Induction of apoptosis by tanshinone I via cytochrome c release in activated hepatic stellate cells

Working with Immortalized Hepatic Stellate Cell Lines

Hepatic stellate cells (HSCs) are the major cellular source of extracellular matrix production in the liver. Therefore, this cell population has received considerable attention in studies investigating fundamental features of hepatic fibrosis. However, the limited supply and ever-increasing demand for these cells, combined with the additional tightening of formal standards in animal welfare policy, make working with these primary cells increasingly difficult. Moreover, researchers working in biomedical research are challenged to implement the 3R principle of "replacement," "reduction," and "refinement" in their work. This principle, originally proposed in 1959 by William M. S. Russell and Rex L. Burch, is now widely endorsed by legislators and regulatory bodies in many countries as a roadmap to tackle the ethical dilemma associated with animal experimentation. As such, working with immortalized HSC lines is a good alternative to limit the number of animals and their suffering in biomedical research. This article summarizes issues that need to be considered when working with established HSC cell lines and provides general guidelines for the maintenance and storage of HSC lines from mouse, rat, and humans.

Genetic Characterization of Rat Hepatic Stellate Cell Line HSC-T6 for In Vitro Cell Line Authentication

Immortalized hepatic stellate cells (HSCs) established from mouse, rat, and humans are valuable in vitro models for the biomedical investigation of liver biology. These cell lines are homogenous, thereby providing consistent and reproducible results. They grow more robustly than primary HSCs and provide an unlimited supply of proteins or nucleic acids for biochemical studies. Moreover, they can overcome ethical concerns associated with the use of animal and human tissue and allow for fostering of the 3R principle of replacement, reduction, and refinement proposed in 1959 by William M. S. Russell and Rex L. Burch. Nevertheless, working with continuous cell lines also has some disadvantages. In particular, there are ample examples in which genetic drift and cell misidentification has led to invalid data. Therefore, many journals and granting agencies now recommend proper cell line authentication. We herein describe the genetic characterization of the rat HSC line HSC-T6, which was introduced as a new in vitro model for the study of retinoid metabolism. The consensus chromosome markers, outlined primarily through multicolor spectral karyotyping (SKY), demonstrate that apart from the large derivative chromosome 1 (RNO1), at least two additional chromosomes (RNO4 and RNO7) are found to be in three copies in all metaphases. Additionally, we have defined a short tandem repeat (STR) profile for HSC-T6, including 31 species-specific markers. The typical features of these cells have been further determined by electron microscopy, Western blotting, and Rhodamine-Phalloidin staining. Finally, we have analyzed the transcriptome of HSC-T6 cells by mRNA sequencing (mRNA-Seq) using next generation sequencing (NGS).

Tanshinone I attenuates fibrosis in fibrotic kidneys through down-regulation of inhibin beta-A

BACKGROUND

Tanshinone I (Tan-I), an ingredient of Salvia miltiorrhiza, displays protective effects in several disease models. We aim to study the effect of Tan-I on renal fibrosis and explore its underlining mechanism.

METHODS

Rat renal fibroblasts (NRK-49F) were used as an in vitro model to study the effect of Tan-I. Mouse renal fibrosis model was induced by unilateral ureteral obstruction (UUO) or peritoneally injection of aristolochic acid I (AAI).

RESULTS

We found that Tan-I dose-dependently inhibited the expression of pro-fibrotic markers in rat renal fibroblasts. Masson staining and Western blotting analysis showed that Tan-I treatment attenuated renal fibrosis in UUO or AAI induced fibrotic kidneys. RNA sequencing analysis identified inhibin beta-A (INHBA), a ligand of TGF-β superfamily, as a downstream target of Tan-I in fibrotic kidneys, which were further verified by qPCR. Western blotting analysis showed that INHBA is up-regulated in UUO or AAI induced fibrotic kidneys and Tan-I reduced the expression of INHBA in fibrotic kidneys. Inhibition of INHBA by Tan-I was further confirmed in rat fibroblasts. Moreover, knockdown of INHBA reduced the expression of pro-fibrotic markers and abolished the ani-fibrotic effect of Tan-I in rat renal fibroblasts.

CONCLUSIONS

We conclude that Tan-I attenuates fibrosis in fibrotic kidneys through inhibition of INHBA.

Evaluation of the anti-inflammatory effects of synthesised tanshinone I and isotanshinone I analogues in zebrafish

During inflammation, dysregulated neutrophil behaviour can play a major role in a range of chronic inflammatory diseases, for many of which current treatments are generally ineffective. Recently, specific naturally occurring tanshinones have shown promising anti-inflammatory effects by targeting neutrophils in vivo, yet such tanshinones, and moreover, their isomeric isotanshinone counterparts, are still a largely underexplored class of compounds, both in terms of synthesis and biological effects. To explore the anti-inflammatory effects of isotanshinones, and the tanshinones more generally, a series of substituted tanshinone and isotanshinone analogues was synthesised, alongside other structurally similar molecules. Evaluation of these using a transgenic zebrafish model of neutrophilic inflammation revealed differential anti-inflammatory profiles in vivo, with a number of compounds exhibiting promising effects. Several compounds reduce initial neutrophil recruitment and/or promote resolution of neutrophilic inflammation, of which two also result in increased apoptosis of human neutrophils. In particular, the methoxy-substituted tanshinone 39 specifically accelerates resolution of inflammation without affecting the recruitment of neutrophils to inflammatory sites, making this a particularly attractive candidate for potential pro-resolution therapeutics, as well as a possible lead for future development of functionalised tanshinones as molecular tools and/or chemical probes. The structurally related β-lapachones promote neutrophil recruitment but do not affect resolution. We also observed notable differences in toxicity profiles between compound classes. Overall, we provide new insights into the in vivo anti-inflammatory activities of several novel tanshinones, isotanshinones, and structurally related compounds.

