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Tewari S.G.,University of Michigan | Zhou Y.,HD Biosciences | Otto B.J.,Medical College of Wisconsin | Dash R.K.,Medical College of Wisconsin | And 2 more authors.
Frontiers in Physiology | Year: 2015

The voltage-dependent anion channel (VDAC) is the main conduit for permeation of solutes (including nucleotides and metabolites) of up to 5 kDa across the mitochondrial outer membrane (MOM). Recent studies suggest that VDAC activity is regulated via post-translational modifications (PTMs). Yet the nature and effect of these modifications is not understood. Herein, single channel currents of wild-type, nitrosated, and phosphorylated VDAC are analyzed using a generalized continuous-time Markov chain Monte Carlo (MCMC) method. This developed method describes three distinct conducting states (open, half-open, and closed) of VDAC activity. Lipid bilayer experiments are also performed to record single VDAC activity under un-phosphorylated and phosphorylated conditions, and are analyzed using the developed stochastic search method. Experimental data show significant alteration in VDAC gating kinetics and conductance as a result of PTMs. The effect of PTMs on VDAC kinetics is captured in the parameters associated with the identified Markov model. Stationary distributions of the Markov model suggest that nitrosation of VDAC not only decreased its conductance but also significantly locked VDAC in a closed state. On the other hand, stationary distributions of the model associated with un-phosphorylated and phosphorylated VDAC suggest a reversal in channel conformation from relatively closed state to an open state. Model analyses of the nitrosated data suggest that faster reaction of nitric oxide with Cys-127 thiol group might be responsible for the biphasic effect of nitric oxide on basal VDAC conductance. © 2015 Tewari, Zhou, Otto, Dash, Kwok and Beard.


PubMed | CAS Beijing Institute of Genomics, Beijing University of Chinese Medicine, HD Biosciences and ACEA Inc
Type: Journal Article | Journal: International journal of molecular sciences | Year: 2016

Endothelin-1 (ET-1) autocrine and paracrine signaling modulate cell proliferation of tumor cells by activating its receptors, endothelin A receptor (ETAR) and endothelin B receptor (ETBR). Dysregulation of ETAR activation promotes tumor development and progression. The potential of ETAR antagonists and the dual-ETAR and ETBR antagonists as therapeutic approaches are under preclinical and clinical studies. Salvianolic acid A (Sal A) is a hydrophilic polyphenolic derivative isolated from Salvia miltiorrhiza Bunge (Danshen), which has been reported as an anti-cancer and cardio-protective herbal medicine. In this study, we demonstrate that Sal A inhibits ETAR activation induced by ET-1 in both recombinant and endogenous ETAR expression cell lines. The IC50 values were determined as 5.7 M in the HEK293/ETAR cell line and 3.14 M in HeLa cells, respectively. Furthermore, our results showed that Sal A suppressed cell proliferation and extended the doubling times of multiple cancer cells, including HeLa, DU145, H1975, and A549 cell lines. In addition, Sal A inhibited proliferation of DU145 cell lines stimulated by exogenous ET-1 treatment. Moreover, the cytotoxicity and cardio-toxicity of Sal A were assessed in human umbilical vein endothelial cells (HUVEC) and Human-induced pluripotent stem cell-derived cardiomyocytes (hiPS-CMs), which proved that Sal A demonstrates no cytotoxicity or cardiotoxicity. Collectively, our findings indicate that Sal A is a novel anti-cancer candidate through targeting ETAR.


Pietra C.,Helsinn Healthcare SA | Takeda Y.,ONO Pharmaceutical Co. | Tazawa-Ogata N.,ONO Pharmaceutical Co. | Minami M.,ONO Pharmaceutical Co. | And 3 more authors.
Journal of Cachexia, Sarcopenia and Muscle | Year: 2014

Background: Anamorelin HCl (ANAM) is a novel, orally active, ghrelin receptor agonist in clinical development for the treatment of cancer cachexia. We report in vitro and in vivo studies evaluating the preclinical pharmacologic profile of ANAM.Results: ANAM showed significant agonist and binding activity on the ghrelin receptor, and stimulated GH release in vitro. In rats, ANAM significantly and dose-dependently increased FI and BW at all dose levels compared with control, and significantly increased GH levels at 10 or 30 mg/kg doses. Increases in GH and IGF-1 levels were observed following ANAM administration in pigs.Conclusion: ANAM is a potent and highly specific ghrelin receptor agonist with significant appetite-enhancing activity, leading to increases in FI and BW, and a stimulatory effect on GH secretion. These results support the continued investigation of ANAM as a potential treatment of cancer anorexia-cachexia syndrome.Methods: Fluorescent imaging plate reader and binding assays in HEK293 and baby hamster kidney cells determined the agonist and antagonist activity of ANAM, and its affinity for the ghrelin receptor. Rat pituitary cells were incubated with ANAM to evaluate its effect on growth hormone (GH) release. In vivo, rats were treated with ANAM 3, 10, or 30 mg/kg, or control orally, once daily for 6 days to evaluate the effect on food intake (FI) and body weight (BW), and once to assess GH response. In pigs, single (3.5 mg/kg) or continuous (1 mg/kg/day) ANAM doses were administered to assess GH and insulin-like growth factor (IGF-1) response. © 2014, Springer-Verlag Berlin Heidelberg.


