Clec14a is specifically expressed in endothelial cells and mediates cell to cell adhesion
ABSTRACT Clec14a is a member of the thrombomodulin (TM) family, but its function has not yet been determined. Here, we report that Clec14a is a plasma membrane protein of endothelial cells (ECs) expressed specifically in the vasculature of mice. Deletion mutant analysis revealed that Clec14a mediates cell-cell adhesion through its C-type lectin-like domain. Knockdown of Clec14a in ECs suppressed cell migratory activity and filopodial protrusion, and delayed formation of tube-like structures. These findings demonstrate that Clec14a is a novel EC-specific protein that appears to play a role in cell-cell adhesion and angiogenesis.
SourceAvailable from: Hironobu Ihn[Show abstract] [Hide abstract]
ABSTRACT: Endothelin (ET)-1 is known for the most potent vasoconstrictive peptide that is released mainly from endothelial cells. Several studies have reported ET-1 signaling is involved in the process of wound healing or fibrosis as well as vasodilation. However, little is known about the role of ET-1 in these processes. To clarify its mechanism, we compared skin fibrogenesis and wound repair between vascular endothelial cell-specific ET-1 knockout mice and their wild-type littermates. Bleomycin-injected fibrotic skin of the knockout mice showed significantly decreased skin thickness and collagen content compared to that of wild-type mice, indicating that bleomycin-induced skin fibrosis is attenuated in the knockout mice. The mRNA levels of transforming growth factor (TGF)-β were decreased in the bleomycin-treated skin of ET-1 knockout mice. On the other hand, skin wound healing was accelerated in ET-1 knockout mice, which was indicated by earlier granulation tissue reduction and re-epithelialization in these mice. The mRNA levels of TGF-β, tumor necrosis factor (TNF)-α and connective tissue growth factor (CTGF) were reduced in the wound of ET-1 knockout mice. In endothelial ET-1 knockout mouse, the expression of TNF-α, CTGF and TGF-β was down-regulated. Bosentan, an antagonist of dual ET receptors, is known to attenuate skin fibrosis and accelerate wound healing in systemic sclerosis, and such contradictory effect may be mediated by above molecules. The endothelial cell-derived ET-1 is the potent therapeutic target in fibrosis or wound healing, and investigations of the overall regulatory mechanisms of these pathological conditions by ET-1 may lead to a new therapeutic approach.PLoS ONE 05/2014; 9(5):e97972. DOI:10.1371/journal.pone.0097972 · 3.53 Impact Factor
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ABSTRACT: Proteomics has been successfully used for cell culture on dishes, but more complex cellular systems have proven to be challenging and so far poorly approached with proteomics. Because of the complexity of the angiogenic program, we still do not have a complete understanding of the molecular mechanisms involved in this process, and there have been no in depth quantitative proteomic studies. Plating endothelial cells on matrigel recapitulates aspects of vessel growth, and here we investigate this mechanism by using a spike-in SILAC quantitative proteomic approach. By comparing proteomic changes in primary human endothelial cells morphogenesis on matrigel to general adhesion mechanisms in cells spreading on culture dish, we pinpoint pathways and proteins modulated by endothelial cells. The cell-extracellular matrix adhesion proteome depends on the adhesion substrate, and a detailed proteomic profile of the extracellular matrix secreted by endothelial cells identified CLEC14A as a matrix component, which binds to MMRN2. We verify deregulated levels of these proteins during tumor angiogenesis in models of multi-stage carcinogenesis. This is the most in depth quantitative proteomic study of endothelial cell morphogenesis, which shows the potential of applying high accuracy quantitative proteomics to in vitro models of vessel growth to shed new light on mechanisms that accompany pathological angiogenesis.Molecular & Cellular Proteomics 08/2013; 12(12). DOI:10.1074/mcp.M113.031344 · 7.25 Impact Factor
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ABSTRACT: Epithelial cell-cell contacts maintain normal glandular tissue homeostasis and their breakage can trigger epithelial-to-mesenchymal transition (EMT), a fundamental step in the development of metastatic cancer. Despite the ability of C-type lectin domains (CTLDs) to modulate cell-cell adhesion it is not known if they modulate epithelial adhesion in EMT and tumor progression. Here the multi-CTLD mannose receptor, Endo180 (MRC2/uPARAP), was shown using Kaplan-Meier analysis to be predictive of survival outcome in men with early prostate cancer. A proteomic screen of novel interaction partners with the fourth CTLD (CTLD4) in Endo180 revealed that its complex with CD147 is indispensable for the stability of three-dimensional (3D) acini formed by non-transformed prostate epithelial cells (PECs). Mechanistic study using knockdown of Endo180 or CD147, and treatment with an Endo180 monoclonal antibody (mAb) targeting CTLD4 (clone 39.10), or a dominant-negative GST-CTLD4 chimeric protein, induced scattering of PECs associated with internalization of Endo180 into endosomes, loss of E-cadherin (CDH1/ECAD) and unzipping of cell-cell junctions. These findings are the first to demonstrate that a CTLD acts as a suppressor and regulatory switch for EMT; thus, positing that stabilization of Endo180-CD147 complex is a viable therapeutic strategy to improve rates of prostate cancer survival. Implications: This study identifies the interaction between CTLD4 in Endo180 and CD147 as an EMT suppressor and indicates that stabilization of this molecular complex improves prostate cancer survival rates.Molecular Cancer Research 11/2014; DOI:10.1158/1541-7786.MCR-14-0344-T · 4.50 Impact Factor