IL-17A-mediated JMJD3 regulation of integrin alpha 3 gene expression alters migration of diabetic keratinocytes and impairs wound repair

Abstract Keratinocytes are key structural cells in cell migration during wound repair. Keratinocyte migration is dysfunctional in diabetes and results in non-healing, however, the reason for this is unclear. Using bulk and single cell sequencing, we identified that Th17 CD4+ T-cells predominate as does an IL-17A signature in human diabetic wound tissue compared to non-diabetic controls. The effects of increased IL-17A in diabetic skin on keratinocyte function is unknown. To examine this, we subjected isolated keratinocytes to scratch injury and a 24hr rIL-17A (20ng) stimulation. We observed a significant decrease in migration rate in IL-17A stimulated keratinocytes compared to their controls. Next, we examined migration related genes in keratinocytes from mice fed with a normal (ND) or a high fat (HFD) diet. Integrin alpha 3 subunit, Itga3, (a protein known to delay keratinocyte migration during wound re-epithelialization) was higher in diabetic (HFD) keratinocytes compared to ND controls at baseline and with rIL-17A. We analyzed epigenetic enzymes known to increase gene expression and identified that JMJD3, a histone demethylase that relaxes chromatin, was increased both in diabetic keratinocytes from our human scRNA-seq and in murine diabetic keratinocytes with rIL17A. Further, treatment with a JMJD3-specific inhibitor (GSK-J4) decreased Itga3 in diabetic keratinocytes, suggesting that JMJD3 may be relevant to IL-17A-mediated regulation of integrin alpha 3 and other keratinocyte migration genes. Continued investigation into upstream IL-17A signaling in normal and diabetic keratinocytes that alters downstream migration is crucial for our understanding of impaired keratinocyte functions associated with diabetic wound repair. NIH T32 AI 007413, Research Training in Experimental Immunology Rackham Pre-Candidate Graduate Student Research Grant, University of Michigan