Atsushi Sadanaga

Membranous Glomerulonephritis Development with Th2-Type Immune Deviations in MRL/lpr Mice Deficient for IL-27 Receptor (WSX-1)

MRL/lpr mice develop spontaneous glomerulonephritis that is essentially identical with diffuse proliferative glomerulonephritis (World Health Organization class IV) in human lupus nephritis. Lupus nephritis is one of the most serious complications of systemic lupus erythematosus. Diffuse proliferative glomerulonephritis is associated with autoimmune responses dominated by Th1 cells producing high levels of IFN-γ. The initial mounting of Th1 responses depends on the function of the WSX-1 gene, which encodes a subunit of the IL-27R with homology to IL-12R. In mice deficient for the WSX-1 gene, proper Th1 differentiation was impaired and abnormal Th2 skewing was observed during infection with some intracellular pathogens. Disruption of the WSX-1 gene dramatically changed the pathophysiology of glomerulonephritis developing in MRL/lpr mice. WSX-1−/− MRL/lpr mice developed disease resembling human membranous glomerulonephritis (World Health Organization class V) with a predominance of IgG1 in glomerular deposits, accompanied by increased IgG1 and IgE in the sera. T cells in WSX-1−/− MRL/lpr mice displayed significantly reduced IFN-γ production along with elevated IL-4 expression. Loss of WSX-1 thus favors Th2-type autoimmune responses, suggesting that the Th1/Th2 balance may be a pivotal determinant of human lupus nephritis development.

Amelioration of human lupus-like phenotypes in MRL/lpr mice by overexpression of interleukin 27 receptor α (WSX-1)

Objective: In the present work, we investigate the role of interleukin (IL)27/IL27 receptor α (Rα) (WSX-1) in the development of autoimmune disorders in the MRL/lpr mouse, which is considered as an experimental model of systemic lupus erythaematosus (SLE) in humans. Methods: We generated two strains of WSX-1 transgenic mice in the MRL/lpr background with different expression levels of WSX-1, and investigated the effect of WSX-1 overexpression on survival, glomerulonephritis and immunological properties. Results: In comparison with wild type (WT) MRL/lpr and transgenic (Tg) low (TgL) mice, Tg high (TgH) mice exhibited a prolonged lifespan and no apparent development of autoimmune nephritis. Production of anti-dsDNA antibody and total IgG and IgG2a were significantly lower in TgH mice than those of TgL and WT mice. The expressed amounts of interferon (IFN)γ and IL4 mRNA by CD4+ T cells from Tg mice decreased in a dose-dependent fashion. CD4+ splenic lymphocytes in TgH mice were more subject to the IL27-mediated suppression of cytokine production. In vitro stimulation of CD4+ T cells by IL27 resulted in over phosphorylation of STAT3 in TgH cells than in WT cells. Conclusion: WSX-1 overexpression in the MRL/lpr background rendered the autoimmune prone mice protected from the development of autoimmune diseases. Our results suggest that IL27 signalling may be a therapeutic target against autoimmune diseases, including human SLE.

Amelioration of human lupus-like phenotypes in MRL/lpr mice by overexpression of IL-27Rα (WSX-1)

Objective: In the present work, we investigate the role of interleukin (IL)27/IL27 receptor α (Rα) (WSX-1) in the development of autoimmune disorders in the MRL/lpr mouse, which is considered as an experimental model of systemic lupus erythaematosus (SLE) in humans. Methods: We generated two strains of WSX-1 transgenic mice in the MRL/lpr background with different expression levels of WSX-1, and investigated the effect of WSX-1 overexpression on survival, glomerulonephritis and immunological properties. Results: In comparison with wild type (WT) MRL/lpr and transgenic (Tg) low (TgL) mice, Tg high (TgH) mice exhibited a prolonged lifespan and no apparent development of autoimmune nephritis. Production of anti-dsDNA antibody and total IgG and IgG2a were significantly lower in TgH mice than those of TgL and WT mice. The expressed amounts of interferon (IFN)γ and IL4 mRNA by CD4+ T cells from Tg mice decreased in a dose-dependent fashion. CD4+ splenic lymphocytes in TgH mice were more subject to the IL27-mediated suppression of cytokine production. In vitro stimulation of CD4+ T cells by IL27 resulted in over phosphorylation of STAT3 in TgH cells than in WT cells. Conclusion: WSX-1 overexpression in the MRL/lpr background rendered the autoimmune prone mice protected from the development of autoimmune diseases. Our results suggest that IL27 signalling may be a therapeutic target against autoimmune diseases, including human SLE.

