RESUMO
BACKGROUND AND AIMS: High density lipoprotein (HDL) exerts an anti-atherosclerotic effect via reverse cholesterol transport (RCT). Several phases of RCT are transcriptionally controlled by Liver X receptors (Lxrs). Although macrophage Lxrs reportedly promote RCT, it is still uncertain whether hepatic Lxrs affect RCT in vivo. METHODS: To inhibit Lxr-dependent pathways in mouse livers, we performed hepatic overexpression of sulfotransferase family cytosolic 2B member 1 (Sult2b1) using adenoviral vector (Ad-Sult2b1). Ad-Sult2b1 or the control virus was intravenously injected into wild type mice and Lxrα/ß double knockout mice, under a normal or high-cholesterol diet. A macrophage RCT assay and an HDL kinetic study were performed. RESULTS: Hepatic Sult2b1 overexpression resulted in reduced expression of Lxr-target genes - ATP-binding cassette transporter G5/G8, cholesterol 7α hydroxylase and Lxrα itself - respectively reducing or increasing cholesterol levels in HDL and apolipoprotein B-containing lipoproteins (apoB-L). A macrophage RCT assay revealed that Sult2b1 overexpression inhibited fecal excretion of macrophage-derived 3H-cholesterol only under a high-cholesterol diet. In an HDL kinetic study, Ad-Sult2b1 promoted catabolism/hepatic uptake of HDL-derived cholesterol, thereby reducing fecal excretion. Finally, in Lxrα/ß double knockout mice, hepatic Sult2b1 overexpression increased apoB-L levels, but there were no differences in HDL levels or RCT compared to the control, indicating that Sult2b1-mediated effects on HDL/RCT and apoB-L were distinct: the former was Lxr-dependent, but not the latter. CONCLUSIONS: Hepatic Lxr inhibition negatively regulates circulating HDL levels and RCT by reducing Lxr-target gene expression.
RESUMO
OBJECTIVE: Reverse cholesterol transport (RCT) is a major mechanism by which HDL (high-density lipoprotein) protects against atherosclerosis. Endothelial lipase (EL) reportedly reduces HDL levels, which, in theory, would increase atherosclerosis. However, it remains unclear whether EL affects RCT in vivo. APPROACH AND RESULTS: Adenoviral vectors expressing EL or luciferase were intravenously injected into mice, and a macrophage RCT assay was performed. As expected, hepatic EL overexpression markedly reduced HDL levels. In parallel, plasma 3H-cholesterol counts from the EL-expressing mice decreased by 85% compared with control. Surprisingly, there was no difference in fecal 3H-cholesterol excretion between the groups. Kinetic studies revealed increased catabolism/hepatic uptake of 3HDL-cholesteryl ether, resulting in no change in fecal HDL-cholesteryl ester excretion in the mice. To explore underlying mechanisms for the preservation of RCT despite low HDL levels in the EL-expressing mice, we investigated the effects of hepatic SR-BI (scavenger receptor class B type I) knockdown. RCT assay revealed that knockdown of SR-BI alone reduced fecal excretion of macrophage-derived 3H-cholesterol. Interestingly, hepatic EL overexpression under SR-BI inhibition further attenuated fecal tracer counts as compared with control. Finally, we observed that EL overexpression enhanced in vivo RCT under pharmacological inhibition of hepatic ABCA1 (ATP-binding cassette transporter A1) by probucol. CONCLUSIONS: Hepatic EL expression compensates for reduced macrophage-derived cholesterol efflux to plasma because of low HDL levels by promoting cholesterol excretion to bile/feces via an SR-BI pathway, maintaining overall RCT in vivo. In contrast, EL-modified HDL might negatively regulate RCT via hepatic ABCA1. Despite extreme hypoalphalipoproteinemia, RCT is maintained in EL-expressing mice via SR-BI/ABCA1-dependent pathways.
Assuntos
Transportador 1 de Cassete de Ligação de ATP/metabolismo , HDL-Colesterol/sangue , Lipase/biossíntese , Fígado/enzimologia , Macrófagos Peritoneais/metabolismo , Receptores Depuradores Classe B/metabolismo , Adenoviridae/genética , Animais , Indução Enzimática , Técnicas de Transferência de Genes , Vetores Genéticos , Células Hep G2 , Humanos , Lipase/genética , Camundongos , Camundongos Endogâmicos C57BL , MicroRNAs/genética , MicroRNAs/metabolismo , Células RAW 264.7 , Interferência de RNA , Receptores Depuradores Classe B/genéticaRESUMO
Primary mural endocarditis is an extremely rare infection in which nonvalvular endocardial involvement is seen without any cardiac structural abnormalities such as ventricular septal defects. The rapid and precise diagnosis of this disease remains challenging. We present 2 cases (67- and 47-year-old male patients) of pathologically confirmed primary mural endocarditis that could have been detected by initial transthoracic echocardiography in the emergency department. Transthoracic echocardiography and transesophageal echocardiography play critical roles in the early recognition and confirmation of primary mural endocarditis.
