Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0409974 (lupus)
 22,386 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Lymphoid neogenesis is associated with antibody-mediated autoimmune diseases such as Sjogren's syndrome and rheumatoid arthritis. Although systemic lupus erythematosus is the prototypical B-cell-mediated autoimmune disease, the role of lymphoid neogenesis in its pathogenesis is unknown. Intraperitoneal injection of 2,6,10,14-tetramethyl-pentadecane (TMPD, pristane) or mineral oil causes lipogranuloma formation in mice, but only TMPD-treated mice develop lupus. We report that lipogranulomas are a form of lymphoid neogenesis. Immunoperoxidase staining of lipogranulomas revealed B cells, CD4(+) T cells, and dendritic cells and in some cases organization into T- and B-cell zones. Lipogranulomas also expressed the lymphoid chemokines CCL21, CCL19, CXCL13, CXCL12, and CCL22. Expression of the type I interferon (IFN-I)-inducible genes Mx1, IRF7, IP-10, and ISG-15 was greatly increased in TMPD- versus mineral oil-induced lipogranulomas. Dendritic cells from TMPD lipogranulomas underwent activation/maturation with high CD86 and interleukin-12 expression. Magnetic bead depletion of dendritic cells markedly diminished IFN-inducible gene (Mx1) expression. We conclude that TMPD-induced lupus is associated with the formation of ectopic lymphoid tissue containing activated dendritic cells producing IFN-I and interleukin-12. In view of the increased IFN-I production in systemic lupus erythematosus, these studies suggest that IFN-I from ectopic lymphoid tissue could play a role in the pathogenesis of experimental lupus in mice.
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PMID:Type I interferon production by tertiary lymphoid tissue developing in response to 2,6,10,14-tetramethyl-pentadecane (pristane). 1656 97

Antibodies (Abs) to RNA- and DNA-containing autoantigens are characteristic of systemic lupus erythematosus (SLE). We showed previously that Toll-like receptor (TLR) 9, recognizing DNA, is required for the spontaneous generation of DNA autoantibodies, but not for the development of lupus nephritis in susceptible mice. We report that lupus-prone mice deficient in TLR7, a receptor for ssRNA, failed to generate Abs to RNA-containing antigens (Ags) such as Smith (Sm) Ag. TLR9 and TLR7 also had dramatic effects on clinical disease in lupus-prone mice. In the absence of TLR9, autoimmune disease was exacerbated, lymphocytes and plasmacytoid DCs were more activated, and serum IgG and IFN-alpha were increased. In contrast, TLR7-deficient mice had ameliorated disease, decreased lymphocyte activation, and decreased serum IgG. These findings reveal opposing inflammatory and regulatory roles for TLR7 and TLR9, despite similar tissue expression and signaling pathways. These results have important implications for TLR-directed therapy of autoimmune disease.
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PMID:Toll-like receptor 7 and TLR9 dictate autoantibody specificity and have opposing inflammatory and regulatory roles in a murine model of lupus. 1697 73

B lymphocyte chemoattractant (BLC/CXCL13) is ectopically and highly expressed in the target organs such as the thymus and kidney in aged (NZB x NZW)F1 (BWF1) mice, a murine model for SLE. Ectopic expression of BLC/CXCL13 was attributed to mature myeloid DCs infiltrating in the target organs. DCs were also increased in the peripheral blood in aged BWF1 mice and differentiated into BLC/CXCL13-producing DCs in the presence of TNF-alpha or IL-1beta, but not IFN-alpha or IFN-gamma. BLC/CXCL13 expression in mature myeloid DCs was confirmed in bone marrow derived-DCs generated in vitro in the presence of GM-CSF and TNF-alpha. B1 cells expressed higher level of CXCR5 and migrated towards BLC/CXCL13 much better than B2 cells. B1 cells failed to home to the peritoneal cavity and preferentially recruited to the target organs in aged BWF1 mice developing lupus nephritis. B1, but not B2 cells possessed a potent antigen presenting activity in allo-MLR and activated autologous thymic CD4 T cells in the presence of IL-2. CXCR5+ CD4 T cells were also increased in aged BWF1 mice and they enhanced IgG production by B1 cells in vitro. These results suggest a possible involvement of aberrant B1 cell trafficking in activation of autoreactive CD4 T cells and autoantibody production in the target organs during the development of lupus, providing a new insight for the pathogenesis of B1 cells in lupus.
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PMID:Aberrant B1 cell trafficking in a murine model for lupus. 1712 21

