ROR2 Drives Right Ventricular Heart Failure Through Disruption of Proteostasis

BACKGROUND: No therapies exist to reverse right ventricular failure (RVF), and the molecular mechanisms that drive RVF remain understudied. We recently reported that the developmentally restricted noncanonical WNT receptor ROR2 (receptor tyrosine kinase-like orphan receptor 2) is upregulated in human RVF in proportion to severity of disease. Here we test the mechanistic role of ROR2 in RVF pathogenesis. METHODS: ROR2 was overexpressed or knocked down in neonatal rat ventricular myocytes and then characterized using confocal microscopy, RNA sequencing, proteomics, proteostatic functional assays, and pacing to assess contractile properties. The impact of cardiac ROR2 expression was evaluated in mice by AAV9-mediated overexpression and by AAV9-mediated delivery of short hairpin RNA to knockdown ROR2 in a pulmonary artery banded pressure overload model of RVF. ROR2 -modified mice were evaluated by echocardiography, histology, and right ventricle protein synthesis and proteasome capacity. RESULTS: In neonatal rat ventricular myocytes, we find that ROR2 profoundly dysregulates the coordination between protein translation and folding. This imbalance leads to excess protein clearance by the ubiquitin proteasome system with dramatic impacts on sarcomere and cytoskeletal structure and function. Inhibiting the ubiquitin proteasome system or restoring chaperone expression is sufficient to partially rescue ROR2-induced structural and contractile deficits in cardiomyocytes. In mice, forced cardiac ROR2 expression is sufficient to disrupt proteostasis and drive RVF, whereas conversely Ror2 knockdown partially rescues proteostasis and right ventricle structure and function in a pressure overload model of RVF. CONCLUSIONS: In sum, ROR2 is a key driver of RVF pathogenesis through proteostatic disruption and thus provides a promising target to treat RVF.