RESUMO
OBJECTIVE: Liver X receptors (LXRs) modulate cholesterol and fatty acid homeostasis as well as inflammation. This study aims to decipher the role of LXRs in the regulation of polyunsaturated fatty acid (PUFA) synthesis in macrophages in the context of atherosclerosis. APPROACH AND RESULTS: Transcriptomic analysis in human monocytes and macrophages was used to identify putative LXR target genes among enzymes involved in PUFA biosynthesis. In parallel, the consequences of LXR activation or LXR invalidation on PUFA synthesis and distribution were determined. Finally, we investigated the impact of LXR activation on PUFA metabolism in vivo in apolipoprotein E-deficient mice. mRNA levels of acyl-CoA synthase long-chain family member 3, fatty acid desaturases 1 and 2, and fatty acid elongase 5 were significantly increased in human macrophages after LXR agonist treatment, involving both direct and sterol responsive element binding protein-1-dependent mechanisms. Subsequently, pharmacological LXR agonist increased long chain PUFA synthesis and enhanced arachidonic acid content in the phospholipids of human macrophages. Increased fatty acid desaturases 1 and 2 and acyl-CoA synthase long-chain family member 3 mRNA levels as well as increased arachidonic acid to linoleic acid and docosahexaenoic acid to eicosapentaenoic acid ratios were also found in atheroma plaque and peritoneal foam cells from LXR agonist-treated mice. By contrast, murine LXR-deficient macrophages displayed reduced expression of fatty acid elongase 5, acyl-CoA synthase long-chain family member 3 and fatty acid desaturases 1, as well as decreased cellular levels of docosahexaenoic acid and arachidonic acid. CONCLUSIONS: Our results indicate that LXR activation triggers PUFA synthesis in macrophages, which results in significant alterations in the macrophage lipid composition. Moreover, we demonstrate here that LXR agonist treatment modulates PUFA metabolism in atherosclerotic arteries.
Assuntos
Aterosclerose/metabolismo , Ácidos Graxos Insaturados/biossíntese , Macrófagos/metabolismo , Receptores Nucleares Órfãos/metabolismo , Animais , Ácido Araquidônico/metabolismo , Artérias/metabolismo , Células Espumosas/metabolismo , Humanos , Receptores X do Fígado , Camundongos , Receptores Nucleares Órfãos/agonistas , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismoRESUMO
OBJECTIVE: Liver X receptors (LXRs) are oxysterol-activated nuclear receptors that are highly expressed in macrophages and regulate lipid homeostasis and inflammation. Among putative LXR target genes, lysophosphatidylcholine acyltransferase 3 (LPCAT3) involved in the Lands cycle controls the fatty acid composition at the sn-2 position of glycerophospholipids and, therefore, the availability of fatty acids, such as arachidonic acid (AA), used for eicosanoid synthesis. The aim of our study was to determine whether LXRs could regulate the Lands cycle in human macrophages, to assess the consequences in terms of lipid composition and inflammatory response, and to work out the relative contribution of LPCAT3 to the observed changes. APPROACH AND RESULTS: Transcriptomic analysis revealed that LPCAT3 was upregulated by LXR agonists in human macrophages. Accordingly, LXR stimulation significantly increased lysophospholipid acyltransferase activity catalyzed by LPCAT3. Lipidomic analysis demonstrated that LXR activation increased the AA content in the polar lipid fraction, specifically in phosphatidylcholines. The LXR-mediated effects on AA distribution were abolished by LPCAT3 silencing, and a redistribution of AA toward the neutral lipid fraction was observed in this context. Finally, we observed that preconditioning of human macrophages by LXR agonist treatment increased the release of arachidonate-derived eicosanoids, such as prostaglandin E2 and thromboxane after lipopolysaccharide stimulation, with a significant attenuation by LPCAT3 silencing. CONCLUSIONS: Altogether, our data demonstrate that the LXR-mediated induction of LPCAT3 primes human macrophages for subsequent eicosanoid secretion by increasing the pool of AA, which can be mobilized from phospholipids.
Assuntos
1-Acilglicerofosfocolina O-Aciltransferase/genética , Ácido Araquidônico/metabolismo , Eicosanoides/metabolismo , Inflamação/genética , Macrófagos/metabolismo , Receptores Nucleares Órfãos/metabolismo , 1-Acilglicerofosfocolina O-Aciltransferase/metabolismo , Células Cultivadas , Dimetil Sulfóxido/farmacologia , Dinoprostona/metabolismo , Humanos , Inflamação/fisiopatologia , Receptores X do Fígado , Macrófagos/efeitos dos fármacos , Análise em Microsséries , Monócitos/efeitos dos fármacos , Monócitos/metabolismo , Receptores Nucleares Órfãos/efeitos dos fármacos , RNA Mensageiro/análise , Sensibilidade e Especificidade , Regulação para Cima/genéticaRESUMO
Obtaining nesting material presents an optimal foraging problem, collection of materials incurs a cost in terms of risk of predation and energy spent and individuals must balance these costs with the benefits of using that material in the nest. The hazel dormouse, Muscardinus avellanarius is an endangered British mammal in which both sexes build nests. However, whether material used in their construction follows the predictions of optimal foraging theory is unknown. Here, we analyze the use of nesting materials in forty two breeding nests from six locations in Southwest England. Nests were characterized in terms of which plants were used, the relative amount of each plant, and how far away the nearest source was. We found that dormice exhibit a preference for plants closer to the nest, but that the distance they are prepared to travel depends on the plant species. Dormice traveled further to collect honeysuckle Lonicera periclymenum, oak Quercus robur, and beech Fagus sylvatica than any other plants. Distance did not affect the relative amount used, although the proportion of honeysuckle in nests was highest, and more effort was expended collecting honeysuckle, beech, bramble Rubus fruticosus and oak compared to other plants. Our results suggest that not all aspects of optimal foraging theory apply to nest material collection. However, optimal foraging theory is a useful model to examine nest material collection, providing testable predictions. As found previously honeysuckle is important as a nesting material and its presence should be taken account when assessing suitability of sites for dormice.
