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ABSTRACT: Angiogenesis plays remarkable roles in the development of atherosclerotic rupture plaques. However, its essential mechanism remains unclear. The purpose of the study was to investigate whether inhibitor of DNA binding-1 or inhibitor of differentiation 1 (Id1) promoted angiogenesis when exposed to oxidised low-density lipoprotein (oxLDL), and to determine the molecular mechanism involved. Using aortic ring assay and tube formation assay as a model system, a low concentration of oxLDL was found to induce angiogenic sprouting and capillary lumen formation of endothelial cell. But the Id1 expression was significantly upregulated by oxLDL at low and high concentrations. The Id1 was localised in the nuclei of the human umbilical vein endothelial cells in the control group and in the high-concentration oxLDL group. Id1 was translocated to the cytoplasm at low oxLDL concentrations. The nucleocytoplasmic shuttling at low oxLDL concentration was inhibited by treatment with the nuclear export inhibitor leptomycin B. Protein kinase A (PKA) inhibitor H89 promoted nuclear export of Id1, and phosphatidylinositol-3-kinase (PI3K) inhibitor LY294002 reduced the nuclear export of Id1. PI3K inhibition blocked oxLDL-induced angiogenesis. Low concentrations of oxLDL promoted angiogenic sprouting and capillary formation. And this process depends on nuclear export of Id1, which in turn is controlled by the PI3K pathway. This report presents a new link between oxLDL and Id1 localisation, and may provide a new insight into the interactions of ox-LDL and Id1 in the context of atherosclerosis.
Biochimica et Biophysica Acta 07/2012; 1821(10):1361-9. · 4.66 Impact Factor
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ABSTRACT: Cerebral cavernous malformation (CCM) is a common vascular disease in central nervous system that frequently predisposes to stroke, seizure, and cerebral hemorrhage. CCM lesions are characterized by dilated and leaky intracranial capillaries composed of a thin layer of vascular endothelial cells with abnormal subendothelial extracellular matrix. Despite the understanding that genetic mutation of three CCM genes (CCM1, CCM2, and CCM3) results in hereditary CCM, the molecular mechanism underlying vascular defects in CCM lesions remains poorly understood. Recent studies have shown that integrin cytoplasmic domain-associated protein-1 (ICAP-1, also known as integrin β1 binding protein1, ITGB1BP), a cytoplasmic protein interacting with both β1 integrin subunit and CCM1 protein (also known as Krit1), is implicated in vascular development. Analysis of data on the biochemistry and cellular biology of ICAP-1 highlights that bidirectional interaction of ICAP-1 with CCM1 and integrin might regulate diverse pathological processes of CCM disorder. Specifically, emerging evidence supports the hypothesized involvement of ICAP-1 in CCM pathogenesis through its significant effect in attenuating excessive vascular growth, its indispensable function in activating CCM1 protein, and its essential role in regulating integrin functions.
Journal of Neurology 06/2012; · 3.47 Impact Factor
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ABSTRACT: The inhibitor of differentiation 1 (Id1) protein is required for tubulogenesis, but the molecular signalling pathways remain unclear. Overexpression (Id1-t) or down-regulation (si-Id1) of Id-1 in cell lines, were used to study the function of Id1. The expression of Id1 and β1-integrin was assessed by Western blotting. Up-regulation of Id1 in human umbilical vascular endothelial cells (HUVECs) activated the expression of β1-integrin and promoted cell adhesion and spreading. Conversely, down-regulation of Id1 suppressed β1-integrin expression and inhibited tubulogenesis. By using a β1-integrin antibody to inhibit β1-integrin function, we demonstrated that Id1-induced cell adhesion and tubulogenesis were mediated by β1-integrin. In addition, HUVECs overexpressing Id1 were able to promote capillary tube formation through cytoskeleton reorganization and cell contraction. Finally, the Rho-kinase inhibitor Y27632 inhibited tubulo-genesis induced by Id1. Our findings provide evidence that Id1 regulates tubulogenesis in vitro through β1-integrin and Rho-kinase signalling.
