Crotalus durissus terrificus snake venom activates 3T3-L1 preadipocytes to release PGE, which depends on COX-2 expression and is modulated by PGE EP2 receptor.

Snakebites are a worldwide public health problem with high-cost treatment in many countries. Crotalus genus snakes, commonly known as rattlesnakes, cause the most lethal snakebites in Brazil. Crotalus ssp envenomation is characterised by systemic neurotoxicity, myotoxicity, renal failure and minor local effects. Despite the knowledge of envenomation's pathogenesis, the impact of Crotalus venom on adipose tissue (AT) cells is unknown. AT is an endocrine organ capable of releasing diverse immunomodulatory molecules, including prostaglandin E (PGE). Herein, we investigated the effects of Crotalus durissus terrificus venom (CdtV) on preadipocytes in vitro, focussing on the release of PGE and mechanisms involved. CdtV (5 and 10 μg/mL) induced a marked release of PGE by preadipocytes (3-24 h) compared to controls. Pre-treatment of cells with SC-560 or NS-398, selective inhibitors for cyclooxygenase (COX)-1 and COX-2 enzymes, respectively, decreased CdtV-induced PGE release after 24 h. CdtV (1 and 10 μg/mL) did not change COX-1 protein expression by preadipocytes, but induced COX-2 protein expression at all time intervals evaluated. Pre-treating preadipocytes with AH6809, an inhibitor of the PGE EP2 receptor, significantly increased the CdtV-induced PGE release. EP1, EP3, or EP4 receptor antagonists did not change the CdtV-induced PGE release. Additionally, CdtV did not alter the EP2 receptor protein expression in preadipocytes. These findings demonstrate that CdtV activates preadipocytes to produce PGE via COX-1 activation and COX-2 protein expression and PGE triggers a negative feedback loop via EP2 for its own production. These results highlight AT as another target for CdtV that may contribute to envenomation.