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Sample records for acid significantly inhibited

  1. Boric acid and boronic acids inhibition of pigeonpea urease.

    PubMed

    Reddy, K Ravi Charan; Kayastha, Arvind M

    2006-08-01

    Urease from the seeds of pigeonpea was competitively inhibited by boric acid, butylboronic acid, phenylboronic acid, and 4-bromophenylboronic acid; 4-bromophenylboronic acid being the strongest inhibitor, followed by boric acid > butylboronic acid > phenylboronic acid, respectively. Urease inhibition by boric acid is maximal at acidic pH (5.0) and minimal at alkaline pH (10.0), i.e., the trigonal planar B(OH)3 form is a more effective inhibitor than the tetrahedral B(OH)4 -anionic form. Similarly, the anionic form of phenylboronic acid was least inhibiting in nature.

  2. Novel Bioactivity of Ellagic Acid in Inhibiting Human Platelet Activation

    PubMed Central

    Chang, Yi; Chen, Wei-Fan; Lin, Kuan-Hung; Hsieh, Cheng-Ying; Chou, Duen-Suey; Lin, Li-Jyun; Sheu, Joen-Rong; Chang, Chao-Chien

    2013-01-01

    Pomegranates are widely consumed either as fresh fruit or in beverage form as juice and wine. Ellagic acid possesses potent antioxidative properties; it is known to be an effective phytotherapeutic agent with antimutagenic and anticarcinogenic qualities. Ellagic acid (20 to 80 μM) exhibited a potent activity in inhibiting platelet aggregation stimulated by collagen; however, it did not inhibit platelet aggregation stimulated by thrombin, arachidonic acid, or U46619. Treatment with ellagic acid (50 and 80 μM) significantly inhibited platelet activation stimulated by collagen; this alteration was accompanied by the inhibition of relative [Ca2+]i mobilization, and the phosphorylation of phospholipase C (PLC)γ2, protein kinase C (PKC), mitogen-activated protein kinases (MAPKs), and Akt, as well as hydroxyl radical (OH●) formation. In addition, ellagic acid also inhibited p38 MAPK and Akt phosphorylation stimulated by hydrogen peroxide. By contrast, ellagic acid did not significantly affect PKC activation and platelet aggregation stimulated by PDBu. This study is the first to show that, in addition to being considered a possible agent for preventing tumor growth, ellagic acid possesses potent antiplatelet properties. It appears to initially inhibit the PLCγ2-PKC cascade and/or hydroxyl radical formation, followed by decreased phosphorylation of MAPKs and Akt, ultimately inhibiting platelet aggregation. PMID:23533502

  3. Nickel inhibits mitochondrial fatty acid oxidation.

    PubMed

    Uppala, Radha; McKinney, Richard W; Brant, Kelly A; Fabisiak, James P; Goetzman, Eric S

    2015-08-01

    Nickel exposure is associated with changes in cellular energy metabolism which may contribute to its carcinogenic properties. Here, we demonstrate that nickel strongly represses mitochondrial fatty acid oxidation-the pathway by which fatty acids are catabolized for energy-in both primary human lung fibroblasts and mouse embryonic fibroblasts. At the concentrations used, nickel suppresses fatty acid oxidation without globally suppressing mitochondrial function as evidenced by increased glucose oxidation to CO2. Pre-treatment with l-carnitine, previously shown to prevent nickel-induced mitochondrial dysfunction in neuroblastoma cells, did not prevent the inhibition of fatty acid oxidation. The effect of nickel on fatty acid oxidation occurred only with prolonged exposure (>5 h), suggesting that direct inhibition of the active sites of metabolic enzymes is not the mechanism of action. Nickel is a known hypoxia-mimetic that activates hypoxia inducible factor-1α (HIF1α). Nickel-induced inhibition of fatty acid oxidation was blunted in HIF1α knockout fibroblasts, implicating HIF1α as one contributor to the mechanism. Additionally, nickel down-regulated the protein levels of the key fatty acid oxidation enzyme very long-chain acyl-CoA dehydrogenase (VLCAD) in a dose-dependent fashion. In conclusion, inhibition of fatty acid oxidation by nickel, concurrent with increased glucose metabolism, represents a form of metabolic reprogramming that may contribute to nickel-induced carcinogenesis.

  4. Nickel Inhibits Mitochondrial Fatty Acid Oxidation

    PubMed Central

    Uppala, Radha; McKinney, Richard W.; Brant, Kelly A.; Fabisiak, James P.; Goetzman, Eric S.

    2015-01-01

    Nickel exposure is associated with changes in cellular energy metabolism which may contribute to its carcinogenic properties. Here, we demonstrate that nickel strongly represses mitochondrial fatty acid oxidation—the pathway by which fatty acids are catabolized for energy—in both primary human lung fibroblasts and mouse embryonic fibroblasts. At the concentrations used, nickel suppresses fatty acid oxidation without globally suppressing mitochondrial function as evidenced by increased glucose oxidation to CO2. Pre-treatment with L-carnitine, previously shown to prevent nickel-induced mitochondrial dysfunction in neuroblastoma cells, did not prevent the inhibition of fatty acid oxidation. The effect of nickel on fatty acid oxidation occurred only with prolonged exposure (>5 hr), suggesting that direct inhibition of the active sites of metabolic enzymes is not the mechanism of action. Nickel is a known hypoxia-mimetic that activates hypoxia inducible factor-1α (HIF1α). Nickel-induced inhibition of fatty acid oxidation was blunted in HIF1α knockout fibroblasts, implicating HIF1α as one contributor to the mechanism. Additionally, nickel down-regulated the protein levels of the key fatty acid oxidation enzyme very long-chain acyl-CoA dehydrogenase (VLCAD) in a dose-dependent fashion. In conclusion, inhibition of fatty acid oxidation by nickel, concurrent with increased glucose metabolism, represents a form of metabolic reprogramming that may contribute to nickel-induced carcinogenesis. PMID:26051273

  5. Crocetinic acid inhibits hedgehog signaling to inhibit pancreatic cancer stem cells

    PubMed Central

    Rangarajan, Parthasarathy; Subramaniam, Dharmalingam; Paul, Santanu; Kwatra, Deep; Palaniyandi, Kanagaraj; Islam, Shamima; Harihar, Sitaram; Ramalingam, Satish; Gutheil, William; Putty, Sandeep; Pradhan, Rohan; Padhye, Subhash; Welch, Danny R.; Anant, Shrikant; Dhar, Animesh

    2015-01-01

    Pancreatic cancer is the fourth leading cause of cancer deaths in the US and no significant treatment is currently available. Here, we describe the effect of crocetinic acid, which we purified from commercial saffron compound crocetin using high performance liquid chromatography. Crocetinic acid inhibits proliferation of pancreatic cancer cell lines in a dose- and time-dependent manner. In addition, it induced apoptosis. Moreover, the compound significantly inhibited epidermal growth factor receptor and Akt phosphorylation. Furthermore, crocetinic acid decreased the number and size of the pancospheres in a dose-dependent manner, and suppressed the expression of the marker protein DCLK-1 (Doublecortin Calcium/Calmodulin-Dependent Kinase-1) suggesting that crocetinic acid targets cancer stem cells (CSC). To understand the mechanism of CSC inhibition, the signaling pathways affected by purified crocetinic acid were dissected. Sonic hedgehog (Shh) upon binding to its cognate receptor patched, allows smoothened to accumulate and activate Gli transcription factor. Crocetinic acid inhibited the expression of both Shh and smoothened. Finally, these data were confirmed in vivo where the compound at a dose of 0.5 mg/Kg bw suppressed growth of tumor xenografts. Collectively, these data suggest that purified crocetinic acid inhibits pancreatic CSC, thereby inhibiting pancreatic tumorigenesis. PMID:26317547

  6. R-lipoic acid inhibits mammalian pyruvate dehydrogenase kinase.

    PubMed

    Korotchkina, Lioubov G; Sidhu, Sukhdeep; Patel, Mulchand S

    2004-10-01

    The four pyruvate dehydrogenase kinase (PDK) and two pyruvate dehydrogenase phosphatase (PDP) isoenzymes that are present in mammalian tissues regulate activity of the pyruvate dehydrogenase complex (PDC) by phosphorylation/dephosphorylation of its pyruvate dehydrogenase (E1) component. The effect of lipoic acids on the activity of PDKs and PDPs was investigated in purified proteins system. R-lipoic acid, S-lipoic acid and R-dihydrolipoic acid did not significantly affect activities of PDPs and at the same time inhibited PDKs to different extents (PDK1>PDK4 approximately PDK2>PDK3 for R-LA). Since lipoic acids inhibited PDKs activity both when reconstituted in PDC and in the presence of E1 alone, dissociation of PDK from the lipoyl domains of dihydrolipoamide acetyltransferase in the presence of lipoic acids is not a likely explanation for inhibition. The activity of PDK1 towards phosphorylation sites 1, 2 and 3 of E1 was decreased to the same extent in the presence of R-lipoic acid, thus excluding protection of the E1 active site by lipoic acid from phosphorylation. R-lipoic acid inhibited autophosphorylation of PDK2 indicating that it exerted its effect on PDKs directly. Inhibition of PDK1 by R-lipoic acid was not altered by ADP but was decreased in the presence of pyruvate which itself inhibits PDKs. An inhibitory effect of lipoic acid on PDKs would result in less phosphorylation of E1 and hence increased PDC activity. This finding provides a possible mechanism for a glucose (and lactate) lowering effect of R-lipoic acid in diabetic subjects. PMID:15512796

  7. Understanding biocatalyst inhibition by carboxylic acids

    PubMed Central

    Jarboe, Laura R.; Royce, Liam A.; Liu, Ping

    2013-01-01

    Carboxylic acids are an attractive biorenewable chemical in terms of their flexibility and usage as precursors for a variety of industrial chemicals. It has been demonstrated that such carboxylic acids can be fermentatively produced using engineered microbes, such as Escherichia coli and Saccharomyces cerevisiae. However, like many other attractive biorenewable fuels and chemicals, carboxylic acids become inhibitory to these microbes at concentrations below the desired yield and titer. In fact, their potency as microbial inhibitors is highlighted by the fact that many of these carboxylic acids are routinely used as food preservatives. This review highlights the current knowledge regarding the impact that saturated, straight-chain carboxylic acids, such as hexanoic, octanoic, decanoic, and lauric acids can have on E. coli and S. cerevisiae, with the goal of identifying metabolic engineering strategies to increase robustness. Key effects of these carboxylic acids include damage to the cell membrane and a decrease of the microbial internal pH. Certain changes in cell membrane properties, such as composition, fluidity, integrity, and hydrophobicity, and intracellular pH are often associated with increased tolerance. The availability of appropriate exporters, such as Pdr12, can also increase tolerance. The effect on metabolic processes, such as maintaining appropriate respiratory function, regulation of Lrp activity and inhibition of production of key metabolites such as methionine, are also considered. Understanding the mechanisms of biocatalyst inhibition by these desirable products can aid in the engineering of robust strains with improved industrial performance. PMID:24027566

  8. Glycation inhibits trichloroacetic acid (TCA)-induced whey protein precipitation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Four different WPI saccharide conjugates were successfully prepared to test whether glycation could inhibit WPI precipitation induced by trichloroacetic acid (TCA). Conjugates molecular weights after glycation were analyzed with SDS-PAGE. No significant secondary structure change due to glycation wa...

  9. [Significance of hydrocyanic acid formation during fires].

    PubMed

    von Meyer, L; Drasch, G; Kauert, G

    1979-01-01

    Cyanide concentrations of blood samples from fire victims autopsied in the Institute of Legal Medicine, Munich, have been determined. In 25% of 48 analyzed cases cyanide concentrations from 0.52 microgram to 6.24 microgram Cyanide/ml blood have been detected. These results are compared to former studies and the higher mean level in our collective is emphasized. The importance of hydrocyanid acid in the toxicity of fire gases is evidently greater, than assumed. Hydrocyanic acid may be produced from nitrogen continaing polymers during combustion. The quote of these polymers in clothing, furniture, and also in equipment of cars is increasing. Therefore, it is necessary to take more notice of the formation of hydrocyanic acid during combustion, even though carbon monoxide is in general the main toxic agent in fire gases.

  10. Inhibition of class IIb histone deacetylase significantly improves cloning efficiency in mice.

    PubMed

    Ono, Tetsuo; Li, Chong; Mizutani, Eiji; Terashita, Yukari; Yamagata, Kazuo; Wakayama, Teruhiko

    2010-12-01

    Since the first mouse clone was produced by somatic cell nuclear transfer, the success rate of cloning in mice has been extremely low. Some histone deacetylase inhibitors, such as trichostatin A and scriptaid, have improved the full-term development of mouse clones significantly, but the mechanisms allowing for this are unclear. Here, we found that two other specific inhibitors, suberoylanilide hydroxamic acid and oxamflatin, could also reduce the rate of apoptosis in blastocysts, improve the full-term development of cloned mice, and increase establishment of nuclear transfer-generated embryonic stem cell lines significantly without leading to obvious abnormalities. However, another inhibitor, valproic acid, could not improve cloning efficiency. Suberoylanilide hydroxamic acid, oxamflatin, trichostatin A, and scriptaid are inhibitors for classes I and IIa/b histone deacetylase, whereas valproic acid is an inhibitor for classes I and IIa, suggesting that inhibiting class IIb histone deacetylase is an important step for reprogramming mouse cloning efficiency.

  11. Inhibition studies of soybean (Glycine max) urease with heavy metals, sodium salts of mineral acids, boric acid, and boronic acids.

    PubMed

    Kumar, Sandeep; Kayastha, Arvind M

    2010-10-01

    Various inhibitors were tested for their inhibitory effects on soybean urease. The K(i) values for boric acid, 4-bromophenylboronic acid, butylboronic acid, and phenylboronic acid were 0.20 +/- 0.05 mM, 0.22 +/- 0.04 mM, 1.50 +/- 0.10 mM, and 2.00 +/- 0.11 mM, respectively. The inhibition was competitive type with boric acid and boronic acids. Heavy metal ions including Ag(+), Hg(2+), and Cu(2+) showed strong inhibition on soybean urease, with the silver ion being a potent inhibitor (IC(50) = 2.3 x 10(-8) mM). Time-dependent inhibition studies exhibited biphasic kinetics with all heavy metal ions. Furthermore, inhibition studies with sodium salts of mineral acids (NaF, NaCl, NaNO(3), and Na(2)SO(4)) showed that only F(-) inhibited soybean urease significantly (IC(50) = 2.9 mM). Competitive type of inhibition was observed for this anion with a K(i) value of 1.30 mM.

  12. Inhibition of fucosyltransferase VII by gallic acid and its derivatives.

    PubMed

    Niu, Xiaoda; Fan, Xuedong; Sun, Jing; Ting, Pauline; Narula, Satwant; Lundell, Daniel

    2004-05-01

    Gallic acid (GA) and several gallate derivatives were identified as inhibitors of fucosyltransferase VII (FucT VII). The inhibition by GA and (-)-epigallocatechin gallate (EGCG) is time-dependent and irreversible. GA and EGCG showed inhibition with IC(50) of 60 and 700 nM, respectively, after pre-incubation with FucT VII in the presence of MnCl(2). Absence of MnCl(2) results in significantly weaker inhibition. Complexation of Mn(2+) with GA, EGCG, and gallate esters was observed. Such complexation, however, is not rate-limiting for the inhibition of FucT VII. Therefore, time-dependent inhibition of fucosyltransferases by GA and EGCG is likely due to the slow inactivation by the inhibitors or Mn-inhibitor complex. Although Mg(2+) or Ca(2+) can replace Mn(2+) for FucT VII activation, none forms a complex with GA or EGCG and hence results in weaker inhibition of FucT VII. GA and EGCG also inhibit FucT IV and alpha2,3-(N)-sialyltransferase in the low micromolar range. The structure-function divergence could be observed, as EGCG, but not GA or gallate esters, inhibits Zn(2+) containing metalloproteases such as TNFalpha convertase, matrix metalloproteases 2 and 7.

  13. Chlorogenic Acid Inhibits Human Platelet Activation and Thrombus Formation

    PubMed Central

    Fuentes, Eduardo; Caballero, Julio; Alarcón, Marcelo; Rojas, Armando; Palomo, Iván

    2014-01-01

    Background Chlorogenic acid is a potent phenolic antioxidant. However, its effect on platelet aggregation, a critical factor in arterial thrombosis, remains unclear. Consequently, chlorogenic acid-action mechanisms in preventing platelet activation and thrombus formation were examined. Methods and Results Chlorogenic acid in a dose-dependent manner (0.1 to 1 mmol/L) inhibited platelet secretion and aggregation induced by ADP, collagen, arachidonic acid and TRAP-6, and diminished platelet firm adhesion/aggregation and platelet-leukocyte interactions under flow conditions. At these concentrations chlorogenic acid significantly decreased platelet inflammatory mediators (sP-selectin, sCD40L, CCL5 and IL-1β) and increased intraplatelet cAMP levels/PKA activation. Interestingly, SQ22536 (an adenylate cyclase inhibitor) and ZM241385 (a potent A2A receptor antagonist) attenuated the antiplatelet effect of chlorogenic acid. Chlorogenic acid is compatible to the active site of the adenosine A2A receptor as revealed through molecular modeling. In addition, chlorogenic acid had a significantly lower effect on mouse bleeding time when compared to the same dose of aspirin. Conclusions Antiplatelet and antithrombotic effects of chlorogenic acid are associated with the A2A receptor/adenylate cyclase/cAMP/PKA signaling pathway. PMID:24598787

  14. Inhibition of Influenza Virus Ribonucleic Acid Polymerase by Ribavirin Triphosphate

    PubMed Central

    Eriksson, Bertil; Helgstrand, Erik; Johansson, Nils Gunnar; Larsson, Alf; Misiorny, Alfons; Noren, Jan Olof; Philipson, Lennart; Stenberg, Kjell; Stening, Goran; Stridh, Stig; Öberg, Bo

    1977-01-01

    Ribavirin 5′-triphosphate (RTP), derived from the broad-spectrum antiviral compound ribavirin (Virazole), can selectively inhibit influenza virus ribonucleic acid polymerase in a cell-free assay. Ribavirin and its 5′-monophosphate have no effect on the polymerase. The inhibition is competitive with respect to adenosine 5′-triphosphate and guanosine 5′-triphosphate. RTP also inhibits ApG- and GpC-stimulated influenza virus ribonucleic acid polymerase. Since ribavirin is phosphorylated in the cell, the inhibition of influenza multiplication in the cell may also be caused by RTP. PMID:879760

  15. Boric acid inhibits embryonic histone deacetylases: A suggested mechanism to explain boric acid-related teratogenicity

    SciTech Connect

    Di Renzo, Francesca; Cappelletti, Graziella; Broccia, Maria L.; Giavini, Erminio; Menegola, Elena . E-mail: elena.menegola@unimi.it

    2007-04-15

    Histone deacetylases (HDAC) control gene expression by changing histonic as well as non histonic protein conformation. HDAC inhibitors (HDACi) are considered to be among the most promising drugs for epigenetic treatment for cancer. Recently a strict relationship between histone hyperacetylation in specific tissues of mouse embryos exposed to two HDACi (valproic acid and trichostatin A) and specific axial skeleton malformations has been demonstrated. The aim of this study is to verify if boric acid (BA), that induces in rodents malformations similar to those valproic acid and trichostatin A-related, acts through similar mechanisms: HDAC inhibition and histone hyperacetylation. Pregnant mice were treated intraperitoneally with a teratogenic dose of BA (1000 mg/kg, day 8 of gestation). Western blot analysis and immunostaining were performed with anti hyperacetylated histone 4 (H4) antibody on embryos explanted 1, 3 or 4 h after treatment and revealed H4 hyperacetylation at the level of somites. HDAC enzyme assay was performed on embryonic nuclear extracts. A significant HDAC inhibition activity (compatible with a mixed type partial inhibition mechanism) was evident with BA. Kinetic analyses indicate that BA modifies substrate affinity by a factor {alpha} = 0.51 and maximum velocity by a factor {beta} = 0.70. This work provides the first evidence for HDAC inhibition by BA and suggests such a molecular mechanism for the induction of BA-related malformations.

  16. Ursolic acid and oleanolic acid from Eriobotrya fragrans inhibited the viability of A549 cells.

    PubMed

    Yuan, Yuan; Gao, Yongshun; Song, Gang; Lin, Shunquan

    2015-02-01

    Loquat {Eriobotrya japonica (Lindl.)}, a kind of Chinese herb, has many efficacies such as anti-inflammatory, antimicrobial and curing chronic bronchitis. However, reports on the pharmacological action of wild loquat extract are limited. In this work, the A549 cell line was selected to study the inhibitory effect of ursolic acid and oleanolic acid (UA, OA) from the leaves of E. fragrans. Results showed that UA/OA inhibited A549 cell viability and induced apoptosis in a dose and time dependent manner. The cell fraction in the G0/G1 phase dramatically increased under treatment with UA/OA. Data showed that UA activated the expression of PARP. UA and OA down-regulated MMP-2 and Bcl-2; on the contrary, they up-regulated Bid. This work demonstrated that UA/OA extracted from wild loquat leaves can significantly inhibit the viability of A549 cells.

  17. Amino acids inhibit kynurenic acid formation via suppression of kynurenine uptake or kynurenic acid synthesis in rat brain in vitro.

    PubMed

    Sekine, Airi; Okamoto, Misaki; Kanatani, Yuka; Sano, Mitsue; Shibata, Katsumi; Fukuwatari, Tsutomu

    2015-01-01

    The tryptophan metabolite, kynurenic acid (KYNA), is a preferential antagonist of the α7 nicotinic acetylcholine receptor at endogenous brain concentrations. Recent studies have suggested that increase of brain KYNA levels is involved in psychiatric disorders such as schizophrenia and depression. KYNA-producing enzymes have broad substrate specificity for amino acids, and brain uptake of kynurenine (KYN), the immediate precursor of KYNA, is via large neutral amino acid transporters (LAT). In the present study, to find out amino acids with the potential to suppress KYNA production, we comprehensively investigated the effects of proteinogenic amino acids on KYNA formation and KYN uptake in rat brain in vitro. Cortical slices of rat brain were incubated for 2 h in Krebs-Ringer buffer containing a physiological concentration of KYN with individual amino acids. Ten out of 19 amino acids (specifically, leucine, isoleucine, phenylalanine, methionine, tyrosine, alanine, cysteine, glutamine, glutamate, and aspartate) significantly reduced KYNA formation at 1 mmol/L. These amino acids showed inhibitory effects in a dose-dependent manner, and partially inhibited KYNA production at physiological concentrations. Leucine, isoleucine, methionine, phenylalanine, and tyrosine, all LAT substrates, also reduced tissue KYN concentrations in a dose-dependent manner, with their inhibitory rates for KYN uptake significantly correlated with KYNA formation. These results suggest that five LAT substrates inhibit KYNA formation via blockade of KYN transport, while the other amino acids act via blockade of the KYNA synthesis reaction in brain. Amino acids can be a good tool to modulate brain function by manipulation of KYNA formation in the brain. This approach may be useful in the treatment and prevention of neurological and psychiatric diseases associated with increased KYNA levels.

  18. The physiological significance of phenylacetic Acid in abscising cotton cotyledons.

    PubMed

    Suttle, J C; Mansager, E R

    1986-06-01

    The physiological role of phenylacetic acid (PAA) as an endogenous regulator of cotyledon abscission was examined using cotton (Gossypium hirsutum L. cv LG 102) seedlings. Application of 100 micromolar or more PAA to leafless cotyledon abscission-zone explants resulted in the retardation of petiole abscission and a decrease in the rise of ethylene evolution that normally accompanies aging of these explants in vitro. The partial inhibition of ethylene evolution in these explants by PAA was indirect since application of this compound stimulated short-term (<24 hours) ethylene production. PAA treatment partially suppressed the stimulation of petiole abscission elicited by either ethylene or abscisic acid. Both free and an acid-labile, bound form of PAA were identified in extracts prepared from cotyledons. No discernible pattern of changes in free or bound PAA was found during the course of ethylene-induced cotyledon abscission. Unlike indole-3-acetic acid, transport of PAA in isolated petiole segments was limited and exhibited little polarity. On the whole, these results are not consistent with the direct participation of PAA in the endogenous regulation of cotyledon abscission.

  19. Asiatic acid inhibits pulmonary inflammation induced by cigarette smoke.

    PubMed

    Lee, Jae-Won; Park, Hyun Ah; Kwon, Ok-Kyoung; Jang, Yin-Gi; Kim, Ju Yeong; Choi, Bo Kyung; Lee, Hee Jae; Lee, Sangwoo; Paik, Jin-Hyub; Oh, Sei-Ryang; Ahn, Kyung-Seop; Lee, Hyun-Jun

    2016-10-01

    Asiatic acid (AA) is one of the major components of Titrated extract of Centella asiatica (TECA), which has been reported to possess antioxidant and anti-inflammatory activities. The purpose of this study was to investigate the protective effect of AA on pulmonary inflammation induced by cigarette smoke (CS). AA significantly attenuated the infiltration of inflammatory cells in bronchoalveolar lavage fluid (BALF) of CS exposure mice. AA also decreased ROS production and NE activity, and inhibited the release of proinflammatory cytokines in BALF. AA reduced the recruitment of inflammatory cells and MCP-1 expression in lung tissue of CS exposure mice. AA also attenuated mucus overproduction, and decreased the activation of MAPKs and NF-kB in lung tissue. Furthermore, AA increased HO-1 expression and inhibited the reduced expression of SOD3 in lung tissue. These findings indicate that AA effectively inhibits pulmonary inflammatory response, which is an important process in the development of chronic obstructive pulmonary disease (COPD) via suppression of inflammatory mediators and induction of HO-1. Therefore, we suggest that AA has the potential to treat inflammatory disease such as COPD.

  20. Calcite crystal growth rate inhibition by polycarboxylic acids

    USGS Publications Warehouse

    Reddy, M.M.; Hoch, A.R.

    2001-01-01

    Calcite crystal growth rates measured in the presence of several polycarboxyclic acids show that tetrahydrofurantetracarboxylic acid (THFTCA) and cyclopentanetetracarboxylic acid (CPTCA) are effective growth rate inhibitors at low solution concentrations (0.01 to 1 mg/L). In contrast, linear polycarbocylic acids (citric acid and tricarballylic acid) had no inhibiting effect on calcite growth rates at concentrations up to 10 mg/L. Calcite crystal growth rate inhibition by cyclic polycarboxyclic acids appears to involve blockage of crystal growth sites on the mineral surface by several carboxylate groups. Growth morphology varied for growth in the absence and in the presence of both THFTCA and CPTCA. More effective growth rate reduction by CPTCA relative to THFTCA suggests that inhibitor carboxylate stereochemical orientation controls calcite surface interaction with carboxylate inhibitors. ?? 20O1 Academic Press.

  1. Perfluoroalkyl Acids Inhibit Reductive Dechlorination of Trichloroethene by Repressing Dehalococcoides.

    PubMed

    Weathers, Tess S; Harding-Marjanovic, Katie; Higgins, Christopher P; Alvarez-Cohen, Lisa; Sharp, Jonathan O

    2016-01-01

    The subsurface recalcitrance of perfluoroalkyl acids (PFAAs) derived from aqueous film-forming foams could have adverse impacts on the microbiological processes used for the bioremediation of co-mingled chlorinated solvents such as trichloroethene (TCE). Here, we show that reductive dechlorination by a methanogenic, mixed culture was significantly inhibited when exposed to concentrations representative of PFAA source zones (>66 mg/L total of 11 PFAA analytes, 6 mg/L each). TCE dechlorination, cis-dichloroethene and vinyl chloride production and dechlorination, and ethene generation were all inhibited at these PFAA concentrations. Phylogenetic analysis revealed that the abundances of 65% of the operational taxonomic units (OTUs) changed significantly when grown in the presence of PFAAs, although repression or enhancement resulting from PFAA exposure did not correlate with putative function or phylogeny. Notably, there was significant repression of Dehalococcoides (8-fold decrease in abundance) coupled with a corresponding enhancement of methane-generating Archaea (a 9-fold increase). Growth and dechlorination by axenic cultures of Dehalococcoides mccartyi strain 195 were similarly repressed under these conditions, confirming an inhibitory response of this pivotal genus to PFAA presence. These results suggest that chlorinated solvent bioattenuation rates could be impeded in subsurface environments near PFAA source zones. PMID:26636352

  2. Salicylic acid antagonizes abscisic acid inhibition of shoot growth and cell cycle progression in rice

    NASA Astrophysics Data System (ADS)

    Meguro, Ayano; Sato, Yutaka

    2014-04-01

    We analysed effects of abscisic acid (ABA, a negative regulatory hormone), alone and in combination with positive or neutral hormones, including salicylic acid (SA), on rice growth and expression of cell cycle-related genes. ABA significantly inhibited shoot growth and induced expression of OsKRP4, OsKRP5, and OsKRP6. A yeast two-hybrid assay showed that OsKRP4, OsKRP5, and OsKRP6 interacted with OsCDKA;1 and/or OsCDKA;2. When SA was simultaneously supplied with ABA, the antagonistic effect of SA completely blocked ABA inhibition. SA also blocked ABA inhibition of DNA replication and thymidine incorporation in the shoot apical meristem. These results suggest that ABA arrests cell cycle progression by inducing expression of OsKRP4, OsKRP5, and OsKRP6, which inhibit the G1/S transition, and that SA antagonizes ABA by blocking expression of OsKRP genes.

  3. Oleanolic acid and ursolic acid: novel hepatitis C virus antivirals that inhibit NS5B activity.

    PubMed

    Kong, Lingbao; Li, Shanshan; Liao, Qingjiao; Zhang, Yanni; Sun, Ruina; Zhu, Xiangdong; Zhang, Qinghua; Wang, Jun; Wu, Xiaoyu; Fang, Xiaonan; Zhu, Ying

    2013-04-01

    Hepatitis C virus (HCV) infects up to 170 million people worldwide and causes significant morbidity and mortality. Unfortunately, current therapy is only curative in approximately 50% of HCV patients and has adverse side effects, which warrants the need to develop novel and effective antivirals against HCV. We have previously reported that the Chinese herb Fructus Ligustri Lucidi (FLL) directly inhibited HCV NS5B RNA-dependent RNA polymerase (RdRp) activity (Kong et al., 2007). In this study, we found that the FLL aqueous extract strongly suppressed HCV replication. Further high-performance liquid chromatography (HPLC) analysis combined with inhibitory assays indicates that oleanolic acid and ursolic acid are two antiviral components within FLL aqueous extract that significantly suppressed the replication of HCV genotype 1b replicon and HCV genotype 2a JFH1 virus. Moreover, oleanolic acid and ursolic acid exhibited anti-HCV activity at least partly through suppressing HCV NS5B RdRp activity as noncompetitive inhibitors. Therefore, our results for the first time demonstrated that natural products oleanolic acid and ursolic acid could be used as potential HCV antivirals that can be applied to clinic trials either as monotherapy or in combination with other HCV antivirals. PMID:23422646

  4. Inhibition of plant fatty acid synthesis by nitroimidazoles.

    PubMed Central

    Jones, A V; Harwood, J L; Stratford, M R; Stumpf, P K

    1981-01-01

    1. The effect of the addition of a number of nitroimidazoles was tested on fatty acid synthesis by germinating pea seeds, isolated lettuce chloroplasts and a soluble fraction from pea seeds. 2. All the compounds tested had a marked inhibition on stearate desaturation by lettuce chloroplasts and on the synthesis of very-long-chain fatty acids by pea seeds. 3. In contrast, the effect of the drugs on total fatty acid synthesis from [14C]acetate in chloroplasts was related to the compound's electron reduction potentials. 4. Of the compounds used, only metronidazole had a marked inhibition on palmitate elongation in the systems tested. 5. The mechanism of inhibition of plant fatty acid synthesis by nitroimidazoles is discussed and the possible relevance of these findings to their neurotoxicity is suggested. PMID:7325993

  5. Monomethylarsonous acid inhibited endogenous cholesterol biosynthesis in human skin fibroblasts

    SciTech Connect

    Guo, Lei; Xiao, Yongsheng; Wang, Yinsheng

    2014-05-15

    Human exposure to arsenic in drinking water is a widespread public health concern, and such exposure is known to be associated with many human diseases. The detailed molecular mechanisms about how arsenic species contribute to the adverse human health effects, however, remain incompletely understood. Monomethylarsonous acid [MMA(III)] is a highly toxic and stable metabolite of inorganic arsenic. To exploit the mechanisms through which MMA(III) exerts its cytotoxic effect, we adopted a quantitative proteomic approach, by coupling stable isotope labeling by amino acids in cell culture (SILAC) with LC-MS/MS analysis, to examine the variation in the entire proteome of GM00637 human skin fibroblasts following acute MMA(III) exposure. Among the ∼ 6500 unique proteins quantified, ∼ 300 displayed significant changes in expression after exposure with 2 μM MMA(III) for 24 h. Subsequent analysis revealed the perturbation of de novo cholesterol biosynthesis, selenoprotein synthesis and Nrf2 pathways evoked by MMA(III) exposure. Particularly, MMA(III) treatment resulted in considerable down-regulation of several enzymes involved in cholesterol biosynthesis. In addition, real-time PCR analysis showed reduced mRNA levels of select genes in this pathway. Furthermore, MMA(III) exposure contributed to a distinct decline in cellular cholesterol content and significant growth inhibition of multiple cell lines, both of which could be restored by supplementation of cholesterol to the culture media. Collectively, the present study demonstrated that the cytotoxicity of MMA(III) may arise, at least in part, from the down-regulation of cholesterol biosynthesis enzymes and the resultant decrease of cellular cholesterol content. - Highlights: • MMA(III)-induced perturbation of the entire proteome of GM00637 cells is studied. • Quantitative proteomic approach revealed alterations of multiple cellular pathways. • MMA(III) inhibits de novo cholesterol biosynthesis. • MMA

  6. Phosphatidic acid inhibits blue light-induced stomatal opening via inhibition of protein phosphatase 1 [corrected].

    PubMed

    Takemiya, Atsushi; Shimazaki, Ken-ichiro

    2010-08-01

    Stomata open in response to blue light under a background of red light. The plant hormone abscisic acid (ABA) inhibits blue light-dependent stomatal opening, an effect essential for promoting stomatal closure in the daytime to prevent water loss. However, the mechanisms and molecular targets of this inhibition in the blue light signaling pathway remain unknown. Here, we report that phosphatidic acid (PA), a phospholipid second messenger produced by ABA in guard cells, inhibits protein phosphatase 1 (PP1), a positive regulator of blue light signaling, and PA plays a role in stimulating stomatal closure in Vicia faba. Biochemical analysis revealed that PA directly inhibited the phosphatase activity of the catalytic subunit of V. faba PP1 (PP1c) in vitro. PA inhibited blue light-dependent stomatal opening but did not affect red light- or fusicoccin-induced stomatal opening. PA also inhibited blue light-dependent H(+) pumping and phosphorylation of the plasma membrane H(+)-ATPase. However, PA did not inhibit the autophosphorylation of phototropins, blue light receptors for stomatal opening. Furthermore, 1-butanol, a selective inhibitor of phospholipase D, which produces PA via hydrolysis of phospholipids, diminished the ABA-induced inhibition of blue light-dependent stomatal opening and H(+) pumping. We also show that hydrogen peroxide and nitric oxide, which are intermediates in ABA signaling, inhibited the blue light responses of stomata and that 1-butanol diminished these inhibitions. From these results, we conclude that PA inhibits blue light signaling in guard cells by PP1c inhibition, accelerating stomatal closure, and that PP1 is a cross talk point between blue light and ABA signaling pathways in guard cells.

  7. Alkyl hydroxybenzoic acid derivatives that inhibit HIV-1 protease dimerization.

    PubMed

    Flausino, O A; Dufau, L; Regasini, L O; Petrônio, M S; Silva, D H S; Rose, T; Bolzani, V S; Reboud-Ravaux, M

    2012-01-01

    The therapeutic potential of gallic acid and its derivatives as anti-cancer, antimicrobial and antiviral agents is well known. We have examined the mechanism by which natural gallic acid and newly synthesized gallic acid alkyl esters and related protocatechuic acid alkyl esters inhibit HIV-1 protease to compare the influence of the aromatic ring substitutions on inhibition. We used Zhang-Poorman's kinetic analysis and fluorescent probe binding to demonstrate that several gallic and protecatechuic acid alkyl esters inhibited HIV-1 protease by preventing the dimerization of this obligate homodimeric aspartic protease rather than targeting the active site. The tri-hydroxy substituted benzoic moiety in gallates was more favorable than the di-substituted one in protocatechuates. In both series, the type of inhibition, its mechanism and the inhibitory efficiency dramatically depended on the length of the alkyl chain: no inhibition with alkyl chains less than 8 carbon atoms long. Molecular dynamics simulations corroborated the kinetic data and propose that gallic esters are intercalated between the two N- and C-monomer ends. They complete the β-sheet and disrupt the dimeric enzyme. The best gallic ester (14 carbon atoms, K(id) of 320 nM) also inhibited the multi-mutated protease MDR-HM. These results will aid the rational design of future generations of non-peptide inhibitors of HIV-1 protease dimerization that inhibit multi-mutated proteases. Finally, our work suggests the wide use of gallic and protocatechuic alkyl esters to dissociate intermolecular β-sheets involved in protein-protein interactions.

  8. Inhibition of Aeromonas caviae and A. sobria by sodium choloride, citric acid, ascorbic acid, potassium sorbate and extracts of Thymus vulgaris.

    PubMed

    Abu-Ghazaleh, B M

    2000-06-01

    The respective and combined effects of sodium chloride, ascorbic acid, citric acid, potassium sorbate, and Thymus vulgaris extract on the growth of Aeromonas caviae and Aeromonas sobria were investigated. Sodium chloride (3%) significantly reduced the growth and 4% NaCl inhibited growth of the tested strains. Ascorbic acid (0. 1%), potassium sorbate (0.05%), and citric acid (0.03%) slightly inhibited growth. T. vulgaris extract (0.3%) greatly reduced the growth. Various combinations of these compounds prevented growth of the tested strains. A combination of NaCl (3%) and ascorbic acid (0. 1%), citric acid (0.03%) and potassium sorbate (0.05%), or citric acid (0.03%) and ascorbic acid (0.1%) inhibited growth of A. caviae and A. sobria. In fish homogenates, the addition of ascorbic acid (0. 1%) and citric acid (0.03%) was the most effective combination tested.

  9. Eskimo plasma constituents, dihomo-gamma-linolenic acid, eicosapentaenoic acid and docosahexaenoic acid inhibit the release of atherogenic mitogens.

    PubMed

    Smith, D L; Willis, A L; Nguyen, N; Conner, D; Zahedi, S; Fulks, J

    1989-01-01

    Studies in man and laboratory animals suggest that omega 3 polyunsaturated fatty acid constituents of fish oils have antiatherosclerotic properties. We have studied the effects of several such polyunsaturated fatty acids for ability to modify the in vitro release of mitogens from human platelets. Such mitogens may produce the fibro-proliferative component of atherosclerotic plaques. Both 5,8,11,14,17-eicosapentaenoic acid (20:5 omega 3) and 4,7,10,13,16,19-docosahexaenoic acid (22:6 omega 3), major constituents of fish oils, inhibited adenosine diphosphate-induced aggregation of platelets and the accompanying release of mitogens. These effects are dose dependent. Linolenic acid (18:3 omega 3), the biosynthetic precursor of eicosapentaenoic acid, also inhibited platelet aggregation and mitogen release. Eicosapentaenoic acid also inhibited mitogen release from human monocyte-derived macrophages, which, in vivo, are an additional source of mitogens during atherogenesis. Potent inhibition of human platelet aggregation and mitogen release was also seen with dihomo-gamma-linolenic acid (8,11,14-eicosatrienoic acid 20:3 omega 6), whose levels are reportedly elevated in Eskimos subsisting on marine diets. We conclude that diets that elevate plasma and/or tissue levels of eicosapentaenoic acid, docosahexaenoic acid and dihomo-gamma-linolenic acid precursor gamma-linolenic acid (18:3 omega 6) may exert antiatherosclerotic effects by inhibiting the release of mitogens from platelets and other cells.

  10. Galacturonic Acid Inhibits the Growth of Saccharomyces cerevisiae on Galactose, Xylose, and Arabinose

    PubMed Central

    Huisjes, Eline H.; de Hulster, Erik; van Dam, Jan C.; Pronk, Jack T.

    2012-01-01

    The efficient fermentation of mixed substrates is essential for the microbial conversion of second-generation feedstocks, including pectin-rich waste streams such as citrus peel and sugar beet pulp. Galacturonic acid is a major constituent of hydrolysates of these pectin-rich materials. The yeast Saccharomyces cerevisiae, the main producer of bioethanol, cannot use this sugar acid. The impact of galacturonic acid on alcoholic fermentation by S. cerevisiae was investigated with anaerobic batch cultures grown on mixtures of glucose and galactose at various galacturonic acid concentrations and on a mixture of glucose, xylose, and arabinose. In cultures grown at pH 5.0, which is well above the pKa value of galacturonic acid (3.51), the addition of 10 g · liter−1 galacturonic acid did not affect galactose fermentation kinetics and growth. In cultures grown at pH 3.5, the addition of 10 g · liter−1 galacturonic acid did not significantly affect glucose consumption. However, at this lower pH, galacturonic acid completely inhibited growth on galactose and reduced galactose consumption rates by 87%. Additionally, it was shown that galacturonic acid strongly inhibits the fermentation of xylose and arabinose by the engineered pentose-fermenting S. cerevisiae strain IMS0010. The data indicate that inhibition occurs when nondissociated galacturonic acid is present extracellularly and corroborate the hypothesis that a combination of a decreased substrate uptake rate due to competitive inhibition on Gal2p, an increased energy requirement to maintain cellular homeostasis, and/or an accumulation of galacturonic acid 1-phosphate contributes to the inhibition. The role of galacturonic acid as an inhibitor of sugar fermentation should be considered in the design of yeast fermentation processes based on pectin-rich feedstocks. PMID:22582063

  11. Galacturonic acid inhibits the growth of Saccharomyces cerevisiae on galactose, xylose, and arabinose.

    PubMed

    Huisjes, Eline H; de Hulster, Erik; van Dam, Jan C; Pronk, Jack T; van Maris, Antonius J A

    2012-08-01

    The efficient fermentation of mixed substrates is essential for the microbial conversion of second-generation feedstocks, including pectin-rich waste streams such as citrus peel and sugar beet pulp. Galacturonic acid is a major constituent of hydrolysates of these pectin-rich materials. The yeast Saccharomyces cerevisiae, the main producer of bioethanol, cannot use this sugar acid. The impact of galacturonic acid on alcoholic fermentation by S. cerevisiae was investigated with anaerobic batch cultures grown on mixtures of glucose and galactose at various galacturonic acid concentrations and on a mixture of glucose, xylose, and arabinose. In cultures grown at pH 5.0, which is well above the pK(a) value of galacturonic acid (3.51), the addition of 10 g · liter(-1) galacturonic acid did not affect galactose fermentation kinetics and growth. In cultures grown at pH 3.5, the addition of 10 g · liter(-1) galacturonic acid did not significantly affect glucose consumption. However, at this lower pH, galacturonic acid completely inhibited growth on galactose and reduced galactose consumption rates by 87%. Additionally, it was shown that galacturonic acid strongly inhibits the fermentation of xylose and arabinose by the engineered pentose-fermenting S. cerevisiae strain IMS0010. The data indicate that inhibition occurs when nondissociated galacturonic acid is present extracellularly and corroborate the hypothesis that a combination of a decreased substrate uptake rate due to competitive inhibition on Gal2p, an increased energy requirement to maintain cellular homeostasis, and/or an accumulation of galacturonic acid 1-phosphate contributes to the inhibition. The role of galacturonic acid as an inhibitor of sugar fermentation should be considered in the design of yeast fermentation processes based on pectin-rich feedstocks. PMID:22582063

  12. Galacturonic acid inhibits the growth of Saccharomyces cerevisiae on galactose, xylose, and arabinose.

    PubMed

    Huisjes, Eline H; de Hulster, Erik; van Dam, Jan C; Pronk, Jack T; van Maris, Antonius J A

    2012-08-01

    The efficient fermentation of mixed substrates is essential for the microbial conversion of second-generation feedstocks, including pectin-rich waste streams such as citrus peel and sugar beet pulp. Galacturonic acid is a major constituent of hydrolysates of these pectin-rich materials. The yeast Saccharomyces cerevisiae, the main producer of bioethanol, cannot use this sugar acid. The impact of galacturonic acid on alcoholic fermentation by S. cerevisiae was investigated with anaerobic batch cultures grown on mixtures of glucose and galactose at various galacturonic acid concentrations and on a mixture of glucose, xylose, and arabinose. In cultures grown at pH 5.0, which is well above the pK(a) value of galacturonic acid (3.51), the addition of 10 g · liter(-1) galacturonic acid did not affect galactose fermentation kinetics and growth. In cultures grown at pH 3.5, the addition of 10 g · liter(-1) galacturonic acid did not significantly affect glucose consumption. However, at this lower pH, galacturonic acid completely inhibited growth on galactose and reduced galactose consumption rates by 87%. Additionally, it was shown that galacturonic acid strongly inhibits the fermentation of xylose and arabinose by the engineered pentose-fermenting S. cerevisiae strain IMS0010. The data indicate that inhibition occurs when nondissociated galacturonic acid is present extracellularly and corroborate the hypothesis that a combination of a decreased substrate uptake rate due to competitive inhibition on Gal2p, an increased energy requirement to maintain cellular homeostasis, and/or an accumulation of galacturonic acid 1-phosphate contributes to the inhibition. The role of galacturonic acid as an inhibitor of sugar fermentation should be considered in the design of yeast fermentation processes based on pectin-rich feedstocks.

  13. Protease inhibition by oleic acid transfer from chronic wound dressings to albumin.

    PubMed

    Edwards, J Vincent; Howley, Phyllis; Davis, Rachel; Mashchak, Andrew; Goheen, Steven C

    2007-08-01

    High elastase and cathepsin G activities have been observed in chronic wounds to inhibit healing through degradation of growth factors, cytokines, and extracellular matrix proteins. Oleic acid is a non-toxic elastase inhibitor. Cotton wound dressing material was characterized as a transfer carrier for affinity uptake of oleic acid by albumin under conditions mimicking chronic wounds. The mechanism of oleic acid uptake from cotton and binding by albumin was examined with both intact dressings and cotton fiber-designed chromatography. Raman spectra of the albumin-oleic acid complexes under liquid equilibrium conditions revealed fully saturated albumin-oleic acid complexes with a 1:1 weight ratio of albumin:oleic acid. Liquid-solid equilibrium conditions revealed oleic acid transfer from cotton to albumin at 27 mole equivalents of oleic acid per mole albumin. Comparing oleic acid formulated wound dressings for dose dependent ability to lower elastase activity, we found cotton gauze>hydrogel>hydrocolloid. In contrast, the cationic serine protease cathepsin G was inhibited by oleic acid within a narrow range of oleic acid-cotton formulations. 2% albumin was sufficient to transfer quantities of oleic acid necessary to achieve a significant elastase-lowering effect. Oleic acid bound to cotton wound dressings may have promise in the selective lowering of cationic serine protease activity useful in topical application for chronic inflammatory pathogenesis.

  14. Salicylic acid inhibits enzymatic browning of fresh-cut Chinese chestnut (Castanea mollissima) by competitively inhibiting polyphenol oxidase.

    PubMed

    Zhou, Dan; Li, Lin; Wu, Yanwen; Fan, Junfeng; Ouyang, Jie

    2015-03-15

    The inhibitory effect and associated mechanisms of salicylic acid (SA) on the browning of fresh-cut Chinese chestnut were investigated. Shelled and sliced chestnuts were immersed in different concentrations of an SA solution, and the browning of the chestnut surface and interior were inhibited. The activities of polyphenol oxidase (PPO) and peroxidase (POD) extracted from chestnuts were measured in the presence and absence of SA. SA at concentrations higher than 0.3g/L delayed chestnut browning by significantly inhibiting the PPO activity (P<0.01), and the POD activity was not significantly affected (P>0.05). The binding and inhibition modes of SA with PPO and POD, determined by AUTODOCK 4.2 and Lineweaver-Burk plots, respectively, established SA as a competitive inhibitor of PPO. PMID:25308637

  15. Salicylic acid inhibits enzymatic browning of fresh-cut Chinese chestnut (Castanea mollissima) by competitively inhibiting polyphenol oxidase.

    PubMed

    Zhou, Dan; Li, Lin; Wu, Yanwen; Fan, Junfeng; Ouyang, Jie

    2015-03-15

    The inhibitory effect and associated mechanisms of salicylic acid (SA) on the browning of fresh-cut Chinese chestnut were investigated. Shelled and sliced chestnuts were immersed in different concentrations of an SA solution, and the browning of the chestnut surface and interior were inhibited. The activities of polyphenol oxidase (PPO) and peroxidase (POD) extracted from chestnuts were measured in the presence and absence of SA. SA at concentrations higher than 0.3g/L delayed chestnut browning by significantly inhibiting the PPO activity (P<0.01), and the POD activity was not significantly affected (P>0.05). The binding and inhibition modes of SA with PPO and POD, determined by AUTODOCK 4.2 and Lineweaver-Burk plots, respectively, established SA as a competitive inhibitor of PPO.

  16. Inhibition of citrus fungal pathogens by using lactic acid bacteria.

    PubMed

    Gerez, C L; Carbajo, M S; Rollán, G; Torres Leal, G; Font de Valdez, G

    2010-08-01

    The effect of lactic acid bacteria (LAB) on pathogenic fungi was evaluated and the metabolites involved in the antifungal effect were characterized. Penicillium digitatum (INTA 1 to INTA 7) and Geotrichum citri-aurantii (INTA 8) isolated from decayed lemon from commercial packinghouses were treated with imazalil and guazatine to obtain strains resistant to these fungicides. The most resistant strains (4 fungal strains) were selected for evaluating the antifungal activity of 33 LAB strains, among which only 8 strains gave positive results. The antifungal activity of these LAB strains was related to the production of lactic acid, acetic acid, and phenyllactic acid (PLA). A central composite design and the response surface methodology were used to evaluate the inhibitory effect of the organic acids produced by the LAB cultures. The antifungal activity of lactic acid was directly related to its concentration; however, acetic acid and PLA showed a peak of activity at 52.5 and 0.8 mM, respectively, with inhibition rates similar to those obtained with Serenade((R)) (3.0 ppm) imazalil (50 ppm) and guazatine (50 ppm). Beyond the peak of activity, a reduction in effectiveness of both acetic acid and PLA was observed. Comparing the inhibition rate of the organic acids, PLA was about 66- and 600-fold more effective than acetic acid and lactic acid, respectively. This study presents evidences on the antifungal effect of selected LAB strains and their end products. Studies are currently being undertaken to evaluate the effectiveness in preventing postharvest diseases on citrus fruits. PMID:20722936

  17. Growth inhibition of Cronobacter spp. strains in reconstituted powdered infant formula acidified with organic acids supported by natural stomach acidity.

    PubMed

    Zhu, S; Schnell, S; Fischer, M

    2013-09-01

    Cronobacter is associated with outbreaks of rare, but life-threatening cases of meningitis, necrotizing enterocolitis, and sepsis in newborns. This study was conducted to determine the effect of organic acids on growth of Cronobacter in laboratory medium and reconstituted powdered infant formula (PIF) as well as the bacteriostatic effect of slightly acidified infant formula when combined with neonatal gastric acidity. Inhibitory effect of seven organic acids on four acid sensitive Cronobacter strains was determined in laboratory medium with broth dilution method at pH 5.0, 5.5 and 6.0. Acetic, butyric and propionic acids were most inhibitive against Cronobacter in the laboratory medium. The killing effect of these three acids was partially buffered in reconstituted PIF. Under neonatal gastric acid condition of pH 5.0, the slightly acidified formula which did not exert inhibition effect solely reduced significantly the Cronobacter populations. A synergistic effect of formula moderately acidified with organic acid combined with the physiological infant gastric acid was visible in preventing the rapid growth of Cronobacter in neonatal stomach. The study contributed to a better understanding of the inhibitory effect of organic acids on Cronobacter growth in different matrixes and provided new ideas in terms of controlling bacteria colonization and translocation by acidified formula.

  18. Mercaptoimidazolylpropionic acid hydrobromide. Inhibition of tadpole collagenase and related properties.

    PubMed

    Yankeelov, J A; Parish, H A; Spatola, A F

    1978-07-01

    A mercapto analogue of histidine (1), (RS)-2-mercapto-3-(5-imidazolyl)propionic acid (2), was prepared by treatment of (RS)-2-bromo-3-(5-imidazolyl)propionic acid with trithiocarbonate. Decomposition of the resulting intermediate with hydrochloric acid followed by Sephadex G-15 chromatography permitted isolation of 2 as a hydrobromide complex having unusual stability and properties as evidenced by IR and 1H NMR data. The potency of this complex in inhibiting tissue (Rana catesbiana) collagenase was estimated by radial diffusion assay. The amount of 2 required to produce 50% inhibition was 3.8 +/- 1.5 mM compared to 8.7 +/- 2.5 mM for cysteine. Preliminary tests of oxygen susceptibility, mutagenicity, and toxicity suggest that this substance may warrant study as a therapeutic agent for control of collagenase-linked corneal ulcerations. PMID:209189

  19. Theobromine Inhibits Uric Acid Crystallization. A Potential Application in the Treatment of Uric Acid Nephrolithiasis

    PubMed Central

    Grases, Felix; Rodriguez, Adrian; Costa-Bauza, Antonia

    2014-01-01

    Purpose To assess the capacity of methylxanthines (caffeine, theophylline, theobromine and paraxanthine) to inhibit uric acid crystallization, and to evaluate their potential application in the treatment of uric acid nephrolithiasis. Materials and Methods The ability of methylxathines to inhibit uric acid nucleation was assayed turbidimetrically. Crystal morphology and its modification due to the effect of theobromine were evaluated by scanning electron microscopy (SEM). The ability of theobromine to inhibit uric acid crystal growth on calculi fragments resulting from extracorporeal shock wave lithotripsy (ESWL) was evaluated using a flow system. Results The turbidimetric assay showed that among the studied methylxanthines, theobromine could markedly inhibit uric acid nucleation. SEM images showed that the presence of theobromine resulted in thinner uric acid crystals. Furthermore, in a flow system theobromine blocked the regrowth of post-ESWL uric acid calculi fragments. Conclusions Theobromine, a natural dimethylxanthine present in high amounts in cocoa, acts as an inhibitor of nucleation and crystal growth of uric acid. Therefore, theobromine may be clinically useful in the treatment of uric acid nephrolithiasis. PMID:25333633

  20. Inhibition of bacterial activity in acid mine drainage

    NASA Astrophysics Data System (ADS)

    Singh, Gurdeep; Bhatnagar, Miss Mridula

    1988-12-01

    Acid mine drainage water give rise to rapid growth and activity of an iron- and sulphur- oxidizing bacterium Thiobacillus ferrooxidians which greatly accelerate acid producing reactions by oxidation of pyrite material associated with coal and adjoining strata. The role of this bacterium in production of acid mine drainage is described. This study presents the data which demonstrate the inhibitory effect of certain organic acids, sodium benzoate, sodium lauryl sulphate, quarternary ammonium compounds on the growth of the acidophilic aerobic autotroph Thiobacillus ferrooxidians. In each experiment, 10 milli-litres of laboratory developed culture of Thiobacillus ferrooxidians was added to 250 milli-litres Erlenmeyer flask containing 90 milli-litres of 9-k media supplemented with FeSO4 7H2O and organic compounds at various concentrations. Control experiments were also carried out. The treated and untreated (control) samples analysed at various time intervals for Ferrous Iron and pH levels. Results from this investigation showed that some organic acids, sodium benzoate, sodium lauryl sulphate and quarternary ammonium compounds at low concentration (10-2 M, 10-50 ppm concentration levels) are effective bactericides and able to inhibit and reduce the Ferrous Iron oxidation and acidity formation by inhibiting the growth of Thiobacillus ferrooxidians is also discussed and presented

  1. Seizure control by decanoic acid through direct AMPA receptor inhibition.

    PubMed

    Chang, Pishan; Augustin, Katrin; Boddum, Kim; Williams, Sophie; Sun, Min; Terschak, John A; Hardege, Jörg D; Chen, Philip E; Walker, Matthew C; Williams, Robin S B

    2016-02-01

    The medium chain triglyceride ketogenic diet is an established treatment for drug-resistant epilepsy that increases plasma levels of decanoic acid and ketones. Recently, decanoic acid has been shown to provide seizure control in vivo, yet its mechanism of action remains unclear. Here we show that decanoic acid, but not the ketones β-hydroxybutryate or acetone, shows antiseizure activity in two acute ex vivo rat hippocampal slice models of epileptiform activity. To search for a mechanism of decanoic acid, we show it has a strong inhibitory effect on excitatory, but not inhibitory, neurotransmission in hippocampal slices. Using heterologous expression of excitatory ionotropic glutamate receptor AMPA subunits in Xenopus oocytes, we show that this effect is through direct AMPA receptor inhibition, a target shared by a recently introduced epilepsy treatment perampanel. Decanoic acid acts as a non-competitive antagonist at therapeutically relevant concentrations, in a voltage- and subunit-dependent manner, and this is sufficient to explain its antiseizure effects. This inhibitory effect is likely to be caused by binding to sites on the M3 helix of the AMPA-GluA2 transmembrane domain; independent from the binding site of perampanel. Together our results indicate that the direct inhibition of excitatory neurotransmission by decanoic acid in the brain contributes to the anti-convulsant effect of the medium chain triglyceride ketogenic diet. PMID:26608744

  2. Suppression of Spermatogenesis by Bisdichloroacetyldiamines Is Mediated by Inhibition of Testicular Retinoic Acid Biosynthesis

    PubMed Central

    Amory, John K.; Muller, Charles H.; Shimshoni, Jakob A.; Isoherranen, Nina; Paik, Jisun; Moreb, Jan S.; Amory, David W.; Evanoff, Ryan; Goldstein, Alex S.; Griswold, Michael D.

    2012-01-01

    The bisdichloroacetyldiamine WIN 18,446 reversibly inhibits spermatogenesis in many species, including humans; however, the mechanism by which WIN 18,446 functions is unknown. As retinoic acid is essential for spermatogenesis, we hypothesized that WIN 18,446 might inhibit retinoic acid biosynthesis from retinol (vitamin A) within the testes by inhibiting the enzyme aldehyde dehydrogenase 1a2 (ALDH1a2). We studied the effect of WIN 18,446 on ALDH1a2 enzyme activity in vitro, and on spermatogenesis and fertility in vivo, in mature male rabbits for 16 weeks. WIN 18,446 markedly inhibited ALDH1a2 enzyme activity in vitro with an IC50 of 0.3 μM. In vivo, the oral administration of 200 mg/kg WIN 18,446 to male rabbits for 16 weeks significantly reduced intratesticular concentrations of retinoic acid, severely impaired spermatogenesis, and caused infertility. Reduced concentrations of intratesticular retinoic acid were apparent after only 4 weeks of treatment and preceded the decrease in sperm counts and the loss of mature germ cells in tissue samples. Sperm counts and fertility recovered after treatment was discontinued. These findings demonstrate that bisdichloroacetyldiamines such as WIN 18,446 reversibly suppress spermatogenesis via inhibition of testicular retinoic acid biosynthesis by ALDH1a2. These findings suggest that ALDH1a2 is a promising target for the development of a reversible, nonhormonal male contraceptive. PMID:20705791

  3. Inhibition of the gravitropic bending response of flowering shoots by salicylic acid.

    PubMed

    Friedman, Haya; Meir, Shimon; Halevy, Abraham H; Philosoph-Hadas, Sonia

    2003-10-01

    The upward gravitropic bending of cut snapdragon, lupinus and anemone flowering shoots was inhibited by salicylic acid (SA) applied at 0.5 mM and above. This effect was probably not due to acidification of the cytoplasm, since other weak acids did not inhibit bending of snapdragon shoots. In order to study its mode of inhibitory action, we have examined in cut snapdragon shoots the effect of SA on three processes of the gravity-signaling pathway, including: amyloplast sedimentation, formation of ethylene gradient across the stem, and differential growth response. The results show that 1 mM SA inhibited differential ethylene production rates across the horizontal stem and the gravity-induced growth, without significantly inhibiting vertical growth or amyloplast sedimentation following horizontal placement. However, 5 mM SA inhibited all three gravity-induced processes, as well as the growth of vertical shoots, while increasing flower wilting. It may, therefore, be concluded that SA inhibits bending of various cut flowering shoots in a concentration-dependent manner. Thus, at a low concentration SA exerts its effect in snapdragon shoots by inhibiting processes operating downstream to stimulus sensing exerted by amyloplast sedimentation. At a higher concentration SA inhibits bending probably by exerting general negative effects on various cellular processes.

  4. Acid inhibition and infections outside the gastrointestinal tract.

    PubMed

    Vakil, Nimish

    2009-03-01

    Acid-inhibitory agents can alter the flora of the stomach, and epidemiologic studies suggest an association between the use of these agents and the development of pneumonia. Microbiologic studies suggest that a causal association may be biologically plausible because gastric colonization with organisms can occur in patients taking acid suppressive agents. In mechanically ventilated patients, colonization of the oropharynx and stomach may predispose to Gram-negative pneumonias. Despite the associations between acid inhibitor use and pneumonia shown in some studies, the data on community-acquired pneumonias are not conclusive. In clinical practice, prudence would dictate that the need for acid inhibition with histamine-2 receptor antagonists or proton pump inhibitors should be carefully considered in patients who are at risk for pneumonias (elderly patients with chronic lung disease who are on immunosuppressive drugs or corticosteroids and patients with recurrent lung infections requiring frequent antibiotic therapy).

  5. Biologic significance of polyunsaturated fatty acids in the skin.

    PubMed

    Ziboh, V A; Chapkin, R S

    1987-12-01

    Deficiency of essential fatty acid (EFA) containing linoleic acid (18:2n-6) in humans or animals induces morphologic changes characterized by severe scaly dermatosis, extensive percutaneous water loss, and hyperproliferation of the epidermis. Microscopically, the epidermis is characterized by hyperkeratosis and acanthosis. The refeeding of safflower oil containing linoleic acid or primrose oil (containing linoleic acid [18:2n-6] and gamma-linolenic acid [18:3n-6]) acids to EFA-deficient guinea pigs reverses the EFA-deficiency symptoms. In contrast, replacement of safflower oil with menhaden fish oil, (containing eicosapentaenoic acid [20:5n-3] and docosahexaenoic acid [22:6n-3]) did not reverse the symptoms of EFA deficiency. These results indicate: (1) that an understanding of the roles of vegetable or fish oil in skin must evolve from an understanding of the roles of each constituent n-6 or n-3 fatty acid, and (2) that the n-3 fatty acids may function to modulate the metabolism and function of the n-6 fatty acids in vivo.

  6. Kaurenoic Acid from Aralia continentalis Inhibits Biofilm Formation of Streptococcus mutans

    PubMed Central

    Jeong, Seung-Il; Kim, Beom-Su; Keum, Ki-Suk; Lee, Kwang-Hee; Kang, Sun-Young; Park, Bok-Im; Lee, Young-Rae; You, Yong-Ouk

    2013-01-01

    We isolated a single chemical compound from A. continentalis and identified it to be kaurenoic acid (KA) and investigated the influence of anticariogenic properties. Inhibitory effects of KA on cariogenic properties such as growth, acid production, biofilm formation, and the adherence of S. mutans were evaluated. Furthermore, real-time PCR analysis was performed to evaluate the influence of KA on the genetic expression of virulence factors. KA significantly inhibited the growth and acid production of S. mutans at 2–4 μg/mL and 4 μg/mL of KA, respectively. Furthermore, the adherence onto S-HAs was inhibited at 3-4 μg/mL of KA and biofilm formation was significantly inhibited when treated with 3 μg/mL KA and completely inhibited at 4 μg/mL. Also, the inhibitory effect of KA on biofilm formation was confirmed by SEM. In confocal laser scanning microscopy, bacterial viability gradually decreased by KA in a dose dependent manner. Real-time PCR analysis showed that the expressions of gtfB, gtfC, gbpB, spaP, brpA, relA, and vicR were significantly decreased in S. mutans when it was treated with KA. These results suggest that KA from A. continentalis may be a useful agent for inhibiting the cariogenic properties of S. mutans. PMID:23662113

  7. Inhibition of cardiac mitochondrial respiration by salicylic acid and acetylsalicylate.

    PubMed

    Nulton-Persson, Amy C; Szweda, Luke I; Sadek, Hesham A

    2004-11-01

    Acetylsalicylate, the active ingredient in aspirin, has been shown to be beneficial in the treatment and prevention of cardiovascular disease. Because of the increasing frequency with which salicylates are used, it is important to more fully characterize extra- and intracellular processes that are altered by these compounds. Evidence is provided that treatment of isolated cardiac mitochondria with salicylic acid and to a lesser extent acetylsalicylate resulted in an increase in the rate of uncoupled respiration. In contrast, both compounds inhibited ADP-dependent NADH-linked (state 3) respiration to similar degrees. Under the conditions of our experiments, loss in state 3 respiration resulted from inhibition of the Krebs cycle enzyme alpha-ketoglutarate dehydrogenase (KGDH). Kinetic analysis indicates that salicylic acid acts as a competitive inhibitor at the alpha-ketoglutarate binding site. In contrast, acetylsalicylate inhibited the enzyme in a noncompetitive fashion consistent with interaction with the alpha-ketoglutarate binding site followed by enzyme-catalyzed acetylation. The effects of salicylic acid and acetylsalicylate on cardiac mitochondrial function may contribute to the known cardioprotective effects of therapeutic doses of aspirin, as well as to the toxicity associated with salicylate overdose.

  8. Inhibition of miR-29 has a significant lipid-lowering benefit through suppression of lipogenic programs in liver.

    PubMed

    Kurtz, C Lisa; Fannin, Emily E; Toth, Cynthia L; Pearson, Daniel S; Vickers, Kasey C; Sethupathy, Praveen

    2015-01-01

    MicroRNAs (miRNAs) are important regulators and potential therapeutic targets of metabolic disease. In this study we show by in vivo administration of locked nucleic acid (LNA) inhibitors that suppression of endogenous miR-29 lowers plasma cholesterol levels by ~40%, commensurate with the effect of statins, and reduces fatty acid content in the liver by ~20%. Whole transcriptome sequencing of the liver reveals 883 genes dysregulated (612 down, 271 up) by inhibition of miR-29. The set of 612 down-regulated genes are most significantly over-represented in lipid synthesis pathways. Among the up-regulated genes are the anti-lipogenic deacetylase sirtuin 1 (Sirt1) and the anti-lipogenic transcription factor aryl hydrocarbon receptor (Ahr), the latter of which we demonstrate is a direct target of miR-29. In vitro radiolabeled acetate incorporation assays confirm that pharmacologic inhibition of miR-29 significantly reduces de novo cholesterol and fatty acid synthesis. Our findings indicate that miR-29 controls hepatic lipogenic programs, likely in part through regulation of Ahr and Sirt1, and therefore may represent a candidate therapeutic target for metabolic disorders such as dyslipidemia. PMID:26246194

  9. Inhibition of miR-29 has a significant lipid-lowering benefit through suppression of lipogenic programs in liver

    PubMed Central

    Kurtz, C. Lisa; Fannin, Emily E.; Toth, Cynthia L.; Pearson, Daniel S.; Vickers, Kasey C.; Sethupathy, Praveen

    2015-01-01

    MicroRNAs (miRNAs) are important regulators and potential therapeutic targets of metabolic disease. In this study we show by in vivo administration of locked nucleic acid (LNA) inhibitors that suppression of endogenous miR-29 lowers plasma cholesterol levels by ~40%, commensurate with the effect of statins, and reduces fatty acid content in the liver by ~20%. Whole transcriptome sequencing of the liver reveals 883 genes dysregulated (612 down, 271 up) by inhibition of miR-29. The set of 612 down-regulated genes are most significantly over-represented in lipid synthesis pathways. Among the up-regulated genes are the anti-lipogenic deacetylase sirtuin 1 (Sirt1) and the anti-lipogenic transcription factor aryl hydrocarbon receptor (Ahr), the latter of which we demonstrate is a direct target of miR-29. In vitro radiolabeled acetate incorporation assays confirm that pharmacologic inhibition of miR-29 significantly reduces de novo cholesterol and fatty acid synthesis. Our findings indicate that miR-29 controls hepatic lipogenic programs, likely in part through regulation of Ahr and Sirt1, and therefore may represent a candidate therapeutic target for metabolic disorders such as dyslipidemia. PMID:26246194

  10. Cinnamic acid increases lignin production and inhibits soybean root growth.

    PubMed

    Salvador, Victor Hugo; Lima, Rogério Barbosa; dos Santos, Wanderley Dantas; Soares, Anderson Ricardo; Böhm, Paulo Alfredo Feitoza; Marchiosi, Rogério; Ferrarese, Maria de Lourdes Lucio; Ferrarese-Filho, Osvaldo

    2013-01-01

    Cinnamic acid is a known allelochemical that affects seed germination and plant root growth and therefore influences several metabolic processes. In the present work, we evaluated its effects on growth, indole-3-acetic acid (IAA) oxidase and cinnamate 4-hydroxylase (C4H) activities and lignin monomer composition in soybean (Glycine max) roots. The results revealed that exogenously applied cinnamic acid inhibited root growth and increased IAA oxidase and C4H activities. The allelochemical increased the total lignin content, thus altering the sum and ratios of the p-hydroxyphenyl (H), guaiacyl (G), and syringyl (S) lignin monomers. When applied alone or with cinnamic acid, piperonylic acid (PIP, a quasi-irreversible inhibitor of C4H) reduced C4H activity, lignin and the H, G, S monomer content compared to the cinnamic acid treatment. Taken together, these results indicate that exogenously applied cinnamic acid can be channeled into the phenylpropanoid pathway via the C4H reaction, resulting in an increase in H lignin. In conjunction with enhanced IAA oxidase activity, these metabolic responses lead to the stiffening of the cell wall and are followed by a reduction in soybean root growth.

  11. Cinnamic acid increases lignin production and inhibits soybean root growth.

    PubMed

    Salvador, Victor Hugo; Lima, Rogério Barbosa; dos Santos, Wanderley Dantas; Soares, Anderson Ricardo; Böhm, Paulo Alfredo Feitoza; Marchiosi, Rogério; Ferrarese, Maria de Lourdes Lucio; Ferrarese-Filho, Osvaldo

    2013-01-01

    Cinnamic acid is a known allelochemical that affects seed germination and plant root growth and therefore influences several metabolic processes. In the present work, we evaluated its effects on growth, indole-3-acetic acid (IAA) oxidase and cinnamate 4-hydroxylase (C4H) activities and lignin monomer composition in soybean (Glycine max) roots. The results revealed that exogenously applied cinnamic acid inhibited root growth and increased IAA oxidase and C4H activities. The allelochemical increased the total lignin content, thus altering the sum and ratios of the p-hydroxyphenyl (H), guaiacyl (G), and syringyl (S) lignin monomers. When applied alone or with cinnamic acid, piperonylic acid (PIP, a quasi-irreversible inhibitor of C4H) reduced C4H activity, lignin and the H, G, S monomer content compared to the cinnamic acid treatment. Taken together, these results indicate that exogenously applied cinnamic acid can be channeled into the phenylpropanoid pathway via the C4H reaction, resulting in an increase in H lignin. In conjunction with enhanced IAA oxidase activity, these metabolic responses lead to the stiffening of the cell wall and are followed by a reduction in soybean root growth. PMID:23922685

  12. Contribution of cinnamic acid analogues in rosmarinic acid to inhibition of snake venom induced hemorrhage.

    PubMed

    Aung, Hnin Thanda; Furukawa, Tadashi; Nikai, Toshiaki; Niwa, Masatake; Takaya, Yoshiaki

    2011-04-01

    In our previous paper, we reported that rosmarinic acid (1) of Argusia argentea could neutralize snake venom induced hemorrhagic action. Rosmarinic acid (1) consists of two phenylpropanoids: caffeic acid (2) and 3-(3,4-dihydroxyphenyl)lactic acid (3). In this study, we investigated the structural requirements necessary for inhibition of snake venom activity through the use of compounds, which are structurally related to rosmarinic acid (1). By examining anti-hemorrhagic activity of cinnamic acid analogs against Protobothrops flavoviridis (Habu) venom, it was revealed that the presence of the E-enoic acid moiety (-CH=CH-COOH) was critical. Furthermore, among the compound tested, it was concluded that rosmarinic acid (1) (IC(50) 0.15 μM) was the most potent inhibitor against the venom.

  13. alpha-Lipoic acid inhibits inflammatory bone resorption by suppressing prostaglandin E2 synthesis.

    PubMed

    Ha, Hyunil; Lee, Jong-Ho; Kim, Ha-Neui; Kim, Hyun-Man; Kwak, Han Bok; Lee, Seungbok; Kim, Hong-Hee; Lee, Zang Hee

    2006-01-01

    alpha-Lipoic acid (LA) has been intensely investigated as a therapeutic agent for several pathological conditions, including diabetic polyneuropathy. In the present study, we examined the effects of LA on osteoclastic bone loss associated with inflammation. LA significantly inhibited IL-1-induced osteoclast formation in cocultures of mouse osteoblasts and bone marrow cells, but LA had only a marginal effect on osteoclastogenesis from bone marrow macrophages induced by receptor activator of NF-kappaB ligand (RANKL). LA inhibited both the sustained up-regulation of RANKL expression and the production of PGE2 induced by IL-1 in osteoblasts. In addition, treatment with either prostaglandin E2 (PGE2) or RANKL rescued IL-1-induced osteoclast formation inhibited by LA or NS398, a specific cyclooxygenase-2 (COX-2) inhibitor, in cocultures. LA blocked IL-1-induced PGE2 production even in the presence of arachidonic acid, without affecting the expression of COX-2 and membrane-bound PGE2 synthase. Dihydrolipoic acid (the reduced form of LA), but not LA, attenuated recombinant COX-2 activity in vitro. LA also inhibited osteoclast formation and bone loss induced by IL-1 and LPS in mice. Our results suggest that the reduced form of LA inhibits COX-2 activity, PGE2 production, and sustained RANKL expression, thereby inhibiting osteoclast formation and bone loss in inflammatory conditions.

  14. The significance of folic acid for epilepsy patients.

    PubMed

    Moore, James Layne

    2005-09-01

    The following is a comprehensive review of the current understanding of the many important roles of folic acid in the health of patients with epilepsy. A review of past and current literature reveals that folic acid plays important roles in the areas of hematology, neurology, development, and reproduction. Also highlighted are new areas for exploration.

  15. Inhibition of nitrogen fixation in alfalfa by arsenate, heavy metals, fluoride, and simulated Acid rain.

    PubMed

    Porter, J R; Sheridan, R P

    1981-07-01

    The acute effects of aqueous solutions of As, Cd, Cu, Pb, F, and Zn ions at concentrations from 0.01 to 100 micrograms per milliliter and solutions adjusted to pH 2 to 6 with nitric or sulfuric acid were studied with respect to acetylene reduction, net photosynthesis, respiration rate, and chlorophyll content in Vernal alfalfa (Medicago sativa L. cv. Vernal). The effects of the various treatments on acetylene reduction varied from no demonstrable effect by any concentration of F(-) and 42% inhibition by 100 micrograms Pb(2+) per milliliter, to 100% inhibition by 10 micrograms Cd(2+) per milliliter and 100 micrograms per milliliter As, Cu(2+), and Zn(2+) ions. Zn(2+) showed statistically significant inhibition of activity at 0.1 micrograms per milliliter. Acid treatments were not inhibitory above pH 2, at which pH nitric acid inhibited acetylene reduction activity more than did sulfuric acid. The inhibition of acetylene reduction by these ions was Zn(2+) > Cd(2+) > Cu(2+) > AsO(3) (-) > Pb(2+) > F(-). The sensitivity of acetylene reduction to the ions was roughly equal to the sensitivity of photosynthesis, respiration, and chlorophyll content when Pb(2+) was applied, but was 1,000 times more sensitive to Zn(2+). The relationship of the data to field conditions and industrial pollution is discussed.

  16. Inhibition of Nitrogen Fixation in Alfalfa by Arsenate, Heavy Metals, Fluoride, and Simulated Acid Rain

    PubMed Central

    Porter, John R.; Sheridan, Richard P.

    1981-01-01

    The acute effects of aqueous solutions of As, Cd, Cu, Pb, F, and Zn ions at concentrations from 0.01 to 100 micrograms per milliliter and solutions adjusted to pH 2 to 6 with nitric or sulfuric acid were studied with respect to acetylene reduction, net photosynthesis, respiration rate, and chlorophyll content in Vernal alfalfa (Medicago sativa L. cv. Vernal). The effects of the various treatments on acetylene reduction varied from no demonstrable effect by any concentration of F− and 42% inhibition by 100 micrograms Pb2+ per milliliter, to 100% inhibition by 10 micrograms Cd2+ per milliliter and 100 micrograms per milliliter As, Cu2+, and Zn2+ ions. Zn2+ showed statistically significant inhibition of activity at 0.1 micrograms per milliliter. Acid treatments were not inhibitory above pH 2, at which pH nitric acid inhibited acetylene reduction activity more than did sulfuric acid. The inhibition of acetylene reduction by these ions was Zn2+ > Cd2+ > Cu2+ > AsO3− > Pb2+ > F−. The sensitivity of acetylene reduction to the ions was roughly equal to the sensitivity of photosynthesis, respiration, and chlorophyll content when Pb2+ was applied, but was 1,000 times more sensitive to Zn2+. The relationship of the data to field conditions and industrial pollution is discussed. PMID:16661858

  17. Punicic Acid a Conjugated Linolenic Acid Inhibits TNFα-Induced Neutrophil Hyperactivation and Protects from Experimental Colon Inflammation in Rats

    PubMed Central

    Boussetta, Tarek; Raad, Houssam; Lettéron, Philippe; Gougerot-Pocidalo, Marie-Anne; Marie, Jean-Claude

    2009-01-01

    Background Neutrophils play a major role in inflammation by releasing large amounts of ROS produced by NADPH-oxidase and myeloperoxidase (MPO). The proinflammatory cytokine TNFα primes ROS production through phosphorylation of the NADPH-oxidase subunit p47phox on Ser345. Conventional anti-inflammatory therapies remain partially successful and may have side effects. Therefore, regulation of neutrophil activation by natural dietary components represents an alternative therapeutic strategy in inflammatory diseases such as inflammatory bowel diseases. The aim of this study was to assess the effect of punicic acid, a conjugated linolenic fatty acid from pomegranate seed oil on TNFα-induced neutrophil hyperactivation in vitro and on colon inflammation in vivo. Methodology and Principal Findings We analyzed the effect of punicic acid on TNFα-induced neutrophil upregulation of ROS production in vitro and on TNBS-induced rat colon inflammation. Results show that punicic acid inhibited TNFα-induced priming of ROS production in vitro while preserving formyl-methionyl-leucyl-phenylalanine (fMLP)-induced response. This effect was mediated by the inhibition of Ser345-p47phox phosphorylation and upstream kinase p38MAPK. Punicic acid also inhibited fMLP- and TNFα+fMLP-induced MPO extracellular release from neutrophils. In vivo experiments showed that punicic acid and pomegranate seed oil intake decreased neutrophil-activation and ROS/MPO-mediated tissue damage as measured by F2-isoprostane release and protected rats from TNBS-induced colon inflammation. Conclusions/Significance These data show that punicic acid exerts a potent anti-inflammatory effect through inhibition of TNFα-induced priming of NADPH oxidase by targeting the p38MAPKinase/Ser345-p47phox-axis and MPO release. This natural dietary compound may provide a novel alternative therapeutic strategy in inflammatory diseases such as inflammatory bowel diseases. PMID:19649246

  18. Elicidation by a H-2-receptor antagonist of the significance of mucosal histamine mobilization in exciting acid secretion.

    PubMed Central

    Lundell, L

    1975-01-01

    1. The consequence of H-2-receptor blockade for the secretory responses of the gastric mucosa to hormonal or cholinergic stimulation was studied in conscious rats with Heindenhain pouches or Pavlov pouches with the antrum retained or resected. 2. Metiamide almost completely abolished acid secretion induced by pentagastrin without altering significantly the amount of histamine excreted in the urine. Histamine mobilization on pentagastrin infusion determined in vitro, seemed to be larger during H-2-receptor blockade than with pentagastrin alone. 3. CCK-PZ mobilized mucosal histamine to a considerable extent; the secretory response to this hormone was completely abolished by H-2-receptor blockade. 4. Acid secretion in response to 2-deoxy-D-glucose was inhibited by H-2-receptor blockade in the presence or absence of the antrum; however the inhibition was less complete than with hormone-induced secretion. 5. The acid secretory response to 100 mg/kg of 2-deoxy-D-glucose appeared to be less susceptible to H-2-receptor blockade than that of 50-mg/kg of 2-deoxy-D-glucose. 6. Feeding induced a secretory response in the Pavlov pouch which initially was more effectively inhibited by H-2-receptor blockade than the response to 2-deoxy-D-glucose. In the absence of antral gastrin secretion by either stimulus was equally inhibited. 7. Methacholine-induced acid secretion was inhibited by infusion of the H-2-receptor antagonist, an inhibition that was absent when pentagastrin was concomitantly infused. 8. Although acid secretion induced by cholinergic stimuli was readily inhibited by the H-2-receptor antagonist, slight or nor inhibition was noted on pepsin secretion. 9. The role of histamine as a physiological stimulus for the parietal cell is discussed in view of the fact that the secretory effect of natural stimuli, known or demonstrated to mobilize mucosal histamine, is restrained by H-2-receptor blockade. PMID:49418

  19. Cadmium inhibits acid secretion in stimulated frog gastric mucosa

    SciTech Connect

    Gerbino, Andrea; Debellis, Lucantonio; Caroppo, Rosa; Curci, Silvana; Colella, Matilde

    2010-06-01

    Cadmium, a toxic environmental pollutant, affects the function of different organs such as lungs, liver and kidney. Less is known about its toxic effects on the gastric mucosa. The aim of this study was to investigate the mechanisms by which cadmium impacts on the physiology of gastric mucosa. To this end, intact amphibian mucosae were mounted in Ussing chambers and the rate of acid secretion, short circuit current (I{sub sc}), transepithelial potential (V{sub t}) and resistance (R{sub t}) were recorded in the continuous presence of cadmium. Addition of cadmium (20 {mu}M to 1 mM) on the serosal but not luminal side of the mucosae resulted in inhibition of acid secretion and increase in NPPB-sensitive, chloride-dependent short circuit current. Remarkably, cadmium exerted its effects only on histamine-stimulated tissues. Experiments with TPEN, a cell-permeant chelator for heavy metals, showed that cadmium acts from the intracellular side of the acid secreting cells. Furthermore, cadmium-induced inhibition of acid secretion and increase in I{sub sc} cannot be explained by an action on: 1) H{sub 2} histamine receptor, 2) Ca{sup 2+} signalling 3) adenylyl cyclase or 4) carbonic anhydrase. Conversely, cadmium was ineffective in the presence of the H{sup +}/K{sup +}-ATPase blocker omeprazole suggesting that the two compounds likely act on the same target. Our findings suggest that cadmium affects the functionality of histamine-stimulated gastric mucosa by inhibiting the H{sup +}/K{sup +}-ATPase from the intracellular side. These data shed new light on the toxic effect of this dangerous environmental pollutant and may result in new avenues for therapeutic intervention in acute and chronic intoxication.

  20. Inhibition of human copper trafficking by a small molecule significantly attenuates cancer cell proliferation.

    PubMed

    Wang, Jing; Luo, Cheng; Shan, Changliang; You, Qiancheng; Lu, Junyan; Elf, Shannon; Zhou, Yu; Wen, Yi; Vinkenborg, Jan L; Fan, Jun; Kang, Heebum; Lin, Ruiting; Han, Dali; Xie, Yuxin; Karpus, Jason; Chen, Shijie; Ouyang, Shisheng; Luan, Chihao; Zhang, Naixia; Ding, Hong; Merkx, Maarten; Liu, Hong; Chen, Jing; Jiang, Hualiang; He, Chuan

    2015-12-01

    Copper is a transition metal that plays critical roles in many life processes. Controlling the cellular concentration and trafficking of copper offers a route to disrupt these processes. Here we report small molecules that inhibit the human copper-trafficking proteins Atox1 and CCS, and so provide a selective approach to disrupt cellular copper transport. The knockdown of Atox1 and CCS or their inhibition leads to a significantly reduced proliferation of cancer cells, but not of normal cells, as well as to attenuated tumour growth in mouse models. We show that blocking copper trafficking induces cellular oxidative stress and reduces levels of cellular ATP. The reduced level of ATP results in activation of the AMP-activated protein kinase that leads to reduced lipogenesis. Both effects contribute to the inhibition of cancer cell proliferation. Our results establish copper chaperones as new targets for future developments in anticancer therapies.

  1. Inhibition of human copper trafficking by a small molecule significantly attenuates cancer cell proliferation

    NASA Astrophysics Data System (ADS)

    Wang, Jing; Luo, Cheng; Shan, Changliang; You, Qiancheng; Lu, Junyan; Elf, Shannon; Zhou, Yu; Wen, Yi; Vinkenborg, Jan L.; Fan, Jun; Kang, Heebum; Lin, Ruiting; Han, Dali; Xie, Yuxin; Karpus, Jason; Chen, Shijie; Ouyang, Shisheng; Luan, Chihao; Zhang, Naixia; Ding, Hong; Merkx, Maarten; Liu, Hong; Chen, Jing; Jiang, Hualiang; He, Chuan

    2015-12-01

    Copper is a transition metal that plays critical roles in many life processes. Controlling the cellular concentration and trafficking of copper offers a route to disrupt these processes. Here we report small molecules that inhibit the human copper-trafficking proteins Atox1 and CCS, and so provide a selective approach to disrupt cellular copper transport. The knockdown of Atox1 and CCS or their inhibition leads to a significantly reduced proliferation of cancer cells, but not of normal cells, as well as to attenuated tumour growth in mouse models. We show that blocking copper trafficking induces cellular oxidative stress and reduces levels of cellular ATP. The reduced level of ATP results in activation of the AMP-activated protein kinase that leads to reduced lipogenesis. Both effects contribute to the inhibition of cancer cell proliferation. Our results establish copper chaperones as new targets for future developments in anticancer therapies.

