Pharmacotherapeutic potential Cav1.4 calcium channels

We will evaluate the pharmaco-therapeutic potential of different retinal L-type calcium channels and develop a concept for viral based therapies for Cav1.4-mediated retinal diseases. Adeno-associated virus-mediated gene transfer is currently the golden standard for stable and long-term expression of transgenes in the retina. The CACNA1F sequence encoding Cav1.4 channels exceeds the genome packaging capacity of AAV vectors. To overcome this limitation, we take advantage of the split- inteins, which are small affinity tags enabling a scarless reconstitution of the split protein. This approach will further allow us to study Cav1.4 channel mutants in virally transduced retinal neurons, and consequently deepen our understanding of Cav1.4 channel dysfunction. To our current knowledge this study will be the first to probe the effectiveness of this approach for large ion channel proteins in retinal tissue and will therefore also path the way for similar investigations focusing on other voltage-gated calcium channels expressed in more than one cell types in other tissues.

This FWF project focused on evaluating the potential of gene supplementation therapies using recombinant adeno-associated virus (rAAV) vectors for treating Cav1.4 L-type calcium channel (LTCC) dysfunction in Congenital Stationary Night Blindness Type 2 (CSNB2). We successfully reconstituted Cav1.4 channels in cells and retinal photoreceptors of mice, demonstrating the effectiveness of the gene supplementation approach for large ion channel proteins in retinal tissue. Additionally, the team at the Institute of Pharmacy collaborated to develop a novel gene delivery system using phosphatase-responsive nanocarriers, showing promising results for efficient delivery of genetic materials into neuronal cell lines. Furthermore, the project investigated two disease-causing Cav1.4 variants and identified potential novel alterations in their biophysical properties, contributing to the understanding of Cav1.4 dysfunction in CSNB2. All study findings have significant implications for the development of gene therapeutic approaches and the understanding of the effects of pathogenic variants on Cav1.4 LTCC channel properties, therefore paving the way for future research in this field.