Forgot your password?
New user?
New Window Opens on the Secret Life of Microbes: Scientists Develop First Microbial Profiles of Ecosystems
CAS announces the release of SciFinder Scholar for Mac OS X
Press Releases
Press Releases
| Check out our New Publishers' Select for Free Articles |
Biochemical Pharmacology (v.74, #7)
Phospholipase A2 as targets for anti-cancer drugs by Brian S. Cummings (pp. 949-959).
Phospholipase A2 (PLA2) are esterases that cleave glycerophospholipids to release fatty acids and lysophospholipids. Inhibition of PLA2 alters cancer cell growth and death in vitro and PLA2 expression is increased in breast, lung, and prostate cancers compared to control tissues. Thus, PLA2 may be novel targets for chemotherapeutics. However, PLA2 are a diverse family of enzymes, encompassing 19 members. The selectivity of these individual PLA2 for phospholipids varies, as does their location within the cell, and tissue expression. Thus, their role in cancer may also vary. This review summarizes the expression of individual PLA2 in cancers, focuses on the potential mechanisms by which these esterases mediate carcinogenesis, and suggests that select PLA2 isoforms may be targets for anti-cancer drugs.
Keywords: Abbreviations; BEL; bromoenol lactone; COX; cyclooxygenase; cPLA; 2; cytosolic phospholipase A; 2; CYPP450; cytochrome P450 monooxygneaes; EET; epoxyeicosatrienoic acid; HETE; hydroxyeicosatetraenoic acid; HPETE; hydroperoxyeicosatetraenoic acid; iPLA; 2; Ca; 2+; -independent phospholipase A; 2; LOX; lipoxygenase; LTC; 4; leukotrienes; LysoPLD; lysophospholipid specific phospholipase D; NSAID; nonsteroidal anti-inflammatory drugs; PAF; platelet activating factor; PAF-HA; platelet activating factor-acetylhydrolase; PGE; 2; prostaglandins; PGI; 2; prostacyclins; PLA; 2; phospholipase A; 2; PPAR; peroxisomal proliferator activated receptor; sPLA; 2; secretory phospholipase A; 2; TXA; 2; thromboxanesPhospholipase A; 2; Carcinogenesis; Arachidonic acid; Lysophosphatidic acid; Tumor formation; Cell growth
Phospholipase A2 as targets for anti-cancer drugs by Brian S. Cummings (pp. 949-959).
Phospholipase A2 (PLA2) are esterases that cleave glycerophospholipids to release fatty acids and lysophospholipids. Inhibition of PLA2 alters cancer cell growth and death in vitro and PLA2 expression is increased in breast, lung, and prostate cancers compared to control tissues. Thus, PLA2 may be novel targets for chemotherapeutics. However, PLA2 are a diverse family of enzymes, encompassing 19 members. The selectivity of these individual PLA2 for phospholipids varies, as does their location within the cell, and tissue expression. Thus, their role in cancer may also vary. This review summarizes the expression of individual PLA2 in cancers, focuses on the potential mechanisms by which these esterases mediate carcinogenesis, and suggests that select PLA2 isoforms may be targets for anti-cancer drugs.
Keywords: Abbreviations; BEL; bromoenol lactone; COX; cyclooxygenase; cPLA; 2; cytosolic phospholipase A; 2; CYPP450; cytochrome P450 monooxygneaes; EET; epoxyeicosatrienoic acid; HETE; hydroxyeicosatetraenoic acid; HPETE; hydroperoxyeicosatetraenoic acid; iPLA; 2; Ca; 2+; -independent phospholipase A; 2; LOX; lipoxygenase; LTC; 4; leukotrienes; LysoPLD; lysophospholipid specific phospholipase D; NSAID; nonsteroidal anti-inflammatory drugs; PAF; platelet activating factor; PAF-HA; platelet activating factor-acetylhydrolase; PGE; 2; prostaglandins; PGI; 2; prostacyclins; PLA; 2; phospholipase A; 2; PPAR; peroxisomal proliferator activated receptor; sPLA; 2; secretory phospholipase A; 2; TXA; 2; thromboxanesPhospholipase A; 2; Carcinogenesis; Arachidonic acid; Lysophosphatidic acid; Tumor formation; Cell growth
Rosmarinic acid induces melanogenesis through protein kinase A activation signaling by Jongsung Lee; Yeong Shik Kim; Deokhoon Park (pp. 960-968).
Melanogenesis is a physiological process that results in the synthesis of melanin pigments, which play a crucial protective role against skin photocarcinogenesis. In order to determine the effects of rosmarinic acid on melanogenesis and elucidate the molecular events of melanogenesis induced by rosmarinic acid, several experiments were performed in B16 melanoma cells. In this study, we showed that the melanin content and tyrosinase expression were increased by rosmarinic acid in a concentration-dependent manner. In addition, after the melanin content was increased by rosmarinic acid, it was reduced by H-89 and KT 5720, protein kinase A (PKA) inhibitors, but not by SB203580, a p38mapk inhibitor, or Ro-32-0432, a PKC inhibitor, which suggests the involvement of PKA in rosmarinic acid-induced melanogenesis. Consistent with this, rosmarinic acid induced the phosphorylation of CRE-binding protein (CREB), but had no effect on the phosphorylation of p38mapk or the inhibition of Akt phosphorylation. Additionally, rosmarinic acid induced the activation of cAMP response element (CRE) without having any effect on cAMP production, which suggests that rosmarinic acid-induced melanogenesis is mediated by PKA, which occurs downstream of cAMP production. This result was further confirmed by the fact that rosmarinic acid-induced phosphorylation of CREB was inhibited by H-89, but not by PD98059, a MEK1 inhibitor, or by LY294002, a phosphatidylinositol-3-kinase (PI3K) inhibitor. Rosmarinic acid-induced expression of tyrosinase protein was attenuated by H-89. Based on these results, we report for the first time that rosmarinic acid induces melanogenesis through PKA activation signaling.
Keywords: Abbreviations; PKA; protein kinase A; CREB; CRE binding protein; GSK 3β; glycogen synthase kinase 3β; MITF; microphthalmia-associated transcription factorRosmarinic acid; Protein kinase A; CRE; Melanogenesis; Tyrosinase
Rosmarinic acid induces melanogenesis through protein kinase A activation signaling by Jongsung Lee; Yeong Shik Kim; Deokhoon Park (pp. 960-968).
Melanogenesis is a physiological process that results in the synthesis of melanin pigments, which play a crucial protective role against skin photocarcinogenesis. In order to determine the effects of rosmarinic acid on melanogenesis and elucidate the molecular events of melanogenesis induced by rosmarinic acid, several experiments were performed in B16 melanoma cells. In this study, we showed that the melanin content and tyrosinase expression were increased by rosmarinic acid in a concentration-dependent manner. In addition, after the melanin content was increased by rosmarinic acid, it was reduced by H-89 and KT 5720, protein kinase A (PKA) inhibitors, but not by SB203580, a p38mapk inhibitor, or Ro-32-0432, a PKC inhibitor, which suggests the involvement of PKA in rosmarinic acid-induced melanogenesis. Consistent with this, rosmarinic acid induced the phosphorylation of CRE-binding protein (CREB), but had no effect on the phosphorylation of p38mapk or the inhibition of Akt phosphorylation. Additionally, rosmarinic acid induced the activation of cAMP response element (CRE) without having any effect on cAMP production, which suggests that rosmarinic acid-induced melanogenesis is mediated by PKA, which occurs downstream of cAMP production. This result was further confirmed by the fact that rosmarinic acid-induced phosphorylation of CREB was inhibited by H-89, but not by PD98059, a MEK1 inhibitor, or by LY294002, a phosphatidylinositol-3-kinase (PI3K) inhibitor. Rosmarinic acid-induced expression of tyrosinase protein was attenuated by H-89. Based on these results, we report for the first time that rosmarinic acid induces melanogenesis through PKA activation signaling.
