Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 16 de 16
Filtrar
1.
Prep Biochem Biotechnol ; 54(3): 358-373, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-37585713

RESUMO

We extracted Sal B and TIIA from Salvia miltiorrhiza using enzymatic-assisted ethanol extraction. ACONN predicted optimal process conditions. Enzymolysis and alcohol extraction were used, optimizing conditions and evaluating antioxidant activity. ACONN analyzed data and ACO optimized conditions. Lab verification comprehensively evaluated the conditions. The correlation between Sal B, TIIA, and their antioxidant activities was examined. Weights of 0.5739 and 0.4260 evaluated Sal B and TIIA. ACONN had a 97.46% fitting degree. Optimized extraction conditions improved yield and quality, yielding a comprehensive evaluation value of 27.69 with 4.46% average errors. This approach enhances extraction and compound quality. Antioxidant activity strongly correlated with component yield, influenced by extraction conditions. ACONN-optimized extraction improved Sal B and TIIA yield and quality, with potential as natural antioxidants. Integrating machine learning and optimization algorithms in industrial extraction enhances efficiency and environmental preservation.


Assuntos
Salvia miltiorrhiza , Antioxidantes , Algoritmos , Etanol , Aprendizado de Máquina
2.
Medicine (Baltimore) ; 102(46): e35890, 2023 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-37986307

RESUMO

Cerebral ischemia is a cerebrovascular disease with symptoms caused by insufficient blood or oxygen supply to the brain. When blood supplied is restored after cerebral ischemia, secondary brain injury may occur, which is called cerebral ischemia-reperfusion injury (CIRI). In this process, the Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway plays an important role. It mediates neuroinflammation and participates in the regulation of physiological activities, such as cell proliferation, differentiation, and apoptosis. After CIRI, M1 microglia is activated and recruited by the damaged tissue. The inflammatory factors are produced by M1 microglia through the JAK/STAT pathway, eventually leading to cell apoptosis. Meanwhile, the JAK2/STAT3 signaling pathway and the expression of lipocalin-2 and caspase-3 could increase. In the pathway, phosphorylated JAK2 and phosphorylated STAT3 function of 2 ways. They not only promote the proliferation of neurons, but also affect the differentiation direction of neural stem cells by further acting on the Notch signaling pathway. Recently, traditional Chinese medicine (TCM) is a key player in CIRI, through JAK2, STAT3, STAT1 and their phosphorylation. Therefore, the review focuses on the JAK/STAT signaling pathway and its relationship with CIRI as well as the influence of the TCM on this pathway. It is aimed at providing the basis for future clinical research on the molecular mechanism of TCM in the treatment of CIRI.


Assuntos
Isquemia Encefálica , Traumatismo por Reperfusão , Humanos , Janus Quinases/metabolismo , Janus Quinases/farmacologia , Janus Quinases/uso terapêutico , Transdução de Sinais , Medicina Tradicional Chinesa , Fatores de Transcrição STAT/metabolismo , Fatores de Transcrição STAT/farmacologia , Fatores de Transcrição STAT/uso terapêutico , Janus Quinase 2 , Traumatismo por Reperfusão/tratamento farmacológico , Traumatismo por Reperfusão/metabolismo , Isquemia Encefálica/tratamento farmacológico , Fator de Transcrição STAT3/metabolismo , Apoptose
3.
Heliyon ; 9(10): e20200, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37780783

