Evaluation of Leptospira interrogans FecR proteins rLIC10902 and rLIC20185 interaction with human cells and heterologous expression in non-pathogenic Leptospira

• Grant number: 24/14302-3
• Support Opportunities: Scholarships abroad - Research Internship - Master's degree
• Start date: January 24, 2025
• End date: July 23, 2025
• Field of knowledge: Biological Sciences - Microbiology - Applied Microbiology
• Principal Investigator: Ana Lucia Tabet Oller do Nascimento
• Grantee: João Pedro Gaspar Inácio
• Supervisor: Jenifer Coburn
• Host Institution: Instituto Butantan. Secretaria da Saúde (São Paulo - Estado). São Paulo , SP, Brazil
• Institution abroad: Medical College of Wisconsin (MCW), United States
• Associated to the scholarship: 23/08486-1 - "Structural, functional and immunogenic characterization of two proteins of Leptospira interrogans containing FecR domains", BP.MS

Abstract

Pathogenic L. interrogans is the main causative agent of leptospirosis, a worldwide spread spillover that infects approximately 1 million people per year. Leptospiral infection is intimately related to its outer membrane proteins (OMPs), since they are the first structures to interact with a host's molecules. Thus, the study of these proteins is extremely important to understanding the pathogenicity mechanisms of these bacteria. Despite the fact that FecR domain containing proteins are well studied in Escherichia coli and usually related to iron metabolism, its role in L. interrogans is not elucidated. Currently, FecR proteins Lsa19, Lsa33 and LipL45, have already been described as L. interrogans adhesins. Previous data obtained from our group demonstrated that the FecR proteins rLIC10902 and rLIC20185 interacted with extracellular matrix (ECM) molecules and cell receptors in vitro. Therefore, this project aims to validate the biological role of LIC10902 and LIC20185 as putative adhesins of pathogenic L. interrogans. Target proteins, previously cloned in pAE vector, will be produced in E. coli and purified by metal affinity chromatography. Target genes will be cloned in pMaOri with under the control of the LipL32 promoter, for expression in the saprophyte Leptospira biflexa. The interaction of purified proteins and recombinant L. biflexa with human cell lines will be evaluated by binding assays and immunofluorescence microscopy. Also, mice will be infected with recombinant L. biflexa, to evaluate its dissemination pattern and organ colonization. The expertise of Dr. Coburn and her group will be essential to shed light upon these putative adhesins roles in leptospiral infection, thus enhancing the knowledge in this field.