Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 39
Filtrar
1.
Biochimie ; 198: 76-85, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35341928

RESUMO

Macrophages play a pivotal role in atherosclerosis through a variety of events related to cellular oxidative stress. This process is mainly due to an excessive production of reactive oxygen species whose elimination occurs through antioxidant systems including the thioredoxin (Trx) system. In this paper, we investigated whether the Trx system would exhibit circadian rhythmicity in dexamethasone synchronized cultured macrophages and monitored the impact of the rhythmicity of Trx-1 on markers of atherosclerosis. We found that the clock-related genes BMAL-1, PER-2, CRY-1 and REV ERB α exhibited a robust circadian expression. However, the Trx genes family (Trx-1, Trx-2, TrxR1 and TXNIP) did not exhibit a circadian expression at the mRNA level in spite of the presence of E-box elements within the promoter regions of TrxR1 and TXNIP genes. Nevertheless, both Trx-1 and TXNIP exhibited a circadian expression at the protein level and proteasome inhibition abolished the rhythmicity of Trx-1. Moreover, we found a link between low Trx-1 level and elevated atherogenic markers such as 4-HNE, TNF-α and cholesterol accumulation in macrophages. Our results indicate that the Trx gene family does not exhibit the same circadian regulation and that the presence of E-box elements in the TXNIP promoter is not sufficient to ensure a circadian rhythmicity at the transcriptional level. In addition, since a link was found between a low level of Trx-1 protein during circadian rhythm and high levels of atherogenic markers, administration of Trx-1 at certain time points could be an interesting approach to protect against atherosclerosis development.


Assuntos
Aterosclerose , Macrófagos Peritoneais , Animais , Ritmo Circadiano , Macrófagos Peritoneais/metabolismo , Camundongos , Estresse Oxidativo , Tiorredoxinas/genética , Tiorredoxinas/metabolismo
2.
Scand J Med Sci Sports ; 25(2): e197-207, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25048561

RESUMO

The hypothesis that ethnicity and sport practice influence the relationship between maximal power in cycling (P(max)) and countermovement jump (CMJ) has been studied by relating CMJ and P(max) in two groups (volleyball players, VB, and physical education students, PES) including subjects with Caucasian (67 C) or West African (39 WA) origins. Maximal power of the arms (P(max) Arms) was also measured. A two-way analysis of variance (groups × ethnicity) showed significant effects of both factors upon CMJ, which was higher in WA and VB, P = 0.002 and P < 0.001, respectively. Within WA, CMJ was significantly higher in VB (0.732 ± 0.057 m) than in PES (0.661 ± 0.082 m), although there was no difference in P(max) (14.7 ± 1.7 vs 14.7 ± 1.9 W/kg). CMJ was significantly higher in WA (0.69 ± 0.08 vs 0.65 ± 0.09 m in C, P = 0.002) without significant interethnic difference in P(max) (14.7 ± 1.8 in WA, and 14.8 ± 1.9 W/kg in C). The CMJ-P(max) relationships were different in C and WA (P = 0.003). Therefore, CMJ predicted from P(max) would be underestimated in WA. The same difference was observed for the relationship between CMJ and P(max) Arms. These results were confirmed by the comparison with previous P(max) -CMJ relationship in the literature, collected in Caucasian and African subjects with the same protocols.


Assuntos
Braço/fisiologia , População Negra , Perna (Membro)/fisiologia , Esportes/fisiologia , População Branca , Adulto , Desempenho Atlético/fisiologia , Ciclismo/fisiologia , Fenômenos Biomecânicos , Teste de Esforço , Feminino , Humanos , Masculino , Força Muscular/fisiologia , Voleibol
3.
J Sports Med Phys Fitness ; 55(12): 1502-8, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25373468

RESUMO

AIM: To explore the isokinetic concentric strength of the knee muscle groups, and the relationship between the isokinetic knee extensors strength and the vertical jump performance in young elite female basketball players. METHODS: Eighteen elite female basketball players performed a countermovement jump, and an isokinetic knee test using a Biodex dynamometer. The maximal isokinetic peak torque of the knee extensor and flexor muscles was recorded at four angular velocities (90°/s, 180°/s, 240°/s and 300°/s) for the dominant and non-dominant legs. The conventional hamstring/quadriceps ratio (H/Q) was assessed at each angular velocity for both legs. RESULTS: There was no significant difference between dominant and non-dominant leg whatever the angular velocity (all P>0.05). However, the H/Q ratio enhanced as the velocity increased from 180°/s to 300°/s (P<0.05). Furthermore, low to high significant positive correlations were detected between the isokinetic measures of the knee extensors and the vertical jump height. The highest one was found for the knee extensors peak torque at a velocity of 240°/s (r=0.88, P<0.001). CONCLUSION: The results accounted for an optimal velocity at which a strong relationship could be obtained between isokinetic knee extensors strength and vertical jump height. Interestingly, the H/Q ratio of the young elite female basketball players in the present study was unusual as it was close to that generally observed in regular sportsmen.


