Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0024141 (systemic lupus erythematosus)
 44,322 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Transmembrane activator and calcium-modulating cyclophilin ligand interactor (TACI) is one of the receptors of B cell activating factor of the tumor necrosis factor family (BAFF) and a proliferation-inducing ligand (APRIL). TACI is a regulator in the immune responses. TACI inhibits B cell expansion and promotes the differentiation and survival of plasma cells. The mechanisms underlying these effects probably involve changed expressions of some crucial molecules, such as B lymphocyte induced maturation protein-1 (Blimp-1) and inducible T-cell costimulator ligand (ICOSL) in B cells and/or plasma cells. However, abnormal TACI signaling may relate to autoimmune disorders. Common variable immune deficiency (CVID) patients with heterozygous mutations in TACI alleles increase susceptibility to autoimmune diseases. Taci (-/-) mice and BAFF transgenic mice both develop signs of human SLE. These findings that indicate inappropriate levels of TACI signaling may disrupt immune system balance, thereby promoting the development of autoimmune diseases. In this review, we summarize the basic characteristics of the TACI ligands BAFF and APRIL, and detail the research findings on the role of TACI in humoral immunity. We also discuss the possible mechanisms underlying the susceptibility of CVID patients with TACI mutations to autoimmune diseases and the role of TACI in the pathogenesis of SLE.
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PMID:Effect of TACI signaling on humoral immunity and autoimmune diseases. 2586 27

Autoantibodies contribute to the development of systemic lupus erythematosus (SLE). APRIL (a proliferation-inducing ligand), a member of the TNF superfamily, regulates plasma-cell survival and binds to TACI (transmembrane activator CAML interactor) and BCMA (B-cell maturation antigen). We previously showed that APRIL blockade delayed disease onset in lupus-prone mice. In order to evaluate the role of APRIL receptors in the development of SLE, APRIL, TACI, BCMA, or double TACI.BCMA null mutations were introduced into the Nba2.Yaa (Y-linked autoimmune acceleration) spontaneous lupus mouse model. Mortality as a consequence of glomerulonephritis (GN) was reduced in Nba2.APRIL-/- .Yaa, Nba2.TACI-/- .Yaa and double-KO mice compared with Nba2.Yaa mice and correlated with lower levels of circulating antibodies, while splenic populations remained unchanged. In contrast, the appearance of symptoms was accelerated in BCMA-deficient mice, in which TACI signaling was increased. Finally, lupus-prone mice deficient for the APRIL-TACI axis produced less pathogenic antibodies and developed less GN. Disease reduction was attributed to impaired T-independent type 2 responses when the APRIL-TACI signaling axis was disrupted. Collectively, our results have identified and confirmed APRIL as a new target involved in B-cell activation, in the maintenance of plasma cell survival and subsequent increased autoantibody production that sustains lupus development in mice.
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PMID:TACI-dependent APRIL signaling maintains autoreactive B cells in a mouse model of systemic lupus erythematosus. 2826 97

B cells are known to promote the pathogenesis of systemic lupus erythematosus (SLE) via the production of pathogenic anti-nuclear antibodies. However, the signals required for autoreactive B cell activation and the immune mechanisms whereby B cells impact lupus nephritis pathology remain poorly understood. The B cell survival cytokine B cell activating factor of the TNF Family (BAFF) has been implicated in the pathogenesis of SLE and lupus nephritis in both animal models and human clinical studies. Although the BAFF receptor has been predicted to be the primary BAFF family receptor responsible for BAFF-driven humoral autoimmunity, in the current study we identify a critical role for signals downstream of Transmembrane Activator and CAML Interactor (TACI) in BAFF-dependent lupus nephritis. Whereas transgenic mice overexpressing BAFF develop progressive membranoproliferative glomerulonephritis, albuminuria and renal dysfunction, TACI deletion in BAFF-transgenic mice provided long-term (about 1 year) protection from renal disease. Surprisingly, disease protection in this context was not explained by complete loss of glomerular immune complex deposits. Rather, TACI deletion specifically reduced endocapillary, but not mesangial, immune deposits. Notably, although excess BAFF promoted widespread breaks in B cell tolerance, BAFF-transgenic antibodies were enriched for RNA- relative to DNA-associated autoantigen reactivity. These RNA-associated autoantibody specificities were specifically reduced by TACI or Toll-like receptor 7 deletion. Thus, our study provides important insights into the autoantibody specificities driving proliferative lupus nephritis, and suggests that TACI inhibition may be novel and effective treatment strategy in lupus nephritis.
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PMID:TACI deletion protects against progressive murine lupus nephritis induced by BAFF overexpression. 2990 58