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1.
Nat Commun ; 11(1): 1058, 2020 02 26.
Artigo em Inglês | MEDLINE | ID: mdl-32103002

RESUMO

Angiotensin-converting enzyme 2 (ACE2) is critically involved in cardiovascular physiology and pathology, and is currently clinically evaluated to treat acute lung failure. Here we show that the B38-CAP, a carboxypeptidase derived from Paenibacillus sp. B38, is an ACE2-like enzyme to decrease angiotensin II levels in mice. In protein 3D structure analysis, B38-CAP homolog shares structural similarity to mammalian ACE2 with low sequence identity. In vitro, recombinant B38-CAP protein catalyzed the conversion of angiotensin II to angiotensin 1-7, as well as other known ACE2 target peptides. Treatment with B38-CAP suppressed angiotensin II-induced hypertension, cardiac hypertrophy, and fibrosis in mice. Moreover, B38-CAP inhibited pressure overload-induced pathological hypertrophy, myocardial fibrosis, and cardiac dysfunction in mice. Our data identify the bacterial B38-CAP as an ACE2-like carboxypeptidase, indicating that evolution has shaped a bacterial carboxypeptidase to a human ACE2-like enzyme. Bacterial engineering could be utilized to design improved protein drugs for hypertension and heart failure.


Assuntos
Carboxipeptidases/farmacologia , Cardiomegalia/tratamento farmacológico , Fibrose/tratamento farmacológico , Hipertensão/tratamento farmacológico , Paenibacillus/enzimologia , Peptidil Dipeptidase A/genética , Angiotensina II/metabolismo , Enzima de Conversão de Angiotensina 2 , Animais , Cardiomegalia/patologia , Modelos Animais de Doenças , Fibrose/patologia , Insuficiência Cardíaca/tratamento farmacológico , Insuficiência Cardíaca/prevenção & controle , Hipertensão/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Peptidil Dipeptidase A/metabolismo , Proteínas Recombinantes/farmacologia
2.
Ann N Y Acad Sci ; 1421(1): 37-45, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29740830

RESUMO

Translin and translin-associated factor X (translin/TRAX) proteins have been implicated in a variety of cellular activities central to nucleic acid metabolism. Accumulating evidence indicates that translin/TRAX complexes participate in processes ensuring the replication of DNA, as well as cell division. Significant progress has been made in understanding the roles of translin/TRAX complexes in RNA metabolism, such as through RNA-induced silencing complex activation or the microRNA depletion that occurs in Dicer deficiency. At the cellular level, translin-deficient (Tsn-/- ) mice display delayed endochondral ossification or progressive bone marrow failure with ectopic osteogenesis and adipogenesis, suggesting involvement in mesenchymal cell differentiation. In this review, we summarize the molecular and cellular functions of translin homo-octamer and translin/TRAX hetero-octamer. Finally, we discuss the multifaceted roles of translin, TRAX, and associated proteins in the healthy and disease states.


Assuntos
Diferenciação Celular/fisiologia , Proteínas de Ligação a DNA/fisiologia , Mesoderma/citologia , Animais , Divisão Celular/fisiologia , Dano ao DNA , Replicação do DNA , Proteínas de Ligação a DNA/genética , Humanos , Camundongos , Camundongos Knockout , MicroRNAs/genética , RNA/metabolismo , Ribonuclease III/genética
3.
J Biochem ; 164(2): 103-112, 2018 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-29490036

RESUMO

Paenidase is the first micro-organism-derived d-aspartyl endopeptidase that specifically recognizes an internal d-Asp residue to cleave [d-Asp]-X peptide bonds. Using peptide sequences obtained from the protein, we performed PCR with degenerate primers to amplify the paenidase I-encoding gene. Nucleotide sequencing revealed that mature paenidase I consist of 322 amino acid residues and that the protein is encoded as a pro-protein with a 197-amino-acid N-terminal extension compared to the mature protein. Paenidase I exhibits amino acid sequence similarity to several penicillin-binding proteins. In addition, paenidase I was classified into peptidase family S12 based on a MEROPS database search. Family S12 contains serine-type d-Ala-d-Ala carboxypeptidases that have three active site residues (Ser, Lys and Tyr) in the conserved motifs Ser-Xaa-Thr-Lys and Tyr-Xaa-Asn. These motifs were conserved in the primary structure of paenidase I, and the role of these residues was confirmed by site-directed mutagenesis.


