Project Grant F31AI202526

REGULATION OF INFLAMMATION AND TISSUE REMODELING BY MACROPHAGE MIGRATION INHIBITORY FACTOR FOLLOWING MYCOBACTERIUM TUBERCULOSIS INFECTION - PROJECT SUMMARY TUBERCULOSIS (TB) IS CAUSED BY MYCOBACTERIUM TUBERCULOSIS (MTB). IN 2024, 10.7 MILLION PEOPLE FELL ILL WITH TB. OF THOSE WHO COMPLETE ANTIBIOTIC TREATMENT AND ACHIEVE MICROBIOLOGIC CURE, MANY WILL BE LEFT WITH INCREASED DISABILITY, RISK OF TB RELAPSE, AND RISK OF DEATH. IT IS ESTIMATED THAT 50% OF TB SURVIVORS WILL DEVELOP POST-TB LUNG DISEASE (PTLD). PTLD IS CHARACTERIZED BY THE REORGANIZATION OF THE PULMONARY TISSUE FOLLOWING TB DISEASE RESULTING IN FIBROSIS, CAVITATION, BRONCHIECTASIS, AND OBSTRUCTIVE LUNG DISEASE. CURRENTLY, THE MECHANISMS OF PTLD ARE NOT UNDERSTOOD; HOWEVER, RESEARCH ON NON-INFECTIOUS PULMONARY DISEASES WITH INFLAMMATION-BASED TISSUE REMODELING SUGGESTS THAT MACROPHAGE MIGRATION INHIBITORY FACTOR (MIF) COULD PLAY A PATHOGENIC ROLE. MIF IS A PLEIOTROPIC CYTOKINE THAT IS UPREGULATED IN RESPONSE TO INFLAMMATORY STIMULI SUCH AS MTB INFECTION. MIF IS SECRETED FROM A VARIETY OF CELLS AND CAN SIGNAL THROUGH THE CELL SURFACE RECEPTOR CD74 AND CO-RECEPTORS CXCR4 OR CD44. OUR PROPOSAL WILL INVESTIGATE IF MIF SIGNALING IS INVOLVED IN CELLULAR CHANGES AND EXTRACELLULAR MATRIX REMODELING FOLLOWING MTB INFECTION WHICH COULD LEAD TO THE DEVELOPMENT OF PTLD PATHOLOGIES. IN AIM 1, WE WILL INVESTIGATE THE INVOLVEMENT OF MIF IN DRIVING FIBROBLAST ACTIVATION AND COLLAGEN PRODUCTION FOLLOWING MTB INFECTION USING IN VITRO MODEL SYSTEMS. TO UNDERSTAND HOW MIF MEDIATES IMMUNE AND FIBROBLAST CELL CROSSTALK, WE WILL COCULTURE MTB-INFECTED IMMUNE CELLS (ENRICHED OR DEPLETED OF T CELLS) AND FIBROBLASTS TOGETHER TO OBSERVE PHENOTYPIC CHANGES IN THE PRESENCE OR ABSENCE OF MIF. TO MORE ACCURATELY MODEL THE IN VIVO PULMONARY ENVIRONMENT, WE WILL USE AN EX VIVO LUNG MODEL THAT WILL PROVIDE INSIGHT INTO THE ROLE MIF PLAYS ON EPITHELIAL AND FIBROBLAST CELLS FOLLOWING MTB-INFECTION. THESE CULTURE SYSTEMS WILL ALLOW US TO MECHANISTICALLY PROBE THE MIF SIGNALING PATHWAY TO DETERMINE ITS ROLE IN THE ACTIVATION OF FIBROBLASTS AND DEPOSITION OF EXTRACELLULAR MATRIX. IN AIM 2, WE WILL THEN DETERMINE THE ASSOCIATION BETWEEN MIF AND MTB-INDUCED LUNG INJURY IN A PROSPECTIVE PTLD HUMAN COHORT AND TB-ASSOCIATED FIBROSIS MOUSE MODEL. FIRST, TO INVESTIGATE HOW SERUM CONCENTRATIONS OF MIF CORRELATE WITH PULMONARY DYSFUNCTION FOLLOWING TB TREATMENT, WE WILL MEASURE THE CONCENTRATION OF MIF IN THE SERUM OF INDIVIDUALS WITH POST-TB LUNG COMPLICATIONS AT THE END OF TB TREATMENT AND AT FOLLOW UP 18 MONTHS LATER. THEN TO OBSERVE THE SPATIAL EXPRESSION OF MIF WITHIN THE LUNG AND HOW IT CORRELATES WITH THE DEVELOPMENT OF TB- ASSOCIATED FIBROSIS, WE WILL PERFORM CONFOCAL MICROSCOPY AND UNBASED SPATIAL ANALYSIS ON LUNGS OF MICE EXHIBITING MTB-INDUCED PULMONARY FIBROSIS. OUR PROPOSAL WILL PROVIDE VALUABLE INSIGHT INTO THE MECHANISMS OF PTLD PATHOGENESIS BOTH IN THE DEVELOPMENT OF TISSUE DAMAGE AND FIBROTIC FOCI. THIS RESEARCH WILL NOT ONLY ELUCIDATE MIF'S ROLE IN THE LUNG AND DURING MTB-INFECTION BUT WILL ALSO DETERMINE IF MIF INHIBITORS SHOULD BE DEVELOPED AS HOST-DIRECTED THERAPY FOR TB.