Mesothelial cells (MCs) cover the surface of visceral organs and the parietal walls of cavities, and they synthesize lubricating fluids to create a slippery surface that facilitates movement between organs without friction. Recent studies have indicated that MCs play active roles in liver development, fibrosis, and regeneration. During liver development, the mesoderm produces MCs that form a single epithelial layer of the mesothelium. MCs exhibit an intermediate phenotype between epithelial cells and mesenchymal cells. Lineage tracing studies have indicated that during liver development, MCs act as mesenchymal progenitor cells that produce hepatic stellate cells, fibroblasts around blood vessels, and smooth muscle cells. Upon liver injury, MCs migrate inward from the liver surface and produce hepatic stellate cells or myofibroblast depending on the etiology, suggesting that MCs are the source of myofibroblasts in capsular fibrosis. Similar to the activation of hepatic stellate cells, transforming growth factor β induces the conversion of MCs into myofibroblasts. Further elucidation of the biological and molecular changes involved in MC activation and fibrogenesis will contribute to the development of novel approaches for the prevention and therapy of liver fibrosis.
Epithelial Cells/*physiology ; Epithelium/metabolism ; Hepatic Stellate Cells/*physiology ; Humans ; Liver/*cytology/injuries/*physiology ; Liver Cirrhosis/etiology/prevention & control ; Liver Regeneration/*physiology ; Mesenchymal Stromal Cells/physiology ; Myofibroblasts/physiology

Infection of schistosomiasis japonica may eventually lead to liver fibrosis, and no effective antifibrotic therapies are available but liver transplantation. Hedgehog (HH) signaling pathway has been involved in the process and is a promising target for treating liver fibrosis. This study aimed to explore the effects of pentoxifylline (PTX) on liver fibrosis induced by schistosoma japonicum infection by inhibiting the HH signaling pathway. Phorbol12-myristate13-acetate (PMA) was used to induce human acute mononuclear leukemia cells THP-1 to differentiate into macrophages. The THP-1-derived macrophages were stimulated by soluble egg antigen (SEA), and the culture supernatants were collected for detection of activation of macrophages. Cell Counting Kit-8 (CCK-8) was used to detect the cytotoxicity of the culture supernatant and PTX on the LX-2 cells. The LX-2 cells were administered with activated culture supernatant from macrophages and(or) PTX to detect the transforming growth factor-β gene expression. The mRNA expression of shh and gli-1, key parts in HH signaling pathway, was detected. The mRNA expression of shh and gli-1 was increased in LX-2 cells treated with activated macrophages-derived culture supernatant, suggesting HH signaling pathway may play a key role in the activation process of hepatic stellate cells (HSCs). The expression of these genes decreased in LX-2 cells co-cultured with both activated macrophages-derived culture supernatant and PTX, indicating PTX could suppress the activation process of HSCs. In conclusion, these data provide evidence that PTX prevents liver fibrogenesis in vitro by the suppression of HH signaling pathway.
Animals ; Antigens, Helminth ; isolation & purification ; pharmacology ; Cell Culture Techniques ; Cell Differentiation ; drug effects ; Cell Line ; Culture Media, Conditioned ; chemistry ; pharmacology ; Gene Expression Regulation ; Hedgehog Proteins ; agonists ; antagonists & inhibitors ; genetics ; immunology ; Hepatic Stellate Cells ; cytology ; drug effects ; metabolism ; Humans ; Liver Cirrhosis ; metabolism ; parasitology ; prevention & control ; Macrophage Activation ; drug effects ; Macrophages ; cytology ; drug effects ; immunology ; Models, Biological ; Monocytes ; cytology ; drug effects ; metabolism ; Pentoxifylline ; pharmacology ; Phosphodiesterase Inhibitors ; pharmacology ; RNA, Messenger ; genetics ; immunology ; Schistosoma japonicum ; chemistry ; Signal Transduction ; Tetradecanoylphorbol Acetate ; pharmacology ; Zinc Finger Protein GLI1 ; genetics ; immunology ; Zygote ; chemistry

OBJECTIVETo study the effect of total flavanones of Sedum sarmentosum (SSTF) on the apoptosis of rat hepatic stellate cells (HSC-T6) and its mechanism.

