Bile acids induce hepatic stellate cell proliferation via activation of the epidermal growth factor receptor
Authors: Francesco Ridolfi
Antonio Benedetti
Manon Homan
Cinzia Candelaresi
Peter L M Jansen
Samuele De Minicis
Stefania Saccomanno
Gianluca Svegliati-Baroni
Han Moshage
Rebekka Hannivoort
Journal: Gastroenterology (2005)
Discipline: CLINICAL MEDICINE
Keywords: Hepatic stellate cell; liver fibrosis; bile acids; proliferation; apoptosis
Affiliations: Department of Gastroenterology, University of Ancona, Italy.

Abstract:  Background &amp; aims: Hepatic stellate cell (HSC) proliferation is a key event in the development of liver fibrosis. In many liver diseases, HSCs are exposed to inflammatory cytokines, reactive oxygen species, and bile acids. Although inflammatory cytokines and reactive oxygen species are known to promote proliferation of HSCs, nothing is known about the effects of bile acids on HSC proliferation or apoptosis. The aim of this study was to investigate the effects of bile acids on HSC proliferation. Methods: HSCs were exposed to bile acids with different hydrophobicity (5-200 micromol/L). HSC proliferation and cell cycle-related events were assessed by bromodeoxyuridine incorporation, cell counting and proliferating cell nuclear antigen and cyclin E expression, apoptosis by caspase-3 activity assay, immunocytochemistry for active caspase-3 and acridine orange staining, and activation of signal transduction pathways by Western blot using phospho-specific antibodies. Uptake of bile acids was investigated using fluorescent bile acids. Results: All bile acids, at concentrations &gt;25 micromol/L, induce a 2.5- to 3-fold increase in HSC proliferation via activation of the epidermal growth factor receptor. Bile acid-induced proliferation is mediated by activation of a protein kinase C/extracellular signal-regulated kinase/p70S6K-dependent pathway. Bile acids did not induce apoptosis in HSCs. HSCs do not take up fluorescent bile acids and do not express the bile acid importer ntcp. Conclusions: Bile acids at levels reached in cholestatic conditions are an independent profibrogenic factor. Bile acids induce HSC proliferation via the activation of the epidermal growth factor receptor, whereas HSCs are protected against bile acid-induced apoptosis by excluding bile acids. 

Retracted: No

PubPeer comments:
 Similar beta actin. The inmage is rotated by 180 ![file] , 
 UNusually similar bands. Different background. Can the authors provide the original gen and beta actin as well? ![file] , 
 Unlikely to be the same gels. The control actins in these images fail to match with other bands. Originals images are needed. ![file] , 
 Figure 12. A vertical bar is seen on the right panel *[red arrow]* reporting the expression of NTCP. The same separation is not seen on GAPDH *[left panel].* Indicating perhaps a different source of these images. ![file] , 
 Please check for protein migration patterns in these images. According to pattern of migration it is hard to believe that beta actins and pERK in eeach panel are from the same gel. Could the authors provide the uncropped films used to prepare these panels. Check protein sizes in panel A. ERKs fail to match the size of beta actins. Also in panel B, the last ERK is completely out of context in comparison to lane 3 and 4. In panel C ERKs have different size than beta actin. In panel D, pERK in lane 2 is of different size compared to the rest of ERKs and all ERKs but #2, are of different sizes compared to beta actins. ![file] , 
 This paper shares a duplicated image with Liver international 2007 10.1111 j.1478-3231.2007.01443.x. The duplicated images have been used to show pEGFR (185 kd) in the Gastroenterology paper 2005, and Beta actin (42 kd) in the Liver International paper. Additionally, the first band from left (green square) in in one or both figures has been manipulated. Could the authors provide the uncropped scans of these images to clarify at least the last question? More on these figures: https: pubpeer.com publications 7EA6E844859C59451C6A6B326185EF ![file] , 
 Figure 9. Duplicated image in panel B and C of this Figure. The same WB has been used for EGFr in different settings. Will the authors provide the uncropped scans used to prepare these panels.? ![file] , 
 Same band for pAKT and actin. One of the two has been reversed. Check for smears. ![file] , 
 ![file] ,