Anticoagulant Activity of Naja nigricollis Venom Is Mediated by Phospholipase A2 Toxins and Inhibited by Varespladib

Taline D. Kazandjian, Arif Arrahman, Kristina B.M. Still, Govert W. Somsen, Freek J. Vonk, Nicholas R. Casewell, Mark C. Wilkinson, Jeroen Kool

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

Bites from elapid snakes typically result in neurotoxic symptoms in snakebite victims. Neurotoxins are, therefore, often the focus of research relating to understanding the pathogenesis of elapid bites. However, recent evidence suggests that some elapid snake venoms contain anticoagulant toxins which may help neurotoxic components spread more rapidly. This study examines the effects of venom from the West African black-necked spitting cobra (Naja nigricollis) on blood coagulation and identifies potential coagulopathic toxins. An integrated RPLC-MS methodology, coupled with nanofractionation, was first used to separate venom components, followed by MS, proteomics and coagulopathic bioassays. Coagulation assays were performed on both crude and nanofractionated N. nigricollis venom toxins as well as PLA2s and 3FTx purified from the venom. Assays were then repeated with the addition of either the phospholipase A2 inhibitor varespladib or the snake venom metalloproteinase inhibitor marimastat to assess whether either toxin inhibitor is capable of neutralizing coagulopathic venom activity. Subsequent proteomic analysis was performed on nanofractionated bioactive venom toxins using tryptic digestion followed by nanoLC-MS/MS measurements, which were then identified using Swiss-Prot and species-specific database searches. Varespladib, but not marimastat, was found to significantly reduce the anticoagulant activity of N. nigricollis venom and MS and proteomics analyses confirmed that the anticoagulant venom components mostly consisted of PLA2 proteins. We, therefore, conclude that PLA2s are the most likely candidates responsible for anticoagulant effects stimulated by N. nigricollis venom.

Original languageEnglish
Article number302
Pages (from-to)1-20
Number of pages20
JournalToxins
Volume13
Issue number5
Early online date23 Apr 2021
DOIs
Publication statusPublished - May 2021

Bibliographical note

Copyright:
This record is sourced from MEDLINE/PubMed, a database of the U.S. National Library of Medicine

Funding

Funding: This research was funded by an Indonesian Endowment Fund for Education (LPDP) Ph.D. research studentship [S-5622/LPDP.4/2020] to A.A. and a UK Medical Research Council grant [MR/S00016X/1] and a Wellcome Trust and Royal Society Sir Henry Dale Fellowship [200517/Z/16/Z] to N.R.C.

FundersFunder number
Indonesian Endowment Fund for EducationS-5622/LPDP.4/2020
Royal Society Sir Henry Dale Fellowship200517/Z/16/Z
Wellcome Trust
Medical Research CouncilMR/S00016X/1

    Keywords

    • coagulopathy
    • marimastat
    • mass spectrometry
    • Naja nigricollis
    • nanofractionation
    • snakebite
    • varespladib

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