Rhein triggers apoptosis via induction of endoplasmic reticulum stress, caspase-4 and intracellular calcium in primary human hepatic HL-7702 cells

Novel application of rhein and its prodrug diacerein for reversing cancer-related multidrug resistance through the dual inhibition of P-glycoprotein efflux and STAT3-mediated P-glycoprotein expression

Multidrug resistance (MDR) is a multifactorial issue in cancer treatment. Drug efflux transporters, particularly P-glycoprotein (P-gp), are major contributors to such resistance. In the present study, we evaluated the P-gp-inhibiting and MDR-reversing effects of two compounds, namely rhein, an anthraquinone, and diacerein, the acetylated prodrug of rhein. ABCB1/Flp-In-293 was used as a model for investigating the related molecular mechanisms, and the multi-drug-resistant cancer cell line KB/VIN was used as a platform for evaluating the reversal of MDR0. The results indicated that at a concentration of 2.5 μM, both diacerein and rhein significantly inhibited P-gp efflux function. They also downregulated P-gp expression by interacting with the signal transducer and activator of transcription 3. Further investigation of the inhibitory mechanism of these compounds revealed that both stimulated P-gp ATPase activity dose dependently and engaged in the noncompetitive inhibition of rhodamine 123 efflux. Furthermore, rhein was revealed to be a potent reverser of MDR in cancer, and the combination of 30 μM rhein and 1000 nM vincristine exerted a strong synergistic effect, achieving a high combination index (CI) of 0.092. Diacerein demonstrated potential applications as a selective cytotoxic agent against multi-drug-resistant cancer cells at a concentration of > 18.92 μM and as a mild MDR reverser at doses of < 10 μM. In conclusion, diacerein and rhein are potential candidates for P-gp inhibition and MDR reversal in cancer cells.

Induction of Apoptosis by Metabolites of Rhei Radix et Rhizoma (Da Huang): A Review of the Potential Mechanism in Hepatocellular Carcinoma

Liver cancer is a global disease with a high mortality rate and limited treatment options. Alternations in apoptosis of tumor cells and immune cells have become an important method for detailing the underlying mechanisms of hepatocellular carcinoma (HCC). Bcl-2 family, Caspase family, Fas and other apoptosis-related proteins have also become antagonistic targets of HCC. Da Huang (Rhei Radix et Rhizoma, RR), a traditional Chinese herb, has recently demonstrated antitumor behaviors. Multiple active metabolites of RR, including emodin, rhein, physcion, aloe-emodin, gallic acid, and resveratrol, can successfully induce apoptosis and inhibit HCC. However, the underlying mechanisms of these metabolites inhibiting the occurrence and development of HCC by inducing apoptosis is complicated owing to the multi-target and multi-pathway characteristics of traditional Chinese herbs. Accordingly, this article reviews the pathways of apoptosis, the relationship between HCC and apoptosis, the role and mechanism of apoptosis induced by mitochondrial endoplasmic reticulum pathway and death receptor pathway in HCC and the mechanism of six RR metabolites inhibiting HCC by inducing apoptosis.

The Phytochemical Rhein Mediates M6A-Independent Suppression of Adipocyte Differentiation

Adipogenesis is mediated by the complex gene expression networks involving the posttranscriptional modifications. The natural compound rhein has been linked to the regulation of adipogenesis, but the underlying regulatory mechanisms remain elusive. Herein, we systematically analyzed the effects of rhein on adipogenesis at both the transcriptional and posttranscriptional levels. Rhein remarkably suppresses adipogenesis in the stage-specific and dose-dependent manners. Rhein has been identified to inhibit fat mass and obesity-associated (FTO) demethylase activity. Surprisingly, side-by-side comparison analysis revealed that the rhein treatment and Fto knockdown triggered the differential gene regulatory patterns, resulting in impaired adipocyte formation. Specifically, rhein treatment mildly altered the transcriptome with hundreds of genes dysregulated. N⁶-methyladenosine (m⁶A) methylome profile showed that, although the supply of rhein induced increased m⁶A levels on a small subset of messenger RNAs (mRNAs), few of them showed dramatic transcriptional response to this compound. Moreover, the specific rhein-responsive mRNAs, which are linked to mitotic pathway, are barely methylated or contain m⁶A peaks without dramatic response to rhein, suggesting separate regulation of global m⁶A pattern and adipogenesis mediated by rhein. Further identification of m⁶A-independent pathways revealed a positive regulator, receptor expressing-enhancing protein 3 (REEP3), in guidance of adipogenesis. Hence, this study provides the mechanistic view of the cellular actions of rhein in the modulation of adipogenesis and identifies a potential novel target for obesity therapeutic research.