Keywords: Abbreviations; PKA; protein kinase A; CREB; CRE binding protein; GSK 3β; glycogen synthase kinase 3β; MITF; microphthalmia-associated transcription factorRosmarinic acid; Protein kinase A; CRE; Melanogenesis; Tyrosinase
Protection by doxycycline against doxorubicin-induced oxidative stress and apoptosis in mouse testes by Yueh-Chiao Yeh; Hui-Chin Lai; Chih-Tai Ting; Wen-Lieng Lee; Li-Chuan Wang; Kuo-Yang Wang; Hui-Chun Lai; Tsun-Jui Liu (pp. 969-980).
Spermatogenic cells constitute one of the body tissues that are susceptible to doxorubicin-induced oxidative stress and apoptosis. To explore whether doxorubicin toxicity to these male germ cells could be prevented by adjuvant medication, this study was designed to examine the possible ameliorating action of doxycycline, an antibiotic with anti-oxidant property, on doxorubicin-induced oxidative and apoptotic effects in mouse testes. Male mice at 5-week of age were treated with vehicles, doxorubicin alone (3mg/kg, i.p. every other day for 3 doses), doxycycline alone (2.5mg/kg, i.p. every other day for 3 doses), or doxycycline plus doxorubicin (each dose given 1 day post-doxycycline). After 28 days, mice treated with doxorubicin alone displayed smaller body and testicular weights, reduced sperm counts, impaired spermatogenic capability (scarcer spermatids and spermatocytes), increased oxidative stress (malondialdehyde levels), decreased anti-oxidant activity (superoxide dismutase and glutathione peroxidase), and elevated apoptotic indexes (upregulation of Bax and Bad, downregulation of Bcl-2 and Bcl-xL, release of cytochrome c from mitochondria to cytosol, activation of caspase-3, and increase of cleaved caspase-3 abundance and TUNEL positive cells), while doxycycline pretreatment could effectively prevent nearly all of these abnormalities. These results provide firm evidence that doxycycline pretreatment would offset the oxidative and apoptotic impact imposed by doxorubicin, and imply doxycycline to be a promising adjuvant agent that may attenuate the toxicity of doxorubicin on testicular tissues in clinical practice.
Keywords: Abbreviations; Dox; doxorubicin; Dc; doxycycline; DTT; dl; -dithiothreitol; DAPI; 4′,6′ diamidino-2-phynylindole; TUNEL; terminal deoxynucleotidyl transferase-mediated dUTP nick end-labelingDoxycycline; Doxorubicin; Testis; Oxidative stress; Apoptosis
Protection by doxycycline against doxorubicin-induced oxidative stress and apoptosis in mouse testes by Yueh-Chiao Yeh; Hui-Chin Lai; Chih-Tai Ting; Wen-Lieng Lee; Li-Chuan Wang; Kuo-Yang Wang; Hui-Chun Lai; Tsun-Jui Liu (pp. 969-980).
Spermatogenic cells constitute one of the body tissues that are susceptible to doxorubicin-induced oxidative stress and apoptosis. To explore whether doxorubicin toxicity to these male germ cells could be prevented by adjuvant medication, this study was designed to examine the possible ameliorating action of doxycycline, an antibiotic with anti-oxidant property, on doxorubicin-induced oxidative and apoptotic effects in mouse testes. Male mice at 5-week of age were treated with vehicles, doxorubicin alone (3mg/kg, i.p. every other day for 3 doses), doxycycline alone (2.5mg/kg, i.p. every other day for 3 doses), or doxycycline plus doxorubicin (each dose given 1 day post-doxycycline). After 28 days, mice treated with doxorubicin alone displayed smaller body and testicular weights, reduced sperm counts, impaired spermatogenic capability (scarcer spermatids and spermatocytes), increased oxidative stress (malondialdehyde levels), decreased anti-oxidant activity (superoxide dismutase and glutathione peroxidase), and elevated apoptotic indexes (upregulation of Bax and Bad, downregulation of Bcl-2 and Bcl-xL, release of cytochrome c from mitochondria to cytosol, activation of caspase-3, and increase of cleaved caspase-3 abundance and TUNEL positive cells), while doxycycline pretreatment could effectively prevent nearly all of these abnormalities. These results provide firm evidence that doxycycline pretreatment would offset the oxidative and apoptotic impact imposed by doxorubicin, and imply doxycycline to be a promising adjuvant agent that may attenuate the toxicity of doxorubicin on testicular tissues in clinical practice.
Keywords: Abbreviations; Dox; doxorubicin; Dc; doxycycline; DTT; dl; -dithiothreitol; DAPI; 4′,6′ diamidino-2-phynylindole; TUNEL; terminal deoxynucleotidyl transferase-mediated dUTP nick end-labelingDoxycycline; Doxorubicin; Testis; Oxidative stress; Apoptosis
Autophagic cell death, polyploidy and senescence induced in breast tumor cells by the substituted pyrrole JG-03-14, a novel microtubule poison by Christopher R. Arthur; John T. Gupton; Glen E. Kellogg; W. Andrew Yeudall; Myles C. Cabot; Irene F. Newsham; David A. Gewirtz (pp. 981-991).
JG-03-14, a substituted pyrrole that inhibits microtubule polymerization, was screened against MCF-7 (p53 wild type), MDA-MB231 (p53 mutant), MCF-7/caspase 3 and MCF-7/ADR (multidrug resistant) breast tumor cell lines. Cell viability and growth inhibition were assessed by the crystal violet dye assay. Apoptosis was evaluated by the TUNEL assay, cell cycle distribution by flow cytometry, autophagy by acridine orange staining of vesicle formation, and senescence based on β-galactosidase staining and cell morphology. Our studies indicate that exposure to JG-03-14, at a concentration of 500nM, induces time-dependent cell death in the MCF-7 and MDA-MB231 cell lines. In MCF-7 cells, a residual surviving cell population was found to be senescent; in contrast, there was no surviving senescent population in treated MDA-MB231 cells. No proliferative recovery was detected over a period of 15 days post-treatment in either cell line. Both the TUNEL assay and FLOW cytometry indicated a relatively limited degree of apoptosis (<10%) in response to drug treatment in MCF-7 cells with more extensive apoptosis (but <20%) in MDA-MB231 cells; acidic vacuole formation indicative of autophagic cell death was relatively extensive in both MCF-7 and MDA-MB231 cells. In addition, JG-03-14 induced the formation of a large hyperdiploid cell population in MDA-MB231 cells. JG-03-14 also demonstrated pronounced anti-proliferative activity in MCF-7/caspase 3 cells and in the MCF-7/ADR cell line. The observation that JG-03-14 promotes autophagic cell death and also retains activity in tumor cells expressing the multidrug resistance pump indicates that novel microtubule poisons of the substituted pyrroles class may hold promise in the treatment of breast cancer.
Keywords: Substituted pyrrole; Apoptosis; Autophagy; Senescence; Polyploidy; p53; Breast tumor cells; Proliferative recovery
Autophagic cell death, polyploidy and senescence induced in breast tumor cells by the substituted pyrrole JG-03-14, a novel microtubule poison by Christopher R. Arthur; John T. Gupton; Glen E. Kellogg; W. Andrew Yeudall; Myles C. Cabot; Irene F. Newsham; David A. Gewirtz (pp. 981-991).
