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1.
Antioxidants (Basel) ; 13(2)2024 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-38397767

RESUMO

Taurine is ubiquitously distributed in mammalian tissues, with the highest levels in the brain, heart, and leukocytes. Taurine reacts with hypochlorous acid (HOCl) to produce taurine chloramine (Tau-Cl) via the myeloperoxidase (MPO) system. In this study, we elucidated the antioxidative and protective effects of Tau-Cl in astrocytes. Tau-Cl increased the expression and nuclear translocation of nuclear factor E2-related factor (Nrf2) and the expression of Nrf2-regulated antioxidant genes, including heme oxygenase 1 (HO-1). Nrf2 activity is negatively regulated by Kelch-like ECH-associated protein 1 (Keap1). Tau-Cl decreased the level of the reduced thiol groups of Keap1, resulting in the disruption of the Keap1-Nrf2 complex. Consequently, Tau-Cl rescued the H2O2-induced cell death by enhancing HO-1 expression and suppressing reactive oxygen species. In conclusion, Tau-Cl confers protective effects in astrocytes by disrupting the Keap1-Nrf2 complex, thereby promoting Nrf2 translocation to the nucleus, wherein it binds to the antioxidant response element (ARE) and accelerates the transcription of antioxidant genes. Therefore, in astrocytes, the activation of the Keap1-Nrf2-ARE pathway by Tau-Cl may increase antioxidants and anti-inflammatory mediators as well as other cytoprotective proteins, conferring protection against brain infection and injury.

2.
Int J Mol Sci ; 23(21)2022 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-36362318

RESUMO

Bone absorption is necessary for the maintenance of bone homeostasis. An osteoclast (OC) is a monocyte-macrophage lineage cell that absorbs bone tissue. Extracellular signal-regulated kinases (ERKs) are known to play important roles in regulating OC growth and differentiation. In this study, we examined specific downstream signal pathways affected by ERK inhibition during OC differentiation. Our results showed that the ERK inhibitors PD98059 and U0126 increased receptor activator of NF-κB ligand (RANKL)-induced OC differentiation in RAW 264.7 cells, implying a negative role in OC differentiation. This is supported by the effect of ERK2-specific small interfering RNA on increasing OC differentiation. In contrast to our findings regarding the RAW 264.7 cells, the ERK inhibitors attenuated the differentiation of bone marrow-derived cells into OCs. The ERK inhibitors significantly increased the phosphorylation of adenosine 5'-monophosphate-activated protein kinase (AMPK) but not the activation of p38 MAPK, Lyn, and mTOR. In addition, while the ERK inhibition increased the expression of the RANKL receptor RANK, it decreased the expression of negative mediators of OC differentiation, such as interferon regulatory factor-8, B-cell lymphoma 6, and interferon-γ. These dichotomous effects of ERK inhibition suggest that while ERKs may play positive roles in bone marrow-derived cells, ERKs may also play negative regulatory roles in RAW 264.7 cells. These data provide important information for drug development utilizing ERK inhibitors in OC-related disease treatment.


Assuntos
Proteínas Quinases Ativadas por AMP , Reabsorção Óssea , Camundongos , Animais , Proteínas Quinases Ativadas por AMP/metabolismo , Células RAW 264.7 , Ligante RANK/farmacologia , Ligante RANK/metabolismo , Osteoclastos/metabolismo , Osteogênese , Diferenciação Celular , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Reabsorção Óssea/metabolismo
3.
Adv Exp Med Biol ; 1370: 51-61, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35882781

RESUMO

Taurine, one of the most abundant amino acids, is ubiquitously distributed in mammalian tissues and is known to react with myeloperoxidase-derived hypochlorous acid (HOCl/OCl-) to produce taurine chloramine (Tau-Cl), which prevents inflammation by both suppressing pro-inflammatory mediators and increasing antioxidant levels. The migration of inflammatory cells, including neutrophils and macrophages, to infection sites is critical to the development of inflammation. In the present study, we investigated whether Tau-Cl suppresses the migration of inflammatory cells. Tau-Cl inhibited thioglycollate-induced leukocyte migration to the peritoneal cavity, as well as both fMLP-induced neutrophil migration and LPS-stimulated macrophage migration in a transwell system. Tau-Cl also inhibited LPS-induced actin polymerization, adhesion, and ERK phosphorylation in macrophages. Together, these findings suggest that Tau-Cl inhibits the infiltration of inflammatory cells into infection sites by inhibiting ERK activation, thereby preventing actin polymerization, and thus, the excessive infiltration of inflammatory cells, which can cause chronic inflammation.