  2. Inhibition of Aluminum Oxyhydroxide Precipitation with Citric Acid

    SciTech Connect

    Dabbs, Daniel M.; Ramachandran, Usha; Lu, Sang; Liu, Jun; Wang, Li Q.; Aksay, Ilhan A.

    2005-12-06

    Citric acid has been shown to act as an agent for increasing the solubility of aluminum oxyhydroxides in aqueous solutions of high (>2.47 mol/mol) hydroxide-to-aluminum ratios. Conversely, citric acid also colloidally stabilizes particles in aqueous suspensions of aluminum-containing particles. Solutions of aluminum chloride, with and without citric acid added, were titrated with NaO(aq). The presence and size of particles were determined using quasi-elastic light scattering. In solutions that contained no citric acid, particles formed instantaneously when NaOH(aq) was added but these were observed to rapidly diminish in size, disappearing at OH/Al ratios below 2.5 mol/mol. When the OH/Al ratio was raised beyond 2.5 by addingmoreNaOH(aq), suspensions of colloidally stable particles formed. Large polycations containing 13 aluminum atoms were detected by 27Al solution NMR in citric-acid-free solutions with OH/Al ratios slightly lower than 2.5. In comparison, adding citric acid to solutions of aluminum chloride inhibited the formation of large aluminum-containing polycations. The absence of the polycations prevents or retards the subsequent formation of particles, indicating that the polycations, when present, act as seeds to the formation of new particles. Particles did not form in solutions with a citric acid/aluminum ratio of 0.8 until sufficient NaOH(aq) was added to raise the OH/Al ratio to 3.29. By comparison, lower amounts of citric acid did not prevent particles from forming but did retard the rate of growth.

  3. Inhibition of Escherichia coli growth and diaminopimelic acid epimerase by 3-chlorodiaminopimelic acid.

    PubMed Central

    Baumann, R J; Bohme, E H; Wiseman, J S; Vaal, M; Nichols, J S

    1988-01-01

    The diaminopimelic acid (DAP) analog, 3-chloro-DAP, was synthesized and tested as the racemic acid for antibacterial activity and for inhibition of DAP epimerase. 3-Chloro-DAP was a potent inhibitor of DAP epimerase purified from Escherichia coli (Ki = 200 nM), and it is argued that 3-chloro-DAP is converted to a tight-binding transition state analog at the active site of this enzyme. Furthermore, 3-chloro-DAP inhibited growth of two E. coli mutants. In one of the mutants known for supersusceptibility to beta-lactams, inhibition was not seen until the mid-log phase of growth, while in the other mutant, a DAP auxotroph, inhibition occurred much earlier. Growth inhibition was reversed by DAP in both strains. In the auxotroph, the reversal was specific for meso-DAP, indicating that DAP epimerase was the target for 3-chloro-DAP. Thus we suggest a novel mechanism of bacterial growth inhibition which depends on DAP epimerase inhibition by a DAP analog. PMID:3056252

  4. Ferrous iron oxidation by Thiobacillus ferrooxidans: inhibition with benzoic acid, sorbic acid and sodium lauryl sulfate

    SciTech Connect

    Onysko, S.J.

    1984-07-01

    Acid mine drainage is formed by the weathering or oxidation of pyritic material exposed during coal mining. The rate of pyritic material oxidation can be greatly accelerated by certain acidophilic bacteria such as Thiobacillus ferrooxidans which catalyse the oxidation of ferrous to ferric iron. A number of organic compounds, under laboratory conditions, can apparently inhibit both the oxidation of ferrous to ferric iron by T. ferrooxidans and the weathering of pyritic material by mixed cultures of acid mine drainage micro-organisms. Sodium lauryl sulphate (SLS), an anionic surfactant has proved effective in this respect. Benzoic acid, sorbic acid and SLS at low concentrations, each effectively inhibited bacterial oxidation of ferrous iron in batch cultures of T. ferrooxidans. The rate of chemical oxidation of ferrous iron in low pH, sterile, batch reactors was not substantially affected at the tested concentrations of any of the compounds.

  5. Boric acid application guidelines for intergranular corrosion inhibition

    SciTech Connect

    Piskor, S.R. . Nuclear Services Div.)

    1990-12-01

    A significant fraction of the operating Pressurized Water Reactor steam generators have used or are using boric acid as an inhibitor to control stress corrosion cracking, intergranular attack, or denting. Boric acid is applied on line, or by means of crevice flushing, low power soaks, or a combination of these methods. When boric acid is used, it is important to have knowledge about its chemical and physical properties, its effect on corrosion, and its correct application. The data on these subjects may be found in a diversity of sources, which are often not readily available or convenient to use. In addition, new information has recently become available. This report has been prepared and revised to be comprehensive treatise on boric acid relevant to its application in nuclear steam generators. Relevant boric acid information from 1987--89 has been added to provide the latest available data from laboratory testing and power plant application. 5 figs.

  6. Salicylic Acid Inhibits Synthesis of Proteinase Inhibitors in Tomato Leaves Induced by Systemin and Jasmonic Acid.

    PubMed Central

    Doares, S. H.; Narvaez-Vasquez, J.; Conconi, A.; Ryan, C. A.

    1995-01-01

    Salicylic acid (SA) and acetylsalicylic acid (ASA), previously shown to inhibit proteinase inhibitor synthesis induced by wounding, oligouronides (H.M. Doherty, R.R. Selvendran, D.J. Bowles [1988] Physiol Mol Plant Pathol 33: 377-384), and linolenic acid (H. Pena-Cortes, T. Albrecht, S. Prat, E.W. Weiler, L. Willmitzer [1993] Planta 191: 123-128), are shown here to be potent inhibitors of systemin-induced and jasmonic acid (JA)-induced synthesis of proteinase inhibitor mRNAs and proteins. The inhibition by SA and ASA of proteinase inhibitor synthesis induced by systemin and JA, as well as by wounding and oligosaccharide elicitors, provides further evidence that both oligosaccharide and polypeptide inducer molecules utilize the octadecanoid pathway to signal the activation of proteinase inhibitor genes. Tomato (Lycopersicon esculentum) leaves were pulse labeled with [35S]methionine, followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and the inhibitory effects of SA are shown to be specific for the synthesis of a small number of JA-inducible proteins that includes the proteinase inhibitors. Previous results have shown that SA inhibits the conversion of 13S-hydroperoxy linolenic acid to 12-oxo-phytodienoic acid, thereby inhibiting the signaling pathway by blocking synthesis of JA. Here we report that the inhibition of synthesis of proteinase inhibitor proteins and mRNAs by SA in both light and darkness also occurs at a step in the signal transduction pathway, after JA synthesis but preceding transcription of the inhibitor genes. PMID:12228577

  7. Hyperbaric hyperoxia reversibly inhibits erythrocyte phospholipid fatty acid turnover

    NASA Technical Reports Server (NTRS)

    Dise, Craig A.; Clark, James M.; Lambersten, Christian J.; Goodman, David B. P.

    1987-01-01

    The effect of hyperbaric hyperoxia on the acylation of membrane phospholipid was studied by measuring the rates of activation of exogenous tritiated oleic acid to acyl thioester and of transesterification of the thioester into membrane phospholipids in intact human erythrocytes obtained 1 h after an exposure of the subjects to a hyperbaric oxygen atmosphere (3.5 h, 100 pct O2, 3 ATA). Exposure to pure oxygen was found to inhibit both the acylation and transesterification reactions by more than 30 percent, with partial recovery detected 24 h later. On the other hand, no rate changes were observed when isolated membranes from the same batches of cells were used in similar experiments. It is suggested that the decrease in the incorporation of tritiated oleic acid after hyperbaric hyperoxia may reflect an early event in the pathogenesis of oxygen-induced cellular injury and that it may be a useful index for the assessment of the tolerance of tissues to hyperoxia.

  8. Behaviorally inhibited individuals demonstrate significantly enhanced conditioned response acquisition under non-optimal learning conditions.

    PubMed

    Holloway, J L; Allen, M T; Myers, C E; Servatius, R J

    2014-03-15

    Behavioral inhibition (BI) is an anxiety vulnerability factor associated with hypervigilance to novel stimuli, threat, and ambiguous cues. The progression from anxiety risk to a clinical disorder is unknown, although the acquisition of defensive learning and avoidance may be a critical feature. As the expression of avoidance is also central to anxiety development, the present study examined avoidance acquisition as a function of inhibited temperament using classical eyeblink conditioning. Individuals were classified as behaviorally inhibited (BI) or non-inhibited (NI) based on combined scores from the Adult and Retrospective Measures of Behavioural Inhibition (AMBI and RMBI, respectively). Acquisition was assessed using delay, omission, or yoked conditioning schedules of reinforcement. Omission training was identical to delay, except that the emission of an eyeblink conditioned response (CR) resulted in omission of the unconditioned airpuff stimulus (US) on that trial. Each subject in the yoked group was matched on total BI score to a subject in the omission group, and received the same schedule of CS and US delivery, resulting in a partial reinforcement training schedule. Delay conditioning elicited significantly more CRs compared to the omission and yoked contingencies, the latter two of which did not differ from each other. Thus, acquisition of an avoidance response was not apparent. BI individuals demonstrated enhanced acquisition overall, while partial reinforcement training significantly distinguished between BI and NI groups. Enhanced learning in BI may be a function of an increased defensive learning capacity, or sensitivity to uncertainty. Further work examining the influence of BI on learning acquisition is important for understanding individual differences in disorder etiology in anxiety vulnerable cohorts.

  9. Identification of self-growth-inhibiting compounds lauric acid and 7-(Z)-tetradecenoic acid from Helicobacter pylori.

    PubMed

    Yamashita, Shinpei; Igarashi, Masayuki; Hayashi, Chigusa; Shitara, Tetsuo; Nomoto, Akio; Mizote, Tomoko; Shibasaki, Masakatsu

    2015-06-01

    Helicobacter pylori growth medium is usually supplemented with horse serum (HS) or FCS. However, cyclodextrin derivatives or activated charcoal can replace serum. In this study, we purified self-growth-inhibiting (SGI) compounds from H. pylori growth medium. The compounds were recovered from porous resin, Diaion HP-20, which was added to the H. pylori growth medium instead of known supplements. These SGI compounds were also identified from 2,6-di-O-methyl-β-cyclodextrin, which was supplemented in a pleuropneumonia-like organisms broth. The growth-inhibiting compounds were identified as lauric acid (LA) and 7-(Z)-tetradecenoic acid [7-(Z)-TDA]. Although several fatty acids had been identified in H. pylori, these specific compounds were not previously found in this species. However, we confirmed that these fatty acids were universally present in the cultivation medium of the H. pylori strains examined in this study. A live/dead assay carried out without HS indicated that these compounds were bacteriostatic; however, no significant growth-inhibiting effect was observed against other tested bacterial species that constituted the indigenous bacterial flora. These findings suggested that LA and 7-(Z)-TDA might play important roles in the survival of H. pylori in human stomach epithelial cells. PMID:25767109

  10. Unusal pattern of product inhibition: batch acetic acid fermentation

    SciTech Connect

    Bar, R.; Gainer, J.L.; Kirwan, D.J.

    1987-04-20

    The limited tolerance of microorganisms to their metabolic products results in inhibited growth and product formation. The relationship between the specific growth rate, micro, and the concentration of an inhibitory product has been described by a number of mathematical models. In most cases, micro was found to be inversely proportional to the product concentration and invariably the rate of substrate utilization followed the same pattern. In this communication, the authors report a rather unusual case in which the formation rate of a product, acetic acid, increased with a decreasing growth rate of the microorganism, Acetobacter aceti. Apparently, a similar behavior was mentioned in a review report with respect to Clostridium thermocellum in a batch culture but was not published in the freely circulating literature. The fermentation of ethanol to acetic acid, C/sub 2/H/sub 5/OH + O/sub 2/ = CH/sub 3/COOH + H/sub 2/O is clearly one of the oldest known fermentations. Because of its association with the commercial production of vinegar it has been a subject of extensive but rather technically oriented studies. Suprisingly, the uncommon uncoupling between the inhibited microbial growth and the product formation appears to have been unnoticed. 13 references.

  11. Inhibition of acid sphingomyelinase by tricyclic antidepressants and analogons

    PubMed Central

    Beckmann, Nadine; Sharma, Deepa; Gulbins, Erich; Becker, Katrin Anne; Edelmann, Bärbel

    2014-01-01

    Amitriptyline, a tricyclic antidepressant, has been used in the clinic to treat a number of disorders, in particular major depression and neuropathic pain. In the 1970s the ability of tricyclic antidepressants to inhibit acid sphingomyelinase (ASM) was discovered. The enzyme ASM catalyzes the hydrolysis of sphingomyelin to ceramide. ASM and ceramide were shown to play a crucial role in a wide range of diseases, including cancer, cystic fibrosis, diabetes, Alzheimer's disease, and major depression, as well as viral (e.g., measles virus) and bacterial (e.g., Staphylococcus aureus, Pseudomonas aeruginosa) infections. Ceramide molecules may act in these diseases by the alteration of membrane biophysics, the self-association of ceramide molecules within the cell membrane and the ultimate formation of larger ceramide-enriched membrane domains/platforms. These domains were shown to serve the clustering of certain receptors such as CD95 and may also act in the above named diseases. The potential to block the generation of ceramide by inhibiting the ASM has opened up new therapeutic approaches for the treatment of these conditions. Since amitriptyline is one of the longest used clinical drugs and side effects are well studied, it could potentially become a cheap and easily accessible medication for patients suffering from these diseases. In this review, we aim to provide an overview of current in vitro and in vivo studies and clinical trials utilizing amitriptyline to inhibit ASM and contemplate possible future applications of the drug. PMID:25228885

  12. Abscisic acid inhibits root growth in Arabidopsis through ethylene biosynthesis.

    PubMed

    Luo, Xingju; Chen, Zhizhong; Gao, Junping; Gong, Zhizhong

    2014-07-01

    When first discovered in 1963, abscisic acid (ABA) was called abscisin II because it promotes abscission. Later, researchers found that ABA accelerates abscission via ethylene. In Arabidopsis, previous studies have shown that high concentrations of ABA inhibit root growth through ethylene signaling but not ethylene production. In the present study in Arabidopsis, we found that ABA inhibits root growth by promoting ethylene biosynthesis. The ethylene biosynthesis inhibitor L-α-(2-aminoethoxyvinyl)-glycine reduces ABA inhibition of root growth, and multiple mutants of ACS (1-aminocyclopropane-1-carboxylate synthase) are more resistant to ABA in terms of root growth than the wild-type is. Two ABA-activated calcium-dependent protein kinases, CPK4 and CPK11, phosphorylate the C-terminus of ACS6 and increase the stability of ACS6 in ethylene biosynthesis. Plants expressing an ACS6 mutant that mimics the phosphorylated form of ACS6 produce more ethylene than the wild-type. Our results reveal an important mechanism by which ABA promotes ethylene production. This mechanism may be highly conserved among higher plants.

  13. Inhibition of acid sensing ion channel by ligustrazine on angina model in rat.

    PubMed

    Zhang, Zhi-Gang; Zhang, Xiao-Lan; Wang, Xian-Yue; Luo, Zhu-Rong; Song, Jing-Chun

    2015-01-01

    Ligustrazine, a compound extracted from roots of Ligusticum chuanxiong, is widely used in Chinese traditional medicine to treat cardiac and cerebrovascular diseases and pain, including angina. The mechanism(s) of ligustrazine's effect to reduce angina is not clear. Angina is mediated by cardiac afferent sensory neurons. These neurons display a large acid-evoked depolarizing sodium current that can initiate action potentials in response to acidification that accompanies myocardial ischemia. Acid-sensing ion channels (ASICs) mediate this current. Here we tested the hypothesis that ligustrazine reduces ischemia-induced cardiac dysfunction and acid-evoked pain by an action to inhibit ASIC-mediated current. The effects of ligustrazine to attenuate ischemia-induced ST-segment depression, T wave changes, and myocardial infarct size in hearts of anesthetized rats were determined. Effects of ligustrazine on currents mediated by ASICs expressed in cultured Chinese hamster ovary cells, and effects of the drug on acid-induced nociceptive behavior and acid-induced currents in isolated dorsal root ganglions cells were measured. Ligustrazine significantly attenuated acid-induced ASIC currents, reduced cardiac ischemia-induced electrical dysfunction and infarct size, and decreased the nociceptive response to injection of acid into the paw of the rat hindlimb. The ASIC channel inhibitor A-317567 similarly reduced electrical dysfunction, infarct size, and nociceptive behavior in the rat. Inhibition of ASICs by ligustrazine may explain at least in part the beneficial effects of the drug that are observed in patients with ischemic heart disease and angina. PMID:26692925

  14. Neuraminidase inhibition of Dietary chlorogenic acids and derivatives - potential antivirals from dietary sources.

    PubMed

    Gamaleldin Elsadig Karar, Mohamed; Matei, Marius-Febi; Jaiswal, Rakesh; Illenberger, Susanne; Kuhnert, Nikolai

    2016-04-01

    Plants rich in chlorogenic acids (CGAs), caffeic acids and their derivatives have been found to exert antiviral effects against influenza virus neuroaminidase. In this study several dietary naturally occurring chlorogenic acids, phenolic acids and derivatives were screened for their inhibitory activity against neuroaminidases (NAs) from C. perfringens, H5N1 and recombinant H5N1 (N-His)-Tag using a fluorometric assay. There was no significant difference in inhibition between the different NA enzymes. The enzyme inhibition results indicated that chlorogenic acids and selected derivatives, exhibited high activities against NAs. It seems that the catechol group from caffeic acid was important for the activity. Dietary CGA therefore show promise as potential antiviral agents. However, caffeoyl quinic acids show low bioavailibility and are intensly metabolized by the gut micro flora, only low nM concentrations are observed in plasma and urine, therefore a systemic antiviral effect of these compounds is unlikely. Nevertheless, gut floral metabolites with a catechol moiety or structurally related dietary phenolics with a catechol moiety might serve as interesting compounds for future investigations. PMID:27010419

  15. Comparison of inhibition effects of some benzoic acid derivatives on sheep heart carbonic anhydrase

    NASA Astrophysics Data System (ADS)

    Kiliç, Deryanur; Yildiz, Melike; Şentürk, Murat; Erdoǧan, Orhan; Küfrevioǧlu, Ömer Irfan

    2016-04-01

    Carbonic anhydrase (CA) is a family of metalloenzymes that requires Zn as a cofactor and catalyze the quick conversion of CO2 to HCO3- and H+. Inhibitors of the carbonic anhydrases (CAs) have medical usage of significant diseases such as glaucoma, epilepsy, gastroduodenal ulcers, acid-base disequilibria and neurological disorders. In the present study, inhibition of CA with some benzoic derivatives (1-6) were investigated. Sheep heart CA (shCA) enzyme was isolated by means of designed affinity chromatography gel (cellulose-benzyl-sulfanylamide) 42.45-fold in a yield of 44 % with 564.65 EU/mg. Purified shCA enzyme was used in vitro studies. In the studies, IC50 values were calculated for 3-aminobenzoic acid (1), 4-aminobenzoic acid (2), 2-hydroxybenzoic acid (3), 2-benzoylbenzoic acid (4), 2,3-dimethoxybenzoic acid (5), and 3,4,5-trimethoxybenzoic acid (6), showing the inhibition effects on the purified enzyme. Such molecules can be used as pioneer for discovery of novel effective CA inhibitors for medicinal chemistry applications.

  16. Kinetic-spectrophotometric determination of ascorbic acid by inhibition of the hydrochloric acid-bromate reaction

    NASA Astrophysics Data System (ADS)

    Ensafi, Ali A.; Rezaei, B.; Movahedinia, H.

    2002-10-01

    A new analytical method was developed for the determination of ascorbic acid in fruit juice and pharmaceuticals. The method is based on its inhibition effect on the reaction between hydrochloric acid and bromate. The decolourisation of Methyl Orange by the reaction products was used to monitor the reaction spectrophotometrically at 510 nm. The linearity range of the calibration graph depends on bromate concentration. The variable affecting the rate of the reaction was investigated. The method is simple, rapid, relatively sensitive and precise. The limit of detection is 7.6×10 -6 M and calibration rang is 8×10 -6-1.2×10 -3 M ascorbic acid. The relative standard deviation of seven replication determinations of 8×10 -6 and 2×10 -5 M ascorbic acid was 2.8 and 1.7%, respectively. The influence of potential interfering substance was studied. The method was successfully applied for the determination of ascorbic acid in pharmaceuticals.

  17. Significance of bacterial flora in abdominal irradiation-induced inhibition of lung metastases

    SciTech Connect

    Matsumoto, T.; Ando, K.; Koike, S.

    1988-06-01

    We have previously reported that abdominal irradiation prior to i.v. injection of syngeneic tumor cells reduced metastases in lung. Our report described an investigation of the significance of intestinal organisms in the radiation effect. We found that eliminating intestinal organisms with antibiotics totally abolished the radiation effect. Monoassociation of germ-free mice revealed that the radiation effect was observable only for Enterobacter cloacae, never for Streptococcus faecium, Bifidobacterium adlesentis, or Escherichia coli. After abdominal irradiation of regular mice, E. cloacae multiplied in cecal contents, adhered to mucous membranes, invaded the cecal wall, and translocated to mesenteric lymph nodes. Intravenous administration of E. cloacae in place of abdominal irradiation inhibited metastases. E. cloacae-monoassociated mice developed fewer metastases than germ-free mice, and the reduction was further enhanced by abdominal irradiation. We concluded that abdominal irradiation caused the invasion of E. cloacae from the mucous membrane of the intestine and inhibited formation of lung metastases.

  18. Glycochenodeoxycholic acid inhibits calcium phosphate precipitation in vitro by preventing the transformation of amorphous calcium phosphate to calcium hydroxyapatite.

    PubMed Central

    Qiu, S M; Wen, G; Hirakawa, N; Soloway, R D; Hong, N K; Crowther, R S

    1991-01-01

    Calcium hydroxyapatite can be a significant component of black pigment gallstones. Diverse molecules that bind calcium phosphate inhibit hydroxyapatite precipitation. Because glycine-conjugated bile acids, but not their taurine counterparts, bind calcium phosphate, we studied whether glycochenodeoxycholic acid inhibits calcium hydroxyapatite formation. Glycochenodeoxycholic acid (2 mM) totally inhibited transformation of amorphous calcium phosphate microprecipitates to macroscopic crystalline calcium hydroxyapatite. This inhibition was not mediated by decreased Ca2+ activity. Taurocholic acid (2-12 mM) did not affect hydroxyapatite formation, but antagonized glycochenodeoxycholic acid. Both amorphous and crystalline precipitates contained a surface fraction relatively rich in phosphate. The surface phosphate content was diminish by increasing glycochenodeoxycholic acid concentrations, and this relationship was interpreted as competition between bile acid and HPO4(-4) for binding sites on the calcium phosphate surface. A phosphate-rich crystal surface was associated with rapid transition from amorphous to crystalline states. These results indicate that glycochenodeoxycholic acid prevents transformation of amorphous calcium phosphate to crystalline hydroxyapatite by competitively inhibiting the accumulation of phosphate on the crystal embryo surface. PMID:1655828

  19. Cinnamic acid amides from Tribulus terrestris displaying uncompetitive α-glucosidase inhibition.

    PubMed

    Song, Yeong Hun; Kim, Dae Wook; Curtis-Long, Marcus J; Park, Chanin; Son, Minky; Kim, Jeong Yoon; Yuk, Heung Joo; Lee, Keun Woo; Park, Ki Hun

    2016-05-23

    The α-glucosidase inhibitory potential of Tribulus terrestris extracts has been reported but as yet the active ingredients are unknown. This study attempted to isolate the responsible metabolites and elucidate their inhibition mechanism of α-glucosidase. By fractionating T. terristris extracts, three cinnamic acid amide derivatives (1-3) were ascertained to be active components against α-glucosidase. The lead structure, N-trans-coumaroyltyramine 1, showed significant inhibition of α-glucosidase (IC50 = 0.42 μM). Moreover, all active compounds displayed uncompetitive inhibition mechanisms that have rarely been reported for α-glucosidase inhibitors. This kinetic behavior was fully demonstrated by showing a decrease of both Km and Vmax, and Kik/Kiv ratio ranging between 1.029 and 1.053. We progressed to study how chemical modifications to the lead structure 1 may impact inhibition. An α, β-unsaturation carbonyl group and hydroxyl group in A-ring of cinnamic acid amide emerged to be critical functionalities for α-glucosidase inhibition. The molecular modeling study revealed that the inhibitory activities are tightly related to π-π interaction as well as hydrogen bond interaction between enzyme and inhibitors.

  20. Diuresis by intravenous administration of xanthurenic acid in rats, and inhibition by probenecid.

    PubMed

    Uwai, Yuichi; Nakashima, Yuta; Honjo, Emi; Kawasaki, Tatsuya; Nabekura, Tomohiro

    2014-01-01

    The conjugates with sulfate and glucoside of xanthurenic acid, a tryptophan metabolite, were reported to show natriuresis. Sulfotransferase for xanthurenic acid works in the renal proximal tubule to produce the sulfate of xanthurenic acid as well as the liver, and we recently found that xanthurenic acid is a substrate of renal organic anion transporter OAT1. The purpose of this study was to examine relationship between the transport by OAT1 and diuresis related with xanthurenic acid. Drug transport experiment using Xenopus laevis oocytes represented that probenecid inhibited xanthurenic acid uptake by rat OAT1 (rOAT1). Although no diuresis was recognized by the intravenous injection of xanthurenic acid as a bolus in rats, the addition of its infusion exhibited natriuresis. Simultaneous administration of probenecid significantly decreased the urine volume and excreted amounts of sodium into urine. These findings showed the diuresis by the xanthurenic acid administration, and it was probenecid-sensitive. The rOAT1-mediated transport of xanthurenic acid might, at least in part, contribute to its diuretic effect.

  1. Enhancement of taxol-induced apoptosis by inhibition of NF-κB with ursorlic acid

    NASA Astrophysics Data System (ADS)

    Li, Yunlong; Xing, Da

    2007-05-01

    Taxol is known to inhibit cell growth and triggers significant apoptosis in various cancer cells, and activation of proliferation factor NF-κB during Taxol-induced apoptosis is regarded as a main reason resulting in tumor cells resistance to Taxol. It has been found that ursorlic acid can inhibit the activation of NF-κB. In order to study whether ursorlic acid can enhance the Taxol-induced apoptosis, we use fluorescence resonance energy transfer (FRET) technique and probe SCAT3 to compare the difference of caspase-3 activation between Taxol alone and Taxol combined ursorlic acid. With laser scanning confocal microscopy, we find that ursorlic acid, a nontoxic food component, sensitizes ASTC-a-1 cells more efficiently to Taxol-induced apoptosis by advanced activation of caspase 3. The result also suggests that there would be a synergistic effect between Taxol and ursorlic acid, and the more detailed mechanism of synergistic effect needs to be clarified further, such as the correlations among NF-κB, Akt, caspase 8, which leads to the advanced activation of caspase 3 during combined treatment of Taxol and ursorlic acid. Moreover, this may be a new way to improve Taxol-dependent tumor therapy.

  2. Inhibition of Fatty Acid Synthesis Induces Apoptosis of Human Pancreatic Cancer Cells.

    PubMed

    Nishi, Koji; Suzuki, Kenta; Sawamoto, Junpei; Tokizawa, Yuma; Iwase, Yumiko; Yumita, Nagahiko; Ikeda, Toshihiko

    2016-09-01

    Cancer cells tend to have a high requirement for lipids, including fatty acids, cholesterol and triglyceride, because of their rapid proliferative rate compared to normal cells. In this study, we investigated the effects of inhibition of lipid synthesis on the proliferation and viability of human pancreatic cancer cells. Of the inhibitors of lipid synthesis that were tested, 5-(tetradecyloxy)-2-furoic acid (TOFA), which is an inhibitor of acetyl-CoA carboxylase, and the fatty acid synthase (FAS) inhibitors cerulenin and irgasan, significantly suppressed the proliferation of MiaPaCa-2 and AsPC-1 cells. Treatment of MiaPaCa-2 cells with these inhibitors significantly increased the number of apoptotic cells. In addition, TOFA increased caspase-3 activity and induced cleavage of poly (ADP-ribose) polymerase in MiaPaCa-2 cells. Moreover, addition of palmitate to MiaPaCa-2 cells treated with TOFA rescued cells from apoptotic cell death. These results suggest that TOFA induces apoptosis via depletion of fatty acids and that, among the various aspects of lipid metabolism, inhibition of fatty acid synthesis may be a notable target for the treatment of human pancreatic cancer cells. PMID:27630308

  3. Carnosic Acid Inhibits the Epithelial-Mesenchymal Transition in B16F10 Melanoma Cells: A Possible Mechanism for the Inhibition of Cell Migration

    PubMed Central

    Park, So Young; Song, Hyerim; Sung, Mi-Kyung; Kang, Young-Hee; Lee, Ki Won; Park, Jung Han Yoon

    2014-01-01

    Carnosic acid is a natural benzenediol abietane diterpene found in rosemary and exhibits anti-inflammatory, antioxidant, and anti-carcinogenic activities. In this study, we evaluated the effects of carnosic acid on the metastatic characteristics of B16F10 melanoma cells. When B16F10 cells were cultured in an in vitro Transwell system, carnosic acid inhibited cell migration in a dose-dependent manner. Carnosic acid suppressed the adhesion of B16F10 cells, as well as the secretion of matrix metalloproteinase (MMP)-9, tissue inhibitor of metalloproteinase (TIMP)-1, urokinase plasminogen activator (uPA), and vascular cell adhesion molecule (VCAM)-1. Interestingly, secretion of TIMP-2 increased significantly in B16F10 cells treated with 10 μmol/L carnosic acid. Additionally, carnosic acid suppressed the mesenchymal markers snail, slug, vimentin, and N-cadherin and induced epithelial marker E-cadherin. Furthermore, carnosic acid suppressed phosphorylation of Src, FAK, and AKT. These results indicate that inhibition of the epithelial-mesenchymal transition may be important for the carnosic acid-induced inhibition of B16F10 cell migration. PMID:25036034

  4. 4-Coumaroyl and caffeoyl shikimic acids inhibit 4-coumaric acid:coenzyme A ligases and modulate metabolic flux for 3-hydroxylation in monolignol biosynthesis of Populus trichocarpa.

    PubMed

    Lin, Chien-Yuan; Wang, Jack P; Li, Quanzi; Chen, Hsi-Chuan; Liu, Jie; Loziuk, Philip; Song, Jina; Williams, Cranos; Muddiman, David C; Sederoff, Ronald R; Chiang, Vincent L

    2015-01-01

    Downregulation of 4-coumaric acid:coenzyme A ligase (4CL) can reduce lignin content in a number of plant species. In lignin precursor (monolignol) biosynthesis during stem wood formation in Populus trichocarpa, two enzymes, Ptr4CL3 and Ptr4CL5, catalyze the coenzyme A (CoA) ligation of 4-coumaric acid to 4-coumaroyl-CoA and caffeic acid to caffeoyl-CoA. CoA ligation of 4-coumaric acid is essential for the 3-hydroxylation of 4-coumaroyl shikimic acid. This hydroxylation results from sequential reactions of 4-hydroxycinnamoyl-CoA:shikimic acid hydroxycinnamoyl transferases (PtrHCT1 and PtrHCT6) and 4-coumaric acid 3-hydroxylase 3 (PtrC3H3). Alternatively, 3-hydroxylation of 4-coumaric acid to caffeic acid may occur through an enzyme complex of cinnamic acid 4-hydroxylase 1 and 2 (PtrC4H1 and PtrC4H2) and PtrC3H3. We found that 4-coumaroyl and caffeoyl shikimic acids are inhibitors of Ptr4CL3 and Ptr4CL5. 4-Coumaroyl shikimic acid strongly inhibits the formation of 4-coumaroyl-CoA and caffeoyl-CoA. Caffeoyl shikimic acid inhibits only the formation of 4-coumaroyl-CoA. 4-Coumaroyl and caffeoyl shikimic acids both act as competitive and uncompetitive inhibitors. Metabolic flux in wild-type and PtrC3H3 downregulated P. trichocarpa transgenics has been estimated by absolute protein and metabolite quantification based on liquid chromatography-tandem mass spectrometry, mass action kinetics, and inhibition equations. Inhibition by 4-coumaroyl and caffeoyl shikimic acids may play significant regulatory roles when these inhibitors accumulate.

  5. Cannabinoids Inhibit Acid-Sensing Ion Channel Currents in Rat Dorsal Root Ganglion Neurons

    PubMed Central

    Qiu, Chun-Yu; Cai, Qi; Zou, Pengcheng; Wu, Heming; Hu, Wang-Ping

    2012-01-01

    Local acidosis has been found in various pain-generating conditions such as inflammation and tissue injury. Cannabinoids exert a powerful inhibitory control over pain initiation via peripheral cognate receptors. However, the peripheral molecular targets responsible for the antinociceptive effects of cannabinoids are still poorly understood. Here, we have found that WIN55,212-2, a cannabinoid receptor agonist, inhibits the activity of native acid-sensing ion channels (ASICs) in rat dorsal root ganglion (DRG) neurons. WIN55,212-2 dose-dependently inhibited proton-gated currents mediated by ASICs. WIN55,212-2 shifted the proton concentration–response curve downwards, with an decrease of 48.6±3.7% in the maximum current response but with no significant change in the EC50 value. The inhibition of proton-gated current induced by WIN55,212-2 was almost completely blocked by the selective CB1 receptor antagonist AM 281, but not by the CB2 receptor antagonist AM630. Pretreatment of forskolin, an AC activator, and the addition of cAMP also reversed the inhibition of WIN55,212-2. Moreover, WIN55,212-2 altered acid-evoked excitability of rat DRG neurons and decreased the number of action potentials induced by acid stimuli. Finally, WIN55,212-2 attenuated nociceptive responses to injection of acetic acid in rats. These results suggest that WIN55,212-2 inhibits the activity of ASICs via CB1 receptor and cAMP dependent pathway in rat primary sensory neurons. Thus, cannabinoids can exert their analgesic action by interaction with ASICs in the primary afferent neurons, which was novel analgesic mechanism of cannabinoids. PMID:23029075

  6. Inhibition of the Hematopoietic Protein Tyrosine Phosphatase by Phenoxyacetic Acids.

    PubMed

    Bobkova, Ekaterina V; Liu, Wallace H; Colayco, Sharon; Rascon, Justin; Vasile, Stefan; Gasior, Carlton; Critton, David A; Chan, Xochella; Dahl, Russell; Su, Ying; Sergienko, Eduard; Chung, Thomas D Y; Mustelin, Tomas; Page, Rebecca; Tautz, Lutz

    2011-02-01

    Protein tyrosine phosphatases (PTPs) have only recently become the focus of attention in the search for novel drug targets despite the fact that they play vital roles in numerous cellular processes and are implicated in many human diseases. The hematopoietic protein tyrosine phosphatase (HePTP) is often found dysregulated in preleukemic myelodysplastic syndrome (MDS), as well as in acute myelogenous leukemia (AML). Physiological substrates of HePTP include the mitogen-activated protein kinases (MAPKs) ERK1/2 and p38. Specific modulators of HePTP catalytic activity will be useful for elucidating mechanisms of MAPK regulation in hematopietic cells, and may also provide treatments for hematopoietic malignancies such as AML. Here we report the discovery of phenoxyacetic acids as inhibitors of HePTP. Structure-activity relationship (SAR) analysis and in silico docking studies reveal the molecular basis of HePTP inhibition by these compounds. We also show that these compounds are able to penetrate cell membranes and inhibit HePTP in human T lymphocytes.

  7. Inhibition of tumor-stromal interaction through HGF/Met signaling by valproic acid

    SciTech Connect

    Matsumoto, Yohsuke; Motoki, Takahiro; Kubota, Satoshi; Takigawa, Masaharu; Tsubouchi, Hirohito; Gohda, Eiichi

    2008-02-01

    Hepatocyte growth factor (HGF), which is produced by surrounding stromal cells, including fibroblasts and endothelial cells, has been shown to be a significant factor responsible for cancer cell invasion mediated by tumor-stromal interactions. We found in this study that the anti-tumor agent valproic acid (VPA), a histone deacetylase (HDAC) inhibitor, strongly inhibited tumor-stromal interaction. VPA inhibited HGF production in fibroblasts induced by epidermal growth factor (EGF), platelet-derived growth factor, basic fibroblast growth factor, phorbol 12-myristate 13-acetate (PMA) and prostaglandin E{sub 2} without any appreciable cytotoxic effect. Other HDAC inhibitors, including butyric acid and trichostatin A (TSA), showed similar inhibitory effects on HGF production stimulated by various inducers. Up-regulations of HGF gene expression induced by PMA and EGF were also suppressed by VPA and TSA. Furthermore, VPA significantly inhibited HGF-induced invasion of HepG2 hepatocellular carcinoma cells. VPA, however, did not affect the increases in phosphorylation of MAPK and Akt in HGF-treated HepG2 cells. These results demonstrated that VPA inhibited two critical processes of tumor-stromal interaction, induction of fibroblastic HGF production and HGF-induced invasion of HepG2 cells, and suggest that those activities serve for other anti-tumor mechanisms of VPA besides causing proliferation arrest, differentiation, and/or apoptosis of tumor cells.

  8. Prognostic Significance of Uric Acid Levels in Ischemic Stroke Patients.

    PubMed

    Zhang, Xia; Huang, Zhi-Chao; Lu, Tao-Sheng; You, Shou-Jiang; Cao, Yong-Jun; Liu, Chun-Feng

    2016-01-01

    The importance and function of serum uric acid (UA) levels in patients with cardiovascular disease or stroke are unclear. We sought to evaluate the appropriate UA levels for stroke patients and the association between endogenous UA levels and clinical outcomes in acute ischemic stroke (AIS) patients, particularly regarding the possible interaction between gender and UA levels with respect to AIS prognosis. We examined 303 patients who had an onset of ischemic stroke within 48 h. Of those, 101 patients received thrombolytic treatment. Serum UA (μmol/L) levels were measured the second morning after admission. Patient prognosis was evaluated 90 days after clinical onset by modified Rankin Scale. Patients were divided into four groups according to serum UA quartiles. A binary multivariate logistic regression model was used to assess clinical relevance in regard to functional outcome and endogenous UA levels. Analysis of subgroups by gender and normal glomerular filtration rate were also been done. Poor functional outcome was associated with older age, history of atrial fibrillation, or higher baseline National Institutes of Health Stroke Scale scores. After adjustment for potential confounders, patients with higher UA levels (>380 μmol/L) or lower UA levels (≤250 μmol/L) were 2-3 times more likely to have a poor outcome (OR 2.95, 95% CI 1.14-7.61; OR 2.78, 95% CI 1.02-7.58, respectively) compared to the baseline group (UA level 316-380 μmol/L). The same results were observed in thrombolyzed patients. Patients with high and low UA levels were 9-18 times more likely to having poor outcomes compared to the baseline group (UA level: 316-380 μmol/L; OR 18.50, 95% CI: 2.041-167.67; OR 9.66, 95% CI 1.42-65.88, respectively). In men, patients with high UA levels were 6 times more likely to have poor outcomes compared to the baseline group (UA level: 279-334 μmol/L; OR 6.10, 95% CI 1.62-22.93). However, female patients with UA level 271-337 μmol/L were seven times more

  9. Cinnamic acid and its derivatives inhibit fructose-mediated protein glycation.

    PubMed

    Adisakwattana, Sirichai; Sompong, Weerachat; Meeprom, Aramsri; Ngamukote, Sathaporn; Yibchok-Anun, Sirintorn

    2012-01-01

    Cinnamic acid and its derivatives have shown a variety of pharmacologic properties. However, little is known about the antiglycation properties of cinnamic acid and its derivatives. The present study sought to characterize the protein glycation inhibitory activity of cinnamic acid and its derivatives in a bovine serum albumin (BSA)/fructose system. The results demonstrated that cinnamic acid and its derivatives significantly inhibited the formation of advanced glycation end products (AGEs) by approximately 11.96-63.36% at a concentration of 1 mM. The strongest inhibitory activity against the formation of AGEs was shown by cinnamic acid. Furthermore, cinnamic acid and its derivatives reduced the level of fructosamine, the formation of N(ɛ)-(carboxymethyl) lysine (CML), and the level of amyloid cross β-structure. Cinnamic acid and its derivatives also prevented oxidative protein damages, including effects on protein carbonyl formation and thiol oxidation of BSA. Our findings may lead to the possibility of using cinnamic acid and its derivatives for preventing AGE-mediated diabetic complications.

  10. Hydroxamic acid derivatives of mycophenolic acid inhibit histone deacetylase at the cellular level.

    PubMed

    Batovska, Daniela I; Kim, Dong Hoon; Mitsuhashi, Shinya; Cho, Yoon Sun; Kwon, Ho Jeong; Ubukata, Makoto

    2008-10-01

    Mycophenolic acid (MPA, 1), an inhibitor of IMP-dehydrogenase (IMPDH) and a latent PPARgamma agonist, is used as an effective immunosuppressant for clinical transplantation and recently entered clinical trials in advanced multiple myeloma patients. On the other hand, suberoylanilide hydroxamic acid (SAHA), a non-specific histone deacetylase (HDAC) inhibitor, has been approved for treating cutaneous T-cell lymphoma. MPA seemed to bear a cap, a linker, and a weak metal-binding site as a latent inhibitor of HDAC. Therefore, the hydroxamic acid derivatives of mycophenolic acid having an effective metal-binding site, mycophenolic hydroxamic acid (MPHA, 2), 7-O-acetyl mycophenolic acid (7-O-Ac MPHA, 3), and 7-O-lauroyl mycophenolic hydroxamic acid (7-O-L MPHA, 4) were designed and synthesized. All these compounds inhibited histone deacetylase with IC50 values of 1, 0.9 and 0.5 microM, and cell proliferation at concentrations of 2, 1.5 and 1 microM, respectively. PMID:18838793

  11. Acupuncture inhibits vagal gastric acid secretion stimulated by sham feeding in healthy subjects.

    PubMed Central

    Lux, G; Hagel, J; Bäcker, P; Bäcker, G; Vogl, R; Ruppin, H; Domschke, S; Domschke, W

    1994-01-01

    In a prospective randomised study, the effect of acupuncture on sham feeding stimulated gastric acid secretion was investigated. In eight healthy volunteers (five men, three women, mean (SEM) age 26.3 (4.7) years) various methods of acupuncture were performed. Apart from the sham procedure, the acupuncture was performed at the classic acupuncture points. Electroacupuncture reduced gastric acid secretion expressed as median (range) significantly during the first 30 minute period to 1.6 (0-5.2) mmol compared with 3.8 (2.3-14.5) mmol (p < 0.05) during control period (sham feeding without acupuncture). Inhibition of gastric acid secretion by electroacupuncture was also significant during the second 30 minute period (0.2 (0-5.6) v 3.6 (0.3-9.1) mmol; p < 0.05) and for peak acid output (0.8 (0.2-5.1) v 7.6 (3.4-12.1) mmol; p < 0.05). Transcutaneous electrical nerve stimulation also resulted in significant reduction of gastric acid secretion during the first 30 minute period (1.0 (0-3.6) mmol v 3.8 (2.3-14.5) mmol; p < 0.05), and peak acid output (3.6 (1.2-12.0) v 7.6 (3.4-12.1) mmol; p < 0.05). The classic needle acupuncture, laser acupuncture, and sham acupuncture had no significant effect on gastric acid secretion. This study shows firstly that in healthy volunteers, only the versions of acupuncture using more pronounced stimulation (electroacupuncture, transcutaneous electrical nerve stimulation), but not those with only mild stimulation of the nerves (classic needle acupuncture, laser acupuncture), and secondly only acupuncture performed at defined points lead to significant reduction in gastric acid secretion. PMID:7926899

  12. Acupuncture inhibits vagal gastric acid secretion stimulated by sham feeding in healthy subjects.

    PubMed

    Lux, G; Hagel, J; Bäcker, P; Bäcker, G; Vogl, R; Ruppin, H; Domschke, S; Domschke, W

    1994-08-01

    In a prospective randomised study, the effect of acupuncture on sham feeding stimulated gastric acid secretion was investigated. In eight healthy volunteers (five men, three women, mean (SEM) age 26.3 (4.7) years) various methods of acupuncture were performed. Apart from the sham procedure, the acupuncture was performed at the classic acupuncture points. Electroacupuncture reduced gastric acid secretion expressed as median (range) significantly during the first 30 minute period to 1.6 (0-5.2) mmol compared with 3.8 (2.3-14.5) mmol (p < 0.05) during control period (sham feeding without acupuncture). Inhibition of gastric acid secretion by electroacupuncture was also significant during the second 30 minute period (0.2 (0-5.6) v 3.6 (0.3-9.1) mmol; p < 0.05) and for peak acid output (0.8 (0.2-5.1) v 7.6 (3.4-12.1) mmol; p < 0.05). Transcutaneous electrical nerve stimulation also resulted in significant reduction of gastric acid secretion during the first 30 minute period (1.0 (0-3.6) mmol v 3.8 (2.3-14.5) mmol; p < 0.05), and peak acid output (3.6 (1.2-12.0) v 7.6 (3.4-12.1) mmol; p < 0.05). The classic needle acupuncture, laser acupuncture, and sham acupuncture had no significant effect on gastric acid secretion. This study shows firstly that in healthy volunteers, only the versions of acupuncture using more pronounced stimulation (electroacupuncture, transcutaneous electrical nerve stimulation), but not those with only mild stimulation of the nerves (classic needle acupuncture, laser acupuncture), and secondly only acupuncture performed at defined points lead to significant reduction in gastric acid secretion.

  13. The CO2 inhibition of terrestrial isoprene emission significantly affects future ozone projections

    NASA Astrophysics Data System (ADS)

    Young, P. J.; Arneth, A.; Schurgers, G.; Zeng, G.; Pyle, J. A.

    2008-11-01

    Simulations of future tropospheric composition often include substantial increases in biogenic isoprene emissions arising from the Arrhenius-like leaf emission response and warmer surface temperatures, and from enhanced vegetation productivity in response to temperature and atmospheric CO2 concentration. However, a number of recent laboratory and field data have suggested a direct inhibition of leaf isoprene production by increasing atmospheric CO2 concentration, notwithstanding isoprene being produced from precursor molecules that include some of the primary products of carbon assimilation. The cellular mechanism that underlies the decoupling of leaf photosynthesis and isoprene production still awaits a full explanation but accounting for this observation in a dynamic vegetation model that contains a semi-mechanistic treatment of isoprene emissions has been shown to change future global isoprene emission estimates notably. Here we use these estimates in conjunction with a chemistry-climate model to compare the effects of isoprene simulations without and with a direct CO2-inhibition on late 21st century O3 and OH levels. The impact on surface O3 was significant. Including the CO2-inhibition of isoprene resulted in opposing responses in polluted (O3 decreases of up to 10 ppbv) vs. less polluted (O3 increases of up to 10 ppbv) source regions, due to isoprene nitrate and peroxy acetyl nitrate (PAN) chemistry. OH concentration increased with relatively lower future isoprene emissions, decreasing methane lifetime by ~7 months. Our simulations underline the large uncertainties in future chemistry and climate studies due to biogenic emission patterns and emphasize the problems of using globally averaged climate metrics to quantify the atmospheric impact of reactive, heterogeneously distributed substances.

  14. The CO2 inhibition of terrestrial isoprene emission significantly affects future ozone projections

    NASA Astrophysics Data System (ADS)

    Young, P. J.; Arneth, A.; Schurgers, G.; Zeng, G.; Pyle, J. A.

    2009-04-01

    Simulations of future tropospheric composition often include substantial increases in biogenic isoprene emissions arising from the Arrhenius-like leaf emission response and warmer surface temperatures, and from enhanced vegetation productivity in response to temperature and atmospheric CO2 concentration. However, a number of recent laboratory and field data have suggested a direct inhibition of leaf isoprene production by increasing atmospheric CO2 concentration, notwithstanding isoprene being produced from precursor molecules that include some of the primary products of carbon assimilation. The cellular mechanism that underlies the decoupling of leaf photosynthesis and isoprene production still awaits a full explanation but accounting for this observation in a dynamic vegetation model that contains a semi-mechanistic treatment of isoprene emissions has been shown to change future global isoprene emission estimates notably. Here we use these estimates in conjunction with a chemistry-climate model to compare the effects of isoprene simulations without and with a direct CO2-inhibition on late 21st century O3 and OH levels. The impact on surface O3 was significant. Including the CO2-inhibition of isoprene resulted in opposing responses in polluted (O3 decreases of up to 10 ppbv) vs. less polluted (O3 increases of up to 10 ppbv) source regions, due to isoprene nitrate and peroxy acetyl nitrate (PAN) chemistry. OH concentration increased with relatively lower future isoprene emissions, decreasing methane lifetime by ~7 months (6.6%). Our simulations underline the large uncertainties in future chemistry and climate studies due to biogenic emission patterns and emphasize the problems of using globally averaged climate metrics (such as global radiative forcing) to quantify the atmospheric impact of reactive, heterogeneously distributed substances.

  15. Mechanisms and Functional Significance of Inhibition of Neuronal T-Type Calcium Channels by Isoflurane

    PubMed Central

    Orestes, Peihan; Bojadzic, Damir; Chow, Robert M.; Todorovic, Slobodan M.

    2009-01-01

    Previous data have indicated that T-type calcium channels (low-voltage activated T-channels) are potently inhibited by volatile anesthetics. Although the interactions of T-channels with a number of anesthetics have been described, the mechanisms by which these agents modulate channel activity, and the functional consequences of such interactions, are not well studied. Here, we used patch-clamp recordings to explore the actions of a prototypical volatile anesthetic, isoflurane (Iso), on recombinant human CaV3.1 and CaV3.2 isoforms of T-channels. We also performed behavioral testing of anesthetic endpoints in mice lacking CaV3.2. Iso applied at resting channel states blocked current through both isoforms in a similar manner at clinically relevant concentrations (1 minimum alveolar concentration, MAC). Inhibition was more prominent at depolarized membrane potentials (-65 versus -100 mV) as evidenced by hyperpolarizing shifts in channel availability curves and a 2.5-fold decrease in IC50 values. Iso slowed recovery from inactivation and enhanced deactivation in both CaV3.1 and CaV3.2 in a comparable manner but caused a depolarizing shift in activation curves and greater use-dependent block of CaV3.2 channels. In behavioral tests, CaV3.2 knockout (KO) mice showed significantly decreased MAC in comparison with wild-type (WT) litter mates. KO and WT mice did not differ in loss of righting reflex, but mutant mice displayed a delayed onset of anesthetic induction. We conclude that state-dependent inhibition of T-channel isoforms in the central and peripheral nervous systems may contribute to isoflurane's important clinical effects. PMID:19038845

  16. Lycopene synergistically inhibits LDL oxidation in combination with vitamin E, glabridin, rosmarinic acid, carnosic acid, or garlic.

    PubMed

    Fuhrman, B; Volkova, N; Rosenblat, M; Aviram, M

    2000-01-01

    Several lines of evidence suggest that oxidatively modified low-density lipoprotein (LDL) is atherogenic, and that atherosclerosis can be attenuated by natural antioxidants, which inhibit LDL oxidation. This study was conducted to determine the effect of tomato lycopene alone, or in combination with other natural antioxidants, on LDL oxidation. LDL (100 microg of protein/ml) was incubated with increasing concentrations of lycopene or of tomato oleoresin (lipid extract of tomatoes containing 6% lycopene, 0.1% beta-carotene, 1% vitamin E, and polyphenols), after which it was oxidized by the addition of 5 micromol/liter of CuSO4. Tomato oleoresin exhibited superior capacity to inhibit LDL oxidation in comparison to pure lycopene, by up to five-fold [97% vs. 22% inhibition of thiobarbituric acid reactive substances (TBARS) formation, and 93% vs. 27% inhibition of lipid peroxides formation, respectively]. Because tomato oleoresin also contains, in addition to lycopene, vitamin E, flavonoids, and phenolics, a possible cooperative interaction between lycopene and such natural antioxidants was studied. A combination of lycopene (5 micromol/liter) with vitamin E (alpha-tocopherol) in the concentration range of 1-10 micromol/liter resulted in an inhibition of copper ion-induced LDL oxidation that was significantly greater than the expected additive individual inhibitions. The synergistic antioxidative effect of lycopene with vitamin E was not shared by gamma-to-cotrienol. The polyphenols glabridin (derived from licorice), rosmarinic acid or carnosic acid (derived from rosemary), as well as garlic (which contains a mixture of natural antioxidants) inhibited LDL oxidation in a dose-dependent manner. When lycopene (5 micromol/liter) was added to LDL in combination with glabridin, rosmarinic acid, carnosic acid, or garlic, synergistic antioxidative effects were obtained against LDL oxidation induced either by copper ions or by the radical generator AAPH. Similar interactive

  17. Direct endothelial junction restoration results in significant tumor vascular normalization and metastasis inhibition in mice

    PubMed Central

    Agrawal, Vijayendra; Maharjan, Sony; Kim, Kyeojin; Kim, Nam-Jung; Son, Jimin; Lee, Keunho; Choi, Hyun-Jung; Rho, Seung-Sik; Ahn, Sunjoo; Won, Moo-Ho; Ha, Sang-Jun; Koh, Gou Young; Kim, Young-Myeong; Suh, Young-Ger; Kwon, Young-Guen

    2014-01-01

    Tumor blood vessels are leaky and immature, which causes inadequate blood supply to tumor tissues resulting in hypoxic microenvironment and promotes metastasis. Here we have explored tumor vessel modulating activity of Sac-1004, a recently developed molecule in our lab, which directly potentiates VE-cadherin-mediated endothelial cell junction. Sac-1004 could enhance vascular junction integrity in tumor vessels and thereby inhibit vascular leakage and enhance vascular perfusion. Improved perfusion enabled Sac-1004 to have synergistic anti-tumor effect on cisplatin-mediated apoptosis of tumor cells. Interestingly, characteristics of normalized blood vessels namely reduced hypoxia, improved pericyte coverage and decreased basement membrane thickness were readily observed in tumors treated with Sac-1004. Remarkably, Sac-1004 was also able to inhibit lung and lymph node metastasis in MMTV and B16BL6 tumor models. This was in correlation with a reduction in epithelial-to-mesenchymal transition of tumor cells with considerable diminution in expression of related transcription factors. Moreover, cancer stem cell population dropped substantially in Sac-1004 treated tumor tissues. Taken together, our results showed that direct restoration of vascular junction could be a significant strategy to induce normalization of tumor blood vessels and reduce metastasis. PMID:24811731

  18. Direct endothelial junction restoration results in significant tumor vascular normalization and metastasis inhibition in mice.

    PubMed

    Agrawal, Vijayendra; Maharjan, Sony; Kim, Kyeojin; Kim, Nam-Jung; Son, Jimin; Lee, Keunho; Choi, Hyun-Jung; Rho, Seung-Sik; Ahn, Sunjoo; Won, Moo-Ho; Ha, Sang-Jun; Koh, Gou Young; Kim, Young-Myeong; Suh, Young-Ger; Kwon, Young-Guen

    2014-05-15

    Tumor blood vessels are leaky and immature, which causes inadequate blood supply to tumor tissues resulting in hypoxic microenvironment and promotes metastasis. Here we have explored tumor vessel modulating activity of Sac-1004, a recently developed molecule in our lab, which directly potentiates VE-cadherin-mediated endothelial cell junction. Sac-1004 could enhance vascular junction integrity in tumor vessels and thereby inhibit vascular leakage and enhance vascular perfusion. Improved perfusion enabled Sac-1004 to have synergistic anti-tumor effect on cisplatin-mediated apoptosis of tumor cells. Interestingly, characteristics of normalized blood vessels namely reduced hypoxia, improved pericyte coverage and decreased basement membrane thickness were readily observed in tumors treated with Sac-1004. Remarkably, Sac-1004 was also able to inhibit lung and lymph node metastasis in MMTV and B16BL6 tumor models. This was in correlation with a reduction in epithelial-to-mesenchymal transition of tumor cells with considerable diminution in expression of related transcription factors. Moreover, cancer stem cell population dropped substantially in Sac-1004 treated tumor tissues. Taken together, our results showed that direct restoration of vascular junction could be a significant strategy to induce normalization of tumor blood vessels and reduce metastasis. PMID:24811731

  19. Inhibition of arachidonic acid metabolism and its implication on cell proliferation and tumour-angiogenesis.

    PubMed

    Hyde, C A C; Missailidis, S

    2009-06-01

    Arachidonic acid (AA) and its metabolites have recently generated a heightened interest due to growing evidence of their significant role in cancer biology. Thus, inhibitors of the AA cascade, first and foremost COX inhibitors, which have originally been of interest in the treatment of inflammatory conditions and certain types of cardiovascular disease, are now attracting attention as an arsenal against cancer. An increasing number of investigations support their role in cancer chemoprevention, although the precise molecular mechanisms that link levels of AA, and its metabolites, with cancer progression have still to be elucidated. This article provides an overview of the AA cascade and focuses on the roles of its inhibitors and their implication in cancer treatment. In particular, emphasis is placed on the inhibition of cell proliferation and neo-angiogenesis through inhibition of the enzymes COX-2, 5-LOX and CYP450. Downstream effects of inhibition of AA metabolites are analysed and the molecular mechanisms of action of a selected number of inhibitors of catalytic pathways reviewed. Lastly, the benefits of dietary omega-3 fatty acids and their mechanisms of action leading to reduced cancer risk and impeded cancer cell growth are mentioned. Finally, a proposal is put forward, suggesting a novel and integrated approach in viewing the molecular mechanisms and complex interactions responsible for the involvement of AA metabolites in carcinogenesis and the protective effects of omega-3 fatty acids in inflammation and tumour prevention. PMID:19239926

  20. Rosmarinic acid in Argusia argentea inhibits snake venom-induced hemorrhage.

    PubMed

    Aung, Hnin Thanda; Nikai, Toshiaki; Niwa, Masatake; Takaya, Yoshiaki

    2010-10-01

    A methanolic extract of Argusia (or Messerschmidia or Tournefortia) argentea (Boraginaceae) significantly inhibited hemorrhage induced by crude venom of Trimeresurus flavoviridis. The extract was then separated according to antivenom activity by using silica gel column chromatography and HPLC equipped with an octadecylsilanized silica gel (ODS) column to afford rosmarinic acid (RA) (1) as an active principle. RA (1) significantly inhibited the hemorrhagic effect of crude venoms of T. flavoviridis, Crotalus atrox, Gloydius blomhoffii, Bitis arietans as well as snake venom metalloproteinases, HT-b (C. atrox), bilitoxin 2 (Agkistrodon bilineatus), HF (B. arietans), and Ac1-proteinase (Deinagkistrodon acutus). This is the first report of the antihemorrhage activity of RA (1), and RA (1) greatly contributes to the antihemorrhagic efficiency of A. argentea against crude snake venoms and hemorrhagic toxins.

  1. Salicylic acid induces mitochondrial injury by inhibiting ferrochelatase heme biosynthesis activity.

    PubMed

    Gupta, Vipul; Liu, Shujie; Ando, Hideki; Ishii, Ryohei; Tateno, Shumpei; Kaneko, Yuki; Yugami, Masato; Sakamoto, Satoshi; Yamaguchi, Yuki; Nureki, Osamu; Handa, Hiroshi

    2013-12-01

    Salicylic acid is a classic nonsteroidal anti-inflammatory drug. Although salicylic acid also induces mitochondrial injury, the mechanism of its antimitochondrial activity is not well understood. In this study, by using a one-step affinity purification scheme with salicylic acid-immobilized beads, ferrochelatase (FECH), a homodimeric enzyme involved in heme biosynthesis in mitochondria, was identified as a new molecular target of salicylic acid. Moreover, the cocrystal structure of the FECH-salicylic acid complex was determined. Structural and biochemical studies showed that salicylic acid binds to the dimer interface of FECH in two possible orientations and inhibits its enzymatic activity. Mutational analysis confirmed that Trp301 and Leu311, hydrophobic amino acid residues located at the dimer interface, are directly involved in salicylic acid binding. On a gel filtration column, salicylic acid caused a shift in the elution profile of FECH, indicating that its conformational change is induced by salicylic acid binding. In cultured human cells, salicylic acid treatment or FECH knockdown inhibited heme synthesis, whereas salicylic acid did not exert its inhibitory effect in FECH knockdown cells. Concordantly, salicylic acid treatment or FECH knockdown inhibited heme synthesis in zebrafish embryos. Strikingly, the salicylic acid-induced effect in zebrafish was partially rescued by FECH overexpression. Taken together, these findings illustrate that FECH is responsible for salicylic acid-induced inhibition of heme synthesis, which may contribute to its antimitochondrial and anti-inflammatory function. This study establishes a novel aspect of the complex pharmacological effects of salicylic acid.

  2. Omega 3 but not omega 6 fatty acids inhibit AP-1 activity and cell transformation in JB6 cells

    PubMed Central

    Liu, Guangming; Bibus, Douglas M.; Bode, Ann M.; Ma, Wei-Ya; Holman, Ralph T.; Dong, Zigang

    2001-01-01

    Epidemiological and animal-based investigations have indicated that the development of skin cancer is in part associated with poor dietary practices. Lipid content and subsequently the derived fatty acid composition of the diet are believed to play a major role in the development of tumorigenesis. Omega 3 (ω3) fatty acids, including docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), can effectively reduce the risk of skin cancer whereas omega 6 (ω6) fatty acids such as arachidonic acid (AA) reportedly promote risk. To investigate the effects of fatty acids on tumorigenesis, we performed experiments to examine the effects of the ω3 fatty acids EPA and DHA and of the ω6 fatty acid AA on phorbol 12-tetradecanoate 13-acetate (TPA)-induced or epidermal growth factor (EGF)-induced transcription activator protein 1 (AP-1) transactivation and on the subsequent cellular transformation in a mouse epidermal JB6 cell model. DHA treatment resulted in marked inhibition of TPA- and EGF-induced cell transformation by inhibiting AP-1 transactivation. EPA treatment also inhibited TPA-induced AP-1 transactivation and cell transformation but had no effect on EGF-induced transformation. AA treatment had no effect on either TPA- or EGF-induced AP-1 transactivation or transformation, but did abrogate the inhibitory effects of DHA on TPA- or EGF-induced AP-1 transactivation and cell transformation in a dose-dependent manner. The results of this study demonstrate that the inhibitory effects of ω3 fatty acids on tumorigenesis are more significant for DHA than for EPA and are related to an inhibition of AP-1. Similarly, because AA abrogates the beneficial effects of DHA, the dietary ratio of ω6 to ω3 fatty acids may be a significant factor in mediating tumor development. PMID:11416221

  3. Inhibition of acid sensing ion channel by ligustrazine on angina model in rat

    PubMed Central

    Zhang, Zhi-Gang; Zhang, Xiao-Lan; Wang, Xian-Yue; Luo, Zhu-Rong; Song, Jing-Chun

    2015-01-01

    Ligustrazine, a compound extracted from roots of Ligusticum chuanxiong, is widely used in Chinese traditional medicine to treat cardiac and cerebrovascular diseases and pain, including angina. The mechanism(s) of ligustrazine’s effect to reduce angina is not clear. Angina is mediated by cardiac afferent sensory neurons. These neurons display a large acid-evoked depolarizing sodium current that can initiate action potentials in response to acidification that accompanies myocardial ischemia. Acid-sensing ion channels (ASICs) mediate this current. Here we tested the hypothesis that ligustrazine reduces ischemia-induced cardiac dysfunction and acid-evoked pain by an action to inhibit ASIC-mediated current. The effects of ligustrazine to attenuate ischemia-induced ST-segment depression, T wave changes, and myocardial infarct size in hearts of anesthetized rats were determined. Effects of ligustrazine on currents mediated by ASICs expressed in cultured Chinese hamster ovary cells, and effects of the drug on acid-induced nociceptive behavior and acid-induced currents in isolated dorsal root ganglions cells were measured. Ligustrazine significantly attenuated acid-induced ASIC currents, reduced cardiac ischemia-induced electrical dysfunction and infarct size, and decreased the nociceptive response to injection of acid into the paw of the rat hindlimb. The ASIC channel inhibitor A-317567 similarly reduced electrical dysfunction, infarct size, and nociceptive behavior in the rat. Inhibition of ASICs by ligustrazine may explain at least in part the beneficial effects of the drug that are observed in patients with ischemic heart disease and angina. PMID:26692925

  4. Liver acid sphingomyelinase inhibits growth of metastatic colon cancer.

    PubMed

    Osawa, Yosuke; Suetsugu, Atsushi; Matsushima-Nishiwaki, Rie; Yasuda, Ichiro; Saibara, Toshiji; Moriwaki, Hisataka; Seishima, Mitsuru; Kozawa, Osamu

    2013-02-01

    Acid sphingomyelinase (ASM) regulates the homeostasis of sphingolipids, including ceramides and sphingosine-1-phosphate (S1P). These sphingolipids regulate carcinogenesis and proliferation, survival, and apoptosis of cancer cells. However, the role of ASM in host defense against liver metastasis remains unclear. In this study, the involvement of ASM in liver metastasis of colon cancer was examined using Asm-/- and Asm+/+ mice that were inoculated with SL4 colon cancer cells to produce metastatic liver tumors. Asm-/- mice demonstrated enhanced tumor growth and reduced macrophage accumulation in the tumor, accompanied by decreased numbers of hepatic myofibroblasts (hMFs), which express tissue inhibitor of metalloproteinase 1 (TIMP1), around the tumor margin. Tumor growth was increased by macrophage depletion or by Timp1 deficiency, but was decreased by hepatocyte-specific ASM overexpression, which was associated with increased S1P production. S1P stimulated macrophage migration and TIMP1 expression in hMFs in vitro. These findings indicate that ASM in the liver inhibits tumor growth through cytotoxic macrophage accumulation and TIMP1 production by hMFs in response to S1P. Targeting ASM may represent a new therapeutic strategy for treating liver metastasis of colon cancer.

  5. Inhibition of Human Group IIA-Secreted Phospholipase A2 and THP-1 Monocyte Recruitment by Maslinic Acid.

    PubMed

    Yap, Wei Hsum; Ahmed, Nafees; Lim, Yang Mooi

    2016-10-01

    Maslinic acid is a natural pentacyclic triterpenoid which has anti-inflammatory properties. A recent study showed that secretory phospholipase A2 (sPLA2) may be a potential binding target of maslinic acid. The human group IIA (hGIIA)-sPLA2 is found in human sera and their levels are correlated with severity of inflammation. This study aims to determine whether maslinic acid interacts with hGIIA-sPLA2 and inhibits inflammatory response induced by this enzyme. It is shown that maslinic acid enhanced intrinsic fluorescence of hGIIA-sPLA2 and inhibited its enzyme activity in a concentration-dependent manner. Molecular docking revealed that maslinic acid binds to calcium binding and interfacial phospholipid binding site, suggesting that it inhibit access of catalytic calcium ion for enzymatic reaction and block binding of the enzyme to membrane phospholipid. The hGIIA-sPLA2 enzyme is also responsible in mediating monocyte recruitment and differentiation. Results showed that maslinic acid inhibit hGIIA-sPLA2-induced THP-1 cell differentiation and migration, and the effect observed is specific to hGIIA-sPLA2 as cells treated with maslinic acid alone did not significantly affect the number of adherent and migrated cells. Considering that hGIIA-sPLA2 enzyme is known to hydrolyze glyceroacylphospholipids present in lipoproteins and cell membranes, maslinic acid may bind and inhibit hGIIA-sPLA2 enzymatic activity, thereby reduces the release of fatty acids and lysophospholipids which stimulates monocyte migration and differentiation. This study is the first to report on the molecular interaction between maslinic acid and inflammatory target hGIIA-sPLA2 as well as its effect towards hGIIA-sPLA2-induced THP-1 monocyte adhesive and migratory capabilities, an important immune-inflammation process in atherosclerosis.

  6. Cellobionic acid inhibition of cellobiohydrolase I and cellobiose dehydrogenase

    Technology Transfer Automated Retrieval System (TEKTRAN)

    End-product inhibition by cellobiose and glucose is a rate-limiting factor in cellulose hydrolysis by cellulases. While cellobiose and glucose inhibition have been extensively investigated, cellobionate inhibition has been minimally studied despite the discovery that accessory proteins such as cello...

  7. Fish oil constituent docosahexa-enoic acid selectively inhibits growth of human papillomavirus immortalized keratinocytes.

    PubMed

    Chen, D; Auborn, K

    1999-02-01

    The omega-3-fatty acids inhibit proliferation of breast cancer cells whereas omega-6-fatty acids stimulate growth. In this study, we examined effects of these fatty acids on human pre-cancerous cells. Cervical keratinocytes, immortalized with the oncogenic human papillomavirus (HPV) type 16, were treated with linoleic acid, an omega-6-fatty acid, and the omega-3-fatty acids, eicosapentaenoic and docosahexaenoic acids. Using both cell counts and bromodeoxyuridine incorporation, docosahexaenoic acid inhibited growth of these cells to a greater extent than eicosapenta-enoic acid. Linoleic acid had no effect. The effect of docosahexaenoic acid was dose dependent and caused growth arrest. Docosahexaenoic acid inhibited growth of HPV16 immortalized foreskin keratinocytes and laryngeal keratinocytes grown from explants of benign tumors caused by papillomavirus, but had no effect on normal foreskin and laryngeal keratinocytes. Docosahexaenoic acid inhibited growth in the presence of estradiol, a growth stimulator for these cells. Indomethacin, a cyclooxygenase inhibitor like docosahexaenoic acid, had only minimal effect on growth. Alpha-tocopherol, a peroxidation inhibitor, abrogated effects of docosahexaenoic acid implying that inhibitory effects were via lipid peroxidation. PMID:10069461

  8. Corosolic acid inhibits the proliferation of glomerular mesangial cells and protects against diabetic renal damage

    PubMed Central

    Li, Xiao-Qiang; Tian, Wen; Liu, Xiao-Xiao; Zhang, Kai; Huo, Jun-Cheng; Liu, Wen-Juan; Li, Ping; Xiao, Xiong; Zhao, Ming-Gao; Cao, Wei

    2016-01-01

    Diabetic nephropathy (DN) is one of the major complications of diabetes mellitus (DM). This study aimed to explore the effects of corosolic acid (CA) on the renal damage of DM and the mechanisms behind these effects. The renoprotective effect of CA was investigated in type 1 diabetic rats and db/db mice. The kidneys and glomerular mesangial cells (GMCs) were used to study the proliferation of GMCs by immunostaining and MTT assay. Further immunoblotting, siRNA, qPCR analysis, and detecting of NADPH oxidase activity and reactive oxygen species (ROS) generation were performed to explore relevant molecular mechanisms. In CA-treated diabetic animals, diabetes-induced albuminuria, increased serum creatinine and blood urea nitrogen were significantly attenuated, and glomerular hypertrophy, mesangial expansion and fibrosis were ameliorated. Furthermore, CA significantly inhibited proliferation of GMCs and phosphorylation of ERK1/2 and p38 MAPK in both diabetic animals and high glucose (HG)-induced GMCs. CA also normalized Δψm and inhibited HG-induced NADPH oxidase activity, ROS generation and NOX4, NOX2, p22phox and p47phox expression. More importantly, CA inhibited GMC proliferation mediated by NADPH/ERK1/2 and p38 MAPK signaling pathways. These findings suggest that CA exert the protective effect on DN by anti-proliferation resulted from inhibition of p38 MAPK- and NADPH-mediated inactivation of ERK1/2. PMID:27229751

  9. Wall teichoic acid protects Staphylococcus aureus from inhibition by Congo red and other dyes

    PubMed Central

    Suzuki, Takashi; Campbell, Jennifer; Kim, Younghoon; Swoboda, Jonathan G.; Mylonakis, Eleftherios; Walker, Suzanne; Gilmore, Michael S.

    2012-01-01

    Objectives Polyanionic polymers, including lipoteichoic acid and wall teichoic acid, are important determinants of the charged character of the staphylococcal cell wall. This study was designed to investigate the extent to which teichoic acid contributes to protection from anionic azo dyes and to identify barriers to drug penetration for development of new antibiotics for multidrug-resistant Staphylococcus aureus infection. Methods We studied antimicrobial activity of azo dyes against S. aureus strains with or without inhibition of teichoic acid in vitro and in vivo. Results We observed that inhibition of wall teichoic acid expression resulted in an ∼1000-fold increase in susceptibility to azo dyes such as Congo red, reducing its MIC from >1024 to <4 mg/L. Sensitization occurred when the first step in the wall teichoic acid pathway, catalysed by TarO, was inhibited either by mutation or by chemical inhibition. In contrast, genetic blockade of lipoteichoic acid biosynthesis did not confer Congo red susceptibility. Based on this finding, combination therapy was tested using the highly synergistic combination of Congo red plus tunicamycin at sub-MIC concentrations (to inhibit wall teichoic acid biosynthesis). The combination rescued Caenorhabditis elegans from a lethal challenge of S. aureus. Conclusions Our studies show that wall teichoic acid confers protection to S. aureus from anionic azo dyes and related compounds, and its inhibition raises the prospect of development of new combination therapies based on this inhibition. PMID:22615298

  10. Caffeic acid phenethyl ester inhibits liver fibrosis in rats

    PubMed Central

    Li, Mei; Wang, Xiu-Fang; Shi, Juan-Juan; Li, Ya-Ping; Yang, Ning; Zhai, Song; Dang, Shuang-Suo

    2015-01-01

    AIM: To investigate the hepatoprotective effects and antioxidant activity of caffeic acid phenethyl ester (CAPE) in rats with liver fibrosis. METHODS: A total of 75 male Sprague-Dawley rats were randomly assigned to seven experimental groups: a normal group (n = 10), a vehicle group (n = 10), a model group (n = 15), a vitamin E group (n = 10), and three CAPE groups (CAPE 3, 6 and 12 mg/kg, n = 10, respectively). Liver fibrosis was induced in rats by injecting CCl4 subcutaneously, feeding with high fat forage, and administering 30% alcohol orally for 10 wk. Concurrently, CAPE (3, 6 and 12 mg/kg) was intraperitoneally administered daily for 10 wk. After that, serum total bilirubin (TBil), aminotransferase (ALT) and aspartate aminotransferase (AST) levels were measured to assess hepatotoxicity. To investigate antioxidant activity of CAPE, malondialdehyde (MDA), glutathione (GSH) levels, catalase (CAT) and superoxide dismutase (SOD) activities in liver tissue were determined. Moreover, the effect of CAPE on α-smooth muscle actin (α-SMA), a characteristic hallmark of activated hepatic stellate cells (HSCs), and NF-E2-related factor 2 (Nrf2), a key transcription factor for antioxidant systems, was investigated by immunohistochemistry. RESULTS: Compared to the model group, intraperitoneal administration of CAPE decreased TBil, ALT, and AST levels in liver fibrosis rats (P < 0.05), while serum TBil was decreased by CAPE in a dose-dependent manner. In addition, the liver hydroxyproline contents in both the 6 and 12 mg/kg CAPE groups were markedly lower than that in the model group (P < 0.05 and P < 0.001, respectively). CAPE markedly decreased MDA levels and, in turn, increased GSH levels, as well as CAT and SOD activities in liver fibrosis rats compared to the model group (P < 0.05). Moreover, CAPE effectively inhibited α-SMA expression while increasing Nrf2 expression compared to the model group (P < 0.01). CONCLUSION: The protective effects of CAPE against liver

  11. 3,5-Dihydroxybenzoic acid, a specific agonist for hydroxycarboxylic acid 1, inhibits lipolysis in adipocytes.

    PubMed

    Liu, Changlu; Kuei, Chester; Zhu, Jessica; Yu, Jingxue; Zhang, Li; Shih, Amy; Mirzadegan, Taraneh; Shelton, Jonathan; Sutton, Steven; Connelly, Margery A; Lee, Grace; Carruthers, Nicholas; Wu, Jiejun; Lovenberg, Timothy W

    2012-06-01

    Niacin raises high-density lipoprotein and lowers low-density lipoprotein through the activation of the β-hydroxybutyrate receptor hydroxycarboxylic acid 2 (HCA2) (aka GPR109a) but with an unwanted side effect of cutaneous flushing caused by vascular dilation because of the stimulation of HCA2 receptors in Langerhans cells in skin. HCA1 (aka GPR81), predominantly expressed in adipocytes, was recently identified as a receptor for lactate. Activation of HCA1 in adipocytes by lactate results in the inhibition of lipolysis, suggesting that agonists for HCA1 may be useful for the treatment of dyslipidemia. Lactate is a metabolite of glucose, suggesting that HCA1 may also be involved in the regulation of glucose metabolism. The low potency of lactate to activate HCA1, coupled with its fast turnover rate in vivo, render it an inadequate tool for studying the biological role of lactate/HCA1 in vivo. In this article, we demonstrate the identification of 3-hydroxybenzoic acid (3-HBA) as an agonist for both HCA2 and HCA1, whereas 3,5-dihydroxybenzoic acid (3,5-DHBA) is a specific agonist for only HCA1 (EC(50) ∼150 μM). 3,5-DHBA inhibits lipolysis in wild-type mouse adipocytes but not in HCA1-deficient adipocytes. Therefore, 3,5-DHBA is a useful tool for the in vivo study of HCA1 function and offers a base for further HCA1 agonist design. Because 3-HBA and 3,5-DHBA are polyphenolic acids found in many natural products, such as fruits, berries, and coffee, it is intriguing to speculate that other heretofore undiscovered natural substances may have therapeutic benefits.

  12. Tachykinin inhibition of acid-induced gastric hyperaemia in the rat.

    PubMed Central

    Heinemann, A.; Jocic, M.; Herzeg, G.; Holzer, P.

    1996-01-01

    1. Primary afferent neurones releasing the vasodilator, calcitonin gene-related peptide, mediate the gastric hyperaemic response to acid back-diffusion. The tachykinins neurokinin A (NKA) and substance P (SP) are located in the same neurones and are co-released with calcitonin gene-related peptide. In this study we investigated the effect and possible role of tachykinins in the acid-evoked gastric vasodilatation in urethane-anaesthetized rats. 2. Gastric acid back-diffusion, induced by perfusing the stomach with 15% ethanol in the presence of 0.05 M HCl, increased gastric mucosal blood flow by 60-90%, as determined by the hydrogen clearance technique. NKA and SP (0.14-3.78 nmol min-1 kg-1, infused intra-aortically) inhibited the gastric mucosal hyperaemic response to acid back-diffusion in a dose-dependent manner, an effect that was accompanied by aggravation of ethanol/acid-induced macroscopic haemorrhagic lesions. 3. The inhibitory effect of NKA (1.26 nmol min-1 kg-1) on the acid-induced gastric mucosal vasodilatation was prevented by the tachykinin NK2 receptor antagonists, MEN 10,627 (200 nmol kg-1) but left unaltered by the NK1 receptor antagonist, SR 140,333 (300 nmol kg-1) and the mast-cell stabilizer, ketotifen (4.6 mumol kg-1). 4. Under basal conditions, with 0.05 M HCl being perfused through the stomach, NKA (1.26 nmol min-1 kg-1) reduced gastric mucosal blood flow by about 25%, an effect that was abolished by SR 140,333 but not MEN 10,627 or ketotifen. 5. SR 140,333, MEN 10,627 or ketotifen had no significant effect on basal gastric mucosal blood flow nor did they modify the gastric mucosal hyperaemic reaction to acid back-diffusion. 6. The effect of NKA (1.26 nmol min-1 kg-1) in causing vasoconstriction and inhibiting the vasodilator response to acid back-diffusion was also seen when blood flow in the left gastric artery was measured with the ultrasonic transit time shift technique. 7. Arginine vasopressin (AVP, 0.1 nmol min-1 kg-1) induced gastric

  13. Inhibition of ultraviolet-induced carcinogenesis by all-trans retinoic acid

    SciTech Connect

    Epstein, J.H.; Grekin, D.A.

    1981-03-01

    The effects of all-trans retinoic acid (RA) in 0.05%, 0.025% and 0.005% concentrations on ultraviolet (UV) induced carcinogenesis was investigated in the skin of Uscd strain hairless mice. A carcinogenic amount of UV energy was delivered over the 12-mo period of the study. The 0.025% and 0.005% RA solutions did not alter the development of cutaneous cancers. However, the 0.05% RA concentration significantly inhibited the tumor formation in this study.

  14. Inhibition of natural killer cell activity by eicosapentaenoic acid in vivo and in vitro

    SciTech Connect

    Yamashita, N.; Sugiyama, E.; Hamazaki, T.; Yano, S.

    1988-01-15

    To examine the effects of in vivo eicosapentaenoic acid (EPA) on natural killer (NK) cell activity, C3H/He mice each received a single intraperitoneal bolus of an emulsion of trieicosapentaenoyl-glycerol (EPA-TG). Spleen cells were tested for NK activity using /sup 51/Chromium-release assays against YAC-1 target cells. Forty eight hours after injection, NK activity was inhibited in a dose-dependent manner. EPA-TG emulsion also inhibited the NK activity of NK-enriched effector cells. Decreased cytotoxicity was first noted 24 hr after injection; it resumed the baseline by 7 days. The addition of EPA-TG emulsion to a cytotoxicity assay system resulted in moderate depression of NK activity. These results demonstrate that EPA has significant immunomodulatory effects on NK activity.

  15. Corosolic Acid Inhibits Hepatocellular Carcinoma Cell Migration by Targeting the VEGFR2/Src/FAK Pathway

    PubMed Central

    Ku, Chung-Yu; Wang, Ying-Ren; Lin, Hsuan-Yuan; Lu, Shao-Chun; Lin, Jung-Yaw

    2015-01-01

    Inhibition of VEGFR2 activity has been proposed as an important strategy for the clinical treatment of hepatocellular carcinoma (HCC). In this study, we identified corosolic acid (CA), which exists in the root of Actinidia chinensis, as having a significant anti-cancer effect on HCC cells. We found that CA inhibits VEGFR2 kinase activity by directly interacting with the ATP binding pocket. CA down-regulates the VEGFR2/Src/FAK/cdc42 axis, subsequently decreasing F-actin formation and migratory activity in vitro. In an in vivo model, CA exhibited an effective dose (5 mg/kg/day) on tumor growth. We further demonstrate that CA has a synergistic effect with sorafenib within a wide range of concentrations. In conclusion, this research elucidates the effects and molecular mechanism for CA on HCC cells and suggests that CA could be a therapeutic or adjuvant strategy for patients with aggressive HCC. PMID:25978354

  16. Inhibition of N-nitrosamine carcinogenesis and aflatoxin DNA damage by ellagic acid

    SciTech Connect

    Mandal-Chaudhuri, S.

    1988-01-01

    The effect of ellagic acid (EA), on the tumorigenicity of N-nitrosobenzylmethylamine (NBMA) in the rat esophagus was investigated. Groups of 30 male F-344 rats were fed a semipurified diet containing EA for 27 weeks. N-nitrosobenzylmethylamine was administered subcutaneously, once a week for 18 weeks. Ellagic acid produced a significant inhibition in the average number of esophageal tumors at both 20 weeks and 27 weeks. To investigate the mechanism(s) of this inhibition, EA was tested for its effect on the metabolism, DNA-binding and DNA-adduct formation of NBMA in cultured explants of rat esophagus. Explants were incubated in medium containing EA at concentrations of 10, 50, and 100 {mu}M for 16 hours, followed by the addition of 1{mu}M ({sup 3}H)NBMA and EA for 12 hours. Explant DNA was isolated by phenol extraction and hydroxylapatite chromatography, and benzaldehyde formation was determined by h.p.l.c. analysis of the culture medium. Finally, EA was examined for its ability to inhibit DNA damage induced by aflatoxin B{sub 1} (AFB{sub 1}) in cultured explants of rat trachea and esophagus, and human tracheobronchus.

  17. Simultaneous inhibition of carbon and nitrogen mineralization in a forest soil by simulated acid precipitation

    SciTech Connect

    Klein, T.M.; Novick, N.J.; Kreitinger, J.P.; Alexander, M.

    1984-06-01

    One method to simulate the long-term exposure of soil to acid rain involves the addition of single doses of concentrated acid. The inhibition of carbon mineralization accompanied by a stimulation of nitrogen mineralization may result from this severe, unnatural treatment. The present study was designed to determine whether the inhibition of carbon mineralization and the accompanying enhanced nitrogen mineralization would occur when soils are treated with more dilute acid for long periods of time, as takes place in nature.

  18. Inhibition of de novo Palmitate Synthesis by Fatty Acid Synthase Induces Apoptosis in Tumor Cells by Remodeling Cell Membranes, Inhibiting Signaling Pathways, and Reprogramming Gene Expression

    PubMed Central

    Ventura, Richard; Mordec, Kasia; Waszczuk, Joanna; Wang, Zhaoti; Lai, Julie; Fridlib, Marina; Buckley, Douglas; Kemble, George; Heuer, Timothy S.