RESUMO

Tetrastigma hemsleyanum (Tetrastigma hemsleyanum Diels et Gilg) is a valuable traditional Chinese medicine with various applications. In this study, we aimed to optimize the extraction process for the total extraction yield of five flavonoid components, namely kaempferol, quercetin, rutin, kaempferol-3-O-rutinoside, and astragalin from the Tetrastigma hemsleyanum root (THR), and explore its potential molecular mechanisms in treating oxidative diseases as well as antioxidant activity. To achieve these objectives, we employed the genetic algorithm-back propagation neural network (GA-BPNN), the Box-Behnken design (BBD) with 4-factors and 3-levels to establish the optimal ethanol extraction process for the total extraction yield of the 5 components. Using public databases, the "component core targets-disease core target genes" networks were built, as well as molecular docking. Furthermore, DPPH was used to examine the antioxidant activity of the extracts obtained from THR under the optimal extraction process. The experimental value of the total extraction yield of the 5 components achieved a maximum of 788.12 mg/kg when the ethanol concentration was 73%, the solid-liquid ratio was 26 g/mL, and the ultrasonic duration was 30 min, and the ultrasonic temperature was 76 °C. When docked with protein molecules such as 6Y8I, quercetin, and other components received moderate to high scores. When the total concentration of the 5 components was 3.033 µg/mL, the DPPH radical scavenging rate was 89.81%. Compared with the BBD method, the GA-BPNN method is more efficient and reliable for optimizing the extraction process of active ingredients in THR because of its good data-fitting ability.

4.
NPJ Regen Med ; 8(1): 20, 2023 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-37024481

RESUMO

When the proliferation of residual hepatocytes is prohibited, biliary epithelial cells (BECs) transdifferentiate into nascent hepatocytes to accomplish liver regeneration. Despite significant interest in transdifferentiation, little is known about the maintenance of nascent hepatocytes in post-injured environments. Here, we perform an N-ethyl-N-nitrosourea (ENU) forward genetic screen and identify a mutant containing a nonsense mutation in the gene nibrin (nbn), which encodes a component of the Mre11-Rad50-Nbn (MRN) complex that activates DNA damage response (DDR). The regenerated hepatocytes cannot be maintained and exhibit apoptosis in the mutant. Mechanistically, the nbn mutation results in the abrogation of ATR-Chk1 signaling and accumulations of DNA damage in nascent hepatocytes, which eventually induces p53-mediated apoptosis. Furthermore, loss of rad50 or mre11a shows similar phenotypes. This study reveals that the activation of DDR by the MRN complex is essential for the survival of BEC-derived hepatocytes, addressing how to maintain nascent hepatocytes in the post-injured environments.

5.
J Alzheimers Dis ; 93(4): 1291-1306, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36463446

RESUMO

BACKGROUND: Considering the strong correlation made between Alzheimer's disease (AD) and the pathology of glucose metabolism disorder, we sought to analyze the effects of fasting blood glucose (FBG) level, fasting plasma insulin (FINS) level, and insulin resistance index (HOMA-IR) on the risk and severity of AD. OBJECTIVE: Reveal the pathological relationship between AD and insulin resistance. METHODS: We searched 5 databases from inception through April 4, 2022. Meta-regression was conducted to identify if there were significant differences between groups. Shapiro-Wilk test and the Q-Q diagram were applied to evaluate the normality of variables. A multiple logistic regression model was employed to explore the association between FBG, FINS, HOMA-IR, and Mini-Mental State Examination scale score (MMSE). RESULTS: 47 qualified articles including 2,981 patients were enrolled in our study. FBG (p < 0.001), FINS (p < 0.001), and HOMA-IR (p < 0.001) were higher in AD patients than in controls. HOMA-IR was negatively correlated with MMSE (p = 0.001) and positively related to the sex ratio (male versus female) (p < 0.05). HOMA-IR obeyed lognormal distribution (p > 0.05), and the 95% bilateral boundary values were 0.73 and 10.67. FBG (p = 0.479) was positively correlated to MMSE, while FINS (p = 0.1657) was negatively correlated with MMSE. CONCLUSION: The increase in the levels of FBG, FINS, and HOMA-IR served as precise indicators of the risk of AD. HOMA-IR was found to be correlated to the increasing severity of AD, especially in male AD patients.


