Novel Kinase Inhibitors Reduce Hypoxia‐Induced Apoptosis in Cardiomyocytes

Abstract

Our previous data suggest that bone morphogenic protein 2‐inducible kinase (BMP2K) plays a significant role in the pathophysiology of hypoxia/reoxygenation injury in cardiomyocytes, and that a reduction in BMP2K expression reduces apoptosis in cardiomyocytes. BMP2K and adaptor‐associated kinase 1 (AAK1) are human homologs of the drosophila Numb‐associated protein kinase (NAK). The function of BMP2K is unknown, and there are no identified physiological substrates. BMP2K shares a 74% sequence homology with the kinase domain of AAK1. Novel dual inhibitors of AAK1 and BMP2K, SGC‐AAK1‐1 and LP935509, have recently been developed. Because knockdown of BMP2K in cardiomyocytes protects against hypoxia‐induced cell death, we hypothesized that SGC‐AAK1‐1 and LP935509 would produce the same effect. To test our hypothesis, we pretreated H9c2 cardiomyocyte cells with SGC‐AAK1‐1, LP935509, or an inactive control compound SGC‐AAK1‐1N before subjecting the cells to hypoxic conditions. By analyzing cleaved caspase‐3 and cleaved PARP levels via immunoblotting, we determined that 3 μM of SGC‐AAK1‐1 or LP935509 reduced apoptosis. Since these compounds inhibit both AAK1 and BMP2K with similar potencies, we wanted to determine which kinase was responsible for reduced apoptosis. We observed that transfection of H9c2 cells with BMP2K siRNA, but not AAK1 siRNA, reduced hypoxia‐induced apoptosis. In addition, BMP2K siRNA increased overall cell viability. Phosphoantibody arrays are currently being done to assess the effect of SCG‐AAK1‐1 on cellular kinase signaling. Ongoing experimental objectives are to identify the mechanism by which these kinase inhibitors protect cardiomyocytes in hypoxic conditions, and characterize the substrates of BMP2K.Support or Funding InformationAmerican Heart Association (15SDG25090279) and Iowa Osteopathic Education and Research Funds (E.M.W.)This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.