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PURPOSE: To investigate the changes in ocular higher-order aberrations (HOA) after trabeculectomy using mitomycin-C (MMC). METHODS: We retrospectively reviewed data for 63 eyes from 63 glaucoma patients who had undergone MMC augmented trabeculectomy. We measured intraocular pressure (IOP), refractive errors, anterior chamber depth (ACD), and HOA before surgery and 1, 2, and 4 weeks postoperatively. The patients were divided into two groups on the basis of preoperative lens status: phakic and pseudophakic group. We used a paired t test to compare preoperative and postoperative HOA values. Regression analysis was used to compare higher-order total (HOT) change and factors including ACD and age. RESULTS: For entire eye aberrations, coma-like and total HOT were significantly increased postoperatively at 1 week (P = 0.029, P = 0.005, respectively), but not after 2 or 4 weeks in the phakic group and were not significant at any time in the pseudophakic group. Corneal HOA were significantly increased postoperatively after 1, 2 weeks, but not after 4 weeks in the phakic group and were not significant in the pseudophakic group. For internal optics aberrations, HOA were significantly increased postoperatively at 1, 2, and 4 weeks in the phakic group, but were not significant at any time in the pseudophakic group. However, HOT aberration change showed no correlation with age, ACD, IOP change in either group. CONCLUSION: Following trabeculectomy, HOA changes were significantly increased postoperatively at 1, 2 weeks in the phakic group. Therefore, visual complaint-related HOA changes after trabeculectomy may be more profound in phakic patients.
Assuntos
Córnea/patologia , Topografia da Córnea/métodos , Aberrações de Frente de Onda da Córnea/etiologia , Glaucoma de Ângulo Aberto/cirurgia , Mitomicina/farmacologia , Refração Ocular/fisiologia , Trabeculectomia/métodos , Antibióticos Antineoplásicos/farmacologia , Aberrações de Frente de Onda da Córnea/diagnóstico , Aberrações de Frente de Onda da Córnea/fisiopatologia , Feminino , Seguimentos , Glaucoma de Ângulo Aberto/fisiopatologia , Humanos , Pressão Intraocular , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias , Estudos Retrospectivos , Fatores de Tempo , Resultado do TratamentoRESUMO
Programmed cell death 5 (PDCD5) plays a crucial role in TP53-mediated apoptosis, but the regulatory mechanism of PDCD5 itself during apoptosis remains obscure. We identified YY1-associated factor 2 (YAF2) as a novel PDCD5-interacting protein in a yeast two-hybrid screen for PDCD5-interacting proteins. We found that YY1-associated factor 2 (YAF2) binds to and increases PDCD5 stability by inhibiting the ubiquitin-dependent proteosomal degradation pathway. However, knocking-down of YAF2 diminishes the levels of PDCD5 protein but not the levels of PDCD5 mRNA. Upon genotoxic stress response, YAF2 promotes TP53 activation via association with PDCD5. Strikingly, YAF2 failed to promote TP53 activation in the deletion of PDCD5, whereas restoration of wild-type PDCD5WT efficiently reversed the ineffectiveness of YAF2 on TP53 activation. Conversely, PDCD5 efficiently overcame the knockdown effect of YAF2 on ET-induced TP53 activation. Finally, impaired apoptosis upon PDCD5 ablation was substantially rescued by restoration of PDCD5WT but not YAF2-interacting defective PDCD5E4D nor TP53-interacting defective PDCD5E16D mutant. Our findings uncovered an apoptotic signaling cascade linking YAF2, PDCD5, and TP53 during genotoxic stress responses.
Assuntos
Proteínas Reguladoras de Apoptose/metabolismo , Dano ao DNA , Proteínas Musculares/metabolismo , Proteínas de Neoplasias/metabolismo , Proteínas Repressoras/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Animais , Linhagem Celular Tumoral , Humanos , Leupeptinas/farmacologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Modelos Biológicos , Ligação Proteica , Multimerização Proteica , Estabilidade Proteica/efeitos dos fármacos , UbiquitinaçãoRESUMO
Hybrid assemblies consisting of metal nanoparticles (NPs) and fluorophores are quite interesting because the intrinsic properties of fluorophores can be engineered in the assembled structure. In this regard, we utilized the self-segregation properties of block copolymer micelles to organize metal NPs and fluorophores simultaneously in a specific arrangement. From the viewpoint of assembly methods, we first encapsulated Au NPs in the PS cores of polystyrene-block-poly(acrylic acid) (PS-PAA) micelles. Then, positively charged fluorescent dyes of rhodamine 123 (R123) were bound to the negatively charged PAA coronas by electrostatic interactions. Since carboxylic acid in the PAA block is a weak acid, the degree of R123 binding to PS-PAA micelles can be adjusted by varying the pH of the solution. Therefore, by changing the pH, we were able to control the assembly and disassembly of R123 molecules to PS-PAA micelles and the corresponding change in the fluorescence signal.
