Table 7.
Function of claudin 19 and of claudin 16 and claudin 19 co-expression according to heterologous expression studies in cell lines.
| Claudin | Cell Line | Transfection | TER | PNa/PCl | PNa | PCl | PMg | PCa | Ref. |
|---|---|---|---|---|---|---|---|---|---|
| Human CLDN19 | LLC-PK1 | Stable? | ↗ | ↗ | NS | ↘ | † | [47] | |
| Human CLDN19 | MDCK II | Stable? | NS | NS | [47] | ||||
| Mouse Cldn19 | MDCK II Tet-Off cells | Stable inducible expression | ↗ | ↘ | NS | ↘ £∂ | ↘∫∂ | [134] | |
| Human CLDN19 + full length human CLDN16 | LLC-PK1 | Stable? | ↘ | ↗ | ↗ | ↘ | ↘ † | [47] |
Relative epithelial permeabilities (e.g., PNa/PCl) are calculated using the Goldman-Hodgkin-Katz equation and the diffusion potential caused by the application of distinct solutions at the apical and basolateral compartment. Absolute permeabilities can be calculated if the transepithelial conductance is known using Kimizuka-Koketsu equation [41]. TER: trans epithelial resistance; NS: not significantly different from control; Px: permeability to ion X; ∫: Transepithelial transport of 45Ca2+ measurement; †: The permeability of Mg2+ across monolayers was determined according to Tang and Goodenough [133]; £: Mg2+ flux was measured employing atomic absorption spectrometry; ∂: Permeability PC = Flux/Substrate concentration in cis compartment. This was then corrected for the permeability of blank filters, PB, to obtain the true transepithelial permeability (PT), using the following equation PT = [(1/PC) & (1/PB)]−1.