Assuntos
Ecocardiografia Transesofagiana , Endocardite/diagnóstico , Endocardite/terapia , Infecções Estafilocócicas/diagnóstico , Infecções Estafilocócicas/terapia , Idoso , Diagnóstico Diferencial , Endocardite/diagnóstico por imagem , Evolução Fatal , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
OBJECTIVE: Oxidized products of probucol, spiroquinone and diphenoquinone, were shown to increase cell cholesterol release and plasma high-density lipoprotein (HDL) by inhibiting degradation of ATP-binding cassette transporter A1. We investigated whether these compounds enhance reverse cholesterol transport in mice. APPROACH AND RESULTS: Spiroquinone and diphenoquinone increased ATP-binding cassette transporter A1 protein (2.8- and 2.6-fold, respectively, P<0.01) and apolipoprotein A-I-mediated cholesterol release (1.4- and 1.4-fold, P<0.01 and P<0.05, respectively) in RAW264.7 cells. However, diphenoquinone, but not spiroquinone, enhanced cholesterol efflux to HDL (+12%, P<0.05), whereas both increased ATP-binding cassette transporter G1 protein, by 1.8- and 1.6-fold, respectively. When given orally to mice, both compounds significantly increased plasma HDL-cholesterol, by 19% and 20%, respectively (P<0.05), accompanied by an increase in hepatic and macrophage ATP-binding cassette transporter A1 but not ATP-binding cassette transporter G1. We next evaluated in vivo reverse cholesterol transport by injecting RAW264.7 cells labeled with (3)H-cholesterol intraperitoneally into mice. Both spiroquinone and diphenoquinone increased fecal excretion of the macrophage-derived (3)H-tracer, by 25% and 28% (P<0.01 and P<0.05), respectively. spiroquinone/diphenoquinone did not affect fecal excretion of HDL-derived (3)H-cholesterol, implying that macrophage-to-plasma was the most important step in spiroquinone/diphenoquinone-mediated promotion of in vivo reverse cholesterol transport. Finally, spiroquinone significantly reduced aortic atherosclerosis in apolipoprotein E null mice when compared with the vehicle. CONCLUSIONS: Spiroquinone and diphenoquinone increase functional ATP-binding cassette transporter A1 in both the macrophages and the liver, elevate plasma HDL-cholesterol, and promote overall reverse cholesterol transport in vivo. These compounds are promising as therapeutic reagents against atherosclerosis.
Assuntos
Transportador 1 de Cassete de Ligação de ATP/efeitos dos fármacos , Androstadienos/farmacologia , Anticolesterolemiantes/farmacologia , Aorta/efeitos dos fármacos , Doenças da Aorta/prevenção & controle , Aterosclerose/prevenção & controle , Colesterol/sangue , Hipercolesterolemia/tratamento farmacológico , Macrófagos/efeitos dos fármacos , Probucol/farmacologia , Quinonas/farmacologia , Transportador 1 de Cassete de Ligação de ATP/metabolismo , Animais , Aorta/metabolismo , Aorta/patologia , Doenças da Aorta/sangue , Doenças da Aorta/genética , Doenças da Aorta/patologia , Apolipoproteína A-I/sangue , Apolipoproteínas E/deficiência , Apolipoproteínas E/genética , Aterosclerose/sangue , Aterosclerose/genética , Aterosclerose/patologia , Transporte Biológico , HDL-Colesterol/sangue , Modelos Animais de Doenças , Fezes/química , Hipercolesterolemia/sangue , Hipercolesterolemia/genética , Fígado/efeitos dos fármacos , Fígado/metabolismo , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Oxirredução , Placa Aterosclerótica , Células RAW 264.7 , Fatores de TempoRESUMO
Reverse cholesterol transport (RCT) is pivotal in the return of excess cholesterol from peripheral tissues to the liver for excretion in bile and eventually feces. RCT from macrophages is a critical anti-atherogenicity mechanism of HDL. As the cholesterol absorption inhibitor ezetimibe promoted RCT in mice, which lack cholesterol ester transfer protein (CETP), we investigated its effects in hamsters, which have CETP. A high-cholesterol diet (HC) increased cholesterol levels throughout lipoprotein fractions and ezetimibe markedly reduced VLDL/LDL cholesterol levels under both normal chow (NC) and HC. However, ezetimibe did not affect and reduced HDL-cholesterol levels under NC and HC, respectively. Intraperitoneal injection of (3)H-cholesterol pre-labeled macrophages in an in vivo RCT assay increased tracer accumulation in the liver but reduced it in bile under HC, and these changes were completely cancelled by ezetimibe. Under both NC and HC, ezetimibe reduced tracer levels in the liver but increased them in feces, indicating promotion of RCT in vivo. We performed a RCT assay using hamsters subjected to bile duct ligation (BDL) to clarify whether a transintestinal cholesterol efflux (TICE) pathway contributes to ezetimibe's enhancement of RCT. BDL markedly inhibited macrophage-derived (3)H-cholesterol excretion to feces and cancelled ezetimibe's stimulatory effect on RCT, suggesting that biliary cholesterol excretion is a major contributor in RCT promotion by ezetimibe but the contribution of the TICE pathway is minimal. In conclusions, ezetimibe exerts an additive anti-atherogenic property by enhancing RCT in hamsters. Our findings suggest that this property is independent of the TICE pathway.