Anthraquinones as Potential Antibiofilm Agents Against Methicillin-Resistant Staphylococcus aureus

Biofilms formed by methicillin-resistant Staphylococcus aureus (MRSA) are one of the contributing factors to recurrent nosocomial infection in humans. There is currently no specific treatment targeting on biofilms in clinical trials approved by FDA, and antibiotics remain the primary therapeutic strategy. In this study, two anthraquinone compounds isolated from a rare actinobacterial strain Kitasatospora albolonga R62, 3,8-dihydroxy-l-methylanthraquinon-2-carboxylic acid (1) and 3,6,8-trihydroxy-1-methylanthraquinone-2-carboxylic acid (2), together with their 10 commercial analogs 3–12 were evaluated for antibacterial and antibiofilm activities against MRSA, which led to the discovery of two potential antibiofilm anthraquinone compounds anthraquinone-2-carboxlic acid (6) and rhein (12). The structure-activity relationship analysis of these anthraquinones indicated that the hydroxyl group at the C-2 position of the anthraquinone skeleton played an important role in inhibiting biofilm formation at high concentrations, while the carboxyl group at the same C-2 position had a great influence on the antibacterial activity and biofilm eradication activity. The results of crystal violet and methyl thiazolyl tetrazolium staining assays, as well as scanning electron microscope and confocal scanning laser microscopy imaging of compounds 6 and 12 treatment groups showed that both compounds could disrupt preformed MRSA biofilms possibly by killing or dispersing biofilm cells. RNA-Seq was subsequently used for the preliminary elucidation of the mechanism of biofilm eradication, and the results showed upregulation of phosphate transport-related genes in the overlapping differentially expressed genes of both compound treatment groups. Herein, we propose that anthraquinone compounds 6 and 12 could be considered promising candidates for the development of antibiofilm agents.

[Heat stress induces neuronal apoptosis by up-regulating endoplasmic reticulum stress pathway]

OBJECTIVE

To explore the role of endoplasmic reticulum stress in heat stress-induced apoptosis of human neuroblastoma SH-SY5Y cells.

OBJECTIVE

SH-SY5Y cells were incubated at 43 ℃ for 2 h followed by further culture at 37 ℃ for 0, 3 h, or 6 h. With the cells cultured at 37 ℃ as the control, the cells exposed to heat stress were examined for morphological changes under optical microscope and changes in cell viability using CCK-8 assay. Flow cytometry was performed for detecting apoptosis of the cells following heat stress, and intracellular Ca²⁺ level in the cells was determined using flow cytometry and immunofluorescence confocal microscopy. The mRNA expression levels of caspase-12, BIP and XBP-1 in the cells were detected using qRT-PCR, and the protein expressions of caspase-12, BIP, P-JNK, JNK and XBP-1 were examined using Western blotting. The effect of pretreatment with 4-PBA on cell apoptosis following heat stress was analyzed with Western blotting.

OBJECTIVE

SH-SY5Y cells showed obvious cell shrinkage immediately after the exposure to heat stress, followed then by gradual cell stretching over time. The cell viability decreased significantly after heat stress (P=0.001), and the intracellular Ca²⁺ level increased significantly at 0 h and gradually recovered the normal level at 3 and 6 h. Heat stress induced significant increase in the protein expression of cleaved caspase-3 and time-dependent increase of caspase-12 (P=0.002) and BIP (P=0.008) expression at both the protein and mRNA levels. The expression of P-JNK/JNK protein increased significantly at 0 h (P=0.003) followed by gradual decrease; the expression levels of XBP-1 protein and mRNA gradually decreased after heat stress (P=0.005, P=0.002). Pretreatment with 4-PBA significantly reduced the expression level of cleaved caspase-3 in SH-SY5Y cells following heat stress.

