Disfunción del transportador del surfactante pulmonar ABCA3: reporte de un caso peruano / Surfactant ABCA3 transporter dysfunction: a case report from Peru

Resumen Introducción: Los trastornos genéticos que afectan la homeostasis del surfactante pulmonar son una causa importante del síndrome de dificultad respiratoria en el recién nacido a término y de enfermedad pulmonar intersticial difusa en niños. El transportador ABCA3 (ATP binding cassette A3) interviene en la producción normal del surfactante que recubre el interior de las paredes alveolares y funciona como agente tensioactivo. Caso clínico: Recién nacido a término que presentó dificultad respiratoria a los 3 días de vida y requirió ventilación mecánica. Los estudios para determinar otras causas de enfermedad pulmonar fueron negativos. Se realizó una biopsia de pulmón para realizar estudios de microscopía óptica y microscopía electrónica. Esta última mostró pequeños cuerpos lamelares anómalos, además de condensaciones electrodensas periféricas, características de las mutaciones del transportador ABCA3. Se inició tratamiento con pulsos de metilprednisolona, hidroxicloroquina, azitromicina y corticoides inhalados a dosis altas, y la respuesta clínica y radiológica fue favorable durante el seguimiento. Conclusiones: La correlación de las características clínicas y de las imágenes (tomografía y microscopía electrónica) puede ser útil para el diagnóstico de la disfunción del surfactante pulmonar, especialmente en los países de bajos y medianos recursos que no disponen de estudios genéticos para determinar las diferentes mutaciones del transportador ABCA3. Este es uno de los primeros casos reportados en Perú con respuesta adecuada al tratamiento y evolución favorable durante el seguimiento.

Abstract Background: Genetic disorders affecting pulmonary surfactant homeostasis are a major cause of respiratory distress syndrome in full-term newborn and childhood interstitial lung disease. The ABCA3 transporter (ATP binding cassette A3) intervenes in the normal production of surfactant that covers the interior of alveolar walls and plays a fundamental role as a surfactant. Case report: Male term newborn who presented respiratory distress 3 days after birth and required mechanical ventilation. Studies to determine other causes of lung disease were negative. Lung biopsy was performed for the study with light microscopy and electron microscopy. Electron microscopy showed small abnormal lamellar bodies in addition to peripheral electrodense condensations characteristic of ABCA3 transporter mutation. Treatment was started with pulses of methylprednisolone, hydroxychloroquine, azithromycin, and high-dose inhaled corticosteroids, finding a favorable clinical and radiological response to follow-up. Conclusions: Correlation of clinical characteristics and images (tomography and electron microscopy) can be useful for the diagnosis of lung surfactant dysfunction, especially in low and medium-income countries where genetic studies to determine the different ABCA3 transporter mutations are not available. This is one of the first cases reported in Peru with an adequate response to treatment and favorable evolution to follow-up.

El intersticio pulmonar y sus enfermedades en la infancia. Deficiencia de ABCA3. Seguimiento durante doce años. Perspectivas ¿Un nuevo paradigma genético? / The pulmonary interstitium and its diseases in childhood. ABCA3 deficiency. Follow-up for 12 years. Perspectives. A new genetic paradigm?

Introducción. Sobre la base de un caso clínico, se presenta la descripción del cuadro intersticial por deficiencia de ABCA3, de una paciente de catorce años de edad, en seguimiento durante doce años. Método. Evaluación clínica con extensos estudios para descartar otras patologías semejantes. El diagnóstico definitivo fue determinado por el estudio genético para deficiencias de ABCA3 y otros defectos genéticos realizados por el Dr. Larry Nogee, Hospital Johns Hopkins, EE. UU. Objetivos. Describir detalladamente la evolución de la paciente durante doce años, con énfasis en los estudios anteriormente mencionados. Sugerir la presencia de un cambio de paradigma pronóstico en lo que se conocía sobre la evolución de esta enfermedad intersticial pulmonar grave, tratar de mejorar la calidad de vida y posiblemente el pronóstico. Presentar los hallazgos de genética, anatomía patológica y radiología en consultas y evaluaciones por centros de referencia. Resultados. Realizado su diagnóstico de deficiencia genética de ABCA3, presentamos su seguimiento actualizado hasta el año 2020. Esta debe ser sospechada en niños pequeños desde el nacimiento y durante los primeros años ante la persistencia de cuadros pulmonares crónicos con desaturación de oxígeno e imágenes tomográficas que sugieren cuadro intersticial. Se decidió tratar el cuadro en los años 2019-2020, durante seis meses, según bibliografía y consultas con centros de referencia en los Estados Unidos, con la finalidad de determinar la posible mejoría de su patología y decidir la continuación o suspensión de la medicación. Se usaron pulsos con metilprednisolona- hidroxicloroquina y azitromicina. Se logró mantener estable su función pulmonar y mejorar notablemente su calidad de vida. (AU)

