Objective: To explore the mechanism of osteoclast stimulatory transmembrane protein (OC-STAMP) overexpression on epithelial-mesenchymal transition (EMT) . Methods: In April 2021, mice alveolar type Ⅱ epithelial cells MLE-12 were divided into five groups: overexpression control group (NC group), Ocstamp overexpression group (over-Ocstamp group), Fasudil intervention group (over-Ocstamp+Fasudil group), silence control group (si-NC group), Ocstamp silence group (si-Ocstamp group). The protein expressions of OC-STAMP, epithelial marker protein-E-cadherin (E-cad), interstitial marker protein-α-smooth muscle actin (α-SMA), Ras homolog gene family member A (RhoA), Rho GDP dissociation inhibitor α (Rho GDIα), Rho-associated protein kinase (ROCK), phosphate myosin phosphatase (p-MYPT) were examined by Western blotting and Immunocytochemical staining. The filamentous actin (F-actin) was detected by Phalloidin method. t test was used to compare the relative expression of each protein between the two groups. Results: Western blotting and Immunocytochemical staining showed that compared with the NC group, the expression level of E-cad was down-regulated, while the expression levels of α-SMA, Rho GDIα, RhoA, ROCK, p-MYPT were increased, and F-actin expression was enhanced in the over-Ocstamp group. The differences were statistically significant (P<0.05). There were no significant differences in E-cad and α-SMA protein expression in si-Ocstamp group compared with si-NC group (P>0.05). Compared with over-Ocstamp group, the expression level of E-cad protein in over-Ocstamp+Fasudil group was up-regulated, the expression levels of α-SMA, Rho GDIα, RhoA, ROCK and p-MYPT protein were decreased, and F-actin expression was weakened, with statistical significance (P<0.05) . Conclusion: OC-STAMP overexpression in alveolar type Ⅱ epithelial cells may induce actin cytoskeleton remodeling through activation of Rho GDIα/RhoA/ROCK signaling pathway, thus promoting EMT.
目的： 探讨过表达破骨细胞刺激性转膜蛋白（osteoclast stimulatory transmembrane protein，OC-STAMP）对上皮-间质转化的作用及机制。 方法： 于2021年4月，将小鼠肺泡Ⅱ型上皮细胞MLE-12细胞分为过表达对照组（NC组）、Ocstamp过表达组（over-Ocstamp组）、法舒地尔（Fasudil）干预组（over-Ocstamp+Fasudil组）、沉默对照组（si-NC组）、Ocstamp沉默组（si-Ocstamp组）。采用蛋白免疫印迹（Western blotting）法、免疫细胞化学染色法检测OC-STAMP、上皮标志蛋白E-钙黏蛋白（E-cadherin，E-cad）、间质标志蛋白α-平滑肌肌动蛋白（α-smooth muscle actin，α-SMA）、Ras基因家族成员A（Ras homolog gene family member A，RhoA）、Rho GDP解离抑制因子α（Rho GDP dissociation inhibitor α，Rho GDIα）、Rho相关蛋白激酶（Rho-associated protein kinase，ROCK）、磷酸化肌球蛋白磷酸酶（phosphate myosin phosphatase，p-MYPT）蛋白表达，采用鬼笔环肽法检测细胞骨架肌动蛋白（filamentous actin，f-actin）的变化。采用t检验比较两组间各蛋白的相对表达量。 结果： Western blotting及免疫细胞化学染色法结果显示，与NC组比较，over-Ocstamp组E-cad蛋白表达下调，α-SMA、Rho GDIα、RhoA、ROCK、p-MYPT蛋白表达增加，F-actin表达增强，差异均有统计学意义（P<0.05）；与si-NC组比较，si-Ocstamp组E-cad和α-SMA蛋白表达差异均无统计学意义（P>0.05）；与over-Ocstamp组比较，over-Ocstamp+Fasudil组E-cad蛋白表达上调，α-SMA、Rho GDIα、RhoA、ROCK、p-MYPT蛋白表达下降，F-actin表达减弱，差异均有统计学意义（P<0.05）。 结论： 肺泡Ⅱ型上皮细胞过表达OC-STAMP，可能通过激活Rho GDIα/RhoA/ROCK信号通路，诱导肌动蛋白细胞骨架重塑，进而促进上皮-间质转化。.
Keywords: Actin; Epithelial-mesenchymal transition; Osteoclast stimulatory transmembrane protein; Silicosis.