Cell viability and hepatocyte-typic functions in co-cultures of proliferating and differentiated HepaRG with LX-2 cells

Introduction: In vivo, human stellate cells (HSC) are involved in hepatic development, regeneration, xenobiotic responses and liver injury. One prospect is that cell-cell contacts with HSC are essential for hepatic progenitor cell proliferation and differentiation because HSC´s are involved in vitamin A metabolism, extracellular matrix reorganization, production of various growth factors, and cytokines. Co-cultivation of HepaRG and LX-2 cells could maintain hepatocyte-specific functions. To explore the role of HSC on the hepatocyte-typic functions of proliferative and pre-differentiated HepaRG cells, we co-cultivated with the immortalized cell line (LX-2), which represents partially activated HSCs (1).

Methods: Proliferating or differentiated (14 days treated with 1% DMSO) HepaRG cells, a hepatoma cell line able to differentiate in vitro into hepatocyte-like cells, were co-cultivated with LX-2 cells for 1, 7 or 14 days. Cell proliferation, cell cytotoxicity, CYP450 expression and Albumin secrection was analyzed.

Results: Both HepaRG-LX-2 co-culture models led to a significant cytotoxicity against HepaRG monoculture after 14 days co-cultivation time but not after 1 or 7 days. The results of LDH release were in accordance to the morphological appearance. The co-cultivation of proliferating or differentiated HepaRG cells with LX-2 did not improve CYP1A2 and 3A4 mRNA expression versus HepaRG monoculture over time. Albumin secretion in differentiated HepaRG with LX-2 increased and stayed at the same level over time.

Discussion: Under the used conditions co-cultivation of differentiated HepaRG cells with LX-2 could ameliorate some liver metabolic functions compared to the proliferating HepaRG-LX-2 co-culture, but not in comparison to the differentiated HepaRG cells in monoculture. Both models did not maintain cell functionality over 14 days. Further optimization of culture conditions is necessary to get a stable HepaRG and LX-2 cell co-culture model.

Literatur:

1. Xu L, Hui AY, Albanis E, Arthur MJ, O'Byrne SM, Blaner WS, Mukherjee P, Friedman SL, Eng FJ. Human hepatic stellate cell lines, LX-1 and LX-2: new tools for analysis of hepatic fibrosis. Gut 2005; 54: 142-151

HSC - HepaRG - LX2 - co-culture