    2015-01-01

    Inhibition of de novo palmitate synthesis via fatty acid synthase (FASN) inhibition provides an unproven approach to cancer therapy with a strong biological rationale. FASN expression increases with tumor progression and associates with chemoresistance, tumor metastasis, and diminished patient survival in numerous tumor types. TVB-3166, an orally-available, reversible, potent, and selective FASN inhibitor induces apoptosis, inhibits anchorage-independent cell growth under lipid-rich conditions, and inhibits in-vivo xenograft tumor growth. Dose-dependent effects are observed between 20–200 nM TVB-3166, which agrees with the IC50 in biochemical FASN and cellular palmitate synthesis assays. Mechanistic studies show that FASN inhibition disrupts lipid raft architecture, inhibits biological pathways such as lipid biosynthesis, PI3K–AKT–mTOR and β-catenin signal transduction, and inhibits expression of oncogenic effectors such as c-Myc; effects that are tumor-cell specific. Our results demonstrate that FASN inhibition has anti-tumor activities in biologically diverse preclinical tumor models and provide mechanistic and pharmacologic evidence that FASN inhibition presents a promising therapeutic strategy for treating a variety of cancers, including those expressing mutant K-Ras, ErbB2, c-Met, and PTEN. The reported findings inform ongoing studies to link mechanisms of action with defined tumor types and advance the discovery of biomarkers supporting development of FASN inhibitors as cancer therapeutics. Research in context Fatty acid synthase (FASN) is a vital enzyme in tumor cell biology; the over-expression of FASN is associated with diminished patient prognosis and resistance to many cancer therapies. Our data demonstrate that selective and potent FASN inhibition with TVB-3166 leads to selective death of tumor cells, without significant effect on normal cells, and inhibits in vivo xenograft tumor growth at well-tolerated doses. Candidate biomarkers for

  19. [Cyclooxygenase inhibitors in some dietary vegetables inhibit platelet aggregation function induced by arachidonic acid].

    PubMed

    Wang, Xin-Hua; Shao, Dong-Hua; Liang, Guo-Wei; Zhang, Ru; Xin, Qin; Zhang, Tao; Cao, Qing-Yun

    2011-10-01

    The study was purposed to investigate whether the cyclooxygenase inhibitors from some dietary vegetables can inhibit platelet aggregation function by the arachidonic acid (AA). The vegetable juice was mixed with platelet rich plasma (PRP), and asprin was used as positive control. The maximum ratio of platelet aggregation induced by AA was measured on the aggregometer; heme and cyclooxygenase-1 (COX(1)) or cyclooxygenase-2 (COX(2)) were added to test tubes containing COX reaction buffer, the mixture was vortex-mixed and exposed to aspirin or vegetable juice, followed by addition of AA and then hydrochloric acid (1 mol/L) was added to stop the COX reaction, followed by chemical reduction with stannous chloride solution. The concentration of COX inhibitors was detected by the enzyme immunoassay kit; vegetable juice (aspirin as positive control) was mixed with whole blood, which was followed by the addition of AA, and then the reaction was stopped by adding indomethacin, centrifuged, then the supernatant was collected, and the plasma thromboxane B(2) (TXB(2)) was measured by radioimmunoassay. The results showed that spinach juice, garlic bolt juice, blanched garlic leave juice and Chinese leek juice could inhibit by 80% human platelet aggregation induced by AA. 4 kinds of vegetables were all found a certain amount of cyclooxygenase inhibitors, which COX(1) and COX(2) inhibitor concentrations of spinach were higher than that of aspirin; 4 vegetable juice could significantly reduce the human plasma concentrations of TXB(2) induced by AA (p < 0.05). It is concluded that 4 kinds of raw vegetables containing cyclooxygenase inhibitors inhibit the production of TXA(2) and thus hinder platelet aggregation. Raw spinach, garlic bolt, blanched garlic and chinese leek inhibit significantly AA-induced human platelet aggregation in vitro. 4 kinds of vegetables may have a good potential perspective of anti-platelet aggregation therapy or prevention of thrombosis.

  20. Oleanolic acid modulates multiple intracellular targets to inhibit colorectal cancer growth.

    PubMed

    Li, Li; Wei, Lihui; Shen, Aling; Chu, Jianfeng; Lin, Jiumao; Peng, Jun

    2015-12-01

    Due to drug resistance and unacceptable cytotoxicity of most currently-used cancer chemotherapies, naturally occurring products have gained attention in the field of anticancer treatment. Oleanolic acid (OA) is a natural pentacyclic triterpenoic acid and a principal active compound in many medicinal herbs that have long been used to clinically treat various types of human malignancies. Using a colorectal cancer (CRC) mouse xenograft model and the cell line HT-29, we evaluated the effect of OA on tumor growth in vivo and in vitro, and investigated the underlying molecular mechanisms in the present study. We found that OA significantly inhibited tumor growth in volume and weight in CRC xenograft mice. In addition, OA treatment led to the induction of apoptosis and inhibition of cell proliferation. OA significantly reduced the expression of Bcl-2, Cyclin D1 and CKD4, whereas Bax and p21 expression was profoundly increased after OA treatment. Furthermore, OA significantly suppressed the activation of Akt, p70S6K and MAPK signalings, but promoted p53 pathway activation. Collectively, findings from this study suggest that OA possesses a broad range of anticancer effects via modulation of multiple intracellular targets. PMID:26459864

  1. High Molecular Weight Hyaluronic Acid Inhibits Fibrosis of Endometrium

    PubMed Central

    Zhu, Yi; Hu, Jianguo; Yu, Tinghe; Ren, Yan; Hu, Lina

    2016-01-01

    Background Elevated fibrosis has been found in patients with intrauterine adhesion, which indicates that fibrotic factors may play a critical role in formation of intrauterine adhesion. The aim of this study was to identify the effect of hyaluronic acid (HA) at high and low molecular weight on fibrosis of the endometrium in a mouse model of Asherman’s syndrome. Material/Methods Endometrial fibrosis in a mouse model of Asherman’s syndrome was confirmed. Then HA at high and low molecular weight was injected into the uterine cavity. Endometrial fibrosis was compared among the control group, LMW-HA, and HMW-HA group. The extent of endometrial fibrosis was calculated using Masson stain. The fibrosis markers (TGFβ1, CTGF, collagen I, and collagen III) in endometrial tissue were detected using immunohistochemistry and Western blotting. Results The ratio of the area with endometrial fibrosis to total endometrial area in the HMW-HA group was significantly decreased compared to the control group (P<0.05). The expression of fibrosis markers (TGFβ1, CTGF, collagen I, and collagen III) in the endometrium was attenuated in the HMW-HA group compared to the control group, but the LMW-HA group had no similar effect. Conclusions Hyaluronic acid at high molecular weight may attenuate the degree of endometrial fibrosis after endometrial damage, which may contribute to preventing formation of intrauterine adhesions. PMID:27670361

  2. Sphingoid bases inhibit acid-induced demineralization of hydroxyapatite.

    PubMed

    Valentijn-Benz, Marianne; van 't Hof, Wim; Bikker, Floris J; Nazmi, Kamran; Brand, Henk S; Sotres, Javier; Lindh, Liselott; Arnebrant, Thomas; Veerman, Enno C I

    2015-01-01

    Calcium hydroxyapatite (HAp), the main constituent of dental enamel, is inherently susceptible to the etching and dissolving action of acids, resulting in tooth decay such as dental caries and dental erosion. Since the prevalence of erosive wear is gradually increasing, there is urgent need for agents that protect the enamel against erosive attacks. In the present study we studied in vitro the anti-erosive effects of a number of sphingolipids and sphingoid bases, which form the backbone of sphingolipids. Pretreatment of HAp discs with sphingosine, phytosphingosine (PHS), PHS phosphate and sphinganine significantly protected these against acid-induced demineralization by 80 ± 17%, 78 ± 17%, 78 ± 7% and 81 ± 8%, respectively (p < 0.001). On the other hand, sphingomyelin, acetyl PHS, octanoyl PHS and stearoyl PHS had no anti-erosive effects. Atomic force measurement revealed that HAp discs treated with PHS were almost completely and homogeneously covered by patches of PHS. This suggests that PHS and other sphingoid bases form layers on the surface of HAp, which act as diffusion barriers against H(+) ions. In principle, these anti-erosive properties make PHS and related sphingosines promising and attractive candidates as ingredients in oral care products.

  3. Aminomethylphosphonic acid inhibits growth and metastasis of human prostate cancer in an orthotopic xenograft mouse model

    PubMed Central

    Parajuli, Keshab Raj; Zhang, Qiuyang; Liu, Sen; You, Zongbing

    2016-01-01

    Aminomethylphosphonic acid (AMPA) has been shown to inhibit prostate cancer cell growth in vitro. The purpose of the present study was to determine if AMPA could inhibit growth and metastasis of prostate cancer in vivo. Human prostate cancer PC-3-LacZ-luciferase cells were implanted into the ventral lateral lobes of the prostate in 39 athymic Nu/Nu nude male mice. Seven days later, mice were randomized into the control group (n = 14, treated intraperitoneally with phosphate buffered saline), low dose group (n = 10, treated intraperitoneally with AMPA at 400 mg/kg body weight/day), and high dose group (n = 15, treated intraperitoneally with AMPA at 800 mg/kg body weight/day). Tumor growth and metastasis were examined every 4-7 days by bioluminescence imaging of live mice. We found that AMPA treatment significantly inhibited growth and metastasis of orthotopic xenograft prostate tumors and prolonged the survival time of the mice. AMPA treatment decreased expression of BIRC2 and activated caspase 3, leading to increased apoptosis in the prostate tumors. AMPA treatment decreased expression of cyclin D1. AMPA treatment also reduced angiogenesis in the prostate tumors. Taken together, these results demonstrate that AMPA can inhibit prostate cancer growth and metastasis, suggesting that AMPA may be developed into a therapeutic agent for the treatment of prostate cancer. PMID:26840261

  4. Dual effects of acetylsalicylic acid on ERK signaling and Mitf transcription lead to inhibition of melanogenesis.

    PubMed

    Nishio, Takashi; Usami, Mai; Awaji, Mizuki; Shinohara, Sumire; Sato, Kazuomi

    2016-01-01

    Acetylsalicylic acid (ASA) is widely used as an analgesic/antipyretic drug. It exhibits a wide range of biological effects, including preventative effects against heart attack and stroke, and the induction of apoptosis in various cancer cells. We previously found that ASA inhibits melanogenesis in B16 melanoma cells. However, the mechanisms of how ASA down-regulates melanin synthesis remain unclear. Here, we investigated the effect of ASA on melanogenic pathways, such as extracellular signal-regulated kinase (ERK) and microphthalmia-associated transcription factor (Mitf) transcription. ASA significantly inhibited melanin synthesis in a dose-dependent manner without oxidative stress and cell death. Semi-quantitative reverse transcription-polymerase chain reaction analysis showed that the inhibitory effect of ASA might be due to the inhibition of Mitf gene transcription. Interestingly, ASA also induced ERK phosphorylation. Additionally, treatment with PD98059, a specific ERK phosphorylation inhibitor, abolished the anti-melanogenic effect of ASA. These results suggest that the depigmenting effect of ASA results from down-regulation of Mitf, which is induced by both the induction of ERK phosphorylation and the inhibition of Mitf transcription.

  5. Dual effects of acetylsalicylic acid on ERK signaling and Mitf transcription lead to inhibition of melanogenesis.

    PubMed

    Nishio, Takashi; Usami, Mai; Awaji, Mizuki; Shinohara, Sumire; Sato, Kazuomi

    2016-01-01

    Acetylsalicylic acid (ASA) is widely used as an analgesic/antipyretic drug. It exhibits a wide range of biological effects, including preventative effects against heart attack and stroke, and the induction of apoptosis in various cancer cells. We previously found that ASA inhibits melanogenesis in B16 melanoma cells. However, the mechanisms of how ASA down-regulates melanin synthesis remain unclear. Here, we investigated the effect of ASA on melanogenic pathways, such as extracellular signal-regulated kinase (ERK) and microphthalmia-associated transcription factor (Mitf) transcription. ASA significantly inhibited melanin synthesis in a dose-dependent manner without oxidative stress and cell death. Semi-quantitative reverse transcription-polymerase chain reaction analysis showed that the inhibitory effect of ASA might be due to the inhibition of Mitf gene transcription. Interestingly, ASA also induced ERK phosphorylation. Additionally, treatment with PD98059, a specific ERK phosphorylation inhibitor, abolished the anti-melanogenic effect of ASA. These results suggest that the depigmenting effect of ASA results from down-regulation of Mitf, which is induced by both the induction of ERK phosphorylation and the inhibition of Mitf transcription. PMID:26699907

  6. Inhibition of fatty acid synthase by amentoflavone reduces coxsackievirus B3 replication.

    PubMed

    Wilsky, Steffi; Sobotta, Katharina; Wiesener, Nadine; Pilas, Johanna; Althof, Nadine; Munder, Thomas; Wutzler, Peter; Henke, Andreas

    2012-02-01

    Coxsackievirus B3 (CVB3) is a human pathogen that causes acute and chronic infections, but an antiviral drug to treat these diseases has not yet been developed for clinical use. Several intracellular pathways are altered to assist viral transcription, RNA replication, and progeny release. Among these, fatty acid synthase (FAS) expression is increased. In order to test the potential of FAS inhibition as an anti-CVB3 strategy, several experiments were performed, including studies on the correlation of CVB3 replication and FAS expression in human Raji cells and an analysis of the time and dose dependence of the antiviral effect of FAS inhibition due to treatment with amentoflavone. The results demonstrate that CVB3 infection induces an up-regulation of FAS expression already at 1 h postinfection (p.i.). Incubation with increasing concentrations of amentoflavone inhibited CVB3 replication significantly up to 8 h p.i. In addition, suppression of p38 MAP kinase activity by treatment with SB239063 decreased FAS expression as well as viral replication. These data provide evidence that FAS inhibition via amentoflavone administration might present a target for anti-CVB3 therapy. PMID:22075919

  7. Inhibition of nocturnal acidity is important but not essential for duodenal ulcer healing.

    PubMed Central

    Bianchi Porro, G; Parente, F; Sangaletti, O

    1990-01-01

    We have determined the relative importance of day and night time gastric acid inhibition for duodenal ulcer healing by comparing the anti-ulcer efficacy of a single morning with that of a single bedtime dose of ranitidine. One hundred and thirty patients with active duodenal ulcer were randomly assigned to a double-blind therapy with ranitidine 300 mg at 8 am or the same dose at 10 pm for up to eight weeks. The antisecretory effects of these regimens were also assessed by 24 h intragastric pH monitoring in 18 of these patients. At four weeks ulcers had healed in 41/61 (67%) of patients taking the morning dose and in 47/63 (75%) of those receiving the nocturnal dose (95% CI for the difference -0.09 +0.25; p ns). At eight weeks, the corresponding healing rates were 82% and 85.5%, respectively (95% CI for the difference -0.11 +0.17; p ns). Both treatments were significantly superior to placebo in raising 24 h intragastric pH, although the effects of the morning dose were of shorter duration than those of the nocturnal dose. These findings suggest that suppression of nocturnal acidity is important but not essential to promote healing of duodenal ulcers; a prolonged period of acid inhibition during the day (as obtained with a single large morning dose of H2-blockers) may be equally effective. PMID:2186980

  8. Mealtime versus nighttime acid inhibition. A clinical pharmacological study with ranitidine.

    PubMed

    Savarino, V; Mela, G S; Zentilin, P; Vigneri, S; Cutela, P; Mele, R; Di Mario, F

    1992-09-01

    This study was carried out in order to compare the effects of mealtime and bedtime regimens of ranitidine on gastric acidity. Fifteen duodenal ulcer patients in clinical remission were randomized to receive in single-blind fashion either placebo, ranitidine 300 mg at night (2200 hr) or ranitidine 150 mg three times a day given before each of the three daily meals (1800, 0800 and 1200 hr). Over 24 hr, the two active treatments produced a significantly greater acid inhibition than placebo, while the single daily regimen was superior to the three times a day regimen of ranitidine in terms of both rise in pH values (P less than 0.001) and duration of action expressed as time spent above 3.0 pH units (P less than 0.05). The analysis of these two parameters during fractioned periods of the circadian cycle showed that the three divided doses of ranitidine were more effective during the daytime (P less than 0.01) and the evening (P less than 0.001), whereas the bedtime dose of ranitidine was superior during the night (P less than 0.0001). Thus a short-lasting antisecretory action, which is, however, capable of fully controlling the high acidity of postprandial periods, might be the key to understanding the results of several recent clinical trials in which the suppression of daytime gastric acidity has been shown to promote similar or even faster duodenal ulcer healing rates than the suppression of nocturnal acidity.

  9. Mechanism of specific inhibition of phototropism by phenylacetic acid in corn seedling

    SciTech Connect

    Vierstra, R.D.; Poff, K.L.

    1981-05-01

    Using geotropism as a control for phototropism, compounds similar to phenylacetic acid that phototreact with flavins and/or have auxin-like activity were examined for their ability to specifically inhibit phototropism in corn seedlings using geotropism as a control. Results using indole-3-acetic acid, napthalene-1-acetic acid, naphthalene-2-acetic acid, phenylacetic acid, and ..beta..-phenylpyruvic acid suggest that such compounds will specifically inhibit phototropism primarily because of their photoreactivity with flavins and not their auxin activity. In addition, the in vivo concentration of phenylacetic acid required to induce specificity was well below that required to stimulate coleoptile growth. Estimates of the percentage of photoreceptor pigment inactivated by phenylacetic acid (>10%) suggest that phenylacetic acid could be used to photoaffinity label the flavoprotein involved in corn seedling phototropism.

  10. Nucleic acid-based inhibition of flavivirus infections.

    PubMed

    Stein, David A; Shi, Pei-Yong

    2008-01-01

    The genus Flavivirus in the family Flaviviridae consists of many arthropod-transmitted human pathogens, including dengue, yellow fever, Japanese encephalitis, West Nile, St. Louis encephalitis, Murray Valley encephalitis, and tick-borne encephalitis viruses. Treatment options against flaviviral disease are extremely limited, with no effective drugs yet commercially available. Recent advances in virology, synthetic organic chemistry, and the discovery of RNA interference (RNAi), have provided the basis for advances in the development of antisense-based approaches to address flaviviral infections. Oligomers of various antisense structural types, targeted to different locations in the flaviviral RNA genome, have now been used to successfully suppress viral gene expression and thereby inhibit flavivirus replication. Double-stranded RNA, containing viral sequence and designed to induce the endogenous cellular machinery of RNAi, has also been shown capable of potently interfering with flavivirus production and transmission. These studies provide insights into flaviviral molecular biology and the basis for the development of novel therapeutic approaches. The goal of this review is to summarize the findings of many of the significant reports that have appeared on the topic of antisense-mediated strategies for the development of antiviral therapy for flaviviruses.

  11. Inhibition of mild steel corrosion by sodium dodecyl benzene sulfonate and sodium oleate in acidic solutions

    SciTech Connect

    Luo, H.; Han, K.N.; Guan, Y.C.

    1998-08-01

    Inhibition of mild steel corrosion by sodium dodecyl benzene sulfonate (C{sub 12}H{sub 25}C{sub 6}H{sub 4}SO{sub 3}Na [SDBS]) and sodium oleate (CH{sub 3}[CH{sub 2}]{sub 7}CH{double_bond}CH[CH{sub 2}]{sub 7}COONa) in acidic solutions was investigated using a potentiostat, a lock-in amplifier, a contact angle goniometer, A fourier transform infrared (FTIR) spectrometer, and an ultraviolet (UV)/visible spectrophotometer. In the presence of the organic inhibitors, the corrosion rate was reduced significantly, Anionic SDBS was adsorbed on the positively charged mild steel surface through the electrostatic attraction. However, for sodium oleate, the soluble oleic acid (CH{sub 3}[CH{sub 2}]{sub 7}CH{double_bond}CH[CH]{sub 7}COOH) chemisorbed on the steel surface at the first stage. Then, insoluble colloid adsorbed on the chemisorbed surface through van der Waals forces.

  12. Enhanced fatty acid accumulation in Isochrysis galbana by inhibition of the mitochondrial alternative oxidase pathway under nitrogen deprivation.

    PubMed

    Zhang, Litao; Liu, Jianguo

    2016-07-01

    The purpose of this study was to clarify the interrelation between the mitochondrial alternative oxidase (AOX) pathway and fatty acid accumulation in marine microalga Isochrysis galbana. Under normal conditions, the activity of the AOX pathway was maintained at a low level in I. galbana. Compared with the normal condition, nitrogen deprivation significantly increased the AOX pathway activity and fatty acid accumulation. Under nitrogen deprivation, the inhibition of the AOX pathway by salicylhydroxamic acid caused the accumulation of reducing equivalents and the over-reduction of chloroplasts in I. galbana cells, leading to a decrease in the photosynthetic O2 evolution rate. The over-production of reducing equivalents due to the inhibition of the AOX pathway under nitrogen deprivation further enhanced the accumulation of fatty acids in I. galbana cells.

  13. Lonicera hypoglauca inhibits xanthine oxidase and reduces serum uric acid in mice.

    PubMed

    Chien, Shih-Chang; Yang, Chen-Wei; Tseng, Yen-Hsueh; Tsay, Hsin-Sheng; Kuo, Yueh-Hsiung; Wang, Sheng-Yang

    2009-03-01

    Xanthine oxidase (XOD) catalyzes the oxidation of hypoxanthine to xanthine and then to uric acid, and is a key enzyme in the pathogenesis of hyperuricemia. The ability of extracts of Lonicera hypoglauca (Caprifoliaceae) to inhibit XOD was investigated in this study. An ethanol extract (LH-crude) of the leaves of L. hypoglauca and its derived EtOAc soluble sub-fractions (LH-EA) significantly inhibited XOD activity, with IC50 values for LH-crude and LH-EA of 48.8 and 35.2 microg/mL. Moreover, LH-EA reduced serum urate levels IN VIVO in a potassium oxonate-induced hyperuricemic mouse model, by 70.1% and 93.7% of the hyperuricemic untreated group at doses of 300 and 500 mg/kg of LH-EA, respectively. Finally, we used bioactivity-guided fractionation to isolate a new bisflavonoid, loniceraflavone, which showed significant inhibition of XOD (IC50=0.85 microg/mL). These results suggest that L. hypoglauca and its extracts may have a considerable potential for development as an anti-hyperuricemia agent for clinical application.

  14. Kinetic study of oxalic acid inhibition on enzymatic browning.

    PubMed

    Son, S M; Moon, K D; Lee, C Y

    2000-06-01

    Oxalic acid has a strong antibrowning activity. The inhibitory pattern on catechol-PPO model system appeared to be competitive, with a K(i) value of 2.0 mM. When the PPO was incubated with oxalic acid, the activity was not recovered via dialysis, but the inactivated enzyme partially recovered its activity when cupric ion was added. Comparing the relative antibrowning effectiveness of oxalic acid with other common antibrowning agents, oxalic acid with I(50) value of 1.1 mM is as effective as kojic acid and more potent than cysteine and glutathione.

  15. Piperazic acid derivatives inhibit Gli1 in Hedgehog signaling pathway.

    PubMed

    Khatra, Harleen; Kundu, Jayanta; Khan, Pragya Paramita; Duttagupta, Indranil; Pattanayak, Sankha; Sinha, Surajit

    2016-09-15

    Piperazic acid, a non-proteinogenic amino acid, found in complex secondary metabolites and peptide natural substances, has shown down regulation of Gli1 expression in Hedgehog signaling pathway in cell based assays. Further structure activity relationship study indicated that amide derivatives of piperazic acid are more potent than piperazic acid itself, with little to no toxicity. However, other cellular components involved in the pathway were not affected. To the best of our knowledge, this is the first report on the inhibitory property of piperazic acid in this pathway. Hence, this molecule could serve as a useful tool for studying Hedgehog signaling. PMID:27528433

  16. Alpha lipoic acid inhibits proliferation and epithelial mesenchymal transition of thyroid cancer cells.

    PubMed

    Jeon, Min Ji; Kim, Won Gu; Lim, Seonhee; Choi, Hyun-Jeung; Sim, Soyoung; Kim, Tae Yong; Shong, Young Kee; Kim, Won Bae

    2016-01-01

    The naturally occurring short-chain fatty acid, α-lipoic acid (ALA) is a powerful antioxidant which is clinically used for treatment of diabetic neuropathy. Recent studies suggested the possibility of ALA as a potential anti-cancer agent, because it could activate adenosine monophosphate activated protein kinase (AMPK) and inhibit transforming growth factor-β (TGFβ) pathway. In this study, we evaluate the effects of ALA on thyroid cancer cell proliferation, migration and invasion. We performed in vitro cell proliferation analysis using BCPAP, HTH-83, CAL-62 and FTC-133 cells. ALA suppressed thyroid cancer cell proliferation through activation of AMPK and subsequent down-regulation of mammalian target of rapamycin (mTOR)-S6 signaling pathway. Low-dose ALA, which had minimal effects on cell proliferation, also decreased cell migration and invasion of BCPAP, CAL-62 and HTH-83 cells. ALA inhibited epithelial mesenchymal transition (EMT) evidently by increase of E-cadherin and decreases of activated β-catenin, vimentin, snail, and twist in these cells. ALA suppressed TGFβ production and inhibited induction of p-Smad2 and twist by TGFβ1 or TGFβ2. These findings indicate that ALA reduces cancer cell migration and invasion through suppression of TGFβ production and inhibition of TGFβ signaling pathways in thyroid cancer cells. ALA also significantly suppressed tumor growth in mouse xenograft model using BCPAP and FTC-133 cells. This is the first study to show anti-cancer effect of ALA on thyroid cancer cells. ALA could be a potential therapeutic agent for treatment of advanced thyroid cancer, possibly as an adjuvant therapy with other systemic therapeutic agents.

  17. Development of poly(aspartic acid-co-malic acid) composites for calcium carbonate and sulphate scale inhibition.

    PubMed

    Mithil Kumar, N; Gupta, Sanjay Kumar; Jagadeesh, Dani; Kanny, K; Bux, F

    2015-01-01

    Polyaspartic acid (PSI) is suitable for the inhibition of inorganic scale deposition. To enhance its scale inhibition efficiency, PSI was modified by reacting aspartic acid with malic acid (MA) using thermal polycondensation polymerization. This reaction resulted in poly(aspartic acid-co-malic acid) (PSI-co-MA) dual polymer. The structural, chemical and thermal properties of the dual polymers were analysed by using scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry and gel permeation chromatography. The effectiveness of six different molar ratios of PSI-co-MA dual polymer for calcium carbonate and calcium sulphate scale inhibition at laboratory scale batch experiments was evaluated with synthetic brine solution at selected doses of polymer at 65-70°C by the static scale test method. The performance of PSI-co-MA dual polymer for the inhibition of calcium carbonate and calcium sulphate precipitation was compared with that of a PSI single polymer. The PSI-co-MA exhibited excellent ability to control inorganic minerals, with approximately 85.36% calcium carbonate inhibition and 100% calcium sulphate inhibition at a level of 10 mg/L PSI-co-MA, respectively. Therefore, it may be reasonably concluded that PSI-co-MA is a highly effective scale inhibitor for cooling water treatment applications.

  18. Bile acid inhibition of taurocholate uptake by rat hepatocytes: role of OH groups

    SciTech Connect

    Bellentani, S.; Hardison, W.G.M.; Marchegiano, P.; Zanasi, G.; Manenti, F.

    1987-03-01

    To define further the structural specificity of the taurocholate uptake site, the authors studied the ability of a variety of taurine-conjugated bile acids with differing hydroxyl substituents on the sterol moiety to inhibit (/sup 14/C) taurocholate uptake. Rat hepatocytes isolated by collagenase perfusion were incubated in a tris (hydroxymethyl) aminomethane-phosphate buffer containing (/sup 14/C)taurocholate in the presence or absence of inhibitor bile acid. Stronger inhibitors were studied at a fixed concentration of 5 ..mu..M, weaker ones at 25 ..mu..M. Initial uptake velocity was measured. Uptake velocity could then be related to taurocholate concentration and a V/sub max/ and K/sub m/ could be determined by applying a nonlinear least squares fit to the data obtained with or without inhibitor. The kinetic parameters allowed the determination of the type of inhibition and of inhibition constants (K/sub i/) of the various test bile acids. The data indicate that bile acids containing a 6- or 7-OH group exhibit competitive inhibition, whereas bile acids with no 6- or 7-OH group exhibit noncompetitive inhibition. Of the compounds exhibiting competitive inhibition, K/sub i/ varied with the number of hydroxyl groups on the sterol moiety. They conclude that the presence of absence of a 6- or 7-OH group dictates the mechanism of inhibition; the number of hydroxyl substituents determines the potency of competitive inhibition.

  19. Myristoleic acid inhibits osteoclast formation and bone resorption by suppressing the RANKL activation of Src and Pyk2.

    PubMed

    Kwon, Jun-Oh; Jin, Won Jong; Kim, Bongjun; Kim, Hong-Hee; Lee, Zang Hee

    2015-12-01

    Cytoskeletal changes in osteoclasts such as formation of actin ring is required for bone-resorbing activity. The tyrosine kinase Src is a key player in massive cytoskeletal change of osteoclasts, thereby in bone destruction. In order for Src to be activated, trafficking to the inner plasma membrane via myristoylation is of importance. A previous study reported that myristoleic acid derived from myristic acid, inhibited N-myristoyl-transferase, an essential enzyme for myristoylation process. This prompted us to investigate whether myristoleic acid could affect osteoclastogenesis. Indeed, we observed that myristoleic acid inhibited RANKL-induced osteoclast formation in vitro, especially, at later stages of differentiation. Myristoleic acid attenuated the tyrosine phosphorylation of c-Src and Pyk2, which associates with Src, by RANKL. When myristoleic acid was co-administered with soluble RANKL into mice, RANKL-induced bone loss was substantially prevented. Bone dissection clearly revealed that the number of multinucleated osteoclasts was significantly diminished by myristoleic acid. On the other hand, myristoleic acid treatment had little or no influence on early osteoclast differentiation markers, such as c-Fos and NFATc1, and proteins related to cytoskeletal rearrangement, including DC-STAMP, integrin αv and integrin β3 in vitro. Taken together, our data suggest that myristoleic acid is capable of blocking the formation of large multinucleated osteoclasts and bone resorption likely through suppressing activation of Src and Pyk2.

  20. Inhibition of Listeria monocytogenes and Salmonella by combinations of oriental mustard, malic acid, and EDTA.

    PubMed

    Olaimat, Amin N; Holley, Richard A

    2014-04-01

    The antimicrobial activities of oriental mustard extract alone or combined with malic acid and EDTA were investigated against Salmonella spp. or Listeria monocytogenes at different temperatures. Five strain Salmonella or L. monocytogenes cocktails were separately inoculated in Brain Heart Infusion broth containing 0.5% (w/v) aqueous oriental mustard extract and incubated at 4 °C to 21 °C for 21 d. For inhibitor combination tests, Salmonella Typhimurium 02:8423 and L. monocytogenes 2-243 were individually inoculated in Mueller Hinton broth containing the mustard extract with either or both 0.2% (w/v) malic acid and 0.2% (w/v) EDTA and incubated at 10 °C or 21 °C for 10 to 14 d. Mustard extract inhibited growth of the L. monocytogenes cocktail at 4 °C up to 21 d (2.3 log10 CFU/mL inhibition) or at 10 °C for 7 d (2.4 log10 CFU/mL inhibition). Salmonella spp. viability was slightly, but significantly reduced by mustard extract at 4 °C by 21 d. Although hydrolysis of sinigrin in mustard extract by both pathogens was 2 to 6 times higher at 21 °C than at 4 °C to 10 °C, mustard was not inhibitory at 21 °C, perhaps because of the instability of its hydrolysis product (allyl isothiocyanate). At 21 °C, additive inhibitory effects of mustard extract with EDTA or malic acid led to undetectable levels of S. Typhimurium and L. monocytogenes by 7 d and 10 d, respectively. At 10 °C, S. Typhimurium was similarly susceptible, but combinations of antimicrobials were not more inhibitory to L. monocytogenes than the individual agents.

  1. [Inhibition of glutamine synthetase activity by biologically active derivatives of glutamic acid].

    PubMed

    Firsova, N A; Selivanova, K M; Alekseeva, L V; Evstigneeva, Z G

    1986-05-01

    The inhibition of activity of glutamine synthetase from Chlorella and porcine brain by 4-hydroxy-D-4-fluoro-D,L- and 4-amino-D,L-glutamic acids diastereoisomers was studied. Each compound was shown to exert the same inhibiting effect on glutamine synthetase from both sources. In case of threo-4-hydroxy-D-glutamic acid the inhibition of the Chlorella enzyme was of a competitive and of a completely mixed type. The enzyme inhibition by 4-fluoro-D, L-glutamic acids seemed to be of a completely non-competitive type. The Ki values for all inhibition reactions were determined. A comparison of biochemical parameters and biological activity revealed that the most effective inhibitors of the enzyme exert a most potent antitumour and antiviral action.

  2. Eicosapentaenoic acid inhibits glucose-induced membrane cholesterol crystalline domain formation through a potent antioxidant mechanism.

    PubMed

    Mason, R Preston; Jacob, Robert F

    2015-02-01

    Lipid oxidation leads to endothelial dysfunction, inflammation, and foam cell formation during atherogenesis. Glucose also contributes to lipid oxidation and promotes pathologic changes in membrane structural organization, including the development of cholesterol crystalline domains. In this study, we tested the comparative effects of eicosapentaenoic acid (EPA), an omega-3 fatty acid indicated for the treatment of very high triglyceride (TG) levels, and other TG-lowering agents (fenofibrate, niacin, and gemfibrozil) on lipid oxidation in human low-density lipoprotein (LDL) as well as membrane lipid vesicles prepared in the presence of glucose (200 mg/dL). We also examined the antioxidant effects of EPA in combination with atorvastatin o-hydroxy (active) metabolite (ATM). Glucose-induced changes in membrane structural organization were measured using small angle x-ray scattering approaches and correlated with changes in lipid hydroperoxide (LOOH) levels. EPA was found to inhibit LDL oxidation in a dose-dependent manner (1.0-10.0 µM) and was distinguished from the other TG-lowering agents, which had no significant effect as compared to vehicle treatment alone. Similar effects were observed in membrane lipid vesicles exposed to hyperglycemic conditions. The antioxidant activity of EPA, as observed in glucose-treated vesicles, was significantly enhanced in combination with ATM. Glucose treatment produced highly-ordered, membrane-restricted, cholesterol crystalline domains, which correlated with increased LOOH levels. Of the agents tested in this study, only EPA inhibited glucose-induced cholesterol domain formation. These data demonstrate that EPA, at pharmacologic levels, inhibits hyperglycemia-induced changes in membrane lipid structural organization through a potent antioxidant mechanism associated with its distinct, physicochemical interactions with the membrane bilayer. PMID:25449996

  3. Mixture additives inhibit the dermal permeation of the fatty acid, ricinoleic acid.

    PubMed

    Baynes, R E; Riviere, J E

    2004-02-28

    Ricinoleic acid (RA) like many of the ingredients in machine cutting fluids and other industrial formulations are potential dermal irritants, yet very little is known about its permeability in skin. 3H-ricinoleic acid mixtures were formulated with three commonly used cutting fluid additives; namely, triazine (TRI), linear alkylbenzene sulfonate (LAS), and triethanolamine (TEA) and topically applied to inert silastic membranes and porcine skin in vitro as aqueous mineral oil (MO) or polyethylene glycol (PEG) mixtures. These additives significantly decreased ricinoleic acid partitioning from the formulation into the stratum corneum (SC) in PEG-based mixtures. Except for LAS, all other additives produced a more basic formulation (pH = 9.3-10.3). In silastic membranes and porcine skin, individual additives or combination of additives significantly reduced ricinoleic permeability. This trend in ricinoleic acid disposition in both membranes suggests that the mixture interaction is more physicochemical in nature and probably not related to the chemical-induced changes in the biological membrane as may be assumed with topical exposures to potentially irritant formulations.

  4. HDAC Inhibition Modulates Cardiac PPARs and Fatty Acid Metabolism in Diabetic Cardiomyopathy.

    PubMed

    Lee, Ting-I; Kao, Yu-Hsun; Tsai, Wen-Chin; Chung, Cheng-Chih; Chen, Yao-Chang; Chen, Yi-Jen

    2016-01-01

    Peroxisome proliferator-activated receptors (PPARs) regulate cardiac glucose and lipid homeostasis. Histone deacetylase (HDAC) inhibitor has anti-inflammatory effects which may play a key role in modulating PPARs and fatty acid metabolism. The aim of this study was to investigate whether HDAC inhibitor, MPT0E014, can modulate myocardial PPARs, inflammation, and fatty acid metabolism in diabetes mellitus (DM) cardiomyopathy. Electrocardiography, echocardiography, and western blotting were used to evaluate the electrophysiological activity, cardiac structure, fatty acid metabolism, inflammation, and PPAR isoform expressions in the control and streptozotocin-nicotinamide-induced DM rats with or without MPT0E014. Compared to control, DM and MPT0E014-treated DM rats had elevated blood glucose levels and lower body weights. However, MPT0E014-treated DM and control rats had smaller left ventricular end-diastolic diameter and shorter QT interval than DM rats. The control and MPT0E014-treated DM rats had greater cardiac PPAR-α and PPAR-δ protein expressions, but less cardiac PPAR-γ than DM rats. Moreover, control and MPT0E014-treated DM rats had lower concentrations of 5' adenosine monophosphate-activated protein kinase 2α, PPAR-γ coactivator 1α, phosphorylated acetyl CoA carboxylase, cluster of differentiation 36, diacylglycerol acyltransferase 1 (DGAT1), DGAT2, tumor necrosis factor-α, and interleukin-6 protein than DM rats. HDAC inhibition significantly attenuated DM cardiomyopathy through modulation of cardiac PPARS, fatty acid metabolism, and proinflammatory cytokines. PMID:27446205

  5. Inhibition of apical sodium-dependent bile acid transporter as a novel treatment for diabetes.

    PubMed

    Chen, Lihong; Yao, Xiaozhou; Young, Andrew; McNulty, Judi; Anderson, Don; Liu, Yaping; Nystrom, Christopher; Croom, Dallas; Ross, Sean; Collins, Jon; Rajpal, Deepak; Hamlet, Kimberly; Smith, Chari; Gedulin, Bronislava

    2012-01-01

    Bile acids are recognized as metabolic modulators. The present study was aimed at evaluating the effects of a potent Asbt inhibitor (264W94), which blocks intestinal absorption of bile acids, on glucose homeostasis in Zucker Diabetic Fatty (ZDF) rats. Oral administration of 264W94 for two wk increased fecal bile acid concentrations and elevated non-fasting plasma total Glp-1. Treatment of 264W94 significantly decreased HbA1c and glucose, and prevented the drop of insulin levels typical of ZDF rats in a dose-dependent manner. An oral glucose tolerance test revealed up to two-fold increase in plasma total Glp-1 and three-fold increase in insulin in 264W94 treated ZDF rats at doses sufficient to achieve glycemic control. Tissue mRNA analysis indicated a decrease in farnesoid X receptor (Fxr) activation in small intestines and the liver but co-administration of a Fxr agonist (GW4064) did not attenuate 264W94 induced glucose lowering effects. In summary, our results demonstrate that inhibition of Asbt increases bile acids in the distal intestine, promotes Glp-1 release and may offer a new therapeutic strategy for type 2 diabetes mellitus.

  6. Inhibition of DNA methylation by caffeic acid and chlorogenic acid, two common catechol-containing coffee polyphenols.

    PubMed

    Lee, Won Jun; Zhu, Bao Ting

    2006-02-01

    We studied the modulating effects of caffeic acid and chlorogenic acid (two common coffee polyphenols) on the in vitro methylation of synthetic DNA substrates and also on the methylation status of the promoter region of a representative gene in two human cancer cells lines. Under conditions that were suitable for the in vitro enzymatic methylation of DNA and dietary catechols, we found that the presence of caffeic acid or chlorogenic acid inhibited in a concentration-dependent manner the DNA methylation catalyzed by prokaryotic M.SssI DNA methyltransferase (DNMT) and human DNMT1. The IC50 values of caffeic acid and chlorogenic acid were 3.0 and 0.75 microM, respectively, for the inhibition of M.SssI DNMT-mediated DNA methylation, and were 2.3 and 0.9 microM, respectively, for the inhibition of human DNMT1-mediated DNA methylation. The maximal in vitro inhibition of DNA methylation was approximately 80% when the highest concentration (20 microM) of caffeic acid or chlorogenic acid was tested. Kinetic analyses showed that DNA methylation catalyzed by M.SssI DNMT or human DNMT1 followed the Michaelis-Menten curve patterns. The presence of caffeic acid or chlorogenic acid inhibited DNA methylation predominantly through a non-competitive mechanism, and this inhibition was largely due to the increased formation of S-adenosyl-L-homocysteine (SAH, a potent inhibitor of DNA methylation), resulting from the catechol-O-methyltransferase (COMT)-mediated O-methylation of these dietary catechols. Using cultured MCF-7 and MAD-MB-231 human breast cancer cells, we also demonstrated that treatment of these cells with caffeic acid or chlorogenic acid partially inhibited the methylation of the promoter region of the RARbeta gene. The findings of our present study provide a general mechanistic basis for the notion that a variety of dietary catechols can function as inhibitors of DNA methylation through increased formation of SAH during the COMT-mediated O-methylation of these dietary

  7. Inhibition of Na+-Taurocholate Co-transporting Polypeptide-mediated Bile Acid Transport by Cholestatic Sulfated Progesterone Metabolites*

    PubMed Central

    Abu-Hayyeh, Shadi; Martinez-Becerra, Pablo; Sheikh Abdul Kadir, Siti H.; Selden, Clare; Romero, Marta R.; Rees, Myrddin; Marschall, Hanns-Ulrich; Marin, Jose J. G.; Williamson, Catherine

    2010-01-01

    Sulfated progesterone metabolite (P4-S) levels are raised in normal pregnancy and elevated further in intrahepatic cholestasis of pregnancy (ICP), a bile acid-liver disorder of pregnancy. ICP can be complicated by preterm labor and intrauterine death. The impact of P4-S on bile acid uptake was studied using two experimental models of hepatic uptake of bile acids, namely cultured primary human hepatocytes (PHH) and Na+-taurocholate co-transporting polypeptide (NTCP)-expressing Xenopus laevis oocytes. Two P4-S compounds, allopregnanolone-sulfate (PM4-S) and epiallopregnanolone-sulfate (PM5-S), reduced [3H]taurocholate (TC) uptake in a dose-dependent manner in PHH, with both Na+-dependent and -independent bile acid uptake systems significantly inhibited. PM5-S-mediated inhibition of TC uptake could be reversed by increasing the TC concentration against a fixed PM5-S dose indicating competitive inhibition. Experiments using NTCP-expressing Xenopus oocytes confirmed that PM4-S/PM5-S are capable of competitively inhibiting NTCP-mediated uptake of [3H]TC. Total serum PM4-S + PM5-S levels were measured in non-pregnant and third trimester pregnant women using liquid chromatography-electrospray tandem mass spectrometry and were increased in pregnant women, at levels capable of inhibiting TC uptake. In conclusion, pregnancy levels of P4-S can inhibit Na+-dependent and -independent influx of taurocholate in PHH and cause competitive inhibition of NTCP-mediated uptake of taurocholate in Xenopus oocytes. PMID:20177056

  8. Gut Microbiota Conversion of Dietary Ellagic Acid into Bioactive Phytoceutical Urolithin A Inhibits Heme Peroxidases

    PubMed Central

    Saha, Piu; Yeoh, Beng San; Singh, Rajbir; Chandrasekar, Bhargavi; Vemula, Praveen Kumar; Haribabu, Bodduluri; Vijay-Kumar, Matam; Jala, Venkatakrishna R.

    2016-01-01

    Numerous studies signify that diets rich in phytochemicals offer many beneficial functions specifically during pathologic conditions, yet their effects are often not uniform due to inter-individual variation. The host indigenous gut microbiota and their modifications of dietary phytochemicals have emerged as factors that greatly influence the efficacy of phytoceutical-based intervention. Here, we investigated the biological activities of one such active microbial metabolite, Urolithin A (UA or 3,8-dihydroxybenzo[c]chromen-6-one), which is derived from the ellagic acid (EA). Our study demonstrates that UA potently inhibits heme peroxidases i.e. myeloperoxidase (MPO) and lactoperoxidase (LPO) when compared to the parent compound EA. In addition, chrome azurol S (CAS) assay suggests that EA, but not UA, is capable of binding to Fe3+, due to its catechol-like structure, although its modest heme peroxidase inhibitory activity is abrogated upon Fe3+-binding. Interestingly, UA-mediated MPO and LPO inhibition can be prevented by innate immune protein human NGAL or its murine ortholog lipocalin 2 (Lcn2), implying the complex nature of host innate immunity-microbiota interactions. Spectral analysis indicates that UA inhibits heme peroxidase-catalyzed reaction by reverting the peroxidase back to its inactive native state. In support of these in vitro results, UA significantly reduced phorbol myristate acetate (PMA)-induced superoxide generation in neutrophils, however, EA failed to block the superoxide generation. Treatment with UA significantly reduced PMA-induced mouse ear edema and MPO activity compared to EA treated mice. Collectively, our results demonstrate that microbiota-mediated conversion of EA to UA is advantageous to both host and microbiota i.e. UA-mediated inhibition of pro-oxidant enzymes reduce tissue inflammation, mitigate non-specific killing of gut bacteria, and abrogate iron-binding property of EA, thus providing a competitive edge to the microbiota in

  9. Gut Microbiota Conversion of Dietary Ellagic Acid into Bioactive Phytoceutical Urolithin A Inhibits Heme Peroxidases.

    PubMed

    Saha, Piu; Yeoh, Beng San; Singh, Rajbir; Chandrasekar, Bhargavi; Vemula, Praveen Kumar; Haribabu, Bodduluri; Vijay-Kumar, Matam; Jala, Venkatakrishna R

    2016-01-01

    Numerous studies signify that diets rich in phytochemicals offer many beneficial functions specifically during pathologic conditions, yet their effects are often not uniform due to inter-individual variation. The host indigenous gut microbiota and their modifications of dietary phytochemicals have emerged as factors that greatly influence the efficacy of phytoceutical-based intervention. Here, we investigated the biological activities of one such active microbial metabolite, Urolithin A (UA or 3,8-dihydroxybenzo[c]chromen-6-one), which is derived from the ellagic acid (EA). Our study demonstrates that UA potently inhibits heme peroxidases i.e. myeloperoxidase (MPO) and lactoperoxidase (LPO) when compared to the parent compound EA. In addition, chrome azurol S (CAS) assay suggests that EA, but not UA, is capable of binding to Fe3+, due to its catechol-like structure, although its modest heme peroxidase inhibitory activity is abrogated upon Fe3+-binding. Interestingly, UA-mediated MPO and LPO inhibition can be prevented by innate immune protein human NGAL or its murine ortholog lipocalin 2 (Lcn2), implying the complex nature of host innate immunity-microbiota interactions. Spectral analysis indicates that UA inhibits heme peroxidase-catalyzed reaction by reverting the peroxidase back to its inactive native state. In support of these in vitro results, UA significantly reduced phorbol myristate acetate (PMA)-induced superoxide generation in neutrophils, however, EA failed to block the superoxide generation. Treatment with UA significantly reduced PMA-induced mouse ear edema and MPO activity compared to EA treated mice. Collectively, our results demonstrate that microbiota-mediated conversion of EA to UA is advantageous to both host and microbiota i.e. UA-mediated inhibition of pro-oxidant enzymes reduce tissue inflammation, mitigate non-specific killing of gut bacteria, and abrogate iron-binding property of EA, thus providing a competitive edge to the microbiota in

  10. Gut Microbiota Conversion of Dietary Ellagic Acid into Bioactive Phytoceutical Urolithin A Inhibits Heme Peroxidases.

    PubMed

    Saha, Piu; Yeoh, Beng San; Singh, Rajbir; Chandrasekar, Bhargavi; Vemula, Praveen Kumar; Haribabu, Bodduluri; Vijay-Kumar, Matam; Jala, Venkatakrishna R

    2016-01-01

    Numerous studies signify that diets rich in phytochemicals offer many beneficial functions specifically during pathologic conditions, yet their effects are often not uniform due to inter-individual variation. The host indigenous gut microbiota and their modifications of dietary phytochemicals have emerged as factors that greatly influence the efficacy of phytoceutical-based intervention. Here, we investigated the biological activities of one such active microbial metabolite, Urolithin A (UA or 3,8-dihydroxybenzo[c]chromen-6-one), which is derived from the ellagic acid (EA). Our study demonstrates that UA potently inhibits heme peroxidases i.e. myeloperoxidase (MPO) and lactoperoxidase (LPO) when compared to the parent compound EA. In addition, chrome azurol S (CAS) assay suggests that EA, but not UA, is capable of binding to Fe3+, due to its catechol-like structure, although its modest heme peroxidase inhibitory activity is abrogated upon Fe3+-binding. Interestingly, UA-mediated MPO and LPO inhibition can be prevented by innate immune protein human NGAL or its murine ortholog lipocalin 2 (Lcn2), implying the complex nature of host innate immunity-microbiota interactions. Spectral analysis indicates that UA inhibits heme peroxidase-catalyzed reaction by reverting the peroxidase back to its inactive native state. In support of these in vitro results, UA significantly reduced phorbol myristate acetate (PMA)-induced superoxide generation in neutrophils, however, EA failed to block the superoxide generation. Treatment with UA significantly reduced PMA-induced mouse ear edema and MPO activity compared to EA treated mice. Collectively, our results demonstrate that microbiota-mediated conversion of EA to UA is advantageous to both host and microbiota i.e. UA-mediated inhibition of pro-oxidant enzymes reduce tissue inflammation, mitigate non-specific killing of gut bacteria, and abrogate iron-binding property of EA, thus providing a competitive edge to the microbiota in

  11. Inhibition of Pig Phosphoenolpyruvate Carboxykinase Isoenzymes by 3-Mercaptopicolinic Acid and Novel Inhibitors.

    PubMed

    Hidalgo, Jorge; Latorre, Pedro; Carrodeguas, José Alberto; Velázquez-Campoy, Adrián; Sancho, Javier; López-Buesa, Pascual

    2016-01-01

    There exist two isoforms of cytosolic phosphoenolpyruvate carboxykinase (PEPCK-C) in pig populations that differ in a single amino acid (Met139Leu). The isoenzymes have different kinetic properties, affecting more strongly the Km and Vmax of nucleotides. They are associated to different phenotypes modifying traits of considerable economic interest. In this work we use inhibitors of phosphoenolpyruvate carboxykinase activity to search for further differences between these isoenzymes. On the one hand we have used the well-known inhibitor 3-mercaptopicolinic acid. Its inhibition patterns were the same for both isoenzymes: a three-fold decrease of the Ki values for GTP in 139Met and 139Leu (273 and 873 μM, respectively). On the other hand, through screening of a chemical library we have found two novel compounds with inhibitory effects of a similar magnitude to that of 3-mercaptopicolinic acid but with less solubility and specificity. One of these novel compounds, (N'1-({5-[1-methyl-5-(trifluoromethyl)-1H-pyrazol-3-yl]-2-thienyl}methylidene)-2,4-dichlorobenzene-1-carbohydrazide), exhibited significantly different inhibitory effects on either isoenzyme: it enhanced threefold the apparent Km value for GTP in 139Met, whereas in 139Leu, it reduced it from 99 to 69 μM. The finding of those significant differences in the binding of GTP reinforces the hypothesis that the Met139Leu substitution affects strongly the nucleotide binding site of PEPCK-C.

  12. Inhibition of Pig Phosphoenolpyruvate Carboxykinase Isoenzymes by 3-Mercaptopicolinic Acid and Novel Inhibitors

    PubMed Central

    Hidalgo, Jorge; Latorre, Pedro; Carrodeguas, José Alberto; Velázquez-Campoy, Adrián; Sancho, Javier; López-Buesa, Pascual

    2016-01-01

    There exist two isoforms of cytosolic phosphoenolpyruvate carboxykinase (PEPCK-C) in pig populations that differ in a single amino acid (Met139Leu). The isoenzymes have different kinetic properties, affecting more strongly the Km and Vmax of nucleotides. They are associated to different phenotypes modifying traits of considerable economic interest. In this work we use inhibitors of phosphoenolpyruvate carboxykinase activity to search for further differences between these isoenzymes. On the one hand we have used the well-known inhibitor 3-mercaptopicolinic acid. Its inhibition patterns were the same for both isoenzymes: a three-fold decrease of the Ki values for GTP in 139Met and 139Leu (273 and 873 μM, respectively). On the other hand, through screening of a chemical library we have found two novel compounds with inhibitory effects of a similar magnitude to that of 3-mercaptopicolinic acid but with less solubility and specificity. One of these novel compounds, (N'1-({5-[1-methyl-5-(trifluoromethyl)-1H-pyrazol-3-yl]-2-thienyl}methylidene)-2,4-dichlorobenzene-1-carbohydrazide), exhibited significantly different inhibitory effects on either isoenzyme: it enhanced threefold the apparent Km value for GTP in 139Met, whereas in 139Leu, it reduced it from 99 to 69 μM. The finding of those significant differences in the binding of GTP reinforces the hypothesis that the Met139Leu substitution affects strongly the nucleotide binding site of PEPCK-C. PMID:27391465

  13. Inhibition of Pig Phosphoenolpyruvate Carboxykinase Isoenzymes by 3-Mercaptopicolinic Acid and Novel Inhibitors.

    PubMed

    Hidalgo, Jorge; Latorre, Pedro; Carrodeguas, José Alberto; Velázquez-Campoy, Adrián; Sancho, Javier; López-Buesa, Pascual

    2016-01-01

    There exist two isoforms of cytosolic phosphoenolpyruvate carboxykinase (PEPCK-C) in pig populations that differ in a single amino acid (Met139Leu). The isoenzymes have different kinetic properties, affecting more strongly the Km and Vmax of nucleotides. They are associated to different phenotypes modifying traits of considerable economic interest. In this work we use inhibitors of phosphoenolpyruvate carboxykinase activity to search for further differences between these isoenzymes. On the one hand we have used the well-known inhibitor 3-mercaptopicolinic acid. Its inhibition patterns were the same for both isoenzymes: a three-fold decrease of the Ki values for GTP in 139Met and 139Leu (273 and 873 μM, respectively). On the other hand, through screening of a chemical library we have found two novel compounds with inhibitory effects of a similar magnitude to that of 3-mercaptopicolinic acid but with less solubility and specificity. One of these novel compounds, (N'1-({5-[1-methyl-5-(trifluoromethyl)-1H-pyrazol-3-yl]-2-thienyl}methylidene)-2,4-dichlorobenzene-1-carbohydrazide), exhibited significantly different inhibitory effects on either isoenzyme: it enhanced threefold the apparent Km value for GTP in 139Met, whereas in 139Leu, it reduced it from 99 to 69 μM. The finding of those significant differences in the binding of GTP reinforces the hypothesis that the Met139Leu substitution affects strongly the nucleotide binding site of PEPCK-C. PMID:27391465

  14. A role for AMPK in the inhibition of glucose-6-phosphate dehydrogenase by polyunsaturated fatty acids

    SciTech Connect

    Kohan, Alison B.; Talukdar, Indrani; Walsh, Callee M.; Salati, Lisa M.

    2009-10-09

    Both polyunsaturated fatty acids and AMPK promote energy partitioning away from energy consuming processes, such as fatty acid synthesis, towards energy generating processes, such as {beta}-oxidation. In this report, we demonstrate that arachidonic acid activates AMPK in primary rat hepatocytes, and that this effect is p38 MAPK-dependent. Activation of AMPK mimics the inhibition by arachidonic acid of the insulin-mediated induction of G6PD. Similar to intracellular signaling by arachidonic acid, AMPK decreases insulin signal transduction, increasing Ser{sup 307} phosphorylation of IRS-1 and a subsequent decrease in AKT phosphorylation. Overexpression of dominant-negative AMPK abolishes the effect of arachidonic acid on G6PD expression. These data suggest a role for AMPK in the inhibition of G6PD by polyunsaturated fatty acids.

  15. Marigold flower-powder exhibits significant potential to inhibit lipid oxidation in rice bran tea.

    PubMed

    Wanyo, Pitchaporn; Kaewseejan, Niwat; Meeso, Naret; Siriamornpun, Sirithon

    2015-06-01

    We supplemented marigold flower-powder (MFP) in rice bran tea at different proportions as a source of natural antioxidant compounds. Changes of phenolic compounds, antioxidant activity, fatty acid composition and lipid oxidation in the rice bran tea with MFP after 30 days of storage were investigated, comparing results with the initial data. Adding MFP in rice bran tea resulted in an increased content and composition of phenolics and flavonoids along with enhanced antioxidant activities, which were increased in a dose-dependent manner. As a result, MFP supplementation of rice bran tea was able to retard the lipid oxidation as determined by the peroxide value (PV), due to the protection of essential fatty acids during 30 days of storage. The PVs were strongly negatively correlated (p < 0.01) with phenolic compounds, total phenolic content (TPC) and total flavonoid content (TFC), but were positively correlated with tocopherols and γ-oryzanol contents. We also found that the PV was positively correlated with the PUFA (poly unsaturated fatty acid) content but adverse results were found for SFA (saturated fatty acid) and MUFA (mono unsaturated fatty acid) contents. These findings suggest that MFP could be used as a natural antioxidant in foods for preventing lipid oxidation as well as extending the shelf-life of food products. PMID:25927551

  16. Inhibition of ultraviolet-B skin carcinogenesis by all-trans-retinoic acid regimens that inhibit ornithine decarboxylase induction

    SciTech Connect

    Connor, M.J.; Lowe, N.J.; Breeding, J.H.; Chalet, M.

    1983-01-01

    There is a correlation between the ability to induce the polyamine-biosynthetic enzyme ornithine decarboxylase (ODC) and the tumor-promoting ability of various carcinogens in mouse epidermis. Some agents which inhibit skin carcinogenesis also inhibit ODC induction. In this study, all-trans-retinoic acid (RA) regimens that inhibited the induction of epidermal ODC by ultraviolet-B (UVB) were tested for their ability to inhibit UVB skin carcinogenesis. Hairless mice were irradiated once daily with UVB for 20 days, receiving a total dose of UVB (17.1 kJ/sq m). Topical RA was applied immediately (RA, one dose) or applied 0, 1, 2, 3, and 4 hr (RA, five doses) after each irradiance. The mice were maintained for 52 weeks and then sacrificed. Groups treated with RA tended to have fewer mice with tumors, fewer tumors per mouse, smaller tumor diameters, and slower growing tumors than did appropriate irradiated control groups. RA given five times was more effective than was RA given one time at inhibiting UVB skin carcinogenesis. These results show that RA treatments that inhibit epidermal ODC induction may be effective in reducing the carcinogenicity of UVB.

  17. Inhibition of Fatty Acid Oxidation Modulates Immunosuppressive Functions of Myeloid-Derived Suppressor Cells and Enhances Cancer Therapies.

    PubMed

    Hossain, Fokhrul; Al-Khami, Amir A; Wyczechowska, Dorota; Hernandez, Claudia; Zheng, Liqin; Reiss, Krzystoff; Valle, Luis Del; Trillo-Tinoco, Jimena; Maj, Tomasz; Zou, Weiping; Rodriguez, Paulo C; Ochoa, Augusto C

    2015-11-01

    Myeloid-derived suppressor cells (MDSC) promote tumor growth by inhibiting T-cell immunity and promoting malignant cell proliferation and migration. The therapeutic potential of blocking MDSC in tumors has been limited by their heterogeneity, plasticity, and resistance to various chemotherapy agents. Recent studies have highlighted the role of energy metabolic pathways in the differentiation and function of immune cells; however, the metabolic characteristics regulating MDSC remain unclear. We aimed to determine the energy metabolic pathway(s) used by MDSC, establish its impact on their immunosuppressive function, and test whether its inhibition blocks MDSC and enhances antitumor therapies. Using several murine tumor models, we found that tumor-infiltrating MDSC (T-MDSC) increased fatty acid uptake and activated fatty acid oxidation (FAO). This was accompanied by an increased mitochondrial mass, upregulation of key FAO enzymes, and increased oxygen consumption rate. Pharmacologic inhibition of FAO blocked immune inhibitory pathways and functions in T-MDSC and decreased their production of inhibitory cytokines. FAO inhibition alone significantly delayed tumor growth in a T-cell-dependent manner and enhanced the antitumor effect of adoptive T-cell therapy. Furthermore, FAO inhibition combined with low-dose chemotherapy completely inhibited T-MDSC immunosuppressive effects and induced a significant antitumor effect. Interestingly, a similar increase in fatty acid uptake and expression of FAO-related enzymes was found in human MDSC in peripheral blood and tumors. These results support the possibility of testing FAO inhibition as a novel approach to block MDSC and enhance various cancer therapies.

  18. Inhibition of Fatty Acid Oxidation Modulates Immunosuppressive Functions of Myeloid-Derived Suppressor Cells and Enhances Cancer Therapies

    PubMed Central

    Hossain, Fokhrul; Al-Khami, Amir A.; Wyczechowska, Dorota; Hernandez, Claudia; Zheng, Liqin; Reiss, Krzystoff; Del Valle, Luis; Trillo-Tinoco, Jimena; Maj, Tomasz; Zou, Weiping; Rodriguez, Paulo C.; Ochoa, Augusto C.

    2015-01-01

    Myeloid-derived suppressor cells (MDSC) promote tumor growth by inhibiting T-cell immunity and promoting malignant cell proliferation and migration. The therapeutic potential of blocking MDSCs in tumors has been limited by their heterogeneity, plasticity, and resistance to various chemotherapy agents. Recent studies have highlighted the role of energy metabolic pathways in the differentiation and function of immune cells; however, the metabolic characteristics regulating MDSCs remain unclear. We aimed to determine the energy metabolic pathway(s) used by MDSCs, establish its impact on their immunosuppressive function, and test whether its inhibition blocks MDSCs and enhances antitumor therapies. Using several murine tumor models, we found that tumor-infiltrating MDSCs (T-MDSC) increased fatty acid uptake and activated fatty acid oxidation (FAO). This was accompanied by an increased mitochondrial mass, upregulation of key FAO enzymes, and increased oxygen consumption rate. Pharmacologic inhibition of FAO blocked immune inhibitory pathways and functions in T-MDSCs and decreased their production of inhibitory cytokines. FAO inhibition alone significantly delayed tumor growth in a T cell-dependent manner and enhanced the antitumor effect of adoptive T-cell therapy. Furthermore, FAO inhibition combined with low-dose chemotherapy completely inhibited T-MDSCs immunosuppressive effects and induced a significant antitumor effect. Interestingly, a similar increase in fatty acid uptake and expression of FAO-related enzymes was found in human MDSCs in peripheral blood and tumors. These results support the possibility of testing FAO inhibition as a novel approach to block MDSCs and enhance various cancer therapies. PMID:26025381

  19. Lysophosphatidic Acid Inhibits Apoptosis Induced by Cisplatin in Cervical Cancer Cells

    PubMed Central

    Sui, Yanxia; Yang, Ya; Wang, Ji; Li, Yi; Ma, Hongbing; Cai, Hui; Liu, Xiaoping; Zhang, Yong; Wang, Shufeng; Li, Zongfang; Zhang, Xiaozhi; Wang, Jiansheng; Liu, Rui; Yan, Yanli; Xue, Chaofan; Shi, Xiaowei; Tan, Li; Ren, Juan

    2015-01-01

    Cervical cancer is the second most common cause of cancer death in women worldwide. Lysophosphatidic acid (LPA) level has been found significantly increased in the serum of patients with ovarian, cervical, and colon cancers. LPA level in cervical cancer patients is significantly higher than in healthy controls. LPA receptors were found highly expressed in cervical cancer cells, suggesting LPA may play a role in the development of cervical cancer. The aim of this study is to investigate the effect of LPA on the apoptosis induced by cisplatin (DDP) in cervical cancer cell line and the underlying changes in signaling pathways. Our study found that cisplatin induced apoptosis of Hela cell through inhibiting expression of Bcl-2, upregulating the expression of Bax, Fas-L, and the enzyme activity of caspase-3 (p < 0.05); LPA significantly provided protection against the apoptosis induced by cisplatin by inhibiting the above alterations in apoptotic factor caused by cisplatin (p < 0.05). Moreover, PI3K/AKT pathway was found to be important for the LPA antiapoptosis effect, and administration of PI3K/AKT partially reversed the LPA-mediated protection against cisplatin-induced apoptosis (p < 0.05). These findings have shed new lights on the LPA bioactivity in cervical cancer cells and pointed to a possible sensitization scheme through combined administration of PI3K inhibitor and cisplatin for better treatment of cervical cancer patients, especially those with elevated LPA levels. PMID:26366416

  20. Development of Poly Unsaturated Fatty Acid Derivatives of Aspirin for Inhibition of Platelet Function.

    PubMed

    Roy, Jahnabi; Adili, Reheman; Kulmacz, Richard; Holinstat, Michael; Das, Aditi

    2016-10-01

    The inhibition of platelet aggregation is key to preventing conditions such as myocardial infarction and ischemic stroke. Aspirin is the most widely used drug to inhibit platelet aggregation. Aspirin absorption can be improved further to increase its permeability across biologic membranes via esterification or converting the carboxylic acid to an anhydride. There are several reports indicating that ω-3 and ω-6 fatty acids such as linoleic acid, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) separately inhibit platelet aggregation. Herein, we synthesize anhydride conjugates of aspirin with linoleic acid, EPA, and DHA to form aspirin anhydrides that are expected to have higher permeability across cellular membranes. These aspirin-fatty acid anhydrides inhibited platelet aggregation in washed human platelets and platelet-rich plasma in a dose-dependent manner. In particular, the aspirin-DHA anhydride displayed similar effectiveness to aspirin. Platelet aggregation studies conducted in the presence of various platelet agonists indicated that the aspirin-lipid conjugates act through inhibition of the cyclooxygenase (COX)-thromboxane synthase (TXAS) pathway. Hence, we performed detailed biochemical studies using purified COX-1 as well as TXAS stabilized in nanoscale lipid bilayers of nanodiscs to confirm results from the platelet aggregation studies. We show that although all of the aspirin conjugates act through the COX-TXAS pathway by inhibiting COX-1, the parent fatty acids do not act via this pathway. Finally, we studied the hydrolysis of these compounds in buffer and human plasma, and we demonstrate that all of the aspirin-fatty acid conjugates hydrolyze to the parent molecules aspirin and fatty acid in a controlled manner. PMID:27488919

  1. Fast online determination of surfactant inhibition in acidic phase bioreactors.

    PubMed

    Feitkenhauer, H

    2004-01-01

    Surfactants have been shown to inhibit the anaerobic digestion process severely, with the methanogenic microorganisms being the most affected. The diverse nature of surfactants used even in one (e.g. textile finishing) plant makes an online determination of surfactants sometimes very difficult and expensive. Therefore a fast online determination of inhibitory effects on the acidogenic microorganisms (first step of the degradation cascade) can help to give an early warning signal or to calculate a "pseudo"-surfactant concentration. In a two-phase system this information can be used to protect the methanogenic reactor against surfactant overloading and its long term negative effects. In this paper it is shown that the inhibition is a consequence of microbial inhibition and is not caused by an inactivation of extracellular hydrolytic enzymes (released by the cells for biopolymer cleavage). A titration technique was successfully employed to measure the surfactant inhibition in a laboratory-scale acidification reactor. Additional experiments demonstrate (using sodium dodecyl sulfate as the model substance) how inhibitory effects (and strategies to overcome inhibitory effects) can be investigated efficiently.

  2. Comparative brain cholinesterase-inhibiting activity of Glycyrrhiza glabra, Myristica fragrans, ascorbic acid, and metrifonate in mice.

    PubMed

    Dhingra, Dinesh; Parle, Milind; Kulkarni, S K

    2006-01-01

    The central cholinergic pathways play a prominent role in the learning and memory processes. Acetylcholinesterase is an enzyme that inactivates acetylcholine. The present study was undertaken to estimate the acetylcholinesterase- inhibiting activity of extracts of Glycyrrhiza glabra, Myristica fragrans seeds, and ascorbic acid and compare these values with a standard acetylcholinesterase-inhibiting drug, metrifonate. Aqueous extract of G. glabra (150 mg/kg p.o. for 7 successive days), n-hexane extract of M. fragrans seeds (5 mg/kg p.o. for 3 successive days), ascorbic acid (60 mg/kg i.p. for 3 successive days), and metrifonate (50 mg/kg i.p.) were administered to young male Swiss albino mice. Acetylcholinesterase enzyme was estimated in brains of mice. G. glabra, M. fragrans, ascorbic acid, and metrifonate significantly decreased acetylcholinesterase activity as compared with their respective vehicle-treated control groups.

  3. Monohaloacetic acid drinking water disinfection by-products inhibit follicle growth and steroidogenesis in mouse ovarian antral follicles in vitro.

    PubMed

    Jeong, Clara H; Gao, Liying; Dettro, Tyler; Wagner, Elizabeth D; Ricke, William A; Plewa, Michael J; Flaws, Jodi A

    2016-07-01

    Water disinfection greatly reduced the incidence of waterborne diseases, but the reaction between disinfectants and natural organic matter in water leads to the formation of drinking water disinfection by-products (DBPs). DBPs have been shown to be toxic, but their effects on the ovary are not well defined. This study tested the hypothesis that monohalogenated DBPs (chloroacetic acid, CAA; bromoacetic acid, BAA; iodoacetic acid, IAA) inhibit antral follicle growth and steroidogenesis in mouse ovarian follicles. Antral follicles were isolated and cultured with either vehicle or DBPs (0.25-1.00mM of CAA; 2-15μM of BAA or IAA) for 48 and 96h. Follicle growth was measured every 24h and the media were analyzed for estradiol levels at 96h. Exposure to DBPs significantly inhibited antral follicle growth and reduced estradiol levels compared to controls. These data demonstrate that DBP exposure caused ovarian toxicity in vitro. PMID:27151372

  4. Combination of intermittent calorie restriction and eicosapentaenoic acid for inhibition of mammary tumors

    PubMed Central

    Mizuno, Nancy K.; Rogozina, Olga P.; Seppanen, Christine M.; Liao, D. Joshua; Cleary, Margot P.; Grossmann, Michael E.

    2013-01-01

    There are a number of dietary interventions capable of inhibiting mammary tumorigenesis however the effectiveness of dietary combinations is largely unexplored. Here we combined two interventions previously shown individually to inhibit mammary tumor development. The first was the use of the omega-3 fatty acid, eicosapentaenoic acid (EPA), and the second was the implementation of calorie restriction. MMTV-Her2/neu mice were used as a model for human breast cancers which over express Her2/neu. Six groups of mice were enrolled. Half were fed a control (Con) diet with 10.1% fat calories from soy oil, while the other half consumed a diet with 72% fat calories from EPA. Within each diet mice were further divided into ad libitum (AL), chronic calorie restricted (CCR) or intermittent calorie restricted (ICR) groups. Mammary tumor incidence was lowest in ICR-EPA (15%) and highest in AL-Con mice (87%) while AL-EPA, CCR-Con, CCR-EPA and ICR-Con groups had mammary tumor incidence rates of 63%, 47%, 40% and 59% respectively. Survival was effected similarly by the interventions. Consumption of EPA dramatically reduced serum leptin (P<0.02) and increased serum adiponectin in the AL-EPA mice compared to AL-Con mice (P<0.001). Both CCR and ICR decreased serum leptin and IGF-I compared to AL mice but not compared to each other. These results illustrate that mammary tumor inhibition is significantly increased when ICR and EPA are combined as compared to either intervention alone. This response may be related to alterations in the balance of serum growth factors and adipokines. PMID:23550153

  5. DICHLOROACETIC ACID (DCA) INHIBITS PROLIFERATION AND APOPTOSIS IN NORMAL HEPATOCYTES OF MALE F344 RATS

    EPA Science Inventory

    Dichloroacetic acid (DCA} inhibits proliferation and apoptosis in nonnal hepatocytes of
    male F344 rats.

    Large segments of the population are chronically exposed to dichloroacetic acid (DCA}: DCA is a by product of the chlorine disinfection of drinking water, a metab...

  6. Vanadate inhibition of fungal phyA and bacterial appA2 histidine acid phosphatases

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The fungal PhyA protein, which was first identified as an acid optimum phosphomonoesterase (EC 3.1.3.8), could also serve as a vanadate haloperoxidase (EC 1.11.1.10) provided the acid phosphatase activity is shutdown by vanadate. To understand how vanadate inhibits both phytate and pNPP degrading ac...

  7. SOLUBLE HEPATIC δ-AMINOLEVULINIC ACID SYNTHETASE: END-PRODUCT INHIBITION OF THE PARTIALLY PURIFIED ENZYME*

    PubMed Central

    Scholnick, Perry L.; Hammaker, Lydia E.; Marver, Harvey S.

    1969-01-01

    The present study confirms the existence of hepatic δ-aminolevulinic acid synthetase in the cytosol of the liver, suggests that this enzyme may be in transit to the mitochondria, and defines some of the characteristics of the partially purified enzyme. The substrate and cofactor requirements are similar to those of mitochondrial δ-aminolevulinic acid synthetase. Heme strongly inhibits the partially purified enzyme. A number of proteins that bind heme block this inhibition, which explains previous failures to demonstrate heme inhibition in crude systems. End-product inhibition of δ-aminolevulinic acid synthetase in the mitochondria may play an important role in the regulation of heme biosynthesis in eukaryotic cells. PMID:5257968

  8. Modulation of NMDA receptor function by inhibition of D-amino acid oxidase in rodent brain.

    PubMed

    Strick, Christine A; Li, Cheryl; Scott, Liam; Harvey, Brian; Hajós, Mihály; Steyn, Stefanus J; Piotrowski, Mary A; James, Larry C; Downs, James T; Rago, Brian; Becker, Stacey L; El-Kattan, Ayman; Xu, Youfen; Ganong, Alan H; Tingley, F David; Ramirez, Andres D; Seymour, Patricia A; Guanowsky, Victor; Majchrzak, Mark J; Fox, Carol B; Schmidt, Christopher J; Duplantier, Allen J

    2011-01-01

    Observations that N-Methyl-D-Aspartate (NMDA) antagonists produce symptoms in humans that are similar to those seen in schizophrenia have led to the current hypothesis that schizophrenia might result from NMDA receptor hypofunction. Inhibition of D-amino acid oxidase (DAAO), the enzyme responsible for degradation of D-serine, should lead to increased levels of this co-agonist at the NMDA receptor, and thereby provide a therapeutic approach to schizophrenia. We have profiled some of the preclinical biochemical, electrophysiological, and behavioral consequences of administering potent and selective inhibitors of DAAO to rodents to begin to test this hypothesis. Inhibition of DAAO activity resulted in a significant dose and time dependent increase in D-serine only in the cerebellum, although a time delay was observed between peak plasma or brain drug concentration and cerebellum D-serine response. Pharmacokinetic/pharmacodynamic (PK/PD) modeling employing a mechanism-based indirect response model was used to characterize the correlation between free brain drug concentration and D-serine accumulation. DAAO inhibitors had little or no activity in rodent models considered predictive for antipsychotic activity. The inhibitors did, however, affect cortical activity in the Mescaline-Induced Scratching model, produced a modest but significant increase in NMDA receptor-mediated synaptic currents in primary neuronal cultures from rat hippocampus, and resulted in a significant increase in evoked hippocampal theta rhythm, an in vivo electrophysiological model of hippocampal activity. These findings demonstrate that although DAAO inhibition did not cause a measurable increase in D-serine in forebrain, it did affect hippocampal and cortical activity, possibly through augmentation of NMDA receptor-mediated currents.

  9. Mechanism of iron inhibition by stearic acid Langmuir-Blodgett monolayers

    SciTech Connect

    Xing, W.; Shan, Y.; Guo, D.; Lu, T.; Xi, S.

    1995-01-01

    Many organic compounds can be adsorbed onto the interface of a metal and solution to form a thin film that inhibits the corrosion process according to a blocking and/or negative catalytic effect. Using the Langmuir-Blodgett (LB) technique, stearic acid (SA) monolayers were deposited onto the surface of an iron (Fe) electrode to study the inhibition effect and the mechanism of SA in a neutral medium. Molecular orientation and the number of deposited monolayers of SA were shown to have marked effects on inhibition of Fe corrosion. The inhibition mechanism depended mainly on blocking.

  10. Liquid human milk fortifier significantly improves docosahexaenoic and arachidonic acid status in preterm infants.

    PubMed

    Berseth, C L; Harris, C L; Wampler, J L; Hoffman, D R; Diersen-Schade, D A

    2014-09-01

    We report the fatty acid composition of mother׳s own human milk from one of the largest US cohorts of lactating mothers of preterm infants. Milk fatty acid data were used as a proxy for intake at enrollment in infants (n=150) who received human milk with a powder human milk fortifier (HMF; Control) or liquid HMF [LHMF; provided additional 12mg docosahexaenoic acid (DHA), 20mg arachidonic acid (ARA)/100mL human milk]. Mothers provided milk samples (n=129) and reported maternal DHA consumption (n=128). Infant blood samples were drawn at study completion (Study Day 28). Human milk and infant PPL fatty acids were analyzed using capillary column gas chromatography. DHA and ARA were within ranges previously published for US term and preterm human milk. Compared to Control HMF (providing no DHA or ARA), human milk fortified with LHMF significantly increased infant PPL DHA and ARA and improved preterm infant DHA and ARA status.

  11. Inhibition of 2,4-dichlorophenoxyacetic acid-stimulated elongation of pea stem segments by a xyloglucan oligosaccharide

    SciTech Connect

    York, W.S.; Darvill, A.G.; Albersheim, P.

    1984-06-01

    Xyloglucan, isolated from the soluble extracellular polysaccharides of suspension-cultured sycamore (Acer pseudoplatanus) cells, was digested with an endo-..beta..-1,4-glucanase purified from the culture fluid of Trichoderma viride. A nonasaccharide-rich Bio-Gel P-2 fraction of this digest inhibited 2,4-dichlorophenoxyacetic-acid-stimulated elongation of etiolated pea stem segments. The inhibitory activity of this oligosaccharide fraction exhibited a well-define concentraction optimum between 10/sup -2/ and 10/sup -1/ micrograms per milliliter. Another fraction of the same xyloglucan digest, rich in a structurally related heptasaccharide, did not, at similar concentrations, significantly inhibit the elongation. 11 references, 3 figures.

  12. Growth inhibition of Erwinia amylovora and related Erwinia species by neutralized short‑chain fatty acids.

    PubMed

    Konecki, Katrin; Gernold, Marina; Wensing, Annette; Geider, Klaus

    2013-11-01

    Short-chain fatty acids (SCFAs) are used to preserve food and could be a tool for control of fire blight caused by Erwinia amylovora on apple, pear and related rosaceous plants. Neutralized acids were added to buffered growth media at 0.5–75 mM and tested at pHs ranging from 6.8 to 5.5. Particularly at low pH, SCFAs with a chain length exceeding that of acetic acid such as propionic acid were effective growth inhibitors of E. amylovora possibly due to uptake of free acid and its intracellular accumulation. We also observed high inhibition with monochloroacetic acid. An E. billingiae strain was as sensitive to the acids as E. amylovora or E. tasmaniensis. Fire blight symptoms on pear slices were reduced when the slices were pretreated with neutralized propionic acid. Propionic acid is well water soluble and could be applied in orchards as a control agent for fire blight.

  13. In vitro inhibition of human cytomegalovirus replication by calcium trinatrium diethylenetriaminepentaacetic acid.

    PubMed

    Cinatl, J; Hoffmann, F; Cinatl, J; Weber, B; Scholz, M; Rabenau, H; Stieneker, F; Kabickova, H; Blasko, M; Doerr, H W

    1996-06-01

    Desferrioxamine (DFO) has been shown to inhibit human cytomegalovirus (CMV) replication in vitro. In the present study, we compared antiviral effects of DFO in human foreskin fibroblast (HFF) cells against several CMV strains with those of other chelators that interact with iron and other ions from different pools. DFO, a hydrophilic chelator, that may chelate both intracellular and extracellular ions inhibited production of CMV late antigen at 50% effective concentrations (EC50S) ranging from 6.2 to 8.9 microM. EC50S for calcium trinatrium diethylenetriaminepentaacetic acid (CaDTPA) ranged from 6.1 to 9.9 microM. EC50S for 2,2'-bipyridine (BPD), a hydrophobic chelator, which diffuses into cell membranes ranged from 65 to 72 microM. Concentrations which inhibited BrdU incorporation into cellular DNA by 50% (IC50S) ranged from 8.2 to 12.0 microM (DFO), from 65 to 89 microM (BPD), and from 139 to 249 microM (CaDTPA). CaDTPA was the only chelator which completely inhibited production of infectious virus in HFF and vascular endothelial cells at concentrations which had no significant effects on cellular DNA synthesis and growth. Addition of stoichiometric amounts of Fe3+ in the culture medium of HFF cells completely eliminated antiviral effects of DFO while antiviral effects of CaDTPA and BPD were only moderately affected. Fe2+ and Cu2+ were stronger inhibitors of CaDTPA than Fe3+; however, Mn2+ and Zn2+ completely suppressed antiviral effects of CaDTPA. The results show that CaDTPA is a novel nontoxic inhibitor of CMV replication. The antiviral activity of CaDTPA is suppressed by metal ions with a decreasing potency order of Mn2+/Zn2+ > Fe2+ > Cu2+ > Fe3+.

  14. Uric acid induces oxidative stress and growth inhibition by activating adenosine monophosphate-activated protein kinase and extracellular signal-regulated kinase signal pathways in pancreatic β cells.

    PubMed

    Zhang, Yongneng; Yamamoto, Tetsuya; Hisatome, Ichiro; Li, Youfeng; Cheng, Weijie; Sun, Ning; Cai, Bozhi; Huang, Tianliang; Zhu, Yuzhang; Li, Zhi; Jing, Xubin; Zhou, Rui; Cheng, Jidong

    2013-08-15

    Hyperuricaemia is a disorder of purine metabolism, and is strongly associated with insulin resistance and abnormal glucose metabolism. As the producer of insulin, pancreatic β cells might be affected by elevated serum uric acid levels and contribute to the disregulated glucose metabolism. In this study, we investigated the effect of high uric acid on rat pancreatic β cell function. Under high uric acid condition, proliferation of pancreatic β cells was inhibited, production of reactive oxygen species increased, and glucose stimulated insulin secretion was also compromised. Further examination on signal transduction pathways revealed that uric acid-induced ROS is involved in the activation of adenosine monophosphate-activated protein kinase (AMPK), and extracellular signal-regulated kinase (ERK). Pharmacological inhibition of ERK activation rescued β cells from growth inhibition. More importantly, activation of ERK induced by uric acid is significantly diminished by AMPK inhibitor, indicating ERK as a downstream target of AMPK in response to high uric acid condition. We also investigated the transportation channel for uric acid into pancreatic β cells. While major urate transporter URAT1 is not expressed in β cells, organic anion transporter (OAT) inhibitor successfully blocked the activation of ERK by uric acid. Our data indicate that high uric acid levels induce oxidative damage and inhibit growth of rat pancreatic β cells by activating the AMPK and ERK signal pathways. Hyperuricemia may contribute to abnormal glucose metabolism by causing oxidative damage and function inhibition of pancreatic β cells.

  15. Citric acid inhibits development of cataracts, proteinuria and ketosis in streptozotocin (type 1) diabetic rats.

    PubMed

    Nagai, Ryoji; Nagai, Mime; Shimasaki, Satoko; Baynes, John W; Fujiwara, Yukio

    2010-02-26

    Although many fruits such as lemon and orange contain citric acid, little is known about beneficial effects of citric acid on health. Here we measured the effect of citric acid on the pathogenesis of diabetic complications in streptozotocin-induced diabetic rats. Although oral administration of citric acid to diabetic rats did not affect blood glucose concentration, it delayed the development of cataracts, inhibited accumulation of advanced glycation end-products (AGEs) such as N(epsilon)-(carboxyethyl)lysine (CEL) and N(epsilon)-(carboxymethyl)lysine (CML) in lens proteins, and protected against albuminuria and ketosis. We also show that incubation of protein with acetol, a metabolite formed from acetone by acetone monooxygenase, generate CEL, suggesting that inhibition of ketosis by citric acid may lead to the decrease in CEL in lens proteins. These results demonstrate that the oral administration of citric acid ameliorates ketosis and protects against the development of diabetic complications in an animal model of type 1 diabetes.

  16. Role of hydroxyl group in the inhibitive action of benzoic acid toward corrosion of aluminum in nitric acid

    SciTech Connect

    Yadav, P.N.S.; Singh, A.K.; Wadhwani, R.

    1999-10-01

    Corrosion inhibition action of benzoic acid, p-hydroxy benzoic acid, 2-4-dihydroxy benzoic acid, and 3-4-5-trihydroxy benzoic acid toward aluminum alloy 3003 (UNS A93003) in 20% (wt%) nitric acid (HNO{sub 3}) using different concentrations of these compounds at 30 C, 40 C, and 50 C has been studied thoroughly. 3-4-5-trihydroxy benzoic acid (inhibition efficiency (IE): 30% and 72%) was the most effective inhibitor followed by 2-4-dihydroxy benzoic acid (IE: 22% to 62%) p-hydroxy benzoic acid (IE: 11% to 52%), and benzoic acid (IE: 2.5% to 15%). IE increased with concentration and its maximum value was observed at 0.5% concentration of all inhibitors used. The percentage of IE of the inhibitors decreased with an increase in temperature from 30 C to 50 C. Values of heat adsorption and activation energy were calculated from weight loss data, which came out in the range for the reaction occurring at the surface. The behavior of inhibitors studied deviated from the Langmuir isotherm. The IE of higher hydroxy species was improved when more hydroxy centers were added. Anodic and cathodic polarization curves were shifted toward lower current density regions in the presence of inhibitors. This revealed that they were mixed inhibitors.

