Inflammatory macrophages exacerbate neutrophil-driven joint damage through ADP/P2Y1 signaling in rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic autoimmune disease that primarily affects the joints and is associated with excessive immune cell infiltration. However, the complex interactions between the immune cell populations in the RA synovium remain unknown. Here, we demonstrate that inflammatory macrophages in the synovium exacerbate neutrophil-driven joint damage in RA through ADP/P2Y1 signaling. We show that extracellular ADP (eADP) and its receptors are obviously increased in synovial tissues of RA patients as well as collagen-induced arthritis (CIA) mice, and eADP enhances neutrophil infiltration into joints through macrophages producing the chemokine CXCL2, aggravating disease development. Accordingly, the arthritis mouse model had more neutrophils in inflamed joints following ADP injection, whereas P2Y1 deficiency and pharmacologic inhibition restored arthritis severity to basal levels, suggesting a dominant role of ADP/P2Y1 signaling in RA pathology. Moreover, cellular activity of ADP/P2Y1-mediated CXCL2 production was dependent on the Gαq/Ca2+-NF-κB/NFAT pathway in macrophages. Overall, this study reveals a non-redundant role of eADP as a trigger in the pathogenesis of RA through neutrophil recruitment and disrupted tissue homeostasis and function.

XB130 Deficiency Causes Congenital Hypothyroidism in Mice due to Disorganized Apical Membrane Structure and Function of Thyrocytes.

Background: Congenital hypothyroidism is often caused by genetic mutations that impair thyroid hormone (TH) production, resulting in growth and development defects. XB130 (actin filament associated protein 1 like 2) is an adaptor/scaffold protein that plays important roles in cell proliferation, migration, intracellular signal transduction, and tumorigenesis. It is highly expressed in thyrocytes, however, its function in the thyroid remains largely unexplored. Methods:Xb130-/- mice and their littermates were studied. Postnatal growth and growth hormone levels were measured, and responses to low or high-iodine diet, and levothyroxine treatment were examined. TH and thyrotropin in the serum and TH in the thyroid glands were quantified. Structure and function of thyrocytes in embryos and postnatal life were studied with histology, immunohistochemistry, immunofluorescence staining, Western blotting, and quantitative reverse transcription polymerase chain reaction. Results:Xb130-/- mice exhibited transient growth retardation postnatally, due to congenital hypothyroidism with reduced TH synthesis and secretion, which could be rescued by exogenous thyroxine supplementation. The thyroid glands of Xb130-/- mice displayed diminished thyroglobulin iodination and release at both embryonic and early postnatal stages. XB130 was found mainly on the apical membrane of thyroid follicles. Thyroid glands of embryonic and postnatal Xb130-/- mice exhibited disorganized apical membrane structure, delayed folliculogenesis, and abnormal formation of thyroid follicle lumina. Conclusion: XB130 critically regulates folliculogenesis by maintaining apical membrane structure and function of thyrocytes, and its deficiency leads to congenital hypothyroidism.

From a Designer Drug to the Discovery of Selective Cannabinoid Type 2 Receptor Agonists with Favorable Pharmacokinetic Profiles for the Treatment of Systemic Sclerosis.

Synthetic cannabinoids, as exemplified by SDB-001 (1), bind to both CB1 and CB2 receptors and exert cannabimimetic effects similar to (-)-trans-Δ9-tetrahydrocannabinol, the main psychoactive component present in the cannabis plant. As CB1 receptor ligands were found to have severe adverse psychiatric effects, increased attention was turned to exploiting the potential therapeutic value of the CB2 receptor. In our efforts to discover novel and selective CB2 receptor agonists, 1 was selected as a starting point for hit molecule identification and a class of 1H-pyrazole-3-carboxamide derivatives were thus designed, synthesized, and biologically evaluated. Systematic structure-activity relationship investigations resulted in the identification of the most promising compound 66 as a selective CB2 receptor agonist with favorable pharmacokinetic profiles. Especially, 66 treatment significantly attenuated dermal inflammation and fibrosis in a bleomycin-induced mouse model of systemic sclerosis, supporting that CB2 receptor agonists might serve as potential therapeutics for treating systemic sclerosis.

