Neddylation regulates T cell responses. (TRAN3P.914)

Abstract

Abstract Post-translational modifications (PTM) of proteins regulate cellular processes by proteasomal degradation. PTM of Cullin-RING ligase (CRL) protein via neddylation and the presence of its critical adapter element, sensitive to apoptosis gene (SAG) protein, modulate the process of neddylation-dependent ubiquitination. The role of neddylated proteins in regulating T cells is not known. We explored the role of neddylation in T cells by utilizing two different, but complementary approaches. We generated a T-cell specific knockout (SLCK-KO) of SAG (critical for the neddylation process) and utilized a small molecule inhibitor specific for neddylation (MLN4924). Phenotypic analysis of thymic and splenic T cells from SLCK-KO showed no differences when compared to WT. In vitro analysis of SLCK-KO T cells, with either allo-splenocytes or non-specific CD3/CD28 antibodies demonstrated reduced activation (CD69, CD44), proliferation, and secretion of T helper signature cytokines (IFNγ, IL-4, IL-17) (P<0.003). In vivo studies utilizing multiple MHC disparate models of BMT (B6→BALB/c, B6→B6D2F1), demonstrated that SLCK-KO T cells in the recipient animals caused reduced severity of GVHD and increased survival (P<0.01). Similar results were obtained in vitro and in vivo with small molecule, MLN4924. Our results demonstrate a novel biological role for neddylation in regulating T cell functions in vitro and in vivo.