JG-03-14, a substituted pyrrole that inhibits microtubule polymerization, was screened against MCF-7 (p53 wild type), MDA-MB231 (p53 mutant), MCF-7/caspase 3 and MCF-7/ADR (multidrug resistant) breast tumor cell lines. Cell viability and growth inhibition were assessed by the crystal violet dye assay. Apoptosis was evaluated by the TUNEL assay, cell cycle distribution by flow cytometry, autophagy by acridine orange staining of vesicle formation, and senescence based on β-galactosidase staining and cell morphology. Our studies indicate that exposure to JG-03-14, at a concentration of 500nM, induces time-dependent cell death in the MCF-7 and MDA-MB231 cell lines. In MCF-7 cells, a residual surviving cell population was found to be senescent; in contrast, there was no surviving senescent population in treated MDA-MB231 cells. No proliferative recovery was detected over a period of 15 days post-treatment in either cell line. Both the TUNEL assay and FLOW cytometry indicated a relatively limited degree of apoptosis (<10%) in response to drug treatment in MCF-7 cells with more extensive apoptosis (but <20%) in MDA-MB231 cells; acidic vacuole formation indicative of autophagic cell death was relatively extensive in both MCF-7 and MDA-MB231 cells. In addition, JG-03-14 induced the formation of a large hyperdiploid cell population in MDA-MB231 cells. JG-03-14 also demonstrated pronounced anti-proliferative activity in MCF-7/caspase 3 cells and in the MCF-7/ADR cell line. The observation that JG-03-14 promotes autophagic cell death and also retains activity in tumor cells expressing the multidrug resistance pump indicates that novel microtubule poisons of the substituted pyrroles class may hold promise in the treatment of breast cancer.
Keywords: Substituted pyrrole; Apoptosis; Autophagy; Senescence; Polyploidy; p53; Breast tumor cells; Proliferative recovery
A gold(I) phosphine complex selectively induces apoptosis in breast cancer cells: Implications for anticancer therapeutics targeted to mitochondria by Oliver Rackham; Scott J. Nichols; Peter J. Leedman; Susan J. Berners-Price; Aleksandra Filipovska (pp. 992-1002).
Bis-chelated gold(I) phosphine complexes have shown great potential as anticancer agents, however, their efficacy has been limited by their high toxicity and lack of selectivity for cancer cells. Here, we have investigated the anticancer activity of a new bis-chelated Au(I) bidentate phosphine complex of the novel water soluble ligand 1,3-bis(di-2-pyridylphosphino)propane (d2pypp). We show that this gold complex [Au(d2pypp)2]Cl, at submicromolar concentrations, selectively induces apoptosis in breast cancer cells but not in normal breast cells. Apoptosis was induced via the mitochondrial pathway, which involved mitochondrial membrane potential depolarisation, depletion of the glutathione pool and caspase-3 and caspase-9 activation. The gold lipophilic complex was accumulated in mitochondria of cells, driven by the high mitochondrial membrane potential. To address the molecular basis of the observed selectivity between the two cell lines we investigated the effect of the gold complex on the thioredoxin/thioredoxin reductase system in normal and cancer breast cells. We show that [Au(d2pypp)2]Cl inhibits the activities of both thioredoxin and thioredoxin reductase and that this effect is more pronounced in the breast cancer cells. This difference may account for the selective cell death seen in the breast cancer cells but not in the normal cells. Our investigation has led to new insights into the mechanism of action of bis-chelated gold(I) diphosphine complexes and their future development as mitochondria targeted chemotherapeutics.
Keywords: Abbreviations; Δ; ψ; m; mitochondrial membrane potential; DLC; delocalized lipophilic cation; MPT; membrane permeability transition; Auranofin; 2,3,4,6-tetra-; O; -acetyl-l-thio-β-; d; -glucopyranosato-S-triethylphosphine gold(I); TrxR; thioredoxin reductase; Trx; thioredoxin; [Au(dppe); 2; ]Cl; bis[1,2 bis(diphenylphosphino)ethane]gold(I) chloride; [Au(d2pypp); 2; ]Cl; bis[1,3-bis(di-2-pyridylphosphino)propane]gold(I) chlorideAntitumor agents; Mitochondria; Gold compounds; Apoptosis; Thioredoxin reductase; Thioredoxin
A gold(I) phosphine complex selectively induces apoptosis in breast cancer cells: Implications for anticancer therapeutics targeted to mitochondria by Oliver Rackham; Scott J. Nichols; Peter J. Leedman; Susan J. Berners-Price; Aleksandra Filipovska (pp. 992-1002).
Bis-chelated gold(I) phosphine complexes have shown great potential as anticancer agents, however, their efficacy has been limited by their high toxicity and lack of selectivity for cancer cells. Here, we have investigated the anticancer activity of a new bis-chelated Au(I) bidentate phosphine complex of the novel water soluble ligand 1,3-bis(di-2-pyridylphosphino)propane (d2pypp). We show that this gold complex [Au(d2pypp)2]Cl, at submicromolar concentrations, selectively induces apoptosis in breast cancer cells but not in normal breast cells. Apoptosis was induced via the mitochondrial pathway, which involved mitochondrial membrane potential depolarisation, depletion of the glutathione pool and caspase-3 and caspase-9 activation. The gold lipophilic complex was accumulated in mitochondria of cells, driven by the high mitochondrial membrane potential. To address the molecular basis of the observed selectivity between the two cell lines we investigated the effect of the gold complex on the thioredoxin/thioredoxin reductase system in normal and cancer breast cells. We show that [Au(d2pypp)2]Cl inhibits the activities of both thioredoxin and thioredoxin reductase and that this effect is more pronounced in the breast cancer cells. This difference may account for the selective cell death seen in the breast cancer cells but not in the normal cells. Our investigation has led to new insights into the mechanism of action of bis-chelated gold(I) diphosphine complexes and their future development as mitochondria targeted chemotherapeutics.
Keywords: Abbreviations; Δ; ψ; m; mitochondrial membrane potential; DLC; delocalized lipophilic cation; MPT; membrane permeability transition; Auranofin; 2,3,4,6-tetra-; O; -acetyl-l-thio-β-; d; -glucopyranosato-S-triethylphosphine gold(I); TrxR; thioredoxin reductase; Trx; thioredoxin; [Au(dppe); 2; ]Cl; bis[1,2 bis(diphenylphosphino)ethane]gold(I) chloride; [Au(d2pypp); 2; ]Cl; bis[1,3-bis(di-2-pyridylphosphino)propane]gold(I) chlorideAntitumor agents; Mitochondria; Gold compounds; Apoptosis; Thioredoxin reductase; Thioredoxin
The influence of P2Y12 receptor deficiency on the platelet inhibitory activities of prasugrel in a mouse model: Evidence for specific inhibition of P2Y12 receptors by prasugrel by Masami Hashimoto; Atsuhiro Sugidachi; Takashi Isobe; Yoichi Niitsu; Taketoshi Ogawa; Joseph A. Jakubowski; Fumitoshi Asai (pp. 1003-1009).
Prasugrel is a novel orally active thienopyridine with faster, higher and more reliable inhibition of platelet aggregation than clopidogrel reflecting its metabolism in vivo to an active metabolite with selective P2Y12 antagonistic activity. Several lines of evidence support the contention that prasugrel provides selective P2Y12 receptor antagonistic activity. To date, however, direct evidence of P2Y12 specific action by prasugrel in vivo is limited. In the present study, effects of prasugrel on ex vivo platelet aggregation were examined in wild type (WT) and P2Y12−/− mice. In WT mice, prasugrel showed platelet inhibition that was 8.2 times more potent than clopidogrel. In P2Y12−/− mice, ADP induced platelet aggregation was minimal, and its extent was similar to that in prasugrel-treated WT mice. In addition, no further inhibition of platelet aggregation was observed after administration of prasugrel to P2Y12−/− mice. Furthermore, prasugrel-treated WT mice showed similar aggregation patterns using collagen- and murine PAR-4 agonist peptide to those of P2Y12−/− mice treated with vehicle or prasugrel. Overall, these results clearly provide additional in vivo evidence that prasugrel has selective P2Y12 antagonistic activity.