Hepatoprotective and Anti-fibrotic Agents: It's Time to Take the Next Step

Hepatic fibrosis and cirrhosis cause strong human suffering and necessitate a monetary burden worldwide. Therefore, there is an urgent need for the development of therapies. Pre-clinical animal models are indispensable in the drug discovery and development of new anti-fibrotic compounds and are immensely valuable for understanding and proofing the mode of their proposed action. In fibrosis research, inbreed mice and rats are by far the most used species for testing drug efficacy. During the last decades, several hundred or even a thousand different drugs that reproducibly evolve beneficial effects on liver health in respective disease models were identified. However, there are only a few compounds (e.g., GR-MD-02, GM-CT-01) that were translated from bench to bedside. In contrast, the large number of drugs successfully tested in animal studies is repeatedly tested over and over engender findings with similar or identical outcome. This circumstance undermines the 3R (Replacement, Refinement, Reduction) principle of Russell and Burch that was introduced to minimize the suffering of laboratory animals. This ethical framework, however, represents the basis of the new animal welfare regulations in the member states of the European Union. Consequently, the legal authorities in the different countries are halted to foreclose testing of drugs in animals that were successfully tested before. This review provides a synopsis on anti-fibrotic compounds that were tested in classical rodent models. Their mode of action, potential sources and the observed beneficial effects on liver health are discussed. This review attempts to provide a reference compilation for all those involved in the testing of drugs or in the design of new clinical trials targeting hepatic fibrosis.

Experimental models of liver fibrosis

Hepatic fibrosis is a wound healing response to insults and as such affects the entire world population. In industrialized countries, the main causes of liver fibrosis include alcohol abuse, chronic hepatitis virus infection and non-alcoholic steatohepatitis. A central event in liver fibrosis is the activation of hepatic stellate cells, which is triggered by a plethora of signaling pathways. Liver fibrosis can progress into more severe stages, known as cirrhosis, when liver acini are substituted by nodules, and further to hepatocellular carcinoma. Considerable efforts are currently devoted to liver fibrosis research, not only with the goal of further elucidating the molecular mechanisms that drive this disease, but equally in view of establishing effective diagnostic and therapeutic strategies. The present paper provides a state-of-the-art overview of in vivo and in vitro models used in the field of experimental liver fibrosis research.

Liver fibrosis and protection mechanisms action of medicinal plants targeting apoptosis of hepatocytes and hepatic stellate cells

Following chronic liver injury, hepatocytes undergo apoptosis leading to activation of hepatic stellate cells (HSC). Consequently, activated HSC proliferate and produce excessive extracellular matrix, responsible for the scar formation. The pandemic trend of obesity, combined with the high incidence of alcohol intake and viral hepatitis infections, highlights the urgent need to find accessible antifibrotic therapies. Treatment strategies should take into account the versatility of its pathogenesis and act on all the cell lines involved to reduce liver fibrosis. Medicinal plants are achieving popularity as antifibrotic agents, supported by their safety, cost-effectiveness, and versatility. This review will describe the role of hepatocytes and HSC in the pathogenesis of liver fibrosis and detail the mechanisms of modulation of apoptosis of both cell lines by twelve known hepatoprotective plants in order to reduce liver fibrosis.

Recent Progress of Research on Herbal Products Used in Traditional Chinese Medicine: the Herbs belonging to The Divine Husbandman's Herbal Foundation Canon ( Shén Nóng Běn Cǎo Jīng)

This article will review selected herbal products from Chinese Materia Medica that are used in Traditional Chinese Medicine. The herbs come from the upper, middle, and lower class medicines as listed in The Divine Husbandman's Herbal Foundation Canon (神農本草經 Shén Nóng Běn Cǎo Jīng). The review will focus on the active constituents of the herbs and their bioactivities, with emphasis on the most recent progress in research for the period of 2003 to 2011.

The anticancer properties of Salvia miltiorrhiza Bunge (Danshen): a systematic review

Salvia miltiorrhiza Bunge (Danshen in Chinese) is a classical Huoxue Huayu (a traditional Chinese medical term means promoting blood circulation and removing blood stasis) herb with 1000 years of clinical application. It mainly contains two groups of ingredients: the hydrophilic phenolic acids and the lipophilic tanshinones. Both groups have demonstrated multiple bioactivities, such as antioxidative stress, antiplatelet aggregation, anti-inflammation, among others. Recent data have demonstrated that its lipophilic compounds, especially the tanshinones, show potent anticancer activities both in vitro and in vivo. The anticancer effects of the hydrophilic phenolic acids have also been reported. Furthermore, tanshinones provide structural skeletons for chemical modifications, allowing for a series of derivatives of interests. This review provides a systematic summary of the anticancer profile and the underlying mechanisms of the bioactive compounds isolated from Danshen with special emphasis on tanshinones, aiming to bring new insights for further research and development of this ancient herb.

PF2401-SF, standardized fraction of Salvia miltiorrhiza, induces apoptosis of activated hepatic stellate cells in vitro and in vivo

During the course of our attempts to develop a potential herbal medicine, we had previously prepared PF2401-SF, a standardized fraction of S. miltiorrhiza, and reported its hepatoprotective activity in vitro as well as in vivo. Since apoptosis of activated hepatic stellate cells (HSCs) is a well-accepted anti-fibrotic strategy, in this study, we investigated the direct effect of PF2401-SF on t-HSC/Cl-6 cells in vitro and on CCl₄-induced liver injury in vivo. We evaluated the activation and cleavage of hallmarkers of apoptosis, namely, caspase 3, 8, 9 and PARP. Upregulation of the pro-apoptotic Bax protein and downregulation of the anti-apoptotic Bcl2 protein were also analyzed. Furthermore, in the PF2401-SF treated rats, apoptosis induction of activated HSCs was demonstrated by reduced distribution of α-SMA-positive cells and the presence of high number of TUNEL-positive cells in vivo. Our data suggest that PF2401-SF can mediate HSCs apoptosis induction, and may be a potential herbal medicine for the treatment of liver fibrosis.