Assuntos
Ácido Aspártico Endopeptidases/metabolismo , Clonagem Molecular , Paenibacillus/enzimologia , Ácido Aspártico Endopeptidases/química , Ácido Aspártico Endopeptidases/genética , Conformação Proteica
4.
Biosci Microbiota Food Health ; 34(2): 45-52, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25918672

RESUMO

A bacterial community analysis, using a culture-independent method (polymerase chain reaction-denaturing gradient gel electrophoresis), detected 17 species of bacteria including species of the genera Tetragenococcus, Lactobacillus, Pediococcus, Weissella Halanaerobium, Clostridium, and Sphingomonas in a traditional salty-fermented fish paste known as pla-ra or pa-daek in Thailand and Laos, which is used as a storage-stable multi-purpose seasoning. The representative genus of lactic acid bacteria seemed to vary in the 10 products collected from Thailand and Laos. Tetragenococci were common in products from central Thailand and Vientiane in Laos which had salinities of not less than 11% and pH values ranging from 5.6 to 6.1. However, lactobacilli were common in products from northern Thailand which had the lowest salinities (8.3-8.6%) and pH values (4.5-4.8) of all the samples examined. Two Lactobacillus and one Tetragenococcus species were detected in one product from northeastern Thailand containing 10% salt. These results suggest that salinity in pla-ra/pa-daek is an important determinant of the representative genus of lactic acid bacteria such as, Tetragenococcus or Lactobacillus. Additionally, differences in the acidity between these two groups seemed to be related to the production of d-/l-lactic acid in the lactic acid bacteria in each product. This is the first study to report a correlation between bacterial community structure and taste components in pla-ra/pa-daek products from various regions. This scientific work on a traditional fermented food will be useful in helping local producers meet differing consumer preferences in various regions.

5.
Plant Sci ; 233: 155-164, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25711823

RESUMO

Nitrification, the biological oxidation of ammonium to nitrate, weakens the soil's ability to retain N and facilitates N-losses from production agriculture through nitrate-leaching and denitrification. This process has a profound influence on what form of mineral-N is absorbed, used by plants, and retained in the soil, or lost to the environment, which in turn affects N-cycling, N-use efficiency (NUE) and ecosystem health and services. As reactive-N is often the most limiting in natural ecosystems, plants have acquired a range of mechanisms that suppress soil-nitrifier activity to limit N-losses via N-leaching and denitrification. Plants' ability to produce and release nitrification inhibitors from roots and suppress soil-nitrifier activity is termed 'biological nitrification inhibition' (BNI). With recent developments in methodology for in-situ measurement of nitrification inhibition, it is now possible to characterize BNI function in plants. This review assesses the current status of our understanding of the production and release of biological nitrification inhibitors (BNIs) and their potential in improving NUE in agriculture. A suite of genetic, soil and environmental factors regulate BNI activity in plants. BNI-function can be genetically exploited to improve the BNI-capacity of major food- and feed-crops to develop next-generation production systems with reduced nitrification and N2O emission rates to benefit both agriculture and the environment. The feasibility of such an approach is discussed based on the progresses made.


Assuntos
Nitrificação , Nitrogênio/metabolismo , Plantas/metabolismo , Solo/química , Agricultura , Óxido Nitroso/metabolismo , Plantas/genética
6.
APMIS ; 120(9): 706-11, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22882259

RESUMO

Adrenomedullin (AM) is a hypotension-causing peptide that was originally isolated from human pheochromocytoma cells, and it has been found to be expressed in various organs, including the liver. As the individual physiological and pathophysiological properties of AM peptide in the liver during endotoxemia in vivo has not yet been examined, we investigated this in experimental endotoxemia using heterozygote AM-deficient (AM(+/-)) mice. The AM concentration of AM(+/-) mice was significantly lesser than that of wild-type (WT) mice in lipopolysaccharide (LPS)-induced endotoxemia. After administering LPS, the survival rate for AM(+/-) mice was significantly lower than that for WT mice. Also, expressions of IL-1ß mRNA, and TNF-α mRNA, and NF-κB p65 in the liver were markedly increased and serum ALT greatly elevated in comparison with WT mice. However, supplementation of exogenous AM reversed the deteriorations in mortality and inflammatory responses. Therefore, we conclude that AM plays an important role in regulating systemic inflammation and may be an important intrinsic factor for protecting against liver damage in LPS-induced endotoxemia.


