Inhibition of transforming growth factor-beta signaling induces left ventricular dilation and dysfunction in the pressure-overloaded heart.
This study utilized a transgenic mouse model that expresses an inducible dominant-negative mutation of the transforming growth factor (TGF)-beta type II receptor (DnTGFbetaRII) to define the structural and functional responses of the left ventricle (LV) to pressure-overload stress in the absence of an intact TGF-beta signaling cascade. DnTGFbetaRII and nontransgenic (NTG) control mice (male, 8-10 wk) were randomized to receive Zn(2+) (25 mM ZnSO(4) in drinking H(2)O to induce DnTGFbetaRII gene expression) or control tap H(2)O and then further randomized to undergo transverse aortic constriction (TAC) or sham surgery. At 7 days post-TAC, interstitial nonmyocyte proliferation (Ki67 staining) was greatly reduced in LV of DnTGFbetaRII+Zn(2+) mice compared with the other TAC groups. At 28 and 120 days post-TAC, collagen deposition (picrosirius-red staining) in LV was attenuated in DnTGFbetaRII+Zn(2+) mice compared with the other TAC groups. LV end systolic diameter and end systolic and end diastolic volumes were markedly increased, while ejection fraction and fractional shortening were significantly decreased in TAC-DnTGFbetaRII+Zn(2+) mice compared with the other groups at 120 days post-TAC. These data indicate that interruption of TGF-beta signaling attenuates pressure-overload-induced interstitial nonmyocyte proliferation and collagen deposition and promotes LV dilation and dysfunction in the pressure-overloaded heart, thus creating a novel model of dilated cardiomyopathy.
Lucas
Jason A
JA
Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA.
Zhang
Yun
Y
Li
Peng
P
Gong
Kaizheng
K
Miller
Andrew P
AP
Hassan
Erum
E
Hage
Fadi
F
Xing
Dongqi
D
Wells
Bryan
B
Oparil
Suzanne
S
Chen
Yiu-Fai
YF
D000818:Animals; D002311:Cardiomyopathy, Dilated / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D049109:Cell Proliferation; D003094:Collagen / Q000378:metabolism; D004195:Disease Models, Animal; D005347:Fibroblasts / Q000473:pathology; D006321:Heart / Q000187:drug effects / Q000503:physiopathology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D000077294:Receptor, Transforming Growth Factor-beta Type II; D018125:Receptors, Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D051785:Smad Proteins / Q000378:metabolism; D013997:Time Factors; D016212:Transforming Growth Factor beta / Q000037:antagonists & inhibitors* / Q000378:metabolism; D014664:Vasodilation / Q000502:physiology*; D018487:Ventricular Dysfunction, Left / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D019287:Zinc Sulfate / Q000494:pharmacology
D018125:Receptors, Transforming Growth Factor beta; D051785:Smad Proteins; D016212:Transforming Growth Factor beta; D019287:Zinc Sulfate; D003094:Collagen; D017346:Protein Serine-Threonine Kinases; D000077294:Receptor, Transforming Growth Factor-beta Type II