Jackson S R, Costa M F D M, Pastore C F, Zhao G, Weiner A I, Adams S, Palashikar G, Quansah K, Hankenson K, Herbert D R, Vaughan A E
Department of Biomedical Sciences, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce St., Old Vet 372E, Philadelphia, PA, 19104, USA.
Department of Orthopaedic Surgery, University of Michigan School of Medicine, Ann Arbor, MI, 48109, USA.
BMC Res Notes. 2020 Feb 4;13(1):54. doi: 10.1186/s13104-020-4930-8.
R-spondin 2 (RSPO2) is required for lung morphogenesis, activates Wnt signaling, and is upregulated in idiopathic lung fibrosis. Our objective was to investigate whether RSPO2 is similarly important in homeostasis of the adult lung. While investigating the characteristics of bronchoalveolar lavage in RSPO2-deficient (RSPO2) mice, we observed unexpected changes in neutrophil homeostasis and vascular permeability when compared to control (RSPO2) mice at baseline. Here we quantify these observations to explore how tonic RSPO2 expression impacts lung homeostasis.
Quantitative PCR (qPCR) analysis demonstrated significantly elevated myeloperoxidase (MPO) expression in bronchoalveolar lavage fluid (BALF) cells from RSPO2 mice. Likewise, immunocytochemical (ICC) analysis demonstrated significantly more MPO+ cells in BALF from RSPO2 mice compared to controls, confirming the increase of infiltrated neutrophils. We then assessed lung permeability/barrier disruption via Fluorescein Isothiocyanate (FITC)-dextran instillation and found a significantly higher dextran concentration in the plasma of RSPO2 mice compared to identically treated RSPO2 mice. These data demonstrate that RSPO2 may be crucial for blood-gas barrier integrity and can limit neutrophil migration from circulation into alveolar spaces associated with increased lung permeability and/or barrier disruption. This study indicates that additional research is needed to evaluate RSPO2 in scenarios characterized by pulmonary edema or neutrophilia.
R-spondin 2（RSPO2）是肺形态发生所必需的，可激活Wnt信号通路，且在特发性肺纤维化中上调。我们的目的是研究RSPO2在成年肺稳态中是否同样重要。在研究RSPO2基因缺陷（RSPO2-/-）小鼠的支气管肺泡灌洗特征时，我们观察到与基线时的对照（RSPO2+/+）小鼠相比，中性粒细胞稳态和血管通透性出现了意外变化。在此，我们对这些观察结果进行量化，以探讨持续的RSPO2表达如何影响肺稳态。
定量聚合酶链反应（qPCR）分析表明，RSPO2-/-小鼠支气管肺泡灌洗液（BALF）细胞中的髓过氧化物酶（MPO）表达显著升高。同样，免疫细胞化学（ICC）分析表明，与对照组相比，RSPO2-/-小鼠BALF中的MPO+细胞明显更多，证实了浸润中性粒细胞的增加。然后，我们通过异硫氰酸荧光素（FITC）-葡聚糖灌注评估肺通透性/屏障破坏情况，发现与相同处理的RSPO2+/+小鼠相比，RSPO2-/-小鼠血浆中的葡聚糖浓度显著更高。这些数据表明，RSPO2可能对血气屏障完整性至关重要，并可限制中性粒细胞从循环系统迁移到与肺通透性增加和/或屏障破坏相关的肺泡空间。这项研究表明，需要进一步研究以评估在肺水肿或中性粒细胞增多的情况下的RSPO2。
