Tiam1 mediates Rac1 activation and contraction-induced glucose uptake in skeletal muscle cells.

Contraction-stimulated glucose uptake in skeletal muscle requires Rac1, but the molecular mechanism of its activation is not fully understood. Treadmill running was applied to induce C57BL/6 mouse hind limb skeletal muscle contraction in vivo and electrical pulse stimulation contracted C2C12 myotube cultures in vitro. The protein levels or activities of AMPK or the Rac1-specific GEF, Tiam1, were manipulated by activators, inhibitors, siRNA-mediated knockdown, and adenovirus-mediated expression. Activated Rac1 was detected by a pull-down assay and immunoblotting. Glucose uptake was measured using the 2-NBD-glucose fluorescent analog. Electrical pulse stimulated contraction or treadmill exercise upregulated the expression of Tiam1 in skeletal muscle in an AMPK-dependent manner. Axin1 siRNA-mediated knockdown diminished AMPK activation and upregulation of Tiam1 protein expression by contraction. Tiam1 siRNA-mediated knockdown diminished contraction-induced Rac1 activation, GLUT4 translocation, and glucose uptake. Contraction increased Tiam1 gene expression and serine phosphorylation of Tiam1 protein via AMPK. These findings suggest Tiam1 is part of an AMPK-Tiam1-Rac1 signaling pathway that mediates contraction-stimulated glucose uptake in skeletal muscle cells and tissue.

Target identification of anti-diabetic and anti-obesity flavonoid derivative (Fla-CN).

Fla-CN is a flavonoid derivative with anti-diabetic and anti-obesity effects; however, its biological targets are still unknown. In this study, we developed bifunctional affinity-based probes to identify the direct targets of Fla-CN. When using probe 3, we observed the co-location of probe 3 and mitochondria in both HepG2 and 3T3-L1 cells. The putative target proteomes were obtained using activity-based protein profiling (ABPP) and photo-affinity labelling. Pyruvate carboxylase, mitochondrial malate dehydrogenase, mitochondrial complex I, and F1FO-ATPase were validated as the direct targets of Fla-CN by surface plasmon resonance (SPR) and biochemical assays. It was elucidated that the Tyr651, Gln870 and Lys912 were the key amino acid residues near the binding site of pyruvate carboxylase with Fla-CN. The direct interaction of Fla-CN and the above four targets allowed elucidation of its complicated molecular mechanism, including the activation of adenosine 5-monophosphate (AMP)-activated protein kinase (AMPK), and the inhibition of gluconeogenesis. Further investigation for activation of AMPK in normal and insulin resistance (IR) HepG2 cells, indicated that Fla-CN could target insulin resistance tissues.

Alkaloid Derivative (Z)-3ß-Ethylamino-Pregn-17(20)-en Inhibits Triple-Negative Breast Cancer Metastasis and Angiogenesis by Targeting HSP90α.

Metastasis is an important cause of cancer-related death. Previous studies in our laboratory found that pregnane alkaloids from Pachysandra terminalis had antimetastatic activity against breast cancer cells. In the current study, we demonstrated that treatment with one of the alkaloid derivatives, (Z)-3ß-ethylamino-pregn-17(20)-en (1), led to the downregulation of the HIF-1α/VEGF/VEGFR2 pathway, suppressed the phosphorylation of downstream molecules Akt, mTOR, FAK, and inhibited breast cancer metastasis and angiogenesis both in vitro and in vivo. Furthermore, the antimetastasis and antiangiogenesis effects of 1 treatment (40 mg/kg) were more effective than that of Sorafenib (50 mg/kg). Surface plasmon resonance (SPR) analysis was performed and the result suggested that HSP90α was a direct target of 1. Taken together, our results suggested that compound 1 might represent a candidate antitumor agent for metastatic breast cancer.

Alkaloid derivative ION-31a inhibits breast cancer metastasis and angiogenesis by targeting HSP90α.

Breast cancer has become the number one killer of women. In our previous study, an active compound, ION-31a, with potential anti-metastasis activity against breast cancer was identified through the synthesis of ionone alkaloid derivatives. In the present study, we aimed to identify the therapeutic target of ION-31a. We used a fluorescence tag labeled probe, molecular docking simulation, and surface plasmon resonance (SPR) analysis to identify the target of ION-31a. The main target of ION-31a was identified as heat shock protein 90 (HSP90). Thus, ION-31a is a novel HSP90 inhibiter that could suppress the metastasis of breast cancer and angiogenesis significantly in vitro and in vivo. ION-31a acts via inhibiting the HSP90/hypoxia inducible factor 1 alpha (HIF-1α)/vascular endothelial growth factor (VEGF)/VEGF receptor 2 (VEGFR2) pathway and downregulating downstream signal pathways, including protein kinase B (AKT)/mammalian target of rapamycin (mTOR), AKT2/protein kinase C epsilon (PKCζ), extracellular regulated kinase 1/2 (ERK1/2), focal adhesion kinase (FAK), and mitogen-activated protein kinase 14 (p38MAPK) pathways. ION-31a affects multiple effectors implicated in tumor metastasis and has the potential to be developed as an anti-metastatic agent to treat patients with breast cancer.

