Research Of P21Protein Subcellular Localization In Human Bronchial Epithelial Cells Apoptosis Induced By TGF-β1

Background:P21is a kind of cell cycle control protein which can inhibits the cell cycleprogress.However, Some researches confirm which involve in cell senescence、apoptosis、 differentiation. There is a close relationship between apoptosis and itssubcellular localization.It has adverse functions in cytoplasm and nucleus.itoverexpress can promote cell apoptosis in nuclear,but inhibit apoptosis in thecytoplasm.Human bronchial epithelial cells are the first airway barrier. It has protectiveeffect on airway,and can also secrete cytokines. The imbalance between proapoptosisand anti-apoptosis can lead to many lung diseases, such as COPD、 asthma、pulmonary fibrosis、 acute lung injury.TGF-β1is a multifunctional cytokine, involved in cell growth、differentiation、cell cycle、apoptosis. Accord to some researches, It can stimulate apoptosis of lungepithelial cells, and can simultaneously increase P21protein expression,overexpression of P21protein protects TGF-β1from apoptosis of lung epithelialcells. This researcher pay attention to the relation between apoptosis and subcellularlocalization of P21by TGF-β1.Objective:Study on the relationship between subcellular localization of P21in the TGF-β1induction apoptosis of human bronchial epithelial cell line (16HBE).Method.TGF-β1stimulates apoptosis of16HBE cell, and then extract protein fromcytoplasmic and nuclear, measure P21protein in the cytoplasm and nucleus bywestern blot semi-quantitative assessment.Result.1.TGF-β1at different concentrations (0.3ng/ml,1ng/ml,3ng/ml,10ng/ml,33ng/ml); at different time (12h,24h,48h) can induce16HBE cell apoptosis.16HBEcell apoptosis in dose-dependent and time-dependent, in TGF-β1dose≤10ng/ml, time≤24hour. However, late apoptotic and dead cells obviously increase in TGF-β1dose(33ng/ml)or time(48h).2. TGF-β1stimulate24h in concentration (3ng/ml,10ng/ml),the P21proteinexpression in the cytoplasm and the nucleus were significantly higher than controlgrop (P<0.05); no difference in the nucleus p21protein (P>0.05)(3ng/ml,10ng/ml); The p21protein more express in the cytoplasm than the nucleus in thesame dose of TGF-β1（P<0.05）；cytoplasm P21protein decrease accompanyincrease apoptosis,which relates to cytoplasm P21protein anti-apoptosis role.Conclusion:The research shows that the TGF-β1in human bronchial epithelial cell apoptosiscan cause cytoplasmic nuclear localization of P21.