Apoptotic effect of propyl gallate in activated rat hepatic stellate cells

Hepatic stellate cells (HSCs) play a central role in liver fibrosis. Inhibition of HSC growth and induction of apoptosis have been proposed as therapeutic strategies for the treatment and prevention of liver fibrosis. Propyl gallate (PG) is an antioxidant widely used in processed foods, cosmetics and medicinal preparations. However, the anti-fibrotic effect of PG in liver injury is unclear. In this study, we investigated whether PG could induce apoptosis in activated HSCs. Treatment of activated HSCs with PG inhibited cell viability in a dose- and time-dependent manner. PG induced apoptosis as demonstrated by morphological changes, poly(ADP-ribose) polymerase (PARP) cleavage, caspase-3 cleavage, increased Bad expression, and decreased Bcl-2 protein expression. Through stimulation of the activation of c-Jun NH2-terminal protein kinase (JNK) and p38 mitogen-activated protein kinases (MAPK) by PG treatment, we demonstrated that JNK and p38 MPAK are not involved in PG-induced apoptosis using their specific inhibitors. Taken together, these findings indicate that PG induces apoptosis in activated HSCs. The potential anti-fibrotic effect of PG warrants further evaluation.

Tanshinone IIA and tanshinone I production by Trichoderma atroviride D16, an endophytic fungus in Salvia miltiorrhiza

In this study the isolation of an endophytic fungus from the root of the medicinal herb Salvia miltiorrhiza Bunge is reported for the first time. The fungus produced tanshinone I and tanshinone IIA in rich mycological medium (potato dextrose broth) under shake flask and bench scale fermentation conditions. The fungus was identified as Trichoderma atroviride by its morphology and authenticated by ITS analysis (ITS1 and ITS2 regions and the intervening 5.8S rDNA region). Tanshinone I and tanshinone IIA were identified by HPLC and LC-HRMS/MS and confirmed through comparison with authentic standards. This endophytic fungus has significant scientific and industrial potential to meet the pharmaceutical demands for tanshinone I and tanshinone IIA in a cost-effective, easily accessible and reproducible way.

Inhibition of glucose-induced vascular endothelial growth factor expression by Salvia miltiorrhiza hydrophilic extract in human microvascular endothelial cells: evidence for mitochondrial oxidative stress

AIM OF STUDY

Diabetes mellitus is frequently combined with vascular diseases, which are associated with the expression of vascular endothelial growth factor (VEGF). An approach that can reverse the induction of VEGF by hyperglycemia may potentially benefit the outcome of diabetic patients. Therefore, in the present study, we investigated the effect of Salvia miltiorrhiza (S. miltiorrhiza) hydrophilic extract on the expression of VEGF induced by high concentration of glucose.

MATERIALS AND METHODS

Vector of VEGF promoter luc was transiently transfected into HMEC-1 cells, and luciferase activity was measured to determine the promoter activity. In order to investigate the mechanism of Salvia miltiorrhiza hydrophilic extract, mitochondrial uncoupling protein 2(UCP2) was knockdown by using UCP2 siRNA. The expression of VEGF was obtained by using quantitative RT-PCR and dot blot. The level of reactive oxygen species (ROS) was expressed by the level of 2',7'-dichlorfluorescein.

RESULTS

Exposure of HMEC-1 cells to 30 mM glucose resulted in a significant increase in the expression of VEGF mRNA (5.7 fold at 3mM glucose, P<0.005), and an increase of ROS formation (2.4 fold at 3mM glucose, P<0.005). These effects were completely antagonized by an inhibitor of electron transport chain complex II, thenoyltrifluoroacetone (TTFA) and an uncoupler of oxidative phosphorylation, carbonylcyanide-m-chlorophenylhydrazone (CCCP). Addition of Salvia miltiorrhiza hydrophilic extract (10 μg/ml) led to a significant decrease of VEGF mRNA and ROS formation in 30 mM glucose condition. Interestingly, knockdown of mitochondrial UCP-2 by UCP-2 siRNA abolished the reduction of VEGF expression and ROS formation by Salvia miltiorrhiza hydrophilic extract.

CONCLUSIONS

These findings indicated that Salvia miltiorrhiza hydrophilic extract effectively reversed induction of VEGF expression by high glucose via ameliorating mitochondrial oxidative stress. Salvia miltiorrhiza hydrophilic extract can potentially be an effective antioxidant therapy for the treatment of diabetic chronic vascular complication.

Bax and calpain mediate excitotoxic oligodendrocyte death induced by activation of both AMPA and kainate receptors

Sustained activation of AMPA and kainate receptors in rat oligodendrocytes induces cytosolic calcium overload, mitochondrial depolarization, and an increase of reactive oxygen species, resulting in cell death. Here, we provide evidence that Bax, a proapoptotic member of the Bcl-2 protein family, is involved in excitotoxic apoptotic death of oligodendrocytes and that calpain mediates Bax activation. Cultured Bax(-/-) oligodendrocytes, obtained from the optic nerve of Bax knock-out mice, were resistant to AMPA and kainate receptor-mediated insults. In turn, both mitochondrial calcium uptake and mitochondrial alterations after excitotoxic insults were diminished in Bax-null oligodendrocytes. Moreover, pretreatment with furosemide, a blocker of Bax translocation to mitochondria, significantly protected rat and mouse oligodendrocytes from AMPA- and kainate-induced damage; in contrast, bongkrekic acid, a blocker of the mitochondrial permeability transition pore, had no effect. Finally, we analyzed the participation of calpain, which cleaves Bax and is activated by AMPA and kainate, in oligodendrocyte death. Pretreatment with 3-(4-iodophenyl)-2-mercapto-(Z)-2-propenoic acid (PD150606), a broad cell-permeable calpain inhibitor, and two additional calpain inhibitors diminished Bax activation, inhibited its translocation to mitochondria, and attenuated all apoptotic events resulting from excitotoxic insults to rat oligodendrocytes. Together, these results indicate that Bax and calpain are essential intermediaries of the mitochondria-dependent death pathway, triggered by AMPA and kainate receptor activation in oligodendrocytes.

