Rationale: Vascular endothelial growth factor (VEGF), a major proangiogenic agent, exerts its proangiogenic action by binding to VEGF receptor 2 (VEGFR2), the activity of which is regulated by direct interactions with other cell surface proteins, including integrin ␣ V ␤ 3 . However, how the interaction between VEGFR2 and integrin ␣ V ␤ 3 is regulated is not clear. Objective:To investigate whether Necl-5/poliovirus receptor, an immunoglobulin-like molecule that is known to bind integrin ␣ V ␤ 3 , regulates the interaction between VEGFR2 and integrin ␣ V ␤ 3 , and to clarify the role of Necl-5 in the VEGF-induced angiogenesis. Key Words: cell adhesion molecules Ⅲ angiogenesis Ⅲ peripheral vascular disease A ngiogenesis plays an important role in diverse developmental, physiological, and pathological processes. Angiogenesis is triggered by the interaction of proangiogenic growth factors and extracellular matrix with their receptors. Vascular endothelial growth factor (VEGF) is a major proangiogenic agent that regulates multiple key steps of angiogenesis. VEGF exerts its proangiogenic action by binding to VEGF receptor 2 (VEGFR2). The activity of VEGFR2 is regulated by direct interactions with other cell surface proteins, such as coreceptor neuropilins 1 and adhesion molecules, including VE-cadherin 2 and integrins. 3 Integrins, including integrin ␣ V ␤ 3 , are critically involved in angiogenesis and initiate signals that control cell migration, proliferation, and survival. 4 Receptors such as VEGFR2 and plateletderived growth factor (PDGF) receptor (PDGFR) interact with integrins, and these interactions exhibit synergistic effects and cooperatively regulate diverse intracellular signals that control key cell functions. 3,5,6 However, how the interaction between VEGFR2 and integrin ␣ V ␤ 3 through their extracellular regions is regulated is not known. Methods and Results:Original received September 15, 2011; revision received January 12, 2012; accepted January 18, 2012. In December 2011 Nectins and nectin-like molecules (Necls) are immunoglobulinlike cell adhesion molecules that are essential for the formation of cell-cell adhesions, and these molecules regulate a variety of cellular functions, including cell polarization, differentiation, movement, proliferation, and survival. 7,8 Necls comprise a family with 5 members, Necl-1 to -5, and among these, Necl-5 exhibits distinctive expression profiles. Necl-5 was originally identified as human poliovirus receptor (PVR), also termed CD155, 9,10 and as rodent Tage4, which is overexpressed in rodent colon carcinoma. 11,12 Necl-5 is expressed ubiquitously, but its expression level is extremely low in most adult organs in rodents. 13,14 However, it becomes upregulated in the developing or regenerating liver 15,16 and transformed cells. 17,18 In NIH3T3 cells, Necl-5 forms a complex with integrin ␣ V ␤ 3 and PDGFR, and the formation of this complex enhances cell movement and proliferation. 19 However, the function of Necl-5 and its mode of action in vascular endothelial ...

Objective-Intimal thickening is considered to result from the dedifferentiation of medial smooth muscle cells (SMCs) from a contractile to a synthetic phenotype, and their subsequent migration and proliferation. It is unknown whether nectin-like molecule (Necl)-5, which is overexpressed in cancer cells, is involved in intimal thickening. Approach and Results-Necl-5 was upregulated in mouse carotid artery after ligation. Compared with wild-type mice, intimal thickening after carotid artery ligation was milder in Necl-5 knockout mice. In vitro, the expression levels of SMC differentiation markers were higher, whereas the expression level of an SMC dedifferentiation marker was lower, in Necl-5 knockout mouse aortic SMCs (MASMCs) compared with wild-type MASMCs. The migration, proliferation, and extracellular signal-regulated kinase activity in response to serum were decreased in Necl-5 knockout MASMCs compared with wild-type MASMCs. In wild-type MASMCs, inhibition of extracellular signal-regulated kinase activity increased the expression levels of SMC differentiation markers and decreased their migration and proliferation in response to serum. Conclusions-The

[Purpose] Endothelial lipase (EL) is a novel phospholipase which regulates serum high-density lipoprotein cholesterol (HDL-C) levels. In the present study, we have measured serum levels of EL in human subjects, and examined the effect of statins on serum HDL levels and EL mass. [Methods and Results] A sandwich ELISA for human EL was established using two monoclonal antibodies against amino- or carboxy-terminus of human EL. Serum EL concentrations were measured and compared with the serum lipid profile in 237 patients with cardiovascular diseases. There was no significant correlation between serum EL mass and age or gender. Serum EL levels were negatively associated with serum HDL-C levels, but not with serum LDL-C, total cholesterol, or triglyceride levels. Forty-eight patients with hypercholesterolemia were treated with pitavastatin for 6 months, and serum EL mass was evaluated before and after the pitavastatin treatment. Pitavastatin treatment significantly reduced serum EL levels by 15% and increased HDL-C levels by 12%. Complimentary cell culture experiments revealed that pitavastatin suppressed basal and cytokine-induced EL expression and phospholipase activities in endothelial cells, which is reversed by the concomitant treatment with mevalonate or geranylgeranylpyrophosphate. Also, overexpression of RhoA T19N, a dominant negative mutant of RhoA, decreased the EL expression. [Conclusion] EL is a determinant of serum HDL-C levels in humans. Pitavastatin reduced EL expression through the protein isoprenylation and inhibition of Rho activity, and raised serum HDL-C levels. Thus, EL would be a target molecule for the HDL-raising pharmaceutical interventions.