Project Grant F30HL189419

EGFR PATHWAY MODULATION TO ATTENUATE BASAL CELL REPAIR AND ENABLE TARGETED PRECONDITIONING FOR AIRWAY CELL THERAPY - ABSTRACT THE CONDUCTING AIRWAY EPITHELIUM FORMS A PROTECTIVE BARRIER THAT FILTERS INHALED PATHOGENS AND POLLUTANTS AND REPAIRS ITSELF THROUGH ACTIVATION OF BASAL CELLS (BCS), THE AIRWAY STEM CELL POPULATION. WHEN REPAIR CAPACITY IS EXCEEDED, CHRONIC INJURY DRIVES AIRWAY DISEASES SUCH AS CYSTIC FIBROSIS (CF) AND PRIMARY CILIARY DYSKINESIA (PCD) TO END-STAGE LUNG DISEASE. FOR SOME OF THESE PATIENTS LUNG TRANSPLANTATION REMAINS THE ONLY CURATIVE OPTION. CELL- BASED THERAPY FOR GENETIC AIRWAY DISEASE IS A NASCENT FIELD WITH THE THEORETICAL POTENTIAL TO CURE THE LUNG DISEASE IN PERSONS WITH CF OR PCD. OUR GROUP RECENTLY ESTABLISHED THE FEASIBILITY OF THIS APPROACH IN A MURINE MODEL. WE DEMONSTRATED THAT TRANSPLANTED BCS, THE MAJOR STEM CELL OF THE AIRWAYS, CAN EFFICIENTLY REGENERATE AIRWAY EPITHELIUM IN MICE. THIS APPROACH REQUIRES A SIGNIFICANT INJURY ("PRECONDITIONING") TO THE HOST EPITHELIUM, BUT CLINICAL TRANSLATION WILL REQUIRE SAFER AND MORE PRECISE METHODS OF OPENING THE NICHE TO DONOR CELLS. WE REASON THAT MOLECULAR TARGETING OF HOST AIRWAY REPAIR PATHWAYS IS A TRACTABLE APPROACH TO PRECISE AND MILDER PRECONDITIONING FOR CELL-BASED THERAPY. MY PRELIMINARY DATA SHOW THAT PHARMACOLOGIC EGFR INHIBITION WITH ERLOTINIB SLOWS BC-MEDIATED REPAIR IN VITRO AFTER INJURY, CREATING A TEMPORARY WINDOW THAT IMPROVES DONOR BC ADHERENCE AND GROWTH. BUILDING ON THESE FINDINGS, THE GOAL OF THIS PROPOSAL IS TO DEFINE THE MOLECULAR PROGRAMS THAT GOVERN BC-MEDIATED AIRWAY REPAIR AND DETERMINE HOW EGFR INHIBITION CAN PRECONDITION THE AIRWAY FOR DONOR CELL THERAPY. IN AIM 1, WE WILL DELINEATE THE MOLECULAR NETWORKS THAT REGULATE BC-DRIVEN REPAIR, FOCUSING ON EGFR-DEPENDENT AND COMPENSATORY SIGNALING PATHWAYS, USING SINGLE-CELL AND SPATIAL TRANSCRIPTOMICS (ST) TO MAP THE TRANSCRIPTIONAL LANDSCAPE OF AIRWAY REPAIR WITH AND WITHOUT EGFR INHIBITION IN A MURINE TRACHEAL INJURY MODEL. IN AIM 2, WE WILL TEST WHETHER TRANSIENT EGFR INHIBITION CAN REDUCE THE DEGREE OF EPITHELIAL INJURY REQUIRED FOR EFFECTIVE DONOR ENGRAFTMENT BY COMBINING ERLOTINIB PRECONDITIONING WITH MILD DETERGENT (POLIDOCANOL) INJURY AND ASSESSING REPAIR KINETICS, PROLIFERATION, AND DONOR INTEGRATION THROUGH HISTOLOGIC ANALYSES, AS WELL AS QUANTIFYING ENGRAFTMENT EFFICIENCY USING IVIS IMAGING AND FLOW CYTOMETRY. TOGETHER, THESE STUDIES WILL ADVANCE UNDERSTANDING OF AIRWAY REGENERATION, IDENTIFY MOLECULAR MECHANISMS BY WHICH EGFR INHIBITION ALTERS THE REPAIR NICHE, AND ESTABLISH A TARGETED, CLINICALLY TRANSLATABLE STRATEGY FOR PRECONDITIONING THE AIRWAY EPITHELIUM.