Histone Acetylation Landscape and the Role of HAT1 in Regulating Corneal Epithelial Wound Healing

Histone acetyltransferase 1 (HAT1) plays critical roles in chromatin remodeling and gene expression; however, its specific role during corneal epithelial wound healing remains unknown. This study aimed to elucidate the function and underlying mechanisms of HAT1-mediated histone acetylation in corneal epithelial wound healing.

Murine corneal epithelial wound healing models were established using an Alger brush. Corneal epithelial-specific Hat1 conditional knockout mice were generated using the Cre-loxP system. Histone acetylation profile, including H4K5 acetylation (H4K5Ac), was assessed by Western blotting. HAT1 expression in human corneal epithelial cells was experimentally altered via small interfering RNA-mediated knockdown or vector-based overexpression. Cell-cycle progression, proliferation, and migration were evaluated by flow cytometry, EdU assays, and scratch wound assays, respectively. RNA sequencing identified candidate HAT1-regulated genes, and their expression and promoter acetylation were validated by quantitative RT-PCR, Western blotting, and chromatin immunoprecipitation assays. Therapeutic effects of HDAC inhibitor TSA and HAT activator SPV106 were evaluated in vivo.

HAT1 expression and global H4K5Ac levels significantly increased during wound healing. In vivo, Hat1 deletion significantly delayed corneal healing and reduced epithelial proliferation at the wound margins. In vitro, HAT1 knockdown in human corneal epithelial cells induced G1-phase arrest and inhibited proliferation and migration, whereas its overexpression reversed these effects. Cyclin D1 and cyclin-dependent kinase 6 were identified as key downstream effectors associated with HAT1-dependent promoter H4K5Ac. Importantly, pharmacological enhancement of histone acetylation via TSA or SPV106 significantly accelerated corneal healing in mice.

Our data indicate that HAT1 promotes corneal epithelial wound healing, in part by upregulating cyclin D1/cyclin-dependent kinase 6, and highlight the potential of enhancing histone acetylation to improve corneal epithelial wound healing.