Loss of Bbs8 leads to cystic kidney disease in mice and affects tubulin acetylation through HDAC2

Abstract

Bardet-Biedl Syndrome (BBS) is a genetic disorder marked by considerable genetic and phenotypic diversity. BBS often presents as a combination of retinitis pigmentosa, obesity, polydactyly, and cystic kidney disease and is considered a model ciliopathy. The syndrome is caused by pathogenic variants in BBS genes, some of which encode components of a ciliary multi-protein complex, known as the BBSome, as well as a chaperonin-like complex, which is required for BBSome assembly. In this study, we describe the occurrence of kidney cysts in a BBS mouse model. Specifically, loss of BBS8 led to the development of cystic kidney disease by the end of the first year of life. In addition to transcriptional changes of key genes involved in regulated cell death and inflammation, proteomic approaches revealed increased expression and altered phosphorylation of histone deacetylase HDAC2 in knockout kidneys. Consistently, loss of Bbs8 resulted in a reduction of acetylated alpha-tubulin in primary cilia. This leads to diminished stability and altered dynamics of primary cilia, potentially contributing to the formation of cystic kidneys and other BBS manifestations previously described in Bbs8 deficient mice.