METHODDifferent concentrations of SSTF and HSC-T6 cells were co-cultured for different period of time. The MTT assay was used to detect the inhibitory effect of SSTF on the proliferation of HSC-T6 cells. The flow cytometry Annexin-V/PI double staining method was adopted to detect SSTF's effect on HSC-T6 cell apoptosis. Western blotting and Real-time PCR methods were applied to observe the effect on the protein and mRNA expressions of apoptosis-related cytokines Bcl-2, Bax and Caspase-3.

RESULTSSTF significantly inhibited HSC-T6 cell proliferation and induced cell apoptosis in a dose and time dependent manner. According to Western blotting result, SSTF promoted apoptosis by inhibiting Bcl-2, Bax and promoting the protein expression of Caspase-3; according to a further Real-time PCR study, Bcl-2 mRNA levels can inhibit Bcl-2 and promote Bax and Caspase-3 expressions.

CONCLUSIONSSTF has the effect of promoting the apoptosis of HSC-T6 mainly by inhibiting Bcl-2 and promoting protein and mRNA expressions of Bax and caspase-3.

Animals ; Apoptosis ; drug effects ; Caspase 3 ; genetics ; metabolism ; Cell Line ; Cell Proliferation ; drug effects ; Drugs, Chinese Herbal ; pharmacology ; Flavanones ; pharmacology ; Hepatic Stellate Cells ; cytology ; drug effects ; metabolism ; Proto-Oncogene Proteins c-bcl-2 ; genetics ; metabolism ; Rats ; Sedum ; chemistry

Liver fibrosis is an important health problem that can further progress into cirrhosis or liver cancer, and result in significant morbidity and mortality. Inhibiting proliferation and inducing apoptosis of hepatic stellate cells (HSCs) may be the key point to reverse liver fibrosis. At present, anti-fibrosis drugs are rare. Kinetin is a type of plant-derived cytokinin which has been reported to control differentiation and induce apoptosis of human cells. In this study, the HSCs were incubated with different concentrations of kinetin. The proliferation of rat HSCs was measured by MTT assay, cell cycle and apoptosis were analyzed by flow cytometry, and the apoptosis was examined by TUNEL method. The expression of Bcl-2 and Bax proteins was detected by immunocytochemistry staining. It was found that kinetin could markedly inhibit proliferation of HSCs. In a concentration range of 2 to 8 μg/mL, the inhibitory effects of kinetin on proliferation of HSCs were increased with the increased concentration and the extension of time (P < 0.01). Flow cytometry indicated that kinetin could inhibit the DNA synthesis from G0/G1 to S phase in a dose-dependent manner (P < 0.01). The apoptosis rates of the HSCs treated with 8, 4 and 2 μg/mL kinetin (25.62% ± 2.21%, 15.31% ± 1.9% and 6.18% ± 1.23%, respectively) were increased significantly compared with the control group (3.81% ± 0.93%) (P < 0.01). All the DNA frequency histogram in kinetin-treated groups showed obvious hypodiploid peak (sub-G1 peak), and with the increase of kinetin concentrations, the apoptosis rate of HSCs also showed a trend of increase. It was also found that kinetin could down-regulate the expression of Bcl-2, and up-regulate the expression of Bax, leading to the decreased ratio of Bcl-2/Bax significantly. The kinetin-induced apoptosis of HSCs was positively correlated with the expression of Bax, and negatively with the expression of Bcl-2. It was concluded that kinetin can inhibit activation and proliferation of HSCs by interrupting the cell cycle at G1/S restriction point and inducing apoptosis of HSCs via reducing the ratio of Bcl-2/Bax.
Animals ; Apoptosis ; drug effects ; Cell Line, Transformed ; Cell Proliferation ; drug effects ; Dose-Response Relationship, Drug ; G1 Phase Cell Cycle Checkpoints ; drug effects ; genetics ; Gene Expression Regulation ; Growth Inhibitors ; pharmacology ; Hepatic Stellate Cells ; cytology ; drug effects ; metabolism ; Kinetin ; pharmacology ; Proto-Oncogene Proteins c-bcl-2 ; antagonists & inhibitors ; genetics ; metabolism ; Rats ; Signal Transduction ; bcl-2-Associated X Protein ; agonists ; genetics ; metabolism

