Autoimmune polyglandular syndrome type 1 (APS1) is a severe and incurable autoimmune disease caused by mutations in the AIRE gene. Without functional AIRE immune tolerance is impaired as self-reactive T cells escape from negative selection and a variety of autoantibodies develop. Recently AIRE has also been found to have novel functions in stem cells and to actively participate in pluripotency. We have pioneered a pilot study to assess the potential of patient-derived, gene-corrected induced pluripotent stem cells (iPSCs) for use as cell therapy in APS1. We generated iPSCs from multiple APS1 patients and used immunohistochemistry (IHC) and realtime PCR (qPCR) to assess expression of the classical stem cell factors Oct4, Sox2, Nanog, and Lin28. We also generated embryoid body (EB) organoids to assess possible differences in differentiation potential, morphology, proliferation (Ki67) and apoptosis (TUNEL). Our data show that APS1-derived iPSCs and EBs express all stemness markers similarly to healthy controls and had a comparable decrease of 50% or more upon EB maturation (30 days, as measured by qPCR and IHC). Also, their overall morphology, proliferation and apoptosis do not differ from healthy controls with Ki67 positivity increasing during maturation by two-fold to all EB being approx. 50% Ki67+ on day 30. These data suggest that patient iPSCs are amenable to gene correction using our lentiviral vector containing functional AIRE and these experiments are underway. Since AIRE is expressed in peripheral tissues such as the skin and lymph nodes and as we show, with distinct expression in keratinocytes, we will differentiate gene-corrected iPSCs into keratinocytes and assess their potential for therapeutic re-introduction using a rat model of APECED which faithfully recapitulates the human disease. To our knowledge, this is the first study characterizing APS1-patient derived iPSCs. We propose that gene-correction and differentiation of iPSCs could offer a cell therapy for APS1.

ESDR181 - Characterization of APS1 patient-derived induced pluripotent stem cells for potential therapeutic gene correction

50th Annual Meeting of the European Society for Dermatological Research. VIRTUAL MEETING