RESUMO
AIMS/HYPOTHESIS: Thioredoxin-interacting protein (TXNIP) is upregulated in the hyperglycaemic state and represses glucose uptake, resulting in imbalanced glucose homeostasis. In this study, we propose a mechanism of how TXNIP impairs hepatic glucose tolerance at the transcriptional level. METHODS: We administered adenoviral Txnip (Ad-Txnip) to normal mice and performed intraperitoneal glucose tolerance tests (IPGTT), insulin tolerance tests (ITT) and pyruvate tolerance tests (PTT). After Ad-Txnip administration, the expression of genes involved in glucose metabolism, including G6pc and Gck, was analysed using quantitative real-time PCR and western blot. To understand the increased G6pc expression in liver resulting from Txnip overexpression, we performed pull-down assays for TXNIP and small heterodimer partner (SHP). Luciferase reporter assays and chromatin immunoprecipitation using the Txnip promoter were performed to elucidate the interrelationship between carbohydrate response element-binding protein (ChREBP) and transcription factor E3 (TFE3) in the regulation of Txnip expression. RESULTS: Overabundance of TXNIP resulted in impaired glucose, insulin and pyruvate tolerance in normal mice. Ad-Txnip transduction upregulated G6pc expression and caused a decrease in Gck levels in the liver of normal mice and primary hepatocytes. TXNIP increased G6pc expression by forming a complex with SHP, which is known to be a negative modulator of gluconeogenesis. Txnip expression in mouse models of diabetes was decreased by Ad-Tfe3 administration, suggesting that TFE3 may play a negative role through competition with ChREBP at the E-box of the Txnip promoter. CONCLUSIONS/INTERPRETATION: We demonstrated that TXNIP impairs glucose and insulin tolerance in mice by upregulating G6pc through interaction with SHP.
Assuntos
Proteínas de Transporte/metabolismo , Diabetes Mellitus Experimental/metabolismo , Gluconeogênese , Intolerância à Glucose/metabolismo , Glucose-6-Fosfatase/metabolismo , Fígado/metabolismo , Tiorredoxinas/metabolismo , Animais , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/metabolismo , Western Blotting , Proteínas de Transporte/genética , Imunoprecipitação da Cromatina , Teste de Tolerância a Glucose , Glucose-6-Fosfatase/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos NOD , Proteínas Nucleares/metabolismo , Regiões Promotoras Genéticas , Reação em Cadeia da Polimerase em Tempo Real , Tiorredoxinas/genética , Fatores de Transcrição/metabolismo , Ativação Transcricional , Regulação para CimaRESUMO
Although numerous citrus varieties have recently been developed to enhance their quality, information on their quality characteristics is limited. We assessed the quality characteristics of Yellowball, a novel citrus variety, by evaluating its appearance, storability, sensory properties, functionality, and metabolite profiles and then comparing these characteristics with those of its parent varieties, Haruka and Kiyomi. The metabolite profiles between the citrus varieties differed significantly, resulting in distinct physicochemical and functional qualities. The storability of Yellowball was significantly increased compared with that of its parent varieties owing to its strong antifungal activity and unique peel morphology, including the stoma and albedo layers. While we did not investigate the volatile compounds, overall functional activities, and detailed characteristics of each metabolite, our data provide valuable insights into the relationship between citrus metabolites, peel morphology, physicochemical properties, and storability, and demonstrate the potential of Yellowball as a promising variety in the citrus industry.
