Banca de DEFESA: LUISA COUTINHO COELHO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : LUISA COUTINHO COELHO
DATE: 29/08/2023
TIME: 09:00
LOCAL: Meio virtual
TITLE:

Influence of polysaccharides obtained from the basidiomycete Auricularia auricula on Innate Immune Response

KEY WORDS:

Polysaccharides, prebiotics, immune response, colitis, Cryptococcus neoformans

PAGES: 70
BIG AREA: Ciências Biológicas
AREA: Biologia Geral
SUMMARY:

The use of mushrooms as beneficial health agents dates back thousands of years, especially in Asian culture. The prospect of using polysaccharides, investigated as potential mediators of different immune responses associated with inflammation and infection systems, has been the focus of research in recent years. Recent studies demonstrate that the basidiomycete Auricularia auricula, considered the third most relevant edible mushroom cultivated in the world, is used not only in nutrition, such as functional foods, but also presents value for the pharmaceutical industry for its many bioactive compounds, such as polysaccharides, vitamins, proteins, polyphenols, and minerals. Polysaccharides obtained from this mushroom have been described to present antioxidant, antitumor, anticoagulant, hypoglycaemic, radioprotective, antiviral, and immunomodulatory activities. The modulation of the immune response by polysaccharides is well described in the literature, with the action of cell receptors responsible for binding sugars that lead to cell activation and signaling, triggering an innate and adaptive immune response. The characteristic of the response, though, is associated with the molecular and structural composition of these molecules, which may vary with the monosaccharide composition, branching pattern, molecular weight, solubility, extraction method of the molecule, and the level of purity obtained. One of the polysaccharides characterized as immunostimulatory is the β-glucans, which were valued at approximately $480 million in the global market in 2020. Their market applications include their immunomodulatory potential and their characteristic of functional food. Polysaccharides and oligosaccharides have acquired space within the prebiotic concept, as they are non-digestible fibers that can be beneficial to the host by selectively stimulating the growth and/or activity of microbial populations in the colon. This modulation of the microbiota is associated with a change in the function of the immune response and an improvement in the integrity of the intestinal microbiome. When disturbed, this microbiome can lead to gut dysbiosis that can progress to a chronic tissue immune response. Locally, the change in population leads to the production of metabolites that interfere with tissue homeostasis, leading to damage to the host, called ulcerative colitis. Previous data from the research group indicate that polysaccharides obtained from submerged cultivation of this mushroom induce a protective immune response in pulmonary infection by the fungus Cryptococcus neoformans. In this context, one of the objectives of this work was to evaluate how the administration of exopolysaccharides obtained from the macrofungus Auricularia auricula by gavage in c57BL/6 mice, of wild lineage and Knock-out for the Dectin-1 receptor, would act in an experimental model of colitis, induced by dextran sodium sulfate (DSS). The results indicate that the treatment altered the clinical symptoms of colitis and that the response would be dependent on the Dectin-1 receptor. We also propose an alternative extraction methodology to increase the yield of mycelial polysaccharides and check their biological activity in vitro and in vivo, in an experimental model of Cryptococcus neoformans infection. The molecular characterization results indicate that associated with the increase in yield, we obtained a heteropolymer capable of activating the production of cytokines in vitro, but which did not control the evolution of the fungal infection.

COMMITTEE MEMBERS:
Externa à Instituição - Elaine Rosechrer Carbonero - UFCAT
Presidente - 2223020 - ANAMELIA LORENZETTI BOCCA
Externa ao Programa - 1657325 - LARISSA FERNANDES MATOS - nullExterna ao Programa - 1529483 - MARIA DE FATIMA BORIN - null