Interleukin-8 Overexpressing Collagen Microgel-Based Cellular Microtissue Accelerates the Healing of Diabetic Foot Ulcers

Abstract

Diabetic foot ulcers (DFUs) represent a major clinical challenge due to impaired healing and limited therapeutic options. Although stem cell therapy offers regenerative potential, its efficacy is restricted by poor survival and engraftment at the injury site. To address this, collagen microgels (CMGs) are developed to assemble with cells to form CMG-based cellular microtissues (CCMs) with enhanced porosity, mass transfer, and viability. However, the diabetic microenvironment impairs healing by suppressing angiogenesis, keratinocyte migration, and fibroblast proliferation. Transcriptomic profiling identifies interleukin-8 (IL-8) as a key factor with multifaceted roles in promoting angiogenesis, migration, and proliferation. Compared with conventional aggregates, CCMs enhance adhesion, prevent anoikis, improve survival, and upregulate IL-8 via FGFR-integrin-ERK signaling. Functional studies using shRNA knockdown and adenoviral overexpression validate the therapeutic role of IL-8. In vitro co-culture with keratinocytes, fibroblasts, and endothelial cells shows that CCMs promoted migration, proliferation, and angiogenesis-effects diminished by IL-8 knockdown and amplified by overexpression. In a rat DFU model, CCMs accelerate wound closure by enhancing granulation tissue formation, collagen deposition, and expression of proliferative and angiogenic markers, all modulated by IL-8. These findings establish CCMs as an effective therapeutic platform for DFUs and highlight IL-8 overexpression as a strategy to further potentiate regeneration.