A(1-7) Reduces Pathologies Associated with SLE in MRL-lpr Mice

Abstract Patients with Systemic Lupus Erythematosus (SLE) suffer from a chronic inflammatory autoimmune disease that causes damage to various organ systems. Even with the array of current treatments, patients with lupus are still in need of effective therapies to treat this complex, multi-system disease. Recent studies of the Renin Angiotensin System (RAS), widely known for its role in blood pressure regulation, have uncovered immunomodulatory effects. One of the more recently discovered components of RAS, angiotensin (1-7) [A(1-7)], is a bioactive peptides that affects various systems. In our study, MRL-lpr mice were treated daily with saline or A(1-7) for 6 weeks starting at 8 weeks of age. Proteinuria was monitored throughout the duration of the study. MRL-lpr mice treated with saline had higher levels of proteinuria compared to the MRL/MpJ- control mice, and A(1-7) treated MRL-lpr mice. A glomerulonephritis score revealed that the MRL-lpr mice had significant glomerular pathologies compared to MRL-MpJ mice of the same age. A(1-7) treatment significantly reduced the glomerular pathologies in the MRL-lpr mice. Treatment with A(1-7) reduced the size of both inguinal and axillary lymph nodes in MRl-lpr mice, and levels of anti-dsDNA IgG compared to the saline treated MRL-lpr mice. Treatment with A(1-7) also significantly reduced the severity of cutaneous pathologies resulting in only mild inflammation and hair loss compared to the saline treated MRL-lpr mice. Daily systemic treatment with A(1-7) significantly ameliorated disease in one of the most severe mouse models of SLE, making Mas agonists a potential target for future SLE therapies.