RESUMO
We determined the expression of the formyl peptide receptor (FPR) family and the functional roles of the FPR family in NK cells. All tested human NK cells express two members of the FPR family (FPR1 and FPR2). The expression of FPR3 was noted to occur in a donor-specific manner. The stimulation of NK cells with FPR family-selective agonists (fMLF (N-formyl-Met-Leu-Phe), MMK-1, F2L, and WKYMVm (Trp-Lys-Tyr-Met-Val-d-Met)) elicited cytolytic activity in resting NK cells, but not in IL-2-activated NK cells; the cytolytic activity was not inhibited by pertussis toxin. The FPR family agonists also stimulated chemotactic migration of IL-2-activated NK cells, but not resting NK cells; the chemotactic migration was completely inhibited by pertussis toxin. WKYMVm stimulates ERK, p38 MAPK, and JNK activities in both resting and IL-2-activated NK cells. WKYMVm-induced chemotactic migration was partially inhibited by PD98059 (2'-amino-3'-methoxyflavone); however, the inhibition of JNK by its selective inhibitor (SP600125, anthra[1,9-cd]pyrazol-6(2H)-one) dramatically inhibited the WKYMVm-induced cytolytic activity. Furthermore, WKYMVm-induced chemotactic migration and cytolytic activity were partly inhibited by FPR family-selective antagonists (cyclosporin H and WRWWWW). Taken together, our findings indicate that human NK cells express functional members of the FPR family, and in turn the activation of the three members of the FPR receptor family elicit cytolytic activity in NK cells, thus suggesting that the receptors are potentially important therapeutic targets for the modulation of NK cell-mediated immune responses.
Assuntos
Células Matadoras Naturais/imunologia , Células Matadoras Naturais/metabolismo , Família Multigênica/imunologia , Receptores de Formil Peptídeo/biossíntese , Quimiotaxia de Leucócito/imunologia , Citotoxicidade Imunológica , Humanos , Ativação Linfocitária/imunologia , Oligopeptídeos/agonistas , Oligopeptídeos/biossíntese , Oligopeptídeos/fisiologia , Receptores de Formil Peptídeo/agonistas , Receptores de Formil Peptídeo/fisiologia , Receptores de Lipoxinas/agonistas , Receptores de Lipoxinas/biossíntese , Receptores de Lipoxinas/fisiologia , Transdução de Sinais/imunologiaRESUMO
F2L, a peptide derived from heme-binding protein, was originally identified as an endogenous ligand for formyl peptide receptor-like (FPRL)2. Previously, we reported that F2L inhibits FPR and FPRL1-mediated signaling in neutrophils. Since endothelial cells express functional FPRL1, we examined the effect of F2L on LL-37 (an FPRL1 agonist)-induced signaling in human umbilical vein endothelial cells (HUVECs). F2L stimulated the chemotactic migration in HUVECs. However, F2L inhibited FPRL1 activity, resulting in the inhibition of cell proliferation and tube formation induced by LL-37 in HUVECs. We suggest that F2L will potentially be useful in the study of FPRL1 signaling and the development of drugs to treat diseases involving the FPRL1 in the vascular system.
Assuntos
Peptídeos Catiônicos Antimicrobianos/antagonistas & inibidores , Proliferação de Células/efeitos dos fármacos , Fatores Quimiotáticos/farmacologia , Endotélio Vascular/efeitos dos fármacos , Peptídeos/farmacologia , Veias Umbilicais/efeitos dos fármacos , Peptídeos Catiônicos Antimicrobianos/farmacologia , Células Cultivadas , Endotélio Vascular/citologia , Humanos , Veias Umbilicais/citologia , CatelicidinasRESUMO
We observed that lysophosphatidylglycerol (LPG) stimulates chemotactic migration in human natural killer (NK) cells. The LPG-induced chemotactic migration of NK cells was completely inhibited by pertussis toxin (PTX). LPG also stimulated the extracellular signal-regulated kinase (ERK) and Akt activities in NK cells. LPG-stimulated ERK activity was inhibited by PTX, indicating the involvement of PTX-sensitive G-proteins. The preincubation of NK cells with an ERK inhibitor (PD98059) or phosphoinositide-3-kinase (PI3K) inhibitors (wortmannin and LY294002) completely inhibited LPG-induced chemotactic migration, suggesting the essential role of ERK and PI3K in the process. Moreover, LPG-induced chemotactic migration in NK cell was inhibited by Ki16425, an LPA(1/3) receptor-selective antagonist, suggesting the involvement of the Ki16425-sensitive G-protein coupled receptor (GPCR) in the process. Taken together, the results indicate that LPG stimulates chemotactic migration in NK cells through GPCR, suggesting a new function of LPG as a modulator of NK cell functioning.