Nicotinamide inhibits hepatic fibrosis by suppressing DNA synthesis and enhancing apoptosis of hepatic stellate cells

Liver fibrosis and its end-stage disease, cirrhosis, are major worldwide healthcare burdens. In this study, we evaluated the inhibitory effects of nicotinamide (NA) on rat hepatic fibrogenesis and investigated its underlying mechanism. We examined the inhibitory effects of NA in vivo by using F344 rats in a thioacetamide (TAA)-induced fibrogenesis model and assessed the inhibitory effects in vitro by using the rat hepatic stellate cell line THSC-Cl6. In vivo, NA significantly attenuated liver fibrosis in TAA-treated rats as assessed by histological analysis using hematoxylin-eosin and Masson's trichrome staining. In vitro, NA inhibited viability of THSC-Cl6 cells in a dose- and time-dependent manner, suppressed DNA synthesis, and induced apoptosis. Transcription of collagen mRNA and expression of alpha smooth muscle actin (the hallmark of activated hepatic stellate cells) were reduced by NA. Expression of the cell cycle-related proteins cyclin E, cyclin D1, and cyclin-dependent kinase (cdk)4, was reduced by NA treatment, but expression of cyclin A and cdk2 was not. Expression of the cdk inhibitors p16 and p21 was decreased by NA treatment, whereas expression of p27 was increased. It appears that NA inhibits rat hepatic fibrogenesis by suppressing DNA synthesis and enhancing apoptosis of hepatic stellate cells.

Biosynthesis, total syntheses, and antitumor activity of tanshinones and their analogs as potential therapeutic agents

Tanshinones are a series of abietane diterpenes, isolated exclusively from Salvia miltiorrhiza and related species. More than 40 tanshinones and their analogs have been isolated since the 1930s. Their biosynthetic pathway correlates with the MEP/DOXP pathway, and many key enzymes, such as mCPS, are responsible for establishing their molecular scaffolds and stereospecificity. Because of their unique structural characteristics and promising biological activities, total syntheses of various tanshinones have attracted the interest of many synthetic chemists, including R. H. Thomson, H. Kakisawa, R. L. Danheiser, Y. Inouye and J. K. Snyder. Tanshinones and their analogs exhibit interesting and broad antitumor activity in various cell and animal models. Most recently, the tanshinone analog neo-tanshinlactone has shown potent and selective activity against breast cancer. This review will discuss the biosynthesis, total syntheses, and antitumor activities of tanshinones,especially neo-tanshinlactone and its analogs.

Thiol redox systems and protein kinases in hepatic stellate cell regulatory processes

Hepatic stellate cells (HSC) are the major producers of collagen in the liver and their conversion from resting cells to a proliferating, contractile and fibrogenic phenotype ('activation') is a critical step, leading to liver fibrosis characterized by deposition of excessive extracellular matrix. Cytokines, growth factors, reactive oxygen and nitrogen species (ROS/RNS), lipid peroxides and their products deriving from hepatocytes, Kupffer cells and other cells converge on HSC and influence their activation. This review focuses on glutathione and thioredoxin pathways, with particular emphasis on their role in HSC. These two systems have been shown to act in the metabolism of hydrogen peroxide, control of thiol redox balance and regulation of signalling pathways. Particular attention is paid to mitochondria and NADPH oxidase. Detailed knowledge of specific signalling, redox conditions and apoptotic processes will be of help in devising proper pharmacological treatments for liver fibrosis.

Structural elucidation of metabolites of tanshinone I and its analogue dihydrotanshinone I in rats by HPLC-ESI-MSn

Tanshinone I and its analogue dihydrotanshinone I are the major active components isolated from Salvia miltiorrhiza Bunge and Salvia Przewalskii Maxim. These compounds have been found to possess significant antibacterial, anti-dermatophytic, antioxidant, anti-inflammatory and anticancer activities. Fifteen phase I metabolites and two phase II metabolites of tanshinone I and dihydrotanshinone I in rat bile were elucidated and identified by a sensitive HPLC-ESI-MS(n) method. The molecular structures of the metabolites are presented on the basis of the characteristics of their precursor ions, product ions and chromatographic retention times. The results indicate that the phase I metabolites are biotransformed through four main pathways: dehydrogenation, hydroxylation, furan ring cleavage and oxidation metabolism. Phase II metabolites were mainly identified as the sulfated conjugates which showed a characteristic neutral loss of 80 Da. The biotransformed pathways of tanshinone I and dihydrotanshinone I were proposed on the basis of the investigation.

Fenretinide stimulates the apoptosis of hepatic stellate cells and ameliorates hepatic fibrosis in mice

AIM

To investigate whether fenretinide, a clinically proved apoptosis-inducing chemopreventive agent in tumor cells, can induce apoptosis in hepatic stellate cells (HSCs) and resolve hepatic fibrosis.

METHODS

CCl(4)-induced liver fibrosis in mice and rat activated hepatic stellate cells (HSC-T6) as well as hepatocytes (BRL-3A) were studied.

RESULTS

The duplex staining of proliferating cell nuclear antigen and alpha- smooth muscle actin or terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling and alpha- smooth muscle actin demonstrated that fenretinide executed its anti-fibrosis effect in liver by inducing apoptosis rather than inhibiting proliferation of HSCs, while it had no apparently apoptotic effect on hepatocytes. Fenretinide could elicit apoptosis of HSC-T6 in vitro at the concentration range from 0.5 to 5 microM, but at higher concentrations >/=5 microM was required to induce apoptosis in hepatocytes (BRL-3A).

CONCLUSION

Further studies using malondialdehyde measurement, Western blot, antioxidant, inhibitors for p53, caspase 8 and 9 - as well as anti-Fas neutralizing antibody - have shown that in HSC-T6, fenretinide-induced apoptosis involves a reactive oxygen species (ROS)-generated, P53-independent, mitochondria-associated intrinsic pathway, whereas in hepatocytes (BRL-3A), a ROS-generated, P53-dependent, Fas-related extrinsic pathway is triggered only at high concentration.

