Department of Tissue Dynamics and Regeneration, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077 Göttingen, Germany; Graduate Center for Neurosciences, Biophysics, and Molecular Biosciences, University of Göttingen, 37077 Göttingen, Germany.
Department of Tissue Dynamics and Regeneration, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077 Göttingen, Germany.
Cell Rep. 2024 Jul 23;43(7):114305. doi: 10.1016/j.celrep.2024.114305. Epub 2024 Jun 20.
Planarian flatworms undergo continuous internal turnover, wherein old cells are replaced by the division progeny of adult pluripotent stem cells (neoblasts). How cell turnover is carried out at the organismal level remains an intriguing question in planarians and other systems. While previous studies have predominantly focused on neoblast proliferation, little is known about the processes that mediate cell loss during tissue homeostasis. Here, we use the planarian epidermis as a model to study the mechanisms of cell removal. We established a covalent dye-labeling assay and image analysis pipeline to quantify the cell turnover rate in the planarian epidermis. Our findings indicate that the ventral epidermis is highly dynamic and epidermal cells undergo internalization via basal extrusion, followed by a relocation toward the intestine and ultimately digestion by intestinal phagocytes. Overall, our study reveals a complex homeostatic process of cell clearance that may generally allow planarians to catabolize their own cells.
涡虫等扁形动物经历持续的内部更新，在此过程中，旧细胞被成年多能干细胞（成体神经干细胞）的分裂后代所取代。细胞更新如何在整体水平上进行仍然是涡虫和其他系统中的一个有趣问题。尽管之前的研究主要集中在成体神经干细胞的增殖上，但对于介导组织稳态过程中细胞丢失的过程知之甚少。在这里，我们使用扁形动物表皮作为模型来研究细胞去除的机制。我们建立了一个共价染料标记测定和图像分析管道来量化扁形动物表皮中的细胞更新率。我们的研究结果表明，腹侧表皮具有高度动态性，表皮细胞通过基底挤出进行内化，然后向肠迁移，最终被肠吞噬细胞消化。总的来说，我们的研究揭示了一种复杂的细胞清除的稳态过程，这可能使扁形动物能够分解自身的细胞。
