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首页> 外文学位 >Contribution a l'etude du mecanisme de secretion d'ATP par des cellules epitheliales pulmonaires et des fibroblastes soumis a un choc hypotonique.
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Contribution a l'etude du mecanisme de secretion d'ATP par des cellules epitheliales pulmonaires et des fibroblastes soumis a un choc hypotonique.

机译：对低渗性休克的肺上皮细胞和成纤维细胞ATP分泌机制研究的贡献。

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摘要

Hypotonic shock releases ATP from a variety of cells by a poorly defined mechanism(s). The suggestion that extracellular ATP might be involved in mucociliary clearance and alveoli fluid secretion prompted many studies aimed at discovering the nature of the ATP release pathway in lung and elsewhere. A mechano-sensitive ATP channel has been implicated during the past five years because Gd 3+, an inhibitor of stretch-activated channels, suppressed cell swelling-induced ATP efflux monitored by luciferase bioluminescence. We found that concentrations typically used to block mechanosensitive channels, actually stimulated hypotonically-induced ATP release from fibroblasts (NIH/3T3) and inhibition of ATP release required dosages much higher for fibroblasts, lung epithelial A549 and 16HBE14o - cells. Such cell-specific effects of Gd3+ were most consistent with its action on membrane lipids and membrane-dependent processes such as exocytosis. To further investigate this preliminary finding, we evaluated for those previous cells, the kinetics of cell swelling-induced ATP secretion and intracellular calcium changes. The concomitant volume changes of substrate-attached cells were also analyzed with a three-dimensional cell shape reconstruction method based on images acquired from 2-perpendicular directions with the use of a custom-designed flow-through chamber. These experiments revealed, that cell swelling-induced ATP release neither correlate with cell volume expansion and the expected activation of stretch-sensitive channels, nor with the activation of volume-sensitive, NPPB-inhibitable anion channels during RVD. By contrast, ATP release was synchronized, in all three cell types, with cytosolic calcium elevations. Furthermore, a calcium ionophore triggered ATP release in the absence of cell swelling, while it was significantly diminished by loading cells with a calcium chelator or by lowering the temperature to 10°C. These results strongly support the involvement of a calcium-dependent exocytosis in cell swelling-induced ATP release.
机译：低渗性休克通过定义不清的机制从多种细胞释放ATP。细胞外ATP可能参与粘液纤毛清除和肺泡液分泌的建议促使许多研究旨在发现肺和其他地方ATP释放途径的性质。在过去的五年中，牵涉到机械敏感的ATP通道，因为拉伸激活通道的抑制剂Gd 3+抑制了通过荧光素酶生物发光监测的细胞肿胀诱导的ATP外排。我们发现通常用于阻断机械敏感性通道的浓度，实际上刺激了低渗诱导的从成纤维细胞（NIH / 3T3）释放的ATP，并且抑制ATP释放对于成纤维细胞，肺上皮A549和16HBE140细胞的剂量要高得多。 Gd3 +的这种细胞特异性作用与它对膜脂质和膜依赖性过程（如胞吐作用）的作用最一致。为了进一步研究这一初步发现，我们对先前的那些细胞进行了评估，这些动力学是细胞膨胀诱导的ATP分泌和细胞内钙变化的动力学。还使用三维细胞形状重建方法，基于从2个垂直方向获取的图像，并使用定制设计的流通室，分析了与基质附着细胞的伴随体积变化。这些实验表明，细胞膨胀诱导的ATP释放既不与细胞体积膨胀和预期的舒张敏感通道激活相关，也不与RVD期间对体积敏感的NPPB抑制性阴离子通道的激活相关。相反，在所有三种细胞类型中，ATP释放与胞质钙升高同步。此外，钙离子载体在没有细胞膨胀的情况下触发了ATP的释放，而通过向细胞中加入钙螯合剂或将温度降低至10°C可以显着降低ATP的释放。这些结果强烈支持钙依赖性胞吐作用参与细胞膨胀诱导的ATP释放。

著录项

  • 作者

    Boudreault, Francis.;

  • 作者单位

    Universite de Montreal (Canada).;

  • 授予单位 Universite de Montreal (Canada).;
  • 学科 Biology Animal Physiology.
  • 学位 Ph.D.
  • 年度 2005
  • 页码 113 p.
  • 总页数 113
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 生理学;
  • 关键词

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