Project Grant F31HL179993

DISSECTING LUNG ALVEOLAR MACROPHAGE INTERACTIONS WITH T CELLS - SUMMARY BALANCED HOST INFLAMMATION DURING PULMONARY INFECTIONS IS REQUIRED TO PREVENT TISSUE DAMAGE DURING ACUTE LUNG INJURY (ALI). T CELL-DEPENDENT INFLAMMATION IS LINKED TO BINDING THE CO-STIMULATORY MOLECULES CD80 AND CD86 ON LUNG ALVEOLAR MACROPHAGES (AMS) WHICH DRIVES BOTH T CELL ACTIVATION (VIA CD28 LIGATION) AND INHIBITION (VIA CTLA4 LIGATION). WHILE AMS ARE NORMALLY POOR ACTIVATORS OF NAIVE T CELLS, DYSREGULATION OF T CELL MODULATORY MOLECULES, CAN ALTER T CELL-DEPENDENT RESOLUTION AND PULMONARY DAMAGE DURING ALI, INFECTION, OR ASTHMA. HOWEVER, DUE TO EXPERIMENTAL CHALLENGES, WE LACK A MECHANISTIC UNDERSTANDING OF SHARED AND UNIQUE PATHWAYS REGULATING CD80 AND CD86 IN AMS PROHIBITING DEVELOPMENT OF THERAPEUTICS TO TARGET THESE KEY INTERACTIONS. USING A NEW EX VIVO MODEL OF AMS CALLED FETAL LIVER-DERIVED ALVEOLAR-LIKE MACROPHAGES (FLAMS), I AM OVERCOMING THIS EXPERIMENTAL BARRIER TO DEFINE NEW MECHANISMS REGULATING AM FUNCTION. MY PRELIMINARY DATA SHOW THAT RESTING FLAMS AND FLAMS ACTIVATED WITH THE PROINFLAMMATORY CYTOKINE IFNG, DO NOT ROBUSTLY EXPRESS EITHER CD80 OR CD86, LIMITING T CELL INTERACTIONS. HOWEVER, BLOCKING THE METABOLISM-RELATED KINASES GLYCOGEN SYNTHASE KINASE 3A AND 3B (GSK3A/B), THAT MODULATE IFNG RESPONSES, DRIVES HIGH CD80 AND CD86 EXPRESSION IN ACTIVATED FLAMS, RESULTING IN ROBUST T CELL INTERACTIONS. USING TRANSCRIPTOMICS AND TARGETED KNOCKOUTS IN FLAMS, I FOUND THAT THE UPREGULATION OF CD80 AND CD86 ARE UNIQUELY CONTROLLED. CD86, BUT NOT CD80 EXPRESSION, REQUIRED THE PRODUCTION AND SIGNALING OF INTERFERON BETA 1 (IFNB). TO INVESTIGATE CD80 EXPRESSION I FOUND NEW CANDIDATE REGULATORS USING A GENOME-WIDE FORWARD GENETIC SCREEN IN ACTIVATED FLAMS BLOCKED FOR GSK3A/B. TOGETHER MY PRELIMINARY DATA HIGHLIGHT OUR CONTINUED LACK OF UNDERSTANDING OF CD80 AND CD86 REGULATION AND DEFINE NEW LINKS BETWEEN AMS, METABOLISM, AND T CELL EFFECTOR FUNCTION, AND ALI PROGRESSION. MY OVERALL HYPOTHESIS IS THAT THE DISTINCT REGULATION OF CD80 OR CD86 ON AMS WILL PREVENT DYSREGULATED PULMONARY T CELL RESPONSES TO PROTECT AGAINST SEVERE ALI. THE GOAL OF THIS PROPOSAL IS TO USE GENETIC AND CHEMICAL APPROACHES IN FLAMS TO DISSECT SHARED AND UNIQUE MECHANISMS REGULATING CD80 AND CD86 EXPRESSION AND DETERMINE THEIR CONTRIBUTION TO T CELL FUNCTION IN THE LUNGS. IN AIM 1, I WILL DETERMINE THE MECHANISMS UNIQUELY REGULATING CD80 AND CD86 IN AMS. IN AIM 2, I WILL EXAMINE HOW DYSREGULATION OF CD80 AND CD86 IN AMS ALTERS T CELL FUNCTION AND ALI SEVERITY. TOGETHER, THESE AIMS WILL DEFINE THE REGULATORY MECHANISMS OF CD80 AND CD86 AND DISSECT THEIR CONTRIBUTION TO T CELL FUNCTION IN THE LUNGS. A BETTER UNDERSTANDING OF HOW APC-DEPENDENT LIGANDS CD80 AND CD86 ARE REGULATED, WILL IDENTIFY NEW STRATEGIES TO MODULATE T CELL FUNCTION AND PROTECT FROM ACUTE LUNG INJURY. THE EXPERIMENTS IN THIS PROPOSAL WILL BE PERFORMED IN THE SUPPORTIVE TRAINING ENVIRONMENT AT MICHIGAN STATE UNIVERSITY AND DEPARTMENT OF MICROBIOLOGY, GENETICS, AND IMMUNOLOGY. MY FULL TRAINING PLAN WILL HELP ME DEVELOP THE RESEARCH AND COMMUNICATION SKILLS NECESSARY TO BECOME A SUCCESSFUL INDEPENDENT RESEARCHER.