Generation and Characterization of Cytochrome P450 2J3/10 CRISPR/Cas9 Knockout Rat Model.

Cytochrome P450 2J2 (CYP2J2) enzyme attracts more attention because it not only metabolizes clinical drugs but also mediates the biotransformation of important endogenous substances and the regulation of physiologic function. Although CYP2J2 is very important, few animal models are available to study its function in vivo In particular, a CYP2J gene knockout (KO) rat model for drug metabolism and pharmacokinetics is not available. In this report, the CRISPR/Cas9 technology was used to delete rat CYP2J3/10, the orthologous genes of CYP2J2 in humans. The CYP2J3/10 KO rats were viable and fertile and showed no off-target effect. Compared with wild-type (WT) rats, the mRNA and protein expression of CYP2J3/10 in liver, small intestine, and heart of KO rats were completely absent. At the same time, CYP2J4 mRNA expression and protein expression were significantly decreased in these tissues. Further in vitro and in vivo metabolic studies of astemizole, a typical substrate of CYP2J, indicated that CYP2J was functionally inactive in KO rats. The heart function indexes of WT and KO rats were also measured and compared. The myocardial enzymes, including creatine kinase-muscle brain type (CK-MB), creatine kinase (CK), and CK-MB/CK ratio, of KO rats increased by nearly 140%, 80%, and 60%, respectively. In conclusion, this study successfully developed a new CYP2J3/10 KO rat model, which is a useful tool to study the function of CYP2J in drug metabolism and cardiovascular disease. SIGNIFICANCE STATEMENT: Human CYP2J2 is involved not only in clinical drug metabolism but also in the biotransformation of important endogenous substances. Therefore, it is very important to construct new animal models to study its function in vivo. This study successfully developed a new CYP2J knockout rat model by using CRISPR/Cas9 technology. This rat model provides a useful tool to study the role of CYP2J in drug metabolism and diseases.

Natural product corynoline suppresses melanoma cell growth through inducing oxidative stress.

Natural product corynoline is a unique isoquinoline alkaloid extracted from traditional Chinese medicine Corydalis bungeana Turcz, whereas its anticancer properties have not been investigated. In this study, we found that corynoline potently impairs the growth of melanoma cells, B16F10, and A375 in a concentration-dependent manner. Treatment of melanoma cells with corynoline results in G2 cell arrest accompanied by reduced cdc2 activation. Furthermore, corynoline triggers apoptosis of melanoma cells, which is associated with increased expression of Bax and cleaved caspase-3. Mechanistic study indicates that corynoline strongly induces reactive oxygen species (ROS) generation and subsequent DNA damage as evidenced by γ-H2AX accumulation. Notably, the effect of corynoline on melanoma cell cycle and apoptosis is abolished by a ROS scavenger N-acetyl cysteine (NAC), indicating a ROS-dependent mechanism. Finally, corynoline significantly inhibits in vivo B16F10 melanoma tumor growth accompanied by reduced expression of Ki-67 in tumor tissue. Taken together, our data suggest that corynoline suppresses melanoma cell growth in vitro and in vivo by inducing oxidative stress and represents a potential therapeutic agent for melanoma patients.

Determining the Drug-Like Properties of Ailanthone, a Novel Chinese Medicine Monomer with Anti-CRPC Activity.

Approximately 40% of compounds with therapeutic potential cannot be successfully developed into drugs owing to their poor pharmaceutical properties, emphasising the need to profile their drug-like properties as early as possible during preclinical development. This study aimed to evaluate the drug-like properties of ailanthone, a novel Chinese medicine monomer that was shown to have activity against castration-resistant prostate cancer tumour growth and metastasis in our previous study. The drug-like properties detected in the present study included effects on permeability, liver microsome stability, plasma protein binding rate, plasma stability, and human ether-à-go-go-related gene inhibition. Additionally, the following results were obtained: the efflux ratio of ailanthone was > 32 during permeability detection; the half-life and intrinsic clearance (Clint) in mouse, rat, and human liver microsomes were > 145 min and < 9.6 µL/min/mg protein, respectively. The Clint(liver) of ailanthone was < 38.0, < 17.3, and < 8.6 mL/min/kg body weight in mice, rats, and humans, respectively. The plasma protein binding percentage of ailanthone was 16.6 ± 4.2% in human plasma, with 62.5% remaining at 120 min after incubation. The IC50 value of ailanthone for the human ether-à-go-go-related gene channels was > 30 µM. Collectively, these results and those from our previous study indicate that the pharmacokinetic properties of ailanthone are suitable for the potential development of this compound as an oral or intravenous drug for the treatment of castration-resistant prostate cancer.

