Hou Yapeng, Li Jun, Ding Yan, Cui Yong, Nie Hongguang
Department of Stem Cells and Regenerative Medicine, College of Basic Medical Science, China Medical University, Shenyang, China.
Key Laboratory of Medical Electrophysiology, Ministry of Education & Medical Electrophysiological Key Laboratory of Sichuan Province (Collaborative Innovation Center for Prevention of Cardiovascular Diseases), Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China.
J Ethnopharmacol. 2022 Jan 10;282:114654. doi: 10.1016/j.jep.2021.114654. Epub 2021 Sep 16.
Luteolin (Lut) was recently identified as the major active ingredient of Mosla scabra, which was a typical representative traditional Chinese medicine and had been used to treat pulmonary diseases for thousands of years.
This study was to explore the effects and relative mechanisms of Lut in LPS-induced acute lung injury/acute respiratory distress syndrome (ALI/ARDS). The main characteristic of ALI/ARDS is pulmonary edema, and epithelial sodium channel (ENaC) is a key factor in effective removal of excessive alveolar edematous fluid, which is essential for repairing gas exchange and minimizing damage to the peripheral tissues. However, whether the therapeutic effects of Lut on respiratory diseases are relative with ENaC is still unknown.
Alveolar fluid clearance was calculated in BALB/c mice and ENaC function was measured in H441 cells. Moreover, ENaC membrane protein and mRNA were detected by Western blot and real-time PCR, respectively. We also studied the involvement of cGMP/PI3K pathway during the regulation of Lut on ENaC during LPS-induced ALI/ARDS by ELISA method and applying cGMP/PI3K inhibitors/siRNA.
The beneficial effects of Lut in ALI/ARDS were evidenced by the alleviation of pulmonary edema, and enhancement of both amiloride-sensitive alveolar fluid clearance and short-circuit currents. Lut could alleviate the LPS decreased expression levels of ENaC mRNA and membrane protein in H441 cells and mouse lung. In addition, cGMP concentration was increased after the administration of Lut in ALI/ARDS mice, while the inhibition of cGMP/PI3K pathway could abrogate the enhanced AFC and ENaC protein expression of Lut.
These results implied that Lut could attenuate pulmonary edema via enhancing the abundance of membrane ENaC at least partially through the cGMP/PI3K pathway, which could provide a promising therapeutic strategy for treating ALI/ARDS.
木犀草素（Lut）最近被确定为石荠苎的主要活性成分，石荠苎是一种典型的传统中药，数千年来一直用于治疗肺部疾病。
本研究旨在探讨Lut对脂多糖（LPS）诱导的急性肺损伤/急性呼吸窘迫综合征（ALI/ARDS）的影响及相关机制。ALI/ARDS的主要特征是肺水肿，上皮钠通道（ENaC）是有效清除过多肺泡水肿液的关键因素，这对于修复气体交换和最小化对周围组织的损伤至关重要。然而，Lut对呼吸系统疾病的治疗作用是否与ENaC相关仍不清楚。
在BALB/c小鼠中计算肺泡液体清除率，并在H441细胞中测量ENaC功能。此外，分别通过蛋白质免疫印迹法和实时聚合酶链反应检测ENaC膜蛋白和信使核糖核酸。我们还通过酶联免疫吸附测定法以及应用环磷酸鸟苷/磷脂酰肌醇-3激酶（cGMP/PI3K）抑制剂/小干扰RNA，研究了在LPS诱导的ALI/ARDS期间Lut对ENaC的调节过程中cGMP/PI3K途径的参与情况。
Lut在ALI/ARDS中的有益作用表现为肺水肿减轻、amiloride敏感性肺泡液体清除率和短路电流增加。Lut可减轻LPS降低的H441细胞和小鼠肺中ENaC信使核糖核酸和膜蛋白的表达水平。此外，在ALI/ARDS小鼠中给予Lut后环磷酸鸟苷浓度升高，而抑制cGMP/PI3K途径可消除Lut增强的肺泡液体清除率和ENaC蛋白表达。
这些结果表明，Lut至少部分通过cGMP/PI3K途径增强膜ENaC的丰度来减轻肺水肿，这可能为治疗ALI/ARDS提供一种有前景的治疗策略。