Assuntos
Actinas , MAP Quinases Reguladas por Sinal Extracelular , Animais , Inflamação , Lipopolissacarídeos , Mamíferos/metabolismo , Neutrófilos/metabolismo , Óxido Nítrico/metabolismo , Polimerização , Taurina/análogos & derivados , Taurina/metabolismo , Taurina/farmacologia
4.
Cells ; 10(12)2021 12 07.
Artigo em Inglês | MEDLINE | ID: mdl-34943953

RESUMO

Carbon monoxide (CO) is generated by heme oxygenase (HO), and HO-1 is highly induced in monocytes and macrophages upon stimulation. Monocytes differentiate into macrophages, including pro-inflammatory (M1) and anti-inflammatory (M2) cells, in response to environmental signals. The present study investigated whether CO modulates macrophage differentiation and polarization, by applying the CO-releasing molecule-3 (CORM-3). Results showed that murine bone marrow cells are differentiated into macrophages by CORM-3 in the presence of macrophage colony-stimulating factor. CORM-3 increases expressions of macrophage markers, including F4/80 and CD11b, and alters the cell morphology into elongated spindle-shaped cells, which is a typical morphology of M2 cells. CORM-3 upregulates the expressions of genes and molecules involved in M2 polarization and M2 phenotype markers, such as STAT6, PPARγ, Ym1, Fizz1, arginase-1, and IL-10. However, exposure to CORM-3 inhibits the iNOS expression, suggesting that CO enhances macrophage differentiation and polarization toward M2. Increased HO-1 expression is observed in differentiated macrophages, and CORM-3 further increases this expression. Hemin, an HO-1 inducer, results in increased macrophage differentiation, whereas the HO-1 inhibitor zinc protoporphyrin IX inhibits differentiation. In addition, CORM-3 increases the proportion of macrophages in peritoneal exudate cells and enhances the expression of HO-1 and arginase-1 but inhibits iNOS. Taken together, these results suggest that the abundantly produced CO in activated macrophages enhances proliferation, differentiation, and polarization toward M2. It will probably help clear apoptotic cells, resolve inflammation, and promote wound healing and tissue remodeling.


Assuntos
Arginase/genética , Monóxido de Carbono/metabolismo , Diferenciação Celular/genética , Heme Oxigenase-1/genética , Macrófagos/efeitos dos fármacos , Animais , Antígeno CD11b/genética , Monóxido de Carbono/efeitos adversos , Polaridade Celular/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Macrófagos/metabolismo , Camundongos , Monócitos/efeitos dos fármacos , Óxido Nítrico Sintase Tipo II/genética , Compostos Organometálicos/farmacologia , PPAR gama/genética , Fenótipo , Fator de Transcrição STAT6/genética
5.
Antioxidants (Basel) ; 10(3)2021 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-33801397

RESUMO

Taurine is ubiquitously distributed in mammalian tissues and is highly concentrated in the heart, brain, and leukocytes. Taurine exerts neuroprotective effects in various central nervous system diseases and can suppress infarct formation in stroke. Taurine reacts with myeloperoxidase (MPO)-derived hypochlorous acid (HOCl) to produce taurine chloramine (Tau-Cl). We investigated the neuroprotective effects of taurine using a rat middle cerebral artery occlusion (MCAO) model and BV2 microglial cells. Although intranasal administration of taurine (0.5 mg/kg) had no protective effects, the same dose of Tau-Cl significantly reduced infarct volume and ameliorated neurological deficits and promoted motor function, indicating a robust neuroprotective effect of Tau-Cl. There was neutrophil infiltration in the post-MCAO brains, and the MPO produced by infiltrating neutrophils might be involved in the taurine to Tau-Cl conversion. Tau-Cl significantly increased the levels of antioxidant enzymes glutamate-cysteine ligase, heme oxygenase-1, NADPH:quinone oxidoreductase 1, and peroxiredoxin-1 in BV2 cells, whereas taurine slightly increased some of them. Antioxidant enzyme levels were increased in the post-MCAO brains, and Tau-Cl further increased the level of MCAO-induced antioxidant enzymes. These results suggest that the neutrophils infiltrate the area of ischemic injury area, where taurine is converted to Tau-Cl, thus protecting from brain injury by scavenging toxic HOCl and increasing antioxidant enzyme expression.