Assuntos
Adrenomedulina/imunologia , Endotoxemia/imunologia , Fígado/imunologia , Adrenomedulina/sangue , Adrenomedulina/genética , Alanina Transaminase/sangue , Animais , Endotoxemia/sangue , Endotoxemia/genética , Imuno-Histoquímica , Interleucina-1beta/genética , Interleucina-1beta/imunologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , NF-kappa B/sangue , NF-kappa B/imunologia , RNA Mensageiro/química , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/imunologia
8.
New Phytol ; 180(2): 442-451, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18657214

RESUMO

Nitrification results in poor nitrogen (N) recovery and negative environmental impacts in most agricultural systems. Some plant species release secondary metabolites from their roots that inhibit nitrification, a phenomenon known as biological nitrification inhibition (BNI). Here, we attempt to characterize BNI in sorghum (Sorghum bicolor). In solution culture, the effect of N nutrition and plant age was studied on BNI activity from roots. A bioluminescence assay using recombinant Nitrosomonas europaea was employed to determine the inhibitory effect of root exudates. One major active constituent was isolated by activity-guided HPLC fractionations. The structure was analysed using NMR and mass spectrometry. Properties and the 70% inhibitory concentration (IC(70)) of this compound were determined by in vitro assay. Sorghum had significant BNI capacity, releasing 20 allylthiourea units (ATU) g(-1) root DW d(-1). Release of BNI compounds increased with growth stage and concentration of supply. NH4+ -grown plants released several-fold higher BNI compounds than NO3- -grown plants. The active constituent was identified as methyl 3-(4-hydroxyphenyl) propionate. BNI compound release from roots is a physiologically active process, stimulated by the presence of NH4+. Methyl 3-(4-hydroxyphenyl) propionate is the first compound purified from the root exudates of any species; this is an important step towards better understanding BNI in sorghum.


Assuntos
Inibidores Enzimáticos/metabolismo , Nitrogênio/metabolismo , Fenóis/metabolismo , Propionatos/metabolismo , Sorghum/metabolismo , Inibidores Enzimáticos/isolamento & purificação , Hidroxilamina/farmacologia , Estrutura Molecular , Fenóis/química , Fenóis/isolamento & purificação , Exsudatos de Plantas , Raízes de Plantas/química , Raízes de Plantas/metabolismo , Propionatos/química , Propionatos/isolamento & purificação , Sorghum/química
9.
Biol Pharm Bull ; 31(2): 207-11, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18239274

RESUMO

The integrity of the genome is threatened by DNA damaging events such as radiation, viral infection and chemicals. Ionizing irradiation is known to cause genotoxic damage through the generation of reactive oxygen species (ROS) and nitrogen species (RNS) and we have found that a signaling pathway for the nuclear translocation of Translin is initiated in association and efficiently blocked by a specific inhibitor of nitric oxide synthase (NOS). This suggests the involvement of inducible nitric oxide synthase (iNOS)-derived nitric oxide (NO) in the nuclear translocation of Translin. To address the functional significance of Translin in the hematopoietic generation system after ionizing irradiation, we generated Translin-deficient (Translin(-/-)) mice and examined hematopoietic colony formation after sublethal ionizing irradiation. We thereby confirmed a severe delay of colony formation in the spleens of Translin(-/-) as compared with Translin(+/+) mice. Taken together, the results suggest that Translin contributes to hematopoietic regeneration by acting as a sensor protein for radiation-induced damage.


