Oleocanthal supplemented diet improves renal damage and endothelial dysfunction in pristane-induced systemic lupus erythematosus in mice

Systemic lupus erythematosus (SLE) is a multiorgan disorder with a deregulated immune-inflammatory response. Nutritional therapy has been considered a promising approach to SLE management. Oleocanthal (OLE), the main extra virgin olive oil (EVOO)-derived secoiridoid, has shown to regulate the immune-inflammatory response in various disease contexts; however, its possible beneficial effects on SLE remain unclear. This study sought to evaluate the effects of OLE enriched diet on renal damage and aortic endothelial dysfunction in murine pristane-induced SLE, focusing on the action mechanisms and signaling pathways involved. BALB/c mice were injected with pristane and fed with OLE supplemented diet (0.01 % (w/w)) for six months. Levels of cytokines were measured by ELISA in lipopolysaccharide (LPS)-stimulated peritoneal macrophages and splenocytes. Presence of immunoglobulin G (IgG) and IgM immune complexes were examined by immunofluorescence and immunohistochemistry. Thoracic aortas were used to evaluate endothelial dysfunction. Western blotting was employed to detect signaling pathways and oxidative-inflammatory-related mediators. Dietary OLE supplementation reduced Th1/Th17 pro-inflammatory cytokines production and alleviated renal damage by decreasing immunoglobulin complexes deposition, and inflammation-mediating enzymes expression. The mechanisms underlying these protective effects could be related to the regulation of nuclear factor erythroid 2-related factor 2/Haem oxygenase 1 (Nrf-2/HO-1), mitogen-activated protein kinases (MAPKs), signal transducer and transcription activator of transcription (STAT-3), inflammasome and, nuclear factor kappa B (NF-κB) signaling pathways. Also, dietary OLE improved aortic endothelial dysfunction and vascular reactivity, normalizing endothelial nitric oxide synthase (eNOS) uncoupling, and NADPH oxidase-1 (NOX-1) overexpression. This study shows the immunomodulatory effects of OLE in an in vivo model of SLE by improving renal damage and regulating aortic endothelial dysfunction. These preliminary results provide OLE as a new therapeutic strategy in SLE management.