6.
Amino Acids ; 52(8): 1191-1199, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32865666

RESUMO

Taurine is a free amino acid rich in neutrophils, and neutrophils play an important role in the forefront defense against infection. Upon neutrophil activation, taurine reacts with hypochlorous acid (HOCl/OCl-) produced by the myeloperoxidase (MPO) system and gets converted to taurine chloramine (Tau-Cl). Neutrophils have three types of granules, of which the primary granule MPO, secondary granule lactoferrin, and tertiary granule matrix metalloproteinase (MMP)-9 are released into the extracellular space by a process called degranulation. MPO produces hypochlorous acid to kill microorganisms, and the released MPO forms neutrophil extracellular traps (NETs) with released chromatin. Excessive secretion of MPO causes oxidative damage to the surrounding tissues. Lactoferrin exerts antioxidant activity, prevents pro-inflammatory pathway activation, sepsis, and tissue damages, and delays neutrophil apoptosis. Our experimental results show that neutrophils released small amount of granules in an inactive state, and phorbol 12-myristate 13-acetate (PMA) and N-formyl-methionine-leucyl-phenylalanine induced neutrophil degranulation. Tau-Cl inhibited the PMA-induced degranulation of MPO and formation of NETs. While Tau-Cl increased the degranulation of lactoferrin, it had no effect on MMP-9 degranulation. MPO negatively regulated the production of macrophage inflammatory protein (MIP)-2, which stimulates the degranulation and migration of neutrophils. Tau-Cl abrogated MIP-2 expression, suggestive of its inhibitory effect on MPO release. The increase in the intracellular level of MPO may negatively regulates MIP-2 expression, thereby contributing to the further regulation of neutrophil degranulation and migration. Here, we suggest that Tau-Cl selectively inhibits MPO degranulation and stimulates lactoferrin degranulation from neutrophils, thereby protecting inflamed tissues from oxidative damage induced by excessively released MPO.


Assuntos
Degranulação Celular/fisiologia , Lactoferrina/metabolismo , Neutrófilos/metabolismo , Peroxidase/metabolismo , Taurina/análogos & derivados , Animais , Degranulação Celular/efeitos dos fármacos , Sobrevivência Celular , Armadilhas Extracelulares/metabolismo , Metaloproteinase 9 da Matriz/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Taurina/farmacologia , Taurina/fisiologia , Acetato de Tetradecanoilforbol/metabolismo
7.
Nutrients ; 12(8)2020 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-32806557

RESUMO

Postmenopausal osteoporosis is a common disorder resulting from increased osteoclastic activity. To determine the effect of Panax ginseng on postmenopausal osteoporosis, ovariectomized (OVX) mice were treated with 500 mg/kg/day P. ginseng extract (Pg) alone or in combination with hot water extract of Brassica oleracea (Bo) daily for 10 weeks, and the effect of the treatments on OVX-induced bone loss was examined. Bone weight, bone mineral density (BMD), osteoclast (OC) formation, OC marker expression, and biochemical parameters in blood were determined. OVX significantly increased body weight and decreased bone weight compared with those in the Sham group (p < 0.01). Pg or Bo alone did not affect OVX-induced bone loss, but a combination of Pg and Bo (Pg:Bo) recovered bone weight. The bones of OVX mice showed lower BMD than that of Sham mice, and the Pg:Bo = 3:1 restored the decreased BMD. Single treatment with Pg or Bo did not alter OC formation; however, the Pg:Bo = 3:1 inhibited OC formation. In addition, Pg and Bo lowered the OVX-induced elevation in blood glucose level. Thus, we suggest that Pg in combination with proper materials, such as Bo, might be a potential candidate treatment with minimal side effects protect against postmenopausal osteoporosis.


Assuntos
Densidade Óssea/efeitos dos fármacos , Brassica , Osteoporose Pós-Menopausa/prevenção & controle , Panax , Extratos Vegetais/administração & dosagem , Animais , Modelos Animais de Doenças , Quimioterapia Combinada , Feminino , Humanos , Camundongos , Osteoclastos/efeitos dos fármacos , Osteoporose Pós-Menopausa/etiologia , Ovariectomia
8.
Sci Rep ; 10(1): 7024, 2020 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-32341385