  17. Ellagic acid promotes A{beta}42 fibrillization and inhibits A{beta}42-induced neurotoxicity

    SciTech Connect

    Feng, Ying; Yang, Shi-gao; Du, Xue-ting; Zhang, Xi; Sun, Xiao-xia; Zhao, Min; Sun, Gui-yuan; Liu, Rui-tian

    2009-12-25

    Smaller, soluble oligomers of {beta}-amyloid (A{beta}) play a critical role in the pathogenesis of Alzheimer's disease (AD). Selective inhibition of A{beta} oligomer formation provides an optimum target for AD therapy. Some polyphenols have potent anti-amyloidogenic activities and protect against A{beta} neurotoxicity. Here, we tested the effects of ellagic acid (EA), a polyphenolic compound, on A{beta}42 aggregation and neurotoxicity in vitro. EA promoted A{beta} fibril formation and significant oligomer loss, contrary to previous results that polyphenols inhibited A{beta} aggregation. The results of transmission electron microscopy (TEM) and Western blot displayed more fibrils in A{beta}42 samples co-incubated with EA in earlier phases of aggregation. Consistent with the hypothesis that plaque formation may represent a protective mechanism in which the body sequesters toxic A{beta} aggregates to render them harmless, our MTT results showed that EA could significantly reduce A{beta}42-induced neurotoxicity toward SH-SY5Y cells. Taken together, our results suggest that EA, an active ingredient in many fruits and nuts, may have therapeutic potential in AD.

  18. Salicylhydroxamic acid (SHAM) inhibition of the dissolved inorganic carbon concentrating process in unicellular green algae

    SciTech Connect

    Goyal, A.; Tolbert, N.E. )

    1990-03-01

    Rates of photosynthetic O{sub 2} evolution, for measuring K{sub 0.5}(CO{sub 2} + HCO{sub 3}{sup {minus}}) at pH 7, upon addition of 50 micromolar HCO{sub 3}{sup {minus}} to air-adapted Chlamydomonas, Dunaliella, or Scenedesmus cells, were inhibited up to 90% by the addition of 1.5 to 4.0 millimolar salicylhydroxamic acid (SHAM) to the aqueous medium. The apparent K{sub i}(SHAM) for Chlamydomonas cells was about 2.5 millimolar, but due to low solubility in water effective concentrations would be lower. Salicylhydroxamic acid did not inhibit oxygen evolution or accumulation of bicarbonate by Scenedesmus cells between pH 8 to 11 or by isolated intact chloroplasts from Dunaliella. Thus, salicylhydroxamic acid appears to inhibit CO{sub 2} uptake, whereas previous results indicate that vanadate inhibits bicarbonate uptake. These conclusions were confirmed by three test procedures with three air-adapted algae at pH 7. Salicylhydroxamic acid inhibited the cellular accumulation of dissolved inorganic carbon, the rate of photosynthetic O{sub 2} evolution dependent on low levels of dissolved inorganic carbon (50 micromolar NaHCO{sub 3}), and the rate of {sup 14}CO{sub 2} fixation with 100 micromolar ({sup 14}C)HCO{sub 3}{sup {minus}}. Salicylhydroxamic acid inhibition of O{sub 2} evolution and {sup 14}CO{sub 2}-fixation was reversed by higher levels of NaHCO{sub 3}. Thus, salicylhydroxamic acid inhibition was apparently not affecting steps of photosynthesis other than CO{sub 2} accumulation. Although salicylhydroxamic acid is an inhibitor of alternative respiration in algae, it is not known whether the two processes are related.

  19. Salicylhydroxamic Acid (SHAM) Inhibition of the Dissolved Inorganic Carbon Concentrating Process in Unicellular Green Algae.

    PubMed

    Goyal, A; Tolbert, N E

    1990-03-01

    Rates of photosynthetic O(2) evolution, for measuring K(0.5)(CO(2) + HCO(3) (-)) at pH 7, upon addition of 50 micromolar HCO(3) (-) to air-adapted Chlamydomonas, Dunaliella, or Scenedesmus cells, were inhibited up to 90% by the addition of 1.5 to 4.0 millimolar salicylhydroxamic acid (SHAM) to the aqueous medium. The apparent K(1)(SHAM) for Chlamydomonas cells was about 2.5 millimolar, but due to low solubility in water effective concentrations would be lower. Salicylhydroxamic acid did not inhibit oxygen evolution or accumulation of bicarbonate by Scenedesmus cells between pH 8 to 11 or by isolated intact chloroplasts from Dunaliella. Thus, salicylhydroxamic acid appears to inhibit CO(2) uptake, whereas previous results indicate that vanadate inhibits bicarbonate uptake. These conclusions were confirmed by three test procedures with three air-adapted algae at pH 7. Salicylhydroxamic acid inhibited the cellular accumulation of dissolved inorganic carbon, the rate of photosynthetic O(2) evolution dependent on low levels of dissolved inorganic carbon (50 micromolar Na-HCO(3)), and the rate of (14)CO(2) fixation with 100 micromolar [(14)C] HCO(3) (-). Salicylhydroxamic acid inhibition of O(2) evolution and (14)CO(2)-fixation was reversed by higher levels of NaHCO(3). Thus, salicylhydroxamic acid inhibition was apparently not affecting steps of photosynthesis other than CO(2) accumulation. Although salicylhydroxamic acid is an inhibitor of alternative respiration in algae, it is not known whether the two processes are related.

  20. Evidence for inhibition of exodus of small neutral amino acids from non-brain tissues in hyperphenylalaninaemic rats.

    PubMed

    de Cespedes, C; Thoene, J G; Lowler, K; Christensen, H N

    1989-01-01

    The mechanism of the depletion of several plasma amino acids in PKU has remained unexplained. In the present study, a statistically significant decrease in the plasma concentration of several amino acids was observed 2 h after the intraperitoneal injection of Phe to weanling rats. The pattern was very similar to the one observed in PKU patients. Statistically significant increases in the distribution ratios liver/plasma and, mainly, muscle/plasma ratios accompanied in most of the cases the corresponding decreases in plasma concentrations. Equimolar injection under the same conditions of the non-insulinogenic transport system L analogue, the a(+/-) isomer of the 2-aminonorbornane-2-carboxylic acid, produced, in a parallel effect to Phe, statistically significant increases in the distribution ratios of Ala and Gly, and probably of Pro in muscle, as well as of Ala in liver. These results seem to indicate that the high intracellular Phe attained inhibits the exodus of small neutral amino acids through system L, causing their depletion in plasma and ultimately in the brain. This effect may be additive to the inhibition by Phe of the entry of bulky neutral amino acids at the level of the blood-brain barrier. Further study is needed to assess the relevance of these effects to PKU.

  1. Labdanolic acid methyl ester (LAME) exerts anti-inflammatory effects through inhibition of TAK-1 activation

    SciTech Connect

    Cuadrado, Irene; Estevez-Braun, Ana; Heras, Beatriz de las

    2012-01-01

    Labdane derivatives obtained from the diterpenoid labdanediol suppressed NO and PGE{sub 2} production in LPS-stimulated RAW 264.7 macrophages. However, mechanisms involved in these inhibitory effects are not elucidated. In this study, we investigated the signaling pathways involved in the anti-inflammatory effects of labdanolic acid methyl ester (LAME) in peritoneal macrophages and examined its therapeutic effect in a mouse endotoxic shock model. LAME reduced the production of NO and PGE{sub 2} in LPS-activated macrophages. This effect involved the inhibition of NOS-2 and COX-2 gene expression, acting at the transcription level. Examination of the effects of the diterpene on NF-κB signaling showed that LAME inhibits the phosphorylation of IκBα and IκBβ, preventing their degradation and the nuclear translocation of the NF-κB p65 subunit. Moreover, inhibition of MAPK signaling was also observed. A further experiment revealed that LAME inhibited the phosphorylation of transforming growth factor-β (TGF-β)-activated kinase 1 (TAK1), an upstream signaling molecule required for IKK and mitogen-activated protein kinases (MAPKs) activation. Inflammatory cytokines such as IL-6, TNF-α and IP-10 were downregulated in the presence of this compound after stimulation with LPS. Additionally, LAME also improved survival in a mouse model of endotoxemia and reduced the circulatory levels of cytokines (IL-6, TNF-α). In conclusion, these results indicate that labdane diterpene LAME significantly attenuates the pro-inflammatory response induced by LPS both in vivo and in vitro. Highlights: ► LAME reduced the production of NO and PGE{sub 2} in LPS-activated macrophages. ► IL-6, TNF-α and IP-10 were also inhibited by LAME. ► Inhibition of TAK-1 activation is the mechanism involved in this process. ► LAME improved survival in a mouse model of endotoxemia. ► LAME reduced the circulatory levels of cytokines (IL-6, TNF-α).

  2. Gambogic acid induces apoptosis in diffuse large B-cell lymphoma cells via inducing proteasome inhibition

    PubMed Central

    Shi, Xianping; Lan, Xiaoying; Chen, Xin; Zhao, Chong; Li, Xiaofen; Liu, Shouting; Huang, Hongbiao; Liu, Ningning; Zang, Dan; Liao, Yuning; Zhang, Peiquan; Wang, Xuejun; Liu, Jinbao

    2015-01-01

    Resistance to chemotherapy is a great challenge to improving the survival of patients with diffuse large B-cell lymphoma (DLBCL), especially those with activated B-cell-like DLBCL (ABC-DLBCL). Therefore it is urgent to search for novel agents for the treatment of DLBCL. Gambogic acid (GA), a small molecule derived from Chinese herb gamboges, has been approved for Phase II clinical trial for cancer therapy by Chinese FDA. In the present study, we investigated the effect of GA on cell survival and apoptosis in DLBCL cells including both GCB- and ABC-DLBCL cells. We found that GA induced growth inhibition and apoptosis of both GCB- and ABC-DLBCL cells in vitro and in vivo, which is associated with proteasome malfunction. These findings provide significant pre-clinical evidence for potential usage of GA in DLBCL therapy particularly in ABC-DLBCL treatment. PMID:25853502

  3. Clavulanic acid inhibits MPP⁺-induced ROS generation and subsequent loss of dopaminergic cells.

    PubMed

    Kost, Gina Chun; Selvaraj, Senthil; Lee, Young Bok; Kim, Deog Joong; Ahn, Chang-Ho; Singh, Brij B

    2012-08-21

    Clavulanic acid is a psychoactive compound that has been shown to modulate central nervous system activity. Importantly, in neurotoxin-induced animal models, clavulanic acid has been shown to improve motor function (Huh et al., 2010) suggesting that it can be neuroprotective; however, the mechanism as how clavulanic acid can induce neuroprotection is not known. We demonstrate here that clavulanic acid abrogates the effects of the neurotoxin 1-methyl-4-phenylpyridinium (MPP(+)) which mimics Parkinson's disease (PD) by inducing neurodegeneration. To further establish the mechanism we identified that clavulanic acid inhibits neurotoxin-induced loss of mitochondrial membrane potential and ROS production. Consistent with these results, neurotoxin-induced increase in Bax levels was also decreased in clavulanic acid treated cells. Importantly, neurotoxin-induced release of cytochrome c levels as well as caspase activation was also inhibited in clavulanic acid treated cells. In addition, Bcl-xl levels were also restored and the Bcl-xl/Bax ratio that is critical for inducing apoptosis was increased in clavulanic acid treated cells. Overall, these results suggest that clavulanic acid is intimately involved in inhibiting neurotoxin-induced loss of mitochondrial function and induction of apoptosis that contributes towards neuronal survival.

  4. Clavulanic acid inhibits MPP+-induced ROS generation and subsequent loss of dopaminergic cells☆

    PubMed Central

    Kost, Gina Chun; Selvaraj, Senthil; Lee, Young Bok; Kim, Deog Joong; Ahn, Chang-Ho; Singh, Brij B.

    2013-01-01

    Clavulanic acid is a psychoactive compound that has been shown to modulate central nervous system activity. Importantly, in neurotoxin-induced animal models, clavulanic acid has been shown to improve motor function (Huh et al., 2010) suggesting that it can be neuroprotective; however, the mechanism as how clavulanic acid can induce neuroprotection is not known. We demonstrate here that clavulanic acid abrogates the effects of the neurotoxin 1-methyl-4-phenylpyridinium (MPP+) which mimics Parkinson’s disease (PD) by inducing neurodegeneration. To further establish the mechanism we identified that clavulanic acid inhibits neurotoxin-induced loss of mitochondrial membrane potential and ROS production. Consistent with these results, neurotoxin-induced increase in Bax levels was also decreased in clavulanic acid treated cells. Importantly, neurotoxin-induced release of cytochrome c levels as well as caspase activation was also inhibited in clavulanic acid treated cells. In addition, Bcl-xl levels were also restored and the Bcl-xl/Bax ratio that is critical for inducing apoptosis was increased in clavulanic acid treated cells. Overall, these results suggest that clavulanic acid is intimately involved in inhibiting neurotoxin-induced loss of mitochondrial function and induction of apoptosis that contributes towards neuronal survival. PMID:22750587

  5. Inhibition of enterobacteria and Listeria growth by lactic, acetic and formic acids.

    PubMed

    Ostling, C E; Lindgren, S E

    1993-07-01

    Minimum inhibitory concentrations (MIC) of undissociated lactic, acetic and formic acids were evaluated for 23 strains of enterobacteria and two of Listeria monocytogenes. The evaluation was performed aerobically and anaerobically in a liquid test system at pH intervals of between 4.2 and 5.4. Growth of the enterobacteria was inhibited at 2-11 mmol l-1, 0.5-14 mmol l-1 and 0.1-1.5 mmol l-1 of undissociated lactic, acetic and formic acids, respectively. The MIC value was slightly lower with anaerobic conditions compared with aerobic conditions. The influence of protons on the inhibition was observed for acetic acid at the low pH values. Undissociated lactic acid was 2 to 5 times more efficient in inhibiting L. monocytogenes than enterobacteria. Acetic acid had a similar inhibitory action on L. monocytogenes compared with enterobacteria. Inorganic acid (HCl) inhibited most enterobacteria at pH 4.0; some strains, however, were able to initiate growth to pH 3.8. The results indicate that the values of undissociated acid which occur in a silage of pH 4.1-4.5 are about 10-100 times higher than required in order to protect the forage from the growth of enterobacteria and L. monocytogenes.

  6. Docosahexaenoic acid content is significantly higher in ghrita prepared by traditional Ayurvedic method

    PubMed Central

    Joshi, Kalpana S.

    2014-01-01

    Background: Ghee (clarified butter) also known as ghrita, has been utilized for thousands of years in Ayurveda. Ghee is mostly prepared by traditional method in Indian households or by direct cream method at industry level. Ayurvedic classics mention that ghrita made from cow milk is superior. However, there is no scientific comparison available on preparation methods and essential fatty acids content of ghrita. Objective: To investigate fatty acid composition of ghrita prepared by traditional/Ayurvedic method and commercial method (direct cream method). Materials and Methods: Fatty Acid Methyl Esters (FAME) extracted from ghrita samples were analysed on Gas Chromatography (GC) Shimadzu B using capillary column BPX70 (0.32 mm*60 m, ID of 0.25 mm). The fatty acids in the samples were identified by comparing peaks with the external standard 68A (Nu-Chek-Prep, Inc.USA). Significant differences between the experimental groups were assessed by analysis of variance. Results: Distribution of fatty acids was compared in ghrita samples prepared by traditional method and direct cream method which is commercially used. Saturated fatty acids were predominant in both the groups. Mono unsaturated fatty acids and poly unsaturated fatty acids were in the range of 17-18% and 3-6% respectively. DHA content was significantly higher in ghee prepared by traditional method using curd starter fermentation. Conclusion: The findings suggested that ghrita prepared by traditional ayurvedic methods contains higher amount of DHA; Omega-3 long-chain polyunsaturated fatty acids, which is a major component of retinal and brain tissues and remains important in prevention of various diseases. PMID:24948858

  7. Punicalagin and Ellagic Acid Demonstrate Antimutagenic Activity and Inhibition of Benzo[a]pyrene Induced DNA Adducts

    PubMed Central

    Zahin, Maryam; Ahmad, Iqbal; Gupta, Ramesh C.; Aqil, Farrukh

    2014-01-01

    Punicalagin (PC) is an ellagitannin found in the fruit peel of Punica granatum. We have demonstrated antioxidant and antigenotoxic properties of Punica granatum and showed that PC and ellagic acid (EA) are its major constituents. In this study, we demonstrate the antimutagenic potential, inhibition of BP-induced DNA damage, and antiproliferative activity of PC and EA. Incubation of BP with rat liver microsomes, appropriate cofactors, and DNA in the presence of vehicle or PC and EA showed significant inhibition of the resultant DNA adducts, with essentially complete inhibition (97%) at 40 μM by PC and 77% inhibition by EA. Antimutagenicity was tested by Ames test. PC and EA dose-dependently and markedly antagonized the effect of tested mutagens, sodium azide, methyl methanesulfonate, benzo[a]pyrene, and 2-aminoflourine, with maximum inhibition of mutagenicity up to 90 percent. Almost all the doses tested (50–500 μM) exhibited significant antimutagenicity. A profound antiproliferative effect on human lung cancer cells was also shown with PC and EA. Together, our data show that PC and EA are pomegranate bioactives responsible for inhibition of BP-induced DNA adducts and strong antimutagenic, antiproliferative activities. However, these compounds are to be evaluated in suitable animal model to assess their therapeutic efficacy against cancer. PMID:24949451

  8. Inhibition of lymphoid tyrosine phosphatase by benzofuran salicylic acids.

    PubMed

    Vang, Torkel; Xie, Yuli; Liu, Wallace H; Vidović, Dusica; Liu, Yidong; Wu, Shuangding; Smith, Deborah H; Rinderspacher, Alison; Chung, Caty; Gong, Gangli; Mustelin, Tomas; Landry, Donald W; Rickert, Robert C; Schürer, Stephan C; Deng, Shi-Xian; Tautz, Lutz

    2011-01-27

    The lymphoid tyrosine phosphatase (Lyp, PTPN22) is a critical negative regulator of T cell antigen receptor (TCR) signaling. A single-nucleotide polymorphism (SNP) in the ptpn22 gene correlates with the incidence of various autoimmune diseases, including type 1 diabetes, rheumatoid arthritis, and systemic lupus erythematosus. Since the disease-associated allele is a more potent inhibitor of TCR signaling, specific Lyp inhibitors may become valuable in treating autoimmunity. Using a structure-based approach, we synthesized a library of 34 compounds that inhibited Lyp with IC(50) values between 0.27 and 6.2 μM. A reporter assay was employed to screen for compounds that enhanced TCR signaling in cells, and several inhibitors displayed a dose-dependent, activating effect. Subsequent probing for Lyp's direct physiological targets by immunoblot analysis confirmed the ability of the compounds to inhibit Lyp in T cells. Selectivity profiling against closely related tyrosine phosphatases and in silico docking studies with the crystal structure of Lyp yielded valuable information for the design of Lyp-specific compounds. PMID:21190368

  9. Epoxygenase metabolites of arachidonic acid inhibit vasopressin response in toad bladder

    SciTech Connect

    Schlondorff, D.; Petty, E.; Oates, J.A.; Jacoby, M.; Levine, S.D. Vanderbilt Univ., Nashville, TN )

    1987-09-01

    In addition to cyclooxygenase and lipoxygenase pathways, the kidney can also metabolize arachidonic acid by a NADPH-dependent cytochrome P-450 enzyme to epoxyeicosatrienoic acids (EETs); furthermore, 5,6-EET has been shown to alter electrolyte transport across isolated renal tubules. The authors examined the effects of three ({sup 14}C-labeled)-EETs (5,6-, 11,12-, and 14,15-EET) on osmotic water flow across toad urinary bladder. All three EETs reversibly inhibited vasopressin-stimulated osmotic water flow with 5,6- and 11,12-EET being the most potent. The effects appeared to be independent of prostaglandins EETs inhibited the water flow response to forskolin but not the response to adenosine 3{prime},5{prime}-cyclic monophosphate (cAMP) or 8-BrcAMP, consistent with an effect on cAMP generation. To determine whether these effects were due to the EETs or to products of their metabolism, they examined the effects of their vicinal diol hydrolysis products, the dihydroxyeicosatrienoic acids. Nonenzymatic conversion of labeled 5,6-EET to its vicinal diol occurred rapidly in the buffer, whereas 11,12-EET was hydrolyzed in a saturable manner only when incubated in the presence of bladder tissue. The dihydroxyeicosatrienoic acids formed inhibited water flow in a manner paralleling that of the EETs. The data support the hypothesis that EETs and their physiologically active dihydroxyeicosatrienoic acid metabolites inhibit vasopressin-stimulated water flow predominantly via inhibition of adenylate cyclase.

  10. Molecular mechanism and functional significance of acid generation in the Drosophila midgut

    PubMed Central

    Overend, Gayle; Luo, Yuan; Henderson, Louise; Douglas, Angela E.; Davies, Shireen A.; Dow, Julian A. T.

    2016-01-01

    The gut of Drosophila melanogaster includes a proximal acidic region (~pH 2), however the genome lacks the H+/K+ ATPase characteristic of the mammalian gastric parietal cell, and the molecular mechanisms of acid generation are poorly understood. Here, we show that maintenance of the low pH of the acidic region is dependent on H+ V-ATPase, together with carbonic anhydrase and five further transporters or channels that mediate K+, Cl− and HCO3− transport. Abrogation of the low pH did not influence larval survival under standard laboratory conditions, but was deleterious for insects subjected to high Na+ or K+ load. Insects with elevated pH in the acidic region displayed increased susceptibility to Pseudomonas pathogens and increased abundance of key members of the gut microbiota (Acetobacter and Lactobacillus), suggesting that the acidic region has bacteriostatic or bacteriocidal activity. Conversely, the pH of the acidic region was significantly reduced in germ-free Drosophila, indicative of a role of the gut bacteria in shaping the pH conditions of the gut. These results demonstrate that the acidic gut region protects the insect and gut microbiome from pathological disruption, and shed light on the mechanisms by which low pH can be maintained in the absence of H+, K+ ATPase. PMID:27250760

  11. Mechanism of cinnamic acid-induced trypsin inhibition: a multi-technique approach.

    PubMed

    Zhang, Hongmei; Zhou, Qiuhua; Cao, Jian; Wang, Yanqing

    2013-12-01

    In order to investigate the association of the protease trypsin with cinnamic acid, the interaction was characterized by using fluorescence, UV-vis absorption spectroscopy, molecular modeling and an enzymatic inhibition assay. The binding process may be outlined as follows: cinnamic acid can interact with trypsin with one binding site to form cinnamic acid-trypsin complex, resulting in inhibition of trypsin activity; the spectroscopic data show that the interaction is a spontaneous process with the estimated enthalpy and entropy changes being -8.95 kJ mol(-1) and 50.70 J mol(-1) K(-1), respectively. Noncovalent interactions make the main contribution to stabilize the trypsin-cinnamic acid complex; cinnamic acid can enter into the primary substrate-binding pocket and alter the environment around Trp and Tyr residues.

  12. Irreversible inhibition of human immunodeficiency virus type 1 integrase by dicaffeoylquinic acids.

    PubMed

    Zhu, K; Cordeiro, M L; Atienza, J; Robinson, W E; Chow, S A

    1999-04-01

    Human immunodeficiency virus type 1 (HIV-1) and other retroviruses require integration of a double-stranded DNA copy of the RNA genome into the host cell chromosome for productive infection. The viral enzyme, integrase, catalyzes the integration of retroviral DNA and represents an attractive target for developing antiretroviral agents. We identified several derivatives of dicaffeoylquinic acids (DCQAs) that inhibit HIV-1 replication in tissue culture and catalytic activities of HIV-1 integrase in vitro. The specific step at which DCQAs inhibit the integration in vitro and the mechanism of inhibition were examined in the present study. Titration experiments with different concentrations of HIV-1 integrase or DNA substrate found that the effect of DCQAs was exerted on the enzyme and not the DNA. In addition to HIV-1, DCQAs also inhibited the in vitro activities of MLV integrase and truncated variants of feline immunodeficiency virus integrase, suggesting that these compounds interacted with the central core domain of integrase. The inhibition on retroviral integrases was relatively specific, and DCQAs had no effect on several other DNA-modifying enzymes and phosphoryltransferases. Kinetic analysis and dialysis experiments showed that the inhibition of integrase by DCQAs was irreversible. The inhibition did not require the presence of a divalent cation and was unaffected by preassembling integrase onto viral DNA. The results suggest that the irreversible inhibition by DCQAs on integrase is directed toward conserved amino acid residues in the central core domain during catalysis.

  13. Phyllostachys edulis Compounds Inhibit Palmitic Acid-Induced Monocyte Chemoattractant Protein 1 (MCP-1) Production

    PubMed Central

    Higa, Jason K.; Liang, Zhibin; Williams, Philip G.; Panee, Jun

    2012-01-01

    Background Phyllostachys edulis Carriere (Poaceae) is a bamboo species that is part of the traditional Chinese medicine pharmacopoeia. Compounds and extracts from this species have shown potential applications towards several diseases. One of many complications found in obesity and diabetes is the link between elevated circulatory free fatty acids (FFAs) and chronic inflammation. This study aims to present a possible application of P. edulis extract in relieving inflammation caused by FFAs. Monocyte chemoattractant protein 1 (MCP-1/CCL2) is a pro-inflammatory cytokine implicated in chronic inflammation. Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and activator protein 1 (AP-1) are transcription factors activated in response to inflammatory stimuli, and upregulate pro-inflammatory cytokines such as MCP-1. This study examines the effect of P. edulis extract on cellular production of MCP-1 and on the NF-κB and AP-1 pathways in response to treatment with palmitic acid (PA), a FFA. Methodology/Principal Findings MCP-1 protein was measured by cytometric bead assay. NF-κB and AP-1 nuclear localization was detected by colorimetric DNA-binding ELISA. Relative MCP-1 mRNA was measured by real-time quantitative PCR. Murine cells were treated with PA to induce inflammation. PA increased expression of MCP-1 mRNA and protein, and increased nuclear localization of NF-κB and AP-1. Adding bamboo extract (BEX) inhibited the effects of PA, reduced MCP-1 production, and inhibited nuclear translocation of NF-κB and AP-1 subunits. Compounds isolated from BEX inhibited MCP-1 secretion with different potencies. Conclusions/Significance PA induced MCP-1 production in murine adipose, muscle, and liver cells. BEX ameliorated PA-induced production of MCP-1 by inhibiting nuclear translocation of NF-κB and AP-1. Two O-methylated flavones were isolated from BEX with functional effects on MCP-1 production. These results may represent a possible therapeutic

  14. Retinoic acid inhibits endometrial cancer cell growth via multiple genomic mechanisms.

    PubMed

    Cheng, You-Hong; Utsunomiya, Hiroki; Pavone, Mary Ellen; Yin, Ping; Bulun, Serdar E

    2011-04-01

    Previous studies have indicated that retinoic acid (RA) may be therapeutic for endometrial cancer. However, the downstream target genes and pathways triggered by ligand-activated RA receptor α (RARα) in endometrial cancer cells are largely unknown. In this study, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, flow cytometry, and immunoblotting assays were used to assess the roles of RA and the RA agonist (AM580) in the growth of endometrial cancer cells. Illumina-based microarray expression profiling of endometrial Ishikawa cells incubated with and without AM580 for 1, 3, and 6 h was performed. We found that both RA and AM580 markedly inhibited endometrial cancer cell proliferation, while knockdown of RARα could block AM580 inhibition. Knockdown of RARα significantly increased proliferating cell nuclear antigen and BCL2 protein levels. Incubation of Ishikawa cells with or without AM580 followed by microarray expression profiling showed that 12 768 genes out of 47 296 gene probes were differentially expressed with significant P values. We found that 90 genes were the most regulated genes with the most significant P value (P<0.0001) using F-test. We selected four highly regulated genes with diverse functions, namely G0S2, TNFAIP2, SMAD3, and NRIP1. Real-time PCR verified that AM580 highly regulated these genes, whereas chromatin immunoprecipitation-PCR assay demonstrated that ligand-activated RARα interacted with the promoter of these genes in intact endometrial cancer cells. AM580 also significantly altered 18 pathways including those related to cell growth, differentiation, and apoptosis. In conclusion, AM580 treatment of Ishikawa cells causes the differential expression of a number of RARα target genes and activation of signaling pathways. These pathways could, therefore, mediate the carcinogenesis of human endometrial cancer.

  15. Kinetics of Inhibition of Monoamine Oxidase Using Curcumin and Ellagic Acid

    PubMed Central

    Khatri, Dharmendra Kumar; Juvekar, Archana Ramesh

    2016-01-01

    Background: Curcumin and ellagic are the natural polyphenols having a wide range of pharmacological actions. They have been reported to have their use in various neurological disorders. Objective: This study was aimed to evaluate the effect of curcumin and ellagic acid on the activity of monoamine oxidase (MAO), the enzyme responsible for metabolism of monoamine neurotransmitters which are pivotal for neuronal development and function. Materials and Methods: The in vitro effects of these selected polyphenols on MAO activities in mitochondria isolated from rat brains were examined. Brain mitochondria were assayed for MAO type-B (MAO-B) using benzylamine as substrates. Rat brain mitochondrial MAO preparation was used to study the kinetics of enzyme inhibition using double reciprocal Lineweaver–Burk plot. Results: MAO activity was inhibited by curcumin and ellagic acid; however, higher half maximal inhibitory concentrations of curcumin (500.46 nM) and ellagic acid (412.24 nM) were required compared to the known MAO-B inhibitor selegiline. It is observed that the curcumin and ellagic acid inhibit the MAO activity with both the competitive and noncompetitive type of inhibitions. Conclusions: Curcumin and ellagic acid can be considered a possible source of MAO inhibitor used in the treatment of Parkinson's and other neurological disorders. SUMMARY Monoamine oxidase (MAO) is involved in a variety of neurological disorders including Parkinson's disease (PD)Curcumin and ellagic acid inhibit the monoamine oxidase activityEllagic acid revealed more potent MAO type-B (MAO-B) inhibitory activity than curcuminKinetic studies of MAO inhibition using different concentrations of curcumin and ellagic acid were plotted as double reciprocal Lineweaver–Burk plotThe mode of inhibition of both compounds toward MAO-B is mixed (competitive and uncompetitive) type of inhibition with both the competitive and noncompetitive type of inhibitions. Abbreviations used: MAO: Monoamine oxidase

  16. Corrosion inhibition of a mild steel by aniline and alkylamines in acidic solutions

    SciTech Connect

    Luo, H.; Han, K.N.; Guan, Y.C.

    1998-09-01

    Corrosion inhibition of a mild steel in acid solutions by alkylamines (ALK-AM) and aniline hydrochloric (ANL-HCl) salts was investigated in the presence of sodium sulfate (Na{sub 2}SO{sub 4}) and sodium chloride (NaCl) using a potentiostat, a contact-angle goniometer, a scanning electron microscope (SEM), a Fourier transform infrared spectrometer (FTIR), and an atomic force microscope (AFM). Results showed chloride ions (Cl{sup {minus}}) had a pronounced effect on inhibition of amines and ANL for corrosion of mild steel. In the presence of Cl{sup {minus}} ions, cationic types of surfactants (ALK-AM and ANL) were attached to the surface through formation of chloride precipitate at the surface. In the absence of the organic inhibitors, corrosion initiated along grain boundaries of ferrite and pearlite structures. In the presence of the organic inhibitor, however, the steel surface was covered by an organic salt precipitation, and the corrosion rate was reduced significantly.

  17. The effect of thiobarbituric acid on tyrosinase: inhibition kinetics and computational simulation.

    PubMed

    Yin, Shang-Jun; Si, Yue-Xiu; Wang, Zhi-Jiang; Wang, Su-Fang; Oh, Sangho; Lee, Sanghyuk; Sim, Seon-Mi; Yang, Jun-Mo; Qian, Guo-Ying; Lee, Jinhyuk; Park, Yong-Doo

    2011-12-01

    Tyrosinase plays various roles in organisms and much research has focused on the regulation of tyrosinase activity. We studied the inhibitory effect of thiobarbituric acid (TBA) on tyrosinase. Our kinetic study showed that TBA inhibited tyrosinase in a reversible noncompetitive manner (K(i) 5 14.0 ± 8.5 mM and IC₅₀ 5 8.0 ± 1.0 mM). Intrinsic and ANS-binding fluorescences studies were also performed to gain more information regarding the binding mechanism. The results showed that no tertiary structural changes were obviously observed. For further insight, we predicted the 3D structure of tyrosinase and simulated the docking between tyrosinase and TBA. The docking simulation was successful with significant scores (binding energy for AutoDock4: -5.52 kcal/mol) and suggested that TBA was located in the active site. The 11 ns molecular dynamics simulation convinced that the four HIS residues (residue numbers: 57, 90, 250, and 282) were commonly responsible for the interaction with TBA. Our results provide a new inhibition strategy that works using an antioxidant rather than targeting the copper ions within the tyrosinase active site. PMID:22066533

  18. Changes in oxidation reduction potentials and volatile fatty acid production by rumen bacteria when methane synthesis is inhibited.

    PubMed

    Sauer, F D; Teather, R M

    1987-09-01

    Rumen inoculum was cultured in specially designed fermenters that allowed simultaneous measurement of pH, oxidation-reduction potentials, and gas production. The cultures were maintained at pH 6.8 by addition of 1 M NaHCO3 and continuous infusion of artificial saliva. Gas flow was maintained at 20.0 ml/min with a stream of O2-free N2. Monensin at 7.0 micrograms/ml inhibited CH4 production 49% below control concentrations. The sodium salt of 2-bromoethanesulfonic acid added at an initial concentration of 5 x 10(-5) M inhibited CH4 production by 86% and increased H2 production from less than .5 mumol/min in the control to 24.5 mumol/min in the inhibited fermenter. The redox potentials in the control fermenter remained above -.20 V and did not change with the addition of monensin. Bromoethanesulfonic acid rapidly decreased the redox potential in the fermenter to -.33 V. Volatile fatty acid production was not significantly altered by the addition of 2-bromoethanesulfonic acid. The addition of monensin gave the expected decrease in acetate:propionate ratios, decreased acetate and butyrate production, and increased valerate (but not propionate) production.

  19. Comparison of sodium acid sulfate to citric acid to inhibit browning of fresh-cut potatoes.

    PubMed

    Calder, Beth L; Kash, Emily A; Davis-Dentici, Katherine; Bushway, Alfred A

    2011-04-01

    Sodium acid sulfate (SAS) dip treatments were evaluated against a distilled water control and citric acid (CA) to compare its effectiveness in reducing enzymatic browning of raw, French-fry cut potatoes. Two separate studies were conducted with dip concentrations ranging from 0%, 1%, and 3% in experiment 1 to 0%, 2%, and 2.5% in experiment 2 to determine optimal dip concentrations. Russet Burbank potatoes were peeled, sliced, and dipped for 1 min and stored at 3 °C. Color, texture, fry surface pH, and microbiological analyses were conducted on days 0, 7, and 14. The 3% SAS- and CA-treated samples had significantly (p<0.0001) lower pH levels on fry surfaces than all other treatments. Both acidulants had significantly (p≤0.05) lower aerobic plate counts compared to controls in both studies by day 7. However, SAS appeared to be the most effective at the 3% level in maintaining a light fry color up to day 14 and had the highest L-values than all other treatments. The 3% SAS-treated fry slices appeared to have the least change in textural properties over storage time, having a significantly (p=0.0002) higher force value (kg force [kgf]) than the other treatments during experiment 1, without any signs of case-hardening that appeared in the control and CA-treated samples. SAS was just as comparable to CA in reducing surface fry pH and also lowering microbial counts over storage time. According to the results, SAS may be another viable acidulant to be utilized in the fresh-cut fruit and vegetable industry.

  20. HDAC Inhibition Modulates Cardiac PPARs and Fatty Acid Metabolism in Diabetic Cardiomyopathy

    PubMed Central

    Lee, Ting-I; Tsai, Wen-Chin; Chung, Cheng-Chih; Chen, Yao-Chang; Chen, Yi-Jen

    2016-01-01

    Peroxisome proliferator-activated receptors (PPARs) regulate cardiac glucose and lipid homeostasis. Histone deacetylase (HDAC) inhibitor has anti-inflammatory effects which may play a key role in modulating PPARs and fatty acid metabolism. The aim of this study was to investigate whether HDAC inhibitor, MPT0E014, can modulate myocardial PPARs, inflammation, and fatty acid metabolism in diabetes mellitus (DM) cardiomyopathy. Electrocardiography, echocardiography, and western blotting were used to evaluate the electrophysiological activity, cardiac structure, fatty acid metabolism, inflammation, and PPAR isoform expressions in the control and streptozotocin-nicotinamide-induced DM rats with or without MPT0E014. Compared to control, DM and MPT0E014-treated DM rats had elevated blood glucose levels and lower body weights. However, MPT0E014-treated DM and control rats had smaller left ventricular end-diastolic diameter and shorter QT interval than DM rats. The control and MPT0E014-treated DM rats had greater cardiac PPAR-α and PPAR-δ protein expressions, but less cardiac PPAR-γ than DM rats. Moreover, control and MPT0E014-treated DM rats had lower concentrations of 5′ adenosine monophosphate-activated protein kinase 2α, PPAR-γ coactivator 1α, phosphorylated acetyl CoA carboxylase, cluster of differentiation 36, diacylglycerol acyltransferase 1 (DGAT1), DGAT2, tumor necrosis factor-α, and interleukin-6 protein than DM rats. HDAC inhibition significantly attenuated DM cardiomyopathy through modulation of cardiac PPARS, fatty acid metabolism, and proinflammatory cytokines. PMID:27446205

  1. Eicosopentaneoic Acid and Other Free Fatty Acid Receptor Agonists Inhibit Lysophosphatidic Acid- and Epidermal Growth Factor-Induced Proliferation of Human Breast Cancer Cells

    PubMed Central

    Hopkins, Mandi M.; Zhang, Zhihong; Liu, Ze; Meier, Kathryn E.

    2016-01-01

    Many key actions of ω-3 (n-3) fatty acids have recently been shown to be mediated by two G protein-coupled receptors (GPCRs) in the free fatty acid receptor (FFAR) family, FFA1 (GPR40) and FFA4 (GPR120). n-3 Fatty acids inhibit proliferation of human breast cancer cells in culture and in animals. In the current study, the roles of FFA1 and FFA4 were investigated. In addition, the role of cross-talk between GPCRs activated by lysophosphatidic acid (LPA), and the tyrosine kinase receptor activated by epidermal growth factor (EGF), was examined. In MCF-7 and MDA-MB-231 human breast cancer cell lines, both LPA and EGF stimulated proliferation, Erk activation, Akt activation, and CCN1 induction. LPA antagonists blocked effects of LPA and EGF on proliferation in MCF-7 and MDA-MB-231, and on cell migration in MCF-7. The n-3 fatty acid eicosopentaneoic acid inhibited LPA- and EGF-induced proliferation in both cell lines. Two synthetic FFAR agonists, GW9508 and TUG-891, likewise inhibited LPA- and EGF-induced proliferation. The data suggest a major role for FFA1, which was expressed by both cell lines. The results indicate that n-3 fatty acids inhibit breast cancer cell proliferation via FFARs, and suggest a mechanism involving negative cross-talk between FFARS, LPA receptors, and EGF receptor. PMID:26821052

  2. Transformation with Oncogenic Ras and the Simian Virus 40 T Antigens Induces Caspase-Dependent Sensitivity to Fatty Acid Biosynthetic Inhibition

    PubMed Central

    Xu, Shihao; Spencer, Cody M.

    2015-01-01

    ABSTRACT Oncogenesis is frequently accompanied by the activation of specific metabolic pathways. One such pathway is fatty acid biosynthesis, whose induction is observed upon transformation of a wide variety of cell types. Here, we explored how defined oncogenic alleles, specifically the simian virus 40 (SV40) T antigens and oncogenic Ras12V, affect fatty acid metabolism. Our results indicate that SV40/Ras12V-mediated transformation of fibroblasts induces fatty acid biosynthesis in the absence of significant changes in the concentration of fatty acid biosynthetic enzymes. This oncogene-induced activation of fatty acid biosynthesis was found to be mammalian target of rapamycin (mTOR) dependent, as it was attenuated by rapamycin treatment. Furthermore, SV40/Ras12V-mediated transformation induced sensitivity to treatment with fatty acid biosynthetic inhibitors. Pharmaceutical inhibition of acetyl-coenzyme A (CoA) carboxylase (ACC), a key fatty acid biosynthetic enzyme, induced caspase-dependent cell death in oncogene-transduced cells. In contrast, isogenic nontransformed cells were resistant to fatty acid biosynthetic inhibition. This oncogene-induced sensitivity to fatty acid biosynthetic inhibition was independent of the cells' growth rates and could be attenuated by supplementing the medium with unsaturated fatty acids. Both the activation of fatty acid biosynthesis and the sensitivity to fatty acid biosynthetic inhibition could be conveyed to nontransformed breast epithelial cells through transduction with oncogenic Ras12V. Similar to what was observed in the transformed fibroblasts, the Ras12V-induced sensitivity to fatty acid biosynthetic inhibition was independent of the proliferative status and could be attenuated by supplementing the medium with unsaturated fatty acids. Combined, our results indicate that specific oncogenic alleles can directly confer sensitivity to inhibitors of fatty acid biosynthesis. IMPORTANCE Viral oncoproteins and cellular mutations

  3. Plant Food Delphinidin-3-Glucoside Significantly Inhibits Platelet Activation and Thrombosis: Novel Protective Roles against Cardiovascular Diseases

    PubMed Central

    Yang, Yan; Shi, Zhenyin; Reheman, Adili; Jin, Joseph W.; Li, Conglei; Wang, Yiming; Andrews, Marc C.; Chen, Pingguo; Zhu, Guangheng; Ling, Wenhua; Ni, Heyu

    2012-01-01

    Delphinidin-3-glucoside (Dp-3-g) is one of the predominant bioactive compounds of anthocyanins in many plant foods. Although several anthocyanin compounds have been reported to be protective against cardiovascular diseases (CVDs), the direct effect of anthocyanins on platelets, the key players in atherothrombosis, has not been studied. The roles of Dp-3-g in platelet function are completely unknown. The present study investigated the effects of Dp-3-g on platelet activation and several thrombosis models in vitro and in vivo. We found that Dp-3-g significantly inhibited human and murine platelet aggregation in both platelet-rich plasma and purified platelets. It also markedly reduced thrombus growth in human and murine blood in perfusion chambers at both low and high shear rates. Using intravital microscopy, we observed that Dp-3-g decreased platelet deposition, destabilized thrombi, and prolonged the time required for vessel occlusion. Dp-3-g also significantly inhibited thrombus growth in a carotid artery thrombosis model. To elucidate the mechanisms, we examined platelet activation markers via flow cytometry and found that Dp-3-g significantly inhibited the expression of P-selectin, CD63, CD40L, which reflect platelet α- and δ-granule release, and cytosol protein secretion, respectively. We further demonstrated that Dp-3-g downregulated the expression of active integrin αIIbβ3 on platelets, and attenuated fibrinogen binding to platelets following agonist treatment, without interfering with the direct interaction between fibrinogen and integrin αIIbβ3. We found that Dp-3-g reduced phosphorylation of adenosine monophosphate-activated protein kinase, which may contribute to the observed inhibitory effects on platelet activation. Thus, Dp-3-g significantly inhibits platelet activation and attenuates thrombus growth at both arterial and venous shear stresses, which likely contributes to its protective roles against thrombosis and CVDs. PMID:22624015

  4. Tormentic acid inhibits H2O2-induced oxidative stress and inflammation in rat vascular smooth muscle cells via inhibition of the NF-κB signaling pathway.

    PubMed

    Wang, Yu-Lun; Sun, Gen-Yi; Zhang, Ying; He, Jia-Jun; Zheng, Shen; Lin, Jing-Na

    2016-10-01

    Tormentic acid (TA) is a triterpene isolated from the stem bark of the plant Vochysia divergens and has been reported to exhibit anticancer, anti‑inflammatory and anti‑atherogenic properties. However, the functions of TA in hydrogen peroxide (H2O2)‑induced oxidative stress and inflammation in rat vascular smooth muscle cells (RVSMCs) remain unclear. Therefore, the present study aimed to investigate whether TA suppressed H2O2‑induced oxidative stress and inflammation in RVSMCs, and to determine its molecular mechanisms. The present study demonstrated that TA inhibited reactive oxygen species (ROS) generation, induced H2O2 in RVSMCs, and inhibited H2O2-induced expression of inducible nitric oxide synthase (iNOS) and NADPH oxidase (NOX) in RVSMCs. In addition, TA significantly decreased the production of tumor necrosis factor‑α (TNF‑α), interleukin 6 (IL‑6) and IL‑1β. Furthermore, TA pretreatment prevented nuclear factor‑κB (NF‑κB) subunit p65 phosphorylation and NF‑κB inhibitor α (IκBα) degradation induced by H2O2 in RVSMCs. TA is, therefore, suggested to inhibit H2O2-induced oxidative stress and inflammation in RVSMCs via inhibition of the NF‑κB signaling pathway. TA may have potential as a pharmacological agent in the prevention or treatment of atherosclerosis. PMID:27572426

  5. Tormentic acid inhibits H2O2-induced oxidative stress and inflammation in rat vascular smooth muscle cells via inhibition of the NF-κB signaling pathway

    PubMed Central

    Wang, Yu-Lun; Sun, Gen-Yi; Zhang, Ying; He, Jia-Jun; Zheng, Shen; Lin, Jing-Na

    2016-01-01

    Tormentic acid (TA) is a triterpene isolated from the stem bark of the plant Vochysia divergens and has been reported to exhibit anticancer, anti-inflammatory and anti-atherogenic properties. However, the functions of TA in hydrogen peroxide (H2O2)-induced oxidative stress and inflammation in rat vascular smooth muscle cells (RVSMCs) remain unclear. Therefore, the present study aimed to investigate whether TA suppressed H2O2-induced oxidative stress and inflammation in RVSMCs, and to determine its molecular mechanisms. The present study demonstrated that TA inhibited reactive oxygen species (ROS) generation, induced H2O2 in RVSMCs, and inhibited H2O2-induced expression of inducible nitric oxide synthase (iNOS) and NADPH oxidase (NOX) in RVSMCs. In addition, TA significantly decreased the production of tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6) and IL-1β. Furthermore, TA pretreatment prevented nuclear factor-κB (NF-κB) subunit p65 phosphorylation and NF-κB inhibitor α (IκBα) degradation induced by H2O2 in RVSMCs. TA is, therefore, suggested to inhibit H2O2-induced oxidative stress and inflammation in RVSMCs via inhibition of the NF-κB signaling pathway. TA may have potential as a pharmacological agent in the prevention or treatment of atherosclerosis. PMID:27572426

  6. Tormentic acid inhibits H2O2-induced oxidative stress and inflammation in rat vascular smooth muscle cells via inhibition of the NF-κB signaling pathway.

    PubMed

    Wang, Yu-Lun; Sun, Gen-Yi; Zhang, Ying; He, Jia-Jun; Zheng, Shen; Lin, Jing-Na

    2016-10-01

    Tormentic acid (TA) is a triterpene isolated from the stem bark of the plant Vochysia divergens and has been reported to exhibit anticancer, anti‑inflammatory and anti‑atherogenic properties. However, the functions of TA in hydrogen peroxide (H2O2)‑induced oxidative stress and inflammation in rat vascular smooth muscle cells (RVSMCs) remain unclear. Therefore, the present study aimed to investigate whether TA suppressed H2O2‑induced oxidative stress and inflammation in RVSMCs, and to determine its molecular mechanisms. The present study demonstrated that TA inhibited reactive oxygen species (ROS) generation, induced H2O2 in RVSMCs, and inhibited H2O2-induced expression of inducible nitric oxide synthase (iNOS) and NADPH oxidase (NOX) in RVSMCs. In addition, TA significantly decreased the production of tumor necrosis factor‑α (TNF‑α), interleukin 6 (IL‑6) and IL‑1β. Furthermore, TA pretreatment prevented nuclear factor‑κB (NF‑κB) subunit p65 phosphorylation and NF‑κB inhibitor α (IκBα) degradation induced by H2O2 in RVSMCs. TA is, therefore, suggested to inhibit H2O2-induced oxidative stress and inflammation in RVSMCs via inhibition of the NF‑κB signaling pathway. TA may have potential as a pharmacological agent in the prevention or treatment of atherosclerosis.

  7. The SCFA butyrate stimulates the epithelial production of retinoic acid via inhibition of epithelial HDAC.

    PubMed

    Schilderink, Ronald; Verseijden, Caroline; Seppen, Jurgen; Muncan, Vanesa; van den Brink, Gijs R; Lambers, Tim T; van Tol, Eric A; de Jonge, Wouter J

    2016-06-01

    In the intestinal mucosa, retinoic acid (RA) is a critical signaling molecule. RA is derived from dietary vitamin A (retinol) through conversion by aldehyde dehydrogenases (aldh). Reduced levels of short-chain fatty acids (SCFAs) are associated with pathological microbial dysbiosis, inflammatory disease, and allergy. We hypothesized that SCFAs contribute to mucosal homeostasis by enhancing RA production in intestinal epithelia. With the use of human and mouse epithelial cell lines and primary enteroids, we studied the effect of SCFAs on the production of RA. Functional RA conversion was analyzed by Adlefluor activity assays. Butyrate (0-20 mM), in contrast to other SCFAs, dose dependently induced aldh1a1 or aldh1a3 transcript expression and increased RA conversion in human and mouse epithelial cells. Epithelial cell line data were replicated in intestinal organoids. In these organoids, butyrate (2-5 mM) upregulated aldh1a3 expression (36-fold over control), whereas aldh1a1 was not significantly affected. Butyrate enhanced maturation markers (Mucin-2 and villin) but did not consistently affect stemness markers or other Wnt target genes (lgr5, olfm4, ascl2, cdkn1). In enteroids, the stimulation of RA production by SCFA was mimicked by inhibitors of histone deacetylase 3 (HDAC3) but not by HDAC1/2 inhibitors nor by agonists of butyrate receptors G-protein-coupled receptor (GPR)43 or GPR109A, indicating that butyrate stimulates RA production via HDAC3 inhibition. We conclude that the SCFA butyrate inhibits HDAC3 and thereby supports epithelial RA production. PMID:27151945

  8. Full Fatty Acid Amide Hydrolase Inhibition Combined with Partial Monoacylglycerol Lipase Inhibition: Augmented and Sustained Antinociceptive Effects with Reduced Cannabimimetic Side Effects in Mice

    PubMed Central

    Ghosh, Sudeshna; Kinsey, Steven G.; Liu, Qing-song; Hruba, Lenka; McMahon, Lance R.; Grim, Travis W.; Merritt, Christina R.; Wise, Laura E.; Abdullah, Rehab A.; Selley, Dana E.; Sim-Selley, Laura J.; Cravatt, Benjamin F.

    2015-01-01

    Inhibition of fatty acid amide hydrolase (FAAH) or monoacylglycerol lipase (MAGL), the primary hydrolytic enzymes for the respective endocannabinoids N-arachidonoylethanolamine (AEA) and 2-arachidonylglycerol (2-AG), produces antinociception but with minimal cannabimimetic side effects. Although selective inhibitors of either enzyme often show partial efficacy in various nociceptive models, their combined blockade elicits augmented antinociceptive effects, but side effects emerge. Moreover, complete and prolonged MAGL blockade leads to cannabinoid receptor type 1 (CB1) receptor functional tolerance, which represents another challenge in this potential therapeutic strategy. Therefore, the present study tested whether full FAAH inhibition combined with partial MAGL inhibition would produce sustained antinociceptive effects with minimal cannabimimetic side effects. Accordingly, we tested a high dose of the FAAH inhibitor PF-3845 (N-​3-​pyridinyl-​4-​[[3-​[[5-​(trifluoromethyl)-​2-​pyridinyl]oxy]phenyl]methyl]-​1-​piperidinecarboxamide; 10 mg/kg) given in combination with a low dose of the MAGL inhibitor JZL184 [4-nitrophenyl 4-(dibenzo[d][1,3]dioxol-5-yl(hydroxy)methyl)piperidine-1-carboxylate] (4 mg/kg) in mouse models of inflammatory and neuropathic pain. This combination of inhibitors elicited profound increases in brain AEA levels (>10-fold) but only 2- to 3-fold increases in brain 2-AG levels. This combination produced significantly greater antinociceptive effects than single enzyme inhibition and did not elicit common cannabimimetic effects (e.g., catalepsy, hypomotility, hypothermia, and substitution for Δ9-tetrahydrocannabinol in the drug-discrimination assay), although these side effects emerged with high-dose JZL184 (i.e., 100 mg/kg). Finally, repeated administration of this combination did not lead to tolerance to its antiallodynic actions in the carrageenan assay or CB1 receptor functional tolerance. Thus, full FAAH inhibition combined

  9. Full Fatty Acid Amide Hydrolase Inhibition Combined with Partial Monoacylglycerol Lipase Inhibition: Augmented and Sustained Antinociceptive Effects with Reduced Cannabimimetic Side Effects in Mice.

    PubMed

    Ghosh, Sudeshna; Kinsey, Steven G; Liu, Qing-Song; Hruba, Lenka; McMahon, Lance R; Grim, Travis W; Merritt, Christina R; Wise, Laura E; Abdullah, Rehab A; Selley, Dana E; Sim-Selley, Laura J; Cravatt, Benjamin F; Lichtman, Aron H

    2015-08-01

    Inhibition of fatty acid amide hydrolase (FAAH) or monoacylglycerol lipase (MAGL), the primary hydrolytic enzymes for the respective endocannabinoids N-arachidonoylethanolamine (AEA) and 2-arachidonylglycerol (2-AG), produces antinociception but with minimal cannabimimetic side effects. Although selective inhibitors of either enzyme often show partial efficacy in various nociceptive models, their combined blockade elicits augmented antinociceptive effects, but side effects emerge. Moreover, complete and prolonged MAGL blockade leads to cannabinoid receptor type 1 (CB1) receptor functional tolerance, which represents another challenge in this potential therapeutic strategy. Therefore, the present study tested whether full FAAH inhibition combined with partial MAGL inhibition would produce sustained antinociceptive effects with minimal cannabimimetic side effects. Accordingly, we tested a high dose of the FAAH inhibitor PF-3845 (N-​3-​pyridinyl-​4-​[[3-​[[5-​(trifluoromethyl)-​2-​pyridinyl]oxy]phenyl]methyl]-​1-​piperidinecarboxamide; 10 mg/kg) given in combination with a low dose of the MAGL inhibitor JZL184 [4-nitrophenyl 4-(dibenzo[d][1,3]dioxol-5-yl(hydroxy)methyl)piperidine-1-carboxylate] (4 mg/kg) in mouse models of inflammatory and neuropathic pain. This combination of inhibitors elicited profound increases in brain AEA levels (>10-fold) but only 2- to 3-fold increases in brain 2-AG levels. This combination produced significantly greater antinociceptive effects than single enzyme inhibition and did not elicit common cannabimimetic effects (e.g., catalepsy, hypomotility, hypothermia, and substitution for Δ(9)-tetrahydrocannabinol in the drug-discrimination assay), although these side effects emerged with high-dose JZL184 (i.e., 100 mg/kg). Finally, repeated administration of this combination did not lead to tolerance to its antiallodynic actions in the carrageenan assay or CB1 receptor functional tolerance. Thus, full FAAH inhibition

  10. Inhibition of release of taurine and excitatory amino acids in ischemia and neuroprotection.

    PubMed

    Kimelberg, Harold K; Nestor, Nestor B; Feustel, Paul J

    2004-01-01

    Volume regulated anion channels (VRAC) have been extensively studied in purified single cell systems like cell cultures where they can be activated by cell swelling. This provides a convenient way of analyzing mechanisms and will likely lead to the holy grails of the field, namely the nature or natures of the volume sensor and the nature or natures of VRACs. Important reasons for such an understanding are that these channels are ubiquitous and have important physiological functions which under pathological conditions convert to deleterious effects. Here we summarize data showing the involvement of VRACs in ischemia-induced release of excitatory amino acids (EAAs) in a rat model of global ischemia. Using microdialysis studies we found that reversal of the astrocytic glutamate transporter and VRACs contribute about equally to the large initial release of EAAs and together account for around 80% of the total release. We used the very potent VRAC blocker, tamoxifen, to see if such inhibition of EAA release via VRACs led to significant neuroprotection. Treatment in the focal rat MCA occlusion model led to around 80% reduction in infarct size with an effective post initiation of ischemia therapeutic window of three hours. However, the common problem of other effects for even the most potent inhibitors pertains here, as tamoxifen has other, potentially neuroprotective, effects. Thus it inhibits nitrotyrosine formation, likely due to its inhibition of nNOS and reduction of peroxynitrite formation. Although tamoxifen cannot therefore be used as a test of the "VRAC-excitotxicity" hypothesis it may prove successful for translation of basic stroke research to the clinic because of its multiple targets.

  11. Inhibition of corneal neovascularization with a nutrient mixture containing lysine, proline, ascorbic acid, and green tea extract.

    PubMed

    Shakiba, Yadollah; Mostafaie, Ali

    2007-10-01

    Corneal neovascularization is a significant, sight-threatening complication of many ocular surface disorders. Various growth factors and proteinases are involved in corneal neovascularization. The data supporting a causal role for vascular endothelial growth factor (VEGF) and matrix metalloproteinases (MMPs) are extensive. Inhibition of VEGF and MMPs is a main strategy for treating corneal neovascularization. Several findings have shown that corneal neovascularization can be reduced by using anti-VEGF and anti-MMPs agents. Efficacy of a nutrient mixture (NM) containing lysine, proline, ascorbic acid, and green tea extract has been demonstrated for reducing VEGF and MMPs secretion by various cells. Moreover, NM can inhibit endothelial cell migration and capillary tube formation. We herein note that topical application of NM is potentially useful for inhibiting corneal neovascularization and restoration of corneal clarity. Further investigations in animal models are needed to place NM alongside corneal neovascularization therapeutics.

  12. Mechanism of fusidic acid inhibition of RRF- and EF-G-dependent splitting of the bacterial post-termination ribosome

    PubMed Central

    Borg, Anneli; Pavlov, Michael; Ehrenberg, Måns

    2016-01-01

    The antibiotic drug fusidic acid (FA) is commonly used in the clinic against gram-positive bacterial infections. FA targets ribosome-bound elongation factor G (EF-G), a translational GTPase that accelerates both messenger RNA (mRNA) translocation and ribosome recycling. How FA inhibits translocation was recently clarified, but FA inhibition of ribosome recycling by EF-G and ribosome recycling factor (RRF) has remained obscure. Here we use fast kinetics techniques to estimate mean times of ribosome splitting and the stoichiometry of GTP hydrolysis by EF-G at varying concentrations of FA, EF-G and RRF. These mean times together with previous data on uninhibited ribosome recycling were used to clarify the mechanism of FA inhibition of ribosome splitting. The biochemical data on FA inhibition of translocation and recycling were used to model the growth inhibitory effect of FA on bacterial populations. We conclude that FA inhibition of translocation provides the dominant cause of bacterial growth reduction, but that FA inhibition of ribosome recycling may contribute significantly to FA-induced expression of short regulatory open reading frames, like those involved in FA resistance. PMID:27001509

  13. Mechanism of fusidic acid inhibition of RRF- and EF-G-dependent splitting of the bacterial post-termination ribosome.

    PubMed

    Borg, Anneli; Pavlov, Michael; Ehrenberg, Måns

    2016-04-20

    The antibiotic drug fusidic acid (FA) is commonly used in the clinic against gram-positive bacterial infections. FA targets ribosome-bound elongation factor G (EF-G), a translational GTPase that accelerates both messenger RNA (mRNA) translocation and ribosome recycling. How FA inhibits translocation was recently clarified, but FA inhibition of ribosome recycling by EF-G and ribosome recycling factor (RRF) has remained obscure. Here we use fast kinetics techniques to estimate mean times of ribosome splitting and the stoichiometry of GTP hydrolysis by EF-G at varying concentrations of FA, EF-G and RRF. These mean times together with previous data on uninhibited ribosome recycling were used to clarify the mechanism of FA inhibition of ribosome splitting. The biochemical data on FA inhibition of translocation and recycling were used to model the growth inhibitory effect of FA on bacterial populations. We conclude that FA inhibition of translocation provides the dominant cause of bacterial growth reduction, but that FA inhibition of ribosome recycling may contribute significantly to FA-induced expression of short regulatory open reading frames, like those involved in FA resistance. PMID:27001509

  14. Inhibition of multiplication of the prototypic arenavirus LCMV by valproic acid

    PubMed Central

    Vázquez-Calvo, Ángela; Martín-Acebes, Miguel A.; Sáiz, Juan-Carlos; Ngo, Nhi; Sobrino, F.; de la Torre, Juan Carlos

    2013-01-01

    Valproic acid (VPA), a short chain fatty acid commonly used for treatment of neurological disorders, has been shown to inhibit production of infectious progeny of different enveloped viruses including the prototypic arenavirus lymphocytic choriomeningitis virus (LCMV). In this study we have investigated the mechanisms by which VPA inhibits LCMV multiplication in cultured cells. VPA reduced production of infectious LCMV progeny and virus propagation without exerting a major blockage on either viral RNA or protein synthesis, but rather affecting the cell release and specific infectivity of LCMV progeny from infected cells. Our results would support the repurposing of VPA as a candidate antiviral drug to combat arenavirus infections. PMID:23735299

  15. Crystal structure of the thioesterase domain of human fatty acid synthase inhibited by orlistat

    SciTech Connect

    Pemble,C.; Johnson, L.; Kridel, S.; Lowther, W.

    2007-01-01

    Human fatty acid synthase (FAS) is uniquely expressed at high levels in many tumor types. Pharmacological inhibition of FAS therefore represents an important therapeutic opportunity. The drug Orlistat, which has been approved by the US Food and Drug Administration, inhibits FAS, induces tumor cell-specific apoptosis and inhibits the growth of prostate tumor xenografts. We determined the 2.3-{angstrom}-resolution crystal structure of the thioesterase domain of FAS inhibited by Orlistat. Orlistat was captured in the active sites of two thioesterase molecules as a stable acyl-enzyme intermediate and as the hydrolyzed product. The details of these interactions reveal the molecular basis for inhibition and suggest a mechanism for acyl-chain length discrimination during the FAS catalytic cycle. Our findings provide a foundation for the development of new cancer drugs that target FAS.

  16. Effects of PI3K inhibition and low docosahexaenoic acid on cognition and behavior.

    PubMed

    Bandaru, Sathyajit S; Lin, Kristen; Roming, Stephanie L; Vellipuram, Ramana; Harney, Jacob P

    2010-06-01

    Alterations in two components of the brain's insulin signaling pathway, docosahexaenoic acid (DHA) content and phosphoinositide 3-kinase (PI3K) activity, have been implicated in the insulin resistance that is central to type II diabetes mellitus (DM). A 2- to 3-fold increased risk of developing Alzheimer's disease (AD) in patients with type II DM suggests a potential link between cognition and insulin action. The current study was designed to examine the impact of DHA dietary content and PI3K activity on learning, memory, depression, and anxiety in rodents. Mice were divided into the following groups: (1) control diet and vehicle injection (control PI3K), (2) control diet and wortmannin injection (PI3K inhibition), (3) low DHA diet and vehicle, and (4) low DHA diet and wortmannin. Each group was assessed for effects on activity, cognition, depression, and anxiety. Concentrations of glucose and insulin in plasma were quantified to confirm insulin resistance. Results showed significant increases in depression, anxiety, plasma insulin and glucose, and significant decreases in activity in wortmannin-treated mice regardless of diet. The control diet/wortmannin-treated group showed a significant decrease in memory compared to all other groups. The low DHA diet/wortmannin-treated group had slightly improved memory and lower levels of depression compared to the control diet/wortmannin-treated group. Results of the present study suggest that inhibition of PI3K decreases activity and memory while increasing insulin resistance, depression, and anxiety. In addition, these results suggest a possible compensatory role of low DHA in decreasing the effects of dysfunctional PI3K in AD associated cognitive decline and depression. PMID:19914265

  17. Restoration of Brain Acid Soluble Protein 1 Inhibits Proliferation and Migration of Thyroid Cancer Cells

    PubMed Central

    Guo, Run-Sheng; Yu, Yue; Chen, Jun; Chen, Yue-Yu; Shen, Na; Qiu, Ming

    2016-01-01

    Background: Brain acid soluble protein 1 (BASP1) is identified as a novel potential tumor suppressor in several cancers. However, its role in thyroid cancer has not been investigated yet. In the present study, the antitumor activities of BASP1 against the growth and migration of thyroid cancer cells were evaluated. Methods: BASP1 expression in thyroid cancer tissues and normal tissues were examined by immunohistochemical staining and the association between its expression and prognosis was analyzed. pcDNA-BASP1 carrying full length of BASP1 cDNA was constructed to restore the expression of BASP1 in thyroid cancer cell lines (BHT-101 and KMH-2). The cell proliferation in vitro and in vivo was evaluated by WST-1 assay and xenograft tumor models, respectively. Cell cycle distribution after transfection was analyzed using flow cytometry. Cell apoptosis after transfection was examined by annexin V/propidium iodide assay. The migration was examined using transwell assay. Results: BASP1 expression was abundant in normal tissues while it is significantly decreased in cancer tissues (P = 0.000). pcDNA-BASP1 restored the expression of BASP1 and significantly inhibited the growth of BHT-101 and KMH-2 cells as well as xenograft tumors in nude mice (P = 0.000). pcDNA-BASP1 induced G1 arrest and apoptosis in BHT-101 and KMH-2 cells. In addition, pcDNA-BASP1 significantly inhibited the cell migration. Conclusions: Downregulation of BASP1 expression may play a role in the tumorigenesis of thyroid cancer. Restoration of BASP1 expression exerted extensive antitumor activities against growth and migration of thyroid cancer cells, which suggested that BASP1 gene might act as a potential therapeutic agent for the treatment of thyroid cancer. PMID:27270539

  18. Tolfenamic acid inhibits neuroblastoma cell proliferation and induces apoptosis: a novel therapeutic agent for neuroblastoma.

    PubMed

    Eslin, Don; Sankpal, Umesh T; Lee, Chris; Sutphin, Robert M; Maliakal, Pius; Currier, Erika; Sholler, Giselle; Khan, Moeez; Basha, Riyaz

    2013-05-01

    Current therapeutic options for recurrent neuroblastoma have poor outcomes that warrant the development of novel therapeutic strategies. Specificity protein (Sp) transcription factors regulate several genes involved in cell proliferation, survival, and angiogenesis. Sp1 regulates genes believed to be important determinants of the biological behavior of neuroblastoma. Tolfenamic acid (TA), a non-steroidal anti-inflammatory drug, is known to induce the degradation of Sp proteins and may serve as a novel anti-cancer agent. The objective of this investigation was to examine the anti-cancer activity of TA using established human neuroblastoma cell lines. We tested the anti-proliferative effect of TA using SH-SY5Y, CHLA90, LA1 55n, SHEP, Be2c, CMP 13Y, and SMS KCNR cell lines. Cells were treated with TA (0/25/50/100 µM) and cell viability was measured at 24, 48, and 72 h post-treatment. Selected neuroblastoma cell lines were treated with 50 µM TA for 24 and 48 h and tested for cell apoptosis using Annexin-V staining. Caspase activity was measured with caspase 3/7 Glo kit. Cell lysates were prepared and the expression of Sp1, survivin, and c-PARP were evaluated through Western blot analysis. TA significantly inhibited the growth of neuroblastoma cells in a dose/time-dependent manner and significantly decreased Sp1 and survivin expression. Apart from cell cycle (G0/G1) arrest, TA caused significant increase in the apoptotic cell population, caspase 3/7 activity, and c-PARP expression. These results show that TA effectively inhibits neuroblastoma cell growth potentially through suppressing mitosis, Sp1, and survivin expression, and inducing apoptosis. These results show TA as a novel therapeutic agent for neuroblastoma.

  19. Inhibition of arachidonic acid metabolism decreases tumor cell invasion and matrix metalloproteinase expression.

    PubMed

    Koontongkaew, Sittichai; Monthanapisut, Paopanga; Saensuk, Theeranuch

    2010-11-01

    Head and neck cancers are known to synthesize arachidonic acid metabolites. Interfering with arachidonic acid metabolism may inhibit growth and invasiveness of cancer cells. In this study we investigate effects of sulindac (the non-selective COX inhibitor), aspirin (the irreversible, preferential COX-1 inhibitor), NS-398 (the selective COX-2 inhibitor), NDGA (nordihydroguaiaretic acid, the selective LOX inhibitor) and ETYA (5,8,11,14-eicosatetraynoic acid, the COX and LOX inhibitor) on cell viability, MMP-2 and MMP-9 activities, and in vitro invasion of cancer cells derived from primary and metastatic head and neck, and colon cancers. The inhibitors of COX and/or LOX could inhibit cell proliferation, MMP activity and invasion in head and neck and colon cancer cells. However, the inhibitory effect was obviously observed in colon cancer cells. Inhibition of arachidonic acid metabolism caused a decrease in cancer cell motility, which partially explained by the inhibition of MMPs. Therefore, COX and LOX pathways play important roles in head and neck cancer cell growth. PMID:20654727

  20. Apoptosis in barley aleurone during germination and its inhibition by abscisic acid.

    PubMed

    Wang, M; Oppedijk, B J; Lu, X; Van Duijn, B; Schilperoort, R A

    1996-12-01

    During germination of barley grains, DNA fragmentation was observed in the aleurone. The appearance of DNA fragmentation in the aleurone layer, observed by TUNEL staining in aleurone sections, started near the embryo and extended to the aleurone cells far from the embryo in a time dependent manner. The same spatial temporal activities of hydrolytic enzymes such as alpha-amylase were observed in aleurone. DNA fragmentation could also be seen in vitro under osmotic stress, in isolated aleurone. During aleurone protoplast isolation, a very enhanced and strong DNA fragmentation occurred which was not seen in protoplast preparations of tobacco leaves. ABA was found to inhibit DNA fragmentation occurring in barley aleurone under osmotic stress condition and during protoplast isolation, while the plant growth regulator gibberellic acid counteracted the effect of ABA. Addition of auxin or cytokinin had no significant effect on DNA fragmentation in these cells. To study the role of phosphorylation in ABA signal transduction leading to control of DNA fragmentation (apoptosis), the effects of the phosphatase inhibitor okadaic acid and of phenylarisine oxide on apoptosis were studied. We hypothesize that the regulation of DNA fragmentation in aleurone plays a very important role in spatial and temporal control of aleurone activities during germination. The possible signal transduction pathway of ABA leading to the regulation of DNA fragmentation is discussed.

  1. Protease Inhibition by Oleic Acid Transfer From Chronic Wound Dressings to Albumin

    SciTech Connect

    Edwards, J. V.; Howley, Phyllis; Davis, Rachel M.; Mashchak, Andrew D.; Goheen, Steven C.

    2007-08-01

    High elastase and cathepsin G activities have been observed in chronic wounds. These levels can inhibit healing through degradation of growth factors, cytokines, and extracellular matrix proteins. Oleic acid (18:1) is a non-toxic elastase inhibitor with some potential for redressing the imbalance of elastase activity found in chronic wounds. Cotton wound dressing material was characterized as a transfer carrier for affinity uptake of 18:1 by albumin under conditions mimicking chronic wounds. 18:1-treated cotton was examined for its ability to bind and release the fatty acid in the presence of albumin. The mechanism of 18:1 uptake from cotton and binding by albumin was examined with both intact dressings and cotton fiber-designed chromatography. Raman spectra of the albumin-18:1 complexes under liquid-liquid equilibrium conditions revealed fully saturated albumin-18:1 complexes with a 1:1 weight ratio of albumin:18:1. Cotton chromatography under liquid-solid equilibrium conditions revealed oleic acid transfer from cotton to albumin at 27 mole equivalents of 18:1 per mole albumin. Cotton was contrasted with hydrogel, and hydrocolloid wound dressing for its comparative ability to lower elastase activity. Each dressing material evaluated was found to release 18:1 in the presence of albumin with significant inhibition of elastase activity. The 18:1-formulated wound dressings lowered elastase activity in a dose dependent manner in the order cotton gauze > hydrogel > hydrocolloid. In contrast the cationic serine protease Cathepsin G was inihibited by 18:1 within a narrow range of 18:1-cotton formulations. Four per cent Albumin solutions were most effective in binding cotton bound-18:1. However, 2% albumin was sufficient to transfer quantities of 18:1 necessary to achieve a significant elastase-lowering effect. Formulations with 128 mg 18:1/g cotton gauze had equivalent elastase lowering with 1 - 4% albumin. 18:1 bound to cotton wound dressings may have promise in the

  2. Oleic acid and linoleic acid from Tenebrio molitor larvae inhibit BACE1 activity in vitro: molecular docking studies.

    PubMed

    Youn, Kumju; Yun, Eun-Young; Lee, Jinhyuk; Kim, Ji-Young; Hwang, Jae-Sam; Jeong, Woo-Sik; Jun, Mira

    2014-02-01

    In our ongoing research to find therapeutic compounds for Alzheimer's disease (AD) from natural resources, the inhibitory activity of the BACE1 enzyme by Tenebrio molitor larvae and its major compounds were evaluated. The T. molitor larvae extract and its fractions exhibited strong BACE1 suppression. The major components of hexane fraction possessing both high yield and strong BACE1 inhibition were determined by thin layer chromatography, gas chromatography, and nuclear magnetic resonance analysis. A remarkable composition of unsaturated long chain fatty acids, including oleic acid and linoleic acid, were identified. Oleic acid, in particular, noncompetitively attenuated BACE1 activity with a half-maximal inhibitory concentration (IC₅₀) value of 61.31 μM and Ki value of 34.3 μM. Furthermore, the fatty acids were stably interacted with BACE1 at different allosteric sites of the enzyme bound with the OH of CYS319 and the NH₃ of TYR320 for oleic acid and with the C=O group of GLN304 for linoleic acid. Here, we first revealed novel pharmacophore features of oleic acids and linoleic acid to BACE1 by in silico docking studies. The present findings would clearly suggest potential guidelines for designing novel BACE1 selective inhibitors.

  3. Benzbromarone, Quercetin, and Folic Acid Inhibit Amylin Aggregation.

    PubMed

    López, Laura C; Varea, Olga; Navarro, Susanna; Carrodeguas, José A; Sanchez de Groot, Natalia; Ventura, Salvador; Sancho, Javier

    2016-01-01

    Human Amylin, or islet amyloid polypeptide (hIAPP), is a small hormone secreted by pancreatic β-cells that forms aggregates under insulin deficiency metabolic conditions, and it constitutes a pathological hallmark of type II diabetes mellitus. In type II diabetes patients, amylin is abnormally increased, self-assembled into amyloid aggregates, and ultimately contributes to the apoptotic death of β-cells by mechanisms that are not completely understood. We have screened a library of approved drugs in order to identify inhibitors of amylin aggregation that could be used as tools to investigate the role of amylin aggregation in type II diabetes or as therapeutics in order to reduce β-cell damage. Interestingly, three of the compounds analyzed-benzbromarone, quercetin, and folic acid-are able to slow down amylin fiber formation according to Thioflavin T binding, turbidimetry, and Transmission Electron Microscopy assays. In addition to the in vitro assays, we have tested the effect of these compounds in an amyloid toxicity cell culture model and we have found that one of them, quercetin, has the ability to partly protect cultured pancreatic insulinoma cells from the cytotoxic effect of amylin. Our data suggests that quercetin can contribute to reduce oxidative damage in pancreatic insulinoma β cells by modulating the aggregation propensity of amylin. PMID:27322259

  4. Retinoic acid attenuates O2-induced inhibition of lung septation.

    PubMed

    Veness-Meehan, Kathleen A; Pierce, Richard A; Moats-Staats, Billie M; Stiles, Alan D

    2002-11-01

    Exposure of the newborn lung to hyperoxia is associated with impaired alveolar development. In newborn rats exposed to hyperoxia and studied at day 14 of life, retinoic acid (RA) treatment improved survival and increased lung collagen but did not improve alveolar development. To determine whether RA treatment during exposure to hyperoxia results in late improvement in alveolarization, we treated newborn rats with RA and hyperoxia from day 3 to day 14 and then weaned O2 to room air by day 20, and studied the animals on day 42. O2-exposed animals had larger mean lung volumes, larger alveoli, and decreased gas-exchange tissue relative to air-exposed animals, whereas RA-treated O2-exposed animals were not statistically different from air-exposed controls. Relative to control animals, elastin staining at day 14 was decreased in hyperoxia-exposed lung independent of RA treatment, and, at day 42, elastin staining was similar in all treatment groups. At day 14, elastin gene expression was similar in all treatment groups, whereas at day 42 lung previously exposed to hyperoxia showed increased elastin signal independent of RA treatment. These results indicate that RA treatment during hyperoxia exposure promotes septal formation without evidence of effects on elastin gene expression after 4 wk of recovery. PMID:12376350

  5. Proteasome inhibition rescues clinically significant unstable variants of the mismatch repair protein Msh2

    PubMed Central

    Arlow, Tim; Scott, Kristan; Wagenseller, Aubrey; Gammie, Alison

    2013-01-01

    MSH2 is required for DNA mismatch repair recognition in eukaryotes. Deleterious mutations in human MSH2 account for approximately half of the alleles associated with a common hereditary cancer syndrome. Previously, we characterized clinically identified MSH2 missense mutations, using yeast as a model system, and found that the most common cause of defective DNA mismatch repair was low levels of the variant Msh2 proteins. Here, we show that increased protein turnover is responsible for the reduced cellular levels. Increasing gene dosage of more than half of the missense alleles fully restored function. A titration experiment revealed that raising the expression level of one variant to less than wild-type levels restored mismatch repair, suggesting that overexpression is not always required to regain function. We found that the ubiquitin-mediated proteasome degradation pathway is the major mechanism for increased turnover of the Msh2 variants and identified the primary ubiquitin ligase as San1. Deletion of San1 restored protein levels for all but one variant, but did not elevate wild-type Msh2 levels. The unstable variants interacted with San1, whereas wild-type Msh2 did not. Additionally, san1Δ suppressed the mismatch repair defect of unstable variants. Of medical significance, the clinically approved drug Bortezomib partially restored protein levels and mismatch repair function for low-level variants and reversed the resistance to cisplatin, a common chemotherapeutic. Our results provide the foundation for an innovative therapeutic regime for certain mismatch-repair-defective cancers that are refractory to conventional chemotherapies. PMID:23248292

  6. Calcite crystal growth inhibition by humic substances with emphasis on hydrophobic acids from the Florida Everglades

    USGS Publications Warehouse

    Hoch, A.R.; Reddy, M.M.; Aiken, G.R.

    2000-01-01

    The crystallization of calcium carbonate minerals plays an integral role in the water chemistry of terrestrial ecosystems. Humic substances, which are ubiquitous in natural waters, have been shown to reduce or inhibit calcite crystal growth in experiments. The purpose of this study is to quantify and understand the kinetic effects of hydrophobic organic acids isolated from the Florida Everglades and a fulvic acid from Lake Fryxell, Antarctica, on the crystal growth of calcite (CaCO3). Highly reproducible calcite growth experiments were performed in a sealed reactor at constant pH, temperature, supersaturation (?? = 4.5), P(CO2) (10-3.5atm), and ionic strength (0.1 M) with various concentrations of organic acids. Higher plant-derived aquatic hydrophobic acids from the Everglades were more effective growth inhibitors than microbially derived fulvic acid from Lake Fryxell. Organic acid aromaticity correlated strongly with growth inhibition. Molecular weight and heteroatom content correlated well with growth inhibition, whereas carboxyl content and aliphatic nature did not. Copyright (C) 1999 Elsevier Science Ltd.

  7. Lipopolysaccharide inhibits or accelerates biomedical titanium corrosion depending on environmental acidity.

    PubMed

    Yu, Fei; Addison, Owen; Baker, Stephen J; Davenport, Alison J

    2015-09-14

    Titanium and its alloys are routinely used as biomedical implants and are usually considered to be corrosion resistant under physiological conditions. However, during inflammation, chemical modifications of the peri-implant environment including acidification occur. In addition certain biomolecules including lipopolysaccharide (LPS), a component of Gram-negative bacterial cell walls and driver of inflammation have been shown to interact strongly with Ti and modify its corrosion resistance. Gram-negative microbes are abundant in biofilms which form on dental implants. The objective was to investigate the influence of LPS on the corrosion properties of relevant biomedical Ti substrates as a function of environmental acidity. Inductively coupled plasma mass spectrometry was used to quantify Ti dissolution following immersion testing in physiological saline for three common biomedical grades of Ti (ASTM Grade 2, Grade 4 and Grade 5). Complementary electrochemical tests including anodic and cathodic polarisation experiments and potentiostatic measurements were also conducted. All three Ti alloys were observed to behave similarly and ion release was sensitive to pH of the immersion solution. However, LPS significantly inhibited Ti release under the most acidic conditions (pH 2), which may develop in localized corrosion sites, but promoted dissolution at pH 4-7, which would be more commonly encountered physiologically. The observed pattern of sensitivity to environmental acidity of the effect of LPS on Ti corrosion has not previously been reported. LPS is found extensively on the surfaces of skin and mucosal penetrating Ti implants and the findings are therefore relevant when considering the chemical stability of Ti implant surfaces in vivo.

  8. Lipopolysaccharide inhibits or accelerates biomedical titanium corrosion depending on environmental acidity

    PubMed Central

    Yu, Fei; Addison, Owen; Baker, Stephen J; Davenport, Alison J

    2015-01-01

    Titanium and its alloys are routinely used as biomedical implants and are usually considered to be corrosion resistant under physiological conditions. However, during inflammation, chemical modifications of the peri-implant environment including acidification occur. In addition certain biomolecules including lipopolysaccharide (LPS), a component of Gram-negative bacterial cell walls and driver of inflammation have been shown to interact strongly with Ti and modify its corrosion resistance. Gram-negative microbes are abundant in biofilms which form on dental implants. The objective was to investigate the influence of LPS on the corrosion properties of relevant biomedical Ti substrates as a function of environmental acidity. Inductively coupled plasma mass spectrometry was used to quantify Ti dissolution following immersion testing in physiological saline for three common biomedical grades of Ti (ASTM Grade 2, Grade 4 and Grade 5). Complementary electrochemical tests including anodic and cathodic polarisation experiments and potentiostatic measurements were also conducted. All three Ti alloys were observed to behave similarly and ion release was sensitive to pH of the immersion solution. However, LPS significantly inhibited Ti release under the most acidic conditions (pH 2), which may develop in localized corrosion sites, but promoted dissolution at pH 4–7, which would be more commonly encountered physiologically. The observed pattern of sensitivity to environmental acidity of the effect of LPS on Ti corrosion has not previously been reported. LPS is found extensively on the surfaces of skin and mucosal penetrating Ti implants and the findings are therefore relevant when considering the chemical stability of Ti implant surfaces in vivo. PMID:25634122

  9. The Molecular Basis for Dual Fatty Acid Amide Hydrolase (FAAH)/Cyclooxygenase (COX) Inhibition

    PubMed Central

    Palermo, Giulia; Favia, Angelo D.; Convertino, Marino

    2015-01-01

    Abstract The design of multitarget‐directed ligands is a promising strategy for discovering innovative drugs. Here, we report a mechanistic study that clarifies key aspects of the dual inhibition of the fatty acid amide hydrolase (FAAH) and the cyclooxygenase (COX) enzymes by a new multitarget‐directed ligand named ARN2508 (2‐[3‐fluoro‐4‐[3‐(hexylcarbamoyloxy)phenyl]phenyl]propanoic acid). This potent dual inhibitor combines, in a single scaffold, the pharmacophoric elements often needed to block FAAH and COX, that is, a carbamate moiety and the 2‐arylpropionic acid functionality, respectively. Molecular modeling and molecular dynamics simulations suggest that ARN2508 uses a noncovalent mechanism of inhibition to block COXs, while inhibiting FAAH via the acetylation of the catalytic Ser241, in line with previous experimental evidence for covalent FAAH inhibition. This study proposes the molecular basis for the dual FAAH/COX inhibition by this novel hybrid scaffold, stimulating further experimental studies and offering new insights for the rational design of novel anti‐inflammatory agents that simultaneously act on FAAH and COX. PMID:26593700

  10. 2α-Hydroxyursolic Acid Inhibited Cell Proliferation and Induced Apoptosis in MDA-MB-231 Human Breast Cancer Cells through the p38/MAPK Signal Transduction Pathway.

    PubMed

    Jiang, Xue; Li, Tong; Liu, Rui Hai

    2016-03-01

    The mechanisms of action of 2α-hydroxyursolic acid in inhibiting cell proliferation and inducing apoptosis in MDA-MB-231 human breast cancer cells were investigated. The antiproliferative activity and cytotoxicity were determined by the methylene blue assay. The expression of proteins was determined using Western blot. 2α-Hydroxyursolic acid significantly inhibited MDA-MB-231 cell proliferation, and no cytotoxicity was observed at concentrations below 30 μM. 2α-Hydroxyursolic acid significantly down-regulated expressions of TRAF2, PCNA, cyclin D1, and CDK4 and up-regulated the expressions of p-ASK1, p-p38, p-p53, and p-21. 2α-Hydroxyursolic acid induced apoptosis in MDA-MB-231 cells by significantly increasing the Bax/Bcl-2 ratio and inducing the cleaved caspase-3. Additionally, treatment of SB203580, a p38 MAPK specific inhibitor, reversed the inhibition of PCNA, cyclin D1, and Bcl-2 expression induced by 2α-hydroxyursolic acid in MDA-MB-231 cells. These results suggested that 2α-hydroxyursolic acid exhibited anticancer activity through the inhibition of cell proliferation and the induction of apoptosis by regulating the p38/MAPK signal transduction pathway.