RESUMO
The molecular events linking lipid accumulation in atherosclerotic plaques to complications such as aneurysm formation and plaque disruption are poorly understood. BALB/c-Apoe(-/-) mice bearing a null mutation in the Npc1 gene display prominent medial erosion and atherothrombosis, whereas their macrophages accumulate free cholesterol in late endosomes and show increased cathepsin K (Ctsk) expression. We now show increased cathepsin K immunostaining and increased cysteinyl proteinase activity using near infrared fluorescence imaging over proximal aortas of Apoe(-/-), Npc1(-/-) mice. In mechanistic studies, cholesterol loading of macrophage plasma membranes (cyclodextrin-cholesterol) or endosomal system (AcLDL+U18666A or Npc1 null mutation) activated Toll-like receptor (TLR) signaling, leading to sustained phosphorylation of p38 mitogen-activated protein kinase and induction of p38 targets, including Ctsk, S100a8, Mmp8, and Mmp14. Studies in macrophages from knockout mice showed major roles for TLR4, following plasma membrane cholesterol loading, and for TLR3, after late endosomal loading. TLR signaling via p38 led to phosphorylation and activation of the transcription factor Microphthalmia transcription factor, acting at E-box elements in the Ctsk promoter. These studies suggest that free cholesterol enrichment of either plasma or endosomal membranes in macrophages leads to activation of signaling via various TLRs, prolonged p38 mitogen-activated protein kinase activation, and induction of Mmps, Ctsk, and S100a8, potentially contributing to plaque complications.
Assuntos
Catepsinas/biossíntese , Membrana Celular/metabolismo , Colesterol/metabolismo , Endossomos/metabolismo , Macrófagos/metabolismo , Transdução de Sinais , Receptor 3 Toll-Like/metabolismo , Receptor 4 Toll-Like/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Proteínas Adaptadoras de Transporte Vesicular/deficiência , Proteínas Adaptadoras de Transporte Vesicular/genética , Animais , Aorta/metabolismo , Apolipoproteínas E/deficiência , Apolipoproteínas E/genética , Calgranulina A , Catepsina K , Membrana Celular/enzimologia , Membrana Celular/imunologia , Células Cultivadas , Elementos E-Box , Endossomos/enzimologia , Endossomos/imunologia , Indução Enzimática , Humanos , Peptídeos e Proteínas de Sinalização Intracelular , Macrófagos/enzimologia , Macrófagos/imunologia , Metaloproteinase 14 da Matriz/metabolismo , Metaloproteinase 8 da Matriz/metabolismo , Camundongos , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fator de Transcrição Associado à Microftalmia/metabolismo , Proteína C1 de Niemann-Pick , Fosforilação , Regiões Promotoras Genéticas , Proteínas/genética , Proteínas/metabolismo , Receptor Ativador de Fator Nuclear kappa-B/metabolismo , Proteínas S100/metabolismo , Fatores de Tempo , Receptor 3 Toll-Like/deficiência , Receptor 3 Toll-Like/genética , Receptor 4 Toll-Like/deficiência , Receptor 4 Toll-Like/genética , Proteínas Quinases p38 Ativadas por Mitógeno/deficiência , Proteínas Quinases p38 Ativadas por Mitógeno/genética , Proteínas rab de Ligação ao GTP/metabolismoRESUMO
Niemann-Pick type C1 (NPC1) promotes the transport of LDL receptor (LDL-R)-derived cholesterol from late endosomes/lysosomes to other cellular compartments. NPC1-deficient cells showed impaired regulation of liver_X receptor (LXR) and sterol regulatory element-binding protein (SREBP) target genes. We observed that Apoe(-/-)Npc1(-/-) mice displayed a marked increase in total plasma cholesterol mainly due to increased VLDL, reflecting decreased clearance. Although nuclear SREBP-2 and Ldlr mRNA levels were increased in Apoe(-/-)Npc1(-/-) liver, LDL-R protein levels were decreased in association with marked induction of proprotein convertase subtilisin/kexin type 9 (Pcsk9) and inducible degrader of the LDL-R (Idol), both known to promote proteolytic degradation of LDL-R. While Pcsk9 is known to be an SREBP-2 target, marked upregulation of IDOL in Apoe(-/-)Npc1(-/-) liver was unexpected. However, several other LXR target genes also increased in Apoe(-/-)Npc1(-/-) liver, suggesting increased synthesis of endogenous LXR ligands secondary to activation of sterol biosynthesis. In conclusion, we demonstrate that NPC1 deficiency has a major impact on VLDL metabolism in Apoe(-/-) mice through modulation of hepatic LDL-R protein levels. In contrast to modest induction of hepatic IDOL with synthetic LXR ligands, a striking upregulation of IDOL in Apoe(-/-)Npc1(-/-) mice could indicate a role of endogenous LXR ligands in regulation of hepatic IDOL.
Assuntos
Apolipoproteínas E , VLDL-Colesterol/metabolismo , Fígado/fisiologia , Proteínas , Receptores de LDL/metabolismo , Serina Endopeptidases/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Animais , Apolipoproteínas E/genética , Apolipoproteínas E/metabolismo , Células Cultivadas , Colesterol/sangue , Peptídeos e Proteínas de Sinalização Intracelular , Lamina Tipo A/metabolismo , Receptores X do Fígado , Macrófagos Peritoneais/citologia , Macrófagos Peritoneais/metabolismo , Camundongos , Camundongos Knockout , Proteína C1 de Niemann-Pick , Receptores Nucleares Órfãos/genética , Receptores Nucleares Órfãos/metabolismo , Pró-Proteína Convertase 9 , Pró-Proteína Convertases , Proteínas/genética , Proteínas/metabolismo , Serina Endopeptidases/genética , Proteína de Ligação a Elemento Regulador de Esterol 1/genética , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo , Proteína de Ligação a Elemento Regulador de Esterol 2/genética , Proteína de Ligação a Elemento Regulador de Esterol 2/metabolismo , Triglicerídeos/sangue , Ubiquitina-Proteína Ligases/genéticaRESUMO
OBJECTIVE: Increasing HDL levels is a potential strategy for the treatment of atherosclerosis. METHODS AND RESULTS: ITX5061, a molecule initially characterized as a p38 MAPK inhibitor, increased HDL-C levels by 20% in a human population of hypertriglyceridemic subjects with low HDL levels. ITX5061 also moderately increased apoA-I but did not affect VLDL/LDL cholesterol or plasma triglyceride concentrations. ITX5061 increased HDL-C in WT and human apoA-I transgenic mice, and kinetic experiments showed that ITX5061 decreased the fractional catabolic rate of HDL-CE and reduced its hepatic uptake. In transfected cells, ITX5061 inhibited SR-BI-dependent uptake of HDL-CE. Moreover, ITX5061 failed to increase HDL-C levels in SR-BI(-/-) mice. To assess effects on atherosclerosis, ITX5061 was given to atherogenic diet-fed Ldlr(+/-) mice with or without CETP expression for 18 weeks. In both the control and CETP-expressing groups, ITX5061-treated mice displayed reductions of early atherosclerotic lesions in the aortic arch -40%, P<0.05), and a nonsignificant trend to reduced lesion area in the proximal aorta. CONCLUSIONS: Our data indicate that ITX5061 increases HDL-C levels by inhibition of SR-BI activity. This suggests that pharmacological inhibition of SR-BI has the potential to raise HDL-C and apoA-I levels without adverse effects on VLDL/LDL cholesterol levels in humans.