OBJECTIVE

Heat stress induces apoptosis of SH-SY5Y cells by triggering endoplasmic reticulum stress and the imbalance of intracellular calcium ion homeostasis.

Potential therapeutic compounds from traditional Chinese medicine targeting endoplasmic reticulum stress to alleviate rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease which affects about 0.5-1% of people with symptoms that significantly impact a sufferer's lifestyle. The cells involved in propagating RA tend to display pro-inflammatory and cancer-like characteristics. Medical drug treatment is currently the main avenue of RA therapy. However, drug options are limited due to severe side effects, high costs, insufficient disease retardation in a majority of patients, and therapeutic effects possibly subsiding over time. Thus there is a need for new drug therapies. Endoplasmic reticulum (ER) stress, a condition due to accumulation of misfolded proteins in the ER, and subsequent cellular responses have been found to be involved in cancer and inflammatory pathologies, including RA. ER stress protein markers and their modulation have therefore been suggested as therapeutic targets, such as GRP78 and CHOP, among others. Some current RA therapeutic drugs have been found to have ER stress-modulating properties. Traditional Chinese Medicines (TCMs) frequently use natural products that affect multiple body and cellular targets, and several medicines and/or their isolated compounds have been found to also have ER stress-modulating capabilities, including TCMs used in RA treatment by Chinese Medicine practitioners. This review encourages, in light of the available information, the study of these RA-treating, ER stress-modulating TCMs as potential new pharmaceutical drugs for use in clinical RA therapy, along with providing a list of other ER stress-modulating TCMs utilized in treatment of cancers, inflammatory diseases and other diseases, that have potential use in RA treatment given similar ER stress-modulating capacity.

TLR4-mediated pyroptosis in human hepatoma-derived HuH-7 cells induced by a branched-chain polyunsaturated fatty acid, geranylgeranoic acid

A branched-chain polyunsaturated fatty acid, geranylgeranoic acid (GGA; C_20:4), which is an endogenous metabolite derived from the mevalonate pathway in mammals, has been reported to induce cell death in human hepatoma cells. We have previously shown that the lipid-induced unfolded protein response (UPR) is an upstream cellular process for an incomplete autophagic response that might be involved in GGA-induced cell death. Here, we found that Toll-like receptor 4 (TLR4)-mediated pyroptosis in HuH-7 cells occurred by GGA treatment. The TLR4-specific inhibitor VIPER prevented both GGA-induced cell death and UPR. Knockdown of the TLR4 gene attenuated GGA-induced cell death significantly. Upon GGA-induced UPR, caspase (CASP) 4 (CASP4) was activated immediately and gasdermin D (GSDMD) was translocated concomitantly to the plasma membrane after production of the N-terminal fragment of GSDMD. Then, cellular CASP1 activation occurred following a second gradual up-regulation of the intracellular Ca²⁺ concentration, suggesting that GGA activated the inflammasome. Indeed, the mRNA levels of NOD-like receptor family pyrin domain containing 3 (NLRP3) and interleukin-1 β (IL1B) genes were up-regulated dramatically with translocation of cytoplasmic nuclear factor-κB (NF-κB) to nuclei after GGA treatment, indicating that GGA induced priming of the NLRP3 inflammasome through NF-κB activation. GGA-induced up-regulation of CASP1 activity was blocked by either oleic acid, VIPER, MCC950 (a selective inhibitor of the NLRP3 inflammasome), or CASP4-specific inhibitor peptide cotreatment. Pyroptotic cell death was also confirmed morphologically by bleb formation in time-series live cell imaging of GGA-treated cells. Taken together, the present results strongly indicate that GGA causes pyroptotic cell death in human hepatoma-derived HuH-7 via TLR4 signalling.

Network Pharmacology-Based Study on the Molecular Biological Mechanism of Action for Qingdu Decoction against Chronic Liver Injury

Background

Qingdu Decoction (QDD) is a traditional Chinese medicine formula for treating chronic liver injury (CLI). Materials and methods. A network pharmacology combining experimental validation was used to investigate potential mechanisms of QDD against CLI. We firstly screened the bioactive compounds with pharmacology analysis platform of the Chinese medicine system (TCMSP) and gathered the targets of QDD and CLI. Then, we constructed a compound-target network and a protein-protein interaction (PPI) network and enriched core targets in Kyoto Encyclopedia of Genes and Genomes (KEGG) signaling pathways. At last, we used a CLI rat model to confirm the effect and mechanism of QDD against CLI. Enzyme-linked immunosorbent assay (ELISA), western blot (WB), and real-time quantitative polymerase chain reaction (RT-qPCR) were used.