  11. Hydrophobic bile acids relax rat detrusor contraction via inhibiting the opening of the Na+/Ca2+ exchanger

    PubMed Central

    Zhu, Jingzhen; Dong, Xingyou; Liu, Qian; Wu, Chao; Wang, Qingqing; Long, Zhou; Li, Longkun

    2016-01-01

    Hydrophobic bile acids (BAs) are thought to inhibit smooth muscle contractility in several organs. The present study was undertaken to investigate the effects of hydrophobic BAs on the detrusor contractility of rat bladder and to explore the possible mechanism. Lithocholic acid (LCA) treatment increased the micturition interval and induced a concentration-dependent relaxation of bladder detrusor strips. In addition, LCA reduced the concentration of intracellular free Ca2+([Ca2+]i) and inhibited both the outward and inward Na+/Ca2+ exchanger (NCX) current (INCX) in primary isolated smooth muscle cells (SMCs). To further investigate the mechanism of action of LCA, several pharmacologic agents were used. We found that the NCX inhibitor 3′,4′-Dichlorobenzamil (DCB) can significantly inhibit the relaxation of detrusor strips and a reduction of the [Ca2+]i induced by LCA, while the antagonist of muscarinic receptor and the agonist of the G protein-coupled bile acid receptor (TGR5) and the farnesoid X receptor (FXR) had no effect. In conclusion, these data suggest that the relaxation of rat detrusor induced by hydrophobic BAs is mediated by NCX. Further research is needed to carry out to demonstrate the possible pathway and provide a potential new strategy to investigation for the treatment of the low urinary tract syndromes. PMID:26892434

  12. Photodegradation and inhibition of drug-resistant influenza virus neuraminidase using anthraquinone-sialic acid hybrids.

    PubMed

    Aoki, Yusuke; Tanimoto, Shuho; Takahashi, Daisuke; Toshima, Kazunobu

    2013-02-11

    The anthraquinone-sialic acid hybrids designed effectively degraded not only non-drug-resistant neuraminidase but also drug-resistant neuraminidase, which is an important target of anti-influenza therapy. Degradation was achieved using long-wavelength UV radiation in the absence of any additives and under neutral conditions. Moreover, the hybrids efficiently inhibited neuraminidase activities upon photo-irradiation. PMID:23282898

  13. Selective inhibition of fatty acid oxidation in colonocytes by ibuprofen: a cause of colitis?

    PubMed Central

    Roediger, W E; Millard, S

    1995-01-01

    Ibuprofen is associated with initiation or exacerbation of ulcerative colitis. As ibuprofen selectively inhibited fatty acid oxidation in the liver or caused mitochondrial damage in intestinal cells, its effect on substrate oxidation by isolated colonocytes of man and rat was examined. Ibuprofen dose dependently (2.0-7.5 mmol/l) and selectively inhibited 14CO2 production from labelled n-butyrate in colonocytes from the proximal and distal human colon (n = 12, p = < 0.001). Glucose oxidation was either unaltered or increased. Because short chain fatty acid oxidation is the main source of acetyl-CoA for long chain fatty acid synthesis, the inhibition of prostaglandin synthesis by ibuprofen in the colonic mucosa could also occur at this level. Because the concentrations of ibuprofen that can be attained in the human colon are not known, conclusions drawn from current dosages are tentative. The inhibition of fatty acid oxidation by ibuprofen may be biochemically implicated in the initiation and exacerbation of ulcerative colitis, manifestation of which would depend on the ibuprofen concentrations reached in the colon. PMID:7890237

  14. Cinnamic-derived acids significantly affect Fusarium graminearum growth and in vitro synthesis of type B trichothecenes.

    PubMed

    Ponts, Nadia; Pinson-Gadais, Laetitia; Boutigny, Anne-Laure; Barreau, Christian; Richard-Forget, Florence

    2011-08-01

    The impact of five phenolic acids (ferulic, coumaric, caffeic, syringic, and p-hydroxybenzoic acids) on fungal growth and type B trichothecene production by four strains of Fusarium graminearum was investigated. All five phenolic acids inhibited growth but the degree of inhibition varied between strains. Our results suggested that the more lipophilic phenolic acids are, the higher is the effect they have on growth. Toxin accumulation in phenolic acid-supplemented liquid glucose, yeast extract, and peptone cultures was enhanced in the presence of ferulic and coumaric acids but was reduced in the presence of p-hydroxybenzoic acid. This modulation was shown to correlate with a regulation of TRI5 transcription. In this study, addition of phenolic acids with greater antioxidant properties resulted in a higher toxin accumulation, indicating that the modulation of toxin accumulation may be linked to the antioxidant properties of the phenolic acids. These data suggest that, in planta, different compositions in phenolic acids of kernels from various cultivars may reflect different degrees of sensitivity to "mycotoxinogenesis."

  15. Fatty acid synthesis is inhibited by inefficient utilization of unusual fatty acids for glycerolipid assembly.

    PubMed

    Bates, Philip D; Johnson, Sean R; Cao, Xia; Li, Jia; Nam, Jeong-Won; Jaworski, Jan G; Ohlrogge, John B; Browse, John

    2014-01-21

    Degradation of unusual fatty acids through β-oxidation within transgenic plants has long been hypothesized as a major factor limiting the production of industrially useful unusual fatty acids in seed oils. Arabidopsis seeds expressing the castor fatty acid hydroxylase accumulate hydroxylated fatty acids up to 17% of total fatty acids in seed triacylglycerols; however, total seed oil is also reduced up to 50%. Investigations into the cause of the reduced oil phenotype through in vivo [(14)C]acetate and [(3)H]2O metabolic labeling of developing seeds surprisingly revealed that the rate of de novo fatty acid synthesis within the transgenic seeds was approximately half that of control seeds. RNAseq analysis indicated no changes in expression of fatty acid synthesis genes in hydroxylase-expressing plants. However, differential [(14)C]acetate and [(14)C]malonate metabolic labeling of hydroxylase-expressing seeds indicated the in vivo acetyl-CoA carboxylase activity was reduced to approximately half that of control seeds. Therefore, the reduction of oil content in the transgenic seeds is consistent with reduced de novo fatty acid synthesis in the plastid rather than fatty acid degradation. Intriguingly, the coexpression of triacylglycerol synthesis isozymes from castor along with the fatty acid hydroxylase alleviated the reduced acetyl-CoA carboxylase activity, restored the rate of fatty acid synthesis, and the accumulation of seed oil was substantially recovered. Together these results suggest a previously unidentified mechanism that detects inefficient utilization of unusual fatty acids within the endoplasmic reticulum and activates an endogenous pathway for posttranslational reduction of fatty acid synthesis within the plastid.

  16. d-Amino Acids Do Not Inhibit Biofilm Formation in Staphylococcus aureus

    PubMed Central

    Sarkar, Sourav; Pires, Marcos M.

    2015-01-01

    Bacteria can either exist in the planktonic (free floating) state or in the biofilm (encased within an organic framework) state. Bacteria biofilms cause industrial concerns and medical complications and there has been a great deal of interest in the discovery of small molecule agents that can inhibit the formation of biofilms or disperse existing structures. Herein we show that, contrary to previously published reports, d-amino acids do not inhibit biofilm formation of Bacillus subtilis (B. subtilis), Staphylococcus aureus (S. aureus), and Staphylococcus epidermis (S. epidermis) at millimolar concentrations. We evaluated a diverse set of natural and unnatural d-amino acids and observed no activity from these compounds in inhibiting biofilm formation. PMID:25658642

  17. d-Amino acids do not inhibit biofilm formation in Staphylococcus aureus.

    PubMed

    Sarkar, Sourav; Pires, Marcos M

    2015-01-01

    Bacteria can either exist in the planktonic (free floating) state or in the biofilm (encased within an organic framework) state. Bacteria biofilms cause industrial concerns and medical complications and there has been a great deal of interest in the discovery of small molecule agents that can inhibit the formation of biofilms or disperse existing structures. Herein we show that, contrary to previously published reports, d-amino acids do not inhibit biofilm formation of Bacillus subtilis (B. subtilis), Staphylococcus aureus (S. aureus), and Staphylococcus epidermis (S. epidermis) at millimolar concentrations. We evaluated a diverse set of natural and unnatural d-amino acids and observed no activity from these compounds in inhibiting biofilm formation. PMID:25658642

  18. Retinoic acid receptor alpha mediates growth inhibition by retinoids in human colon carcinoma HT29 cells.

    PubMed

    Nicke, B; Kaiser, A; Wiedenmann, B; Riecken, E O; Rosewicz, S

    1999-08-11

    Although retinoids have been suggested to inhibit chemically induced colon carcinogenesis, the molecular mechanisms underlying retinoid-mediated growth regulation in colon carcinoma cells are unknown. Therefore, we investigated the biological effects of retinoids on growth in HT29 colon carcinoma cells. All-trans retinoic acid (ATRA) treatment of HT29 cells resulted in a profound inhibition of anchorage-independent growth without biochemical or morphological evidence for induction of differentiation. Treatment with the selective RARalpha agonist Ro 40-6055 completely mimicked the effects of ATRA on growth and transactivation of a betaRAREx2-luciferase reporter construct, while RARbeta- and gamma-specific analogues were ineffective. Furthermore, ATRA-regulated growth and transactivation could be completely blocked by a RARalpha-selective receptor antagonist. Thus, ATRA potently inhibits anchorage-independent growth in HT29 cells and this effect is mainly if not exclusively mediated by the retinoic acid receptor alpha.

  19. Zoledronic acid inhibits pulmonary metastasis dissemination in a preclinical model of Ewing’s sarcoma via inhibition of cell migration

    PubMed Central

    2014-01-01

    Background Ewing’s sarcoma (ES) is the second most frequent primitive malignant bone tumor in adolescents with a very poor prognosis for high risk patients, mainly when lung metastases are detected (overall survival <15% at 5 years). Zoledronic acid (ZA) is a potent inhibitor of bone resorption which induces osteoclast apoptosis. Our previous studies showed a strong therapeutic potential of ZA as it inhibits ES cell growth in vitro and ES primary tumor growth in vivo in a mouse model developed in bone site. However, no data are available on lung metastasis. Therefore, the aim of this study was to determine the effect of ZA on ES cell invasion and metastatic properties. Methods Invasion assays were performed in vitro in Boyden’s chambers covered with Matrigel. Matrix Metalloproteinase (MMP) activity was analyzed by zymography in ES cell culture supernatant. In vivo, a relevant model of spontaneous lung metastases which disseminate from primary ES tumor was induced by the orthotopic injection of 106 human ES cells in the tibia medullar cavity of nude mice. The effect of ZA (50 μg/kg, 3x/week) was studied over a 4-week period. Lung metastases were observed macroscopically at autopsy and analysed by histology. Results ZA induced a strong inhibition of ES cell invasion, probably due to down regulation of MMP-2 and −9 activities as analyzed by zymography. In vivo, ZA inhibits the dissemination of spontaneous lung metastases from a primary ES tumor but had no effect on the growth of established lung metastases. Conclusion These results suggest that ZA could be used early in the treatment of ES to inhibit bone tumor growth but also to prevent the early metastatic events to the lungs. PMID:24612486

  20. Artemisinin and its derivatives can significantly inhibit lung tumorigenesis and tumor metastasis through Wnt/β-catenin signaling

    PubMed Central

    Zheng, Hongming; Zheng, Liang; Liu, Wenqin; Wu, Jinjun; Ou, Rilan; Zhang, Guiyu; Li, Fangyuan; Hu, Ming; Liu, Zhongqiu; Lu, Linlin

    2016-01-01

    Non-small-cell lung cancer (NSCLC) is the most prevalent malignancy worldwide given its high incidence, considerable mortality, and poor prognosis. The anti-malaria compounds artemisinin (ART), dihydroartemisinin (DHA), and artesunate (ARTS) reportedly have anti-cancer potential, although the underlying mechanisms remain unclear. In this work, we used flow cytometry to show that ART, DHA, and ARTS could inhibit the proliferation of A549 and H1299 cells by arresting cell cycle in G1 phase. Meanwhile, tumor malignancy including migration, invasion, cancer stem cells, and epithelial–mesenchymal transition were also significantly suppressed by these compounds. Furthermore, ART, DHA, and ARTS remarkably decreased tumor growth in vivo. By using IWP-2, the inhibitor of Wnt/β-catenin pathway, and Wnt5a siRNA, we found that ART, DHA, and ARTS could render tumor inhibition partially dependent on Wnt/β-catenin inactivation. These compounds could strikingly decrease the protein level of Wnt5-a/b and simultaneously increase those of NKD2 and Axin2, ultimately resulting in β-catenin downregulation. In summary, our findings revealed that ART, DHA, and ARTS could suppress lung-tumor progression by inhibiting Wnt/β-catenin pathway, thereby suggesting a novel target for ART, DHA, and ARTS in cancer treatment. PMID:27119499

  1. Sialic Acid Is Required for Neuronal Inhibition by Soluble MAG but not for Membrane Bound MAG

    PubMed Central

    Al-Bashir, Najat; Mellado, Wilfredo; Filbin, Marie T.

    2016-01-01

    Myelin-Associated Glycoprotein (MAG), a major inhibitor of axonal growth, is a member of the immunoglobulin (Ig) super-family. Importantly, MAG (also known as Siglec-4) is a member of the Siglec family of proteins (sialic acid-binding, immunoglobulin-like lectins), MAG binds to complex gangliosides, specifically GD1a and/or GT1b. Therefore, it has been proposed as neuronal receptors for MAG inhibitory effect of axonal growth. Previously, we showed that MAG binds sialic acid through domain 1 at Arg118 and is able to inhibit axonal growth through domain 5. We developed a neurite outgrowth (NOG) assay, in which both wild type MAG and mutated MAG (MAG Arg118) are expressed on cells. In addition we also developed a soluble form NOG in which we utilized soluble MAG-Fc and mutated MAG (Arg118-Fc). Only MAG-Fc is able to inhibit NOG, but not mutated MAG (Arg118)-Fc that has been mutated at its sialic acid binding site. However, both forms of membrane bound MAG- and MAG (Arg118)- expressing cells still inhibit NOG. Here, we review various results from different groups regarding MAG’s inhibition of axonal growth. Also, we propose a model in which the sialic acid binding is not necessary for the inhibition induced by the membrane form of MAG, but it is necessary for the soluble form of MAG. This finding highlights the importance of understanding the different mechanisms by which MAG inhibits NOG in both the soluble fragmented form and the membrane-bound form in myelin debris following CNS damage. PMID:27065798

  2. Inhibition of lysophospholipase D activity by unsaturated lysophosphatidic acids or seed extracts containing 1-linoleoyl and 1-oleoyl lysophosphatidic acid.

    PubMed

    Liu, Xi-Wen; Sok, Dai-Eun; Yook, Hong-Sun; Sohn, Cheon-Bae; Chung, Young-Jin; Kim, Mee Ree

    2007-10-17

    Lysophospholipase D (lysoPLD), generating lipid mediator lysophosphatidic acid (LPA) from lysophosphatidyclcholine (LPC), is known to be inhibited by lysophosphatidic acids. Meanwhile, some plant lipids are known to contain lysophospholipids as minor components. Therefore, it is interesting to test whether edible seed samples, rich in phospholipids, may contain lysophospholipids, which express a strong inhibition of lysoPLD activity. First, the structural importance of fatty acyl group in LPAs was examined by determining the inhibitory effect of various LPAs on bovine lysoPLD activity. The most potent in the inhibition of lysoPLD activity was linoleoyl-LPA ( K i, 0.21 microM), followed by arachidonoyl-LPA ( K i, 0.55 microM), oleoyl-LPA ( K i, 1.2 microM), and palmitoyl-LPA ( K i, 1.4 microM), based on the fluoresecent assay. The same order of inhibitory potency among LPA analogs with different acyl chains was also found in the spectrophotometric assay. Subsequently, the extracts of 12 edible seeds were screened for the inhibition of lysoPLD activity using both spectrophotometric and fluorescent assays. Among seed extracts tested, the extract from soybean seed, sesame seed, or sunflower seed (30 mg seed weight/mL) was found to exhibit a potent inhibition (>80%) of lysoPLD activity. In further study employing ESI-MS/MS analysis, major LPA components in seed extracts were identified to be 1-linoleoyl LPA, 1-oleoyl LPA, and 1-palmitoyl LPA with 1-linoleoyl LPA being more predominant. Thus, the potent inhibition of lysoPLD activity by seed extracts might be ascribed to the presence of LPA with linoleoyl group rather than other acyl chains. PMID:17887800

  3. Analgesic effects of fatty acid amide hydrolase inhibition in a rat model of neuropathic pain.

    PubMed

    Jhaveri, Maulik D; Richardson, Denise; Kendall, David A; Barrett, David A; Chapman, Victoria

    2006-12-20

    Cannabinoid-based medicines have therapeutic potential for the treatment of pain. Augmentation of levels of endocannabinoids with inhibitors of fatty acid amide hydrolase (FAAH) is analgesic in models of acute and inflammatory pain states. The aim of this study was to determine whether local inhibition of FAAH alters nociceptive responses of spinal neurons in the spinal nerve ligation model of neuropathic pain. Electrophysiological studies were performed 14-18 d after spinal nerve ligation or sham surgery, and the effects of the FAAH inhibitor cyclohexylcarbamic acid 3-carbamoyl biphenyl-3-yl ester (URB597) on mechanically evoked responses of spinal neurons and levels of endocannabinoids were determined. Intraplantar URB597 (25 microg in 50 microl) significantly (p < 0.01) attenuated mechanically evoked responses of spinal neurons in sham-operated rats. Effects of URB597 were blocked by the cannabinoid 1 receptor (CB1) antagonist AM251 [N-1-(2,4-dichlorophenyl)-5-(4-iodophenyl)-4-methyl-N-1-piperidinyl-1H-pyrazole-3-carboxamide] (30 microg in 50 microl) and the opioid receptor antagonist naloxone. URB597 treatment increased levels of anandamide, 2-arachidonyl glycerol, and oleoyl ethanolamide in the ipsilateral hindpaw of sham-operated rats. Intraplantar URB597 (25 microg in 50 microl) did not, however, alter mechanically evoked responses of spinal neurons in spinal nerve ligated (SNL) rats or hindpaw levels of endocannabinoids. Intraplantar injection of a higher dose of URB597 (100 microg in 50 microl) significantly (p < 0.05) attenuated evoked responses of spinal neurons in SNL rats but did not alter hindpaw levels of endocannabinoids. Spinal administration of URB597 attenuated evoked responses of spinal neurons and elevated levels of endocannabinoids in sham-operated and SNL rats. These data suggest that peripheral FAAH activity may be altered or that alternative pathways of metabolism have greater importance in SNL rats.

  4. Electrophilic Fatty Acid Species Inhibit 5-Lipoxygenase and Attenuate Sepsis-Induced Pulmonary Inflammation

    PubMed Central

    Awwad, Khader; Steinbrink, Svenja D.; Frömel, Timo; Lill, Nicole; Isaak, Johann; Häfner, Ann-Kathrin; Roos, Jessica; Hofmann, Bettina; Heide, Heinrich; Geisslinger, Gerd; Steinhilber, Dieter; Freeman, Bruce A.; Maier, Thorsten J.; Fleming, Ingrid

    2014-01-01

    Abstract Aims: The reaction of nitric oxide and nitrite-derived species with polyunsaturated fatty acids yields electrophilic fatty acid nitroalkene derivatives (NO2-FA), which display anti-inflammatory properties. Given that the 5-lipoxygenase (5-LO, ALOX5) possesses critical nucleophilic amino acids, which are potentially sensitive to electrophilic modifications, we determined the consequences of NO2-FA on 5-LO activity in vitro and on 5-LO-mediated inflammation in vivo. Results: Stimulation of human polymorphonuclear leukocytes (PMNL) with nitro-oleic (NO2-OA) or nitro-linoleic acid (NO2-LA) (but not the parent lipids) resulted in the concentration-dependent and irreversible inhibition of 5-LO activity. Similar effects were observed in cell lysates and using the recombinant human protein, indicating a direct reaction with 5-LO. NO2-FAs did not affect the activity of the platelet-type 12-LO (ALOX12) or 15-LO-1 (ALOX15) in intact cells or the recombinant protein. The NO2-FA-induced inhibition of 5-LO was attributed to the alkylation of Cys418, and the exchange of Cys418 to serine rendered 5-LO insensitive to NO2-FA. In vivo, the systemic administration of NO2-OA to mice decreased neutrophil and monocyte mobilization in response to lipopolysaccharide (LPS), attenuated the formation of the 5-LO product 5-hydroxyeicosatetraenoic acid (5-HETE), and inhibited lung injury. The administration of NO2-OA to 5-LO knockout mice had no effect on LPS-induced neutrophil or monocyte mobilization as well as on lung injury. Innovation: Prophylactic administration of NO2-OA to septic mice inhibits inflammation and promotes its resolution by interfering in 5-LO-mediated inflammatory processes. Conclusion: NO2-FAs directly and irreversibly inhibit 5-LO and attenuate downstream acute inflammatory responses. Antioxid. Redox Signal. 20, 2667–2680. PMID:24206143

  5. Corrosion Inhibition of Carbon Steel by New Thiophene Azo Dye Derivatives in Acidic Solution

    NASA Astrophysics Data System (ADS)

    El-Haddad, Mahmoud N.; Fouda, A. S.; Mostafa, H. A.

    2013-08-01

    Inhibition of carbon steel corrosion in 2 M hydrochloric acid (HCl) solution by thiophene azo dye derivatives were studied using weight loss, electrochemical frequency modulation (EFM), and atomic absorption techniques. The experimental data suggest that the inhibition efficiency increases with increasing inhibitors concentration in presence of 103 μM potassium iodide (KI). This is due to synergistic effect. Thus, the experimental results suggested that the presence of these anions in the solution stabilized the adsorption of inhibitors molecules on the metal surface and improved the inhibition efficiency. The results of EFM experiments are a spectrum of current response as a function of frequency. The corrosion rate and Tafel parameters can be obtained with measurement by analyzing the harmonic frequencies. The adsorption of the inhibitors on metal surface obeys the Langmuir adsorption isotherm. The surface of metal examined using Fourier transform infrared and ultraviolet spectroscopy. Quantum chemical calculations were carried out and relations between computed parameters and experimental inhibition efficiency were discussed.

  6. Direct Inhibition of Cellular Fatty Acid Synthase Impairs Replication of Respiratory Syncytial Virus and Other Respiratory Viruses.

    PubMed

    Ohol, Yamini M; Wang, Zhaoti; Kemble, George; Duke, Gregory

    2015-01-01

    Fatty acid synthase (FASN) catalyzes the de novo synthesis of palmitate, a fatty acid utilized for synthesis of more complex fatty acids, plasma membrane structure, and post-translational palmitoylation of host and viral proteins. We have developed a potent inhibitor of FASN (TVB-3166) that reduces the production of respiratory syncytial virus (RSV) progeny in vitro from infected human lung epithelial cells (A549) and in vivo from mice challenged intranasally with RSV. Addition of TVB-3166 to the culture medium of RSV-infected A549 cells reduces viral spread without inducing cytopathic effects. The antiviral effect of the FASN inhibitor is a direct consequence of reducing de novo palmitate synthesis; similar doses are required for both antiviral activity and inhibition of palmitate production, and the addition of exogenous palmitate to TVB-3166-treated cells restores RSV production. TVB-3166 has minimal effect on RSV entry but significantly reduces viral RNA replication, protein levels, viral particle formation and infectivity of released viral particles. TVB-3166 substantially impacts viral replication, reducing production of infectious progeny 250-fold. In vivo, oral administration of TVB-3166 to RSV-A (Long)-infected BALB/c mice on normal chow, starting either on the day of infection or one day post-infection, reduces RSV lung titers 21-fold and 9-fold respectively. Further, TVB-3166 also inhibits the production of RSV B, human parainfluenza 3 (PIV3), and human rhinovirus 16 (HRV16) progeny from A549, HEp2 and HeLa cells respectively. Thus, inhibition of FASN and palmitate synthesis by TVB-3166 significantly reduces RSV progeny both in vitro and in vivo and has broad-spectrum activity against other respiratory viruses. FASN inhibition may alter the composition of regions of the host cell membrane where RSV assembly or replication occurs, or change the membrane composition of RSV progeny particles, decreasing their infectivity.

  7. Direct Inhibition of Cellular Fatty Acid Synthase Impairs Replication of Respiratory Syncytial Virus and Other Respiratory Viruses

    PubMed Central

    Ohol, Yamini M.; Wang, Zhaoti; Kemble, George; Duke, Gregory

    2015-01-01

    Fatty acid synthase (FASN) catalyzes the de novo synthesis of palmitate, a fatty acid utilized for synthesis of more complex fatty acids, plasma membrane structure, and post-translational palmitoylation of host and viral proteins. We have developed a potent inhibitor of FASN (TVB-3166) that reduces the production of respiratory syncytial virus (RSV) progeny in vitro from infected human lung epithelial cells (A549) and in vivo from mice challenged intranasally with RSV. Addition of TVB-3166 to the culture medium of RSV-infected A549 cells reduces viral spread without inducing cytopathic effects. The antiviral effect of the FASN inhibitor is a direct consequence of reducing de novo palmitate synthesis; similar doses are required for both antiviral activity and inhibition of palmitate production, and the addition of exogenous palmitate to TVB-3166-treated cells restores RSV production. TVB-3166 has minimal effect on RSV entry but significantly reduces viral RNA replication, protein levels, viral particle formation and infectivity of released viral particles. TVB-3166 substantially impacts viral replication, reducing production of infectious progeny 250-fold. In vivo, oral administration of TVB-3166 to RSV-A (Long)-infected BALB/c mice on normal chow, starting either on the day of infection or one day post-infection, reduces RSV lung titers 21-fold and 9-fold respectively. Further, TVB-3166 also inhibits the production of RSV B, human parainfluenza 3 (PIV3), and human rhinovirus 16 (HRV16) progeny from A549, HEp2 and HeLa cells respectively. Thus, inhibition of FASN and palmitate synthesis by TVB-3166 significantly reduces RSV progeny both in vitro and in vivo and has broad-spectrum activity against other respiratory viruses. FASN inhibition may alter the composition of regions of the host cell membrane where RSV assembly or replication occurs, or change the membrane composition of RSV progeny particles, decreasing their infectivity. PMID:26659560

  8. Inhibition of succinic acid production in metabolically engineered Escherichia coli by neutralizing agent, organic acids, and osmolarity.

    PubMed

    Andersson, Christian; Helmerius, Jonas; Hodge, David; Berglund, Kris A; Rova, Ulrika

    2009-01-01

    The economical viability of biochemical succinic acid production is a result of many processing parameters including final succinic acid concentration, recovery of succinate, and the volumetric productivity. Maintaining volumetric productivities >2.5 g L(-1) h(-1) is important if production of succinic acid from renewable resources should be competitive. In this work, the effects of organic acids, osmolarity, and neutralizing agent (NH4OH, KOH, NaOH, K2CO3, and Na2CO3), and Na2CO3) on the fermentative succinic acid production by Escherichia coli AFP184 were investigated. The highest concentration of succinic acid, 77 g L(-1), was obtained with Na2CO3. In general, irrespective of the base used, succinic acid productivity per viable cell was significantly reduced as the concentration of the produced acid increased. Increased osmolarity resulting from base addition during succinate production only marginally affected the productivity per viable cell. Addition of the osmoprotectant glycine betaine to cultures resulted in an increased aerobic growth rate and anaerobic glucose consumption rate, but decreased succinic acid yield. When using NH4OH productivity completely ceased at a succinic acid concentration of approximately 40 g L(-1). Volumetric productivities remained at 2.5 g L(-1) h(-1) for up to 10 h longer when K- or Na-bases where used instead of NH4OH. The decrease in cellular succinic acid productivity observed during the anaerobic phase was found to be due to increased organic acid concentrations rather than medium osmolarity.

  9. Identification of significant medium components that affect docosahexaenoic acid production by Schizochytrium sp. SW1

    NASA Astrophysics Data System (ADS)

    Manikan, Vidyah; Hamid, Aidil A.

    2013-11-01

    Central composite design (CCD) was employed to investigate the significance of glucose, yeast extract, MSG and sea salt in affecting the amount of docosahexaenoic acid (DHA) accumulated by a locally isolated strain of Schizochytrium. Design Expert software was used to construct a set of experiments where each medium component mentioned above was varied over three levels. Cultivation was carried out in 250mL flasks containing 50mL of medium, incubated at 30°C with 200 rpm agitation for 96 hours. ANOVA was conducted to identify the influential factors and the level of their significance where factors that scored a probability value of less than 0.05 were considered significant. The level of influence for each independent variable was also interpreted using perturbation whereas pattern of interaction between the factors were interpreted using interaction plots. This experiment revealed that yeast extract and monosodium glutamate have significant influence on DHA accumulation process by Schizochytrium sp. SW1.

  10. Time dependent inhibition of xanthine oxidase in irradiated solutions of folic acid, aminopterin and methotrexate

    SciTech Connect

    Robinson, K.; Pilot, T.F.; Meany, J.E. )

    1990-01-01

    The xanthine oxidase catalyzed oxidation of hypoxanthine was followed by monitoring the formation of uric acid at 290 nm. Inhibition of xanthine oxidase occurs in aqueous solutions of folic acid methotrexate and aminopterin. These compounds are known to dissociate upon exposure to ultraviolet light resulting in the formation of their respective 6-formylpteridine derivatives. The relative rates of dissociation were monitored spectrophotometrically by determining the absorbance of their 2,4-dinitrophenylhydrazine derivatives at 500 nm. When aqueous solutions of folic acid, aminopterin and methotrexate were exposed to uv light, a direct correlation was observed between the concentrations of the 6-formylpteridine derivatives existing in solution and the ability of these solutions to inhibit xanthine oxidase. The relative potency of the respective photolysis products were estimated.

  11. The role of citric acid in oral peptide and protein formulations: relationship between calcium chelation and proteolysis inhibition.

    PubMed

    Welling, Søren H; Hubálek, František; Jacobsen, Jette; Brayden, David J; Rahbek, Ulrik L; Buckley, Stephen T

    2014-04-01

    The excipient citric acid (CA) has been reported to improve oral absorption of peptides by different mechanisms. The balance between its related properties of calcium chelation and permeation enhancement compared to a proteolysis inhibition was examined. A predictive model of CA's calcium chelation activity was developed and verified experimentally using an ion-selective electrode. The effects of CA, its salt (citrate, Cit) and the established permeation enhancer, lauroyl carnitine chloride (LCC) were compared by measuring transepithelial electrical resistance (TEER) and permeability of insulin and FD4 across Caco-2 monolayers and rat small intestinal mucosae mounted in Ussing chambers. Proteolytic degradation of insulin was determined in rat luminal extracts across a range of pH values in the presence of CA. CA's capacity to chelate calcium decreased ~10-fold for each pH unit moving from pH 6 to pH 3. CA was an inferior weak permeation enhancer compared to LCC in both in vitro models using physiological buffers. At pH 4.5 however, degradation of insulin in rat luminal extracts was significantly inhibited in the presence of 10mM CA. The capacity of CA to chelate luminal calcium does not occur significantly at the acidic pH values where it effectively inhibits proteolysis, which is its dominant action in oral peptide formulations. On account of insulin's low basal permeability, inclusion of alternative permeation enhancers is likely to be necessary to achieve sufficient oral bioavailability since this is a weak property of CA.

  12. Rosmarinic Acid Attenuates Sodium Taurocholate-Induced Acute Pancreatitis in Rats by Inhibiting Nuclear Factor-κB Activation.

    PubMed

    Fan, Yu-Ting; Yin, Guo-Jian; Xiao, Wen-Qin; Qiu, Lei; Yu, Ge; Hu, Yan-Ling; Xing, Miao; Wu, De-Qing; Cang, Xiao-Feng; Wan, Rong; Wang, Xing-Peng; Hu, Guo-Yong

    2015-01-01

    Rosmarinic Acid (RA), a caffeic acid ester, has been shown to exert anti-inflammation, anti-oxidant and antiallergic effects. Our study aimed to investigate the effect of RA in sodium taurocholate ( NaTC )-induced acute pancreatitis, both in vivo and in vitro. In vivo, RA (50 mg/kg) was administered intraperitoneally 2 h before sodium taurocholate injection. Rats were sacrificed 12 h, 24 h or 48 h after sodium taurocholate injection. Pretreatment with RA significantly ameliorated pancreas histopathological changes, decreased amylase and lipase activities in serum, lowered myeloperoxidase activity in the pancreas, reduced systematic and pancreatic interleukin-1 β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α) levels, and inhibited NF-κB translocation in pancreas. In vitro, pretreating the fresh rat pancreatic acinar cells with 80 μ mol/L RA 2 h before 3750 nmol/L sodium taurocholate or 10 ng/L TNF-α administration significantly attenuated the reduction of isolated pancreatic acinar cell viability and inhibited the nuclear activation and translocation of NF-κB. Based on our findings, RA appears to attenuate damage in sodium taurocholate-induced acute pancreatitis and reduce the release of inflammatory cytokines by inhibiting the activation of NF-κB. These findings might provide a basis for investigating the therapeutic role of RA in managing acute pancreatits. PMID:26364660

  13. Tannic Acid Inhibits Hepatitis C Virus Entry into Huh7.5 Cells

    PubMed Central

    Hagedorn, Curt H.

    2015-01-01

    Chronic infection with the hepatitis C virus (HCV) is a cause of cirrhosis and hepatocellular carcinoma worldwide. Although antiviral therapy has dramatically improved recently, a number of patients remain untreated and some do not clear infection with treatment. Viral entry is an essential step in initiating and maintaining chronic HCV infections. One dramatic example of this is the nearly 100% infection of newly transplanted livers in patients with chronic hepatitis C. HCV entry inhibitors could play a critical role in preventing HCV infection of newly transplanted livers. Tannic acid, a polymer of gallic acid and glucose molecules, is a plant-derived polyphenol that defends some plants from insects and microbial infections. It has been shown to have a variety of biological effects, including antiviral activity, and is used as a flavoring agent in foods and beverages. In this study, we demonstrate that tannic acid is a potent inhibitor of HCV entry into Huh7.5 cells at low concentrations (IC50 5.8 μM). It also blocks cell-to-cell spread in infectious HCV cell cultures, but does not inhibit HCV replication following infection. Moreover, experimental results indicate that tannic acid inhibits an early step of viral entry, such as the docking of HCV at the cell surface. Gallic acid, tannic acid’s structural component, did not show any anti-HCV activity including inhibition of HCV entry or replication at concentrations up to 25 μM. It is possible the tannin structure is related on the effect on HCV inhibition. Tannic acid, which is widely distributed in plants and foods, has HCV antiviral activity in cell culture at low micromolar concentrations, may provide a relative inexpensive adjuvant to direct-acting HCV antivirals and warrants future investigation. PMID:26186636

  14. Inhibition of N2 fixation in soybean is associated with elevated ureides and amino acids.

    PubMed

    King, C Andy; Purcell, Larry C

    2005-04-01

    Decreased N2 fixation in soybean (Glycine max) L. Merr. during water deficits has been associated with increases in ureides and free amino acids in plant tissues, indicating a potential feedback inhibition by these compounds in response to drought. We evaluated concentrations of ureides and amino acids in leaf and nodule tissue and the concurrent change in N2 fixation in response to exogenous ureides and soil-water treatments for the cultivars Jackson and KS4895. Exogenous ureides applied to the soil and water-deficit treatments inhibited N2 fixation by 85% to 90%. Mn fertilization increased the apparent catabolism of ureides in leaves and hastened the recovery of N2 fixation following exogenous ureide application for both cultivars. Ureides and total free amino acids in leaves and nodules increased during water deficits and coincided with a decline in N2 fixation for both cultivars. N2 fixation recovered to 74% to 90% of control levels 2 d after rewatering drought-stressed plants, but leaf ureides and total nodule amino acids remained elevated in KS4895. Asparagine accounted for 82% of the increase in nodule amino acids relative to well-watered plants at 2 d after rewatering. These results indicate that leaf ureides and nodule asparagine do not feedback inhibit N2 fixation. Compounds whose increase and decrease in concentration mirrored the decline and recovery of N2 fixation included nodule ureides, nodule aspartate, and several amino acids in leaves, indicating that these are potential candidate molecules for feedback inhibition of N2 fixation.

  15. Use of jasmonic acid and salicylic acid to inhibit growth of sugarbeet storage rot pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Jasmonic acid (JA) and salicylic acid (SA) are endogenous plant hormones that induce native plant defense responses and provide protection against a wide range of diseases. Previously, JA, applied after harvest, was shown to protect sugarbeet roots against the storage pathogens, Botrytis cinerea, P...

  16. Gallic acid-based indanone derivative interacts synergistically with tetracycline by inhibiting efflux pump in multidrug resistant E. coli.

    PubMed

    Dwivedi, Gaurav Raj; Tiwari, Nimisha; Singh, Aastha; Kumar, Akhil; Roy, Sudeep; Negi, Arvind Singh; Pal, Anirban; Chanda, Debabrata; Sharma, Ashok; Darokar, Mahendra P

    2016-03-01

    The purpose of the present study was to study the synergy potential of gallic acid-based derivatives in combination with conventional antibiotics using multidrug resistant cultures of Escherichia coli. Gallic acid-based derivatives significantly reduced the MIC of tetracycline against multidrug resistant clinical isolate of E. coli. The best representative, 3-(3',4,'5'-trimethoxyphenyl)-4,5,6-trimethoxyindanone-1, an indanone derivative of gallic acid, was observed to inhibit ethidium bromide efflux and ATPase which was also supported by in silico docking. This derivative extended the post-antibiotic effect and decreased the mutation prevention concentration of tetracycline. This derivative in combination with TET was able to reduce the concentration of TNFα up to 18-fold in Swiss albino mice. This derivative was nontoxic and well tolerated up to 300 mg/kg dose in subacute oral toxicity study in mice. This is the first report of gallic acid-based indanone derivative as drug resistance reversal agent acting through ATP-dependent efflux pump inhibition.

  17. Oxidized omega-3 fatty acids in fish oil inhibit leukocyte-endothelial interactions through activation of PPAR alpha.

    PubMed

    Sethi, Sanjeev; Ziouzenkova, Ouliana; Ni, Heyu; Wagner, Denisa D; Plutzky, Jorge; Mayadas, Tanya N

    2002-08-15

    Omega-3 fatty acids, which are abundant in fish oil, improve the prognosis of several chronic inflammatory diseases although the mechanism for such effects remains unclear. These fatty acids, such as eicosapentaenoic acid (EPA), are highly polyunsaturated and readily undergo oxidation. We show that oxidized, but not native unoxidized, EPA significantly inhibited human neutrophil and monocyte adhesion to endothelial cells in vitro by inhibiting endothelial adhesion receptor expression. In transcriptional coactivation assays, oxidized EPA potently activated the peroxisome proliferator-activated receptor alpha (PPAR alpha), a member of the nuclear receptor family. In vivo, oxidized, but not native, EPA markedly reduced leukocyte rolling and adhesion to venular endothelium of lipopolysaccharide (LPS)-treated mice. This occurred via a PPAR alpha-dependent mechanism because oxidized EPA had no such effect in LPS-treated PPAR alpha-deficient mice. Therefore, the beneficial effects of omega-3 fatty acids may be explained by a PPAR alpha-mediated anti-inflammatory effect of oxidized EPA. PMID:12149216

  18. Prognostic Significance of Forkhead Box M1 (FOXM1) Expression and Antitumor Effect of FOXM1 Inhibition in Angiosarcoma

    PubMed Central

    Ito, Takamichi; Kohashi, Kenichi; Yamada, Yuichi; Iwasaki, Takeshi; Maekawa, Akira; Kuda, Masaaki; Hoshina, Daichi; Abe, Riichiro; Furue, Masutaka; Oda, Yoshinao

    2016-01-01

    Background: The prognosis of angiosarcoma is poor and a novel treatment option for the disease is desired. The aim of this study was to investigate the prognostic significance of Forkhead box M1 (FOXM1), a transcription factor that regulates cell-cycle progression and various crucial processes in tumor progression, and its potential as a new therapeutic target. Methods: We investigated 125 angiosarcoma clinical samples (94 primary lesions and 31 metastatic lesions in 94 patients) and a human angiosarcoma cell line (HAMON) using immunohistochemical staining and molecular biological approaches. FOXM1 expression in angiosarcoma samples was also compared with that in Kaposi's sarcomas (n = 13), epithelioid hemangioendotheliomas (n = 13) and benign hemangiomas (n = 10). Results: Patients with FOXM1-overexpressing angiosarcoma had significantly shorter survival (both for disease-specific survival [DSS] and event-free survival [EFS]) than other patients (5-year DSS, 23.5% vs. 47.1%, P = 0.013; and 5-year EFS, 5.5% vs. 28.7%, P = 0.004). FOXM1 overexpression was also an independent prognostic factor for both DSS and EFS in Cox multivariate analyses (hazard ratio [HR] 2.84, 95% confidence interval [CI] 1.10-5.81, P = 0.039; and HR 4.16, 95%CI 2.03-8.67, P = 0.0001, respectively). FOXM1 inhibition using both small interfering RNA and a specific inhibitor (thiostrepton) suppressed cell proliferation of the angiosarcoma cell line. Furthermore, FOXM1 inhibition improved the chemosensitivity to docetaxel in vitro. Conclusions: FOXM1 inhibition may be a potential therapeutic option for angiosarcoma. PMID:27162541

  19. In vitro inhibition of salicylic acid derivatives on human cytosolic carbonic anhydrase isozymes I and II.

    PubMed

    Bayram, Esra; Senturk, Murat; Kufrevioglu, O Irfan; Supuran, Claudiu T

    2008-10-15

    The inhibition of two human cytosolic carbonic anhydrase (hCA, EC 4.2.1.1) isozymes, hCA I and II, with a series of salicylic acid derivatives was investigated by using the esterase method with 4-nitrophenyl acetate as substrate. IC(50) values for sulfasalazine, diflunisal, 5-chlorosalicylic acid, dinitrosalicylic acid, 4-aminosalicylic acid, 4-sulfosalicylic acid, 5-sulfosalicylic acid, salicylic acid, acetylsalicylic acid (aspirin) and 3-metylsalicylic acid were of 3.04 microM, 3.38 microM, 4.07 microM, 7.64 microM, 0.13 mM, 0.29 mM, 0.42 mM, 0.56 mM, 2.71 mM and 3.07 mM for hCA I and of 4.49 microM, 2.70 microM, 0.72 microM, 2.80 microM, 0.75 mM, 0.72 mM, 0.29 mM, 0.68 mM, 1.16 mM and 4.70 mM for hCA II, respectively. Lineweaver-Burk plots were also used for the determination of the inhibition mechanism of these substituted phenols, most of which were noncompetitive inhibitors with this substrate. Some salicylic acid derivatives investigated here showed effective hCA I and II inhibitory activity, and might be used as leads for generating enzyme inhibitors eventually targeting other isoforms which have not been assayed yet for their interactions with such agents.

  20. Activation of Exogenous Fatty Acids to Acyl-Acyl Carrier Protein Cannot Bypass FabI Inhibition in Neisseria.

    PubMed

    Yao, Jiangwei; Bruhn, David F; Frank, Matthew W; Lee, Richard E; Rock, Charles O

    2016-01-01

    Neisseria is a Gram-negative pathogen with phospholipids composed of straight chain saturated and monounsaturated fatty acids, the ability to incorporate exogenous fatty acids, and lipopolysaccharides that are not essential. The FabI inhibitor, AFN-1252, was deployed as a chemical biology tool to determine whether Neisseria can bypass the inhibition of fatty acid synthesis by incorporating exogenous fatty acids. Neisseria encodes a functional FabI that was potently inhibited by AFN-1252. AFN-1252 caused a dose-dependent inhibition of fatty acid synthesis in growing Neisseria, a delayed inhibition of growth phenotype, and minimal inhibition of DNA, RNA, and protein synthesis, showing that its mode of action is through inhibiting fatty acid synthesis. Isotopic fatty acid labeling experiments showed that Neisseria encodes the ability to incorporate exogenous fatty acids into its phospholipids by an acyl-acyl carrier protein-dependent pathway. However, AFN-1252 remained an effective antibacterial when Neisseria were supplemented with exogenous fatty acids. These results demonstrate that extracellular fatty acids are activated by an acyl-acyl carrier protein synthetase (AasN) and validate type II fatty acid synthesis (FabI) as a therapeutic target against Neisseria.

  1. Lobaric Acid Inhibits VCAM-1 Expression in TNF-α-Stimulated Vascular Smooth Muscle Cells via Modulation of NF-κB and MAPK Signaling Pathways

    PubMed Central

    Kwon, Ii-Seul; Yim, Joung-Han; Lee, Hong-Kum; Pyo, Suhkneung

    2016-01-01

    Lichens have been known to possess multiple biological activities, including anti-proliferative and anti-inflammatory activities. Vascular cell adhesion molecule-1 (VCAM-1) may play a role in the development of atherosclerosis. Hence, VCAM-1 is a possible therapeutic target in the treatment of the inflammatory disease. However, the effect of lobaric acid on VCAM-1 has not yet been investigated and characterized. For this study, we examined the effect of lobaric acid on the inhibition of VCAM-1 in tumor necrosis factor-alpha (TNF-α)-stimulated mouse vascular smooth muscle cells. Western blot and ELISA showed that the increased expression of VCAM-1 by TNF-α was significantly suppressed by the pre-treatment of lobaric acid (0.1–10 μg/ml) for 2 h. Lobaric acid abrogated TNF-α-induced NF-κB activity through preventing the degradation of IκB and phosphorylation of extracellular signal-regulated kinases (ERK), c-Jun N-terminal kinases (JNK), and p38 mitogen activated protein (MAP) kinase. Lobaric acid also inhibited the expression of TNF-α receptor 1 (TNF-R1). Overall, our results suggest that lobaric acid inhibited VCAM-1 expression through the inhibition of p38, ERK, JNK and NF-κB signaling pathways, and downregulation of TNF-R1 expression. Therefore, it is implicated that lobaric acid may suppress inflammation by altering the physiology of the atherosclerotic lesion. PMID:26759698

  2. Humic acid inhibits HBV-induced autophagosome formation and induces apoptosis in HBV-transfected Hep G2 cells

    PubMed Central

    Pant, Kishor; Yadav, Ajay K.; Gupta, Parul; Rathore, Abhishek Singh; Nayak, Baibaswata; Venugopal, Senthil K.

    2016-01-01

    Hepatitis B Virus (HBV) utilizes several mechanisms to survive in the host cells and one of the main pathways being autophagosome formation. Humic acid (HA), one of the major components of Mineral pitch, is an Ayurvedic medicinal food, commonly used by the people of the Himalayan regions of Nepal and India for various body ailments. We hypothesized that HA could induce cell death and inhibit HBV-induced autophagy in hepatic cells. Incubation of Hep G2.2.1.5 cells (HepG2 cells stably expressing HBV) with HA (100 μM) inhibited both cell proliferation and autophagosome formation significantly, while apoptosis induction was enhanced. Western blot results showed that HA incubation resulted in decreased levels of beclin-1, SIRT-1 and c-myc, while caspase-3 and β-catenin expression were up-regulated. Western blot results showed that HA significantly inhibited the expression of HBx (3-fold with 50 μM and 5-fold with 100 μM) compared to control cells. When HA was incubated with HBx-transfected Hep G2 cells, HBx-induced autophagosome formation and beclin-1 levels were decreased. These data showed that HA induced apoptosis and inhibited HBV-induced autophagosome formation and proliferation in hepatoma cells. PMID:27708347

  3. Inhibition of Long Chain Acyl Coenzyme A Synthetases during Fatty Acid Loading Induces Lipotoxicity in Macrophages

    PubMed Central

    Saraswathi, Viswanathan; Hasty, Alyssa H.

    2009-01-01

    OBJECTIVES Obesity is often associated with hypertriglyceridemia and elevated free fatty acids (FFAs) which are independent risk factors for cardiovascular disease and diabetes. While impairment of cholesterol homeostasis is known to induce toxicity in macrophages, the consequence of altered fatty acid homeostasis is not clear. METHODS AND RESULTS Long chain acyl CoA synthetases (ACSLs) play a critical role in fatty acid homeostasis by channeling fatty acids to diverse metabolic pools. We treated mouse peritoneal macrophages (MPMs) with VLDL or FFAs in the presence of triacsin C, an inhibitor of the three ACSL isoforms present in macrophages. Treatment of macrophages with VLDL and triacsin C resulted in reduced TG accumulation but increased intracellular FFA levels which induced lipotoxicity characterized by induction of apoptosis. Treatment of MPMs with the saturated fatty acid stearic acid in the presence of triacsin C increased intracellular stearic acid and induced apoptosis. Stromal vascular cells collected from high fat diet-fed mice displayed foam cell morphology and exhibited increased mRNA levels of macrophage markers and ACSL1. Importantly, all of these changes were associated with increased FFA level in AT. CONCLUSIONS Inhibition of ACSLs during fatty acid loading results in apoptosis via accumulation of FFAs. Our data have implications in understanding the consequences of dysregulated fatty acid metabolism in macrophages. PMID:19679826

  4. Growth inhibition of Erwinia amylovora and related Erwinia species by neutralized short‑chain fatty acids.

    PubMed

    Konecki, Katrin; Gernold, Marina; Wensing, Annette; Geider, Klaus

    2013-11-01

    Short-chain fatty acids (SCFAs) are used to preserve food and could be a tool for control of fire blight caused by Erwinia amylovora on apple, pear and related rosaceous plants. Neutralized acids were added to buffered growth media at 0.5–75 mM and tested at pHs ranging from 6.8 to 5.5. Particularly at low pH, SCFAs with a chain length exceeding that of acetic acid such as propionic acid were effective growth inhibitors of E. amylovora possibly due to uptake of free acid and its intracellular accumulation. We also observed high inhibition with monochloroacetic acid. An E. billingiae strain was as sensitive to the acids as E. amylovora or E. tasmaniensis. Fire blight symptoms on pear slices were reduced when the slices were pretreated with neutralized propionic acid. Propionic acid is well water soluble and could be applied in orchards as a control agent for fire blight. PMID:24077735

  5. Peptide nucleic acids inhibit growth of Brucella suis in pure culture and in infected murine macrophages

    PubMed Central

    Rajasekaran, Parthiban; Alexander, Jeffry C.; Seleem, Mohamed N.; Jain, Neeta; Sriranganathan, Nammalwar; Wattam, Alice R.; Setubal, João C.; Boyle, Stephen M.

    2012-01-01

    Peptide nucleic acids (PNAs) are single-stranded, synthetic nucleic acid analogues containing a pseudopeptide backbone in place of the phosphodiester sugar–phosphate. When PNAs are covalently linked to cell-penetrating peptides (CPPs) they readily penetrate the bacterial cell envelope, inhibit expression of targeted genes and cause growth inhibition both of Gram-positive and Gram-negative bacteria. However, the effectiveness of PNAs against Brucella, a facultative intracellular bacterial pathogen, was unknown. The susceptibility of a virulent Brucella suis strain to a variety of PNAs was assessed in pure culture as well as in murine macrophages. The studies showed that some of the PNAs targeted to Brucella genes involved in DNA (polA, dnaG, gyrA), RNA (rpoB), cell envelope (asd), fatty acid (kdtA, acpP) and protein (tsf) synthesis inhibit the growth of B. suis in culture and in macrophages after 24 h of treatment. PNA treatment inhibited Brucella growth by interfering with gene expression in a sequence-specific and dose-dependent manner at micromolar concentrations. The most effective PNA in broth culture was that targeting polA at ca. 12 μM. In contrast, in B. suis-infected macrophages, the most effective PNAs were those targeting asd and dnaG at 30 μM; both of these PNAs had little inhibitory effect on Brucella in broth culture. The polA PNA that inhibits wild-type B. suis also inhibits the growth of wild-type Brucella melitensis 16M and Brucella abortus 2308 in culture. This study reveals the potential usefulness of antisense PNA constructs as novel therapeutic agents against intracellular Brucella. PMID:23305655

  6. Ebselen Inhibits Hepatitis C Virus NS3 Helicase Binding to Nucleic Acid and Prevents Viral Replication

    PubMed Central

    2015-01-01

    The hepatitis C virus (HCV) nonstructural protein 3 (NS3) is both a protease, which cleaves viral and host proteins, and a helicase that separates nucleic acid strands, using ATP hydrolysis to fuel the reaction. Many antiviral drugs, and compounds in clinical trials, target the NS3 protease, but few helicase inhibitors that function as antivirals have been reported. This study focuses on the analysis of the mechanism by which ebselen (2-phenyl-1,2-benzisoselenazol-3-one), a compound previously shown to be a HCV antiviral agent, inhibits the NS3 helicase. Ebselen inhibited the abilities of NS3 to unwind nucleic acids, to bind nucleic acids, and to hydrolyze ATP, and about 1 μM ebselen was sufficient to inhibit each of these activities by 50%. However, ebselen had no effect on the activity of the NS3 protease, even at 100 times higher ebselen concentrations. At concentrations below 10 μM, the ability of ebselen to inhibit HCV helicase was reversible, but prolonged incubation of HCV helicase with higher ebselen concentrations led to irreversible inhibition and the formation of covalent adducts between ebselen and all 14 cysteines present in HCV helicase. Ebselen analogues with sulfur replacing the selenium were just as potent HCV helicase inhibitors as ebselen, but the length of the linker between the phenyl and benzisoselenazol rings was critical. Modifications of the phenyl ring also affected compound potency over 30-fold, and ebselen was a far more potent helicase inhibitor than other, structurally unrelated, thiol-modifying agents. Ebselen analogues were also more effective antiviral agents, and they were less toxic to hepatocytes than ebselen. Although the above structure–activity relationship studies suggest that ebselen targets a specific site on NS3, we were unable to confirm binding to either the NS3 ATP binding site or nucleic acid binding cleft by examining the effects of ebselen on NS3 proteins lacking key cysteines. PMID:25126694

  7. Inhibition of Listeria innocua in hummus by a combination of nisin and citric acid.

    PubMed

    Al-Holy, M; Al-Qadiri, H; Lin, M; Rasco, B

    2006-06-01

    The effect of nisin or citric acid or combinations of these two inhibitors on the inactivation of a cocktail of three Listeria innocua strains was investigated in a model brain heart infusion (BHI) broth and hummus (chickpea dip). In BHI broth, citric acid had a limited ability to inhibit L. innocua growth. Nisin initially reduced L. innocua concentrations by about 3 log cycles; however, L. innocua reached concentrations similar to those of the control after 5 days at 22 degrees C. In combination, the effects of 500 IU/ml nisin and 0.2% citric acid were synergistic and resulted in complete elimination of L. innocua in the BHI broth. The inhibition of L. innocua by nisin (500 or 1,000 IU/g), citric acid (0.1, 0.2, or 0.3%), or their combinations also was evaluated in hummus. Citric acid alone did not affect L. innocua growth or the aerobic bacterial plate count. A combination of 1,000 IU/g nisin and 0.3% citric acid was somewhat effective (approximately 1.5-log reduction) in controlling the concentration of L. innocua and the aerobic plate count for up to 6 days. This combination also may be useful, in addition to proper hygienic practices, for minimizing the growth of the pathogen Listeria monocytogenes in hummus. PMID:16786852

  8. Correlation between arachidonic acid oxygenation and luminol-induced chemiluminescence in neutrophils: inhibition by diethyldithiocarbamate.

    PubMed

    Chabannes, B; Perraut, C; El Habib, R; Moliere, P; Pacheco, Y; Lagarde, M

    1997-04-01

    Neutrophils from allergic subjects were hypersensitive to stimulation by low calcium ionophore concentration (0.15 microM), resulting in an increased formation of leukotriene B4 (LTB4), 5S-hydroxy-6,8,11,14-(E,Z,Z,Z)-eicosatetraenoic acid (5-HETE), and other arachidonic acid metabolites through the 5-lipoxygenase pathway. In parallel, luminol-dependent chemiluminescence was also higher in neutrophils from allergic patients at the basal state and after stimulation by calcium ionophore, revealing an enhancement of radical oxygen species and peroxide production. The activity of glutathione peroxidase, the main enzyme responsible for hydroperoxide reduction, was lowered in these cells. Diethyl-dithiocarbamate (DTC) induced a concentration-dependent decrease in chemiluminescence and arachidonic acid metabolism after neutrophil stimulation. These data show that the elevation of arachidonic acid metabolism in neutrophils from allergic patients is strongly correlated with oxidative status. This elevation may be the consequence of an increased cellular hydroperoxide known to activate 5-lipoxygenase (5-LOX) activity and/or an increased arachidonic acid availability, due either to phospholipase A2 (PLA2) activation or inhibition of arachidonate reesterification into phospholipids. Lowering this oxidative status was associated with a concomitant decrease of this metabolism. Our results suggest that the effect of DTC may be the consequence of an inhibition of peroxyl radical and cellular lipid hydroperoxide production. Thus, DTC may modulate arachidonic acid metabolism in neutrophils by modulating the cellular hydroperoxide level.

  9. [(-)-Epigallocatechin gallate, the main constituent of Japanese green tea, inhibits tumor promotion of okadaic acid].

    PubMed

    Yoshizawa, S

    1996-10-01

    (-)-Epigallocatechin gallate (EGCG), the main constituent of green tea, inhibited a tumor promoting activity of okadaic acid in a two-stage carcinogenesis experiment on mouse skin. The group treated with a single application of 100 micrograms 7, 12-dimethylbenz (a) anthracene followed by repeated applications of 1 microgram okadaic acid resulted in 80% of tumor-bearing mice and 4.7 of average numbers of tumors per mouse in week 20. Repeated applications of 5 mg EGCG, prior to okadaic acid, completely inhibited the tumor formation in mice up to week 20. The inhibitory effects of EGCG with two different doses of each application, 1 mg and 5 mg, were dose-dependent. A topical application of 5 mg EGCG immediately reduced the specific binding of [3H]okadaic acid to a particulate fraction of mouse skin to as low as 30% of control. According to the Scatchard analysis, the reduction of specific [3H]okadaic acid binding was mainly due to the reduction of the binding sites, not due to the change of the affinity. The reduction of the specific binding was closely related to the inhibitory effct of EGCG on tumor promotion of okadaic acid. Since EGCG is a non-toxic compound, ingested in green tea in daily life in Japan, EGCG is one of the candidates for practical cancer chemopreventive agents.

  10. Carnosol and carnosic acids from Salvia officinalis inhibit microsomal prostaglandin E2 synthase-1.

    PubMed

    Bauer, Julia; Kuehnl, Susanne; Rollinger, Judith M; Scherer, Olga; Northoff, Hinnak; Stuppner, Hermann; Werz, Oliver; Koeberle, Andreas

    2012-07-01

    Prostaglandin E(2) (PGE(2)), the most relevant eicosanoid promoting inflammation and tumorigenesis, is formed by cyclooxygenases (COXs) and PGE(2) synthases from free arachidonic acid. Preparations of the leaves of Salvia officinalis are commonly used in folk medicine as an effective antiseptic and anti-inflammatory remedy and possess anticancer activity. Here, we demonstrate that a standard ethyl acetate extract of S. officinalis efficiently suppresses the formation of PGE(2) in a cell-free assay by direct interference with microsomal PGE(2) synthase (mPGES)-1. Bioactivity-guided fractionation of the extract yielded closely related fractions that potently suppressed mPGES-1 with IC(50) values between 1.9 and 3.5 μg/ml. Component analysis of these fractions revealed the diterpenes carnosol and carnosic acid as potential bioactive principles inhibiting mPGES-1 activity with IC(50) values of 5.0 μM. Using a human whole-blood assay as a robust cell-based model, carnosic acid, but not carnosol, blocked PGE(2) generation upon stimulation with lipopolysaccharide (IC(50) = 9.3 μM). Carnosic acid neither inhibited the concomitant biosynthesis of other prostanoids [6-keto PGF(1α), 12(S)-hydroxy-5-cis-8,10-trans-heptadecatrienoic acid, and thromboxane B(2)] in human whole blood nor affected the activities of COX-1/2 in a cell-free assay. Together, S. officinalis extracts and its ingredients carnosol and carnosic acid inhibit PGE(2) formation by selectively targeting mPGES-1. We conclude that the inhibitory effect of carnosic acid on PGE(2) formation, observed in the physiologically relevant whole-blood model, may critically contribute to the anti-inflammatory and anticarcinogenic properties of S. officinalis.

  11. Carnosol and Carnosic Acids from Salvia officinalis Inhibit Microsomal Prostaglandin E2 Synthase-1

    PubMed Central

    Bauer, Julia; Kuehnl, Susanne; Rollinger, Judith M.; Scherer, Olga; Northoff, Hinnak; Stuppner, Hermann; Werz, Oliver; Koeberle, Andreas

    2012-01-01

    Prostaglandin E2 (PGE2), the most relevant eicosanoid promoting inflammation and tumorigenesis, is formed by cyclooxygenases (COXs) and PGE2 synthases from free arachidonic acid. Preparations of the leaves of Salvia officinalis are commonly used in folk medicine as an effective antiseptic and anti-inflammatory remedy and possess anticancer activity. Here, we demonstrate that a standard ethyl acetate extract of S. officinalis efficiently suppresses the formation of PGE2 in a cell-free assay by direct interference with microsomal PGE2 synthase (mPGES)-1. Bioactivity-guided fractionation of the extract yielded closely related fractions that potently suppressed mPGES-1 with IC50 values between 1.9 and 3.5 μg/ml. Component analysis of these fractions revealed the diterpenes carnosol and carnosic acid as potential bioactive principles inhibiting mPGES-1 activity with IC50 values of 5.0 μM. Using a human whole-blood assay as a robust cell-based model, carnosic acid, but not carnosol, blocked PGE2 generation upon stimulation with lipopolysaccharide (IC50 = 9.3 μM). Carnosic acid neither inhibited the concomitant biosynthesis of other prostanoids [6-keto PGF1α, 12(S)-hydroxy-5-cis-8,10-trans-heptadecatrienoic acid, and thromboxane B2] in human whole blood nor affected the activities of COX-1/2 in a cell-free assay. Together, S. officinalis extracts and its ingredients carnosol and carnosic acid inhibit PGE2 formation by selectively targeting mPGES-1. We conclude that the inhibitory effect of carnosic acid on PGE2 formation, observed in the physiologically relevant whole-blood model, may critically contribute to the anti-inflammatory and anticarcinogenic properties of S. officinalis. PMID:22511203

  12. Electrographic seizures are significantly reduced by in vivo inhibition of neuronal uptake of extracellular glutamine in rat hippocampus

    PubMed Central

    Kanamori, Keiko; Ross, Brian D.

    2013-01-01

    Summary Rats were given unilateral kainate injection into hippocampal CA3 region, and the effect of chronic electrographic seizures on extracellular glutamine (GLNECF) was examined in those with low and steady levels of extracellular glutamate (GLUECF). GLNECF, collected by microdialysis in awake rats for 5 h, decreased to 62 ± 4.4% of the initial concentration (n = 6). This change correlated with the frequency and magnitude of seizure activity, and occurred in the ipsilateral but not in contralateral hippocampus, nor in kainate-injected rats that did not undergo seizure (n = 6). Hippocampal intracellular GLN did not differ between the Seizure and No-Seizure Groups. These results suggested an intriguing possibility that seizure-induced decrease of GLNECF reflects not decreased GLN efflux into the extracellular fluid, but increased uptake into neurons. To examine this possibility, neuronal uptake of GLNECF was inhibited in vivo by intrahippocampal perfusion of 2-(methylamino)isobutyrate, a competitive and reversible inhibitor of the sodium-coupled neutral amino acid transporter (SNAT) subtypes 1 and 2, as demonstrated by 1.8 ± 0.17 fold elevation of GLNECF (n = 7). The frequency of electrographic seizures during uptake inhibition was reduced to 35 ± 7% (n = 7) of the frequency in pre-perfusion period, and returned to 88 ± 9% in the post-perfusion period. These novel in vivo results strongly suggest that, in this well-established animal model of temporal-lobe epilepsy, the observed seizure-induced decrease of GLNECF reflects its increased uptake into neurons to sustain enhanced glutamatergic epileptiform activity, thereby demonstrating a possible new target for anti-seizure therapies. PMID:24070846

  13. The Weak Acid Preservative Sorbic Acid Inhibits Conidial Germination and Mycelial Growth of Aspergillus niger through Intracellular Acidification

    PubMed Central

    Plumridge, Andrew; Hesse, Stephan J. A.; Watson, Adrian J.; Lowe, Kenneth C.; Stratford, Malcolm; Archer, David B.

    2004-01-01

    The growth of the filamentous fungus Aspergillus niger, a common food spoilage organism, is inhibited by the weak acid preservative sorbic acid (trans-trans-2,4-hexadienoic acid). Conidia inoculated at 105/ml of medium showed a sorbic acid MIC of 4.5 mM at pH 4.0, whereas the MIC for the amount of mycelia at 24 h developed from the same spore inoculum was threefold lower. The MIC for conidia and, to a lesser extent, mycelia was shown to be dependent on the inoculum size. A. niger is capable of degrading sorbic acid, and this ability has consequences for food preservation strategies. The mechanism of action of sorbic acid was investigated using 31P nuclear magnetic resonance (NMR) spectroscopy. We show that a rapid decline in cytosolic pH (pHcyt) by more than 1 pH unit and a depression of vacuolar pH (pHvac) in A. niger occurs in the presence of sorbic acid. The pH gradient over the vacuole completely collapsed as a result of the decline in pHcyt. NMR spectra also revealed that sorbic acid (3.0 mM at pH 4.0) caused intracellular ATP pools and levels of sugar-phosphomonoesters and -phosphodiesters of A. niger mycelia to decrease dramatically, and they did not recover. The disruption of pH homeostasis by sorbic acid at concentrations below the MIC could account for the delay in spore germination and retardation of the onset of subsequent mycelial growth. PMID:15184150

  14. Fatty acid amide hydrolase inhibition for the symptomatic relief of Parkinson's disease.

    PubMed

    Celorrio, Marta; Fernández-Suárez, Diana; Rojo-Bustamante, Estefanía; Echeverry-Alzate, Víctor; Ramírez, María J; Hillard, Cecilia J; López-Moreno, José A; Maldonado, Rafael; Oyarzábal, Julen; Franco, Rafael; Aymerich, María S

    2016-10-01

    Elements of the endocannabinoid system are strongly expressed in the basal ganglia where they suffer profound rearrangements after dopamine depletion. Modulation of the levels of the endocannabinoid 2-arachidonoyl-glycerol by inhibiting monoacylglycerol lipase alters glial phenotypes and provides neuroprotection in a mouse model of Parkinson's disease. In this study, we assessed whether inhibiting fatty acid amide hydrolase could also provide beneficial effects on the time course of this disease. The fatty acid amide hydrolase inhibitor, URB597, was administered chronically to mice treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine and probenecid (MPTPp) over 5weeks. URB597 (1mg/kg) prevented MPTPp induced motor impairment but it did not preserve the dopamine levels in the nigrostriatal pathway or regulate glial cell activation. The symptomatic relief of URB597 was confirmed in haloperidol-induced catalepsy assays, where its anti-cataleptic effects were both blocked by antagonists of the two cannabinoid receptors (CB1 and CB2), and abolished in animals deficient in these receptors. Other fatty acid amide hydrolase inhibitors, JNJ1661010 and TCF2, also had anti-cataleptic properties. Together, these results demonstrate an effect of fatty acid amide hydrolase inhibition on the motor symptoms of Parkinson's disease in two distinct experimental models that is mediated by cannabinoid receptors. PMID:27318096

  15. Fatty acid amide hydrolase inhibition for the symptomatic relief of Parkinson's disease.

    PubMed

    Celorrio, Marta; Fernández-Suárez, Diana; Rojo-Bustamante, Estefanía; Echeverry-Alzate, Víctor; Ramírez, María J; Hillard, Cecilia J; López-Moreno, José A; Maldonado, Rafael; Oyarzábal, Julen; Franco, Rafael; Aymerich, María S

    2016-10-01

    Elements of the endocannabinoid system are strongly expressed in the basal ganglia where they suffer profound rearrangements after dopamine depletion. Modulation of the levels of the endocannabinoid 2-arachidonoyl-glycerol by inhibiting monoacylglycerol lipase alters glial phenotypes and provides neuroprotection in a mouse model of Parkinson's disease. In this study, we assessed whether inhibiting fatty acid amide hydrolase could also provide beneficial effects on the time course of this disease. The fatty acid amide hydrolase inhibitor, URB597, was administered chronically to mice treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine and probenecid (MPTPp) over 5weeks. URB597 (1mg/kg) prevented MPTPp induced motor impairment but it did not preserve the dopamine levels in the nigrostriatal pathway or regulate glial cell activation. The symptomatic relief of URB597 was confirmed in haloperidol-induced catalepsy assays, where its anti-cataleptic effects were both blocked by antagonists of the two cannabinoid receptors (CB1 and CB2), and abolished in animals deficient in these receptors. Other fatty acid amide hydrolase inhibitors, JNJ1661010 and TCF2, also had anti-cataleptic properties. Together, these results demonstrate an effect of fatty acid amide hydrolase inhibition on the motor symptoms of Parkinson's disease in two distinct experimental models that is mediated by cannabinoid receptors.

  16. Arachidonic acid-mediated inhibition of a potassium current in the giant neurons of Aplysia

    SciTech Connect

    Carlson, R.O.

    1990-01-01

    Biochemical and electrophysiological approaches were used to investigate the role of arachidonic acid (AA) in the modulation of an inwardly rectifying potassium current (I{sub R}) in the giant neurons of the marine snail, Aplysia californica. Using ({sup 3}H)AA as tracer, the intracellular free AA pool in Aplysia ganglia was found to be in a state of constant and rapid turnover through deacylation and reacylation of phospholipid, primarily phosphatidyl-inositol. This constant turnover was accompanied by a constant release of free AA and eicosanoids into the extracellular medium. The effects of three pharmacological agents were characterized with regard to AA metabolism in Aplysia ganglia. 4-O-tetra-decanoylphorbol 13-acetate (TPA), an activator of protein kinase C, stimulated liberation of AA from phospholipid, and 4-bromophenacylbromide (BPB), an inhibitor of phospholipate A{sub 2}, inhibited this liberation. Indomethacin at 250 {mu}M was found to inhibit uptake of AA, likely through inhibition of acyl-CoA synthetase. These agents were also found to modulate I{sub R} in ways which were consistent with their biological effects: TPA inhibited I{sub R}, and both BPB and indomethacin stimulated I{sub R} . Modulation of I{sub R} by these substances was found not to involve cAMP metabolism. Acute application of exogenous AA did not affect I{sub R}; however, I{sub R} in giant neurons was found to be inhibited after dialysis with AA or other unsaturated fatty acids. Also, after perfusion with BSA overnight, a treatment which strips the giant neurons of AA in lipid storage, I{sub R} was found to have increased over 2-fold. This perfusion-induced increase was inhibited by the presence of AA or by pretreatment of the giant neurons with BPB. These results suggest AA, provided through constant turnover from phospholipid, mediates constitutive inhibition of I{sub R}.

  17. Inhibition of metallo-beta-lactamases by a series of mercaptoacetic acid thiol ester derivatives.

    PubMed Central

    Payne, D J; Bateson, J H; Gasson, B C; Proctor, D; Khushi, T; Farmer, T H; Tolson, D A; Bell, D; Skett, P W; Marshall, A C; Reid, R; Ghosez, L; Combret, Y; Marchand-Brynaert, J

    1997-01-01

    A series of mercaptoacetic acid thiol esters have been identified as metallo-beta-lactamase inhibitors. Electrospray mass spectrometry (ESMS) has shown that irreversible inhibition of the Bacillus cereus II metallo-beta-lactamase by SB214751, SB214752, and SB213079 was concomitant with a 90-Da increase in mass of the enzyme. Tryptic digestion of the B. cereus II inhibited with SB214751 illustrated that the peptide fragment, containing the only cysteine of the enzyme, had undergone a mass increment of 90 Da. It was further demonstrated that B. cereus II hydrolyzed this type of compound across the thiol ester bond to yield mercaptoacetic acid. Mercaptoacetic acid is the only molecular fragment common to SB214751, SB214752, and SB213079, and free mercaptoacetic acid does not bind covalently to B. cereus II. Therefore, it is concluded that these compounds inhibit B. cereus II by the mechanism-based delivery of mercaptoacetic acid, forming a disulfide linkage with the active sites cysteine (predicted mass shift = +90 Da) under the aerobic conditions of the assay. The different thiol esters examined had a broad range of potencies against the metallo-beta-lactamases tested. For example SB214751, SB214752, and SB213079 all had 50% inhibitory concentrations of < 10 and > 1,000 microM for the Stenotrophomonas maltophilia L-1 and Bacteroides fragilis CfiA enzymes, respectively. SB216968 was particularly active against the Aeromonas hydrophila CphA metallo-beta-lactamase and was found to be an uncompetitive inhibitor of this enzyme (Ki = 3.9 microM), whereas it exhibited irreversible inhibition of the L-1 enzyme. These observations with this series of compounds have revealed subtle differences between the active sites of different metallo-beta-lactamases. Finally, a novel application for isothermal titration calorimetry for assessing the zinc chelating activity of candidate inhibitors is also presented. PMID:8980769

  18. A novel sea anemone peptide that inhibits acid-sensing ion channels.

    PubMed

    Rodríguez, Armando Alexei; Salceda, Emilio; Garateix, Anoland Georgina; Zaharenko, André Junqueira; Peigneur, Steve; López, Omar; Pons, Tirso; Richardson, Michael; Díaz, Maylín; Hernández, Yasnay; Ständker, Ludger; Tytgat, Jan; Soto, Enrique

    2014-03-01

    Sea anemones produce ion channels peptide toxins of pharmacological and biomedical interest. However, peptides acting on ligand-gated ion channels, including acid-sensing ion channel (ASIC) toxins, remain poorly explored. PhcrTx1 is the first compound characterized from the sea anemone Phymanthus crucifer, and it constitutes a novel ASIC inhibitor. This peptide was purified by gel filtration, ion-exchange and reversed-phase chromatography followed by biological evaluation on ion channels of isolated rat dorsal root ganglia (DRG) neurons using patch clamp techniques. PhcrTx1 partially inhibited ASIC currents (IC50∼100 nM), and also voltage-gated K(+) currents but the effects on the peak and on the steady state currents were lower than 20% in DRG neurons, at concentrations in the micromolar range. No significant effect was observed on Na(+) voltage-gated currents in DRG neurons. The N-terminal sequencing yielded 32 amino acid residues, with a molecular mass of 3477 Da by mass spectrometry. No sequence identity to other sea anemone peptides was found. Interestingly, the bioinformatic analysis of Cys-pattern and secondary structure arrangement suggested that this peptide presents an Inhibitor Cystine Knot (ICK) scaffold, which has been found in other venomous organisms such as spider, scorpions and cone snails. Our results show that PhcrTx1 represents the first member of a new structural group of sea anemones toxins acting on ASIC and, with much lower potency, on Kv channels. Moreover, this is the first report of an ICK peptide in cnidarians, suggesting that the occurrence of this motif in venomous animals is more ancient than expected.

  19. Extracts of Morus nigra L. Leaves Standardized in Chlorogenic Acid, Rutin and Isoquercitrin: Tyrosinase Inhibition and Cytotoxicity

    PubMed Central

    Fontes, Pedro Ribeiro; Souza, Paula Monteiro; William Fagg, Christopher; Neves Silva Guerra, Eliete; de Medeiros Nóbrega, Yanna Karla; Silveira, Damaris; Fonseca-Bazzo, Yris; Simeoni, Luiz Alberto; Homem-de-Mello, Maurício; Oliveira Magalhães, Pérola

    2016-01-01

    Melanogenesis is a process responsible for melanin production, which is stored in melanocytes containing tyrosinase. Inhibition of this enzyme is a target in the cosmetics industry, since it controls undesirable skin conditions such as hyperpigmentation due to the overproduction of melanin. Species of the Morus genus are known for the beneficial uses offered in different parts of its plants, including tyrosinase inhibition. Thus, this project aimed to study the inhibitory activity of tyrosinase by extracts from Morus nigra leaves as well as the characterization of its chromatographic profile and cytotoxicity in order to become a new therapeutic option from a natural source. M. nigra leaves were collected, pulverized, equally divided into five batches and the standardized extract was obtained by passive maceration. There was no significant difference between batches for total solids content, yield and moisture content, which shows good reproducibility of the extraction process. Tyrosinase enzymatic activity was determined for each batch, providing the percentage of enzyme inhibition and IC50 values obtained by constructing dose-response curves and compared to kojic acid, a well-known tyrosinase inhibitor. High inhibition of tyrosinase activity was observed (above 90% at 15.625 μg/mL). The obtained IC50 values ranged from 5.00 μg/mL ± 0.23 to 8.49 μg/mL ± 0.59 and were compared to kojic acid (3.37 μg/mL ± 0.65). High Performance Liquid Chromatography analysis revealed the presence of chlorogenic acid, rutin and, its major compound, isoquercitrin. The chromatographic method employed was validated according to ICH guidelines and the extract was standardized using these polyphenols as markers. Cytotoxicity, assessed by MTT assay, was not observed on murine melanomas, human keratinocytes and mouse fibroblasts in tyrosinase IC50 values. This study demonstrated the potential of M. nigra leaf extract as a promising whitening agent of natural source against skin

  20. Inhibition of Receptor Interacting Protein Kinases Attenuates Cardiomyocyte Hypertrophy Induced by Palmitic Acid.

    PubMed

    Zhao, Mingyue; Lu, Lihui; Lei, Song; Chai, Hua; Wu, Siyuan; Tang, Xiaoju; Bao, Qinxue; Chen, Li; Wu, Wenchao; Liu, Xiaojing

    2016-01-01

    Palmitic acid (PA) is known to cause cardiomyocyte dysfunction. Cardiac hypertrophy is one of the important pathological features of PA-induced lipotoxicity, but the mechanism by which PA induces cardiomyocyte hypertrophy is still unclear. Therefore, our study was to test whether necroptosis, a receptor interacting protein kinase 1 and 3 (RIPK1 and RIPK3-) dependent programmed necrosis, was involved in the PA-induced cardiomyocyte hypertrophy. We used the PA-treated primary neonatal rat cardiac myocytes (NCMs) or H9c2 cells to study lipotoxicity. Our results demonstrated that cardiomyocyte hypertrophy was induced by PA treatment, determined by upregulation of hypertrophic marker genes and cell surface area enlargement. Upon PA treatment, the expression of RIPK1 and RIPK3 was increased. Pretreatment with the RIPK1 inhibitor necrostatin-1 (Nec-1), the PA-induced cardiomyocyte hypertrophy, was attenuated. Knockdown of RIPK1 or RIPK3 by siRNA suppressed the PA-induced myocardial hypertrophy. Moreover, a crosstalk between necroptosis and endoplasmic reticulum (ER) stress was observed in PA-treated cardiomyocytes. Inhibition of RIPK1 with Nec-1, phosphorylation level of AKT (Ser473), and mTOR (Ser2481) was significantly reduced in PA-treated cardiomyocytes. In conclusion, RIPKs-dependent necroptosis might be crucial in PA-induced myocardial hypertrophy. Activation of mTOR may mediate the effect of necroptosis in cardiomyocyte hypertrophy induced by PA. PMID:27057269

  1. Corosolic acid ameliorates acute inflammation through inhibition of IRAK-1 phosphorylation in macrophages

    PubMed Central

    Kim, Seung-Jae; Cha, Ji-Young; Kang, Hye Suk; Lee, Jae-Ho; Lee, Ji Yoon; Park, Jae-Hyung; Bae, Jae-Hoon; Song, Dae-Kyu; Im, Seung-Soon

    2016-01-01

    Corosolic acid (CA), a triterpenoid compound isolated from Lagerstroemia speciosa L. (Banaba) leaves, exerts anti-inflammatory effects by regulating phosphorylation of interleukin receptor- associated kinase (IRAK)-2 via the NF-κB cascade. However, the protective effect of CA against endotoxic shock has not been reported. LPS (200 ng/mL, 30 min) induced phosphorylation of IRAK-1 and treatment with CA (10 μM) significantly attenuated this effect. In addition, CA also reduced protein levels of NLRP3 and ASC which are the main components of the inflammasome in BMDMs. LPS-induced inflammasome assembly through activation of IRAK-1 was down-regulated by CA challenge. Treatment with Bay11-7082, an inhibitor of IκB-α, had no effect on CA-mediated inhibition of IRAK-1 activation, indicating that CA-mediated attenuation of IRAK-1 phosphorylation was independent of NF-κB signaling. These results demonstrate that CA ameliorates acute inflammation in mouse BMDMs and CA may be useful as a pharmacological agent to prevent acute inflammation. [BMB Reports 2016; 49(5): 276-281] PMID:26615974

  2. Pancreatic spasmolytic polypeptide protects the gastric mucosa but does not inhibit acid secretion or motility.

    PubMed

    McKenzie, C; Marchbank, T; Playford, R J; Otto, W; Thim, L; Parsons, M E

    1997-07-01

    The objectives of these studies were to examine whether the trefoil peptide porcine pancreatic spasmolytic polypeptide (PSP) had gastric mucosal protectant properties similar to its human equivalent human spasmolytic polypeptide (hSP) and to confirm the antisecretory and antimotility action of the peptide. PSP and recombinant hSP reduced gastric mucosal damage caused by a combination of subcutaneous indomethacin and restraint stress in the conscious rat. At a dose of 500 micrograms/kg bolus plus 500 micrograms.kg-1.h-1 sc, PSP significantly reduced the total area of damage by 58%. PSP at a dose of 150 micrograms/kg iv had no inhibitory effect on pentagastrin-stimulated gastric acid secretion in the perfused stomachs of anesthetized rats. This lack of antisecretory activity was confirmed in vitro using an isolated stomach preparation from the immature rat. PSP and hSP at concentrations up to 800 nM did not inhibit electrically or chemically evoked contractions of the guinea pig ileum and duodenum in vitro. Thus antisecretory and antimotility actions do not underlie the mucosal protectant properties of PSP. PSP did, however, stimulate cell migration, and this may, at least in part, account for its protectant properties.

  3. The chemotaxonomic significance of two bioactive caffeic acid esters, nepetoidins A and B, in the Lamiaceae.

    PubMed

    Grayer, Renée J; Eckert, Maria R; Veitch, Nigel C; Kite, Geoffrey C; Marin, Petar D; Kokubun, Tetsuo; Simmonds, Monique S J; Paton, Alan J

    2003-09-01

    A survey of leaf surface constituents in the family Lamiaceae using HPLC with diode array detection revealed the presence of two characteristic phenolic compounds in many species. The distribution of these phenolics in the Lamiaceae was found to be of taxonomic significance, as they were present in the great majority of species investigated for the subfamily Nepetoideae, including representatives of the well-known genera of culinary herbs, mint, rosemary, sage, thyme and basil. In contrast, they were absent from species of the other subfamilies of Lamiaceae studied and from the related families Verbenaceae, Scrophulariaceae, Acanthaceae and Buddlejaceae. The compounds were isolated from Plectranthus crassus and identified by NMR spectroscopy as the known caffeic acid esters (Z,E)-[2-(3,5-dihydroxyphenyl)ethenyl] 3-(3,4-dihydroxyphenyl)-2-propenoate and (Z,E)-[2-(3,4-dihydroxyphenyl)ethenyl] 3-(3,4-dihydroxyphenyl)-2-propenoate, for which the trivial names nepetoidins A and B are proposed. The presence of this pair of caffeic acid esters adds another character to the chemical, palynological and embryological features distinguishing the Nepetoideae from the other subfamilies of Lamiaceae and related families, and supports the view that the Nepetoideae are a specialised and monophyletic group within the family. Nepetoidin B was shown to have a greater antioxidant activity than gallic, rosmarinic and caffeic acids, and showed activity as an insect phagostimulant. Both compounds were antifungal.

  4. Inhibition of fungal spore adhesion by zosteric Acid as the basis for a novel, nontoxic crop protection technology.

    PubMed

    Stanley, Michele S; Callow, Maureen E; Perry, Ruth; Alberte, Randall S; Smith, Robert; Callow, James A

    2002-04-01

    ABSTRACT To explore the potential for nontoxic crop protection technologies based on the inhibition of fungal spore adhesion, we have tested the effect of synthetic zosteric acid (p-(sulfo-oxy) cinnamic acid), a naturally occurring phenolic acid in eelgrass (Zostera marina L.) plants, on spore adhesion and infection in two pathosystems: rice blast caused by Magnaporthe grisea and bean anthracnose caused by Colletotrichum lindemuthianum. We have shown that zosteric acid inhibits spore adhesion to model and host leaf surfaces and that any attached spores fail to develop appressoria, and consequently do not infect leaf cells. Low concentrations of zosteric acid that are effective in inhibiting adhesion are not toxic to either fungus or to the host. The inhibition of spore adhesion in the rice blast pathogen is fully reversible. On plants, zosteric acid reduced (rice) or delayed (bean) lesion development. These results suggest that there is potential for novel and environmentally benign crop protection technologies based on manipulating adhesion.

  5. Transferrin-Targeted Nanoparticles Containing Zoledronic Acid as a Potential Tool to Inhibit Glioblastoma Growth.

    PubMed

    Salzano, G; Zappavigna, S; Luce, A; D'Onofrio, N; Balestrieri, M L; Grimaldi, A; Lusa, S; Ingrosso, D; Artuso, S; Porru, M; Leonetti, C; Caraglia, M; De Rosa, G

    2016-04-01

    The treatment of glioblastoma (GBM) is a challenge for the biomedical research since cures remain elusive. Its current therapy, consisted on surgery, radiotherapy, and concomitant chemotherapy with temozolomide (TMZ), is often uneffective. Here, we proposed the use of zoledronic acid (ZOL) as a potential agent for the treatment of GBM. Our group previously developed self-assembling nanoparticles, also named PLCaPZ NPs, to use ZOL in the treatment of prostate cancer. Here, we updated the previously developed nanoparticles (NPs) by designing transferrin (Tf)-targeted self-assembling NPs, also named Tf-PLCaPZ NPs, to use ZOL in the treatment of brain tumors, e.g., GBM. The efficacy of Tf-PLCaPZ NPs was evaluated in different GBM cell lines and in an animal model of GBM, in comparison with PLCaPZ NPs and free ZOL. Tf-PLCaPZ NPs were characterized by a narrow size distribution and a high incorporation efficiency of ZOL. Moreover, the presence of Tf significantly reduced the hemolytic activity of the formulation. In vitro, in LN229 cells, a significant uptake and cell growth inhibition after treatment with Tf-PLCaPZ NPs was achieved. Moreover, the sequential therapy of TMZ and Tf-PLCaPZ NPs lead to a superior therapeutic activity compared to their single administration. The results obtained in mice xenografted with U373MG, revealed a significant anticancer activity of Tf-PLCaPZ NPs, while the tumors remained unaffected with free TMZ. These promising results introduce a novel type of easy-to-obtain NPs for the delivery of ZOL in the treatment of GBM tumors.

