Curcumin inhibits the activity and induces apoptosis of activated hepatic stellate cell by suppressing autophagy.

Curcumin, a kind of natural compound, has been previously proven to inhibit the autophagy in hepatic stellate cells (HSCs) and induce their apoptosis. However, it is not clear whether the enhanced apoptosis of activated HSCs (aHSCs) caused by curcumin depends on autophagy inhibition. We aim to verify this hypothesis and explore the potential mechanisms in this study. Immortalized human HSC line LX-2 was used as an experimental specimen and pretreated with transforming growth factor ß1(TGF-ß1) for 24 h to activate it before drug application. The levels of autophagy, apoptosis, cell activity, lipid metabolism, and the activity of the PI3K/Akt/mTOR signal pathway were evaluated by multiple methods, such as Western blotting, mcherry-EGFP-LC3B adenoviruses transfection, immunofluorescence, Nile Red staining, flow cytometry among others. Our results showed that rapamycin, an autophagy activator, could partly offset the effects of curcumin on autophagy and apoptosis of LX-2 cells, while 3-Methyladenine (3-MA), an autophagy inhibitor, could enhance these effects. Furthermore, curcumin could promote the activity of the PI3K/Akt/mTOR signal pathway in LX-2 cells, while PI3K inhibitor could partly offset this effect and increase the autophagy level. Overall, we demonstrated that curcumin could inhibit the activity and promote LX-2 cells apoptosis by suppressing autophagy by activating the PI3K/Akt/mTOR signal pathway. In addition, lipid recovery and energy deprivation due to autophagy inhibition may be the exact mechanism by which curcumin attenuates the pro-fibrotic activity of LX-2.

Induction of autophagy and apoptosis by miR-148a through the sonic hedgehog signaling pathway in hepatic stellate cells.

Autophagy is an evolutionarily conserved biological process that is activated in response to stress. Increasing evidence indicate that dysregulated miRNAs significantly contribute to autophagy and are thus implicated in various pathological conditions, including hepatic fibrosis. MiR-148a, a member of the miR-148/152 family, has been found to be downregulated in hepatic fibrosis and human hepatocellular carcinoma. However, the role of miR-148a in the development of hepatic fibrosis remains largely unknown. In this study, we describe the epigenetic regulation of miR-148a and its impact on autophagy in hepatic stellate cells (HSCs), exploring new targets of miR-148a. We found that miR-148a expression was significantly increased under starvation-induced conditions in LX-2 and T-6 cells. In addition, dual-luciferase reporter assays showed that miR-148a suppressed target gene expression by directly interacting with the 3'-untranslated regions (3'-UTRs) of growth arrest-specific gene 1 (Gas1) transcripts. Intriguingly, Gas1, which encodes a Hedgehog surface binding receptor and facilitates the Hedgehog (Hh) signaling pathway, inhibited autophagosome synthesis. Furthermore, we demonstrated a novel function for miR-148a as a potent inducer of autophagy in HSCs. Overexpressing of miR-148a increased autophagic activity, which inhibited proliferation and promoted apoptosis in HSCs. In conclusion, these data support a novel role for miR-148a as a key regulator of autophagy through the Hh signaling pathway, making miR-148a a potential candidate for the development of novel therapeutic strategies.

Curcumin, the main active constituent of turmeric (Curcuma longa L.), induces apoptosis in hepatic stellate cells by modulating the abundance of apoptosis-related growth factors.

In order to elucidate the mechanism of action of curcumin against hepatic fibrosis, cultured rat hepatic stellate cells (HSC) (HSC-T6) were incubated with curcumin for 24 h, after which apoptosis was measured by flow-cytometry. The protein levels of the pro-apoptotic factors Fas and p53b as well as of the anti-apoptotic factor Bcl-2 were monitored by immunocytochemical ABC staining after incubation with curcumin for 24 h. In the case of 20 µM curcumin, not only was the respective apoptosis index increased, but also the abundance of the pro-apoptotic factors Fas and p53 were amplified, whereas that of the anti-apoptotic factor Bcl-2 decreased. All these effects were highly reproducible (P<0.05). Consequently, curcumin has an up-regulating effect on pro-apoptotic factors like Fas and p53 as well as a down-regulating effect of the anti-apoptotic factor Bcl-2, thus inducing apoptosis in HSC.

Transforming growth factor­ß1 reduces apoptosis via autophagy activation in hepatic stellate cells.