Assuntos
Anticolesterolemiantes/farmacologia , Azetidinas/farmacologia , Bile/efeitos dos fármacos , HDL-Colesterol/metabolismo , Fígado/efeitos dos fármacos , Macrófagos/efeitos dos fármacos , Animais , Bile/metabolismo , Ductos Biliares/cirurgia , Transporte Biológico/efeitos dos fármacos , Proteínas de Transferência de Ésteres de Colesterol/metabolismo , LDL-Colesterol/metabolismo , VLDL-Colesterol/metabolismo , Cricetinae , Dieta , Ezetimiba , Fezes/química , Fígado/metabolismo , Macrófagos/citologia , Macrófagos/metabolismo , Masculino , TrítioRESUMO
BACKGROUND: Cystic echinococcosis (CE) is a globally distributed cestode zoonosis that causes hepatic cysts. Although Echinococcus granulosus sensu stricto (s.s.) is the major causative agent of CE worldwide, recent molecular epidemiological studies have revealed that E. canadensis is common in countries where camels are present. One such country is Mongolia. METHODOLOGY/PRINCIPAL FINDINGS: Forty-three human hepatic CE cases that were confirmed histopathologically at the National Center of Pathology (NCP) in Ulaanbaatar (UB) were identified by analysis of mitochondrial cox 1 gene as being caused by either E. canadensis (n=31, 72.1%) or E. granulosus s.s. (n=12, 27.9%). The majority of the E. canadensis cases were strain G6/7 (29/31, 93.5%). Twenty three haplotypes were identified. Sixteen of 39 CE cases with data on age, sex and province of residence were citizens of UB (41.0%), with 13 of the 16 cases from UB caused by E. canadensis (G6/7) (81.3%). Among these 13 cases, nine were children (69.2%). All pediatric cases (n â=â 18) were due to E. canadensis with 17 of the 18 cases (94.4%) due to strain G6/7. Serum samples were available for 31 of the 43 CE cases, with 22 (71.0%) samples positive by ELISA to recombinant Antigen B8/1 (rAgB). Nine of 10 CE cases caused by E. granulosus s.s. (90.0%) and 13 of 20 CE cases by E. canadensis (G6/7) (65.0%) were seropositive. The one CE case caused by E. canadensis (G10) was seronegative. CE cases caused by E. granulosus s.s. showed higher absorbance values (median value 1.131) than those caused by E. canadensis (G6/7) (median value 0.106) (p â=â 0.0137). CONCLUSION/SIGNIFICANCE: The main species/strains in the study population were E. canadenis and E. granulossus s.s. with E. canadensis the predominant species identified in children. The reason why E. canadensis appears to be so common in children is unknown.
Assuntos
Equinococose Hepática/diagnóstico , Equinococose Hepática/epidemiologia , Echinococcus/isolamento & purificação , Adolescente , Adulto , Idoso , Animais , Anticorpos Anti-Helmínticos/sangue , Criança , Pré-Escolar , Echinococcus/classificação , Echinococcus/genética , Echinococcus/imunologia , Complexo IV da Cadeia de Transporte de Elétrons/genética , Feminino , Haplótipos , Humanos , Masculino , Pessoa de Meia-Idade , Epidemiologia Molecular , Dados de Sequência Molecular , Mongólia/epidemiologia , Fatores de Risco , Análise de Sequência de DNA , Adulto JovemRESUMO
Epidemiological situation of taeniasis in Mongolia was assessed based on mitochondrial DNA identification of the parasite species. Multiplex PCR was used on a total of 194 proglottid specimens of Taenia species and copro-PCR and loop-mediated isothermal amplification (LAMP) assays were utilized for detection of copro-DNA of 37 fecal samples from taeniasis patients submitted to the Mongolian National Center for Communicable Diseases (NCCD) from 2002 to 2012. In addition, 4 out of 44 calcified cysts in beef kept in formalin since 2003 were evaluated for histopathological confirmation of cattle cysticercosis. All proglottid specimens and stool samples were confirmed to be Taenia saginata by multiplex PCR and by copro-PCR and LAMP, respectively. Cysts collected from cattle were morphologically confirmed to be metacestodes of Taenia species. T. saginata taeniasis was identified from almost all ages from a 2-year-old boy up to a 88-year-old woman and most prominently in 15-29 age group (37%, 74/198) followed by 30-44 age group (34.8%, 69/198 ) from 15 of Mongolia's 21 provinces, while cattle cysticerci were found from 12 provinces. The highest proportion of taeniasis patients was in Ulaanbaatar, the capital of Mongolia.
