Metformin Increases Protein Phosphatase 2A Activity in Primary Human Skeletal Muscle Cells Derived from Lean Healthy Participants

Context. Skeletal muscle insulin resistance is one of the primary contributors of type 2 diabetes (T2D). Metformin is the first-line drug for the treatment of T2D. The primary effects of metformin include decreasing glucose production in the liver and decreasing insulin resistance in the skeletal mu...

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Main Authors: Aktham Mestareehi, Xiangmin Zhang, Berhane Seyoum, Zaher Msallaty, Abdullah Mallisho, Kyle Jon Burghardt, Anjaneyulu Kowluru, Zhengping Yi
Format: Article
Language:English
Published: Wiley 2021-01-01
Series:Journal of Diabetes Research
Online Access:http://dx.doi.org/10.1155/2021/9979234
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author Aktham Mestareehi
Xiangmin Zhang
Berhane Seyoum
Zaher Msallaty
Abdullah Mallisho
Kyle Jon Burghardt
Anjaneyulu Kowluru
Zhengping Yi
author_facet Aktham Mestareehi
Xiangmin Zhang
Berhane Seyoum
Zaher Msallaty
Abdullah Mallisho
Kyle Jon Burghardt
Anjaneyulu Kowluru
Zhengping Yi
author_sort Aktham Mestareehi
collection DOAJ
description Context. Skeletal muscle insulin resistance is one of the primary contributors of type 2 diabetes (T2D). Metformin is the first-line drug for the treatment of T2D. The primary effects of metformin include decreasing glucose production in the liver and decreasing insulin resistance in the skeletal muscle. However, the molecular mechanism of metformin’s action in skeletal muscle is not well understood. Protein phosphatase 2A (PP2A), a major serine/threonine protein phosphatase, plays a pivotal role in cellular processes, such as signal transduction, cell proliferation, and apoptosis, and acts through dephosphorylating key signaling molecules such as AKT and AMPK. However, whether PP2A plays a role in metformin-induced insulin sensitivity improvement in human skeletal muscle cells remains to be elucidated. Objective. To investigate if PP2A plays a role in metformin-induced insulin sensitivity improvement in human skeletal muscle cells. Participants. Eight lean insulin-sensitive nondiabetic participants (4 females and 4 males; age: 21.0±1.0 years; BMI: 22.0±0.7 kg/m2; 2-hour OGTT: 97.0±6.0 mg/dl; HbA1c: 5.3±0.1%; fasting plasma glucose: 87.0±2.0 mg/dl; M value; 11.0±1.0 mg/kgBW/min). Design. A hyperinsulinemic-euglycemic clamp was performed to assess insulin sensitivity in human subjects, and skeletal muscle biopsy samples were obtained. Primary human skeletal muscle cells (shown to retain metabolic characteristics of donors) were cultured from these muscle biopsies that included 8 lean insulin-sensitive participants. Cultured cells were expanded, differentiated into myotubes, and treated with 50 μM metformin for 24 hours before harvesting. PP2Ac activity was measured by a phosphatase activity assay kit (Millipore) according to the manufacturer’s protocol. Results. The results indicated that metformin significantly increased the activity of PP2A in the myotubes for all 8 lean insulin-sensitive nondiabetic participants, and the average fold increase is 1.54±0.11 (P<0.001). Conclusions. These results provided the first evidence that metformin can activate PP2A in human skeletal muscle cells derived from lean healthy insulin-sensitive participants and may help to understand metformin’s action in skeletal muscle in humans.
