Ubiquitination Flow Repressors: Enhancing Wound Healing of Infectious Diabetic Ulcers through Stabilization of Polyubiquitinated Hypoxia-Inducible Factor-1α by Theranostic Nitric Oxide Nanogenerators.

Current treatments for diabetic ulcers (DUs) remain unsatisfactory due to the risk of bacterial infection and impaired angiogenesis during the healing process. The increased degradation of polyubiquitinated hypoxia-inducible factor-1α (HIF-1α) compromises wound healing efficacy. Therefore, the maintenance of HIF-1α protein stability might help treat DU. Nitric oxide (NO) is an intrinsic biological messenger that functions as a ubiquitination flow repressor and antibacterial agent; however, its clinical application in DU treatment is hindered by the difficulty in controlling NO release. Here, an intelligent near-infrared (NIR)-triggered NO nanogenerator (SNP@MOF-UCNP@ssPDA-Cy7/IR786s, abbreviated as SNP@UCM) is presented. SNP@UCM represses ubiquitination-mediated proteasomal degradation of HIF-1α by inhibiting its interaction with E3 ubiquitin ligases under NIR irradiation. Increased HIF-1α expression in endothelial cells by SNP@UCM enhances angiogenesis in wound sites, promoting vascular endothelial growth factor (VEGF) secretion and cell proliferation and migration. SNP@UCM also enables early detection of wound infections and ROS-mediated killing of bacteria. The potential clinical utility of SNP@UCM is further demonstrated in infected full-thickness DU model under NIR irradiation. SNP@UCM is the first reported HIF-1α-stabilizing advanced nanomaterial, and further materials engineering might offer a facile, mechanism-based method for clinical DU management.