To observe the effect of calycosin on the proliferation and activation of primary hepatic stellate cells (HSCs) in rats, and prove calycosin shows the effects through peroxisome proliferator-activated receptor γ(PPARγ) and farnesoid X receptor (FXR). The results indicated that calycosin could inhibit HSC proliferation and expressions of activation marker smooth muscle actin-α and type I collagen. With the increase in HSC activation time, FXR expression reduced, but with no notable impact from calycosin. Calycosin could up-regulate PPARγ expression and its nuclear transition in a concentration-dependent manner. Its prohibitory effect on HSC activation could be blocked by PPARγ antagonist. In conclusion, calycosin could inhibit HSC activation and proliferation, which may be related with the up-regulation of PPARγ signal pathway.
Animals ; Cell Proliferation ; drug effects ; Cells, Cultured ; Drugs, Chinese Herbal ; pharmacology ; Hepatic Stellate Cells ; cytology ; drug effects ; metabolism ; Isoflavones ; pharmacology ; Male ; PPAR gamma ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley ; Receptors, Cytoplasmic and Nuclear ; genetics ; metabolism ; Up-Regulation ; drug effects

BACKGROUND/AIMS: Therapies involving bone-marrow-derived mesenchymal stem cells (BM-MSCs) have considerable potential in the management of hepatic disease. BM-MSCs have been investigated in regenerative medicine due to their ability to secrete various growth factors and cytokines that regress hepatic fibrosis and enhance hepatocyte functionality. The aim of this study was to determine the antifibrosis effect of BM-MSCs on activated hepatic stellate cells (HSCs) and the mechanism underlying how BM-MSCs modulate the function of activated HSCs. METHODS: We used HSCs in both direct and indirect co-culture systems with BM-MSCs to evaluate the antifibrosis effect of BM-MSCs. The cell viability and apoptosis were evaluated by a direct co-culture system of activated HSCs with BM-MSCs. The activations of both HSCs alone and HSCs with BM-MSCs in the direct co-culture system were observed by immunocytochemistry for alpha-smooth muscle actin (alpha-SMA). The levels of growth factors and cytokines were evaluated by an indirect co-culture system of activated HSCs with BM-MSCs. RESULTS: The BM-MSCs in the direct co-culture system significantly decreased the production of alpha-SMA and the viability of activated HSCs, whereas they induced the apoptosis of activated HSCs. The BM-MSCs in the indirect co-culture system decreased the production of transforming growth factor-beta1 and interleukin (IL)-6, whereas they increased the production of hepatocyte growth factor and IL-10. These results confirmed that the juxtacrine and paracrine effects of BM-MSCs can inhibit the proliferative, fibrogenic function of activated HSCs and have the potential to reverse the fibrotic process by inhibiting the production of alpha-SMA and inducing the apoptosis of HSCs. CONCLUSIONS: These results have demonstrated that BM-MSCs may exert an antifibrosis effect by modulating the function of activated HSCs.
Apoptosis ; Bone Marrow Cells/*cytology ; Cell Differentiation ; Coculture Techniques ; Hepatic Stellate Cells/*cytology/metabolism ; Hepatocyte Growth Factor/metabolism ; Humans ; Immunophenotyping ; Interleukin-10/metabolism ; Interleukin-6/metabolism ; Liver Cirrhosis ; Mesenchymal Stromal Cells/*cytology/metabolism ; Transforming Growth Factor beta1/metabolism

