Ze-yang Ding

Transforming growth factor β induces expression of connective tissue growth factor in hepatic progenitor cells through Smad independent signaling

Hepatic progenitor cells (HPCs) are activated in the chronic liver injury and are found to participate in the progression of liver fibrosis, while the precise role of HPCs in liver fibrosis remains largely elusive. In this study, by immunostaining of human liver sections, we confirmed that HPCs were activated in the cirrhotic liver and secreted transforming growth factor β (TGF-β) and connective tissue growth factor (CTGF), both of which were important inducers of liver fibrosis. Besides, we used HPC cell lines LE/6 and WB-F344 as in vitro models and found that TGF-β induced secretion of CTGF in HPCs. Moreover, TGF-β signaling was intracrine activated and contributed to autonomous secretion of CTGF in HPCs. Furthermore, we found that TGF-β induced expression of CTGF was not mediated by TGF-β activated Smad signaling but mediated by TGF-β activated Erk, JNK and p38 MAPK signaling. Taken together, our results provide evidence for the role of HPCs in liver fibrosis and suggest that the production of CTGF by TGF-β activated MAPK signaling in HPCs may be a therapeutic target of liver fibrosis.

Reduced expression of transcriptional intermediary factor 1 gamma promotes metastasis and indicates poor prognosis of hepatocellular carcinoma

Transcriptional intermediary factor 1 gamma (TIF1γ) may play either a potential tumor‐suppressor or ‐promoter role in cancer. Here we report on a critical role of TIF1γ in the progression of hepatocellular carcinoma (HCC). Reduced expression of TIF1γ was detected in HCC, especially in advanced HCC tissues, compared to adjacent noncancerous tissues. HCC patients with low TIF1γ expression had shorter overall survival times and higher recurrence rates than those with high TIF1γ expression. Reduced TIF1γ expression was an independent and significant risk factor for recurrence and survival after curative resection. In HCC cells, TIF1γ played a dual role: It promoted tumor growth in early‐stage HCC, but not in advanced‐stage HCC, whereas it inhibited invasion and metastasis in both early‐ and advanced‐stage HCC. Mechanistically, we confirmed that TIF1γ inhibited transforming growth factor‐β/ Drosophila mothers against decapentaplegic protein (TGF‐β/Smad) signaling through monoubiquitination of Smad4 and suppressed the formation of Smad2/3/4 complex in HCC cells. TGF‐β‐inducing cytostasis and metastasis were both inhibited by TIF1γ in HCC. We further proved that TIF1γ suppressed cyotstasis‐related TGF‐β/Smad downstream c‐myc down‐regulation, as well as p21/cip1 and p15/ink4b up‐regulation in early‐stage HCC. Meanwhile, TGF‐β inducible epithelial‐mesenchymal transition and TGF‐β/Smad downstream metastatic cascades, including phosphatase and tensin homolog deleted on chromosome ten down‐regulation, chemokine (CXC motif) receptor 4 and matrix metalloproteinase 1 induction, and epidermal growth factor receptor– and protein kinase B–signaling transactivation, were inhibited by TIF1γ. In addition, we found that the down‐regulation of TIF1γ in HCC was caused by hypermethylation of CpG islands in the TIF1γ promoter, and demonstrated that the combination of TIF1γ and phosphorylated Smad2 was a more powerful predictor of poor prognosis. Conclusion: TIF1γ regulates tumor growth and metastasis through inhibition of TGF‐β/Smad signaling and may serve as a novel prognostic biomarker in HCC. (Hepatology 2014;60:1620–1636)

Activin A induces growth arrest through a SMAD- dependent pathway in hepatic progenitor cells.

BackgroundActivin A, an important member of transforming growth factor-β superfamily, is reported to inhibit proliferation of mature hepatocyte. However, the effect of activin A on growth of hepatic progenitor cells is not fully understood. To that end, we attempted to evaluate the potential role of activin A in the regulation of hepatic progenitor cell proliferation.ResultsUsing the 2-acetaminofluorene/partial hepatectomy model, activin A expression decreased immediately after partial hepatectomy and then increased from the 9th to 15th day post surgery, which is associated with the attenuation of oval cell proliferation. Activin A inhibited oval cell line LE6 growth via activating the SMAD signaling pathway, which manifested as the phosphorylation of SMAD2/3, the inhibition of Rb phosphorylation, the suppression of cyclinD1 and cyclinE, and the promotion of p21WAF1/Cip1 and p15INK4B expression. Treatment with activin A antagonist follistatin or blocking SMAD signaling could diminish the anti-proliferative effect of activin A. By contrast, inhibition of the MAPK pathway did not contribute to this effect. Antagonizing activin A activity by follistatin administration enhanced oval cell proliferation in the 2-acetylaminofluorene/partial hepatectomy model.ConclusionActivin A, acting through the SMAD pathway, negatively regulates the proliferation of hepatic progenitor cells.

