Student Korea University of Science & Technology, Republic of Korea
Abstract: Diabetic foot ulcers (DFUs) affect around 25% of diabetic patients, posing a major clinical challenge due to impaired wound healing. While stem cell therapy has demonstrated potential in promoting tissue regeneration through paracrine signaling, its efficacy is limited by poor cell survival after transplantation. To address this, we developed collagen microgels (CMGs), micro-sized collagen gels that self-assemble with human adipose-derived stem cells (hASCs) to form CMG-cell microtissue (CCM). Nevertheless, the hyperglycemic microenvironment in diabetic patients disrupts angiogenesis and reduces the proliferation and migration of fibroblasts and keratinocytes, ultimately impairing wound healing. Interleukin-8 (IL-8), a well-characterized paracrine factor, possesses angiogenic, migratory, and proliferative properties, all of which are compromised in diabetic wounds. Therefore, to enhance the therapeutic efficacy of stem cell therapy, we identified IL-8 as a key target and overexpressed it in hASCs via adenoviral transduction. In this study, we optimized CMG:cell ratio (4:1) based on rheological properties, porosity, biocompatibility, and gene expression. Compared to conventional cell aggregates, CCMs exhibited increased IL-8 expression, attributed to enhanced integrin activation via CMG-cell interactions, which was accompanied by fibroblast growth factor receptor activation. In vitro transwell co-culture of CCMs with keratinocytes, fibroblasts, and endothelial cells demonstrated superior angiogenic, migratory, and proliferative effects compared to conventional cell aggregates. Furthermore, IL-8 knockdown impaired these properties, whereas IL-8 overexpression enhanced them, implying crucial role of IL-8 in wound healing. In a streptozotocin-induced diabetic rat model, IL-8-overexpressing CCMs significantly accelerated wound healing, as evidenced by increased granulation tissue formation and collagen deposition, whereas IL-8 knockdown impeded healing. Collectively, these findings highlight the advantages of the CCM platform over conventional cell spheroids in improving stem cell therapy outcomes. Moreover, IL-8 overexpression further enhances therapeutic effectiveness, suggesting IL-8 as a potential target for DFU treatment.
Funding Source: This work was funded by Korean Fund for Regenerative Medicine, the Ministry of Science and ICT and the Ministry of Health & Welfare of Korea.
