肢芽 limb budの細胞は上皮間葉転換によって生じた間葉系細胞か？

 

 

四肢の形成の分子シグナル

ニワトリ胚を使った実験で、FGF4産生細胞を脇腹（本来四肢が生じない場所）に移植すると、そこにエキストラの肢芽が生えてきて脚になるということが示されています。

  1. An Additional Limb Can Be Induced from the Flank of the Chick Embryo by FGF4 Biochemical and Biophysical Research Communications Volume 209, Issue 3, 26 April 1995, Pages 809-816

 

肢芽 limb budの細胞は上皮間葉転換によって生じた間葉系細胞か

consensus.aiに訊いてみました。

The formation of vertebrate limb buds is a critical process in developmental biology, involving the transformation of specific cells to initiate limb development. This process is believed to be driven by epithelial-to-mesenchymal transition (EMT), where epithelial cells convert into mesenchymal cells, which are more migratory and capable of forming the limb structure.

Key Insights

  • Localized EMT Initiates Limb Bud Formation:
    • Limb buds form through a localized EMT of the coelomic epithelium within the presumptive limb fields, regulated by genes such as Tbx5 and Fgf10 .
    • The mesenchymal limb progenitors arise specifically from this EMT process, rather than from differential cell proliferation .
  • Role of Lateral Plate Mesoderm (LPM):
    • The somatic LPM undergoes EMT to produce mesenchymal cells that contribute to limb bud formation. This process is driven by transcriptional regulators like PRRX1 and TWIST1, although further functional data are needed to fully understand these mechanisms.
  • Epithelial-Mesenchymal Interactions:
    • Limb bud development involves interactions between the mesenchymal cells of the lateral plate mesoderm and the overlying ectodermal cells, highlighting the importance of epithelial-mesenchymal interactions in early morphogenesis .
  • In Vitro Limb Bud Formation:
    • Limb bud-like tissues can be induced from murine pluripotent stem cells in vitro, demonstrating the potential to recreate the mesenchymal/epithelial complex tissues necessary for limb development.

Conclusion

The origin of limb buds is indeed mesenchymal cells derived from epithelial-to-mesenchymal transition. This process is initiated by localized EMT in the coelomic epithelium and the somatic lateral plate mesoderm, regulated by specific genes and involving critical epithelial-mesenchymal interactions. These findings underscore the fundamental role of EMT in the early stages of limb bud formation.

  1. Vertebrate Limb bud formation is initiated by localized Epithelial to Mesenchymal Transition Jerome Gros 1,#, Clifford J Tabin　Science. 2014 Mar 14;343(6176):1253–1256. doi: 10.1126/science.1248228 https://pmc.ncbi.nlm.nih.gov/articles/PMC4097009/