Tanshinone II A induces apoptosis and S phase cell cycle arrest in activated rat hepatic stellate cells

Tanshinone IIA, a major component extracted from the traditional herbal medicine, Salvia miltiorrhiza Bunge, improves blood circulation and treats chronic hepatitis and hepatic fibrosis. Activation of hepatic stellate cells (HSCs) is the predominant event in liver fibrosis. The therapeutic goal in liver fibrosis is the reversal of fibrosis and selective clearance of activated HSCs. We used rat HSCs transformed by Simian virus 40 (t-HSC/Cl-6) to overcome the limitations inherent in studying subcultures of HSCs. Treatment of t-HSC/Cl-6 cells with tanshinone IIA inhibited cell viability in a dose- and time-dependent manner. Tanshinone IIA induced apoptosis as demonstrated by DNA fragmentation, poly(ADP-ribose) polymerase and caspase-3 cleavage, increased Bax/Bcl-2 protein ratio, and depolarization of mitochondrial membranes to facilitate cytochrome c release into the cytosol. Furthermore, this compound markedly induced S phase cell cycle arrest, and down-regulated cyclins A and E, and cdk2. Thus, tanshinone IIA induces apoptosis and S phase cell cycle arrest in rat HSCs in vitro.

Effects of sodium tanshinone II A sulphonate on hypoxic pulmonary hypertension in rats in vivo and on Kv2.1 expression in pulmonary artery smooth muscle cells in vitro

AIM OF THE STUDY

To investigate the effect of sodium tanshinone IIA sulphonate (STS), a water-soluble derivative of tanshinone II A, on hypoxic pulmonary hypertension (HPH) in rats and its underlying mechanisms.

MATERIALS AND METHODS

Rats were exposed to hypoxia for two or three weeks, pretreated with or without STS. We detected mean pulmonary arterial pressure (mPAP), the ratio of right ventricle weight to left ventricle with septum weight [RV/(LV+S)], wall thickness and voltage-activated potassium channel (Kv) 2.1 mRNA level of pulmonary arteries (PAs), respectively, and the in vitro effects of STS on proliferation and Kv2.1 expression of cultured pulmonary smooth muscle cells (PASMCs) from normal rats. Cell proliferation was determined by 3-(4,5-dimethylthiazal-2-yl)-2,5-diphenyltetrazoliumbromiede (MTT) assay and direct cell counting. Kv2.1 mRNA and protein level were evaluated by reverse transcription-polymerase chain reaction and Western blot, respectively.

RESULTS

Chronic hypoxia increased values of mPAP and RV/(LV+S) and inhibited Kv2.1 mRNA level in PAs. Three weeks' daily STS pretreatment inhibited the hypoxia-induced increased mPAP and RV/(LV+S), pulmonary arterial thickening and up-regulated Kv2.1 mRNA level in PAs. Further study in vitro showed that STS suppressed significantly hypoxia-induced PASMCs proliferation and inhibition of Kv2.1 expression in PASMCs.

CONCLUSIONS

STS might play protective effects on HPH through decreasing mPAP, V/(LV+S) and inhibiting structural remodeling in distal PAs. The mechanism of these effects may be attributed to inhibiting PASMCs proliferation and stimulating Kv2.1 expression.

Preventive effects of a purified extract isolated from Salvia miltiorrhiza enriched with tanshinone I, tanshinone IIA and cryptotanshinone on hepatocyte injury in vitro and in vivo

Salvia miltiorrhiza is traditionally used to treat liver disease in Asia. In this study, we tested the ability of a purified extract of S. miltiorrhiza (PF2401-SF) and its constituents, tanshinone I, tanshinone IIA, and cryptotanshinone, to protect against acute and subacute liver damage induced by carbon tetrachloride by measuring serum transaminase levels, the reduced form of glutathione (GSH), antioxidant enzyme activities, and lipid peroxidation levels in the liver. We also evaluated their ability to protect primary cultured rat hepatocytes from tertiary-butylhydroperoxide (tBH) or d-galactosamine (GalN). PF2401-SF was protective at 50-200mg/kg per day in acute liver injury and 25-100mg/kg per day in subacute liver injury. Tanshinone I, tanshinone IIA, and cryptotanshinon (40 microM), inhibited lactate dehydrogenase leakage, GSH depletion, lipid peroxidation and free radical generation in vitro. PF2401-SF and its major constituents, tanshinone I, tanshinone IIA and cryptotanshinone, can protect against liver toxicity in vivo and in vitro due to its antioxidant effects.

Reactive oxygen species-mediated kinase activation by dihydrotanshinone in tanshinones-induced apoptosis in HepG2 cells

The role of reactive oxygen species (ROS) and p38 mitogen-activated protein kinases (MAPK) in tanshinones-induced apoptosis was investigated in HepG2 cells in this study. The major tanshinones (cryptotanshinone, dihydrotanshinone, tanshinone I, tanshinone IIA), isolated from Salvia miltiorrhiza, inhibit cell growth and induce caspase-dependent apoptosis concentration-dependently, with dihydrotanshinone being the most potent. All four tanshinones were found to induce ROS generation, but only dihydrotanshinone can induce activation of p38 MAPK. The p38 MAPK activation by dihydrotanshinone was inhibited by N-acetyl cysteine pretreatment. It is thus concluded that ROS-mediated p38 MAPK activation plays a vital role in dihydrotanshinone-induced apoptosis in HepG2 cells.

