insulin and glucose levels. Amount of total and visceral fat was determined by bioelectrical impedance analysis. Subcutaneous fat biopsies were obtained during bariatric surgery for all patients and analyzed by western blots. RESULTS As assessed by western blots of insulin receptor substrate (IRS), Akt, Raptor, Rictor, mTOR and S6K1, the basal insulin signaling and mTORC activities were comparable in NGT and T2DM groups, whereas phosphorylation of AS160 was significantly lower and that of serum and glucocorticoid-induced kinase (SGK) was significantly higher in T2DM group. Various correlations were found between the degree of insulin resistance and amount of visceral fat, changes in incretin profile, glucose metabolic parameters and phosphorylation level of AS160, incretin secretion profile and phosphorylated levels of AS160 or SGK1. CONCLUSION Altered phosphorylation of AS160 and SGK1 is associated with obese T2DM phenotype.
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Affiliation(s)
- Iurii S Stafeev
- National Medical Research Center for Cardiology, Moscow, Russia; Endocrinology Research Centre, Moscow, Russia.
| | | | | | | | | | | | - Alexander V Chibalin
- Integrative Physiology, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden; National Research Tomsk State University, Tomsk, Russia
| | | | | | - Yelena V Parfyonova
- National Medical Research Center for Cardiology, Moscow, Russia; M.V. Lomonosov Moscow State University, Moscow, Russia
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Li Y, Xiang Q, Yao YH, Li JJ, Wang Y, Li XH. Inactivated AMPK-α2 promotes the progression of diabetic brain damage by Cdk5 phosphorylation at Thr485 site. Biochimie 2019; 168:277-284. [PMID: 31786229 DOI: 10.1016/j.biochi.2019.11.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 11/18/2019] [Indexed: 02/01/2023]
Abstract
Changes in brain energy metabolism in diabetes mellitus, including increased insulin resistance and mitochondrial dysfunction, are critically involved in diabetes-related neurodegeneration, and associate with early cognitive impairment as well. The aim of this study is to detect the specific phosphorylated-Thr485- AMP-activated protein kinase (AMPK-α2), regulated by cyclin-dependent kinase 5 (Cdk5) paly the inhibitory functional role of AMPK-α2, Which is maybe the link to the accelerated diabetic brain damage progression. Here, we used GK rats, the type 2 diabetic animal model for in vivo studies and performed In vitro kinase assay, high glucose treatment, -phosphorylated mutation and protein expression in both HEK-293T and HT-22 cell lines. In vitro, the results show that murine wild-type AMPK-α2 was phosphorylated by Cdk5 at a (S/T)PX(K/H/R) phosphorylation consensus sequence, which was associated with decreased AMPK-α2 activity. Surprisingly, mutation of Thr485 to alanine in AMPK-α2 results in the abolished Cdk5 effects, demonstrating that Thr485-phosphorylation is critical to AMPK-α2 inhibition by Cdk5. In addition, these alterations in AMPK-α2-phosphorylation and -activity induced by Cdk5 is specific at Thr485. Furthermore, in GK rats, the increased phosphorylated- Thr 485 of AMPK-α2 results in the decreased AMPK-α2 activity, which is correlated with the apoptosis of neurons in hippocamps. After high glucose treatment, the decreased survival showed in AMPK-α2T485A HT-22 cells compared to AMPK-α2WT. The down-regulated of p-CREB, SNAP25, synaptophysin as well as synapsin-1were shown in both GK rats and HT-22 cell line. Meanwhile, pre-treated with either the specific Cdk5-inhibitor (roscovitine) or the antidiabetic AMPK-α2-inhibitor (metformin) could restore the alterations in neuronal protein expression. Our results suggest that Cdk5-mediated phosphorylated- Thr485 in AMPK-α2 may be involved in the pathogenesis of diabetic brain damage.
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Affiliation(s)
- Yan Li
- College of Medicine, Jishou University, Hunan Province, PR China
| | - Qiong Xiang
- Institute of Medicine, Medical Research Center, Hunan Engineering Laboratory for Analyse and Drugs Development of Ethnomedicine in Wuling Mountains, Jishou University, Hunan Province, PR China
| | - Yu-Han Yao
- College of Medicine, Jishou University, Hunan Province, PR China
| | - Jing-Jing Li
- College of Medicine, Jishou University, Hunan Province, PR China
| | - Yan Wang
- Pharmacy Department, The First People's Hospital of Foshan, Foshan City, Guang Dong Province, PR China
| | - Xian-Hui Li
- Institute of Medicine, Medical Research Center, Hunan Engineering Laboratory for Analyse and Drugs Development of Ethnomedicine in Wuling Mountains, Jishou University, Hunan Province, PR China.
