Tubulointia

Tubulointia, or tubulogenesis, is the developmental process by which cells organize into elongated, tube-shaped structures that contain a central lumen. This process underlies the formation of many tubular organs and ducts, such as the kidneys, lungs, liver, pancreas, salivary glands, and parts of the vascular and reproductive systems.

During embryogenesis, tubulointia can proceed through several morphogenetic routes. In cord hollowing, a solid strand of epithelial cells polarizes and forms a central lumen. In cell hollowing, individual cells establish luminal space within a cluster. Wrapping involves sheets of epithelial cells bending and surrounding a space to create a tube. Tubulointia is frequently coupled with branching morphogenesis, which expands a basic tubular structure into a network.

Formation is regulated by cell polarity, cell adhesion, and the extracellular matrix, with signaling pathways such as FGF, WNT, BMP and SHH guiding growth and patterning. Key transcription factors include PAX2, SOX9 and HNF1β in several organ systems, along with cytoskeletal rearrangements driven by Rho family GTPases.

Proper tubulointia is essential for organ function; defects can lead to congenital malformations or impaired organogenesis. In disease and biotechnology, tubulointia is studied in organoids and tissue engineering to model development and to engineer tubular tissues.