Promoter polymorphisms in the IRF3 gene confer protection against systemic lupus erythematosus

In order to identify a novel candidate gene in systemic lupus erythematosus (SLE), we analysed a panel of six genes encoding molecules involved in the type I interferon (IFN) system. We first identified variants in the five genes related to type I IFN pathway by sequencing. Genotyping of a panel of eight selected single-nucleotide polymorphisms (SNPs) in six candidate genes (TLR9, MYD88, IRF3, IRF7, IFNB1, IFNA17) was performed in 137 patients with SLE and matched with 152 healthy controls using polymerase chain reaction-restriction fragment length polymorphism analysis. In functional assay, quantitative real-time polymerase chain reaction was performed to assess constitutive IRF3 mRNA expression in peripheral blood mononuclear cells from healthy subjects with different IRF3 promoter haplotypes. Among eight SNPs genotyped, an IRF3 SNP at –925 was found to be associated with SLE after correction for multiple tests (corrected P = 0.016). Of total five IRF3 SNPs genotyped, the promoter IRF3 SNPs –925A/G and –776C/T showed the most significant association with SLE. With regard to –925A/G, the frequency of GG genotype was significantly decreased among SLE patients compared with the control group (1.5% vs. 9.9%; χ2 = 10.0, P = 0.0015, odds ratio 0.12, 95% confidence interval 0.027–0.554). Our experimental data indicated that constitutive IRF3 mRNA expression was significantly lower in cells carrying the minor G-T/G-T haplotype pair compared with those carrying the major A-C haplotype. In conclusion, we showed that the promoter SNPs of the IRF3 gene were significantly associated with resistance against SLE.

Deficiency in EBV-induced gene 3 (EBI3) in MRL/lpr mice results in pathological alteration of autoimmune glomerulonephritis and sialadenitis

MRL/lpr mice develop a systemic autoimmune disease that is reminiscent of systemic lupus erythematosus (SLE) and Sjögren’s syndrome in humans. To investigate the role of IL-27 in the development of autoimmune disorders in MRL/lpr mice, we disrupted the EBV-induced gene 3 (EBI3), which is a subunit of IL-27. Consequently, the pathophysiology of glomerulonephritis and sialadenitis, which develops in MRL/lpr mice, was drastically changed. EBI3−/− MRL/lpr mice developed disease that resembles human membranous glomerulonephritis (MGN), not diffuse proliferative glomerulonephritis (DPGN), with a predominance of IgG1 in glomerular deposits, and different type sialadenitis from Sjögren’s syndrome, with IgG1 producing plasma cell infiltration in salivary glands, accompanied by increased IgG1 and IgE in the sera. T cells in these mice displayed significantly reduced IFN-γ production along with elevated IL-4 expression. Loss of EBI3 thus favors Th2-type autoimmune responses, suggesting that the Th1/Th2 balance may be a pivotal determinant of phenotypes of human autoimmune diseases.

Absence of association between the MCP-1 gene polymorphism and histological phenotype of lupus nephritis.

Lupus nephritis presents two polar histological patterns, diffuse proliferative glomerulonephritis (DPGN) and membranous glomerulonephritis (MGN). In the kidney tissue of DPGN, numerous mononuclearcells were seen in the interstitium and glomeruli; on the other hand in MGN, infiltrating cells were less frequent. Monocyte chemoattractantprotein-1 (MCP-1) is a potent chemoattractantfor monocytes, T-cells, and natural killer cells. In this study we assessed the significance of the MCP-1 gene in determination of the histological phenotype in lupus nephritis. There was no association between the risk of DPGN and the MCP-1 gene genotype.

Acquired hemophilia in a patient with systemic lupus erythematosus: a case report and literature review.

We report the case of a 38-year-old female patient with systemic lupus erythematosus (SLE) who developed acquired hemophilia caused by factor VIII (FVIII) inhibitors. She manifested spontaneous bleeding symptoms such as ecchymoses and hematuria. Laboratory findings showed an isolated prolongation of the activated partial thromboplastin time, reduced FVIII activity, and a high titer of FVIII inhibitors. She was successfully treated with oral predonisolone and cyclosporine in combination with steroid and cyclophosphamide pulse therapy.

Association between IFNA genotype and the risk of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is characterized by multisystem inflammation and production of autoantibodies, which can generate immune complexes and may cause tissue damage through the recognition of an autoantigen. Although many factors have been proposed, such as genetic factors, environmental factors, hormonal action, viruses, and dysregulation of cytokine production, the cause of this disease is not well understood. It has been reported that the levels of interferon (IFN)-α in the sera of some SLE patients are elevated and that IFN-α induces maturation of monocytes into highly active antigen-presenting dendritic cells (DCs). We analyzed the association between IFN-α genotype and the risk of SLE to clarify whether IFN-α plays a central role in susceptibility to SLE. The results showed that no IFN-α genotype was significantly associated with the risk of SLE.