RESUMO

Vav1 regulates Rac activation as a hematopoietic-specific Rho/Rac-family guanine nucleotide exchange factor. Rac is a subfamily of Rho GTPases that regulates the bone-resorbing capacity of osteoclasts (OCs). In this study, we show that hematopoietic-specific Rac2 and Vav1 play opposing roles by enhancing or attenuating OC differentiation, respectively. This was demonstrated by higher and lower bone density in the femurs from Rac2-deficient (Rac2-/-) and Vav1-deficient (Vav1-/-) mice, respectively, compared to the wild-type (WT) mice. Accordingly, Rac2-/- cells displayed low numbers of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells (41%) compared to WT cells, whereas, Vav1-/- cells showed high TRAP-positive cell numbers (150%), and the double-knockout Rac2-/-Vav1-/- mice nullified the effects on OC numbers achieved by the individual knockouts. These reciprocal roles of Rac2 and Vav1 in OC differentiation were confirmed by reduced and increased levels of OC-specific markers, such as TRAP, calcitonin receptor, cathepsin K, and DC-STAMP in the Rac2-/- and Vav1-/- OCs, respectively. Our findings of decrease and increase in actin ring formation and αvß3 integrin-mediated adhesion in Rac2-/- and Vav1-/- mice, respectively, suggest that Vav1 and its downstream GTPase, Rac2, may counteract to fine-tune OC differentiation and bone resorption.


Assuntos
Diferenciação Celular/fisiologia , Hematopoese , Osteoclastos/citologia , Proteínas Proto-Oncogênicas c-vav/fisiologia , Proteínas rac de Ligação ao GTP/fisiologia , Animais , Camundongos Knockout , Osteoclastos/metabolismo
9.
Free Radic Res ; 54(11-12): 894-905, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32183593

RESUMO

Osteoclasts (OCs) are multinucleated cells that are phylogenetically evolved from monocyte-macrophage lineage and are essential for skeletal coupling processes. During bone development, bone formation by osteoblasts and bone resorption by OCs are tightly coupled and are involved in bone homeostasis. Therefore, it is essential to understand the mechanisms that regulate OC differentiation in order to develop effective therapeutics for the treatment of OC-associated diseases. This study aimed to determine the molecular mechanisms regulating OC differentiation. The mitogen-activated protein kinases and extracellular signal-regulated kinase (ERK) are recognised to be crucial factors regulating OC differentiation and activation. RAW 264.7 cells were differentiated into OCs in the presence of RANKL and were treated with inhibitors of several signal pathways. Although PD98059 is an ERK inhibitor, it inhibited the phosphorylation of ERK, JNK, Akt, and Src kinase. PD98059 increased OC differentiation and expression of OC markers, such as TRAP, calcitonin receptor, and cathepsin K, and increased the expression of NFATc1. Moreover, it also increased the expression of glutamate-cysteine ligase and production of glutathione (GSH). Thus, we examined the involvement of GSH in OC differentiation and observed that GSH treatment alone increased the OC numbers and cotreatment with PD98059 further enhanced OC differentiation. Our results suggested that inhibition of the ERK pathway may promote OC differentiation via upregulation of GSH. These findings reveal that ERK and GSH modulate the signal pathway necessary for OC differentiation, and this may form the basis of a new therapeutic strategy for treating OC-related diseases.


Assuntos
Glutationa/metabolismo , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Osteoclastos/efeitos dos fármacos , Ligante RANK/farmacologia , Animais , Diferenciação Celular/efeitos dos fármacos , Glutationa/biossíntese , Humanos , Camundongos , Células RAW 264.7 , Proteínas Recombinantes/farmacologia , Fatores de Transcrição , Regulação para Cima
10.
Adv Exp Med Biol ; 1155: 61-70, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31468386

RESUMO

Taurine is an abundant sulfur-containing amino acid in myeloid cells. It undergoes halogenation in activated phagocytes and is converted to taurine chloramine (TauCl) and taurine bromamine. Bone homeostasis is mediated by the balance between bone-forming osteoblasts and bone-resorbing osteoclasts. Osteoclasts are bone-resorbing multinucleated cells differentiated from monocyte/macrophage precursor cells in response to receptor activator of NF-κB ligand (RANKL). In this study, we investigated the effect of TauCl on RANKL-induced osteoclastogenesis from RAW 264.7 macrophages. TauCl inhibited the formation of multi-nucleated osteoclast and the activity of tartrate-resistant acid phosphatase (TRAP). TauCl decreased the mRNA expression of osteoclast markers, such as TRAP, cathepsin K, and calcitonin receptor. TauCl also inhibited expression of the transcription factors, c-Fos and nuclear factor of activated T cells, which are important for osteoclast differentiation. These results suggest that TauCl might be used as a therapeutic agent to treat bone diseases associated with excessive bone resorption.