MicroRNA-630 suppresses tumor metastasis through the TGF-β- miR-630-Slug signaling pathway and correlates inversely with poor prognosis in hepatocellular carcinoma

The epithelial-mesenchymal transition (EMT) is the key process that drives tumor metastasis. Accumulating evidence suggests that the deregulation of some microRNAs (miRNAs), is implicated in this process. Here, we highlight the function and molecular mechanism of miR-630 and its potential clinical application in hepatocellular carcinoma (HCC). First, we identified the clinical relevance of miR-630 expression in a screen of 97 HCC patient tissues. Patients with low miR-630 expression had higher recurrence rates and shorter overall survival than those with high miR-630 expression. Functional studies demonstrated the overexpression of miR-630 in HCC cells attenuated the EMT phenotype in vitro. Conversely, inhibition of miR-630 promoted EMT in HCC cells. Mechanistically, our data revealed that miR-630 suppressed EMT by targeting Slug. Knockdown of Slug expression reversed miR-630 inhibitor-mediated EMT progression. Furthermore, we found that the TGF-β-Erk/SP1 and JNK/c-Jun signaling pathways repressed miR-630 transcription through occupying transcription factor binding sites. Ectopic expression of miR-630 restored the TGF-β-activated EMT process. Taken together, these findings demonstrate, in HCC cells, miR-630 exerts its tumor-suppressor functions through the TGF-β-miR-630-Slug axis and provides a potential prognostic predictor for HCC patients.

Smad6 suppresses the growth and self-renewal of hepatic progenitor cells.

Activation of hepatic progenitor cells (HPCs) is commonly observed in chronic liver disease and Wnt/β‐catenin signaling plays a crucial role in the expansion of HPCs. However, the molecular mechanisms that regulate the activation of Wnt/β‐catenin signaling in the liver, especially in HPCs, remain largely elusive. Here, we reported that ectopic expression of Smad6 suppressed the proliferation and self‐renewal of WB‐F344 cells, a HPC cell line. Mechanistically, we found that Smad6 inhibited Wnt/β‐catenin signaling through promoting the interaction of C‐terminal binding protein (CtBP) with β‐catenin/T‐cell factor (TCF) complex to inhibit β‐catenin mediated transcriptional activation in WB‐F344 cells. We used siRNA targeting β‐catenin to demonstrate that Wnt/β‐catenin signaling was required for the proliferation and self‐renewal of HPCs. Taken together, these results suggest that Smad6 is a regulatory molecule which regulates the proliferation, self‐renewal and Wnt/β‐catenin signaling in HPCs. J. Cell. Physiol. 229: 651–660, 2014.

Activin A-Smad Signaling Mediates Connective Tissue Growth Factor Synthesis in Liver Progenitor Cells

Liver progenitor cells (LPCs) are activated in chronic liver damage and may contribute to liver fibrosis. Our previous investigation reported that LPCs produced connective tissue growth factor (CTGF/CCN2), an inducer of liver fibrosis, yet the regulatory mechanism of the production of CTGF/CCN2 in LPCs remains elusive. In this study, we report that Activin A is an inducer of CTGF/CCN2 in LPCs. Here we show that expression of both Activin A and CTGF/CCN2 were upregulated in the cirrhotic liver, and the expression of Activin A positively correlates with that of CTGF/CCN2 in liver tissues. We go on to show that Activin A induced de novo synthesis of CTGF/CCN2 in LPC cell lines LE/6 and WB-F344. Furthermore, Activin A contributed to autonomous production of CTGF/CCN2 in liver progenitor cells (LPCs) via activation of the Smad signaling pathway. Smad2, 3 and 4 were all required for this induction. Collectively, these results provide evidence for the fibrotic role of LPCs in the liver and suggest that the Activin A-Smad-CTGF/CCN2 signaling in LPCs may be a therapeutic target of liver fibrosis.

