Cellular modelling of Alstr?m syndrome in human primary dermal fibroblasts and derived cells

摘要

Alstr?m syndrome (AS) is a complex disorder whose manifestationsinclude retinal degeneration, sensorineural hearingloss, cardiomyopathy, liver fibrosis, and severe insulinresistance. It is caused by biallelic loss-of-function mutationsin the ALMS1 gene, encoding a large centrosomalprotein of poorly understood function. Although the syndromeencompasses several cardinal features of ciliopathies,primary cilia have been reported to be morphologicallynormal in primary cells from patients with AS. In orderto dissect out the cellular pathology of AS in humans wehave now, in a project led by Alstr?m UK, assembled abank of dermal fibroblasts from patients with AS. All 11cell lines studied to date show normal primary cilia onserum starvation. 3/11 lines express near normal levels ofALMS1 protein at the centrosome despite biallelic ALMS1mutations, which will permit refinement of existing genotype-phenotype correlations in AS.We have also generatedinduced pluripotent stem cells that will be differentiatedinto cell types relevant to the organ-specific pathologies ofAS including cardiomyocytes, hepatocytes and adipocytes.Finally we have used lentivirally-mediated expression of theadipose differentiation regulator PPARgamma2 to reprogrammehuman dermal fibroblasts to adipocytes. We havedeveloped a highly efficient protocol to produce cells thataccumulate triglyceride, show a pattern of gene expressionconsistent with adipocytes, secrete adiponectin and leptin,and respond physiologically to insulin. Collectively thesedevelopments constitute a valuable cellular resource forstudying the cellular pathology of AS, and may form thebasis of preclinical treatment screens in future.