Keywords: Prasugrel; P2Y; 12; receptor; Platelet; ADP; Knockout mouse
The influence of P2Y12 receptor deficiency on the platelet inhibitory activities of prasugrel in a mouse model: Evidence for specific inhibition of P2Y12 receptors by prasugrel by Masami Hashimoto; Atsuhiro Sugidachi; Takashi Isobe; Yoichi Niitsu; Taketoshi Ogawa; Joseph A. Jakubowski; Fumitoshi Asai (pp. 1003-1009).
Prasugrel is a novel orally active thienopyridine with faster, higher and more reliable inhibition of platelet aggregation than clopidogrel reflecting its metabolism in vivo to an active metabolite with selective P2Y12 antagonistic activity. Several lines of evidence support the contention that prasugrel provides selective P2Y12 receptor antagonistic activity. To date, however, direct evidence of P2Y12 specific action by prasugrel in vivo is limited. In the present study, effects of prasugrel on ex vivo platelet aggregation were examined in wild type (WT) and P2Y12−/− mice. In WT mice, prasugrel showed platelet inhibition that was 8.2 times more potent than clopidogrel. In P2Y12−/− mice, ADP induced platelet aggregation was minimal, and its extent was similar to that in prasugrel-treated WT mice. In addition, no further inhibition of platelet aggregation was observed after administration of prasugrel to P2Y12−/− mice. Furthermore, prasugrel-treated WT mice showed similar aggregation patterns using collagen- and murine PAR-4 agonist peptide to those of P2Y12−/− mice treated with vehicle or prasugrel. Overall, these results clearly provide additional in vivo evidence that prasugrel has selective P2Y12 antagonistic activity.
Keywords: Prasugrel; P2Y; 12; receptor; Platelet; ADP; Knockout mouse
Antioxidant effects of 2,3-dihydro-5-hydroxy-4,6-di- tert-butyl-2,2-dipentylbenzofuran and α-tocopherol in hyperlipidemic mice as evaluated by hydroxyoctadecadienoic acid and 7-hydroxycholesterol by Yasukazu Yoshida; Mieko Hayakawa; Nanako Itoh; Yoko Habuchi; Ruriko Inoue; Zhi-Hua Chen; Jiaofei Cao; Osamu Cynshi; Kou-Ichi Jishage; Etsuo Niki (pp. 1010-1019).
It has been hypothesized that oxidative modification of low density lipoprotein plays a key role in the pathogenesis of atherosclerosis. In order to elucidate the role of lipid oxidation and its inhibition in vivo, apolipoprotein E and α-tocopherol (αT) transfer protein double knockout (ApoE−/−α-TTP−/−) and apolipoprotein E knockout (ApoE−/−) mice fed with a vitamin E-depleted diet and a diet containing 0.002wt.% αT, respectively, were used with or without the treatment of a synthetic antioxidant 2,3-dihydro-5-hydroxy-4,6-di- tert-butyl-2,2-dipentylbenzofuran (BO-653, 0.2wt.%). The lipid oxidation markers of total hydroxylinoleic acid (tHODE), 8- iso-prostaglandin F2α, and 7-hydroxycholesterol (t7-OHCh) in the blood, liver, and brain were inclusively measured with or without an excessive cholesterol-feeding (Ch-diet). The tHODE levels were elevated by Ch-diet in the plasma and brain of ApoE−/−α-TTP−/− mice and in the liver of ApoE−/− mice without BO-653. The levels of t7-OHCh in the liver were also increased due to the Ch-diet, and the ratio of t7-OHCh to the parent compound cholesterol was reduced to the control levels by BO-653.In summary, it was demonstrated by biomarkers, tHODE and t7-OHCh, that the added BO-653 in their diets exerted antioxidative effects in vivo under the condition of reduced vitamin E.
Keywords: Abbreviations; ApoE; −/−; apolipoprotein E knockout mice; BHT; 2,6-di-; tert; -butyl-4-methylphenol; BSTFA; N; ,; O; -bis(trimethylsilyl)trifluoroacetamide; BO-653; 2,3-dihydro-5-hydroxy-4,6-di-; tert; -butyl-2,2-dipentylbenzofuran; Ch; cholesterol; CoQ9; coenzyme Q; 9; (ubiquinol-9; +; ubiquinone-9); 7-OHCh; 7-hydroxychoresterol; GPT; glutamate pyruvate transaminase; tHODE; total hydroxyoctadecadienoic acid; HPODE; hydroperoxyoctadecadienoic acid; 8-; iso; -PGF; 2α; 8-; iso; -prostaglandin F; 2α; LDL; low density lipoprotein; PBS; phosphate-buffered saline; T; tocopherol; α-TTP; −/−; α-tocopherol transfer protein knockoutLipid peroxidation; Total hydroxyoctadecadienoic acid (tHODE); 7-Hydroxycholesterol (t7-OHCh); BO-653; Apolipoprotein E knockout mice (ApoE; −/−; ); Apolipoprotein E and α-tocopherol transfer protein double knockout (ApoE; −/−; α-TTP; −/−; ) mice
Antioxidant effects of 2,3-dihydro-5-hydroxy-4,6-di- tert-butyl-2,2-dipentylbenzofuran and α-tocopherol in hyperlipidemic mice as evaluated by hydroxyoctadecadienoic acid and 7-hydroxycholesterol by Yasukazu Yoshida; Mieko Hayakawa; Nanako Itoh; Yoko Habuchi; Ruriko Inoue; Zhi-Hua Chen; Jiaofei Cao; Osamu Cynshi; Kou-Ichi Jishage; Etsuo Niki (pp. 1010-1019).
It has been hypothesized that oxidative modification of low density lipoprotein plays a key role in the pathogenesis of atherosclerosis. In order to elucidate the role of lipid oxidation and its inhibition in vivo, apolipoprotein E and α-tocopherol (αT) transfer protein double knockout (ApoE−/−α-TTP−/−) and apolipoprotein E knockout (ApoE−/−) mice fed with a vitamin E-depleted diet and a diet containing 0.002wt.% αT, respectively, were used with or without the treatment of a synthetic antioxidant 2,3-dihydro-5-hydroxy-4,6-di- tert-butyl-2,2-dipentylbenzofuran (BO-653, 0.2wt.%). The lipid oxidation markers of total hydroxylinoleic acid (tHODE), 8- iso-prostaglandin F2α, and 7-hydroxycholesterol (t7-OHCh) in the blood, liver, and brain were inclusively measured with or without an excessive cholesterol-feeding (Ch-diet). The tHODE levels were elevated by Ch-diet in the plasma and brain of ApoE−/−α-TTP−/− mice and in the liver of ApoE−/− mice without BO-653. The levels of t7-OHCh in the liver were also increased due to the Ch-diet, and the ratio of t7-OHCh to the parent compound cholesterol was reduced to the control levels by BO-653.In summary, it was demonstrated by biomarkers, tHODE and t7-OHCh, that the added BO-653 in their diets exerted antioxidative effects in vivo under the condition of reduced vitamin E.