Assuntos
Apolipoproteína A-I/sangue , Aterosclerose/prevenção & controle , HDL-Colesterol/sangue , Fenilenodiaminas/farmacologia , Receptores Depuradores Classe B/antagonistas & inibidores , Sulfonamidas/farmacologia , Idoso , Animais , Apolipoproteína A-I/genética , Aterosclerose/sangue , Aterosclerose/etiologia , Proteínas de Transferência de Ésteres de Colesterol/sangue , Proteínas de Transferência de Ésteres de Colesterol/genética , Ésteres do Colesterol/sangue , Dieta Aterogênica , Método Duplo-Cego , Feminino , Humanos , Lipoproteínas HDL/sangue , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Camundongos Knockout , Camundongos Transgênicos , Pessoa de Meia-Idade , Inibidores de Proteínas Quinases/farmacologia , Receptores de LDL/deficiência , Receptores de LDL/genética , Receptores Depuradores Classe B/deficiência , Receptores Depuradores Classe B/genética , Proteínas Quinases p38 Ativadas por Mitógeno/antagonistas & inibidoresRESUMO
BACKGROUND: Two macrophage ABC transporters, ABCA1 and ABCG1, have a major role in promoting cholesterol efflux from macrophages. Peritoneal macrophages deficient in ABCA1, ABCG1, or both show enhanced expression of inflammatory and chemokine genes. This study was undertaken to elucidate the mechanisms and consequences of enhanced inflammatory gene expression in ABC transporter-deficient macrophages. METHODS AND RESULTS: Basal and lipopolysaccharide-stimulated thioglycollate-elicited peritoneal macrophages showed increased inflammatory gene expression in the order Abca1(-/-)Abcg1(-/-)>Abcg1(-/-)>Abca1(-/-)>wild-type. The increased inflammatory gene expression was abolished in macrophages deficient in Toll-like receptor 4 (TLR4) or MyD88/TRIF. TLR4 cell surface concentration was increased in Abca1(-/-)Abcg1(-/-)>Abcg1(-/-)> Abca1(-/-)> wild-type macrophages. Treatment of transporter-deficient cells with cyclodextrin reduced and cholesterol-cyclodextrin loading increased inflammatory gene expression. Abca1(-/-)Abcg1(-) bone marrow-derived macrophages showed enhanced inflammatory gene responses to TLR2, TLR3, and TLR4 ligands. To assess in vivo relevance, we injected intraperitoneally thioglycollate in Abcg1(-/-) bone marrow-transplanted, Western diet-fed, Ldlr-deficient mice. This resulted in a profound inflammatory infiltrate in the adventitia and necrotic core region of atherosclerotic lesions, consisting primarily of neutrophils. CONCLUSIONS: The results suggest that high-density lipoprotein and apolipoprotein A-1 exert anti-inflammatory effects by promoting cholesterol efflux via ABCG1 and ABCA1 with consequent attenuation of signaling via Toll-like receptors. In response to a peripheral inflammatory stimulus, atherosclerotic lesions containing Abcg1(-/-) macrophages experience an inflammatory "echo," suggesting a possible mechanism of plaque destabilization in subjects with low high-density lipoprotein levels.
Assuntos
Transportadores de Cassetes de Ligação de ATP/genética , Aterosclerose/imunologia , Colesterol/metabolismo , Lipoproteínas/genética , Receptor 4 Toll-Like/metabolismo , Transportador 1 de Cassete de Ligação de ATP , Membro 1 da Subfamília G de Transportadores de Cassetes de Ligação de ATP , Transportadores de Cassetes de Ligação de ATP/imunologia , Transportadores de Cassetes de Ligação de ATP/metabolismo , Animais , Aterosclerose/metabolismo , Aterosclerose/fisiopatologia , Regulação da Expressão Gênica/imunologia , Ligantes , Lipopolissacarídeos/farmacologia , Lipoproteínas/imunologia , Lipoproteínas/metabolismo , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Macrófagos/metabolismo , Microdomínios da Membrana/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Camundongos Mutantes , Neutrófilos/imunologia , Receptores de LDL/genética , Receptores de LDL/metabolismo , Transdução de Sinais/imunologia , Receptor 2 Toll-Like/metabolismo , Receptor 3 Toll-Like/metabolismo , Receptor 4 Toll-Like/genética , Receptor 4 Toll-Like/imunologiaRESUMO
BACKGROUND: The formation of an occluding thrombus on a ruptured or eroded atherosclerotic plaque is the hallmark event leading to acute coronary syndromes, myocardial infarction, and sudden death in humans. However, other species are highly resistant to plaque complications, and the specific processes predisposing to plaque destabilization and thrombosis are poorly understood. METHODS AND RESULTS: Mice carrying a null mutation of a gene regulating intracellular cholesterol transport (the Niemann-Pick C1 [Npc1] gene) were crossed with apolipoprotein E (Apoe) knockout mice to examine the effect of Npc1 on atherosclerotic lesion formation. Double-mutant mice showed greater lesion area compared with Apoe-/- littermates. Remarkably, the double mutants also developed large, protruding thrombi associated with the plaques and prominent medial degradation with inflammatory cell infiltration into the adventitia. Genetic studies suggested that the BALB background was permissive for plaque complications compared with C57BL/6J, and a BALB susceptibility locus was mapped by linkage analysis to chromosome 6. Examination of clotting parameters in double-knockout mice revealed that native clotting times were shortened and thrombin-antithrombin complex and soluble CD40 ligand levels were elevated compared with wild-type controls. In addition, cathepsin K was induced in Npc1-/- macrophages, and cathepsin K immunostaining and elastase activity were increased in proximal aortas of double-mutant mice compared with controls. CONCLUSIONS: A defect in intracellular cholesterol trafficking caused by the Npc1 null mutation predisposes to increased lesion formation, atherothrombosis, and medial degradation. Plaque complications may require a procoagulant state and an increased protease activity, leading to plaque destabilization.