An AMPK/Axin1-Rac1 signaling pathway mediates contraction-regulated glucose uptake in skeletal muscle cells.

Contraction stimulates skeletal muscle glucose uptake predominantly through activation of AMP-activated protein kinase (AMPK) and Rac1. However, the molecular details of how contraction activates these signaling proteins are not clear. Recently, Axin1 has been shown to form a complex with AMPK and liver kinase B1 during glucose starvation-dependent activation of AMPK. Here, we demonstrate that electrical pulse-stimulated (EPS) contraction of C2C12 myotubes or treadmill exercise of C57BL/6 mice enhanced reciprocal coimmunoprecipitation of Axin1 and AMPK from myotube lysates or gastrocnemius muscle tissue. Interestingly, EPS or exercise upregulated total cellular Axin1 levels in an AMPK-dependent manner in C2C12 myotubes and gastrocnemius mouse muscle, respectively. Also, direct activation of AMPK with 5-aminoimidazole-4-carboxamide ribonucleotide treatment of C2C12 myotubes or gastrocnemius muscle elevated Axin1 protein levels. On the other hand, siRNA-mediated Axin1 knockdown lessened activation of AMPK in contracted myotubes. Further, AMPK inhibition with compound C or siRNA-mediated knockdown of AMPK or Axin1 blocked contraction-induced GTP loading of Rac1, p21-activated kinase phosphorylation, and contraction-stimulated glucose uptake. In summary, our results suggest that an AMPK/Axin1-Rac1 signaling pathway mediates contraction-stimulated skeletal muscle glucose uptake.

Hypoxic adipocytes induce macrophages to release inflammatory cytokines that render skeletal muscle cells insulin resistant.

Adipose tissue hypoxia occurs early in obesity and is associated with increased tissue macrophages and systemic inflammation that impacts muscle insulin responsiveness. We investigated how hypoxia interacted with adipocyte-macrophage crosstalk and inflammatory cytokine release, using co-culture and conditioned media (CM). Murine primary adipocytes from lean or obese mice were cultured under normoxic (21% O2) or hypoxic (1% O2) conditions. RAW264.7 macrophages were incubated under normoxic or hypoxic conditions with or without adipocyte conditioned media. Macrophage and adipocyte-macrophage co-culture CM were also collected. We found hypoxia did not elicit direct cytokine release from macrophages. However, adipocyte CM or adipocyte co-culture, synergistically stimulated TNFα and MCP-1 release from macrophages that was not further impacted by hypoxia. Exposure of muscle cells to elevated cytokines led to reduced insulin and muscle stress/inflammatory signaling. We conclude hypoxia or obesity induces release of inflammatory TNFα and MCP-1 from mice primary adipocytes but the two environmental conditions do not synergize to worsen macrophage signal transduction or insulin responsiveness.

Flavonoid derivatives synthesis and anti-diabetic activities.

In high fat diet-induced obese mice, the flavonoid derivative of tiliroside, Fla-CN, has antihyperglycemic effects, can improve insulin sensitivity, ameliorate metabolic lipid disorders, and benefits certain disorders characterized by insulin resistance. Fla-CN is a novel lead compound to discovery anti-diabetic and anti-obesity drugs. The present study reported the optimization of Fla-CN to obtain a new derivative, 10b, which has improved glucose consumption at the nanomolar level (EC50 = 0.3 nM) in insulin resistant (IR) HepG2 cells. 10b also increased the glycogen content and glucose uptake, and concurrently inhibited gluconeogenesis in HepG2 cells. Western blotting showed that 10b markedly enhanced the phosphorylation of AMPK (AMP-activated protein kinase) and AS160 (protein kinase B substrate of 160 kDa) and reduced the levels of the gluconeogenesis key enzymes PEPCK (phosphoenolpyruvate carboxykinase) and G6P (glucose 6-phosphatase) in HepG2 cells. The potential molecular mechanism of 10b may be activation of the AMPK/AS160 and AMPK/PEPCK/G6P pathways. We concluded that 10b might be a valuable candidate to discover anti-diabetic drugs.