Assuntos
Atletas , Basquetebol , Traumatismos do Joelho/prevenção & controle , Articulação do Joelho/fisiologia , Joelho/fisiologia , Contração Muscular/fisiologia , Força Muscular/fisiologia , Músculo Esquelético/fisiologia , Adolescente , Análise de Variância , Basquetebol/fisiologia , Fenômenos Biomecânicos , Exercício Físico/fisiologia , Feminino , Humanos , Articulação do Joelho/metabolismo , Perna (Membro)/fisiologia , Músculo Esquelético/metabolismo , Consumo de Oxigênio/fisiologia , Coxa da Perna/fisiologia , Torque
4.
Genet Mol Res ; 9(3): 1326-33, 2010 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-20645257

RESUMO

Peroxisome proliferator-activated receptor delta (PPAR-delta) is a transcription factor implicated in metabolism and inflammation. The +294T/C polymorphism in the PPAR-delta gene is associated with risk of coronary artery disease (CAD) in dyslipidemic women and hypercholesterolemic men. Whether this polymorphism influences the risk of CAD in the absence of dyslipidemia was not known, so we investigated a possible association of this polymorphism with plasma lipid and lipoprotein levels and with risk and outcome of CAD in a normolipidemic Tunisian population. Genotyping was performed by PCR-RFLP in 112 CAD patients and 113 healthy volunteers. The C-allele was significantly more frequent in patients than in controls (0.320 vs 0.189, P = 0.001). This association remained significant after adjustment for age, gender, body mass index, smoking, hypertension, and high-density lipoprotein cholesterol. Subjects carrying either one or two copies of the C-allele had a 2.7-fold higher risk of CAD than subjects homozygous for the T-allele. PPAR-delta genotypes were not associated with lipoprotein concentrations or outcome of CAD. We conclude that PPAR-delta +294T/C polymorphism is an independent risk factor of CAD in normolipidemic Tunisian subjects. The lack of association with lipoprotein concentrations suggests that the effect of the polymorphism on CAD is not mediated through lipoprotein levels in this population and that it may influence the atherosclerotic process through mechanisms involving inflammation.


Assuntos
Doença da Artéria Coronariana/genética , Predisposição Genética para Doença , Lipídeos/sangue , PPAR gama/genética , Polimorfismo de Nucleotídeo Único/genética , Índice de Massa Corporal , Estudos de Casos e Controles , Doença da Artéria Coronariana/sangue , Feminino , Humanos , Lipoproteínas/sangue , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento , Tunísia
5.
Atherosclerosis ; 203(2): 449-53, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18757057

RESUMO

Familial hypercholesterolemia (FH) is an autosomal dominant disease caused by mutations in the low-density lipoprotein receptor (LDLR), apolipoprotein B (APOB), and proprotein convertase subtilisin/kexin type 9 (PCSK9) genes. In previous studies, we have identified novel mutations in Tunisian FH families. In this study, we have extended our investigation to additional families. Five unrelated probands were screened for mutations in the LDLR and APOB genes, using direct sequencing and enzymatic restriction. We identified two novel LDLR mutations: a missense mutation in exon 7: p.Gly343Cys (c.1027G>T), and a nonsense mutation in exon 17: p.Lys816X (c.2446A>T). Using the PolyPhen and SIFT prediction computer programs the p.Gly343Cys is predicted to have a deleterious effect on LDL receptor activity. The missense mutation we found in exon 3, p.Cys89Trp (c.267C>G), has previously been identified in patients from United Kingdom and Spain, and is reported here for the first time in the Tunisian population. Finally, the framshift mutation in exon 10, p.Ser493ArgfsX44, is reported here for the fourth and fifth time in Tunisian families. The latter is the most frequent FH-causing mutation in Tunisia. These LDLR gene mutations enrich the spectrum of mutations causing FH in the Tunisian population. The framshift mutation, p.Ser493ArgfsX44, seems to be a founder mutation in this population.


