Unraveling the structure-function relationship between edible microalgae non-starch polysaccharides and their effects on immune cells

• Grant number: 22/08480-0
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: December 15, 2022
• End date: June 29, 2023
• Field of knowledge: Health Sciences - Pharmacy - Food Science
• Principal Investigator: João Roberto Oliveira do Nascimento
• Grantee: Leandro Almeida Domiciano de Andrade
• Supervisor: Victor Costa Castro Alves
• Host Institution: Faculdade de Ciências Farmacêuticas (FCF). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: Örebro University, Sweden
• Associated to the scholarship: 21/13969-6 - Evaluation of the immunomodulatory potential of polysaccharides isolated from microalgae, BP.DR

Abstract

Dietary fibers, made up of non-starch polysaccharides (NSP) resistant to hydrolysis by human digestive enzymes, are recognized for their positive health effects. Some of them can interact with defense cells and modulate the immune system. Dietary NSPs are predominantly of plant origin but can also be present in edible fungi and algae. Microalgae are unicellular eukaryotes rich in lipids, proteins, amino acids, carotenoids, and carbohydrates, and despite the technological potential for use in food formulation, little is known about the immunomodulatory activity of their NSPs. Considering that the modulatory effect can occur as a result of the similarity of the NSP with molecular structures associated with pathogens, some NSPs can act as modifiers of the biological response of defense cells, probably through the interaction with Toll-like receptors (TLR)2 and TLR4 expressed in macrophages. Thus, to characterize microalgae NSPs with immunomodulatory activity, the molecular fragments of microalgae NSPs responsible for provoking responses in cells similar to human macrophages will be identified to establish the relationship between their structure and modulatory activity. Microalgae polysaccharide fragments will be obtained by non-enzymatic hydrolysis and selected based on their effects on human monocyte cell line THP-1. The effects of hydrolysates will be evaluated through non-target metabolomics analysis (cell fingerprint) and possible induced changes in cytokine production. Polysaccharide fragments that demonstrate biological activity will then be characterized using different high-resolution mass spectrometry techniques. Based on the results of these assays, it is expected to establish a link between the structural and chemical characteristics of the molecular fragments of microalgae NSPs and their effects on the immune system cells. (AU)