Transcription Factor p73 Regulates Th1 Differentiation

Inter-individual differences in T helper (Th) cell responses affect susceptibility to infectious, allergic, and autoimmune diseases. To identify factors contributing to these response differences, we analyzed the phenotypic profiles of in vitro-differentiated Th1 cells from 16 inbred mouse strains. Haplotype-based computational genetic analysis indicated that the p53 family protein, p73, affected Th1 differentiation. In cells differentiated under Th1 conditions in vitro, we demonstrated that p73 was a negative regulator of IFN? production, and this effect required the DNA-binding activity of p73. p73 bound within the gene body or upstream of many genes that affect Th1 differentiation and regulated their expression (e.g., Ifng and Il12rb2). Furthermore, in experimental autoimmune encephalitis, which is a mouse disease model of multiple sclerosis, p73-deficient mice had increased IFNg production and decreased disease severity, whereas in the adoptive transfer model of inflammatory bowel disease, transfer of p73- deficient nai¨ve CD4+ T cells into WT Rag2-/- hosts resulted in increased Th1 responses and enhanced disease severity compared to transfer of WT cells. These studies identify p73 as a regulator of immune responses and indicate that its dysregulation may play a role in susceptibility to autoimmune disease. Overall design: ChIP-Seq and RNA-Seq using naïve CD4+ T cells that were polarized in Th1 conditions for 3 days