Figure 9.

Schematic Representation of the LG Lineage

Multipotent LG progenitor/stem cells exist in the embryonic LG and early postnatal development and give rise to all cell lineages.

(A) Multipotent LG progenitor/stem cells co-express common markers identified early in LG development. The Sox10-negative cells give rise to ductal lineages, whereas Sox10-positive progenitor give rise to acinar and MEC lineages.

(B and C) (B) Embryonic LG progenitor cells become predisposed toward one lineage as development proceeds and adopt specific marker profiles and location within the epithelium. This lineage restriction may happen at different time in each lineage. For example, MEC lineage is established very early during embryonic development (A), whereas ductal cell lineage is established later during postnatal development. At the same time unipotent MECs in postnatal and adult LGs have certain level of plasticity and may undergo in vivo reprogramming induced by LG injury (C). Thus, the MECs may have reserved MEC progenitors able to help with LG repair after injury (red arrow). (C) It is possible that common progenitor of MEC and acinar lineages is localized in the intercalated ducts (dashed arrow). Solid arrows, reported connections; dashed arrows, possible connections.

See also Figure S9.