Hepatic stellate cells (HSCs), also called Ito cells or lipocytes, are one of inherent liver nonparenchymal cell types located in the Dissé space between hepatocytes and sinusoidal endothelial cells, and account for up to 50%-80% of vitamin A in the form of lipid drops. The methods of primary HSCs isolation mainly focus on density gradient centrifugation combined with centrifugal elutriation, side scatter-activated cell sorting, UV-excited autofluorescence or antibody-based flow cytometry, etc., and will provide solid foundation for the research on physiological and pathological HSCs function. The research of this vitamin A-storing cells has developed and expanded vigorously. In physiological conditions, HSCs are quiescent and play pivotal roles in the synthesis of extracellular matrix (ECM) to maintain its stability with broad uptake and storage of vitamin A, and also regulate liver regeneration. But in pathological conditions, HSCs are activated by constant stimulations or liver injury, then with activated proliferation, reduced lipid drops, and increased ECM synthesis. Morphology of these cells also changes from the star-shaped stellate cells to that of fibroblasts or myofibroblasts with obvious contractibility and secretion of cytokines and chemokines including a variety of proinflammatory factors and adhesion molecules, suggesting that the activation of HSCs is one of the key events in the development of liver fibrosis. Study on the isolation and function of HSCs is always one of the hot topics for liver biology. In this review, we systematically summarize and discuss the recent advances in our understanding of the isolation methods and improvements of HSCs, and functional research of HSCs biology in health and disease, as well as potential directions.
Extracellular Matrix ; metabolism ; Hepatic Stellate Cells ; cytology ; Humans ; Liver ; cytology ; Regeneration ; Vitamin A ; metabolism

OBJECTIVETo investigate the effects of salvianolic acid B (Sal B) on endothelin-1 (ET1)-induced contraction and cytoskeleton reorganization of rat hepatic stellate cells (HSCs).

METHODSHSCs were collected from Sprague-Dawley rats by in situ perfusion with pronase E and isolated by density-gradient centrifugation with Nycodenz. Cells were treated with ET-1, with or without Sal B or Y-27632 (a specific inhibitor of rho-associated protein kinases) pretreatment. HSC contraction was evaluated by collagen gel contraction assay. Cytoskeletal reorganization in response to ET-1 was evaluated by detecting changes in phosphorylation of myosin light chain 2 (MLC2) using glycerol-urea PAGE and the Odyssey Infrared Imaging System. Changes in actin stress fiber polymerization were detected by FITC-labeled phalloidin. Differences between the various cell treatment/pretreatment groups were statistically analyzed.

RESULTSCompared to the untreated control cells, the lattice area of ET-1-treated cells showed significant shrinkage (76.89% ± 3.84% vs. 37.10% ± 5.10%; P less than 0.01). Pretreatment with 105 M Sal B or 105 M Y-27632 significantly reduced ET-1-induced contraction (67.01% ± 4.14% and 77.28% ± 2.00%, respectively; bothP less than 0.01 vs. the ET-1-treated cells). The untreated control cells showed a basal MLC2 phosphorylation of (0.35 ± 0.05) mol PO4/mol MLC2. In contrast, ET-1 treatment elicited a rapid and sustained MLC2 phosphorylation, which was (0.87 ± 0.04) mol PO₄/mol MLC2 at 5 min post-treatment and with the maximal level of (0.96 ± 0.04) mol PO₄/mol MLC2 detected at 30 min post-treatment. The Sal B pretreatment led to a significant decrease in ET-1-induced MLC2 phosphorylation (by 63.1%) and an obvious disassembly of actin stress fibers.

CONCLUSIONSal B effectively inhibits ET-1-induced rat HSC contraction, through its suppressive effects on MLC2 phosphorylation and promotion of the disassembly of actin stress fibers.

Actins ; metabolism ; Animals ; Benzofurans ; pharmacology ; Cardiac Myosins ; metabolism ; Cell Shape ; Cells, Cultured ; Cytoskeleton ; drug effects ; Endothelin-1 ; pharmacology ; Hepatic Stellate Cells ; cytology ; drug effects ; Male ; Myosin Light Chains ; metabolism ; Phosphorylation ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo explore the role of the Rho pathway in the hepatocyte growth factor (HGF) paracrine signal-mediated bone marrow-derived mesenchymal stem cell (BMSC) promotion of apoptosis of hepatic stellate cells (HSCs).

