Abstract 14173: Generation and Characterization of Clinically Relevant Disease Models for Port Wine Birthmark Using Induced Pluripotent Stem Cells

Abstract

Introduction: Port Wine Birthmark (PWB) is a congenital vascular malformation with a progressive development. The current treatments for PWB are Pulse Dye Laser and Photodynamic Laser Treatment. However, the efficacy of blanching the birthmark is inadequate, and the reoccurrence after treatment is a major clinical barrier. Developing clinically relevant disease models that can be used for mechanistic and therapeutic development studies is the critical unmet need. Induced pluripotent stem cell (iPSC) is a powerful tool in different disease models and drug discovery. Besides, iPSC-derived cells can retain and exhibit the disease phenotypes from donors. Therefore, iPSCs and their-derived vascular cells could be potential models for PWB study. Hypothesis: It was hypothesized that PWB iPSC-derived endothelial cell (EC) could retain the disease phenotypes, thus serving as clinically relevant disease models. Methods: PWB lesions and normal skin biopsies were cultured for outgrowths of fibroblasts, followed by reprogramming using CytoTune-iPS Kit. The induction of PWB and normal iPSC into EC was performed using reported protocols with tailored modifications. Bulk RNA and ATAC-seq were performed on both iPSC and iPSC-derived EC. The functional phenotypes of iPSC-derived ECs were characterized using in vitro capillary formation and in vivo Matrigel plug-in assays. Results: PWB EC showed impaired tube formation in vitro with larger perimeters (p=6.22x10 -24 ) and thicker branches (p=1.07x10 -77 ) comparing with normal EC. In plug-in assay, the perfused human vasculatures were characterized by using UEA1 and anti-human CD31 antibodies. Perfused vasculature formed by PWB EC showed larger perimeters (p=8.45x10 -6 ) and greater densities (p=7.34x10 -8 ) than those formed by normal EC. Additionally, 16.6% of perfused vessels formed by PWB EC showed perimeters over 300 μm. KEGG analysis of RNA-seq DEGs showed significantly dysregulated pathways related to cell differentiation, organ development, and lipid metabolism in PWB iPSCs and ECs as compared with normal ones. Conclusions: PWB-derived EC retained critical disease related phenotypes including forming enlarged vessels and thick branches in vitro and in vivo, which can be utilized as valuable PWB models.