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13
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Consitt LA, Dudley C, Saxena G. Impact of Endurance and Resistance Training on Skeletal Muscle Glucose Metabolism in Older Adults. Nutrients 2019; 11:nu11112636. [PMID: 31684154 PMCID: PMC6893763 DOI: 10.3390/nu11112636] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 10/14/2019] [Accepted: 10/18/2019] [Indexed: 12/20/2022] Open
Abstract
Aging is associated with insulin resistance and the development of type 2 diabetes. While this process is multifaceted, age-related changes to skeletal muscle are expected to contribute to impaired glucose metabolism. Some of these changes include sarcopenia, impaired insulin signaling, and imbalances in glucose utilization. Endurance and resistance exercise training have been endorsed as interventions to improve glucose tolerance and whole-body insulin sensitivity in the elderly. While both types of exercise generally increase insulin sensitivity in older adults, the metabolic pathways through which this occurs can differ and can be dependent on preexisting conditions including obesity and type 2 diabetes. In this review, we will first highlight age-related changes to skeletal muscle which can contribute to insulin resistance, followed by a comparison of endurance and resistance training adaptations to insulin-stimulated glucose metabolism in older adults.
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Affiliation(s)
- Leslie A Consitt
- Department of Biomedical Sciences, Ohio University, Athens, OH 45701, USA.
- Ohio Musculoskeletal and Neurological Institute, Ohio University, Athens, OH 45701, USA.
- Diabetes Institute, Ohio University, Athens, OH 45701, USA.
| | - Courtney Dudley
- Department of Biological Sciences, Ohio University, Athens, OH 45701, USA.
| | - Gunjan Saxena
- Department of Biomedical Sciences, Ohio University, Athens, OH 45701, USA.
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14
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Wu SH, Xu XY, Sun CB, Wen FF, He S, Gao XQ, Liu YH, Liu L. Expression of PHLPP2 correlates with clinicopathologic characteristics and prognosis in colorectal cancer. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2019; 12:2909-2919. [PMID: 31934127 PMCID: PMC6949717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 05/24/2019] [Indexed: 06/10/2023]
Abstract
PH domain leucine-rich repeat protein phosphatase 2 (PHLPP2) belongs to the phosphokinase family, that has been reported to play an important role in several cancers. However, the expression of PHLPP2 and its correlation with clinicopathologic characteristics in colorectal cancer (CRC) have yet to be determined. The aim of this study is to investigate the expression of PHLPP2 and explore its role in CRC. The expression of PHLPP2, PTEN, PI3KCA, and PI3KCB in 130 cases of CRC and normal tissues was assessed by immunohistochemistry. In addition, the expression of PHLPP2, PTEN, PI3KCA, and PI3KCB in 32 pairs of CRC tissues and their corresponding normal tissues was determined by RT-PCR and western blotting, respectively. PHLPP2 expression in CRC was significantly lower than that of normal tissues. However, PHLPP2 mRNA shows no significant difference between CRC and normal tissue. PTEN expression in left colorectal cancer (LCC) was absent, while PI3KCA and PI3KCB in right colorectal cancer (RCC) were significantly higher than those in LCC. PHLPP2 was negatively correlated with p-Akt1 in CRC. The expression of p-Akt1 in PHLPP2 (+)/PTEN (+) in CRC tissues was significantly lower than that in other groups. PHLPP2 expression was correlated with differentiation, invasion, and lymph node metastasis. Kaplan-Meier analysis and multivariate analysis reveal that PHLPP2 is closely related to prognosis; more importantly, it is an independent prognostic factor for CRC. In conclusion, PHLPP2 may play a major role in the development, metastasis, and prognosis of CRC.
