Low asialoglycoprotein receptor expression as markers for highly proliferative potential hepatocytes

Development of a reliable method to isolate highly proliferative potential hepatocytes will provide insight into the molecular mechanisms of liver reg eneration, as well as proving crucial for the development of a biohybrid ar tificial liver. The aim of this study is to isolate highly proliferative, e .g., progenitor-like, hepatocytes. To this end, we fractionated hepatocytes expressing low and high levels of the asialoglycoprotein receptor (ASGP-R) based on the difference in their adhesion to poly[N-p-vinylbenzyl-O-beta - D-galactopyranosyl-(1 -->4)-D-gluconamide] (PVLA), and examined the prolife rative activity and gene expression of these fractionated hepatocytes. The results showed that approximately 0.5 to 1% of the total number of hepatocy tes, which showed low adhesion to PVLA, expressed low levels of the ASGP-R, while the rest of hepatocyte population with high adhesion to PVLA express ed high levels of the ASGP-R. Interestingly hepatocytes with low ASGP-R exp ression levels had much higher DNA synthesizing activity (i.e., are much mo re proliferative) than those with high ASGP-R expression levels. Moreover, hepatocytes with low ASGP-R expression levels expressed higher levels of ep idermal growth factor receptor (EGF-R), CD29 (beta1 integrin) and CD49f (al pha6 integrin) and lower levels of glutamine synthetase than those with hig h ASGP-R expression. These findings suggested that hepatocytes with low adh esion to PVLA due to their low ASGP-R expression could be potential candida tes for progenitor-like hepatocytes due to their high proliferative capacit y; hence, the low expression of the ASGP-R could be a unique marker for pro genitor hepatocytes. The isolation of hepatocytes with different functional phenotypes using PVLA may provide a new research tool for a better underst anding of the biology of hepatocytes and the mechanisms regulating their pr oliferation and differentiation in health and disease. (C) 2001 Academic Pr ess.