Design, synthesis and evaluation of phenylthiazole and phenylthiophene pyrimidindiamine derivatives targeting the bacterial membrane.

As the continuous rise in the incidence of antibiotic resistance, it is urgent to develop novel chemical scaffolds with antibacterial activities to control the spread of resistance to conventional antibiotics. In this study, a series of phenylthiazole and phenylthiophene pyrimidindiamine derivatives were designed and synthesized by modifying the hit compound (N2-isobutyl-N4-((4-methyl-2-phenylthiazol-5-yl)methyl) pyrimidine-2,4-diamine) and their antibacterial activities were evaluated both in vitro and in vivo. Among the tested compounds, compound 14g (N4-((5-(3-bromophenyl)thiophen-2-yl)methyl)-N2-isobutylpyrimidine-2,4-diamine) displayed the best antibacterial activities, which was not only capable of inhibiting E. coli and S. aureus growth at concentrations as low as 2 and 3 µg/mL in vitro, but also efficacious in a mice model of bacteremia in vivo. Unlike conventional antibiotics, compound 14g was elucidated to mainly destroy the bacterial cell membrane, with the dissipation of membrane potential and leakage of contents, ultimately leading to cell death. The destruction of cell structure is challenging to induce bacterial resistance, which suggested that compound 14g may be a kind of promising alternatives to antibiotics against bacteria.

Celastrol is a novel selective agonist of cannabinoid receptor 2 with anti-inflammatory and anti-fibrotic activity in a mouse model of systemic sclerosis.

BACKGROUND: Increasing evidence indicated that the cannabinoid receptors were involved in the pathogenesis of organ fibrogenesis. PURPOSE: The purpose of this study was to discover novel cannabinoid receptor 2 (CB2) agonist and assess the potential of CB2 activation in treating systemic sclerosis. METHODS: A gaussia princeps luciferase-based split luciferase complementation assay (SLCA) was developed for detection of the interaction between CB2 and ß-arrestin2. A library of 366 natural products was then screened as potential CB2 agonist using SLCA approach. Several GPCR functional assays, including HTRF-based cAMP assay and calcium mobilization were also utilized to evaluated CB2 activation. Bleomycin-induced experimental systemic sclerosis was used to assess the in vivo anti-fibrotic effects. Dermal thickness and collagen content were evaluated via H&E and sirius red staining. RESULTS: Celastrol was identified as a new agonist of CB2 by using SLCA. Furthermore, celastrol triggers several CB2-mediated downstream signaling pathways, including calcium mobilization, inhibition of cAMP accumulation, and receptor desensitization in a dose-dependent manner, and it has a moderate selectivity on CB1. In addition, celastrol exhibited the anti-inflammatory properties on lipopolysaccharide (LPS) treated murine Raw 264.7 macrophages and primary macrophages. Finally, we found that celastrol exerts anti-fibrotic effects in the bleomycin-induced systemic sclerosis mouse model accompanied by reduced inflammatory conditions. CONCLUSION: Taken together, celastrol is identified a novel selective CB2 agonist using a new developed arrestin-based SLCA, and CB2 activation by celastrol reduces the inflammatory response, and prevents the development of dermal fibrosis in bleomycin-induced systemic sclerosis mouse model.

Preclinical toxicology and toxicokinetic evaluation of ailanthone, a natural product against castration-resistant prostate cancer, in mice.

