Reply to: “The role of CD147 in liver injury: The truth is in the details”
Authors: Da-Wei Zhang, Zhi-Nan Chen, Huijie Bian
Journal: Journal of Hepatology (2012)

The role of CD147 in liver injury: “The truth is in the details”Journal of HepatologyVol. 58Issue 4PreviewWe have read the manuscript by Zhang et al. with great interest [1]. The results demonstrate an important role for CD147 in liver injury. However, we have published results, which are not referenced by Zhang et al. that appear to contradict some of their findings [2]. Our immunohistochemistry staining for CD147 shows a pattern of expression consistent with hepatocyte and leukocyte specific expression, but with negligible expression by hepatic stellate cells (HSC) [2]. We used a well-characterised commercial monoclonal antibody (MEM-M6/1) [2,3], whilst HAb18G, the antibody used in the manuscript, is not commercially available [1]. Full-Text PDF Open AccessHAb18G/CD147 promotes activation of hepatic stellate cells and is a target for antibody therapy of liver fibrosisJournal of HepatologyVol. 57Issue 6PreviewActivated hepatic stellate cells (HSCs) located in the Disse’s space play a crucial role in liver fibrosis. HAb18G/CD147, a tumor-related glycoprotein, is highly expressed in hepatocellular carcinoma cells and fibroblasts. Whether HAb18G/CD147 plays an important role in the hepatic fibrogenesis is unknown. Full-Text PDF We greatly appreciate the letter by McLennan et al., which discusses our recently published article on the role of HAb18G/CD147 promoting liver fibrosis through activation of hepatic stellate cells (HSCs) [[1]Zhang D.W. Zhao Y.X. Wei D. Li Y.L. Zhang Y. Wu J. et al.HAb18G/CD147 promotes activation of hepatic stellate cells and is a target for antibody therapy of liver fibrosis.J Hepatol. 2012; 57: 1283-1291Abstract Full Text Full Text PDF PubMed Scopus (47) Google Scholar]. In a chronically injured liver, caused by hepatitis B virus (HBV), hepatitis C virus (HCV), alcohol or other factors, HSCs are activated by inflammation mediators and differentiate into myofibroblasts, which play an important role in the development of liver fibrosis and cirrhosis. In China, HBV causes more cases of liver cirrhosis than HCV, therefore our research interest focused on HBV-related liver cirrhosis in our article [[1]Zhang D.W. Zhao Y.X. Wei D. Li Y.L. Zhang Y. Wu J. et al.HAb18G/CD147 promotes activation of hepatic stellate cells and is a target for antibody therapy of liver fibrosis.J Hepatol. 2012; 57: 1283-1291Abstract Full Text Full Text PDF PubMed Scopus (47) Google Scholar]. The published article by Shackel et al. using array analysis compared gene expression of HCV-associated cirrhosis with autoimmune hepatitis-associated cirrhosis, showing a marked difference in the apoptosis-associated gene profile, reflecting the fact that different pathogens lead to different gene expression profiles. However no data were shown in HBV-associated cirrhosis [[2]Shackel N.A. McGuinness P.H. Abbott C.A. Gorrell M.D. McCaughan G.W. Insights into the pathobiology of hepatitis C virus-associated cirrhosis: analysis of intrahepatic differential gene expression.Am J Pathol. 2002; 160: 641-654Abstract Full Text Full Text PDF PubMed Scopus (160) Google Scholar]. The antibody HAb18, for immunohistochemistry (IHC) of human liver cirrhosis tissue, mentioned in our article, has already been used for years in our laboratory, is qualified for Western blot, IHC, immunofluorescent staining, and has been granted international patents (Patent Numbers: PCT/CN03/00188 and PCT/CN2002/000356) [3Li Y. Xu J. Chen L. Zhong W.D. Zhang Z. Mi L. et al.HAb18G (CD147), a cancer-associated biomarker and its role in cancer detection.Histopathology. 2009; 54: 677-687Crossref PubMed Scopus (151) Google Scholar, 4Zhao P. Zhang W. Wang S.J. Yu X.L. Tang J. Huang W. et al.HAb18G/CD147 promotes cell motility by regulating annexin II-activated RhoA and Rac1 signaling pathways in hepatocellular carcinoma cells.Hepatology. 2011; 54: 2012-2024Crossref PubMed Scopus (96) Google Scholar]. The fragment F(ab′)2 of HAb18 labeled with 131I, registered as Licartin, has been approved for the treatment of hepatocellular carcinoma (HCC) by the China State Food and Drug Administration (Registration No. S20050039) [[5]Xu J. Shen Z.Y. Chen X.G. Zhang Q. Bian H.J. Zhu P. et al.A randomized controlled trial of Licartin for preventing hematoma recurrence after liver transplantation.Hepatology. 2007; 45: 269-276Crossref PubMed Scopus (168) Google Scholar]. HAb18 combines with the Ig-C2 domain of isoform Basigin-2, which is the most predominant splice variant, encoding the well-known EMMPRIN/CD147, but not with isoform Basigin-3 [6Ku X.M. Liao C.G. Li Y. Yang X.M. Yang B. Yao X.Y. et al.Epitope mapping of series of monoclonal antibodies against the hepatocellular carcinoma-associated antigen HAb18G/CD147.Scand J Immunol. 