Differential interactions of thin filament proteins in two cardiac troponin T mouse models of hypertrophic and dilated cardiomyopathies

AIM: Mutations in a sarcomeric protein can cause hypertrophic cardiomyopathy (HCM) or dilated cardiomyopathy (DCM), the opposite ends of a spectrum of phenotypic responses of the heart to mutations. We posit the contracting phenotypes could result from differential effects of the mutant proteins on interactions among the sarcomeric proteins. To test the hypothesis, we generated transgenic mice expressing either cardiac troponin T (cTnT)-Q92 or cTnT-W141, known to cause HCM and DCM, respectively, in the heart.

METHODS AND RESULTS: We phenotyped the mice by echocardiography, histology and immunoblotting, and real-time polymerase chain reaction. We detected interactions between the sarcomeric proteins by co-immunoprecipitation and determined Ca2+ sensitivity of myofibrillar protein ATPase activity by Carter assay. The cTnT-W141 mice exhibited dilated hearts and decreased systolic function. In contrast, the cTnT-Q92 mice showed smaller ventricles and enhanced systolic function. Levels of cardiac troponin I, cardiac alpha-actin, alpha-tropomyosin, and cardiac troponin C co-immunoprecipitated with anti-cTnT antibodies were higher in the cTnT-W141 than in the cTnT-Q92 mice, as were levels of alpha-tropomyosin co-immunoprecipitated with an anti-cardiac alpha-actin antibody. In contrast, levels of cardiac troponin I co-immunoprecipitated with an anti-cardiac alpha-actin antibody were higher in the cTnT-Q92 mice. Ca2+ sensitivity of myofibrillar ATPase activity was increased in HCM but decreased in DCM mice compared with non-transgenic mice.

CONCLUSION: Differential interactions among the sarcomeric proteins containing cTnT-Q92 or cTnT-W141 are responsible for the contrasting phenotypes of HCM or DCM, respectively.

Medienart:

E-Artikel

Erscheinungsjahr:

2008

Erschienen:

2008

Enthalten in:

Zur Gesamtaufnahme - volume:79

Enthalten in:

Cardiovascular research - 79(2008), 1 vom: 01. Juli, Seite 109-17

Sprache:

Englisch

Beteiligte Personen:

Lombardi, Raffaella [VerfasserIn]
Bell, Achim [VerfasserIn]
Senthil, Vinitha [VerfasserIn]
Sidhu, Jasvinder [VerfasserIn]
Noseda, Michela [VerfasserIn]
Roberts, Robert [VerfasserIn]
Marian, Ali J [VerfasserIn]

Links:

Volltext

Themen:

127869-51-6
85637-73-6
Adenosine Triphosphatases
Atrial Natriuretic Factor
Calcium
EC 3.6.1.-
Journal Article
Natriuretic Peptide, C-Type
Nppa protein, mouse
Protein Precursors
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
SY7Q814VUP
Troponin T

Anmerkungen:

Date Completed 14.10.2008

Date Revised 20.10.2021

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1093/cvr/cvn078

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM178325694