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Affiliation(s)
| | | | - Chen-Bo Sun
- Department of Pathology, Binzhou Medical University HospitalBinzhou, Shandong Province, China
| | - Fei-Fei Wen
- Department of Pathology, Binzhou Medical University HospitalBinzhou, Shandong Province, China
| | - Shuang He
- Department of Pathology, Binzhou Medical University HospitalBinzhou, Shandong Province, China
| | - Xiang-Qian Gao
- Department of Pathology, Binzhou Medical University HospitalBinzhou, Shandong Province, China
| | - Yuan-Hang Liu
- Department of Pathology, Binzhou Medical University HospitalBinzhou, Shandong Province, China
| | - Liu Liu
- Department of Pathology, Binzhou Medical University HospitalBinzhou, Shandong Province, China
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15
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Wang H, Arias EB, Pataky MW, Goodyear LJ, Cartee GD. Postexercise improvement in glucose uptake occurs concomitant with greater γ3-AMPK activation and AS160 phosphorylation in rat skeletal muscle. Am J Physiol Endocrinol Metab 2018; 315:E859-E871. [PMID: 30130149 PMCID: PMC6293165 DOI: 10.1152/ajpendo.00020.2018] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
A single exercise session can increase insulin-stimulated glucose uptake (GU) by skeletal muscle, concomitant with greater Akt substrate of 160 kDa (AS160) phosphorylation on Akt-phosphosites (Thr642 and Ser588) that regulate insulin-stimulated GU. Recent research using mouse skeletal muscle suggested that ex vivo 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) or electrically stimulated contractile activity-inducing increased γ3-AMPK activity and AS160 phosphorylation on a consensus AMPK-motif (Ser704) resulted in greater AS160 Thr642 phosphorylation and GU by insulin-stimulated muscle. Our primary goal was to determine whether in vivo exercise that increases insulin-stimulated GU in rat skeletal muscle would also increase γ3-AMPK activity and AS160 site-selective phosphorylation (Ser588, Thr642, and Ser704) immediately postexercise (IPEX) and/or 3 h postexercise (3hPEX). Epitrochlearis muscles isolated from sedentary and exercised (2-h swim exercise; studied IPEX and 3hPEX) rats were incubated with 2-deoxyglucose to determine GU (without insulin at IPEX; without or with insulin at 3hPEX). Muscles were also assessed for γ1-AMPK activity, γ3-AMPK activity, phosphorylated AMPK (pAMPK), and phosphorylated AS160 (pAS160). IPEX versus sedentary had greater γ3-AMPK activity, pAS160 (Ser588, Thr642, Ser704), and GU with unaltered γ1-AMPK activity. 3hPEX versus sedentary had greater γ3-AMPK activity, pAS160 Ser704, and GU with or without insulin; greater pAS160 Thr642 only with insulin; and unaltered γ1-AMPK activity. These results using an in vivo exercise protocol that increased insulin-stimulated GU in rat skeletal muscle are consistent with the hypothesis that in vivo exercise-induced enhancement of γ3-AMPK activation and AS160 Ser704 IPEX and 3hPEX are important for greater pAS160 Thr642 and enhanced insulin-stimulated GU by skeletal muscle.
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Affiliation(s)
- Haiyan Wang
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan , Ann Arbor, Michigan
| | - Edward B Arias
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan , Ann Arbor, Michigan
| | - Mark W Pataky
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan , Ann Arbor, Michigan
| | - Laurie J Goodyear
- Department of Medicine, Brigham and Women's Hospital, Harvard Medical School , Boston, Massachusetts
| | - Gregory D Cartee
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan , Ann Arbor, Michigan
- Department of Molecular and Integrative Physiology, University of Michigan , Ann Arbor, Michigan
- Institute of Gerontology, University of Michigan , Ann Arbor, Michigan
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16
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Arias EB, Wang H, Cartee GD. Akt substrate of 160 kDa dephosphorylation rate is reduced in insulin-stimulated rat skeletal muscle after acute exercise. Physiol Res 2017; 67:143-147. [PMID: 29137480 DOI: 10.33549/physiolres.933591] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Because greater Akt substrate of 160 kDa (AS160) phosphorylation has been reported in insulin-stimulated skeletal muscles without improved Akt activation several hours post-exercise, we hypothesized that prior exercise would result in attenuated AS160 dephosphorylation in insulin-stimulated rat skeletal muscle. Epitrochlearis muscles were isolated from rats that were sedentary (SED) or exercised 3 h earlier (3 h post-exercise; 3hPEX). Paired muscles were incubated with [(3)H]-2-deoxyglucose (2-DG) without insulin or with insulin. Lysates from other insulin-stimulated muscles from SED or 3hPEX rats were evaluated using AS160(Thr642) and AS160(Ser588) dephosphorylation assays. Prior exercise led to greater 2-DG uptake concomitant with greater AS160(Thr642) phosphorylation and a non-significant trend (P=0.087) for greater AS160(Ser588). Prior exercise also reduced AS160(Thr642) and AS160(Ser588) dephosphorylation rates. These results support the idea that attenuated AS160 dephosphorylation may favor greater AS160 phosphorylation post-exercise.
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Affiliation(s)
- E B Arias
- School of Kinesiology, University of Michigan, Ann Arbor, MI, USA.
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