2007; 65: 435-443Crossref PubMed Scopus (33) Google Scholar, 7Liao C.G. Kong L.M. Song F. Xing J.L. Wang L.X. Sun Z.J. et al.Characterization of basigin isoforms and the inhibitory function of basigin-3 in human hepatocellular carcinoma proliferation and invasion.Mol Cell Biol. 2011; 31: 2591-2604Crossref PubMed Scopus (64) Google Scholar]. Our previous IHC with commercial mouse anti-human CD147 antibody (NovoCastra) showed immunostaining in the tumor compartment, but not in the stromal compartment, in HCC tissues, which is consistent with our HAb18 staining in cirrhotic tissues, where HAb18G/CD147 was absent in the fibrous septa area [8Zhang Q. Chen X. Zhou J. Zhang L. Zhao Q. Chen G. et al.CD147, MMP-2, MMP-9 and MVD-CD34 are significant predictors of recurrence after liver transplantation in hepatocellular carcinoma patients.Cancer Biol Ther. 2006; 5: 808-814Crossref PubMed Scopus (93) Google Scholar, 1Zhang D.W. Zhao Y.X. Wei D. Li Y.L. Zhang Y. Wu J. et al.HAb18G/CD147 promotes activation of hepatic stellate cells and is a target for antibody therapy of liver fibrosis.J Hepatol. 2012; 57: 1283-1291Abstract Full Text Full Text PDF PubMed Scopus (47) Google Scholar]. In the mouse liver fibrosis model, CD147 expression in activated HSCs was shown with a commercial rat anti-mouse CD147 antibody (Abcam ab34016) by co-localization with alpha-smooth muscle actin (α-SMA) in Disse’s space [[1]Zhang D.W. Zhao Y.X. Wei D. Li Y.L. Zhang Y. Wu J. et al.HAb18G/CD147 promotes activation of hepatic stellate cells and is a target for antibody therapy of liver fibrosis.J Hepatol. 2012; 57: 1283-1291Abstract Full Text Full Text PDF PubMed Scopus (47) Google Scholar]. In our previous study we showed that HAb18G/CD147 was expressed in hepatocytes of cirrhotic and HCC tissues, consistent with Shackel’s paper [9Wu J. Ru N.Y. Zhang Y. Li Y. Wei D. Ren Z. et al.HAb18G/CD147 promotes epithelial–mesenchymal transition through TGF-β signaling and is transcriptionally regulated by Slug.Oncogene. 2011; 30: 4410-4427Crossref PubMed Scopus (138) Google Scholar, 2Shackel N.A. McGuinness P.H. Abbott C.A. Gorrell M.D. McCaughan G.W. Insights into the pathobiology of hepatitis C virus-associated cirrhosis: analysis of intrahepatic differential gene expression.Am J Pathol. 2002; 160: 641-654Abstract Full Text Full Text PDF PubMed Scopus (160) Google Scholar]. The α-SMA-positive cells represent a heterogeneous population, including activated resident fibroblasts, activated HSCs, bone marrow-derived mesenchymal cells and fibrocytes, hepatocytes or biliary epithelium-derived fibroblasts by epithelial-mesenchymal transition, which means that not all of the α-SMA-positive cells are derived from HSCs. Therefore, we identified HSCs by reaction with α-SMA and their localization in the perisinusoidal space. McLennan et al. showed a positive staining of α-SMA by immunofluorescence in fibrotic septa while no immunoreaction with α-SMA was observed in the perisinusoidal space (Fig. 1D). Importantly, fibrous septa composed of collagen have a strong autofluorescence, the specific fluorescence is suggested to be identified by blank and isotype controls. In Fig. 1C of the McLennan’s study, the co-localization of CD147 with CK-18 was observed in hepatocytes, but no CK-18 expression was observed in some CD147 positive cells detected by green fluorescence. LX-2 cell line was originally isolated with property of α-SMA expression detected by immunofluorescence [[10]Xu L. Hui A.Y. Albanis E. Arthur M.J. O’Byrne S.M. Blaner W.S. et al.Human hepatic stellate cell lines, LX-1 and LX-2: new tools for analysis of hepatic fibrosis.Gut. 2005; 54: 142-151Crossref PubMed Scopus (753) Google Scholar]. We also observed a weak immunofluorescent signal of α-SMA expression in our work. However, we did not observe a detectable level of α-SMA protein expression by Western blot, but mRNA expression was detected by real-time PCR in untreated LX-2 cells. Stable transfection with the CD147 gene in LX-2 cells induced a notable α-SMA expression [[1]Zhang D.W. Zhao Y.X. Wei D. Li Y.L. Zhang Y. Wu J. et al.HAb18G/CD147 promotes activation of hepatic stellate cells and is a target for antibody therapy of liver fibrosis.J Hepatol. 2012; 57: 1283-1291Abstract Full Text Full Text PDF PubMed Scopus (47) Google Scholar]. This may be due to a different detection sensitivity and different sources of primary and secondary antibodies. In summary, we have reasons to believe that the HAb18 antibody used by us works properly and that the conclusions drawn from these experiments are valid. This work was supported by Grants from the National Natural Science Foundation of China (No. 81172144), the National Basic Research Program (No. 2009CB521706) and the National Science and Technology Major Projects (Nos. 2012ZX10002-015 and 2012AA020806). The authors who have taken part in this study declared that they do not have anything to disclose regarding funding or conflict of interest with respect to this manuscript.