Assuntos
Doença de Alzheimer , Resistência à Insulina , Humanos , Masculino , Feminino , Glicemia/metabolismo , Insulina/metabolismo
6.
Cell Mol Life Sci ; 80(1): 19, 2022 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-36574072

RESUMO

Congenital heart disease (CHD) is the most common birth defect worldwide and a main cause of perinatal and infant mortality. Our previous genome-wide association study identified 53 SNPs that associated with CHD in the Han Chinese population. Here, we performed functional screening of 27 orthologous genes in zebrafish using injection of antisense morpholino oligos. From this screen, 5 genes were identified as essential for heart development, including iqgap2, ptprt, ptpn22, tbck and maml3. Presumptive roles of the novel CHD-related genes include heart chamber formation (iqgap2 and ptprt) and atrioventricular canal formation (ptpn22 and tbck). While deficiency of maml3 led to defective cardiac trabeculation and consequent heart failure in zebrafish embryos. Furthermore, we found that maml3 mutants showed decreased cardiomyocyte proliferation which caused a reduction in cardiac trabeculae due to inhibition of Notch signaling. Together, our study identifies 5 novel CHD-related genes that are essential for heart development in zebrafish and first demonstrates that maml3 is required for Notch signaling in vivo.


Assuntos
Cardiopatias Congênitas , Defeitos dos Septos Cardíacos , Animais , Peixe-Zebra/genética , Estudo de Associação Genômica Ampla , Coração , Cardiopatias Congênitas/genética , Proteínas de Peixe-Zebra/genética
7.
Exp Ther Med ; 18(1): 729-734, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31258708

RESUMO

Diabetic cardiomyopathy (DCM), one of the common diabetic complications, causes a high rate of mortality in patients with diabetes. Tanshinone IIA (TSIIA), one of the components of Salvia miltiorrhiza (Danshen), has anti-oxidative stress activity and is widely used to treat diabetes-associated diseases. However, its efficacy on DCM remains unclear. The present study aimed to investigate the potential therapeutic function of TSIIA on DCM in an experimental diabetic rat model. Streptozotocin (STZ)-induced diabetic rats were intraperitoneally injected with TSIIA for 6 weeks. The present results indicated that blood glucose concentration was slightly reduced in the low-dose TSIIA treatment group. TSIIA injection was also noted to improve cardiac function, and restore loss of mitochondrial cristae, swollen mitochondrial matrix and disorganized myofibrils in myocardial cells, which are thought to be characteristics of apoptosis. Furthermore, TSIIA injection could increase the activity of superoxide dismutase in STZ-induced diabetic rats, and suppress the endoplasmic reticulum (ER) stress signaling pathway via reducing the expression of glucose-regulated protein 78 and C/EBP homologous protein. These results provide evidence that TSIIA may ameliorate DCM in diabetic rats, possibly via suppressing oxidative stress and ER stress activation.

8.
Biochem Biophys Res Commun ; 505(2): 378-384, 2018 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-30262142

RESUMO

Leucyl-tRNA synthetase (LARS) is a kind of aminoacyl-tRNA synthetases (aaRSs), which is important for protein synthesis. Following the discovery of three clinical cases which carry LARS mutations, it has been designated as the infantile liver failure syndrome type 1 (ILFS1) gene. ILFS1 is a kind of infantile hepatopathy, which is difficult to diagnose and manage. As the mechanism underlying this disease is poorly understood and LARS is conserved among vertebrates, we obtained zebrafish larsbcq68 mutant via CRISPR/Cas9 technology to investigate the role of larsb in vivo. In mutant, the proliferation ability of liver was drastically decreased at later stages accompanied with severe DNA damage. Further studies demonstrated that the mTORC1 signaling was hyperactivated in larsbcq68 mutant. Inhibition of mTORC1 signaling pathway by Rapamycin or mTORC1 morpholino can partially rescue the liver failure of the mutants. These data revealed that larsb mutation caused ILFS1-like phenotype in zebrafish, and indicated this mutant may serve as a potential model for ILFS1. Furthermore, we demonstrated that rapamycin treatment can partially rescue the liver defect in mutants, thus providing a practicable therapeutic plan for ILFS1.


