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Ge Y.,Translational Medicine Program | Ge Y.,Jiangxi Cardiovascular Research Institute | Ge Y.,Nanjing Medical University | Pan S.,Translational Medicine Program | And 14 more authors.
Biochimica et Biophysica Acta - Molecular Basis of Disease | Year: 2013

Recent studies have identified important roles for microRNAs (miRNAs) in many cardiac pathophysiological processes, including the regulation of cardiomyocyte hypertrophy. However, the role of miR-350 in the cardiac setting is still unclear. The objective of this study is to determine whether miR-350 alone can induce pathological cardiac hypertrophy by repressing the SAPK pathway in cardiomyocytes. Here we report that miR-350 plays a key role in determining pathological cardiomyocyte hypertrophy and apoptosis. Comprehensive microarray profiling of miRs and qPCR showed that this unique miRNA was significantly up-regulated in rat hearts in response to late-stage transverse aortic constriction. Western blotting and luciferase assays confirmed that the target mRNAs of miR-350 are mitogen activated protein kinase (MAPK) 11/14 and MAPK8/9 gene transcripts. Gain-of-unction and loss-of-function approaches were used to investigate the functional roles of miR-350. The forced over-expression of miR-350 was sufficient to induce hypertrophy of cardiomyocytes through the posttranslational suppression of p38 and JNK protein synthesis. Moreover, miR-350 led to an increase in unphosphorylated NFATc3 and its nuclear translocation, resulting in the over-expression of pathological hypertrophy markers. As predicted, these effects could effectively be imitated by siR-JNK/p38 through the degeneration of p38 and JNK mRNAs. Conversely, antagomir-350 could lower the levels of miR-350, reverse the expression of target proteins and reduce cell size and apoptosis relative to the administration of mutant antagomir-350. Our data provide the first evidence that miR-350 is a critical regulator of pathological cardiac hypertrophy and apoptosis in rats. © 2012 Elsevier B.V.

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