Assuntos
Apolipoproteínas E/deficiência , Apolipoproteínas E/genética , Aterosclerose/genética , Aterosclerose/patologia , Proteínas/genética , Trombose/genética , Trombose/patologia , Túnica Média/patologia , Animais , Apolipoproteínas E/fisiologia , Aterosclerose/metabolismo , Colesterol/genética , Colesterol/metabolismo , Predisposição Genética para Doença , Peptídeos e Proteínas de Sinalização Intracelular , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Mutantes , Mutação , Proteína C1 de Niemann-Pick , Proteínas/fisiologia , Trombose/enzimologia , Túnica Média/metabolismoRESUMO
BACKGROUND AND AIMS: LPCAT3 plays a major role in phospholipid metabolism in the liver and intestine. However, the impact of LPCAT3 on hematopoietic cell and macrophage functions has yet to be described. Our aim was to understand the functions of LPCAT3 in macrophages and to investigate whether LPCAT3 deficiency in hematopoietic cells may affect atherosclerosis development. METHODS: Mice with constitutive Lpcat3 deficiency (Lpcat3-/-) were generated. We used fetal hematopoietic liver cells to generate WT and Lpcat3-/- macrophages in vitro and to perform hematopoietic cell transplantation in recipient Ldlr-/- mice. RESULTS: Lpcat3-deficient macrophages displayed major reductions in the arachidonate content of phosphatidylcholines, phosphatidylethanolamines and, unexpectedly, plasmalogens. These changes were associated with altered cholesterol homeostasis, including an increase in the ratio of free to esterified cholesterol and a reduction in cholesterol efflux in Lpcat3-/- macrophages. This correlated with the inhibition of some LXR-regulated pathways, related to altered cellular availability of the arachidonic acid. Indeed, LPCAT3 deficiency was associated with decreased Abca1, Abcg1 and ApoE mRNA levels in fetal liver cells derived macrophages. In vivo, these changes translated into a significant increase in atherosclerotic lesions in Ldlr-/- mice with hematopoietic LPCAT3 deficiency. CONCLUSIONS: This study identifies LPCAT3 as a key factor in the control of phospholipid homeostasis and arachidonate availability in myeloid cells and underlines a new role for LPCAT3 in plasmalogen metabolism. Moreover, our work strengthens the link between phospholipid and sterol metabolism in hematopoietic cells, with significant consequences on nuclear receptor-regulated pathways and atherosclerosis development.
Assuntos
1-Acilglicerofosfocolina O-Aciltransferase/deficiência , Aterosclerose/enzimologia , Colesterol/metabolismo , Células-Tronco Hematopoéticas/enzimologia , Macrófagos/enzimologia , Fosfolipídeos/metabolismo , Placa Aterosclerótica , 1-Acilglicerofosfocolina O-Aciltransferase/genética , Transportador 1 de Cassete de Ligação de ATP/genética , Transportador 1 de Cassete de Ligação de ATP/metabolismo , Membro 1 da Subfamília G de Transportadores de Cassetes de Ligação de ATP/genética , Membro 1 da Subfamília G de Transportadores de Cassetes de Ligação de ATP/metabolismo , Animais , Apolipoproteínas E/genética , Apolipoproteínas E/metabolismo , Ácido Araquidônico/metabolismo , Aterosclerose/genética , Aterosclerose/patologia , Células Cultivadas , Modelos Animais de Doenças , Predisposição Genética para Doença , Transplante de Células-Tronco Hematopoéticas , Receptores X do Fígado/metabolismo , Macrófagos/transplante , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fenótipo , Receptores de LDL/deficiência , Receptores de LDL/genéticaRESUMO
Activated monocytes are present in the arterial walls of hypertensive patients and animals. Monocyte chemoattractant protein-1 (MCP-1), which controls monocyte function through its receptor (CCR2), is implicated in hypertensive inflammatory changes in the arterial wall. The role of CCR2 expression on monocytes in hypertension-induced vascular remodeling, however, has not been addressed. We hypothesized that CCR2 on monocytes is critical in hypertension-induced vascular inflammation and remodeling. Hypertension was induced by infusion of angiotensin II (Ang II) into wild-type mice, CCR2-deficient (CCR2-/-) mice, and bone marrow-transferred mice with a leukocyte-selective CCR2 deficiency (BMT-CCR2-/-). In wild-type mice, Ang II increased CCR2 intensity in circulating monocytes, which was prevented by an Ang II type-1 (AT1) receptor blocker or blunted in AT1 receptor-deficient mice. Enhanced CCR2 intensity on monocytes was observed in hypertensive patients and rats, and was reduced by treatment with the Ang II receptor blocker, supporting the clinical relevance of the observation in mice. In CCR2-/- and BMT-CCR2-/- mice, Ang II-induced vascular inflammation and vascular remodeling (aortic wall thickening and fibrosis) were blunted as compared with control mice. In contrast, Ang II-induced left ventricular hypertrophy developed in CCR2-/- and BMT-CCR2-/- mice. The present study suggests that CCR2 expression in monocytes has a critical role in vascular inflammation and remodeling in Ang II-induced hypertension, and possibly in other forms of hypertension.