Assuntos
Aminoacil-tRNA Sintetases/deficiência , Falência Hepática/enzimologia , Aminoacil-tRNA Sintetases/genética , Animais , Proliferação de Células , Dano ao DNA , Falência Hepática/tratamento farmacológico , Falência Hepática/genética , Falência Hepática/patologia , Proteínas Mutantes , Mutação , Transdução de Sinais , Sirolimo/uso terapêutico , Fatores de Transcrição/fisiologia , Peixe-Zebra , Proteínas de Peixe-Zebra/fisiologia
9.
Perit Dial Int ; 34(1): 33-40, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24293664

RESUMO

BACKGROUND: End-stage renal disease patients have significant cardiovascular morbidity and mortality, but little is known about differences in coagulation profiles between patients on hemodialysis (HD) and on peritoneal dialysis (PD). Given their long-term exposure to glucose-based dialysate, patients on PD can experience metabolic derangements. Theoretically, that exposure should create a more prothrombotic environment than occurs in HD patients. The objective of the present study was to quantify potential differences in baseline coagulation between PD and HD patients. ♢ METHODS: Our single-center cross-sectional study at a large academic health science center enrolled 50 age-, race-, and sex-matched subjects (10 control subjects, 20 HD patients, and 20 PD patients). Measurements included platelet function, platelet receptor distribution, and coagulation dynamics by thromboelastography and Hemodyne hemostasis assay (Hemodyne, Richmond, VA, USA). ♢ RESULTS: Compared with healthy control subjects, patients on both forms of dialysis showed prothrombotic coagulation protein profiles. The tissue-factor pathway was markedly elevated in both groups, but PD was associated with significantly greater concentrations of tissue factor (p = 0.0056) and tissue-factor pathway inhibitor (p = 0.0138). Similarly, compared with patients receiving HD, patients on PD had greater concentrations of fibrinogen (p = 0.0325), which corresponded with platelet hyperfunction as measured by platelet contractile force and clot elastic modulus (p = 0.003 and 0.017 respectively, compared with values in HD patients). Platelet receptor distribution was similar between the groups. ♢ CONCLUSIONS: Compared with patients on HD, patients on PD appear to have a more prothrombotic profile. The clinical relevance of these findings needs to be studied in a prospective manner.


Assuntos
Coagulação Sanguínea , Diálise Renal , Adulto , Coagulação Sanguínea/fisiologia , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Diálise Peritoneal , Projetos Piloto
10.
J Biol Chem ; 285(40): 30496-505, 2010 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-20668334

RESUMO

SOX5 is a transcription factor with homology to the high mobility group box region of the testis-determining factor, SRY. Both the mouse and human SOX5 genes encode a 48-kDa SOX5 protein (S-SOX5) that is only present in tissues containing cells with motile cilia/flagella. The mammalian sperm-associated antigen 6 gene (SPAG6) encodes an axoneme central apparatus protein. Because human and mouse SPAG6 gene promoters contain multiple potential binding sites for SOX5, SPAG6 gene regulation by S-SOX5 was investigated in BEAS-2B cells, a line derived from human bronchial cells. Like FOXJ1, a transcription factor known to be essential for motile ciliogenesis, S-SOX5 stimulated mouse and human SPAG6 promoter function in BEAS-2B cells, but the effect was abrogated when the SOX5 binding sites were mutated or deleted. S-SOX5 and FOXJ1 functioned cooperatively in stimulating SPAG6 promoter activity. The SPAG6 message was up-regulated when S-SOX5 was overexpressed in BEAS-2B cells, and silencing of S-SOX5 by RNA interference down-regulated SPAG6 transcripts. Chromatin immunoprecipitation and EMSA experiments demonstrated that S-SOX5 associates with the SPAG6 promoter directly. The present study demonstrates that SPAG6 is a S-SOX5 target gene, indicating a key role for S-SOX5 in the formation and function of motile cilia.


Assuntos
Cílios/metabolismo , Proteínas dos Microtúbulos/metabolismo , Elementos de Resposta/fisiologia , Fatores de Transcrição SOXD/metabolismo , Transcrição Gênica/fisiologia , Animais , Linhagem Celular , Cílios/genética , Fatores de Transcrição Forkhead/genética , Fatores de Transcrição Forkhead/metabolismo , Humanos , Camundongos , Proteínas dos Microtúbulos/genética , Fatores de Transcrição SOXD/genética
11.
J Biol Chem ; 285(18): 13630-7, 2010 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-20189995