  6. Transferrin-Targeted Nanoparticles Containing Zoledronic Acid as a Potential Tool to Inhibit Glioblastoma Growth.

    PubMed

    Salzano, G; Zappavigna, S; Luce, A; D'Onofrio, N; Balestrieri, M L; Grimaldi, A; Lusa, S; Ingrosso, D; Artuso, S; Porru, M; Leonetti, C; Caraglia, M; De Rosa, G

    2016-04-01

    The treatment of glioblastoma (GBM) is a challenge for the biomedical research since cures remain elusive. Its current therapy, consisted on surgery, radiotherapy, and concomitant chemotherapy with temozolomide (TMZ), is often uneffective. Here, we proposed the use of zoledronic acid (ZOL) as a potential agent for the treatment of GBM. Our group previously developed self-assembling nanoparticles, also named PLCaPZ NPs, to use ZOL in the treatment of prostate cancer. Here, we updated the previously developed nanoparticles (NPs) by designing transferrin (Tf)-targeted self-assembling NPs, also named Tf-PLCaPZ NPs, to use ZOL in the treatment of brain tumors, e.g., GBM. The efficacy of Tf-PLCaPZ NPs was evaluated in different GBM cell lines and in an animal model of GBM, in comparison with PLCaPZ NPs and free ZOL. Tf-PLCaPZ NPs were characterized by a narrow size distribution and a high incorporation efficiency of ZOL. Moreover, the presence of Tf significantly reduced the hemolytic activity of the formulation. In vitro, in LN229 cells, a significant uptake and cell growth inhibition after treatment with Tf-PLCaPZ NPs was achieved. Moreover, the sequential therapy of TMZ and Tf-PLCaPZ NPs lead to a superior therapeutic activity compared to their single administration. The results obtained in mice xenografted with U373MG, revealed a significant anticancer activity of Tf-PLCaPZ NPs, while the tumors remained unaffected with free TMZ. These promising results introduce a novel type of easy-to-obtain NPs for the delivery of ZOL in the treatment of GBM tumors. PMID:27301207

  7. Inhibition of retinoic acid biosynthesis by the bisdichloroacetyldiamine WIN 18,446 markedly suppresses spermatogenesis and alters retinoid metabolism in mice.

    PubMed

    Paik, Jisun; Haenisch, Michael; Muller, Charles H; Goldstein, Alex S; Arnold, Samuel; Isoherranen, Nina; Brabb, Thea; Treuting, Piper M; Amory, John K

    2014-05-23

    Knowledge of the regulation of testicular retinoic acid synthesis is crucial for understanding its role in spermatogenesis. Bisdichloroacetyldiamines strongly inhibit spermatogenesis. We reported previously that one of these compounds, WIN 18,446, potently inhibited spermatogenesis in rabbits by inhibiting retinoic acid synthesis. To understand how WIN 18,446 inhibits retinoic acid synthesis, we characterized its effects on human retinal dehydrogenase ALDH1A2 in vitro as well as its effects on retinoid metabolism in vivo using mice. WIN 18,446 strongly and irreversibly inhibited ALDH1A2 in vitro. In vivo, WIN 18,446 treatment completely abolished spermatogenesis after 4 weeks of treatment and modestly reduced adiposity in mice fed a chow diet. Effects of WIN 18,446 on retinoid concentrations were tissue-dependent. Although lung and liver retinyl ester concentrations were lower in WIN 18,446-treated animals, adipose retinyl ester levels were increased following the treatment. Interestingly, animals treated with WIN 18,446 had significantly higher circulating retinol concentrations compared with control mice. The effect on spermatogenesis by WIN 18,446 was not prevented by simultaneous treatment with retinoic acid, whereas effects on other tissues were partially or completely reversed. Cessation of WIN 18,446 treatment for 4 weeks reversed most retinoid-related phenotypes except for inhibition of spermatogenesis. Our data suggest that WIN 18,446 may be a useful model of systemic acquired retinoic acid deficiency. Given the effects observed in our study, inhibition of retinoic acid biosynthesis may have relevance for the treatment of obesity and in the development of novel male contraceptives.

  8. Inhibition of Retinoic Acid Biosynthesis by the Bisdichloroacetyldiamine WIN 18,446 Markedly Suppresses Spermatogenesis and Alters Retinoid Metabolism in Mice*

    PubMed Central

    Paik, Jisun; Haenisch, Michael; Muller, Charles H.; Goldstein, Alex S.; Arnold, Samuel; Isoherranen, Nina; Brabb, Thea; Treuting, Piper M.; Amory, John K.

    2014-01-01

    Knowledge of the regulation of testicular retinoic acid synthesis is crucial for understanding its role in spermatogenesis. Bisdichloroacetyldiamines strongly inhibit spermatogenesis. We reported previously that one of these compounds, WIN 18,446, potently inhibited spermatogenesis in rabbits by inhibiting retinoic acid synthesis. To understand how WIN 18,446 inhibits retinoic acid synthesis, we characterized its effects on human retinal dehydrogenase ALDH1A2 in vitro as well as its effects on retinoid metabolism in vivo using mice. WIN 18,446 strongly and irreversibly inhibited ALDH1A2 in vitro. In vivo, WIN 18,446 treatment completely abolished spermatogenesis after 4 weeks of treatment and modestly reduced adiposity in mice fed a chow diet. Effects of WIN 18,446 on retinoid concentrations were tissue-dependent. Although lung and liver retinyl ester concentrations were lower in WIN 18,446-treated animals, adipose retinyl ester levels were increased following the treatment. Interestingly, animals treated with WIN 18,446 had significantly higher circulating retinol concentrations compared with control mice. The effect on spermatogenesis by WIN 18,446 was not prevented by simultaneous treatment with retinoic acid, whereas effects on other tissues were partially or completely reversed. Cessation of WIN 18,446 treatment for 4 weeks reversed most retinoid-related phenotypes except for inhibition of spermatogenesis. Our data suggest that WIN 18,446 may be a useful model of systemic acquired retinoic acid deficiency. Given the effects observed in our study, inhibition of retinoic acid biosynthesis may have relevance for the treatment of obesity and in the development of novel male contraceptives. PMID:24711451

  9. Marine organism sulfated polysaccharides exhibiting significant antimalarial activity and inhibition of red blood cell invasion by Plasmodium.

    PubMed

    Marques, Joana; Vilanova, Eduardo; Mourão, Paulo A S; Fernàndez-Busquets, Xavier

    2016-01-01

    The antimalarial activity of heparin, against which there are no resistances known, has not been therapeutically exploited due to its potent anticoagulating activity. Here, we have explored the antiplasmodial capacity of heparin-like sulfated polysaccharides from the sea cucumbers Ludwigothurea grisea and Isostichopus badionotus, from the red alga Botryocladia occidentalis, and from the marine sponge Desmapsamma anchorata. In vitro experiments demonstrated for most compounds significant inhibition of Plasmodium falciparum growth at low-anticoagulant concentrations. This activity was found to operate through inhibition of erythrocyte invasion by Plasmodium, likely mediated by a coating of the parasite similar to that observed for heparin. In vivo four-day suppressive tests showed that several of the sulfated polysaccharides improved the survival of Plasmodium yoelii-infected mice. In one animal treated with I. badionotus fucan parasitemia was reduced from 10.4% to undetectable levels, and Western blot analysis revealed the presence of antibodies against P. yoelii antigens in its plasma. The retarded invasion mediated by sulfated polysaccharides, and the ensuing prolonged exposure of Plasmodium to the immune system, can be explored for the design of new therapeutic approaches against malaria where heparin-related polysaccharides of low anticoagulating activity could play a dual role as drugs and as potentiators of immune responses. PMID:27071342

  10. Marine organism sulfated polysaccharides exhibiting significant antimalarial activity and inhibition of red blood cell invasion by Plasmodium

    PubMed Central

    Marques, Joana; Vilanova, Eduardo; Mourão, Paulo A. S.; Fernàndez-Busquets, Xavier

    2016-01-01

    The antimalarial activity of heparin, against which there are no resistances known, has not been therapeutically exploited due to its potent anticoagulating activity. Here, we have explored the antiplasmodial capacity of heparin-like sulfated polysaccharides from the sea cucumbers Ludwigothurea grisea and Isostichopus badionotus, from the red alga Botryocladia occidentalis, and from the marine sponge Desmapsamma anchorata. In vitro experiments demonstrated for most compounds significant inhibition of Plasmodium falciparum growth at low-anticoagulant concentrations. This activity was found to operate through inhibition of erythrocyte invasion by Plasmodium, likely mediated by a coating of the parasite similar to that observed for heparin. In vivo four-day suppressive tests showed that several of the sulfated polysaccharides improved the survival of Plasmodium yoelii-infected mice. In one animal treated with I. badionotus fucan parasitemia was reduced from 10.4% to undetectable levels, and Western blot analysis revealed the presence of antibodies against P. yoelii antigens in its plasma. The retarded invasion mediated by sulfated polysaccharides, and the ensuing prolonged exposure of Plasmodium to the immune system, can be explored for the design of new therapeutic approaches against malaria where heparin-related polysaccharides of low anticoagulating activity could play a dual role as drugs and as potentiators of immune responses. PMID:27071342

  11. Specific amino acids inhibit food intake via the area postrema or vagal afferents.

    PubMed

    Jordi, Josua; Herzog, Brigitte; Camargo, Simone M R; Boyle, Christina N; Lutz, Thomas A; Verrey, François

    2013-11-15

    To maintain nutrient homeostasis the central nervous system integrates signals that promote or inhibit eating. The supply of vital amino acids is tuned by adjusting food intake according to its dietary protein content. We hypothesized that this effect is based on the sensing of individual amino acids as a signal to control food intake. Here, we show that food intake was most potently reduced by oral L-arginine (Arg), L-lysine (Lys) and L-glutamic acid (Glu) compared to all other 17 proteogenic amino acids in rats. These three amino acids induced neuronal activity in the area postrema and the nucleus of the solitary tract. Surgical lesion of the area postrema abolished the anorectic response to Arg and Glu, whereas vagal afferent lesion prevented the response to Lys. These three amino acids also provoked gastric distension by differentially altering gastric secretion and/or emptying. Importantly, these peripheral mechanical vagal stimuli were dissociated from the amino acids' effect on food intake. Thus, Arg, Lys and Glu had a selective impact on food processing and intake suggesting them as direct sensory input to assess dietary protein content and quality in vivo. Overall, this study reveals novel amino acid-specific mechanisms for the control of food intake and of gastrointestinal function.

  12. Dipeptidyl peptidase IV inhibition potentiates amino acid- and bile acid-induced bicarbonate secretion in rat duodenum.

    PubMed

    Inoue, Takuya; Wang, Joon-Ho; Higashiyama, Masaaki; Rudenkyy, Sergiy; Higuchi, Kazuhide; Guth, Paul H; Engel, Eli; Kaunitz, Jonathan D; Akiba, Yasutada

    2012-10-01

    Intestinal endocrine cells release gut hormones, including glucagon-like peptides (GLPs), in response to luminal nutrients. Luminal L-glutamate (L-Glu) and 5'-inosine monophosphate (IMP) synergistically increases duodenal HCO3- secretion via GLP-2 release. Since L cells express the bile acid receptor TGR5 and dipeptidyl peptidase (DPP) IV rapidly degrades GLPs, we hypothesized that luminal amino acids or bile acids stimulate duodenal HCO3- secretion via GLP-2 release, which is enhanced by DPPIV inhibition. We measured HCO3- secretion with pH and CO2 electrodes using a perfused rat duodenal loop under isoflurane anesthesia. L-Glu (10 mM) and IMP (0.1 mM) were luminally coperfused with or without luminal perfusion (0.1 mM) or intravenous (iv) injection (3 μmol/kg) of the DPPIV inhibitor NVP728. The loop was also perfused with a selective TGR5 agonist betulinic acid (BTA, 10 μM) or the non-bile acid type TGR5 agonist 3-(2-chlorophenyl)-N-(4-chlorophenyl)-N,5-dimethylisoxazole-4-carboxamide (CCDC; 10 μM). DPPIV activity visualized by use of the fluorogenic substrate was present on the duodenal brush border and submucosal layer, both abolished by the incubation with NVP728 (0.1 mM). An iv injection of NVP728 enhanced L-Glu/IMP-induced HCO3- secretion, whereas luminal perfusion of NVP728 had no effect. BTA or CCDC had little effect on HCO3- secretion, whereas NVP728 iv markedly enhanced BTA- or CCDC-induced HCO3- secretion, the effects inhibited by a GLP-2 receptor antagonist. Coperfusion of the TGR5 agonist enhanced L-Glu/IMP-induced HCO3- secretion with the enhanced GLP-2 release, suggesting that TGR5 activation amplifies nutrient sensing signals. DPPIV inhibition potentiated luminal L-Glu/IMP-induced and TGR5 agonist-induced HCO3- secretion via a GLP-2 pathway, suggesting that the modulation of the local concentration of the endogenous secretagogue GLP-2 by luminal compounds and DPPIV inhibition helps regulate protective duodenal HCO3- secretion.

  13. Dipeptidyl peptidase IV inhibition potentiates amino acid- and bile acid-induced bicarbonate secretion in rat duodenum

    PubMed Central

    Inoue, Takuya; Wang, Joon-Ho; Higashiyama, Masaaki; Rudenkyy, Sergiy; Higuchi, Kazuhide; Guth, Paul H.; Engel, Eli; Kaunitz, Jonathan D.

    2012-01-01

    Intestinal endocrine cells release gut hormones, including glucagon-like peptides (GLPs), in response to luminal nutrients. Luminal l-glutamate (l-Glu) and 5′-inosine monophosphate (IMP) synergistically increases duodenal HCO3− secretion via GLP-2 release. Since L cells express the bile acid receptor TGR5 and dipeptidyl peptidase (DPP) IV rapidly degrades GLPs, we hypothesized that luminal amino acids or bile acids stimulate duodenal HCO3− secretion via GLP-2 release, which is enhanced by DPPIV inhibition. We measured HCO3− secretion with pH and CO2 electrodes using a perfused rat duodenal loop under isoflurane anesthesia. l-Glu (10 mM) and IMP (0.1 mM) were luminally coperfused with or without luminal perfusion (0.1 mM) or intravenous (iv) injection (3 μmol/kg) of the DPPIV inhibitor NVP728. The loop was also perfused with a selective TGR5 agonist betulinic acid (BTA, 10 μM) or the non-bile acid type TGR5 agonist 3-(2-chlorophenyl)-N-(4-chlorophenyl)-N,5-dimethylisoxazole-4-carboxamide (CCDC; 10 μM). DPPIV activity visualized by use of the fluorogenic substrate was present on the duodenal brush border and submucosal layer, both abolished by the incubation with NVP728 (0.1 mM). An iv injection of NVP728 enhanced l-Glu/IMP-induced HCO3− secretion, whereas luminal perfusion of NVP728 had no effect. BTA or CCDC had little effect on HCO3− secretion, whereas NVP728 iv markedly enhanced BTA- or CCDC-induced HCO3− secretion, the effects inhibited by a GLP-2 receptor antagonist. Coperfusion of the TGR5 agonist enhanced l-Glu/IMP-induced HCO3− secretion with the enhanced GLP-2 release, suggesting that TGR5 activation amplifies nutrient sensing signals. DPPIV inhibition potentiated luminal l-Glu/IMP-induced and TGR5 agonist-induced HCO3− secretion via a GLP-2 pathway, suggesting that the modulation of the local concentration of the endogenous secretagogue GLP-2 by luminal compounds and DPPIV inhibition helps regulate protective duodenal HCO3− secretion

  14. Dipeptidyl peptidase IV inhibition potentiates amino acid- and bile acid-induced bicarbonate secretion in rat duodenum.

    PubMed

    Inoue, Takuya; Wang, Joon-Ho; Higashiyama, Masaaki; Rudenkyy, Sergiy; Higuchi, Kazuhide; Guth, Paul H; Engel, Eli; Kaunitz, Jonathan D; Akiba, Yasutada

    2012-10-01

    Intestinal endocrine cells release gut hormones, including glucagon-like peptides (GLPs), in response to luminal nutrients. Luminal L-glutamate (L-Glu) and 5'-inosine monophosphate (IMP) synergistically increases duodenal HCO3- secretion via GLP-2 release. Since L cells express the bile acid receptor TGR5 and dipeptidyl peptidase (DPP) IV rapidly degrades GLPs, we hypothesized that luminal amino acids or bile acids stimulate duodenal HCO3- secretion via GLP-2 release, which is enhanced by DPPIV inhibition. We measured HCO3- secretion with pH and CO2 electrodes using a perfused rat duodenal loop under isoflurane anesthesia. L-Glu (10 mM) and IMP (0.1 mM) were luminally coperfused with or without luminal perfusion (0.1 mM) or intravenous (iv) injection (3 μmol/kg) of the DPPIV inhibitor NVP728. The loop was also perfused with a selective TGR5 agonist betulinic acid (BTA, 10 μM) or the non-bile acid type TGR5 agonist 3-(2-chlorophenyl)-N-(4-chlorophenyl)-N,5-dimethylisoxazole-4-carboxamide (CCDC; 10 μM). DPPIV activity visualized by use of the fluorogenic substrate was present on the duodenal brush border and submucosal layer, both abolished by the incubation with NVP728 (0.1 mM). An iv injection of NVP728 enhanced L-Glu/IMP-induced HCO3- secretion, whereas luminal perfusion of NVP728 had no effect. BTA or CCDC had little effect on HCO3- secretion, whereas NVP728 iv markedly enhanced BTA- or CCDC-induced HCO3- secretion, the effects inhibited by a GLP-2 receptor antagonist. Coperfusion of the TGR5 agonist enhanced L-Glu/IMP-induced HCO3- secretion with the enhanced GLP-2 release, suggesting that TGR5 activation amplifies nutrient sensing signals. DPPIV inhibition potentiated luminal L-Glu/IMP-induced and TGR5 agonist-induced HCO3- secretion via a GLP-2 pathway, suggesting that the modulation of the local concentration of the endogenous secretagogue GLP-2 by luminal compounds and DPPIV inhibition helps regulate protective duodenal HCO3- secretion. PMID:22821947

  15. Activation of the Constitutive Androstane Receptor Inhibits Gluconeogenesis without Affecting Lipogenesis or Fatty Acid Synthesis in Human Hepatocytes

    PubMed Central

    Lynch, Caitlin; Pan, Yongmei; Li, Linhao; Heyward, Scott; Moeller, Timothy; Swaan, Peter W.; Wang, Hongbing

    2014-01-01

    Objective Accumulating evidence suggests that activation of mouse constitutive androstane receptor (mCAR) alleviates type 2 diabetes and obesity by inhibiting hepatic gluconeogenesis, lipogenesis, and fatty acid synthesis. However, the role of human (h) CAR in energy metabolism is largely unknown. The present study aims to investigate the effects of selective hCAR activators on hepatic energy metabolism in human primary hepatocytes (HPH). Methods Ligand-based structure-activity models were used for virtual screening of the Specs database (www.specs.net) followed by biological validation in cell-based luciferase assays. The effects of two novel hCAR activators (UM104 and UM145) on hepatic energy metabolism were evaluated in HPH. Results Real-time PCR and Western blotting analyses reveal that activation of hCAR by UM104 and UM145 significantly repressed the expression of glucose-6-phosphatase and phosphoenolpyruvate carboxykinase, two pivotal gluconeogenic enzymes, while exerting negligible effects on the expression of genes associated with lipogenesis and fatty acid synthesis. Functional experiments show that UM104 and UM145 markedly inhibit hepatic synthesis of glucose but not triglycerides in HPH. In contrast, activation of mCAR by 1,4-bis[2-(3,5-dichloropyridyloxy)]benzene, a selective mCAR activator, repressed the expression of genes associated with gluconeogenesis, lipogenesis, and fatty acid synthesis in mouse primary hepatocytes, which were consistent with previous observations in mouse model in vivo. Conclusion Our findings uncover an important species difference between hCAR and mCAR in hepatic energy metabolism, where hCAR selectively inhibits gluconeogenesis without suppressing fatty acid synthesis. Implications Such species selectivity should be considered when exploring CAR as a potential therapeutic target for metabolic disorders. PMID:24878338

  16. Inhibition of ornithine decarboxylase induction by retinobenzoic acids in relation to their binding affinities to cellular retinoid-binding proteins.

    PubMed

    Takagi, K; Suganuma, M; Kagechika, H; Shudo, K; Ninomiya, M; Muto, Y; Fujiki, H

    1988-01-01

    Retinobenzoic acids induce differentiation of human promyelocytic leukemia cells (HL-60). Like retinoic acid, 14 retinobenzoic acids inhibited the induction of ornithine decarboxylase (ODC) by teleocidin in mouse skin. The mechanism(s) of inhibition of ODC induction by 7 retinobenzoic acids, Am 80, Am 81, Am 580, Am 590, Am 68, Sa 80, and Ch 55 was compared with those by all-trans-retinoic acid and the arotinoid compound 19. Application of 114 nmol of Am 80, Am 81, Am 580, Am 590, Am 68, Sa 80, or Ch 55, 10 min before 11.4 nmol of teleocidin, resulted in 76.7%, 82.0%, 76.2%, 28.3%, 48.4%, 58.6%, and 85.1% inhibition of ODC induction, respectively. Since all-trans-retinoic acid and compound 19 were also inhibitory, we determined whether retinobenzoic acids bind to cellular retinoic acid-binding protein (CRABP) isolated from bovine adrenal glands. Am 80 and Am 580 inhibited the specific binding of 3H-retinoic acid to CRABP, but also showed less affinity than authentic unlabeled retinoic acid and compound 19. Am 81, Am 590, Am 68, Sa 80, and Ch 55 at up to 10 microM were not effective competitors of the binding of either 3H-retinoic acid or 3H-retinol. These results suggest that the inhibition of ODC induction can be mediated by pathways that do not involve CRABP or the cellular retinol-binding protein.

  17. Acidic extracellular pH neutralizes the autophagy-inhibiting activity of chloroquine

    PubMed Central

    Pellegrini, Paola; Strambi, Angela; Zipoli, Chiara; Hägg-Olofsson, Maria; Buoncervello, Maria; Linder, Stig; De Milito, Angelo

    2014-01-01

    Acidic pH is an important feature of tumor microenvironment and a major determinant of tumor progression. We reported that cancer cells upregulate autophagy as a survival mechanism to acidic stress. Inhibition of autophagy by administration of chloroquine (CQ) in combination anticancer therapies is currently evaluated in clinical trials. We observed in 3 different human cancer cell lines cultured at acidic pH that autophagic flux is not blocked by CQ. This was consistent with a complete resistance to CQ toxicity in cells cultured in acidic conditions. Conversely, the autophagy-inhibiting activity of Lys-01, a novel CQ derivative, was still detectable at low pH. The lack of CQ activity was likely dependent on a dramatically reduced cellular uptake at acidic pH. Using cell lines stably adapted to chronic acidosis we could confirm that CQ lack of activity was merely caused by acidic pH. Moreover, unlike CQ, Lys-01 was able to kill low pH-adapted cell lines, although higher concentrations were required as compared with cells cultured at normal pH conditions. Notably, buffering medium pH in low pH-adapted cell lines reverted CQ resistance. In vivo analysis of tumors treated with CQ showed that accumulation of strong LC3 signals was observed only in normoxic areas but not in hypoxic/acidic regions. Our observations suggest that targeting autophagy in the tumor environment by CQ may be limited to well-perfused regions but not achieved in acidic regions, predicting possible limitations in efficacy of CQ in antitumor therapies. PMID:24492472

  18. Organochlorines inhibit acetaminophen glucuronidation by redirecting UDP-glucuronic acid towards the D-glucuronate pathway

    SciTech Connect

    Chan, Tom S. Wilson, John X.; Selliah, Subajini; Bilodeau, Marc; Zwingmann, Claudia; Poon, Raymond; O'Brien, Peter J.

    2008-11-01

    Industry-derived organochlorines are persistent environmental pollutants that are a continuing health concern. The effects of these compounds on drug metabolism are not well understood. In the current study we present evidence that the inhibition of acetaminophen (APAP) glucuronidation by minute concentrations of organochlorines correlates well with their ability to stimulate the D-glucuronate pathway leading to ascorbate synthesis. A set of 6 arylated organochlorines, including 5 PCB (polychlorinated biphenyl) congeners, were assessed for their effects on APAP glucuronidation in isolated hepatocytes from male Sprague-Dawley rats. The capacity of each organochlorine to inhibit APAP glucuronidation was found to be directly proportional to its capacity to stimulate ascorbate synthesis. PCB153, PCB28 and bis-(4-chlorophenyl sulfone) (BCPS) in increasing order were the most effective organochlorines for inhibiting APAP glucuronidation and stimulating the D-glucuronate pathway. None of the 3 inhibitors of APAP glucuronidation were able to alter the expression of UGT1A6, UGT1A7 and UGT1A8 (the major isoforms responsible for APAP glucuronidation in the rat), however, their efficacy at inhibiting APAP glucuronidation was proportional to their capacity to deplete UDP-glucuronic acid (UDPGA). BCPS-mediated inhibition of APAP glucuronidation in isolated hepatocytes had non-competitive characteristics and was insensitive to the inactivation of cytochrome P450. The effective organochlorines were also able to selectively stimulate the hydrolysis of UDPGA to UDP and glucuronate in isolated microsomes, but could not inhibit APAP glucuronidation in microsomes when UDPGA was in excess. We conclude that organochlorines are able to inhibit APAP glucuronidation in hepatocytes by depleting UDPGA via redirecting UDPGA towards the D-glucuronate pathway. Because the inhibition is non-competitive, low concentrations of these compounds could have long term inhibitory effects on the

  19. Proteomic Signature of Fatty Acid Biosynthesis Inhibition Available for In Vivo Mechanism-of-Action Studies▿

    PubMed Central

    Wenzel, Michaela; Patra, Malay; Albrecht, Dirk; Chen, David Y.-K.; Nicolaou, K. C.; Metzler-Nolte, Nils; Bandow, Julia E.

    2011-01-01

    Fatty acid biosynthesis is a promising novel antibiotic target. Two inhibitors of fatty acid biosynthesis, platencin and platensimycin, were recently discovered and their molecular targets identified. Numerous structure-activity relationship studies for both platencin and platensimycin are currently being undertaken. We established a proteomic signature for fatty acid biosynthesis inhibition in Bacillus subtilis using platencin, platensimycin, cerulenin, and triclosan. The induced proteins, FabHA, FabHB, FabF, FabI, PlsX, and PanB, are enzymes involved in fatty acid biosynthesis and thus linked directly to the target pathway. The proteomic signature can now be used to assess the in vivo mechanisms of action of compounds derived from structure-activity relationship programs, as demonstrated for the platensimycin-inspired chromium bioorganometallic PM47. It will further serve as a reference signature for structurally novel natural and synthetic antimicrobial compounds with unknown mechanisms of action. In summary, we described a proteomic signature in B. subtilis consisting of six upregulated proteins that is diagnostic of fatty acid biosynthesis inhibition and thus can be applied to advance antibacterial drug discovery programs. PMID:21383089

  20. Acid-base titrations for polyacids: Significance of the pK sub a and parameters in the Kern equation

    NASA Technical Reports Server (NTRS)

    Meites, L.

    1978-01-01

    A new method is suggested for calculating the dissociation constants of polyvalent acids, especially polymeric acids. In qualitative form the most significant characteristics of the titration curves are demonstrated and identified which are obtained when titrating the solutions of such acids with a standard base potentiometrically.

  1. Complete inhibition of food-stimulated gastric acid secretion by combined application of pirenzepine and ranitidine.

    PubMed Central

    Londong, W; Londong, V; Ruthe, C; Weizert, P

    1981-01-01

    In a double-blind, placebo controlled and randomised secretory study the effectiveness of pirenzepine, ranitidine, and their combination was compared intraindividually in eight healthy subjects receiving intravenous bolus injections. Pirenzepine (0.15 mg/kg) plus ranitidine (0.6 mg/kg) suppressed peptone-stimulated gastric acid secretion from 69 +/- 11 to 2 +/- 0.4 mmol H+/3 h; the mean percentage inhibition was 97%. Postprandial gastrin was unaffected. There were only minor side-effects in a few experiments (reduction of salivation, brief blurring of vision), but no prolactin stimulation after ranitidine or ranitidine plus pirenzepine. The combined application of ranitidine and pirenzepine inhibited meal-stimulated acid secretion more effectively and produced fewer side-effects than the combination of cimetidine plus pirenzepine studied previously. PMID:6114900

  2. Inhibition of aberrant complement activation by a dimer of acetylsalicylic acid.

    PubMed

    Lee, Moonhee; Wathier, Matthew; Love, Jennifer A; McGeer, Edith; McGeer, Patrick L

    2015-10-01

    We here report synthesis for the first time of the acetyl salicylic acid dimer 5,5'-methylenebis(2-acetoxybenzoic acid) (DAS). DAS inhibits aberrant complement activation by selectively blocking factor D of the alternative complement pathway and C9 of the membrane attack complex. We have previously identified aurin tricarboxylic and its oligomers as promising agents in this regard. DAS is much more potent, inhibiting erythrocyte hemolysis by complement-activated serum with an IC50 in the 100-170 nanomolar range. There are numerous conditions where self-damage from the complement system has been implicated in the pathology, including such chronic degenerative diseases of aging as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and age-related macular degeneration. Consequently, there is a high priority for the discovery and development of agents that can successfully treat such conditions. DAS holds considerable promise for being such an agent.

  3. Inhibition of Listeria monocytogenes in Fresh Cheese Using Chitosan-Grafted Lactic Acid Packaging.

    PubMed

    Sandoval, Laura N; López, Monserrat; Montes-Díaz, Elizabeth; Espadín, Andres; Tecante, Alberto; Gimeno, Miquel; Shirai, Keiko

    2016-04-08

    A chitosan from biologically obtained chitin was successfully grafted with d,l-lactic acid (LA) in aqueous media using p-toluenesulfonic acid as catalyst to obtain a non-toxic, biodegradable packaging material that was characterized using scanning electron microscopy, water vapor permeability, and relative humidity (RH) losses. Additionally, the grafting in chitosan with LA produced films with improved mechanical properties. This material successfully extended the shelf life of fresh cheese and inhibited the growth of Listeria monocytogenes during 14 days at 4 °C and 22% RH, whereby inoculated samples with chitosan-g-LA packaging presented full bacterial inhibition. The results were compared to control samples and commercial low-density polyethylene packaging.

  4. Inhibition of Listeria monocytogenes in Fresh Cheese Using Chitosan-Grafted Lactic Acid Packaging.

    PubMed

    Sandoval, Laura N; López, Monserrat; Montes-Díaz, Elizabeth; Espadín, Andres; Tecante, Alberto; Gimeno, Miquel; Shirai, Keiko

    2016-01-01

    A chitosan from biologically obtained chitin was successfully grafted with d,l-lactic acid (LA) in aqueous media using p-toluenesulfonic acid as catalyst to obtain a non-toxic, biodegradable packaging material that was characterized using scanning electron microscopy, water vapor permeability, and relative humidity (RH) losses. Additionally, the grafting in chitosan with LA produced films with improved mechanical properties. This material successfully extended the shelf life of fresh cheese and inhibited the growth of Listeria monocytogenes during 14 days at 4 °C and 22% RH, whereby inoculated samples with chitosan-g-LA packaging presented full bacterial inhibition. The results were compared to control samples and commercial low-density polyethylene packaging. PMID:27070568

  5. Anti-Cancer Effect of Lambertianic Acid by Inhibiting the AR in LNCaP Cells

    PubMed Central

    Lee, Myoung-Sun; Lee, Seon-Ok; Kim, Sung-Hoon; Lee, Eun-Ok; Lee, Hyo-Jeong

    2016-01-01

    Lambertianic acid (LA) is known to have anti-allergic and antibacterial effects. However, the anticancer activities and mechanism of action of LA have not been investigated. Therefore, the anticancer effects and mechanism of LA are investigated in this study. LA decreased not only AR protein levels, but also cellular and secretory levels of PSA. Furthermore, LA inhibited nuclear translocation of the AR induced by mibolerone. LA suppressed cell proliferation by inducing G1 arrest, downregulating CDK4/6 and cyclin D1 and activating p53 and its downstream molecules, p21 and p27. LA induced apoptosis and the expression of related proteins, including cleaved caspase-9 and -3, c-PARP and BAX, and inhibited BCl-2. The role of AR in LA-induced apoptosis was assessed by using siRNA. Collectively, these findings suggest that LA exerts the anticancer effect by inhibiting AR and is a valuable therapeutic agent in prostate cancer treatment. PMID:27399684

  6. Gallic acid induces mitotic catastrophe and inhibits centrosomal clustering in HeLa cells.

    PubMed

    Tan, Si; Guan, Xin; Grün, Christoph; Zhou, Zhiqin; Schepers, Ute; Nick, Peter

    2015-12-25

    Cancer cells divide rapidly, providing medical targets for anticancer agents. The polyphenolic gallic acid (GA) is known to be toxic for certain cancer cells. However, the cellular mode of action has not been elucidated. Therefore, the current study addressed a potential effect of GA on the mitosis of cancer cells. GA inhibited viability of HeLa cells in a dose-dependent and time-dependent manner. We could show, using fluorescence-activated cell sorting (FACS), that this inhibition was accompanied by elevated frequency of cells arrested at the G2/M transition. This cell-cycle arrest was accompanied by mitotic catastrophe, and formation of cells with multiple nuclei. These aberrations were preceded by impaired centrosomal clustering. We arrive at a model of action, where GA inhibits the progression of the cell cycle at the G2/M phase by impairing centrosomal clustering which will stimulate mitotic catastrophe. Thus, GA has potential as compound against cervical cancer.

  7. Resistance to herbicides inhibiting the biosynthesis of very-long-chain fatty acids.

    PubMed

    Busi, Roberto

    2014-09-01

    Herbicides that act by inhibiting the biosynthesis of very-long-chain fatty acids (VLCFAs) have been used to control grass weeds in major crops throughout the world for the past 60 years. VLCFA-inhibiting herbicides are generally highly selective in crops, induce similar symptoms in susceptible grasses and can be found within the herbicide groups classified by the HRAC as K3 and N. Even after many years of continuous use, only 12 grass weed species have evolved resistance to VLCFA-inhibiting herbicides. Here, the cases of resistance that have evolved in major grass weed species belonging to the Avena, Echinochloa and Lolium genera in three different agricultural systems are reviewed. In particular we explore the possible reasons why VLCFA herbicides have been slow to select resistant weeds, outline the herbicide mode of action and discuss the resistance mechanisms that are most likely to have been selected.

  8. Inhibition of mycotoxin-producing Aspergillus nomius vsc 23 by lactic acid bacteria and Saccharomyces cerevisiae

    PubMed Central

    Muñoz, R; Arena, M.E.; Silva, J.; González, S.N.

    2010-01-01

    The effect of different fermenting microorganisms on growth of a mycotoxin- producing Aspergillus nomius was assayed. Two lactic acid bacteria, Lactobacillus fermentum and Lactobacillus rhamnosus, and Saccharomyces cerevisiae, all of which are widely used in fermentation and preservation of food, were assayed on their fungus inhibitory properties. Assays were carried out by simultaneous inoculation of one of the possible inhibiting microorganisms and the fungus or subsequent inoculation of one of the microorganisms followed by the fungus. All three microorganisms assayed showed growth inhibition of the mycotoxin-producing Aspergillus strain. L. rhamnosus O236, isolated from sheep milk and selected for its technological properties, showed highest fungal inhibition of the microorganisms assayed. The use of antifungal LAB with excellent technological properties rather than chemical preservatives would enable the food industry to produce organic food without addition of chemical substances. PMID:24031582

  9. Inhibition of iron corrosion in 0.5 M sulphuric acid by metal cations

    NASA Astrophysics Data System (ADS)

    Sathiyanarayanan, S.; Jeyaprabha, C.; Muralidharan, S.; Venkatachari, G.

    2006-09-01

    Corrosion inhibitors are widely used in acid solutions during pickling and descaling. Mostly organic compounds containing N, O, and S groups are employed as inhibitors. In this study, the inhibition performance of metal cations such as Zn 2+, Mn 2+ and Ce 4+ ions in the concentration range 1-10 × 10 -3 M has been found out. The corrosion behaviour of iron in 0.5 M H 2SO 4 in the presence of metal cations is studied using polarization and impedance methods. It is found that the addition of these metal cations inhibits the corrosion markedly. The inhibition effect is in the following order Ce 4+ ≫ Mn 2+ > Zn 2+.

  10. Computational models for drug inhibition of the human apical sodium-dependent bile acid transporter.

    PubMed

    Zheng, Xiaowan; Ekins, Sean; Raufman, Jean-Pierre; Polli, James E

    2009-01-01

    The human apical sodium-dependent bile acid transporter (ASBT; SLC10A2) is the primary mechanism for intestinal bile acid reabsorption. In the colon, secondary bile acids increase the risk of cancer. Therefore, drugs that inhibit ASBT have the potential to increase the risk of colon cancer. The objectives of this study were to identify FDA-approved drugs that inhibit ASBT and to derive computational models for ASBT inhibition. Inhibition was evaluated using ASBT-MDCK monolayers and taurocholate as the model substrate. Computational modeling employed a HipHop qualitative approach, a Hypogen quantitative approach, and a modified Laplacian Bayesian modeling method using 2D descriptors. Initially, 30 compounds were screened for ASBT inhibition. A qualitative pharmacophore was developed using the most potent 11 compounds and applied to search a drug database, yielding 58 hits. Additional compounds were tested, and their K(i) values were measured. A 3D-QSAR and a Bayesian model were developed using 38 molecules. The quantitative pharmacophore consisted of one hydrogen bond acceptor, three hydrophobic features, and five excluded volumes. Each model was further validated with two external test sets of 30 and 19 molecules. Validation analysis showed both models exhibited good predictability in determining whether a drug is a potent or nonpotent ASBT inhibitor. The Bayesian model correctly ranked the most active compounds. In summary, using a combined in vitro and computational approach, we found that many FDA-approved drugs from diverse classes, such as the dihydropyridine calcium channel blockers and HMG CoA-reductase inhibitors, are ASBT inhibitors. PMID:19673539

  11. Computational Models for Drug Inhibition of the Human Apical Sodium-dependent Bile Acid Transporter

    PubMed Central

    Zheng, Xiaowan; Ekins, Sean; Raufman, Jean-Pierre; Polli, James E.

    2009-01-01

    The human apical sodium-dependent bile acid transporter (ASBT; SLC10A2) is the primary mechanism for intestinal bile acid re-absorption. In the colon, secondary bile acids increase the risk of cancer. Therefore, drugs that inhibit ASBT have the potential to increase the risk of colon cancer. The objectives of this study were to identify FDA-approved drugs that inhibit ASBT and to derive computational models for ASBT inhibition. Inhibition was evaluated using ASBT-MDCK monolayers and taurocholate as the model substrate. Computational modeling employed a HipHop qualitative approach, a Hypogen quantitative approach, as well as a modified Laplacian Bayesian modeling method using 2D descriptors. Initially, 30 compounds were screened for ASBT inhibition. A qualitative pharmacophore was developed using the most potent 11 compounds and applied to search a drug database, yielding 58 hits. Additional compounds were tested and their Ki values were measured. A 3D-QSAR and a Bayesian model were developed using 38 molecules. The quantitative pharmacophore consisted of one hydrogen bond acceptor, three hydrophobic features, and five excluded volumes. Each model was further validated with two external test sets of 30 and 19 molecules. Validation analysis showed both models exhibited good predictability in determining whether a drug is a potent or non-potent ASBT inhibitor. The Bayesian model correctly ranked the most active compounds. In summary, using a combined in vitro and computational approach, we found that many FDA-approved drugs from diverse classes, such as the dihydropyridine calcium channel blockers and HMG CoA-reductase inhibitors, are ASBT inhibitors. PMID:19673539

  12. Computational models for drug inhibition of the human apical sodium-dependent bile acid transporter.

    PubMed

    Zheng, Xiaowan; Ekins, Sean; Raufman, Jean-Pierre; Polli, James E

    2009-01-01

    The human apical sodium-dependent bile acid transporter (ASBT; SLC10A2) is the primary mechanism for intestinal bile acid reabsorption. In the colon, secondary bile acids increase the risk of cancer. Therefore, drugs that inhibit ASBT have the potential to increase the risk of colon cancer. The objectives of this study were to identify FDA-approved drugs that inhibit ASBT and to derive computational models for ASBT inhibition. Inhibition was evaluated using ASBT-MDCK monolayers and taurocholate as the model substrate. Computational modeling employed a HipHop qualitative approach, a Hypogen quantitative approach, and a modified Laplacian Bayesian modeling method using 2D descriptors. Initially, 30 compounds were screened for ASBT inhibition. A qualitative pharmacophore was developed using the most potent 11 compounds and applied to search a drug database, yielding 58 hits. Additional compounds were tested, and their K(i) values were measured. A 3D-QSAR and a Bayesian model were developed using 38 molecules. The quantitative pharmacophore consisted of one hydrogen bond acceptor, three hydrophobic features, and five excluded volumes. Each model was further validated with two external test sets of 30 and 19 molecules. Validation analysis showed both models exhibited good predictability in determining whether a drug is a potent or nonpotent ASBT inhibitor. The Bayesian model correctly ranked the most active compounds. In summary, using a combined in vitro and computational approach, we found that many FDA-approved drugs from diverse classes, such as the dihydropyridine calcium channel blockers and HMG CoA-reductase inhibitors, are ASBT inhibitors.

  13. 5-Aminolevulinic Acid Thins Pear Fruits by Inhibiting Pollen Tube Growth via Ca(2+)-ATPase-Mediated Ca(2+) Efflux.

    PubMed

    An, Yuyan; Li, Jie; Duan, Chunhui; Liu, Longbo; Sun, Yongping; Cao, Rongxiang; Wang, Liangju

    2016-01-01

    Chemical fruit thinning has become a popular practice in modern fruit orchards for achieving high quality fruits, reducing costs of hand thinning and promoting return bloom. However, most of the suggested chemical thinners are often concerned for their detrimental effects and environmental problems. 5-Aminolevulic acid (ALA) is a natural, nontoxic, biodegradable, and environment-friendly plant growth regulator. One of its outstanding roles is improving plant photosynthesis and fruit quality. Here, results showed that applying 100-200 mg/L ALA at full bloom stage significantly reduced pear fruit set. Both in vivo and in vitro studies showed that ALA significantly inhibited pollen germination and tube growth. ALA decreased not only cytosolic Ca(2+) concentration ([Ca(2+)]cyt) but also "tip-focused" [Ca(2+)]cyt gradient, indicating that ALA inhibited pollen tube growth by down-regulating calcium signaling. ALA drastically enhanced pollen Ca(2+)-ATPase activity, suggesting that ALA-induced decrease of calcium signaling probably resulted from activating calcium pump. The significant negative correlations between Ca(2+)-ATPase activity and pollen germination or pollen tube length further demonstrated the critical role of calcium pump in ALA's negative effect on pollen germination. Taken together, our results suggest that ALA at low concentrations is a potential biochemical thinner, and it inhibits pollen germination and tube growth via Ca(2+) efflux by activating Ca(2+)-ATPase, thereby thinning fruits by preventing fertilization.

  14. 5-Aminolevulinic Acid Thins Pear Fruits by Inhibiting Pollen Tube Growth via Ca2+-ATPase-Mediated Ca2+ Efflux

    PubMed Central

    An, Yuyan; Li, Jie; Duan, Chunhui; Liu, Longbo; Sun, Yongping; Cao, Rongxiang; Wang, Liangju

    2016-01-01

    Chemical fruit thinning has become a popular practice in modern fruit orchards for achieving high quality fruits, reducing costs of hand thinning and promoting return bloom. However, most of the suggested chemical thinners are often concerned for their detrimental effects and environmental problems. 5-Aminolevulic acid (ALA) is a natural, nontoxic, biodegradable, and environment-friendly plant growth regulator. One of its outstanding roles is improving plant photosynthesis and fruit quality. Here, results showed that applying 100–200 mg/L ALA at full bloom stage significantly reduced pear fruit set. Both in vivo and in vitro studies showed that ALA significantly inhibited pollen germination and tube growth. ALA decreased not only cytosolic Ca2+ concentration ([Ca2+]cyt) but also “tip-focused” [Ca2+]cyt gradient, indicating that ALA inhibited pollen tube growth by down-regulating calcium signaling. ALA drastically enhanced pollen Ca2+-ATPase activity, suggesting that ALA-induced decrease of calcium signaling probably resulted from activating calcium pump. The significant negative correlations between Ca2+-ATPase activity and pollen germination or pollen tube length further demonstrated the critical role of calcium pump in ALA's negative effect on pollen germination. Taken together, our results suggest that ALA at low concentrations is a potential biochemical thinner, and it inhibits pollen germination and tube growth via Ca2+ efflux by activating Ca2+-ATPase, thereby thinning fruits by preventing fertilization. PMID:26904082

  15. Theoretical study of inhibition efficiencies of some amino acids on corrosion of carbon steel in acidic media: green corrosion inhibitors.

    PubMed

    Dehdab, Maryam; Shahraki, Mehdi; Habibi-Khorassani, Sayyed Mostafa

    2016-01-01

    Inhibition efficiencies of three amino acids [tryptophan (B), tyrosine (c), and serine (A)] have been studied as green corrosion inhibitors on corrosion of carbon steel using density functional theory (DFT) method in gas and aqueous phases. Quantum chemical parameters such as EH OMO (highest occupied molecular orbital energy), E LUMO (lowest unoccupied molecular orbital energy), hardness (η), polarizability ([Formula: see text]), total negative charges on atoms (TNC), molecular volume (MV) and total energy (TE) have been calculated at the B3LYP level of theory with 6-311++G** basis set. Consistent with experimental data, theoretical results showed that the order of inhibition efficiency is tryptophan (B) > tyrosine (C) > serine (A). In order to determine the possible sites of nucleophilic and electrophilic attacks, local reactivity has been evaluated through Fukui indices.

  16. Significance of acid-mucin-positive nongoblet columnar cells in the distal esophagus and gastroesophageal junction.

    PubMed

    Chen, Y Y; Wang, H H; Antonioli, D A; Spechler, S J; Zeroogian, J M; Goyal, R; Shahsafaei, A; Odze, R D

    1999-12-01

    Acidic mucin-positive nongoblet columnar cells (NGCC) have recently been observed in the surface epithelium of the gastroesophageal junction (GEJ) and distal esophagus in resections from patients with traditional long segment (>3 cm) Barrett's esophagus (BE). However, the significance of finding acidic mucin-positive NGCC in the surface epithelium of biopsy specimens from the distal esophagus/GEJ region in the absence of goblet cells (GC) remains unknown. Therefore, to determine the significance of mucin histochemical changes in the distal esophagus/GEJ region, we analyzed and compared the types, prevalence, and distribution of neutral and acidic mucins in biopsy specimens obtained from 2 groups of patients: those with (32 patients) and those without (107 patients) GC identified in this area. Various mucin histochemical stains (PAS-Ab pH 2.5, HID-Ab pH 2.5, PB/KOH/PAS) were used to identify neutral mucins, acidic mucins (sialomucins and sulphomucins), and o-acetylated sialomucins. The results were compared between the 2 patient groups and correlated with the clinical, endoscopic, and pathologic features. Compared with patients without GC, patients with GC had a significantly higher male/female ratio and a higher proportion of patients with greater than 3 cm of columnar epithelium within the esophagus. Acidic mucin (sialomucin and sulphomucin)-positive NGCC in the surface, foveolar, and glandular epithelium did not show any correlation with any of the clinical, endoscopic, or pathologic features, such as esophagitis, carditis, antritis, Helicobacter pylori infection, or length of columnar epithelium in the distal esophagus. However, acidic mucin-positive NGCC correlated strongly with the presence of GC (P < .001). For example, sialomucin-positive NGCC were present in 28 of 32 (88%) patients with GC compared with 31 of 107 (29%) patients without GC (P < .001). Similarly, sulphomucin-positive NGCC were present in 20 of 32 (62%) patients with GC, compared with 11 of

  17. Inhibition of mammalian carbonic anhydrase isoforms I-XIV with a series of phenolic acid esters.

    PubMed

    Maresca, Alfonso; Akyuz, Gulay; Osman, Sameh M; AlOthman, Zeid; Supuran, Claudiu T

    2015-11-15

    A series of phenolic acid esters incorporating caffeic, ferulic, and p-coumaric acid, and benzyl, m/p-hydroxyphenethyl- as well as p-hydroxy-phenethoxy-phenethyl moieties were investigated for their inhibitory effects against the metalloenzyme carbonic anhydrase (CA, EC 4.2.1.1). Many of the mammalian isozymes of human (h) or murine (m) origin, hCA I-hCA XII, mCA XIII and hCA XIV, were inhibited in the submicromolar range by these derivatives (with KIs of 0.31-1.03 μM against hCA VA, VB, VI, VII, IX and XIV). The off-target, highly abundant isoforms hCA I and II, as well as hCA III, IV and XII were poorly inhibited by many of these esters, although the original phenolic acids were micromolar inhibitors. These phenols, like others investigated earlier, possess a CA inhibition mechanism distinct of the sulfonamides/sulfamates, clinically used drugs for the treatment of a multitude of pathologies, but with severe side effects due to hCA I/II inhibition. Unlike the sulfonamides, which bind to the catalytic zinc ion, phenols are anchored at the Zn(II)-coordinated water molecule, binding more externally within the active site cavity, and making contacts with amino acid residues at the entrance of the active site. As this is the region with the highest variability between the many CA isozymes found in mammals, this class of compounds shows isoform-selective inhibitory profiles, which may be exploited for obtaining pharmacological agents with less side effects compared to other classes of inhibitors. PMID:26498394

  18. A Small Molecule Inhibits Virion Attachment to Heparan Sulfate- or Sialic Acid-Containing Glycans

    PubMed Central

    Colpitts, Che C.

    2014-01-01

    ABSTRACT Primary attachment to cellular glycans is a critical entry step for most human viruses. Some viruses, such as herpes simplex virus type 1 (HSV-1) and hepatitis C virus (HCV), bind to heparan sulfate, whereas others, such as influenza A virus (IAV), bind to sialic acid. Receptor mimetics that interfere with these interactions are active against viruses that bind to either heparan sulfate or to sialic acid. However, no molecule that inhibits the attachment of viruses in both groups has yet been identified. Epigallocatechin gallate (EGCG), a green tea catechin, is active against many unrelated viruses, including several that bind to heparan sulfate or to sialic acid. We sought to identify the basis for the broad-spectrum activity of EGCG. Here, we show that EGCG inhibits the infectivity of a diverse group of enveloped and nonenveloped human viruses. EGCG acts directly on the virions, without affecting the fluidity or integrity of the virion envelopes. Instead, EGCG interacts with virion surface proteins to inhibit the attachment of HSV-1, HCV, IAV, vaccinia virus, adenovirus, reovirus, and vesicular stomatitis virus (VSV) virions. We further show that EGCG competes with heparan sulfate for binding of HSV-1 and HCV virions and with sialic acid for binding of IAV virions. Therefore, EGCG inhibits unrelated viruses by a common mechanism. Most importantly, we have identified EGCG as the first broad-spectrum attachment inhibitor. Our results open the possibility for the development of small molecule broad-spectrum antivirals targeting virion attachment. IMPORTANCE This study shows that it is possible to develop a small molecule antiviral or microbicide active against the two largest groups of human viruses: those that bind to glycosaminoglycans and those that bind to sialoglycans. This group includes the vast majority of human viruses, including herpes simplex viruses, cytomegalovirus, influenza virus, poxvirus, hepatitis C virus, HIV, and many others. PMID

  19. Fetal hydantoin syndrome: inhibition of placental folic acid transport as a potential mechanism for fetal growth retardation in the rat

    SciTech Connect

    Will, M.; Barnard, J.A.; Said, H.M.; Ghishan, F.K.

    1985-04-01

    Maternal hydantoin ingestion during pregnancy results in a well defined clinical entity termed ''fetal hydantoin syndrome''. The clinical characteristics of this syndrome includes growth retardation, and congenital anomalies. Because folic acid is essential for protein synthesis and growth, and since hydantoin interferes with intestinal transport of folic acid, the authors postulated that part of the fetal hydantoin syndrome may be due to inhibition of placental folic acid by maternal hydantoin. Therefore, they studied in vivo placental folate transport in a well-established model for fetal hydantoin syndrome in the rat. Our results indicate that maternal hydantoin ingestion, significantly decreased fetal weight and placental and fetal uptake of folate compared to controls. To determine whether maternal hydantoin ingestion has a generalized or specific effect on placental function, they examined placental and fetal zinc transport in the same model. Our results indicate that zinc transport is not altered by hydantoin ingestion. They conclude that maternal hydantoin ingestion results in fetal growth retardation which may be due in part to inhibition of placental folate transport.

  20. Inhibition of enzymatic browning of chlorogenic acid by sulfur-containing compounds.

    PubMed

    Kuijpers, Tomas F M; Narváez-Cuenca, Carlos-Eduardo; Vincken, Jean-Paul; Verloop, Annewieke J W; van Berkel, Willem J H; Gruppen, Harry

    2012-04-01

    The antibrowning activity of sodium hydrogen sulfite (NaHSO(3)) was compared to that of other sulfur-containing compounds. Inhibition of enzymatic browning was investigated using a model browning system consisting of mushroom tyrosinase and chlorogenic acid (5-CQA). Development of brown color (spectral analysis), oxygen consumption, and reaction product formation (RP-UHPLC-PDA-MS) were monitored in time. It was found that the compounds showing antibrowning activity either prevented browning by forming colorless addition products with o-quinones of 5-CQA (NaHSO(3), cysteine, and glutathione) or inhibiting the enzymatic activity of tyrosinase (NaHSO(3) and dithiothreitol). NaHSO(3) was different from the other sulfur-containing compounds investigated, because it showed a dual inhibitory effect on browning. Initial browning was prevented by trapping the o-quinones formed in colorless addition products (sulfochlorogenic acid), while at the same time, tyrosinase activity was inhibited in a time-dependent way, as shown by pre-incubation experiments of tyrosinase with NaHSO(3). Furthermore, it was demonstrated that sulfochlorogenic and cysteinylchlorogenic acids were not inhibitors of mushroom tyrosinase.

  1. Na+ Inhibits the Epithelial Na+ Channel by Binding to a Site in an Extracellular Acidic Cleft*

    PubMed Central

    Kashlan, Ossama B.; Blobner, Brandon M.; Zuzek, Zachary; Tolino, Michael; Kleyman, Thomas R.

    2015-01-01

    The epithelial Na+ channel (ENaC) has a key role in the regulation of extracellular fluid volume and blood pressure. ENaC belongs to a family of ion channels that sense the external environment. These channels have large extracellular regions that are thought to interact with environmental cues, such as Na+, Cl−, protons, proteases, and shear stress, which modulate gating behavior. We sought to determine the molecular mechanism by which ENaC senses high external Na+ concentrations, resulting in an inhibition of channel activity. Both our structural model of an ENaC α subunit and the resolved structure of an acid-sensing ion channel (ASIC1) have conserved acidic pockets in the periphery of the extracellular region of the channel. We hypothesized that these acidic pockets host inhibitory allosteric Na+ binding sites. Through site-directed mutagenesis targeting the acidic pocket, we modified the inhibitory response to external Na+. Mutations at selected sites altered the cation inhibitory preference to favor Li+ or K+ rather than Na+. Channel activity was reduced in response to restraining movement within this region by cross-linking structures across the acidic pocket. Our results suggest that residues within the acidic pocket form an allosteric effector binding site for Na+. Our study supports the hypothesis that an acidic cleft is a key ligand binding locus for ENaC and perhaps other members of the ENaC/degenerin family. PMID:25389295

  2. Na+ inhibits the epithelial Na+ channel by binding to a site in an extracellular acidic cleft.

    PubMed

    Kashlan, Ossama B; Blobner, Brandon M; Zuzek, Zachary; Tolino, Michael; Kleyman, Thomas R

    2015-01-01

    The epithelial Na(+) channel (ENaC) has a key role in the regulation of extracellular fluid volume and blood pressure. ENaC belongs to a family of ion channels that sense the external environment. These channels have large extracellular regions that are thought to interact with environmental cues, such as Na(+), Cl(-), protons, proteases, and shear stress, which modulate gating behavior. We sought to determine the molecular mechanism by which ENaC senses high external Na(+) concentrations, resulting in an inhibition of channel activity. Both our structural model of an ENaC α subunit and the resolved structure of an acid-sensing ion channel (ASIC1) have conserved acidic pockets in the periphery of the extracellular region of the channel. We hypothesized that these acidic pockets host inhibitory allosteric Na(+) binding sites. Through site-directed mutagenesis targeting the acidic pocket, we modified the inhibitory response to external Na(+). Mutations at selected sites altered the cation inhibitory preference to favor Li(+) or K(+) rather than Na(+). Channel activity was reduced in response to restraining movement within this region by cross-linking structures across the acidic pocket. Our results suggest that residues within the acidic pocket form an allosteric effector binding site for Na(+). Our study supports the hypothesis that an acidic cleft is a key ligand binding locus for ENaC and perhaps other members of the ENaC/degenerin family. PMID:25389295

  3. D-Amino acids inhibit biofilm formation in Staphylococcus epidermidis strains from ocular infections.

    PubMed

    Ramón-Peréz, Miriam L; Diaz-Cedillo, Francisco; Ibarra, J Antonio; Torales-Cardeña, Azael; Rodríguez-Martínez, Sandra; Jan-Roblero, Janet; Cancino-Diaz, Mario E; Cancino-Diaz, Juan C

    2014-10-01

    Biofilm formation on medical and surgical devices is a major virulence determinant for Staphylococcus epidermidis. The bacterium S. epidermidis is able to produce biofilms on biotic and abiotic surfaces and is the cause of ocular infection (OI). Recent studies have shown that d-amino acids inhibit and disrupt biofilm formation in the prototype strains Bacillus subtilis NCBI3610 and Staphylococcus aureus SCO1. The effect of d-amino acids on S. epidermidis biofilm formation has yet to be tested for clinical or commensal isolates. S. epidermidis strains isolated from healthy skin (n = 3), conjunctiva (n = 9) and OI (n = 19) were treated with d-Leu, d-Tyr, d-Pro, d-Phe, d-Met or d-Ala and tested for biofilm formation. The presence of d-amino acids during biofilm formation resulted in a variety of patterns. Some strains were sensitive to all amino acids tested, while others were sensitive to one or more, and one strain was resistant to all of them when added individually; in this way d-Met inhibited most of the strains (26/31), followed by d-Phe (21/31). Additionally, the use of d-Met inhibited biofilm formation on a contact lens. The use of l-isomers caused no defect in biofilm formation in all strains tested. In contrast, when biofilms were already formed d-Met, d-Phe and d-Pro were able to disrupt it. In summary, here we demonstrated the inhibitory effect of d-amino acids on biofilm formation in S. epidermidis. Moreover, we showed, for the first time, that S. epidermidis clinical strains have a different sensitivity to these compounds during biofilm formation.

  4. Plant growth inhibition by cis-cinnamoyl glucosides and cis-cinnamic acid.

    PubMed

    Hiradate, Syuntaro; Morita, Sayaka; Furubayashi, Akihiro; Fujii, Yoshiharu; Harada, Jiro

    2005-03-01

    Spiraea thunbergii Sieb. contains 1-O-cis-cinnamoyl-beta-D-glucopyranose (CG) and 6-O-(4'-hydroxy-2'-methylene-butyroyl)-1-O-cis-cinnamoyl-beta-D-glucopyranose (BCG) as major plant growth inhibiting constituents. In the present study, we determined the inhibitory activity of CG and BCG on root elongation of germinated seedlings of lettuce (Lactuca sativa), pigweed (Amaranthus retroflexus), red clover (Trifolium pratense), timothy (Phleum pratense), and bok choy (Brassica rapa var chinensis) in comparison with that of two well-known growth inhibitors, 2,4-dichlorophenoxyacetic acid (2,4-D) and (+)-2-cis-4-trans-abscisic acid (cis-ABA), as well as two related chemicals of CG and BCG, cis-cinnamic acid (cis-CA) and trans-cinnamic acid (trans-CA). The EC50 values for CG and BCG on lettuce were roughly one-half to one-quarter of the value for cis-ABA. cis-Cinnamic acid, which is a component of CG and BCG, possessed almost the same inhibitory activity of CG and BCG, suggesting that the essential chemical structure responsible for the inhibitory activity of CG and BCG is cis-CA. The cis-stereochemistry of the methylene moiety is apparently needed for high inhibitory activity, as trans-CA had an EC50 value roughly 100 times that of CG, BCG, and cis-CA. Growth inhibition by CG, BCG, and cis-CA was influenced by the nature of the soil in the growing medium: alluvial soil preserved the bioactivity, whereas volcanic ash and calcareous soils inhibited bioactivity. These findings indicate a potential role of cis-CA and its glucosides as allelochemicals for use as plant growth regulators in agricultural fields.

  5. Plant growth inhibition by cis-cinnamoyl glucosides and cis-cinnamic acid.

    PubMed

    Hiradate, Syuntaro; Morita, Sayaka; Furubayashi, Akihiro; Fujii, Yoshiharu; Harada, Jiro

    2005-03-01

    Spiraea thunbergii Sieb. contains 1-O-cis-cinnamoyl-beta-D-glucopyranose (CG) and 6-O-(4'-hydroxy-2'-methylene-butyroyl)-1-O-cis-cinnamoyl-beta-D-glucopyranose (BCG) as major plant growth inhibiting constituents. In the present study, we determined the inhibitory activity of CG and BCG on root elongation of germinated seedlings of lettuce (Lactuca sativa), pigweed (Amaranthus retroflexus), red clover (Trifolium pratense), timothy (Phleum pratense), and bok choy (Brassica rapa var chinensis) in comparison with that of two well-known growth inhibitors, 2,4-dichlorophenoxyacetic acid (2,4-D) and (+)-2-cis-4-trans-abscisic acid (cis-ABA), as well as two related chemicals of CG and BCG, cis-cinnamic acid (cis-CA) and trans-cinnamic acid (trans-CA). The EC50 values for CG and BCG on lettuce were roughly one-half to one-quarter of the value for cis-ABA. cis-Cinnamic acid, which is a component of CG and BCG, possessed almost the same inhibitory activity of CG and BCG, suggesting that the essential chemical structure responsible for the inhibitory activity of CG and BCG is cis-CA. The cis-stereochemistry of the methylene moiety is apparently needed for high inhibitory activity, as trans-CA had an EC50 value roughly 100 times that of CG, BCG, and cis-CA. Growth inhibition by CG, BCG, and cis-CA was influenced by the nature of the soil in the growing medium: alluvial soil preserved the bioactivity, whereas volcanic ash and calcareous soils inhibited bioactivity. These findings indicate a potential role of cis-CA and its glucosides as allelochemicals for use as plant growth regulators in agricultural fields. PMID:15898503

  6. Inhibition of Tanshinone IIA, salvianolic acid A and salvianolic acid B on Areca nut extract-induced oral submucous fibrosis in vitro.

    PubMed

    Dai, Jian-Ping; Zhu, Dan-Xia; Sheng, Jiang-Tao; Chen, Xiao-Xuan; Li, Wei-Zhong; Wang, Ge-Fei; Li, Kang-Sheng; Su, Yun

    2015-01-01

    Salvia miltiorrhiza Bunge has been reported to possess excellent antifibrotic activity. In this study, we have investigated the effect and mechanism of tanshinone IIA (Tan-IIA), salvianolic acid A (Sal-A) and salvianolic acid B (Sal-B), the important active compounds of Salvia miltiorrhiza Bunge, on areca nut extract (ANE)-induced oral submucous fibrosis (OSF) in vitro. Through human procollagen gene promoter luciferase reporter plasmid assay, hydroxyproline assay, gelatin zymography assay, qRT-PCR, ELISA and Western blot assay, the influence of these three compounds on ANE-stimulated cell viability, collagen accumulation, procollagen gene transcription, MMP-2/-9 activity, MMP-1/-13 and TIMP-1/-2 expression, cytokine secretion and the activation of PI3K/AKT, ERK/JNK/p38 MAPK and TGF-β/Smads pathways were detected. The results showed that Tan-IIA, Sal-A and Sal-B could significantly inhibit the ANE-stimulated abnormal viability and collagen accumulation of mice oral mucosal fibroblasts (MOMFs), inhibit the transcription of procollagen gene COL1A1 and COL3A1, increase MMP-2/-9 activity, decrease TIMP-1/-2 expression and inhibit the transcription and release of CTGF, TGF-β1, IL-6 and TNF-α; Tan-IIA, Sal-A and Sal-B also inhibited the ANE-induced activation of AKT and ERK MAPK pathways in MOMFs and the activation of TGF-β/Smads pathway in HaCaT cells. In conclusion, Tan-IIA, Sal-A and Sal-B possess excellent antifibrotic activity in vitro and can possibly be used to promote the rehabilitation of OSF patients. PMID:25884554

  7. Risk Factors for Development of Cholestatic Drug-Induced Liver Injury: Inhibition of Hepatic Basolateral Bile Acid Transporters Multidrug Resistance-Associated Proteins 3 and 4

    PubMed Central

    Köck, Kathleen; Ferslew, Brian C.; Netterberg, Ida; Yang, Kyunghee; Urban, Thomas J.; Swaan, Peter W.; Stewart, Paul W.

    2014-01-01

    Impaired hepatic bile acid export may contribute to development of cholestatic drug-induced liver injury (DILI). The multidrug resistance-associated proteins (MRP) 3 and 4 are postulated to be compensatory hepatic basolateral bile acid efflux transporters when biliary excretion by the bile salt export pump (BSEP) is impaired. BSEP inhibition is a risk factor for cholestatic DILI. This study aimed to characterize the relationship between MRP3, MRP4, and BSEP inhibition and cholestatic potential of drugs. The inhibitory effect of 88 drugs (100 μM) on MRP3- and MRP4-mediated substrate transport was measured in membrane vesicles. Drugs selected for investigation included 50 BSEP non-inhibitors (24 non-cholestatic; 26 cholestatic) and 38 BSEP inhibitors (16 non-cholestatic; 22 cholestatic). MRP4 inhibition was associated with an increased risk of cholestatic potential among BSEP non-inhibitors. In this group, for each 1% increase in MRP4 inhibition, the odds of the drug being cholestatic increased by 3.1%. Using an inhibition cutoff of 21%, which predicted a 50% chance of cholestasis, 62% of cholestatic drugs inhibited MRP4 (P < 0.05); in contrast, only 17% of non-cholestatic drugs were MRP4 inhibitors. Among BSEP inhibitors, MRP4 inhibition did not provide additional predictive value of cholestatic potential; almost all BSEP inhibitors were also MRP4 inhibitors. Inclusion of pharmacokinetic predictor variables (e.g., maximal unbound concentration in plasma) in addition to percent MRP4 inhibition in logistic regression models did not improve cholestasis prediction. Association of cholestasis with percent MRP3 inhibition was not statistically significant, regardless of BSEP-inhibition status. Inhibition of MRP4, in addition to BSEP, may be a risk factor for the development of cholestatic DILI. PMID:24154606

  8. Asiatic Acid Inhibits Lipopolysaccharide-Induced Acute Lung Injury in Mice.

    PubMed

    Li, Zhiling; Xiao, Xianzhong; Yang, Mingshi

    2016-10-01

    Asiatic acid (AA), a major triterpene isolated from Centella asiatica (L.) Urban, is known to exert various pharmacological activities, including anti-inflammatory and antioxidant effects. The aim of this study was to evaluate the anti-inflammatory effects of AA on lipopolysaccharide (LPS)-induced acute lung injury (ALI) and clarify the underlying mechanisms. Lung pathological changes were assessed by H&E staining. The myeloperoxidase (MPO) activity was detected by MPO assay. The levels of inflammatory cytokines were measured by ELISA. TLR4 and NF-kB expression was detected by Western blot analysis. AA obviously inhibited LPS-induced lung histopathological changes, MPO activity, and inflammatory cell numbers in bronchoalveolar lavage fluid (BALF). Treatment of AA also inhibited LPS-induced TNF-α, IL-6, and IL-1β production. Furthermore, Western blot analysis showed that AA inhibited LPS-induced TLR4 expression and NF-kB activation. In conclusion, AA inhibited LPS-induced ALI in mice by inhibiting inflammatory cytokine production, which is mediated via blocking of the TLR4/NF-kB signaling pathway.

  9. Alpha-lipoic acid protects cardiomyocytes against hypoxia/reoxygenation injury by inhibiting autophagy

    SciTech Connect

    Cao, Xueming; Chen, Aihua Yang, Pingzhen; Song, Xudong; Liu, Yingfeng; Li, Zhiliang; Wang, Xianbao; Wang, Lizi; Li, Yunpeng

    2013-11-29

    Highlights: •We observed the cell viability and death subjected to H/R in H9c2 cardiomyocytes. •We observed the degree of autophagy subjected to H/R in H9c2 cardiomyocytes. •LA inhibited the degree of autophagy in parallel to the enhanced cell survival. •LA inhibited the autophagy in parallel to the decreased total cell death. •We concluded that LA protected cardiomyocytes against H/R by inhibiting autophagy. -- Abstract: Hypoxia/reoxygenation (H/R) is an important in vitro model for exploring the molecular mechanisms and functions of autophagy during myocardial ischemia/reperfusion (I/R). Alpha-lipoic acid (LA) plays an important role in the etiology of cardiovascular disease. Autophagy is widely implicated in myocardial I/R injury. We assessed the degree of autophagy by pretreatment with LA exposed to H/R in H9c2 cell based on the expression levels of Beclin-1, LC3II/LC3I, and green fluorescent protein-labeled LC3 fusion proteins. Autophagic vacuoles were confirmed in H9c2 cells exposed to H/R using transmission electron microscopy. Our findings indicated that pretreatment with LA inhibited the degree of autophagy in parallel to the enhanced cell survival and decreased total cell death in H9c2 cells exposed to H/R. We conclude that LA protects cardiomyocytes against H/R injury by inhibiting autophagy.

  10. Valproic Acid Limits Pancreatic Recovery after Pancreatitis by Inhibiting Histone Deacetylases and Preventing Acinar Redifferentiation Programs.

    PubMed

    Eisses, John F; Criscimanna, Angela; Dionise, Zachary R; Orabi, Abrahim I; Javed, Tanveer A; Sarwar, Sheharyar; Jin, Shunqian; Zhou, Lili; Singh, Sucha; Poddar, Minakshi; Davis, Amy W; Tosun, Akif Burak; Ozolek, John A; Lowe, Mark E; Monga, Satdarshan P; Rohde, Gustavo K; Esni, Farzad; Husain, Sohail Z

    2015-12-01

    The mechanisms by which drugs induce pancreatitis are unknown. A definite cause of pancreatitis is due to the antiepileptic drug valproic acid (VPA). On the basis of three crucial observations-that VPA inhibits histone deacetylases (HDACs), HDACs mediate pancreas development, and aspects of pancreas development are recapitulated during recovery of the pancreas after injury-we hypothesized that VPA does not cause injury on its own, but it predisposes patients to pancreatitis by inhibiting HDACs and provoking an imbalance in pancreatic recovery. In an experimental model of pancreatic injury, we found that VPA delayed recovery of the pancreas and reduced acinar cell proliferation. In addition, pancreatic expression of class I HDACs (which are the primary VPA targets) increased in the midphase of pancreatic recovery. VPA administration inhibited pancreatic HDAC activity and led to the persistence of acinar-to-ductal metaplastic complexes, with prolonged Sox9 expression and sustained β-catenin nuclear activation, findings that characterize a delay in regenerative reprogramming. These effects were not observed with valpromide, an analog of VPA that lacks HDAC inhibition. This is the first report, to our knowledge, that VPA shifts the balance toward pancreatic injury and pancreatitis through HDAC inhibition. The work also identifies a new paradigm for therapies that could exploit epigenetic reprogramming to enhance pancreatic recovery and disorders of pancreatic injury.

  11. Nordihydroguaiaretic Acid Inhibits Insulin-Like Growth Factor Signaling, Growth, and Survival in Human Neuroblastoma Cells

    PubMed Central

    Meyer, Gary E.; Chesler, Louis; Liu, Dandan; Gable, Karissa; Maddux, Betty A.; Goldenberg, David D.; Youngren, Jack F.; Goldfine, Ira D.; Weiss, William A.; Matthay, Katherine K.; Rosenthal, Stephen M.

    2010-01-01

    Neuroblastoma is a common pediatric malignancy that metastasizes to the liver, bone, and other organs. Children with metastatic disease have a less than 50% chance of survival with current treatments. Insulin-like growth factors (IGFs) stimulate neuroblastoma growth, survival, and motility, and are expressed by neuroblastoma cells and the tissues they invade. Thus, therapies that disrupt the effects of IGFs on neuroblastoma tumorigenesis may slow disease progression. We show that NVP-AEW541, a specific inhibitor of the IGF-I receptor (IGF-IR), potently inhibits neuroblastoma growth in vitro. Nordihydroguaiaretic acid (NDGA), a phenolic compound isolated from the creosote bush (Larrea divaricata), has anti-tumor properties against a number of malignancies, has been shown to inhibit the phosphorylation and activation of the IGF-IR in breast cancer cells, and is currently in Phase I trials for prostate cancer. In the present study in neuroblastoma, NDGA inhibits IGF-I-mediated activation of the IGF-IR and disrupts activation of ERK and Akt signaling pathways induced by IGF-I. NDGA inhibits growth of neuroblastoma cells and induces apoptosis at higher doses, causing IGF-I-resistant activation of caspase-3 and a large increase in the fraction of sub-G0 cells. In addition, NDGA inhibits the growth of xenografted human neuroblastoma tumors in nude mice. These results indicate that NDGA may be useful in the treatment of neuroblastoma and may function in part via disruption of IGF-IR signaling. PMID:17486636

  12. Valproic Acid Limits Pancreatic Recovery after Pancreatitis by Inhibiting Histone Deacetylases and Preventing Acinar Redifferentiation Programs.

    PubMed

    Eisses, John F; Criscimanna, Angela; Dionise, Zachary R; Orabi, Abrahim I; Javed, Tanveer A; Sarwar, Sheharyar; Jin, Shunqian; Zhou, Lili; Singh, Sucha; Poddar, Minakshi; Davis, Amy W; Tosun, Akif Burak; Ozolek, John A; Lowe, Mark E; Monga, Satdarshan P; Rohde, Gustavo K; Esni, Farzad; Husain, Sohail Z

    2015-12-01

    The mechanisms by which drugs induce pancreatitis are unknown. A definite cause of pancreatitis is due to the antiepileptic drug valproic acid (VPA). On the basis of three crucial observations-that VPA inhibits histone deacetylases (HDACs), HDACs mediate pancreas development, and aspects of pancreas development are recapitulated during recovery of the pancreas after injury-we hypothesized that VPA does not cause injury on its own, but it predisposes patients to pancreatitis by inhibiting HDACs and provoking an imbalance in pancreatic recovery. In an experimental model of pancreatic injury, we found that VPA delayed recovery of the pancreas and reduced acinar cell proliferation. In addition, pancreatic expression of class I HDACs (which are the primary VPA targets) increased in the midphase of pancreatic recovery. VPA administration inhibited pancreatic HDAC activity and led to the persistence of acinar-to-ductal metaplastic complexes, with prolonged Sox9 expression and sustained β-catenin nuclear activation, findings that characterize a delay in regenerative reprogramming. These effects were not observed with valpromide, an analog of VPA that lacks HDAC inhibition. This is the first report, to our knowledge, that VPA shifts the balance toward pancreatic injury and pancreatitis through HDAC inhibition. The work also identifies a new paradigm for therapies that could exploit epigenetic reprogramming to enhance pancreatic recovery and disorders of pancreatic injury. PMID:26476347

  13. Nordihydroguaiaretic acid inhibits insulin-like growth factor signaling, growth, and survival in human neuroblastoma cells.

    PubMed

    Meyer, Gary E; Chesler, Louis; Liu, Dandan; Gable, Karissa; Maddux, Betty A; Goldenberg, David D; Youngren, Jack F; Goldfine, Ira D; Weiss, William A; Matthay, Katherine K; Rosenthal, Stephen M

    2007-12-15

    Neuroblastoma is a common pediatric malignancy that metastasizes to the liver, bone, and other organs. Children with metastatic disease have a less than 50% chance of survival with current treatments. Insulin-like growth factors (IGFs) stimulate neuroblastoma growth, survival, and motility, and are expressed by neuroblastoma cells and the tissues they invade. Thus, therapies that disrupt the effects of IGFs on neuroblastoma tumorigenesis may slow disease progression. We show that NVP-AEW541, a specific inhibitor of the IGF-I receptor (IGF-IR), potently inhibits neuroblastoma growth in vitro. Nordihydroguaiaretic acid (NDGA), a phenolic compound isolated from the creosote bush (Larrea divaricata), has anti-tumor properties against a number of malignancies, has been shown to inhibit the phosphorylation and activation of the IGF-IR in breast cancer cells, and is currently in Phase I trials for prostate cancer. In the present study in neuroblastoma, NDGA inhibits IGF-I-mediated activation of the IGF-IR and disrupts activation of ERK and Akt signaling pathways induced by IGF-I. NDGA inhibits growth of neuroblastoma cells and induces apoptosis at higher doses, causing IGF-I-resistant activation of caspase-3 and a large increase in the fraction of sub-G0 cells. In addition, NDGA inhibits the growth of xenografted human neuroblastoma tumors in nude mice. These results indicate that NDGA may be useful in the treatment of neuroblastoma and may function in part via disruption of IGF-IR signaling.

  14. Low Na intake suppresses expression of CYP2C23 and arachidonic acid-induced inhibition of ENaC.

    PubMed

    Sun, Peng; Lin, Dao-Hong; Wang, Tong; Babilonia, Elisa; Wang, Zhijian; Jin, Yan; Kemp, Rowena; Nasjletti, Alberto; Wang, Wen-Hui

    2006-12-01

    We previously demonstrated that arachidonic acid (AA) inhibits epithelial Na channels (ENaC) through the cytochrome P-450 (CYP) epoxygenase-dependent pathway (34). In the present study, we tested the hypothesis that low Na intake suppresses the expression of CYP2C23, which is mainly responsible for converting AA to epoxyeicosatrienoic acid (EET) in the kidney (11) and attenuates the AA-induced inhibition of ENaC. Immunostaining showed that CYP2C23 is expressed in the Tamm-Horsfall protein (THP)-positive and aquaporin 2 (AQP2)-positive tubules. This suggests that CYP2C23 is expressed in the thick ascending limb (TAL) and collecting duct (CD). Na restriction significantly suppressed the expression of CYP2C23 in the TAL and CD. Western blot also demonstrated that the expression of CYP2C23 in renal cortex and outer medulla diminished in rats on Na-deficient diet (Na-D) but increased in those on high-Na diet (4%). Moreover, the content of 11,12-epoxyeicosatrienoic acid (EET) decreased in the isolated cortical CD from rats on Na-D compared with those on a normal-Na diet (0.5%). Patch-clamp study showed that application of 15 microM AA inhibited the activity of ENaC by 77% in the CCD of rats on a Na-D for 3 days. However, the inhibitory effect of AA on ENaC was significantly attenuated in rats on Na-D for 14 days. Furthermore, inhibition of CYP epoxygenase with MS-PPOH increased the ENaC activity in the CCD of rats on a control Na diet. We also used microperfusion technique to examine the effect of MS-PPOH on Na transport in the distal nephron. Application of MS-PPOH significantly increased Na absorption in the distal nephron of control rats but had no significant effect on Na absorption in rats on Na-D for 14 days. We conclude that low Na intake downregulates the activity and expression of CYP2C23 and attenuates the inhibitory effect of AA on Na transport. PMID:16849695

  15. Inhibition of protein synthesis may explain the bactericidal properties of hypochlorous acid produced by phagocytic cells

    SciTech Connect

    McKenna, S.M.; Davies, K.J.A.

    1986-05-01

    The authors find that hypochlorous acid (HOCl) and hydrogen peroxide (H/sub 2/O/sub 2/) inhibit protein synthesis in E. coli: HOCl is similarly ordered 10x more efficient than H/sub 2/O/sub 2/. This result may underlie the mechanism of bacterial killing by phagocytes, which use H/sub 2/O/sub 2/ and myeloperoxidase (MPO) to oxidize Cl/sup -/ to HOCl. Protein synthesis (/sup 3/H-leu incorporation) was completely inhibited by 50..mu..M HOCl, whereas 50..mu..M H/sub 2/O/sub 2/ only gave similarly ordered 10% inhibition. Complete inhibition by H/sub 2/O/sub 2/ was only observed at concentrations < 0.5 mM. HOCl was also a more potent inhibitor of cell growth (cultured in M9 medium + glucose) than was H/sub 2/O/sub 2/. No growth occurred at 50..mu..M HOCl: in contrast 0.5 mM H/sub 2/O/sub 2/ was required for similar results. During time-course experiments it was found that the inhibition of cell growth by both HOCl and H/sub 2/O/sub 2/ reached a maximum within 30 min (at any concentration used). HOCl reacts avidly with amino groups to form N-chloroamines but H/sub 2/O/sub 2/ is unreactive. Amino acids (ala, lys, met, trp) or taurine (all at 10 mM) prevented the effects of HOCl but did not affect H/sub 2/O/sub 2/ results. There was an excellent correlation between decreased protein synthesis and diminished cell growth. Inhibition of cell growth was not explained by proteolysis (release of acid-soluble counts), or by loss of membrane integrity. They propose that inhibition of protein synthesis may be a fundamental aspect of the bactericidal functions of phagocytes, and that the production of HOCl by MPO represents a quantitative advantage over H/sub 2/O/sub 2/.

  16. Propionic acid and butyric acid inhibit lipolysis and de novo lipogenesis and increase insulin-stimulated glucose uptake in primary rat adipocytes.

    PubMed

    Heimann, Emilia; Nyman, Margareta; Degerman, Eva

    2015-01-01

    Fermentation of dietary fibers by colonic microbiota generates short-chain fatty acids (SCFAs), e.g., propionic acid and butyric acid, which have been described to have "anti-obesity properties" by ameliorating fasting glycaemia, body weight and insulin tolerance in animal models. In the present study, we therefore investigate if propionic acid and butyric acid have effects on lipolysis, de novo lipogenesis and glucose uptake in primary rat adipocytes. We show that both propionic acid and butyric acid inhibit isoproterenol- and adenosine deaminase-stimulated lipolysis as well as isoproterenol-stimulated lipolysis in the presence of a phosphodiesterase (PDE3) inhibitor. In addition, we show that propionic acid and butyric acid inhibit basal and insulin-stimulated de novo lipogenesis, which is associated with increased phosphorylation and thus inhibition of acetyl CoA carboxylase, a rate-limiting enzyme in fatty acid synthesis. Furthermore, we show that propionic acid and butyric acid increase insulin-stimulated glucose uptake. To conclude, our study shows that SCFAs have effects on fat storage and mobilization as well as glucose uptake in rat primary adipocytes. Thus, the SCFAs might contribute to healthier adipocytes and subsequently also to improved energy metabolism with for example less circulating free fatty acids, which is beneficial in the context of obesity and type 2 diabetes. PMID:26167409

  17. Nitric acid photolysis on surfaces in low-NOx environments: Significant atmospheric implications

    NASA Astrophysics Data System (ADS)

    Zhou, Xianliang; Gao, Honglian; He, Yi; Huang, Gu; Bertman, Steven B.; Civerolo, Kevin; Schwab, James

    2003-12-01

    Nitric acid (HNO3) is the dominant end product of NOx (= NO + NO2) oxidation in the troposphere, and its dry deposition is considered to be a major removal pathway for the atmospheric reactive nitrogen. Here we present both field and laboratory results to demonstrate that HNO3 deposited on ground and vegetation surfaces may undergo effective photolysis to form HONO and NOx, 1-2 orders of magnitude faster than in the gas phase and aqueous phase. With this enhanced rate, HNO3 photolysis on surfaces may significantly impact the chemistry of the overlying atmospheric boundary layer in remote low-NOx regions via the emission of HONO as a radical precursor and the recycling of HNO3 deposited on ground surfaces back to NOx.

  18. Clavulanic Acid: a Beta-Lactamase-Inhibiting Beta-Lactam from Streptomyces clavuligerus

    PubMed Central

    Reading, C.; Cole, M.

    1977-01-01

    A novel β-lactamase inhibitor has been isolated from Streptomyces clavuligerus ATCC 27064 and given the name clavulanic acid. Conditions for the cultivation of the organism and detection and isolation of clavulanic acid are described. This compound resembles the nucleus of a penicillin but differs in having no acylamino side chain, having oxygen instead of sulfur, and containing a β-hydroxyethylidine substituent in the oxazolidine ring. Clavulanic acid is a potent inhibitor of many β-lactamases, including those found in Escherichia coli (plasmid mediated), Klebsiella aerogenes, Proteus mirabilis, and Staphylococcus aureus, the inhibition being of a progressive type. The cephalosporinase type of β-lactamase found in Pseudomonas aeruginosa and Enterobacter cloacae P99 and the chromosomally mediated β-lactamase of E. coli are less well inhibited. The minimum inhibitory concentrations of ampicillin and cephaloridine against β-lactamase-producing, penicillin-resistant strains of S. aureus, K. aerogenes, P. mirabilis, and E. coli have been shown to be considerably reduced by the addition of low concentrations of clavulanic acid. Images PMID:879738

  19. Naphthenic acids inhibit root water transport, gas exchange and leaf growth in aspen (Populus tremuloides) seedlings.