Assuntos
Quimiotaxia , Células Matadoras Naturais/imunologia , Lisofosfolipídeos/imunologia , Receptores de Ácidos Lisofosfatídicos/metabolismo , Androstadienos/farmacologia , Células Cultivadas , Quimiotaxia/efeitos dos fármacos , Cromonas/farmacologia , MAP Quinases Reguladas por Sinal Extracelular/antagonistas & inibidores , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Flavonoides/farmacologia , Humanos , Isoxazóis/farmacologia , Células Matadoras Naturais/efeitos dos fármacos , Lisofosfolipídeos/farmacologia , Morfolinas/farmacologia , Toxina Pertussis/farmacologia , Fosfatidilinositol 3-Quinases/metabolismo , Inibidores de Fosfoinositídeo-3 Quinase , Propionatos/farmacologia , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-akt/metabolismo , Receptores de Ácidos Lisofosfatídicos/agonistas , WortmaninaRESUMO
Lysophosphatidylserine (LPS) was found to stimulate intracellular calcium increase in U87 human glioma cells. LPS also stimulated chemotactic migration of U87 human glioma cells, which was completely inhibited by pertussis toxin (PTX). Moreover, LPS was also found to stimulate ERK, p38 MAPK, JNK, and Akt activities in U87 cells. We observed that LPS-induced U87 chemotaxis was mediated by PI3K, p38 MAPK, and JNK. LPS-induced chemotactic migration in U87 cells was inhibited by Ki16425, an LPA(1/3) receptor-selective antagonist, which suggested that the Ki16425-sensitive G-protein coupled receptor (GPCR) played a role in this process. Moreover, U87 cells were found to uniquely express LPA(1) but not LPA(2-5). In addition, LPS failed to stimulate the NF-kappaB-driven luciferase activity in exogenously LPA(1)-transfected HepG2 cells. Taken together, we propose that LPS stimulates GPCR, which is in contrast to the well-known LPA receptors, thus resulting in the chemotactic migration in U87 human glioma cells.
Assuntos
Neoplasias Encefálicas/metabolismo , Quimiotaxia , Glioma/metabolismo , Lisofosfolipídeos/fisiologia , Receptores Acoplados a Proteínas G/agonistas , Linhagem Celular Tumoral , Quimiotaxia/efeitos dos fármacos , Humanos , Isoxazóis/farmacologia , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Lisofosfolipídeos/farmacologia , Fosfatidilinositol 3-Quinases/metabolismo , Propionatos/farmacologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Receptores Acoplados a Proteínas G/antagonistas & inibidores , Receptores Acoplados a Proteínas G/metabolismo , Receptores de Ácidos Lisofosfatídicos/genética , Receptores de Ácidos Lisofosfatídicos/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismoRESUMO
Serum amyloid A (SAA) and Trp-Lys-Tyr-Met-Val-D-Met (WKYMVm) have been reported as formyl peptide receptor-like 1 (FPRL1) ligands. WKYMVm but not SAA stimulated superoxide generation by human neutrophils. In terms of the downstream signalings triggered by WKYMVm and SAA, both agonists stimulated cytosolic phospholipase A2-mediated arachidonic acid release, a precursor of leukotriene B4 (LTB4) and prostaglandin E2 (PGE2). WKYMVm also strongly stimulated LTB4 production in human neutrophils without affecting PGE2 production, whereas SAA strongly stimulates cyclooxygenase-2 (COX-2) expression and PGE2 production but not LTB4 production. In terms of the receptors responsible for the differential actions of these two agonists, we found that FPRL1 is involved in the production of LTB4 by WKYMVm and PGE2 production by SAA. This study demonstrates that the chemoattractant receptor, FPRL1, can be differentially regulated by distinct ligands to generate different lipid mediators, and thus, different immune responses.
