Browsing by Author "Kawahara, Kyoko"

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    SH3BP2 Deficiency Ameliorates Murine Systemic Lupus Erythematosus
    (MDPI, 2021-04-17) Kawahara, Kyoko; Mukai, Tomoyuki; Iseki, Masanori; Nagasu, Akiko; Nagasu, Hajime; Akagi, Takahiko; Tsuji, Shoko; Hiramatsu-Asano, Sumie; Ueki, Yasuyoshi; Ishihara, Katsuhiko; Kashihara, Naoki; Morita, Yoshitaka; Medicine, School of Medicine
    Background: The adaptor protein Src homology 3 domain-binding protein 2 (SH3BP2) is widely expressed in immune cells. It controls intracellular signaling pathways. The present study was undertaken to investigate the role of SH3BP2 in a murine systemic lupus erythematosus model. Methods: For the lupus model, we used Faslpr/lpr mice. Clinical and immunological phenotypes were compared between Faslpr/lpr and SH3BP2-deficient Faslpr/lpr mice. Splenomegaly and renal involvement were assessed. Lymphocyte subsets in the spleen were analyzed by flow cytometry. To examine the role of SH3BP2 in specific cells, B cell-specific SH3BP2-deficient lupus mice were analyzed; T cells and bone marrow-derived dendritic cells and macrophages were analyzed in vitro. Results: SH3BP2 deficiency significantly reduced lupus-like phenotypes, presented as splenomegaly, renal involvement, elevated serum anti-dsDNA antibody, and increased splenic B220+CD4−CD8− T cells. Notably, SH3BP2 deficiency in B cells did not rescue the lupus-like phenotypes. Furthermore, SH3BP2 deficiency did not substantially affect the characteristics of T cells and macrophages in vitro. Interestingly, SH3BP2 deficiency suppressed the differentiation of dendritic cells in vitro and reduced the number of dendritic cells in the spleen of the lupus-prone mice. Conclusions: SH3BP2 deficiency ameliorated lupus-like manifestations. Modulating SH3BP2 expression could thus provide a novel therapeutic approach to autoimmune diseases.
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    Sh3bp2 Gain-Of-Function Mutation Ameliorates Lupus Phenotypes in B6.MRL-Faslpr Mice
    (MDPI, 2019-04-30) Nagasu, Akiko; Mukai, Tomoyuki; Iseki, Masanori; Kawahara, Kyoko; Tsuji, Shoko; Nagasu, Hajime; Ueki, Yasuyoshi; Ishihara, Katsuhiko; Kashihara, Naoki; Morita, Yoshitaka; Biomedical Sciences and Comprehensive Care, School of Dentistry
    SH3 domain-binding protein 2 (SH3BP2) is an adaptor protein that is predominantly expressed in immune cells, and it regulates intracellular signaling. We had previously reported that a gain-of-function mutation in SH3BP2 exacerbates inflammation and bone loss in murine arthritis models. Here, we explored the involvement of SH3BP2 in a lupus model. Sh3bp2 gain-of-function (P416R knock-in; Sh3bp2KI/+) mice and lupus-prone B6.MRL-Faslpr mice were crossed to yield double-mutant (Sh3bp2KI/+Faslpr/lpr) mice. We monitored survival rates and proteinuria up to 48 weeks of age and assessed renal damage and serum anti-double-stranded DNA antibody levels. Additionally, we analyzed B and T cell subsets in lymphoid tissues by flow cytometry and determined the expression of apoptosis-related molecules in lymph nodes. Sh3bp2 gain-of-function mutation alleviated the poor survival rate, proteinuria, and glomerulosclerosis and significantly reduced serum anti-dsDNA antibody levels in Sh3bp2KI/+Faslpr/lpr mice. Additionally, B220+CD4-CD8- T cell population in lymph nodes was decreased in Sh3bp2KI/+Faslpr/lpr mice, which is possibly associated with the observed increase in cleaved caspase-3 and tumor necrosis factor levels. Sh3bp2 gain-of-function mutation ameliorated clinical and immunological phenotypes in lupus-prone mice. Our findings offer better insight into the unique immunopathological roles of SH3BP2 in autoimmune diseases.