School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong.
J Ethnopharmacol. 2011 Oct 31;138(1):201-11. doi: 10.1016/j.jep.2011.08.081. Epub 2011 Sep 12.
The caterpillar fungus Cordyceps militaris (CM; Clavicipitaceae) is a well-known traditional Chinese medicine that can be artificially cultivated on a large scale. We have previously demonstrated that its stimulatory action on ion transport in human airway epithelia is similar to Cordyceps sinensis (Clavicipitaceae), which has been traditionally used to treat respiratory diseases.
To investigate the signal transduction mechanism(s) underlying CM-induced ion transport activity in cultured human bronchial epithelia.
16HBE14o-, a human bronchial epithelial cell line, was used to study the regulation of ion transport by the water extract of CM. CM extract was added to the apical or basolateral aspect of the epithelia. In subsequent experiments, different Cl(-) channel and K(+) channel blockers, adenylate cyclase and protein kinase A (PKA) inhibitors, and an intracellular Ca(2+) chelator were used to examine the involvement of apical Cl(-) and basolateral K(+) channels in mediating CM-induced Cl(-) secretion and the underlying signal transduction mechanism(s). PKA activity was also measured in 16HBE14o- cells.
CM stimulated Cl(-) secretion across 16HBE14o- monolayers in a dose-dependent manner. Cl(-) secretion could be inhibited by apical application of the cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-)channel blocker and the calcium-activated Cl(-) channel (CaCC) blocker. Cl(-) secretion was sensitive to basolateral application of different K(+) channel blockers. Similar inhibitory patterns were obtained in nystatin-permeabilized epithelia. The CM-induced Cl(-) secretion could be inhibited by adenylate cyclase and PKA inhibitors as well as an intracellular Ca(2+) chelator. Data from the PKA assay suggested that CM extract caused a significant increase in PKA activity compared with untreated control epithelia.
These results suggest that CM extract stimulated Cl(-) secretion across human bronchial epithelia, possibly via apical CFTR and CaCC, and the basolateral K(+) channels are involved in driving apical Cl(-) exit. The underlying signal transduction mechanisms involve both cAMP- and Ca(2+)-dependent pathways.
蛹虫草（CM；虫草科）是一种广为人知的传统中药，可大规模人工栽培。我们之前已经证明，其对人呼吸道上皮细胞离子转运的刺激作用类似于蛹虫草（Clavicipitaceae），后者传统上用于治疗呼吸道疾病。
研究 CM 诱导的离子转运活性在培养的人支气管上皮细胞中的信号转导机制。
使用人支气管上皮细胞系 16HBE14o-研究 CM 水提取物对离子转运的调节。CM 提取物被添加到上皮的顶端或基底外侧。在后续实验中，使用不同的 Cl(-)通道和 K(+)通道阻滞剂、腺苷酸环化酶和蛋白激酶 A (PKA)抑制剂以及细胞内 Ca(2+)螯合剂，研究顶端 Cl(-)和基底外侧 K(+)通道在介导 CM 诱导的 Cl(-)分泌中的作用以及潜在的信号转导机制。还测量了 16HBE14o-细胞中的 PKA 活性。
CM 以剂量依赖性方式刺激 16HBE14o-单层细胞中的 Cl(-)分泌。顶端应用囊性纤维化跨膜电导调节剂 (CFTR) Cl(-)通道阻滞剂和钙激活 Cl(-)通道 (CaCC) 阻滞剂可抑制 Cl(-)分泌。Cl(-)分泌对基底外侧应用不同的 K(+)通道阻滞剂敏感。在制霉菌素通透的上皮中获得了类似的抑制模式。CM 诱导的 Cl(-)分泌可被腺苷酸环化酶和 PKA 抑制剂以及细胞内 Ca(2+)螯合剂抑制。PKA 测定的数据表明，与未处理的对照上皮相比，CM 提取物引起 PKA 活性显著增加。
这些结果表明，CM 提取物刺激人支气管上皮细胞的 Cl(-)分泌，可能通过顶端 CFTR 和 CaCC，基底外侧的 K(+) 通道参与驱动顶端 Cl(-)外流。潜在的信号转导机制涉及 cAMP 和 Ca(2+)依赖性途径。
