Unraveling the molecular pathomechanisms in PRKG1 variant-associated aortopathies

• Applicants: Professorin Dr. Friederike Cuello; Dr. Till Joscha Demal; Professor Dr. Friedrich-Wilhelm Herberg
• Subject Area: Pharmacology
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 543016709

Inherited thoracic aortic diseases can lead to life-threatening complications like aortic dissections at young age, which are associated with a high mortality. The aortic diameter is a measurable risk predictor that is not always adequate as a large proportion of events occurs below the threshold of 5.5 cm. To improve risk prediction in affected patients, genetic testing of known disease genes is performed. However, most causal genes and genetic variants remain unknown to date and function-al readouts to prove causality hardly exist. In the present proposal, we aim to establish the gene encoding for cGMP-dependent protein kinase I - PRKG1 - as a bona fide risk gene causally leading to aortopathies, if mutated. We teamed up as a complementary workgroup comprising expertise from the human genetics/clinical, biochemical and pharmacological/stem cell biology field to work together and bridge the gap from basic science to clinical translation. We provide pilot data on the functional characterization of a human mutation V219I in PRKG1 from a patient with Marfan-like symptoms including borderline aortic dilation and demonstrate significantly enhanced cGMP-affinity of V219I PRKG1 leading to higher kinase activity at lower cellular cGMP levels. Human induced pluripotent stem cell-derived vascular smooth muscle cells expressing V219I PRKG1 by CRISPR Cas9-mediated genome editing displayed significantly increased cell area and enhanced cellular deformability than the isogenic control cells, Proteomic analysis unveiled alterations in extracellular matrix composition and mechanotransduction as the most differentially regulated biological pathways between genotypes. In the present project, we aim to 1) identify novel PRKG1 variants; 2) to perform a thorough characterization of their impact on kinase function in vitro and 3) on the underlying molecular pathomechanisms by disease modeling in a relevant human induced pluripotent stem cell-derived vascular smooth muscle cell model. We envisage that our proposal will deepen our understanding on the pathogenesis of PRKG1 variant-associated aortopathies and improve risk predictions and stratifications in patients carrying PRKG1 mutations.

• DFG Programme: Research Grants