Chuykin I.,Max Delbrück Center for Molecular Medicine | Lapidus I.,Max Delbrück Center for Molecular Medicine | Popova E.,Max Delbrück Center for Molecular Medicine | Vilianovich L.,Max Delbrück Center for Molecular Medicine | And 6 more authors.
PLoS ONE | Year: 2010

Background: Previous attempts to isolate pluripotent cell lines from rat preimplantation embryo in mouse embryonic stem (ES) cell culture conditions (serum and LIF) were unsuccessful, however the resulting cells exhibited the expression of such traditional pluripotency markers as SSEA-1 and alkaline phosphatase. We addressed the question, which kind of cell lineages are produced from rat preimplantation embryo under "classical" mouse ES conditions. Results: We characterized two cell lines (C5 and B10) which were obtained from rat blastocysts in medium with serum and LIF. In the B10 cell line we found the expression of genes known to be expressed in trophoblast, Cdx-2, cytokeratin-7, and Hand-1. Also, B10 cells invaded the trophectodermal layer upon injection into rat blastocysts. In contrast to mouse Trophoblast Stem (TS) cells proliferation of B10 cells occurred independently of FGF4. Cells of the C5 line expressed traditional markers of extraembryonic-endoderm (XEN) cells, in particular, GATA-4, but also the pluripotency markers SSEA-1 and Oct-4. C5 cell proliferation exhibited dependence on LIF, which is not known to be required by mouse XEN cells. Conclusions: Our results confirm and extend previous findings about differences between blastocyst-derived cell lines of rat and mice. Our data show, that the B10 cell line represents a population of FGF4-independent rat TS-like cells. C5 cells show features that have recently become known as characteristic of rat XEN cells. Early passages of C5 and B10 cells contained both, TS and XEN cells. We speculate, that mechanisms maintaining self-renewal of cell lineages in rat preimplantation embryo and their in vitro counterparts, including ES, TS and XEN cells are different than in respective mouse lineages. © 2010 Chuykin et al.


Cunnington R.H.,University of Manitoba | Wang B.,HD Biosciences | Ghavami S.,University of Manitoba | Bathe K.L.,University of Manitoba | And 2 more authors.
American Journal of Physiology - Cell Physiology | Year: 2011

Cardiac myofibroblasts are key players in chronic remodeling of the cardiac extracellular matrix, which is mediated in part by elevated transforming growth factor-β1 (TGF-β1). The c-Ski proto-oncoprotein has been shown to modify TGF-β1 post-receptor signaling through receptor-activated Smads (R-Smads); however, little is known about how c-Ski regulates fibroblast phenotype and function. We sought to elucidate the function of c-Ski in primary cardiac myofibroblasts using a c-Ski overexpression system. Cardiac myofibroblasts expressed three forms of c-Ski with the predominant band at 105 kDa, and adenoviral c-Ski treatment resulted in overexpression of 95-kDa c-Ski in cellular nuclei. Exogenous c-Ski led to significant inhibition of type I collagen secretion and myofibroblast contractility using two-dimensional semifloating gel contraction assay in both basal and with TGF-β1 (10 ng/ml for 24 h) stimulation. Overexpressed c-Ski did not inhibit nuclear translocation of phosphorylated R-Smad2, despite their binding, as demonstrated by immunoprecipitation. Acute treatment of primary myofi-broblasts with TGF-β1 in vitro revealed a marked nuclear shuttling of c-Ski at 24 and 48 h following stimulation. Remarkably, overexpression of c-Ski led to a stepwise reduction of the myofibroblast marker α-smooth muscle actin with increasing multiplicity of infection, and these results indicate that 95-kDa c-Ski overexpression may effect a loss of the myofibroblastic phenotype. Furthermore, adenovirus (Ad) for hemagglutinin-tagged c-Ski infection led to a reduction in the number of myofibroblasts versus Ad-LacZ-infected and uninfected controls, due to induction of apoptosis. Finally, we observed a significant increase in 105-kDa c-Ski in the cytosolic fraction of cells of the infarct scar and adjacent remnant myocardium vs. noninfarcted controls. Copyright © 2011 the American Physiological Society.