Assuntos
Análise Mutacional de DNA , Hiperlipoproteinemia Tipo II/diagnóstico , Hiperlipoproteinemia Tipo II/genética , Mutação , Receptores de LDL/genética , Adolescente , Adulto , Idoso , Éxons , Saúde da Família , Feminino , Heterozigoto , Humanos , Hiperlipoproteinemia Tipo II/epidemiologia , Masculino , Linhagem , Polimorfismo Genético , Tunísia
6.
J Fr Ophtalmol ; 31(6 Pt 1): 624, 2008 Jun.
Artigo em Francês | MEDLINE | ID: mdl-18772817

RESUMO

Ochronosis or alkaptonuria is a rare inherited disease. It is characterized by the deposition of dark pigments in collagen-rich tissues, which leads to clinical manifestations such as arthropathy. The ochronotic pigment can be found in the sclera, the conjunctiva, and the limbic cornea. Vision is usually not affected. We report the case of 47-year-old patient who complained of lower back pain. Ophthalmologic examination showed dark pigments in the conjunctiva. The increased levels of homogentisic acid in urine confirmed the diagnosis of ochronosis.


Assuntos
Túnica Conjuntiva/patologia , Ácido Homogentísico/análise , Vértebras Lombares/patologia , Ocronose/patologia , Osteofitose Vertebral/etiologia , Biópsia , Calcinose/diagnóstico por imagem , Calcinose/etiologia , Ácido Homogentísico/urina , Humanos , Disco Intervertebral/diagnóstico por imagem , Disco Intervertebral/patologia , Dor Lombar/diagnóstico por imagem , Dor Lombar/etiologia , Vértebras Lombares/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Ocronose/complicações , Ocronose/diagnóstico , Radiografia , Esclera/patologia , Pigmentação da Pele , Osteofitose Vertebral/diagnóstico por imagem
7.
Clin Chim Acta ; 392(1-2): 25-9, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18355452

RESUMO

BACKGROUND: Familial hypercholesterolemia (FH) is an autosomal dominant inherited disease caused by mutations in either the low-density lipoprotein receptor, the apolipoprotein B or the proprotein convertase subtilisin/kexin type 9 genes. It is characterized by a high concentration of low-density lipoprotein (LDL), which frequently gives rise to premature coronary disease. In this study, we report a novel splice site mutation of the LDL receptor gene in a Tunisian family. METHODS: Seven patients from the family were screened for mutations in the LDLR gene and the apoB gene, using direct sequencing. RT-PCR and study on cultured skin fibroblast were realised to characterize the effect of novel mutation. RESULTS: Direct sequencing of the promoter and 18 exons reveals a G>A substitution in the splice site junction of intron 8 (c.1186+1 G>A). Study on cultured skin fibroblasts showed a residual activity of 10% of the LDL receptor. Reverse transcription, amplification and direct sequencing of RNA from patient's lymphocytes reveal a deletion of the final 51 bp of exon 8 preserving the reading frame. CONCLUSIONS: The study identified a novel splice mutation c.1186+1 G>A in the LDL receptor gene. It causes the utilization of a new cryptic donor splice site 51 bp downstream from the normal site.


Assuntos
Apolipoproteínas B/genética , Fibroblastos/metabolismo , Hipercolesterolemia/genética , Mutação , Sítios de Splice de RNA , Receptores de LDL/genética , Adulto , Idoso , Apolipoproteínas B/metabolismo , Células Cultivadas , Família , Feminino , Humanos , Hipercolesterolemia/sangue , Íntrons , Masculino , Pessoa de Meia-Idade , Receptores de LDL/metabolismo , Tunísia
8.
J Cell Physiol ; 214(1): 183-91, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17579352

RESUMO

The fate and phenotype of lesion macrophages is regulated by cellular oxidative stress. Thioredoxin-1 (Trx-1) plays a major role in the regulation of cellular redox balance, with resultant effects on gene expression and cellular responses including cell growth and death. Trx-1 activity is inhibited by interaction with vitamin D-upregulated protein-1 (VDUP-1). Peroxisome proliferator-activated receptor gamma (PPARgamma) is expressed by human monocyte-derived macrophages (HMDM) and PPARgamma agonism has been reported to decrease expression of inflammatory genes and to promote apoptosis of these cells. To determine whether VDUP-1 may be involved in regulating the effects of PPARgamma agonists in macrophages, we investigated the effect of a synthetic PPARgamma agonist (GW929) on the expression of VDUP-1 in HMDM. GW929 concentration-dependently increased HMDM expression of VDUP-1 (mRNA and protein). Transfection of different fragments of the VDUP-1 promoter as well as gel shift analysis revealed the presence of functional PPARgamma response elements (PPRE) in the promoter. Under conditions in which PPAR agonism altered levels of VDUP-1, caspase-3 activity, and macrophage apoptosis were also elevated. The results suggest that PPARgamma activation stimulates apoptosis in human macrophages by altering the cellular redox balance via regulation of VDUP-1.


