Regulation of cultured rat hepatocyte proliferation by stellate cells.
OBJECTIVE
This study using primary culture models was aimed to reveal the stellate cell-derived factors that regulate hepatocyte proliferation.


METHODS
Rat hepatocytes and stellate cells were cultured in serum-free Williams-E medium. We prepared hepatocyte mono-culture and two different co-cultures of hepatocytes and stellate cells; (1) co-culture on the same surface (Co-mix.) and (2) co-culture without contact between hepatocytes and stellate cells using a culture insert (Co-sep.). The change in the number and the DNA synthesis of hepatocytes was evaluated.


RESULTS
The number of hepatocytes decreased to 76% of the original number after 48 h of starting mono-culture, while it remained at 106% in mixed co-culture (Co-mix.) and increased to 135% in separated co-culture (Co-sep.). The hepatocyte DNA synthesis was enhanced by carbenoxolone in Co-mix. and reduced by NK1 in each co-culture. PD153035 had no effect. Heparitinase-I (20 mU/ml) and sodium chrolate (25 mM) reduced the hepatocyte DNA synthesis in Co-sep. to 71.8 and 61.6%, respectively. Activation of mitogen-activated protein kinase was induced in hepatocytes stimulated by conditioned mediums.


CONCLUSIONS
Hepatocyte proliferation was stimulated in the presence of stellate cells through hepatocyte growth factor, extracellular heparan sulfate (HS), and HS proteoglycan, and might be negatively regulated by gap junction-dependent mechanism.
Uyama
Naoki
N
Department of Gastroenterological Surgery, Graduate School of Medicine, Kyoto University, 54-Kawaracho, Shogoin, Sakyoku, Kyoto 606 8507, Japan. uynk@f2.dion.ne.jp
Shimahara
Yasuyuki
Y
Kawada
Norifumi
N
Seki
Shuichi
S
Okuyama
Hiroaki
H
Iimuro
Yuji
Y
Yamaoka
Yoshio
Y
D000418:Albumins / Q000096:biosynthesis; D000818:Animals; D000897:Anti-Ulcer Agents / Q000494:pharmacology; D000925:Anticoagulants / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000494:pharmacology; D002229:Carbenoxolone / Q000494:pharmacology; D002450:Cell Communication / Q000502:physiology*; D002452:Cell Count; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D018920:Coculture Techniques; D017077:Culture Media, Conditioned / Q000494:pharmacology; D004247:DNA / Q000096:biosynthesis; D066246:ErbB Receptors / Q000096:biosynthesis; D017629:Gap Junctions / Q000187:drug effects / Q000502:physiology; D019812:Heparan Sulfate Proteoglycans / Q000494:pharmacology; D006493:Heparin / Q000494:pharmacology; D006497:Heparan Sulfate / Q000494:pharmacology; D017228:Hepatocyte Growth Factor / Q000494:pharmacology; D022781:Hepatocytes / Q000166:cytology* / Q000378:metabolism; D008297:Male; D019859:Proto-Oncogene Proteins c-met / Q000096:biosynthesis; D011799:Quinazolines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013047:Specific Pathogen-Free Organisms
D000418:Albumins; D000897:Anti-Ulcer Agents; D000925:Anticoagulants; D000970:Antineoplastic Agents; D002229:Carbenoxolone; D017077:Culture Media, Conditioned; D004247:DNA; D066246:ErbB Receptors; D019812:Heparan Sulfate Proteoglycans; D006493:Heparin; D006497:Heparan Sulfate; D017228:Hepatocyte Growth Factor; D019859:Proto-Oncogene Proteins c-met; D011799:Quinazolines; C088860:4-((3-bromophenyl)amino)-6,7-dimethoxyquinazoline