Assuntos
Dinoprostona/biossíntese , Leucotrieno B4/biossíntese , Oligopeptídeos/farmacologia , Receptores de Formil Peptídeo/metabolismo , Proteína Amiloide A Sérica/farmacologia , Animais , Ácido Araquidônico/metabolismo , Linhagem Celular Tumoral , Citosol/efeitos dos fármacos , Citosol/metabolismo , Relação Dose-Resposta a Droga , Eletroforese/métodos , Humanos , Immunoblotting/métodos , Metabolismo dos Lipídeos/efeitos dos fármacos , Neutrófilos/citologia , Neutrófilos/efeitos dos fármacos , Neutrófilos/metabolismo , Fosfolipases A/metabolismo , Fosfolipases A2 , Superóxidos/metabolismo , Fatores de TempoRESUMO
Rat primary chondrocytes express the lysophosphatidic acid (LPA) receptor, LPA1, LPA3, but not LPA2. When chondrocytes were stimulated with LPA, phospholipase C-mediated cytosolic calcium increase was dramatically induced. LPA also stimulated two kinds of mitogen-activated protein kinase, extracellular signal-regulated kinase (ERK) and p38 kinase in chondrocytes. In terms of the LPA-mediated functional modulation of chondrocytes, LPA stimulated cellular proliferation. We examined the signaling pathways involved in LPA-mediated cellular proliferation. LPA-induced chondrocyte proliferation was almost completely blocked by 2'-amino-3'-methoxyflavone (PD98059) but not by 4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)1H-imidazole (SB203580), suggesting that ERK activity is essentially required for the process. Pertussis toxin almost completely inhibited the LPA-induced cellular proliferation and ERK activation, indicating the role of G(i/o) protein(s) in the processes. This study demonstrates the physiological role of LPA on the modulation of rat primary chondrocyte proliferation, and the crucial role played by ERK in the process.
Assuntos
Condrócitos/efeitos dos fármacos , Lisofosfolipídeos/farmacologia , Animais , Cálcio/metabolismo , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Condrócitos/citologia , Ativação Enzimática , MAP Quinases Reguladas por Sinal Extracelular/fisiologia , Proteínas de Ligação ao GTP/fisiologia , Toxina Pertussis/farmacologia , Fosfatidilinositol 3-Quinases/fisiologia , Ratos , Ratos Sprague-Dawley , Receptores de Ácidos Lisofosfatídicos/análise , Fosfolipases Tipo C/fisiologiaRESUMO
Glucokinase (GK), mainly expressed in the liver and pancreatic ß-cells, is critical for maintaining glucose homeostasis. GK expression and kinase activity, respectively, are both modulated at the transcriptional and post-translational levels. Post-translationally, GK is regulated by binding the glucokinase regulatory protein (GKRP), resulting in GK retention in the nucleus and its inability to participate in cytosolic glycolysis. Although hepatic GKRP is known to be regulated by allosteric mechanisms, the precise details of modulation of GKRP activity, by post-translational modification, are not well known. Here, we demonstrate that GKRP is acetylated at Lys5 by the acetyltransferase p300. Acetylated GKRP is resistant to degradation by the ubiquitin-dependent proteasome pathway, suggesting that acetylation increases GKRP stability and binding to GK, further inhibiting GK nuclear export. Deacetylation of GKRP is effected by the NAD(+)-dependent, class III histone deacetylase SIRT2, which is inhibited by nicotinamide. Moreover, the livers of db/db obese, diabetic mice also show elevated GKRP acetylation, suggesting a broader, critical role in regulating blood glucose. Given that acetylated GKRP may affiliate with type-2 diabetes mellitus (T2DM), understanding the mechanism of GKRP acetylation in the liver could reveal novel targets within the GK-GKRP pathway, for treating T2DM and other metabolic pathologies.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas de Transporte/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Glucoquinase/metabolismo , Glucose/metabolismo , Processamento de Proteína Pós-Traducional , Acetilação , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Proteínas de Transporte/genética , Diabetes Mellitus Tipo 2/genética , Glucoquinase/genética , Glucose/genética , Células HeLa , Humanos , Peptídeos e Proteínas de Sinalização Intracelular , Masculino , Camundongos , Camundongos Obesos , Sirtuína 2/genética , Sirtuína 2/metabolismoRESUMO
Post-translational modifications (PTMs) of transcription factors play a crucial role in regulating metabolic homeostasis. These modifications include phosphorylation, methylation, acetylation, ubiquitination, SUMOylation, and O-GlcNAcylation. Recent studies have shed light on the importance of lysine acetylation at nonhistone proteins including transcription factors. Acetylation of transcription factors affects subcellular distribution, DNA affinity, stability, transcriptional activity, and current investigations are aiming to further expand our understanding of the role of lysine acetylation of transcription factors. In this review, we summarize recent studies that provide new insights into the role of protein lysine-acetylation in the transcriptional regulation of metabolic homeostasis.