Assuntos
Apoptose/efeitos dos fármacos , Proteínas de Transporte/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Macrófagos/efeitos dos fármacos , PPAR gama/agonistas , Aorta/citologia , Proteínas de Transporte/genética , Caspase 3/análise , Caspase 3/metabolismo , Técnicas de Cultura de Células , Diferenciação Celular , Células Cultivadas , Relação Dose-Resposta a Droga , Ensaio de Desvio de Mobilidade Eletroforética , Genes Reporter , Humanos , Marcação In Situ das Extremidades Cortadas , Luciferases/metabolismo , Macrófagos/metabolismo , Monócitos/citologia , Monócitos/metabolismo , Músculo Liso Vascular/citologia , Plasmídeos , Regiões Promotoras Genéticas , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/metabolismo , Elementos de Resposta , Transfecção , Células U937
9.
Parasite ; 12(4): 359-61, 2005 Dec.
Artigo em Francês | MEDLINE | ID: mdl-16402569

RESUMO

Following the arrival of blue-tongue in Tunisia, the authors report the results of the first survey made in Monastir. They show the existence of nine species of Culicoides, three of which are new to the country IC. paolae, C. imicola, C. newsteadi), that now brings to 22 the number of the known species.


Assuntos
Ceratopogonidae/classificação , Ceratopogonidae/parasitologia , Animais , Feminino , Masculino , Filogenia , Tunísia
10.
Arterioscler Thromb Vasc Biol ; 24(10): 1830-5, 2004 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-15308555

RESUMO

OBJECTIVE: Cholesterol accumulation in macrophages is known to alter macrophage biology. In this article we studied the impact of macrophage cholesterol loading on gene expression and identified a novel gene implicated in cell death. METHODS AND RESULTS: The regulated in development and DNA damage response 2 (REDD2) gene was strongly upregulated as THP-1 macrophages are converted to foam cells. These results were confirmed by Northern blot of RNA from human monocyte-derived macrophages (HMDM) treated with oxidized LDL (oxLDL). Human REDD2 shares 86% amino acid sequence identity with murine RTP801-like protein, which is 33% identical to RTP801, a hypoxia-inducible factor 1-responsive gene involved in apoptosis. Treatment of HMDM with desferrioxamine, a molecule that mimics the effect of hypoxia, increased expression of REDD2 in a concentration-dependent fashion. Transfection of U-937 and HMEC cells with a REDD2 expression vector increased the sensitivity of the cells for oxLDL-induced cytotoxicity, by inducing a shift from apoptosis toward necrosis. In contrast, suppression of mRNA expression using siRNA approach resulted in increased resistance to oxLDL treatment. CONCLUSIONS: We showed that stimulation of REDD2 expression in macrophages increases oxLDL-induced cell death, suggesting that REDD2 gene might play an important role in arterial pathology.


Assuntos
Morte Celular/fisiologia , Hipóxia/patologia , Lipoproteínas LDL/farmacologia , Macrófagos/efeitos dos fármacos , Macrófagos/fisiologia , Proteínas/fisiologia , Regulação para Cima/efeitos dos fármacos , Regulação para Cima/fisiologia , Proteínas Adaptadoras de Transdução de Sinal , Arteriosclerose/genética , Linhagem Celular , Linhagem Celular Tumoral , Células Cultivadas , DNA/genética , Desferroxamina/farmacologia , Relação Dose-Resposta a Droga , Endotélio Vascular/química , Endotélio Vascular/metabolismo , Células Espumosas/fisiologia , Humanos , Monócitos/fisiologia , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Transfecção/métodos , Células U937/química , Células U937/metabolismo
11.
Free Radic Biol Med ; 37(1): 71-85, 2004 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-15183196

RESUMO

Uptake of modified low-density lipoproteins (LDLs) by macrophages in the arterial wall is an important event in atherogenesis. Indeed, oxidatively modified LDLs (oxLDLs) are known to affect various cellular processes by modulating oxidation-sensitive signaling pathways. Here we found that the ubiquitous 55 kDa selenoprotein thioredoxin reductase 1 (TrxR1), which is a key enzyme for cellular redox control and antioxidant defense, was upregulated in human atherosclerotic plaques and expressed in foam cells. Using reverse transcription polymerase chain reaction analysis, we also found that oxLDLs, but not native LDLs (nLDLs), dose-dependently increased TrxR1 mRNA in human monocyte-derived macrophages (HMDMs). This stimulating effect was specific for oxLDLs, as pro-inflammatory factors, such as lipopolysaccharides (LPSs), interleukin-1beta (IL-1beta), interleukin-6 (Il-6), and tumor necrosis factor alpha (TNFalpha), under the same conditions, failed to induce TrxR1 mRNA levels to the same extent. Moreover, phorbol ester-differentiated THP-1 cells or HMDMs transiently transfected with TrxR1 promoter fragments linked to a luciferase reporter gene allowed identification of a defined promoter region as specifically responding to the phospholipid component of oxLDLs (p <.05 vs. phospholipid component of nLDLs). Gel mobility shift analyses identified a short 40-nucleotide stretch of the promoter carrying AP-1 and HoxA5 consensus motifs that responded with an altered shift pattern in THP-1 cells treated with oxLDLs, however, without evident involvement of either the Fos, Jun, Nrf2 or HoxA5 transcription factors.


