Functional characterization of the GF6PA and GNA genes of Trypanosoma cruzi and the relevance of glutamine for parasite biology

• Grant number: 23/11104-3
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: June 01, 2024
• End date: May 31, 2026
• Field of knowledge: Biological Sciences - Parasitology - Protozoology of Parasites
• Principal Investigator: Ariel Mariano Silber
• Grantee: Joice de Melo Agripino
• Host Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 21/12938-0 - Amino acid metabolism in Trypanosoma cruzi: a toolbox to survive in hostile environments, AP.TEM

Abstract

Chagas disease (CD) is a neglected tropical disease considered a public and social health problem, which mainly affects the poor population in countries throughout the Americas. The infectious agent of CD is Trypanosoma cruzi, a parasite with a complex life cycle that involves distinct cellular stages with different morphological, biochemical, and metabolic characteristics. The importance of glycoconjugate biosynthesis in the biology of T. cruzi is well-established. Glutamine (Gln) is an amino acid that participates in the biosynthesis pathway of hexosamines, or amino sugars, which are essential constituents of most glycoconjugates. The first step of this pathway is catalyzed by the enzyme glutamine fructose-6-phosphate aminotransferase (GF6PA, EC 2.6.1.16), which uses Gln as a substrate and nitrogen source to form the products glutamate and glucosamine-6-phosphate (GlcN-6-P). In the second step of the pathway, the enzyme glucosamine-6-phosphate-N-acetyltransferase (GNA, EC 2.3.1.4) transfers an acetyl group to GlcN-6-P, producing GlcNAc-6-P, which is the precursor of UDP-N-acetylglucosamine (UDP-GlcNAc) - an important metabolite for the glycosylation reactions of the parasite's glycoconjugates. In T. cruzi the GF6PA and GNA enzymes have been kinetically characterized by our group (unpublished results), but their functional characterization in the parasite's biology has yet to be carried out. The aim of this study is to conduct a functional analysis of T. cruzi GF6PA and GNA enzymes by producing partial or total knockout strains of the genes responsible for encoding them. The goal is to investigate the effect of these enzymes on the glycome and overall biology of the parasite. The resulting mutant strains will be assessed based on their phenotype, proteome, and glycome. We will also analyze their ability to proliferate, differentiate, and infect mammalian host cells. This study seeks to comprehend the importance of Gln in hexosamine metabolism and to elucidate the roles and functions of the enzymes being investigated. Our goal is to validate them as potential therapeutic targets, paving the way for the development of more effective drugs to combat Chagas disease. (AU)