Abdul-Hafez Amal, Mohamed Tarek, Uhal Bruce D
Department of Pediatrics and Human Development, Michigan State University, USA.
Department of Physiology, Michigan State University, USA.
J Lung Pulm Respir Res. 2019;6(3):58-62. Epub 2019 Jul 18.
Neonatal therapy with a high concentration of oxygen (hyperoxia) is a known cause of bronchopulmonary dysplasia (BPD). BPD is characterized by increased pulmonary permeability and diffuse infiltration of various inflammatory cells. Disruption of the epithelial barrier may lead to altered pulmonary permeability and airways fluid accumulation. Mas receptor is a component of the renin angiotensin system and is the receptor for the protective endogenous peptide angiotensin 1-7. The activation of the Mas receptor was previously shown to have protective pulmonary responses. However, the effect of Mas receptor activation on epithelial barrier integrity has not been tested.
To determine the effects of hyperoxia with or without Mas receptor activation on epithelial cell barrier integrity.
DESIGN/METHODS: Human epithelial cell line A549 was cultured on transwell polycarbonate porous membrane to confluence and treated with 95% oxygen (hyperoxia) for 72 hours with or without the Mas receptor agonist (AVE0991), or the apoptotic inhibitors Z-VAD-FMK or aurintricarboxylic acid. The cells were then challenged with Rhodamine labeled bovine serum albumin (Rh-BSA) on one side of the membrane. Fluorescent quantitation of Rh-BSA (albumin flux) was performed on the media in the other side of the membrane 3 hours later and was compared with 21% oxygen (Normoxia) control group. A549 cells were also cultured with or without AVE0991 in hyperoxia or normoxia and used for nuclear fragmentation apoptosis assay using propidium iodide staining.
Hyperoxia induced an increase in albumin flux that was significantly prevented by AVE0991 treatment and by the apoptosis inhibitors. AVE0991 also significantly decreased the hyperoxia-induced nuclear fragmentation.
These results suggest that hyperoxia causes a disruption in the epithelial barrier integrity, and that this disruption is inhibited by the Mas receptor agonist AVE0991 through inhibition of epithelial apoptosis. These results reveal a novel potential drug for BPD and pulmonary edema treatment.
新生儿高浓度氧疗（高氧）是支气管肺发育不良（BPD）的已知病因。BPD的特征是肺通透性增加和各种炎性细胞的弥漫性浸润。上皮屏障的破坏可能导致肺通透性改变和气道积液。Mas受体是肾素血管紧张素系统的一个组成部分，是内源性保护肽血管紧张素1-7的受体。先前已表明Mas受体的激活具有保护性肺反应。然而，Mas受体激活对上皮屏障完整性的影响尚未得到测试。
确定有或没有Mas受体激活的高氧对上皮细胞屏障完整性的影响。
设计/方法：将人上皮细胞系A549培养在Transwell聚碳酸酯多孔膜上至汇合，并用95%氧气（高氧）处理72小时，同时有或没有Mas受体激动剂（AVE0991），或凋亡抑制剂Z-VAD-FMK或金精三羧酸。然后在膜的一侧用罗丹明标记的牛血清白蛋白（Rh-BSA）刺激细胞。3小时后，对膜另一侧培养基中的Rh-BSA（白蛋白通量）进行荧光定量，并与21%氧气（常氧）对照组进行比较。A549细胞也在高氧或常氧条件下有或没有AVE0991培养，并用于使用碘化丙啶染色的核碎裂凋亡检测。
高氧诱导白蛋白通量增加，AVE0991处理和凋亡抑制剂可显著阻止这种增加。AVE0991还显著减少了高氧诱导的核碎裂。
这些结果表明，高氧导致上皮屏障完整性破坏，而Mas受体激动剂AVE0991通过抑制上皮细胞凋亡抑制这种破坏。这些结果揭示了一种用于治疗BPD和肺水肿的新型潜在药物。
