Yoshito Terai

Roles of two VEGF receptors, Flt-1 and KDR, in the signal transduction of VEGF effects in human vascular endothelial cells.

Vascular endothelial growth factor (VEGF) is a principal regulator of vasculogenesis and angiogenesis. VEGF expresses its effects by binding to two VEGF receptors, Flt-1 and KDR. However, properties of Flt-1 and KDR in the signal transduction of VEGF-mediated effects in endothelial cells (ECs) were not entirely clarified. We investigated this issue by using two newly developed blocking monoclonal antibodies (mAbs) against Flt-1 and KDR. VEGF elicits DNA synthesis and cell migration of human umbilical vein endothelial cells (HUVECs). The pattern of inhibition of these effects by two mAbs indicates that DNA synthesis is preferentially mediated by KDR. In contrast, the regulation of cell migration by VEGF appears to be more complicated. Flt-1 regulates cell migration through modulating actin reorganization, which is essential for cell motility. A distinct signal is generated by KDR, which influences cell migration by regulating cell adhesion via the assembly of vinculin in focal adhesion plaque and tyrosine-phosphorylation of focal adhesion kinase (FAK) and paxillin.

Vascular smooth muscle cell growth-promoting factor/F-spondin inhibits angiogenesis via the blockade of integrin αvβ3 on vascular endothelial cells

Vascular smooth muscle cell growth‐promoting factor (VSGP) was originally isolated from bovine ovarian follicular fluid as a stimulator of vascular smooth muscle cell proliferation. Homology searches indicate that bovine and human VSGPs are orthologs of rat F‐spondin. Here, we examined whether recombinant human VSGP/F‐spondin affected the biological activities of endothelial cells. VSGP/F‐spondin did not affect the proliferation of human umbilical vein endothelial cells (HUVECs); however, it did inhibit VEGF‐ or bFGF‐stimulated HUVEC migration. To clarify the mechanism of this inhibitory effect, we examined the adhesion of HUVECs to extracellular matrix proteins. VSGP/F‐spondin specifically inhibited the spreading of HUVECs on vitronectin via the functional blockade of integrin αvβ3. As a result, VSGP/F‐spondin inhibited the tyrosine phosphorylation of focal adhesion kinase (FAK) when HUVECs were plated on vitronectin. Moreover, VSGP/F‐spondin inhibited the activation of Akt when HUVECs on vitronectin were stimulated with VEGF. VSGP/F‐spondin inhibited tube formation by HUVECs in vitro and neovascularization in the rat cornea in vivo. These results indicate that VSGP/F‐spondin inhibits angiogenesis at least in part by the blockade of endothelial integrin αvβ3.

expression and epigenetic change of the AR and FsHR Genes in the Granulosa cells of endometriosis patients

Background Endometriosis is one of the most common gynecological diseases associated with infertility. Endometriosis may affect the androgen receptor (AR) mRNA expression in human granulosa cells and the methylation of the promoter region of AR. We investigated 28 patients with endometriosis and 47 subjects without endometriosis undertaking IVF treatment. Methods Granulosa cells were obtained from 28 patients with endometriosis and 47 subjects without endometriosis as a control. Expressions of AR and FSHR mRNA were then evaluated by OneStep real-time PCR analysis, and the level of methylation of the promoter region was qualified by methylation-specified PCR (MSP). Results The expression of AR mRNA in the endometriosis group was statistically lower than that in the control group. As well, FSHR mRNA expression in the control group showed a positive correlation with AR mRNA expression; however, there was no such correlation in endometriosis patients. In the control group, AR mRNA expression was statistically higher in pregnant subjects compared with non-pregnant subjects; however, in the endometriosis group, no significant difference was identified. The promoter of AR was heavily methylated in all endometriosis cases; however, only 5 (45.4%) were methylated in the control group. Conclusion Lower AR mRNA expression and methylation of the AR promoter region might affect the expression of AR and FSHR the presence of endometriosis, thus leading to a disturbance in the regulation of AR and FSHR.