Immunomodulatory actions and epigenetic alterations induced by proteases from Bothrops snake venoms in human immune cells

• Published in: Toxicology in vitro Vol. 61; p. 104586
• Main Authors: Menaldo, Danilo L., Costa, Tássia R., Ribeiro, Diego L., Zambuzi, Fabiana A., Antunes, Lusânia M.G., Castro, Fabíola A., Frantz, Fabiani G., Sampaio, Suely V.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.12.2019; Elsevier Science Ltd
• Subjects: Adult; Animals; Apoptosis; Bothrops; Cell death; Cell Survival; CpG islands; Crotalid Venoms - toxicity; Cytokines - metabolism; Cytotoxicity; Deoxyribonucleic acid; DNA; DNA methylation; Epigenesis, Genetic - drug effects; Epigenetics; Female; Gene expression; Gene Expression Regulation - drug effects; Gene regulation; Genes; Histones; Humans; Immune system; Immunologic Factors - toxicity; Immunomodulation; Immunotherapy; Interleukin 10; Interleukin 2; Interleukin 6; K562 Cells; Killer Cells, Natural; Leukemia; Leukocytes (mononuclear); Leukocytes, Mononuclear - drug effects; Leukocytes, Mononuclear - metabolism; Male; MeCP2 protein; Metalloprotease; Metalloproteases - toxicity; Metalloproteinase; Methyl-CpG binding protein; Natural killer cells; Necrosis; Peripheral blood mononuclear cells; Reptilian Proteins - toxicity; Serine; Serine protease; Serine proteinase; Snake venoms; Snakes; Thrombin; Toxicity; Toxins; Transcription; Tumor cells; Venom toxins; Young Adult; Metalloprotease; Epigenetics; Serine protease; Bothrops; Immunomodulation; Snake venoms
• ISSN: 0887-2333; 1879-3177
• DOI: 10.1016/j.tiv.2019.06.020

The aim of this study was to evaluate the immunomodulatory effects of two toxins from Bothrops snake venoms (the P–I metalloprotease Batroxase and the thrombin-like serine protease Moojase) on human peripheral blood mononuclear cells (PBMC), also investigating changes in the expression of genes related to epigenetic alterations and their immunotherapeutic potential. After 24 h of PBMC stimulation, Batroxase (2 μg/mL) and Moojase (4 μg/mL) increased some cytokine levels (including IL-6 and IL-10), but did not promote cell death processes (apoptosis/necrosis) or alterations in the global DNA methylation levels. Gene expression experiments (RT-qPCR) showed that most of the genes with altered transcript levels encode enzymes that act on histones, such as acetyltransferases (HAT1), deacetylases (HDACs), methyltransferases (DOT1L) or demethylases (KDM5B), indicating that these toxins may alter gene regulation through epigenetic changes mainly related to histones and to methyl-CpG binding proteins (MECP2). Subsequently, the immunotherapeutic potential of these toxins was evaluated using in vitro cytotoxicity assays with NK cells and K562 leukemic cells. Both toxins were able to potentiate the NK cell cytotoxic effects against K562 tumor cells, and the effect of Batroxase was dependent on the concomitant stimulus with IL-2, whereas Moojase increased the NK cytotoxicity independently of IL-2. Thus, Batroxase and Moojase presented interesting immunomodulatory effects that could be explored for the development of new strategies in anticancer immunotherapies. •We evaluated immunomodulatory effects of the toxins Batroxase and Moojase on PBMC.•Both toxins induced the production of cytokines such as IL-6 and IL-10 after 24 h.•The chosen work concentrations did not induce PBMC death by apoptosis or necrosis.•Gene expression indicated regulation through epigenetic changes in histones.•Both toxins potentiated the NK cell cytotoxic effects against K562 tumor cells.