Autocrine transforming growth factor-β/activin A-Smad signaling induces hepatic progenitor cells undergoing partial epithelial-mesenchymal transition states

Hepatic progenitor cells (HPCs) are a subpopulation of cells which was usually expanded in chronic liver injury and are contributed to liver regeneration through differentiating into hepatocytes and cholangiocytes. Epithelial-mesenchymal transition is a dynamic process which is important for the progression of liver fibrosis and cancer initiation. This study demonstrated that LE/6 and WB-F344 cells, both of which were HPC derived cell lines, were undergoing partial epithelial-mesenchymal transition states, which was indicated by the co-expression of epithelial markers (E-cadherin and zona occludin 1), and mesenchymal markers (vimentin, fibronectin, collagen 1and α-SMA). Furthermore, autocrine TGF-β and activin A signaling contributed to the maintenance of partial EMT in HPCs. In addition, Smad signaling, a classic downstream signaling cascade of both TGF-β and activin A, also participated in the partial EMT. These findings revealed the existence of partial EMT states in HPCs and confirmed some partial EMT related autocrine signaling cascades, and may help to further the understanding and explore the functional role of HPCs in the process of hepatic fibrosis and liver cancer initiation.

Endovascular Treatment of Behcet Disease With Recurrent Infrainguinal Arterial Pseudoaneurysms: A Case Report and Literature Review.

AbstractAneurysm or pseudoaneurysm formation is one of the vascular complications of Behcet disease. At present, the optimal treatment for the disease has not been established.The authors report a case of vasculo-Behcet disease (v-BD) with recurrent pseudoaneurysms in the left infrainguinal arteries (common femoral artery, superficial femoral artery, and popliteal artery), as well as thrombosis in the popliteal vein and posterior tibial vein. The patient underwent 3 rounds of surgery, but developed a new pseudoaneurysm several months after each surgery. Eventually, the patient was successfully treated with a combination of endovascular repair, using a fully covered stent graft, and prednisone. The pseudoaneurysm regressed without recurrence for more than 1 year.For v-BD, treatment with immunosuppressive therapy alone may not be sufficient to prevent the recurrence of pseudoaneurysms. For the endovascular treatment of pseudoaneurysms affecting the infrainguinal arteries in v-BD, a fully covered stent graft without oversizing is essential to prevent the recurrence of pseudoaneurysms.

Intraoperative ultrasonography of robot-assisted laparoscopic hepatectomy: initial experiences from 110 consecutive cases

BackgroundTo evaluate the safety and efficacy of IOUS in robotic liver surgery and propose a standard protocol of IOUS for safe robot-assisted hepatectomy.MethodsBetween February 2015 and December 2016, liver resection was performed in 110 patients with robotic approach in Tongji Hospital. In these patients, IOUS was routinely performed. All data about demographic, surgical procedure, postoperative course were collected prospectively and analyzed.ResultsA four steps IOUS protocol in robotic liver surgery was proposed, including exploration, verification, guidance, and confirmation. A total of 11 additional lesions in 11 patients were detected and 7 patients accepted strategic surgical modification. No patient suffered from any single or multiple organ dysfunctions, and there were no mortalities observed.ConclusionIOUS is indispensable to understand lesions and vessels in robotic liver surgery. A four-step standard protocol of IOUS is essential for safe robot-assisted hepatectomy.

CD2‐associated Protein Contributes to Hepatitis C Virus Propagation and Steatosis by Disrupting Insulin Signaling

Chronic hepatitis C virus (HCV) infection can result in steatosis, a condition displaying aberrant accumulation of neutral lipid vesicles, the component of lipid droplets (LDs), which are essential for HCV assembly. However, the interplay between HCV infection and steatosis remains unclear. Here, we show that HCV‐infected cells have higher levels of CD2‐associated protein (CD2AP), which plays two distinct, yet tightly linked, roles in HCV pathogenesis: Elevated CD2AP binds to nonstructural protein 5A (NS5A) and participates in the transport of NS5A to LDs to facilitate viral assembly; Up‐regulated CD2AP also interacts with casitas B‐lineage lymphoma (b) (Cbl/Cbl‐b) E3 ligases to degrade insulin receptor substrate 1 (IRS1), which, in turn, disrupts insulin signaling and increases LD accumulation through the IRS1/protein kinase B (Akt)/adenosine monophosphate‐activated protein kinase (AMPK)/hormone‐sensitive lipase (HSL) signaling axis to accommodate viral assembly. In the HCV‐infected mouse model, CD2AP expression is up‐regulated during the chronic infection stage and this up‐regulation correlates well with liver steatosis. Importantly, CD2AP up‐regulation was also detected in HCV‐infected human liver biopsies showing steatosis compared to non‐HCV‐infected controls. Conclusion: CD2AP is indicated as a protein up‐regulated by HCV infection, which, in turn, stimulates HCV propagation and steatosis by disrupting insulin signaling; targeting CD2AP may offer an opportunity for alleviating HCV infection and its associated liver pathology. (Hepatology 2018;XX:XXX‐XXX.)