Assuntos
Fatores de Transcrição/metabolismo , Acetilação , Animais , Diabetes Mellitus Tipo 2/metabolismo , Homeostase/genética , Homeostase/fisiologia , Humanos , Processamento de Proteína Pós-Traducional/genética , Processamento de Proteína Pós-Traducional/fisiologiaRESUMO
Nanoscale assemblies composed of different types of nanoparticles (NPs) can reveal interesting aspects about material properties beyond the functions of individual constituent NPs. This research direction may also represent current challenges in nanoscience toward practical applications. With respect to the assembling method, synthetic or biological nanostructures can be utilized to organize heterogeneous NPs in specific sites via chemical or physical interactions. However, those assembling methods often encounter uncontrollable particle aggregation or phase separation. In this study, we anticipated that the self-segregating properties of block copolymer micelles could be particularly useful for organizing heterogeneous NPs, because the presence of chemically distinct domains such as the core and the corona can facilitate the selective placement of constituent NPs in separate domains. Here, we simultaneously functionalized the core and the corona of micelles by Au NPs and Ag NPs, which exhibited plasmonic and catalytic functions, respectively. Our primary question is whether these plasmonic and catalytic functions can be combined in the assembled structures to engineer the kinetics of a model chemical reaction. To test this hypothesis, the catalytic reduction of 4-nitrophenol was selected to evaluate the collective properties of the micellar assemblies in a chemical reaction.
Assuntos
Nanopartículas Metálicas/química , Micelas , Polímeros/química , Acrilatos/química , Catálise , Ouro/química , Nanopartículas Metálicas/ultraestrutura , Nitrofenóis/química , Poliestirenos/química , Prata/química , Espectrofotometria Ultravioleta , Raios UltravioletaRESUMO
Peroxisome proliferator-activated receptor gamma (PPARγ) belongs to a nuclear receptor superfamily; members of which play key roles in the control of body metabolism principally by acting on adipose tissue. Ligands of PPARγ, such as thiazolidinediones, are widely used in the treatment of metabolic syndromes and type 2 diabetes mellitus (T2DM). Although these drugs have potential benefits in the treatment of T2DM, they also cause unwanted side effects. Thus, understanding the molecular mechanisms governing the transcriptional activity of PPARγ is of prime importance in the development of new selective drugs or drugs with fewer side effects. Recent advancements in molecular biology have made it possible to obtain a deeper understanding of the role of PPARγ in body homeostasis. The transcriptional activity of PPARγ is subject to regulation either by interacting proteins or by modification of the protein itself. New interacting partners of PPARγ with new functions are being unveiled. In addition, post-translational modification by various cellular signals contributes to fine-tuning of the transcriptional activities of PPARγ. In this review, we will summarize recent advancements in our understanding of the post-translational modifications of, and proteins interacting with, PPARγ, both of which affect its transcriptional activities in relation to adipogenesis.
Assuntos
Modelos Genéticos , PPAR gama/fisiologia , Processamento de Proteína Pós-Traducional , Regulação da Expressão Gênica , Homeostase , PPAR gama/genética , PPAR gama/metabolismo , Sumoilação , Fatores de Transcrição/metabolismo , Fatores de Transcrição/fisiologia , UbiquitinaçãoRESUMO
In this study, we observed that lysophosphatidylglycerol (LPG) completely inhibited a formyl peptide receptor like-1 (FPRL1) agonist (MMK-1)-stimulated chemotactic migration in human phagocytes, such as neutrophils and monocytes. LPG also dramatically inhibited IL-1beta production by another FPRL1 agonist serum amyloid A (SAA) in human phagocytes. However, LPG itself induced intracellular calcium increase and superoxide anion production in human phagocytes. Keeping in mind that phagocytes migration and IL-1beta production by FPRL1 are important for the induction of inflammatory response, our data suggest that LPG can be regarded as a useful material for the modulation of inflammatory response induced by FPRL1 activation.
