Function of the HVCN1 proton channel in airway epithelia and a naturally occurring mutation, M91T.
Function of the HVCN1 proton channel in airway epithelia and a naturally occurring mutation, M91T.
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DOI：
10.1085/jgp.200910379
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发表时间：
2010-07
期刊：
影响因子：
--
通讯作者：
Fischer H
中科院分区：
文献类型：
--
作者：
Iovannisci D;Illek B;Fischer H
航空公司会分泌相当数量的酸。在这项研究中，我们研究了气道上皮细胞顶端H+通道的特性和pH依赖的功能。在Ussing小室汇合的JME气道上皮细胞的pH静态记录中，锌敏感酸的分泌在粘膜阈值pH为∼7时被激活，超过该阈值后，锌敏感酸的分泌以每pH单位339±34nmo1×h−1×cm−2的速率呈pH依赖性增加。同样，在膜片钳记录中测得的JME细胞的H+电流很容易被锌阻断，并被pH外的碱性物质激活。小干扰RNA抑制JME细胞中HVCN1mRNA的表达导致膜片钳记录中H+电流的丢失。从原代培养的人呼吸道上皮细胞中克隆出HVCN1的开放阅读框，得到了一个野生型克隆和一个具有两个碱基交换序列(452T>；C和453G>；A)的克隆，从而产生了一个新的错义突变M91T HVCN1。在检测的95个人类基因组DNA样本中，我们发现了一个M91T突变杂合子的HVCN1等位基因。与野生型上皮细胞相比，自然表达M91T HVCN1的上皮细胞要激活酸分泌，需要∼0.5pH单位以上的碱性粘膜pH值。同样，与野生型HVCN1相比，跨重组表达的M91T HVCN1激活H+电流需要显著更大的pH梯度。这项研究提供了功能和分子方面的迹象，即HVCN1 H+通道介导了气道上皮细胞pH调节的酸分泌。这些数据表明，顶端的HVCN1代表了一种使碱性呼吸道表面液体酸化的机制。
Airways secrete considerable amounts of acid. In this study, we investigated the identity and the pH-dependent function of the apical H+ channel in the airway epithelium. In pH stat recordings of confluent JME airway epithelia in Ussing chambers, Zn-sensitive acid secretion was activated at a mucosal threshold pH of ∼7, above which it increased pH-dependently at a rate of 339 ± 34 nmol × h−1 × cm−2 per pH unit. Similarly, H+ currents measured in JME cells in patch clamp recordings were readily blocked by Zn and activated by an alkaline outside pH. Small interfering RNA–mediated knockdown of HVCN1 mRNA expression in JME cells resulted in a loss of H+ currents in patch clamp recordings. Cloning of the open reading frame of HVCN1 from primary human airway epithelia resulted in a wild-type clone and a clone characterized by two sequential base exchanges (452T>C and 453G>A) resulting in a novel missense mutation, M91T HVCN1. Out of 95 human genomic DNA samples that were tested, we found one HVCN1 allele that was heterozygous for the M91T mutation. The activation of acid secretion in epithelia that natively expressed M91T HVCN1 required ∼0.5 pH units more alkaline mucosal pH values compared with wild-type epithelia. Similarly, activation of H+ currents across recombinantly expressed M91T HVCN1 required significantly larger pH gradients compared with wild-type HVCN1. This study provides both functional and molecular indications that the HVCN1 H+ channel mediates pH-regulated acid secretion by the airway epithelium. These data indicate that apical HVCN1 represents a mechanism to acidify an alkaline airway surface liquid.
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影响因子：
--
作者：
JEFFERSON, DM;VALENTICH, JD;WELSH, MJ
通讯作者：
WELSH, MJ
影响因子：
3.3
作者：
KYLE, H;WARD, JPT;WIDDICOMBE, JG
通讯作者：
WIDDICOMBE, JG
影响因子：
2.6
作者：
Cho DY;Hajighasemi M;Hwang PH;Illek B;Fischer H
通讯作者：
Fischer H
影响因子：
15.9
作者：
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通讯作者：
Verkman, AS
影响因子：
4.8
作者：
Musset, Boris;Capasso, Melania;DeCoursey, Thomas E.
通讯作者：
DeCoursey, Thomas E.