Anomalous K_v7 channel activity in human malignant hyperthermia syndrome unmasks a key role for H₂S and persulfidation in skeletal muscle

Abstract

Background and Purpose Human malignant hyperthermia (MH) syndrome is induced by volatile anaesthetics and involves increased levels of cystathionine β‐synthase (CBS)‐derived H2S within skeletal muscle. This increase contributes to skeletal muscle hypercontractility. Kv7 channels, expressed in skeletal muscle, may be a molecular target for H2S. Here, we have investigated the role of Kv7 channels in MH. Experimental Approach Skeletal muscle biopsies were obtained from MH‐susceptible (MHS) and MH‐negative (MHN) patients. Immunohistochemistry, RT‐PCR, Western blot, and in vitro contracture test (IVCT) were carried out. Development and characterization of primary human skeletal muscle cells (PHSKMC) and evaluation of cell membrane potential were also performed. The persulfidation state of Kv7 channels and polysulfide levels were measured. Key Results Kv7 channels were similarly expressed in MHN and MHS biopsies. The IVCT revealed an anomalous contractility of MHS biopsies following exposure to the Kv7 channel opener retigabine. Incubation of negative biopsies with NaHS, prior to retigabine addition, led to an MHS‐like positive response. MHS‐derived PHSKMC challenged with retigabine showed a paradoxical depolarizing effect, compared with the canonical hyperpolarizing effect. CBS expression and activity were increased in MHS biopsies, resulting in a major polysulfide bioavailability. Persulfidation of Kv7.4 channels was significantly higher in MHS than in MHN biopsies. Conclusions and Implications In skeletal muscle of MHS patients, CBS‐derived H2S induced persulfidation of Kv7 channels. This post‐translational modification switches the hyperpolarizing activity into depolarizing. This mechanism can contribute to the pathological skeletal muscle hypercontractility typical of MH syndrome. Linked Articles This article is part of a themed section on Hydrogen Sulfide in Biology & Medicine. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.4/issuetoc

Hydrogen Sulfide (H2S) and Polysulfide (H2Sn) Signaling: The First 25 Years

“…H 2 S has also been demonstrated to relax vascular smooth muscle via the protein kinase G pathway as an endogenous inhibitor of phosphodiesterase and increases the levels of both cyclic GMP and cyclic AMP [ 48 , 49 ], as well as by activating Kv7 potassium channels [ 50 ]. Kv7 channels are also involved in CBS-derived H 2 S induced human malignant hyperthermia syndrome triggered by volatile inhalation anesthetics in skeletal muscle [ 51 ].…”

GYY4137 and Sodium Hydrogen Sulfide Relaxations Are Inhibited by L-Cysteine and KV7 Channel Blockers in Rat Small Mesenteric Arteries

“…In patch-clamp studies H 2 S gas 30 μM to 1 mM caused activation of K ATP channels in vascular smooth muscle from mesenteric arteries ( Tang et al, 2005 ), and 10 µM NaSH hyperpolarized mesenteric arteries by iberiotoxin-sensitive mechanism also suggesting the involvement BK Ca channels ( Jackson-Weaver et al, 2011 , 2013 ), and NaHS (1 mM) hyperpolarized rat aorta and directly activated K V 7 channels in CHO cells ( Martelli et al, 2013a ). Recent studies have also shown that direct activation of K V 7 channels by H 2 S donors protects against neuropathic pain ( Di Cesare Mannelli et al, 2017 ), and that direct persulfidation of K V 7 channels by H 2 S plays an important role in skeletal muscle hypercontractility in human malignant hyperthermia syndrome ( Vellecco et al, 2020 ). In agreement with studies in resistance arteries, in small mesenteric arteries contracted with the U46619, Na 2 S in the present study induced relaxations sensitive to high extracellular potassium and blockers of both ATP-sensitive, K V 7, and BK Ca channels suggesting involvement of these channels in Na 2 S relaxation, although electrophysiological measurements, e.g., membrane potential measurements or patch-clamp will be required to confirm the activation of K V 7 channels by Na 2 S in this preparation.…”

“…Hydrogen sulfide (H 2 S) is considered an essential signaling molecule in the cardiovascular and nervous systems ( Szabó, 2007 ; Wallace et al, 2018 ) and a variety of pathophysiological changes including cancer, glycometabolic disorders, diabetes, sepsis, and human malignt hyperthermia are associated with altered endogenous levels of H 2 S ( Szabó, 2007 ; Szabo and Papapetropoulos, 2017 ; Vellecco et al, 2020 ). In the cardiovascular system, endogenous H 2 S can lead to both vasodilatation and vasoconstriction ( Li et al, 2015 ; Hedegaard et al, 2016 ; Gheibi et al, 2018 ).…”

Cystathionine gamma‐lyase/H2S signaling facilitates myogenesis under aging and injury condition

“…22 H 2 S induces the S-sulfhydration of Kv7 channel proteins and contributes to skeletal muscle hypercontractility in human malignant hyperthermia syndrome. 43 H 2 S protects diaphragm muscle fibrosis and strengthens diaphragmatic biomechanical properties in streptozotocin-induced diabetic rats. 44 H 2 S also alleviates the injury of skeletal muscle in ischemia-reperfusion rats, improves muscle functions in high-fat-diet-fed mice, and increases muscle mass in db/db diabetic mice.…”