Assuntos
Hipertensão/metabolismo , Monócitos/fisiologia , Receptores de Quimiocinas/fisiologia , Angiotensina II/toxicidade , Bloqueadores do Receptor Tipo 1 de Angiotensina II , Animais , Aorta/efeitos dos fármacos , Aorta/metabolismo , Transplante de Medula Óssea , Quimiocina CCL2/biossíntese , Quimiocina CCL2/genética , Quimiotaxia de Leucócito/fisiologia , Inibidores Enzimáticos/farmacologia , Humanos , Hipertensão/induzido quimicamente , Hipertrofia Ventricular Esquerda/etiologia , Hipertrofia Ventricular Esquerda/metabolismo , Imidazóis/farmacologia , Inflamação/metabolismo , Bombas de Infusão Implantáveis , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Monócitos/efeitos dos fármacos , NG-Nitroarginina Metil Éster/farmacologia , Óxido Nítrico Sintase/antagonistas & inibidores , Óxido Nítrico Sintase Tipo II , Óxido Nítrico Sintase Tipo III , Olmesartana Medoxomila , Projetos Piloto , Quimera por Radiação , Ratos , Ratos Endogâmicos SHR , Ratos Endogâmicos WKY , Receptor Tipo 1 de Angiotensina/deficiência , Receptor Tipo 1 de Angiotensina/genética , Receptores CCR2 , Receptores de Quimiocinas/deficiência , Receptores de Quimiocinas/genética , Proteínas Recombinantes de Fusão/fisiologia , Superóxido Dismutase/genética , Tetrazóis/farmacologia , Regulação para Cima/efeitos dos fármacosRESUMO
We report a case of intracranial germ cell tumor that showed pathological changes from neurohypophyseal germinoma to mixed germ cell tumors consisting exclusively of undifferentiated sarcomatous component after radiochemotherapy. Three surgical specimens and autopsied brain from the patient were histologically examined. An initial specimen from the neurohypophyseal tumor was diagnosed as germinoma with a two-cell pattern. Five years later, after repeated radiochemotherapy, the second specimen resected from the right temporal lobe showed mixed germ cell tumors consisting of the three components of germinoma, choriocarcinoma, and immature teratoma. Six months later after intensive radiotherapy, the right temporal tumor recurred and was surgically removed. The histological diagnosis was mixed germ cell tumors with abundant immature teratoma component. The patient died of uncontrollable tumor growth with repeated intratumoral hemorrhages. The autopsied brain showed sarcoma with angionecrosis. This pathological alteration indicated an increase in the sarcomatous component after undergoing various treatments. We discuss the histological changes of intracranial germ cell tumor modified by treatment.
Assuntos
Neoplasias Encefálicas/patologia , Neoplasias Embrionárias de Células Germinativas/patologia , Neoplasias Hipofisárias/tratamento farmacológico , Neoplasias Hipofisárias/radioterapia , Sarcoma/patologia , Lobo Temporal/patologia , Adolescente , Coriocarcinoma/patologia , Terapia Combinada , Evolução Fatal , Germinoma/patologia , Humanos , Hemorragias Intracranianas/etiologia , Hemorragias Intracranianas/patologia , Imageamento por Ressonância Magnética , Masculino , Inclusão em Parafina , Neuro-Hipófise/patologia , Teratoma/patologia , Fixação de TecidosRESUMO
We previously showed that nonsteroidal anti-inflammatory drugs (NSAID) such as sulindac sulfide, which has chemopreventive activity, modulate the expression of several genes detected by microarray analysis. Activating transcription factor 3 (ATF3) was selected for further study because it is a transcription factor involved in cell proliferation, apoptosis, and invasion, and its expression is repressed in human colorectal tumors as compared with normal adjacent tissue. In this report, we show that ATF3 mRNA and protein expression are up-regulated in HCT-116 human colorectal cancer cells following treatment with NSAIDs, troglitazone, diallyl disulfide, and resveratrol. To ascertain the biological significance of ATF3, we overexpressed full-length ATF3 protein in the sense and antisense orientations. Overexpression of ATF3 in the sense orientation decreased focus formation in vitro and reduced the size of mouse tumor xenografts by 54% in vivo. Conversely, overexpression of antisense ATF3 was protumorigenic in vitro, however, not in vivo. ATF3 in the sense orientation did not modulate apoptosis, indicating another mechanism is involved. With microarray analysis, several genes relating to invasion and metastasis were identified by ATF3 overexpression and were confirmed by real-time reverse transcription-PCR, and several of these genes were modulated by sulindac sulfide, which inhibited invasion in these cells. Furthermore, overexpression of ATF3 inhibited invasion to a similar degree as sulindac sulfide treatment, whereas antisense ATF3 increased invasion. In conclusion, ATF3 represents a novel mechanism in which NSAIDs exert their anti-invasive activity, thereby linking ATF3 and its gene regulatory activity to the biological activity of these compounds.
Assuntos
Anti-Inflamatórios não Esteroides/farmacologia , Neoplasias Colorretais/metabolismo , Inibidores de Ciclo-Oxigenase/farmacologia , Invasividade Neoplásica/patologia , Sulindaco/análogos & derivados , Fatores de Transcrição/metabolismo , Fator 3 Ativador da Transcrição , Compostos Alílicos/farmacologia , Animais , Apoptose/efeitos dos fármacos , Cromanos/farmacologia , Neoplasias Colorretais/patologia , Dissulfetos/farmacologia , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Células HCT116 , Humanos , Masculino , Camundongos , Camundongos Nus , Análise em Microsséries , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Resveratrol , Estilbenos/farmacologia , Sulindaco/farmacologia , Tiazolidinedionas/farmacologia , Fatores de Transcrição/genética , Transplante Heterólogo , Troglitazona , Regulação para CimaRESUMO
BACKGROUND: Therapeutic angiogenesis by delivery of vascular endothelial growth factor (VEGF) has attracted attention. However, the role and function of VEGF in experimental restenosis (neointimal formation) after vascular intraluminal injury have not been addressed. METHODS AND RESULTS: We report herein that blockade of VEGF by soluble VEGF receptor 1 (sFlt-1) gene transfer attenuated neointimal formation after intraluminal injury in rabbits, rats, and mice. sFlt-1 gene transfer markedly attenuated the early vascular inflammation and proliferation and later neointimal formation. sFlt-1 gene transfer also inhibited increased expression of inflammatory factors such as monocyte chemoattractant protein-1 and VEGF. Intravascular VEGF gene transfer enhanced angiogenesis in the adventitia but did not reduce neointimal formation. CONCLUSIONS: Increased expression and activity of VEGF are essential in the development of experimental restenosis after intraluminal injury by recruiting monocyte-lineage cells.
