The Preliminary Study Of The Location And Function Of Exo70in The Rat Vascular Smooth Muscle Cells

Atherosclerosis (AS) is a progressive disease that serious threat the health of thehuman health, its pathogenesis has been a research hotspot. During atherogenesis,platelet-derived growth factor (PDGF)which secreted by the endothelium willpromote the phenotype changes of vascular smooth muscle cells (VSMCs)within themedial layer of the vessel wall from the quiescent contractile state to the activesynthetic state,proliferateand migrate from medial to the intima,subsequentlyparticipate in the formation of foam cells and plaque.The exocyst is an octameric protein complex that is essential for exocytosis.Exo70is the key subunit of exocyst complex which is broadly expressed in the yeast,mammalian and plant cells. In yeast and mammalian cells,Exo70is involved in theanchorage and fusion of transport vesicles with the plasma membrane during thesecretion. In addition, in the mammalian cells it also participates in a variety ofimportant physiological processes such as the cell migration, cell junctionformation and so on.In this experiment, the experimental subjects are the cultured rat aortic vascularsmooth muscle cell line A7r5and established rat atherosclerosis model. Theexperiment research the expression and localization of Exo70in rat vascular smoothmuscle cell line A7r5,the localization of Exo70in the process of the migration ofA7r5and the expression of Exo70in the process of AS that induced by fat dietthrough immunofluorescence staining, RT-PCR, and frozen sections experimentaltechniques designed to clear Exo70expression characteristics in VSMC and the rolein the process of VSMC migration and in order to find a new participation factorsduring AS progress, then provide a new target for atherosclerosis treatment.The main results are as follows:1.The expression of Exo70in rat aortic vascular smooth muscle cell line A7r5In view of the reported literature no Exo70expression in vascular smooth muscle cells, so the paper first research the expression of Exo70in A7r5cell lines. The resultof PCR shows that Exo70indeed express at the mRNA level. Immunofluorescencetestresults also show that Exo70expression A7r5cells and mainly distributed in thecytoplasm.2.Theposition of Exo70in rat aortic vascular smooth muscle cell line A7r5After determined the expression of Exo70in A7r5cells, papers usingimmunofluorescence labeling the position of Exo70in A7r5. The results showed thatExo70colocalizationwith Actin, but the phenomenonof colocalizationwith Tublin isnot obvious. Actin polymerization cytochalasin B treated cells, changes in theintracellular Actin polymerization, then Exo70was dispersed in the cytoplasm, whichExo70function may be dependent on microfilament achieve.3.Theposition of Exo70in rataortic vascular smooth muscle cell line A7r5duringmigrating processPapers use immunofluorescence labeling studied the position of Exo70in A7r5during scratch healing migration process. Experimental results show that at the edgeof the migrating A7r5cells, there is a focus of the Actin and Exo70exists significantcolocalizationwith Actin at this point. This shows that, Exo70involved inthemigration process in A7r5cell.4.Thechanges of Exo70expression in the process of atherosclerosisIn order to further clarify the expression changesof Exo70in the process ofatherosclerosis, the paper first build atherosclerosis rat model, usingimmunohistochemical staining technique observe the expressionof Exo70in thelesion area. The results showed thatExo70also express in rat aortic vascular smoothmuscle cells,and the expression level as the experimental animals arteryatherosclerotic plaque aggravating increase. Exo70expression levels than normalvascular tissue has a significant increase in the plaque area.Based on the experimental results, we believe that Exo70involved in aorticvascular smooth muscle migration and the formation of atherosclerotic plaque. ASmultiple factors involved in complex disease process of VSMC migration and foamplay an important role in the process of plaque formation, we speculate that in VSMC migration process, Exo70interaction with Actin involved in the reorganization of theactin cytoskeleton as well as the formationof pseudopodiaand thereby affect the ASplaque formation process.