Assuntos
Quimiotaxia de Leucócito/efeitos dos fármacos , Interleucina-1beta/biossíntese , Lisofosfolipídeos/farmacologia , Fagócitos , Receptores de Formil Peptídeo/metabolismo , Receptores de Lipoxinas/metabolismo , Humanos , Monócitos/efeitos dos fármacos , Monócitos/imunologia , Monócitos/metabolismo , Monócitos/fisiologia , Neutrófilos/efeitos dos fármacos , Neutrófilos/imunologia , Neutrófilos/metabolismo , Neutrófilos/fisiologia , Peptídeos/metabolismo , Peptídeos/farmacologia , Fagócitos/efeitos dos fármacos , Fagócitos/imunologia , Fagócitos/metabolismo , Fagócitos/fisiologia , Proteína Amiloide A Sérica/metabolismo , Proteína Amiloide A Sérica/farmacologiaRESUMO
AIM: Serum amyloid A (SAA) is an important mammalian acute reactant. Here, we aim to investigate the effect of SAA on apoptosis and its mechanism of action in human amniotic WISH cells. METHODS: The expression of formyl peptide receptor (FPRL1), which is reported as a SAA receptor, was tested using RT-PCR and ligand binding assay with radio-labeled FPRL1 ligand. The effect of SAA on proliferating cell population was evaluated by thymidine incorporation assay. The protein phosphorylation levels and caspase-3 activity were detected by Western blot assay. RESULTS: SAA inhibits thymidine incorporation in human amniotic WISH cells. A SAA-induced decrease of proliferating cell population was accompanied with nuclear condensation and caspase-3 activation in WISH cells, suggesting that SAA induces WISH cell apoptosis. Since FPRL1 has been reported as a SAA receptor, we investigated the effects of several FRPL1 agonists on a proliferating cell population in WISH cells. Among the tested FPRL1 agonists, only SAA induced a decrease of proliferating cell population in WISH cells. On the downstream signaling of SAA, we found that SAA stimulated extracellular signal-regulated kinase and p38 kinase, which were not inhibited by pertussis toxin (PTX), ruling out the role of PTX-sensitive G-proteins. Furthermore a SAAinduced decrease of proliferating cell population was not affected by PTX, suggesting that SAA inhibits WISH cell apoptosis in a PTX-sensitive G-proteinindependent manner. A SAA-induced decrease of a proliferating cell population was completely blocked by PD98059 and SB203580, suggesting that mitogenactivated protein kinase activities are essentially required for the process. CONCLUSION: SAA is a novel inducer for WISH cell apoptosis, and the PTX-insensitive pathway is involved in the process.
Assuntos
Apoptose/efeitos dos fármacos , Receptores de Formil Peptídeo/genética , Receptores de Lipoxinas/genética , Proteína Amiloide A Sérica/farmacologia , Âmnio/citologia , Âmnio/metabolismo , Western Blotting , Caspase 3/metabolismo , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Flavonoides/farmacologia , Expressão Gênica/efeitos dos fármacos , Humanos , Imidazóis/farmacologia , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Toxina Pertussis/farmacologia , Fosforilação/efeitos dos fármacos , Piridinas/farmacologia , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , Ensaio Radioligante , Receptores de Formil Peptídeo/metabolismo , Receptores de Lipoxinas/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismoRESUMO
Although formyl peptide receptor like 2 (FPRL2) has been regarded as an important classical chemoattractant receptor, its functional role and signaling pathway have not been fully investigated, because of the lack of its specific ligand. Recently F2L, a heme-binding protein fragment peptide, has been reported as an FPRL2-selective endogenous agonist. In the present study, we examined the effect of Trp-Arg-Trp-Trp-Trp-Trp-CONH2 (WRWWWW, WRW4), on F2L-induced cell signaling. WRW4 inhibited the activation of FPRL2 by F2L, resulting in the complete inhibition of intracellular calcium increase and chemotactic migration induced by F2L. WRW4 also completely inhibited F2L-induced NF-kappaB activation in FPRL2-transfected HEK293 cells. WRW4 specifically inhibited F2L-induced intracellular calcium increase and chemotactic migration in mature monocyte-derived dendritic cells, which express FPRL2 but not the other FPR family. Taken together, WRW4 is the first FPRL2 antagonist and is expected to be useful in the study of FPRL2 signaling and in development of drugs against FPRL2-related cellular responses.
