Effect of crotoxin on the functionality of in vitro differentiated neutrophils from myeloid progenitors

• Grant number: 13/11302-8
• Support Opportunities: Regular Research Grants
• Start date: December 01, 2013
• End date: November 30, 2015
• Field of knowledge: Biological Sciences - Physiology - General Physiology
• Principal Investigator: Maria Cristina Cirillo
• Grantee: Maria Cristina Cirillo
• Host Institution: Instituto Butantan. Secretaria da Saúde (São Paulo - Estado). São Paulo , SP, Brazil
• Associated researchers: Primavera Borelli Garcia ; Sandra Coccuzzo Sampaio Vessoni

Abstract

Recently we demonstrated that crotoxin (CTX) inhibits, in vitro and in vivo, the process of phagocytosis by neutrophils; this in vivo effect is long lasting, since it can be observed until 14 days after the subcutaneous administration of a single dose of CTX. Furthermore, we demonstrated that this effect is related to the decrease of phosphorylation of tyrosine residues of signaling proteins and related to unsuitable cytoskeleton reorganization. Considering the short life of neutrophils and the rapid elimination of CTX after its administration, it is difficult to explain this long-lasting inhibitory effect. Accordingly, preliminary data showed that CTX inhibits the phagocytic activity of mature neutrophils obtained from bone marrow, 14 days after the subcutaneous administration of CTX. A potential hypothesis to explain this long-lasting effect is the fact that this toxin could alter the functionality of neutrophils during its process of maturation. Thus, the aim of this project is to investigate the effect of CTX on the functional activity of in vitro differentiated neutrophils from their myeloid progenitors. These progenitors will be isolated from the bone marrow of animals pretreated with CTX. After their in vitro differentiation into mature cells, the following parameters will be evaluated: a) transmigration through t.End.1 endothelial cells; b) cell adhesion to extracellular matrix proteins; c) phagocytosis of C3bi-opsonized zimosan particles; d) expression of CR3 receptor (CD11b/CD18); e) expression of signaling molecules, such as, phosphotyrosine, pSyk, pVav1, RhoA, Rac1, Cdc42 and Arp 2/3. This study will contribute to elucidate the mechanisms involved in the long-lasting effect of CTX on inflammatory response. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

LIMA, TATIANE S.; NEVES, CAMILA L.; ZAMBELLI, VANESSA O.; LOPES, FLAVIA S. R.; SAMPAIO, SANDRA C.; CIRILLO, MARIA CRISTINA. Crotoxin, a rattlesnake toxin, down-modulates functions of bone marrow neutrophils and impairs the Syk-GTPase pathway. Toxicon, v. 136, p. 44-55, SEP 15 2017. (13/11302-8)