Assuntos
Cisticercose/epidemiologia , DNA de Helmintos/genética , DNA Mitocondrial/genética , Taenia saginata/genética , Teníase/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Bovinos/parasitologia , Criança , Pré-Escolar , Cisticercose/parasitologia , Fezes/parasitologia , Feminino , Geografia , Humanos , Masculino , Carne/parasitologia , Pessoa de Meia-Idade , Mitocôndrias/genética , Mongólia/epidemiologia , Doenças Negligenciadas/epidemiologia , Técnicas de Amplificação de Ácido Nucleico/veterinária , Inquéritos e Questionários , Taenia solium/genética , Teníase/parasitologia , Adulto JovemRESUMO
OBJECTIVE: Low-density lipoprotein receptor (LDLR) is degraded by inducible degrader of LDLR (Idol) and protein convertase subtilisin/kexin type 9 (PCSK9), thereby regulating circulating LDL levels. However, it remains unclear whether, and if so how, these LDLR degraders affect each other. We therefore investigated effects of liver-specific expression of Idol on LDL/PCSK9 metabolism in mice and hamsters. APPROACH AND RESULTS: Injection of adenoviral vector expressing Idol (Ad-Idol) induced a liver-specific reduction in LDLR expression which, in turn, increased very-low-density lipoprotein/LDL cholesterol levels in wild-type mice because of delayed LDL catabolism. Interestingly, hepatic Idol overexpression markedly increased plasma PCSK9 levels. In LDLR-deficient mice, plasma PCSK9 levels were already elevated at baseline and unchanged by Idol overexpression, which was comparable with the observation for Ad-Idol-injected wild-type mice, indicating that Idol-induced PCSK9 elevation depended on LDLR. In wild-type mice, but not in LDLR-deficient mice, Ad-Idol enhanced hepatic PCSK9 expression, with activation of sterol regulatory element-binding protein 2 and subsequently increased expression of its target genes. Supporting in vivo findings, Idol transactivated PCSK9/LDLR in sterol regulatory element-binding protein 2/LDLR-dependent manners in vitro. Furthermore, an in vivo kinetic study using (125)I-labeled PCSK9 revealed delayed clearance of circulating PCSK9, which could be another mechanism. Finally, to extend these findings into cholesteryl ester transfer protein-expressing animals, we repeated the above in vivo experiments in hamsters and obtained similar results. CONCLUSIONS: A vicious cycle in LDLR degradation might be generated by PCSK9 induced by hepatic Idol overexpression via dual mechanisms: sterol regulatory element-binding protein 2/LDLR. Furthermore, these effects would be independent of cholesteryl ester transfer protein expression.
Assuntos
Fígado/metabolismo , Pró-Proteína Convertases/sangue , Receptores de LDL/fisiologia , Serina Endopeptidases/sangue , Transdução de Sinais , Proteína de Ligação a Elemento Regulador de Esterol 2/fisiologia , Ubiquitina-Proteína Ligases/fisiologia , Animais , Proteínas de Transferência de Ésteres de Colesterol/fisiologia , Cricetinae , Células Hep G2 , Humanos , Lipoproteínas LDL/metabolismo , Receptores X do Fígado , Mesocricetus , Camundongos , Camundongos Endogâmicos C57BL , Receptores Nucleares Órfãos/fisiologia , Pró-Proteína Convertase 9 , Pró-Proteína Convertases/fisiologia , Serina Endopeptidases/fisiologiaRESUMO
We herein describe the establishment of single hepatic lesions of Echinococcus multilocularis in rats. A 3mm incision was made on the liver with a surgical knife, and one small round vesicle of E. multilocularis (between 1 × 1 mm and <2 × 2 mm in diameter) was transplanted into the incision and covered with absorbable hemostat gauze. The presence and growth of the transplanted vesicle was monitored for 12 weeks using magnetic resonance imaging (MRI). Hepatic lesions, the metacestode of this parasite were confirmed in 12 of 17 infected rats (70.6%) by MRI and macroscopic examinations. The average size of the metacestodes with brood capsules at 12 weeks after the experimental transplantation of a single vesicle was 6.1 ± 2.5 mm × 4.4 ± 1.5mm. The smallest size of the metacestodes detected by MRI was approximately 3 × 3 mm. This new approach of establishing single hepatic metacestodes of E. multilocularis in experimental animals is expected to be useful for analyzing the immune-pathological mechanisms of hepatic AE.
Assuntos
Modelos Animais de Doenças , Equinococose Hepática/parasitologia , Echinococcus multilocularis , Fígado/parasitologia , Animais , Feminino , Imageamento por Ressonância Magnética , Ratos , Organismos Livres de Patógenos EspecíficosRESUMO
The small intestines of 420 wild canids (111 corsac foxes, 191 red foxes and 118 wolves) from Mongolia, were examined for adult worms of the genus Echinococcus. The Mongolian genotype of Echinococcus multilocularis was found in fifteen red foxes and four wolves, whereas two genotypes (G6/7 and G10) of Echinococcus canadensis were found in two and three wolves, respectively. No adult Echinococcus worms were found in the corsac foxes examined. The genotypes of E. multilocularis and E. canadensis are discussed in terms of host specificity and distribution in Mongolia. The importance of wolves in the completion of the life cycle of Echinococcus spp. is also discussed.
