KGF-2 Alleviates Dry Eye Disease by Regulating the HMGB1/TLR4 Pathway.

PURPOSE: This study aimed to investigate the protective effects of keratinocyte growth factor-2 (KGF-2) in dry eye disease (DED) and elucidate its mechanism of action through the regulation of the HMGB1/TLR4 pathway. METHODS: Two in vitro models were established by stimulating hyperosmolar human corneal epithelial cells (HCECs) and RAW 264.7 cells with lipopolysaccharide. A DED mice model was established using scopolamine and an intelligently controlled environmental system. After KGF-2 treatment, the symptoms of the DED mice were assessed. The changes in inflammatory factors were measured using Western blotting and quantitative reverse-transcription polymerase chain reaction (RT-qPCR). RNA sequencing (RNA-seq) was used to identify the key factors involved in KGF-2 treatment, followed by validation through in vivo and in vitro knockdown of the relevant factors. RESULTS: KGF-2 treatment significantly relieved DED in the mice model through increased tear secretion, and improved fluorescein staining scores. In addition, the levels of inflammatory factors were effectively lowered in both in vitro and in vivo models. Bulk RNA-seq analysis suggested that KGF-2 exerts its effects by regulating the HMGB1/TLR4 pathway. Furthermore, KGF-2 treatment inhibited the upregulation and nuclear translocation of HMGB1 in the DED model, thereby suppressing the levels of inflammatory factors associated with the HMGB1/TLR4 pathway. Knockdown of HMGB1 in HCECs and glycyrrhizin treatment in DED mice exhibited therapeutic effects similar to those of KGF-2. CONCLUSIONS: KGF-2 demonstrated protective effects in both in vivo and in vitro DED models by modulating the HMGB1/TLR4 pathway. These findings suggest its potential as a therapeutic agent for DED, warranting further clinical investigation in this regard.