Breakdown and release of myofilament proteins during ischemia and ischemia/reperfusion in rat hearts identification of degradation products and effects on the pCa-force relation

Jennifer E. Van Eyk, Francis Powers, William Law, Catherine Larue, Robert S. Hodges, R. John Solaro

Research output: Contribution to journalArticle

Abstract

Our objective in experiments reported here was to identify myofilament proteins of rat hearts either lost or degraded by cardiac ischemia (15- or 60-minute duration) with and without 45 minutes of reperfusion. We correlated these changes with alterations in myofilament sensitivity to Ca2+ and maximum force generation. Protein degradation and loss were assessed by high- performance liquid chromatography, SDS-PAGE, Western blotting analysis, and amino acid sequencing. Compared with nonischemic control hearts, bundles of skinned fibers from hearts subjected to ischemia alone demonstrated a decrease in maximum force generation and an increase in sensitivity to Ca2+. These changes in function were increased with the duration of the ischemia and with reperfusion. With increasing duration of ischemia, there was an increased loss and degradation of myofibrillar α-actinin and troponin I (TnI) at its C-terminus. α-Actinin and TnI were most susceptible to ischemia, but with 60 minutes of ischemia/reperfusion, there was also degradation of myosin light chain-1 (MLC1) involving a clip of residues 1 to 19. The MLC1 degradation product was detected in the reperfusion effluent (along with troponin T, tropomyosin, and α-actinin) but not in the tissue with 60 minutes of ischemia with no reperfusion. Moreover, with ischemia the following proteins became associated with the myofibrils: GAPDH and proteins of the mitochondrial ATP synthase complex. Our results provide new evidence regarding the mechanism by which ischemia/reperfusion causes myocardial injury and support the hypothesis that an important element in the injury is altered activity and structure of the myofilaments.

Original languageEnglish (US)
Pages (from-to)261-271
Number of pages11
JournalCirculation Research
Volume82
Issue number2
StatePublished - Feb 9 1998
Externally publishedYes

Fingerprint

Myofibrils
Reperfusion
Ischemia
Actinin
Proteins
Myosin Light Chains
Troponin I
Mitochondrial Proton-Translocating ATPases
Myocardial Reperfusion Injury
Tropomyosin
Troponin T
Protein Sequence Analysis
Surgical Instruments
Proteolysis
Polyacrylamide Gel Electrophoresis
Western Blotting
High Pressure Liquid Chromatography
Wounds and Injuries

Keywords

  • α-actinin
  • Myocardial ischemia/reperfusion
  • Myofilament
  • Protein degradation
  • Troponin I

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine

Cite this

Breakdown and release of myofilament proteins during ischemia and ischemia/reperfusion in rat hearts identification of degradation products and effects on the pCa-force relation. / Van Eyk, Jennifer E.; Powers, Francis; Law, William; Larue, Catherine; Hodges, Robert S.; Solaro, R. John.

In: Circulation Research, Vol. 82, No. 2, 09.02.1998, p. 261-271.

Research output: Contribution to journalArticle

Van Eyk, Jennifer E. ; Powers, Francis ; Law, William ; Larue, Catherine ; Hodges, Robert S. ; Solaro, R. John. / Breakdown and release of myofilament proteins during ischemia and ischemia/reperfusion in rat hearts identification of degradation products and effects on the pCa-force relation. In: Circulation Research. 1998 ; Vol. 82, No. 2. pp. 261-271.
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