Assuntos
DNA de Helmintos/genética , DNA Mitocondrial/genética , Equinococose/veterinária , Echinococcus/genética , Complexo IV da Cadeia de Transporte de Elétrons/genética , Raposas/parasitologia , Filogenia , Lobos/parasitologia , Animais , DNA de Helmintos/classificação , DNA Mitocondrial/classificação , Equinococose/epidemiologia , Equinococose/parasitologia , Echinococcus/classificação , Complexo IV da Cadeia de Transporte de Elétrons/classificação , Fezes/parasitologia , Genoma Mitocondrial , Genótipo , Especificidade de Hospedeiro , Intestino Delgado/parasitologia , Epidemiologia Molecular , Mongólia/epidemiologia , Especificidade da EspécieRESUMO
Alveolar echinococcosis (AE) is one of the most lethal zoonotic parasitic infections. The diagnosis is based on the combination of the abdominal imaging including CT, MRI and PET, and serology. To develop a new diagnostic tool for AE with urine as samples, mouse-Echinococcus multilocularis (Em) model and then human cases were studied. The antibody levels of urine and serum samples from the infected mice and AE cases were well correlated with each other. The sensitivity and specificity of the method with urine were 91% and 98%, respectively, when IgG4 to crude Em was examined. Comparing with serum samples, the collection of urine is easier and safer and the urine diagnostic tool makes surveys of this silent disease easier.
Assuntos
Anticorpos Anti-Helmínticos , Equinococose Hepática/diagnóstico , Equinococose Pulmonar/diagnóstico , Equinococose/diagnóstico , Echinococcus multilocularis/imunologia , Animais , Anticorpos Anti-Helmínticos/sangue , Anticorpos Anti-Helmínticos/imunologia , Anticorpos Anti-Helmínticos/urina , Equinococose/parasitologia , Equinococose Hepática/parasitologia , Equinococose Pulmonar/parasitologia , Ensaio de Imunoadsorção Enzimática/métodos , Humanos , Camundongos , Sensibilidade e Especificidade , ZoonosesRESUMO
Stearoyl-coenzyme A desaturase 1 (SCD1) is the rate-limiting enzyme in the synthesis of monounsaturated fatty acids. However, the impact of SCD1 on atherosclerosis remains unclear. The aim of this study was to determine whether SCD1 affects macrophage reverse cholesterol transport (RCT) in mice. Compared to the control, adenoviral-mediated SCD1 overexpression in RAW264.7 macrophages increased cholesterol efflux to HDL, but not to apoA-I, without clear changes in ABCA1, ABCG1 and SR-BI expressions. While knockdown of ABCG1 and SR-BI did not affect the SCD1-induced cholesterol efflux to HDL, SCD1-overexpressing macrophages promoted the formation of both normal- and large-sized HDL in media, accompanying increased apolipoprotein A-I levels in HDL fractions. Transformation to larger particles of HDL was independently confirmed by nuclear magnetic resonance-based lipoprotein analysis. Interestingly, media transfer assays revealed that HDL generated by SCD1 had enhanced cholesterol efflux potential, indicating that SCD1 transformed HDL to a more anti-atherogenic phenotype. To study macrophage RCT in vivo, (3)H-cholesterol-labeled RAW264.7 cells overexpressing SCD1 or the control were intraperitoneally injected into mice. Supporting the in vitro data, injection of SCD1-macrophages resulted in significant increases in (3)H-tracer in plasma, liver, and feces compared to the control. Moreover, there was a shift towards larger particles in the (3)H-tracer distribution of HDL fractions obtained from the mice. In conclusion, macrophage-specific SCD1 overexpression promotes overall RCT through increased cholesterol efflux to HDL, suggesting that macrophage SCD1 achieves an anti-atherogenic effect by enhancing RCT.
Assuntos
Colesterol/metabolismo , Regulação Enzimológica da Expressão Gênica , Lipoproteínas HDL/metabolismo , Macrófagos/enzimologia , Estearoil-CoA Dessaturase/biossíntese , 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/genética , Transportadores de Cassetes de Ligação de ATP/metabolismo , Animais , Aterosclerose/enzimologia , Aterosclerose/genética , Aterosclerose/patologia , Aterosclerose/terapia , Transporte Biológico Ativo/genética , Linhagem Celular , Colesterol/genética , Humanos , Lipoproteínas/genética , Lipoproteínas/metabolismo , Lipoproteínas HDL/genética , Macrófagos/patologia , Camundongos , Estearoil-CoA Dessaturase/genéticaRESUMO
SUMMARY Cysticercosis caused by infection with the larval stage of Taenia solium is an important cause of neurological disease worldwide and immunodiagnosis is important for the control and elimination of cysticercosis. In the present study, we established a simple and reliable preparation of immunodiagnostic low-molecular-weight antigens (LMWAgs) from T. solium cyst fluids by a cation-exchange chromatography (CEC). Banding patterns of LMWAgs on SDS-PAGE were different between isolates from Ecuador and China. All cysticercosis patient sera and some echinococcosis patient sera recognized both LMWAgs by enzyme-linked immunosorbent assay (ELISA), but sera from healthy persons were not positive. There was no statistical difference in immunodiagnostic performance of LMWAgs prepared from different geographical isolates. These results indicated that these novel immunodiagnostic antigen preparations could contribute the control and prevention of cysticercosis in endemic areas, especially developing countries.
