PTEN Regulated The Senscence Of Alveolar Epithelial Cells Through NF-κB Signal Pathway

Background:Idiopathic pulmonary fibrosis(IPF)is a chronic,progressive,and usually fatal lung disease which cannot be cured by any treatment so far and its pathogenesis is also unclear.It is accepted that IPF is an aging-related disease.So we may find new targets in senescence of AEC to improve the treatment of IPF.Purpose:Many researchers found out that accelerated senescence or premature aging exited in alveolar epithelial cells(AEC)during pathogenesis of IPF.Our research aimed to verify that whether the loss of PTEN trigger the senescence of AEC to mediate the pathogenesis of IPF through activating NF-κB signal.Methods:We carried out the following research with A549 cells,which have similar characteristics with type II AEC,and human lung tissue of IPF.(1)Aging model of AEC:Different concentration of bleomycin were added to induce the senescence of AEC for 5 days,then several markers of senescence such as protein P16,P21,SA-β-gal were tested;PTEN expression in the model:After the model established successfully,expression of PTEN and NF-κB-associated proteins was measured by Western blot.(2)Role of PTEN in the model:Lentivirus vector was applied to transfect the AEC to up-regulate and knock out the expression of PTEN respectively,then bleomycin were added to stimulate cells.After 5 days,PTEN expression and aging markers were examined Western blot was conducted to test the expression of P16,P21,NF-κB-associated protein.(3)Role of NF-κB in the model:Lentivirus vector was applied to transfect the AEC to knock out the expression of NF-κB respectively,or treated with the inhibitor of IκBα(BMS-345541),and then bleomycin were added to stimulate cells.After 5 days,NF-κB expression and aging markers were measured.Western blot was conducted to test the expression of P16,P21 proteins.(4)P16,P21 and PTEN expression in human lung tissue of IPF:The lung samples were obtained from lung transplantation of IPF patients and normal lung tissues from lung cancer patients.The expression of P16,P21,PTEN and expression of NF-κB-associated proteins in human lung tissue were measured by Western blot.Results:(1)Aging markers were increased gradually along with the increasing of bleomycin.The expression of PTEN was decreased and the NF-κB signal was activated gradually in the model with the increasing of bleomycin.(2)Overexpression and silence of PTEN can relieve and induce aging of AEC respectively.Silence of PTEN can leading to activate NF-κB signal.(3)Silence of NF-κB or reduced the activation of NF-κB signals can reduce aging of AEC respectively.(4)P16,P21 was increased and PTEN was decreased significantly in lung samples of IPF patients.Conclusion:The loss of PTEN trigger the senescence of AEC to mediate the pathogenesis of IPF through activating NF-κB signal.