Laminins in the Developing and Adult Human Small Intestine: Relation With the Functional Absorptive Unit

Here, the expression of the five laminin a-chains was analyzed in the developing and mature human small intestine at the protein and transcript levels in order to further delineate specific involvement of individual laminins in relation to the epithelial cell state as defined along the functional crypt-villus axis. The results show that all of the a-laminins are expressed in significant amounts in the small intestine relative to a panel of other tissues and organs. Distinct epithelial and mesenchymal origins, as well as a differential occurrence in intestinal basement membranes according to developmental stage, along the crypt-villus axis and in compartment-related experimental intestinal cell models. Taken together, the data point out the prime importance of a2-, a3-, and a5-containing laminins for the development and maintenance of the functional human intestinal epithelium.