R01AI165797

A Novel Mechanism for NLRP3 Inflammasome Activation in Human Macrophages

Infections and cellular stress can trigger cytoplasmic pattern recognition receptors to assemble an inflammasome complex, which promotes the release of the inflammatory cytokines IL-1β, IL-18, and the induction of pyroptotic cell death. Inflammasome responses are also perpetuated and propagated to bystander cells. Ultimately, this response contributes to pathogen clearance and wound healing. However, excessive inflammasome activation can contribute to or cause debilitating symptoms associated with inflammatory diseases. Particularly, the NLRP3 inflammasome has been directly linked to numerous diseases. It has a unique position by not only sensing infections, but also cellular stress and tissue damage. Even though the NLRP3 inflammasome is of utmost importance for balancing between homeostasis and disease, and is therefore a prime target for novel treatment strategies, the underlying molecular mechanisms, particularly in human macrophages, are still poorly understood. There are numerous human inflammasome components that are absent in mice, and their functional contribution to human health and disease is even less well understood than the more conserved factors. Elucidating unique human responses is the main focus of our lab.

Innate immune receptor oligomerization initiates inflammatory host responses, including inflammasome activation. The research outlined in this proposal is designed to mechanistically unravel a novel NLRP3 inflammasome activation concept in human macrophages. We discovered a novel NLRP3 inflammasome component in human macrophages, which interacts with NLRP3 but is absent from mice. Our preliminary studies revealed that NLRP3 requires this co-sensor for oligomerization as well as for recruiting the inflammasome adaptor, ASC. Furthermore, NLRP3 and its co-sensor are necessary for efficiently nucleating ASC polymerization and caspase-1 activation. Knockout of the co-sensor phenocopies NLRP3 knockout in human macrophages. Significantly, it is absolutely necessary for cytokine release driven by NLRP3 mutations that cause cryopyrin-associated periodic syndrome (CAPS).

We propose two specific aims that investigate the mechanism and function of the co-sensor in NLRP3 inflammasome assembly and activation in macrophages, as well as the molecular events that enable this co-sensor to promote NLRP3 inflammasome activation. We will utilize CRISPR/Cas9 knockout and restored expression of wild type and mutant co-sensor proteins, and a humanized mouse expressing the human co-sensor for studying its function in vivo. We expect that our research will uncover novel molecular mechanisms that not only change our current understanding of control mechanisms that prevent inappropriate NLRP3 inflammasome activation for maintaining homeostasis and human health, but also NLRP3-driven pathologies in inflammatory diseases. The outcomes of our study will move the field forward and will be highly significant for understanding disease pathologies and for the development of novel therapies that benefit patients and positively affect human health.

Cedars-Sinai Medical Center

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]

Los Angeles, California 900481804 United States

Single Zip Code

NIH Research Project Grant (Parent R01 Clinical Trial Not Allowed) (PA-20-185)

Amendment Since initial award the total obligations have increased 400% from $765,715 to $3,828,575.