RESUMO

Cellular cholesterol balance induces changes in the inflammatory status of macrophages, and low grade chronic inflammation is increasingly being recognized as one of the key steps in the development of atherosclerosis as well as insulin resistance. Cholesteryl ester hydrolase (CEH) catalyzes the hydrolysis of intracellular stored cholesteryl esters (CEs) and thereby enhances free cholesterol efflux and reduces cellular CE content. We have earlier reported reduced atherosclerosis and lesion necrosis in macrophage-specific CEH transgenic mice on a Ldlr(-/-) background. In the present study, we tested the hypothesis that reduced intracellular accumulation of CE in macrophages from CEH transgenic mice will attenuate expression of proinflammatory mediators, thereby reducing infiltration into adipose tissue, alleviating inflammation, and resulting in improved insulin sensitivity. Western diet fed Ldlr(-/-)CEH transgenic mice showed improved insulin sensitivity as assessed by glucose and insulin tolerance tests. Macrophages from CEH transgenic mice expressed significantly lower levels of proinflammatory cytokines (interleukin-1beta and interleukin-6) and chemokine (MCP-1; monocyte chemoattractant protein). Attenuation of NF-kappaB- and AP-1-driven gene expression was determined to be the underlying mechanism. Infiltration of macrophages into the adipose tissue that increases inflammation and impairs insulin signaling was also significantly reduced in Ldlr(-/-)CEH transgenic mice. In the OP-9 adipocyte peritoneal macrophage co-culture system, macrophages from CEH transgenic mice had a significantly reduced effect on insulin signaling as measured by Akt phosphorylation compared with nontransgenic macrophages. Taken together, these studies demonstrate that macrophage-specific overexpression of CEH decreases expression of proinflammatory mediators and attenuates macrophage infiltration into the adipose tissue, resulting in decreased circulating cytokines and improved insulin sensitivity.


Assuntos
Tecido Adiposo/enzimologia , Colesterol na Dieta/administração & dosagem , Insulina/metabolismo , Macrófagos/enzimologia , Receptores de LDL , Esterol Esterase/metabolismo , Transgenes , Tecido Adiposo/patologia , Animais , Aterosclerose/enzimologia , Aterosclerose/genética , Aterosclerose/patologia , Ésteres do Colesterol/metabolismo , Citocinas/biossíntese , Citocinas/genética , Dieta/efeitos adversos , Regulação da Expressão Gênica/genética , Inflamação/enzimologia , Inflamação/patologia , Insulina/genética , Resistência à Insulina/genética , Macrófagos/patologia , Camundongos , Camundongos Knockout , NF-kappa B/genética , NF-kappa B/metabolismo , Proteína Oncogênica v-akt/genética , Proteína Oncogênica v-akt/metabolismo , Especificidade de Órgãos/genética , Fosforilação/genética , Transdução de Sinais/genética , Esterol Esterase/genética , Fator de Transcrição AP-1/genética , Fator de Transcrição AP-1/metabolismo
12.
Vascul Pharmacol ; 52(1-2): 1-10, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-19878739

RESUMO

Accumulation of cholesteryl esters (CE) stored as cytoplasmic lipid droplets is the main characteristic of macrophage foam cells that are central to the development of atherosclerotic plaques. Since only unesterified or free cholesterol (FC) can be effluxed from the cells to extracellular cholesterol acceptors, hydrolysis of CE is the obligatory first step in CE mobilization from macrophages. This reaction, catalyzed by neutral cholesteryl ester hydrolase (CEH), is increasingly being recognized as the rate-limiting step in FC efflux. CEH, therefore, regulates the process of reverse cholesterol transport and ultimate elimination of cholesterol from the body. In this review, we summarize the earlier controversies surrounding the identity of CEH in macrophages, discuss the characteristics of the various candidates recognized to date and examine their role in mobilizing cellular CE and thus regulating atherogenesis. In addition, physiological requirements to hydrolyze lipid droplet-associated substrate and complexities of interfacial catalysis are also discussed to emphasize the importance of evaluating the biochemical characteristics of candidate enzymes that may be targeted in the future to attenuate atherosclerosis.


