Disayabutr Supparerk, Kim Eun Kyung, Cha Seung-Ick, Green Gary, Naikawadi Ram P, Jones Kirk D, Golden Jeffrey A, Schroeder Aaron, Matthay Michael A, Kukreja Jasleen, Erle David J, Collard Harold R, Wolters Paul J
Division of Pulmonary, Critical Care, Allergy and Sleep Medicine, Department of Medicine, University of California San Francisco, San Francisco, California, United States of America.
Department of Internal Medicine, CHA Bundang Medical Center, College of Medicine, CHA University, Seongnam, Korea.
PLoS One. 2016 Jun 30;11(6):e0158367. doi: 10.1371/journal.pone.0158367. eCollection 2016.
Pathologic features of idiopathic pulmonary fibrosis (IPF) include genetic predisposition, activation of the unfolded protein response, telomere attrition, and cellular senescence. The mechanisms leading to alveolar epithelial cell (AEC) senescence are poorly understood. MicroRNAs (miRNAs) have been reported as regulators of cellular senescence. Senescence markers including p16, p21, p53, and senescence-associated β-galactosidase (SA-βgal) activity were measured in type II AECs from IPF lungs and unused donor lungs. miRNAs were quantified in type II AECs using gene expression arrays and quantitative RT-PCR. Molecular markers of senescence (p16, p21, and p53) were elevated in IPF type II AECs. SA-βgal activity was detected in a greater percentage in type II AECs isolated from IPF patients (23.1%) compared to patients with other interstitial lung diseases (1.2%) or normal controls (0.8%). The relative levels of senescence-associated miRNAs miR-34a, miR-34b, and miR-34c, but not miR-20a, miR-29c, or miR-let-7f were significantly higher in type II AECs from IPF patients. Overexpression of miR-34a, miR-34b, or miR-34c in lung epithelial cells was associated with higher SA-βgal activity (27.8%, 35.1%, and 38.2%, respectively) relative to control treated cells (8.8%). Targets of miR-34 miRNAs, including E2F1, c-Myc, and cyclin E2, were lower in IPF type II AECs. These results show that markers of senescence are uniquely elevated in IPF type II AECs and suggest that the miR-34 family of miRNAs regulate senescence in IPF type II AECs.
特发性肺纤维化（IPF）的病理特征包括遗传易感性、未折叠蛋白反应的激活、端粒磨损和细胞衰老。导致肺泡上皮细胞（AEC）衰老的机制尚不清楚。据报道，微小RNA（miRNA）是细胞衰老的调节因子。在IPF肺组织和未使用的供体肺组织的II型AEC中检测了衰老标志物，包括p16、p21、p53和衰老相关β-半乳糖苷酶（SA-βgal）活性。使用基因表达阵列和定量RT-PCR对II型AEC中的miRNA进行定量。IPF II型AEC中衰老分子标志物（p16、p21和p53）升高。与其他间质性肺疾病患者（1.2%）或正常对照（0.8%）相比，从IPF患者分离的II型AEC中检测到SA-βgal活性的比例更高（23.1%）。IPF患者II型AEC中衰老相关miRNA miR-34a、miR-34b和miR-34c的相对水平显著高于miR-20a、miR-29c或miR-let-7f。相对于对照处理的细胞（8.8%），肺上皮细胞中miR-34a、miR-34b或miR-34c的过表达与更高的SA-βgal活性相关（分别为27.8%、35.1%和38.2%）。IPF II型AEC中miR-34 miRNA的靶标，包括E2F1、c-Myc和细胞周期蛋白E2较低。这些结果表明，衰老标志物在IPF II型AEC中独特地升高，并表明miR-34家族的miRNA调节IPF II型AEC中的衰老。
