Differential transcript profile of inhibitors with potential anti-venom role in the liver of juvenile and adultBothrops jararacasnake

Abstract

BackgroundSnakes belonging to the Bothrops genus are vastly distributed in Central and South America and are responsible for most cases of reported snake bites in Latin America. The clinical manifestations of the envenomation caused by this genus are due to three major activities—proteolytic, hemorrhagic and coagulant—mediated by metalloproteinases, serine proteinases, phospholipases A2 and other toxic compounds present in snake venom. Interestingly, it was observed that snakes are resistant to the toxic effects of its own and other snake’s venoms. This natural immunity may occur due the absence of toxin target or the presence of molecules in the snake plasma able to neutralize such toxins.MethodsIn order to identify anti-venom molecules, we construct a cDNA library from the liver of B. jararaca snakes. Moreover, we analyzed the expression profile of four molecules—the already known anti-hemorrhagic factor Bj46a, one gamma-phospholipase A2 inhibitor, one inter-alpha inhibitor and one C1 plasma protease inhibitor—in the liver of juvenile and adult snakes by qPCR.ResultsThe results revealed a 30-fold increase of gamma-phospholipase A2 inhibitor and a minor increase of the inter-alpha inhibitor (5-fold) and of the C1 inhibitor (3-fold) in adults. However, the Bj46a factor seems to be equally transcribed in adults and juveniles.DiscussionThe results suggest the up-regulation of different inhibitors observed in the adult snakes might be a physiological adaptation to the recurrent contact with their own and even other snake’s venoms throughout its lifespan. This is the first comparative analysis of ontogenetic variation of expression profiles of plasmatic proteins with potential anti-venom activities of the venomous snake B. jararaca. Furthermore, the present data contributes to the understanding of the natural resistance described in these snakes.

Purification and characterization of the first γ-phospholipase inhibitor (γPLI) from Bothrops jararaca snake serum

“…After two chromatographic steps, γBjPLI was isolated with a recovery of 1% of the serum proteins applied initially, which was lower than that recovered by purification of γCdcPLI (2.60%) from plasma of Crotalus durissus collineatus , possibly due to methodological differences and biological characteristics [ 34 ]. Variation in the levels of inhibitors of venom components found in snake plasmas is still not well understood, and may be a physiological response of the snakes to repeatedly contact with the venom or be under a genetically programmed control [ 54 ]. It is known that newborns of Clelia clelia (an ophiophagus snake), even without any contact with venom, have antihemorrhagic properties in serum [ 55 ].…”

“…On the other hand, recently, a study described the clear ontogenetic difference of inhibitors expression by qPCR profile analysis, in which γ-PLI had an up-regulation around 30-fold in adults in relation to juvenile of B . jararaca specimens [ 54 ]. Also, Kinkawa et al demonstrated that the gene expression of α-PLI and β-PLI in Gloydius brevicaudus liver is increased by the intramuscular injection of the PLA 2 derived from its own venom [ 56 ].…”

Comparative compositional and functional analyses of Bothrops moojeni specimens reveal several individual variations

“…However, several concepts were further established in the 19 th century, including the one that the natural immunity is not species-specific [23] and can be found in other animals, such as several species of opossums, squirrels, mongooses, and hedgehogs [24–27]. This resistance is generally assigned to mutations in the gene encoding the target of the venom toxin, resulting in an insensitive target, and/or to the presence of neutralizing factors in the blood of resistant animals [28–30].…”

“…In addition, inhibitors from B . jararaca plasma and serum have been identified, isolated, and characterized, including phospholipase A 2 inhibitors (PLIs) [33], a thrombin inhibitor that also binds to thrombin-like venom toxins [34,35], and a metalloproteinase inhibitor (the anti-hemorrhagic factor Bj46a) [30]. It is believed that these molecules play an important physiologic role in the protection mechanism against self-envenomation and envenomation by other snake species.…”

Genetic characterization of potential venom resistance proteins in California ground squirrels (Otospermophilus beecheyi) using transcriptome analyses

“…Second, resistance gene sequences are likely to show high levels of nonsynonymous variants among the different populations due to reciprocal population‐specific coevolutionary interactions with venom proteins in rattlesnakes (Feldman et al, 2009; Jansa & Voss, 2011). Third, we would also expect venom resistance proteins to show high levels of transcription in the liver, as it is a center for detoxification and secretion of serum proteins (Gomes et al, 2017; Kalsheker, 1989; Rocha et al, 2002). For example, α‐1‐antitrypsin was shown to be under positive selection (Gibbs et al, 2020) and is a protease inhibitor that is transcribed in the liver (Guttman et al, 2015; Kalsheker, 1989).…”