Department of Pediatrics, University of Rochester, 601 Elmwood Avenue, Box 850, Rochester, NY, 14642, USA.
Department of Pharmacology and Physiology, University of Rochester, 601 Elmwood Avenue, Rochester, NY, 14642, USA.
Sci Rep. 2023 Apr 26;13(1):6792. doi: 10.1038/s41598-023-33985-4.
Acute Lung Injury/Acute Respiratory Distress Syndrome (ALI/ARDS) is characterized by diffuse alveolar damage and significant edema accumulation, which is associated with impaired alveolar fluid clearance (AFC) and alveolar-capillary barrier disruption, leading to acute respiratory failure. Our previous data showed that electroporation-mediated gene delivery of the Na, K-ATPase β1 subunit not only increased AFC, but also restored alveolar barrier function through upregulation of tight junction proteins, leading to treatment of LPS-induced ALI in mice. More importantly, our recent publication showed that gene delivery of MRCKα, the downstream effector of β1 subunit-mediated signaling towards upregulation of adhesive junctions and epithelial and endothelial barrier integrity, also provided therapeutic potential for ARDS treatment in vivo but without necessarily accelerating AFC, indicating that for ARDS treatment, improving alveolar capillary barrier function may be of more benefit than improving fluid clearance. In the present study, we investigated the therapeutical potential of β2 and β3 subunits, the other two β isoforms of Na, K-ATPase, for LPS-induced ALI. We found that gene transfer of either the β1, β2, or β3 subunits significantly increased AFC compared to the basal level in naïve animals and each gave similar increased AFC to each other. However, unlike that of the β1 subunit, gene transfer of the β2 or β3 subunit into pre-injured animal lungs failed to show the beneficial effects of attenuated histological damage, neutrophil infiltration, overall lung edema, or increased lung permeability, indicating that β2 or β3 gene delivery could not treat LPS induced lung injury. Further, while β1 gene transfer increased levels of key tight junction proteins in the lungs of injured mice, that of either the β2 or β3 subunit had no effect on levels of tight junction proteins. Taken together, this strongly suggests that restoration of alveolar-capillary barrier function alone may be of equal or even more benefit than improving AFC for ALI/ARDS treatment.
急性肺损伤/急性呼吸窘迫综合征（ALI/ARDS）的特征是弥漫性肺泡损伤和显著的水肿积聚，这与肺泡液体清除（AFC）受损和肺泡毛细血管屏障破坏有关，导致急性呼吸衰竭。我们之前的数据表明，电穿孔介导的 Na，K-ATPaseβ1 亚基基因转导不仅增加了 AFC，而且通过上调紧密连接蛋白恢复了肺泡屏障功能，从而导致小鼠脂多糖诱导的 ALI 得到治疗。更重要的是，我们最近的出版物表明，MRCKα（β1 亚基介导的信号通路的下游效应物，可上调黏附连接和上皮及内皮屏障完整性）的基因转导也为 ARDS 的体内治疗提供了治疗潜力，但不一定会加速 AFC，这表明对于 ARDS 的治疗，改善肺泡毛细血管屏障功能可能比改善液体清除更有益。在本研究中，我们研究了 Na，K-ATPase 的另外两个β同工型β2 和β3 亚基对 LPS 诱导的 ALI 的治疗潜力。我们发现，与未受伤动物的基础水平相比，β1、β2 或β3 亚基的基因转导均显著增加了 AFC，并且彼此之间的 AFC 增加也相似。然而，与β1 亚基不同的是，β2 或β3 亚基的基因转导到受损动物的肺部并没有显示出减轻组织学损伤、中性粒细胞浸润、整体肺水肿或增加肺通透性的有益作用，这表明β2 或β3 基因转导不能治疗 LPS 诱导的肺损伤。此外，虽然β1 基因转导增加了损伤小鼠肺部关键紧密连接蛋白的水平，但β2 或β3 亚基的基因转导对紧密连接蛋白的水平没有影响。综上所述，这强烈表明，恢复肺泡毛细血管屏障功能对于 ALI/ARDS 的治疗可能与改善 AFC 同等重要，甚至更有益。