Isolation and characterization of diterpene glycosides from Siegesbeckia pubescens.

Five new diterpenoid glycosides, siegesides A-E (1-5), along with the known compound darutoside (6) were isolated and characterized from the ethanol extract of Siegesbeckia pubescens. The structural elucidation of the isolates was accomplished by extensive HRESIMS and NMR analysis. Compounds 1 and 2 are epimers of 6. All isolates were evaluated for their inhibition on the migration of MB-MDA-231 breast cancer cells induced by the chemokine epithelial growth factor, and compound 2 showed superior inhibitory activities in comparison with the positive control drug with IC50 value of 0.27µM.

ent-Strobane and ent-Pimarane Diterpenoids from Siegesbeckia pubescens.

Two strobane diterpenoids, strobols A (1) and B (2), 15 new pimarane diterpenoids (3-6 and 8-18), and the known compounds kirenol (19), darutigenol (20), and ent-2ß,15,16,19-tetrahydroxypimar-8(14)-ene (7) were isolated from the aerial parts of Siegesbeckia pubescens Makino. The structures of the new compounds were established based on the interpretation of HRESIMS and NMR analysis. The configurations of 1, 6, and 17 were confirmed by X-ray crystallographic data. Compounds 3, 5, and 11 inhibited the migration of MB-MDA-231 breast cancer cells induced by the chemokine epithelial growth factor, with IC50 values of 4.26, 3.45, and 9.70 µM, respectively.

1,6-O,O-Diacetylbritannilactone suppresses activation of mast cell and airway hyper-responsiveness.

Mast cells play critical roles in allergic disorders such as atopic dermatitis and allergic asthma. The aim of this study was to investigate the anti-inflammatory and anti-asthmatic activities of 1,6-O,O-diacetylbritannilactone (OODBL) isolated from Inula japonica Thunb. (I. japonica) in a murine asthma model and bone marrow-derived mast cells (BMMCs). In an ovalbumin-induced asthma model, OODBL administration attenuated the airway hyper-responsiveness induced by aerosolized methacholine and serum IgE level in asthmatic mice. In vitro system, we found that OODBL reduced leukotriene C4 production and degranulation through the suppression of cytosolic phospholipase A2 phosphorylation and phospholipase Cγ-mediated Ca2+ influx in IgE/antigen-stimulated BMMCs. Taken together, OODBL may have therapeutic potential in the treatment of allergic diseases such as asthma.

Preparation and characterization of micro-cell membrane chromatographic column with silica-based porous layer open tubular capillary as cellular membrane carrier.

Cell membrane chromatography (CMC) is a powerful tool to study membrane protein interactions and to screen active compounds extracted from natural products. Unfortunately, a large amount of cells are typically required for column preparation in order to carry out analyses in an efficient manner. Micro-CMC (mCMC) has recently been developed by using a silica capillary as a membrane carrier. However, a reduced retention of analytes is generally associated with mCMC mostly due to a low ligand (cellular membrane) capacity. To solve this common problem, in this work a silica-based porous layer open tubular (PLOT) capillary was fabricated and, to the best of our knowledge, for the first time applied to mCMC. The mCMC column was prepared by physical adsorption of rabbit red blood cell (rRBC) membranes onto the inner surface of the PLOT capillary. The effects of the PLOT capillaries fabricated by different feed compositions, on the immobilization amount of cellular membranes (represented by the fluorescence intensity of the capillary immobilized with fluorescein isothiocyanate isomer-labeled cellular membranes) and on the dynamic binding capacity (DBC) of verapamil (VP, a widely used calcium antagonist which specific interacts with L-type calcium channel proteins located on cellular membrane of rRBC) have been systematically investigated. The fluorescence intensity of the mCMC column when combined with the PLOT capillary was found to be more than five times higher than the intensity using a bare capillary. This intriguing result indicates that the PLOT capillary exhibits a higher cellular membrane capacity. The DBC of VP in the PLOT column was found to be more than nine times higher than that in the bare capillary. An rRBC/CMC column was also prepared for comparative studies. As a result, mCMC provides similar chromatographic retention factors and stability with common CMC; however, the cellular membrane consumption for mCMC was found to be more than 460 times lower than that for CMC. Graphical Abstract Comparision of mCMC chromatograms and SEM images between bare capillary and PLOT capillary.

Cell extraction combined with off-line HPLC for screening active compounds from Coptis chinensis.