Innate immune receptors that recognize nucleic acids, such as TLRs and RNA helicases, are potent activators of innate immunity that have been implicated in the induction and exacerbation of autoimmunity and inflammatory arthritis. Polyriboinosine-polyribocytidylic acid sodium salt (poly(IC)) is a mimic of dsRNA and viral infection that activates TLR3 and the RNA helicases retinoic acid-induced gene-1 and melanoma differentiation-associated gene-5, and strongly induces type I IFN production. We analyzed the effects of systemic delivery of poly(IC) on the inflammatory effector phase of arthritis using the collagen Ab-induced and KRN TCR-transgenic mouse serum-induced models of immune complex-mediated experimental arthritis. Surprisingly, poly(IC) suppressed arthritis, and suppression was dependent on type I IFNs that inhibited synovial cell proliferation and inflammatory cytokine production. Administration of exogenous type I IFNs was sufficient to suppress arthritis. These results suggest a regulatory role for innate immune receptors for dsRNA in modulating inflammatory arthritis and provide additional support for an anti-inflammatory function of type I IFNs in arthritis that directly contrasts with a pathogenic role in promoting autoimmunity in systemic lupus.
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PMID:Suppression of the effector phase of inflammatory arthritis by double-stranded RNA is mediated by type I IFNs. 1727 25

T cells play an essential role in driving humoral autoimmunity in lupus. Molecules such as TRAIL exhibit strong T cell modulatory effects and are up-regulated in lupus, raising the possibility that they may influence disease severity. To address this possibility, we examined the role of TRAIL expression on pathogenic T cells in an induced model of murine lupus, the parent-into-F(1) (P-->F(1)) model of chronic graft-vs-host disease (GVHD), using wild-type or TRAIL-deficient donor T cells. Results were compared with mice undergoing suppressive acute GVHD. Although chronic GVHD mice exhibited less donor T cell TRAIL up-regulation and IFN-alpha-inducible gene expression than acute GVHD mice, donor CD4(+) T cell TRAIL expression in chronic GVHD was essential for sustaining effector CD4(+) Th cell numbers, for sustaining help to B cells, and for more severe lupus-like renal disease development. Conversely, TRAIL expression on donor CD8(+) T cells had a milder, but significant down-regulatory effect on CTL effector function, affecting the perforin/granzyme pathway and not the Fas ligand pathway. These results indicate that, in this model, T cell-expressed TRAIL exacerbates lupus by the following: 1) positively regulating CD4(+) Th cell numbers, thereby sustaining T cell help for B cells, and 2) to a lesser degree by negatively regulating perforin-mediated CD8(+) CTL killing that could potentially eliminate activated autoreactive B cells.
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PMID:T cell TRAIL promotes murine lupus by sustaining effector CD4 Th cell numbers and by inhibiting CD8 CTL activity. 1733 97

Systemic lupus erythematosus (SLE), an autoimmune disease characterized by chronic nephritis, arthritis and dermatitis, and the presence of antinuclear autoantibodies, is associated with complement factor deficiencies in the classical activation pathway. In addition, IFN-alpha seems to be a key cytokine in SLE as an activated IFN-alpha system is regularly observed in patients with SLE. Here, we demonstrate that in lupus-susceptible, complement C4-deficient mice the lack of complement results in elevated intravascular levels of apoptotic DNA. The apoptotic DNA is targeted to the splenic marginal zone where it accumulates and induces IFN-alpha. As such, we present here a unifying hypothesis for the induction of SLE that incorporates the role of complement deficiency and elevated levels of IFN-alpha.
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PMID:Elevated levels of endogenous apoptotic DNA and IFN-alpha in complement C4-deficient mice: implications for induction of systemic lupus erythematosus. 1750 29

Dendritic cell (DC) activation by nucleic acid-containing IgG complexes is implicated in systemic lupus erythematosus (SLE) pathogenesis. However, it has been difficult to definitively examine the receptors and signaling pathways by which this activation is mediated. Because mouse FcgammaRs recognize human IgG, we hypothesized that IgG from lupus patients might stimulate mouse DCs, thereby facilitating this analysis. In this study, we show that sera and purified IgG from lupus patients activate mouse DCs to produce IFN-alpha, IFN-beta, and IL-6 and up-regulate costimulatory molecules in a FcgammaR-dependent manner. This activation is only seen in sera with reactivity against ribonucleoproteins and is completely dependent on TLR7 and the presence of RNA. As anticipated, IFN regulatory factor (IRF)7 is required for IFN-alpha and IFN-beta production. Unexpectedly, however, IRF5 plays a critical role in IFN-alpha and IFN-beta production induced not only by RNA-containing immune complexes but also by conventional TLR7 and TLR9 ligands. Moreover, DC production of IL-6 induced by these stimuli is dependent on a functional type I IFNR, indicating the need for a type I IFN-dependent feedback loop in the production of inflammatory cytokines. This system may also prove useful for the study of receptors and signaling pathways used by immune complexes in other human diseases.
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PMID:Murine dendritic cell type I IFN production induced by human IgG-RNA immune complexes is IFN regulatory factor (IRF)5 and IRF7 dependent and is required for IL-6 production. 1751 36