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issn 2314-6745
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publishDate 2021-01-01
publisher Wiley
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series Journal of Diabetes Research
spelling doaj-art-911aea2ca4744002ac182ccfe226cea72025-02-03T05:45:19ZengWileyJournal of Diabetes Research2314-67452314-67532021-01-01202110.1155/2021/99792349979234Metformin Increases Protein Phosphatase 2A Activity in Primary Human Skeletal Muscle Cells Derived from Lean Healthy ParticipantsAktham Mestareehi0Xiangmin Zhang1Berhane Seyoum2Zaher Msallaty3Abdullah Mallisho4Kyle Jon Burghardt5Anjaneyulu Kowluru6Zhengping Yi7Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48201, USADepartment of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48201, USADivision of Endocrinology, Wayne State University School of Medicine, Wayne State University, Detroit, MI 48201, USADivision of Endocrinology, Wayne State University School of Medicine, Wayne State University, Detroit, MI 48201, USADivision of Endocrinology, Wayne State University School of Medicine, Wayne State University, Detroit, MI 48201, USADepartment of Pharmacy Practice, Eugene Applebaum College of Pharmacy/Health Sciences, Wayne State University, Detroit, MI, USADepartment of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48201, USADepartment of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48201, USAContext. Skeletal muscle insulin resistance is one of the primary contributors of type 2 diabetes (T2D). Metformin is the first-line drug for the treatment of T2D. The primary effects of metformin include decreasing glucose production in the liver and decreasing insulin resistance in the skeletal muscle. However, the molecular mechanism of metformin’s action in skeletal muscle is not well understood. Protein phosphatase 2A (PP2A), a major serine/threonine protein phosphatase, plays a pivotal role in cellular processes, such as signal transduction, cell proliferation, and apoptosis, and acts through dephosphorylating key signaling molecules such as AKT and AMPK. However, whether PP2A plays a role in metformin-induced insulin sensitivity improvement in human skeletal muscle cells remains to be elucidated. Objective. To investigate if PP2A plays a role in metformin-induced insulin sensitivity improvement in human skeletal muscle cells. Participants. Eight lean insulin-sensitive nondiabetic participants (4 females and 4 males; age: 21.0±1.0 years; BMI: 22.0±0.7 kg/m2; 2-hour OGTT: 97.0±6.0 mg/dl; HbA1c: 5.3±0.1%; fasting plasma glucose: 87.0±2.0 mg/dl; M value; 11.0±1.0 mg/kgBW/min). Design. A hyperinsulinemic-euglycemic clamp was performed to assess insulin sensitivity in human subjects, and skeletal muscle biopsy samples were obtained. Primary human skeletal muscle cells (shown to retain metabolic characteristics of donors) were cultured from these muscle biopsies that included 8 lean insulin-sensitive participants. Cultured cells were expanded, differentiated into myotubes, and treated with 50 μM metformin for 24 hours before harvesting. PP2Ac activity was measured by a phosphatase activity assay kit (Millipore) according to the manufacturer’s protocol. Results. The results indicated that metformin significantly increased the activity of PP2A in the myotubes for all 8 lean insulin-sensitive nondiabetic participants, and the average fold increase is 1.54±0.11 (P<0.001). Conclusions. These results provided the first evidence that metformin can activate PP2A in human skeletal muscle cells derived from lean healthy insulin-sensitive participants and may help to understand metformin’s action in skeletal muscle in humans.http://dx.doi.org/10.1155/2021/9979234
spellingShingle Aktham Mestareehi
Xiangmin Zhang
Berhane Seyoum
Zaher Msallaty
Abdullah Mallisho
Kyle Jon Burghardt
Anjaneyulu Kowluru
Zhengping Yi
Metformin Increases Protein Phosphatase 2A Activity in Primary Human Skeletal Muscle Cells Derived from Lean Healthy Participants
Journal of Diabetes Research
title Metformin Increases Protein Phosphatase 2A Activity in Primary Human Skeletal Muscle Cells Derived from Lean Healthy Participants
title_full Metformin Increases Protein Phosphatase 2A Activity in Primary Human Skeletal Muscle Cells Derived from Lean Healthy Participants
title_fullStr Metformin Increases Protein Phosphatase 2A Activity in Primary Human Skeletal Muscle Cells Derived from Lean Healthy Participants
title_full_unstemmed Metformin Increases Protein Phosphatase 2A Activity in Primary Human Skeletal Muscle Cells Derived from Lean Healthy Participants
title_short Metformin Increases Protein Phosphatase 2A Activity in Primary Human Skeletal Muscle Cells Derived from Lean Healthy Participants
title_sort metformin increases protein phosphatase 2a activity in primary human skeletal muscle cells derived from lean healthy participants
url http://dx.doi.org/10.1155/2021/9979234
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