Assuntos
Antígenos de Helmintos/análise , Cisticercose/diagnóstico , Cisticercose/veterinária , Imunoensaio , Doenças dos Suínos/diagnóstico , Taenia solium/isolamento & purificação , Animais , China , Cromatografia por Troca Iônica , Cisticercose/imunologia , Cisticercose/parasitologia , Países em Desenvolvimento , Equador , Humanos , Larva/química , Larva/imunologia , Peso Molecular , Kit de Reagentes para Diagnóstico , Suínos , Doenças dos Suínos/imunologia , Doenças dos Suínos/parasitologia , Taenia solium/química , Taenia solium/imunologiaRESUMO
ATP-binding cassette transporters (ABC) A1 and G1 are key molecules in cholesterol efflux from macrophages, which is an initial step of reverse cholesterol transport (RCT), a major anti-atherogenic property of high-density lipoprotein (HDL). Astaxanthin is one of the naturally occurring carotenoids responsible for the pink-red pigmentation in a variety of living organisms. Although astaxanthin is known to be a strong antioxidant, it remains unclear through what mechanism of action it affects cholesterol homeostasis in macrophages. We therefore investigated the effects of astaxanthin on cholesterol efflux and ABCA1/G1 expressions in macrophages. Astaxanthin enhanced both apolipoprotein (apo) A-I- and HDL-mediated cholesterol efflux from RAW264.7 cells. In supporting these enhanced cholesterol efflux mechanisms, astaxanthin promoted ABCA1/G1 expression in various macrophages. In contrast, peroxisome proliferator-activated receptor γ, liver X receptor (LXR) α and LXRß levels remained unchanged by astaxanthin. An experiment using actinomycin D demonstrated that astaxanthin transcriptionally induced ABCA1/G1 expression, and oxysterol depletion caused by overexpression of cholesterol sulfotransferase further revealed that these inductions in ABCA1/G1 were independent of LXR-mediated pathways. Finally, we performed luciferase assays using human ABCA1/G1 promoter-reporter constructs to reveal that astaxanthin activated both promoters irrespective of the presence or absence of LXR-responsive elements, indicating LXR-independence of these activations. In conclusion, astaxanthin increased ABCA1/G1 expression, thereby enhancing apoA-I/HDL-mediated cholesterol efflux from the macrophages in an LXR-independent manner. In addition to the anti-oxidative properties, the potential cardioprotective properties of astaxanthin might therefore be associated with an enhanced anti-atherogenic function of HDL.
Assuntos
Transportadores de Cassetes de Ligação de ATP/genética , Colesterol/metabolismo , Expressão Gênica/efeitos dos fármacos , Lipoproteínas/genética , Macrófagos/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/fisiologia , Animais , Antioxidantes , Apolipoproteína A-I/efeitos dos fármacos , Apolipoproteína A-I/fisiologia , Cardiotônicos , Linhagem Celular , Lipoproteínas/fisiologia , Lipoproteínas HDL/efeitos dos fármacos , Lipoproteínas HDL/fisiologia , Receptores X do Fígado , Macrófagos/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL , Receptores Nucleares Órfãos/fisiologia , Xantofilas/farmacologiaRESUMO
ABC transporter G1 (ABCG1) plays a pivotal role in HDL-mediated cholesterol efflux and atherogenesis. We investigated whether, and how, retinoic acid receptors (RARs) regulate ABCG1 expression in macrophages. All-trans retinoic acid (ATRA), an RAR ligand, increased ABCG1 protein levels and apoA-I/HDL-mediated cholesterol efflux from the macrophages. Both ATRA and other RAR agonists, TTNPB and Am580, increased major transcripts driven by promoter B upstream of exon 5, though minor transcripts driven by promoter A upstream of exon 1 were only increased by ATRA. The stimulatory effects of ATRA on ABCG1 expression were completely abolished in the presence of RAR/RXR antagonists but were only partially canceled in the presence of an LXR antagonist. Adenovirus with overexpressed oxysterol sulfotransferase abolished the LXR pathway, as previously reported, and ATRA-responsiveness in ABCA1/ABCG1 expressions were respectively attenuated by 38 and 22% compared to the control virus. Promoter assays revealed that ABCG1 levels were regulated more by promoter B than promoter A, and ATRA activated promoter B in a liver X receptor-responsive element (LXRE)-dependent manner. Further, LXRE-B in intron 7, but not LXRE-A in intron 5, enhanced ATRA responsiveness under overexpression of all RAR isoforms-RARα/ß/γ. In contrast, the activation of promoter B by TTNPB depended on LXRE-B and RARα, but not on RARß/γ. Finally, chromatin immunoprecipitation and gel-shift assays revealed a specific and direct repeat 4-dependent binding of RARα to LXRE-B. In conclusion, RAR ligands increase ABCA1/G1 expression and apoA-I/HDL-mediated cholesterol efflux from macrophages, and modulate ABCG1 promoter activity via LXRE-dependent mechanisms.
