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MEK1‐induced physiological hypertrophy inhibits chronic post‐myocardial infarction remodeling in mice
Author(s) -
Yeh CheChung,
Malhotra Deepak,
Yang YiLin,
Xu Yanchun,
Fan Yanying,
Li Hongzhe,
Mann Michael J.
Publication year - 2013
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.24299
Subject(s) - medicine , phosphorylation , myocardial infarction , ventricular remodeling , endocrinology , apoptosis , preload , cardiology , fibrosis , mapk/erk pathway , stat3 , downregulation and upregulation , signal transduction , muscle hypertrophy , genetically modified mouse , transgene , chemistry , biology , microbiology and biotechnology , hemodynamics , biochemistry , gene
Although activation of MEK‐ERK signaling is known to be cardioprotective during acute reperfusion injury, the effect of MEK activation on chronic changes in ventricular structure and function during the more complex process of remodeling after myocardial infarction (MI) with or without reperfusion remains uncertain. Four weeks after permanent coronary ligation, LV fractional shorting, preload recruitable stroke work, and end‐systolic elastance were all preserved in transgenic mice with CM‐specific upregulation of the MEK1‐ERK1/2 signaling pathway (MEK1 Tg) compared to wildtype (WT) controls (5.8% decline vs. 17.3%, P < 0.01; 603 ± 98 mmHg vs. 335 ± 98, P < 0.05; 6.14 ± 0.57 mmHg/µl vs. 3.92 ± 0.60, P < 0.05, respectively). Despite similar initial infarct sizes, post‐MI remodeling was significantly reduced in MEK1 Tg, demonstrated by reductions in chronic infarct size (28.5 ± 3.1% vs. 47.8 ± 3.2%), myocardial fibrosis (3.98 ± 0.74% vs. 9.27 ± 1.97%) and apoptosis (0.66 ± 0.11% vs. 1.60 ± 0.34%). Higher phosphorylation (i.e., activation) of pro‐survival transcription factor STAT3, higher expression of anti‐apoptotic protein Bcl2, and higher phosphorylation (i.e., inactivation) of pro‐apoptotic BAD were observed in the post‐MI remote myocardium of MEK1 Tg. MMP2 activity was higher in MEK1 Tg, while expression of TIMP3 and MMP9 activity were lower in transgenic mice. Beyond any immediate cardioprotective effect, therapeutic activation of MEK1‐ERK1/2 signaling during the chronic post‐MI period may preserve LV function by increasing the expression of pro‐survival factors and by suppressing factors, such as the balance between matrix modulating proteins, that promote pathological remodeling in the remote myocardium. J. Cell. Biochem. 114: 47–55, 2012. © 2012 Wiley Periodicals, Inc.