Hepatic Stellate Cells ; metabolism ; Humans ; Signal Transduction

Hepatic Stellate Cells ; metabolism ; Humans ; Signal Transduction

Hepatic Stellate Cells ; Humans ; Liver Cirrhosis ; diagnosis ; metabolism ; Signal Transduction

The lipids present in hepatic stellate cells (HSCs) lipid droplets include retinyl ester, triglyceride, cholesteryl ester, cholesterol, phospholipids and free fatty acids. Activation of HSCs is crucial to the development of fibrosis in liver disease. During activation, HSCs transform into myofibroblasts with concomitant loss of their lipid droplets and production of excessive extracellular matrix. Release of lipid droplets containing retinyl esters and triglyceride is a defining feature of activated HSCs. Accumulating evidence supports the proposal that recovering the accumulation of lipids would inhibit the activation of HSCs. In healthy liver, quiescent HSCs store 80% of total liver retinols and release them depending on the extracellular retinol status. However, in injured liver activated HSCs lose their retinols and produce a considerable amount of extracellular matrix, subsequently leading to liver fibrosis. Further findings prove that lipid metabolism of HSCs is closely associated with its activation, yet relationship between activated HSCs and the lipid metabolism has remained mysterious.
Animals ; Cholesterol ; metabolism ; Hepatic Stellate Cells ; physiology ; Humans ; Lipid Metabolism ; Triglycerides ; metabolism ; Vitamin A ; metabolism

Hepatic Stellate Cells ; metabolism ; Humans ; Liver Cirrhosis ; metabolism ; PPAR gamma ; metabolism

OBJECTIVETo investigate the potential therapeutic properties of the endogenous cannabinoid N-arachidonic acid aminoethanols (anandamide, AEA) in liver fibrosis by observing its affects on proliferation of and expression of phosphorylated-Erk (pErk) in primary hepatic stellate cells (HSCs) from a mouse model of schistosome-induced liver fibrosis.

METHODSThe schistosome-induced liver fibrosis model was established by attaching cercaria to the skin on the ventral side of the mouse and allowing infection to occur via direct penetration. Six weeks later, the model was confirmed by pathological analysis of liver, with Masson trichrome staining showing collagen fiber deposition around the blood vessels and hematoxylin-eosin staining showing eosinophilic granuloma formation. Primary HSCs were isolated by discontinuous density gradient centrifugation, confirmed by immunofluorescence detection of double-staining for a-smooth muscle actin and desmin (95% purity), and cultured in the presence of absence of various concentrations of AEA. Proliferative ability was evaluated by MTT assay and the expression of pErk was observed by Western blotting.

RESULTSAEA treatment inhibited the proliferation of the primary HSCs in a concentration-dependent manner (AEA: 5 mumol/L, inhibition: 7.68%; 10 mumol/L, 11.65%; 20 mumol/L, 14.70%; 40 mumol/L, 15.07%; 60 mumol/L, 18.18%; 80 mumol/L, 20.26%; 100 mumol/L, 20.17%; 120 mumol/L, 29.24%). AEA treatment increased pERK expression in both a concentration-dependent manner (AEA: 20 mumol/L, average gray value: 39.90+/-4.61; 60 mumol/L, 43.45+/-0.91; 120 mumol/L, 52.91+/-1.97; vs. negative control, all P less than 0.05) and a time-dependent manner (time: 15 min, average gray value: 85.05+/-15.80; 30 min, 103.41+/-11.89; 1 h, 118.02+/-12.24; 3 h, 109.17+/-15.69; 6 h, 100.86+/-10.55; 12 h, 71.70+/-12.87; 24 h, 34.62+/-14.85; 48 h, 22.84+/-11.73; vs. negative control, all except 48 h had P less than 0.05).

CONCLUSIONAEA can suppress the proliferative capacity of primary HSCs from schistosome-induced fibrotic livers through activation of the Erk signaling pathway.

OBJECTIVETo investigate the effects of exogenous TGF-β3 on the expression of endogenous TGF-b3 in hepatic stellate cell (HSC).

METHODSHSCs were cultured and divided into two groups: TGF-β3 group and blank control group, the cells of TGF-β3 group were exposed to TGF-b3 (10 ng/ml), whereas the blank control group was not treated. The cells were incubated in the presence of exogenous TGF-β3 and then (1) were harvested at 0h, 1h, 2h, 4h, 12h, 24h, and real time PCR was performed to detect the mRNA expression of endogenous TGF-β3. (2) The cells were collected at 0h, 1h, 6h, 12h, and western-blot was used to detect the protein synthesis of endogenous TGF-β3 in HSC; (3) The cell culture supernatant was harvested at 0h, 1h, 2h, 4h, 8h, 14h, 24h, and ELISA was performed to measure the total protein of extracellular TGF-β3; HSCs were treated with TGF-β3 (10 ng/ml) for 2h. The cells were then incubated in serum-free medium and the cell culture supernatant was harvested at 2.25h, 2.5h, 3h, 4h, 6h, 10h and 14h. ELISA was used to detect the extracellular secret ion of endogenous TGF-β3 by HSCs.

RESULTS(1) Exogenous TGF-β3 treatment induced a marked increase in TGF-β3 mRNA expression. By 2h of exogenous TGF-β3 treatment, maximal TGF-β3 mRNA expression levels (2.796 ± 0.518) of 2.74 fold above control values (1.022 ± 0.038) was reached (P < 0.05). Thereafter, TGF-β3 mRNA expression level declined, and the expression level was maintained at level of 1.45-fold for at least 10h and was 1.18-fold above control values by 24h TGF-β3 treatment (P < 0.05); (2) No significant difference about the intracellular protein expression level of endogenous TGF-β3 was found between two groups. (P > 0.05); (3) The total expression level of TGF-β3 reached a peak [(18.931 ± 2.904) ng/ml] at 4h after TGF-β3 treatment (1.89-fold higher than basic TGF-β3 (10 ng/ml). After that, it slowly declined. The expression peak [(0.835 ± 0.027) ng/ml] induction of extracellular secreted TGF-β3 was at 3h (32.12-fold higher than control [(0.026 ± 0.022) ng/ml], (P < 0.05). Thereafter, TGF-β3 slowly decreased after the peak time, and their expressions were still statistically significant as compared to the control (P < 0.05).

CONCLUSIONExogenous TGF-β3 could increase the expression of endogenous TGF-β3 mRNA and extracellular secreted TGF-β3 protein obviously.

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

Adenoviridae ; genetics ; Gene Expression ; Hepatic Stellate Cells ; metabolism ; Humans ; Urokinase-Type Plasminogen Activator ; genetics ; metabolism

Cell Line ; Hepatic Stellate Cells ; drug effects ; metabolism ; Humans ; Interferon-beta ; pharmacology