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L-amino acid oxidase from Bothrops atrox snake venom triggers autophagy, apoptosis and necrosis in normal human keratinocytes

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Title: L-amino acid oxidase from Bothrops atrox snake venom triggers autophagy, apoptosis and necrosis in normal human keratinocytes
Authors: Braga, V
Costal-Oliveiraa, F
Stransky, S
Guerra-Duarte, C
Souza, DLND
Vivas-Ruiz, DE
Yarlequé, A
Sanchez, EF
Chávez-Olórtegui, C
Item Type: Journal Article
Abstract: Snake venom L-amino acid oxidases (LAAOs) are flavoproteins, which perform diverse biological activities in the victim such as edema, myotoxicity and cytotoxicity, contributing to the development of clinical symptoms of envenomation. LAAO cytotoxicity has been described, but the temporal cascade of events leading to cell death has not been explored so far. This study evaluates the involvement of LAAO in dermonecrosis in mice and its cytotoxic effects in normal human keratinocytes, the major cell type in the epidermis, a tissue that undergoes extensive necrosis at the snakebite site. Pharmacological inhibition by the antioxidant NAC (N-acetyl cysteine) prevented B. atrox venom-induced necrosis. Consistent with the potential role of oxidative stress in wounding, treatment with purified LAAO decreased keratinocyte viability with an Effective Concentration (EC50) of 5.1 μg/mL. Cytotoxicity caused by LAAO was mediated by H2O2 and treated cells underwent autophagy, followed by apoptosis and necrosis. LAAO induced morphological alterations that precede cell death. Our results show the chronological events leading to cell death and the temporal resolution from autophagy, apoptosis and necrosis as distinct mechanisms triggered by LAAO. Fluorescently-labelled LAAO was efficiently and rapidly internalized by keratinocytes, suggesting that catalysis of intracellular substrates may contribute to LAAO toxicity. A better understanding of LAAO cytotoxicity and its mechanism of action will help to identify potential therapeutic strategies to ameliorate localized snake envenomation symptoms.
Issue Date: 28-Jan-2019
Date of Acceptance: 16-Nov-2018
URI: http://hdl.handle.net/10044/1/66433
DOI: https://doi.org/10.1038/s41598-018-37435-4
ISSN: 2045-2322
Publisher: Nature Publishing Group
Start Page: 1
End Page: 14
Journal / Book Title: Scientific Reports
Volume: 9
Copyright Statement: © The Author(s) 2018. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Cre-ative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not per-mitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
Sponsor/Funder: Medical Research Council (MRC)
CNPq - Science without borders
Wellcome Trust
Funder's Grant Number: MR/M026310/1
Keywords: Science & Technology
Multidisciplinary Sciences
Science & Technology - Other Topics
0601 Biochemistry and Cell Biology
0299 Other Physical Sciences
Publication Status: Published
Article Number: 781
Online Publication Date: 2019-01-28
Appears in Collections:National Heart and Lung Institute