Assuntos
Leucócitos Mononucleares/citologia , Oligopeptídeos/farmacologia , Receptores de Formil Peptídeo/antagonistas & inibidores , Transdução de Sinais/efeitos dos fármacos , Cálcio/metabolismo , Proteínas de Transporte/farmacologia , Proteínas Ligantes de Grupo Heme , Hemeproteínas/farmacologia , Humanos , Leucócitos Mononucleares/efeitos dos fármacos , Leucócitos Mononucleares/metabolismo , NF-kappa B/antagonistas & inibidores , NF-kappa B/metabolismo , Neutrófilos/efeitos dos fármacos , Neutrófilos/metabolismo , Receptores de Formil Peptídeo/fisiologiaRESUMO
Lysophosphatidylserine (LPS) may be generated after phosphatidylserine-specific phospholipase A2 activation. However, the effects of LPS on cellular activities and the identities of its target molecules have not been fully elucidated. In this study, we observed that LPS stimulates an intracellular calcium increase in L2071 mouse fibroblast cells, and that this increase was inhibited by 1-[6-((17beta-3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl]-1H-pyrrole-2,5-dione (U-73122) but not by pertussis toxin, suggesting that LPS stimulates calcium signaling via G-protein coupled receptor-mediated phospholipase C activation. Moreover, LPS-induced calcium mobilization was not inhibited by the lysophosphatidic acid receptor antagonist, (S)-phosphoric acid mono-{2-octadec-9-enoylamino-3-[4-(pyridine-2-ylmethoxy)-phenyl]-propyl} ester (VPC 32183), thus indicating that LPS binds to a receptor other than lysophosphatidic acid receptors. It was also found that LPS stimulates two types of mitogen-activated protein kinase [i.e., extracellular signal-regulated protein kinase (ERK) and p38 kinase] in L2071 cells. Furthermore, these LPS-induced ERK and p38 kinase activations were inhibited by pertussis toxin, which suggests the role of pertussis toxin-sensitive G-proteins in the process. In terms of functional issues, LPS stimulated L2071 cell chemotactic migration, which was completely inhibited by pertussis toxin, indicating the involvement of pertussis toxin-sensitive G(i) protein(s). This chemotaxis of L2071 cells induced by LPS was also dramatically inhibited by 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one (LY294002) and by 2'-amino-3'-methoxyflavone (PD98059). This study demonstrates that LPS stimulates at least two different signaling cascades, one of which involves a pertussis toxin-insensitive but phospholipase C-dependent intracellular calcium increase, and the other involves a pertussis toxin-sensitive chemotactic migration mediated by phosphoinositide 3-kinase and ERK.
Assuntos
Cálcio/metabolismo , Quimiotaxia , Fibroblastos/efeitos dos fármacos , Subunidades alfa Gi-Go de Proteínas de Ligação ao GTP/fisiologia , Lisofosfolipídeos/farmacologia , Animais , Proteínas Quinases Dependentes de Cálcio-Calmodulina/antagonistas & inibidores , Ativação Enzimática , Estrenos/farmacologia , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Fibroblastos/metabolismo , Fibroblastos/fisiologia , Flavonoides/farmacologia , Subunidades alfa Gi-Go de Proteínas de Ligação ao GTP/antagonistas & inibidores , Camundongos , Toxina Pertussis/farmacologia , Inibidores de Fosfodiesterase/farmacologia , Fosforilação , Proteínas Proto-Oncogênicas c-akt/metabolismo , Pirrolidinonas/farmacologia , Receptores de Ácidos Lisofosfatídicos/antagonistas & inibidores , Esfingosina/análogos & derivados , Esfingosina/farmacologia , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismoRESUMO
Although the level of serum amyloid A has been reported to be up-regulated during inflammatory response, the role of serum amyloid A on the regulation of inflammation and immune response has not been elucidated. We found that serum amyloid A stimulated the production of tumor necrosis factor (TNF)-alpha and interleukin (IL)-10, which are proinflammatory and anti-inflammatory cytokines, respectively, in human monocytes. Low concentrations of serum amyloid A stimulated TNF-alpha production with maximal activity at 6 h after stimulation, whereas high concentrations of serum amyloid A stimulated IL-10 production with maximal activity at 12 h. The activations of the two cytokines by serum amyloid A occurred at both the transcription and translational levels. Signaling events induced by serum amyloid A included the activation of two mitogen-activated protein kinases (extracellular signal-regulated kinase and p38 kinase), which were found to be required for TNF-alpha and IL-10 production, respectively. The stimulation of formyl peptide receptor-like-1-expressing RBL-2H3 cells, but not of vector-expressing RBL-2H3 cells with serum amyloid A, induced mitogen-activated protein kinases activation and the accumulation of the RNAs of these two cytokines. Together, our findings suggest that serum amyloid A modulates contrary immune responses via formyl peptide receptor-like 1, by inducing TNF-alpha or IL-10, and demonstrate that extracellular signal-regulated kinase and p38 kinase play counteracting roles in this process.