Ailanthone (AIL) has many biological activities including antimalarial, antiviral and anticancer. Our previous study also found that AIL targets p23 against castration-resistant prostate cancer. In this report, the preclinical safety of AIL was evaluated by acute toxicity, subacute toxicity and toxicokinetics in mice. In the acute toxicity study, the LD50 of AIL was 27.3 mg/kg, and severe pathological damages were mainly found in the liver and gastrointestinal tract. In the subacute toxicity study, mice were orally administered at doses of 2.5, 5 and 10 mg/kg for 28 days. The results showed the body weight of male mice in the 10 mg/kg dose group decreased, but that of female mice increased. Biochemical and histopathological analysis showed that AIL could cause steatohepatitis, splenomegaly, gastrointestinal mucosal damage and reproductive system abnormalities. In addition, AIL presented the reversible hematotoxicity. To determine the relationship between AIL toxicity and dose/exposure in vivo, toxicokinetics of AIL were carried out after a single oral dose of 15 mg/kg. The stomach was identified as the main target organ, followed by the intestine and kidney. On the basis of this study, the dose of 2.5 mg/kg had no adverse effect on mice. To sum up, this study is the first time to evaluate the systemic toxicity of AIL, which is useful for the further development of AIL.

Inactivating hepatitis C virus in donor lungs using light therapies during normothermic ex vivo lung perfusion.

Availability of organs is a limiting factor for lung transplantation, leading to substantial mortality rates on the wait list. Use of organs from donors with transmissible viral infections, such as hepatitis C virus (HCV), would increase organ donation, but these organs are generally not offered for transplantation due to a high risk of transmission. Here, we develop a method for treatment of HCV-infected human donor lungs that prevents HCV transmission. Physical viral clearance in combination with germicidal light-based therapies during normothermic ex-vivo Lung Perfusion (EVLP), a method for assessment and treatment of injured donor lungs, inactivates HCV virus in a short period of time. Such treatment is shown to be safe using a large animal EVLP-to-lung transplantation model. This strategy of treating viral infection in a donor organ during preservation could significantly increase the availability of organs for transplantation and encourages further clinical development.

Pharmacological inhibition of dihydroorotate dehydrogenase induces apoptosis and differentiation in acute myeloid leukemia cells.

Acute myeloid leukemia is a disorder characterized by abnormal differentiation of myeloid cells and a clonal proliferation derived from primitive hematopoietic stem cells. Interventions that overcome myeloid differentiation have been shown to be a promising therapeutic strategy for acute myeloid leukemia. In this study, we demonstrate that CRISPR/Cas9-mediated knockout of dihydroorotate dehydrogenase leads to apoptosis and normal differentiation of acute myeloid leukemia cells, indicating that dihydroorotate dehydrogenase is a potential differentiation regulator and a therapeutic target in acute myeloid leukemia. By screening a library of natural products, we identified a novel dihydroorotate dehydrogenase inhibitor, isobavachalcone, derived from the traditional Chinese medicine Psoralea corylifolia Using enzymatic analysis, thermal shift assay, pull down, nuclear magnetic resonance, and isothermal titration calorimetry experiments, we demonstrate that isobavachalcone inhibits human dihydroorotate dehydrogenase directly, and triggers apoptosis and differentiation of acute myeloid leukemia cells. Oral administration of isobavachalcone suppresses subcutaneous HL60 xenograft tumor growth without obvious toxicity. Importantly, our results suggest that a combination of isobavachalcone and adriamycin prolonged survival in an intravenous HL60 leukemia model. In summary, this study demonstrates that isobavachalcone triggers apoptosis and differentiation of acute myeloid leukemia cells via pharmacological inhibition of human dihydroorotate dehydrogenase, offering a potential therapeutic strategy for acute myeloid leukemia.

Effectiveness and mechanism of natural attenuation at a petroleum-hydrocarbon contaminated site.

This study applied an integrated method for evaluating the effectiveness and mechanism of natural attenuation (NA) of petroleum-hydrocarbon contaminated groundwater. Site groundwater and soil samples were analysed to characterize spatial and temporal variations in petroleum hydrocarbons, geochemical indicators, microbial diversity and isotopes. The results showed that the area of petroleum hydrocarbon contamination plume decreased almost 60% in four years, indicating the presence of natural attenuation. The 14C content and sequence analysis indicate that there are more relatively 'old' HCO3- that have been produced from petroleum hydrocarbons in the upgradient portion of the contaminated plume, confirming that intrinsic biodegradation was the major factor limiting spread of the contaminated plume. The main degradation mechanisms were identified as sulfate reduction and methanogenesis based on the following: (1) more SO42- have been consumed in the contamination source than downgradient, and the δ34S values in the resident SO42- were also more enriched in the contamination source, (2) production of more CH4 in the contamination source with the δ13C values for CH4 was much lower than that of CO2, and the fractionation factor was 1.030-1.046. The results of this study provide significant insight for applying natural attenuation and enhanced bioremediation as alternative options for remediation of petroleum-hydrocarbon contaminated sites.

