R01AI157205

Host Responses to the Pore-Forming Toxin Listeriolysin O - Summary

Listeria monocytogenes is a facultative intracellular pathogen responsible for the life-threatening disease listeriosis. Although LM produces numerous virulence factors, the secreted pore-forming toxin LLO is indispensable for pathogenesis. LLO is secreted at all stages of the Listeria intracellular life cycle and binds to cholesterol to form transmembrane pores. This virulence factor perforates the membrane of the Listeria-containing endocytic vacuoles to release the bacterium into its replicative niche, the cytosol. It was recently established that LLO also perforates the host cell plasma membrane, which promotes host cell invasion. It remains to elucidate how infected cells maintain viability despite perforation of their plasma membranes and how this low-grade perforation impacts the course of Listeria infection.

The work performed in Aim 1 will establish novel mechanisms that maintain viability of infected cells despite perforation of their plasma membranes by LLO. Preliminary studies, via screening of a large siRNA library, led to the identification of novel families of host proteins that were not previously known to repair the plasma membrane of toxin-perforated cells. The Aim 1 studies will establish the mechanisms of action of these novel proteins. Specifically, they will determine the role plasma membrane depolarization plays in organizing calcium-dependent lysosome exocytosis, leading to the release of cytoprotective cathepsins on the cell surface. Aim 1 will also establish a new role for the septins, a family of cytoskeletal proteins, in plasma membrane repair. These studies will employ high-speed and super-resolution microscopy to analyze the molecular assemblies that orchestrate plasma membrane repair.

The Aim 2 studies will establish the impact of plasma membrane perforation by LLO on Listeria intracellular survival and the innate immune response of antigen-presenting cells. We showed that transient plasma membrane perforation by LLO triggers Ca2+ influx-dependent activation of conventional PKCs on the endosomal network, a signaling event that is critical for Listeria phagosome escape. Aim 2 will identify the PKCs effectors by SILAC-based quantitative proteomic approach and how they contribute to the release of Listeria into the cytosol. Plasma membrane perforation also causes K+ efflux, which is known to activate the NLRP3 inflammasome. Aim 2 will dissect the role of low-grade plasma membrane perforation in the maturation of antigen-presenting cells to enhance T cell immunity, in vitro and in vivo.

This work is expected to broadly impact the development of vaccines and novel therapeutic strategies for a wide range of diseases in which pore-forming toxins are employed by pathogens.

Ohio State University

TO ASSIST PUBLIC AND PRIVATE NONPROFIT INSTITUTIONS AND INDIVIDUALS TO ESTABLISH, EXPAND AND IMPROVE BIOMEDICAL RESEARCH AND RESEARCH TRAINING IN INFECTIOUS DISEASES AND RELATED AREAS, TO CONDUCT DEVELOPMENTAL RESEARCH, TO PRODUCE AND TEST RESEARCH MATERIALS. TO ASSIST PUBLIC, PRIVATE AND COMMERCIAL INSTITUTIONS TO CONDUCT DEVELOPMENTAL RESEARCH, TO PRODUCE AND TEST RESEARCH MATERIALS, TO PROVIDE RESEARCH SERVICES AS REQUIRED BY THE AGENCY FOR PROGRAMS IN INFECTIOUS DISEASES, AND CONTROLLING DISEASE CAUSED BY INFECTIOUS OR PARASITIC AGENTS, ALLERGIC AND IMMUNOLOGIC DISEASES AND RELATED AREAS. PROJECTS RANGE FROM STUDIES OF MICROBIAL PHYSIOLOGY AND ANTIGENIC STRUCTURE TO COLLABORATIVE TRIALS OF EXPERIMENTAL DRUGS AND VACCINES, MECHANISMS OF RESISTANCE TO ANTIBIOTICS AS WELL AS RESEARCH DEALING WITH EPIDEMIOLOGICAL OBSERVATIONS IN HOSPITALIZED PATIENTS OR COMMUNITY POPULATIONS AND PROGRESS IN ALLERGIC AND IMMUNOLOGIC DISEASES. BECAUSE OF THIS DUAL FOCUS, THE PROGRAM ENCOMPASSES BOTH BASIC RESEARCH AND CLINICAL RESEARCH. SMALL BUSINESS INNOVATION RESEARCH (SBIR) PROGRAM EXPANDS AND IMPROVES PRIVATE SECTOR PARTICIPATION IN BIOMEDICAL RESEARCH. THE SBIR PROGRAM INTENDS TO INCREASE AND FACILITATE PRIVATE SECTOR COMMERCIALIZATION OF INNOVATIONS DERIVED FROM FEDERAL RESEARCH AND DEVELOPMENT, TO INCREASE SMALL BUSINESS PARTICIPATION IN FEDERAL RESEARCH AND DEVELOPMENT, AND TO FOSTER AND ENCOURAGE PARTICIPATION OF SOCIALLY AND ECONOMICALLY DISADVANTAGED SMALL BUSINESS CONCERNS AND WOMEN-OWNED SMALL BUSINESS CONCERNS IN TECHNOLOGICAL INNOVATION. THE SMALL BUSINESS TECHNOLOGY TRANSFER (STTR) PROGRAM STIMULATES AND FOSTERS SCIENTIFIC AND TECHNOLOGICAL INNOVATION THROUGH COOPERATIVE RESEARCH AND DEVELOPMENT CARRIED OUT BETWEEN SMALL BUSINESS CONCERNS AND RESEARCH INSTITUTIONS, TO FOSTER TECHNOLOGY TRANSFER BETWEEN SMALL BUSINESS CONCERNS AND RESEARCH INSTITUTIONS, TO INCREASE PRIVATE SECTOR COMMERCIALIZATION OF INNOVATIONS DERIVED FROM FEDERAL RESEARCH AND DEVELOPMENT, AND TO FOSTER AND ENCOURAGE PARTICIPATION OF SOCIALLY AND ECONOMICALLY DISADVANTAGED SMALL BUSINESS CONCERNS AND WOMEN-OWNED SMALL BUSINESS CONCERNS IN TECHNOLOGICAL INNOVATION. RESEARCH CAREER DEVELOPMENT AWARDS SUPPORT THE DEVELOPMENT OF SCIENTISTS DURING THE FORMATIVE STAGES OF THEIR CAREERS. INDIVIDUAL NATIONAL RESEARCH SERVICE AWARDS (NRSAS) ARE MADE DIRECTLY TO APPROVE APPLICANTS FOR RESEARCH TRAINING IN SPECIFIED BIOMEDICAL SHORTAGE AREAS. IN ADDITION, INSTITUTIONAL NATIONAL RESEARCH SERVICE AWARDS ARE MADE TO ENABLE INSTITUTIONS TO SELECT AND MAKE AWARDS TO INDIVIDUALS TO RECEIVE TRAINING UNDER THE AEGIS OF THEIR INSTITUTIONAL PROGRAM.

93.855 - Allergy and Infectious Diseases Research

National Institute of Allergy and Infectious Diseases (NIAID) [HHS - NIH]

Columbus, Ohio 43210 United States

Single Zip Code

Research Project Grant (Parent R01 Clinical Trial Not Allowed) (PA-19-056)

Amendment Since initial award the total obligations have increased 437% from $594,733 to $3,191,205.