Crotamine stimulates phagocytic activity by inducing nitric oxide and TNF-α via p38 and NFκ-B signaling in RAW 264.7 macrophages.

Crotamine is a peptide toxin found in the venom of the rattlesnake Crotalus durissus terrificus and has antiproliferative, antimicrobial, and antifungal activities. Herein, we show that crotamine dose-dependently induced macrophage phagocytic and cytostatic activity by the induction of nitric oxide (NO) and tumor necrosis factor-alpha (TNF-α). Moreover, the crotamineinduced expression of iNOS and TNF-α is mediated through the phosphorylation of p38 and the NF-κB signaling cascade in macrophages. Notably, pretreatment with SB203580 (a p38-specific inhibitor) or BAY 11-7082 (an NF-κB inhibitor) inhibited crotamine-induced NO production and macrophage phagocytic and cytotoxic activity. Our results show for the first time that crotamine stimulates macrophage phagocytic and cytostatic activity by induction of NO and TNF-α via the p38 and NF-κB signaling pathways and suggest that crotamine may be a useful therapeutic agent for the treatment of inflammatory disease. [BMB Reports 2016; 49(3): 185-190].