International Journal of Molecular Medicine 10/2011; 28(4):543-8. · 1.98 Impact Factor
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ABSTRACT: Considering that oxidized low-density lipoprotein (ox-LDL) may inhibit endothelial cell (EC) migration and proliferation during endothelialization, we hypothesize that the Id1 protein promotes endothelialization exposed to ox-LDL. Cell proliferation was evaluated by cell counts, and cell migration was evaluated by wound closure assay. The role of Id1 in the cell migration and proliferation was appraised through building Id1 overexpression and silencing ECs. Here, we report that Id1 in human umbilical vascular ECs (HUVECs) was up-regulated by ox-LDL in a dose- and time-dependent manner. Low concentrations of ox-LDL increased the proliferation and migration of EC. High concentrations of ox-LDL suppressed HUVECs proliferation and migration, whose inhibitory effects were abolished by Id1 over-expression. Attenuated proliferation and migration of ECs exposed to high concentrations of ox-LDL may be correlated with the nuclear localization of p53, which was obviously weakened by over-expression of Id1 and strengthened by silencing Id1. Collectively, changes in EC, comprising proliferation and migration, upon exposure to various concentrations of ox-LDL are, at least in part, attributed to the modulatory effect of the Id1 protein, which suggests that manipulating Id1 protein activity may offer therapeutic opportunities to promote re-endothelialization under high concentrations of ox-LDL.
Annals of biomedical engineering 08/2011; 39(12):2869-78. · 2.41 Impact Factor
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ABSTRACT: The Id1 protein is critical for endothelial cell angiogenesis, and this function is particularly relevant to cancer development, cardiovascular disease, and wound healing. We hypothesized that Id1 enhanced migration and tubulogenesis by controlling the expression and function of p53. In this study, we examined cell migration following Id1 overexpression and silencing endothelial cells. The results showed that overexpression of Id1 enhanced cell migration and increased beta1-integrin expression, but inhibition of beta1-integrin blocked motility even in clones overexpressing Id1, suggesting that Id1 regulated motility through beta1-integrin. Further analysis revealed that p53, whose expression and distribution is regulated by Id1, was critical for cell migration, and may be involved in regulating the expression of beta1-integrin. Inhibiting p53 function using PFT-α, a functional inhibitor of p53, increased the expression of beta1-integrin and promoted cell migration even in Id1-silencing endothelial cells, demonstrating that the Id1 knockdowns induced inhibition of endothelial cell migration and the expression of beta1-integrin were controlled by p53. In addition, Id1-p53 pathway regulated the cytoskeleton formation and tubulogenesis. These results demonstrate that Id1-induced beta1-integrin expression in endothelial cells and the function of Id1 in cell migration and tubulogenesis are dependent on p53.
Molecular and Cellular Biochemistry 06/2011; 357(1-2):125-33. · 2.06 Impact Factor
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ABSTRACT: Plaque neovascularization and inflammation are responsible for plaque destabilization and rupture. However, the precise triggers for inflammation and neovascularization in atherosclerosis are largely unknown. Id1 (inhibitor of DNA-binding) protein is a helix-loop-helix transcription factor and plays an important role in angiogenesis and inflammation. The expression of Id1 can be up-regulated by plaque formation factors such as vascular endothelial growth factor (VEGF), hypoxia, NAD(P)H oxidase, and TNF-alpha. Moreover, Id1 is critical to endothelial progenitor cell (EPC) population formation and angiogenesis. Evidence from diverse sources has suggested that Id1 may affect plaque destabilization through angiogenesis and inflammation. Herein we hypothesize that Id1 is an important protein for the development and progression of atherosclerotic plaque destabilization and hence blocking the expression of Id1 may serve as new targets for antiatherogenic therapy.
Medical Hypotheses 01/2011; 76(5):627-8. · 1.39 Impact Factor