Results

48 bioactive compounds of QDD passed the virtual screening criteria, and 53 overlapping targets were identified as core targets of QDD against CLI. A compound-CLI related target network containing 94 nodes and 263 edges was constructed. KEGG enrichment of core targets contained some pathways related to CLI, such as hepatitis B, tumor necrosis factor (TNF) signaling pathway, apoptosis, hepatitis C, interleukin-17 (IL-17) signaling pathway, and hypoxia-inducible factor (HIF)-1 signaling pathway. Three PPI clusters were identified and enriched in hepatitis B and tumor necrosis factor (TNF) signaling pathway, apoptosis and hepatitis B pathway, and peroxisome pathway, respectively. Animal experiment indicated that QDD decreased serum concentrations of alanine aminotransferase (ALT), aspartate aminotransferase (AST), endotoxin (ET), and IL-17 and increased prothrombin time activity (PTA) level. WB and RT-qPCR analyses indicated that, compared with the model group, the expression of cysteinyl aspartate specific proteinase-9 (caspase-9) protein, caspase-3 protein, B-cell lymphoma-2 associated X protein (Bax) mRNA, and cytochrome c (Cyt c) mRNA was inhibited and the expression of B-cell lymphoma-2 (Bcl-2) mRNA was enhanced in the QDD group.

Conclusions

QDD has protective effect against CLI, which may be related to the regulation of hepatocyte apoptosis. This study provides novel insights into exploring potential biological basis and mechanisms of clinically effective formula systematically.

Dihydroartemisinin induces ER stress-dependent apoptosis of Echinococcus protoscoleces in vitro

In this study, we investigated the effect of dihydroartemisinin on Echinococcus protoscoleces and explored the role of endoplasmic reticulum stress in this process. Echinococcus protoscoleces were collected and cultured in RPMI 1640 medium. Changes in the expressions of glucose-regulated protein 78 (GRP-78), caspase-12, and C/EBP homologous protein (CHOP) were assessed through confocal immunofluorescence and western blot analysis. Cell viability and morphological changes were observed under a light microscope. The ultrastructure of protoscoleces was observed by scanning electron microscopy and transmission electron microscopy. Caspase-3 activity was detected using an enzyme assay kit. After dihydroartemisinin treatment, the protoscoleces showed loss of viability, and morphological changes including soma contraction, blebs formation, hooks loss, microtrichia destruction, and development of lipid droplets was observed. The levels of caspase-12 and CHOP were increased within 2 days of dihydroartemisinin treatment. However, the levels of GRP-78, caspase-12, and CHOP were decreased in 4 days. Furthermore, caspase-3 activity was increased after treatment with different concentrations of dihydroartemisinin. Dihydroartemisinin can induce apoptosis in protoscoleces via the ER stress-caspase-3 apoptotic pathway in vitro. These results indicate that dihydroartemisinin is a potentially valuable therapeutic agent against echinococcosis.

In vivo hepatotoxicity screening of different extracts, components, and constituents of Polygoni Multiflori Thunb. in zebrafish (Danio rerio) larvae

Polygonum multiflorum Thunb. (PM) is a traditional Chinese medicine, commonly used to treat a variety of diseases. However, the hepatotoxicity associated with PM hampers its clinical application and development. In this study, we refined the zebrafish hepatotoxicity model with regard to the following endpoints: liver size, liver gray value, and the area of yolk sac. The levels of alanine aminotransferase, aspartate transaminase, albumin, and microRNAs-122 were evaluated to verify the model. Subsequently, this model was used to screen different extracts, components, and constituents of PM, including 70 % EtOH extracts of PM, four fractions from macroporous resin (components A, B, C, and D), and 19 compounds from component D. We found that emodin, chrysophanol, emodin-8-O-β-D-glucopyranoside, (cis)-emodin-emodin dianthrones, and (trans)-emodin-emodin dianthrones showed higher hepatotoxicity compared to other components in PM, whereas polyphenols showed lower hepatotoxicity. To the best of our knowledge, this study is the first to identify that dianthrones may account for the hepatotoxicity of PM. We believe that these findings will be helpful in regulating the hepatotoxicity of PM.

