Impairment of Glucose Uptake Induced by Elevated Intracellular Ca<sup>2+</sup> in Hippocampal Neurons of Malignant Hyperthermia-Susceptible Mice

Malignant hyperthermia (MH) is a genetic disorder triggered by depolarizing muscle relaxants or halogenated inhalational anesthetics in genetically predisposed individuals who have a chronic elevated intracellular Ca<sup>2+</sup> concentration ([Ca<sup>2+</sup>]<sub>i&l...

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Main Authors: Arkady Uryash, Alfredo Mijares, Jose A. Adams, Jose R. Lopez
Format: Article
Language:English
Published: MDPI AG 2024-11-01
Series:Cells
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Online Access:https://www.mdpi.com/2073-4409/13/22/1888
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author Arkady Uryash
Alfredo Mijares
Jose A. Adams
Jose R. Lopez
author_facet Arkady Uryash
Alfredo Mijares
Jose A. Adams
Jose R. Lopez
author_sort Arkady Uryash
collection DOAJ
description Malignant hyperthermia (MH) is a genetic disorder triggered by depolarizing muscle relaxants or halogenated inhalational anesthetics in genetically predisposed individuals who have a chronic elevated intracellular Ca<sup>2+</sup> concentration ([Ca<sup>2+</sup>]<sub>i</sub>) in their muscle cells. We have reported that the muscle dysregulation of [Ca<sup>2+</sup>]<sub>i</sub> impairs glucose uptake, leading to the development of insulin resistance in two rodent experimental models. In this study, we simultaneously measured the [Ca<sup>2+</sup>]<sub>i</sub> and glucose uptake in single enzymatically isolated hippocampal pyramidal neurons from wild-type (WT) and MH-R163C mice. The [Ca<sup>2+</sup>]<sub>i</sub> was recorded using a Ca<sup>2+</sup>-selective microelectrode, and the glucose uptake was assessed utilizing the fluorescent glucose analog 2-NBDG. The MH-R163C hippocampal neurons exhibited elevated [Ca<sup>2+</sup>]<sub>i</sub> and impaired insulin-dependent glucose uptake compared with the WT neurons. Additionally, exposure to isoflurane exacerbated these deficiencies in the MH-R163C neurons, while the WT neurons remained unaffected. Lowering [Ca<sup>2+</sup>]<sub>i</sub> using a Ca<sup>2+</sup>-free solution, SAR7334, or dantrolene increased the glucose uptake in the MH-R163C neurons without significantly affecting the WT neurons. However, further reduction of the [Ca<sup>2+</sup>]<sub>i</sub> below the physiological level using BAPTA decreased the insulin-dependent glucose uptake in both genotypes. Furthermore, the homogenates of the MH-R163C hippocampal neurons showed an altered protein expression of the PI3K/Akt signaling pathway and GLUT4 compared with the WT mice. Our study demonstrated that the chronic elevation of [Ca<sup>2+</sup>]<sub>i</sub> was sufficient to compromise the insulin-dependent glucose uptake in the MH-R163C hippocampal neurons. Moreover, reducing the [Ca<sup>2+</sup>]<sub>i</sub> within a specific range (100–130 nM) could reverse insulin resistance, a hallmark of type 2 diabetes mellitus (T2D).