Autophagy is a metabolic process that is important in fibrogenesis, in which cellular components are degraded by lysosomal machinery. Transforming growth factor ß1 (TGF­ß1) is a potent fibrogenic cytokine involved in liver fibrosis; however, it remains elusive whether autophagy is regulated by TGF­ß1 in this process. In the present study, the function of TGF­ß1­mediated autophagy in the proliferation and apoptosis of hepatic stellate cells (HSCs) was investigated. A rat HSC cell line (HSC­T6) was incubated with or without TGF­ß1 followed by bafilomycin A1, and microtubule-associated proteins 1A/1B light chain 3 (LC3) small interfering (si)RNA was used to inhibit autophagy in order to assess the association between TGF­ß1 and autophagy. HSC­T6 cell transient transfection was accomplished with a pLVX­AcGFP­N1­rLC3B­encoding plasmid. An MTS assay and flow cytometry were utilized to detect proliferation and apoptosis of HSC­T6 cells. Quantitative polymerase chain reaction, immunofluorescence and western blot analysis were used to detect the presence of activation markers. Proliferation was increased and apoptosis was reduced in HSC­T6 cells treated with TGF­ß1 compared with cells subjected to serum deprivation. However, when HSC­T6 cells were treated with bafilomycin A1 and LC3 siRNA, increased apoptosis and reduced proliferation were observed. In addition, protein and mRNA expression levels of the autophagy marker LC3 were significantly increased. GFP­LC3 punctate markings were more prolific following TGF­ß1 treatment of HSC­T6 cells, indicating that TGF­ß1 may rescue HSC­T6 cells from serum deprivation and reduce apoptosis via autophagy induction. The present study elucidated the possible functions of TGF­ß1­mediated autophagy in the pathological process of liver fibrosis.

[Effects of nerve growth factor on proliferation of hepatic stellate cells].

OBJECTIVE: To determine the effects of nerve growth factor (NGF) on proliferation of hepatic stellate cells (HSCs) and investigate the related molecular mechanism. METHODS: After incubating cultured HSCs for 24 h with different concentrations of NGF (100, 200 or 400 ng/mL), the cell proliferation was observed by XTT colorimetric assay and cell cycle was detected by flow cytometry. Morphological changes in response to a 24 h exposure to 100 ng/mL NGF were observed by transmission electron microscopy. RESULTS: NGF significantly inhibited HSC proliferation (P less than 0.05) in a dose-independent manner. The optical densities of the XTT colorimetric assay were 0.66+/-0.03 for 100 ng/mL NGF, 0.69+/-0.03 for 200 ng/mL NGF, and 0.66+/-0.03 for 400 ng/mL NGF, all of which were significantly lower than that of the control group (0.73+/-0.01; P less than 0.05). All concentrations of NGF led to significantly higher numbers of HSCs in the G2 phase (100 ng/mL: 14.83+/-5.41%, 200 ng/mL: 14.73+/-2.50%, and 400 ng/mL: 14.87+/-2.06%), compared to that detected in the control group (7.47+/-4.39%; P less than 0.05). Twenty-four hours of exposure to 100 ng/mL NGF caused morphological changes indicative of apoptosis. CONCLUSION: NGF inhibits the proliferation of HSCs, possibly by arresting the cells in the G2 phase of the cell cycle. NGF-inhibited cells may also undergo apoptosis.

Percutaneous endoscopic gastrostomy/jejunostomy combined with percutaneous transhepatic biliary drainage in treating malignant biliary obstruction.

OBJECTIVE: To investigate the safety and efficacy of percutaneous endoscopic gastrostomy/jejunostomy (PEG/PEJ) combined with percutaneous transhepatic biliary drainage (PTCD) in treating malignant biliary obstruction. SUBJECTS AND METHODS: Nine patients (6 males and 3 females, average age 71.3 ± 5.5 years) with complete obstruction of the biliary tract were treated with PEG/PEJ after PTCD. The PEG/PEJ and PTCD tubes were linked outside of the abdominal wall to direct the externally drained bile back to the jejunum through the PEG/PEJ intestinal tube. Clinical symptoms and liver function were assessed following the treatment. RESULTS: The operations were successfully completed in the 9 patients within 40 min (average 35 ± 2.9 min). Clinical symptoms such as jaundice, abdominal distension, stomachache and diarrhea appeared but improved within 7 days of the operation. Serum levels of bilirubin, aspartate aminotransferase and alanine aminotransferase were reduced (p < 0.01) 4 weeks following the treatment. There were no procedural complications. CONCLUSIONS: Combined PEG/PEJ and PTCD appeared to be safe and effective in the management of malignant biliary obstruction. Further, larger-scale studies will be needed to verify findings of this report.

[Preliminary study on mechanism of therapeutic effect of Huganjiexian decoction on hepatic fibrosis].

