Mechanisms of Vascular Damage by Hemorrhagic Snake Venom Metalloproteinases: Tissue Distribution and In Situ Hydrolysis

Snakebite accidents by vipers cause a massive disturbance in hemostasis and tissue damage at the snakebite area. The systemic effects are often prevented by antivenom therapy. However, the local symptoms are not neutralized by antivenoms and are related to the temporary or permanent disability observed in many patients. Although the mechanisms involved in coagulation or necrotic disturbances induced by snake venoms are well known, the disruption of capillary vessels by SVMPs leading to hemorrhage and consequent local tissue damage is not fully understood. In our study, we reveal the mechanisms involved in hemorrhage induced by SVMPs by comparing the action of high and low hemorrhagic toxins isolated from Bothrops venoms, in mouse skin. We show remarkable differences in the tissue distribution and hydrolysis of collagen within the hemorrhagic lesions induced by high and low hemorrhagic metalloproteinases. According to our data, tissue accumulation of hemorrhagic toxins near blood vessel walls allowing the hydrolysis of basement membrane components, preferably collagen IV. These observations unveil new mechanistic insights supporting the local administration of metalloproteinases inhibitors as an alternative to improve snakebite treatment besides antivenom therapy

Venom-related transcripts from Bothrops jararaca tissues provide novel molecular insights into the production and evolution of snake venom.

Attempts to reconstruct the evolutionary history of snake toxins in the context of their co-option to the venom gland rarely account for nonvenom snake genes that are paralogous to toxins, and which therefore represent important connectors to ancestral genes. In order to reevaluate this process, we conducted a comparative transcriptomic survey on body tissues from a venomous snake. A nonredundant set of 33,000 unigenes (assembled transcripts of reference genes) was independently assembled from six organs of the medically important viperid snake Bothrops jararaca, providing a reference list of 82 full-length toxins from the venom gland and specific products from other tissues, such as pancreatic digestive enzymes. Unigenes were then screened for nontoxin transcripts paralogous to toxins revealing 1) low level coexpression of approximately 20% of toxin genes (e.g., bradykinin-potentiating peptide, C-type lectin, snake venom metalloproteinase, snake venom nerve growth factor) in body tissues, 2) the identity of the closest paralogs to toxin genes in eight classes of toxins, 3) the location and level of paralog expression, indicating that, in general, co-expression occurs in a higher number of tissues and at lower levels than observed for toxin genes, and 4) strong evidence of a toxin gene reverting back to selective expression in a body tissue. In addition, our differential gene expression analyses identify specific cellular processes that make the venom gland a highly specialized secretory tissue. Our results demonstrate that the evolution and production of venom in snakes is a complex process that can only be understood in the context of comparative data from other snake tissues, including the identification of genes paralogous to venom toxins

Sympathetic outflow activates the venom gland of the snake Bothrops jararaca by regulating the activation of transcription factors and the synthesis of venom gland proteins

The venom gland of viperid snakes has a central lumen where the venom produced by secretory cells is stored. When the venom is lost from the gland, the secretory cells are activated and new venom is produced. The production of new venom is triggered by the action of noradrenaline on both alpha(1)- and beta-adrenoceptors in the venom gland. In this study, we show that venom removal leads to the activation of transcription factors NF kappa B and AP-1 in the venom gland. In dispersed secretory cells, noradrenaline activated both NF kappa B and AP-1. Activation of NF kappa B and AP-1 depended on phospholipase C and protein kinase A. Activation of NF kappa B also depended on protein kinase C. Isoprenaline activated both NF kappa B and AP-1, and phenylephrine activated NF kappa B and later AP-1. We also show that the protein composition of the venom gland changes during the venom production cycle. Striking changes occurred 4 and 7 days after venom removal in female and male snakes, respectively. Reserpine blocks this change, and the administration of alpha(1)- and beta-adrenoceptor agonists to reserpine-treated snakes largely restores the protein composition of the venom gland. However, the protein composition of the venom from reserpinized snakes treated with alpha(1)- or beta-adrenoceptor agonists appears normal, judging from SDS-PAGE electrophoresis. A sexual dimorphism in activating transcription factors and activating venom gland was observed. Our data suggest that the release of noradrenaline after biting is necessary to activate the venom gland by regulating the activation of transcription factors and consequently regulating the synthesis of proteins in the venom gland for venom production.FAPESP (Fundacao de Amparo a Pesquisa do Estado de Sao Paulo)[02/00422-8]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP (Fundacao de Amparo a Pesquisa do Estado de Sao Paulo)[07/50083-9]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP (Fundacao de Amparo a Pesquisa do Estado de Sao Paulo)[04/11611-1]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Characteristics of neural and humoral systems involved in the regulation of blood pressure in snakes

