Evaluation of the effects of ethanol and metabolites on the effector and modulating response of macrophages to the dimorphic fungus Paracoccidioides brasiliensis

Author(s)

Lívia Furquim de Castro

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Ciências Médicas
• Defense date: 2019-07-25

Examining board members

Ronei Luciano Mamoni; Angela Maria Victoriano de Campos Soares; Luciane Alarcão Dias Melício; Danilo Ciccone Miguel; Plinio Trabasso

• Advisor: Ronei Luciano Mamoni

Abstract

Background: Paracoccidioidomycosis (PCM), a systemic granulomatous inflammatory disease caused by fungi of the genus Paracoccidioides, affects mainly immunocompetent individuals, being the major cause of systemic mycosis of Latin America. PCM is characterized by several immunological and clinical manifestations and can be classified in two main clinical forms: the chronic form (CF), more localized, and the acute/subacute form (AF), more severe and disseminated. The AF is characterized by the commitment of the cellular immune response, with a predominant Th2/Th9 response. While the CF is characterized by developing a heterogeneous immune response, with predominant participation of Th17/Th22 cells, cytokines characteristics of Th1 response and variable amounts of IL-10 and IL-4. Some studies have shown that ethanol consumption could interfere with the effector's functions of immune cells and, consequently, increase the susceptibility to infections. In PCM, the alcoholism is considered a risk factor for the evolution of the disease, mainly in the CF; however, to the best our knowledge, the effect of ethanol in the alterations of the effector mechanisms of the immune response has not been fully determined, particularly in human PCM. Objective: This study aims to investigate the effects of ethanol and compounds derivate from ethanol metabolism in effector and modulating functions of macrophages in response to the fungus P. brasiliensis, and to determine their influence on the development of the adaptive immune response. Methods: Purified peripheral blood monocytes were differentiated into macrophages and treated with ethanol (25Mm, 150mM), ß-hydroxybutyrate and sodium acetate, stimulated with P. brasiliensis yeast cells and evaluated for their phenotypic characteristics, functional activity and induction of differentiation of T cells. Results: We found that the ethanol treatment diminished the expression of MHC-I, MHC-II, CD80 and CD86, modulating the expression of dectin-1, as well as phosphorylation of Syk protein. We also observed that, after the treatment, macrophages presented an increased phagocytic activity and higher expression of CD206. However, the ethanol treatment reduced the production of ROS, the fungicidal activity, cleavage of caspase-1 and release of IL-1ß. We also observed that the presence of ethanol diminished the IL-6 production and increase de IL-10 release. Finally, our data showed that the presence of ethanol reduced the differentiation of Th1 and Th17 cells and increased the frequency of Th2 cells. Conclusions: Altogether our data indicated that the ethanol exposure and its metabolites (sodium acetate and ?-hydroxubutyrate) can suppress of the effector of macrophages and modulates of the immune response against P. brasiliensis, possibly leading to the polarization of M2 macrophages. The ethanol presence interferes with the expression of costimulatory and antigen-presentation molecules and with fungal recognition, through the reduction of dentin-1 expression and Syk phosphorylation. The ethanol possibly blockage of the NLRP3 inflammasome activation and, consequently, reduce the IL-1? production. Altogether these alterations affect the activation and development of the acquired immune response, decreasing the frequency of IL-17, IL-22, and IFN-gamma producing T lymphocytes and increasing the frequency of IL-4 producing cells. Therefore, the ethanol exposure can present profound effects in the immune response to the P. brasiliensis infection, impairing the ability to macrophages to exert their effector functions to eliminate the fungus and to the establishment of the effective acquired immune response related to resistance to infection (AU)

• FAPESP's process: 15/18788-9 - Evaluation of ethanol effects on the effector response of macrophages to the dimorphic fungus P. brasiliensis .
• Grantee: Lívia Furquim de Castro
• Support Opportunities: Scholarships in Brazil - Doctorate