Muc5b and Muc5ac are the major oligomeric mucins in equine airway mucus
Muc5b and Muc5ac are the major oligomeric mucins in equine airway mucus
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DOI：
10.1152/ajplung.00444.2006
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发表时间：
2007-06-01
影响因子：
4.9
通讯作者：
Thornton, David J.
中科院分区：
文献类型：
--
作者：
Rousseau, Karine;Kirkham, Sara;Thornton, David J.
马经常患有呼吸道疾病，无论病因如何，通常与气道粘液积聚有关。对人类气道的研究表明，粘液层的关键结构组分是寡聚粘蛋白，其在疾病中可以经历表达和性质的变化。然而，关于马气道粘液中这些凝胶形成糖蛋白的信息很少。因此，本研究的目的是分离马气道寡聚粘蛋白，表征其大分子特性，并确定其基因产物。为此，用6 M氯化胍（GdmCl）溶解从健康马和患有呼吸道疾病的马收集的合并气管洗液。通过密度梯度离心，然后通过尺寸排阻色谱法纯化寡聚粘蛋白。生物化学和生物物理学分析显示，粘蛋白在溶液中是刚性无规卷曲，其大小是多分散的（M-r = 6 - 20 MDa，平均M-r = 14 MDa），并且由二硫键连接的亚基（平均M-r = 7 MDa）组成。琼脂糖凝胶电泳显示，合并的粘液样品含有至少两个群体的低聚粘蛋白。未分级粘蛋白制剂的胰蛋白酶解物的电喷雾电离串联质谱显示存在寡聚粘蛋白Muc 5 b和Muc 5ac。总之，我们已经表明马气道粘液是Muc 5 b和Muc 5ac粘蛋白的混合物，其具有与其人类对应物相似的大分子组织。这项研究将为未来的研究奠定基础，以分析这两种粘蛋白对与粘液积聚相关的马气道病理学的贡献。
Horses frequently suffer from respiratory diseases, which, irrespective of etiology, are often associated with airway mucus accumulation. Studies on human airways have shown that the key structural components of the mucus layer are oligomeric mucins, which can undergo changes of expression and properties in disease. However, there is little information on these gel- forming glycoproteins in horse airways mucus. Therefore, the aims of this study were to isolate equine airways oligomeric mucins, characterize their macromolecular properties, and identify their gene products. To this end, pooled tracheal washes, collected from healthy horses and horses suffering from respiratory diseases, were solubilized with 6 M guanidinium chloride ( GdmCl). The oligomeric mucins were purified by density gradient centrifugation followed by size exclusion chromatography. Biochemical and biophysical analyses showed the mucins were stiffened random coils in solution that were polydisperse in size ( M-r = 6 - 20 MDa, average M-r = 14 MDa) and comprised of disulfide- linked subunits ( average M-r = 7 MDa). Agarose gel electrophoresis showed that the pooled mucus sample contained at least two populations of oligomeric mucins. Electrospray ionization tandem mass spectrometry of tryptic digests of the unfractionated mucin preparation showed that the oligomeric mucins Muc5b and Muc5ac were present. In summary, we have shown that equine airways mucus is a mixture of Muc5b and Muc5ac mucins that have a similar macromolecular organization to their human counterparts. This study will form the basis for future studies to analyze the contribution of these two mucins to equine airways pathology associated with mucus accumulation.