Assuntos
Diferenciação Celular , Osteoclastos/efeitos dos fármacos , Taurina/análogos & derivados , Animais , Camundongos , Ligante RANK/fisiologia , Células RAW 264.7 , Transdução de Sinais , Fosfatase Ácida Resistente a Tartarato/fisiologia , Taurina/farmacologia , Fatores de Transcrição/fisiologia
11.
BMB Rep ; 52(11): 659-664, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31072447

RESUMO

Vav1 is a Rho/Rac guanine nucleotide exchange factor primarily expressed in hematopoietic cells. In this study, we investigated the potential role of Vav1 in osteoclast (OC) differentiation by comparing the ability of bone marrow mononuclear cells (BMMCs) obtained from Vav1-deficient (Vav1-/-) and wild-type (WT) mice to differentiate into mature OCs upon stimulation with macrophage colony stimulating factor and receptor activator of nuclear kappa B ligand in vitro. Our results suggested that Vav1 deficiency promoted the differentiation of BMMCs into OCs, as indicated by the increased expression of tartrate-resistant acid phosphatase, cathepsin K, and calcitonin receptor. Therefore, Vav1 may play a negative role in OC differentiation. This hypothesis was supported by the observation of more OCs in the femurs of Vav1-/- mice than in WT mice. Furthermore, the bone status of Vav1-/- mice was analyzed in situ and the femurs of Vav1-/- mice appeared abnormal, with poor bone density and fewer number of trabeculae. In addition, Vav1-deficient OCs showed stronger adhesion to vitronectin, an αvß3 integrin ligand important in bone resorption. Thus, Vav1 may inhibit OC differentiation and protect against bone resorption. [BMB Reports 2019; 52(11): 659-664].


Assuntos
Osteoclastos/metabolismo , Proteínas Proto-Oncogênicas c-vav/metabolismo , Animais , Células da Medula Óssea/metabolismo , Reabsorção Óssea/metabolismo , Osso e Ossos/metabolismo , Diferenciação Celular/fisiologia , Integrina alfaVbeta3/metabolismo , Fator Estimulador de Colônias de Macrófagos/metabolismo , Fator Estimulador de Colônias de Macrófagos/farmacologia , Masculino , Glicoproteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Osteoclastos/citologia , Proteínas Proto-Oncogênicas c-vav/genética , Proteínas Proto-Oncogênicas c-vav/fisiologia , Ligante RANK/metabolismo , Ligante RANK/fisiologia , Receptor Ativador de Fator Nuclear kappa-B/metabolismo , Fosfatase Ácida Resistente a Tartarato
12.
Adv Exp Med Biol ; 975: 675-684, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28849491

RESUMO

Amino acids (AAs) are essential for protein synthesis, neurotransmission and macro molecule biosynthesis. Ala, Gln, Gly, Lys, Val and taurine (Tau) are the most abundant free AAs in mammals, and some of these react with hypochlorite (HOCl/OCl-) produced by myeloperoxidase in activated phagocytes to form N-chloroamino acids (NCAA). In this study, we reacted 20 AAs and Tau with sodium hypochlorite (NaOCl), then classified the products into five types (I-V) based on the change in their absorbance. Type I AAs (Ala, Arg, Gln, Gly, Ile, Lys, Phe, Ser, Tau, Thr and Val) generated a typical monochloramine peak at 252 nm, while Type II AAs (Asn and Tyr) and Type III AAs (Glu and Leu) produced peaks at 275 nm and 225 nm, respectively. The Type IV AAs (His, Met and Trp) did not show any distinct absorption peak, and Type V AAs (Asp, Cys and Pro) did not appear to react with NaOCl. The ArgCl and TauCl were stable, while GlnCl, GlyCl, IleCl, LysCl, PheCl and ValCl were less stable and AlaCl, SerCl and ThrCl were the least stable. Tau is the most abundant non-proteinogenic free AA in cellular fluid and has many physiological functions in the nervous, cardiovascular, renal and immune systems. Tau reacts with HOCl to form TauCl, which inhibits the production of proinflammatory mediators such as superoxide, nitric oxide (NO) and interleukins, while increasing the antioxidant proteins in macrophages. We determined the effects of Type I NCAA on cell viability, NO and TNF-α production in LPS-activated RAW 264.7 cells. All Type I NCAA showed dose-dependent cytotoxicity and inhibited LPS-induced NO production. However, only GlnCl, GlyCl, IleCl, LysCl, SerCl and TauCl inhibited LPS-induced TNF-α production. In summary, Type I NCAA showed dose-dependent cytotoxicity and inhibited NO production, while their effects on TNF-α varied. Our results suggest that Type I NCAA may serve as biological regulators similar to TauCl during inflammation.


