EH-myomesin splice isoform is a novel marker for dilated cardiomyopathy.
The M-band is the prominent cytoskeletal structure that cross-links the myosin and titin filaments in the middle of the sarcomere. To investigate M-band alterations in heart disease, we analyzed the expression of its main components, proteins of the myomesin family, in mouse and human cardiomyopathy. Cardiac function was assessed by echocardiography and compared to the expression pattern of myomesins evaluated with RT-PCR, Western blot, and immunofluorescent analysis. Disease progression in transgenic mouse models for dilated cardiomyopathy (DCM) was accompanied by specific M-band alterations. The dominant splice isoform in the embryonic heart, EH-myomesin, was strongly up-regulated in the failing heart and correlated with a decrease in cardiac function (R = -0.86). In addition, we have analyzed the expressions of myomesins in human myocardial biopsies (N = 40) obtained from DCM patients, DCM patients supported by a left ventricular assist device (LVAD), hypertrophic cardiomyopathy (HCM) patients and controls. Quantitative RT-PCR revealed that the EH-myomesin isoform was up-regulated 41-fold (P < 0.001) in the DCM patients compared to control patients. In DCM hearts supported by a LVAD and HCM hearts, the EH-myomesin expression was comparable to controls. Immunofluorescent analyses indicate that EH-myomesin was enhanced in a cell-specific manner, leading to a higher heterogeneity of the myocytes' cytoskeleton through the myocardial wall. We suggest that the up-regulation of EH-myomesin denotes an adaptive remodeling of the sarcomere cytoskeleton in the dilated heart and might serve as a marker for DCM in mouse and human myocardium.
Swiss Center for Regenerative Medicine, University of Zurich, Zurich, Switzerland.
Roman
R
Schoenauer
Maximilian Y
MY
Emmert
Allison
A
Felley
Elisabeth
E
Ehler
Chad
C
Brokopp
Benedikt
B
Weber
Mohamed
M
Nemir
Giuseppe G
GG
Faggian
Thierry
T
Pedrazzini
Volkmar
V
Falk
Simon P
SP
Hoerstrup
Irina
I
Agarkova
D000328:Adult; D017398:Alternative Splicing; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002311:Cardiomyopathy, Dilated / Q000000981:diagnostic imaging / Q000378:metabolism*; D064211:Connectin; D003599:Cytoskeleton / Q000378:metabolism; D018450:Disease Progression; D004452:Echocardiography; D005260:Female; D055879:Gene Knock-In Techniques; D006801:Humans; D007223:Infant; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D008875:Middle Aged; D009124:Muscle Proteins / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism*; D020033:Protein Isoforms / Q000378:metabolism; D012518:Sarcomeres / Q000378:metabolism*; D015854:Up-Regulation
D015415:Biomarkers; D064211:Connectin; D009124:Muscle Proteins; D020033:Protein Isoforms