Department of Genetics, Harvard Medical School, Boston, MA 02115, USA.
Science. 2013 Oct 11;342(6155):212-8. doi: 10.1126/science.1238842. Epub 2013 Aug 29.
The villi of the human and chick gut are formed in similar stepwise progressions, wherein the mesenchyme and attached epithelium first fold into longitudinal ridges, then a zigzag pattern, and lastly individual villi. We find that these steps of villification depend on the sequential differentiation of the distinct smooth muscle layers of the gut, which restrict the expansion of the growing endoderm and mesenchyme, generating compressive stresses that lead to their buckling and folding. A quantitative computational model, incorporating measured properties of the developing gut, recapitulates the morphological patterns seen during villification in a variety of species. These results provide a mechanistic understanding of the formation of these elaborations of the lining of the gut, essential for providing sufficient surface area for nutrient absorption.
人类和鸡的肠道绒毛以相似的逐步方式形成，其中间充质和附着的上皮首先折叠成纵向脊，然后是之字形图案，最后是单个绒毛。我们发现，这些绒毛形成的步骤取决于肠道不同平滑肌层的顺序分化，这些平滑肌层限制了不断生长的内胚层和间充质的扩张，产生压缩应力，导致它们的弯曲和折叠。一个定量计算模型，结合了发育中肠道的测量特性，再现了各种物种中绒毛形成过程中的形态模式。这些结果提供了对肠道衬里这些复杂结构形成的机制理解，这对于提供足够的表面积以吸收营养物质是必不可少的。
