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Influence of Insulin-like growth factor (IGF) -I on the parasitism of mice peritoneal macrophages by Leishmania (L.) infantum

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Author(s):
Ariane Farias Leal
Total Authors: 1
Document type: Master's Dissertation
Press: São Paulo.
Institution: Universidade de São Paulo (USP). Instituto de Medicina Tropical de São Paulo (IMT)
Defense date:
Examining board members:
Hiro Goto; Claudia Maria de Castro Gomes; Nancy Starobinas
Advisor: Hiro Goto
Abstract

In leishmaniasis, it is known that in both resistance and susceptibility to infection, the cellular immune response is considered the most important. However, in the initial phase, nonspecific factors are being considered as fundamental in determining the course of the disease, such as insulin-like growth factor I (IGF-I). Studies carried out in the research group of Profa. Dr. Hiro Goto showed that extrinsic IGF-I favors parasite proliferation and infection progression, with decrease in nitric oxide production and activation of arginase of macrophages and parasite. It is known that macrophages produced IGF-I (intrinsic IGF-I), thus, in the present study we have investigated the effect of the intrinsic factor in the parasitism on macrophages of BALB/c mice infected with L. (L.) infantum by silencing the expression of messenger RNA (IGF-I mRNA) in the cell by the interference RNA technique (siRNA). We started evaluating the expression of IGF-I mRNA and its receptor (IGF-IR). A 1.4-fold decrease in IGF-I mRNA expression was observed in 24 hours and a 1.5-fold increase in 48 hours as compared to the control group. An increase in mRNA expression of the IGF-IR was also observed in 24 as well as in 48 hours in the infected groups as compared to the control group. With IGF-I silencing by siRNA, there was a decrease in IGF-I mRNA expression in the macrophage around 71% in 24 hours and 51% in 48 hours. In the absence or decrease of IGF-I in the macrophage, a decrease in the parasitism in the infection with promastigotes was observed, and the parasitism recovered with the replacement of extrinsic IGF-I in the system, confirming the importance of IGF-I in the proliferation of the parasite. These results reinforce the importance of IGF-I in L. infantum infection, suggesting that IGF-I is directly related to the parasitism. (AU)

FAPESP's process: 14/08340-8 - Effect of Insulin-like Growth Factor-I (IGF-I) on parasitism of mouse peritoneal macrophages by Leishmania (L.) infantum
Grantee:Ariane Farias Leal
Support Opportunities: Scholarships in Brazil - Master