Danshensu inhibits acetaldehyde-induced proliferation and activation of hepatic stellate cell-T6

Therapeutic implications of targeting autophagy and TGF-β crosstalk for the treatment of liver fibrosis

Liver fibrosis is characterized by the excessive deposition and accumulation of extracellular matrix components, mainly collagens, and occurs in response to a broad spectrum of triggers with different etiologies. Under stress conditions, autophagy serves as a highly conserved homeostatic system for cell survival and is importantly involved in various biological processes. Transforming growth factor-β1 (TGF-β1) has emerged as a central cytokine in hepatic stellate cell (HSC) activation and is the main mediator of liver fibrosis. A growing body of evidence from preclinical and clinical studies suggests that TGF-β1 regulates autophagy, a process that affects various essential (patho)physiological aspects related to liver fibrosis. This review comprehensively highlights recent advances in our understanding of cellular and molecular mechanisms of autophagy, its regulation by TGF-β, and the implication of autophagy in the pathogenesis of progressive liver disorders. Moreover, we evaluated crosstalk between autophagy and TGF-β1 signalling and discussed whether simultaneous inhibition of these pathways could represent a novel approach to improve the efficacy of anti-fibrotic therapy in the treatment of liver fibrosis.

Salvia miltiorrhiza in thorax and abdomainal organ fibrosis: A review of its pharmacology

Organ fibrosis is a common pathological change that finally results in organ failure, which involves the destruction of parenchyma cells, the activation of mesenchymal cells and the imbalance of immunological cells. In recent years, although some breakthroughs have been made in understanding the pathogenesis and therapeutics of organ fibrosis, no registered drugs could directly target the fibrotic process, which constitutes a major biomedical challenge. Salvia miltiorrhiza (SM) is a well-known medicinal plant in China, which has been widely applied because of its pharmacological effects on anti-oxidative, anti-myocardial infarction, anti-fibrotic, anti-inflammatory, and anti-neoplastic properties. Accumulated evidence suggested that SM played critical roles against organ fibrosis in vivo and in vitro experiments by its multiple biological compounds. In this review, we discussed the recent advances on the phytochemistry and pharmacological mechanisms of SM and its active ingredients in liver, lung, kidney, and heart fibrosis, which might help to promote the treatment of fibrotic diseases in thorax and abdomainal viscera in clinic.

Danshensu alleviates bleomycin-induced pulmonary fibrosis by inhibiting lung fibroblast-to-myofibroblast transition via the MEK/ERK signaling pathway

Pulmonary fibrosis (PF) is a chronic pulmonary interstitial disease, and its pathological process is closely related to fibroblast-myofibroblast differentiation. Danshensu (DSS) has been reported to exert an anti-fibrotic effect in heart and liver. However, it is unknown whether DSS has an equally anti-fibrotic effect on lungs. To evaluate the effect of DSS on PF and demonstrate its possible molecular mechanisms, we established an in vitro model on TGF-β1 (5 ng/mL)-stimulated NIH3T3 cells and in vivo model on bleomycin (BLM) (5 mg/kg)-induced PF mice. In vitro, our results revealed that 50 μM DSS effectively inhibited the fibroblast proliferation, migration and differentiation into myofibroblast. In vivo, our results showed that DSS (28 and 56 mg/kg) reduced damaged lung structures, infiltrated inflammatory cells and accumulated areas of collagen deposition. Moreover, we showed that DSS decreased the fibroblast-specific protein 1 (FSP-1) - and α-SMA-positive areas. Meanwhile, we indicated that DSS reduced the expression of TGF-β1, α-SMA and COL-I in the lung tissues of mice. To further explore the mechanism of DSS on alleviating PF, we detected the MEK/ERK signaling pathway. Our results showed that DSS reduced the phosphorylation of MEK1/2 and ERK1/2, indicating that DSS might inhibit the MEK/ERK signaling pathway. Taken together, these results demonstrated that DSS could suppress lung fibroblast proliferation, migration and differentiation to myofibroblasts, possibly through suppressing the MEK/ERK signaling pathway, which suggested that DSS might be a potential therapeutic drug for PF treatment.

