Enhanced thrombospondin-1 causes dysfunction of vascular endothelial cells derived from Fabry disease-induced pluripotent stem cells.

Background: Fabry disease (FD) is a recessive X-linked lysosomal storage disorder caused by α-galactosidase A (GLA) deficiency. Although the mechanism is unclear, GLA deficiency causes an accumulation of globotriaosylceramide (Gb3), leading to vasculopathy.
Methods: To explore the relationship between the accumulation of Gb3 and vasculopathy, induced pluripotent stem cells generated from four Fabry patients (FD-iPSCs) were differentiated into vascular endothelial cells (VECs). Genome editing using CRISPR-Cas9 system was carried out to correct the GLA mutation or to delete Thrombospondin-1 (TSP-1). Global transcriptomes were compared between wild-type (WT)- and FD-VECs by RNA-sequencing analysis.
Findings: Here, we report that overexpression of TSP-1 contributes to the dysfunction of VECs in FD. VECs originating from FD-iPSCs (FD-VECs) showed aberrant angiogenic functionality even upon treatment with recombinant α-galactosidase. Intriguingly, FD-VECs produced more p-SMAD2 and TSP-1 than WT-VECs. We also found elevated TSP-1 in the peritubular capillaries of renal tissues biopsied from FD patients. Inhibition of SMAD2 signaling or knock out of TSP-1 (TSP-1 ^-/- ) rescues normal vascular functionality in FD-VECs, like in gene-corrected FD-VECs. In addition, the enhanced oxygen consumption rate is reduced in TSP-1 ^-/- FD-VECs.
Interpretation: The overexpression of TSP-1 secondary to Gb3 accumulation is primarily responsible for the observed FD-VEC dysfunction. Our findings implicate dysfunctional VEC angiogenesis in the peritubular capillaries in some of the complications of Fabry disease.
Funding: This study was supported by grant 2018M3A9H1078330 from the National Research Foundation of the Republic of Korea.
(Copyright © 2020 The Author(s). Published by Elsevier B.V. All rights reserved.)