scholarly journals Evidence for and against epithelial-to-mesenchymal transition in the liver

2013 ◽  
Vol 305 (12) ◽  
pp. G881-G890 ◽  
Author(s):  
Guanhua Xie ◽  
Anna Mae Diehl
Keyword(s):  
Liver Injury ◽  
Epithelial Cells ◽  
Hepatic Stellate Cells ◽  
Epithelial To Mesenchymal Transition ◽  
Stellate Cell ◽  
Stellate Cells ◽  
Mesenchymal Cells ◽  
Mesenchymal Transition ◽  
Liver Epithelial Cells ◽  
Liver Repair

The outcome of liver injury is determined by the success of repair. Liver repair involves replacement of damaged liver tissue with healthy liver epithelial cells (including both hepatocytes and cholangiocytes) and reconstruction of normal liver structure and function. Current dogma posits that replication of surviving mature hepatocytes and cholangiocytes drives the regeneration of liver epithelium after injury, whereas failure of liver repair commonly leads to fibrosis, a scarring condition in which hepatic stellate cells, the main liver-resident mesenchymal cells, play the major role. The present review discusses other mechanisms that might be responsible for the regeneration of new liver epithelial cells and outgrowth of matrix-producing mesenchymal cells during hepatic injury. This theory proposes that, during liver injury, some epithelial cells undergo epithelial-to-mesenchymal transition (EMT), acquire myofibroblastic phenotypes/features, and contribute to fibrogenesis, whereas certain mesenchymal cells (namely hepatic stellate cells and stellate cell-derived myofibroblasts) undergo mesenchymal-to-epithelial transition (MET), revert to epithelial cells, and ultimately differentiate into either hepatocytes or cholangiocytes. Although this theory is highly controversial, it suggests that the balance between EMT and MET modulates the outcome of liver injury. This review summarizes recent advances that support or refute the concept that certain types of liver cells are capable of phenotype transition (i.e., EMT and MET) during both culture conditions and chronic liver injury.

scholarly journals Proliferation of hepatic stellate cells, mediated by YAP and TAZ, contributes to liver repair and regeneration after liver ischemia-reperfusion injury

2018 ◽  
Vol 314 (4) ◽  
pp. G471-G482 ◽  
Author(s):  
Takanori Konishi ◽  
Rebecca M. Schuster ◽  
Alex B. Lentsch
Keyword(s):  
Cell Proliferation ◽  
Liver Injury ◽  
Hepatic Stellate Cell ◽  
Hepatic Stellate Cells ◽  
Stellate Cell ◽  
Ischemia Reperfusion ◽  
Stellate Cells ◽  
Hepatocyte Proliferation ◽  
Binding Motif ◽  
Liver Repair

Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ) are key regulators of cell proliferation and organ size; however, their physiological contribution after liver injury has not been fully understood. In this study, we sought to determine the role of YAP and TAZ during liver recovery after ischemia-reperfusion (I/R). A murine model of partial (70%) I/R was used to induce liver injury and study the reparative and regenerative response. After liver injury, there was marked activation and proliferation of hepatic stellate cells. The Hippo pathway components, large tumor suppressor 1 (LATS1) and its adapter protein, Mps one binder 1 (MOB1), were inactivated during liver repair, and YAP and TAZ were activated selectively in hepatic stellate cells. Concurrently, the expression of connective tissue growth factor and survivin, both of which are YAP and TAZ target genes, were upregulated. Hepatic stellate cell expansion and concomitant activation of YAP and TAZ occurred only in the injured liver and were not observed in the nonischemic liver. Treatment of mice with verteporfin, an inhibitor of YAP and TAZ, decreased hepatic stellate cell proliferation, survivin, and cardiac ankyrin repeat protein expression. These changes were associated with a significant decrease in hepatocyte proliferation. The data suggest that liver repair and regeneration after I/R injury are dependent on hepatic stellate cell proliferation, which is mediated by YAP and TAZ. NEW & NOTEWORTHY This study is the first to assess the proliferation of hepatic stellate cells (HSCs) after ischemia-reperfusion (I/R) injury and their role in the reparative and regenerative process. Here we show that the Hippo pathway is inactivated after I/R and that Yes-associated protein/transcriptional coactivator with PDZ-binding motif (YAP/TAZ) activation is detected in HSC. HSC proliferation and expansion are prominent during liver recovery after I/R injury. Inhibition of YAP/TAZ activation with verteporfin reduces HSC proliferation and target gene expression and attenuates hepatocyte proliferation.

