Ps-b08-8: therapeutic strategies targeting rage improves renal outcome in lupus nephritis

Introduction: Lupus nephritis (LN) is present in 60% of patients with systemic lupus erythematosus (SLE). Despite of current development of immunosuppressant agents, LN still impairs the survival and quality of life in SLE patients. Receptor for advanced glycation endproducts (RAGE) is a multi-ligand receptor that belongs to the immunoglobulin superfamily, which is strongly associated with innate immune system. In the present study, we examined whether RAGE is involved in the development of LN. Further, we explored the therapeutic impact of DNA-aptamer directed against RAGE on lupus-related kidney injury. Methods: [Protocol 1] RAGE expression in kidneys and urinary RAGE excretion (uRAGE) were determined at 8, 12, 16, 18, 20-week-old by real-time PCR and ELISA, respectively in MRL/lpr, SLE-prone mice. [Protocol 2] LN was induced by peritoneally injecting pristane in wild type and RAGE globally knockout mice. [Protocol 3] MRL/lpr mice were subcutaneously administrated with DNA-aptamer raised against RAGE (RAGE-apt) or Control-aptamer (Ctrl-apt) for 10weeks. Results: [Protocol 1] uRAGE levels, but not urinary protein excretion, were significantly increased in 8-week-old MRL/lpr mice when compared to those in control MRL/MPJ mice, suggesting that uRAGE could be an early marker of LN.. Immunofluorescence staining demonstrated that RAGE was upregulated in distal tubules but not in glomerulus in 8-week-old mice. Glomerular RAGE expression was increased from 12-week-old with mesangial matrix expansion and formation of cellular crescents. RAGE expression was also found in endothelium and infiltrated macrophages in glomerulus while RAGE was merged with cathepsine D, a lysosomal aspartyl protease, and Rab7, a marker of late endocytosis in tubular epithelial cells. [Protocol 2] Pristane-induced increase in systolic blood pressure was reduced with improvement of renal dysfunction in RAGE knockouts. RAGE knockouts also showed less fibrosis with decrease in macrophage infiltration when compared to wild type mice in pristane-induced lupus nephritis. [Protocol 3] Administration of RAGE-apt ameliorated mesangial expansion, crescent formation, and macrophage infiltration into glomerulus in MRL/lpr mice. RAGE-apt, but not Ctrl-apt, reduced the level of pro-inflammatory cytokines gene expression including IL-6, TNF-α, and MCP-1 in renal cortex of MRL/lpr mice. Conclusion: RAGE could be involved in the pathogenesis of LN, and RAGE-DNA aptamer might be one of the promising therapeutic strategies for preventing the development of LN.