An appropriate selection of 3D alginate culture model for hepatic Huh-7 cell line encapsulation intended for viral studies
Résumé
Three-dimensional (3D) culture systems have been introduced to provide cells with a biomimetic environment similar to in vivo conditions. Among the polymeric molecules available, sodium alginate salt (Na-alg) is a material currently employed in different areas of drug delivery and tissue engineering because it offers biocompatibility, optimal chemical properties and its gelation with calcium chloride provides calcium alginate (Ca-alg) scaffolds with mechanical stability and relative permeability. In this work, four different preparations of Ca-alg beads with varying Na-alg viscosity and concentration were used for a human hepatoma cell line (Huh-7) encapsulation. The effects of Ca-alg bead preparation on structural cell organization, liver-specific functions, and specific receptors expression implicated in hepatotropic virus permissivity were evaluated. Hepatic cells were cultured in 500Am diameter Ca-alg beads during 7 days under dynamic condition. For all culture systems, cell viability reached almost 100% at day 7. Cell proliferation was concomitantly followed by hepatocyte organization in aggregates, which adopted two different morphologies (spheroïd aggregates or multicellular channel-like structures), depending on Ca-alg bead preparation. These cellular organizations established real 3D hepatocyte architecture with cell polarity, cell junctions and abundant bile canaliculi possessing microvillus-lined channels. The functionality of these 3D cultures was confirmed by the production of albumin and the exhibition of activity CYP1A over culture time, which were variable, according to Ca-alg bead condition. The expression of specific receptors of Hepatitis C Virus (HCV) by Huh-7 cells suggests encouraging data for further development of a new viral culture system in Ca-alg beads. In summary, this 3D hepatic cell culture represents a promising physiologically relevant system for further in vitro studies and demonstrates that adequate encapsulation condition can be selected for each target application in liver tissue engineering, specifically in viral studies.