Assuntos
Transportadores de Cassetes de Ligação de ATP/metabolismo , Macrófagos/efeitos dos fármacos , Receptores do Ácido Retinoico/agonistas , Tretinoína/farmacologia , 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/genética , Animais , Benzoatos/farmacologia , Transporte Biológico/efeitos dos fármacos , Western Blotting , Células COS , Linhagem Celular , Chlorocebus aethiops , Colesterol/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Células HEK293 , Humanos , Receptores X do Fígado , Macrófagos/citologia , Macrófagos/metabolismo , Modelos Genéticos , Receptores Nucleares Órfãos/agonistas , Receptores Nucleares Órfãos/genética , Receptores Nucleares Órfãos/metabolismo , Regiões Promotoras Genéticas/genética , Ligação Proteica/efeitos dos fármacos , Receptores do Ácido Retinoico/genética , Receptores do Ácido Retinoico/metabolismo , Elementos de Resposta/genética , Receptores X de Retinoides/agonistas , Receptores X de Retinoides/genética , Receptores X de Retinoides/metabolismo , Retinoides/farmacologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/efeitos dos fármacos , Tetra-Hidronaftalenos/farmacologiaRESUMO
Taenia solium is a zoonotic cestode that causes taeniasis and cysticercosis in humans. The parasite is traditionally found in developing countries where undercooked pork is consumed under poor sanitary conditions and/or as part of traditional food cultures. However, the recent increase in international tourism and immigration is spreading the disease into non-endemic developed countries such as the United States. Although there has been concern that the number of cysticercosis cases is increasing in Japan, the current situation is not clear. This is largely because taeniasis and cysticercosis are not notifiable conditions in Japan and because there have been no comprehensive reviews of T. solium infections in Japan conducted in the last 15 years. Herein, we provide an overview of the status of T. solium infection in Japan over the past 35 years and point out the potential risks to Japanese society.
Assuntos
Anti-Helmínticos/uso terapêutico , Taenia solium/isolamento & purificação , Teníase/parasitologia , Adulto , Albendazol/uso terapêutico , Animais , Cisticercose/tratamento farmacológico , Cisticercose/parasitologia , Diatrizoato de Meglumina/uso terapêutico , Feminino , Humanos , Incidência , Japão , Masculino , Praziquantel/uso terapêutico , Taenia solium/genética , Teníase/tratamento farmacológicoRESUMO
An ocular cysticercosis case of a nine-year-old Balinese girl in Indonesia is reported. She presented with redness and pain in the left eye and showed a cysticercus in the anterior chamber in December 2010. Morphological feature of the cysticercus removed from the anterior chamber indicated that it was an immature cysticercus of Taenia species with no hooklets. However, mitochondrial DNA analysis using a piece of histopathological specimen revealed it a cysticercus of Taenia solium Asian genotype. Serology by immunoblot and ELISA highly specific to cysticercosis was negative.
Assuntos
Cisticercose/diagnóstico , Cysticercus/isolamento & purificação , Infecções Oculares Parasitárias/diagnóstico , Taenia solium/isolamento & purificação , Animais , Câmara Anterior/parasitologia , Câmara Anterior/cirurgia , Criança , Cisticercose/parasitologia , Cisticercose/cirurgia , Cysticercus/citologia , Cysticercus/genética , DNA Mitocondrial/química , DNA Mitocondrial/genética , Olho/parasitologia , Olho/patologia , Infecções Oculares Parasitárias/parasitologia , Infecções Oculares Parasitárias/cirurgia , Feminino , Humanos , Indonésia , Análise de Sequência de DNA , Testes Sorológicos , Taenia solium/citologia , Taenia solium/genéticaRESUMO
OBJECTIVE: ATP-binding cassette transporter A1 (ABCA1) and ABCG1 are key molecules in an initial step of reverse cholesterol transport (RCT), a major antiatherogenic property of high-density lipoprotein (HDL). The ubiquitin-proteasome system (UPS) mediates nonlysosomal pathways for protein degradation and is known to be involved in atherosclerosis. However, little is known about the effects of the UPS on these molecules and overall RCT. We therefore investigated whether UPS inhibition affects ABCA1/G1 expression in macrophages and RCT in vitro and in vivo. METHODS AND RESULTS: Various proteasome inhibitors increased ABCA1/G1 expression in macrophages, translating into enhanced apolipoprotein A-I- and HDL-mediated cholesterol efflux from macrophages. ABCA1 and ABCG1 were found to undergo polyubiquitination in the macrophages and HEK293 cells overexpressing these proteins, and pulse-chase analysis revealed that proteasome inhibitors inhibited ABCA1/G1 protein degradation. In in vivo experiments, the proteasome inhibitor bortezomib increased ABCA1/G1 protein levels in mouse peritoneal macrophages, and RCT assays showed that it significantly increased the fecal (54% increase compared with saline) and plasma (23%) appearances of the tracer derived from intraperitoneally injected (3)H-cholesterol-labeled macrophages. CONCLUSIONS: The present study provided evidence that the UPS is involved in ABCA1/G1 degradation, thereby affecting RCT in vivo. Therefore, specific inhibition of the UPS pathway might lead to a novel HDL therapy that enhances RCT.