What we already know about rhubarb: a comprehensive review

Rhubarb (also named Rhei or Dahuang), one of the most ancient and important herbs in traditional Chinese medicine (TCM), belongs to the Rheum L. genus from the Polygonaceae family, and its application can be traced back to 270 BC in "Shen Nong Ben Cao Jing". Rhubarb has long been used as an antibacterial, anti-inflammatory, anti-fibrotic and anticancer medicine in China. However, for a variety of reasons, such as origin, variety and processing methods, there are differences in the effective components of rhubarb, which eventually lead to decreased quality and poor efficacy. Additionally, although some papers have reviewed the relationship between the active ingredients of rhubarb and pharmacologic actions, most studies have concentrated on one or several aspects, although there has been great progress in rhubarb research in recent years. Therefore, this review aims to summarize recent studies on the geographic distribution, taxonomic identification, pharmacology, clinical applications and safety issues related to rhubarb and provide insights into the further development and application of rhubarb in the future.

Apoptosis as an underlying mechanism in lymphocytes induced by riboflavin and ultraviolet light

Riboflavin plus UV light pathogen reduction technology (RF-PRT) is an effective method for inactivating donor-derived leukocytes (DDLs) in blood components. Literature data have shown that reactive oxygen species (ROS) increased in lymphocytes after RF-PRT treatment. Sustained high levels of ROS may abolish the endogenous antioxidant system, leading to damage to proteins, lipids, and nucleic acids, resulting in cell apoptosis. Nevertheless, whether riboflavin plus UV light can trigger leukocyte apoptosis remains obscure. In this study, a pool-and-split design, ABO/D-matched lymphocytes treated with RF-PRT or UV light or left untreated. After treatment, the level of ROS and intracellular calcium were measured in samples. Changes in the protein expression of cleaved PARP, Bax, and Bcl-2 and the activities of caspase-3 and caspase-9 were determined by immunoblot analysis or luminometer, respectively. Cell apoptosis was evaluated by flow cytometry. The effect of ROS on apoptosis was assessed. The RF-PRT treatment significantly augmented ROS production, intracellular calcium concentration. The pro-apoptotic proteins expression levels of Bax, but did not the anti-apoptotic protein Bcl-2, were markedly increased after the RF-PRT treatment. Furthermore, the percentage of apoptotic cells was increased in RF-PRT-treated lymphocytes compared to UV-treated cells or untreated cells. Moreover, the inhibition of ROS generation partially neutralized the apoptosis effects of riboflavin plus UV treatment. These findings revealed that RF-PRT-treated lymphocytes significantly increase the proportion of apoptotic cells by promoting ROS generation delineation of the biochemical processes influenced by RF-PRT are a necessary step to provide novel insights into the riboflavin pathogen inactivation technology.

Evaluation of intestinal permeation enhancement with carboxymethyl chitosan-rhein polymeric micelles for oral delivery of paclitaxel

Polymeric micelles (PMs) are currently under investigation as potential nanocarriers for oral administration of paclitaxel (PTX). Previously, we developed amphiphilic carboxymethyl chitosan-rhein (CR) conjugate for oral delivery of PTX. PTX-loaded CR PMs exhibited a homogeneous and small size (<200 nm) with a drug loading capacity (DL) of 35.46 ± 1.07%. However, The absorption parameters of PTX using CR PMs have not been studied before. Here, we evaluated the intestinal permeation of CR PMs by in situ intestinal absorption experiments. PTX-loaded CR PMs enhanced the absorption of PTX in the intestine without causing significant intestinal villi injury. Compared to the P-glycoprotein (P-gp) inhibition of verapamil, the transport mechanism of CR PMs across intestinal epithelial cells may bypass P-gp efflux. Caco-2 cell uptake assays also confirmed that CR PMs can be taken up into the enterocyte as whole and independent of P-gp. Local biodistribution evaluation showed that fluorescence-labeled CR PMs were absorbed into the intestinal villi. In vivo bioimaging of tumor-bearing mice verified a significant portion of CR PMs were intactly absorbed through the intestine, then distributed and accumulated at the tumor site. For their significant intestinal permeation enhancement, CR PMs might be considered as promising oral delivery carriers for PTX and other water-insoluble drugs.

