Ocstamp Overexpression Drives Lung Alveolar Epithelial Cell Type Ⅱ Senescence In Silicosis

Objective To investigate the mechanism of overexpressing osteoclast stimulating transmembrane protein（OC-STAMP）drives alveolar epithelial type II cell（AT2）senescence.Methods Using HOPE-MED8050 system to established the rats silicosis model,and treated with 4-phenylbutyric（4-PBA）.In vitro,we cultured the murine lung epithelial-12（MLE-12）and treated with Ocstamp overexpressed plasmid,Si O₂,4-PBA and other reagents,respectively.Western blot and real-time quantitative PCR were used to detect the expression of OC-STAMP in the lungs of silicosis rats,and western blot was used to detect the expression of senescence related proteins in the lungs of silicosis rats treated with 4-PBA.The expression levels of senescence related proteins,epithelial mesenchymal transformation（EMT）related proteins and endoplasmic reticulum stress（ER stress）related proteins were detected by immunofluorescence staining and western blot.β-galactosidase staining（β-Gal）was used to detect cell senescence.The interaction between OC-STAMP and MYH9 was detected by immunoprecipitation.Results 1 In normal alveolar area,macrophage alveolitis area,and cellular fibrous silicon nodule area in silicosis model rats,the percentage of ABCA3 positive cells was significantly upregulated（P<0.05）;Compared with the normal alveolar region,the percentage of VG staining area,PCNA and P21 positive cells in macrophage alveolitis region and cell fibrous silicon nodule region were gradually up-regulated（P<0.05）;In the alveolitis region,the PCNA positive percentage of macrophages was significantly higher than AT2 cells,while the P21 positive percentage of AT2 cells was significantly higher than macrophages（P<0.05）.2 Compared with the control group,OC-STAMP protein levels and m RNA expression levels were up-regulated in the lungs of silicosis rats（P<0.05）,immunofluorescence staining results showed that OC-STAMP could be located in AT2.Compared with silicosis model group,cell senescence and ER stress-related protein expression were down-regulated in 4-PBA treatment group（P<0.05）.3 Compared with the control group,the MLE-12 overexpressed Ocstamp MLE-12β-Gal staining was positive,and the expression levels of EMT,cell senescence and ER stress-related signaling proteins were up-regulated（P<0.05）;si RNA-Ocstamp or 4-PBA reversed these effects（P<0.05）.4 Immunoprecipitation showed that MYH9 could bind to OC-STAMP,si-Myh9could down-regulated the expression of senescence related proteins（P<0.05）.Conclusion Overexpression of Ocstamp drives EMT,ER stress and cell senescence in MLE-12 cells.Figure28;Table25;Reference 134...