Role of CD147 in regulating the RSK2/Slug/EMT pathway in diabetic foot ulcer healing.

Objectives: Diabetic foot ulcer (DFU), with a high rate of amputation and mortality, is a serious complication of diabetes. However, the therapeutic effect of diabetic foot is poor. This study aimed to investigate the effect of CD147 on epithelial-mesenchymal transition (EMT) process in DFU and molecular mechanisms.

Methods: Immunohistochemistry was used to reveal the expression of several proteins, such as CD147, E-cadherin, N-cadherin, Slug, and Phospho-RSK2 in DFU, non-diabetic refractory tissues, and wound margin tissues (normal blood glucose). Western blotting was used to analyze the expression of CD147 and Slug in HaCaT cells in the high-glucose environment. HaCaT cells with CD147 or RSK2 knockdown was constructed. Wound healing assay was used to test the migration capability of HaCaT cells with knockdown of CD147. Western blotting was used to detect the protein level of Slug in HaCaT cells with CD147 or RSK2 knockdown to investigate the effects of CD147 or RSK2 on EMT. Immunoprecipitation (IP) assay was used to detect the interaction between CD147 and RSK2.

Results: The expression levels of CD147 and Slug in the epithelial cells of marginal DFU tissues were significantly lower than those in non-diabetic refractory tissues and wound margin tissues (all <0.05). CD147 and Slug expressions were down-regulated in HaCaT cells cultured with high glucose (all <0.05). The migration ability of HaCaT cells with CD147 knockdown was decreased. Knockdown of CD147 or RSK2 significantly inhibited the expression of Slug. The direct interaction between RSK2 and CD147 was found via IP assay.

Conclusions: CD147 could cause DFU re-epithelialization obstacle via affecting RSK2-mediated Slug/EMT process, which might be an underlying mechanism for the slow healing of DFU.