Simultaneous determination of tanshinone I, dihydrotanshinone I, tanshinone IIA and cryptotanshinone in rat plasma by liquid chromatography-tandem mass spectrometry: application to a pharmacokinetic study of a standardized fraction of Salvia miltiorrhiza, PF2401-SF

A rapid, sensitive and selective liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for the simultaneous determination of tanshinone I, dihydrotanshinone I, tanshinone IIA and cryptotanshinone, the active components of Salvia miltiorrhiza in rat plasma, was developed. After liquid-liquid extraction with tariquidar as an internal standard, tanshinone I, dihydrotanshinone I, tanshinone IIA and cryptotanshinone were eluted from an Atlantis dC18 column within 5 min with a mixture of methanol and ammonium formate (10 mm, pH 6.5; 85:15, v/v). The analytes were detected by an electrospray ionization tandem mass spectrometry in the selected reaction monitoring (SRM) mode. The standard curves were linear (r=0.999) over the concentration range of 0.25-80 ng/mL for tanshinone I, dihydrotanshinone I, tanshinone IIA and cryptotanshinone in rat plasma. The coefficients of variation and the relative errors of tanshinone I, dihydrotanshinone I, tanshinone IIA and cryptotanshinone for intra- and inter-assay at four quality control (QC) concentrations were 1.1-5.1% and -4.0-6.0%, respectively. The lower limit of quantification for tanshinone I, dihydrotanshinone I, tanshinone IIA and cryptotanshinone was 0.25 ng/mL from 100 microL of plasma. This method was successfully applied to the pharmacokinetic study of tanshinone I, dihydrotanshinone I, tanshinone IIA and cryptotanshinone after oral administration of PF2401-SF, the standardized fraction of Salvia miltiorrhiza enriched with tanshinone I, dihydrotanshinone I, tanshinone IIA and cryptotanshinone to male Sprague-Dawley rats.

Immortal hepatic stellate cell lines: useful tools to study hepatic stellate cell biology and function?

At the cellular level, the activation and transdifferentiation of quiescent hepatic stellate cells (HSC) into myofibroblasts is the key process involved in hepatic fibrogenesis that is associated with an increased and altered deposition of extracellular matrix components in the liver. The temporal sequence of molecular events associated with stellate cell activation turned out to be appropriately mimicked when HSC isolated from normal livers are cultured on uncoated plastic surface. Therefore, cultured primary cells isolated from rodents and human beings are common in vitro models in investigations addressing these issues of hepatic stellate biology and function. However, the limited supply, cost-effective isolation procedure and the ever growing need have resulted in efforts to establish immortalized stellate cell lines having the advantage of virtually unlimited access. They allow rapid screening for disease-associated factors and restrict the necessary number of animal experiments. From the first description of an immortal HSC line in 1986, a huge number of studies were conducted with these established cell lines. However, differences in morphology, growth characteristics and anomalies of chromosome number and structure make the applications of these models questionable. Here, we summarize the history and cellular characteristics of respective cell lines and discuss the differences of continuous HSC lines and their primary counterparts.

PF2401-SF, standardized fraction of Salvia miltiorrhiza and its constituents, tanshinone I, tanshinone IIA, and cryptotanshinone, protect primary cultured rat hepatocytes from bile acid-induced apoptosis by inhibiting JNK phosphorylation

Bile acid-induced hepatocyte apoptosis plays an important role in cholestatic liver disease, and the role of apoptosis may be of therapeutic interest in preventing liver disease. The dried root of Salvia miltiorrhiza Bunge (Labiatae) has been used traditionally to treat liver diseases. We investigated the antiapoptotic effects of a standardized fraction of S. miltiorrhiza (PF2401-SF) and its components, tanshinone I, tanshinone IIA, and cryptotanshinone, in primary cultured rat hepatocytes. PF2401-SF was enriched with tanshinone I (11.5%), tanshinone IIA (41.0%), and cryptotanshinone (19.1%). Glycochenodeoxycholic acid (GCDC)-induced apoptosis, as shown by DNA fragmentation, poly(ADP-ribose) polymerase cleavage, and activation of caspases-8, -9, and -3. PF2401-SF and its components, tanshinone I, tanshinone IIA, and cryptotanshinone showed antiapoptotic activity. Treatment with PF2401-SF or with its components significantly inhibited the generation of intracellular reactive oxygen species. Hydrophobic bile acids activate c-Jun-NH(2)-terminal kinase (JNK), p38 mitogen-activated protein kinases (MAPK), and extracellular signal-regulated kinase 1/2, and PF2401-SF inhibited the phosphorylation of JNK and p38. All three components of PF2401-SF inhibited JNK phosphorylation. Addition of inhibitors of MAPK showed that inhibition of JNK decreased apoptosis. These data indicate that PF2401-SF and its components protect hepatocytes from GCDC-induced apoptosis in vitro by inhibiting JNK.

Bakuchiol-induced caspase-3-dependent apoptosis occurs through c-Jun NH2-terminal kinase-mediated mitochondrial translocation of Bax in rat liver myofibroblasts

Liver fibrosis and cirrhosis may be reversible, possibly through the selective clearance of activated hepatic stellate cells/myofibroblasts by apoptosis. Hepatic stellate cells transdifferentiate into myofibroblast-phenotype cells in culture, a process that recapitulates hepatic stellate cell activation in vivo. Bakuchiol, a prenylated phenolic terpene isolated from the seed of Psoralea corylifolia L. (Leguminosae), reduced activated hepatic stellate cells when treated to rats during liver injury recovery period as demonstrated by alpha-smooth muscle actin immunostaining in rat liver and induced apoptosis in activated hepatic stellate cells/myofibroblasts as demonstrated by DNA fragmentation, activation of caspase-3, release of cytochrome c into the cytoplasm, translocation of Bax into mitochondria, and the proteolytic cleavage of poly(ADP-ribose) polymerase (PARP) in vitro. Bakuchiol-induced apoptosis was prevented by z-DEVD-fmk, a specific inhibitor of caspase-3, and z-VAD-fmk, a general caspase inhibitor, suggesting that bakuchiol-induced apoptosis occurs through a caspase-3-dependent pathway in vitro. Bakuchiol treatment stimulated the activation of extracellular signal-regulated kinase 1/2 (ERK), c-Jun NH2-terminal protein kinase (JNK), and p38 mitogen-activated protein kinases (MAPK) in vitro. Pretreatment with SP600125 attenuated the bakuchiol-induced translocation of Bax into mitochondria, cytochrome c release into the cytosol, caspase-3 activation, and PARP cleavage. In contrast, preincubation with SB203580, a p38 MAPK inhibitor, and U0126, an ERK inhibitor, had no effect on bakuchiol-induced cell death and caspase-3 activity. Taken together, these findings indicate that bakuchiol induces caspase-3-dependent apoptosis through the activation of JNK, followed by Bax translocation into mitochondria in rat liver myofibroblasts.

