Small heterodimer partner blocks cardiac hypertrophy by interfering with GATA6 signaling
Yoon Seok Nam1, Yoojung Kim1, Hosouk Joung1
1From the Department of Pharmacology and Medical Research Center for Gene Regulation (Y.S.N., Y.K., H.J., D.-H.K., N.C., H.-K.M., G.H.E., H.K.), Forensic Medicine (H.-S.K.), and Anatomy (K.-I.N.), Chonnam National University Medical School, Gwangju, Korea; Department of Pharmacology, College of Medicine, Yeungnam University, Gyeongsan, Korea (H.C.C.); Departments of Internal Medicine (I.-K.L.), Pharmacology, Brain Science and Engineering Institute (K.S.), and Ophthalmology (D.H.P.), Kyungpook National University School of Medicine, Daegu, Korea; Departments of Cardiology (Y.S.K., Y.A.) and Pediatrics (Y.K.C.), Chonnam National University Hospital, Gwangju, Korea; National Creative Research Initiatives Center for Nuclear Receptor Signals and Hormone Research Center, School of Biological Sciences and Technology, Chonnam National University, Gwangju, Korea (D.-K.K., H.-S.C.); and Korea Research Institute of Bioscience and Biotechnology, Daejeon, Korea (Y.-H.K., C.-H.L.).
Rationale:
Small heterodimer partner (SHP; NR0B2) is an atypical orphan nuclear receptor that lacks a conventional DNA-binding domain. Through interactions with other transcription factors, SHP regulates diverse biological events, including glucose metabolism in liver. However, the role of SHP in adult heart diseases has not yet been demonstrated.
Objective:
We aimed to investigate the role of SHP in adult heart in association with cardiac hypertrophy.
Methods And Results:
The roles of SHP in cardiac hypertrophy were tested in primary cultured cardiomyocytes and in animal models. SHP-null mice showed a hypertrophic phenotype. Hypertrophic stresses repressed the expression of SHP, whereas forced expression of SHP blocked the development of hypertrophy in cardiomyocytes. SHP reduced the protein amount of Gata6 and, by direct physical interaction with Gata6, interfered with the binding of Gata6 to GATA-binding elements in the promoter regions of natriuretic peptide precursor type A. Metformin, an antidiabetic agent, induced SHP and suppressed cardiac hypertrophy. The metformin-induced antihypertrophic effect was attenuated either by SHP small interfering RNA in cardiomyocytes or in SHP-null mice.
Conclusions:
These results establish SHP as a novel antihypertrophic regulator that acts by interfering with GATA6 signaling. SHP may participate in the metformin-induced antihypertrophic response.
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