Heat injured stromal cells-derived exosomal EGFR enhances prostatic wound healing after thulium laser resection through EMT and NF-κB signaling

Background: This study investigated shallow heat injury to prostate stromal fibroblasts and epithelial cells and their interaction to regulate the wound healing and the underlying molecular events.

Methods: Prostate stromal fibroblasts and epithelial cells were cultured individually or cocultured and subjected to shallow heat injury for assessments of cell proliferation, migration, apoptosis, cell cycle distribution, and gene expression. The supernatant of heat-injured WPMY-1 cells was collected for exosome extraction and assessments. Furthermore, beagle dogs received thulium laser resection of the prostate (TmLRP) and randomly divided into Gefitinib, GW4869, and control treatment for the histological analysis, tissue re-epithelialization, and epidermal growth factor receptor (EGFR) expression on the prostatic wound surface. Immunofluorescence was to evaluate p63-positive basal progenitor cell trans-differentiation and macrophage polarization and ELISA was to detect cytokine levels in beagles' urine.

Results: Shallow heat injury caused these cells to enter a stressed state and enhanced their crosstalk. The prostate stromal fibroblasts produced and secreted more exosomal-EGFR and other cytokines and chemokines after shallow heat injury, resulting in increased proliferation and migration of prostate epithelial cells during wound healing. The wound healing of the canine prostatic urethra following the TmLRP procedure was slower in the Gefitinib and GW4869 treatment group than in the control group of animals. Immunofluorescence and ELISA showed that reduced EGFR expression interrupted macrophage polarization but increased the inflammatory response.

Conclusions: Shallow heat injury was able to promote the interaction of prostate stromal cells with prostate epithelial cells to enhance wound healing. Stromal-derived exosomal-EGFR plays a crucial role in the balance of the macrophage polarization and prostatic wound healing.