Assuntos
Doenças das Artérias Carótidas/enzimologia , Regulação Enzimológica da Expressão Gênica , Lipoproteínas LDL/farmacologia , Macrófagos/enzimologia , Regiões Promotoras Genéticas/genética , Tiorredoxina Dissulfeto Redutase/genética , Sequência de Bases , Doenças das Artérias Carótidas/cirurgia , Linhagem Celular Tumoral , Endarterectomia das Carótidas , Humanos , Dados de Sequência Molecular , Monócitos/fisiologia , RNA Mensageiro/genética , Tiorredoxina Redutase 1 , Transfecção
12.
FEBS Lett ; 531(2): 122-6, 2002 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-12417298

RESUMO

Metalloproteinases (MMP)-2 and MMP-9 play a role in smooth muscle cell (SMC) migration from the media to the intima following arterial injury. Intravenous administration of adenovirus encoding tissue inhibitor of metalloproteinase-1 (TIMP-1) into balloon-injured rat arteries (3 x 10(11) viral particles/rat; n=7) resulted in a transient expression of TIMP-1 and a significant inhibition of neointima thickening within 16 days ( approximately 40% vs. control; P=0.012). Three days after injury, the number of intimal SMCs was decreased by approximately 98% in TIMP-1-treated rats. However, no alteration was seen in intimal SMC proliferation after 13 days of injury. Therefore, our results show that systemic gene transfer of TIMP-1 is a promising approach in early restenosis treatment.


Assuntos
Angioplastia com Balão/efeitos adversos , Artérias Carótidas/patologia , Estenose das Carótidas/terapia , Terapia Genética , Inibidor Tecidual de Metaloproteinase-1/genética , Adenoviridae/genética , Animais , Estenose das Carótidas/etiologia , Estenose das Carótidas/patologia , Movimento Celular , Vetores Genéticos/administração & dosagem , Humanos , Hiperplasia , Injeções Intravenosas , Cinética , Masculino , Metaloproteinases da Matriz/metabolismo , Músculo Liso Vascular/fisiopatologia , Ratos , Ratos Sprague-Dawley , Inibidor Tecidual de Metaloproteinase-1/sangue
13.
Ann Genet ; 44(1): 25-32, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11334614

RESUMO

We have investigated the lipoprotein lipase (LPL) gene of a 2-year-old patient presenting classical features of the familial LPL deficiency including undetectable LPL activity. DNA sequence analysis of exon 5 identified the patient as a homozygote for the Gly188Glu mutation, frequently involved in this disease. A review of cases of LPL deficiency with molecular study of the LPL gene showed a total number of 221 reported mutations involved in this disease. Gly188Glu was involved in 23.5 % of cases and 74.6 % of mutations were clustered in exons 5 and 6. Based on these observations, we propose a method of screening for mutations in this gene.


Assuntos
Hiperlipoproteinemia Tipo I/genética , Lipase Lipoproteica/deficiência , Lipase Lipoproteica/genética , Mutação de Sentido Incorreto , Substituição de Aminoácidos , Consanguinidade , Éxons , Feminino , Homozigoto , Humanos , Lactente , Lipólise , Lipase Lipoproteica/química , Masculino , Deleção de Sequência
14.
Arterioscler Thromb Vasc Biol ; 20(2): 507-15, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10669650

RESUMO

A new polymorphism located at position -629 (CETP/-629A/C) in the promoter of the cholesteryl ester transfer protein (CETP) gene is described. The -629A allele was associated with lower CETP mass (P<0. 0001) and higher high density lipoprotein cholesterol (P<0.001) than the C allele in a sample of 536 control subjects from the ECTIM study. Transfection studies in HepG2 cells with a luciferase expression vector incorporating a 777-bp fragment of the CETP promoter and containing either A or C at position -629 showed significantly lower luciferase activity with the promoter fragment of the A allele (-25%, P<0.05). By gel-shift assay, DNA-protein interactions were evaluated in nuclear extracts of HepG2 cells with the use of 2 probes (A or C probe) composed of 20 bp of the promoter sequence surrounding the polymorphic site. Two specific complexes of distinct migration rate were identified with the A and the C probe. Competition with an excess of oligonucleotide containing the Sp1 consensus binding site showed that a protein(s) of the Sp transcription factor family was implicated in complex formation with the A probe but not with the C probe. Incubation with specific antibodies indicated that Sp1 and Sp3 bound specifically to the A probe. We introduced mutations in the -629-Sp1 binding site to test its functionality and to define the characteristics of transcription factor binding. We showed, by gel-shift assay, that no nuclear proteins bound to the mutated sequence. Transient transfection of HepG2 cells revealed that the expression of the mutated fragment was significantly increased compared with that of the A promoter fragment (25%, P<0.05). The mutated fragment displayed the same activity as that of the C promoter. These results indicate that Sp1 and/or Sp3 repress CETP promoter activity, whereas nuclear factors binding the C allele are without effect on promoter expression.


