ABSTRACT
Background and aims Cell-cell adhesion structures (desmosomes and, especially, tight junctions) are known to play important roles in control of transepithelial permeability in the colon. The involvement of cell-matrix interactions in permeability control is less clear. The goals of the present study were to: i) determine if disruption of colon epithelial cell interactions with the extracellular matrix alters permeability control and ii) determine if increasing the elaboration of protein components of cell-matrix adhesion complexes improves permeability control and mitigates the effects of cell-matrix disruption.
Methods Human colon organoids were interrogated for transepithelial electrical resistance (TEER) under control conditions (0.25 mM calcium) and in the presence of Aquamin®, a multi-mineral product, at a level providing 1.5 mM calcium. The effects of Aquamin® on cell-matrix adhesion protein expression were determined in a proteomic screen and by Western blotting. In parallel, TEER was assessed in the presence of a function-blocking antibody directed at an epitope in the C-terminal region of laminin α3 chain.
Results Treatment of colon organoids with Aquamin® increased the expression of multiple basement membrane and hemidesmosomal proteins as well as keratin 8 and 18. TEER values were higher in the presence of Aquamin® than they were under control conditions. Anti-laminin antibody reduced TEER values under all conditions but was most effective in the absence of Aquamin®, where laminin expression was low and TEER values were lower to begin with.
Conclusions These findings provide evidence that cell-matrix interactions contribute to permeability control in the colon. They suggest that the elaboration of proteins important to cell-matrix interactions can be increased in human colon organoids by exposure to a multi-mineral natural product. Increasing the elaboration of such proteins may help to mitigate the consequences of disrupting cell-matrix interactions on permeability control.
Competing Interest Statement
The authors have declared no competing interest.