Assuntos
Lesões das Artérias Carótidas/terapia , Artéria Femoral/lesões , Terapia Genética , Monócitos/patologia , Proteínas/fisiologia , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Cicatrização/fisiologia , Adenoviridae/genética , Animais , Transplante de Medula Óssea , Lesões das Artérias Carótidas/patologia , Cateterismo/efeitos adversos , Divisão Celular , Linhagem da Célula , Constrição Patológica , Endotélio Vascular/fisiologia , Proteínas da Matriz Extracelular , Artéria Femoral/patologia , Regulação da Expressão Gênica/efeitos dos fármacos , Vetores Genéticos/farmacologia , Vetores Genéticos/uso terapêutico , Hiperplasia , Inflamação/prevenção & controle , Masculino , Camundongos , Camundongos Transgênicos , Cadeias Pesadas de Miosina , Neovascularização Fisiológica , Miosina não Muscular Tipo IIB , Proteínas/genética , Coelhos , Ratos , Ratos Endogâmicos WKY , Receptores de Fatores de Crescimento do Endotélio Vascular/biossíntese , Receptores de Fatores de Crescimento do Endotélio Vascular/genética , Proteínas Recombinantes de Fusão/fisiologia , Recidiva , Regeneração , Solubilidade , Transdução Genética , Transfecção , Túnica Íntima/patologia , Fator A de Crescimento do Endotélio Vascular/biossíntese , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/fisiologiaRESUMO
BACKGROUND: Stromal cell-derived factor-1alpha (SDF-1alpha) is implicated as a chemokine for endothelial progenitor cells (EPCs). We therefore hypothesized that SDF-1alpha gene transfer would induce therapeutic neovascularization in vivo by functioning as a chemokine of EPC. METHODS AND RESULTS: To examine SDF-1alpha-induced mobilization of EPC, we used bone marrow-transplanted mice whose blood cells ubiquitously express beta-galactosidase (LacZ). We produced unilateral hindlimb ischemia in the mice and transfected them with plasmid DNA encoding SDF-1alpha or empty plasmids into the ischemic muscles. SDF-1alpha gene transfer mobilized EPCs into the peripheral blood, augmented recovery of blood perfusion to the ischemic limb, and increased capillary density associated with partial incorporation of LacZ-positive cells into the capillaries of the ischemic limb, suggesting that SDF-1alpha induced vasculogenesis and angiogenesis. SDF-1alpha gene transfer did not affect ischemia-induced expression of vascular endothelial growth factor (VEGF) but did enhance Akt and endothelial nitric oxide synthase (eNOS) activity. Blockade of VEGF or NOS prevented all such SDF-1alpha-induced effects. CONCLUSIONS: SDF-1alpha gene transfer enhanced ischemia-induced vasculogenesis and angiogenesis in vivo through a VEGF/eNOS-related pathway. This strategy might become a novel chemokine therapy for next generation therapeutic neovascularization.
Assuntos
Quimiocinas CXC/genética , Terapia Genética , Isquemia/terapia , Neovascularização Fisiológica , Óxido Nítrico Sintase/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Animais , Células da Medula Óssea/citologia , Transplante de Medula Óssea , Capilares/crescimento & desenvolvimento , Quimiocina CXCL12 , Quimiotaxia , Endotélio Vascular/citologia , Membro Posterior/irrigação sanguínea , Isquemia/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Óxido Nítrico Sintase/genética , Óxido Nítrico Sintase Tipo II , Óxido Nítrico Sintase Tipo III , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-akt , Transdução de Sinais , Células-Tronco/fisiologia , TransfecçãoRESUMO
BACKGROUND: Monocyte infiltration into the arterial wall and its activation is the central event in atherogenesis. Thus, monocyte chemoattractant protein-1 (MCP-1) might be a novel therapeutic target against atherogenesis. We and others recently reported that blockade or abrogation of the MCP-1 pathway attenuates the initiation of atheroma formation in hypercholesterolemic mice. It remains unclear, however, whether blockade of MCP-1 can limit progression or destabilization of established lesions. METHODS AND RESULTS: We report here that blockade of MCP-1 by transfecting an N-terminal deletion mutant of the MCP-1 gene limited progression of preexisting atherosclerotic lesions in the aortic root in hypercholesterolemic mice. In addition, blockade of MCP-1 changed the lesion composition into a more stable phenotype, ie, containing fewer macrophages and lymphocytes, less lipid, and more smooth muscle cells and collagen. This strategy decreased expression of CD40 and the CD40 ligand in the atherosclerotic plaque and normalized the increased chemokine (RANTES and MCP-1) and cytokine (tumor necrosis factor alpha, interleukin-6, interleukin-1beta, and transforming growth factor beta(1)) gene expression. These data suggest that MCP-1 is a central mediator in the progression and destabilization of established atheroma. CONCLUSIONS: The results of the present study suggest that the inflammatory responses mediated by MCP-1 are important in atherosclerosis and its complications.
