ROS-responsive hydrogel-delivered miR-665 targets STAT3 to alleviate inflammation and promote hair follicle regeneration in alopecia areata.

Abstract

BACKGROUND: Alopecia areata (AA) is an autoimmune disorder characterized by γ-interferon (IFN-γ)-driven CD8 + T-cell infiltration and overactivation of the JAK-STAT pathway; however, safe and long-acting therapies are lacking. MicroRNA (miRNA)-based interventions hold promise as alternatives, but their clinical translation is hindered by poor stability and the absence of targeted delivery systems. METHODS: We identified miR-665 as a key regulator of STAT3 in embryonic mesenchymal stem cell-derived extracellular vesicles via RNA sequencing and functional screening. An injectable, reactive oxygen species (ROS)-responsive hydrogel (PVA-TSPBA) was developed to enable localized and sustained delivery of miR-665. The physicochemical properties, miRNA release kinetics, and biocompatibility of the hydrogels were systematically characterized. Therapeutic efficacy was evaluated in an imiquimod-induced AA mouse model through macroscopic, histological, and immunohistochemical analyses. RESULTS: The PVA-TSPBA hydrogel exhibited excellent injectability, ROS-dependent degradation, and sustained release of miR-665. In vitro, miR-665 overexpression counteracted the IFN-γ-induced suppression of proliferation and migration in keratinocytes and dermal papilla cells by inhibiting STAT3 phosphorylation. In vivo, injection of PVA-TSPBA@miR-665 hydrogel resulted in prolonged miRNA retention, and significantly promoted hair regeneration, restored follicular structure, and reduced T-cell infiltration compared with the control groups. CONCLUSIONS: We developed a biocompatible, ROS-responsive hydrogel platform for the local delivery of miR-665, which effectively attenuated inflammatory signaling and stimulated hair follicle regeneration in AA. This study provides a novel miRNA-biomaterial combination strategy that holds promise for targeted, durable, and safe treatment of AA.