Assuntos
Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/fisiologia , Sistema Hematopoético/fisiologia , Sistema Hematopoético/efeitos da radiação , Animais , Ciclo Celular/genética , Ciclo Celular/fisiologia , Núcleo Celular/genética , Núcleo Celular/fisiologia , Citosol/fisiologia , Dano ao DNA , Eletroforese em Gel de Poliacrilamida , Raios gama , Humanos , Immunoblotting , Células K562 , Camundongos , Camundongos Knockout , Estresse Oxidativo/fisiologia , Proteínas de Ligação a RNA , Regeneração/fisiologia , Regeneração/efeitos da radiação
10.
Biopsychosoc Med ; 1: 10, 2007 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-17470298

RESUMO

AIMS: The aim of this study was to investigate the effect of juggling therapy for anxiety disorder patients. DESIGN AND METHOD: Subjects were 17 female outpatients who met the DSM-IV diagnostic criteria for anxiety disorders. Subjects were treated with standard psychotherapy, medication and counseling for 6 months. For the last 3 months of treatment, subjects were randomized into either a non-juggling group (n = 9) or a juggling therapy group (juggling group: n = 8). The juggling group gradually acquired juggling skills by practicing juggling beanbags (otedama in Japan) with both hands. The therapeutic effect was evaluated using scores of psychological testing (STAI: State and Trate Anxiety Inventry, POMS: Profile of Mood Status) and of ADL (FAI: Franchay Activity Index) collected before treatment, 3 months after treatment (before juggling therapy), and at the end of both treatments. RESULTS: After 6 months, an analysis of variance revealed that scores on the state anxiety, trait anxiety subscales of STAI and tension-anxiety (T-A) score of POMS were significantly lower in the juggling group than in the non-juggling group (p < 0.01). Depression, anger-hostility scores of POMS were improved more than non-jugglers. In the juggling group, activity scores on the vigor subscale of POMS and FAI score were significantly higher than those in the non juggling group (p < 0.01). Other mood scores of POMS did not differ between the two groups. CONCLUSION: These findings suggest that juggling therapy may be effective for the treatment of anxiety disorders.

11.
J Agric Food Chem ; 55(4): 1385-8, 2007 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-17243702

RESUMO

Nitrification inhibitory activity was found in root tissue extracts of Brachiaria humidicola, a tropical pasture grass. Two active inhibitory compounds were isolated by activity-guided fractionation, using recombinant Nitrosomonas europaea containing luxAB genes derived from the bioluminescent marine gram-negative bacterium Vibrio harveyi. The compounds were identified as methyl-p-coumarate and methyl ferulate, respectively. Their nitrification inhibitory properties were confirmed in chemically synthesized preparations of each. The IC50 values of chemically synthesized preparations were 19.5 and 4.4 microM, respectively. The ethyl, propyl, and butyl esters of p-coumaric and ferulic acids inhibited nitrification, whereas the free acid forms did not show inhibitory activity.


Assuntos
Nitrogênio/antagonistas & inibidores , Raízes de Plantas/química , Poaceae/química , Amônia/metabolismo , Ácidos Cumáricos/farmacologia , Metilação , Nitratos/metabolismo , Nitritos/metabolismo , Nitrogênio/metabolismo , Nitrosomonas/genética , Nitrosomonas/metabolismo , Propionatos , Vibrio/genética , Vibrio/metabolismo
12.
Phytother Res ; 21(3): 245-50, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17163581

RESUMO

Nimbolide, a triterpenoid extracted from the flowers of the neem tree (Azadirachta indica), was found to have antiproliferative activity against some cancer cell lines. Treatment of cells with 0.5-5.0 microm concentrations of nimbolide resulted in moderate to very strong growth inhibition in U937, HL-60, THP1 and B16 cell lines. Flow cytometric analysis of U937 cells showed that nimbolide treatment (1-2.5 microm) resulted in cell cycle disruption by decreasing the number of cells in G0/G1 phase, with initial increases in S and G2/M phases. Cells exposed to a higher dose of nimbolide for a longer period displayed a severely damaged DNA profile, resulting in a remarkable increase in the number of cells in the sub-G1 fraction, with a reciprocal decrease of cells in all phases. Quantification of the expression of phosphatidylserine in the outer cell membrane showed that doses of nimbolide higher than 0.4 microm exerted remarkable lethality, with over 60% of cells exhibiting apoptotic features after exposure to 1.2 microm nimbolide. The antiproliferative effect of nimbolide and its apoptosis-inducing property raise hope for its use in anticancer therapy by enhancing the effectiveness of cell cycle disruption.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Azadirachta , Limoninas/farmacologia , Fitoterapia , Antineoplásicos Fitogênicos/administração & dosagem , Antineoplásicos Fitogênicos/uso terapêutico , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Citometria de Fluxo , Humanos , Limoninas/administração & dosagem , Limoninas/uso terapêutico , Extratos Vegetais/administração & dosagem , Extratos Vegetais/farmacologia , Extratos Vegetais/uso terapêutico
13.
Planta Med ; 72(10): 917-23, 2006 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16858664

