Pathologic properties of SOD3 variant R213G in the cardiovascular system through the altered neutrophils function

The SOD3 variant, SOD3(R213G), results from substitution of arginine to glycine at amino acid 213 (R213G) in its heparin binding domain (HBD) and is a common genetic variant, reported to be associated with ischemic heart disease. However, little is understood about the role of SOD3(R213G) in innate immune function, and how it leads to dysfunction of the cardiovascular system. We observed pathologic changes in SOD3(R213G) transgenic (Tg) mice, including cystic medial degeneration of the aorta, heart inflammation, and increased circulating and organ infiltrating neutrophils. Interestingly, SOD3(R213G) altered the profile of SOD3 interacting proteins in neutrophils in response to G-CSF. Unexpectedly, we found that G-CSF mediated tyrosine phosphatase, SH-PTP1 was down-regulated in the neutrophils of SOD3(R213G) overexpressing mice. These effects were recovered by reconstitution with Wt SOD3 expressing bone marrow cells. Overall, our study reveals that SOD3(R213G) plays a crucial role in the function of the cardiovascular system by controlling innate immune response and signaling. These results suggest that reconstitution with SOD3 expressing bone marrow cells may be a therapeutic strategy to treat SOD3(R213G) mediated diseases.