没有证据表明哮喘患者气道平滑肌细胞的细胞内钙处理存在改变。
No evidence for altered intracellular calcium-handling in airway smooth muscle cells from human subjects with asthma.
作者信息
Sweeney David, Hollins Fay, Gomez Edith, Mistry Rajendra, Saunders Ruth, Challiss Robert Alfred John, Brightling Christopher Edward
机构信息
Department of Infection, Immunity & Inflammation, and Institute for Lung Health, University of Leicester, Glenfield Hospital, Leicester, LE3 9QP, UK.
Department of Cell Physiology & Pharmacology, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester, LE1 9HN, UK.
出版信息
BMC Pulm Med. 2015 Feb 13;15:12. doi: 10.1186/s12890-015-0009-z.
BACKGROUND
Asthma is characterized by airway hyper-responsiveness and variable airflow obstruction, in part as a consequence of hyper-contractile airway smooth muscle, which persists in primary cell culture. One potential mechanism for this hyper-contractility is abnormal intracellular Ca(2+) handling.
METHODS
We sought to compare intracellular Ca(2+) handling in airway smooth muscle cells from subjects with asthma compared to non-asthmatic controls by measuring: i) bradykinin-stimulated changes in inositol 1,4,5-trisphosphate (IP3) accumulation and intracellular Ca(2+) concentration, ii) sarco/endoplasmic reticulum Ca(2+)-ATPase (SERCA) expression, iii) mechanisms of cytoplasmic Ca(2+) clearance assessed following instantaneous flash photolytic release of Ca(2+) into the cytoplasm.
RESULTS
We found no differences in airway smooth muscle cell basal intracellular Ca(2+) concentrations, bradykinin-stimulated IP3 accumulation or intracellular Ca(2+) responses. Quantification of SERCA2 mRNA or protein expression levels revealed no differences in ASM cells obtained from subjects with asthma compared to non-asthmatic controls. We did not identify differences in intracellular calcium kinetics assessed by flash photolysis and calcium uncaging independent of agonist-activation with or without SERCA inhibition. However, we did observe some correlations in subjects with asthma between lung function and the different cellular measurements of intracellular Ca(2+) handling, with poorer lung function related to increased rate of recovery following flash photolytic elevation of cytoplasmic Ca(2+) concentration.
CONCLUSIONS
Taken together, the experimental results reported in this study do not demonstrate major fundamental differences in Ca(2+) handling between airway smooth muscle cells from non-asthmatic and asthmatic subjects. Therefore, increased contraction of airway smooth muscle cells derived from asthmatic subjects cannot be fully explained by altered Ca(2+) homeostasis.
背景
哮喘的特征为气道高反应性和可变气流受限，部分原因是气道平滑肌过度收缩，这种情况在原代细胞培养中持续存在。这种过度收缩的一个潜在机制是细胞内钙离子（Ca(2+)）处理异常。
方法
我们试图通过测量以下指标，比较哮喘患者与非哮喘对照者气道平滑肌细胞内的钙离子处理情况：i）缓激肽刺激后肌醇1,4,5-三磷酸（IP3）积累和细胞内钙离子浓度的变化；ii）肌浆网/内质网Ca(2+)-ATP酶（SERCA）的表达；iii）在向细胞质中瞬时闪光光解释放Ca(2+)后评估细胞质Ca(2+)清除的机制。
结果
我们发现气道平滑肌细胞的基础细胞内钙离子浓度、缓激肽刺激后的IP3积累或细胞内钙离子反应没有差异。对SERCA2 mRNA或蛋白质表达水平的定量分析显示，与非哮喘对照者相比，哮喘患者的气道平滑肌细胞没有差异。我们没有发现通过闪光光解和钙离子解笼法评估的细胞内钙动力学存在差异，这与有无SERCA抑制的激动剂激活无关。然而，我们确实观察到哮喘患者的肺功能与细胞内钙离子处理的不同细胞测量值之间存在一些相关性，肺功能较差与闪光光解提高细胞质钙离子浓度后的恢复速率增加有关。
结论
综上所述，本研究报告的实验结果并未表明非哮喘和哮喘患者气道平滑肌细胞在钙离子处理方面存在重大的根本差异。因此，哮喘患者气道平滑肌细胞收缩增加不能完全用钙离子稳态改变来解释。
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