Cell membrane chromatography is a useful tool for screening active compounds from natural products. As the reason of separation mechanism, traditional cell membrane chromatography could not be used for screening the active compounds absorbed through the cell membrane and influencing the cell signal transduction pathway. In this work, we establish a new method named cell extraction combined with off-line HPLC for screening the compounds penetrating the cell membrane. This is the first time 3 T3-L1 adipocyte culture has been combined with HPLC technology. Compared with other cell membrane chromatography methods, there is good resolution and no further analysis by other chromatographic steps is required. On co-incubating crude extracts of Coptis chinensis with cells and analyzing the compounds extracted by the cells, active compounds such as berberine were detected. Glucose consumption tests showed that berberine could increase glucose consumption by insulin-resistant 3 T3-L1 adipocytes. The levels of intracellular berberine correlated with its activity. The results indicate that the developed method could be an alternative method for screening active compounds from natural products.

Two new eunicellin diterpenoids from the East China Sea gorgonian Muricella sp.

A phytochemical investigation on gorgonian Muricella sp. from East China Sea resulted in the isolation of eight eunicellin diterpenoids including two new ones, muricellins A-B (1, 2). Chemical structures of these compounds were elucidated by spectroscopic techniques (1D and 2D NMR and MS) and by comparison with data reported in the literature. Anti-rheumatoid arthritis activities of 1, 3, 4, and 6 have been evaluated.

Terminamines K-S, Antimetastatic Pregnane Alkaloids from the Whole Herb of Pachysandra terminalis.

Nine new pregnane alkaloids (1-9), together with eight known alkaloids (10-17), were isolated from the whole herb of Pachysandra terminalis. Their structures were elucidated on the basis of spectroscopic analyses. In addition, the isolates were examined for their ability to inhibit the migration of MDA-MB-231 cells induced by the chemokine epidermal growth factor (EGF). Alkaloids 1, 5, 7, 9, 12, and 17 presented significant anti-metastasis activities compared with the positive reagent, LY294002.

Functionalized Graphene Oxide with Hepatocyte Targeting as Anti-Tumor Drug and Gene Intracellular Transporters.

In order to realize the hepatocyte-specific targeted delivery of anti-tumor drug and gene, lactosylated chitosan oligosaccharide (LCO) functionalized graphene oxides (GO-LCO) containing quaternary ammonium groups (GO-LCO+) were prepared. The formation and composition of GO-LCO+ were confirmed by FTIR, AFM, TGA and zeta-potential. The in vitro cells uptakes of this functionalized GO were investigated and the results showed that GO-LCO+ can deliver fluorescein FAM-labeled DNA sequence (FAM-DNA) into human hepatic carcinoma cells (QGY-7703) with higher efficiency than positively charged chitosan oligosaccharide (CO) functionalized graphene oxides (GO-CO+) without Lactose acid modification. The loading efficiency of doxorubicin chloride (Dox) on GO-LCO+ with 477 µg/mg was obtained at the initial Dox concentration of 0.45 mg/ml and release of Dox on GO-LCO+ showed strong pH dependence. The toxicity of GO-LCO+ before and after loading with Dox toward QGY-7703 cells was further investigated. Our results suggest the functionalized GO to be used as a nanocarrier for hepatocyte targeted co-delivery of anti-tumor drugs and genes with low cytotoxicity, promising for future applications in anticancer drug and gene combined therapy.

Three new polyunsaturated lipids from a Guangxi marine sponge Haliclona sp.

Three new polyunsaturated lipids, (6Z,9Z,12Z,15Z)-octadeca-6,9,12,15-tetraen-3-one (1), (6Z,9Z,12Z,15Z)-1-bromooctadeca-6,9,12,15-tetraen-3-one (2), and (Z)-ethyl docos-5-enoate (3), together with two known polyunsaturated lipids, 4(Z),7(Z),10(Z)-tridecatrienoic acid (4) and (6Z,9Z,12Z,15Z)-octadeca-1,6,9,12,15-pentaen-3-one (5), were isolated from the marine sponge Haliclona sp., which was collected from Guangxi, using HSCCC and HPLC methods. Chemical structures of the five compounds were elucidated by spectroscopic techniques.

[Anti-tumor metastatic constituents from Rhodiola wallichiana].

To study the anti-tumor metastatic constituents in Rhodiola wallichiana (HK) S H Fu var Cholaensis (Praeg) S H Fu, chemical constituents were isolated and purified by repeated column chromatography (silica gel, Toyopearl HW-40C and preparative HPLC). Their structures were elucidated on the basis of spectral data analysis. The anti-tumor metastasis assay was applied to evaluate the activities of the isolated compounds. Ten compounds (1-10) were isolated and their structures were identified by comparison of their spectral data with literature as follows: syringic acid (1), salidroside (2), tyrosol (3), scaphopetalone (4), berchemol (5), 2,6-dimethoxyacetophenone (6), rhobupcyanoside A (7), miyaginin (8), chavicol-4-O-ß-D-apiofuranosyl-(1 --> 6)-O-ß-D-glucopyranoside (9), eugenyol-O-ß-D-apiofuranosyl-(1 --> 6)-O-ß-D-glucopyranoside (10). Compounds 4-6 and 8-10, were isolated from this genus for the first time, while compound 7 was isolated from this plant for the first time. Compounds 2, 6-8 showed positive anti-tumor metastatic activities, and compounds 2 and 8 showed significant anti-tumor metastatic activities.