METHODSA BMSC-HSC co-culture system was established using plates with transwell inserts. Dynamic changes in response to pretreatment with the c-met blocker PHA665752 and the Rho pathway inhibitor Y-27632 were observed under an inverted phase contrast microscope at 24, 48 and 72 h of culture. Optimal intervention concentrations of Y-27632 and PHA665752 were determined by MTT assay. Expression of alpha-smooth muscle actin in HSCs was evaluated by immunohistochemistry, and the apoptosis rate of HSCs was measured by Annexin-V-FITC/propidium iodide. RhoA protein and mRNA levels were measured by western blot and quantitative real-time PCR respectively. Concentrations of HGF and hepatocyte growth factor activator (HGFA) were quantified by enzyme-linked immunosorbent assay. Between-group differences were evaluated by one-way ANOVA with P less than 0.05 indicating significance.

RESULTSThe apoptosis rates of HSCs gradually and steadily increased in a time-dependent manner. The apoptosis rate of the PHA665752 pretreated group was lowest and that of the Y-27632 pretreated group was highest, with the most robust difference occurring at the 72 h time point (P less than 0.05). The mRNA and protein expression levels of RhoA decreased in a time-dependent manner in the Y-27632 pretreated group (all time points, P less than 0.05) but the expression levels increased in a time-dependent manner in the PHA665752 pretreated group (all time points, P less than 0.05). For both the PHA665752 and the Y-27632 pretreated groups, the concentration of HGF decreased in a time-dependent manner, but the concentrations in both remained significantly higher than that in the control group at all time points examined (P less than 0.05). The concentration of HGFA increased in a time-dependent manner, and the PHA665752 pretreated group showed significantly higher levels than any of the other groups at all time points examined (P less than 0.01).

CONCLUSIONBMSC promotes HSC apoptosis in a co-culture system by activating HGF and down-regulating the RhoA signaling pathway.

Actins ; metabolism ; Animals ; Apoptosis ; Bone Marrow Cells ; cytology ; Cell Line ; Cells, Cultured ; Coculture Techniques ; Hepatic Stellate Cells ; cytology ; Hepatocyte Growth Factor ; secretion ; Male ; Mesenchymal Stromal Cells ; cytology ; Rats ; Rats, Sprague-Dawley ; Signal Transduction

OBJECTIVETo construct a single-chain human anti-EGFR antibody (scFv) and truncated protamine (tP) fusion protein, ScFv/tP, carrying small interfering (si)RNA directed against the heat shock protein Hsp47, a collagen-binding glycoprotein, in order to evaluate the role Hsp47 in apoptosis of hepatic stellate cells.

METHODSA single chain of the human variable fragment was obtained by phage display and fused with the tP gene and with or without (negative control) the Hsp47 siRNA sequences. Following expression and purification of the scFv/tP fusion protein and the scFv/tPHsp47 siRNA fusion protein, internalization capabilities were tested in isolated human hepatic stellate cells and the QSG-7701 human hepatocyte cells with visualization by immunofluorescent staining. The DNA binding ability of the fusion proteins were verified by gel shift assay.Following ScFv/tP-Hsp47 siRNA fusion protein transfection into the human hepatic stellate cells, the levels of Hsp47 mRNA and protein expression were tested by RT-PCR and Western blotting; in addition, effects of siRNA-mediated silencing of Hsp47 on cell proliferation and apoptosis were analyzed by the cell counting kit (CCK)-8, flow cytometry and Western blot detection of the apoptosis marker poly (ADP-ribose) polymerase (PARP).

RESULTSIndirect immunofluorescence revealed that the ScFv/tP fusion proteins were internalized into human hepatic stellate cells but not into the QSG-7701 cells.The ScFv/tP-Hsp47 siRNA fusion protein caused reduced expression of Hsp47 mRNA and protein expression in the human hepatic stellate cells, as well as increased the cells' apoptosis remarkably.

CONCLUSIONThe ScFv/tP fusion protein can be used as a transfection reagent to deliver Hsp47 siRNA into hepatic stellate cells and to mediate apoptosis via blockade of Hsp47 expression.

Apoptosis ; Cell Proliferation ; HSP47 Heat-Shock Proteins ; genetics ; Hepatic Stellate Cells ; cytology ; Humans ; Protamines ; metabolism ; RNA, Messenger ; RNA, Small Interfering ; Receptor, Epidermal Growth Factor ; immunology ; Single-Chain Antibodies ; Transfection