Assuntos
Proteínas de Transporte/genética , HDL-Colesterol/sangue , Glicoproteínas , Polimorfismo Genético/fisiologia , Regiões Promotoras Genéticas/genética , Adulto , Sítios de Ligação/fisiologia , Proteínas de Transporte/sangue , Proteínas de Transporte/metabolismo , Proteínas de Transferência de Ésteres de Colesterol , Proteínas de Ligação a DNA/genética , Eletroforese em Gel Bidimensional , Frequência do Gene , Humanos , Pessoa de Meia-Idade , Fragmentos de Peptídeos/metabolismo , Fator de Transcrição Sp1/genética , Fator de Transcrição Sp1/metabolismo , Fator de Transcrição Sp2 , Fatores de Transcrição/genética , Transcrição Gênica
15.
Thromb Res ; 95(5): 255-62, 1999 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-10515290

RESUMO

Tissue factor pathway inhibitor is the major potent physiologic inhibitor of tissue factor-induced coagulation. Several potential binding sites for transcription factors have been described in the 750 bp of the 5' flanking region of the human tissue factor pathway inhibitor gene reported earlier. To identify elements that regulate the expression of tissue factor pathway inhibitor in endothelial, hepatocyte, and monocyte cells, the sequence of an additional 770 bp of tissue factor pathway inhibitor was determined. Comparison of this new sequence as well as that reported earlier with consensus sequences for transcription factor binding sites provided matches for GATA-2, SP1, and c-Myc sequences. Moreover, plasmids containing deletion mutants of the 5' tissue factor pathway inhibitor promoter region and the luciferase reporter gene were transfected into HepG2, ECV304, and THP1 cells. Three negative regulatory elements were localized between -548 to -390, - 390 to -75, and -1158 to -796 relative to the transcriptional start, respectively, in HepG2, ECV304 and THP-1 cells.


Assuntos
Lipoproteínas/genética , Regiões Promotoras Genéticas/genética , Sequência de Bases , Linhagem Celular , Regulação da Expressão Gênica , Humanos , Dados de Sequência Molecular , Análise de Sequência de DNA
16.
Circulation ; 100(5): 533-40, 1999 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-10430768

RESUMO

BACKGROUND: To define the role of metalloproteinases (MMPs) in the development of lipid-rich atherosclerotic lesions in relation to the balance between proteolytic and antiproteolytic activities, we investigated the impact of adenovirus-mediated elevation in the circulating levels of human tissue inhibitor of MMP (TIMP-1) in atherosclerosis-susceptible apolipoprotein E-deficient (apoE(-/-)) mice. METHODS AND RESULTS: Infusion of apoE(-/-) mice fed a lipid-rich diet with rAd.RSV.TIMP-1 (1x10(11) viral particles) resulted in high hepatic expression of TIMP-1. At 2 weeks after injection, plasma TIMP-1 levels ranged from 7 to 24 micrograms/mL (mean 14.8+/-6.8). Marked overexpression of TIMP-1 was transient, with levels of TIMP-1 decreasing to 2.5 to 8 micrograms/mL (mean 4.3+/-2.1) at 4 weeks. Plasma lipid and lipoprotein levels in mice treated with rAd.RSV.TIMP-1 were similar to those treated with rAd.RSV.betaGal. However, rAd.RSV.TIMP-1-infused mice displayed a marked reduction (approximately 32%; P<0.05) in mean lesion area per section (512+/-121 micrometers(2)x10(3); n=12 sections from 4 animals) as compared with rAd.RSV.betaGal-infused mice (750+/-182 micrometers(2)x10(3); n=12 sections from 4 animals). Similarly, marked reduction in macrophage deposition as well as MMP-2, MMP-3, and MMP-13 antigens was observed. CONCLUSIONS: Histological and immunohistologic analyses of atherosclerotic lesions revealed increases in collagen, elastin, and smooth muscle alpha-actin content in mice treated with rAd.RSV.TIMP-1. These qualitative and quantitative features were the consequence of TIMP-1 infiltration from plasma to arterial intima, as immunohistochemical analyses revealed an abundance of TIMP-1 specifically in lesions of rAd.RSV. TIMP-1-treated mice.