[Chemical constituents from stems of Hedyotis hedyotidea and their immunosuppressive activity].

Hedyotis hedyotidea has been traditionally used for the treatment of arthritis, cold, cough, gastro-enteritis, headstroke, etc. But few studies have screened the active compounds from extracts of H. hedyotidea. In this study, the structure of the chemical constituents from stems of H. hedyotidea were determined and the immunosuppressive activity of the compounds was evaluated. The compounds were separated and purified with silica gel, gel column chromatographies and preparative HPLC, and their structures were identified by spectral methods such as MS and NMR. Eleven compounds were obtained and identified as(6S,9S) -vomifoliol (1), betulonic acid (2), betulinic acid (3), betulin(4), 3-epi-betulinic acid (5), ursolic acid (6), ß-sitosterol (7), stigmast-4-en-3-one (8), 7ß-hydroxysitosterol (9), (3ß,7ß) -7-methoxystigmast-5-en-3-ol (10) and morindacin (11). This is the first report of compounds 1, 2, 4, 8, 9, 10 and 11 from H. hedyotidea. Compounds 1, 2 and 8-11 were firstly isolated from the genus Hedyotis, and compounds 9 and 10 were isolated from the family Rubiaceae for the first time. The immunosuppressive activity of these compounds was tested using the lymphocyte transsormationtest. Compounds 4, 6 and 9 showed significant immunosuppressive activity.

Anti-inflammatory terpenes from flowers of Inula japonica.

Five new terpenes (1-5) and ten known compounds (6-15) were isolated from Inula japonica, and their structures were identified by spectroscopic analysis. Compounds 3 and 14 showed positive inhibitory effects on nitric oxide production. Furthermore, compound 14 suppressed both leukotriene C4 synthesis and degranulation in c-kit ligand-induced bone marrow-derived mast cells.

Identification of nuclear factor-κB inhibitors and ß2 adrenergic receptor agonists in Chinese medicinal preparation Fuzilizhong pills using UPLC with quadrupole time-of-flight MS.

INTRODUCTION: Fuzilizhong Pills (FZLZ), a modified form of a famous traditional Chinese medicine (TCM) Lizhong Wan in Treatise on Febrile Diseases and consisting of Panax ginseng C.A.Mey. (Ren Shen), Aconitum carmichaelii Debx. (Fu Zi, Zhi), Glycyrrhiza uralensis Fisch., Glycyrrhiza inflata Bat. or Glycyrrhiza glabra L. (Gan Cao), Atractylodes macrocephala Koidz. (Bai Zhu) and Zingiber offcinale Rosc. (Gan Jiang), show strong clinical therapeutic effects for dyspnea and pulmonary oedema. However, the bioactive compounds are still unclear. In this study, FZLZ was analysed using a rapid detection method to identify its anti-inflammatory and spasmolytic constituents. OBJECTIVE: To develop a simple screening method to detect the anti-inflammatory and spasmolytic constituents of FZLZ. METHODS: Ultra-performance liquid chromatography with quadrupole time-of-flight mass spectrometry combined with dual-bioactive (NF-κB and ß2 -adrenergic receptor) luciferase reporter assay systems was employed. RESULTS: Two ß2 -adrenergic receptor agonists (salsolinol and higeramine) and three terpenoidal analogues of NF-κB inhibitors such as ginsenosides derivatives, triperpenoids derivatives and diester-diterpenoid aconitum alkaloid derivatives were characterised. Mesaconitine, flaconitine, ginsenosides Rb2, Rf, Rg2, F1 and Ro were considered to be new NF-κB inhibitors. Furthermore, IL-8 detection by enzyme linked immunosorbent assay confirmed the anti-inflammatory effects of the potential NF-κB inhibitors. CONCLUSION: Compared with conventional fingerprints, activity-integrated fingerprints that contain both chemical and bioactive details offer a more comprehensive understanding of the chemical composition of plant materials. This strategy clearly demonstrated that dual bioactivity-integrated fingerprinting is a powerful tool for the improved screening and identification of potential dual-target lead compounds in complex herbal medicines.