Progressive liver, kidney, and heart degeneration in children and adults affected by TULP3 mutations

Organ fibrosis is a shared endpoint of many diseases, yet underlying mechanisms are not well understood. Several pathways governed by the primary cilium, a sensory antenna present on most vertebrate cells, have been linked with fibrosis. Ciliopathies usually start early in life and represent a considerable disease burden. We performed massively parallel sequencing by using cohorts of genetically unsolved individuals with unexplained liver and kidney failure and correlated this with clinical, imaging, and histopathological analyses. Mechanistic studies were conducted with a vertebrate model and primary cells. We detected bi-allelic deleterious variants in TULP3, encoding a critical adaptor protein for ciliary trafficking, in a total of 15 mostly adult individuals, originating from eight unrelated families, with progressive degenerative liver fibrosis, fibrocystic kidney disease, and hypertrophic cardiomyopathy with atypical fibrotic patterns on histopathology. We recapitulated the human phenotype in adult zebrafish and confirmed disruption of critical ciliary cargo composition in several primary cell lines derived from affected individuals. Further, we show interaction between TULP3 and the nuclear deacetylase SIRT1, with roles in DNA damage repair and fibrosis, and report increased DNA damage ex vivo. Transcriptomic studies demonstrated upregulation of profibrotic pathways with gene clusters for hypertrophic cardiomyopathy and WNT and TGF-β signaling. These findings identify variants in TULP3 as a monogenic cause for progressive degenerative disease of major organs in which affected individuals benefit from early detection and improved clinical management. Elucidation of mechanisms crucial for DNA damage repair and tissue maintenance will guide novel therapeutic avenues for this and similar genetic and non-genomic diseases.

Comprehensive Profiling of Tubby-Like Protein Expression Uncovers Ripening-Related TLP Genes in Tomato (Solanum lycopersicum)

Tubby-like proteins (TLPs), which were firstly identified in obese mice, play important roles in male gametophyte development, biotic stress response, and abiotic stress responses in plants. To date, the role of TLP genes in fruit ripening is largely unknown. Here, through a bioinformatics analysis, we identified 11 TLPs which can be divided into three subgroups in tomato (Solanum lycopersicum), a model plant for studying fruit development and ripening. It was shown that all SlTLPs except SlTLP11 contain both the Tub domain and F-box domain. An expression profiling analysis in different tomato tissues and developmental stages showed that 7 TLP genes are mainly expressed in vegetative tissues, flower, and early fruit developmental stages. Interestingly, other 4 TLP members (SlTLP1, SlTLP2, SlTLP4, and SlTLP5) were found to be highly expressed after breaker stage, suggesting a potential role of these genes in fruit ripening. Moreover, the induced expression of SlTLP1 and SlTLP2 by exogenous ethylene treatment and the down expression of the two genes in ripening mutants, further support their putative role in the ripening process. Overall, our study provides a basis for further investigation of the function of TLPs in plant development and fruit ripening.