Keywords: Abbreviations; ApoE; −/−; apolipoprotein E knockout mice; BHT; 2,6-di-; tert; -butyl-4-methylphenol; BSTFA; N; ,; O; -bis(trimethylsilyl)trifluoroacetamide; BO-653; 2,3-dihydro-5-hydroxy-4,6-di-; tert; -butyl-2,2-dipentylbenzofuran; Ch; cholesterol; CoQ9; coenzyme Q; 9; (ubiquinol-9; +; ubiquinone-9); 7-OHCh; 7-hydroxychoresterol; GPT; glutamate pyruvate transaminase; tHODE; total hydroxyoctadecadienoic acid; HPODE; hydroperoxyoctadecadienoic acid; 8-; iso; -PGF; 2α; 8-; iso; -prostaglandin F; 2α; LDL; low density lipoprotein; PBS; phosphate-buffered saline; T; tocopherol; α-TTP; −/−; α-tocopherol transfer protein knockoutLipid peroxidation; Total hydroxyoctadecadienoic acid (tHODE); 7-Hydroxycholesterol (t7-OHCh); BO-653; Apolipoprotein E knockout mice (ApoE; −/−; ); Apolipoprotein E and α-tocopherol transfer protein double knockout (ApoE; −/−; α-TTP; −/−; ) mice
Upregulation of sodium-dependent vitamin C transporter 2 expression in adrenals increases norepinephrine production and aggravates hyperlipidemia in mice with streptozotocin-induced diabetes by Ximei Wu; Takuma Iguchi; Junko Hirano; Isami Fujita; Hidenori Ueda; Norio Itoh; Keiichi Tanaka; Tsuyoshi Nakanishi (pp. 1020-1028).
The hyperglycemia and hyperoxidation that characterize diabetes lead to reduced vitamin C (l-ascorbic acid, AA) levels in diabetic humans and animals. We examined the possibility that diabetes-induced low plasma AA levels impair AA distribution to various tissues and that these changes are closely related to the development of diabetic complications. AA levels were markedly decreased in the plasma and increased in the adrenals of mice with streptozotocin (STZ)-induced diabetes. Consistently with these results, in [1−14C]AA accumulation assays, the efficiency of [1−14C]AA accumulation was significantly higher in the adrenals (which had the greatest ability to accumulate [1−14C]AA) of diabetic mice than in those of controls. Expression of sodium-dependent vitamin C transporter (SVCT)-2, a transporter of AA, was upregulated in diabetic adrenals. Furthermore, increased AA incorporation into the diabetic adrenals by SVCT-2 led to increased plasma norepinephrine, triglyceride and free fatty acid levels in mice with STZ-induced diabetes. Therefore, oversupplementation with AA could be deleterious in diabetic patients, because overexpression of adrenal SVCT-2 in diabetes could lead to excessive AA uptake, thus enhancing norepinephrine production and exacerbating some diabetic complications. Interestingly, however, treatment with AA dose-dependently abolished the increased expression of adrenal SVCT-2 and normalized the abovementioned plasma parameters in diabetic mice. These results suggest SVCT-2-mediated increases in AA uptake by the adrenals followed by excessive production of plasma norepinephrine may play a pivotal role in the development of diabetic complications.
Keywords: Abbreviations; AA; l; -ascorbic acid; GLUT; glucose transporter; FFA; free fatty acid; NE; norepinephrine; HPLC; high performance liquid chromatography; STZ; streptozotocin; SVCT; sodium-dependent vitamin C transporter; TG; triglycerideSodium-dependent vitamin C transporter (SVCT); Ascorbic acid; Diabetes; Norepinephrine; Hyperlipidemia; Adrenal
Upregulation of sodium-dependent vitamin C transporter 2 expression in adrenals increases norepinephrine production and aggravates hyperlipidemia in mice with streptozotocin-induced diabetes by Ximei Wu; Takuma Iguchi; Junko Hirano; Isami Fujita; Hidenori Ueda; Norio Itoh; Keiichi Tanaka; Tsuyoshi Nakanishi (pp. 1020-1028).
The hyperglycemia and hyperoxidation that characterize diabetes lead to reduced vitamin C (l-ascorbic acid, AA) levels in diabetic humans and animals. We examined the possibility that diabetes-induced low plasma AA levels impair AA distribution to various tissues and that these changes are closely related to the development of diabetic complications. AA levels were markedly decreased in the plasma and increased in the adrenals of mice with streptozotocin (STZ)-induced diabetes. Consistently with these results, in [1−14C]AA accumulation assays, the efficiency of [1−14C]AA accumulation was significantly higher in the adrenals (which had the greatest ability to accumulate [1−14C]AA) of diabetic mice than in those of controls. Expression of sodium-dependent vitamin C transporter (SVCT)-2, a transporter of AA, was upregulated in diabetic adrenals. Furthermore, increased AA incorporation into the diabetic adrenals by SVCT-2 led to increased plasma norepinephrine, triglyceride and free fatty acid levels in mice with STZ-induced diabetes. Therefore, oversupplementation with AA could be deleterious in diabetic patients, because overexpression of adrenal SVCT-2 in diabetes could lead to excessive AA uptake, thus enhancing norepinephrine production and exacerbating some diabetic complications. Interestingly, however, treatment with AA dose-dependently abolished the increased expression of adrenal SVCT-2 and normalized the abovementioned plasma parameters in diabetic mice. These results suggest SVCT-2-mediated increases in AA uptake by the adrenals followed by excessive production of plasma norepinephrine may play a pivotal role in the development of diabetic complications.
Keywords: Abbreviations; AA; l; -ascorbic acid; GLUT; glucose transporter; FFA; free fatty acid; NE; norepinephrine; HPLC; high performance liquid chromatography; STZ; streptozotocin; SVCT; sodium-dependent vitamin C transporter; TG; triglycerideSodium-dependent vitamin C transporter (SVCT); Ascorbic acid; Diabetes; Norepinephrine; Hyperlipidemia; Adrenal
Effects of ( R, S)/( S, R)-4,5-bis(2-chloro-4-hydroxyphenyl)-2-imidazolines and ( R, S)/( S, R)-2,3-bis(2-chloro-4-hydroxyphenyl)piperazines on estrogen receptor alpha level and transcriptional activity in MCF-7 cells by Ioanna Laïos; Anny Cleeren; Guy Leclercq; Denis Nonclercq; Guy Laurent; Miriam Schlenk; Anja Wellner; Ronald Gust (pp. 1029-1038).
4,5-Diaryl-2-imidazolines (Ims) and 2,3-diarylpiperazines (Pips) belong to the type II class of estrogens. These compounds enhance ERα-mediated transcription of ERE-driven reporter genes in MCF-7 cells but do not compete with [3H]estradiol (E2) for receptor binding, because of distinct anchoring modes. The present study examined whether the estrogenic action of Ims and Pips is associated with a down regulation of ERα, as reported for conventional agonists. Im and Pip derivatives displaying a large spectrum of activities in three distinct ERE-dependent transactivation systems were selected for that purpose. ERα immunostaining as well as Western blotting analysis revealed that both classes of compounds down regulated ERα with an efficiency closely related to their transactivation potency. MG-132 abrogated this down regulation, pointing to a proteasomal degradation process. Ims and Pips with strong transactivation potency also altered [3H]E2 binding parameters, leading to a progressive decrease of cellular estrogen binding capacity. This property occurred largely before ERα down regulation and persisted even in presence of MG-132, indicating that it did not result from ERα breakdown but rather from a conformational change of the receptor. The additional finding that the most active agonist tested in this study enhanced the capacity of a purified ERα recombinant to recruit LxxLL co-activators, while its inactive counterpart failed to do so confirmed this hypothesis. Altogether, our data indicate that the association of Ims and Pips with ERα elicits similar responses to conventional agonists, even if they interact with distinct residues of the binding pocket.