Herb-Induced Liver Injury: Phylogenetic Relationship, Structure-Toxicity Relationship, and Herb-Ingredient Network Analysis

Currently, hundreds of herbal products with potential hepatotoxicity were available in the literature. A comprehensive summary and analysis focused on these potential hepatotoxic herbal products may assist in understanding herb-induced liver injury (HILI). In this work, we collected 335 hepatotoxic medicinal plants, 296 hepatotoxic ingredients, and 584 hepatoprotective ingredients through a systematic literature retrieval. Then we analyzed these data from the perspectives of phylogenetic relationship and structure-toxicity relationship. Phylogenetic analysis indicated that hepatotoxic medicinal plants tended to have a closer taxonomic relationship. By investigating the structures of the hepatotoxic ingredients, we found that alkaloids and terpenoids were the two major groups of hepatotoxicity. We also identified eight major skeletons of hepatotoxicity and reviewed their hepatotoxic mechanisms. Additionally, 15 structural alerts (SAs) for hepatotoxicity were identified based on SARpy software. These SAs will help to estimate the hepatotoxic risk of ingredients from herbs. Finally, a herb-ingredient network was constructed by integrating multiple datasets, which will assist to identify the hepatotoxic ingredients of herb/herb-formula quickly. In summary, a systemic analysis focused on HILI was conducted which will not only assist to identify the toxic molecular basis of hepatotoxic herbs but also contribute to decipher the mechanisms of HILI.

Metformin induces TPC-1 cell apoptosis through endoplasmic reticulum stress-associated pathways in vitro and in vivo

Thyroid cancer is among the most common types of malignant tumor of the endocrine system. The role of metformin in the inhibition of cancer cell proliferation and induction of apoptosis is widely accepted. The present study explored the effect and the underlying mechanisms of metformin on human thyroid cancer TPC‑1 cells. Following treatment of TPC‑1 cells with different concentrations of metformin, cell proliferation and apoptosis were analyzed by cell counting kit‑8 (CCK‑8) assay and flow cytometry, respectively. Reverse transcription‑quantitative PCR and western blotting were used to detect alterations in the mRNA and protein expression levels, respectively, for heat shock protein family A member 5 (HSPA5, also known as Bip), DNA damage‑inducible transcript 3 (DDIT3, also known as CHOP) and caspase‑12. The results demonstrated that treatment with metformin inhibited proliferation and induced apoptosis in a concentration and time‑dependent manner. In addition, treatment with metformin increased the expression of Bip, CHOP and caspase‑12 in vitro, activating endoplasmic reticulum (ER) stress. Thapsigargin treatment enhanced the apoptosis induced by metformin. Inhibition of ER stress by 4‑phenylbutyrate reversed the metformin‑induced apoptosis. Finally, treatment with metformin inhibited thyroid cancer growth and increased the expression of Bip and CHOP in a TPC‑1 cell xenograft model. These results indicated that metformin increased the apoptotic rate of thyroid cancer cells via ER stress‑associated mechanisms.

Preparation and evaluation of carboxymethyl chitosan-rhein polymeric micelles with synergistic antitumor effect for oral delivery of paclitaxel

An amphiphilic carboxymethyl chitosan-rhein (CR) conjugate was prepared, characterized, and evaluated as a potential carrier material for oral delivery of paclitaxel (PTX). CR conjugate self-assembled in aqueous environment into CR polymeric micelles (CR PMs). The drug loading capacity and entrapment efficiency of PTX-loaded CR PMs were 35.24 ± 1.58% and 86.99 ± 12.26%, respectively. Pharmacokinetic results indicate that PTX-loaded CR PMs could significantly enhance the oral bioavailability of PTX. Confocal imaging of intestinal sections verified many of CR PMs were absorbed as whole through the intestinal membrane. The cytotoxicity assays in Caco-2 cells and in vivo antitumor efficacy showed that PTX-loaded CR PMs had a stronger antitumor efficacy. A synergistic antitumor effect between CR conjugate and PTX was proven in MCF-7 cells and antitumor efficacy studies. The investigation of CR conjugate developed in this study showed that CR PMs are promising for oral delivery of water-insoluble antitumor drugs.

