N-acetyl Glucosaminyl Transferase-V Regulated Endothelial Cells Biological Effect VIA B1-integrin And VE-cadherin

Vascular endothelium is continuous coverage in systemic vascularintima cell populations, studies have found endothelial layer is not onlyblood and tissue barrier, but also possesses a variety of other functions,such as the reduction of vascular permeability, regulation of tissue andblood plasma component and material exchange, prevention of thecomposition of plasma and blood cells of disordered intrusion; theregulation of vascular smooth muscle function, synthesis and secretionregulation of vascular smooth muscle relaxation and contraction relatedfactor; the inhibition of vascular wall cells migration and proliferation. Inview of the physiological function of vascular endothelial cells, vascularendothelial cells injury become actuating link of many diseases such asatherosclerosis, hypertension, diabetes and so on. Therefore, looking for theaccount of vascular endothelial cells injury prove to be the therapy forcardiovascular disease. This paper mainly discusses the biological functionof vascular endothelial cells changes, which may be exist VE-cadherin,β1-integrin Vascular such glycosylation control" switch", and utilizing the effect ofVascular GnT-Ⅴcatalysis on distrisbuting VE-cadherin and β1-integrinN-glycan abundance to modulate endothelial cell function.Part one: N-acetylglucosaminyltransferase Ⅴ expression is regulatedby cell-cell adhesion via the VE-cadherinIn the present study, we aim to find the regulatory mechanismbetween VE-cadherin expression and the remodeling of itsoligosaccharides structures GnT-Ⅴ on EA.hy926cells. We haveexplored that when cells were exposed to IL-1β alone, the level ofGnT-V and its bisected N-glycan were decreased, which result indown-regulating of VE-cadherin N-glycosylation. Nevertheless theexpression of total VE-cadherin was reduced and so as to β-cateninshed from VE-cadherin–catenin complex, Which means the cell-celljunction was impaired, so that the amount of circulating leukocytesadhered to endothelial cells were growing. Moreover, we also foundthat VE-cadherin was the target of GnT-V. To investigate whetherGnT-V was directly participated in regulating VE-cadherinexpression,we utilized shRNA knockdown of GnT-Ⅴ. We gained thesame results, which were in line with cells exposure to IL-1β.Incontrast, overexpression of GnT-Ⅴ led to opposing effect to EA.hy926cells knockdown of GnT-Ⅴ genes. However, all the phenomenon could be reversed when GnT-Ⅴ stable transfected cells werestimulated with IL-1β for24h.Taken together, our results confirm thatVE-cadherin activity were regulated by GnT-Ⅴ. In addition, high levelof GnT-Ⅴ may be display a protective effect to Vascular endothelial.Our context opens new insights into the post-transcriptionalmodifications of VE-cadherin.Part two: Interleukin-1β induced vascular endothelial cells EA.hy926apoptosis via N-glycosylation modification on β1-integrin proteinIL-1β，one of interleukin1cytokine family member, is the veryimportant inflammatory cytokines, which mediates the inflammatoryprocess. Researches had shown that IL-1β could lead to vascularendothelial dysfunction. Recognizing the mechanism of cell functionaldisorder will provide a good theoretical basis for atherosclerosis. Toinvestigate the effect of IL-1β in damaging human vascular endothelialcells (EA.hy926), EA.hy926vascular endothelial cells (VEC) were used asits object. After treated with different concentration of IL-1β for24h, theeffect of IL-1β on the levels of β1-integrin, Bcl-2, Bax, Caspase-3andGnT-Ⅴ were detected by western blot. The effects of IL-1β on GnT-Ⅴproduct in the whole glycoprotein lysate were examined by lectin blot.Immunoprecipitation was used to test GnT-Ⅴ product (L-PHA reactivity)on β1-integrin glycoprotein induced by IL-1β. Cell apoptosis rate wasdetected by flow cytometry. IL-1β promotes β1-integrin expression at protein translation level. Moreover, it can downregulate the Bcl-2/Bax ratio,increase Caspase-3expression. Apoptosis of vascular endothelial cellsinduced by IL-1β may be mediated by N-glycosylation modification of β1-integrinIL-1β induced EA.hy926apoptosis via N-glycosylation modificationon β1-integrin protein, which cause dysfunction of vascular endothelial.