Gain-Of-Function Mutation Ameliorates Lupus Phenotypes in B6.MRL- Mice.

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. gain-of-function (P416R knock-in; ) mice and lupus-prone B6.MRL- mice were crossed to yield double-mutant () 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. gain-of-function mutation alleviated the poor survival rate, proteinuria, and glomerulosclerosis and significantly reduced serum anti-dsDNA antibody levels in mice. Additionally, B220CD4CD8 T cell population in lymph nodes was decreased in mice, which is possibly associated with the observed increase in cleaved caspase-3 and tumor necrosis factor levels. 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.