OBJECTIVE: To observe the effects of Huganjiexian decoction on rat hepatic fibrosis and the creation of cytokines. METHODS: Rat hepatic fibrosis was induced by intraperitoneally injection of carbon tetrachloride. At the same time, these rats were treated with different dosages of Huganjiexian decoction. Sho-saiko-to compound treating group and Fufangbiejiarangan Tablets treating group were used as positive controls. After twelve weeks, all rats were executed. Histopathologic changes were observed after H.E and Masson stainings. The expression of collagen type I, collagen type III, TGF-beta 1 and PDGF-BB in liver were detected by immunohistochemical staining. RESULTS: Compared with fibrotic group, hepatic fibrosis in decoction groups was significantly improved. In decoction groups, levels of collagen type I, collagen type III, TGFbeta1 and PDGF-BB were decreased, especially in the low-dose curcumin group. The TGF-beta 1 positive percentage were 7.56%+/-2.18%, 29.25%+/-7.84%, 13.54%+/-4.15%, 21.82%+/-6.64%, 20.06%+/-7.14%, 13.78%+/-4.35%, 12.75%+/-3.98% in liver tissues from normal group, model group, low, middle, high curcumin, Sho-saiko-to compound and Fufangbiejiarangan Tablets treating groups respectively (P less than 0.05); while the PDGF-BB positive percentage were 1.68%+/-0.41%, 11.70%+/-2.28%, 3.65%+/-0.76%, 5.24%+/-1.04%, 6.37%+/-1.12%, 4.16%+/-0.61%, 3.38%+/-0.56% in liver tissues from those groups respectively (P less than 0.05). CONCLUSION: Huganjiexian decoction can improve rat hepatic fibrosis, possibly via inhibiting the expression of collagen type I, collagen type III, TGFbeta1 and PDGF-BB.

Curcumin prevents liver fibrosis by inducing apoptosis and suppressing activation of hepatic stellate cells.

This study was designed to investigate the prophylactic effects and the mechanisms of curcumin on liver fibrosis in rats. Liver fibrosis was induced in 72 Sprague Dawley rats by intraperitoneal injection of carbon tetrachloride. Rats were divided into control, liver fibrosis, high, medium, and low dose curcumin (200, 100, and 50 mg kg(-1), respectively), and colchicine (0.1 mg kg(-1)) groups. After 8 weeks of treatment, histopathological examination was performed on hepatic tissues, and liver fibrosis was graded. Hepatic stellate cells activity was examined by smooth muscle alpha-actin immunohistochemistry staining, and apoptosis was detected by terminal deoxynucleotidyl transferase dUTP nick-end labeling. The liver fibrosis score in the high, medium, and low dose curcumin group (5.79 +/- 1.80, 8.58 +/- 3.34, and 9.58 +/- 3.32, respectively) and the colchicine group (4.91 +/- 1.28) was significantly lower than in the fibrosis group (20.40 +/- 3.38, P < 0.01). The ratio of activated hepatic stellate cells in the three curcumin groups (0.97 +/- 0.69, 2.06 +/- 0.58, and 3.49 +/- 1.03, respectively) and the colchicine group (0.78 +/- 0.31) was significantly lower than in the fibrosis group (6.08 +/- 1.13, P < 0.05). The apoptosis index in the three curcumin groups (0.57 +/- 0.21, 0.37 +/- 0.22, and 0.34 +/- 0.21, respectively) was higher than in the fibrosis (0.09 +/- 0.09, P < 0.05) or the colchicine group (0.16 +/- 0.19, P < 0.05). Curcumin prevents carbon tetrachloride-induced liver fibrosis in rats. The prevention of liver fibrosis may be due to the inhibition of the activation of hepatic stellate cells and induction of their apoptosis.

[Therapeutic effects of curcumin treatment on hepatic fibrosis].

OBJECTIVE: To investigate the therapeutic effects and mechanisms of curcumin treatment on hepatic fibrosis. METHODS: A model of hepatic fibrosis was established using carbon tetrachloride intraperitoneal injections in rats. Curcumin was administered to one group of the model rats (curcumin group) and the other rats were used as controls (control group). Serum levels of ALT, AST, HA, LN, PCIII, and NO were measured, and Hyp, MDA, and SOD in liver tissues were measured. Liver tissue slides were stained with HE and Masson staining to study the pathological changes in the livers. Grades of hepatic fibrosis were evaluated according to a semiquantitative scoring system. RESULTS: In the curcumin group, serum levels of ALT, AST, NO, HA, LN, PCIII, MDA, and Hyp, were (218.50+/-48.89) U/L, (376.60+/-79.13) U/L, (47.96+/-6.53) micromol/L, (289.96+/-60.43) mg/L, (107.35+/-27.24) mg/L, (148.95+/-28.63) microg/L, (236.10+/-30.54) nmol/g, (478.40+/-75.74) microg/g and all were lower than those of the control group (693.75+/-117.57) U/L, (892.50+/-105.69) U/L, (70.95+/-10.23) micromol/L, (468.22+/-93.45) mg/L, (346.44+/-75.08) mg/L, (279.82+/-54.00) microg/L, (402.25+/-39.16) nmol/g, and (752.50+/-77.62) microg/g. The differences were significant. In the curcumin group, the level of SOD (90.39+/-21.23) in the liver tissues was significantly higher than that of the control group (46.52+/-20.01). The hepatic fibrosis scores in the curcumin group were significantly lower than those of the control group. These effects were dose-dependent. CONCLUSIONS: Curcumin reduces rat hepatic fibrosis. Anti-peroxidation and regulation of collagen metabolism in liver tissues may be involved in the therapeutic effectiveness of curcumin on hepatic fibrosis.