scholarly journals Hepatic Stellate Cell-Derived Microvesicles Prevent Hepatocytes from Injury Induced by APAP/H2O2

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Renwei Huang ◽  
Qunwen Pan ◽  
Xiaotang Ma ◽  
Yan Wang ◽  
Yaolong Liang ◽  
...  
Keyword(s):  
Liver Injury ◽  
Hepatic Stellate Cells ◽  
Culture Medium ◽  
Caspase 3 ◽  
Cell Function ◽  
Stellate Cell ◽  
Annexin V ◽  
Stellate Cells ◽  
Human Hepatocytes ◽  
Injury Models

Hepatic stellate cells (HSCs), previously described for liver-specific mesenchymal stem cells (MSCs), appear to contribute to liver regeneration. Microvesicles (MVs) are nanoscale membrane fragments, which can regulate target cell function by transferring contents from their parent cells. The aim of this study was to investigate the effect of HSC-derived MVs on xenobiotic-induced liver injury. Rat and human hepatocytes, BRL-3A and HL-7702, were used to build hepatocytes injury models by n-acetyl-p-aminophenol n-(APAP) or H2O2treatment. MVs were prepared from human and rat HSCs, LX-2, and HST-T6 and, respectively, added to injured BRL-3A and HL-7702 hepatocytes. MTT assay was utilized to determine cell proliferation. Cell apoptosis was analyzed by flow cytometry and hoechst33258 staining. Western blot was used for analyzing the expression of activated caspase-3. Liver injury indicators, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH) in culture medium were also assessed. Results showed that (1) HSC-MVs derived from LX-2 and HST-T6 were positive to CD90 and annexin V surface markers; (2) HSC-MVs dose-dependently improved the viability of hepatocytes in both injury models; (3) HSC-MVs dose-dependently inhibited the APAP/H2O2induced hepatocytes apoptosis and activated caspase-3 expression and leakage of LDH, ALT, and AST. Our results demonstrate that HSC-derived MVs protect hepatocytes from toxicant-induced injury.

scholarly journals Fuzheng Huayu Recipe Ameliorates Liver Fibrosis by Restoring Balance between Epithelial-to-Mesenchymal Transition and Mesenchymal-to-Epithelial Transition in Hepatic Stellate Cells

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Qin Pan ◽  
Yu-Qin Wang ◽  
Guang-Ming Li ◽  
Xiao-Yan Duan ◽  
Jian-Gao Fan
Keyword(s):  
Liver Fibrosis ◽  
P38 Mapk ◽  
Hepatic Stellate Cells ◽  
Epithelial To Mesenchymal Transition ◽  
Stellate Cells ◽  
Cordyceps Sinensis ◽  
Dependent Manner ◽  
Radix Salviae Miltiorrhizae ◽  
Mesenchymal Transition ◽  
Mesenchymal To Epithelial Transition

Activation of hepatic stellate cells (HSCs) depending on epithelial-to-mesenchymal transition (EMT) reflects the key event of liver fibrosis. Contrastively, mesenchymal-to-epithelial transition (MET) of HSCs facilitates the fibrosis resolution. Here we investigated the effect of Fuzheng Huayu (FZHY) recipe, a Chinese herbal decoction made ofRadix Salviae Miltiorrhizae,Semen Persicae,Cordyceps sinensis,Pollen Pini, andGynostemma pentaphyllum, on liver fibrosis concerning the balance of EMT and MET in HSCs. In contrast to the increased TGF-β1/BMP-7 ratio in activated HSCs, FZHY administration induced significant upregulation of BMP-7 and downregulation of TGF-β1at both transcription and translation levels. Restoration of TGF-β1/BMP-7 ratio inhibited the expression of p38 MAPK and phosphorylated p38 MAPK, resulting in the reversal of epithelial-to-mesenchymal transition (EMT) to mesenchymal-to-epithelial transition (MET) as characterized by the abolishment of EMT markers (α-SMA and desmin) and reoccurrence of MET marker (E-cadherin).In vivotreatment of FZHY recipe also demonstrated the statistical reduction of activated HSCs with EMT phenotype, which attenuated the carbon tetrachloride- (CCl4-) induced liver fibrosis in a dose-dependent manner. These findings may highlight a novel antifibrotic role of FZHY recipe on the basis of rebalancing EMT and MET in HSCs.

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