Chitin of Paracoccidioides brasiliensis: role in the host-pathogen interaction

• Grant number: 20/16548-9
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: June 01, 2021
• End date: August 31, 2022
• Field of knowledge: Biological Sciences - Immunology - Immunochemistry
• Principal Investigator: Maria Cristina Roque Antunes Barreira
• Grantee: Nayla de Souza Pitangui
• Host Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Associated research grant: 18/21708-5 - Application of immunomoduladors, by carbohydrate recognition, as therapeutic agents: mechanism of action to immunotherapy, AP.TEM

Abstract

The studies about carbohydrate recognition and its biological activities is evaluated by Immunochemistry and Glycobiology Lab, which has the ArtinM lectin, and two lectins from Toxoplasma gondii (TgMIC1 and TgMIC4; TgMICs) and one lectin from Paracoccidioides brasiliensis (Paracoccin, PCN) as major lectins for investigation. The native form of ArtinM, PCN, and TgMICs has been evaluated and the relevance of the biological activity of these lectins instigated us to express them, and the recombinant form of these lectins maintained the biological activities of native forms. ArtinM, obtained from the Artocarpus heterophyllus seeds, has specificity for mannotriose Man± 1-3 [Man± 1-6] Man, and PCN found on P. brasiliensis yeast surface has specificity for N-acetylglucosamine and chitin. TgMICs are found on apical region of T. gondii, and TgMIC1 and TgMIC4 bind, respectively, to ±2-3-sialil lactosamine and ²1-3- or ²1-4-galactosamine. The effect of the ArtinM, PCN, and TgMICs in innate immune cells depend of its interaction with glycoproteins on cell surface, as Toll-like receptors (TLR) 2 and/or TLR4. These innate immune receptors are glycosylated and the recognition by these lectins induce the production of inflammatory mediators, mainly IL-12 and IFN-g, which drive the adaptive immunity to Th1 profile. These mechanisms are related to the immunomodulatory activity promoted by ArtinM, PCN, and TgMICs, and the administration of these lectins favor the protection against intracellular pathogens. Our group also investigated the role of PCN and TgMICs in Biology of the P. brasiliensis and T. gondii, respectively, and in the host-pathogen interaction. Then, our current proposal intends to extent the description of mechanisms involved in the immunomodulatory activity of ArtinM, PCN, and TgMICs, and its application as immunotherapeutic agents. For that, we planned eight proposals that will be useful for understanding the main points as follows: (I) stablish that ArtinM can be a study model to evaluate the immunomodulatory activity through carbohydrate recognition, and also demonstrate the application of ArtinM as immunomodulator agent against systemic fungal infection; (II) stablish that PCN is a virulence factor of P. brasiliensis to explore its function as therapeutic target against Paracoccidioidomycosis; (III) report the cell signaling triggered by TgMICs through interaction with TLR2 and TLR4 on innate immune cells, and also to describe the role of TgMICs during the T. gondii infection. In regard to the PCN lectin, we found that, in addition to binding to chitin, it is also endowed with chitinase activity. As a result, we have investigated the effect ofchitin hydrolysis by PCN on the Biology of P. brasiliensis and the host immune response. Therefore, we have used wild yeast and mutants yeast, silenced or overexpressing NCPs. (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)

PITANGUI, NAYLA DE SOUZA; FERNANDES, FABRICIO FREITAS; GONCALES, RELBER AGUIAR; ROQUE-BARREIRA, MARIA CRISTINA. Virulence Vs. Immunomodulation: Roles of the Paracoccin Chitinase and Carbohydrate-Binding Sites in Paracoccidioides brasiliensis Infection. FRONTIERS IN MOLECULAR BIOSCIENCES, v. 8, AUG 31 2021. (18/21708-5, 17/06251-6, 20/16548-9)