Uchiyama Akihiko, Yamada Kazuya, Ogino Sachiko, Yokoyama Yoko, Takeuchi Yuko, Udey Mark C, Ishikawa Osamu, Motegi Sei-ichiro
Department of Dermatology, Gunma University Graduate School of Medicine, Maebashi, Japan.
Dermatology Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland.
Am J Pathol. 2014 Jul;184(7):1981-90. doi: 10.1016/j.ajpath.2014.03.017. Epub 2014 May 15.
Our research group recently demonstrated that pericytes are major sources of the secreted glycoprotein and integrin ligand lactadherin (MFG-E8) in B16 melanoma tumors, and that MFG-E8 promotes angiogenesis via enhanced PDGF-PDGFRβ signaling mediated by integrin-growth factor receptor crosstalk. However, sources of MFG-E8 and its possible roles in skin physiology are not well characterized. The objective of this study was to characterize the involvement of MFG-E8 in skin wound healing. In the dermis of normal murine and human skin, accumulations of MFG-E8 were found around CD31(+) blood vessels, and MFG-E8 colocalized with PDGFRβ(+), αSMA(+), and NG2(+) pericytes. MFG-E8 protein and mRNA levels were elevated in the dermis during full-thickness wound healing in mice. MFG-E8 was diffusely present in granulation tissue and was localized around blood vessels. Wound healing was delayed in MFG-E8 knockout mice, compared with the wild type, and myofibroblast and vessel numbers in wound areas were significantly reduced in knockout mice. Inhibition of MFG-E8 production with siRNA attenuated the formation of capillary-like structures in vitro. Expression of MFG-E8 in fibrous human granulation tissue with scant blood vessels was less than that in granulation tissue with many blood vessels. These findings suggest that MFG-E8 promotes cutaneous wound healing by enhancing angiogenesis.
我们的研究小组最近证明,周细胞是B16黑色素瘤肿瘤中分泌性糖蛋白和整合素配体乳粘连蛋白(MFG-E8)的主要来源,并且MFG-E8通过整合素-生长因子受体串扰介导的增强的血小板衍生生长因子(PDGF)-血小板衍生生长因子受体β(PDGFRβ)信号促进血管生成。然而,MFG-E8的来源及其在皮肤生理学中的可能作用尚未得到充分表征。本研究的目的是表征MFG-E8在皮肤伤口愈合中的作用。在正常小鼠和人类皮肤的真皮中,发现MFG-E8在CD31(+)血管周围积聚,并且MFG-E8与PDGFRβ(+)、α平滑肌肌动蛋白(αSMA)(+)和神经胶质抗原2(NG2)(+)周细胞共定位。在小鼠全层伤口愈合过程中,真皮中的MFG-E8蛋白和mRNA水平升高。MFG-E8弥漫性存在于肉芽组织中,并定位于血管周围。与野生型相比,MFG-E8基因敲除小鼠的伤口愈合延迟,并且基因敲除小鼠伤口区域的肌成纤维细胞和血管数量显著减少。用小干扰RNA(siRNA)抑制MFG-E8的产生可减弱体外毛细血管样结构的形成。在血管稀少的纤维性人类肉芽组织中,MFG-E8的表达低于血管丰富的肉芽组织。这些发现表明,MFG-E8通过增强血管生成促进皮肤伤口愈合。