IL-17A-mediated JMJD3 regulation of Cxcl1 gene expression in diabetic keratinocytes increases neutrophil recruitment and impairs wound repair.

Abstract

Diabetic keratinocytes display an overexpression of chemokines that contribute to prolonged inflammation and non-healing. Using sequencing, we identified that Th17 cells and an IL-17A signature predominate in human diabetic wound tissue compared to non-diabetic controls. The effects of increased IL-17A in diabetic skin on keratinocyte function is unknown. We subjected isolated murine keratinocytes to a 5hr rIL-17A stimulation and performed bulk RNA-seq. We observed increased neutrophil chemoattract genes Cxcl1, Cxcl3, Cxcl5 compared to their controls. We analyzed epigenetic enzymes known to increase gene expression and identified that JMJD3, an activating demethylase, was increased both in human and murine diabetic keratinocytes. IL-17A stimulation increased Jmjd3 expression in murine keratinocytes, and keratinocytes from mice with a keratinocyte-specific IL-17RA deficiency were unable to increase Jmjd3 with rIL-17A. Treatment with a JMJD3-specific inhibitor decreased chemokine genes in IL-17A-stimulated keratinocytes. Keratinocytes from mice with a keratinocyte-specific JMJD3-deficiency displayed decreased chemokines compared to their littermate controls with rIL-17A, suggesting that JMJD3 is relevant to IL-17A-mediated regulation of chemokines. We then analyzed immune cells recruited to the wounds of normal and diabetic mice via flow cytometry and found that Ly6G+ neutrophils were significantly increased in diabetic mice on day 5, a timepoint at which IL-17A is elevated.