    PubMed

    Kamaluddin, M; Zwiazek, Janusz J

    2002-12-01

    Effects of sodium naphthenates (NAs) on root hydraulic conductivity (Lp) and gas exchange processes were examined in aspen (Populus tremuloides Michx.) seedlings grown in solution culture. Exposure of roots to NAs for 3-5 weeks significantly decreased Lp and stomatal conductance. Root-absorbed NAs also decreased leaf chlorophyll concentration, net photosynthesis and leaf growth. Short-term (< or = 2 h) exposure of excised roots to NAs significantly decreased root water flow (Qv) with a concomitant decline in root respiration. We conclude that NAs metabolically inhibited Lp, likely by affecting water channel activity, and that this inhibition could be responsible for the observed reductions in gas exchange and leaf growth.

  20. Alterations to prepulse inhibition magnitude and latency in adult rats following neonatal treatment with domoic acid and social isolation rearing.

    PubMed

    Marriott, Amber L; Tasker, R Andrew; Ryan, Catherine L; Doucette, Tracy A

    2016-02-01

    Deficits in perceptual, informational, and attentional processing are consistently identified as a core feature in schizophrenia and related neuropsychiatric disorders. Neonatal injections of low doses of the AMPA/kainate agonist domoic acid (DOM) have previously been shown to alter various aspects of perceptual and attentional processing in adult rats. The current study investigated the effects of combined neonatal DOM treatment with isolation rearing on prepulse inhibition behaviour and relevant neurochemical measures, to assess the usefulness of these paradigms in modeling neurodevelopmental disorders. Daily subcutaneous injections of DOM (20 μg/kg) or saline were administered to male and female rat pups from postnatal days (PND) 8-14. After weaning, rats were either housed alone or in groups of 4. Both the magnitude and latency of prepulse inhibition were determined in adulthood (approximately 4.5 months of age) and post-mortem brain tissue was assayed using Western blot. Social isolation alone significantly lowered PPI magnitude in male (but not female) rats while DOM treatment appeared to make animals refractory to this effect. Combining social isolation and DOM treatment caused an additive decrease in PPI startle latency. No statistically significant differences were found in the expression of D1, D2, TH, GAD65 or GAD67 protein in either the prefrontal cortex or hippocampus, although some tendencies toward differences were noted. We conclude that both neonatal low-dose DOM and social isolation affect prepulse inhibition in rats but that each paradigm exerts these effects through different neuronal signalling systems.

  1. Aspirin-sensitive asthma: significance of the cyclooxygenase-inhibiting and protein-binding properties of analgesic drugs.

    PubMed

    Williams, W R; Pawlowicz, A; Davies, B H

    1991-01-01

    The in vitro release of endogenous and exogenous PgF2 alpha from plasma and serum proteins by aspirin and other analgesic drugs has been studied by RIA and equilibrium-dialysis techniques, respectively. Before aspirin addition, the mean plasma level of PgF2 alpha measured by RIA was significantly lower in aspirin-sensitive asthma (ASA) patients (11.3 +/- 6.5 pg/ml; n = 8) than in aspirin-tolerant asthma (ATA) patients (25.0 +/- 11.4 pg/ml; n = 21). After aspirin addition (50 micrograms/ml) the mean PgF2 alpha level detected in plasma by RIA was higher in ASA patients (97.6 +/- 5.5 pg/ml) than in ATA patients (66.9 +/- 4.5). The binding of [3H]PgF2 alpha to serum protein was significantly inhibited by NSAIDs but not by paracetamol (0.2-1.0 mM). These results implicate PgF2 alpha and the protein-binding property of analgesic drugs in the pathogenesis of aspirin-sensitive asthma. PMID:1959973

  2. A novel primary bile acid in the Shoebill stork and herons and its phylogenetic significance.

    PubMed

    Hagey, L R; Schteingart, C D; Ton-Nu, H-T; Hofmann, A F

    2002-05-01

    The Shoebill stork, an enigma phylogenetically, was found to contain as its dominant biliary bile acid 16alpha-hydroxychenodeoxycholic acid, a heretofore undescribed bile acid. The bile acid occurred as its taurine N-acyl amidate; structure was established by nuclear magnetic resonance (NMR) and mass spectrometry (MS). A search for this novel bile acid in other Ciconiiformes showed that it constituted >92% of biliary bile acids in five of nine herons in the Ardidae, but was absent in all other families (Ciconiidae, Threskiornithidae, Scopidae, Phoenicopteridae). The presence of this biochemical trait in the Shoebill stork and certain herons suggests that these birds are closely related.

  3. Ferulic acid inhibits proliferation and promotes apoptosis via blockage of PI3K/Akt pathway in osteosarcoma cell.

    PubMed

    Wang, Ting; Gong, Xia; Jiang, Rong; Li, Hongzhong; Du, Weimin; Kuang, Ge

    2016-01-01

    Ferulic acid, a ubiquitous phenolic acid abundant in corn, wheat and flax, has potent anti-tumor effect in various cancer cell lines. However, the anti-tumor effect of ferulic acid on osteosarcoma remains unclear. Therefore, we conduct current study to examine the effect of ferulic acid on osteosarcoma cells and explore the underlying mechanisms. In present study, ferulic acid inhibited proliferation and induced apoptosis in both 143B and MG63 osteosarcoma cells dose-dependently, indicated by MTT assay and Annexin V-FITC apoptosis detection. Additionally, ferulic acid induced G0/G1 phase arrest and down-regulated the expression of cell cycle-related protein, CDK 2, CDK 4, CDK 6, confirmed by flow cytometry assay and western blotting. Moreover, ferulic acid upregulated Bax, downregulated Bcl-2, and subsequently enhanced caspase-3 activity. More importantly, ferulic acid dose-dependently inhibited PI3K/Akt activation. Using adenoviruses expressing active Akt, the anti-proliferation and pro-apoptosis of ferulic acid were reverted. Our results demonstrated that ferulic acid might inhibit proliferation and induce apoptosis via inhibiting PI3K/Akt pathway in osteosarcoma cells. Ferulic acid is a novel therapeutic agent for osteosarcoma. PMID:27158383

  4. Inhibition of ileal bile acid transporter: An emerging therapeutic strategy for chronic idiopathic constipation

    PubMed Central

    Mosińska, Paula; Fichna, Jakub; Storr, Martin

    2015-01-01

    Chronic idiopathic constipation is a common disorder of the gastrointestinal tract that encompasses a wide profile of symptoms. Current treatment options for chronic idiopathic constipation are of limited value; therefore, a novel strategy is necessary with an increased effectiveness and safety. Recently, the inhibition of the ileal bile acid transporter has become a promising target for constipation-associated diseases. Enhanced delivery of bile acids into the colon achieves an accelerated colonic transit, increased stool frequency, and relief of constipation-related symptoms. This article provides insight into the mechanism of action of ileal bile acid transporter inhibitors and discusses their potential clinical use for pharmacotherapy of constipation in chronic idiopathic constipation. PMID:26139989

  5. Inhibition of food-borne bacterial pathogens by bacteriocins from lactic acid bacteria isolated from meat.

    PubMed Central

    Lewus, C B; Kaiser, A; Montville, T J

    1991-01-01

    Ten strains of bacteriocin-producing lactic acid bacteria were isolated from retail cuts of meat. These 10 strains along with 11 other bacteriocin-producing lactic acid bacteria were tested for inhibitory activity against psychotrophic pathogens, including four strains of Listeria monocytogenes, two strains of Aeromonas hydrophila, and two strains of Staphylococcus aureus. Inhibition due to acid, hydrogen peroxide, and lytic bacteriophage were excluded. The proteinaceous nature of the inhibitory substance was confirmed by demonstration of its sensitivity to proteolytic enzymes. Eight of the meat isolates had inhibitory activity against all four L. monocytogenes strains. Bacteriocin activity against L. monocytogenes was found in all of the strains obtained from other sources. Activity against A. hydrophila and S. aureus was also common. Images PMID:1908209

  6. Inhibition of ileal bile acid transporter: An emerging therapeutic strategy for chronic idiopathic constipation.

    PubMed

    Mosińska, Paula; Fichna, Jakub; Storr, Martin

    2015-06-28

    Chronic idiopathic constipation is a common disorder of the gastrointestinal tract that encompasses a wide profile of symptoms. Current treatment options for chronic idiopathic constipation are of limited value; therefore, a novel strategy is necessary with an increased effectiveness and safety. Recently, the inhibition of the ileal bile acid transporter has become a promising target for constipation-associated diseases. Enhanced delivery of bile acids into the colon achieves an accelerated colonic transit, increased stool frequency, and relief of constipation-related symptoms. This article provides insight into the mechanism of action of ileal bile acid transporter inhibitors and discusses their potential clinical use for pharmacotherapy of constipation in chronic idiopathic constipation. PMID:26139989

  7. Structural basis of the inhibition of class C acid phosphatases by adenosine 5;#8242;-phosphorothioate

    SciTech Connect

    Singh, Harkewal; Reilly, Thomas J.; Tanner, John J.

    2012-01-20

    The inhibition of phosphatases by adenosine 5'-phosphorothioate (AMPS) was first reported in the late 1960s; however, the structural basis for the inhibition has remained unknown. Here, it is shown that AMPS is a submicromolar inhibitor of class C acid phosphatases, a group of bacterial outer membrane enzymes belonging to the haloacid dehalogenase structural superfamily. Furthermore, the 1.35-{angstrom} resolution crystal structure of the inhibited recombinant Haemophilus influenzae class C acid phosphatase was determined; this is the first structure of a phosphatase complexed with AMPS. The conformation of AMPS is identical to that of the substrate 5'-AMP, except that steric factors force a rotation of the thiophosphoryl out of the normal phosphoryl-binding pocket. This conformation is catalytically nonproductive, because the P atom is not positioned optimally for nucleophilic attack by Asp64, and the O atom of the scissile O-P bond is too far from the Asp (Asp66) that protonates the leaving group. The structure of 5'-AMP complexed with the Asp64 {yields} Asn mutant enzyme was also determined at 1.35-{angstrom} resolution. This mutation induces the substrate to adopt the same nonproductive binding mode that is observed in the AMPS complex. In this case, electrostatic considerations, rather than steric factors, underlie the movement of the phosphoryl. The structures not only provide an explanation for the inhibition by AMPS, but also highlight the precise steric and electrostatic requirements of phosphoryl recognition by class C acid phosphatases. Moreover, the structure of the Asp64 {yields} Asn mutant illustrates how a seemingly innocuous mutation can cause an unexpected structural change.

  8. Eicosapentaenoic acid inhibits voltage-gated sodium channels and invasiveness in prostate cancer cells

    PubMed Central

    Nakajima, T; Kubota, N; Tsutsumi, T; Oguri, A; Imuta, H; Jo, T; Oonuma, H; Soma, M; Meguro, K; Takano, H; Nagase, T; Nagata, T

    2009-01-01

    Background and purpose: The voltage-gated Na+ channels (Nav) and their corresponding current (INa) are involved in several cellular processes, crucial to metastasis of cancer cells. We investigated the effects of eicosapentaenoic (EPA), an omega-3 polyunsaturated fatty acid, on INa and metastatic functions (cell proliferation, endocytosis and invasion) in human and rat prostate cancer cell lines (PC-3 and Mat-LyLu cells). Experimental approach: The whole-cell voltage clamp technique and conventional/quantitative real-time reverse transcriptase polymerase chain reaction analysis were used. The presence of Nav proteins was shown by immunohistochemical methods. Alterations in the fatty acid composition of phospholipids after treatment with EPA and metastatic functions were also examined. Key results: A transient inward Na+ current (INa), highly sensitive to tetrodotoxin, and NaV proteins were found in these cells. Expression of NaV1.6 and NaV1.7 transcripts (SCN8A and SCN9A) was predominant in PC-3 cells, while NaV1.7 transcript (SCN9A) was the major component in Mat-LyLu cells. Tetrodotoxin or synthetic small interfering RNA targeted for SCN8A and SCN9A inhibited metastatic functions (endocytosis and invasion), but failed to inhibit proliferation in PC-3 cells. Exposure to EPA produced a rapid and concentration-dependent suppression of INa. In cells chronically treated (up to 72h) with EPA, the EPA content of cell lipids increased time-dependently, while arachidonic acid content decreased. Treatment of PC-3 cells with EPA decreased levels of mRNA for SCN9A and SCN8A, cell proliferation, invasion and endocytosis. Conclusion and implications: Treatment with EPA inhibited INa directly and also indirectly, by down-regulation of Nav mRNA expression in prostate cancer cells, thus inhibiting their metastatic potential. PMID:19154441

  9. Inhibitive detection of benzoic acid using a novel phenols biosensor based on polyaniline-polyacrylonitrile composite matrix.

    PubMed

    Shan, Dan; Shi, Qiaofang; Zhu, Daobin; Xue, Huaiguo

    2007-07-31

    A novel sensitive and stable phenols amperometric biosensor, based on polyaniline-polyacrylonitrile composite matrix, was applied for determination of benzoic acid. The electrochemical biosensor functioning was based on the inhibition effect of benzoic acid on the biocatalytic activity of the polyphenol oxidase (PPO) to its substrate (catechol) in 0.1M phosphate buffer solution (pH 6.5). A potential value of -50 mV versus SCE, and a constant catechol concentration of 20 microM were selective to carry out the amperometric inhibition measurement. The kinetic parameters Michaelis-Menten constant (K(M)(app)) and maximum current (I(max)) in the absence and in the presence of benzoic acid were also evaluated and the possible inhibition mechanism was deduced. The inhibiting action of benzoic acid on the polyphenol oxidase electrode was reversible and of the typical competitive type, with an apparent inhibition constant of 38 microM. This proposed biosensor detected levels of benzoic acid as low as 2x10(-7)M in solution. In addition, the effects of temperature, pH value of solution on the inhibition and the interferences were investigated and discussed herein. Inhibition studies revealed that the proposed electrochemical biosensor was applicable for monitoring benzoic acid in real sample such as milk, yoghurt, sprite and cola. PMID:19071830

  10. Inhibition of Hyaluronic Acid Synthesis Suppresses Angiogenesis in Developing Endometriotic Lesions

    PubMed Central

    Olivares, Carla N.; Alaniz, Laura D.; Menger, Michael D.; Barañao, Rosa I.; Laschke, Matthias W.; Meresman, Gabriela F.

    2016-01-01

    Background The development and long-term survival of endometriotic lesions is crucially dependent on an adequate vascularization. Hyaluronic acid (HA) through its receptor CD44 has been described to be involved in the process of angiogenesis. Objective To study the effect of HA synthesis inhibition using non-toxic doses of 4-methylumbelliferone (4-MU) on endometriosis-related angiogenesis. Materials and Methods The cytotoxicity of different in vitro doses of 4-MU on endothelial cells was firstly tested by means of a lactate dehydrogenase assay. The anti-angiogenic action of non-cytotoxic doses of 4-MU was then assessed by a rat aortic ring assay. In addition, endometriotic lesions were induced in dorsal skinfold chambers of female BALB/c mice, which were daily treated with an intraperitoneal injection of 0.9% NaCl (vehicle group; n = 6), 20mg/kg 4-MU (n = 8) or 80mg/kg 4-MU (n = 7) throughout an observation period of 14 days. The effect of 4-MU on their vascularization, survival and growth were studied by intravital fluorescence microscopy, histology and immunohistochemistry. Main Results Non-cytotoxic doses of 4-MU effectively inhibited vascular sprout formation in the rat aortic ring assay. Endometriotic lesions in dorsal skinfold chambers of 4-MU-treated mice dose-dependently exhibited a significantly smaller vascularized area and lower functional microvessel density when compared to vehicle-treated controls. Histological analyses revealed a downregulation of HA expression in 4-MU-treated lesions. This was associated with a reduced density of CD31-positive microvessels within the lesions. In contrast, numbers of PCNA-positive proliferating and cleaved caspase-3-positive apoptotic cells did not differ between 4-MU-treated and control lesions. Conclusions The present study demonstrates for the first time that targeting the synthesis of HA suppresses angiogenesis in developing endometriotic lesions. Further studies have to clarify now whether in the future this

  11. Retinoic acid inhibits angiogenesis and tumor growth of thyroid cancer cells.

    PubMed

    Hoffmann, Sebastian; Rockenstein, Andreas; Ramaswamy, Anette; Celik, Ilhan; Wunderlich, Anette; Lingelbach, Susanne; Hofbauer, Lorenz C; Zielke, Andreas

    2007-01-29

    The anti-proliferative effect of retinoic acid (RA) has been documented for various tumors. Some 40% of patients with advanced and poorly differentiated thyroid cancer have been shown to respond to RA with increased uptake of radioiodine. It has been suggested that these effects may be caused by redifferentiation. Presently, little is known about the effects of RA on tumor angiogenesis, a prerequisite for growth and metastatic spread. The aim of the current study was to determine, whether tumor-induced angiogenesis of thyroid cancer is affected by RA. In vitro, the effect of 0.1/10 microM 13-cis RA on tumor cell number (MTT assay) and secretion of VEGF (ELISA) was analyzed in three thyroid cancer cell lines (FTC 236, C634 and XTC), as well as in endothelial cells (HUVEC) over several passages. In vivo, tumor growth, VEGF-expression and microvessel density (VSD) of RA treated thyroid cancer cells after xenotransplantation to nude mice was evaluated by morphometric analysis. In vitro, thyroid cancer cell lines responded to RA with reduced proliferation, ranging from 26 to 34% after 2 weeks of treatment and with up to 80% reduced secretion of VEGF. In vivo, tumor volumes of animals receiving RA were reduced by 33% (FTC 236), 27% (C643) and 6% (XTC), respectively. VSD of experimental tumors was diminished in the FTC 236 (25%) and the C643 cell line (15%), and almost unchanged in XTC tumors (7%). In vivo, VEGF-expression and apoptosis were not significantly affected by RA. In vitro, proliferation of HUVEC was inhibited by conditioned medium of C643 cells pretreated with RA (0.1/10 microM), as well as by administration of RA (0.1/10 microM). This study confirms thyroid tumor cell growth to be inhibited by RA. It demonstrates a decrease of in vitro VEGF accumulation and reduction of VSD in experimental undifferentiated thyroid carcinoma, suggesting that reduced angiogenesis may be an important mechanism responsible for the therapeutic effect of RA in thyroid cancer

  12. A Novel Tetraenoic Fatty Acid Isolated from Amaranthus spinosus Inhibits Proliferation and Induces Apoptosis of Human Liver Cancer Cells.

    PubMed

    Mondal, Arijit; Guria, Tanmoy; Maity, Tapan Kumar; Bishayee, Anupam

    2016-01-01

    Amaranthus spinosus Linn. (Family: Amaranthaceae) has been shown to be useful in preventing and mitigating adverse pathophysiological conditions and complex diseases. However, only limited information is available on the anticancer potential of this plant. In this study, we examined the antiproliferative and pro-apoptotic effects of a novel fatty acid isolated from A. spinosus-(14E,18E,22E,26E)-methyl nonacosa-14,18,22,26 tetraenoate-against HepG2 human liver cancer cells. We used 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay to determine cell viability, flow cytometry assay for cell cycle analysis, and Western blot analysis to measure protein expression of Cdc2), cyclin B1, Bcl-2-associated X protein (Bax), and B-cell lymphoma 2 (Bcl-2). The MTT assay showed that the fatty acid markedly inhibited the proliferation of HepG2 cells in a dosage-dependent fashion, with a half maximal inhibitory concentration (IC50) value of 25.52 µmol/L. This antiproliferative result was superior to that of another known fatty acid, linoleic acid (IC50 38.65 µmol/L), but comparable to that of standard anticancer drug doxorubicin (IC50 24.68 µmol/L). The novel fatty acid also induced apoptosis mediated by downregulation of cyclin B1, upregulation of Bax, and downregulation of Bcl-2, resulting in the G₂/M transition arrest. Our results provide the first experimental evidence that a novel fatty acid isolated from A. spinosus exhibits significant antiproliferative activity mediated through the induction of apoptosis in HepG2 cells. These encouraging results may facilitate the development of A. spinosus fatty acid for the prevention and intervention of hepatocellular carcinoma. PMID:27669220

  13. A Novel Tetraenoic Fatty Acid Isolated from Amaranthus spinosus Inhibits Proliferation and Induces Apoptosis of Human Liver Cancer Cells.

    PubMed

    Mondal, Arijit; Guria, Tanmoy; Maity, Tapan Kumar; Bishayee, Anupam

    2016-09-22

    Amaranthus spinosus Linn. (Family: Amaranthaceae) has been shown to be useful in preventing and mitigating adverse pathophysiological conditions and complex diseases. However, only limited information is available on the anticancer potential of this plant. In this study, we examined the antiproliferative and pro-apoptotic effects of a novel fatty acid isolated from A. spinosus-(14E,18E,22E,26E)-methyl nonacosa-14,18,22,26 tetraenoate-against HepG2 human liver cancer cells. We used 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay to determine cell viability, flow cytometry assay for cell cycle analysis, and Western blot analysis to measure protein expression of Cdc2), cyclin B1, Bcl-2-associated X protein (Bax), and B-cell lymphoma 2 (Bcl-2). The MTT assay showed that the fatty acid markedly inhibited the proliferation of HepG2 cells in a dosage-dependent fashion, with a half maximal inhibitory concentration (IC50) value of 25.52 µmol/L. This antiproliferative result was superior to that of another known fatty acid, linoleic acid (IC50 38.65 µmol/L), but comparable to that of standard anticancer drug doxorubicin (IC50 24.68 µmol/L). The novel fatty acid also induced apoptosis mediated by downregulation of cyclin B1, upregulation of Bax, and downregulation of Bcl-2, resulting in the G₂/M transition arrest. Our results provide the first experimental evidence that a novel fatty acid isolated from A. spinosus exhibits significant antiproliferative activity mediated through the induction of apoptosis in HepG2 cells. These encouraging results may facilitate the development of A. spinosus fatty acid for the prevention and intervention of hepatocellular carcinoma.

  14. A Novel Tetraenoic Fatty Acid Isolated from Amaranthus spinosus Inhibits Proliferation and Induces Apoptosis of Human Liver Cancer Cells

    PubMed Central

    Mondal, Arijit; Guria, Tanmoy; Maity, Tapan Kumar; Bishayee, Anupam

    2016-01-01

    Amaranthus spinosus Linn. (Family: Amaranthaceae) has been shown to be useful in preventing and mitigating adverse pathophysiological conditions and complex diseases. However, only limited information is available on the anticancer potential of this plant. In this study, we examined the antiproliferative and pro-apoptotic effects of a novel fatty acid isolated from A. spinosus—(14E,18E,22E,26E)-methyl nonacosa-14,18,22,26 tetraenoate—against HepG2 human liver cancer cells. We used 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay to determine cell viability, flow cytometry assay for cell cycle analysis, and Western blot analysis to measure protein expression of Cdc2), cyclin B1, Bcl-2-associated X protein (Bax), and B-cell lymphoma 2 (Bcl-2). The MTT assay showed that the fatty acid markedly inhibited the proliferation of HepG2 cells in a dosage-dependent fashion, with a half maximal inhibitory concentration (IC50) value of 25.52 µmol/L. This antiproliferative result was superior to that of another known fatty acid, linoleic acid (IC50 38.65 µmol/L), but comparable to that of standard anticancer drug doxorubicin (IC50 24.68 µmol/L). The novel fatty acid also induced apoptosis mediated by downregulation of cyclin B1, upregulation of Bax, and downregulation of Bcl-2, resulting in the G2/M transition arrest. Our results provide the first experimental evidence that a novel fatty acid isolated from A. spinosus exhibits significant antiproliferative activity mediated through the induction of apoptosis in HepG2 cells. These encouraging results may facilitate the development of A. spinosus fatty acid for the prevention and intervention of hepatocellular carcinoma. PMID:27669220

  15. The inhibitive effect of some quaternary ammonium salts towards corrosion of aluminium in hydrochloric acid solution

    NASA Astrophysics Data System (ADS)

    Mohamed, A.-M. K.; Al-Nadjm, A.; Fouda, A.-A. S.

    1998-10-01

    The inhibitive action of some quaternary ammonium salts towards the corrosion of aluminium in hydrochloric acid was tested by thermometric, mass loss and polarization measurements. Parallelism between the different methods was established. It is suggested that the tested compounds act as cathodic inhibitors. The inhibitors appear to function through adsorption, following the Temkin adsorption isotherm. The values of free energy of adsorption have been calculated and discussed. The inhibitor character of the additives depends upon the concentration as well as the composition of the inhibitor. Within the given homolegous series the contribution of the functional group to adsorption increases with the length of the chain. The aim of this article is to throw some light on the mechanism of inhibition of these bulky molecules on the corrosion of aluminium in hydrochloric acid. L'action inhibitrice de certains sels d'ammonium quaternaires vis-à-vis de la corrosion de l'aluminium dans l'acide chlorhydrique en solution a été testée par des mesures thermiques de perte de matière et de polarisation. Il est suggéré que les composés testés agissent comme des inhibiteurs cathodiques, fonctionnant par adsorption suivant l'isotherme de Temkin. Les énergies libres d'adsorption ont été calculées et discutées. Le caractère inhibiteur des additifs dépend aussi bien de leur concentration que de leur composition. Pour une série d'inhibiteurs homologues, la contribution à l'adsorption du groupe fonctionnel augmente avec la longueur de la chaîne. Le but de cet article est de mieux comprendre le mécanisme d'inhibition de ces grosses molécules sur la corrosion de l'aluminium dans l'acide chlorhydrique.

  16. Controlling enzyme inhibition using an expanded set of genetically encoded amino acids.

    PubMed

    Zheng, Shun; Kwon, Inchan

    2013-09-01

    Enzyme inhibition plays an important role in drug development, metabolic pathway regulation, and biocatalysis with product inhibition. When an inhibitor has high structural similarities to the substrate of an enzyme, controlling inhibitor binding without affecting enzyme substrate binding is often challenging and requires fine-tuning of the active site. We hypothesize that an extended set of genetically encoded amino acids can be used to design an enzyme active site that reduces enzyme inhibitor binding without compromising substrate binding. As a model case, we chose murine dihydrofolate reductase (mDHFR), substrate dihydrofolate, and inhibitor methotrexate. Structural models of mDHFR variants containing non-natural amino acids complexed with each ligand were constructed to identify a key residue for inhibitor binding and non-natural amino acids to replace the key residue. Then, we discovered that replacing the key phenylalanine residue with two phenylalanine analogs (p-bromophenylalanine (pBrF) and L-2-naphthylalanine (2Nal)) enhances binding affinity toward the substrate dihydrofolate over the inhibitor by 4.0 and 5.8-fold, respectively. Such an enhanced selectivity is mainly due to a reduced inhibitor binding affinity by 2.1 and 4.3-fold, respectively. The catalytic efficiency of the mDHFR variant containing pBrF is comparable to that of wild-type mDHFR, whereas the mDHFR variant containing 2Nal exhibits a moderate decrease in the catalytic efficiency. The work described here clearly demonstrates the feasibility of selectively controlling enzyme inhibition using an expanded set of genetically encoded amino acids.

  17. Gambogic acid induces apoptosis and inhibits colorectal tumor growth via mitochondrial pathways

    PubMed Central

    Huang, Guang-Ming; Sun, Yu; Ge, Xin; Wan, Xin; Li, Chun-Bo

    2015-01-01

    AIM: To investigate the effect of gambogic acid (GA) on apoptosis in the HT-29 human colon cancer cell line. METHODS: H-29 cells were used for in vitro experiments in this study. Relative cell viability was assessed using MTT assays. Cell apoptosis was detected by terminal deoxynucleotidyl transferase dUTP nick end labeling and Hoechst 33342 staining, and quantified by flow cytometry. Cellular ultrastructure was observed by transmission electron microscopy. Real-time PCR and Western blot analyses were used to evaluate gene and protein expression levels. For in vivo experiments, BALB/c nude mice received subcutaneous injections of HT-29 cells in the right armpit. When well-established xenografts were palpable with a tumor size of 75 mm3, mice were randomly assigned to a vehicle (negative) control, positive control or GA treatment group (n = 6 each). The animals in the treatment group received one of three dosages of GA (in saline; 5, 10 or 20 mg/kg) via the caudal vein twice weekly, whereas animals in the negative and positive control groups were given equal volumes of 0.9% saline or 10 mg/kg docetaxel, respectively, via the caudal vein once weekly. RESULTS: The cell viability assay showed that GA inhibited proliferation of HT-29 cells in a dose- and time-dependent manner after treatment with GA (0.00, 0.31, 0.62, 1.25, 2.50, 5.00 or 10.00 μmol/L) for 24, 48 or 72 h. After 48 h, the percentage of apoptotic cells in cells treated with 0.00, 1.25, 2.50 and 5.00 μmol/L GA was 1.4% ± 0.3%, 9.8% ± 1.2%, 25.7% ± 3.3% and 49.3% ± 5.8%, respectively. Ultrastructural analysis of HT-29 cells treated for 48 h with 2.5μmol/L GA revealed apoptotic bodies and condensed and fragmented nuclei. Levels of caspase-8, -9 and -3 mRNAs were significantly increased after treatment with GA (1.25, 2.50 or 5.00 μmol/L) for 48 h (P < 0.05 for all). Protein levels of apoptosis-related factors Fas, FasL, FADD, cytochrome c, and Apaf-1 were increased in GA-treated cells, whereas levels

  18. Activation of RAS/ERK alone is insufficient to inhibit RXRα function and deplete retinoic acid in hepatocytes

    SciTech Connect

    Wang, Ai-Guo Song, Ya-Nan; Chen, Jun; Li, Hui-Ling; Dong, Jian-Yi; Cui, Hai-Peng; Yao, Liang; Li, Xue-Feng; Gao, Wen-Ting; Qiu, Ze-Wen; Wang, Fu-Jin; Wang, Jing-Yu

    2014-09-26

    Highlights: • The activation of RAS/ERK is insufficient to inhibit RXRα function and deplete RA. • The retinoid metabolism-related genes are down-regulated by ras oncogene. • The atRA has no effect on preventing hepatic tumorigenesis or curing the developed hepatic nodules. - Abstract: Activation of RAS/ERK signaling pathway, depletion of retinoid, and phosphorylation of retinoid X receptor alpha (RXRα) are frequent events found in liver tumors and thought to play important roles in hepatic tumorigenesis. However, the relationships among them still remained to be elucidated. By exploring the transgenic mouse model of hepatic tumorigenesis induced by liver-specific expression of H-ras12V oncogene, the activation of RAS/ERK, the mRNA expression levels of retinoid metabolism-related genes, the contents of retinoid metabolites, and phosphorylation of RXRα were determined. RAS/ERK signaling pathway was gradually and significantly activated in hepatic tumor adjacent normal liver tissues (P) and hepatic tumor tissues (T) of H-ras12V transgenic mice compared with normal liver tissues (Wt) of wild type mice. On the contrary, the mRNA expression levels of retinoid metabolism-related genes were significantly reduced in P and T compared with Wt. Interestingly, the retinoid metabolites 9-cis-retinoic acid (9cRA) and all-trans-retinoic acid (atRA), the well known ligands for nuclear transcription factor RXR and retinoic acid receptor (RAR), were significantly decreased only in T compared with Wt and P, although the oxidized polar metabolite of atRA, 4-keto-all-trans-retinoic-acid (4-keto-RA) was significantly decreased in both P and T compared with Wt. To our surprise, the functions of RXRα were significantly blocked only in T compared with Wt and P. Namely, the total protein levels of RXRα were significantly reduced and the phosphorylation levels of RXRα were significantly increased only in T compared with Wt and P. Treatment of H-ras12V transgenic mice at 5-week

  19. Methylseleninic acid promotes antitumour effects via nuclear FOXO3a translocation through Akt inhibition

    PubMed Central

    Tarrado-Castellarnau, Míriam; Cortés, Roldán; Zanuy, Miriam; Tarragó-Celada, Josep; Polat, Ibrahim H.; Hill, Richard; Fan, Teresa W.; Link, Wolfgang; Cascante, Marta

    2016-01-01

    Selenium supplement has been shown in clinical trials to reduce the risk of different cancers including lung carcinoma. Previous studies reported that the antiproliferative and pro-apoptotic activities of methylseleninic acid (MSA) in cancer cells could be mediated by inhibition of the PI3K pathway. A better understanding of the downstream cellular targets of MSA will provide information on its mechanism of action and will help to optimise its use in combination therapies with PI3K inhibitors. For this study, the effects of MSA on viability, cell cycle, metabolism, apoptosis, protein and mRNA expression, and Reactive Oxygen Species production were analysed in A549 cells. FOXO3a subcellular localisation was examined in A549 cells and in stably transfected human osteosarcoma U2foxRELOC cells. Our results demonstrate that MSA induces FOXO3a nuclear translocation in A549 cells and in U2OS cells that stably express GFP-FOXO3a. Interestingly, sodium selenite, another selenium compound, did not induce any significant effects on FOXO3a translocation despite inducing apoptosis. Single strand break of DNA, disruption of tumour cell metabolic adaptations, decrease in ROS production, and cell cycle arrest in G1 accompanied by induction of apoptosis are late events occurring after 24 h of MSA treatment in A549 cells. Our findings suggest that FOXO3a is a relevant mediator of the antiproliferative effects of MSA. This new evidence on the mechanistic action of MSA can open new avenues in exploiting its antitumour properties and in the optimal design of novel combination therapies. We present MSA as a promising chemotherapeutic agent with synergistic antiproliferative effects with cisplatin. PMID:26375988

  20. Inhibition of cytochrome P450s enhances (+)-usnic acid cytotoxicity in primary cultured rat hepatocytes.

    PubMed

    Shi, Qiang; Greenhaw, James; Salminen, William F

    2014-08-01

    (+)-Usnic acid (UA) is consumed as a dietary supplement to promote weight loss; however, dietary supplements containing UA have been associated with clinical cases of severe liver injury. UA has been shown to be hepatotoxic in rats and is extensively metabolized by hepatic cytochrome P450s (CYPs); therefore, we examined if UA metabolism results in the formation of cytotoxic metabolites or if metabolism is a detoxification process in primary rat hepatocytes. When CYP activity was suppressed by the non-isoenzyme-selective inhibitor SKF-525A (20 μM), or the CYP1A inhibitor alpha-naphthoflavone (10 μM), or the CYP3A inhibitor ketoconazole (25 μM), the cytotoxicity of UA at 3~6 μM after 3~20 h of exposure was significantly increased as measured by lactate dehydrogenase (LDH) leakage. At 2 h after UA exposure, an earlier time point prior to LDH release, these CYP inhibitors potentiated UA-induced inhibition of cellular respiration as determined by the Clark type oxygen electrode. Cellular adenosine triphosphate (ATP) depletion by UA was also exacerbated by these CYP inhibitors. The CYP2B/2C inhibitor, ticlopidine at 20 μM, showed no effects in parallel experiments. These data demonstrate that UA is bio-transformed to less toxic metabolites in rat primary hepatocytes, probably mainly by CYP1A and 3A, but not 2B/2C. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

  1. Ellagic Acid Derivatives from Rubus ulmifolius Inhibit Staphylococcus aureus Biofilm Formation and Improve Response to Antibiotics

    PubMed Central

    Quave, Cassandra L.; Estévez-Carmona, Miriam; Compadre, Cesar M.; Hobby, Gerren; Hendrickson, Howard; Beenken, Karen E.; Smeltzer, Mark S.

    2012-01-01

    Background Biofilms contribute to the pathogenesis of many forms of Staphylococcus aureus infection. Treatment of these infections is complicated by intrinsic resistance to conventional antibiotics, thus creating an urgent need for strategies that can be used for the prevention and treatment of biofilm-associated infections. Methodology/Principal Findings This study demonstrates that a botanical natural product composition (220D-F2) rich in ellagic acid and its derivatives can limit S. aureus biofilm formation to a degree that can be correlated with increased antibiotic susceptibility. The source of this composition is Rubus ulmifolius Schott. (Rosaceae), a plant used in complementary and alternative medicine in southern Italy for the treatment of skin and soft tissue infections. All S. aureus clonal lineages tested exhibited a reduced capacity to form a biofilm at 220D-F2 concentrations ranging from 50–200 µg/mL, which were well below the concentrations required to limit bacterial growth (530–1040 µg/mL). This limitation was therapeutically relevant in that inclusion of 220D-F2 resulted in enhanced susceptibility to the functionally-distinct antibiotics daptomycin, clindamycin and oxacillin. Testing with kidney and liver cell lines also demonstrated a lack of host cell cytotoxicity at concentrations of 220D-F2 required to achieve these effects. Conclusions/Significance These results demonstrate that extract 220D-F2 from the root of Rubus ulmifolius can be used to inhibit S. aureus biofilm formation to a degree that can be correlated with increased antibiotic susceptibility without toxic effects on normal mammalian cells. Hence, 220D-F2 is a strong candidate for development as a botanical drug for use in the prevention and treatment of S. aureus biofilm-associated infections. PMID:22242149

  2. Selective inhibition of sweetness by the sodium salt of +/-2-(4-methoxyphenoxy)propanoic acid.

    PubMed

    Schiffman, S S; Booth, B J; Sattely-Miller, E A; Graham, B G; Gibes, K M

    1999-08-01

    The purpose of this study was to determine the degree to which the sodium salt of +/-2-(4-methoxyphenoxy)propanoic acid (Na-PMP) reduced sweet intensity ratings of 15 sweeteners in mixtures. Na-PMP has been approved for use in confectionary/frostings, soft candy and snack products in the USA at concentrations up to 150 p.p.m. A trained panel evaluated the effect of Na-PMP on the intensity of the following 15 sweeteners: three sugars (fructose, glucose, sucrose), three terpenoid glycosides (monoammonium glycyrrhizinate, rebaudioside-A, stevioside), two dipeptide derivatives (alitame, aspartame), two N-sulfonylamides (acesulfame-K, sodium saccharin), two polyhydric alcohols (mannitol, sorbitol), 1 dihydrochalcone (neohesperidin dihydrochalcone), one protein (thaumatin) and one sulfamate (sodium cyclamate). Sweeteners were tested at concentrations isosweet with 2.5, 5, 7.5 and 10% sucrose in mixtures with two levels of Na-PMP: 250 and 500 p.p.m. In addition, the 15 sweeteners were tested either immediately or 30 s after a pre-rinse with 500 p.p.m. Na-PMP. In mixtures, Na-PMP at both the 250 and 500 p.p.m. levels significantly blocked sweetness intensity for 12 of the 15 sweeteners. However, when Na-PMP was mixed with three of the 15 sweeteners (monoammonium glycyrrhizinate, neohesperidin dihydrochalcone and thaumatin), there was little reduction in sweetness intensity. Pre-rinsing with Na-PMP both inhibited and enhanced sweetness with the greatest enhancements found for monoammonium glycyrrhizinate, neohesperidin dihydrochalcone and thaumatin, which were not suppressed by Na-PMP in mixtures. The mixture data suggest that Na-PMP is a selective competitive inhibitor of sweet taste. The finding that pre-treatment can produce enhancement may be due to sensitization of sweetener receptors by Na-PMP.

  3. Do pH and flavonoids influence hypochlorous acid-induced catalase inhibition and heme modification?

    PubMed

    Krych-Madej, Justyna; Gebicka, Lidia

    2015-09-01

    Hypochlorous acid (HOCl), highly reactive oxidizing and chlorinating species, is formed in the immune response to invading pathogens by the reaction of hydrogen peroxide with chloride catalyzed by the enzyme myeloperoxidase. Catalase, an important antioxidant enzyme, catalyzing decomposition of hydrogen peroxide to water and molecular oxygen, hampers in vitro HOCl formation, but is also one of the main targets for HOCl. In this work we have investigated HOCl-induced catalase inhibition at different pH, and the influence of flavonoids (catechin, epigallocatechin gallate and quercetin) on this process. It has been shown that HOCl-induced catalase inhibition is independent on pH in the range 6.0-7.4. Preincubation of catalase with epigallocatechin gallate and quercetin before HOCl treatment enhances the degree of catalase inhibition, whereas catechin does not affect this process. Our rapid kinetic measurements of absorption changes around the heme group have revealed that heme modification by HOCl is mainly due to secondary, intramolecular processes. The presence of flavonoids, which reduce active catalase intermediate, Compound I to inactive Compound II have not influenced the kinetics of HOCl-induced heme modification. Possible mechanisms of the reaction of hypochlorous acid with catalase are proposed and the biological consequences are discussed.

  4. Do pH and flavonoids influence hypochlorous acid-induced catalase inhibition and heme modification?

    PubMed

    Krych-Madej, Justyna; Gebicka, Lidia

    2015-09-01

    Hypochlorous acid (HOCl), highly reactive oxidizing and chlorinating species, is formed in the immune response to invading pathogens by the reaction of hydrogen peroxide with chloride catalyzed by the enzyme myeloperoxidase. Catalase, an important antioxidant enzyme, catalyzing decomposition of hydrogen peroxide to water and molecular oxygen, hampers in vitro HOCl formation, but is also one of the main targets for HOCl. In this work we have investigated HOCl-induced catalase inhibition at different pH, and the influence of flavonoids (catechin, epigallocatechin gallate and quercetin) on this process. It has been shown that HOCl-induced catalase inhibition is independent on pH in the range 6.0-7.4. Preincubation of catalase with epigallocatechin gallate and quercetin before HOCl treatment enhances the degree of catalase inhibition, whereas catechin does not affect this process. Our rapid kinetic measurements of absorption changes around the heme group have revealed that heme modification by HOCl is mainly due to secondary, intramolecular processes. The presence of flavonoids, which reduce active catalase intermediate, Compound I to inactive Compound II have not influenced the kinetics of HOCl-induced heme modification. Possible mechanisms of the reaction of hypochlorous acid with catalase are proposed and the biological consequences are discussed. PMID:26116387

  5. Ursodeoxycholic Acid (UDCA) Exerts Anti-Atherogenic Effects by Inhibiting RAGE Signaling in Diabetic Atherosclerosis.

    PubMed

    Chung, Jihwa; An, Shung Hyun; Kang, Sang Won; Kwon, Kihwan

    2016-01-01

    A naturally occurring bile acid, ursodeoxycholic acid (UDCA), is known to alleviate endoplasmic reticulum (ER) stress at the cellular level. However, the detailed action mechanisms of UDCA in atherosclerosis are not fully understood. In this study, we demonstrated whether UDCA exerts anti-atherogenic activity in diabetic atherosclerosis by targeting ER stress and "receptor for advanced glycation endproduct" (RAGE) signaling. UDCA markedly reduced ER stress, RAGE expression, and pro-inflammatory responses [including NF-κB activation and reactive oxygen species (ROS) production] induced in endothelial cells (ECs) by high glucose (HG). In particular, UDCA inhibited HG-induced ROS production by increasing the Nrf2 level. In macrophages, UDCA also blocked HG-induced RAGE and pro-inflammatory cytokine expression and inhibited foam cell formation via upregulation of the ATP-binding cassette (ABC) transporters, ABCA1 and ABCG1. In the diabetic mouse model, UDCA inhibited atheromatous plaque formation by decreasing ER stress, and the levels of RAGE and adhesion molecules. In conclusion, UDCA exerts an anti-atherogenic activity in diabetic atherosclerosis by targeting both ER stress and RAGE signaling. Our work implicates UDCA as a potential therapeutic agent for prevention or treatment of diabetic atherosclerosis. PMID:26807573

  6. Ursodeoxycholic Acid (UDCA) Exerts Anti-Atherogenic Effects by Inhibiting RAGE Signaling in Diabetic Atherosclerosis

    PubMed Central

    Chung, Jihwa; An, Shung Hyun; Kang, Sang Won; Kwon, Kihwan

    2016-01-01

    A naturally occurring bile acid, ursodeoxycholic acid (UDCA), is known to alleviate endoplasmic reticulum (ER) stress at the cellular level. However, the detailed action mechanisms of UDCA in atherosclerosis are not fully understood. In this study, we demonstrated whether UDCA exerts anti-atherogenic activity in diabetic atherosclerosis by targeting ER stress and “receptor for advanced glycation endproduct” (RAGE) signaling. UDCA markedly reduced ER stress, RAGE expression, and pro-inflammatory responses [including NF-κB activation and reactive oxygen species (ROS) production] induced in endothelial cells (ECs) by high glucose (HG). In particular, UDCA inhibited HG-induced ROS production by increasing the Nrf2 level. In macrophages, UDCA also blocked HG-induced RAGE and pro-inflammatory cytokine expression and inhibited foam cell formation via upregulation of the ATP-binding cassette (ABC) transporters, ABCA1 and ABCG1. In the diabetic mouse model, UDCA inhibited atheromatous plaque formation by decreasing ER stress, and the levels of RAGE and adhesion molecules. In conclusion, UDCA exerts an anti-atherogenic activity in diabetic atherosclerosis by targeting both ER stress and RAGE signaling. Our work implicates UDCA as a potential therapeutic agent for prevention or treatment of diabetic atherosclerosis. PMID:26807573

  7. Transient Receptor Potential Vanilloid 4 Inhibits γ-Aminobutyric Acid-Activated Current in Hippocampal Pyramidal Neurons

    PubMed Central

    Hong, Zhiwen; Tian, Yujing; Qi, Mengwen; Li, Yingchun; Du, Yimei; Chen, Lei; Liu, Wentao; Chen, Ling

    2016-01-01

    The balance between excitatory and inhibitory neurotransmitter systems is crucial for the modulation of neuronal excitability in the central nervous system (CNS). The activation of transient receptor potential vanilloid 4 (TRPV4) is reported to enhance the response of hippocampal glutamate receptors, but whether the inhibitory neurotransmitter system can be regulated by TRPV4 remains unknown. γ-aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the CNS. Here, we show that application of transient receptor potential vanilloid 4 (TRPV4) synthetic (GSK1016790A or 4α-PDD) or endogenous agonist (5,6-EET) inhibited GABA-activated current (IGABA) in hippocampal CA1 pyramidal neurons, which was blocked by specific antagonists of TRPV4 and of GABAA receptors. GSK1016790A increased the phosphorylated AMP-activated protein kinase (p-AMPK) and decreased the phosphorylated protein kinase B (p-Akt) protein levels, which was attenuated by removing extracellular calcium or by a calcium/calmodulin-dependent protein kinase kinase-β antagonist. GSK1016790A-induced decrease of p-Akt protein level was sensitive to an AMPK antagonist. GSK1016790A-inhibited IGABA was blocked by an AMPK antagonist or a phosphatidyl inositol 3 kinase (PI3K) agonist. GSK1016790A-induced inhibition of IGABA was also significantly attenuated by a protein kinase C (PKC) antagonist but was unaffected by protein kinase A or calcium/calmodulin-dependent protein kinase II antagonist. We conclude that activation of TRPV4 inhibits GABAA receptor, which may be mediated by activation of AMPK and subsequent down-regulation of PI3K/Akt signaling and activation of PKC signaling. Inhibition of GABAA receptors may account for the neuronal hyperexcitability caused by TRPV4 activation. PMID:27616980

  8. Transient Receptor Potential Vanilloid 4 Inhibits γ-Aminobutyric Acid-Activated Current in Hippocampal Pyramidal Neurons

    PubMed Central

    Hong, Zhiwen; Tian, Yujing; Qi, Mengwen; Li, Yingchun; Du, Yimei; Chen, Lei; Liu, Wentao; Chen, Ling

    2016-01-01

    The balance between excitatory and inhibitory neurotransmitter systems is crucial for the modulation of neuronal excitability in the central nervous system (CNS). The activation of transient receptor potential vanilloid 4 (TRPV4) is reported to enhance the response of hippocampal glutamate receptors, but whether the inhibitory neurotransmitter system can be regulated by TRPV4 remains unknown. γ-aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the CNS. Here, we show that application of transient receptor potential vanilloid 4 (TRPV4) synthetic (GSK1016790A or 4α-PDD) or endogenous agonist (5,6-EET) inhibited GABA-activated current (IGABA) in hippocampal CA1 pyramidal neurons, which was blocked by specific antagonists of TRPV4 and of GABAA receptors. GSK1016790A increased the phosphorylated AMP-activated protein kinase (p-AMPK) and decreased the phosphorylated protein kinase B (p-Akt) protein levels, which was attenuated by removing extracellular calcium or by a calcium/calmodulin-dependent protein kinase kinase-β antagonist. GSK1016790A-induced decrease of p-Akt protein level was sensitive to an AMPK antagonist. GSK1016790A-inhibited IGABA was blocked by an AMPK antagonist or a phosphatidyl inositol 3 kinase (PI3K) agonist. GSK1016790A-induced inhibition of IGABA was also significantly attenuated by a protein kinase C (PKC) antagonist but was unaffected by protein kinase A or calcium/calmodulin-dependent protein kinase II antagonist. We conclude that activation of TRPV4 inhibits GABAA receptor, which may be mediated by activation of AMPK and subsequent down-regulation of PI3K/Akt signaling and activation of PKC signaling. Inhibition of GABAA receptors may account for the neuronal hyperexcitability caused by TRPV4 activation.

  9. Transient Receptor Potential Vanilloid 4 Inhibits γ-Aminobutyric Acid-Activated Current in Hippocampal Pyramidal Neurons.

    PubMed

    Hong, Zhiwen; Tian, Yujing; Qi, Mengwen; Li, Yingchun; Du, Yimei; Chen, Lei; Liu, Wentao; Chen, Ling

    2016-01-01

    The balance between excitatory and inhibitory neurotransmitter systems is crucial for the modulation of neuronal excitability in the central nervous system (CNS). The activation of transient receptor potential vanilloid 4 (TRPV4) is reported to enhance the response of hippocampal glutamate receptors, but whether the inhibitory neurotransmitter system can be regulated by TRPV4 remains unknown. γ-aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the CNS. Here, we show that application of transient receptor potential vanilloid 4 (TRPV4) synthetic (GSK1016790A or 4α-PDD) or endogenous agonist (5,6-EET) inhibited GABA-activated current (I GABA) in hippocampal CA1 pyramidal neurons, which was blocked by specific antagonists of TRPV4 and of GABAA receptors. GSK1016790A increased the phosphorylated AMP-activated protein kinase (p-AMPK) and decreased the phosphorylated protein kinase B (p-Akt) protein levels, which was attenuated by removing extracellular calcium or by a calcium/calmodulin-dependent protein kinase kinase-β antagonist. GSK1016790A-induced decrease of p-Akt protein level was sensitive to an AMPK antagonist. GSK1016790A-inhibited I GABA was blocked by an AMPK antagonist or a phosphatidyl inositol 3 kinase (PI3K) agonist. GSK1016790A-induced inhibition of I GABA was also significantly attenuated by a protein kinase C (PKC) antagonist but was unaffected by protein kinase A or calcium/calmodulin-dependent protein kinase II antagonist. We conclude that activation of TRPV4 inhibits GABAA receptor, which may be mediated by activation of AMPK and subsequent down-regulation of PI3K/Akt signaling and activation of PKC signaling. Inhibition of GABAA receptors may account for the neuronal hyperexcitability caused by TRPV4 activation. PMID:27616980

  10. Acidic mucopolysaccharide from Holothuria leucospilota has antitumor effect by inhibiting angiogenesis and tumor cell invasion in vivo and in vitro.

    PubMed

    Zhang, Weiwei; Lu, Yin; Xu, Bo; Wu, Jiaming; Zhang, Lijuan; Gao, Ming; Zheng, Shizhong; Wang, Aiyun; Zhang, Changbin; Chen, Lei; Lei, Na

    2009-08-01

    Acidic mucopolysaccharide from Holothuria Leucospilota (HS) may affect some steps in metastasis cascade. In vitro, HS inhibited the growth of B16F10 cells and proliferation of VEGF-induced HUVEC dose-dependently compared to the control, VEGF-induced capillary-like tube networks and the numbers of migratory and invasive cells were significantly inhibited by HS in a dose-dependent manner under the cytotoxic doses. Additionally, VEGF-induced vessel sprouting of rat aortic ring was also inhibited by HS. It also has been demonstrated that the invasive ability of B16F10 melanoma cells through the Matrigel-embedded Boyden chamber was suppressed by 0.5 muM HS. The protein level secreted by B16F10 cells of MMP-2,-9 and VEGF were decreased by HS treatment. In vivo, a tumor growth inhibition study was carried out using mice bearing B16F10 cells model of metastasis, no matter experimental or spontaneous, showed that HS at 5.2, 11.6 and 26 mg/kg (weight of mice) could markedly decreased the metastatic tumors in mouse lung in a dose-dependent manner. In CAM assay and Matrigel plug assay in vivo, HS (50 microg/egg and 100 microg/egg) inhibited new blood vessel formation on the growing chick chorioallantoic membrane, and HS (5.2 and 26 mg/kg body weight) reduced the vessel density in Matrigel plugs implanted in mice. Taken together, these results demonstrate that HS has antimetastasic properties possibly via its antiangiogenesis induced by downregulation of VEGF and suppression of invasive ability of cancer cells mediated by downregulation of MMP-2, -9 and their activities.

  11. 2-Octynoic Acid Inhibits Hepatitis C Virus Infection through Activation of AMP-Activated Protein Kinase

    PubMed Central

    Yang, Darong; Xue, Binbin; Wang, Xiaohong; Yu, Xiaoyan; Liu, Nianli; Gao, Yimin; Liu, Chen; Zhu, Haizhen

    2013-01-01

    Many chronic hepatitis C virus (HCV)-infected patients with current therapy do not clear the virus. It is necessary to find novel treatments. The effect of 2-octynoic acid (2-OA) on HCV infection in human hepatocytes was examined. The mechanism of 2-OA antiviral activity was explored. Our data showed that 2-OA abrogated lipid accumulation in HCV replicon cells and virus-infected hepatocytes. It suppressed HCV RNA replication and infectious virus production with no cytotoxicity to the host cells. 2-OA did not affect hepatitis B virus replication in HepG2.2.15 cells derived from HepG2 cells transfected with full genome of HBV. Further study demonstrated that 2-OA activated AMP-activated protein kinase (AMPK) and inhibited acetyl-CoA carboxylase in viral-infected cells. Compound C, a specific inhibitor of AMPK, inhibited AMPK activity and reversed the reduction of intracellular lipid accumulation and the antiviral effect of 2-OA. Knockdown of AMPK expression by RNA interference abolished the activation of AMPK by 2-OA and blocked 2-OA antiviral activity. Interestingly, 2-OA induced interferon-stimulated genes (ISGs) and inhibited microRNA-122 (miR-122) expression in virus-infected hepatocytes. MiR-122 overexpression reversed the antiviral effect of 2-OA. Furthermore, knockdown of AMPK expression reversed both the induction of ISGs and suppression of miR-122 by 2-OA, implying that activated AMPK induces the intracellular innate response through the induction of ISGs and inhibiting miR-122 expression. 2-OA inhibits HCV infection through regulation of innate immune response by activated AMPK. These findings reveal a novel mechanism by which active AMPK inhibits HCV infection. 2-OA and its derivatives hold promise for novel drug development for chronic hepatitis C. PMID:23741428

  12. Faecal free fatty acids in tropical sprue and their possible role in the production of diarrhoea by inhibition of ATPases.

    PubMed Central

    Tiruppathi, C; Balasubramanian, K A; Hill, P G; Mathan, V I

    1983-01-01

    Faecal excretion of fatty acids is increased in patients with tropical sprue because of unabsorbed dietary fatty acids. The excretion of fatty acids correlates well with faecal wet weight. In vitro unsaturated fatty acids inhibited Na K-ATPase and Mg-ATPase isolated from basolateral membranes of enterocytes and colonocytes. These findings are a possible explanation for the observed abnormalities in water and electrolyte absorption by the colon in patients with tropical sprue and steatorrhoea. PMID:6219925

  13. Insights into significance of combined inhibition of MEK and m-TOR signalling output in KRAS mutant non-small-cell lung cancer

    PubMed Central

    Broutin, Sophie; Stewart, Adam; Thavasu, Parames; Paci, Angelo; Bidart, Jean-Michel; Banerji, Udai

    2016-01-01

    Background: We aimed to understand the dependence of MEK and m-TOR inhibition in EGFRWT/ALKnon-rearranged NSCLC cell lines. Methods: In a panel of KRASM and KRASWT NSCLC cell lines, we determined growth inhibition (GI) following maximal reduction in p-ERK and p-S6RP caused by trametinib (MEK inhibitor) and AZD2014 (m-TOR inhibitor), respectively. Results: GI caused by maximal m-TOR inhibition was significantly greater than GI caused by maximal MEK inhibition in the cell line panel (52% vs 18%, P<10−4). There was no significant difference in GI caused by maximal m-TOR compared with maximal m-TOR+MEK inhibition. However, GI caused by the combination was significantly greater in the KRASM cell lines (79% vs 61%, P=0.017). Conclusions: m-TOR inhibition was more critical to GI than MEK inhibition in EGFRWT/ALKnon-rearranged NSCLC cells. The combination of MEK and m-TOR inhibition was most effective in KRASM cells. PMID:27441499

  14. Inhibition of vaccinia mRNA methylation by 2',5'-linked oligo(adenylic acid) triphosphate

    SciTech Connect

    Sharma, O.K.; Goswami, B.B.

    1981-04-01

    Extracts of interferon-treated cells synthesize unique 2',5'-linked oligo(adenylic acid) 5'-phosphates in the presence of ATP and double-stranded RNA. 2',5'-linked oligo(adenylic acid) 5'-triphosphate inhibits protein synthesis at nanomolar concentrations by activating RNase. We have observed that oligo(adenylic acid) 5'-monophosphate and 5'-triphosphate are potent inhibitors of vaccinia mRNA methylation in vitro. Both the methylation of the 5'-terminal guanine at the 7 position and the 2'-O-ribose methylation of the penultimate nucleoside are inhibited. Such inhibition of mRNA methylation is not due to degradation of the mRNA. Inhibition of the requisite modification of the 5' terminus of mRNA by 2',5'-linked oligo(adenylic acids) may be a mechanism of interferon action against both DNA and RNA viruses in which mRNAs derived from them are capped.

  15. Inhibited insulin signaling in mouse hepatocytes is associated with increased phosphatidic acid but not diacylglycerol.

    PubMed

    Zhang, Chongben; Hwarng, Gwen; Cooper, Daniel E; Grevengoed, Trisha J; Eaton, James M; Natarajan, Viswanathan; Harris, Thurl E; Coleman, Rosalind A

    2015-02-01

    Although an elevated triacylglycerol content in non-adipose tissues is often associated with insulin resistance, the mechanistic relationship remains unclear. The data support roles for intermediates in the glycerol-3-phosphate pathway of triacylglycerol synthesis: diacylglycerol (DAG), which may cause insulin resistance in liver by activating PKCϵ, and phosphatidic acid (PA), which inhibits insulin action in hepatocytes by disrupting the assembly of mTOR and rictor. To determine whether increases in DAG and PA impair insulin signaling when produced by pathways other than that of de novo synthesis, we examined primary mouse hepatocytes after enzymatically manipulating the cellular content of DAG or PA. Overexpressing phospholipase D1 or phospholipase D2 inhibited insulin signaling and was accompanied by an elevated cellular content of total PA, without a change in total DAG. Overexpression of diacylglycerol kinase-θ inhibited insulin signaling and was accompanied by an elevated cellular content of total PA and a decreased cellular content of total DAG. Overexpressing glycerol-3-phosphate acyltransferase-1 or -4 inhibited insulin signaling and increased the cellular content of both PA and DAG. Insulin signaling impairment caused by overexpression of phospholipase D1/D2 or diacylglycerol kinase-θ was always accompanied by disassociation of mTOR/rictor and reduction of mTORC2 kinase activity. However, although the protein ratio of membrane to cytosolic PKCϵ increased, PKC activity itself was unaltered. These data suggest that PA, but not DAG, is associated with impaired insulin action in mouse hepatocytes.

  16. Phospholipase D2-dependent inhibition of the nuclear hormone receptor PPARgamma by cyclic phosphatidic acid.

    PubMed

    Tsukahara, Tamotsu; Tsukahara, Ryoko; Fujiwara, Yuko; Yue, Junming; Cheng, Yunhui; Guo, Huazhang; Bolen, Alyssa; Zhang, Chunxiang; Balazs, Louisa; Re, Fabio; Du, Guangwei; Frohman, Michael A; Baker, Daniel L; Parrill, Abby L; Uchiyama, Ayako; Kobayashi, Tetsuyuki; Murakami-Murofushi, Kimiko; Tigyi, Gabor

    2010-08-13

    Cyclic phosphatidic acid (1-acyl-2,3-cyclic-glycerophosphate, CPA), one of nature's simplest phospholipids, is found in cells from slime mold to humans and has a largely unknown function. We find here that CPA is generated in mammalian cells in a stimulus-coupled manner by phospholipase D2 (PLD2) and binds to and inhibits the nuclear hormone receptor PPARgamma with nanomolar affinity and high specificity through stabilizing its interaction with the corepressor SMRT. CPA production inhibits the PPARgamma target-gene transcription that normally drives adipocytic differentiation of 3T3-L1 cells, lipid accumulation in RAW264.7 cells and primary mouse macrophages, and arterial wall remodeling in a rat model in vivo. Inhibition of PLD2 by shRNA, a dominant-negative mutant, or a small molecule inhibitor blocks CPA production and relieves PPARgamma inhibition. We conclude that CPA is a second messenger and a physiological inhibitor of PPARgamma, revealing that PPARgamma is regulated by endogenous agonists as well as by antagonists. PMID:20705243

  17. Salvianolic Acid B Attenuates Experimental Pulmonary Fibrosis through Inhibition of the TGF-β Signaling Pathway

    PubMed Central

    Liu, Qingmei; Chu, Haiyan; Ma, Yanyun; Wu, Ting; Qian, Feng; Ren, Xian; Tu, Wenzhen; Zhou, Xiaodong; Jin, Li; Wu, Wenyu; Wang, Jiucun

    2016-01-01

    Pulmonary fibrosis is a progressive and fatal disorder. In our previous study, we found that the Yiqihuoxue formula (YQHX), a prescription of Traditional Chinese Medicine, had a curative effect on scleroderma, a typical fibrotic disease. The aim of this study was to determine the key ingredient mediating the therapeutic effects of YQHX and to examine its effect on pulmonary fibrosis, including its mechanism. Luciferase reporter assays showed that the most important anti-fibrotic component of the YQHX was Salviae miltiorrhiza (SM). Experiments performed using a bleomycin-instilled mouse model of pulmonary fibrosis showed that Salvianolic acid B (SAB), the major ingredient of SM, had strong anti-inflammatory and anti-fibrotic effects through its inhibition of inflammatory cell infiltration, alveolar structure disruption, and collagen deposition. Furthermore, SAB suppressed TGF-β-induced myofibroblastic differentiation of MRC-5 fibroblasts and TGF-β-mediated epithelial-to-mesenchymal transition of A549 cells by inhibiting both Smad-dependent signaling and the Smad-independent MAPK pathway. Taken together, our results suggest that SM is the key anti-fibrotic component of the YQHX and that SAB, the major ingredient of SM, alleviates experimental pulmonary fibrosis both in vivo and in vitro by inhibiting the TGF-β signaling pathway. Together, these results suggest that SAB potently inhibits pulmonary fibrosis. PMID:27278104

  18. Differential Inhibition by Ferulic Acid of Nitrate and Ammonium Uptake in Zea mays L. 1

    PubMed Central

    Bergmark, Christine L.; Jackson, William A.; Volk, Richard J.; Blum, Udo

    1992-01-01

    The influence of the allelopathic compound ferulic acid (FA) on nitrogen uptake from solutions containing both NO3− and NH4+ was examined in 8-day-old nitrogen-depleted corn (Zea mays L.) seedlings. Concurrent effects on uptake of Cl− and K+ also were assessed. The presence of 250 micromolar FA inhibited the initial (0-1 hours) rate of NO3− uptake and also prevented development of the NO3−-inducible accelerated rate. The pattern of recovery when FA was removed was interpreted as indicating a rapid relief of FA-restricted NO3− uptake activity, followed by a reinitiation of the induction of that activity. No inhibition of NO3− reduction was detected. Ammonium uptake was less sensitive than NO3− uptake to inhibition by FA. An inhibition of Cl− uptake occurred as induction of the NO3− transport system developed in the absence of FA. Alterations of Cl− uptake in the presence of FA were, therefore, a result of a beneficial effect, because NO3− uptake was restricted, and a direct inhibitory effect. The presence of FA increased the initial net K+ loss from the roots during exposure to the low K, ammonium nitrate uptake solution and delayed the recovery to positive net uptake, but it did not alter the general pattern of the response. The implications of the observations are discussed for growth of plants under natural conditions and cultural practices that foster periodic accumulation of allelopathic substances. PMID:16668689

  19. Gastroprotective Effect of Ginger Rhizome (Zingiber officinale) Extract: Role of Gallic Acid and Cinnamic Acid in H+, K+-ATPase/H. pylori Inhibition and Anti-Oxidative Mechanism

    PubMed Central

    Nanjundaiah, Siddaraju M.; Annaiah, Harish Nayaka Mysore; Dharmesh, Shylaja M.

    2011-01-01

    Zinger officinale has been used as a traditional source against gastric disturbances from time immemorial. The ulcer-preventive properties of aqueous extract of ginger rhizome (GRAE) belonging to the family Zingiberaceae is reported in the present study. GRAE at 200 mg kg−1 b.w. protected up to 86% and 77% for the swim stress-/ethanol stress-induced ulcers with an ulcer index (UI) of 50 ± 4.0/46 ± 4.0, respectively, similar to that of lansoprazole (80%) at 30 mg kg−1 b.w. Increased H+, K+-ATPase activity and thiobarbituric acid reactive substances (TBARS) were observed in ulcer-induced rats, while GRAE fed rats showed normalized levels and GRAE also normalized depleted/amplified anti-oxidant enzymes in swim stress and ethanol stress-induced animals. Gastric mucin damage was recovered up to 77% and 74% in swim stress and ethanol stress, respectively after GRAE treatment. GRAE also inhibited the growth of H. pylori with MIC of 300 ± 38 μg and also possessed reducing power, free radical scavenging ability with an IC50 of 6.8 ± 0.4 μg mL−1 gallic acid equivalent (GAE). DNA protection up to 90% at 0.4 μg was also observed. Toxicity studies indicated no lethal effects in rats fed up to 5 g kg−1 b.w. Compositional analysis favored by determination of the efficacy of individual phenolic acids towards their potential ulcer-preventive ability revealed that between cinnamic (50%) and gallic (46%) phenolic acids, cinnamic acid appear to contribute to better H+, K+-ATPase and Helicobacter pylori inhibitory activity, while gallic acid contributes significantly to anti-oxidant activity. PMID:19570992

  20. Omega-3 fatty acids prevent inflammation and metabolic disorder through inhibition of NLRP3 inflammasome activation.

    PubMed

    Yan, Yiqing; Jiang, Wei; Spinetti, Thibaud; Tardivel, Aubry; Castillo, Rosa; Bourquin, Carole; Guarda, Greta; Tian, Zhigang; Tschopp, Jurg; Zhou, Rongbin

    2013-06-27

    Omega-3 fatty acids (ω-3 FAs) have potential anti-inflammatory activity in a variety of inflammatory human diseases, but the mechanisms remain poorly understood. Here we show that stimulation of macrophages with ω-3 FAs, including eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and other family members, abolished NLRP3 inflammasome activation and inhibited subsequent caspase-1 activation and IL-1β secretion. In addition, G protein-coupled receptor 120 (GPR120) and GPR40 and their downstream scaffold protein β-arrestin-2 were shown to be involved in inflammasome inhibition induced by ω-3 FAs. Importantly, ω-3 FAs also prevented NLRP3 inflammasome-dependent inflammation and metabolic disorder in a high-fat-diet-induced type 2 diabetes model. Our results reveal a mechanism through which ω-3 FAs repress inflammation and prevent inflammation-driven diseases and suggest the potential clinical use of ω-3 FAs in gout, autoinflammatory syndromes, or other NLRP3 inflammasome-driven inflammatory diseases.

  1. Omega-3 fatty acids prevent inflammation and metabolic disorder through inhibition of NLRP3 inflammasome activation.

    PubMed

    Yan, Yiqing; Jiang, Wei; Spinetti, Thibaud; Tardivel, Aubry; Castillo, Rosa; Bourquin, Carole; Guarda, Greta; Tian, Zhigang; Tschopp, Jurg; Zhou, Rongbin

    2013-06-27

    Omega-3 fatty acids (ω-3 FAs) have potential anti-inflammatory activity in a variety of inflammatory human diseases, but the mechanisms remain poorly understood. Here we show that stimulation of macrophages with ω-3 FAs, including eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and other family members, abolished NLRP3 inflammasome activation and inhibited subsequent caspase-1 activation and IL-1β secretion. In addition, G protein-coupled receptor 120 (GPR120) and GPR40 and their downstream scaffold protein β-arrestin-2 were shown to be involved in inflammasome inhibition induced by ω-3 FAs. Importantly, ω-3 FAs also prevented NLRP3 inflammasome-dependent inflammation and metabolic disorder in a high-fat-diet-induced type 2 diabetes model. Our results reveal a mechanism through which ω-3 FAs repress inflammation and prevent inflammation-driven diseases and suggest the potential clinical use of ω-3 FAs in gout, autoinflammatory syndromes, or other NLRP3 inflammasome-driven inflammatory diseases. PMID:23809162

  2. Sialic acid glycoproteins inhibit in vitro and in vivo replication of rotaviruses.

    PubMed Central

    Yolken, R H; Willoughby, R; Wee, S B; Miskuff, R; Vonderfecht, S

    1987-01-01

    We investigated the interactions of rotaviruses with glycoproteins and cells that support rotaviral replication. We found that a wide range of naturally occurring glycoproteins, including ovalbumins and ovomucoids from chicken and turkey eggs, and mucin derived from bovine submaxillary glands, inhibit the replication of rotaviruses in MA-104 cells. Our studies further indicated that the glycoproteins bind directly to rotaviruses and that virus-glycoprotein binding is dependent largely upon interactions with sialic acid oligosaccharides. We found that accessible sialic acid oligosaccharides are required for efficient rotavirus infection of MA-104 cells, thus demonstrating that sialic acid oligosaccharides play an important role in the interactions of rotaviruses with both glycoproteins and cells that support rotaviral replication. Bovine submaxillary mucin and chicken ovoinhibitor can also prevent the shedding of rotavirus antigen and the development of rotavirus gastroenteritis in a mouse model of rotavirus infection. Our findings document that a range of glycoproteins inhibit the in vivo and in vitro replication of rotaviruses and suggest that the alteration in the quantity or chemical composition of intestinal glycoproteins is a potential means for the modulation of enteric infections. Images PMID:3025257

  3. Tannic acid inhibited norovirus binding to HBGA receptors, a study of 50 Chinese medicinal herbs.

    PubMed

    Zhang, Xu-Fu; Dai, Ying-Chun; Zhong, Weiming; Tan, Ming; Lv, Zhi-Ping; Zhou, Ying-Chun; Jiang, Xi

    2012-02-15

    Noroviruses (NoVs) are the leading cause of viral acute gastroenteritis affecting people of all ages worldwide. The disease is difficult to control due to its widespread nature and lack of an antiviral or vaccine. NoV infection relies on the interaction of the viruses with histo-blood group antigens (HBGAs) as host receptors. Here we investigated inhibition effects of Chinese medicinal herbs against NoVs binding to HBGAs for potential antivirals against NoVs. Blocking assays was performed using the NoV protrusion (P) protein as NoV surrogate and saliva as HBGAs. Among 50 clinically effective Chinese medicinal herbs against gastroenteritis diseases, two herbs were found highly effective. Chinese Gall blocked NoV P dimer binding to type A saliva at IC(50)=5.35 μg/ml and to B saliva at IC(50)=21.7 μg/ml. Similarly, Pomegranate blocked binding of NoV P dimer to type A saliva at IC(50)=15.59 μg/ml and B saliva at IC(50)=66.67 μg/ml. Literature data on preliminary biochemistry analysis showed that tannic acid is a common composition in the extracts of the two herbs, so we speculate that it might be the effective compound and further studies using commercially available, highly purified tannic acid confirmed the tannic acid as a strong inhibitor in the binding of NoV P protein to both A and B saliva (IC(50)≈0.1 μM). In addition, we tested different forms of hydrolysable tannins with different alkyl esters, including gallic acid, ethyl gallate, lauryl gallate, octyl gallate and propyl gallate. However, none of these tannins-derivatives revealed detectable inhibiting activities. Our data suggested that tannic acid is a promising candidate antiviral against NoVs.

  4. Overexpression of PAD1 and FDC1 results in significant cinnamic acid decarboxylase activity in Saccharomyces cerevisiae.

    PubMed

    Richard, Peter; Viljanen, Kaarina; Penttilä, Merja

    2015-01-01

    The S. cerevisiae PAD1 gene had been suggested to code for a cinnamic acid decarboxylase, converting trans-cinnamic acid to styrene. This was suggested for the reason that the over-expression of PAD1 resulted in increased tolerance toward cinnamic acid, up to 0.6 mM. We show that by over-expression of the PAD1 together with the FDC1 the cinnamic acid decarboxylase activity can be increased significantly. The strain over-expressing PAD1 and FDC1 tolerated cinnamic acid concentrations up to 10 mM. The cooperation of Pad1p and Fdc1p is surprising since the PAD1 has a mitochondrial targeting sequence and the FDC1 codes for a cytosolic protein. The cinnamic acid decarboxylase activity was also seen in the cell free extract. The activity was 0.019 μmol per minute and mg of extracted protein. The overexpression of PAD1 and FDC1 resulted also in increased activity with the hydroxycinnamic acids ferulic acid, p-coumaric acid and caffeinic acid. This activity was not seen when FDC1 was overexpressed alone. An efficient cinnamic acid decarboxylase is valuable for the genetic engineering of yeast strains producing styrene. Styrene can be produced from endogenously produced L-phenylalanine which is converted by a phenylalanine ammonia lyase to cinnamic acid and then by a decarboxylase to styrene.

  5. Protection from hypertension in mice by the Mediterranean diet is mediated by nitro fatty acid inhibition of soluble epoxide hydrolase

    PubMed Central

    Charles, Rebecca L.; Rudyk, Olena; Prysyazhna, Oleksandra; Kamynina, Alisa; Yang, Jun; Morisseau, Christophe; Hammock, Bruce D.; Freeman, Bruce A.; Eaton, Philip

    2014-01-01

    Soluble epoxide hydrolase (sEH) is inhibited by electrophilic lipids by their adduction to Cys521 proximal to its catalytic center. This inhibition prevents hydrolysis of the enzymes’ epoxyeicosatrienoic acid (EET) substrates, so they accumulate inducing vasodilation to lower blood pressure (BP). We generated a Cys521Ser sEH redox-dead knockin (KI) mouse model that was resistant to this mode of inhibition. The electrophilic lipid 10-nitro-oleic acid (NO2-OA) inhibited hydrolase activity and also lowered BP in an angiotensin II-induced hypertension model in wild-type (WT) but not KI mice. Furthermore, EET/dihydroxy-epoxyeicosatrienoic acid isomer ratios were elevated in plasma from WT but not KI mice following NO2-OA treatment, consistent with the redox-dead mutant being resistant to inhibition by lipid electrophiles. sEH was inhibited in WT mice fed linoleic acid and nitrite, key constituents of the Mediterranean diet that elevates electrophilic nitro fatty acid levels, whereas KIs were unaffected. These observations reveal that lipid electrophiles such as NO2-OA mediate antihypertensive signaling actions by inhibiting sEH and suggest a mechanism accounting for protection from hypertension afforded by the Mediterranean diet. PMID:24843165

  6. The amino acid sensor GCN2 controls gut inflammation by inhibiting inflammasome activation

    PubMed Central

    Nakaya, Helder I; Khan, Nooruddin; Ma, Hualing; Gama, Leonardo; Machiah, Deepa K; Lawson, Benton; Hakimpour, Paul; Wang, Yi-chong; Li, Shuzhao; Sharma, Prachi; Kaufman, Randal J; Martinez, Jennifer; Pulendran, Bali

    2016-01-01

    Summary The integrated stress response (ISR) is a homeostatic mechanism by which eukaryotic cells sense and respond to stress-inducing signals, such as amino acid starvation. General controlled nonrepressed (GCN2) kinase is a key orchestrator of the ISR, and modulates cellular metabolism in response to amino acid starvation. Here we demonstrate that GCN2 controls intestinal inflammation by suppressing inflammasome activation. Enhanced activation of ISR was observed in intestinal antigen presenting cells (APCs) and epithelial cells during amino acid starvation, or intestinal inflammation. Genetic deletion of GCN2 in CD11c+ APCs or intestinal epithelial cells resulted in enhanced intestinal inflammation and Th17 responses, due to enhanced inflammasome activation and IL-1β production. This was caused by reduced autophagy in GCN2−/− intestinal APCs and epithelial cells, leading to increased reactive oxygen species (ROS), a potent activator of inflammasomes1. Thus, conditional ablation of Atg5 and Atg7 in intestinal APCs resulted in enhanced ROS and Th17 responses. Furthermore, in vivo blockade of ROS and IL-1β resulted in inhibition of Th17 responses and reduced inflammation in GCN2−/− mice. Importantly, acute amino acid starvation suppressed intestinal inflammation via a mechanism dependent on GCN2. These results reveal a mechanism that couples amino acid sensing with control of intestinal inflammation via GCN2. PMID:26982722

  7. INHIBITION OF FATTY ACID DESATURASES IN Drosophila melanogaster LARVAE BLOCKS FEEDING AND DEVELOPMENTAL PROGRESSION.

    PubMed

    Wang, Yiwen; da Cruz, Tina Correia; Pulfemuller, Alicia; Grégoire, Stéphane; Ferveur, Jean-François; Moussian, Bernard

    2016-05-01

    Fatty acid desaturases are metabolic setscrews. To study their systemic impact on growth in Drosophila melanogaster, we inhibited fatty acid desaturases using the inhibitor CAY10566. As expected, the amount of desaturated lipids is reduced in larvae fed with CAY10566. These animals cease feeding soon after hatching, and their growth is strongly attenuated. A starvation program is not launched, but the expression of distinct metabolic genes is activated, possibly to mobilize storage material. Without attaining the normal size, inhibitor-fed larvae molt to the next stage indicating that the steroid hormone ecdysone triggers molting correctly. Nevertheless, after molting, expression of ecdysone-dependent regulators is not induced. While control larvae molt a second time, these larvae fail to do so and die after few days of straying. These effects are similar to those observed in experiments using larvae deficient for the fatty acid desaturase1 gene. Based on these data, we propose that the ratio of saturated to unsaturated fatty acids adjusts a sensor system that directs feeding behavior. We also hypothesize that loss of fatty acid desaturase activity leads to a block of the genetic program of development progression indirectly by switching on a metabolic compensation program. PMID:27037621

  8. The amino acid sensor GCN2 controls gut inflammation by inhibiting inflammasome activation.

    PubMed

    Ravindran, Rajesh; Loebbermann, Jens; Nakaya, Helder I; Khan, Nooruddin; Ma, Hualing; Gama, Leonardo; Machiah, Deepa K; Lawson, Benton; Hakimpour, Paul; Wang, Yi-chong; Li, Shuzhao; Sharma, Prachi; Kaufman, Randal J; Martinez, Jennifer; Pulendran, Bali

    2016-03-24

    The integrated stress response (ISR) is a homeostatic mechanism by which eukaryotic cells sense and respond to stress-inducing signals, such as amino acid starvation. General controlled non-repressed (GCN2) kinase is a key orchestrator of the ISR, and modulates protein synthesis in response to amino acid starvation. Here we demonstrate in mice that GCN2 controls intestinal inflammation by suppressing inflammasome activation. Enhanced activation of ISR was observed in intestinal antigen presenting cells (APCs) and epithelial cells during amino acid starvation, or intestinal inflammation. Genetic deletion of Gcn2 (also known as Eif2ka4) in CD11c(+) APCs or intestinal epithelial cells resulted in enhanced intestinal inflammation and T helper 17 cell (TH17) responses, owing to enhanced inflammasome activation and interleukin (IL)-1β production. This was caused by reduced autophagy in Gcn2(-/-) intestinal APCs and epithelial cells, leading to increased reactive oxygen species (ROS), a potent activator of inflammasomes. Thus, conditional ablation of Atg5 or Atg7 in intestinal APCs resulted in enhanced ROS and TH17 responses. Furthermore, in vivo blockade of ROS and IL-1β resulted in inhibition of TH17 responses and reduced inflammation in Gcn2(-/-) mice. Importantly, acute amino acid starvation suppressed intestinal inflammation via a mechanism dependent on GCN2. These results reveal a mechanism that couples amino acid sensing with control of intestinal inflammation via GCN2.

  9. Boric acid inhibits germination and colonization of Saprolegnia spores in vitro and in vivo.

    PubMed

    Ali, Shimaa E; Thoen, Even; Evensen, Øystein; Skaar, Ida

    2014-01-01

    Saprolegnia infections cause severe economic losses among freshwater fish and their eggs. The banning of malachite green increased the demand for finding effective alternative treatments to control the disease. In the present study, we investigated the ability of boric acid to control saprolegniosis in salmon eggs and yolk sac fry. Under in vitro conditions, boric acid was able to decrease Saprolegnia spore activity and mycelial growth in all tested concentrations above 0.2 g/L, while complete inhibition of germination and growth was observed at a concentration of 0.8 g/L. In in vivo experiments using Atlantic salmon eyed eggs, saprolegniosis was controlled by boric acid at concentrations ranging from 0.2-1.4 g/L during continuous exposure, and at 1.0-4.0 g/L during intermittent exposure. The same effect was observed on salmon yolk sac fry exposed continuously to 0.5 g/L boric acid during the natural outbreak of saprolegniosis. During the experiments no negative impact with regard to hatchability and viability was observed in either eggs or fry, which indicate safety of use at all tested concentrations. The high hatchability and survival rates recorded following the in vivo testing suggest that boric acid is a candidate for prophylaxis and control of saprolegniosis.

  10. Inhibition kinetics of acid and alkaline phosphatases by atrazine and methomyl pesticides.

    PubMed

    El-Aswad, Ahmed F; Badawy, Mohamed E I

    2015-01-01

    The main objective of this work was to investigate the kinetic characteristics of acid and alkaline phosphatases isolated from different sources and to study the effects of the herbicide atrazine and insecticide methomyl on the activity and kinetic properties of the enzymes. Acid phosphatase (ACP) was isolated from the tomato plant (Solanum lycopersicum L. var. lycopersicum); alkaline phosphatase (ALP) was isolated from two sources, including mature earthworms (Aporrectodea caliginosa) and larvae of the Egyptian cotton leafworm (Spodoptera littoralis). The specific activities of the enzymes were 33.31, 5.56 and 0.72 mmol substrate hydrolyzed per minute per milligram protein for plant ACP, earthworms ALP and cotton leafworm ALP, respectively. The inhibition kinetics indicated that atrazine and methomyl caused competitive-non-competitive inhibition of the enzymes. The relationships between estimates of K(m) and V(max) calculated from the Michaelis-Menten equation have been explored. The extent of the inhibition was different, as estimated by the values of the inhibition constant Ki that were found to be 3.34 × 10(-3), 1.12 × 10(-2) and 1.07 × 10(-2) mM for plant ACP, earthworms ALP and cotton leafworm ALP, respectively, with methomyl. In the case of atrazine, K(i) were found to be 8.99 × 10(-3), 3.55 × 10(-2) and 1.36 × 10(-2) mM for plant ACP, earthworms ALP and cotton leafworm ALP, respectively. PMID:25996812

  11. Molecular hairpin: a possible model for inhibition of tau aggregation by tannic acid.

    PubMed

    Yao, Junliang; Gao, Xing; Sun, Wenliang; Yao, Tianming; Shi, Shuo; Ji, Liangnian

    2013-03-19

    Inhibition of anomalous aggregation of tau protein would be an attractive therapeutic target for Alzheimer's disease (AD). In this study, tannic acid (TA), a polymeric plant polyphenol, and its monomer, gallic acid (GA), were introduced as the references to afford a molecular framework that integrates tau binding properties and inhibitory effects. Using a thioflavin S fluorescence assay and electron microscopy, we demonstrated that TA could competently inhibit the in vitro aggregation of tau peptide R3, corresponding to the third repeat unit of the microtubule-binding domain, with an IC50 of 3.5 μM, while GA's inhibition was comparatively piddling (with an IC50 of 92 μM). In the isothermal titration calorimetry experiment, we found that TA could strongly bind to R3 with a large amount of heat released. Circular dichroism spectra showed TA dose-dependently suppressed the conformational transition of R3 from a random coil structure to a β-sheet structure during the aggregation process. Finally, a structural model was built using molecular docking simulation to elucidate the possible binding sites for TA on the tau peptide surface. Our results suggest that TA recognizably interacts with tau peptide by forming a hairpin binding motif, a key framework required for inhibiting tau polymerization, in addition to hydrogen bonding, hydrophilic-hydrophobic interactions, and static electrical interactions, as reported previously. The inhibitory effect of TA on human full-length tau protein (tau441) was also verified by electron microscopy. This finding hints at the possibility of TA as a leading compound of anti-AD drugs and offers a new stratagem for the rational molecular design of a tau aggregation inhibitor. PMID:23442089

  12. All-Trans Retinoic Acid Inhibits Human Colorectal Cancer Cells RKO Migration via Downregulating Myosin Light Chain Kinase Expression through MAPK Signaling Pathway.

