Tomuschat Christian, O'Donnell Anne Marie, Coyle David, Puri Prem
National Children's Research Centre, Our Lady's Children's Hospital, Crumlin, Dublin 12, Ireland.
Conway Institute of Biomedical Research, School of Medicine and Medical Science, University College Dublin, Dublin, Ireland.
Pediatr Surg Int. 2016 Jan;32(1):9-16. doi: 10.1007/s00383-015-3807-8. Epub 2015 Oct 30.
The pathophysiology of Hirschsprung's disease (HSCR) is not entirely understood. There is no clear explanation for the occurrence of the spastic or tonically contracted aganglionic segment of bowel. Kv11.1 (hERG) channels play a critical role in the regulation of the resting membrane potential as well as affecting either the force or frequency of contraction of smooth muscles. We designed this study to investigate the expression and distribution of hERG channels in the normal colon and the colon of patients with HSCR.
We investigated hERG protein expression in both the ganglionic and aganglionic regions of HSCR patients (n = 10) versus normal control colon (n = 10). Protein distribution was assessed using immunofluorescence and confocal microscopy. Gene and protein expressions were quantified using real-time polymerase chain reaction, western blot analysis and densitometry.
Confocal microscopy of the normal colon revealed strong hERG channel expression in interstitial cells of Cajal, platelet-derived growth factor-alpha receptor- (PDGFRα(+)) positive cells and enteric neurons. hERG expression was markedly decreased in aganglionic bowel, whereas colonic hERG gene expression levels were significantly decreased in aganglionic compared to ganglionic bowel and controls (p < 0.05). Western blotting revealed decreased colonic hERG protein expression in aganglionic HSCR specimens compared to controls.
We demonstrate, for the first time, the expression and distribution of hERG channels in the human colon. The decreased expression of hERG in the aganglionic colon may be responsible for the increased tone in the aganglionic narrow spastic segment of bowel.
先天性巨结肠（HSCR）的病理生理学尚未完全明确。对于肠道痉挛或强直性收缩的无神经节段的发生，目前尚无明确解释。Kv11.1（hERG）通道在静息膜电位的调节中起关键作用，同时也影响平滑肌的收缩力或频率。我们设计本研究旨在调查hERG通道在正常结肠及HSCR患者结肠中的表达和分布情况。
我们研究了HSCR患者（n = 10）与正常对照结肠（n = 10）的神经节段和无神经节段中hERG蛋白的表达。使用免疫荧光和共聚焦显微镜评估蛋白分布。通过实时聚合酶链反应、蛋白质印迹分析和光密度测定法定量基因和蛋白表达。
正常结肠的共聚焦显微镜检查显示，Cajal间质细胞、血小板衍生生长因子-α受体（PDGFRα(+)）阳性细胞和肠神经元中hERG通道表达强烈。无神经节肠段中hERG表达明显降低，而与神经节肠段和对照组相比，无神经节结肠的hERG基因表达水平显著降低（p < 0.05）。蛋白质印迹分析显示，与对照组相比，无神经节HSCR标本中结肠hERG蛋白表达降低。
我们首次证明了hERG通道在人类结肠中的表达和分布。无神经节结肠中hERG表达降低可能是导致无神经节狭窄痉挛段肠道张力增加的原因。