Assuntos
Apolipoproteínas E/deficiência , Arteriosclerose/terapia , Quimiocina CCL2/antagonistas & inibidores , Terapia Genética/métodos , Animais , Apolipoproteínas E/genética , Arteriosclerose/genética , Arteriosclerose/patologia , Antígenos CD40/metabolismo , Ligante de CD40/metabolismo , Quimiocina CCL2/genética , Quimiocina CCL2/metabolismo , Quimiocinas/genética , Quimiocinas/metabolismo , Colagenases/metabolismo , Citocinas/genética , Citocinas/metabolismo , Modelos Animais de Doenças , Progressão da Doença , Técnicas de Transferência de Genes , Hipercolesterolemia/genética , Metaloproteinase 13 da Matriz , Metaloproteinase 9 da Matriz/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/metabolismo , Fragmentos de Peptídeos/administração & dosagem , Fragmentos de Peptídeos/genética , Receptores CCR2 , Receptores de Quimiocinas/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Linfócitos T/patologia , Resultado do Tratamento , Regulação para Cima/efeitos dos fármacosRESUMO
BACKGROUND: Peroxisome proliferator-activated receptor-gamma activators have recently been implicated as regulators of cellular proliferation and inflammatory response such as cytokine expression. Because proinflammatory cytokines play a critical role in left ventricular (LV) remodeling after myocardial infarction (MI), we examined the effects of pioglitazone treatment in an experimental model of chronic heart failure. METHODS AND RESULTS: Mice with extensive anterior MI were treated with placebo or pioglitazone (3 mg x kg(-1) x d(-1)) as a dietary supplement for 4 weeks starting 6 hours after surgery. Infarct size and glucose levels were similar among all groups. LV cavity dilatation and dysfunction by echocardiography were significantly attenuated in MI mice given pioglitazone. LV end-diastolic pressure was increased in MI mice and was significantly reduced by pioglitazone treatment. Pioglitazone partially normalized LV dP/dt(max) and dP/dt(min), indices of LV contractile function, which were significantly reduced in MI mice. Improvement of LV function by pioglitazone was accompanied by a decrease in myocyte hypertrophy and interstitial fibrosis and a reduced expression of tumor necrosis factor-alpha, transforming growth factor-beta, and monocyte chemoattractant protein-1 genes in the noninfarcted LV from MI mice. LV inducible nitric oxide synthase and gelatinase B protein levels were increased in MI and were not altered by pioglitazone treatment. CONCLUSIONS: Pioglitazone improved LV remodeling and function in mice with post-MI heart failure. This effect was associated with an attenuated LV expression of inflammatory cytokines and chemokines. Peroxisome proliferator-activated receptor-gamma ligands have promise as preventive and therapeutic agents against heart failure.
Assuntos
Insuficiência Cardíaca/prevenção & controle , Infarto do Miocárdio/tratamento farmacológico , Receptores Citoplasmáticos e Nucleares/agonistas , Tiazóis/farmacologia , Tiazolidinedionas , Fatores de Transcrição/agonistas , Remodelação Ventricular/efeitos dos fármacos , Administração Oral , Animais , Aspartato Aminotransferases/sangue , Glicemia/efeitos dos fármacos , Citocinas/genética , Citocinas/metabolismo , Modelos Animais de Doenças , Progressão da Doença , Esquema de Medicação , Ecocardiografia , Expressão Gênica/efeitos dos fármacos , Insuficiência Cardíaca/etiologia , Ventrículos do Coração/efeitos dos fármacos , Ventrículos do Coração/metabolismo , Ventrículos do Coração/patologia , Hemodinâmica/efeitos dos fármacos , Masculino , Metaloproteinase 9 da Matriz/genética , Metaloproteinase 9 da Matriz/metabolismo , Camundongos , Infarto do Miocárdio/complicações , Infarto do Miocárdio/patologia , Miocárdio/metabolismo , Óxido Nítrico Sintase/genética , Óxido Nítrico Sintase/metabolismo , Óxido Nítrico Sintase Tipo II , Variações Dependentes do Observador , Tamanho do Órgão/efeitos dos fármacos , Pioglitazona , RNA Mensageiro/metabolismo , Reprodutibilidade dos Testes , Taxa de Sobrevida , Disfunção Ventricular Esquerda/etiologia , Disfunção Ventricular Esquerda/prevenção & controleRESUMO
BACKGROUND: It remains unclear whether vascular endothelial growth factor (VEGF) is a proarteriosclerotic or an antiarteriosclerotic factor. We recently reported that long-term inhibition of nitric oxide by administering Nomega-nitro-L-arginine methyl ester (L-NAME) induces coronary vascular inflammation and arteriosclerosis. METHODS AND RESULTS: We used this animal model to investigate the role of VEGF in arteriosclerosis. We blocked VEGF activity in vivo by transfecting with plasmid DNA encoding the murine soluble FLT-1 (sFLT-1) gene into thigh muscle. Soluble FLT-1 can suppress VEGF activity both by sequestering VEGF and by functioning as a dominant-negative inhibitor of VEGF receptors. We observed vascular inflammation associated with increased VEGF expression within 3 days of L-NAME administration, which was prevented by pretreatment with ACE inhibitor, angiotensin II receptor antagonist, or neutralizing monocyte chemoattractant protein-1 antibody. The sFLT-1 gene transfer attenuated the early vascular inflammation and prevented late arteriosclerosis. The sFLT-1 gene transfer also inhibited increased expression of monocyte chemoattractant protein-1 and transforming growth factor-beta, indicating creation of a positive feedback loop to cause arteriosclerosis. CONCLUSIONS: VEGF is necessary in the development of arteriosclerosis by mediating monocyte recruitment and activation in this model.