Introduction. A clinical case diagnosed with ABCA3 deficiency is described. Patient is now fourteen years old. She´s being followed up since she was two years old. Methodology. clinical follow ­ up with extensive studies to rule out other similar pathologies. Final diagnosis was done through genetic studies done at Johns Hopkins Hospital by Nogee LM. Objective. To present a detailed evolution description of twelve years' follow-up with the support of the aforementioned studies, to suggest a change in diagnostic ­ prognostic paradigm on what was known of mortality in this severe pulmonary interstitial pathology to improve life quality and possibly prognosis. Present the findings of genetics, pathological anatomy and radiology in consultations and evaluations by reference centers. Results. Having made her diagnosis of genetic ABCA3 deficiency, we present her up dated follow-up until 2020. This should be suspected in young children from birth and during the first years due to the persistence of chronic pulmonary symptoms with oxygen desaturation and tomographic images that suggest interstitial symptoms. It was decided to treat the condition in the years 2019-2020, for six months, according to the bibliography and consultations with reference centers in the United States, in order to determine the possible improvement of her pathology and decide to continue or suspend the medication. Pulses with methylprednisolone hydroxychloroquine and azithromycin were used. Her lung function was stable and her quality of life significantly improved. (AU)

Absorption mechanism of three curcumin constituents through in situ intestinal perfusion method

This study aimed to investigate the absorption mechanism of three curcumin constituents in rat small intestines. Self-emulsification was used to solubilize the three curcumin constituents, and the rat in situ intestinal perfusion method was used to study factors on drug absorption, including drug mass concentration, absorption site, and the different types and concentrations of absorption inhibitors. Within the scope of experimental concentrations, three curcumin constituents were absorbed in rat small intestines through the active transport mechanism.

The effect of smoking on myeloid-related protein-8 and myeloid-related protein-14

Abstract The aim of this study was to determine the myeloid-related protein-8 and myeloid-related protein-14 levels in the gingival crevicular fluid of smoker patients with generalized aggressive periodontitis (SAgP), smoker patients with chronic periodontitis (SCP), smoker patients with gingivitis (SG-smoker control), non-smoker patients with generalized aggressive periodontitis (AgP), non-smoker patients with chronic periodontitis (CP), and non-smoker patients with gingivitis (G-non-smoker control). The periodontal statuses of the patients were determined by periodontal clinical measurements and radiographical evaluations. The levels of myeloid-related protein-8 and myeloid-related protein-14 in the gingival crevicular fluid were assessed using enzyme-linked immuno sorbent assay. The myeloid-related protein-8 and myeloid-related protein-14 levels in the gingival crevicular fluid of patients with generalized aggressive periodontitis (non-smoker and smoker) were found to be statistically higher than patients with chronic periodontitis (non-smoker and smoker) and patients with gingivitis (non-smoker and smoker). Myeloid-related protein-8 and myeloid-related protein-14 levels of non-smokers were significantly higher than smokers in all types of periodontitis and gingivitis. The decreased myeloid-related protein-8 and myeloid-related protein-14 level could have prevented the haemostasis of calcium which plays a significant role in the migration of neutrophiles. Smoking affects myeloid-related protein-8 and myeloid-related protein-14 levels and may inhibit the antimicrobial efficiency against microorganisms. Due to these reasons smoker generalized aggressive periodontitis patients need to be treated in detail and their maintenance durations should be shortened.

