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Modifications of myofilament protein phosphorylation and function in response to cardiac arrest induced in a swine model

Cardiac arrest is a prevalent condition with a poor prognosis, attributable in part to persistent myocardial dysfunction following resuscitation. The molecular basis of this dysfunction remains unclear. We induced cardiac arrest in a porcine model of acute sudden death and assessed the impact of isc...

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Autores principales: Woodward, Mike, Previs, Michael J., Mader, Timothy J., Debold, Edward P.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4503891/
https://www.ncbi.nlm.nih.gov/pubmed/26236240
http://dx.doi.org/10.3389/fphys.2015.00199
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author Woodward, Mike
Previs, Michael J.
Mader, Timothy J.
Debold, Edward P.
author_facet Woodward, Mike
Previs, Michael J.
Mader, Timothy J.
Debold, Edward P.
author_sort Woodward, Mike
collection PubMed
description Cardiac arrest is a prevalent condition with a poor prognosis, attributable in part to persistent myocardial dysfunction following resuscitation. The molecular basis of this dysfunction remains unclear. We induced cardiac arrest in a porcine model of acute sudden death and assessed the impact of ischemia and reperfusion on the molecular function of isolated cardiac contractile proteins. Cardiac arrest was electrically induced, left untreated for 12 min, and followed by a resuscitation protocol. With successful resuscitations, the heart was reperfused for 2 h (IR2) and the muscle harvested. In failed resuscitations, tissue samples were taken following the failed efforts (IDNR). Actin filament velocity, using myosin isolated from IR2 or IDNR cardiac tissue, was nearly identical to myosin from the control tissue in a motility assay. However, both maximal velocity (25% faster than control) and calcium sensitivity (pCa(50) 6.57 ± 0.04 IDNR vs. 6.34 ± 0.07 control) were significantly (p < 0.05) enhanced using native thin filaments (actin+troponin+tropomyosin) from IDNR samples, suggesting that the enhanced velocity is mediated through an alteration in muscle regulatory proteins (troponin+tropomyosin). Mass spectrometry analysis showed that only samples from the IR2 had an increase in total phosphorylation levels of troponin (Tn) and tropomyosin (Tm), but both IR2 and IDNR samples demonstrated a significant shift from mono-phosphorylated to bis-phosphorylated forms of the inhibitory subunit of Tn (TnI) compared to control. This suggests that the shift to bis-phosphorylation of TnI is associated with the enhanced function in IDNR, but this effect may be attenuated when phosphorylation of Tm is increased in tandem, as observed for IR2. There are likely many other molecular changes induced following cardiac arrest, but to our knowledge, these data provide the first evidence that this form cardiac arrest can alter the in vitro function of the cardiac contractile proteins.
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spelling pubmed-45038912015-07-31 Modifications of myofilament protein phosphorylation and function in response to cardiac arrest induced in a swine model Woodward, Mike Previs, Michael J. Mader, Timothy J. Debold, Edward P. Front Physiol Physiology Cardiac arrest is a prevalent condition with a poor prognosis, attributable in part to persistent myocardial dysfunction following resuscitation. The molecular basis of this dysfunction remains unclear. We induced cardiac arrest in a porcine model of acute sudden death and assessed the impact of ischemia and reperfusion on the molecular function of isolated cardiac contractile proteins. Cardiac arrest was electrically induced, left untreated for 12 min, and followed by a resuscitation protocol. With successful resuscitations, the heart was reperfused for 2 h (IR2) and the muscle harvested. In failed resuscitations, tissue samples were taken following the failed efforts (IDNR). Actin filament velocity, using myosin isolated from IR2 or IDNR cardiac tissue, was nearly identical to myosin from the control tissue in a motility assay. However, both maximal velocity (25% faster than control) and calcium sensitivity (pCa(50) 6.57 ± 0.04 IDNR vs. 6.34 ± 0.07 control) were significantly (p < 0.05) enhanced using native thin filaments (actin+troponin+tropomyosin) from IDNR samples, suggesting that the enhanced velocity is mediated through an alteration in muscle regulatory proteins (troponin+tropomyosin). Mass spectrometry analysis showed that only samples from the IR2 had an increase in total phosphorylation levels of troponin (Tn) and tropomyosin (Tm), but both IR2 and IDNR samples demonstrated a significant shift from mono-phosphorylated to bis-phosphorylated forms of the inhibitory subunit of Tn (TnI) compared to control. This suggests that the shift to bis-phosphorylation of TnI is associated with the enhanced function in IDNR, but this effect may be attenuated when phosphorylation of Tm is increased in tandem, as observed for IR2. There are likely many other molecular changes induced following cardiac arrest, but to our knowledge, these data provide the first evidence that this form cardiac arrest can alter the in vitro function of the cardiac contractile proteins. Frontiers Media S.A. 2015-07-16 /pmc/articles/PMC4503891/ /pubmed/26236240 http://dx.doi.org/10.3389/fphys.2015.00199 Text en Copyright © 2015 Woodward, Previs, Mader and Debold. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Physiology
Woodward, Mike
Previs, Michael J.
Mader, Timothy J.
Debold, Edward P.
Modifications of myofilament protein phosphorylation and function in response to cardiac arrest induced in a swine model
title Modifications of myofilament protein phosphorylation and function in response to cardiac arrest induced in a swine model
title_full Modifications of myofilament protein phosphorylation and function in response to cardiac arrest induced in a swine model
title_fullStr Modifications of myofilament protein phosphorylation and function in response to cardiac arrest induced in a swine model
title_full_unstemmed Modifications of myofilament protein phosphorylation and function in response to cardiac arrest induced in a swine model
title_short Modifications of myofilament protein phosphorylation and function in response to cardiac arrest induced in a swine model
title_sort modifications of myofilament protein phosphorylation and function in response to cardiac arrest induced in a swine model
topic Physiology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4503891/
https://www.ncbi.nlm.nih.gov/pubmed/26236240
http://dx.doi.org/10.3389/fphys.2015.00199
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