RESUMO

Nimbolide, a natural triterpenoid present in the edible parts of the neem tree ( Azadirachta indica), was found to be growth-inhibitory in human colon carcinoma HT-29 cells. Nimbolide treatment of cells at 2.5 - 10 microM resulted in moderate to very strong growth inhibition. Flow cytometric analysis of HT-29 cells showed that nimbolide treatment (2.5 microM, 12 h) caused a 6.5-fold increase in the number of cells (55.6 %) in the G2/M phase compared with the control cells (8.8 %). At 48 h, the cell population in the G2/M phase decreased to 18 %, while that in the G0/G1 phase increased to 52.3 %. Western blot analysis revealed that nimbolide-mediated G2/M arrest was accompanied by the up-regulation of p21, cyclin D2, Chk2; and down-regulation of cyclin A, cyclin E, Cdk2, Rad17. At G0/G1 cell cycle arrest, modulation in the expression of the cell cycle regulatory molecules was also observed. We found that nimbolide-induced growth inhibition and cell cycle arrest were not associated with cellular differentiation. Quantification of cells with respect to the expression of phosphatidylserine in the outer cell membrane showed an increase in apoptotic cells by about 13 % after 48 h of nimbolide treatment.


Assuntos
Antineoplásicos/farmacologia , Azadirachta/química , Ciclo Celular/efeitos dos fármacos , Inibidor de Quinase Dependente de Ciclina p21/genética , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Limoninas/farmacologia , Fosfatase Alcalina/genética , Fosfatase Alcalina/metabolismo , Antineoplásicos/química , Antineoplásicos/isolamento & purificação , Apoptose/efeitos dos fármacos , Diferenciação Celular , Proliferação de Células/efeitos dos fármacos , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Citotoxinas/química , Citotoxinas/isolamento & purificação , Citotoxinas/farmacologia , Avaliação Pré-Clínica de Medicamentos , Citometria de Fluxo , Células HT29 , Humanos , Limoninas/química , Limoninas/isolamento & purificação , Regulação para Cima
14.
Pharmacol Res ; 53(3): 293-302, 2006 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-16458014

RESUMO

The immunosuppressive drug cyclosporine A (CsA) has been used in both organ transplantation and the treatment of autoimmune disorders. However, the drug causes adverse effects in the kidney, liver and nervous system, characterized by cellular loss in the affected area. Apoptosis has been shown to play a role in CsA-induced cytotoxicity. Because permeabilization of the mitochondrial membrane is a common criterion in most apoptotic settings in vertebrate cells, here we evaluated whether CsA causes loss of mitochondrial function in the pathway leading to cellular cytotoxicity. We found that CsA caused a concentration- and time-dependent loss of cell viability in the U937 cell line. Treatment of cells at a dose of 10 microM CsA resulted in G0/G1 arrest with a concurrent decrease in the number of cells in the S and G2/M phases of the cell cycle. In mechanistic studies related to the loss of viability, treating cells with 10 microM CsA for 24 h resulted in both DNA fragmentation and an increase of annexin-V-positive cells. CsA treatment also increased activity of the cysteine protease caspase-3, decreased the mitochondrial membrane potential and induced the release of cytochrome c into the cytosol. Furthermore, CsA treatment increased the number of cells in the sub-G0/G1 peak, indicative of a reduction in DNA, although this increase was not observed when cells were pre-treated with a broad caspase inhibitor. In the study, we also found that a higher dose of CsA induces LDH release when the cells were incubated for a longer period. Taken together, these data suggest that the mode of cell death induced by CsA is dose- and time-dependent. Short-term incubation with lower doses of CsA arrests cell growth; this arrest overlaps with the occurrence of apoptosis and then with necrosis after longer treatment periods with higher doses of CsA.


