Cystic Fibrosis Transmembrane Conductance Regulator: A Possible New Target for Photodynamic Therapy Enhances Wound Healing

Abstract

Objective: Cell migration is an essential process in skin wound healing. Photodynamic therapy (PDT) enhances wound healing by photoactivating a photosensitizer with a specific wavelength of light. Cystic fibrosis transmembrane conductance regulator (CFTR) is an ion channel expressed in multiple layers of keratinocytes. Recent studies showed that the activation of CFTR-related downstream signaling affects skin wound healing. We examined whether indocyanine green (ICG)-mediated PDT-enhanced cell migration is related to CFTR activation. Approach: The spatial and temporal expression levels of CFTR and proteins involved in focal adhesion, including focal adhesion kinase (FAK) and paxillin, were evaluated during cell migration in vitro and in vivo for wound healing. Results: ICG-PDT-conditioned medium collected from cells exposed to 5 J/cm 2 near-infrared light in the presence of 100 μg/mL ICG activated CFTR and enhanced HaCaT cell migration. The expression of phosphorylated FAK Tyr861 and phosphorylated paxillin in focal adhesions was spatially and temporally regulated in parallel by ICG-PDT-conditioned medium. Curcumin, a nonspecific activator of CFTR, further increased PDT-enhanced cell migration, whereas inhibition of CFTR and FAK delayed cell migration. The involvement of CFTR in ICG-PDT-enhanced skin wound healing was confirmed in a mouse back skin wound model. Innovation: CFTR is a potential new therapeutic target in ICG-PDT to enhance wound healing. Conclusion: ICG-PDT-enhanced cell migration may be related to activation of the CFTR and FAK pathway. Conditioned medium collected from ICG-PDT may be useful for treating patients with chronic skin ulcer by regulating CFTR expression in keratinocytes.