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The role of NLRP3 in the control of autophagy during T. cruzi infection

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Author(s):
Kely Catarine Matteucci
Total Authors: 1
Document type: Doctoral Thesis
Press: São Paulo.
Institution: Universidade de São Paulo (USP). Instituto de Ciências Biomédicas (ICB/SDI)
Defense date:
Examining board members:
Karina Ramalho Bortoluci; Claudio Romero Farias Marinho; Renato Arruda Mortara; Gustavo José da Silva Pereira; Alessandra Pontillo
Advisor: Karina Ramalho Bortoluci
Abstract

Autophagy and inflammasome activation are two cell-autonomous and cross-regulated processes involved in host resistance against infections. Our group previously described that NLRP3 inflammasome is required for the control of T. cruzi, causative agent of Chagas disease. However, the involvement of autophagy in this process was largely unknown. Here, we demonstrated that T. cruzi is able to induce an increase in LC3II expression, formation of autophagosome and autolysosomes in peritoneal macrophages (PMs) from C57BL/6 mice. Moreover, the pharmacological modulation of autophagic machinery influenced the trypanocidal ability of PMs, pointing out autophagy as an effector mechanism to control T. cruzi infection. In this sense, NLRP3 seems to be involved in the modulation of the autophagic process. In the absence of NLRP3, the pharmacological modulation of autophagy did not interfere in the control of T. cruzi by PMs. Furthermore, autophagic flux is blocked in these cells in response to infection, but not in response to rapamycin and starvation. In fact, whereas T. cruzi induces the formation of large autolysosomes (LC3&#43 and Lysotracker&#43)-containing amastigotes in WT macrophages, only small and single positive vesicles are found in the absence of NLRP3. Interesting, NLRP3 appears to act independently of caspase-1/11 on the regulation of autophagy. On the other hand, the PCR-array analysis of autophagic genes demonstrated that NLRP3-/- PMs have higher basal expression of genes related to the formation and maturation of autophagosomes and autolysosomes in comparison to WT cells. In contrast, T. cruzi inhibited the expression of these genes in the absence of NLRP3, unlike the induction observed in WT PMs. Together, these data show that NLRP3 induces functional autophagy in response to T. cruzi being its presence required to overcome the escape of the parasite by preventing its inhibition of autophagic genes. (AU)

FAPESP's process: 15/09568-5 - Role of autophagy in the control of infection by Trypanosoma cruzi and the influence of the innate immunity receptors in this process
Grantee:Kely Catarine Matteucci
Support type: Scholarships in Brazil - Doctorate (Direct)