Structural polarity and functional bile canaliculi in rat hepatocyte spheroids
| Autor: | Wei Shou Hu, Susan Fugett Abu-Absi, Linda K. Hansen, Julie R. Friend |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
Male
medicine.drug_class Dipeptidyl Peptidase 4 Cell Culture Techniques Biology Bone canaliculus digestive system Models Biological law.invention Tight Junctions Bile Acids and Salts Rats Sprague-Dawley chemistry.chemical_compound Confocal microscopy law medicine Animals Fluorescein Fluorescent Dyes Bile acid Tight junction Bile Canaliculi Spheroid Cell Polarity Cell Biology Cell biology Rats medicine.anatomical_structure Membrane protein chemistry Liver Microscopy Fluorescence Hepatocyte embryonic structures Hepatocytes |
| Zdroj: | Experimental cell research. 274(1) |
| ISSN: | 0014-4827 |
| Popis: | Primary hepatocytes self-assemble into spheroids that possess tight junctions and microvilli-lined channels. We hypothesized that polarity develops gradually and that the channels structurally and functionally resemble bile canaliculi. Immunofluorescence labeling of apical and basolateral proteins demonstrated reorganization of the membrane proteins into a polarized distribution during spheroid culture. By means of fluorescent dextran diffusion and confocal microscopy, an extensive network of channels was revealed in the interior of the spheroids. These channels connected over several planes and opened to pores on the surface. To examine the content of apical proteins in the channel membranes, the bile canalicular enzyme dipeptidyl peptidase IV (DPPIV) was localized using a fluorogenic substrate, Ala-Pro-cresyl violet. The results show that DPPIV activity is heterogeneously distributed in spheroids and localized in part to channels. Bile acid excretion was then investigated to demonstrate functional polarity. A fluorescent bile acid analogue, fluorescein isothiocyanate-labeled glycocholate, was taken up into the spheroids and excreted into bile canalicular channels. Due to the structural polarity of spheroids and their ability to excrete bile into channels, they are a unique three-dimensional model of in vitro liver tissue self-assembly. (Videoanimations of some results are available at http://hugroup.cems.umn.edu/research_movies). |
| Databáze: | OpenAIRE |
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