Mosaic analysis of stem cell function and wound healing in the mouse corneal epithelium.
Mosaic analysis of stem cell function and wound healing in the mouse corneal epithelium.
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DOI：
10.1186/1471-213x-9-4
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发表时间：
2009-01-07
影响因子：
--
通讯作者：
West JD
中科院分区：
文献类型：
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作者：
Mort RL;Ramaesh T;Kleinjan DA;Morley SD;West JD
小鼠角膜上皮是覆盖在角膜表面的一层不断更新的5-6个细胞厚的保护层，损伤后再生迅速。它是由位于外周的边缘干细胞（LSCs）维持的，这些干细胞产生瞬时扩增细胞（tac），这些细胞增殖、向心迁移、分化并最终从上皮表面脱落。LSC活性对于正常组织维持和伤口愈合都是必需的。镶嵌分析可以深入了解组织维护和修复过程中LSC的功能、细胞运动和细胞混合。本研究探讨了角膜维持和修复过程中的细胞流动以及LSC功能随年龄的变化。出生后，XLacZ+/- x失活嵌合体中角膜上皮斑块的初始模式被径向条纹所取代，表明LSCs被激活。条纹图案（顺时针，逆时针或中线）在成对的眼睛之间是独立的。采用XLacZ+/-眼镶嵌分析或GFP镶嵌延时成像分析器官培养创面愈合情况。中心和外周伤口都是克隆愈合的，细胞从伤口周围移动而没有明显的细胞混合，以重建条纹图案。马赛克分析显示伤口可以不对称愈合。周围创面愈合后产生的条纹图案与未受伤角膜中观察到的一些异常条纹图案相似。定量分析没有提供LSC克隆分布不均匀的证据，但显示校正后的角膜上皮条纹数量随着年龄的增长而下降（这意味着LSC功能下降），但在39周后稳定下来。由向心运动产生的条纹图案在单个眼睛中是独立和随机定义的。在伤口愈合的初始阶段很少发生细胞混合，细胞运动的方向由伤口的位置决定，而不是由边缘的种群压力决定。LSC功能随着年龄的增长而下降，这可能反映了LSC数量的减少，更多的静止LSC或老年干细胞维持组织稳态的能力下降。LSC功能的平台期较晚可能表明LSC的最低功能足以维持角膜上皮的维持。定量和时间镶嵌分析为研究干细胞功能、组织维持和修复提供了新的可能性。
The mouse corneal epithelium is a continuously renewing 5–6 cell thick protective layer covering the corneal surface, which regenerates rapidly when injured. It is maintained by peripherally located limbal stem cells (LSCs) that produce transient amplifying cells (TACs) which proliferate, migrate centripetally, differentiate and are eventually shed from the epithelial surface. LSC activity is required both for normal tissue maintenance and wound healing. Mosaic analysis can provide insights into LSC function, cell movement and cell mixing during tissue maintenance and repair. The present study investigates cell streaming during corneal maintenance and repair and changes in LSC function with age. The initial pattern of corneal epithelial patches in XLacZ+/- X-inactivation mosaics was replaced after birth by radial stripes, indicating activation of LSCs. Stripe patterns (clockwise, anticlockwise or midline) were independent between paired eyes. Wound healing in organ culture was analysed by mosaic analysis of XLacZ+/- eyes or time-lapse imaging of GFP mosaics. Both central and peripheral wounds healed clonally, with cells moving in from all around the wound circumference without significant cell mixing, to reconstitute striping patterns. Mosaic analysis revealed that wounds can heal asymmetrically. Healing of peripheral wounds produced stripe patterns that mimicked some aberrant striping patterns observed in unwounded corneas. Quantitative analysis provided no evidence for an uneven distribution of LSC clones but showed that corrected corneal epithelial stripe numbers declined with age (implying declining LSC function) but stabilised after 39 weeks. Striping patterns, produced by centripetal movement, are defined independently and stochastically in individual eyes. Little cell mixing occurs during the initial phase of wound healing and the direction of cell movement is determined by the position of the wound and not by population pressure from the limbus. LSC function declines with age and this may reflect reduced LSCs numbers, more quiescent LSCs or a reduced ability of older stem cells to maintain tissue homeostasis. The later plateau of LSC function might indicate the minimum LSC function that is sufficient for corneal epithelial maintenance. Quantitative and temporal mosaic analyses provide new possibilities for studying stem cell function, tissue maintenance and repair.