Plant natural product plumbagin presents potent inhibitory effect on human cytochrome P450 2J2 enzyme.

BACKGROUND: Cytochrome P450 2J2 (CYP2J2) is not only highly expressed in many kinds of human tumors, but also promotes tumor cell growth via regulating the metabolism of arachidonic acids. CYP2J2 inhibitors can significantly reduce proliferation, migration and promote apoptosis of tumor cells by inhibiting epoxyeicosatrienoic acids (EETs) biosynthesis. Therefore screening CYP2J2 inhibitors is a significant way for the development of anti-cancer drug. PURPOSE: The aim of this study was to identify a new CYP2J2 inhibitor from fifty natural compounds obtained from plants. STUDY DESIGN: CYP2J2 inhibitor was screened from a natural compounds library and further the inhibitory manner and mechanism were evaluated. Its cytotoxicity against HepG2 and SMMC-7721 cell lines was also estimated. METHODS: The inhibitory effect was evaluated in rat liver microsomes (RLMs), human liver microsomes (HLMs) and recombinant CYP2J2 (rCYP2J2), using astemizole as a probe substrate and inhibitory mechanism was illustrated through molecular docking. The cytotoxicity was detected using SRB. RESULTS: In all candidates, plumbagin showed the strongest inhibitory effect on the CYP2J2-mediated astemizole O-demethylation activity. Further study revealed that plumbagin potently inhibited CYP2J2 activity with IC50 value at 3.82 µM, 3.37 µM and 1.17 µM in RLMs, HLMs and rCYP2J2, respectively. Enzyme kinetic studies showed that plumbagin was a mixed-type inhibitor of CYP2J2 in HLMs and rCYP2J2 with Ki value of 1.88 µM and 0.92 µM, respectively. Docking data presented that plumbagin interacted with CYP2J2 mainly through GLU 222 and ALA 223. Moreover, plumbagin showed strongly cytotoxic effects on hepatoma cell lines, such as HepG2 and SMMC-7721, with lower toxicity on rat primary hepatocytes. Plumbagin had no effect on the protein expression of CYP2J2 in HepG2 and SMMC-7721, while down-regulated the mRNA level of anti-apoptosis protein Bcl-2. CONCLUSION: This study found out a new CYP2J2 inhibitor plumbagin from fifty natural compounds. Plumbagin presented a potential of anti-cancer pharmacological activity.

Electrospun Micropatterned Nanocomposites Incorporated with Cu2S Nanoflowers for Skin Tumor Therapy and Wound Healing.

Surgical excision of skin cancers can hardly remove the tumor tissues completely and simultaneously result in cutaneous defects. To avoid tumor recurrence and heal the tumor-induced wounds, we designed a tissue engineering membrane possessing bifunctions of tumor therapy and skin tissue regeneration. The micropatterned nanocomposite membrane was successfully fabricated by incorporating Cu2S nanoflowers into biopolymer fibers via a modified electrospinning method. With uniformly embedded Cu2S nanoparticles, the membranes exhibited excellent and controllable photothermal performance under near-infrared irradiation, which resulted in high mortality (>90%) of skin tumor cells and effectively inhibited tumor growth in mice. Moreover, the membranes supported the adhesion, proliferation, and migration of skin cells as well as significantly stimulated angiogenesis and healed full-thickness skin defects in vivo. This proof-of-concept study offers a facile and reliable strategy for localized skin tumor therapy and tissue regeneration using bifunctional tissue engineering biomaterials, showing great promise for tumor-induced wound healing applications.

Comprehensive assessment of Cucurbitacin E related hepatotoxicity and drug-drug interactions involving CYP3A and P-glycoprotein.

