The caudal regeneration blastema is an accumulation of rapidly proliferating stem cells in the flatworm Macrostomum lignano.
The caudal regeneration blastema is an accumulation of rapidly proliferating stem cells in the flatworm Macrostomum lignano.
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DOI：
10.1186/1471-213x-9-41
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发表时间：
2009-07-15
影响因子：
--
通讯作者：
Salvenmoser W
中科院分区：
文献类型：
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作者：
Egger B;Gschwentner R;Hess MW;Nimeth KT;Adamski Z;Willems M;Rieger R;Salvenmoser W
Macrostomum lignano是一种小型的自由生活的扁形虫，能够再生咽后部和大脑前部的所有身体部位。我们量化了尾侧体部区域（尾板）的细胞组成，并研究了尾板在体内和用溴脱氧尿苷（S期干细胞（新生细胞）的标记物）标记的半薄切片中的再生。尾板容纳雄性生殖器，由约3，100个细胞组成，其中约一半是表皮细胞。一个独特的再生芽基，其特征在于由快速增殖的neoblast的局部积累，并由约420个细胞（不包括表皮细胞），截肢后24小时形成。在截肢后两天观察到芽基中的分化细胞（约920个芽基细胞），而男性生殖器需要4至5天才能完全分化。在所有时间点，在芽基内发现有丝分裂。在器官分化部位，新生细胞不进行复制和分裂。培养3天后，芽基由约1420个细胞组成，并逐渐转化为器官原基，但增殖速度下降。在该时间点，包括约960个表皮细胞的尾板细胞数恢复至75%。人工切断木质大口口线虫成虫尾板后的再生过程包括伤口愈合和再生芽基的形成。新胚细胞在胚基内进行广泛的增殖。S期新生细胞的增殖模式表明，新生细胞要么被确定为遵循特定的细胞命运，而不是之前，而是经过S期后，或者它们可以在S期后重新确定。在脉冲追踪实验中，分散分布的标记表明，S-期标记的男性生殖器祖细胞分化前进行进一步的增殖，与表皮细胞的祖细胞。芽基内的有丝分裂活动和增殖是M. lignano与许多其他再生动物共享。
Macrostomum lignano is a small free-living flatworm capable of regenerating all body parts posterior of the pharynx and anterior to the brain. We quantified the cellular composition of the caudal-most body region, the tail plate, and investigated regeneration of the tail plate in vivo and in semithin sections labeled with bromodeoxyuridine, a marker for stem cells (neoblasts) in S-phase. The tail plate accomodates the male genital apparatus and consists of about 3,100 cells, about half of which are epidermal cells. A distinct regeneration blastema, characterized by a local accumulation of rapidly proliferating neoblasts and consisting of about 420 cells (excluding epidermal cells), was formed 24 hours after amputation. Differentiated cells in the blastema were observed two days after amputation (with about 920 blastema cells), while the male genital apparatus required four to five days for full differentiation. At all time points, mitoses were found within the blastema. At the place of organ differentiation, neoblasts did not replicate or divide. After three days, the blastema was made of about 1420 cells and gradually transformed into organ primordia, while the proliferation rate decreased. The cell number of the tail plate, including about 960 epidermal cells, was restored to 75% at this time point. Regeneration after artificial amputation of the tail plate of adult specimens of Macrostomum lignano involves wound healing and the formation of a regeneration blastema. Neoblasts undergo extensive proliferation within the blastema. Proliferation patterns of S-phase neoblasts indicate that neoblasts are either determined to follow a specific cell fate not before, but after going through S-phase, or that they can be redetermined after S-phase. In pulse-chase experiments, dispersed distribution of label suggests that S-phase labeled progenitor cells of the male genital apparatus undergo further proliferation before differentiation, in contrast to progenitor cells of epidermal cells. Mitotic activity and proliferation within the blastema is a feature of M. lignano shared with many other regenerating animals.