Assuntos
Anti-Inflamatórios/metabolismo , Taurina/metabolismo , Aminoácidos/metabolismo , Animais , Anti-Inflamatórios/farmacologia , Ácido Hipocloroso/metabolismo , Lipopolissacarídeos/toxicidade , Camundongos , Células RAW 264.7 , Taurina/farmacologia
13.
Sci Rep ; 6: 38014, 2016 11 29.
Artigo em Inglês | MEDLINE | ID: mdl-27897222

RESUMO

Bone-marrow derived monocyte-macrophages (BMMs) differentiate into osteoclasts by M-CSF along subsequent RANKL stimulation possibly in collaboration with many other unknown cytokines released by pre- or mature osteoblasts. The differentiation process requires receptor activator of nuclear factor kappa-B ligand (RANKL)/RANK signaling and reactive oxygen species (ROS) such as superoxide anion (O2•-). Gp91phox, a plasma membrane subunit of NADPH oxidase (Nox), is constitutively expressed in BMMs and plays a major role in superoxide anion production. In this study, we found that mice deficient in gp91phox (gp91phox-/-) showed defects in osteoclast differentiation. Femurs of these mice produced osteoclasts at about 70% of the levels seen in femurs from wild-type mice, and accordingly exhibited excessive bone density. This abnormal bone growth in the femurs of gp91phox-/- mice resulted from impaired osteoclast differentiation. In addition, gp91phox-/- mice were defective for RANKL-induced expression of nuclear factor of activated T cells c1 (NFATc1). However, H2O2 treatment compensated for gp91phox deficiency in BMMs, almost completely rescuing osteoclast differentiation. Treating wild-type BMMs with antioxidants and superoxide inhibitors resulted in a differentiation defect resembling the phenotype of gp91phox-/- BMMs. Therefore, our results demonstrate that gp91phox-derived superoxide is important for promoting efficient osteoclast differentiation by inducing NFATc1 as a downstream signaling mediator of RANK.


Assuntos
Reabsorção Óssea/etiologia , Diferenciação Celular , Fatores de Transcrição NFATC/metabolismo , Osteoclastos/citologia , Ligante RANK/metabolismo , Receptores Imunológicos/fisiologia , Animais , Reabsorção Óssea/metabolismo , Reabsorção Óssea/patologia , Células Cultivadas , Macrófagos/citologia , Macrófagos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fatores de Transcrição NFATC/genética , Osteoclastos/metabolismo , Osteogênese/fisiologia , Ligante RANK/genética , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais , Regulação para Cima
14.
Plant Physiol Biochem ; 109: 525-535, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27835850

RESUMO

To investigate the role of ω-3 fatty acid (FA) desaturase (FAD8) during cold acclimation in higher plants, we characterized three independent T-DNA insertional knock-out mutants of OsFAD8 from rice (Oryza sativa L.). At room temperature (28 °C), osfad8 plants exhibited significant alterations in fatty acid (FA) unsaturation for all four investigated plastidic lipid classes. During a 5-d acclimation period at 4 °C, further changes in FA unsaturation in both wild-type (WT) and mutant plants varied according to the type of lipid. We also monitored the fluidity of the thylakoid membrane using a threshold temperature to represent the change in fluorescence. The values were altered significantly by both FAD8 mutation and cold acclimation, suggesting that factors other than FAD8 are involved in C18 FA unsaturation and fluctuations in membrane fluidity. Similarly, significant changes were noted for both the mutant and WT samples in terms of their FA compositions as well as activities related to photosystem (PS) I, PSII, and photoprotection. This included the development of non-photochemical quenching and increased zeaxanthin accumulation. Despite the relatively small changes in FA composition during cold acclimation, cold-inducible FAD8 knock-out mutants displayed strong differences in photoprotective activities and a further drop in membrane fluidity. The mutants were more sensitive than WT to short-term low-temperature stress that resulted in increased production of reactive oxygen species after 5 d of chilling. Taken together, our findings suggest that FA unsaturation by OsFAD8 is crucial for the acclimation of higher plants to low-temperature stress.


Assuntos
Ácidos Graxos Dessaturases/deficiência , Ácidos Graxos Dessaturases/genética , Oryza/genética , Oryza/fisiologia , Proteínas de Plantas/genética , Aclimatação/genética , Aclimatação/fisiologia , Clima Frio , Ácidos Graxos Insaturados/química , Ácidos Graxos Insaturados/metabolismo , Técnicas de Inativação de Genes , Genes de Plantas , Fluidez de Membrana , Mutação , Oryza/enzimologia , Complexo de Proteína do Fotossistema I/metabolismo , Complexo de Proteína do Fotossistema II/metabolismo , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Espécies Reativas de Oxigênio/metabolismo
16.
Plant Cell Rep ; 34(7): 1127-38, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25689889

