Transgenic modeling of a cardiac troponin I mutation linked to familial hypertrophic cardiomyopathy. Circ Res 2000 Oct 27;87(9):805-11
Date
10/31/2000Pubmed ID
11055985DOI
10.1161/01.res.87.9.805Scopus ID
2-s2.0-0034721807 (requires institutional sign-in at Scopus site) 121 CitationsAbstract
Multiple mutations in cardiac troponin I (cTnI) have been associated with familial hypertrophic cardiomyopathy. Two mutations are located in the cTnI inhibitory domain, a highly negatively charged region that alternately binds to either actin or troponin C, depending on the intracellular concentration of calcium. This region is critical to the inhibition of actin-myosin crossbridge formation when intracellular calcium is low. We modeled one of the inhibitory domain mutations, arginine145-->glycine (TnI(146Gly) in the mouse sequence), by cardiac-specific expression of the mutated protein in transgenic mice. Multiple lines were generated with varying degrees of expression to establish a dose relationship; the severity of phenotype could be correlated directly with transgene expression levels. Transgenic mice overexpressing wild-type cTnI were generated as controls and analyzed in parallel with the TnI(146Gly) animals. The control mice showed no abnormalities, indicating that the phenotype of TnI(146Gly) was not simply an artifact of transgenesis. In contrast, TnI(146Gly) mice showed cardiomyocyte disarray and interstitial fibrosis and suffered premature death. The functional alterations that seem to be responsible for the development of cardiac disease include increased skinned fiber sensitivity to calcium and, at the whole organ level, hypercontractility with diastolic dysfunction. Severely affected lines develop a pathology similar to human familial hypertrophic cardiomyopathy but within a dramatically shortened time frame. These data establish the causality of this mutation for cardiac disease, provide an animal model for understanding the resultant pathogenic structure-function relationships, and highlight the differences in phenotype severity of the troponin mutations between human and mouse hearts.
Author List
James J, Zhang Y, Osinska H, Sanbe A, Klevitsky R, Hewett TE, Robbins JMESH terms used to index this publication - Major topics in bold
ActinsAge Factors
Amino Acid Substitution
Animals
Calcium
Cardiomyopathy, Hypertrophic
Female
Male
Mice
Mice, Transgenic
Models, Animal
Mutation
Myocardium
Myosins
Phenotype
Protein Isoforms
RNA
Structure-Activity Relationship
Survival Analysis
Troponin I