Assuntos
Aterosclerose/metabolismo , Ésteres do Colesterol/metabolismo , Mobilização Lipídica/fisiologia , Macrófagos/metabolismo , Animais , Aterosclerose/patologia , Macrófagos/patologia
13.
J Lipid Res ; 49(10): 2212-7, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18599737

RESUMO

Neutral cholesteryl ester hydrolase (CEH)-mediated hydrolysis of cellular cholesteryl esters (CEs) is required not only to generate free cholesterol (FC) for efflux from macrophages but also to release FC from lipoprotein-delivered CE in the liver for bile acid synthesis or direct secretion into the bile. We hypothesized that hepatic expression of CEH would regulate the hydrolysis of lipoprotein-derived CE and enhance reverse cholesterol transport (RCT). Adenoviral-mediated CEH overexpression led to a significant increase in bile acid output. To assess the role of hepatic CEH in promoting flux of cholesterol from macrophages to feces, cholesterol-loaded and [3H]cholesterol-labeled J774 macrophages were injected intraperitoneally into mice and the appearance of [3H]cholesterol in gallbladder bile and feces over 48 h was quantified. Mice overexpressing CEH had significantly higher [3H]cholesterol radiolabel in bile and feces, and it was associated with bile acids. This CEH-mediated increased movement of [3H]cholesterol from macrophages to bile acids and feces was significantly attenuated in SR-BI(-/-) mice. These studies demonstrate that similar to macrophage CEH that rate-limits the first step, hepatic CEH regulates the last step of RCT by promoting the flux of cholesterol entering the liver via SR-BI and increasing hepatic bile acid output.


Assuntos
Colesterol/metabolismo , Fígado/metabolismo , Esterol Esterase/metabolismo , Adenoviridae/genética , Animais , Bile/metabolismo , Ácidos e Sais Biliares/metabolismo , Transporte Biológico , Linhagem Celular , HDL-Colesterol/metabolismo , Fezes , Expressão Gênica , Regulação Enzimológica da Expressão Gênica , Humanos , Lipoproteínas/sangue , Fígado/enzimologia , Macrófagos/metabolismo , Camundongos , Esterol Esterase/genética
14.
J Clin Invest ; 117(10): 2983-92, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17885686

RESUMO

Accumulation of cholesteryl esters (CEs) in macrophage foam cells, central to atherosclerotic plaque formation, occurs as a result of imbalance between the cholesterol influx and efflux pathways. While the uptake, or influx, of modified lipoproteins is largely unregulated, extracellular acceptor-mediated free cholesterol (FC) efflux is rate limited by the intracellular hydrolysis of CE. We previously identified and cloned a neutral CE hydrolase (CEH) from human macrophages and demonstrated its role in cellular CE mobilization. In the present study, we examined the hypothesis that macrophage-specific overexpression of CEH in atherosclerosis-susceptible Ldlr(-/-) mice will result in reduction of diet-induced atherosclerosis. Transgenic mice overexpressing this CEH specifically in the macrophages (driven by scavenger receptor promoter/enhancer) were developed and crossed into the Ldlr(-/-) background (Ldlr(-/-)CEHTg mice). Macrophage-specific overexpression of CEH led to a significant reduction in the lesion area and cholesterol content of high-fat, high-cholesterol diet-induced atherosclerotic lesions. The lesions from Ldlr(-/-)CEHTg mice did not have increased FC, were less necrotic, and contained significantly higher numbers of viable macrophage foam cells. Higher CEH-mediated FC efflux resulted in enhanced flux of FC from macrophages to gall bladder bile and feces in vivo. These studies demonstrate that by enhancing cholesterol efflux and reverse cholesterol transport, macrophage-specific overexpression of CEH is antiatherogenic.