Assuntos
Adenoviridae , Apolipoproteínas E/deficiência , Arteriosclerose/patologia , Arteriosclerose/prevenção & controle , Técnicas de Transferência de Genes , Vetores Genéticos , Inibidor Tecidual de Metaloproteinase-1/sangue , Animais , Arteriosclerose/etiologia , Gorduras na Dieta/administração & dosagem , Gorduras na Dieta/efeitos adversos , Feminino , Imuno-Histoquímica , Camundongos , Camundongos Endogâmicos C57BL , Regulação para Cima
17.
Circulation ; 99(3): 420-6, 1999 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-9918530

RESUMO

BACKGROUND: The accumulation of macrophage-derived foam cells in atherosclerotic lesions correlates with increased local release of matrix-degrading metalloproteinases (MMPs) and a thin fibrous cap. The activity of these enzymes is controlled by specific tissue inhibitors of metalloproteinases (TIMPs). METHODS AND RESULTS: Because oxidized low-density lipoprotein (OxLDL) modulates gene expression, we investigated the effect of these particles on the levels of MMP-1, MMP-3, MMP-9, TIMP-1, and TIMP-2 in the culture media of human monocyte-derived macrophages. OxLDL but not native LDL or high-density lipoprotein reduced the level of TIMP-1 in a dose-dependent manner with maximal effect (60% of control) at approximately 100 microg protein/mL. In addition, Northern blotting revealed marked reduction in the abundance of TIMP-1 mRNA in OxLDL-treated cells. Evaluation of the effect of oxysterol components of OxLDL on TIMP-1 production revealed that 25-hydroxycholesterol (1 microg/mL) was the most potent inhibitor ( approximately 30% of control). Such inhibition was partially mediated by interleukin (IL)-8. Indeed, IL-8 (2.5 ng/mL) induced maximal inhibition of TIMP-1 accumulation (30% of control) in 4 of 6 cell preparations. In addition, the inhibitory effect of OxLDL-treated cells in the presence of an anti-IL-8 neutralizing antibody was partially reversed. CONCLUSIONS: Immunohistochemical analyses of human atherosclerotic plaques revealed the expression of TIMP-1 in some but not all macrophage-rich and IL-8-rich areas. Therefore, IL-8 may play a potential atherogenic role by inhibiting local TIMP-1 expression, thereby leading to an imbalance between MMPs and TIMPs at focal sites in the atherosclerotic plaque.


Assuntos
Arteriosclerose/metabolismo , Colagenases/metabolismo , Interleucina-8/metabolismo , Macrófagos/enzimologia , Inibidor Tecidual de Metaloproteinase-1/genética , Anticorpos Monoclonais , Antígenos CD/análise , Antígenos CD/imunologia , Antígenos de Diferenciação Mielomonocítica/análise , Antígenos de Diferenciação Mielomonocítica/imunologia , Arteriosclerose/patologia , Artérias Carótidas/química , Artérias Carótidas/enzimologia , Artérias Carótidas/patologia , Células Cultivadas , LDL-Colesterol/metabolismo , LDL-Colesterol/farmacologia , Colagenases/análise , Colagenases/imunologia , Regulação Enzimológica da Expressão Gênica , Humanos , Interleucina-8/análise , Interleucina-8/imunologia , Macrófagos/química , Macrófagos/efeitos dos fármacos , Metaloproteinase 1 da Matriz , Metaloproteinase 3 da Matriz/análise , Metaloproteinase 3 da Matriz/imunologia , Metaloproteinase 3 da Matriz/metabolismo , Metaloproteinase 9 da Matriz , Monócitos/química , Monócitos/efeitos dos fármacos , Monócitos/enzimologia , Oxirredução , Inibidor Tecidual de Metaloproteinase-1/imunologia , Inibidor Tecidual de Metaloproteinase-2/análise , Inibidor Tecidual de Metaloproteinase-2/genética , Inibidor Tecidual de Metaloproteinase-2/imunologia
18.
Arterioscler Thromb Vasc Biol ; 17(7): 1400-6, 1997 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9261273

