Monocyte/macrophage androgen receptor suppresses cutaneous wound healing in mice by enhancing local TNF-α expression
Jiann-Jyh Lai, Kuo-Pao Lai, Kuang-Hsiang Chuang, Philip Chang, I-Chen Yu, Wen-Jye Lin, Chawnshang Chang
Jiann-Jyh Lai, Kuo-Pao Lai, Kuang-Hsiang Chuang, Philip Chang, I-Chen Yu, Wen-Jye Lin, Chawnshang Chang
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Research Article Dermatology

Monocyte/macrophage androgen receptor suppresses cutaneous wound healing in mice by enhancing local TNF-α expression

Abstract

Cutaneous wounds heal more slowly in elderly males than in elderly females, suggesting a role for sex hormones in the healing process. Indeed, androgen/androgen receptor (AR) signaling has been shown to inhibit cutaneous wound healing. AR is expressed in several cell types in healing skin, including keratinocytes, dermal fibroblasts, and infiltrating macrophages, but the exact role of androgen/AR signaling in these different cell types remains unclear. To address this question, we generated and studied cutaneous wound healing in cell-specific AR knockout (ARKO) mice. General and myeloid-specific ARKO mice exhibited accelerated wound healing compared with WT mice, whereas keratinocyte- and fibroblast-specific ARKO mice did not. Importantly, the rate of wound healing in the general ARKO mice was dependent on AR and not serum androgen levels. Interestingly, although dispensable for wound closure, keratinocyte AR promoted re-epithelialization, while fibroblast AR suppressed it. Further analysis indicated that AR suppressed wound healing by enhancing the inflammatory response through a localized increase in TNF-α expression. Furthermore, AR enhanced local TNF-α expression via multiple mechanisms, including increasing the inflammatory monocyte population, enhancing monocyte chemotaxis by upregulating CCR2 expression, and enhancing TNF-α expression in macrophages. Finally, targeting AR by topical application of a compound (ASC-J9) that degrades AR protein resulted in accelerated healing, suggesting a potential new therapeutic approach that may lead to better treatment of wound healing.

Authors

Jiann-Jyh Lai, Kuo-Pao Lai, Kuang-Hsiang Chuang, Philip Chang, I-Chen Yu, Wen-Jye Lin, Chawnshang Chang

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Figure 5

AR enhances local TNF-α expression through multiple mechanisms.

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AR enhances local TNF-α expression through multiple mechanisms. (A) Immu...
(A) Immunohistochemistry to identify infiltrating myeloid cells (CD11b+) and macrophages (F4/80+) in day 3 wounds. White arrows indicate foci of positive-staining cells (brown). Scale bars: 100 μm. (B) The positive-staining cells were counted in the wound areas. n = 6–7. (C) Flow cytometry to identify the monocytes (CD11b+F4/80+), inflammatory monocytes (CD11b+F4/80+Gr1+), and resident monocytes (CD11b+F4/80+Gr1–) in PBMCs. n = 4–9. (D) mRNA isolated from BMMacs was subjected to quantitative RT-PCR to detect expression of chemokine receptors. For each chemokine receptor, the expression level of WT BMMacs treated with LPS was set as 1. (E) NIH3T3 cells were transiently transfected with reporter containing the promoter region (–1,258 to +27) of murine CCR2 together with pWPI-mAR or empty vector. After treating cells with or without DHT, luciferase activities were measured. (F and G) Transwell chemotaxis assay was used to compare chemotaxis of day 3 BMMacs in response to MCP-1. (F) Images of cells that had migrated across the membrane. Original magnification, ×100. (G) Cell numbers were counted. n = 9. (H) Day 6 BMMacs were treated with LPS as indicated. TNF-α production was measured by ELISA. (I) Reporters composed of TNF-α promoter containing 5′-UTR (pGL3-TNF, –1,203 to +122) or without 5′-UTR (pGL3-TNF, –1,203 to +2) were cotransfected into NIH3T3 cells with pWPI-mAR or pWPI. After treating with DHT, luciferase activities were measured. Data in I are mean ± SD. *P < 0.001 versus all other groups.