Role of Chromobacterium violaceum ZntA in defense against zinc intoxication imposed by Dictyostelium discoideum

• Grant number: 23/12144-9
• Support Opportunities: Scholarships abroad - Research Internship - Scientific Initiation
• Start date: January 01, 2024
• End date: March 31, 2024
• Field of knowledge: Biological Sciences - Genetics - Molecular Genetics and Genetics of Microorganisms
• Principal Investigator: José Freire da Silva Neto
• Grantee: Carolina Panosso Schuindt
• Supervisor: Thierry Soldati
• Host Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Institution abroad: Université de Genève, Switzerland
• Associated to the scholarship: 22/05740-1 - Role of a P-type ATPase in metal efflux in Chromobacterium violaceum, BP.IC

Abstract

Zinc is a transition metal required as a trace micronutrient for all living organisms. The zinc dual nature - vital for life, toxic in excess - has intriguing implications in host-pathogen interaction. Zinc toxicity can be used by the host as a defense mechanism against pathogens. For instance, immune cells and amoeba can accumulate zinc in the phagosome as part of an antimicrobial response. As a countermeasure to survive within hosts, bacteria express P-type ATPases, which acts as zinc efflux pumps. Previous data of our ongoing project indicate that the P1B2-type ATPase ZntA is determinant for zinc tolerance in the bacterial pathogen Chromobacterium violaceum and the expression of zntA is upregulated under the condition of zinc excess. To complement these in vitro results, we propose in this BEPE project focus on zinc toxicity in vivo during the interaction of C. violaceum with the social amoeba and professional phagocyte Dictyostelium discoideum. Using phagocytic plate assays, fluorescent strains for live-cell imaging, zinc probes, RT-qPCR, and amoeba and bacterial mutant strains, we will investigate: (i) the intracellular fate of C. violaceum within D. discoideum, (ii) the in vivo expression of zntA, (iii) the mechanisms that D. discoideum uses to poison C. violaceum with zinc, and (iv) the role of ZntA as a C. violaceum zinc defense strategy. This study will advance our comprehension on bacterial resistance, virulence, and host-pathogen dynamics, fostering the development of potential zinc-poisoning mediated antimicrobial approaches. (AU)