C3 and Parkinson disease: Astrocytes have been previously reported to act as antigen-presenting cells in Parkinson’s disease post-mortem brain tissue and cultured human astrocytes, triggered by α-synuclein accumulation leading to the activation of T cells.28VCP mutant hiPSC-derived astrocytes show a cell-autonomous expression of C3 in their basal state together with an increased expression of HLA-A, which belongs to MHC class I. One of the main regulators of MHC-1 expression is transcription factor IRF-1.