Tetrandrine stimulates the apoptosis of hepatic stellate cells and ameliorates development of fibrosis in a thioacetamide rat model

AIM: To investigate the therapeutic effect of tetrandrine on liver fibrosis induced by thioacetamide in rats in vivo and in vitro.

METHODS: In vitro study: we investigated the effect of tetrandrine on the apoptosis of rat hepatic stellate cells transformed by simian virus 40 (T-HSC/Cl-6), which retains the features of activated cells. In vivo study: hepatic fibrosis was induced in rats by thioacetamide. Tetrandrine was given orally to rats at doses of 5, 10 or 20 mg/kg for 4 wk compared with intraperitoneal injection of interferon-г.

RESULTS: In vitro study: 5, 10 or 25 μg/mL of tetrandrine-induced activation of caspase-3 in t-HSC/Cl-6 cells occurred dose-dependently. In vivo study: tetrandrine treatment as well as interferon-г significantly ameliorated the development of fibrosis as determined by lowered serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin (T-Bil) and the levels of liver hydroxyproline (Hyp), hyaluronic acid (HA), laminin (LN) and also improved histological findings. The effects of tetrandrine at the concentration of 20 mg/kg were better than the other concentration groups.

CONCLUSION: Tetrandrine promotes the apoptosis of activated HSCs in vitro. Tetrandrine administration can prevent liver fibrosis and liver damage induced by thioacetamide in rats in vivo, indicating that it might exert a direct effect on rat HSCs.

New developments in the chemistry and biology of the bioactive constituents of Tanshen

Tanshen, the rhizome of Salvia miltiorrhiza Bunge, has been used in Chinese traditional medicine (TCM) for multiple therapeutic remedies. The major constituents of Tanshen include water-soluble phenolic acids and lipophilic tanshinones. Phenolic acids possess antioxidant and anticoagulant activities, whereas tanshinones show antibacterial, antioxidant, and antineoplastic activities. This review will focus on recent developments concerning the chemical constituents of Tanshen and their biological activities. These chemical and biological studies continue to increase our understanding about a scientific basis for the traditional clinical use of Tanshen and can also contribute to the development of new drug candidates. Recently, in the author's laboratory, a new compound, neo-tanshinlactone, was discovered to have potent selective antibreast cancer activity. This compound might serve as a lead for developing promising antibreast cancer clinical trials candidates.

The role and regulation of hepatic stellate cell apoptosis in reversal of liver fibrosis

Liver fibrosis and its end-stage disease cirrhosis are major world health problems arising from chronic injury of the liver by a variety of etiological factors including viruses, alcohol and drug abuse, the metabolic syndrome, autoimmune disease and hereditary disorders of metabolism. Fibrosis is a progressive pathological process in which wound-healing myofibroblasts of the liver respond to injury by promoting replacement of the normal hepatic tissue with a scar-like matrix composed of cross-linked collagen. Until recently it was believed that this process was irreversible. However emerging experimental and clinical evidence is starting to show that even cirrhosis is potentially reversible. Key to this is the discovery that reversion of fibrosis is accompanied by clearance of hepatic stellate cells (HSC) by apoptosis. Furthermore, proof-of-concept studies in rodents have demonstrated that experimental augmentation of HSC apoptosis will promote the resolution of fibrosis. Consequently there is now considerable interest in determining the molecular events that regulate HSC apoptosis and the discovery of drugs that will stimulate HSC apoptosis in a selective manner. This review will consider the regulatory role played by growth factors (e.g. NGF, IGF-1, TGFbeta), death receptor ligands (TRAIL, FAS), components and regulators of extracellular matrix (integrins, collagen, matrix metalloproteinases and their tissue inhibitors) and signal transduction proteins and transcription factors (Rho/Rho kinase, Jun N-terminal Kinase (JNK), IkappaKinase (IKK), NF-kappa B). The potential for known pharmacological agents such as gliotoxin, sulfasalazine, benzodiazepine ligands, curcumin and tanshinone I to induce HSC apoptosis and therefore to be used therapeutically will be explored.

Aloe emodin-induced apoptosis in t-HSC/Cl-6 cells involves a mitochondria-mediated pathway

The aim of our study was to clarify the apoptosis pathway induced by aloe emodin, an hydroxyanthraquinone present in aloe vera leaves, in rat hepatic stellate cells transformed by simian virus 40 (t-HSC/Cl-6), which retain the features of activated rat stellate cells. Apoptosis was determined by DNA fragmentation, caspase activity assay and western blotting analysis. Treatment of t-HSC/Cl-6 cells with 12.5, 25, or 50 microM aloe emodin inhibited t-HSC/Cl-6 cell viability in a dose- and time-dependent manner. The induction of apoptosis by aloe emodin was confirmed by typical DNA ladder formation and annexin v-propidium iodide flow-cytometric analysis. Aloe emodin treatment of t-HSC/Cl-6 cells caused activation of caspase-3 and caspase-9, detected with a caspase activity assay, although no change was observed in caspase-8 activity. Western blotting showed caspase-3 and caspase-9 active forms and the subsequent proteolytic cleavage of poly(ADP-ribose) polymerase. Aloe emodin induced mitochondrial membrane depolarization. Our data also show that cytochrome c increased in the cytosol but decreased in the mitochondria in a time-dependent manner. Increased Bax and unchanged Bcl-2 levels resulted in an increased Bax/Bcl-2 ratio. Thus, our research provides evidence that aloe emodin-induced apoptosis involves a mitochondria-associated apoptosis pathway.

