Long-term biosynthesis of complement component C3 and α-1 acid glycoprotein by adult rat hepatocytes in a co-culture system with an epithelial liver cell-type

Abstract

We used a system of co-culture of adult rat hepatocytes with another epithelial cell type from rat liver to study the synthesis of two acute-phase reactants, alpha-1 acid glycoprotein (alpha 1AGP) and the third component of complement (C3), and we have obtained long-term secretion of these two proteins. After a period of adaptation corresponding to the first 2-4 days of the co-culture, hepatocytes secreted C3 and alpha 1AGP for at least 2 weeks at a mean level higher than that observed in the first days of a pure culture of hepatocytes. When pulse-chase analysis was performed on day 6 of co-culture, kinetics of synthesis of alpha 1AGP and C3 were the same as those observed on day 1 of a conventional culture of pure hepatocytes. Furthermore, intracellular and extracellular alpha 1AGP had Mr values respectively of 39,000 and of 42,000-52,000, identical with those observed in pure cultures of hepatocytes. Similarly, the molecular size and subunit structures of C3 were the same in co-culture and in cultures, indicating an identical processing of this protein. C3 produced in co-culture was also haemolytically active. Therefore, the system of adult hepatocytes co-cultured with this liver epithelial cell provides a physiological system in vitro which permits long-term synthesis of the two acute-phase reactants C3 and alpha 1AGP. This model opens the possibility to study the modulation of the synthesis of these two proteins during a long period by inflammatory agents or by hormones.

Lipoprotein metabolism in a coculture system with eel skeletal muscle cells and hepatocytes

“…It was reported that hepatocytes were cocultured with non-parenchymal cells of liver and this coculture system succeeded in the maintenance of liver functions for a long term. [23][24][25] The coculture system in the present study seems available for investigation of lipid transport from hepatocytes to muscle cells, probably also for other studies on cellular interaction between these cells.…”

Perifusion of co-cultured hepatocytes: optimization of studies on drug metabolism and cytotoxicity in vitro

“…This unfavorable situation is considerably improved if the hepatocytes are co-cultured with liver epithelial cell lines (Guguen- Guillouzo and Guillouzo, 1983;GuguenGuillouzo et al, 1983;Begue et al, 1984;Wegner et al, 1990). Co-cultivation not only prolonged the lifespan of the cultured hepatocytes, but also maintained their functional capacity and enhanced their response to various inducing agents (Clement et al, 1984;Lebreton et al, 1986;Foliot et al, 1985;Vandenberghe et al, 1988;Schrode et al, 1990;Wegner et al, 1990). There is increasing evidence that co-cultures are better suited for studies on the metabolism of xenobiotics than pure cultures of rat hepatocytes (Rogiers et al, 1990;Donato et al, 1991;Niemann et al, 1991;Akrawi et al, 1993;Coecke et al, 1993).…”

Liver cell models in in vitro toxicology.

“…A considerable step forward in long-term maintenance of differentiated hepatocytes was made by adding another liver epithelial cell type (126). When cocultured with rat liver epithelial cells probably derived from primitive biliary cells, hepatocytes from various species including humans survive for several weeks and retain various liverspecific functions; these include production of plasma proteins, expression of both phase I and phase II drug metabolizing enzymes, and taurocholate uptake (52,71,(127)(128)(129)(130)(131)(132)(133)(134)(135) (71,126,128) and with preservation of communication through gap junctions (136). These two features could be related because in pure hepatocyte cultures the addition of proteoglycans improves gap junction activity (137).…”