#6839 MULTIDISCIPLINARY APPROACH TO STUDY THE BIOLOGICAL FUNCTION OF BBS10 IN THE PATHOGENESIS OF BARDET-BIEDL SYNDROME (BBS)

Bardet-Biedl Syndrome (BBS) is a rare inherited ciliopathy resulting in multiple organ dysfunctions, including chronic kidney disease (CKD). Although BBS is highly heterogenous at genetic level, BBS10 is one of the significant causative genes, accounting for almost 30% of cases of BBS cases in western countries. Despite the recent progress in the ciliopathy field, there is still little information on the mechanisms underlying renal disease. To elucidate the pathomechanisms, we have broadened the study's criteria into a combination of the in silico-in vitro approach.

This study integrates the molecular dynamics (MD) simulations with the results of nine distinct (SIFT, SNAP2, PROVEAN, Align-GVGD, ConSurf, I Mutant, MuPro, PremPS, and Dynamut) in silico pathogenicity prediction tools. For in vitro studies we have used the inner medulla renal epithelial cells lacking Bbs10 (IMCD3-Bbs10-/-cells). MTT assay, Colony formation assay, Real time PCR, Western Blot and other experiments were performed using the cultured wild-type and IMCD3-Bbs-/-cells. BBS10 interactors have been studied using Mass Spec, after pulling down BBS10-FLAG in renal epithelial cells expressing the protein, after transfection.

Our in-silico results showed that six BBS10 missense variants (Ser191Leu, Cys19Gly, Ile342Thr, Cys371Ser, Ala417Glu, and Tyr613Cys) could be potentially deleterious. IMCD3-BBS10-/-cells showed hyperproliferation, increased aerobic glycolysis and sings of mitochondrial dysfunction. Additionally, among BBS10 interactors in vitro, we found several proteins involved in cellular metabolism and mitochondrial-related function. Interestingly, Bbs10 depletion affected PINK1/PARKIN signalling, leading to the disruption of mitochondria quality control.

This multi-disciplinary approach could open new avenues to study the extra-ciliary biological function of BBS10 in renal epithelial cells and providing novel clues into our understanding of disease pathomechanisms.