Gene expression profile of ABC transporters and cytotoxic effect of ibuprofen and acetaminophen in an epithelial ovarian cancer cell line in vitro / Perfil da expressão gênica dos transportadores ABC e efeito citotóxico do ibuprofeno e acetaminofen em uma linhagem celular de câncer epitelial de ovário in vitro

PURPOSES: To determine the basic expression of ABC transporters in an epithelial ovarian cancer cell line, and to investigate whether low concentrations of acetaminophen and ibuprofen inhibited the growth of this cell line in vitro. METHODS: TOV-21 G cells were exposed to different concentrations of acetaminophen (1.5 to 15 μg/mL) and ibuprofen (2.0 to 20 μg/mL) for 24 to 48 hours. The cellular growth was assessed using a cell viability assay. Cellular morphology was determined by fluorescence microscopy. The gene expression profile of ABC transporters was determined by assessing a panel including 42 genes of the ABC transporter superfamily. RESULTS: We observed a significant decrease in TOV-21 G cell growth after exposure to 15 μg/mL of acetaminophen for 24 (p=0.02) and 48 hours (p=0.01), or to 20 μg/mL of ibuprofen for 48 hours (p=0.04). Assessing the morphology of TOV-21 G cells did not reveal evidence of extensive apoptosis. TOV-21 G cells had a reduced expression of the genes ABCA1, ABCC3, ABCC4, ABCD3, ABCD4 and ABCE1 within the ABC transporter superfamily. CONCLUSIONS: This study provides in vitro evidence of inhibitory effects of growth in therapeutic concentrations of acetaminophen and ibuprofen on TOV-21 G cells. Additionally, TOV-21 G cells presented a reduced expression of the ABCA1, ABCC3, ABCC4, ABCD3, ABCD4 and ABCE1 transporters. .

OBJETIVOS: Determinar a expressão básica dos transportadores ABC em uma linhagem celular do câncer epitelial de ovário, e investigar se o acetaminofen e o ibuprofeno em baixas concentrações são capazes de inibir o crescimento desta linhagem celular in vitro. MÉTODOS: A linhagem celular TOV-21 G foi exposta a diferentes concentrações de acetaminofen (1,5 a 15 µg/mL) e ibuprofeno (2,0 a 20 µg/mL), de 24 a 48 horas. O crescimento celular foi avaliado utilizando-se um ensaio de viabilidade celular. A morfologia celular foi determinada por meio da microscopia de fluorescência. O perfil de expressão gênica foi estabelecido por um painel de 42 genes da superfamília de transportadores ABC. RESULTADOS: Observou-se um decréscimo significativo no crescimento das células TOV-21 G expostas a 15 µg/mL de acetaminofen durante 24 (p=0,02) e 48 horas (p=0,01), ou a 20 µg/mL de ibuprofeno por 48 horas (p=0,04). Ao avaliar a morfologia das células cultivadas, não foi observada evidência de apoptose extensiva. A linhagem de células estudada subexpressa os genes de ABCA1, ABCC3, ABCC4, ABCD3, ABCD4 e ABCE1 na superfamília de transportadores ABC. CONCLUSÕES: Este estudo fornece evidências in vitro referentes aos efeitos inibidores do crescimento de concentrações terapêuticas do acetaminofen e ibuprofeno na linhagem celular testada. Além disso, as células TOV-21 G apresentaram uma expressão reduzida de genes dos transportadores ABCA1, ABCC3, ABCC4, ABCD3, ABCD4 e ABCE1. .