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spelling doaj-art-006c40c06ec04ec2815dca196b82af312024-11-26T17:56:58ZengMDPI AGCells2073-44092024-11-011322188810.3390/cells13221888Impairment of Glucose Uptake Induced by Elevated Intracellular Ca<sup>2+</sup> in Hippocampal Neurons of Malignant Hyperthermia-Susceptible MiceArkady Uryash0Alfredo Mijares1Jose A. Adams2Jose R. Lopez3Division of Neonatology, Mount Sinai Medical Center, Miami, FL 33140, USACentro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas, Caracas 1020-A, VenezuelaDivision of Neonatology, Mount Sinai Medical Center, Miami, FL 33140, USADepartment of Research, Mount Sinai Medical Center, Miami, FL 33140, USAMalignant hyperthermia (MH) is a genetic disorder triggered by depolarizing muscle relaxants or halogenated inhalational anesthetics in genetically predisposed individuals who have a chronic elevated intracellular Ca<sup>2+</sup> concentration ([Ca<sup>2+</sup>]<sub>i</sub>) in their muscle cells. We have reported that the muscle dysregulation of [Ca<sup>2+</sup>]<sub>i</sub> impairs glucose uptake, leading to the development of insulin resistance in two rodent experimental models. In this study, we simultaneously measured the [Ca<sup>2+</sup>]<sub>i</sub> and glucose uptake in single enzymatically isolated hippocampal pyramidal neurons from wild-type (WT) and MH-R163C mice. The [Ca<sup>2+</sup>]<sub>i</sub> was recorded using a Ca<sup>2+</sup>-selective microelectrode, and the glucose uptake was assessed utilizing the fluorescent glucose analog 2-NBDG. The MH-R163C hippocampal neurons exhibited elevated [Ca<sup>2+</sup>]<sub>i</sub> and impaired insulin-dependent glucose uptake compared with the WT neurons. Additionally, exposure to isoflurane exacerbated these deficiencies in the MH-R163C neurons, while the WT neurons remained unaffected. Lowering [Ca<sup>2+</sup>]<sub>i</sub> using a Ca<sup>2+</sup>-free solution, SAR7334, or dantrolene increased the glucose uptake in the MH-R163C neurons without significantly affecting the WT neurons. However, further reduction of the [Ca<sup>2+</sup>]<sub>i</sub> below the physiological level using BAPTA decreased the insulin-dependent glucose uptake in both genotypes. Furthermore, the homogenates of the MH-R163C hippocampal neurons showed an altered protein expression of the PI3K/Akt signaling pathway and GLUT4 compared with the WT mice. Our study demonstrated that the chronic elevation of [Ca<sup>2+</sup>]<sub>i</sub> was sufficient to compromise the insulin-dependent glucose uptake in the MH-R163C hippocampal neurons. Moreover, reducing the [Ca<sup>2+</sup>]<sub>i</sub> within a specific range (100–130 nM) could reverse insulin resistance, a hallmark of type 2 diabetes mellitus (T2D).https://www.mdpi.com/2073-4409/13/22/1888intracellular Ca<sup>2+</sup>glucosehippocampal neuronsinsulin resistancedantroleneSAR7334
spellingShingle Arkady Uryash
Alfredo Mijares
Jose A. Adams
Jose R. Lopez
Impairment of Glucose Uptake Induced by Elevated Intracellular Ca<sup>2+</sup> in Hippocampal Neurons of Malignant Hyperthermia-Susceptible Mice
Cells
intracellular Ca<sup>2+</sup>
glucose
hippocampal neurons
insulin resistance
dantrolene
SAR7334
title Impairment of Glucose Uptake Induced by Elevated Intracellular Ca<sup>2+</sup> in Hippocampal Neurons of Malignant Hyperthermia-Susceptible Mice
title_full Impairment of Glucose Uptake Induced by Elevated Intracellular Ca<sup>2+</sup> in Hippocampal Neurons of Malignant Hyperthermia-Susceptible Mice
title_fullStr Impairment of Glucose Uptake Induced by Elevated Intracellular Ca<sup>2+</sup> in Hippocampal Neurons of Malignant Hyperthermia-Susceptible Mice
title_full_unstemmed Impairment of Glucose Uptake Induced by Elevated Intracellular Ca<sup>2+</sup> in Hippocampal Neurons of Malignant Hyperthermia-Susceptible Mice
title_short Impairment of Glucose Uptake Induced by Elevated Intracellular Ca<sup>2+</sup> in Hippocampal Neurons of Malignant Hyperthermia-Susceptible Mice
title_sort impairment of glucose uptake induced by elevated intracellular ca sup 2 sup in hippocampal neurons of malignant hyperthermia susceptible mice
topic intracellular Ca<sup>2+</sup>
glucose
hippocampal neurons
insulin resistance
dantrolene
SAR7334
url https://www.mdpi.com/2073-4409/13/22/1888
work_keys_str_mv AT arkadyuryash impairmentofglucoseuptakeinducedbyelevatedintracellularcasup2supinhippocampalneuronsofmalignanthyperthermiasusceptiblemice
AT alfredomijares impairmentofglucoseuptakeinducedbyelevatedintracellularcasup2supinhippocampalneuronsofmalignanthyperthermiasusceptiblemice
AT joseaadams impairmentofglucoseuptakeinducedbyelevatedintracellularcasup2supinhippocampalneuronsofmalignanthyperthermiasusceptiblemice
AT joserlopez impairmentofglucoseuptakeinducedbyelevatedintracellularcasup2supinhippocampalneuronsofmalignanthyperthermiasusceptiblemice