Dominant role of interstitial cells of Cajal in nitrergic relaxation of murine lower oesophageal sphincter
Dominant role of interstitial cells of Cajal in nitrergic relaxation of murine lower oesophageal sphincter
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DOI：
10.1113/jphysiol.2014.273540
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发表时间：
2015-01-15
影响因子：
5.5
通讯作者：
Friebe, Andreas
中科院分区：
文献类型：
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作者：
Groneberg, Dieter;Zizer, Eugen;Friebe, Andreas
食管失弛缓症是一种已知由食管下括约肌（LES）松弛减少引起的疾病。一氧化氮（NO）是主要的抑制性递质之一。NO敏感鸟苷酸环化酶（NO-GC）作为NO的关键靶点，通过产生cGMP介导LES中的氮能松弛。迄今为止，氮能LES松弛的确切机制仍不充分阐明。为了阐明NO-GC在LES松弛中的作用，我们使用细胞特异性敲除（KO）小鼠系用于NO-GC。这些包括在平滑肌细胞（SMC-GCKO）、Cajal间质细胞（ICC-GCKO）和SMC/ICC（SMC/ICC-GCKO）中缺乏NO-GC的小鼠。我们应用食管测压研究LES在体内的功能。采用离体等长收缩法检测LES对外源性NO和电场刺激内源性神经的反应性。通过免疫组织化学监测NO-GC的细胞特异性表达/缺失。通过在ICC中删除NO-GC，吞咽诱导的LES松弛强烈降低。基础LES张力受SMC或ICC中NO-GC缺失的影响。两种细胞中NO-GC的缺乏导致NO诱导的松弛的完全中断，因此，导致与全球GCKO小鼠中所见相似的失弛缓症样表型。我们的数据表明，基础LES张力的调节是基于双重机制介导的NO-GC在SMC和ICC，而吞咽诱导的LES松弛主要是由氮能机制在ICC调节。
Oesophageal achalasia is a disease known to result from reduced relaxation of the lower oesophageal sphincter (LES). Nitric oxide (NO) is one of the main inhibitory transmitters. NO-sensitive guanylyl cyclase (NO-GC) acts as the key target of NO and, by the generation of cGMP, mediates nitrergic relaxation in the LES. To date, the exact mechanism of nitrergic LES relaxation is still insufficiently elucidated. To clarify the role of NO-GC in LES relaxation, we used cell-specific knockout (KO) mouse lines for NO-GC. These include mice lacking NO-GC in smooth muscle cells (SMC-GCKO), in interstitial cells of Cajal (ICC-GCKO) and in both SMC/ICC (SMC/ICC-GCKO). We applied oesophageal manometry to study the functionality of LES in vivo. Isometric force studies were performed to monitor LES responsiveness to exogenous NO and electric field stimulation of intrinsic nerves in vitro. Cell-specific expression/deletion of NO-GC was monitored by immunohistochemistry. Swallowing-induced LES relaxation is strongly reduced by deletion of NO-GC in ICC. Basal LES tone is affected by NO-GC deletion in either SMC or ICC. Lack of NO-GC in both cells leads to a complete interruption of NO-induced relaxation and, therefore, to an achalasia-like phenotype similar to that seen in global GCKO mice. Our data indicate that regulation of basal LES tone is based on a dual mechanism mediated by NO-GC in SMC and ICC whereas swallow-induced LES relaxation is mainly regulated by nitrergic mechanisms in ICC.