Keywords: Estrogen receptor α; Down regulation; Binding capacity; Transactivation; MCF-7 cells; 4,5-Bis(2-chloro-4-hydroxyphenyl)-2-imidazolines; 2,3-Bis(2-chloro-4-hydroxyphenyl) piperazines
Effects of ( R, S)/( S, R)-4,5-bis(2-chloro-4-hydroxyphenyl)-2-imidazolines and ( R, S)/( S, R)-2,3-bis(2-chloro-4-hydroxyphenyl)piperazines on estrogen receptor alpha level and transcriptional activity in MCF-7 cells by Ioanna Laïos; Anny Cleeren; Guy Leclercq; Denis Nonclercq; Guy Laurent; Miriam Schlenk; Anja Wellner; Ronald Gust (pp. 1029-1038).
4,5-Diaryl-2-imidazolines (Ims) and 2,3-diarylpiperazines (Pips) belong to the type II class of estrogens. These compounds enhance ERα-mediated transcription of ERE-driven reporter genes in MCF-7 cells but do not compete with [3H]estradiol (E2) for receptor binding, because of distinct anchoring modes. The present study examined whether the estrogenic action of Ims and Pips is associated with a down regulation of ERα, as reported for conventional agonists. Im and Pip derivatives displaying a large spectrum of activities in three distinct ERE-dependent transactivation systems were selected for that purpose. ERα immunostaining as well as Western blotting analysis revealed that both classes of compounds down regulated ERα with an efficiency closely related to their transactivation potency. MG-132 abrogated this down regulation, pointing to a proteasomal degradation process. Ims and Pips with strong transactivation potency also altered [3H]E2 binding parameters, leading to a progressive decrease of cellular estrogen binding capacity. This property occurred largely before ERα down regulation and persisted even in presence of MG-132, indicating that it did not result from ERα breakdown but rather from a conformational change of the receptor. The additional finding that the most active agonist tested in this study enhanced the capacity of a purified ERα recombinant to recruit LxxLL co-activators, while its inactive counterpart failed to do so confirmed this hypothesis. Altogether, our data indicate that the association of Ims and Pips with ERα elicits similar responses to conventional agonists, even if they interact with distinct residues of the binding pocket.
Keywords: Estrogen receptor α; Down regulation; Binding capacity; Transactivation; MCF-7 cells; 4,5-Bis(2-chloro-4-hydroxyphenyl)-2-imidazolines; 2,3-Bis(2-chloro-4-hydroxyphenyl) piperazines
GEA 3162, a peroxynitrite donor, induces Bcl-2-sensitive, p53-independent apoptosis in murine bone marrow cells by Emma L. Taylor; John T. Li; Joan C. Tupper; Adriano G. Rossi; Robert K. Winn; John M. Harlan (pp. 1039-1049).
Apoptosis may be regulated by oxidants such as peroxynitrite (ONOO−). The tumour suppressor, p53, has been reported to play a crucial role in apoptosis induced by oxidants, therefore we assessed the ability of a ONOO− donor, GEA 3162, to activate caspases and induce mitochondrial permeability in a p53-deficient murine bone marrow cell line, Jaws II. Furthermore, these cells were stably transfected with Bcl-2, in order to investigate the impact of this survival protein on ONOO−-induced apoptosis. GEA 3162 activated caspases and induced loss of mitochondrial membrane potential in Jaws II cells. In particular, caspases 3 and 2 were activated, alongside minor activation of caspases 8 and 9, and apoptosis was partially dependent upon p38 MAP kinase activation, with little or no role for JNK. Overexpression of Bcl-2 abolished activation of all caspases and reduced the change in mitochondrial membrane potential. Thus, we have demonstrated that the ONOO− donor, GEA 3162, induces apoptosis in Jaws II murine myeloid cells despite lacking functional p53, via a pathway that principally involves caspases 2 and 3 and mitochondrial changes. This is blocked by overexpression of Bcl-2 via a mechanism that does not appear to merely reflect stabilisation of the mitochondrial membrane.
Keywords: Abbreviations; GEA 3162; 1,2,3,4-oxatriazolium,5-amino-3-(3,4-dichlorophenyl)-chloride; STSP; staurosporine; GFP; green fluorescent protein; Jaws II-GFP; p53-deficient murine bone marrow cells stably transfected with a vector encoding GFP; Jaws II-Bcl-2; p53-deficient murine bone marrow cells stably transfected with a vector encoding GFP and the survival protein Bcl-2; JNK; c-Jun N-terminal kinase; MAP kinase; mitogen activated protein kinase; NO; nitric oxide; ONOO; −; peroxynitritePeroxynitrite; Apoptosis; Caspase; p53; Bcl-2; Myeloid
GEA 3162, a peroxynitrite donor, induces Bcl-2-sensitive, p53-independent apoptosis in murine bone marrow cells by Emma L. Taylor; John T. Li; Joan C. Tupper; Adriano G. Rossi; Robert K. Winn; John M. Harlan (pp. 1039-1049).
Apoptosis may be regulated by oxidants such as peroxynitrite (ONOO−). The tumour suppressor, p53, has been reported to play a crucial role in apoptosis induced by oxidants, therefore we assessed the ability of a ONOO− donor, GEA 3162, to activate caspases and induce mitochondrial permeability in a p53-deficient murine bone marrow cell line, Jaws II. Furthermore, these cells were stably transfected with Bcl-2, in order to investigate the impact of this survival protein on ONOO−-induced apoptosis. GEA 3162 activated caspases and induced loss of mitochondrial membrane potential in Jaws II cells. In particular, caspases 3 and 2 were activated, alongside minor activation of caspases 8 and 9, and apoptosis was partially dependent upon p38 MAP kinase activation, with little or no role for JNK. Overexpression of Bcl-2 abolished activation of all caspases and reduced the change in mitochondrial membrane potential. Thus, we have demonstrated that the ONOO− donor, GEA 3162, induces apoptosis in Jaws II murine myeloid cells despite lacking functional p53, via a pathway that principally involves caspases 2 and 3 and mitochondrial changes. This is blocked by overexpression of Bcl-2 via a mechanism that does not appear to merely reflect stabilisation of the mitochondrial membrane.
Keywords: Abbreviations; GEA 3162; 1,2,3,4-oxatriazolium,5-amino-3-(3,4-dichlorophenyl)-chloride; STSP; staurosporine; GFP; green fluorescent protein; Jaws II-GFP; p53-deficient murine bone marrow cells stably transfected with a vector encoding GFP; Jaws II-Bcl-2; p53-deficient murine bone marrow cells stably transfected with a vector encoding GFP and the survival protein Bcl-2; JNK; c-Jun N-terminal kinase; MAP kinase; mitogen activated protein kinase; NO; nitric oxide; ONOO; −; peroxynitritePeroxynitrite; Apoptosis; Caspase; p53; Bcl-2; Myeloid
The non-steroidal anti-inflammatory drug piroxicam blocks ligand binding to the formyl peptide receptor but not the formyl peptide receptor like 1 by A.-L. Stenfeldt; J. Karlsson; C. Wennerås; J. Bylund; H. Fu; C. Dahlgren (pp. 1050-1056).