Assuntos
Arteriosclerose/metabolismo , Fatores de Crescimento Endotelial/metabolismo , Linfocinas/metabolismo , Monócitos/metabolismo , Óxido Nítrico/antagonistas & inibidores , Proteínas Proto-Oncogênicas/administração & dosagem , Receptores Proteína Tirosina Quinases/administração & dosagem , Animais , Arteriosclerose/etiologia , Arteriosclerose/imunologia , Arteriosclerose/patologia , Bioensaio , Pressão Sanguínea/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Quimiocina CCL2/genética , Quimiocina CCL2/metabolismo , Quimiotaxia de Leucócito/efeitos dos fármacos , Vasos Coronários/efeitos dos fármacos , Vasos Coronários/imunologia , Vasos Coronários/patologia , Modelos Animais de Doenças , Fatores de Crescimento Endotelial/antagonistas & inibidores , Inibidores Enzimáticos/administração & dosagem , Expressão Gênica/efeitos dos fármacos , Transferência Genética Horizontal , Vetores Genéticos/administração & dosagem , Vetores Genéticos/biossíntese , Vetores Genéticos/genética , Inflamação/imunologia , Inflamação/patologia , Injeções Intramusculares , Linfocinas/antagonistas & inibidores , Masculino , Camundongos , Monócitos/imunologia , Monócitos/patologia , NG-Nitroarginina Metil Éster/administração & dosagem , Neovascularização Fisiológica/efeitos dos fármacos , Óxido Nítrico/sangue , Peptidil Dipeptidase A/metabolismo , Proteínas Proto-Oncogênicas/biossíntese , Proteínas Proto-Oncogênicas/genética , RNA Mensageiro/biossíntese , Ratos , Ratos Endogâmicos WKY , Receptores Proteína Tirosina Quinases/biossíntese , Receptores Proteína Tirosina Quinases/genética , Tempo , Fator de Crescimento Transformador beta/genética , Fator de Crescimento Transformador beta/metabolismo , Fator A de Crescimento do Endotélio Vascular , Receptor 1 de Fatores de Crescimento do Endotélio Vascular , Fatores de Crescimento do Endotélio VascularRESUMO
Prevention of restenosis after coronary intervention is a major clinical challenge, which highlights the need of new therapeutic options. Vascular injury may involve inflammatory responses that accelerate the recruitment and activation of monocytes through the activation of chemotactic factors, including monocyte chemoattractant protein-1 (MCP-1). However, there is no definitive evidence supporting the role of MCP-1 in restenosis. We recently devised a new strategy for anti-MCP-1 gene therapy by transfecting an N-terminal deletion mutant of the MCP-1 gene into skeletal muscles. We demonstrate here that this strategy suppressed monocyte infiltration/activation in the injured site and markedly inhibited restenotic changes (neointimal hyperplasia) after balloon injury of the carotid artery in rats and monkeys. This strategy also suppressed the local production of MCP-1 and inflammatory cytokines. Therefore, monocyte infiltration and activation mediated by MCP-1 are essential in the development of restenotic changes after balloon injury. This strategy may be a useful form of gene therapy against human restenosis.
Assuntos
Lesões das Artérias Carótidas/prevenção & controle , Quimiocina CCL2/genética , Túnica Íntima/patologia , Actinas/análise , Animais , Artérias Carótidas/metabolismo , Artérias Carótidas/patologia , Lesões das Artérias Carótidas/etiologia , Cateterismo/efeitos adversos , Quimiocina CCL2/sangue , Quimiocina CCL2/metabolismo , Quimiocinas/metabolismo , Citocinas/metabolismo , Hiperplasia , Imuno-Histoquímica , Macaca fascicularis , Masculino , Músculo Liso/química , Mutação , Plasmídeos/genética , Antígeno Nuclear de Célula em Proliferação/análise , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos , Ratos Endogâmicos WKY , Receptores CCR2 , Receptores de Quimiocinas/genética , Receptores de Quimiocinas/metabolismo , Fatores de Tempo , Transfecção , Túnica Íntima/metabolismo , Fator de von Willebrand/análiseRESUMO
OBJECTIVE: Vascular endothelial growth factor (VEGF) is upregulated after arterial injury. Its role in the pathogenesis of neointimal formation after periadventitial injury, however, has not been addressed. METHODS AND RESULTS: Expression of VEGF and its receptors but not that of placental growth factor markedly increased with the development of neointimal formation in hypercholesterolemic mice after cuff-induced periarterial injury. Transfection with the murine soluble Flt-1 (sFlt-1) gene to block VEGF in vivo in mice inhibited early inflammation and later neointimal formation. The sFlt-1 gene transfer did not affect plasma lipid levels but attenuated increased expression of VEGF, Flt-1, Flk-1, monocyte chemoattractant protein-1, and other inflammation-promoting factors. Mice with Flt-1 kinase deficiency also displayed reduced neointimal formation. CONCLUSIONS: Inflammatory changes mediated by VEGF and Flt-1 signals play an important role in the pathogenesis of neointimal formation after cuff-induced periadventitial injury. VEGF might promote neointimal formation by acting as a proinflammatory cytokine.
Assuntos
Neovascularização Fisiológica/fisiologia , Transdução de Sinais/fisiologia , Túnica Íntima/fisiologia , Receptor 1 de Fatores de Crescimento do Endotélio Vascular/metabolismo , Animais , Apolipoproteínas E/deficiência , Apolipoproteínas E/fisiologia , Artéria Femoral/química , Artéria Femoral/lesões , Artéria Femoral/metabolismo , Regulação da Expressão Gênica/genética , Técnicas de Transferência de Genes , Hiperplasia/sangue , Hiperplasia/enzimologia , Imuno-Histoquímica/métodos , Lipídeos/sangue , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Isoformas de Proteínas/genética , Solubilidade , Fatores de Tempo , Túnica Íntima/patologia , Receptor 1 de Fatores de Crescimento do Endotélio Vascular/deficiência , Receptor 1 de Fatores de Crescimento do Endotélio Vascular/genética , Receptor 1 de Fatores de Crescimento do Endotélio Vascular/imunologia , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/biossíntese , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/imunologia , Fatores de Crescimento do Endotélio Vascular/genéticaRESUMO
OBJECTIVE: Chronic inflammatory processes might be involved in the progression and destabilization of atherosclerotic plaques. Therefore, identification of the mechanism underlying arterial inflammatory function might lead to the development of novel therapeutic strategies. Angiotensin II (AngII) is implicated in atherogenesis by activating the vascular inflammation system, mainly through monocyte chemotaxis. Therefore, we hypothesized that AngII increases plaque size and promotes destabilization of established atheromas by activating the monocyte chemoattractant protein-1 (MCP-1) pathway. METHODS AND RESULTS: We report here that 4-week infusion of AngII not only increased plaque size but also induced a destabilization phenotype (ie, increased macrophages and lipids and decreased collagen and smooth muscle cells) of pre-existing atherosclerotic lesions of hypercholesterolemic mice. AngII also enhanced the gene expression of inflammatory cytokines (TNFalpha, IL-6, etc.) and chemokines (MCP-1, CCR2, etc). Blockade of MCP-1, by transfecting the deletion mutant of the human MCP-1 gene into the skeletal muscles, limited AngII-induced progression and destabilization of established atherosclerotic lesions and suppressed the induction of proinflammatory genes. CONCLUSIONS: These data suggest that MCP-1 functions as a central inflammatory mediator in the AngII-induced progression and changes in plaque composition of established atheroma.