PubMed | CAS Beijing Institute of Genomics, Beijing University of Chinese Medicine and HD Biosciences
Type: Journal Article | Journal: Biochemical and biophysical research communications | Year: 2016

Studies of human genetics have implicated the role of SIRT1 in regulating obesity, insulin resistance, and longevity. These researches motivated the identification of novel SIRT1 activators. The current study aimed to investigate the potential efficacy of agrimol B, a polyphenol derived from Agrimonia pilosa Ledeb., on mediating SIRT1 activity and fat metabolism. Results showed that agrimol B significantly induced cytoplasm-to-nucleus shuttle of SIRT1. Furthermore, we confirmed that agrimol B dramatically inhibited 3T3-L1 adipocyte differentiation by reducing PPAR, C/EBP, FAS, UCP-1, and apoE expression. Consequently, adipogenesis was blocked by treatment of agrimol B at the early stage of differentiation in a dose-dependent manner, the IC50 value was determined as 3.350.32M. Taken together, our data suggest a therapeutic potential of agrimol B on alleviating obesity, through modulation of SIRT1-PPAR signal pathway.


PubMed | CAS Beijing Institute of Genomics, Beijing University of Chinese Medicine and HD Biosciences
Type: Journal Article | Journal: Molecules (Basel, Switzerland) | Year: 2016

The increasing demand for safe and effective treatments of chronic pain has promoted the investigation of novel analgesic drugs. Some herbals have been known to be able to relieve pain, while the chemical basis and target involved in this process remained to be clarified. The current study aimed to find anti-nociceptive candidates targeting transient receptor potential ankyrin 1 (TRPA1), a receptor that implicates in hyperalgesia and neurogenic inflammation. In the current study, 156 chemicals were tested for blocking HEK293/TRPA1 ion channel by calcium-influx assay. Docking study was conducted to predict the binding modes of hit compound with TRPA1 using Discovery Studio. Cytotoxicity in HEK293 was conducted by Cell Titer-Glo assay. Additionally, cardiotoxicity was assessed via xCELLigence RTCA system. We uncovered that cardamonin selectively blocked TRPA1 activation while did not interact with TRPV1 nor TRPV4 channel. A concentration-dependent inhibitory effect was observed with IC50 of 454 nM. Docking analysis of cardamonin demonstrated a compatible interaction with A-967079-binding site of TRPA1. Meanwhile, cardamonin did not significantly reduce HEK293 cell viability, nor did it impair cardiomyocyte constriction. Our data suggest that cardamonin is a selective TRPA1 antagonist, providing novel insight into the target of its anti-nociceptive activity.


Kazmierski W.M.,Glaxosmithkline | Maynard A.,Glaxosmithkline | Duan M.,HD Biosciences | Baskaran S.,Glaxosmithkline | And 9 more authors.
Journal of Medicinal Chemistry | Year: 2014

Rapid clinical progress of hepatitis C virus (HCV) replication inhibitors, including these selecting for resistance in the NS5A region (NS5A inhibitors), promises to revolutionize HCV treatment. Herein, we describe our explorations of diverse spiropyrrolidine motifs in novel NS5A inhibitors and a proposed interaction model. We discovered that the 1,4-dioxa-7-azaspiro[4.4]nonane motif in inhibitor 41H (GSK2236805) supported high potency against genotypes 1a and 1b as well as in genotype 1b L31V and Y93H mutants. Consistent with this, 41H potently suppressed HCV RNA in the 20-day RNA reduction assay. Pharmacokinetic and safety data supported further progression of 41H to the clinic. © 2014 American Chemical Society.


Wang S.,Shanghai University of Traditional Chinese Medicine | Lin X.,Shanghai University of Traditional Chinese Medicine | Wang L.-Y.,Shanghai University of Traditional Chinese Medicine | Ruan K.-F.,Shanghai University of Traditional Chinese Medicine | And 2 more authors.
International Journal of Biological Macromolecules | Year: 2012

Ophiopogon japonicus is a traditional Chinese medicine used to treat cardiovascular disease. Recent studies have confirmed the anti-ischemic properties of a water-soluble β-d-fructan (MDG-1) from O. japonicus. The sphingosine 1-phosphate (S1P) signaling pathway is involved in its cytoprotective effects. Herein, we explore the role of the S1P signaling pathway in the anti-ischemic effect of MDG-1 and assess one possible mechanism by which it induces S1P release and sphingosine 1-phosphate receptor 1 (S1P 1) expression in human microvascular endothelial cells (HMEC-1) and cardiomyocytes. Our evidence demonstrates that MDG-1 promotes sphingosine kinase (SPHK) activity in HMEC-1 cells. An analytical method for measuring the mass of S1P using ESI/MS/MS was developed and we found that MDG-1 increases intracellular S1P levels. Meanwhile, MDG-1 is protective during hypoxia and ischemia through mechanisms that require S1P 1 receptor activation, which was confirmed both in oxygen glucose deprivation (OGD) and coronary artery ligation models by using transfection of cloned human S1P 1 receptor and RNA interference. These data indicate that the increase of intracellular S1P generation, particularly by activation of the SPHK enzyme, coupled with the autocrine and paracrine stimulation of cell surface S1P receptors, is a potential mechanism in the anti-ischemic and cell protective effect of MDG-1. © 2011 Elsevier B.V.


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