Assuntos
Transportadores de Cassetes de Ligação de ATP/fisiologia , Colesterol/metabolismo , Lipoproteínas/fisiologia , Macrófagos/metabolismo , Complexo de Endopeptidases do Proteassoma/fisiologia , 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/análise , Animais , Apolipoproteína A-I/fisiologia , Ácidos Borônicos/farmacologia , Bortezomib , Células Cultivadas , Células Hep G2 , Humanos , Lipoproteínas/análise , Lipoproteínas HDL/fisiologia , Camundongos , Fosforilação , Inibidores de Proteassoma , Pirazinas/farmacologia , Ubiquitina-Proteína Ligases/fisiologia , UbiquitinaçãoRESUMO
OBJECTIVE: Pioglitazone, a peroxisome proliferator-activated receptor γ (PPARγ) agonist, reportedly reduces cardiovascular events in diabetic patients. ATP cassette binding transporters (ABC) A1 and G1 are pivotal molecules for cholesterol efflux (ChE) from macrophages and high density-lipoprotein biogenesis, and the A1 transporter is regulated by a PPARγ-liver receptor X (LXR) pathway. Also, pioglitazone induces ABCG1 expression, though the exact mechanism remains unclear. We therefore investigated the effects of pioglitazone on ABCA1/G1 expression in vitro and ex vivo. METHODS: The effects of pioglitazone on ChE and ABCA1/G1 expressions in macrophages were assessed. Then, mRNA was quantified in macrophages when PPARγ/LXR inhibition by siRNA or overexpression of oxysterol sulfotransferase was performed. ABCA1/G1 promoter activity with mutated LXR-responsive elements was also measured. As an ex vivo study, 15 type 2 diabetic patients were administered pioglitazone or placebo, and ChE assays and protein expressions were determined using macrophages cultured with the corresponding sera. RESULTS: Pioglitazone increased LXRα/ABCA1/G1 expressions, which enhanced ChE from macrophages. Inhibition of PPARγ/LXR pathways revealed that LXR was primarily involved in pioglitazone's transactivation of ABCA1 but only partially involved for ABCG1. Promoter assays showed that ABCG1 was regulated more by the promoter in intron 4 than that upstream of exon 1 but both promoters were responsive to LXR activation. Sera obtained after pioglitazone treatment promoted ChE and ABCA1/G1 expressions in macrophages. CONCLUSION: Pioglitazone enhanced ChE from macrophages by increasing ABCA1/G1 in LXR-dependent and -independent manners. Our comparable in vitro and ex vivo results shed new light on pioglitazone's novel anti-atherogenic property.
Assuntos
Transportadores de Cassetes de Ligação de ATP/biossíntese , Colesterol/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Hipoglicemiantes/farmacologia , Macrófagos/fisiologia , Receptores Nucleares Órfãos/biossíntese , PPAR gama/metabolismo , Tiazolidinedionas/farmacologia , Transportador 1 de Cassete de Ligação de ATP , Membro 1 da Subfamília G de Transportadores de Cassetes de Ligação de ATP , Células Cultivadas , Células HEK293 , Humanos , Receptores X do Fígado , Macrófagos/efeitos dos fármacos , Pioglitazona , Interferência de RNARESUMO
AIM: Reverse cholesterol transport (RCT) is a critical mechanism for the anti-atherogenic property of HDL. The inhibitory effect of the sulfonylurea agent (SUA) glibenclamide on ATP binding-cassette transporter (ABC) A1 may decrease HDL function but it remains unclear whether it attenuates RCT in vivo. We therefore investigated how the SUAs glibenclamide and glimepiride affected the functionality of ABCA1/ABCG1 and scavenger receptor class B type I (SR-BI) expression in macrophages in vitro and overall RCT in vivo. METHODS: RAW264.7, HEK293 and BHK-21 cells were used for in vitro studies. To investigate RCT in vivo, 3H-cholesterol-labeled and acetyl LDL-loaded RAW264.7 cells were injected into mice. RESULTS: High dose (500µM) of glibenclamide inhibited ABCA1 function and apolipoprotein A-I (apoA-I)-mediated cholesterol efflux, and attenuated ABCA1 expression. Although glimepiride maintained apoA-I-mediated cholesterol efflux from RAW264.7 cells, like glibenclamide, it inhibited ABCA1-mediated cholesterol efflux from transfected HEK293 cells. Similarly, the SUAs inhibited SR-BI-mediated cholesterol efflux from transfected BHK-21 cells. High doses of SUAs increased ABCG1 expression in RAW264.7 cells, promoting HDL-mediated cholesterol efflux in an ABCG1-independent manner. Low doses (0.1-100 µM) of SUAs did not affect cholesterol efflux from macrophages despite dose-dependent increases in ABCA1/G1 expression. Furthermore, they did not change RCT or plasma lipid levels in mice. CONCLUSION: High doses of SUAs inhibited the functionality of ABCA1/SR-BI, but not ABCG1. At lower doses, they had no unfavorable effects on cholesterol efflux or overall RCT in vivo. These results indicate that SUAs do not have adverse effects on atherosclerosis contrary to previous findings for glibenclamide.