Preclinical Pharmacokinetics of Scoparone, Geniposide and Rhein in an Herbal Medicine Using a Validated LC-MS/MS Method

The herbal formula Yin-Chen-Hao-Tang has been reported to have anti-fibrosis properties. The aim of this study was to reveal the pharmacokinetic characteristics of bioactive compounds in this herbal formula. A new high-performance liquid chromatography-tandem mass spectrometry method was developed and validated for simultaneous determination of scoparone, geniposide and rhein in rat plasma. A pharmaceutical herbal powder was administered to rats at doses of 1 g/kg and 3 g/kg orally. The method showed excellent linearity (r² > 0.999) and validation was successfully conducted for the pharmacokinetic study. The results show that the C_max values and areas under the curve of scoparone, geniposide and rhein were higher and not proportional to the dose in rat plasma, while the T_max and half-life values were consistent in the group that received 1 g/kg. The clearance of the higher dose (3 g/kg) did not decrease proportionally to that of the low dose. The results showed the nonlinear pharmacokinetic properties of scoparone, geniposide and rhein in Yin-Chen-Hao-Tang that suggested possible accumulation of bioactive compounds through oral administration. This pharmacokinetic study reveals that an increased dose of this herbal formula would largely increase the maximum concentration and bioavailability of scoparone, geniposide and rhein.

Detection of genetic variants between different Polish Landrace and Puławska pigs by means of RNA-seq analysis

Variant calling analysis based on RNA sequencing data provides information about gene variants. RNA-seq is cheaper and faster than is DNA sequencing. However, it requires individual hard filters during data processing due to post-transcriptional modifications such as splicing and RNA editing. In the present study, RNA-seq transcriptome data on two Polish pig breeds (Puławska, PUL, n = 8, and Polish Landrace, PL, n = 8) were included. The pig breeds are significantly different with regard to meat qualities such as texture, water exudation, growth traits and fat content in carcasses. A total of 2451 significant mutations were identified by a chi square tests, and functional analysis was carried out using Panther, KEGG and Kobas. Interesting missense gene variants and mutations located in regulatory regions were found in a few genes related to fatty acid metabolism and lipid storage such as ACSL5, ALDH3A2, FADS1, SCD, PLA2G12A and ATGL. A validation of mutational influences on pig traits was performed for ALDH3A2, ATGL, PLA2G12A and MYOM1 variants using association analysis including 215 pigs of the PL and PUL breeds. The ALDH3A2ENSSSCT00000019636.2:c.470T>C polymorphism was found to affect the weight of the ham and loin eye area. In turn, an ENSSSCT00000004091.2:c.2836G>A MYOM1 mutation, which could be implicated in myofibrillar network organisation, had an effect on meatiness and loin texture parameters. The study aimed to estimate the usefulness of RNA-seq results for a purpose other than differentially expressed gene analysis. The analysis performed indicated interesting gene variants that could be used in the future as markers during selection.

Rhein Induces Cell Death in HepaRG Cells through Cell Cycle Arrest and Apoptotic Pathway

Rhein, a naturally occurring active anthraquinone found abundantly in various medicinal and nutritional herbs, possesses a wide spectrum of pharmacological effects. Furthermore, previous studies have reported that rhein could induce hepatotoxicity in rats. However, its cytotoxicity and potential molecular mechanisms remain unclear. Therefore, the present study aimed to investigate the cytotoxicity of rhein on HepaRG cells and the underlying mechanisms of its cytotoxicity. Our results demonstrate, by 3-(4,5-dimethyl thiazol-2-yl-)-2,5-diphenyl tetrazolium bromide (MTT) and Annexin V-fluoresce isothiocyanate (FITC)/propidium iodide (PI) double-staining assays, that rhein significantly inhibited cell viability and induced apoptosis in HepaRG cells. Moreover, rhein treatment resulted in the generation of reactive oxygen species (ROS), loss of mitochondrial membrane potential (MMP), and S phase cell cycle arrest. The results of Western blotting showed that rhein treatment resulted in a significant increase in the protein levels of Fas, p53, p21, Bax, cleaved caspases-3, -8, -9, and poly(ADP-ribose)polymerase (PARP). The protein expression of Bcl-2, cyclin A, and cyclin-dependent kinase 2 (CDK 2) was decreased. In conclusion, these results suggest that rhein treatment could inhibit cell viability of HepaRG cells and induce cell death through cell cycle arrest in the S phase and activation of Fas- and mitochondrial-mediated pathways of apoptosis. These findings emphasize the need to assess the risk of exposure for humans to rhein.

