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Heme-Induced Oxidation of Cysteine Groups of Myofilament Proteins Leads to Contractile Dysfunction of Permeabilized Human Skeletal Muscle Fibres.

ABSTRACT: Heme released from red blood cells targets a number of cell components including the cytoskeleton. The purpose of the present study was to determine the impact of free heme (20-300 µM) on human skeletal muscle fibres made available during orthopedic surgery. Isometric force production and oxidative protein modifications were monitored in permeabilized skeletal muscle fibre segments. A single heme exposure (20 µM) to muscle fibres decreased Ca2+-activated maximal (active) force (Fo) by about 50% and evoked an approximately 3-fold increase in Ca2+-independent (passive) force (Fpassive). Oxidation of sulfhydryl (SH) groups was detected in structural proteins (e.g., nebulin, ?-actinin, meromyosin 2) and in contractile proteins (e.g., myosin heavy chain and myosin-binding protein C) as well as in titin in the presence of 300 µM heme. This SH oxidation was not reversed by dithiothreitol (50 mM). Sulfenic acid (SOH) formation was also detected in the structural proteins (nebulin, ?-actinin, meromyosin). Heme effects on SH oxidation and SOH formation were prevented by hemopexin (Hpx) and ?1-microglobulin (A1M). These data suggest that free heme has a significant impact on human skeletal muscle fibres, whereby oxidative alterations in structural and contractile proteins limit contractile function. This may explain and or contribute to the weakness and increase of skeletal muscle stiffness in chronic heart failure, rhabdomyolysis, and other hemolytic diseases. Therefore, therapeutic use of Hpx and A1M supplementation might be effective in preventing heme-induced skeletal muscle alterations.

SUBMITTER: Alvarado G

PROVIDER: S-EPMC7663642 | biostudies-literature | 2020 Oct

REPOSITORIES: biostudies-literature

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Heme-Induced Oxidation of Cysteine Groups of Myofilament Proteins Leads to Contractile Dysfunction of Permeabilized Human Skeletal Muscle Fibres.

Alvarado Gerardo G Tóth Attila A Csősz Éva É Kalló Gergő G Dankó Katalin K Csernátony Zoltán Z Smith Ann A Gram Magnus M Akerström Bo B Édes István I Balla György G Papp Zoltán Z Balla József J

International journal of molecular sciences 20201031 21

Heme released from red blood cells targets a number of cell components including the cytoskeleton. The purpose of the present study was to determine the impact of free heme (20-300 µM) on human skeletal muscle fibres made available during orthopedic surgery. Isometric force production and oxidative protein modifications were monitored in permeabilized skeletal muscle fibre segments. A single heme exposure (20 µM) to muscle fibres decreased Ca<sup>2+</sup>-activated maximal (active) force (F<sub> ...[more]

PMID: 33142923

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Project description:Background The axon guidance cue Slit2 recently has been found to regulate calcium homeostasis and molecular signaling in various stress events in different organs. However, whether Slit2 plays a role in cardiac ischemia-reperfusion (IR) injury has not been reported. Here, we aimed to investigate the role of Slit2 and the underlying mechanisms in cardiac IR injury. Methods Langendorff-perfused isolated hearts from Slit2-overexpressing (Slit2-Tg) mice and their background strain C57BL/6J mice were subjected to 20 min of global ischemia followed by 40 min of reperfusion. Left ventricular function of isolated hearts was monitored. Infarct size of post-IR hearts was determined by staining with 2,3,5-triphenyltetrazolium chloride (TTC) and histological changes of cardiac tissues and cells were determined with hematoxylin-eosin (HE) staining and transmission electron microscopy. Transcriptomic analysis was used to predict the biological processes and signaling pathways affected by Slit2 overexpression in the post-IR myocardium. Pro-Q staining and Western blotting was used to assess the phosphorylation levels of cardiac myofilaments and expression levels of myofilament-associated protein kinase and phosphatases. Results Slit2 overexpression increased post-IR left ventricular developed pressure (LVDP) by 35% and reduced infarct size by 53%, along with decreased myofibrillar disruption, mitochondrial swelling, and mitochondrial cristae dissolution. Slit2 overexpression significantly changed post-IR gene expression profiles. Functional products of these genes include regulation of cation transmembrane transport, cation homeostasis, collagen fibril organization, and regulation of heart rate. And post-IR myocardial KEGG pathways upregulated by Slit2 overexpression include ECM-receptor interaction, PI3K-Akt signaling pathway, and adrenergic signaling. Slit2 overexpression impacted myofilament phosphorylation together with myofilament-associated protein kinase C (PKC) isoforms and protein phosphatases (PPs). IR in C57BL/6J hearts upregulated phosphorylation of cardiac troponin-I (cTnI), which was suppressed by Slit2 overexpression. Myofilament‐associated PKCε, PKCδ, and PP2A were significantly increased post‐IR in C57BL/6J hearts, but in Slit2‐Tg hearts, myofilament‐associated PKCε and PP2A were increased and PKCδ was suppressed. Conclusions Our results demonstrate that Slit2 overexpression protects cardiac function and reduces IR injury, which is associated with Slit2‐induced gene profile shifts. The suppression of MyBP‐C and troponin‐I phosphorylation, and myofilament‐associated PKCδ levels induced by Slit2 overexpression could contribute to the cardioprotection of Slit2 in post-IR myocardium.

Dataset Information

Heme-Induced Oxidation of Cysteine Groups of Myofilament Proteins Leads to Contractile Dysfunction of Permeabilized Human Skeletal Muscle Fibres.

Publications

Heme-Induced Oxidation of Cysteine Groups of Myofilament Proteins Leads to Contractile Dysfunction of Permeabilized Human Skeletal Muscle Fibres.

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