The anti-inflammatory drug piroxicam has been reported to affect the production of reactive oxygen species in phagocytes. This anti-inflammatory effect is thought to be mediated through inhibition of cyclooxygenase (COX), an enzyme important for prostaglandin synthesis. We have compared the effects of piroxicam on superoxide production mediated by two closely related G-protein coupled receptors expressed on neutrophils, the formyl peptide receptor (FPR) and the formyl peptide receptor like 1 (FPRL1). Neutrophils were stimulated with agonists that bind specifically to FPR (the peptide ligand N-formyl-Met-Leu-Phe, fMLF) or FPRL1 (the peptide ligand Trp-Lys-Tyr-Met-Val-L-Met-NH2, WKYMVM) or both of these receptors (the peptide ligand Trp-Lys-Tyr-Met-Val-D-Met-NH2, WKYMVm). Piroxicam reduced the neutrophil superoxide production induced by the FPR agonist but had no significant effect on the FPRL1 induced response. Neutrophil intracellular calcium changes induced by the agonist WKYMVm (that triggers both FPR and FPRL1) were only inhibited by piroxicam when the drug was combined with the FPRL1 specific antagonist, Trp-Arg-Trp-Trp-Trp-Trp (WRW4), and this was true also for the inhibition of superoxide anion release. Receptor-binding analysis showed that the fluorescently labelled FPR specific ligand N-formyl-Nle-Leu-Phe-Nle-Tyr-Lys (fNLFNYK), was competed for in a dose-dependent manner, by the FPR ligand fMLF and as well as by piroxicam.We show that piroxicam inhibits the neutrophil responses triggered through FPR, but not through FPRL1 and this inhibition is due to a reduced binding of the activating ligand to its cell surface receptor.
Keywords: Neutrophil; Formyl peptide receptor; Formyl peptide receptor like 1; Non-steroidal anti-inflammatory drug; Piroxicam; Inhibitor
The non-steroidal anti-inflammatory drug piroxicam blocks ligand binding to the formyl peptide receptor but not the formyl peptide receptor like 1 by A.-L. Stenfeldt; J. Karlsson; C. Wennerås; J. Bylund; H. Fu; C. Dahlgren (pp. 1050-1056).
The anti-inflammatory drug piroxicam has been reported to affect the production of reactive oxygen species in phagocytes. This anti-inflammatory effect is thought to be mediated through inhibition of cyclooxygenase (COX), an enzyme important for prostaglandin synthesis. We have compared the effects of piroxicam on superoxide production mediated by two closely related G-protein coupled receptors expressed on neutrophils, the formyl peptide receptor (FPR) and the formyl peptide receptor like 1 (FPRL1). Neutrophils were stimulated with agonists that bind specifically to FPR (the peptide ligand N-formyl-Met-Leu-Phe, fMLF) or FPRL1 (the peptide ligand Trp-Lys-Tyr-Met-Val-L-Met-NH2, WKYMVM) or both of these receptors (the peptide ligand Trp-Lys-Tyr-Met-Val-D-Met-NH2, WKYMVm). Piroxicam reduced the neutrophil superoxide production induced by the FPR agonist but had no significant effect on the FPRL1 induced response. Neutrophil intracellular calcium changes induced by the agonist WKYMVm (that triggers both FPR and FPRL1) were only inhibited by piroxicam when the drug was combined with the FPRL1 specific antagonist, Trp-Arg-Trp-Trp-Trp-Trp (WRW4), and this was true also for the inhibition of superoxide anion release. Receptor-binding analysis showed that the fluorescently labelled FPR specific ligand N-formyl-Nle-Leu-Phe-Nle-Tyr-Lys (fNLFNYK), was competed for in a dose-dependent manner, by the FPR ligand fMLF and as well as by piroxicam.We show that piroxicam inhibits the neutrophil responses triggered through FPR, but not through FPRL1 and this inhibition is due to a reduced binding of the activating ligand to its cell surface receptor.
Keywords: Neutrophil; Formyl peptide receptor; Formyl peptide receptor like 1; Non-steroidal anti-inflammatory drug; Piroxicam; Inhibitor
Evidence that genetic deletion of the TNF receptor p60 or p80 inhibits Fas mediated apoptosis in macrophages by Yasunari Takada; Bokyung Sung; Gautam Sethi; Madan M. Chaturvedi; Bharat B. Aggarwal (pp. 1057-1064).
Almost 19 members of the tumor necrosis factor (TNF) superfamily have been identified that interact with 29 different receptors. Whether these receptors communicate with each other is not understood. Recently, we have shown that receptor activator of NF-κB ligand signaling is modulated by genetic deletion of the TNF receptor. In the current report, we investigated the possibility of a cross-talk between Fas and TNF-α signaling pathway in macrophage cell lines derived from wild-type (WT) mice and from mice with genetic deletion of the type 1 TNF receptor (p60−/−), the type 2 TNF receptor (p80−/−), or both receptors (p60−/−p80−/−). We found that the macrophages expressing TNF receptors were highly sensitive to apoptosis induced by anti-Fas. The genetic deletion of TNF receptors, however, made the cells resistance to anti-Fas-induced apoptosis. Anti-Fas induced activation of caspase-3 and PARP cleavage in WT cells but not in TNF receptor-deleted cells. This difference was found to be independent of the expression of Fas, Fas-associated protein with death domain (FADD) or TNF receptor-associated death domain (TRADD). We found that anti-Fas induced recruitment of TNFR1 into Fas-complex. We also found that TRADD, which mediates TNF signaling, was constitutively bound to Fas receptor in TNF receptor-deleted cells but not in wild-type cells. Transient transfection of TNFR1 in TNFR1-deleted cells sensitized them to anti-Fas-induced apoptosis. Overall our results demonstrate that Fas signaling is modulated by the TNF receptors and thus provide the evidence of cross-talk between the receptors of two cytokines.
Keywords: Abbreviations; TNF; tumor necrosis factor; TNFR; TNF receptor; NF-κB; nuclear factor-κB; RANK; receptor activator of NF-κB; RANKL; receptor activator of NF-κB ligand; IκB; inhibitory subunit of NF-κB; IKK; IκBα kinase; TRAF; TNF receptor-associated factor; TRADD; TNF receptor-associated death domain; FADD; Fas associated protein with death domain; NIK; NF-κB-inducing kinase; JNK; c-Jun N-terminal kinase; MAPK; mitogen-activated protein kinaseFas; TNFR; Apoptosis; NF-κB; Macrophages
Evidence that genetic deletion of the TNF receptor p60 or p80 inhibits Fas mediated apoptosis in macrophages by Yasunari Takada; Bokyung Sung; Gautam Sethi; Madan M. Chaturvedi; Bharat B. Aggarwal (pp. 1057-1064).
Almost 19 members of the tumor necrosis factor (TNF) superfamily have been identified that interact with 29 different receptors. Whether these receptors communicate with each other is not understood. Recently, we have shown that receptor activator of NF-κB ligand signaling is modulated by genetic deletion of the TNF receptor. In the current report, we investigated the possibility of a cross-talk between Fas and TNF-α signaling pathway in macrophage cell lines derived from wild-type (WT) mice and from mice with genetic deletion of the type 1 TNF receptor (p60−/−), the type 2 TNF receptor (p80−/−), or both receptors (p60−/−p80−/−). We found that the macrophages expressing TNF receptors were highly sensitive to apoptosis induced by anti-Fas. The genetic deletion of TNF receptors, however, made the cells resistance to anti-Fas-induced apoptosis. Anti-Fas induced activation of caspase-3 and PARP cleavage in WT cells but not in TNF receptor-deleted cells. This difference was found to be independent of the expression of Fas, Fas-associated protein with death domain (FADD) or TNF receptor-associated death domain (TRADD). We found that anti-Fas induced recruitment of TNFR1 into Fas-complex. We also found that TRADD, which mediates TNF signaling, was constitutively bound to Fas receptor in TNF receptor-deleted cells but not in wild-type cells. Transient transfection of TNFR1 in TNFR1-deleted cells sensitized them to anti-Fas-induced apoptosis. Overall our results demonstrate that Fas signaling is modulated by the TNF receptors and thus provide the evidence of cross-talk between the receptors of two cytokines.
