Crotalus durissus ruruimaSnake Venom and a Phospholipase A₂Isolated from This Venom Elicit Macrophages to Form Lipid Droplets and Synthesize Inflammatory Lipid Mediators

Abstract

Viper snake Crotalus durissus ruruima (Cdr) is a subspecies found in northern area of Brazil. Among the snakes of Crotalus genus subspecies, the venom of Cdr presents highest level of crotoxin, which is the major component of Crotalus snake venoms, formed by two subunits (crotapotin and a phospholipase A2 named CBr) and presents potent neurotoxic activity. Curiously, the venom of C. d. ruruima (CdrV) is better neutralized by antibothropic than by anticrotalic serum, strongly suggesting that this venom has similarities with venom of Bothrops genus snakes with regard to the ability to induce inflammation. Macrophages are cells with a central role in inflammatory and immunological responses. Upon inflammatory stimuli, these cells exhibit increased numbers of lipid droplets, which are key organelles in the synthesis and release of inflammatory mediators. However, the effects of CdrV and CBr in macrophage functions are unknown. We herein investigated the ability of CdrV and CBr to activate macrophages with focus on the formation of lipid droplets (LDs), synthesis of lipid mediators, and mechanisms involved in these effects. The involvement of LDs in PGE2 biosynthesis was also assessed. Stimulation of murine macrophages with CdrV and CBr induced an increased number of LDs and release of prostanoids (PGE2, PGD2, and TXB2). Neither CdrV nor CBr induced the expression of COX-1 and COX-2 by macrophages. LDs induced by both CdrV and CBr are associated to PLIN2 recruitment and expression and were shown to be dependent on COX-1, but not COX-2 activity. Moreover, PGE2 colocalized to CdrV- and CBr-induced LDs, revealing the role of these organelles as sites for the synthesis of prostanoids. These results evidence, for the first time, the ability of a whole snake venom to induce formation of LDs and the potential role of these organelles for the production of inflammatory mediators during envenomation by Crotalus snakes.

Crotalus Durissus Ruruima: Current Knowledge on Natural History, Medical Importance, and Clinical Toxinology

“…Indeed, rodents were the main findings in the stomach contents of C. d. ruruima and, less frequently, lizards ( Tropidurus hispidus ) ( 15 ). Unlike other populations of C. durissus , anurans ( Leptodactylus macrosternum ) were found in C. d. ruruima stomachs ( 31 ) ( Figure 2E ), which may be related to differences observed by some authors ( 6 ) in the venom of this subspecies.…”

“…The subspecies C. d. ruruima was described by Hoge in 1966 ( 3 ), based on specimens collected at Mount Roraima in Venezuela ( Figure 1 ). Among the six Brazilian rattlesnakes, the C. d. ruruima is one of the most intriguing subspecies due to its restricted distribution (limited to the northern area of the state of Roraima state in Brazil and southern Venezuela) and the unique biochemical and pharmacological properties of its venom ( 5 , 6 ).…”

“…The most recent PLA 2 isolated from C. d. ruruima is CBr (basic crotoxin), which presents its 20 amino-terminal residues identical to CB1 from C. d. terrificus venom. The CBr along with the whole venom were able to activate macrophages with focus on the formation of lipids droplets and synthesis of lipid mediators, suggesting its role on the production of inflammatory mediators during envenomings ( 6 ). Moreover, these PLA 2 s could be responsible to potentiate toxicity of venoms, according to the synergism phenomenon ( 69 ).…”

Cytosolic phospholipase A2-α participates in lipid body formation and PGE2 release in human neutrophils stimulated with an l-amino acid oxidase from Calloselasma rhodostoma venom

“…Other studies conducted with snake venoms and isolated toxins have demonstrated the production of LBs in macrophages. De Carvalho et al 64 investigated the venom capacity of Crotalus durissus ruruima and an isolated phospholipase A 2 (CBr) to activate macrophages. The researchers focused on lipid droplet formation and the synthesis of lipid mediators involved in these effects, demonstrating PLIN2 recruitment, as well as the expression and presence of PGE 2 in LBs as sites for prostatenoid synthesis.…”

Chikungunya virus entry is strongly inhibited by phospholipase A2 isolated from the venom of Crotalus durissus terrificus

“…It is characterized as a protein complex composed by two noncovalent subunits, the basic subunit phospholipase A2 (PLA2 CB ), and the acid subunit crotapotin 28 , 29 . Subsequently, PLA2 CB is approximately 14 kDa protein which possess anti-inflammatory, antiparasitic, and antibacterial properties 30 , 31 . PLA2 CB has also presented activity towards viruses such as hepacivirus C (HCV) 32 , Rocio (ROCV), Mayaro (MAYV), Dengue (DENV) and Yellow Fever (YFV) 33 , 34 .…”