Cardiovascular function is affected by many mechanisms, including the autonomic system, the kallikrein-kinin system (KKS), the reninangiotensin system (RAS) and the endothelin system. the function of these systems seems to be fairly well preserved throughout the vertebrate scale, but evolution required several adaptations. Snakes are particularly interesting for studies related to the cardiovascular fanction because of their elongated shape, their wide variation in size and length, and because they had to adapt to extremely different habitats and gravitational influences. To keep the normal cardiovascular control the snakes developed anatomical and functional adaptations and interesting structural peculiarities are found in their autonomic, KKS, RAS and endothelin systems. Our laboratory has characterized some biochemical, pharmacological and physiological properties of these systems in South American snakes. This review compares the components and function of these systems in snakes and other vertebrates, and focuses on differences found in snakes, related with receptor or ligand structure and/or function in autonomic system, RAS and KKS, absence of components in KKS and the intriguing identity between a venom and a plasma component in the endothelin system. (c) 2006 Elsevier Inc. All rights reserved.Inst Butantan, Farmacol Lab, BR-05503900 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Farmacol Setor Endocrinol Expt, BR-04044020 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Farmacol Setor Endocrinol Expt, BR-04044020 São Paulo, BrazilWeb of Scienc

The Primary Duct of Bothrops jararaca Glandular Apparatus Secretes Toxins

Submitted by Sandra Infurna ([email protected]) on 2018-09-27T15:39:15Z No. of bitstreams: 1 joseantonio_portesjr_etal_IOC_2018.pdf: 6165008 bytes, checksum: b14c5e58fb2db4ccaae9c736e6652f8f (MD5)Approved for entry into archive by Sandra Infurna ([email protected]) on 2018-09-27T15:47:59Z (GMT) No. of bitstreams: 1 joseantonio_portesjr_etal_IOC_2018.pdf: 6165008 bytes, checksum: b14c5e58fb2db4ccaae9c736e6652f8f (MD5)Made available in DSpace on 2018-09-27T15:47:59Z (GMT). No. of bitstreams: 1 joseantonio_portesjr_etal_IOC_2018.pdf: 6165008 bytes, checksum: b14c5e58fb2db4ccaae9c736e6652f8f (MD5) Previous issue date: 2018Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Toxinologia. Rio de Janeiro, RJ. Brasil / Instituto Nacional de Ciência e Tecnologia em Toxinas. Brasília, DF, Brasil.Instituto Butantan. Laboratório de Farmacologia. São Paulo, SP, Brasil.Instituto Butantan. Laboratório de Imunopatologia. São Paulo, SP, Brasil.Instituto Butantan. Laboratório de Farmacologia. São Paulo, SP, Brasil.Instituto Butantan. Laboratório de Biologia Celular. São Paulo, SP, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Toxinologia. Rio de Janeiro, RJ. Brasil / Instituto Nacional de Ciência e Tecnologia em Toxinas. Brasília, DF, Brasil.Instituto Butantan. Laboratório de Farmacologia. São Paulo, SP, Brasil / Instituto Nacional de Ciência e Tecnologia em Toxinas. Brasília, DF, Brasil.Despite numerous studies concerning morphology and venom production and secretion in the main venom gland (and some data on the accessory gland) of the venom glandular apparatus of Viperidae snakes, the primary duct has been overlooked. We characterized the primary duct of the Bothrops jararaca snake by morphological analysis, immunohistochemistry and proteomics. The duct has a pseudostratified epithelium with secretory columnar cells with vesicles of various electrondensities, as well as mitochondria-rich, dark, basal, and horizontal cells. Morphological analysis, at different periods after venom extraction, showed that the primary duct has a long cycle of synthesis and secretion, as do the main venom and accessory glands; however, the duct has a mixed mode venom storage, both in the lumen and in secretory vesicles. Mouse anti-B. jararaca venom serum strongly stained the primary duct's epithelium. Subsequent proteomic analysis revealed the synthesis of venom toxins-mainly C-type lectin/C-type lectin-like proteins. We propose that the primary duct's toxin synthesis products complement the final venom bolus. Finally, we hypothesize that the primary duct and the accessory gland (components of the venom glandular apparatus) are part of the evolutionary path from a salivary gland towards the main venom gland

Role of disintegrin-like and cysteine-rich domains on the distribution of jararhagin on skin vasculature.

<p>Cryosections were obtained 15 minutes after injection of 5 µg Alexa488-Jar-C in mouse skin. Alexa488-Jar-C accumulated on venules (A) and capillaries walls (B), and showed co-localization with basement membrane staining with type IV collagen (C-red). The sections were examined with a Confocal Microscope LSM 510 Meta (Zeiss).</p