CGAS-STING Mediated Inflammation In Diabetic Wound Macrophages Is Regulated By Histone Demethylase JMJD3

Abstract

Abstract Recent work has shown that the cGAS-STING inflammatory pathway is elevated in conditions that are marked by chronic inflammation, such as obesity and diabetes. Using single cell RNA (scRNA) sequencing from human wounds, we show that the Sting gene is increased in diabetic wound macrophages. Histone demethylase JMJD3 specifically demethylates lysine 27 on histone 3 (H3K27me3) - a repressive mark for gene transcription. Using diabetic mice, we note on ChIP analysis, a decrease in the H3K27me3 repressive mark at the STING promoter in diabetic wound macrophages relative to littermate controls, with subsequently enhanced STING protein levels by western blot. Additionally, scRNA from wound macrophages obtained from a novel murine strain deficient in Jmjd3 in myeloid-cell lineages (Jmjd3f/fLyz2Cre+), revealed significantly decreased Sting gene levels. Further, ChIP analysis of H3K27me3 levels at the STING promoter from Jmjd3f/fLyz2Cre+ wound macrophages reveal increased H3K27me3 levels compared to littermate controls, with a concomitant decrease in STING protein as determined by western blot. Mechanistically, we use mRNA, protein and ChIP studies to reveal that in diabetic wound macrophages, IL6 is responsible for increased JMJD3 leading to increased JAK1,3/STAT3 activity and increased STING production. Wound healing curves from diabetic mice locally treated with macrophage-specific nanoparticles against JMJD3 showed significantly improved healing, and decreased STING protein production in these wounds. Taken together, this data highlights a unique epigenetic regulator of STING production in diabetic wound macrophages and provides a viable cell-specific, nanotherapeutic approach to non-healing diabetic wounds. Supported by NIH (F32DK126471), Vascular and Endovascular Surgical Society Resident Research Award