Inhibition of CCL28/CCR10-mediated eNOS Downregulation Improves Skin Wound Healing in the Obesity-induced Mouse Model of Type 2 Diabetes

Abstract

<p>Chronic, non-healing skin wounds such as diabetic foot ulcers (DFUs) are common in patients with type 2 diabetes. Here, we investigated the role of chemokine CCL28 and its receptor CCR10 in downregulation of endothelial nitric oxide synthase (eNOS) in association with delayed skin wound healing in the <em>db/db</em> mouse model of type 2 diabetes. We observed reduced eNOS expression and elevated CCL28/CCR10 levels in dorsal skin of <em>db/db</em> mice and subdermal leg biopsies from human subjects with type 2 diabetes. Further interrogation revealed that overexpression of CCR10 reduced eNOS expression, NO bioavailability, and tube formation of human dermal microvascular endothelial cells (HDMVECs) <em>in vitro</em> which was recapitulated in mouse dorsal skin. In addition, incubation of HDMVECs with CCL28 led to internalization of the CCR10/eNOS complex and co-localization with lysosome-associated membrane protein-1. Finally, topical application of myristoylated CCR10 binding domain 7 amino acid (Myr-CBD7) peptide prevented CCR10-eNOS interaction and subsequent eNOS downregulation, enhanced eNOS/NO levels, eNOS/VEGF-R2+ microvessel density, and blood perfusion, reduced inflammatory cytokine levels, and importantly, decreased wound healing time in <em>db/db</em> mice. Thus, endothelial cell CCR10 activation in genetically obese mice with type 2 diabetes promotes eNOS depletion and endothelial dysfunction, and targeted disruption of CCR10/eNOS interaction improves wound healing </p>