Proscillaridin A Promotes Oxidative Stress and ER Stress, Inhibits STAT3 Activation, and Induces Apoptosis in A549 Lung Adenocarcinoma Cells

Cardiac glycosides are natural compounds used for the treatment of cardiovascular disorders. Although originally prescribed for cardiovascular diseases, more recently, they have been rediscovered for their potential use in the treatment of cancer. Proscillaridin A (PSD-A), a cardiac glycoside component of Urginea maritima, has been reported to exhibit anticancer activity. However, the cellular targets and anticancer mechanism of PSD-A in various cancers including lung cancer remain largely unexplored. In the present study, we found that PSD-A inhibits growth and induces apoptosis in A549 lung adenocarcinoma cells. The anticancer activity of PSD-A was found to be associated with the activation of JNK, induction of ER stress, mitochondrial dysfunction, and inhibition of STAT3 activation. PSD-A induces oxidative stress as evidenced from ROS generation, GSH depletion, and decreased activity of TrxR1. PSD-A-mediated ER stress was verified by increased phosphorylation of eIF2α and expression of its downstream effector proteins ATF4, CHOP, and caspases-4. PSD-A triggered apoptosis by inducing JNK (1/2) activation, increasing bax/bcl-2 ratio, dissipating mitochondrial membrane potential, and inducing cleavage of caspases and PARP. Further study revealed that PSD-A inhibits both constitutive and inducible STAT3 activations and decreases STAT3 DNA-binding activity. Moreover, PSD-A-mediated inhibition of STAT3 activation was found to be associated with increased SHP-1 expression, decreased phosphorylation of Src, and binding of PSD-A with STAT3 SH2 domain. Finally, STAT3 knockdown by shRNA inhibited growth and enhanced apoptotic efficacy of PSD-A. Taken together, the data suggest that PSD-A could be developed into a potential therapeutic agent against lung adenocarcinoma.

Rhein Induces Oxidative Stress and Apoptosis in Mouse Blastocysts and Has Immunotoxic Effects during Embryonic Development

Rhein, a glucoside chemical compound found in a traditional Chinese medicine derived from the roots of rhubarb, induces cell apoptosis and is considered to have high potential as an antitumor drug. Several previous studies showed that rhein can inhibit cell proliferation and trigger mitochondria-related or endoplasmic reticulum (ER) stress-dependent apoptotic processes. However, the side effects of rhein on pre- and post-implantation embryonic development remain unclear. Here, we show that rhein has cytotoxic effects on blastocyst-stage mouse embryos and induces oxidative stress and immunotoxicity in mouse fetuses. Blastocysts incubated with 5-20 μM rhein showed significant cell apoptosis, as well as decreases in their inner cell mass cell numbers and total cell numbers. An in vitro development assay showed that rhein affected the developmental potentials of both pre- and post-implantation embryos. Incubation of blastocysts with 5-20 μM rhein was associated with increased resorption of post-implantation embryos and decreased fetal weight in an embryo transfer assay. Importantly, in an in vivo model, intravenous injection of dams with rhein (1, 3, and 5 mg/kg body weight/day) for four days resulted in apoptosis of blastocyst-stage embryos, early embryonic developmental injury, and decreased fetal weight. Intravenous injection of dams with 5 mg/kg body weight/day rhein significantly increased the total reactive oxygen species (ROS) content of fetuses and the transcription levels of antioxidant proteins in fetal livers. Additional work showed that rhein induced apoptosis through ROS generation, and that prevention of apoptotic processes effectively rescued the rhein-induced injury effects on embryonic development. Finally, the transcription levels of the innate-immunity related genes, CXCL1, IL-1β and IL-8, were down-regulated in the fetuses of dams that received intravenous injections of rhein. These results collectively show that rhein has the potential to induce embryonic cytotoxicity and induce oxidative stress and immunotoxicity during the development of mouse embryos.