RESUMO

KEY MESSAGE: AtSFT12, an Arabidopsis Qc-SNARE protein, is localized to Golgi organelles and is involved in salt and osmotic stress responses via accumulation of Na (+) in vacuoles. To reduce the detrimental effects of environmental stresses, plants have evolved many defense mechanisms. Here, we identified an Arabidopsis Qc-SNARE gene, AtSFT12, involved in salt and osmotic stress responses using an activation-tagging method. Both activation-tagged plants and overexpressing transgenic plants (OXs) of the AtSFT12 gene were tolerant to high concentrations of NaCl, LiCl, and mannitol, whereas loss-of-function mutants were sensitive to NaCl, LiCl, and mannitol. AtSFT12 transcription increased under NaCl, ABA, cold, and mannitol stresses but not MV treatment. GFP-fusion AtSFT12 protein was juxtaposed with Golgi marker, implying that its function is associated with Golgi-mediated transport. Quantitative measurement of Na(+) using induced coupled plasma atomic emission spectroscopy revealed that AtSFT12 OXs accumulated significantly more Na(+) than WT plants. In addition, Na(+)-dependent fluorescence analysis of Sodium Green showed comparatively higher Na(+) accumulation in vacuoles of AtSFT12 OX cells than in those of WT plant cells after salt treatments. Taken together, our findings suggest that AtSTF12, a Golgi Qc-SNARE protein, plays an important role in salt and osmotic stress responses and functions in the salt stress response via sequestration of Na(+) in vacuoles.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/fisiologia , Osmose/efeitos dos fármacos , Proteínas Qc-SNARE/genética , Cloreto de Sódio/farmacologia , Sódio/metabolismo , Estresse Fisiológico/genética , Vacúolos/metabolismo , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Genes de Plantas , Complexo de Golgi/efeitos dos fármacos , Complexo de Golgi/metabolismo , Mutação/genética , Especificidade de Órgãos/efeitos dos fármacos , Especificidade de Órgãos/genética , Plantas Geneticamente Modificadas , Transporte Proteico/efeitos dos fármacos , Proteínas Qc-SNARE/metabolismo , Estresse Fisiológico/efeitos dos fármacos , Frações Subcelulares/efeitos dos fármacos , Frações Subcelulares/metabolismo , Fatores de Tempo , Transcrição Gênica/efeitos dos fármacos , Vacúolos/efeitos dos fármacos
17.
Adv Exp Med Biol ; 775: 259-67, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23392941

RESUMO

Taurine chloramine (TauCl) is produced from taurine by the -myeloperoxidase-halide system in activated neutrophils via a stoichiometric reaction between taurine and HOCl. TauCl has been shown to provide cytoprotection against inflammatory tissue injury by inhibiting the overproduction of inflammatory mediators and also by increasing the expression of antioxidant enzymes that are regulated by nuclear factor E2-related factor 2 in murine macrophages. In this study, primary murine macrophages were prepared after either by injection of 3% thioglycolate into mouse peritoneal cavity or by differentiation of the isolated bone marrow cells. TauCl increased HO-1, Prx-1, and Trx-1 expression in murine primary -macrophages. Also, when TauCl was injected in combination with 3% thioglycolate, HO-1 expression in the peritoneal macrophages was increased. Our results suggest that TauCl plays a protective role against cytotoxicity of oxidative stress in macrophages by increasing the expression of antioxidant enzymes in vivo.


Assuntos
Antioxidantes/metabolismo , Macrófagos Peritoneais/efeitos dos fármacos , Macrófagos Peritoneais/enzimologia , Fator 2 Relacionado a NF-E2/metabolismo , Taurina/análogos & derivados , Animais , Células da Medula Óssea/citologia , Heme Oxigenase-1/metabolismo , Injeções Intraperitoneais , Camundongos , Camundongos Endogâmicos C57BL , Taurina/administração & dosagem , Taurina/farmacologia
18.
Acta Trop ; 122(1): 59-63, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22172595

