Project description:Cooperative role of Lymphotoxin β Receptor and Tumor Necrosis Factor Receptor p55 in murine liver regeneration (PHx Control vs Enbrel)
Project description:Systemic lupus erythematosus (SLE) is an autoimmune disorder with systemic inflammation, autoantibody accumulation and organ damage. The abnormalities of double-negative (DN) T cells are considered as an important commander of SLE. Neddylation, an important type of protein post-translational modification (PTM), has been well-proved to regulate T cell-mediated immune response. However, the function of neddylation in SLE remains largely unexplored. Here, we reported that neddylation inactivation with MLN4924 or genetic abrogation of Ube2m in T cells prevented SLE development for decreased DN T cell accumulation. Further investigations revealed that inactivation of neddylation blocked Bim ubiquitination degradation and maintained Bim level in DN T cells, contributing to the apoptosis of the accumulated DN T cells for Fas mutation. Then double knockout (KO) lupus-prone mice (Ube2m-/-Bim-/-lpr) were generated and results showed that loss of Bim interrupted the improvement of DN T cell apoptosis and the consequential relieved lupus symptoms for Ube2m KO. Our findings identified that neddylation inactivation promoted Bim-mediated apoptosis of DN T cells and prevented lupus progress. Clinically, we also found the percentages of DN T cells were improved accompanied with reduced apoptosis of DN T cells in SLE patients. Moreover, the neddylation of Cullin1 was higher while Bim level was decreased in SLE patients compared with healthy control. Meantime, the inhibition of neddylation induced Bim-dependent apoptosis of DN T cells isolated from SLE patients. Together, these findings provide the first evidence of the neddylation role in lupus development, suggesting a novel therapeutic strategy for lupus.
Project description:Type I interferons are critical anti-viral cytokines during virus infections and have also been implicated in the pathogenesis of systemic lupus erythematosus (SLE). The secretion of type I interferon of pDCs is modulated by Siglec-H, a DAP12 associated receptor on pDCs. We showed that Siglec-H deficient pDCs produce more of the type I interferon IFN-α in vitro and that Siglec-H ko mice produce more IFN-α after murine cytomegalovirus (mCMV) infection in vivo, leading to efficient clearance of the virus. Furthermore, ageing Siglec-H ko mice showed a mild form of systemic autoimmunity. In contrast, Siglec-H ko mice developed a severe form of systemic lupus-like autoimmune disease with strong kidney nephritis several weeks after a single mCMV infection. This induction of systemic autoimmune disease after virus infection in Siglec-H ko mice was accompanied by a type I interferon signature and fully dependent on type I interferon signaling. These results show that Siglec-H normally serves as modulator of type I interferon responses after infection with a persistent virus and thereby prevents induction of autoimmune disease. For microarray experiments gene expression profiles of total splenic cells from two wt and Siglec-H ko mice 26 weeks after infection with luciferase expressing murine Cytomegalovirus (5x105 pfu) or from two uninfected wt and Siglec-H ko control mice were analyzed
Project description:Type I interferons are critical anti-viral cytokines during virus infections and have also been implicated in the pathogenesis of systemic lupus erythematosus (SLE). The secretion of type I interferon of pDCs is modulated by Siglec-H, a DAP12 associated receptor on pDCs. We showed that Siglec-H deficient pDCs produce more of the type I interferon IFN-α in vitro and that Siglec-H ko mice produce more IFN-α after murine cytomegalovirus (mCMV) infection in vivo, leading to efficient clearance of the virus. Furthermore, ageing Siglec-H ko mice showed a mild form of systemic autoimmunity. In contrast, Siglec-H ko mice developed a severe form of systemic lupus-like autoimmune disease with strong kidney nephritis several weeks after a single mCMV infection. This induction of systemic autoimmune disease after virus infection in Siglec-H ko mice was accompanied by a type I interferon signature and fully dependent on type I interferon signaling. These results show that Siglec-H normally serves as modulator of type I interferon responses after infection with a persistent virus and thereby prevents induction of autoimmune disease.
Project description:Psip1/p75 binds to Hox genes and colocalizes with Mll1 and in Psip1 KO MEFs Mll1 occupancy is reduced over Hox genes Psip1/p75 ChIP using A300-848 abtibody (recognises p75 isoform of Psip1) and Mll1 ChIP from WT and Psip1 KO MEFs ChIP-chip
Project description:Paneth Cells (PCs) are secretory cells located in the crypts of Lieberkühn of the small intestine. They produce antimicrobial peptides (AMPs) and are thought to keep the microbiome under control. The cytokine TNF, which functions mainly via its TNF receptor 1 (TNFR1 or P55), is a driving force in many inflammatory bowel disease (IBD) patients, but its impact on PCs is poorly known. We have generated PC-specific P55 knockout mice (P55Paneth KO) and found that these mice are protected against lethal TNF-induced systemic inflammatory response syndrome (SIRS). The impact of TNF on PCs is characterized by morphological changes and by intestinal bacterial translocation into organs, such as liver, in which these bacteria induce expression of numerous genes, associated with typical sepsis signatures. The presence of these bacteria cause lethality of the mice. Based on bulk RNA-SEQ on pure PCs, P55 signaling stimulated mainly a type-I IFN response in the PCs, which drives the bacterial translocation and lethality via IFNAR1. Interestingly, based on ER stress reporter mice, PCs constitutively have high amounts of spliced XBP1 (XBP1s) protein, presumably to support their secretion of AMPs, and TNF eradicates this XBP1s production, leading to failure of the unfolded protein response (UPR). This causes reduced antimicrobial activity in PCs, in a P55 and IFNAR1-dependent way. Our data suggest a novel axis induced by TNF in PCs, leading to interferon-induced UPR failure causing lethal bacterial translocation to the liver (and other organs)