[Ultrastructural changes of duodenal mucosas and their significance in patients with liver cirrhosis].

OBJECTIVE: To investigate the ultrastructural changes of duodenal mucosas and their significance in patients with liver cirrhosis (PLC). METHODS: Endoscopic biopsy duodenal mucosa specimens of 60 PLC and 18 healthy volunteers as controls were obtained. Ultrastructural changes of them were studied with transmission electron microscopy. These PLC were divided into groups A, B and C according to the Child-Pugh classification. The ultrastructural changes in the duodenal mucosas of each group were rated and compared with those of the other groups. PLC with and without ultrastructural changes of duodenal mucosas were divided into a positive group and a negative group. Levels of plasma Alb, TBil, PT, plasma endotoxin, and blood ammonia of the PLC were detected and compared. RESULTS: There were 20 PLC each in groups A, B, and C. Ultrastructural changes of duodenal mucosas were found in 5 PLC of group A, 9 in group B and 17 in group C. Among the 60 PLC, 52% had some changes in their duodenal mucosas. The changes included decrease and rupture of the microvilli; also karyopyknosis, karyorrhexis, widening of the gaps of the tight junction and tumefactions of mitochodrion of duodenal mucosa epithelial cells. No ultrastructural changes of duodenal mucosas were found in the control group. The rate of changes in the three Child-Pugh class groups and in the control group were 25%, 45%, 85%, 0% respectively (P < 0.01). The level of Alb of the positive group was significantly lower than that of the negative group (P < 0.01). Levels of plasma TBil, PT, endotoxin and blood ammonia of the positive group were significantly higher or longer than those of the negative group (P < 0.01). Levels of plasma Alb of the positive and negative groups were significantly lower than those of the control group (P < 0.01). Levels of TBil, PT, plasma endotoxin and blood ammonia of the positive and negative groups were significantly higher or longer than those of the control group (P < 0.01). CONCLUSION: There were ultrastructural changes of duodenal mucosas in PLC, especially in end-stage PLC. Ultrastructural changes of intestinal mucosas in the PLC may have important pathophysiological and clinical significance.

[The study of therapeutic effects of curcumin on hepatic fibrosis and variation of correlated cytokine].

OBJECTIVE: To investigate therapeutic effects of curcumin on hepatic fibrosis and the variation of correlated cytokine. METHODS: Rat models of hepatic fibrosis were made by carbon tetrachloride. Curcumin of 10, 20, 40 mg per 100 gram weight of rat were given to these rats of curcumin group respectively from ninth week. Normal, dissolvent, model and Salvia miltiorrhiza groups were made as controls. Serum levels of ALT, AST, HA, LN, PC-III were detected; Serum levels of TGF-beta1 and TNF-alpha were detected by ELISA method; Serum levels of NO were detected by chemical method. HE and Masson staining were conducted in hepatic tissues to observe pathological variations. Grades of hepatic fibrosis were evaluated according to SSS system. Immunohistochemical staining was executed for detecting PDGF-BB in liver, and professional software for image analysis was used. RESULTS: Curcumin could decrease serum levels of ALT, AST, HA, LN, PC-III obviously, P < 0.05, which were increased in fibrotic group. Curcumin could decrease cytokine levels of NO, TGF-beta1, TNF-alpha, P < 0.05. Curcumin could obviously improve liver pathological variations of fibrotic rats. The score of hepatic fibrosis in curcumin group reduced significantly, P < 0.05. Curcumin treatment could reduce the expression of PDGF-BB, P < 0.05. These effects were dose-dependent. CONCLUSION: Curcumin can heal rat hepatic fibrosis. Effects of reducing the expression of correlated cytokines may be mechanisms of therapeutic effects of curcumin on hepatic fibrosis.