Keywords: Abbreviations; TNF; tumor necrosis factor; TNFR; TNF receptor; NF-κB; nuclear factor-κB; RANK; receptor activator of NF-κB; RANKL; receptor activator of NF-κB ligand; IκB; inhibitory subunit of NF-κB; IKK; IκBα kinase; TRAF; TNF receptor-associated factor; TRADD; TNF receptor-associated death domain; FADD; Fas associated protein with death domain; NIK; NF-κB-inducing kinase; JNK; c-Jun N-terminal kinase; MAPK; mitogen-activated protein kinaseFas; TNFR; Apoptosis; NF-κB; Macrophages
Cytotoxicity of β-carbolines in dopamine transporter expressing cells: Structure–activity relationships by Catrin Wernicke; Yvonne Schott; Christoph Enzensperger; Gert Schulze; Jochen Lehmann; Hans Rommelspacher (pp. 1065-1077).
Some β-carbolines (BC) are natural constituents in the human brain deriving from tryptophan, tryptamine, and serotonin. In vitro and animal experiments suggest that BC-cations may cause neurodegeneration with a higher vulnerability of dopaminergic than of other neurons. Despite the possible implication of the BC-cations in the pathogenesis of Parkinson's disease (PD), the underlying mechanisms are poorly understood. The present study further explores the structural requirements for the cytotoxic effects of BCs and searches for additional compounds involved in the pathogenesis of PD. Previous studies were now extended to serotonin-derived BCs, tetrahydro-BCs, a BC-dimer, and a BC-enantiomer to reveal possible stereoselectivity.Neutral, rather lipophilic BCs may pass the plasma membrane and the outer and inner mitochondrial membranes by diffusion whereas the cationic, more polar compounds, can be transported by the dopamine transporter (DAT). In the present study, 4 out of 17 BC-cations caused DAT-independent toxicity. This number is unexpected in view of previous findings that all BC-cations are transported by DAT. 3-Carboxylated and 6-methoxylated BCs were poor substrates. The size alone does not seem to be a limiting factor. A dimeric BC-cation was readily transported by the DAT despite its much larger structure compared to dopamine. Furthermore, ( R)-enantiomers were preferentially transported. The neutral BCs were approximately one order of magnitude less toxic than the cationic BCs. There are considerable differences of the transport efficiency between the BCs. Potent cytotoxic tetrahydro-BCs were detected. Because precursor tetrahydro-BCs are present in the brain, the search for the occurrence of these compounds in human brain is warranted.
Keywords: β-Carbolines; Dopamine transporter; Neurotoxin; Stereoselectivity; Parkinson's disease
Cytotoxicity of β-carbolines in dopamine transporter expressing cells: Structure–activity relationships by Catrin Wernicke; Yvonne Schott; Christoph Enzensperger; Gert Schulze; Jochen Lehmann; Hans Rommelspacher (pp. 1065-1077).
Some β-carbolines (BC) are natural constituents in the human brain deriving from tryptophan, tryptamine, and serotonin. In vitro and animal experiments suggest that BC-cations may cause neurodegeneration with a higher vulnerability of dopaminergic than of other neurons. Despite the possible implication of the BC-cations in the pathogenesis of Parkinson's disease (PD), the underlying mechanisms are poorly understood. The present study further explores the structural requirements for the cytotoxic effects of BCs and searches for additional compounds involved in the pathogenesis of PD. Previous studies were now extended to serotonin-derived BCs, tetrahydro-BCs, a BC-dimer, and a BC-enantiomer to reveal possible stereoselectivity.Neutral, rather lipophilic BCs may pass the plasma membrane and the outer and inner mitochondrial membranes by diffusion whereas the cationic, more polar compounds, can be transported by the dopamine transporter (DAT). In the present study, 4 out of 17 BC-cations caused DAT-independent toxicity. This number is unexpected in view of previous findings that all BC-cations are transported by DAT. 3-Carboxylated and 6-methoxylated BCs were poor substrates. The size alone does not seem to be a limiting factor. A dimeric BC-cation was readily transported by the DAT despite its much larger structure compared to dopamine. Furthermore, ( R)-enantiomers were preferentially transported. The neutral BCs were approximately one order of magnitude less toxic than the cationic BCs. There are considerable differences of the transport efficiency between the BCs. Potent cytotoxic tetrahydro-BCs were detected. Because precursor tetrahydro-BCs are present in the brain, the search for the occurrence of these compounds in human brain is warranted.
Keywords: β-Carbolines; Dopamine transporter; Neurotoxin; Stereoselectivity; Parkinson's disease
Ursolic acid ameliorates cognition deficits and attenuates oxidative damage in the brain of senescent mice induced byd-galactose by Jun Lu; Yuan-Lin Zheng; Dong-Mei Wu; Lan Luo; Dong-Xu Sun; Qun Shan (pp. 1078-1090).
Ursolic acid (UA), a pentracyclic triterpene, is reported to have an antioxidant activity. Here we assessed the protective effect of UA against thed-galactose (d-gal)-induced neurotoxicity. We found that UA markedly reversed thed-gal induced learning and memory impairment by behavioral tests. The following antioxidant defense enzymes were measured: superoxide dismutases (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR). The content of the lipid peroxidation product malondialdehyde (MDA) was also analyzed. Our results indicated that the neuroprotective effect of UA againstd-gal induced neurotoxicity might be caused, at least in part, by the increase in the activity of antioxidant enzymes with a reduction in lipid peroxidation. And UA also inhibited the activation of caspase-3 induced byd-gal. Furthermore, we found that UA significantly increased the level of growth-associated protein GAP43 in the brain ofd-gal-treated mice. These results suggest that the pharmacological action of UA may offer a novel therapeutic strategy for the treatment of age-related conditions.
Keywords: Abbreviations; CAT; catalase; Ctrl; control; d; -gal; d; -galactose; GAP43; growth associated protein 43; GR; glutathione reductase; GPx; glutathione peroxidase; MDA; malondialdehyde; SOD; superoxide dismutases; UA; Ursolic acidUrsolic acid; d; -Galactose; ROS; Behavior; Antioxidant enzyme; Caspase-3; GAP43
Ursolic acid ameliorates cognition deficits and attenuates oxidative damage in the brain of senescent mice induced byd-galactose by Jun Lu; Yuan-Lin Zheng; Dong-Mei Wu; Lan Luo; Dong-Xu Sun; Qun Shan (pp. 1078-1090).
Ursolic acid (UA), a pentracyclic triterpene, is reported to have an antioxidant activity. Here we assessed the protective effect of UA against thed-galactose (d-gal)-induced neurotoxicity. We found that UA markedly reversed thed-gal induced learning and memory impairment by behavioral tests. The following antioxidant defense enzymes were measured: superoxide dismutases (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR). The content of the lipid peroxidation product malondialdehyde (MDA) was also analyzed. Our results indicated that the neuroprotective effect of UA againstd-gal induced neurotoxicity might be caused, at least in part, by the increase in the activity of antioxidant enzymes with a reduction in lipid peroxidation. And UA also inhibited the activation of caspase-3 induced byd-gal. Furthermore, we found that UA significantly increased the level of growth-associated protein GAP43 in the brain ofd-gal-treated mice. These results suggest that the pharmacological action of UA may offer a novel therapeutic strategy for the treatment of age-related conditions.
Keywords: Abbreviations; CAT; catalase; Ctrl; control; d; -gal; d; -galactose; GAP43; growth associated protein 43; GR; glutathione reductase; GPx; glutathione peroxidase; MDA; malondialdehyde; SOD; superoxide dismutases; UA; Ursolic acidUrsolic acid; d; -Galactose; ROS; Behavior; Antioxidant enzyme; Caspase-3; GAP43