LRP5 Regulates HIF-1α Stability via Interaction with PHD2 in Ischemic Myocardium |
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Authors: | Sujin Ju Leejin Lim Kwanhwan Wi Changwon Park Young-Jae Ki Dong-Hyun Choi Heesang Song |
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Affiliation: | 1.Department of Biochemistry and Molecular Biology, Chosun University School of Medicine, Gwangju 61452, Korea; (S.J.); (K.W.);2.Cancer Mutation Research Center, Chosun University, Gwangju 61452, Korea;3.Department of Molecular & Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA 71103, USA;4.Department of Internal Medicine, Chosun University School of Medicine, Gwangju 61452, Korea; (Y.-J.K.); (D.-H.C.) |
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Abstract: | Low-density lipoprotein receptor-related protein 5 (LRP5) has been studied as a co-receptor for Wnt/β-catenin signaling. However, its role in the ischemic myocardium is largely unknown. Here, we show that LRP5 may act as a negative regulator of ischemic heart injury via its interaction with prolyl hydroxylase 2 (PHD2), resulting in hypoxia-inducible factor-1α (HIF-1α) degradation. Overexpression of LRP5 in cardiomyocytes promoted hypoxia-induced apoptotic cell death, whereas LRP5-silenced cardiomyocytes were protected from hypoxic insult. Gene expression analysis (mRNA-seq) demonstrated that overexpression of LRP5 limited the expression of HIF-1α target genes. LRP5 promoted HIF-1α degradation, as evidenced by the increased hydroxylation and shorter stability of HIF-1α under hypoxic conditions through the interaction between LRP5 and PHD2. Moreover, the specific phosphorylation of LRP5 at T1492 and S1503 is responsible for enhancing the hydroxylation activity of PHD2, resulting in HIF-1α degradation, which is independent of Wnt/β-catenin signaling. Importantly, direct myocardial delivery of adenoviral constructs, silencing LRP5 in vivo, significantly improved cardiac function in infarcted rat hearts, suggesting the potential value of LRP5 as a new target for ischemic injury treatment. |
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Keywords: | low-density lipoprotein receptor-related protein 5 myocardial infarction hypoxia-inducible factor-1α HIF-prolyl hydroxylases 2 |
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