Dynamic distribution of claudin proteins in pancreatic epithelia undergoing morphogenesis or neoplastic transformation

Background: The assembly of distinct proteins into tight junctions results in the formation of a continuous barrier that regulates the paracellular flux of water, ions, and small molecules across epithelia. The claudin protein family encompasses numerous major structural components of tight junctions. These proteins specify the permeability characteristics of tight junctions and consequently, some of the physiological properties of epithelia. Furthermore, defective claudin expression has been found to correlate with some diseases, tumor progression, and defective morphogenesis. Investigating the pattern of claudin expression during embryogenesis or in certain pathological conditions is necessary to begin disclosing the role of these proteins in health and disease. Results: This study analyzed the expression of several claudins during mouse pancreas organogenesis and in pancreatic intraepithelial neoplasias of mouse and human origin. Conclusions: Our results underscored a distinctive, dynamic distribution of certain claudins in both the developing pancreas and the pancreatic epithelium undergoing neoplastic transformation. Developmental Dynamics 241:583–594, 2012. © 2012 Wiley Periodicals Inc. Key findings: Claudin proteins have a dynamic subcellular distribution in the developing pancreatic epithelium Within the postnatal pancreas, subtypes of epithelial cells express a specific complement of claudin proteins The subcellular localization of claudin proteins is altered during neoplastic transformation in the pancreas Cldn18 is not expressed at any stage of pancreas development but is highly expressed in the transformed pancreatic epithelium