Assuntos
Apoptose/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Ciclosporina/toxicidade , Imunossupressores/toxicidade , Mitocôndrias/efeitos dos fármacos , Ácido Aspártico/análogos & derivados , Ácido Aspártico/farmacologia , Caspase 3 , Inibidores de Caspase , Caspases/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Citocromos c/metabolismo , Relação Dose-Resposta a Droga , Humanos , Potenciais da Membrana , Mitocôndrias/enzimologia , Necrose , Inibidores de Proteases/farmacologia , Fatores de Tempo , Células U937
15.
Life Sci ; 78(19): 2226-33, 2006 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-16280138

RESUMO

Use of herbal remedies in the treatment of various diseases has a long tradition in Eastern medicine and the liver diseases are not an exception. In their use, lack of elucidation of mechanism(s) as well as randomized, placebo-controlled clinical trials has been a problem. Recently, we and others reported that inchin-ko-to (TJ-135), one of herbal remedies, suppressed hepatic fibrosis in animal models. In the course of clarifying the mechanism, we directed our focus on hepatic stellate cells (HSCs), playing a pivotal role in hepatic fibrosis, and found that rat HSCs cultured with TJ-135 changed their morphology to star-like configuration with thin, slender and dendritic processes with fewer stress fibers, which might be the features in apoptosis. In fact, TJ-135 induced HSC apoptosis in a time- and concentration-dependent manner as judged by the nuclear morphology, quantitation of cytoplasmic histone-associated DNA oligonucleosome fragments and caspase 3 activity. In HSCs treated with TJ-135, increased expression of p53 and decreased expression of Bcl-2 and phosphorylated Akt and Bad were determined. HSC apoptosis is shown to be involved in the mechanisms of spontaneous resolution of rat hepatic fibrosis and the agent which induces HSC apoptosis has been shown to reduce experimental hepatic fibrosis in rats. Thus, the induction of HSC apoptosis could be the mechanism how TJ-135 works on the resolution of hepatic fibrosis. Our current data may shed light on the novel effect of the herbal remedy.


Assuntos
Apoptose/efeitos dos fármacos , Medicamentos de Ervas Chinesas/farmacologia , Hepatócitos/efeitos dos fármacos , Animais , Caspase 3 , Caspases/metabolismo , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Núcleo Celular/patologia , Células Cultivadas , Citoesqueleto/efeitos dos fármacos , Citoesqueleto/patologia , Ensaio de Imunoadsorção Enzimática , Hepatócitos/citologia , Hepatócitos/metabolismo , Immunoblotting , Marcação In Situ das Extremidades Cortadas , Masculino , Proteínas Nucleares/metabolismo , Ratos , Ratos Sprague-Dawley
18.
Clin Biochem ; 38(11): 1023-6, 2005 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16098503

RESUMO

OBJECTIVES: Platelet release of alpha granule-derived CXC chemokines and dense granule-derived serotonin in plasma samples was evaluated. METHODS: Concentrations of the CXC chemokines beta-TG and PF4 were assayed by an enzyme immunoassay; serotonin was measured by an HPLC method. RESULTS: Beta-TG and PF4 were more easily released than serotonin by in vitro procedures. Use of the anti-platelet cocktail CTAD and preservation of the samples at 4 degrees C were necessary to accurately measure beta-TG and PF4, but not serotonin. CONCLUSIONS: Assaying serotonin may be useful for assessing platelet activation in vivo as a laboratory test because of facile preparation of plasma samples.


Assuntos
Plaquetas/metabolismo , Quimiocinas CXC/metabolismo , Fator Plaquetário 4/metabolismo , Serotonina/metabolismo , beta-Tromboglobulina/metabolismo , Adenosina/farmacologia , Adulto , Plaquetas/efeitos dos fármacos , Quimiocinas CXC/sangue , Ácido Cítrico/farmacologia , Dipiridamol/farmacologia , Ácido Edético/farmacologia , Humanos , Ativação Plaquetária/efeitos dos fármacos , Inibidores da Agregação Plaquetária/farmacologia , Serotonina/sangue , Teofilina/farmacologia
19.
J Biochem ; 138(1): 47-55, 2005 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16046448

