O'Donnell Anne Marie, Coyle David, Puri Prem
Anne Marie O'Donnell, David Coyle, Prem Puri, National Children's Research Centre, Our Lady's Children's Hospital, Crumlin, Dublin 12, Ireland.
World J Gastroenterol. 2015 May 14;21(18):5635-40. doi: 10.3748/wjg.v21.i18.5635.
To determine if hyperpolarisation-activated nucleotide-gated (HCN) channels exist in human colon, and to investigate the expression of HCN channels in Hirschsprung's disease.
We investigated HCN1, HCN2, HCN3 and HCN4 protein expression in pull-through specimens from patients with Hirschsprung's disease (HSCR, n = 10) using the proximal-most ganglionic segment and distal-most aganglionic segment, as well as in healthy control specimens obtained at the time of sigmoid colostomy closure in children who had undergone anorectoplasty for imperforate anus (n = 10). Fluorescent immunohistochemistry was performed to assess protein distribution, which was then visualized using confocal microscopy.
No HCN1 channel expression was observed in any of the tissues studied. Both HCN2 and HCN4 proteins were found to be equally expressed in the aganglionic and ganglionic bowel in HSCR and controls. HCN3 channel expression was found to be markedly decreased in the aganglionic colon vs ganglionic colon and controls. HCN2-4 channels were seen to be expressed within neurons of the myenteric and submucosal plexus of the ganglionic bowel and normal controls, and also co-localised to interstitial cells of Cajal in all tissues studied.
We demonstrate HCN channel expression in human colon for the first time. Reduced HCN3 expression in aganglionic bowel suggests its potential role in HSCR pathophysiology.
确定超极化激活的核苷酸门控（HCN）通道是否存在于人类结肠中，并研究HCN通道在先天性巨结肠病中的表达情况。
我们使用先天性巨结肠病（HSCR，n = 10）患者拖出标本的最近端神经节段和最远端无神经节段，以及在因肛门闭锁接受肛门直肠成形术的儿童乙状结肠造口关闭时获取的健康对照标本（n = 10），研究HCN1、HCN2、HCN3和HCN4蛋白的表达。进行荧光免疫组织化学以评估蛋白分布，然后使用共聚焦显微镜进行可视化观察。
在所研究的任何组织中均未观察到HCN1通道表达。在HSCR和对照组中，发现HCN2和HCN4蛋白在无神经节段和有神经节段的肠中均有同等表达。与有神经节段的结肠和对照组相比，发现无神经节段结肠中HCN3通道表达明显降低。在有神经节段的肠和正常对照的肌间神经丛和黏膜下神经丛的神经元中可见HCN2 - 4通道表达，并且在所有研究组织中也与Cajal间质细胞共定位。
我们首次证明了HCN通道在人类结肠中的表达。无神经节段肠中HCN3表达降低提示其在HSCR病理生理学中的潜在作用。
