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Khajavi N, Riçku K, Schreier PCF, Gentz T, Beyerle P, Cruz E, Breit A, Reinach PS, Gudermann T. Chronic Mg 2+ Deficiency Does Not Impair Insulin Secretion in Mice. Cells 2023; 12:1790. [PMID: 37443824 PMCID: PMC10340716 DOI: 10.3390/cells12131790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 06/28/2023] [Accepted: 07/03/2023] [Indexed: 07/15/2023] Open
Abstract
Magnesium is an essential mediator of a vast number of critical enzymatic cellular reactions in the human body. Some clinical epidemiological studies suggest that hypomagnesemia accounts for declines in insulin secretion in patients with type 2 diabetes (T2D); however, the results of various experimental studies do not support this notion. To address this discrepancy, we assessed the short- and long-term effects of hypomagnesemia on β-cell function and insulin secretion in primary mouse islets of Langerhans and in a mouse model of hypomagnesemia known as Trpm6Δ17 /fl;Villin1-Cre mice. We found that lowering the extracellular Mg2+ concentration from 1.2 mM to either 0.6 or 0.1 mM remarkably increased glucose-induced insulin secretion (GIIS) in primary islets isolated from C57BL/6 mice. Similarly, both the plasma insulin levels and GIIS rose in isolated islets of Trpm6Δ17 /fl;Villin1-Cre mice. We attribute these rises to augmented increases in intracellular Ca2+ oscillations in pancreatic β-cells. However, the glycemic metabolic profile was not impaired in Trpm6Δ17 /fl;Villin1-Cre mice, suggesting that chronic hypomagnesemia does not lead to insulin resistance. Collectively, the results of this study suggest that neither acute nor chronic Mg2+ deficiency suppresses glucose-induced rises in insulin secretion. Even though hypomagnesemia can be symptomatic of T2D, such deficiency may not account for declines in insulin release in this disease.
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Affiliation(s)
- Noushafarin Khajavi
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, 80539 Munich, Germany; (K.R.); (P.C.F.S.); (T.G.); (P.B.); (E.C.); (A.B.)
| | - Klea Riçku
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, 80539 Munich, Germany; (K.R.); (P.C.F.S.); (T.G.); (P.B.); (E.C.); (A.B.)
| | - Pascale C. F. Schreier
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, 80539 Munich, Germany; (K.R.); (P.C.F.S.); (T.G.); (P.B.); (E.C.); (A.B.)
| | - Tanja Gentz
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, 80539 Munich, Germany; (K.R.); (P.C.F.S.); (T.G.); (P.B.); (E.C.); (A.B.)
| | - Philipp Beyerle
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, 80539 Munich, Germany; (K.R.); (P.C.F.S.); (T.G.); (P.B.); (E.C.); (A.B.)
| | - Emmanuel Cruz
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, 80539 Munich, Germany; (K.R.); (P.C.F.S.); (T.G.); (P.B.); (E.C.); (A.B.)
| | - Andreas Breit
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, 80539 Munich, Germany; (K.R.); (P.C.F.S.); (T.G.); (P.B.); (E.C.); (A.B.)
| | - Peter S. Reinach
- Ophthalmology Department, Wenzhou Medical University, Wenzhou 325015, China;
| | - Thomas Gudermann
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, 80539 Munich, Germany; (K.R.); (P.C.F.S.); (T.G.); (P.B.); (E.C.); (A.B.)
- German Center for Lung Research, 81377 Munich, Germany
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Khajavi N, Beck A, Riçku K, Beyerle P, Jacob K, Syamsul SF, Belkacemi A, Reinach PS, Schreier PC, Salah H, Popp T, Novikoff A, Breit A, Chubanov V, Müller TD, Zierler S, Gudermann T. TRPM7 kinase is required for insulin production and compensatory islet responses during obesity. JCI Insight 2023; 8:163397. [PMID: 36574297 PMCID: PMC9977431 DOI: 10.1172/jci.insight.163397] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 12/21/2022] [Indexed: 12/28/2022] Open
Abstract
Most overweight individuals do not develop diabetes due to compensatory islet responses to restore glucose homeostasis. Therefore, regulatory pathways that promote β cell compensation are potential targets for treatment of diabetes. The transient receptor potential cation channel subfamily M member 7 protein (TRPM7), harboring a cation channel and a serine/threonine kinase, has been implicated in controlling cell growth and proliferation. Here, we report that selective deletion of Trpm7 in β cells disrupted insulin secretion and led to progressive glucose intolerance. We indicate that the diminished insulinotropic response in β cell-specific Trpm7-knockout mice was caused by decreased insulin production because of impaired enzymatic activity of this protein. Accordingly, high-fat-fed mice with a genetic loss of TRPM7 kinase activity displayed a marked glucose intolerance accompanied by hyperglycemia. These detrimental glucoregulatory effects were engendered by reduced compensatory β cell responses because of mitigated protein kinase B (AKT)/ERK signaling. Collectively, our data identify TRPM7 kinase as a potentially novel regulator of insulin synthesis, β cell dynamics, and glucose homeostasis under obesogenic diet.
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Affiliation(s)
- Noushafarin Khajavi
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, Munich, Germany
| | - Andreas Beck
- Institute of Experimental and Clinical Pharmacology and Toxicology, Saarland University, Homburg, Germany
| | - Klea Riçku
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, Munich, Germany
| | - Philipp Beyerle
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, Munich, Germany
| | - Katharina Jacob
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, Munich, Germany
| | - Sabrina F. Syamsul
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, Munich, Germany
| | - Anouar Belkacemi
- Institute of Experimental and Clinical Pharmacology and Toxicology, Saarland University, Homburg, Germany
| | - Peter S. Reinach
- Wenzhou Medical University, Ophthalmology Department, Wenzhou, China
| | - Pascale C.F. Schreier
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, Munich, Germany
| | - Houssein Salah
- Institute of Experimental and Clinical Pharmacology and Toxicology, Saarland University, Homburg, Germany
| | - Tanja Popp
- Bundeswehr Institute of Radiobiology, Munich, Germany
| | - Aaron Novikoff
- Institute of Diabetes and Obesity, Helmholtz Center Munich, Neuherberg, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Andreas Breit
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, Munich, Germany
| | - Vladimir Chubanov
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, Munich, Germany
| | - Timo D. Müller
- Institute of Diabetes and Obesity, Helmholtz Center Munich, Neuherberg, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Susanna Zierler
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, Munich, Germany.,Institute of Pharmacology, Medical Faculty, Johannes Kepler University Linz, Linz, Austria
| | - Thomas Gudermann
- Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, Munich, Germany.,German Center for Lung Research, Munich, Germany
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