The Role of Extracellular NF-E2 as a DAMP Released During Acrolein Induced Renal Fibrosis

This is a three year project that examined the effects of an environmental toxin, acrolein, on human neutrophil activation and on human renal tubular cells (HK-11). In the first year, I demonstrated that acrolein regulated neutrophil apoptosis. In the second year I demonstrated that acrolein stimulated renal cell death and promoted renal fibrosis. Importantly, I identified a novel regulator of renal fibrosis called nuclear factor erythroid-derived protein 2 (NF-E2) in HK-11 cells. Acrolein exposure decreased NF-E2 expression in HK-11 cells as NF-E2 was secreted outside the cells. Danger associated molecular patterns (DAMPs) are proteins released by dying renal cells and are known to play a role in activating and recruiting inflammatory cells and exacerbating renal injury. This year we identified NF-E2 as a DAMP. Acrolein-treated HK-11cell supernatants stimulated pro-survival ERK phosphorylation (pERK) and promoted neutrophil survival by inhibiting caspase-3 activation. Depletion of NF-E2 from acrolein-treated HK-11 supernatants with anti-NF-E2 antibody inhibited pERK, stimulated pro-apoptotic p38 MAPK phosphorylation and promoted human neutrophil apoptosis by activating caspase-3. NF-E2-containing HK-11 cell supernatants stimulated actin polymerization and chemotaxis in neutrophils. Thus, anti-NF-E2 antibody may serve as a therapeutic option to reduce inflammation and ameliorate acrolein-induced renal toxicity.