Journal of immunology (Baltimore, Md. : 1950) 2012 Apr 15;188(8):3820-8. Epub 2012 Mar 12.
Staehli, F; Ludigs, K; Heinz, LX; Seguín-Estévez, Q; Ferrero, I; Braun, M; Schroder, K; Rebsamen, M; Tardivel, A; Mattmann, C; Macdonald, HR; Romero, P; Reith, W; Guarda, G; Tschopp, J
Department of Biochemistry, University of Lausanne, 1066 Epalinges, Switzerland.
Nucleotide-binding oligomerization domain-like receptors (NLRs) are intracellular proteins involved in innate-driven inflammatory responses. The function of the family member NLR caspase recruitment domain containing protein 5 (NLRC5) remains a matter of debate, particularly with respect to NF-κB activation, type I IFN, and MHC I expression. To address the role of NLRC5, we generated Nlrc5-deficient mice (Nlrc5(Δ/Δ)). In this article we show that these animals exhibit slightly decreased CD8(+) T cell percentages, a phenotype compatible with deregulated MHC I expression. Of interest, NLRC5 ablation only mildly affected MHC I expression on APCs and, accordingly, Nlrc5(Δ/Δ) macrophages efficiently primed CD8(+) T cells. In contrast, NLRC5 deficiency dramatically impaired basal expression of MHC I in T, NKT, and NK lymphocytes. NLRC5 was sufficient to induce MHC I expression in a human lymphoid cell line, requiring both caspase recruitment and LRR domains. Moreover, endogenous NLRC5 localized to the nucleus and occupied the proximal promoter region of H-2 genes. Consistent with downregulated MHC I expression, the elimination of Nlrc5(Δ/Δ) lymphocytes by cytotoxic T cells was markedly reduced and, in addition, we observed low NLRC5 expression in several murine and human lymphoid-derived tumor cell lines. Hence, loss of NLRC5 expression represents an advantage for evading CD8(+) T cell-mediated elimination by downmodulation of MHC I levels-a mechanism that may be exploited by transformed cells. Our data show that NLRC5 acts as a key transcriptional regulator of MHC I in lymphocytes and support an essential role for NLRs in directing not only innate but also adaptive immune responses.
The team at Ozgene has over two decades of experience creating customised knockout and knock-in mice for pivotal medical research globally. Over 300 scientific publications are based on research using Ozgene mice.