Signaling of Prostaglandin E Receptors, EP3 and EP4 Facilitates Wound Healing and Lymphangiogenesis with Enhanced Recruitment of M2 Macrophages in Mice.

Kanako Hosono,Tadashi Kawakami,Masataka Majima,Shuh Narumiya,Risa Isonaka,Tohru Fukai

doi:10.1371/journal.pone.0162532

Kanako Hosono, Tadashi Kawakami + Show 4 more

Open Access

https://doi.org/10.1371/journal.pone.0162532

Copy DOI

Journal: PloS one	Publication Date: Oct 6, 2016
Citations: 32	License type: CC BY 4.0

Affiliation: Kitasato University, Kyoto University

Abstract

Lymphangiogenesis plays an important role in homeostasis, metabolism, and immunity, and also occurs during wound-healing. Here, we examined the roles of prostaglandin E2 (PGE2) receptor (EP) signaling in enhancement of lymphangiogenesis in wound healing processes. The hole-punch was made in the ears of male C57BL/6 mice using a metal ear punch. Healing process and lymphangiogenesis together with macrophage recruitment were analyzed in EP knockout mice. Lymphangiogenesis was up-regulated in the granulation tissues at the margins of punched-hole wounds in mouse ears, and this increase was accompanied by increased expression levels of COX-2 and microsomal prostaglandin E synthase-1. Administration of celecoxib, a COX-2 inhibitor, suppressed lymphangiogenesis in the granulation tissues and reduced the induction of the pro-lymphangiogenic factors, vascular endothelial growth factor (VEGF) -C and VEGF-D. Topical applications of selective EP receptor agonists enhanced the expressions of lymphatic vessel endothelial hyaluronan receptor-1 and VEGF receptor-3. The wound-healing processes and recruitment of CD11b-positive macrophages, which produced VEGF-C and VEGF-D, were suppressed under COX-2 inhibition. Mice lacking either EP3 or EP4 exhibited reduced wound-healing, lymphangiogenesis and recruitment of M2 macrophages, compared with wild type mice. Proliferation of cultured human lymphatic endothelial cells was not detected under PGE2 stimulation. Lymphangiogenesis and recruitment of M2 macrophages that produced VEGF-C/D were suppressed in mice treated with a COX-2 inhibitor or lacking either EP3 or EP4 during wound healing. COX-2 and EP3/EP4 signaling may be novel targets to control lymphangiogenesis in vivo.

Highlights

Lymphangiogenesis, the formation of new lymphatic vessels from pre-existing ones, plays important physiological roles in the homeostasis of interstitial fluids, metabolism, and immunity
To estimate lymphangiogenesis in the inflammatory granulation tissues formed during wound healing, the ears of mice were subjected to hole-punch injuries
A time course analysis revealed that lymphatic vessel endothelial hyaluronan receptor-1 (LYVE-1) mRNA expression in the granulation tissues of the wound margins was biphasically increased on day1–2 and 5–7 (Fig 1C)

Summary

Introduction

Lymphangiogenesis, the formation of new lymphatic vessels from pre-existing ones, plays important physiological roles in the homeostasis of interstitial fluids, metabolism, and immunity. Vascular endothelial growth factor (VEGF)-C and VEGF-D, which have similar domain structures, are primary pro-lymphangiogenic factors and have been reported to induce lymphangiogenesis via VEGF receptor-3 (VEGFR-3) signaling in various inflammatory models[10, 13,14,15,16]. It was reported previously that pro-inflammatory cytokines, including interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), can upregulate VEGF-C and VEGFR-3 expression[17, 18], and that macrophages activated by these cytokines play a role in pathological lymphangiogenesis by reciprocal interactions with the VEGF-C/ D-VEGFR-3 system[4, 19, 20]. Administration of lymphatic growth factors or their antagonists may enable targeting of lymphatic vessels in human disease[14]

Methods

Results

Conclusion