BACKGROUND: Cucurbitacin E (CuE), a tetracyclic triterpenoid isolated from Cucurbitaceae, possesses many pharmacological activities especially anti-cancer. PURPOSE: The aim of this investigation was to comprehensively assess CuE related hepatotoxicity and potential drug-drug interactions involving CYP3A and P-glycoprotein (P-gp). STUDY DESIGN AND METHODS: Four common cytotoxicity assays (MTS, SRB, NRU and apoptosis assays) were used to evaluate the hepatotoxicity of CuE in human hepatocellular carcinoma HepG2 cells. Human and rat liver microsomes incubation system, Caco-2 transport model and 3D organoids model were used to investigate the effects of CuE on CYP3A and P-gp in vitro. The oral pharmacokinetics of indinavir was employed to evaluate the effects of CuE on CYP3A and P-gp in vivo. RESULTS: CuE induced the HepG2 apoptosis and exhibited acute cytotoxicity in MTS, SRB, and NRU assays with IC50 value at 15.98µM, 0.31µM, and 1.11µM, respectively. Moreover, CuE not only presented mechanism-based inhibition on human CYP3A4, but also decreased the efflux ratio of digoxin (P-gp substrate) across Caco-2 cell monolayers in vitro. Furthermore, CuE significantly inhibited the transport of Rh123 into 3D organoids, which was caused by the inhibition on P-gp. In Sprague-Dawley rat studies in vivo, acute administration of CuE significantly increased the maximum serum concentration (Cmax) and area under the concentration-time curve (AUC) of indinavir. In contrast, CuE treatment for three consecutive days significantly decreased indinavir Cmax and AUC in rats. CONCLUSION: These studies demonstrated that CuE has strong hepatotoxicity, and CuE presents potent inhibition on both CYP3A and P-gp activities in vitro. In animal in vivo studies, CuE induces CYP3A and P-gp after a long-term treatment but inhibits the activities of CYP3A and P-gp after an acute dosing. Therefore, CuE as a dual functional regulator of both CYP3A and P-gp may cause complex drug-drug interactions.

A Novel Model of P-Glycoprotein Inhibitor Screening Using Human Small Intestinal Organoids.

P-glycoprotein (P-gp), an important efflux transporter in intestine, regulates the bioavailability of orally taken drugs. To develop an in vitro model that preferably mimics the physiological microenvironment of human intestine, we employed the three-dimensionally (3D) cultured organoids from human normal small intestinal epithelium. It was observed that the intestinal crypts could efficiently form cystic organoid structure with the extension of culture time. Furthermore, the physiological expression of ABCB1 was detected at both mRNA and protein levels in cultured organoids. Rhodamine 123 (Rh123), a typical substrate of P-gp, was actively transported across 3D organoids and accumulated in the luminal space. This transport process was also inhibited by verapamil and mitotane. In summary, the above-mentioned model based on human small intestinal 3D organoids is suitable to imitate the small intestinal epithelium and could be used as a novel in vitro model especially for P-gp inhibitor screening.

3D printing of biomaterials with mussel-inspired nanostructures for tumor therapy and tissue regeneration.

Primary bone cancer brings patients great sufferings. To deal with the bone defects resulted from cancer surgery, biomaterials with good bone-forming ability are necessary to repair bone defects. Meanwhile, in order to prevent possible tumor recurrence, it is essential that the remaining tumor cells around bone defects are completely killed. However, there are few biomaterials with the ability of both cancer therapy and bone regeneration until now. Here, we fabricated a 3D-printed bioceramic scaffold with a uniformly self-assembled Ca-P/polydopamine nanolayer surface. Taking advantage of biocompatibility, biodegradability and the excellent photothermal effect of polydopamine, the bifunctional scaffolds with mussel-inspired nanostructures could be used as a satisfactory and controllable photothermal agent, which effectively induced tumor cell death in vitro, and significantly inhibited tumor growth in mice. In addition, owing to the nanostructured surface, the prepared polydopamine-modified bioceramic scaffolds could support the attachment and proliferation of rabbit bone mesenchymal stem cells (rBMSCs), and significantly promoted the formation of new bone tissues in rabbit bone defects even under photothermal treatment. Therefore, the mussel-inspired nanostructures in 3D-printed bioceramic exhibited a remarkable capability for both cancer therapy and bone regeneration, offering a promising strategy to construct bifunctional biomaterials which could be widely used for therapy of tumor-induced tissue defects.