Alpha Mangostin Inhibits the Proliferation and Activation of Acetaldehyde Induced Hepatic Stellate Cells through TGF-β and ERK 1/2 Pathways

Liver fibrosis is characterized by excessive accumulation of extracellular matrix in chronic liver injury. Alcohol-induced fibrosis may develop into cirrhosis, one of the major causes of liver disease mortality. Previous studies have shown that alpha mangostin can decrease ratio of pSmad/Smad and pAkt/Akt in TGF-β-induced liver fibrosis model in vitro. Further investigation of the mechanism of action of alpha mangostin in liver fibrosis model still needs to be done. The present study aimed to analyze the mechanism of action of alpha mangostin on acetaldehyde induced liver fibrosis model on TGF-β and ERK 1/2 pathways. Immortalized HSCs, LX-2 cells, were incubated with acetaldehyde, acetaldehyde with alpha mangostin (10 and 20 μM), or alpha mangostin only (10 μM). Sorafenib 10 μM was used as positive control. LX-2 viability was counted using trypan blue exclusion method. The effect of alpha mangostin on hepatic stellate cells proliferation and activation markers and its possible mechanism of action via TGF-β and ERK1/2 were studied. Acetaldehyde was shown to increase proliferation and expression of profibrogenic and migration markers on HSC, while alpha mangostin treatment resulted in a reduced proliferation and migration of HSC and decreased Ki-67 and pERK 1/2 expressions. These findings were followed with decreased expressions and concentrations of TGF-β; decreased expression of Col1A1, TIMP1, and TIMP3; increased expression of MnSOD and GPx; and reduction in intracellular reactive oxygen species. These effects were shown to be dose dependent. Therefore, we conclude that alpha mangostin inhibits hepatic stellate cells proliferation and activation through TGF-β and ERK 1/2 pathways.

Anti-fibrotic effects of Salvia miltiorrhiza and Ligustrazine Injection on LX-2 cells involved with increased N-myc downstream-regulated gene 2 expression

OBJECTIVE

To investigate the effects of Salvia miltiorrhiza and Ligustrazine Injection (SML) on proliferation and apoptosis of human hepatic stellate cell LX-2 and the expression of N-myc downstreamregulated gene 2 (NDRG2, a tumor suppressor gene).

METHODS

HSCs from the LX-2 cell line were cultured in vitro. The proliferative state of different initial LX-2 cell numbers was measured using a 3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assay. LX-2 cells were plated in 96-well plates at an approximate density of 2.50×10⁴ cells/mL and cultured for 24 h followed by the application of different concentrations of SML (1, 2, 4 and 8 μL/mL). Cell proliferation was measured using the MTT assay at 24 and 48 h. Apoptosis was detected by flow cytometry at 24 h. LX-2 cells were treated with different concentrations of SML and extracted with protein lysis buffer. The levels of NDRG2 and β-catenin were measured by Western blot.

RESULTS

With the exception of the 1 and 2 μL/mL concentrations, 4 and 8 μL/mL SML inhibited cell proliferation in a concentration-dependent manner at 24 and 48 h (P<0.05). With the exception of the 1 and 2 μL/mL concentrations, the NDRG2 expression level was greatly increased in a concentration-dependent manner. However, the level of β-catenin was unaffected.

CONCLUSION

SML inhibit LX-2 cell proliferation in a concentration-dependent manner, and the mechanism may be associated with NDRG2 over-expression.

Potent natural products and herbal medicines for treating liver fibrosis

Liver fibrosis is a wound-healing response to chronic liver injury characterized by progressive inflammation and deposition of extracellular matrix components. The pathological condition of liver fibrosis involves secretion of extracellular matrix proteins and formation of scar tissue. The major regulators involved in hepatic fibrogenesis are the transforming growth factor (TGF)-β1/SMAD and toll-like receptor 4 (TLR4)-initiated myeloid differentiation primary response 88 gene (MyD88)/NF-ĸB cell signaling pathways. This article reviews natural products and herbal medicines that have demonstrated activity against liver fibrosis through different mechanisms of action, including anti-hepatitis B and C virus activity, anti-inflammation, inhibition of cytokine production and nuclear receptor activation, and free radical scavenging.

Protective mechanisms of medicinal plants targeting hepatic stellate cell activation and extracellular matrix deposition in liver fibrosis

During chronic liver injury, hepatic stellate cells (HSC) are activated and proliferate, which causes excessive extracellular matrix (ECM) deposition, leading to scar formation and fibrosis. Medicinal plants are gaining popularity as antifibrotic agents, and are often safe, cost-effective, and versatile. This review aims to describe the protective role and mechanisms of medicinal plants in the inhibition of HSC activation and ECM deposition during the pathogenesis of liver fibrosis. A systematic literature review on the anti-fibrotic mechanisms of hepatoprotective plants was performed in PubMed, which yielded articles about twelve relevant plants. Many of these plants act via disruption of the transforming growth factor beta 1 signaling pathway, possibly through reduction in oxidative stress. This reduction could explain the inhibition of HSC activation and reduction in ECM deposition. Medicinal plants could be a source of anti-liver fibrosis compounds.