- at least 3-7 days post-confluent (take a few rounds of cell division to evolve from flat, spread-contacted confluent
monolayer to densely packed cuboidal or columnar cells), monolayer at "steady-state", i.e. cell division = turnover
- epithelial cells are FULLY polarized
-
intercellular structures are FULLY formed and maintained at "steady-state", i.e. synthesis = turnover
- Tight Juntion
Barrrier COMPLETELY formed, i.e. impermeable to macromolecules
(B) "Newly-Plated-confluent"
Environment:
- less than 36 hours post-plating at confluent density (before the first round of cell division), monolayer at
"growth-state", i.e. cell division > turnover
- epithelial cells are PARTIALLY polarized
- intercellular
sturctures are PARTIALLY formed and at "dynamic-state", i.e. synthesis > turnover
- Tight Juntion Barrrier NOT
completely formed, i.e. permeable to macromolecules
(C) "Pseudo-Steady-State"
Environment:
- Newly confluent monolayer after plating at low density (after plating at low density, cells grow as islands;
cells in middle of islands begin to polarize and form intercellular junctions while cells at periphery spread and grow), at
confluency, part monolayer at "growth-state", part at "steady-state"
- at confluency, monlayer is heterogeneous
populations of FULLY and PARTIALLY polarized cells
- Some intercellular sturctures are at "dynamic-state", some at "steady-state"
- Tight Juntion Barrrier NOT completely
formed, i.e. permeable to macromolecules
(D) "Calcium-Switched
confluent" Environment:
- cells plated at confluent density 24-48 hours in advance and allow to grow in low calcium (<50 microM) and
monitored at various times (hours to days) after addition of normal calcium to growth media; initially, cells are at "growth-state"
(hours), after a few cell divisions (days), cells are at "steady-state"
- synchronized polarization of cells
-
synchronized formation of intercellular sturctures; initiallly (hours) tight junction is at "dynamic-state", after monolayer
reaches "steady-state" (days), tight junction also reaches "steady-state"
- Tight Juntion Barrrier NOT completely
formed until "steady-state"
(E) "Newly-Plated-Subconfluent"
Environment:
- less than 36 hr post-plating at SUB-confluent density (before the first round of cell division),
monolayer at "growth-state"
- Epithelial cells are PARTIALLY polarized
- free edges and PARTIALLY intercellular sturctures at "dynamic-state"
-
Tight Juntion Barrrier NOT completely formed, i.e. permeable to macromolecules