RESUMO

We have studied the underlying molecular defect in a patient presenting with recurrent pancreatitis, hypertriglyceridemia, and virtually undetectable postheparin plasma lipoprotein lipase (LPL) mass and activity, who normalized her triglycerides 3 to 6 months after initiation of either medium-chain triglyceride (MCT) oil or omega-3 fatty acid (omega-3-FA) therapy. After treatment, postheparin plasma LPL activity and mass ranged from 24% to 39% of normal and LPL specific activity was normal (1.0 nmol.ng-1.min-1). On discontinuation of MCT oil or omega-3-FA, plasma triglyceride increased to > 2000 mg/dL. Northern blotting revealed both normal size and abundance of LPL mRNA isolated from adipocytes as well as macrophages. Sequence analysis of the LPL gene, which included all 10 exons, intron-exon splice junctions, and 1.7 kb of the 5'-flanking region, and of LPL cDNA failed to identify any mutations. ApoC-II activity and mass assays revealed the presence of normal levels of a fully functional cofactor as well as the absence of circulating plasma inhibitors of lipase function. In summary, we describe a unique patient presenting with classical features of the familial chylomicronemia syndrome who manifests an unusually beneficial therapeutic response to MCT oil and omega-3-FA therapy. Unlike that in most patients with LPL deficiency, the chylomicronemia in this patient is not caused by a mutation in the structural LPL gene but possibly by a posttranscriptional defect. Thus, a subset of LPL-deficient patients with unique genetic defects respond to therapy by normalizing fasting plasma triglycerides; a therapeutic trial with MCT oil should be considered in all patients presenting with the familial chylomicronemia syndrome.


Assuntos
Quilomícrons/sangue , Ácidos Graxos Ômega-3/uso terapêutico , Lipase/sangue , Erros Inatos do Metabolismo Lipídico/dietoterapia , Triglicerídeos/uso terapêutico , Tecido Adiposo/enzimologia , Criança , Feminino , Regulação Enzimológica da Expressão Gênica , Humanos , Lipase Lipoproteica/sangue , Lipase Lipoproteica/genética , Fígado/enzimologia , Macrófagos/enzimologia , Masculino , Linhagem , RNA Mensageiro/metabolismo
19.
Atherosclerosis ; 131(1): 85-95, 1997 May.
Artigo em Inglês | MEDLINE | ID: mdl-9180249

RESUMO

Lecithin:cholesterol acyltransferase (LCAT) is responsible for the formation of the majority of plasma cholesteryl esters. Familial LCAT deficiency is associated with corneal opacity, anemia and proteinurea and typically results in renal failure in the 4-5th decade; this syndrome is equally characterized by the quasi-absence of plasma LCAT activity with variable enzyme mass and very low levels of plasma cholesteryl esters. In this study, we report detailed analyses of plasma lipids and lipoprotein profile in two sisters (CM and ML) presenting classical homozygous LCAT-deficiency; the younger sibling (CM) had proteinurea from an early age whereas the older sister (ML) has never exhibited renal dysfunction. We investigated the molecular defect in the 45 year-old woman (proband CM) exhibiting all clinical and biochemical features of familial LCAT deficiency: a plasma cholesterol level of 105 mg/dl, of which 95% was unesterified, an HDL-cholesterol of 6.5 mg/dl and an apo A-I level of 52 mg/dl. The proband (CM) displayed a plasma cholesterol esterification rate which corresponded to 2% of normal LCAT activity; plasma LCAT protein concentration was 0.56 microg/ml and equivalent to approximately 10% of normal LCAT mass. Analysis by single strand conformation polymorphism (SSCP) of the PCR products corresponding to exons 4 and 5 of the LCAT gene revealed a visible band shift. Sequence analyses of exons 4 + 5 revealed two separate single point mutations: a C --> T transition replacing Arg147 by Trp and a T --> G transition converting Tyr171 to a stop codon. The presence of these two point mutations was confirmed by restriction enzyme analyses: the C --> T transition abolished a MwoI site whereas the T --> G transition created an AvrII site. The Arg147 mutation was associated with a non-secreted protein. The Tyr171 mutation resulted in formation of a truncated protein lacking the catalytic site. In summary, we have identified an LCAT deficient patient corresponding to a compound heterozygote for the Arg147 --> Trp mutation and a new molecular defect involving a Tyr171 --> Stop mutation in the LCAT gene.


Assuntos
Deficiência da Lecitina Colesterol Aciltransferase/genética , Fosfatidilcolina-Esterol O-Aciltransferase/genética , Mutação Puntual , Apolipoproteína A-I/metabolismo , Arginina , Colesterol/sangue , Ésteres do Colesterol/sangue , HDL-Colesterol/sangue , DNA/química , Feminino , Heterozigoto , Humanos , Deficiência da Lecitina Colesterol Aciltransferase/sangue , Pessoa de Meia-Idade , Linhagem , Fosfatidilcolina-Esterol O-Aciltransferase/sangue , Reação em Cadeia da Polimerase , Polimorfismo Conformacional de Fita Simples , Análise de Sequência de DNA , Tirosina
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA