Jacquot J, Merten M, Millot J M, Sébille S, Ménager M, Figarella C, Manfait M
INSERM U.314, Université de Reims, France.
Biochem Biophys Res Commun. 1995 Jul 17;212(2):307-16. doi: 10.1006/bbrc.1995.1971.
Measurements of the intracellular free calcium concentration [Ca2+]i in single cells of the human tracheal gland cell line MM 39 demonstrate dynamic changes in [Ca2+]i after their exposure to human neutrophil elastase (HNE). A heterogeneity in [Ca2+]i responses measured cell to cell in monolayer culture is evident: cells generate an initial [Ca2+]i peak rise with or without a delayed time (up to 180 sec) followed either by a rapid return to baseline, asynchronous oscillations or a sustained plateau phase. From basal concentration of 85 +/- 15 nM, HNE (1 microM) produces a [Ca2+]i increase of 91 +/- 66 nM in about 50% of responding cells. At lower concentrations of HNE (0.1 microM, 0.01 microM), the [Ca2+]i rise remains similar, but only 30-40% of the cells are responding. Pretreatment of cells with the recombinant elafin protein, a specific elastase inhibitor, reduces both the [Ca2+]i response to HNE and the number of responding cells. Electron microscopy observations reveal an increased number of secretory granules located beneath the cell plasma membrane after HNE treatment. These results suggest that intracellular [Ca2+]i changes may be associated to the HNE-induced exocytosis in human tracheal gland cells. These findings could have implications with regard to the pathogenesis of increased mucus secretion in human airway diseases.
对人气管腺细胞系MM 39的单细胞内游离钙浓度[Ca2+]i的测量表明，其暴露于人类中性粒细胞弹性蛋白酶（HNE）后，[Ca2+]i会发生动态变化。在单层培养中，逐个细胞测量的[Ca2+]i反应存在异质性：细胞会产生初始的[Ca2+]i峰值升高，有或没有延迟时间（长达180秒），随后要么迅速恢复到基线，要么出现异步振荡或持续的平台期。从85±15 nM的基础浓度开始，1 μM的HNE在约50%的反应细胞中使[Ca2+]i增加91±66 nM。在较低浓度的HNE（0.1 μM、0.01 μM）下，[Ca2+]i升高情况相似，但只有30 - 40%的细胞有反应。用重组弹性蛋白（一种特异性弹性蛋白酶抑制剂）对细胞进行预处理，可降低[Ca2+]i对HNE的反应以及反应细胞的数量。电子显微镜观察显示，HNE处理后位于细胞质膜下方的分泌颗粒数量增加。这些结果表明，细胞内[Ca2+]i变化可能与HNE诱导的人气管腺细胞胞吐作用有关。这些发现可能对人类气道疾病中黏液分泌增加的发病机制具有启示意义。
