Department of Anesthesiology and Perioperative Medicine, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35295, USA; Division of Molecular and Translational Biomedicine, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35295, USA; Pulmonary Injury and Repair Center, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35295, USA; Gregory Fleming James Cystic Fibrosis Research Center, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35295, USA.
Department of Anesthesiology and Perioperative Medicine, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35295, USA; Division of Molecular and Translational Biomedicine, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35295, USA.
Matrix Biol. 2023 Feb;116:67-84. doi: 10.1016/j.matbio.2023.02.002. Epub 2023 Feb 8.
Herein, we tested the hypothesis that low molecular weight hyaluronan (LMW-HA) inhibits lung epithelial ions transport in-vivo, ex-vivo, and in-vitro by activating the calcium-sensing receptor (CaSR). Twenty-four hours post intranasal instillation of 50-150 µg/ml LMW-HA to C57BL/6 mice, there was a 75% inhibition of alveolar fluid clearance (AFC), a threefold increase in the epithelial lining fluid (ELF) depth, and a 20% increase in lung wet/dry (W/D) ratio. Incubation of human and mouse precision cut lung slices with 150 µg/ml LMW-HA reduced the activity and the open probability (P) of epithelial sodium channel (ENaC) in alveolar epithelial type 2 (ATII) cells, and in mouse tracheal epithelial cells (MTEC) monolayers as early as 4 h. The Cl current through cystic fibrosis transmembrane conductance regulator (CFTR) and the activity of Na,K-ATPase were both inhibited by more than 66% at 24 h. The inhibitory effects of LMW-HA on ion channels were reversed by 1 µM NPS-2143, or 150 µg/ml high molecular weight hyaluronan (HMW-HA). In HEK-293 cells expressing the calcium-sensitive Cl channel TMEM16-A, CaSR was required for the activation of the Cl current by LMW-HA. This is the first demonstration of lung ions and water transport inhibition by LMW-HA, and its mediation through the activation of CaSR.
在此，我们通过激活钙敏感受体（CaSR）来检验低相对分子质量透明质酸（LMW-HA）抑制肺上皮离子转运的假说，该假说涉及体内、体外和离体实验。在给 C57BL/6 小鼠鼻腔内滴注 50-150μg/ml 的 LMW-HA 24 小时后，肺泡液清除率（AFC）下降 75%，上皮衬液（ELF）深度增加三倍，肺湿重/干重（W/D）比值增加 20%。将 150μg/ml 的 LMW-HA 与人类和小鼠的精密切割肺切片孵育，最早在 4 小时时，肺泡上皮细胞 2 型（ATII）和小鼠气管上皮细胞（MTEC）单层中上皮钠通道（ENaC）的活性和开放概率（P）就降低了 3 倍。LMW-HA 对囊性纤维化跨膜电导调节因子（CFTR）的 Cl 电流和 Na,K-ATPase 的活性的抑制作用在 24 小时时超过了 66%。LMW-HA 对离子通道的抑制作用可以被 1μM NPS-2143 或 150μg/ml 高分子量透明质酸（HMW-HA）逆转。在表达钙敏感受体 Cl 通道 TMEM16-A 的 HEK-293 细胞中，CaSR 是 LMW-HA 激活 Cl 电流所必需的。这是首次证明 LMW-HA 抑制肺离子和水转运及其通过激活 CaSR 进行介导。
