Paracrine in vivo inhibitory effects of hepatitis B virus X protein (HBx) on liver cell proliferation: an alternative mechanism of HBx-related pathogenesis.
The role of the hepatitis B virus X protein (HBx) in the pathogenesis of hepatitis B virus (HBV) infection remains unclear. HBx exhibits pleiotropic biological effects, whose in vivo relevance is a matter for debate. In the present report, we have used a combination of HBx-expressing transgenic mice and liver cell transplantation to investigate the in vivo impact of HBx expression on liver cell proliferation and viability in a regenerative context. We show that moderate HBx expression inhibits liver regeneration after partial hepatectomy in HBx-expressing transgenic mice. We also demonstrate that the transplantation of HBx-expressing liver cells, isolated from HBx transgenic mice, is sufficient to inhibit overall recipient liver regeneration after partial hepatectomy. Moreover, the injection of serum samples drawn from HBx-expressing transgenic mice mimicked the inhibitory effect of HBx on liver regeneration. Finally, the incubation of primary rat hepatocytes with the supernatant of HBx-expressing liver cells inhibits cellular DNA synthesis. Taken together, our results demonstrate a paracrine inhibitory effect of HBx on liver cell proliferation and lead us to propose HBV as one of the few viruses implicated in human cancer which act, at least in part, through paracrine biological pathways.
Tralhao
J Guilherme
JG
Institut Pasteur-Institut National de la Santé et de la Recherche Médicale Unit 370, Necker Institute, 75015 Paris, France.
Roudier
Jean
J
Morosan
Serban
S
Giannini
Carlo
C
Tu
Hong
H
Goulenok
Cyril
C
Carnot
Françoise
F
Zavala
Flora
F
Joulin
Virginie
V
Kremsdorf
Dina
D
Bréchot
Christian
C
D000818:Animals; D002455:Cell Division; D002478:Cells, Cultured; D005260:Female; D015870:Gene Expression; D006515:Hepatitis B virus / Q000235:genetics / Q000378:metabolism*; D022781:Hepatocytes / Q000166:cytology / Q000378:metabolism; D006801:Humans; D008099:Liver / Q000166:cytology / Q000378:metabolism* / Q000821:virology; D008115:Liver Regeneration; D008297:Male; D051379:Mice; D016513:Mice, SCID; D008822:Mice, Transgenic; D019899:Paracrine Communication; D051381:Rats; D017208:Rats, Wistar; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D019076:Transgenes; D014407:Tumor Cells, Cultured; D054334:Viral Regulatory and Accessory Proteins
D015534:Trans-Activators; D054334:Viral Regulatory and Accessory Proteins; C057628:hepatitis B virus X protein