The monocyte chemoattractant protein CCL2 is crucial for monocyte and T cell recruitment from the vascular to the extravascular compartment at sites of inflammation. CCL2 is expressed in human lupus nephritis and was shown to mediate experimental lupus; therefore, CCL2 antagonists may be beneficial for therapy. This study describes the l-enantiomeric RNA oligonucleotide mNOX-E36, a so-called Spiegelmer that binds murine CCL2 with high affinity and neutralizes its action in vitro and in vivo. The mirror image configuration of the Spiegelmer confers nuclease resistance and thus excellent biostability. mNOX-E36 does not induce type I IFN via Toll-like receptor-7 or cytosolic RNA receptors, as recently shown for certain synthetic D-RNA. Autoimmune-prone MRL(lpr/lpr) mice that were treated with a polyethylene glycol form of mNOX-E36 from weeks 14 to 24 of age showed prolonged survival associated with a robust improvement of lupus nephritis, peribronchial inflammation, and lupus-like inflammatory skin lesions. Thus, mNOX-E36-based inhibition of CCL2 represents a novel strategy for the treatment of autoimmune tissue injury, such as lupus nephritis.
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PMID:Spiegelmer inhibition of CCL2/MCP-1 ameliorates lupus nephritis in MRL-(Fas)lpr mice. 1762 18

Individuals with systemic lupus erythematosus (SLE) have a striking increase in premature atherosclerosis of unclear etiology. Accelerated endothelial cell apoptosis occurs in SLE and correlates with endothelial dysfunction. Endothelial progenitor cells (EPCs) and myelomonocytic circulating angiogenic cells (CACs) are crucial in blood vessel repair after vascular damage, and decreased levels or abnormal function of EPCs/CACs are established atherosclerosis risk factors. We investigated if vascular repair is impaired in SLE. We report that SLE patients display abnormal phenotype and function of EPCs/CACs. These abnormalities are characterized by significant decreases in the number of circulating EPCs (310 +/- 50 EPCs/mL of blood in SLE versus 639 +/- 102 in controls) and significant impairments in the capacity of EPCs/CACs to differentiate into mature ECs and synthesize adequate levels of the proangiogenic molecules vascular endothelial growth factor (VEGF) and hepatic growth factor (HGF). These abnormalities are triggered by interferon-alpha (IFN-alpha), which induces EPC and CAC apoptosis and skews myeloid cells toward nonangiogenic phenotypes. Lupus EPCs/CACs have increased IFN-alpha expression and their supernatants promote higher induction of IFN-inducible genes. Importantly, neutralization of IFN pathways restores a normal EPC/CAC phenotype in lupus. SLE is characterized by an imbalance between endothelial cell damage and repair triggered by type I IFNs, which might promote accelerated atherosclerosis.
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PMID:Interferon-alpha promotes abnormal vasculogenesis in lupus: a potential pathway for premature atherosclerosis. 1763 46

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the presence of autoantibodies and lupus nephritis. The [New Zealand black (NZB) x New Zealand white (NZW)]F1 (BWF1) mouse has been recognized as an important animal model of human SLE. The T(h)1-prone phenotype of BWF1 mice has been shown to contribute to the development of the lupus. However, the molecular basis for T(h)1 skewing in BWF1 mice has not been clarified. We noticed that IL-6, IL-12 and other proinflammatory cytokines as well as IkappaB-zeta induction were higher in mature bone marrow-derived dendritic cells (BMDCs) from NZB and BWF1 mice than those from NZW mice. The expression of an IFN-inducible gene Ifi202, a candidate gene for lupus, was almost undetectable in NZW BMDCs. Thus, we hypothesized that Ifi202 is involved in elevated IL-12 production from BWF1 BMDCs. Overexpression of Ifi202 enhanced the LPS-induced IkappaB-zeta, IL-12p40 and NF-kappaB promoter activities, while anti-sense (AS) RNA against Ifi202 strongly suppressed them in a monocytic cell line, RAW 264.7. Furthermore, overexpression of Ifi202 enhanced LPS-induced IL-12p40 and IkappaB-zeta mRNA induction while Ifi202 AS RNA suppressed these in RAW 264.7 cells. In addition, forced expression of Ifi202 enhanced IL-12p40 mRNA induction in NZW BMDCs. Thus, Ifi202 is an important NF-kappaB activator in DCs and involved in IL-12 production, which may account for a T(h)1-prone phenotype of BWF1 mice.
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PMID:Ifi202, an IFN-inducible candidate gene for lupus susceptibility in NZB/W F1 mice, is a positive regulator for NF-kappaB activation in dendritic cells. 1770 89


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