Abstract
Endothelial dysfunction is common in Systemic Lupus Erythematosus (SLE), even in the absence of cardiovascular disease. Evidence suggests that impaired mitophagy contributes to SLE. Mitochondrial dysfunction is also associated with impaired endothelial function. Spermidine, a natural polyamine, stimulates mitophagy by the PINK1-parkin pathway and counters age-associated endothelial dysfunction. However, the effect of spermidine on mitophagy and vascular function in SLE has not been explored. To address this gap, 9-week-old female lupus-prone (MRL/lpr) and healthy control (MRL/MpJ) mice were randomly assigned to spermidine treatment (lpr_Spermidine and MpJ_Spermidine) for 8 weeks or as control (lpr_Control and MpJ_Control). lpr_Control mice exhibited impaired endothelial function (e.g., decreased relaxation to acetylcholine), increased markers of inflammation, and lower protein content of parkin, a mitophagy marker, in the thoracic aorta. Spermidine treatment prevented endothelial dysfunction in MRL-lpr mice. Furthermore, aortas from lpr_Spermidine mice had lower levels of inflammatory markers and higher levels of parkin. Lupus phenotypes were not affected by spermidine. Collectively, these results demonstrate the beneficial effects of spermidine treatment on endothelial function, inflammation, and mitophagy in SLE mice. These results support future studies of the beneficial effects of spermidine on endothelial dysfunction and cardiovascular disease risk in SLE.