The human urothelium consists of multiple clonal units, each maintained by a stem cell
The human urothelium consists of multiple clonal units, each maintained by a stem cell
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DOI：
10.1002/path.2945
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发表时间：
2011-10-01
影响因子：
7.3
通讯作者：
Wright, Nicholas A.
中科院分区：
文献类型：
--
作者：
Gaisa, Nadine T.;Graham, Trevor A.;Wright, Nicholas A.
人们对人尿路上皮的克隆构筑知之甚少。尿路上皮干细胞很可能存在于基底上皮层内，然而，从单个干细胞进行谱系追踪作为一种显示尿路上皮干细胞存在的手段从未进行过。在这里，我们识别人膀胱粘膜中克隆相关的细胞区，以便可视化由单个创建者/干细胞维持的上皮场。对16例冷冻膀胱切除标本进行连续切片。用双色酶组织化学方法鉴定线粒体编码酶细胞色素c氧化酶(CCO)缺失的细胞斑块。为了证明这些斑块代表克隆增殖，分别对CCO熟练和缺乏CCO的小区域进行了激光显微切割，并对每个区域的整个线粒体基因组(MtDNA)进行了PCR扩增和测序，以识别mtDNA突变。对尿路上皮及邻近间充质的不同细胞层进行免疫组织化学染色。所有膀胱切除标本的正常尿路上皮均可见CCO缺陷性斑块。这些负性斑块的二维长度从2-3个细胞(约30微米)到4.7毫米不等。CCO缺陷斑块内的每个细胞区都含有一个相同的体细胞线粒体DNA突变，表明该斑块是一个克隆单位。斑块包含了尿路上皮中存在的所有成熟细胞分化阶段，表明存在干细胞。我们的结果表明，人的正常膀胱粘膜含有干细胞衍生的克隆单位，在衰老过程中活跃地补充尿路上皮。可归因于每个干细胞的克隆单位的大小广泛分布，表明一个干细胞克隆被另一个干细胞克隆所取代。版权所有(C)2011年大不列颠和爱尔兰病理学会。作者：John Wiley&Sons，Ltd.
Little is known about the clonal architecture of human urothelium. It is likely that urothelial stem cells reside within the basal epithelial layer, yet lineage tracing from a single stem cell as a means to show the presence of a urothelial stem cell has never been performed. Here, we identify clonally related cell areas within human bladder mucosa in order to visualize epithelial fields maintained by a single founder/stem cell. Sixteen frozen cystectomy specimens were serially sectioned. Patches of cells deficient for the mitochondrially encoded enzyme cytochrome c oxidase (CCO) were identified using dual-colour enzyme histochemistry. To show that these patches represent clonal proliferations, small CCO-proficient and -deficient areas were individually laser-capture microdissected and the entire mitochondrial genome (mtDNA) in each area was PCR amplified and sequenced to identify mtDNA mutations. Immunohistochemistry was performed for the different cell layers of the urothelium and adjacent mesenchyme. CCO-deficient patches could be observed in normal urothelium of all cystectomy specimens. The two-dimensional length of these negative patches varied from 2-3 cells (about 30 mu m) to 4.7 mm. Each cell area within a CCO-deficient patch contained an identical somatic mtDNA mutation, indicating that the patch was a clonal unit. Patches contained all the mature cell differentiation stages present in the urothelium, suggesting the presence of a stem cell. Our results demonstrate that the normal mucosa of human bladder contains stem cell-derived clonal units that actively replenish the urothelium during ageing. The size of the clonal unit attributable to each stem cell was broadly distributed, suggesting replacement of one stem cell clone by another. Copyright (C) 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.