Pre-Clinical In-Vitro Assays for High Throughput Screening of Drug Candidates for Protection and Restoration of Immune Privilege in Alopecia Areata

The study aimed to develop in vitro models for high-throughput screening of drugs that can protect and restore immune privilege (IP) in alopecia areata (AA), a condition characterized by inflammatory hair loss. The researchers used Interferon-γ (IFNγ) to simulate IP collapse-like responses in human outer root sheath (ORSK) keratinocytes and epidermal keratinocytes (NHEK). They validated the model using α-melanocyte stimulating hormone (αMSH), Tacrolimus, and Tofacitinib, drugs known to protect and restore HF IP. IFNγ significantly increased mRNA and protein expression of MHC class Ia and II (MHCI/II), and increased CXCL10 release into the medium in both NHEK and ORSK. Tofacitinib significantly prevented the up-regulation of IP-collapse markers and CXCL10 secretion in both cell types, while Tacrolimus and αMSH successfully prevented MHCI/II increase exclusively in ORSK. The data suggest that both NHEK and ORSK can be used to screen drugs interfering with IFNg signaling, but only ORSK are suitable for testing IP protective/restorative candidate drugs targeting other pathways.