RESUMO

Sphingosine 1-phosphate (Sph-1-P) is a bioactive lipid released from activated platelets and plays an important role in vascular biology. In this study, we investigated Sph-1-P-related metabolism in the blood vessel, mainly using radio-labeled Sph and Sph-1-P. Sph was metabolically stable in the plasma, while it was converted into Sph-1-P in the presence of activated platelets. When the mixture of Sph-1-P and plasma was fractionated on a gel-filtration column, all Sph-1-P co-eluted with protein fractions that coincide with lipoproteins and albumin by agarose gel electrophoresis. When evaluated by polyacrylamide gel electrophoresis, 7.2 +/- 3.8%, 53.3 +/- 6.4%, and 39.5 +/- 7.9% of the radioactivity of Sph-1-P added to plasma was recovered in the low-density lipoprotein (LDL), high-density lipoprotein (HDL), and albumin fractions, respectively. On the other hand, 5.2 +/- 3.2%, 38.4 +/- 5.5%, and 56.3 +/- 5.7% of the radioactivity of Sph-1-P converted from Sph in collagen-stimulated platelets and released into the plasma was recovered in the LDL, HDL, and albumin fractions, respectively. When Sph-1-P release from activated platelets was examined, a stronger response was observed in the presence of albumin than lipoproteins, suggesting efficient Sph-1-P extraction from platelets by albumin. Finally, Sph-1-P, which is stable in the plasma, was markedly degraded by an ectophosphatase activity in the presence of vascular endothelial cells or in whole blood. Although Sph-1-P is stable in the plasma, it is likely that the level of this bioactive lipid is dynamically controlled by various factors including release from platelets, distribution among plasma proteins, and degradation by ectophosphatase.


Assuntos
Plaquetas/química , Adulto , Endotélio Vascular/metabolismo , Humanos , Lipoproteínas/sangue , Lipoproteínas/metabolismo , Plasma/química , Sistemas do Segundo Mensageiro , Esfingolipídeos/metabolismo , Esfingosina/análogos & derivados , Esfingosina/metabolismo , Trombina/farmacologia , Veias Umbilicais/efeitos dos fármacos , Vanadatos/farmacologia
20.
Br J Pharmacol ; 145(2): 145-55, 2005 May.
Artigo em Inglês | MEDLINE | ID: mdl-15753952

RESUMO

1 Mahanine, a naturally occurring carbazole alkaloid in some Asian vegetables, has been shown to exhibit antimutagenicity, antimicrobial activity, cytotoxicity, and other biological properties. 2 In the present study, we investigated the effect of mahanine on the activation of the apoptotic pathway in human leukemia U937 cells. Various end points were used to screen for apoptosis: Morphological changes in cells, the relative numbers of viable and apoptotic cells; translocation of membrane bound phosphatidylserine and DNA analysis. 3 We found that mahanine-induced apoptosis in U937 cells involved activation of caspases, including caspase-3, release of cytochrome c into cytosol, loss of mitochondrial membrane permeability, and decreased levels of cellular ATP. 4 Pretreatment of cells with cyclosporine A, prior to/concomitant with exposure to mahanine, effectively prevented the deleterious effects of the alkaloid on cellular integrity and viability. 5 As mitochondrial permeability is known to be important in the regulation of cytochrome c release, our observations indicate that mitochondria are the principal target of mahanine. More specifically, we propose that mahanine causes the mitochondrial membranes to lose their permeability, resulting in caspase-3 activation and apoptosis.


Assuntos
Alcaloides/farmacologia , Antineoplásicos Fitogênicos/farmacologia , Apoptose , Carbazóis/farmacologia , Mitocôndrias/efeitos dos fármacos , Rutaceae , Caspase 3 , Caspases/metabolismo , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Ciclosporina/farmacologia , Citocromos c/metabolismo , Fragmentação do DNA , Ativação Enzimática , Humanos , Imunossupressores/farmacologia , Canais Iônicos/metabolismo , Mitocôndrias/fisiologia , Proteínas de Transporte da Membrana Mitocondrial , Poro de Transição de Permeabilidade Mitocondrial , Nucleossomos/efeitos dos fármacos , Nucleossomos/genética , Transporte Proteico , Células U937
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