Evaluation of the inhibition potential of plumbagin against cytochrome P450 using LC-MS/MS and cocktail approach.

Plumbagin (5-hydroxy-2-methyl-1,4-naphthoquinone), a natural naphthoquinone compound isolated from roots of Plumbago zeylanica L., has drawn a lot of attention for its plenty of pharmacological properties including antidiabetes and anti-cancer. The aim of this study was to investigate the effects of plumbagin on CYP1A2, CYP2B1/6, CYP2C9/11, CYP2D1/6, CYP2E1 and CYP3A2/4 activities in human and rat liver and evaluate the potential herb-drug interactions using the cocktail approach. All CYP substrates and their metabolites were analyzed using high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). Plumbagin presented non-time-dependent inhibition of CYP activities in both human and rat liver. In humans, plumbagin was not only a mixed inhibitor of CYP2B6, CYP2C9, CYP2D6, CYP2E1 and CYP3A4, but also a non-competitive inhibitor of CYP1A2, with Ki values no more than 2.16 µM. In rats, the mixed inhibition of CYP1A2 and CYP2D1, and competitive inhibition for CYP2B1, CYP2C11 and CYP2E1 with Ki values less than 9.93 µM were observed. In general, the relatively low Ki values of plumbagin in humans would have a high potential to cause the toxicity and drug interactions involving CYP enzymes.

TAT cell-penetrating peptide modulates inflammatory response and apoptosis in human lung epithelial cells.

Cell-penetrating peptides (CPPs) are commonly used as delivery vehicles for the introduction of a variety of macromolecules into cells. Trans-activator of transcription (TAT) is the most commonly used CPP and, as a delivery vehicle, is assumed to be biologically inert. In this study, we pretreated human lung epithelial cells with TAT prior to stimulation with phorbol 12,13-dibutyrate (PDBu), a protein kinase C (PKC) activator. Surprisingly, TAT alone inhibited the production of multiple cytokines induced by PKC activation. Furthermore, PKC activation-induced IκBα degradation was partially reduced by TAT. Moreover, TAT treatment alone induced apoptosis in a dose-dependent manner, influenced expression of several B cell lymphoma 2 (Bcl-2) family members and increased caspase 3 cleavage at a high dose. These findings suggest that TAT as a delivery vehicle should be used cautiously, as it may affect the inflammatory response, as well as signals related to apoptosis.

Investigation of cytochrome P450 inhibitory properties of maslinic acid, a bioactive compound from Olea europaea L., and its structure-activity relationship.

Maslinic acid (MA), the main pentacyclic triterpene of Olea europaea L. fruit, possesses a variety of pharmacological actions, including hypoglycemic, antioxidant, cardioprotective and antitumoral activities. Despite its importance, little is known about its effects on the cytochrome P450 (CYP) activity in both humans and animals. Therefore, the aim of this study was to investigate the effects of MA on the CYP 1A2, 2C9/11, 2D1/6, 2E1 and 3A2/4 activities by human and rat liver microsomes and specific CYP isoforms. In humans, MA only weakly inhibited CYP3A4 activity in human liver microsomes and specific CYP3A4 isoform with IC50 value at 46.1 and 62.3µM, respectively. In rats, MA also exhibited weak inhibition on CYP2C11, CYP2E1 and CYP3A2 activities with IC50 values more than 100µM. Enzyme kinetic studies showed that the MA was not only a competitive inhibitor of CYP3A4 in humans, but also a competitive inhibitor of CYP2C11 and 3A2 in rats, with Ki of 18.4, 98.7 and 66.3µM, respectively. Moreover, the presence of hydroxyl group at C-2 position of triterpenic acid in MA compared with oleanolic acid could magnify its competitive inhibition on human CYP3A4 activity. The relatively high Ki values of MA would have a low potential to cause the possible toxicity and drug interactions involving CYP enzymes, thus suggesting a sufficient safety for its putative use as a nutraceutical taken together with drugs.