    PubMed

    Zuo, Li; Yang, Xiaoping; Lu, Man; Hu, Ruolei; Zhu, Huaqing; Zhang, Sumei; Zhou, Qing; Chen, Feihu; Gui, Shuyu; Wang, Yuan

    2016-10-01

    All-trans-retinoic acid (ATRA) inhibits the invasive and metastatic potentials of various cancer cells. However, the underlying mechanism is unclear. Here, we demonstrate that ATRA inhibited colorectal cancer cells RKO (human colon adenocarcinoma cell) migration by downregulating cell movement and increasing cell adhesion. ATRA inhibited the expression and activation of myosin light chain kinase (MLCK) in RKO cells, while the expression level of MLC phosphatase (MLCP) had no change in RKO cells treated with or without ATRA. The expression and activity of MLC was also inhibited in RKO cells exposed to ATRA. Intriguingly, ATRA increased the expression of occludin messenger RNA (mRNA) and protein and its localization on cell membrane. However, ATRA did not change the expression of zonula occludens 1 (ZO-1), but increased the accumulation of ZO-1 on RKO cells membrane. ML-7, an inhibitor of MLCK, significantly inhibited RKO cell migration. Furthermore, knockdown of endogenous MLCK expression inhibited RKO migration. Mechanistically, we showed that MAPK-specific inhibitor PD98059 enhanced the inhibitory effect of ATRA on RKO migration. In contrast, phorbol 12-myristate 13-acetate (PMA) attenuated the effects of ATRA in RKO cells. Moreover, knocking down endogenous extracellular signal-regulated kinase (ERK) expression inhibited MLCK expression in the RKO cells. In conclusion, ATRA inhibits RKO migration by reducing MLCK expression via extracellular signal-regulated kinase 1/Mitogen-activated protein kinase (ERK1/MAPK) signaling pathway. PMID:27564600

  13. Carnosic acid attenuates unilateral ureteral obstruction-induced kidney fibrosis via inhibition of Akt-mediated Nox4 expression.

    PubMed

    Jung, Kyong-Jin; Min, Kyoung-Jin; Park, Jeen-Woo; Park, Kwon Moo; Kwon, Taeg Kyu

    2016-08-01

    Fibrosis represents a common pathway to end-stage renal disease. Transforming growth factor-β (TGF-β) plays a critical role in the progression of kidney fibrosis. In the present study, we explored the effect of carnosic acid (CA) against TGF-β-induced fibroblast activation in vitro and unilateral ureteral obstruction (UUO)-induced kidney fibrosis in vivo. CA attenuated TGF-β-induced up-regulation of profibrogenic proteins, α-smooth muscle actin (α-SMA), collagen I (COLI), fibronectin (FN), and plasminogen activator inhibitor-1 (PAI-1) in kidney fibroblast cells (NRK-49F). CA inhibited TGF-β-induced hydrogen peroxide generation via inhibition of NADPH oxidase 4 (Nox4) expressions. In mice, CA-administration markedly mitigated the UUO-induced interstitial extension, collagen deposition, superoxide anion formation, hydrogen peroxide production, and lipid peroxidation. In addition, CA significantly attenuated the expression of α-SMA, COLI, FN, PAI-1, and Nox4 in UUO-induced kidneys. These results indicated that CA attenuated oxidative stress via inhibition of Nox4 expression in TGF-β-stimulated fibroblasts and UUO operated-kidneys, suggesting that CA may be useful for the treatment of fibrosis-related diseases. PMID:27212017

  14. Gamma-irradiation of malic acid in aqueous solutions. [prebiotic significance

    NASA Technical Reports Server (NTRS)

    Negron-Mendoza, A.; Graff, R. L.; Ponnamperuma, C.

    1980-01-01

    The gamma-irradiation of malic acid in aqueous solutions was studied under initially oxygenated and oxygen-free conditions in an attempt to determine the possible interconversion of malic acid into other carboxylic acids, specifically those associated with Krebs cycle. The effect of dose on product formation of the system was investigated. Gas-liquid chromatography combined with mass spectrometry was used as the principal means of identification of the nonvolatile products. Thin layer chromatography and direct probe mass spectroscopy were also employed. The findings show that a variety of carboxylic acids are formed, with malonic and succinic acids in greatest abundance. These products have all been identified as being formed in the gamma-irradiation of acetic acid, suggesting a common intermediary. Since these molecules fit into a metabolic cycle, it is strongly suggestive that prebiotic pathways provided the basis for biological systems.

  15. Activation of the constitutive androstane receptor inhibits gluconeogenesis without affecting lipogenesis or fatty acid synthesis in human hepatocytes

    SciTech Connect

    Lynch, Caitlin; Pan, Yongmei; Li, Linhao; Heyward, Scott; Moeller, Timothy; Swaan, Peter W.; Wang, Hongbing

    2014-08-15

    Objective: Accumulating evidence suggests that activation of mouse constitutive androstane receptor (mCAR) alleviates type 2 diabetes and obesity by inhibiting hepatic gluconeogenesis, lipogenesis, and fatty acid synthesis. However, the role of human (h) CAR in energy metabolism is largely unknown. The present study aims to investigate the effects of selective hCAR activators on hepatic energy metabolism in human primary hepatocytes (HPH). Methods: Ligand-based structure–activity models were used for virtual screening of the Specs database ( (www.specs.net)) followed by biological validation in cell-based luciferase assays. The effects of two novel hCAR activators (UM104 and UM145) on hepatic energy metabolism were evaluated in HPH. Results: Real-time PCR and Western blotting analyses reveal that activation of hCAR by UM104 and UM145 significantly repressed the expression of glucose-6-phosphatase and phosphoenolpyruvate carboxykinase, two pivotal gluconeogenic enzymes, while exerting negligible effects on the expression of genes associated with lipogenesis and fatty acid synthesis. Functional experiments show that UM104 and UM145 markedly inhibit hepatic synthesis of glucose but not triglycerides in HPH. In contrast, activation of mCAR by 1,4-bis[2-(3,5-dichloropyridyloxy)]benzene, a selective mCAR activator, repressed the expression of genes associated with gluconeogenesis, lipogenesis, and fatty acid synthesis in mouse primary hepatocytes, which were consistent with previous observations in mouse model in vivo. Conclusion: Our findings uncover an important species difference between hCAR and mCAR in hepatic energy metabolism, where hCAR selectively inhibits gluconeogenesis without suppressing fatty acid synthesis. Implications: Such species selectivity should be considered when exploring CAR as a potential therapeutic target for metabolic disorders. - Highlights: • Novel hCAR activators were identified by computational and biological approaches. • The role

  16. Significance of the detection of esters of p-hydroxybenzoic acid (parabens) in human breast tumours.

    PubMed

    Harvey, Philip W; Everett, David J

    2004-01-01

    This issue of Journal of Applied Toxicology publishes the paper Concentrations of Parabens in Human Breast Tumours by Darbre et al. (2004), which reports that esters of p-hydroxybenzoic acid (parabens) can be detected in samples of tissue from human breast tumours. Breast tumour samples were supplied from 20 patients, in collaboration with the Edinburgh Breast Unit Research Group, and analysed by high-pressure liquid chromatography and tandem mass spectrometry. The parabens are used as antimicrobial preservatives in underarm deodorants and antiperspirants and in a wide range of other consumer products. The parabens also have inherent oestrogenic and other hormone related activity (increased progesterone receptor gene expression). As oestrogen is a major aetiological factor in the growth and development of the majority of human breast cancers, it has been previously suggested by Darbre that parabens and other chemicals in underarm cosmetics may contribute to the rising incidence of breast cancer. The significance of the finding of parabens in tumour samples is discussed here in terms of 1). Darbre et al's study design, 2). what can be inferred from this type of data (and what can not, such as the cause of these tumours), 3). the toxicology of these compounds and 4). the limitations of the existing toxicology database and the need to consider data that is appropriate to human exposures.

  17. Control of ACTH secretion by excitatory amino acids: functional significance and clinical implications.

    PubMed

    Jezova, Daniela

    2005-12-01

    The involvement of excitatory amino acids in the control of ACTH release is well established. Activation of ionotropic glutamate receptors has a stimulatory effect on ACTH release, while the role of metabotropic receptors is not yet understood in detail. Glutamatergic regulation of ACTH release has a clear significance for the stress response and neuroendocrine functions during development. A dysregulation of the hypothalamic-pituitary-adrenocortical (HPA) axis has been reported in several psychiatric and neurological disorders. So far, only fractional indices on the clinical importance of the interaction between glutamate and ACTH secretion have been obtained in both preclinical and clinical studies. Some antidepressant drugs, such as tianeptine, which were found to modulate ACTH release, appear to interfere with brain glutamatergic system. Changes in ACTH and cortisol release may be of importance for mood stabilizing effects of antiepileptic drugs modulating glutamate release, such as lamotrigine. Brain glutamate and HPA axis interaction seems to be of importance in alcohol and drug abuse. Little information is available on ACTH release in response to glutamate-modulating drugs used in the treatment of schizophrenia and Alzheimer disease. Nevertheless, pharmacological interventions influencing interaction between glutamate and the HPA axis are promising treatment possibilities in psychiatry and neurology.

  18. Significant effect of Ca2+ on improving the heat resistance of lactic acid bacteria.

    PubMed

    Huang, Song; Chen, Xiao Dong

    2013-07-01

    The heat resistance of lactic acid bacteria (LAB) has been extensively investigated due to its highly practical significance. Reconstituted skim milk (RSM) has been found to be one of the most effective protectant wall materials for microencapsulating microorganisms during convective drying, such as spray drying. In addition to proteins and carbohydrate, RSM is rich in calcium. It is not clear which component is critical in the RSM protection mechanism. This study investigated the independent effect of calcium. Ca(2+) was added to lactose solution to examine its influence on the heat resistance of Lactobacillus rhamnosus ZY, Lactobacillus casei Zhang, Lactobacillus plantarum P8 and Streptococcus thermophilus ND03. The results showed that certain Ca(2+) concentrations enhanced the heat resistance of the LAB strains to different extents, that is produced higher survival and shorter regrowth lag times of the bacterial cells. In some cases, the improvements were dramatic. More scientifically insightful and more intensive instrumental study of the Ca(2+) behavior around and in the cells should be carried out in the near future. In the meantime, this work may lead to the development of more cost-effective wall materials with Ca(2+) added as a prime factor. PMID:23617813

  19. Significance of the C-terminal amino acid residue in mengovirus RNA-dependent RNA polymerase.

    PubMed

    Dmitrieva, Tatiana M; Alexeevski, Andrei V; Shatskaya, Galina S; Tolskaya, Elena A; Gmyl, Anatoly P; Khitrina, Elena V; Agol, Vadim I

    2007-08-15

    Replication of picornavirus genomes is accomplished by the virally encoded RNA-dependent RNA polymerase (RdRP). Although the primary structure of this enzyme exhibits a high level of conservation, there are several significant differences among different picornavirus genera. In particular, a comparative alignment indicates that the C-terminal sequences of cardiovirus RdRP (known also as 3D(pol)), are 1-amino-acid residue (arginine or tryptophan) longer than that of the enterovirus or rhinovirus enzymes. Here, it is shown that alterations of the last codon of the RdRP-encoding sequence of mengovirus RNA leading to deletion of the C-terminal Trp460 or its replacement by Ala or Phe dramatically impaired viral RNA replication and, in the former case, resulted in a quasi-infectious phenotype (i.e., the mutant RNA might generate a low yield of pseudorevertants acquiring a Tyr residue in place of the deleted Trp460). The replacement of Trp460 by His or Tyr did not appreciably alter the viral growth potential. Homology modeling of three-dimensional structure of mengovirus RdRP suggested that Trp460 may be involved in interaction between the thumb and palm domains of the enzyme. Specifically, Trp460 of the thumb may form a hydrogen bond with Thr219 and hydrophobically interact with Val216 of the palm. The proposed interactions were consistent with the results of in vivo SELEX experiment, which demonstrated that infectious virus could contain Ser or Thr at position 219 and hydrophobic Val, Leu, Ile, as well as Arg (whose side chain has a nonpolar part) at position 216. A similar thumb-palm domain interaction may be a general feature of several RdRPs and its possible functional significance is discussed. PMID:17467026

  20. Folic acid prevents behavioral impairment and Na(+), K(+) -ATPase inhibition caused by neonatal hypoxia-ischemia.

    PubMed

    Carletti, Jaqueline Vieira; Deniz, Bruna Ferrary; Miguel, Patrícia Maidana; Rojas, Joseane Jiménez; Kolling, Janaína; Scherer, Emilene Barros; de Souza Wyse, Angela Teresinha; Netto, Carlos Alexandre; Pereira, Lenir Orlandi

    2012-08-01

    Folic acid plays an important role in neuroplasticity and acts as a neuroprotective agent, as observed in experimental brain ischemia studies. The aim of this study was to investigate the effects of folic acid on locomotor activity, aversive memory and Na(+),K(+)-ATPase activity in the frontal cortex and striatum in animals subjected to neonatal hypoxia-ischemia (HI). Wistar rats of both sexes at postnatal day 7 underwent HI procedure and were treated with intraperitoneal injections of folic acid (0.011 μmol/g body weight) once a day, until the 30th postnatal day. Starting on the day after, behavioral assessment was run in the open field and in the inhibitory avoidance task. Animals were sacrificed by decapitation 24 h after testing and striatum and frontal cortex were dissected out for Na(+),K(+)-ATPase activity analysis. Results show anxiogenic effect in the open field and an impairment of aversive memory in the inhibitory avoidance test in HI rats; folic acid treatment prevented both behavioral effects. A decreased Na(+),K(+)-ATPase activity in striatum, both ipsilateral and contralateral to ischemia, was identified after HI; a total recovery was observed in animals treated with folic acid. A partial recovery of Na(+),K(+)-ATPase activity was yet seen in frontal cortex of HI animals receiving folic acid supplementation. Presented results support that folic acid treatment prevents memory deficit and anxiety-like behavior, as well as prevents Na(+),K(+)-ATPase inhibition in the striatum and frontal cortex caused by neonatal hypoxia-ischemia.

  1. Inhibition of Interjacent Ribonucleic Acid (26S) Synthesis in Cells Infected by Sindbis Virus

    PubMed Central

    Scheele, Christina M.; Pfefferkorn, E. R.

    1969-01-01

    The interrelationship of viral ribonucleic acid (RNA) and protein synthesis in cells infected by Sindbis virus was investigated. When cultures were treated with puromycin early in the course of infection, the synthesis of interjacent RNA (26S) was preferentially inhibited. A similar result was obtained by shifting cells infected by one temperature-sensitive mutant defective in RNA synthesis from the permissive (29 C) to the nonpermissive (41.5 C) temperature. Under both conditions, the viral RNA produced appeared to be fully active biologically. Once underway, the synthesis of viral RNA in wild-type Sindbis infections did not require concomitant protein synthesis. PMID:5817400

  2. Influence of poly(aminoquinone) on corrosion inhibition of iron in acid media

    NASA Astrophysics Data System (ADS)

    Jeyaprabha, C.; Sathiyanarayanan, S.; Phani, K. L. N.; Venkatachari, G.

    2005-11-01

    The inhibitor performance of chemically synthesized water soluble poly(aminoquinone) (PAQ) on iron corrosion in 0.5 M sulphuric acid was studied in relation to inhibitor concentration using potentiodynamic polarization and electrochemical impedance spectroscopy measurements. On comparing the inhibition performance of PAQ with that of the monomer o-phenylenediamine (OPD), the OPD gave an efficiency of 80% for 1000 ppm while it was 90% for 100 ppm of PAQ. PAQ was found to be a mixed inhibitor. Besides, PAQ was able to improve the passivation tendency of iron in 0.5 M H 2SO 4 markedly.

  3. Zoledronic acid inhibits the pentose phosphate pathway through attenuating the Ras-TAp73-G6PD axis in bladder cancer cells.

    PubMed

    Wang, Xiaolin; Wu, Guang; Cao, Guangxin; Yang, Lei; Xu, Haifei; Huang, Jian; Hou, Jianquan

    2015-09-01

    Zoledronic acid (ZA) is the current standard of care for the therapy of patients with bone metastasis or osteoporosis. ZA inhibits the prenylation of small guanosine‑5'-triphosphate (GTP)‑binding proteins, such as Ras, and thus inhibit Ras signaling. The present study demonstrated that ZA inhibited cell proliferation and the pentose phosphate pathway (PPP) in bladder cancer cells. In addition, the expression of glucose‑6‑phosphate dehydrogenase (G6PD, the rate‑limiting enzyme of the PPP) was found to be inhibited by ZA. Furthermore, the stability of TAp73, which activates the expression G6PD was decreased in zoledronic acid treated cells. Decreased levels of Ras‑GTP and phosphorylated‑extracellular signal-regulated kinase 1/2 were also observed following treatment with ZA. This may be due to the fact that activated Ras was reported to stabilize TAp73 inducing its accumulation. The inhibition of Ras activity by PT inhibitor II also significantly reduced the levels of TAp73 and G6PD and the PPP flux. Moreover, knockdown of TAp73, attenuated the PPP flux and eliminated the affection of ZA on the PPP flux. In conclusion, it was proposed that ZA can inhibit stability of TAp73 and attenuate the PPP via blocking Ras signaling in bladder cancer cells.

  4. Effects of inhibition gastric acid secretion on arterial acid-base status during digestion in the toad Bufo marinus.

    PubMed

    Andersen, Johnnie B; Andrade, Denis V; Wang, Tobias

    2003-07-01

    Digestion affects acid-base status, because the net transfer of HCl from the blood to the stomach lumen leads to an increase in HCO3(-) levels in both extra- and intracellular compartments. The increase in plasma [HCO3(-)], the alkaline tide, is particularly pronounced in amphibians and reptiles, but is not associated with an increased arterial pH, because of a concomitant rise in arterial PCO2 caused by a relative hypoventilation. In this study, we investigate whether the postprandial increase in PaCO2 of the toad Bufo marinus represents a compensatory response to the increased plasma [HCO3(-)] or a state-dependent change in the control of pulmonary ventilation. To this end, we successfully prevented the alkaline tide, by inhibiting gastric acid secretion with omeprazole, and compared the response to that of untreated toads determined in our laboratory during the same period. In addition, we used vascular infusions of bicarbonate to mimic the alkaline tide in fasting animals. Omeprazole did not affect blood gases, acid-base and haematological parameters in fasting toads, but abolished the postprandial increase in plasma [HCO3(-)] and the rise in arterial PCO2 that normally peaks 48 h into the digestive period. Vascular infusion of HCO3(-), that mimicked the postprandial rise in plasma [HCO3(-)], led to a progressive respiratory compensation of arterial pH through increased arterial PCO2. Thus, irrespective of whether the metabolic alkalosis is caused by gastric acid secretion in response to a meal or experimental infusion of bicarbonate, arterial pH is being maintained by an increased arterial PCO2. It seems, therefore, that the elevated PCO2, occuring during the postprandial period, constitutes of a regulated response to maintain pH rather than a state-dependent change in ventilatory control.

  5. Abiogenic Syntheses of Lipoamino Acids and Lipopeptides and their Prebiotic Significance

    NASA Astrophysics Data System (ADS)

    Sproul, Gordon

    2015-12-01

    Researchers have formed peptide bonds under a variety of presumed prebiotic conditions. Here it is proposed that these same conditions would have also formed amide bonds between fatty acids and amino acids, producing phosphate-free amphipathic lipoamino acids and lipopeptides. These compounds are known to form vesicles and are ubiquitous in living organisms. They could represent molecules that provided protection by membranes as well as possibilities for proto-life metabolism . It is here demonstrated that when a fatty acid is heated with various amino acids, optimally in the presence of suitable salts or minerals, lipoamino acids are formed. Magnesium and potassium carbonates as well as iron (II) sulfide are found to be particularly useful in these reactions. In this manner N-lauroylglycine, N-lauroylalanine, N-stearoylalanine and several other lipoamino acids have been synthesized. Similarly, when glycylglycine was heated with lauric acid in the presence of magnesium carbonate, the lipopeptide N-lauroylglycylglycine was formed. Such compounds are proposed to have been critical precursors to the development of life.

  6. Abiogenic Syntheses of Lipoamino Acids and Lipopeptides and their Prebiotic Significance.

    PubMed

    Sproul, Gordon

    2015-12-01

    Researchers have formed peptide bonds under a variety of presumed prebiotic conditions. Here it is proposed that these same conditions would have also formed amide bonds between fatty acids and amino acids, producing phosphate-free amphipathic lipoamino acids and lipopeptides. These compounds are known to form vesicles and are ubiquitous in living organisms. They could represent molecules that provided protection by membranes as well as possibilities for proto-life metabolism . It is here demonstrated that when a fatty acid is heated with various amino acids, optimally in the presence of suitable salts or minerals, lipoamino acids are formed. Magnesium and potassium carbonates as well as iron (II) sulfide are found to be particularly useful in these reactions. In this manner N-lauroylglycine, N-lauroylalanine, N-stearoylalanine and several other lipoamino acids have been synthesized. Similarly, when glycylglycine was heated with lauric acid in the presence of magnesium carbonate, the lipopeptide N-lauroylglycylglycine was formed. Such compounds are proposed to have been critical precursors to the development of life. PMID:26248658

  7. The effect of a platelet cholesterol modulation on the acetylsalicylic acid-mediated blood platelet inhibition in hypercholesterolemic patients.

    PubMed

    Luzak, Boguslawa; Boncler, Magdalena; Rywaniak, Joanna; Wilk, Radoslaw; Stanczyk, Lidia; Czyz, Malgorzata; Rysz, Jacek; Watala, Cezary

    2011-05-11

    Aspirin (acetylsalicylic acid, ASA) is widely used in the prevention of cardiovascular disease, but its beneficial effects may be restrained in some individuals, where the reduced ability of ASA to protect against arterial thrombotic events is observed. We analyzed the influence of the treatment with atorvastatin (10mg/day) on the platelet sensitivity to ASA monitored under in vitro conditions in hypercholesterolemic patients. The associations between plasma or platelet cholesterol parameters and the ASA-mediated inhibition of platelet reactivity or the extent of platelet protein acetylation by ASA were estimated in the patients treated with atorvastatin for 1, 3, or 6 months. Out of 27 patients, in 17 individuals platelets appeared significantly more sensitive to 50 μM ASA in arachidonic acid- or collagen-induced whole blood aggregation following 1 month atorvastatin therapy (inhibition by 60.9 ± 5.6% vs. 48.8 ± 5.4%, P<0.05 for 0.5mM arachidonic acid, 40.8 ± 2.9% vs. 27.0 ± 4.1%, P<0.05 for 1 μg/ml collagen), and this effect lasted for 3 and 6 months, remaining in a weak, although significant, relation to the reduction of platelet cholesterol content (R(S)=-0.277, P<0.002 for arachidonic acid, R(S)=-0.197, P<0.02 for collagen). It was, however, not dependent upon either antiplatelet action or plasma lipid-lowering activity of atorvastatin. In addition, in about 50% of patients, we noticed that ASA (50 μM) significantly and time-dependently diminished thromboxane B(2) concentration in atorvastatin-treated patients. The ASA-induced acetylation of platelet proteins significantly increased in the course of atorvastatin therapy and was associated with reduced platelet cholesterol (R(S)=-0.598, P<0.0001). In conclusion, statin therapy may improve platelet sensitivity to ASA in some hypercholesterolemic patients. This effect may extend beyond the action of atorvastatin as merely a lipid-lowering agent. The mechanisms of resistance of some patients to such a

  8. Inhibition of Helicobacter pylori binding to gastrointestinal epithelial cells by sialic acid-containing oligosaccharides.

    PubMed Central

    Simon, P M; Goode, P L; Mobasseri, A; Zopf, D

    1997-01-01

    Helicobacterpylori, the ulcer pathogen residing in the human stomach, binds to epithelial cells of the gastric antrum. We have examined binding of 13 bacterial isolates to epithelial cell lines by use of a sensitive microtiter plate method in which measurement of bacterial urease activity provides the means for quantitation of bound organisms. Several established human gastrointestinal carcinoma cell lines grown as monolayers were compared for suitability in these assays, and the duodenum-derived cell line HuTu-80 was selected for testing bacterial binding inhibitors. When bacteria are pretreated with oligosaccharides, glycoproteins, and glycolipids, a complex picture of bacterial-epithelial adherence specificities emerges. Among the monovalent inhibitors tested, 3'-sialyllactose (NeuAc alpha2-3Gal beta1-4Glc; 3'SL) was the most active oligosaccharide, inhibiting adherence for recent clinical isolates of H. pylori with a millimolar 50% inhibitory concentration (IC50). Its alpha2-6 isomer (6'SL) was less active. Most of the recent clinical isolates examined were inhibited by sialyllactose, whereas long-passaged isolates were insensitive. Among the long-passaged bacterial strains whose binding was not inhibited by 3'SL was the strain ATCC 43504, also known as NCTC 11637 and CCUG 17874, in which the proposed sialyllactose adhesin was recently reported to lack surface expression (P. G. O'Toole, L. Janzon, P. Doig, J. Huang, M. Kostrzynska, and T. H. Trust, J. Bacteriol. 177:6049-6057, 1995). Pretreatment of the epithelial monolayer with neuraminidase reduced the extent of binding by those bacteria that are sensitive to inhibition by 3'SL. Other potent inhibitors of bacterial binding are the glycoproteins alpha1-acid glycoprotein, fetuin, porcine gastric and bovine submaxillary mucins, and the glycolipid sulfatide, all of which present multivalent sialylated and/or sulfated galactosyl residues under the conditions of the binding assay. Consistent with this pattern, a

  9. Inhibition of Pseudomonas aeruginosa biofilm formation by 2,2’-bipyridyl, lipoic, kojic and picolinic acids

    PubMed Central

    Çevik, Kübra; Ulusoy, Seyhan

    2015-01-01

    Objective(s): The inhibitory effects of iron chelators, and FeCl3 chelation on biofilm formation and swarming motility were investigated against an opportunistic human pathogen Pseudomonas aeruginosa. Materials and Methods: The inhibitory activity of 2,2’-bipyridyl, lipoic acid, kojic acid and picolinic acid on biofilm formation of P. aeruginosa strain PAO1 and three clinical isolates (P. aeruginosa PAK01, P. aeruginosa PAK02 and P. aeruginosa PAK03) were investigated, based on crystal violet assay, and swarming motility test. Results: The kojic, lipoic and picolinic acid inhibited biofilm formation by 5-33% in all tested P. aeruginosa isolates. When chelated iron was added, biofilm inhibition rates were determined to be 39-57%. Among the tested chelators against P. aeruginosa, lipoic acid (84%) and kojic acid (68%) presented the highest inhibition of swarming motility. This is the first study to report the inhibitory effect of lipoic acid on biofilm formation and swarming motility of P. aeruginosa. Conclusion: It is considered that lipoic and picolinic acids can serve as alternatives for the treatment of the P. aeruginosa infections by inhibiting biofilm formation. PMID:26557964

  10. Effect of pH alkaline salts of fatty acids on the inhibition of bacteria associated with poultry processing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The agar diffusion assay was used to examine the effect of pH on the ability of alkaline salts of three fatty acids (FA) to inhibit growth of bacteria associated with poultry processing. FA solutions were prepared by dissolving 0.5 M concentrations of caprylic, capric, or lauric acid in separate ali...

  11. Inhibition profile of a series of phenolic acids on bovine lactoperoxidase enzyme.

    PubMed

    Sarikaya, S Beyza Ozturk; Sisecioglu, Melda; Cankaya, Murat; Gulcin, İlhami; Ozdemir, Hasan

    2015-06-01

    Lactoperoxidase (LPO) catalyzes the oxidation of numerous of organic and inorganic substrates by hydrogen peroxide. It has very vital activity in the innate immune system by decreasing or stopping the activation of the bacteria in milk and mucosal secretions. This study's purpose was to investigate in vitro effect of some phenolic acids (ellagic, gallic, ferulic, caffeic, quercetin, p-coumaric, syringic, catechol and epicatechin) on the purified LPO. This enzyme was purified from milk by using different methods such as Amberlite CG-50 resin, CM-Sephadex C-50 ion-exchange and Sephadex G-100 gel filtration chromatography. LPO was purified 28.7-fold with a yield of 20.03%. We found phenolic acids have inhibition effects on bovine LPO enzyme to different concentrations. Our study showed lower concentrations of caffeic acid, ferulic acid and quercetin exhibited much higher inhibitory effect on enzyme, so these three of them were clearly a more potent inhibitor than the others were. All of compounds were non-competitive inhibitors.

  12. Antibacterial activity of lichen secondary metabolite usnic acid is primarily caused by inhibition of RNA and DNA synthesis.

    PubMed

    Maciąg-Dorszyńska, Monika; Węgrzyn, Grzegorz; Guzow-Krzemińska, Beata

    2014-04-01

    Usnic acid, a compound produced by various lichen species, has been demonstrated previously to inhibit growth of different bacteria and fungi; however, mechanism of its antimicrobial activity remained unknown. In this report, we demonstrate that usnic acid causes rapid and strong inhibition of RNA and DNA synthesis in Gram-positive bacteria, represented by Bacillus subtilis and Staphylococcus aureus, while it does not inhibit production of macromolecules (DNA, RNA, and proteins) in Escherichia coli, which is resistant to even high doses of this compound. However, we also observed slight inhibition of RNA synthesis in a Gram-negative bacterium, Vibrio harveyi. Inhibition of protein synthesis in B. subtilis and S. aureus was delayed, which suggest indirect action (possibly through impairment of transcription) of usnic acid on translation. Interestingly, DNA synthesis was halted rapidly in B. subtilis and S. aureus, suggesting interference of usnic acid with elongation of DNA replication. We propose that inhibition of RNA synthesis may be a general mechanism of antibacterial action of usnic acid, with additional direct mechanisms, such as impairment of DNA replication in B. subtilis and S. aureus.

  13. Metformin reduces lipid accumulation in macrophages by inhibiting FOXO1-mediated transcription of fatty acid-binding protein 4

    SciTech Connect

    Song, Jun; Ren, Pingping; Zhang, Lin; Wang, Xing Li; Chen, Li; Shen, Ying H.

    2010-02-26

    Objective: The accumulation of lipids in macrophages contributes to the development of atherosclerosis. Strategies to reduce lipid accumulation in macrophages may have therapeutic potential for preventing and treating atherosclerosis and cardiovascular complications. The antidiabetic drug metformin has been reported to reduce lipid accumulation in adipocytes. In this study, we examined the effects of metformin on lipid accumulation in macrophages and investigated the mechanisms involved. Methods and results: We observed that metformin significantly reduced palmitic acid (PA)-induced intracellular lipid accumulation in macrophages. Metformin promoted the expression of carnitine palmitoyltransferase I (CPT-1), while reduced the expression of fatty acid-binding protein 4 (FABP4) which was involved in PA-induced lipid accumulation. Quantitative real-time PCR showed that metformin regulates FABP4 expression at the transcriptional level. We identified forkhead transcription factor FOXO1 as a positive regulator of FABP4 expression. Inhibiting FOXO1 expression with FOXO1 siRNA significantly reduced basal and PA-induced FABP4 expression. Overexpression of wild-type FOXO1 and constitutively active FOXO1 significantly increased FABP4 expression, whereas dominant negative FOXO1 dramatically decreased FABP4 expression. Metformin reduced FABP4 expression by promoting FOXO1 nuclear exclusion and subsequently inhibiting its activity. Conclusions: Taken together, these results suggest that metformin reduces lipid accumulation in macrophages by repressing FOXO1-mediated FABP4 transcription. Thus, metformin may have a protective effect against lipid accumulation in macrophages and may serve as a therapeutic agent for preventing and treating atherosclerosis in metabolic syndrome.

  14. Quercetin induces HepG2 cell apoptosis by inhibiting fatty acid biosynthesis

    PubMed Central

    ZHAO, PENG; MAO, JUN-MIN; ZHANG, SHU-YUN; ZHOU, ZE-QUAN; TAN, YANG; ZHANG, YU

    2014-01-01

    Quercetin can inhibit the growth of cancer cells with the ability to act as a ‘chemopreventer’. Its cancer-preventive effect has been attributed to various mechanisms, including the induction of cell-cycle arrest and/or apoptosis, as well as its antioxidant functions. Quercetin can also reduce adipogenesis. Previous studies have shown that quercetin has potent inhibitory effects on animal fatty acid synthase (FASN). In the present study, activity of quercetin was evaluated in human liver cancer HepG2 cells. Intracellular FASN activity was calculated by measuring the absorption of NADPH via a spectrophotometer. MTT assay was used to test the cell viability, immunoblot analysis was performed to detect FASN expression levels and the apoptotic effect was detected by Hoechst 33258 staining. In the present study, it was found that quercetin could induce apoptosis in human liver cancer HepG2 cells with overexpression of FASN. This apoptosis was accompanied by the reduction of intracellular FASN activity and could be rescued by 25 or 50 μM exogenous palmitic acids, the final product of FASN-catalyzed synthesis. These results suggested that the apoptosis induced by quercetin was via the inhibition of FASN. These findings suggested that quercetin may be useful for preventing human liver cancer. PMID:25009654

  15. Computational insights into function and inhibition of fatty acid amide hydrolase.

    PubMed

    Palermo, Giulia; Rothlisberger, Ursula; Cavalli, Andrea; De Vivo, Marco

    2015-02-16

    The Fatty Acid Amide Hydrolase (FAAH) enzyme is a membrane-bound serine hydrolase responsible for the deactivating hydrolysis of a family of naturally occurring fatty acid amides. FAAH is a critical enzyme of the endocannabinoid system, being mainly responsible for regulating the level of its main cannabinoid substrate anandamide. For this reason, pharmacological inhibition of FAAH, which increases the level of endogenous anandamide, is a promising strategy to cure a variety of diseases including pain, inflammation, and cancer. Much structural, mutagenesis, and kinetic data on FAAH has been generated over the last couple of decades. This has prompted several informative computational investigations to elucidate, at the atomic-level, mechanistic details on catalysis and inhibition of this pharmaceutically relevant enzyme. Here, we review how these computational studies - based on classical molecular dynamics, full quantum mechanics, and hybrid QM/MM methods - have clarified the binding and reactivity of some relevant substrates and inhibitors of FAAH. We also discuss the experimental implications of these computational insights, which have provided a thoughtful elucidation of the complex physical and chemical steps of the enzymatic mechanism of FAAH. Finally, we discuss how computations have been helpful for building structure-activity relationships of potent FAAH inhibitors. PMID:25240419

  16. Short-chain fatty acids inhibit intestinal trefoil factor gene expression in colon cancer cells.

    PubMed

    Tran, C P; Familari, M; Parker, L M; Whitehead, R H; Giraud, A S

    1998-07-01

    Intestinal trefoil factor (ITF) gene expression was detected in five colon cancer cell lines. ITF was synthesized by mucous cells of LIM 1215 and LIM 1863 lines, from which it is secreted constitutively. The ITF mRNA transcript was estimated to be 0.6 kb. In LIM 1215 cells, the expression of ITF was potently and dose-dependently inhibited by short-chain fatty acids (butyrate > propionate > acetate) within 8 h of application. The inhibitory effect of butyrate was ablated by actinomycin D and preceded its effects on differentiation of LIM 1215 cells as indicated by induction of alkaline phosphatase activity and counting of periodic acid-Schiff-positive cells. The human ITF promoter contained an 11-residue consensus sequence with high homology to the butyrate response element of the cyclin D1 gene. Mobility shift assays show specific binding of this response element to nuclear protein extracts of LIM 1215 cells. We conclude that butyrate inhibits ITF expression in colon cancer cells and that this effect may be mediated transcriptionally and independently of its effects on differentiation.

  17. Tributyltin and triphenyltin inhibit osteoclast differentiation through a retinoic acid receptor-dependent signaling pathway

    SciTech Connect

    Yonezawa, Takayuki; Hasegawa, Shin-ichi; Ahn, Jae-Yong; Cha, Byung-Yoon; Teruya, Toshiaki; Hagiwara, Hiromi; Nagai, Kazuo; Woo, Je-Tae; E-mail: jwoo@isc.chubu.ac.jp

    2007-03-30

    Organotin compounds, such as tributyltin (TBT) and triphenyltin (TPT), have been widely used in agriculture and industry. Although these compounds are known to have many toxic effects, including endocrine-disrupting effects, their effects on bone resorption are unknown. In this study, we investigated the effects of organotin compounds, such as monobutyltin (MBT), dibutyltin (DBT), TBT, and TPT, on osteoclast differentiation using mouse monocytic RAW264.7 cells. MBT and DBT had no effects, whereas TBT and TPT dose-dependently inhibited osteoclast differentiation at concentrations of 3-30 nM. Treatment with a retinoic acid receptor (RAR)-specific antagonist, Ro41-5253, restored the inhibition of osteoclastogenesis by TBT and TPT. TBT and TPT reduced receptor activator of nuclear factor-{kappa}B ligand (RANKL) induced nuclear factor of activated T cells (NFAT) c1 expression, and the reduction in NFATc1 expression was recovered by Ro41-5253. Our results suggest that TBT and TPT suppress osteoclastogenesis by inhibiting RANKL-induced NFATc1 expression via an RAR-dependent signaling pathway.

  18. Inhibition of Collagenase by Mycosporine-like Amino Acids from Marine Sources

    PubMed Central

    Hartmann, Anja; Gostner, Johanna; Fuchs, Julian E.; Chaita, Eliza; Aligiannis, Nektarios; Skaltsounis, Leandros; Ganzera, Markus

    2015-01-01

    Matrix metalloproteinases (MMP) play an important role in extracellular matrix remodeling. Excessive activity of these enzymes can be induced by UV light and leads to skin damage, a process known as photoaging. In this study we investigated the collagenase inhibition potential of mycosporine-like amino acids (MAA), compounds that have been isolated from marine organisms and are known photoprotectants against UV-A and UV-B. For this purpose the commonly used collagenase assay was optimized and for the first time validated in terms of relationships between enzyme-substrate concentrations, temperature, incubation time and enzyme stability. Three compounds were isolated from the marine red algae Porphyra sp. and Palmaria palmata, and evaluated for their inhibitory properties against Chlostridium histolyticum collagenase (Chc). A dose-dependent, but very moderate inhibition was observed for all substances and IC50 values of 104.0 μM for shinorine, 105.9 μM for porphyra and 158.9 μM for palythine were determined. Additionally, computer-aided docking models suggested that the MAA binding to the active site of the enzyme is a competitive inhibition. PMID:26039265

  19. Nordihydroguaiaretic Acid Inhibits an Activated FGFR3 Mutant, and Blocks Downstream Signaling in Multiple Myeloma Cells

    PubMed Central

    Meyer, April N.; McAndrew, Christopher W.; Donoghue, Daniel J.

    2008-01-01

    Activating mutations within Fibroblast Growth Factor Receptor 3 (FGFR3), a receptor tyrosine kinase, are responsible for human skeletal dysplasias including achondroplasia and the neonatal lethal syndromes, Thanatophoric Dysplasia (TD) type I and II. Several of these same FGFR3 mutations have also been identified somatically in human cancers, including multiple myeloma, bladder carcinoma and cervical cancer. Based on reports that strongly activated mutants of FGFR3 such as the TDII (K650E) mutant signal preferentially from within the secretory pathway, the inhibitory properties of nordihydroguaiaretic acid (NDGA), which blocks protein transport through the Golgi, were investigated. NDGA was able to inhibit FGFR3 autophosphorylation both in vitro and in vivo. In addition, signaling molecules downstream of FGFR3 activation such as STAT1, STAT3 and MAPK were inhibited by NDGA treatment. Using HEK293 cells expressing activated FGFR3-TDII, together with several multiple myeloma cell lines expressing activated forms of FGFR3, NDGA generally resulted in a decrease in MAPK activation by 1 hour, and resulted in increased apoptosis over 24 hours. The effects of NDGA on activated FGFR3 derivatives targeted either to the plasma membrane or the cytoplasm were also examined. These results suggest that inhibitory small molecules such as NDGA that target a specific subcellular compartment may be beneficial in the inhibition of activated receptors such as FGFR3 that signal from the same compartment. PMID:18794123

  20. Rosmarinic acid and arbutin suppress osteoclast differentiation by inhibiting superoxide and NFATc1 downregulation in RAW 264.7 cells

    PubMed Central

    OMORI, AKINA; YOSHIMURA, YOSHITAKA; DEYAMA, YOSHIAKI; SUZUKI, KUNIAKI

    2015-01-01

    The present study investigated the effect of the natural polyphenols, rosmarinic acid and arbutin, on osteoclast differentiation in RAW 264.7 cells. Rosmarinic acid and arbutin suppressed osteoclast differentiation and had no cytotoxic effect on osteoclast precursor cells. Rosmarinic acid and arbutin inhibited superoxide production in a dose-dependent manner. mRNA expression of the master regulator of osteoclastogenesis, nuclear factor of activated T cells cytoplasmic 1 (NFATc1) and the osteoclast marker genes, matrix metalloproteinase-9, tartrate-resistant acid phosphatase and cathepsin-K, decreased following treatments with rosmarinic acid and arbutin. Furthermore, resorption activity decreased with the number of osteoclasts. These results suggest that rosmarinic acid and arbutin may be useful for the prevention and treatment of bone diseases, such as osteoporosis, through mechanisms involving inhibition of superoxide and downregulation of NFATc1. PMID:26171153

  1. Inhibition of acid production in coal refuse amended with CaSO{sub 3}-based flue gas desulfurization by-products

    SciTech Connect

    Hao, Y.; Dick, W.A.; Beeghly, J.

    1998-12-31

    Oxidation of pyrite in coal refuse produces acid which caused environmental degradation. Some flue gas desulfurization (FGD) by-products contain calcium sulfite (CaSO{sub 3}) which is a strong reductant. Calcium sulfite competes with pyrite for oxygen resulting in inhibition of pyrite oxidation. In addition fly ash, CaCO{sub 3} and CaSO{sub 3} in FGD can neutralize acidity. Coal refuse, amended with FGD or its components, was packed into columns (2.5 x 13 cm) and leached weekly with water for 13 weeks. The pH, titratable acidity, and concentrations of Al, As, B, Ca, Fe, Pb, S, Se, were determined. The FGD containing CaSO{sub 2} inhibited acid production in coal refuse. The final leachate for FGD treatment had a pH of 5.3 and 20 mM of acidity (hydrogen ion) as compared to a pH of 1.7 and acidity of 480 mM for the control. Compared to the control, the FGD treatment yielded loser concentrations of all elements except for B and Ca. There was an interaction between all the components in the FGD and an indication that alterations of the ratio of components in FGD may significantly improve their inhibitory effect on acid production in coal refuse.

  2. The Apollo program and amino acids. [precursors significance in molecular evolution

    NASA Technical Reports Server (NTRS)

    Fox, S. W.

    1973-01-01

    Apollo lunar sample analyses designed to detect the presence of organic compounds are reviewed, and the results are discussed from the viewpoint of relevance to laboratory experiments on the synthesis of amino acids and to theoretical models of cosmochemical processes resulting in the formation of organic compounds. Glycine, alanine, glutamic acid, aspartic acid, serine, and threonine have been found repeatedly in the hydrolyzates of hot aqueous extracts of lunar dust. These compounds represent an early step in the sequence of events leading to the rise of living material and were probably deposited by the solar wind. The results of the Apollo program so far suggest that the pathway from cosmic organic matter to life as it evolved on earth could have been pursued on the moon to the stage of amino acid precursors and then may have been terminated for lack of sufficient water.

  3. Occurrence of 3-hydroxy acids in microalgae and cyanobacteria and their geochemical significance

    NASA Astrophysics Data System (ADS)

    Matsumoto, Genki I.; Nagashima, Hideyuki

    1984-08-01

    3-Hydroxy acids were detected in pure cultured microalgae: Chlorophyta— Chlamydomonas reinhardtii and Chlorella pyrenoidosa and Rhodophyta— Cyanidium caldarium (two strains), and cyanobacteria (Cyanophyta)— Anacystis nidulans, Phormidium foveolarum, Anabaena variabilis and Oscillatoria sp. Normal and branched (iso and anteiso) 3-hydroxy acids in the ranges of C 8-C 26 were found in all the samples studied at concentrations ranging from 0.036 to 2.3 and 0.000 to 0.12 mg g -1 of dry sample, respectively. The major constituents were generally even-carbon numbered normal acids with carbon chain lengths below C 20. Microalgae and cyanobacteria may be the important sources of 3-hydroxy acids in natural environments.

  4. Novel off-target effect of tamoxifen--inhibition of acid ceramidase activity in cancer cells.

    PubMed

    Morad, Samy A F; Levin, Jonathan C; Tan, Su-Fern; Fox, Todd E; Feith, David J; Cabot, Myles C

    2013-12-01

    Acid ceramidase (AC), EC 3.5.1.23, a lysosomal enzyme, catalyzes the hydrolysis of ceramide to constituent sphingoid base, sphingosine, and fatty acid. Because AC regulates the levels of pro-apoptotic ceramide and mitogenic sphingosine-1-phosphate, it is considered an apt target in cancer therapy. The present study reveals, for the first time, that the prominent antiestrogen, tamoxifen, is a pan-effective AC inhibitor in the low, single digit micromolar range, as demonstrated in a wide spectrum of cancer cell types, prostate, pancreatic, colorectal, and breast. Prostate cancer cells were chosen for the detailed investigations. Treatment of intact PC-3 cells with tamoxifen produced time- and dose-dependent inhibition of AC activity. Tamoxifen did not impact cell viability nor did it inhibit AC activity in cell-free assays. In pursuit of mechanism of action, we demonstrate that tamoxifen induced time-, as early as 5min, and dose-dependent, as low as 5μM, increases in lysosomal membrane permeability (LMP), and time- and dose-dependent downregulation of AC protein expression. Assessing various protease inhibitors revealed that a cathepsin B inhibitor blocked tamoxifen-elicited downregulation of AC protein; however, this action failed to restore AC activity unless assayed in a cell-free system at pH4.5. In addition, pretreatment with tamoxifen inhibited PC-3 cell migration. Toremifene, an antiestrogen structurally similar to tamoxifen, was also a potent inhibitor of AC activity. This study reveals a new, off-target action of tamoxifen that may be of benefit to enhance anticancer therapies that either incorporate ceramide or target ceramide metabolism. PMID:23939396

  5. Acid extrusion is induced by osteoclast attachment to bone. Inhibition by alendronate and calcitonin.

    PubMed Central

    Zimolo, Z; Wesolowski, G; Rodan, G A

    1995-01-01

    Acid extrusion is essential for osteoclast (OC) activity. We examined Na+ and HCO3(-)-independent H+ extrusion in rat- and mouse OCs by measuring intracellular pH (pHi) changes, with the pHi indicator BCECF (biscarboxyethyl-5-(6) carboxyfluorescein) after H+ loading with an ammonium pulse. 90% of OCs attached to glass do not possess HCO3- and Na(+)-independent H(+)-extrusion (rate of pHi recovery = 0.043 +/- 0.007 (SEM) pH U/min, n = 26). In contrast, in OCs attached to bone, the pHi recovery rate is 0.228 +/- 0.011 pHi U/min, n = 25. OCs on bone also possess a NH(4+)-permeable pathway not seen on glass. The bone-induced H+ extrusion was inhibited by salmon calcitonin (10(-8) M, for 2 h), and was not present after pretreating the bone slices with the aminobisphosphonate alendronate (ALN). At ALN levels of 0.22 nmol/mm2 bone, H+ extrusion was virtually absent 12 h after cell seeding (0.004 +/- 0.002 pH U/min) and approximately 50% inhibition was observed at 0.022 pmol ALN/mm2 bone. The Na(+)-independent H+ extrusion was not inhibited by bafilomycin A1 (up to 10(-7) M), although a bafilomycin A1 (10(-8) M)-sensitive H+ pump was present in membrane vesicles isolated from these osteoclasts. These findings indicate that Na(+)-independent acid extrusion is stimulated by osteoclast attachment to bone and is virtually absent when bone is preincubated with ALN, or when osteoclasts are treated with salmon calcitonin. Images PMID:7593614

  6. A novel injection strategy of flurbiprofen axetil by inhibiting protein binding with 6-methoxy-2-naphthylacetic acid.

    PubMed

    Ogata, Kenji; Takamura, Norito; Tokunaga, Jin; Ikeda, Tetsuya; Setoguchi, Nao; Tanda, Kazuhiro; Yamasaki, Tetsuo; Nishio, Toyotaka; Kawai, Keiichi

    2016-04-01

    Flurbiprofen axetil (FPA) is an injection product and a prodrug of a non-steroidal anti-inflammatory drug (NSAID). After injection, it is rapidly hydrolyzed to the active form, flurbiprofen (FP). Since frequent injections of FPA can lead to abnormal physiology, an administration strategy is necessary to ensure there is enhancement of the analgesic efficiency of FP after a single dose and to reduce the total number of doses. FP strongly binds to site II of albumin, and thus the free (unbound) FP concentration is low. This study focused on 6-methoxy-2-naphthylacetic acid (6-MNA), the active metabolite of nabumetone (a prodrug of NSAID). We performed ultrafiltration experiments and pharmacokinetics analysis in rats to investigate whether the inhibitory effect of 6-MNA on FP binding to albumin increased the free FP concentration in vitro and in vivo. Results indicated that 6-MNA inhibited the binding of FP to albumin competitively. When 6-MNA was injected in rats, there was a significant increase in the free FP concentration and the area under concentration-time curve (AUC) calculated from the free FP concentration, while there was a significant decrease in the total (bound + free) FP concentration and the AUC calculated from the total FP concentration. These findings indicate that 6-MNA inhibits the protein binding of FP in vivo. This suggests that the frequency of FPA injections can be reduced when administered with nabumetone, as there is increase in the free FP concentration associated with pharmacological effect.

  7. Inhibition of fatty-acid amide hydrolase accelerates acquisition and extinction rates in a spatial memory task.

    PubMed

    Varvel, Stephen A; Wise, Laura E; Niyuhire, Floride; Cravatt, Benjamin F; Lichtman, Aron H

    2007-05-01

    Recent reports have demonstrated that disruption of CB(1) receptor signaling impairs extinction of learned responses in conditioned fear and Morris water maze paradigms. Here, we test the hypothesis that elevating brain levels of the endogenous cannabinoid anandamide through either genetic deletion or pharmacological inhibition of its primary catabolic enzyme fatty-acid amide hydrolase (FAAH) will potentiate extinction in a fixed platform water maze task. FAAH (-/-) mice and mice treated with the FAAH inhibitor OL-135, did not display any memory impairment or motor disruption, but did exhibit a significant increase in the rate of extinction. Unexpectedly, FAAH-compromised mice also exhibited a significant increase in acquisition rate. The CB(1) receptor antagonist SR141716 (rimonabant) when given alone had no effects on acquisition, but disrupted extinction. Additionally, SR141716 blocked the effects of OL-135 on both acquisition and extinction. Collectively, these results indicate that endogenous anandamide plays a facilitatory role in extinction through a CB(1) receptor mechanism of action. In contrast, the primary psychoactive constituent of marijuana, Delta(9)-tetrahydrocannabinol, failed to affect extinction rates, suggesting that FAAH is a more effective target than a direct acting CB(1) receptor agonist in facilitating extinction. More generally, these findings suggest that FAAH inhibition represents a promising pharmacological approach to treat psychopathologies hallmarked by an inability to extinguish maladaptive behaviors, such as post-traumatic stress syndrome and obsessive-compulsive disorder.

  8. Betulinic acid, a bioactive pentacyclic triterpenoid, inhibits skeletal-related events induced by breast cancer bone metastases and treatment

    SciTech Connect

    Park, Se Young; Kim, Hyun-Jeong; Kim, Ki Rim; Lee, Sun Kyoung; Lee, Chang Ki; Park, Kwang-Kyun Chung, Won-Yoon

    2014-03-01

    Many breast cancer patients experience bone metastases and suffer skeletal complications. The present study provides evidence on the protective and therapeutic potential of betulinic acid on cancer-associated bone diseases. Betulinic acid is a naturally occurring triterpenoid with the beneficial activity to limit the progression and severity of cancer, diabetes, cardiovascular diseases, atherosclerosis, and obesity. We first investigated its effect on breast cancer cells, osteoblastic cells, and osteoclasts in the vicious cycle of osteolytic bone metastasis. Betulinic acid reduced cell viability and the production of parathyroid hormone-related protein (PTHrP), a major osteolytic factor, in MDA-MB-231 human metastatic breast cancer cells stimulated with or without tumor growth factor-β. Betulinic acid blocked an increase in the receptor activator of nuclear factor-kappa B ligand (RANKL)/osteoprotegerin ratio by downregulating RANKL protein expression in PTHrP-treated human osteoblastic cells. In addition, betulinic acid inhibited RANKL-induced osteoclastogenesis in murine bone marrow macrophages and decreased the production of resorbed area in plates with a bone biomimetic synthetic surface by suppressing the secretion of matrix metalloproteinase (MMP)-2, MMP-9, and cathepsin K in RANKL-induced osteoclasts. Furthermore, oral administration of betulinic acid inhibited bone loss in mice intra-tibially inoculated with breast cancer cells and in ovariectomized mice causing estrogen deprivation, as supported by the restored bone morphometric parameters and serum bone turnover markers. Taken together, these findings suggest that betulinic acid may have the potential to prevent bone loss in patients with bone metastases and cancer treatment-induced estrogen deficiency. - Highlights: • Betulinic acid reduced PTHrP production in human metastatic breast cancer cells. • Betulinic acid blocked RANKL/OPG ratio in PTHrP-stimulated human osteoblastic cells. • Betulinic

  9. Hyaluronic acid abrogates ethanol-dependent inhibition of collagen biosynthesis in cultured human fibroblasts

    PubMed Central

    Donejko, Magdalena; Przylipiak, Andrzej; Rysiak, Edyta; Miltyk, Wojciech; Galicka, Elżbieta; Przylipiak, Jerzy; Zaręba, Ilona; Surazynski, Arkadiusz

    2015-01-01

    Introduction The aim of the study was to evaluate the effect of ethanol on collagen biosynthesis in cultured human skin fibroblasts, and the role of hyaluronic acid (HA) in this process. Regarding the mechanism of ethanol action on human skin fibroblasts we investigated: expression of β1 integrin and insulin-like growth factor 1 receptor (IGF-IR), signaling pathway protein expression: mitogen-activated protein kinases (MAPKs), protein kinase B (Akt), nuclear factor kappa B (NF-κB) transcription factor, cytotoxicity assay and apoptosis, metalloproteinase activity, as well as the influence of HA on these processes. Materials and methods Collagen biosynthesis, activity of prolidase, DNA biosynthesis, and cytotoxicity were measured in confluent human skin fibroblast cultures that have been treated with 25, 50, and 100 mM ethanol and with ethanol and 500 µg/mL HA. Western blot analysis and zymography were performed to evaluate expression of collagen type I, β1 integrin receptor, IGF-IR, NF-κB protein, phospho-Akt protein, kinase MAPK, caspase 9 activity, and matrix metalloproteinases (MMP-9 and MMP-2). Results Ethanol in a dose-dependent manner lead to the impairment of collagen biosynthesis in fibroblast cultures through decreasing prolidase activity and expression of β1 integrin and IGF-IR. This was accompanied by an increased cytotoxicity, apoptosis and lowered expression of the signaling pathway proteins induced by β1 integrin and IGF-IR, that is, MAPK (ERK1/2) kinases. The lowered amount of synthesized collagen and prolidase activity disturbance may also be due to the activation of NF-κB transcription factor, which inhibits collagen gene expression. It suggests that the decrease in fibroblast collagen production may be caused by the disturbance in its biosynthesis but not degradation. The application of HA has a protective effect on disturbances caused by the examined substances. It seems that regulatory mechanism of ethanol-induced collagen aberration take

  10. Cyclosporin A affects the bioavailability of ginkgolic acids via inhibition of P-gp and BCRP.

    PubMed

    Li, Li; Yao, Qing-Qing; Xu, Si-Yun; Hu, Hai-Hong; Shen, Qi; Tian, Ye; Pan, Lan-Ying; Zhou, Hui; Jiang, Hui-di; Lu, Chuang; Yu, Lu-Shan; Zeng, Su

    2014-11-01

    Ginkgolic acids (GAs) in natural product Ginkgobiloba L. are the pharmacological active but also toxic components. Two compounds, GA (C15:1) and GA (C17:1) are the most abundant GAs. In this study, several in vitro and in vivo models were applied to investigate transport mechanism of GAs. A rapid and sensitive LC-MS/MS method for the simultaneous determination of GA (C15:1) and GA (C17:1) was applied to analyze the biological specimens. The Papp(AP→BL) values of GA (C15:1) and GA (C17:1) were 1.66-2.13×10(-)(6)cm/s and 1.34-1.85×10(-)(6)cm/s determined using MDCK and MDCK-MDR1 cell monolayers, respectively. The Papp(BL→AP) were remarkably greater in the MDCK-MDR1 cell line, which were 6.77-11.2×10(-)(6)cm/s for GA (C15:1) and 4.73-5.15×10(-)(6)cm/s for GA (C17:1). Similar results were obtained in LLC-PK1 and LLC-PK1-BCRP cell monolayers. The net efflux ratio of GA (C15:1) and GA (C17:1) in both cell models was greater than 2 and markedly reduced by the presence of Cyclosporin A (CsA) or GF120918, inhibitors of P-gp and BCRP, suggesting that GAs are P-gp and BCRP substrates. The results from a rat bioavailability study also showed that co-administrating CsA intravenously (20mg/kg) could significantly increase GA (C15:1) and GA (C17:1) AUC0-t by 1.46-fold and 1.53-fold and brain concentration levels of 1.43-fold and 1.51-fold, respectively, due to the inhibition of P-gp and BCRP efflux transporters by CsA.

  11. 18{beta}-Glycyrrhetinic acid inhibits adipogenic differentiation and stimulates lipolysis

    SciTech Connect

    Moon, Myung-Hee; Jeong, Jae-Kyo; Lee, You-Jin; Seol, Jae-Won; Ahn, Dong-Choon; Kim, In-Shik; Park, Sang-Youel

    2012-04-20

    Highlights: Black-Right-Pointing-Pointer 18{beta}-GA inhibits adipogenic differentiation in 3T3-L1 preadipocytes and stimulates lipolysis in differentiated adipocytes. Black-Right-Pointing-Pointer Anti-adipogenic effect of 18{beta}-GA is caused by down-regulation of PPAR{gamma} and inactivation of Akt signalling. Black-Right-Pointing-Pointer Lipolytic effect of 18{beta}-GA is mediated by up-regulation of HSL, ATGL and perilipin and activation of HSL. -- Abstract: 18{beta}-Glycyrrhetinic acid (18{beta}-GA) obtained from the herb liquorice has various pharmacological properties including anti-inflammatory and anti-bacterial activities. However, potential biological anti-obesity activities are unclear. In this study, novel biological activities of 18{beta}-GA in the adipogenesis of 3T3-L1 preadipocytes and in lipolysis of differentiated adipocytes were identified. Mouse 3T3-L1 cells were used as an in vitro model of adipogenesis and lipolysis, using a mixture of insulin/dexamethasone/3-isobutyl-1-methylxanthine (IBMX) to induce differentiation. The amount of lipid droplet accumulation was determined by an AdipoRed assay. The expression of several adipogenic transcription factors and enzymes was investigated using real-time reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting. 18{beta}-GA dose-dependently (1-40 {mu}M) significantly decreased lipid accumulation in maturing preadipocytes. In 3T3-L1 preadipocytes, 10 {mu}M of 18{beta}-GA down-regulated the transcriptional levels of the peroxisome proliferator-activated receptor {gamma}, CCAAT/enhancer-binding protein {alpha} and adiponectin, which are markers of adipogenic differentiation via Akt phosphorylation. Also, in differentiated adipocytes, 18{beta}-GA increased the level of glycerol release and up-regulated the mRNA of hormone-sensitive lipase, adipose TG lipase and perilipin, as well as the phosphorylation of hormone-sensitive lipase at Serine 563. The results indicate that 18{beta

  12. Ursolic Acid Inhibits Adipogenesis in 3T3-L1 Adipocytes through LKB1/AMPK Pathway

    PubMed Central

    He, Yonghan; Li, Ying; Zhao, Tiantian; Wang, Yanwen; Sun, Changhao

    2013-01-01

    Background Ursolic acid (UA) is a triterpenoid compound with multiple biological functions. This compound has recently been reported to possess an anti-obesity effect; however, the mechanisms are less understood. Objective As adipogenesis plays a critical role in obesity, the present study was conducted to investigate the effect of UA on adipogenesis and mechanisms of action in 3T3-L1 preadipocytes. Methods and Results The 3T3-L1 preadipocytes were induced to differentiate in the presence or absence of UA for 6 days. The cells were determined for proliferation, differentiation, fat accumulation as well as the protein expressions of molecular targets that regulate or are involved in fatty acid synthesis and oxidation. The results demonstrated that ursolic acid at concentrations ranging from 2.5 µM to 10 µM dose-dependently attenuated adipogenesis, accompanied by reduced protein expression of CCAAT element binding protein β (C/EBPβ), peroxisome proliferator-activated receptor γ (PPARγ), CCAAT element binding protein α (C/EBPα) and sterol regulatory element binding protein 1c (SREBP-1c), respectively. Ursolic acid increased the phosphorylation of acetyl-CoA carboxylase (ACC) and protein expression of carnitine palmitoyltransferase 1 (CPT1), but decreased protein expression of fatty acid synthase (FAS) and fatty acid-binding protein 4 (FABP4). Ursolic acid increased the phosphorylation of AMP-activated protein kinase (AMPK) and protein expression of (silent mating type information regulation 2, homolog) 1 (Sirt1). Further studies demonstrated that the anti-adipogenic effect of UA was reversed by the AMPK siRNA, but not by the Sirt1 inhibitor nicotinamide. Liver kinase B1 (LKB1), the upstream kinase of AMPK, was upregulated by UA. When LKB1 was silenced with siRNA or the inhibitor radicicol, the effect of UA on AMPK activation was diminished. Conclusions Ursolic acid inhibited 3T3-L1 preadipocyte differentiation and adipogenesis through the LKB1/AMPK pathway

  13. Significance of CO2 donor on the production of succinic acid by Actinobacillus succinogenes ATCC 55618

    PubMed Central

    2011-01-01

    Background Succinic acid is a building-block chemical which could be used as the precursor of many industrial products. The dissolved CO2 concentration in the fermentation broth could strongly regulate the metabolic flux of carbon and the activity of phosphoenolpyruvate (PEP) carboxykinase, which are the important committed steps for the biosynthesis of succinic acid by Actinobacillus succinogenes. Previous reports showed that succinic acid production could be promoted by regulating the supply of CO2 donor in the fermentation broth. Therefore, the effects of dissolved CO2 concentration and MgCO3 on the fermentation process should be investigated. In this article, we studied the impacts of gaseous CO2 partial pressure, dissolved CO2 concentration, and the addition amount of MgCO3 on succinic acid production by Actinobacillus succinogenes ATCC 55618. We also demonstrated that gaseous CO2 could be removed when MgCO3 was fully supplied. Results An effective CO2 quantitative mathematical model was developed to calculate the dissolved CO2 concentration in the fermentation broth. The highest succinic acid production of 61.92 g/L was obtained at 159.22 mM dissolved CO2 concentration, which was supplied by 40 g/L MgCO3 at the CO2 partial pressure of 101.33 kPa. When MgCO3 was used as the only CO2 donor, a maximal succinic acid production of 56.1 g/L was obtained, which was just decreased by 7.03% compared with that obtained under the supply of gaseous CO2 and MgCO3. Conclusions Besides the high dissolved CO2 concentration, the excessive addition of MgCO3 was beneficial to promote the succinic acid synthesis. This was the first report investigating the replaceable of gaseous CO2 in the fermentation of succinic acid. The results obtained in this study may be useful for reducing the cost of succinic acid fermentation process. PMID:22040346

  14. Mycosporine-like amino acids (MAAs): chemical structure, biosynthesis and significance as UV-absorbing/screening compounds.

    PubMed

    Singh, Shailendra P; Kumari, Sunita; Rastogi, Rajesh P; Singh, Kanchan L; Sinha, Rajeshwar P

    2008-01-01

    Continuous depletion of the stratospheric ozone layer has resulted in an increase in ultraviolet-B (UV-B; 280-315 nm) radiation on the earth's surface which inhibits photochemical and photobiological processes. However, certain photosynthetic organisms have evolved mechanisms to counteract the toxicity of ultraviolet or high photosynthetically active radiation by synthesizing the UV-absorbing/screening compounds, such as mycosporine-like amino acids (MAAs) and scytonemin besides the repair of UV-induced damage of DNA and accumulation of carotenoids and detoxifying enzymes or radical quenchers and antioxidants. Chemical structure of various MAAs, their possible biochemical routes of synthesis and role as photoprotective compounds in various organisms are discussed.

  15. Boron Stress Activates the General Amino Acid Control Mechanism and Inhibits Protein Synthesis

    PubMed Central

    Uluisik, Irem; Kaya, Alaattin; Fomenko, Dmitri E.; Karakaya, Huseyin C.; Carlson, Bradley A.; Gladyshev, Vadim N.; Koc, Ahmet

    2011-01-01

    Boron is an essential micronutrient for plants, and it is beneficial for animals. However, at high concentrations boron is toxic to cells although the mechanism of this toxicity is not known. Atr1 has recently been identified as a boron efflux pump whose expression is upregulated in response to boron treatment. Here, we found that the expression of ATR1 is associated with expression of genes involved in amino acid biosynthesis. These mechanisms are strictly controlled by the transcription factor Gcn4 in response to boron treatment. Further analyses have shown that boron impaired protein synthesis by promoting phosphorylation of eIF2α in a Gcn2 kinase dependent manner. The uncharged tRNA binding domain (HisRS) of Gcn2 is necessary for the phosphorylation of eIF2α in the presence of boron. We postulate that boron exerts its toxic effect through activation of the general amino acid control system and inhibition of protein synthesis. Since the general amino acid control pathway is conserved among eukaryotes, this mechanism of boron toxicity may be of general importance. PMID:22114689

  16. Evaluation of the inhibitive effect of benzotriazole on archeological bronze in acidic medium

    NASA Astrophysics Data System (ADS)

    Hassairi, Hèla; Bousselmi, Latifa; Khosrof, Slim; Triki, Ezzeddine

    2013-12-01

    An archaeological bronze artefact was a Punic coin excavated from the north east of Tunisia in 2001. The composition of the copper alloy revealed a content of 3.5 % of tin and 1.4 % of lead with the presence of some sulphur heterogeneity. The surface presents some roughnesses and cracks and is covered by a corrosion layer of 20-40 μm thickness. The use of benzotriazole (BTA) as an inhibitor has become a standard element for the preservation of cuprous-based metals. In order to investigate the behaviour of BTA in an acidic medium, an Electrochemical Impedance Spectroscopy (EIS) investigation was performed to characterize the electrochemical behaviour of the interface of the archaeological bronze sample/acidic medium without and with BTA addition. Impedance diagrams obtained at different immersion times show that the presence of the inhibitor prevents the diffusional process observed in the absence of BTA. The inhibition of the pre-polarized bronze surface revealed that the mechanism of action of the benzotriazole molecule in an acidic medium is governed by the chemisorption process.

  17. Hydrogen assisted cracking and inhibition of spring alloys in acidizing solutions

    SciTech Connect

    Coyle, W.R.; Chitwood, G.B.; Rice, P.W.; Walker, M.L.

    1994-12-31

    Several experiments were conducted to investigate and compare the hydrogen assisted cracking resistance of high strength, corrosion resistant spring alloys to acidizing fluids. Two cobalt-based alloys, UNS R30035 and UNS R30003, and one nickel-based alloy, UNS N07750, were evaluated. The tests involved exposing stressed spring segments of all alloys and C-rings of R30035 to uninhibited 28% HCl, 28% HCl with two different inhibitors, and the NACE TM0177 solution. Failures of N07750 spring segments in the uninhibited acid parallel field performance of this alloy. There were no failures of the R30035 or R30003 spring segments in the environments tested. Springs made from N07750 are more susceptible to hydrogen embrittlement than either R30035 or R30003. The C-ring tests of R30035 revealed the benefit of corrosion inhibition as a means of elevating the threshold cracking stress and increasing the time to failure in corrosive media. A strong beneficial effect of elevated-temperature thermal processing was observed for UNS R30035. High performance acidizing inhibitors are required in order to provide effective protection to high alloy spring materials.

  18. Isolation, characterization, and systematic significance of 2-pyrone-4,6-dicarboxylic acid in Rosaceae.

    PubMed

    Wilkes, S; Glasl, H

    2001-10-01

    2-Pyrone-4,6-dicarboxylic acid was isolated from Potentilla anserina. Until now this substance was only found in bacteria and not in higher plants. By sterile cultivation it was verified that this compound is genuine also in plants. In addition the systematic relevance of 2-pyrone-4,6-dicarboxylic acid within the Rosaceae was tested. The compound seems to be a chemotaxonomic marker for the Rosoideae sensu stricto proposed by Morgan et al. (Morgan, D.R., Soltis, D.E., Robertson, K.R., 1994. Systematic and evolutionary implications of rbcL sequence variation in Rosaceae. American Journal of Botany 81, 890-903).

  19. Calcite growth-rate inhibition by fulvic acids isolated from Big Soda Lake, Nevada, USA, The Suwannee River, Georgia, USA and by polycarboxylic acids

    USGS Publications Warehouse

    Reddy, Michael M.; Leenheer, Jerry

    2011-01-01

    Calcite crystallization rates are characterized using a constant solution composition at 25°C, pH=8.5, and calcite supersaturation (Ω) of 4.5 in the absence and presence of fulvic acids isolated from Big Soda Lake, Nevada (BSLFA), and a fulvic acid from the Suwannee River, Georgia (SRFA). Rates are also measured in the presence and absence of low-molar mass, aliphatic-alicyclic polycarboxylic acids (PCA). BSLFA inhibits calcite crystal-growth rates with increasing BSLFA concentration, suggesting that BSLFA adsorbs at growth sites on the calcite crystal surface. Calcite growth morphology in the presence of BSLFA differed from growth in its absence, supporting an adsorption mechanism of calcite-growth inhibition by BSLFA. Calcite growth-rate inhibition by BSLFA is consistent with a model indicating that polycarboxylic acid molecules present in BSLFA adsorb at growth sites on the calcite crystal surface. In contrast to published results for an unfractionated SRFA, there is dramatic calcite growth inhibition (at a concentration of 1 mg/L) by a SRFA fraction eluted by pH 5 solution from XAD-8 resin, indicating that calcite growth-rate inhibition is related to specific SRFA component fractions. A cyclic PCA, 1, 2, 3, 4, 5, 6-cyclohexane hexacarboxylic acid (CHXHCA) is a strong calcite growth-rate inhibitor at concentrations less than 0.1 mg/L. Two other cyclic PCAs, 1, 1 cyclopentanedicarboxylic acid (CPDCA) and 1, 1 cyclobutanedicarboxylic acid (CBDCA) with the carboxylic acid groups attached to the same ring carbon atom, have no effect on calcite growth rates up to concentrations of 10 mg/L. Organic matter ad-sorbed from the air onto the seed crystals has no effect on the measured calcite crystal-growth rates.

  20. Ursolic acid sensitized colon cancer cells to chemotherapy under hypoxia by inhibiting MDR1 through HIF-1α*

    PubMed Central

    Shan, Jian-zhen; Xuan, Yan-yan; Zhang, Qi; Huang, Jian-jin

    2016-01-01

    Objective: To explore the efficacy of ursolic acid in sensitizing colon cancer cells to chemotherapy under hypoxia and its underlying mechanisms. Methods: Three colon cancer cell lines (RKO, LoVo, and SW480) were used as in vitro models. 5-Fluorouracil (5-FU) and oxaliplatin were used as chemotherapeutic drugs. Cell viability and apoptosis were tested to evaluate the sensitivity of colon cancer cells to chemotherapy. The transcription and expression levels of hypoxia-inducible factor-1α (HIF-1α), multidrug resistance gene 1 (MDR1), and vascular endothelial growth factors (VEGF) were assessed by quantitative real-time polymerase chain reaction (qRT-PCR) and immunoblotting. Cycloheximide and MG132 were used to inhibit protein synthesis and degradation, respectively. In vitro tube formation assay was used to evaluate angiogenesis. Results: We demonstrated the chemosensitizing effects of ursolic acid with 5-FU and oxaliplatin in three colon cancer cell lines under hypoxia. This effect was correlated to its inhibition of MDR1 through HIF-1α. Moreover, ursolic acid was capable of inhibiting HIF-1α accumulation with little effects on its constitutional expression in normoxia. In addition, ursolic acid also down-regulated VEGF and inhibited tumor angiogenesis. Conclusions: Ursolic acid exerted chemosensitizing effects in colon cancer cells under hypoxia by inhibiting HIF-1α accumulation and the subsequent expression of the MDR1 and VEGF. PMID:27604859

  1. Oxymetazoline inhibits proinflammatory reactions: effect on arachidonic acid-derived metabolites.

    PubMed

    Beck-Speier, Ingrid; Dayal, Niru; Karg, Erwin; Maier, Konrad L; Schumann, Gabriele; Semmler, Manuela; Koelsch, Stephan M

    2006-02-01

    The nasal decongestant oxymetazoline effectively reduces rhinitis symptoms. We hypothesized that oxymetazoline affects arachidonic acid-derived metabolites concerning inflammatory and oxidative stress-dependent reactions. The ability of oxymetazoline to model pro- and anti-inflammatory and oxidative stress responses was evaluated in cell-free systems, including 5-lipoxygenase (5-LO) as proinflammatory, 15-lipoxygenase (15-LO) as anti-inflammatory enzymes, and oxidation of methionine by agglomerates of ultrafine carbon particles (UCPs), indicating oxidative stress. In a cellular approach using canine alveolar macrophages (AMs), the impact of oxymetazoline on phospholipase A(2) (PLA(2)) activity, respiratory burst and synthesis of prostaglandin E(2) (PGE(2)), 15(S)-hydroxy-eicosatetraenoic acid (15-HETE), leukotriene B(4) (LTB(4)), and 8-isoprostane was measured in the absence and presence of UCP or opsonized zymosan as particulate stimulants. In cell-free systems, oxymetazoline (0.4-1 mM) inhibited 5-LO but not 15-LO activity and did not alter UCP-induced oxidation of methionine. In AMs, oxymetazoline induced PLA(2) activity and 15-HETE at 1 mM, enhanced PGE(2) at 0.1 mM, strongly inhibited LTB(4) and respiratory burst at 0.4/0.1 mM (p < 0.05), but did not affect 8-isoprostane formation. In contrast, oxymetazoline did not alter UCP-induced PLA(2) activity and PGE(2) and 15-HETE formation in AMs but inhibited UCP-induced LTB(4) formation and respiratory burst at 0.1 mM and 8-isoprostane formation at 0.001 mM (p < 0.05). In opsonized zymosan-stimulated AMs, oxymetazoline inhibited LTB(4) formation and respiratory burst at 0.1 mM (p < 0.05). In conclusion, in canine AMs, oxymetazoline suppressed proinflammatory reactions including 5-LO activity, LTB(4) formation, and respiratory burst and prevented particle-induced oxidative stress, whereas PLA(2) activity and synthesis of immune-modulating PGE(2) and 15-HETE were not affected.

  2. Effect of molecular structure of aniline-formaldehyde copolymers on corrosion inhibition of mild steel in hydrochloric acid solution.

    PubMed

    Zhang, Yan; Nie, Mengyan; Wang, Xiutong; Zhu, Yukun; Shi, Fuhua; Yu, Jianqiang; Hou, Baorong

    2015-05-30

    Aniline-formaldehyde copolymers with different molecular structures have been prepared and investigated for the purpose of corrosion control of mild steel in hydrochloric acid. The copolymers were synthesized by a condensation polymerization process with different ratios of aniline to formaldehyde in acidic precursor solutions. The corrosion inhibition efficiency of as-synthesized copolymers for Q235 mild steel was investigated in 1.0 mol L(-1) hydrochloric acid solution by weight loss measurement, potentiodynamic polarization, and electrochemical impedance spectroscopy, respectively. All the results demonstrate that as-prepared aniline-formaldehyde copolymers are efficient mixed-type corrosion inhibitors for mild steels in hydrochloric acid. The corrosion inhibition mechanism is discussed in terms of the role of molecular structure on adsorption of the copolymers onto the steel surface in acid solution.

  3. Exogenous abscisic acid significantly affects proteome in tea plant (Camellia sinensis) exposed to drought stress

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tea [Camellia sinensis (L.) O. Kuntze] is an important economic crop, and drought is the most important abiotic stress affecting yield and quality. Abscisic acid (ABA) is an important phytohormone responsible for activating drought resistance. Increased understanding of ABA effects on tea plant unde...

  4. The significance of linoleic acid in food sources for detritivorous benthic invertebrates

    PubMed Central

    Vonk, J. Arie; van Kuijk, Bernd F.; van Beusekom, Mick; Hunting, Ellard R.; Kraak, Michiel H. S.

    2016-01-01

    Chemical composition of organic matter (OM) is a key driver for detritus consumption by macroinvertebrates and polyunsaturated fatty acid (PUFA) content is considered a candidate indicator of food palatability. Since traditionally used complex natural OM covaries in many quality attributes, it remains uncertain whether benthic invertebrates developed an actual preference for PUFA-rich food. Therefore we aimed to test the influence of the PUFA linoleic acid on OM consumption by aquatic macroinvertebrates using standardized surrogate substrates (decomposition and consumption tablet, DECOTAB) with added linoleic acid (PUFA) in comparison to consumption of DECOTAB containing only cellulose (Standard) or ground macrophytes (Plant). In microcosms, we observed a higher consumption rate of PUFA DECOTAB in comparison to Standard DECOTAB in two functionally distinct invertebrate species (Lumbriculus variegatus and Asellus aquaticus). This effect appeared to be overruled in the field due to unknown sources of natural variation. Although we observed higher consumption rates in species-rich ditches compared to species-poor ditches, consumption rates were comparable for all three types of DECOTAB deployed. Upon reduced food quality and palatability, results presented here hint that PUFA like linoleic acid may be a key OM attribute driving the performance of benthic macroinvertebrates and inherent functioning of aquatic ecosystems. PMID:27767068

  5. Methods for evaluating the biological significance of acidic episodes in streams

    SciTech Connect

    Christensen, S.W.; Sale, M.J.; Beauchamp, J.J.

    1987-01-01

    During storms or periods of snowmelt, the levels of acidity and aluminum in streams can increase greatly. An approach is presented for designing and analyzing laboratory experiments that investigate the relationship between episodic changes in water chemistry and survival of fish. (ACR)

  6. Eicosapentaenoic acid inhibits TNF-{alpha}-induced matrix metalloproteinase-9 expression in human keratinocytes, HaCaT cells

    SciTech Connect

    Kim, Hyeon Ho; Lee, Youngae; Eun, Hee Chul Chung, Jin Ho

    2008-04-04

    Eicosapentaenoic acid (EPA) is an omega-3 ({omega}-3) polyunsaturated fatty acid (PUFA), which has anti-inflammatory and anti-cancer properties. Some reports have demonstrated that EPA inhibits NF-{kappa}B activation induced by tumor necrosis factor (TNF)-{alpha} or lipopolysaccharide (LPS) in various cells. However, its detailed mode of action is unclear. In this report, we investigated whether EPA inhibits the expression of TNF-{alpha}-induced matrix metalloproteinases (MMP)-9 in human immortalized keratinocytes (HaCaT). TNF-{alpha} induced MMP-9 expression by NF-{kappa}B-dependent pathway. Pretreatment of EPA inhibited TNF-{alpha}-induced MMP-9 expression and p65 phosphorylation. However, EPA could not affect I{kappa}B-{alpha} phosphorylation, nuclear translocation of p65, and DNA binding activity of NF-{kappa}B. EPA inhibited TNF-{alpha}-induced p65 phosphorylation through p38 and Akt inhibition and this inhibition was IKK{alpha}-dependent event. Taken together, we demonstrate that EPA inhibits TNF-{alpha}-induced MMP-9 expression through inhibition of p38 and Akt activation.

  7. The Significance of Acid Alteration in the Los Humeros High-Temperature Geothermal Field, Puebla, Mexico.

    NASA Astrophysics Data System (ADS)

    Elders, W. A.; Izquierdo, G.

    2014-12-01

    The Los Humeros geothermal field is a high-enthalpy hydrothermal system with more than 40 drilled deep wells, mostly producing high steam fractions at > 300oC. However, although it has a large resource potential, low permeability and corrosive acid fluids have hampered development so that it currently has an installed electrical generating capacity of only 40 MWe. The widespread production of low pH fluids from the reservoir is inconsistent with the marked absence in the reservoir rocks of hydrothermal minerals typical of acid alteration. Instead the hydrothermal alteration observed is typical of that due to neutral to alkaline pH waters reacting with the volcanic rocks of the production zones. Thus it appears that since the reservoir has recently suffered a marked drop in fluid pressure and is in process of transitioning from being water-dominated to being vapor-dominated. However sparse examples of acid leaching are observed locally at depths of about 2 km in the form of bleached, intensely silicified zones, in low permeability and very hot (>350oC) parts of reservoir. Although these leached rocks retain their primary volcanic and pyroclastic textures, they are altered almost entirely to microcrystalline quartz, with some relict pseudomorphs of plagioclase phenocrysts and traces of earlier-formed hydrothermal chlorite and pyrite. These acid-altered zones are usually only some tens of meters thick and deeper rocks lack such silicification. The acid fluids responsible for their formation could either be magmatic volatiles, or could be formed during production (e.g. reaction of water and salts forming hydrogen chloride by hydrolysis at high temperatures). The very high boron content of the fluids produced by the Los Humeros wells suggests that their ultimate source is most likely magmatic gases. However, these acid gases did not react widely with the rocks. We suggest that the silicified zones are forming locally where colder descending waters are encountering

  8. Conformationally-restricted amino acid analogues bearing a distal sulfonic acid show selective inhibition of system x(c)(-) over the vesicular glutamate transporter.

    PubMed

    Etoga, Jean-Louis G; Ahmed, S Kaleem; Patel, Sarjubhai; Bridges, Richard J; Thompson, Charles M

    2010-04-15

    A panel of amino acid analogs and conformationally-restricted amino acids bearing a sulfonic acid were synthesized and tested for their ability to preferentially inhibit the obligate cysteine-glutamate transporter system x(c)(-) versus the vesicular glutamate transporter (VGLUT). Several promising candidate molecules were identified: R/S-4-[4'-carboxyphenyl]-phenylglycine, a biphenyl substituted analog of 4-carboxyphenylglycine and 2-thiopheneglycine-5-sulfonic acid both of which reduced glutamate uptake at system x(c)(-) by 70-75% while having modest to no effect on glutamate uptake at VGLUT.

  9. Precursor Amino Acids Inhibit Polymyxin E Biosynthesis in Paenibacillus polymyxa, Probably by Affecting the Expression of Polymyxin E Biosynthesis-Associated Genes

    PubMed Central

    Guo, Chenglin; Qiu, Juanping

    2015-01-01

    Polymyxin E belongs to cationic polypeptide antibiotic bearing four types of direct precursor amino acids including L-2,4-diaminobutyric acid (L-Dab), L-Leu, D-Leu, and L-Thr. The objective of this study is to evaluate the effect of addition of precursor amino acids during fermentation on polymyxin E biosynthesis in Paenibacillus polymyxa. The results showed that, after 35 h fermentation, addition of direct precursor amino acids to certain concentration significantly inhibited polymyxin E production and affected the expression of genes involved in its biosynthesis. L-Dab repressed the expression of polymyxin synthetase genes pmxA and pmxE, as well as 2,4-diaminobutyrate aminotransferase gene ectB; both L-Leu and D-Leu repressed the pmxA expression. In addition, L-Thr affected the expression of not only pmxA, but also regulatory genes spo0A and abrB. As L-Dab precursor, L-Asp repressed the expression of ectB, pmxA, and pmxE. Moreover, it affected the expression of spo0A and abrB. In contrast, L-Phe, a nonprecursor amino acid, had no obvious effect on polymyxin E biosynthesis and those biosynthesis-related genes expression. Taken together, our data demonstrated that addition of precursor amino acids during fermentation will inhibit polymyxin E production probably by affecting the expression of its biosynthesis-related genes. PMID:26078961

  10. Combination of 13 cis-retinoic acid and tolfenamic acid induces apoptosis and effectively inhibits high-risk neuroblastoma cell proliferation.

    PubMed

    Shelake, Sagar; Eslin, Don; Sutphin, Robert M; Sankpal, Umesh T; Wadwani, Anmol; Kenyon, Laura E; Tabor-Simecka, Leslie; Bowman, W Paul; Vishwanatha, Jamboor K; Basha, Riyaz

    2015-11-01

    Chemotherapeutic regimens used for the treatment of Neuroblastoma (NB) cause long-term side effects in pediatric patients. NB arises in immature sympathetic nerve cells and primarily affects infants and children. A high rate of relapse in high-risk neuroblastoma (HRNB) necessitates the development of alternative strategies for effective treatment. This study investigated the efficacy of a small molecule, tolfenamic acid (TA), for enhancing the anti-proliferative effect of 13 cis-retinoic acid (RA) in HRNB cell lines. LA1-55n and SH-SY5Y cells were treated with TA (30μM) or RA (20μM) or both (optimized doses, derived from dose curves) for 48h and tested the effect on cell viability, apoptosis and selected molecular markers (Sp1, survivin, AKT and ERK1/2). Cell viability and caspase activity were measured using the CellTiter-Glo and Caspase-Glo kits. The apoptotic cell population was determined by flow cytometry with Annexin-V staining. The expression of Sp1, survivin, AKT, ERK1/2 and c-PARP was evaluated by Western blots. The combination therapy of TA and RA resulted in significant inhibition of cell viability (p<0.0001) when compared to individual agents. The anti-proliferative effect is accompanied by a decrease in Sp1 and survivin expression and an increase in apoptotic markers, Annexin-V positive cells, caspase 3/7 activity and c-PARP levels. Notably, TA+RA combination also caused down regulation of AKT and ERK1/2 suggesting a distinct impact on survival and proliferation pathways via signaling cascades. This study demonstrates that the TA mediated inhibition of Sp1 in combination with RA provides a novel therapeutic strategy for the effective treatment of HRNB in children.