Interleukin‐8/Matrix Metalloproteinase‐9 Axis Impairs Wound Healing in Type 2 Diabetes through Neutrophil Extracellular Traps‐Fibroblast Crosstalk
Dimitrios Tsilingiris, Anastasia‐Maria Natsi, Efstratios Gavriilidis, Christina Antoniadou, Ioanna Eleftheriadou, Ioanna A. Anastasiou, Anastasios Tentolouris, Evangelos Papadimitriou, Evgenios Eftalitsidis, Panagiotis Kolovos, Victoria Tsironidou, Alexandra Giatromanolaki, Μaria Κoffa, Nikolaos Tentolouris, Panagiotis Skendros, Konstantinos Ritis
Abstract
Neutrophils interact with and activate fibroblasts through the release of neutrophil extracellular traps (NETs). We investigated the role of NETs-fibroblast crosstalk in the cutaneous wound healing of type 2 diabetes (T2D). Neutrophils/NETs, serum, and primary human skin fibroblasts (HSFs) were obtained from individuals with T2D and age/sex-matched controls. NET-stimulation studies were performed on neutrophils/HSFs, with and without specific inhibitors, while HSF healing capacity was assessed using a scratch wound healing assay. T2D HSFs display a profibrotic phenotype, showing increased CCN2/CTGF, α-smooth muscle actin, and collagen release, albeit with impaired healing capacity, elevated type I collagen C-terminal telopeptide, and collagen degradation associated with increased (∼3.5-fold) matrix metalloproteinase-9 (MMP-9) in T2D neutrophils/NETs. IL-8 induced the expression of MMP-9 in neutrophils/NETs. Moreover, T2D neutrophils/NETs exhibited increased IL-8 content, which acted in an autocrine/paracrine fashion to further augment its production by neutrophils/HSFs. The findings were validated in normoglycemic individuals during a hyperglycemic clamp with concomitant lipid infusion and further corroborated immunohistochemically in diabetic plantar ulcer biopsies. This novel, vicious circle of NETs/interleukin-8/MMP-9/HSFs was hindered by IL-8 or MMP-9 blockade via specific inhibitors or by dismantling the NET-scaffold with DNase I, suggesting candidate therapeutic targets in wound healing impairment of T2D.