In:
Circulation Research, Ovid Technologies (Wolters Kluwer Health), Vol. 119, No. suppl_1 ( 2016-07-22)
Abstract:
Cardiac remodeling is a typical change in function and morphology of the heart in response to pathological biomechanical stress. Despite substantial research in this area several underlying mechanisms remain unclear. We thus devised a screening experiment of dynamic stretch of neonatal cardiomyocytes (NRVCM) which revealed several genes which have not yet been implicated in cardiac remodeling before. In further analyses we focused on Mlf1 and Rnd1 , both showing significant expression in heart as well as in skeletal and liver. Conformational qRT-PCR revealed upregulation of Rnd1 mRNA (5.94x) after 24 h of stretch. Mlf1 mRNA was significantly downregulated (qRT-PCR 0.34x). Stimulation with phenylephrine (PE) induced Rnd1 mRNA (3.98x), while Mlf1 mRNA levels remained unchanged. Furthermore, in line with the in vitro results we found upregulation of Rnd1 (2.1x, p 〈 0.001) and downregulation of the cardiac Mlf1 expression (var. 1 0.45x, var. 2 0.36x, both p 〈 0.001) in mice after transverse aortic constriction. Adenoviral overexpression of Mlf1 in NRVCM induced the fetal gene program (e.g., nppa , nppb ). However, a significant decrease in cell size was found. We noticed the consistent findings after stretch or PE-stimulation. Rnd1 overexpression also led to induction of nppa , nppb and Rcan1.4, but caused an increase in cell size. To analyze whether Mlf1 and Rnd1 also influenced cell proliferation, we analyzed Mlf1/Rnd1-infected cells for the expression of proliferation markers Ki67 and phosphohistone H3 (PHH3). Mlf1 overexpression led to an increase in Ki67+ cells of about 5.92 fold, and in PHH3+ cells of 2.48 fold (p 〈 0.001), Rnd1 overexpression showed an increase in Ki67+ cells of about 6.9 fold and in PHH3+ cells of 5,25 fold (p 〈 0.001). Taken together, we could identify two stretch-sensitive genes which influence the process of cardiac hypertrophy and cell proliferation. Current work focuses on a knockdown of both genes in vivo and on the identification of potential protein-protein interactions to complete the characterization of Mlf1 and Rnd1.
Type of Medium:
Online Resource
ISSN:
0009-7330
,
1524-4571
DOI:
10.1161/res.119.suppl_1.93
Language:
English
Publisher:
Ovid Technologies (Wolters Kluwer Health)
Publication Date:
2016
detail.hit.zdb_id:
1467838-X
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