Man Xiao-Yong, Yang Xiao-Hong, Cai Sui-Qing, Yao Yong-Gang, Zheng Min
Department of Dermatology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310009, P.R. China.
Mol Med. 2006 Jul-Aug;12(7-8):127-36. doi: 10.2119/2006-00024.Man.
Vascular endothelial growth factor (VEGF) plays an important role in normal and pathological angiogenesis. VEGF receptors (VEGFRs, including VEGFR-1, VEGFR-2, and VEGFR-3) and neuropilins (NRPs, including NRP-1 and NRP-2) are high-affinity receptors for VEGF and are typically considered to be specific for endothelial cells. Here we showed expression of VEGFRs and NRPs on cultured epidermal keratinocytes at both mRNA and protein levels. We further localized these receptors by immunofluorescence (IF) staining in the epidermis of surgical skin specimens. We found positive staining for VEGFRs and NRPs in all layers of the epidermis except for the stratum corneum. VEGFR-1 and VEGFR-2 are primarily expressed on the cytoplasmic membrane of basal cells and the adjacent spinosum keratinocytes. All layers of the epidermis except for the horny cell layer demonstrated a uniform pattern of VEGFR-3, NRP-1, and NRP-2. Sections staining for NRP-1 and NRP-2 also showed diffuse intense fluorescence and were localized to the cell membrane and cytoplasm of keratinocytes. In another panel of experiments, keratinocytes were treated with different concentrations of VEGF, with or without VEGFR-2 neutralizing antibody in culture. VEGF enhanced the proliferation and migration of keratinocytes, and these effects were partially inhibited by pretreatment with VEGFR-2 neutralizing antibody. Adhesion of keratinocytes to type IV collagen-coated culture plates was decreased by VEGF treatment, but this reduction could be completely reversed by pretreatment with VEGFR-2 neutralizing antibody. Taken together, our results suggest that the expression of VEGFRs and NRPs on keratinocytes may constitute important regulators for its activity and may possibly be responsible for the autocrine signaling in the epidermis.
血管内皮生长因子（VEGF）在正常和病理性血管生成中起重要作用。VEGF受体（VEGFRs，包括VEGFR - 1、VEGFR - 2和VEGFR - 3）和神经纤毛蛋白（NRPs，包括NRP - 1和NRP - 2）是VEGF的高亲和力受体，通常被认为是内皮细胞特异性的。在此我们展示了VEGFRs和NRPs在培养的表皮角质形成细胞中mRNA和蛋白水平的表达。我们通过免疫荧光（IF）染色在手术皮肤标本的表皮中进一步定位这些受体。我们发现在除角质层外的表皮所有层中VEGFRs和NRPs呈阳性染色。VEGFR - 1和VEGFR - 2主要表达于基底细胞和相邻棘层角质形成细胞的细胞质膜上。除角质细胞层外的表皮所有层均显示VEGFR - 3、NRP - 1和NRP - 2的均匀分布模式。NRP - 1和NRP - 2染色切片也显示弥漫性强荧光，并定位于角质形成细胞的细胞膜和细胞质。在另一组实验中，角质形成细胞在培养中用不同浓度的VEGF处理，有或无VEGFR - 2中和抗体。VEGF增强了角质形成细胞的增殖和迁移，并且这些作用被VEGFR - 2中和抗体预处理部分抑制。VEGF处理降低了角质形成细胞与IV型胶原包被培养板的黏附，但这种降低可被VEGFR - 2中和抗体预处理完全逆转。综上所述，我们的结果表明角质形成细胞上VEGFRs和NRPs的表达可能构成其活性的重要调节因子，并且可能负责表皮中的自分泌信号传导。
