TNF-α regulates diabetic macrophage function through the histone acetyltransferase MOF
Aaron D. denDekker, … , Steven L. Kunkel, Katherine A. Gallagher
Aaron D. denDekker, … , Steven L. Kunkel, Katherine A. Gallagher
Published February 18, 2020
Citation Information: JCI Insight. 2020;5(5):e132306. https://doi.org/10.1172/jci.insight.132306.
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Research Article Immunology Inflammation

TNF-α regulates diabetic macrophage function through the histone acetyltransferase MOF

Abstract

A critical component of wound healing is the transition from the inflammatory phase to the proliferation phase to initiate healing and remodeling of the wound. Macrophages are critical for the initiation and resolution of the inflammatory phase during wound repair. In diabetes, macrophages display a sustained inflammatory phenotype in late wound healing characterized by elevated production of inflammatory cytokines, such as TNF-α. Previous studies have shown that an altered epigenetic program directs diabetic macrophages toward a proinflammatory phenotype, contributing to a sustained inflammatory phase. Males absent on the first (MOF) is a histone acetyltransferase (HAT) that has been shown be a coactivator of TNF-α signaling and promote NF-κB–mediated gene transcription in prostate cancer cell lines. Based on MOF’s role in TNF-α/NF-κB–mediated gene expression, we hypothesized that MOF influences macrophage-mediated inflammation during wound repair. We used myeloid-specific Mof-knockout (Lyz2Cre Moffl/fl) and diet-induced obese (DIO) mice to determine the function of MOF in diabetic wound healing. MOF-deficient mice exhibited reduced inflammatory cytokine gene expression. Furthermore, we found that wound macrophages from DIO mice had elevated MOF levels and higher levels of acetylated histone H4K16, MOF’s primary substrate of HAT activity, on the promoters of inflammatory genes. We further identified that MOF expression could be stimulated by TNF-α and that treatment with etanercept, an FDA-approved TNF-α inhibitor, reduced MOF levels and improved wound healing in DIO mice. This report is the first to our knowledge to define an important role for MOF in regulating macrophage-mediated inflammation in wound repair and identifies TNF-α inhibition as a potential therapy for the treatment of chronic inflammation in diabetic wounds.

Authors

Aaron D. denDekker, Frank M. Davis, Amrita D. Joshi, Sonya J. Wolf, Ronald Allen, Jay Lipinski, Brenda Nguyen, Joseph Kirma, Dylan Nycz, Jennifer Bermick, Bethany B. Moore, Johann E. Gudjonsson, Steven L. Kunkel, Katherine A. Gallagher

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Figure 3

MOF is elevated in diabetic wound macrophages at late time points.

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MOF is elevated in diabetic wound macrophages at late time points. (A) R...
(A) Representative figures showing Mof complex member expression in day 5 wounds from control and DIO wounds. Three wounds were created using a 6-mm punch on the backs of WT C57BL/6J mice on a normal (13.5% saturated fat) or high-fat (DIO, 60% saturated fat) diet. Wound macrophages (CD11b+CD3–CD19–Ly6G–) were isolated on day 5 after injury. Mof, Msl1, Msl2, and Kansl1 expression was examined by qPCR (n = 3 × 3 mice pooled/replicate; repeated twice). (B) Representative figure showing changes in Mof expression in control and DIO wounds over time. Wound macrophages (CD11b+CD3–CD19–Ly6G–) were isolated on days 1, 3, 5, and 7 after injury and assessed for Mof expression by qPCR (n = 3 × 3 mice pooled/replicate/time point; repeated twice). (C) Representative figures showing H4K16ac deposition on inflammatory cytokine gene promoters in day 5 wounds. DIO and control wound macrophages (CD11b+CD3–CD19–Ly6G–) were isolated on day 5 after wounding. ChIP analysis was performed for H4K16ac at the NF-κB binding site on the promoters of Il1b, Tnf, and Nos2 promoters (n = 3 × 4 mice pooled/replicate, repeated twice). (D) Representative figure showing wound closure in Lyz2Cre Moffl/fl mice on high-fat diet. Two wounds were created using 6-mm punch biopsies on the backs of DIO Lyz2Cre Moffl/fl or DIO Moffl/fl mice. Change in wound area was analyzed daily using ImageJ software (NIH) (n = 6 mice/group; repeated twice). (E) Representative figures showing collagen deposition in day 5 Lyz2Cre Moffl/fl DIO wounds. Wounds from DIO Lyz2Cre Moffl/fl or DIO Moffl/fl mice were harvested on day 5 after injury and processed for histology. Trichrome staining was performed and calculated using ImageJ software (n = 6 mice/group). Scale bar: 2 mm. (F) Representative figure showing MYST1 expression in diabetic and control human PBMCs. Human PBMCs (CD14+) were isolated from T2D or non-T2D control patients. MYST1 expression was measured using qPCR (n = 11 normal, 9 diabetic). (G) Representative figure showing MYST1 expression in diabetic and control human wound tissue. Wounds from T2D or non-T2D control patients were examined for MYST1 expression by qPCR (n = 5). A and C were analyzed using a 2-tailed Student’s t test. B and D were analyzed by multiple t tests (1 per time point). E, F, and G were analyzed using a 1-tailed Student’s t test with Welch’s correction.