Role of stress-activated MAP kinase P38 in cisplatin- and DTT-induced apoptosis of the esophageal carcinoma cell line Eca109

AIM: To study the role of P38 kinase in esophageal cancer cell apoptosis induced by genotoxin, cisplatin and the unfolded protein response (UPR) inducer, dithiothreitol (DTT).

METHODS: Esophageal carcinoma cell line Eca109 was cultured in RPMI 1640 medium to 70% confluency and treated with either cisplatin, DTT, or cisplatin plus DTT in the presence or absence of P38 inhibitor, SB203580. The untreated cells served as the control. The esophageal carcinoma cell apoptosis was detected by agarose gel DNA ladder analysis and quantified by flow cytometry. The P38 phosphorylation was detected by immunohis-tochemistry using antibodies specific to phosphorylated P38 protein.

RESULTS: (1) Both cisplatin and DTT induced apoptosis in the esophageal cancer cell line Eca109 as shown by DNA ladder formation; (2) As detected by antibodies specific for the phosphorylated P38 protein (p-P38), both cisplatin and DTT treatments activated the stress-activated enzyme, MAP kinase P38. The number of positive cells was about 50% for the treatment groups, comparing to that of 10% for untreated group. DTT treatment, but not cisplatin treatment, induces nuclear localization of p-P38; (3) As measured by flow cytometry, inhibition of P38 activity by SB203580 blocks DTT- and cisplatin-induced apoptosis. The rates for DTT, cisplatin, and DTT plus cisplatin-induced apoptosis were 16.8%, 17.1%, and 21.4%, respectively. Addition of the SB compound during the incubation reduced the apoptotic rate to about 7.6% for all the treatment groups, suggesting that P38 activation is essential for cisplatin- and DTT-induced apoptosis in Eca109 cells.

CONCLUSION: (1) Both DTT and cisplatin were able to induce apoptosis in esophageal cancer cell line Eca109; (2) P38 MAP kinase is essential for DTT- and cisplatin-induced apoptosis in Eca109 cells; (3) P38 activation may be the common signaling component relaying the multiple upstream signaling events to the downstream cell death program.

Efficacy of Chinese medicine Yi-gan-kang granule in prophylaxis and treatment of liver fibrosis in rats

AIM

To investigate the efficacy of a Chinese medicine, Yi-gan-kang granule (granules for benefiting the liver), in prophylaxis and treatment of liver fibrosis in rats and its possible mechanism.

METHODS

One hundred and forty Sprague-Dawley rats were randomly divided into seven groups (20 each): group 1, blank control group without any interference during the study; group 2, CCl4-induced liver fibrosis group; group 3, pig serum-induced liver fibrosis group; group 4, prophylaxis group of CCl4-induced liver fibrosis by Yi-gan-kang; group 5, prophylaxis group of pig serum-induced liver fibrosis by Yi-gan-kang; group 6, treatment group of CCl4-induced liver fibrosis by Yi-gan-kang; group 7, treatment group of CCl4-induced liver fibrosis by Yi-gan-kang. At wk 6, 10, 14 and 20 (baseline for CCl4 or big serum induction), five rats in each group were anesthetized and their livers were removed for pathological studies including immunohistochemical studies for alpha-SMA, type I collagen and in situ hybridization of tissue inhibitor of metalloproteinase-1 (TIMP-1) mRNA of hepatic stellate cells (HSCs). Anti-lipid peroxidation in isolated mitochondria and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) colorimetric assay for proliferation and terminal deoxynucleotidyl transferase-medicated dUTP-biotin nick end-labeling (TUNEL), flow cytometry and electron microscopy for apoptosis in isolated HSCs were also studied.

RESULTS

The mean number of pseudolobuli at wk 10, 14 and 20 in the prophylaxis group was significantly less than that in the control group (P<0.05 or 0.01). The effect of prophylaxis at wk 14 in CCl4 rats and at wk 10 in pig serum-induced rats was much better than that of treatment group (P<0.01). The thickness (in microm) of fibers both in pig serum-induced prophylaxis and in treatment groups at wk 14 and 20 was significantly less than that in control group (P<0.05). The number of fibers both in prophylaxis and in treatment groups from wk 10 or 14 to 20 was significantly less than that in control group (P<0.05 or P<0.01). The tissue HSC positive rates of type I collagen, alpha-SMA and TIMP-1 mRNA, which represented the active phenotype of HSCs in tissues, remained very high from wk 6 to the end of model making in control group. While in prophylaxis group, they were at a relatively low level. In treatment group, there was a gradual decreasing trend. Time- and dose-dependent effects of anti-lipid peroxidation on isolated mitochondria, cell proliferation and apoptosis in cultured HSCs were also observed during the study.

CONCLUSION

Yi-gan-kang can effectively inhibit or inverse the course of liver fibrogenesis in CCl4- and pig serum-induced rat models.

Molecular mechanisms of inhibitory activities of tanshinones on Lipopolysaccharide-lnduced nitric oxide generation in RAW 264.7 cells

The effects of four tanshinones isolated from Tanshen (the root of Salvia miltiorrhiza Bunge, Labiatae) were tested for their inhibition of nitric oxide production in macrophage cells, and the underlying molecular mechanisms studied. Of the four tanshinones used, 15, 16-dihydrotanshinone-I, tanshinone-IIA and cryptotanshinone, but not tanshinone I, demonstrated significant inhibition of the LPS-induced nitric oxide production in RAW 264.7 cells, with calculated IC50 values of 5, 8, and 1.5 microM, respectively. Tanshinones exerted inhibitory activities on the LPS-induced nitric oxide production only when applied concurrently with LPS, and tanshinone-IIA and cryptotanshinone were found to inhibit LPS-induced NF-kappaB mobilization and extracellular-regulated kinase (ERK) activation, respectively. These results suggest that tanshinones inhibit LPS-induced nitric oxide generation by interfering with the initial stage of LPS-induced expression of certain genes. NF-kappaB and ERK could be the molecular targets for tanshinones for the inhibition of LPS-induced nitric oxide production in macrophage cells.