Epigenetic Regulation of Diabetic Wound Inflammation

Background and Innovation: Non-healing wounds in patients with Type 2 Diabetes (T2D) are a major cause of morbidity and mortality in the Veteran population and are increasing at an alarming rate. Failure of wound healing in T2D patients represents the most common cause of amputation in US Veterans with a 5-year mortality rate of nearly 50%. Thus, a critical need exists for understanding the wound healing defects in T2D in order to develop targeted therapies. We will utilize both genetic (db/db) and dietary (diet-induced obese) murine models of T2D as well as human wound tissue and blood samples collected from T2D patients to explore mechanisms of impaired wound healing under diabetic conditions. We present data using human single cell RNA sequencing and murine diabetic wound models, that the histone acetyltransferase, MOF, is increased in diabetic wound macrophages (Mφs) resulting in a persistent inflammatory Mφ phenotype with increased production of inflammatory genes and decreased production of IFNꞵ. Further, using human cells and our experimental murine models of wound repair and diabetes, we have identified that TNFα is increased in diabetic wound tissue and induces Mof transcription in wound Mφs resulting in an increase in MOF in human wound MΦs from T2D patients; however, the mechanisms by which MOF specifically regulates Mφ function in normal or diabetic wounds is unclear. Our new preliminary data identify that, in addition to direct regulation of inflammatory gene promoters, MOF acetylates interferon regulatory factor 3 (IRF3) in Mφs resulting in repression of downstream genes, including IFNβ. This is important as we and others have shown that IFNβ expression is reduced in T2D wounds and, via induction of another CME, SETDB2, is critical for the downregulation of inflammatory genes in Mφs during the transition from a pro- to an anti-inflammatory phenotype. These results have led to our hypothesis that TNFα-receptor mediated signaling in Mφs increases Mof expression via an NFκB mechanism and MOF then downregulates the IRF3/IFNβ/SETDB2 axis to increase inflammation in diabetic wound MΦs. This effectively prevents diabetic wounds from moving to a reparative state and ultimately healing. We further postulate that Mφ function may be restored via Mφ-targeted inhibition of the MOF-mediated epigenetic modifications resulting in the resolution of inflammation and tissue repair. This hypothesis will be investigated via the following specific aims: Aim1) Define MOF regulation of the IRF3/IFNβ/SETDB2 axis in normal and diabetic wound Mφs. Aim 2) Examine keratinocyte TNFα production and TNFα-receptor 1 (TNFR1) mediated regulation of MOF in wound Mφs using human and murine diabetic wound tissues. Aim 3) Examine the therapeutic efficacy and timing of Mφ-targeted MOF and TNFR1 inhibition on diabetic wound repair. Significance and Impact to Veterans Health Care: Non-healing diabetic wounds are a major cause of amputation in Veterans and a major research priority for VHA/ORD is improving wound repair in diabetes and other pathologies that affect Veterans. Path to translation: Our data will pave the way for the development of promising therapeutic agents aimed at cell-specific targeting of epigenetic pathways that mediate diabetic wound Mφ inflammation and promote diabetic wound repair and decrease amputations in Veterans. Project Number: 1I01BX006545-01A1 | Fiscal Year: 2026 | NIH Institute/Center: Veterans Affairs (VA) | Principal Investigator: Katherine Gallagher | Institution: VETERANS HEALTH ADMINISTRATION, ANN ARBOR, MI | Activity Code: I01 | Study Section: Special Emphasis Panel[ZRD1 SURG-P (01)] View on NIH RePORTER: https://reporter.nih.gov/project-details/11052678