Assuntos
Aterosclerose/patologia , Ésteres do Colesterol/metabolismo , Macrófagos Peritoneais/enzimologia , Esterol Esterase/metabolismo , Animais , Aorta/patologia , Aterosclerose/genética , Colesterol/sangue , Colesterol/metabolismo , Expressão Gênica , Humanos , Camundongos , Camundongos Transgênicos , Necrose/patologia , Receptores de LDL/genética , Esterol Esterase/genética
15.
Am J Physiol Cell Physiol ; 292(1): C405-12, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16971496

RESUMO

Reduction of the lipid burden of atherosclerotic lesion-associated macrophage foam cells is a logical strategy to reduce the plaque volume. Since extracellular cholesterol acceptor-mediated cholesterol efflux is the only recognized mechanism of cholesterol removal from foam cells and this process is rate limited at the level of intracellular cholesterol ester hydrolysis, a reaction catalyzed by neutral cholesteryl ester hydrolase (CEH), we examined the hypothesis that CEH overexpression in the human macrophage monocyte/macrophage cell line THP1 results in increased cholesterol efflux, as well as decreased cellular cholesterol ester accumulation. We generated THP1-CEH cells with stable integration of human macrophage CEH cDNA driven by the cytomegalovirus promoter. Compared with wild-type THP1 cells (THP1-WT), THP1-CEH cells showed increased CEH mRNA expression and increased CEH activity. Efflux of free or unesterified cholesterol by acetylated LDL-loaded THP1-CEH cells to ApoA-I by an ABCA1-dependent pathway or to HDL by an ABCG1-dependent pathway was significantly higher than that in THP1-WT cells. In addition, THP1-CEH cells accumulated significantly lower amount of esterified cholesterol. CEH overexpression, therefore, not only enhances cholesterol efflux but also reduces cellular accumulation of cholesteryl esters. Taken together, these data provide evidence for evaluating CEH expression in human macrophages as a potential target for attenuation of foam cell formation and regression of atherosclerotic plaques.


Assuntos
Colesterol/metabolismo , Macrófagos/metabolismo , Esterol Esterase/metabolismo , Apolipoproteína A-I/farmacologia , Sangue , Linhagem Celular , Ésteres do Colesterol/metabolismo , Expressão Gênica , Humanos , Lipoproteínas HDL/farmacologia , Lipoproteínas LDL/farmacologia , Macrófagos/enzimologia , RNA Mensageiro/metabolismo , Esterol Esterase/genética
16.
Eur J Immunol ; 34(1): 98-107, 2004 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-14971035

RESUMO

Immune complexes (IC) initiate immunoreceptor tyrosine-based inhibition motif (ITIM) signaling and inhibit B cell activation by coligating B cell receptor for antigen (BCR) and FcgammaRII. Nevertheless, IC on follicular dendritic cells (FDC) stimulate rapid germinal center (GC) B cell proliferation suggesting that interactions between IC and FDC render IC capable of B cell activation. To understand this, we studied the kinetics of FDC FcgammaRII and complement receptors 1 and 2 (CR1&2) expressions during the GC reaction and determined whether FDC FcgammaRII could bind Fc in IC and block ITIM signaling. Mice were immunized with sheep red blood cells (SRBC), and CR1&2 and FcgammaRII levels in FDC reticula were monitored. The role of FDC FcgammaRII was studied using anti-BCR-stimulated A20 cells. Levels of FDC FcgammaRII in spleens of SRBC-injected mice increased within 24 h and were dramatically increased (approximately 50-fold) on days 3 and 5. In contrast, CR1&2 levels increased less than twofold. Addition of normal FDC, but not FDC lacking FcgammaRII, reduced and reversed anti-BCR-induced SH2 domain-containing inositol phosphatase (SHIP)-1 phosphorylation in A20 cells. FDC were able to induce normal recall responses even after overnight incubation of the lymphocytes with IC to stimulate ITIM signaling. Engagement of Ig Fc with numerous FcgammaRII on FDC appears to minimize IC-induced ITIM signaling. Thus, rapid up-regulation of FDC FcgammaRII may explain why poorly immunogenic IC are rendered highly immunogenic when presented by FDC in GC.


Assuntos
Linfócitos B/fisiologia , Células Dendríticas Foliculares/imunologia , Receptores de IgG/genética , Transdução de Sinais/imunologia , Animais , Imuno-Histoquímica , Camundongos , Camundongos Endogâmicos BALB C , Monoéster Fosfórico Hidrolases/metabolismo , Receptores de Antígenos de Linfócitos B/metabolismo , Receptores de Complemento/metabolismo , Receptores de IgG/biossíntese , Baço/imunologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...