Column Cytotrophoblast Cells (CCL)

The column cytotrophoblast cells are located distal to the villous stroma and acquire invasive characteristics in a process which involves epithelial-mesenchymal transition (EMT), facilitating their migration to, and invasion of, the maternal decidua. The phenotypic switch requires the production and/or secretion of collagenases, metalloproteinases, aminopeptidases, and an assortment of additional enzymes by the cells. The activity of these proteins enables their infiltration into the decidua by promoting degradation of the extracellular matrix. Column cytotrophoblast cells make up the middle layer of the human placenta, and are parallel to the mouse spongiotrophoblast cells in the middle layer of the mouse placenta.