RESUMO

Health education has been shown to be effective in slowing the spread of the disease, infectious disease in particular. To evaluate the impact of health education on the prevalence and pattern of new infection of enterobiasis, children from 6 kindergartens in Ulsan city, South Korea, were recruited after undergoing a screening for enterobiasis, and then divided into three groups, including group medication (GM), education (Edu), and control group. All children in GM group received medical treatment with 500 mg albendazole twice, with 15 days interval. In the Edu group, only children diagnosed positive for Enterobius vermicularis eggs received medical treatment with 500 mg albendazole twice, with 15 days interval and all parents in the group received brochures providing information about enterobiasis. In the control group, only children diagnosed positive for E. vermicularis eggs received medical treatment with 500 mg albendazole twice, with 15 days interval, and no information about enterobiasis was provided to parents. Two post-treatment examinations were performed at three and six months after treatment. The infection rate in the GM group was dramatically decreased at 3 months, and this rate was almost the same as at 6 months after treatment. Infection rate of children in the Edu group was shown to drop from 9.9% to 3.0% at 3 months, and to 2.7% at 6 months after treatment; however, the infection rate in the control group continued to be higher than in the other two groups at both 3 and 6 months, with smaller change at 3 months compared to the other two groups. In addition, both new infection and re-infection cases in the Edu group were fewer, compared to those in the control group. In conclusion, although GM is the best method for eradication of enterobiasis, providing health information about enterobiasis to parents could reduce the prevalence, as well as the rate of new infection or re-infection with E. vermicularis in their children.


Assuntos
Enterobíase/epidemiologia , Enterobíase/prevenção & controle , Enterobius/isolamento & purificação , Educação em Saúde/métodos , Albendazol/administração & dosagem , Animais , Anti-Helmínticos/administração & dosagem , Criança , Pré-Escolar , Enterobíase/tratamento farmacológico , Enterobíase/parasitologia , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Pesquisa sobre Serviços de Saúde , Humanos , Masculino , Prevalência , República da Coreia/epidemiologia , Resultado do Tratamento
19.
J Plant Physiol ; 168(2): 140-7, 2011 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-20633954

RESUMO

The plant hormone, abscisic acid (ABA), is a main signal transducer that confers abiotic stress tolerance to plants. Although the pathway of ABA production and the genes catalyzing its biosynthesis are largely defined, the regulatory mechanism of ABA biosynthesis in response to abiotic stress remains much unknown. In this study, to identify upstream genes regulating ABA biosynthesis involved in abiotic stress signal transduction, Arabidopsis thaliana mutants with altered promoter activity of 9-cis-epoxycarotenoid dioxygenase 3 (NCED3), a key gene in ABA biosynthesis, were identified and characterized. Among selected mutants, lenc1 (for low expression of NCED3 1) after dehydration treatment had lower AtNCED3 promoter activity compared with wild type. lenc1 mutation is recessive and is located on chromosome 4. Expression analysis of AtNCED3 and quantification of ABA levels showed that both the AtNCED3 transcripts and the endogenous ABA in lenc1 were less abundant than in wild type under dehydration treatments. The lenc1 was hypersensitive to methyl viologen (MV), LiCl, NaCl and high light. The aerial part of lenc1 lost water faster than wild type possibly due to a larger stomata opening. Our results suggest LENC1 might act as a positive regulator in AtNCED3 gene expression under osmotic stress.


Assuntos
Ácido Abscísico/metabolismo , Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Dioxigenases/metabolismo , Proteínas de Plantas/metabolismo , Arabidopsis/efeitos dos fármacos , Arabidopsis/enzimologia , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Dioxigenases/genética , Cloreto de Lítio/toxicidade , Pressão Osmótica/efeitos dos fármacos , Proteínas de Plantas/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa
20.
Biochem Biophys Res Commun ; 380(3): 597-602, 2009 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-19285007

RESUMO

Excessive light can be harmful to photosynthetic apparatus since it causes photoinhibition and photooxidation, and plants often encounter hypoxic or anoxic environments when they become submerged by heavy rain or an ensuing flood. In this study, Oryza sativa Differentially Expressed Genes (OsDEGs) from rice under photooxidation and anoxia conditions were isolated using DD-PCR. Among them, OsDEG10 is predicted to encode a small RNA-binding protein (RBP) and the transcript levels of OsDEG10 strongly increased under most of abiotic stress treatments such as high light, anoxia, NaCl, ABA, MV and cold. However, the transcript levels of two rice OsDEG10 homologs were not changed under those treatments. OsDEG10 RNAi transgenic plants were more sensitive to high light and cold stresses compared to wild-type plants. Our results suggest that OsDEG10 is a small RBP involved in the response to various abiotic stresses.


Assuntos
Oryza/fisiologia , Proteínas de Plantas/metabolismo , Proteínas de Ligação a RNA/metabolismo , Estresse Fisiológico , Sequência de Aminoácidos , Anaerobiose , Temperatura Baixa , Secas , Luz , Dados de Sequência Molecular , Oryza/genética , Oryza/metabolismo , Oryza/efeitos da radiação , Pressão Osmótica , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Plantas Geneticamente Modificadas/fisiologia , Proteínas de Ligação a RNA/genética , Transdução de Sinais , Estresse Fisiológico/genética , Transcrição Gênica , Regulação para Cima
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