Akaike Norio, Ito Yushi, Ogawa Sachie K, Maeda Megumi, Wakita Masahito, Takahama Kazuo, Noguchi Tetsuro, Kamei Shintaro, Hamamoto Takayoshi, Umehashi Misako, Maeda Hiroaki
Research Division for Life Science, Kumamoto Health Science University, 325 Izumi-machi, Kita-ku, Kumamoto 861-5598, Japan.
Gen Physiol Biophys. 2014;33(2):145-55. doi: 10.4149/gpb_2013083. Epub 2014 Jan 22.
Human plasma contains wide variety of bioactive proteins that have proved essential in therapeutic discovery. However many human plasma proteins remain orphans with unknown biological functions. Evidences suggest that some plasma components target the respiratory system. In the present study we adapted heparin affinity chromatography to fractionate human plasma for functional bioassay. Fractions from pooled human plasma yielded particular plasma fractions with strong cough suppressing effects. Purification yielded a fraction that was finally identified as an activated blood coagulation factor fXIa using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and matrix-assisted laser desorption ionization/time-of-flight mass spectrometry (MALDI/TOF-MS). The fraction almost completely suppressed coughs induced by either chemical or mechanical stimulation applied to larynx or bifurcation of guinea-pig trachea. Cough suppressing effect of the fraction and commercially available fXIa were one million times stronger than codeine and codeine only partially suppressed the mechanically triggered coughing in animal model. Recent reviews highlighted prominent shortcomings of current available antitussives, including narcotic opioids such as codeine and their unpleasant or intolerable side effects. Therefore, safer and more effective cough suppressants would be welcome, and present findings indicate that fXIa in human plasma as a very promising, new therapeutic candidate for effective antitussive action.
人血浆中含有多种生物活性蛋白，这些蛋白已被证明在治疗药物研发中至关重要。然而，许多人血浆蛋白仍然是功能未知的孤儿蛋白。有证据表明，一些血浆成分作用于呼吸系统。在本研究中，我们采用肝素亲和层析法对人血浆进行分离，以进行功能生物测定。来自混合人血浆的组分产生了具有强烈镇咳作用的特定血浆组分。通过液相色谱-串联质谱（LC-MS/MS）和基质辅助激光解吸电离/飞行时间质谱（MALDI/TOF-MS）对纯化后的组分进行鉴定，最终确定其为活化的血液凝固因子fXIa。该组分几乎完全抑制了对豚鼠喉部或气管分叉处施加化学或机械刺激所诱发的咳嗽。该组分和市售fXIa的镇咳效果比可待因强一百万倍，且可待因在动物模型中仅能部分抑制机械触发的咳嗽。最近的综述强调了目前可用镇咳药的突出缺点，包括可待因等麻醉性阿片类药物及其令人不适或难以忍受的副作用。因此，更安全、更有效的镇咳药将受到欢迎，目前的研究结果表明，人血浆中的fXIa是一种非常有前景的新型有效镇咳治疗候选药物。
