Abstract
The small intestinal epithelium is a highly dynamic system continuously renewed by a process involving cell proliferation and differentiation. The intestinal epithelium constitutes a permeability barrier regulating the vectorial transport of ions, water, and solutes. Morphological changes during cell differentiation, as well as changes in the activity of brush-border enzymes and the expression of transport proteins, are well established. However, little is known about the arachidonic acid (AA) cascade underlying epithelial cell differentiation or its role in the development of epithelial barrier function. The main purpose of this study was to examine the activity of the high-molecular-weight phospholipases A(2) (PLA(2)) and cyclooxygenase (COX) pathway during differentiation, with particular emphasis on paracellular permeability. PLA(2) activity, AA release, COX-2 expression, prostaglandin E(2) (PGE(2)) production, and paracellular permeability were studied in preconfluent, confluent, and differentiated Caco-2 cell cultures. Our results show that Caco-2 differentiation induces a decrease in both calcium-independent PLA(2) activity and COX-2 expression and, consequently, a decrease in AA release and PGE(2) synthesis in parallel with a reduction in paracellular permeability. Moreover, the addition of PGE(2) to differentiated cells, at concentrations similar to those detected in nondifferentiated cultures, induces the disruption of epithelial barrier function. These results suggest that AA release by calcium-independent PLA(2), COX-2 expression, and subsequent PGE(2) release are important for the maintenance of paracellular permeability in differentiated Caco-2 cells.
Highlights
The small intestinal epithelium is a highly dynamic system continuously renewed by a process involving cell proliferation and differentiation
The results show that total phospholipases A2 (PLA2) activity decreased markedly when Caco-2 cultures reached confluence, with a further decrease observed after differentiation (Table 1)
We observed that Caco-2 cell differentiation is accompanied by marked changes in the arachidonic acid (AA) cascade and that these events can be correlated with the development of epithelial barrier function
Summary
The small intestinal epithelium is a highly dynamic system continuously renewed by a process involving cell proliferation and differentiation. The addition of PGE2 to differentiated cells, at concentrations similar to those detected in nondifferentiated cultures, induces the disruption of epithelial barrier function These results suggest that AA release by calcium-independent PLA2, COX-2 expression, and subsequent PGE2 release are important for the maintenance of paracellular permeability in differentiated Caco-2 cells.—Martın-Venegas, R., S. Caco-2 cells acquire morphological and functional polarity and show enzymatic activities, as well as protein and mRNA levels, of brushborder membrane enzymes and transporters highly comparable to those of mature enterocytes [7,8,9] In this sense, Caco-2 cell cultures provide an important tool for studying and obtaining greater insight into the regulation of human intestinal epithelial cellular processes such as enterocytic differentiation [4, 10].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
