Anton Friederike, Leverkoehne Ina, Mundhenk Lars, Thoreson Wallace B, Gruber Achim D
Department of Pathology, School of Veterinary Medicine Hannover, Hannover, Germany.
J Histochem Cytochem. 2005 Aug;53(8):1011-21. doi: 10.1369/jhc.4A6599.2005. Epub 2005 May 6.
The human hCLCA1 and murine mCLCA3 (chloride channels, calcium-activated) have recently been identified as promising therapeutic targets in asthma. Recurrent airway obstruction in horses is an important animal model of human asthma. Here, we have cloned and characterized the first equine CLCA family member, eCLCA1. The 913 amino acids eCLCA1 polypeptide forms a 120-kDa transmembrane glycoprotein that is processed to an 80-kDa protein in vivo. Three single nucleotide polymorphisms were detected in the eCLCA1 coding region in 14 horses, resulting in two amino acid changes (485H/R and 490V/L). However, no functional differences were recorded between the channel properties of the two variants in transfected HEK293 cells. The eCLCA1 protein was detected immunohistochemically in mucin-producing cells in the respiratory and intestinal tracts, cutaneous sweat glands, and renal mucous glands. Strong overexpression of eCLCA1 was observed in the airways of horses with recurrent airway obstruction using Northern blot hybridization, Western blotting, immunohistochemistry, and real-time quantitative RT-PCR. The results suggest that spontaneous or experimental recurrent airway obstruction in horses may serve as a model to study the role of CLCA homologs in chronic airway disease with overproduction of mucins.
人源hCLCA1和鼠源mCLCA3（钙激活氯离子通道）最近被确定为哮喘治疗的潜在靶点。马的复发性气道阻塞是人类哮喘的一种重要动物模型。在此，我们克隆并鉴定了首个马源CLCA家族成员eCLCA1。由913个氨基酸组成的eCLCA1多肽形成一个120 kDa的跨膜糖蛋白，在体内可加工成一个80 kDa的蛋白。在14匹马的eCLCA1编码区检测到三个单核苷酸多态性，导致两个氨基酸变化（485H/R和490V/L）。然而，在转染的HEK293细胞中，这两种变体的通道特性未记录到功能差异。通过免疫组织化学方法在呼吸道和肠道的黏蛋白分泌细胞、皮肤汗腺和肾黏液腺中检测到eCLCA1蛋白。使用Northern印迹杂交、蛋白质免疫印迹、免疫组织化学和实时定量RT-PCR方法，在患有复发性气道阻塞的马的气道中观察到eCLCA1的强烈过表达。结果表明，马的自发性或实验性复发性气道阻塞可作为研究CLCA同源物在黏蛋白过度产生的慢性气道疾病中作用的模型。