A novel ABCG-like transporter of Trypanosoma cruzi is involved in natural resistance to benznidazole

Benznidazole (BZ) is one of the two drugs used for Chagas disease treatment. Nevertheless therapeutic failures of BZ have been reported, which were mostly attributed to variable drug susceptibility among Trypanosoma cruzi strains. ATP-binding cassette (ABC) transporters are involved in a variety of translocation processes and some members have been implicated in drug resistance. Here we report the characterisation of the first T. cruzi ABCG transporter gene, named TcABCG1, which is over-expressed in parasite strains naturally resistant to BZ. Comparison of TcABCG1 gene sequence of two TcI BZ-resistant strains with CL Brener BZ-susceptible strain showed several single nucleotide polymorphisms, which determined 11 amino acid changes. CL Brener transfected with TcI transporter genes showed 40-47% increased resistance to BZ, whereas no statistical significant increment in drug resistance was observed when CL Brener was transfected with the homologous gene. Only in the parasites transfected with TcI genes there was 2-2.6-fold increased abundance of TcABCG1 transporter protein. The analysis in wild type strains also suggests that the level of TcABCG1 transporter is related to BZ natural resistance. The characteristics of untranslated regions of TcABCG1 genes of BZ-susceptible and resistant strains were investigated by computational tools.

Evaluation of the role of ATP-binding cassette transporters as a defence mechanism against temephos in populations of Aedes aegypti

The role of ATP-binding cassette (ABC) transporters in the efflux of the insecticide, temephos, was assessed in the larvae of Aedes aegypti. Bioassays were conducted using mosquito populations that were either susceptible or resistant to temephos by exposure to insecticide alone or in combination with sublethal doses of the ABC transporter inhibitor, verapamil (30, 35 and 40 μM). The best result in the series was obtained with the addition of verapamil (40 μM), which led to a 2x increase in the toxicity of temephos, suggesting that ABC transporters may be partially involved in conferring resistance to the populations evaluated.

Effects of R219K polymorphism of ATP-binding cassette transporter 1 gene on serum lipids ratios induced by a high-carbohydrate and low-fat diet in healthy youth

BACKGROUND: Diets are the important players in regulating plasma lipid profiles. And the R219K polymorphism at the gene of ATP-binding cassette transporter 1(ABCA1) was reported to be associated with the profiles. However, no efforts have been made to investigate the changes of lipid profiles after a high-carbohydrate and low-fat diet in different subjects with different genotypes of this polymorphism. This study was to evaluate the effects of ABCA1 R219K polymorphism on serum lipid and apolipoprotein (apo) ratios induced by a high-carbohydrate/low-fat (high-CHO) diet. After a washout diet of 54.1% carbohydrate for 7 days, 56 healthy young subjects (22.89 ± 1.80 years old) were given a high-CHO diet of 70.1% carbohydrate for 6 days. Height, weight, waist circumference, hip circumference, glucose (Glu), triglyceride (TG), total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), apoA-1 and apoB-100 were measured on the 1st, 8th and 14th days of this study. Body mass index (BMI), waist-to-hip ratios (WHR), log(TG/HDL-C), TC/HDL-C, LDL-C/HDL-C and apoA-1/apoB-100 were calculated. ABCA1 R219K was analyzed by a PCR-RFLP method. RESULTS: The results indicate that the male subjects of all the genotypes had higher WHR than their female counterparts on the 1st, 8th and 14th days of this study. The male K carriers had higher log(TG/HDL-C) and TC/HDL-C than the female carriers on the 1st and 14th days, and higher LDL-C/HDL-C on the 14th day. When compared with that on the 8th day, TC/HDL-C was decreased regardless of the genotypes and genders on the 14th day. Log(TG/HDL-C) was increased in the males with the RR genotype and the female K carriers. Lowered BMI, Glu and LDL-C/HDL-C were found in the male K carriers, but only lowered BMI in the female K carriers and only lowered LDL-C/HDL-C in the females with the RR genotype. CONCLUSIONS: These results suggest that ABCA1 R219K polymorphism is associated differently in males and females with elevated log(TG/HDL-C) and decreased LDL-C/HDL-C induced by the high-CHO diet.

Effect of five single nucleotide polymorphisms of ABCG5 and ABCG8 genes on eLipid-lowering response / Efecto de cinco polimorfismos de los genes ABCG5 y ABCG8 sobre la respuesta hipolipemiante a ezetimiba

In this study we evaluated the possible association between five single nucleotide polymorphisms in ABCG5 (rs6720173) and ABCG8 (rs11887534, rs4148211, rs4148217 and rs6544718) genes and ezetimibe response in Chilean hypercholesterolemic subjects. A total of 60 non-related hypercholesterolemic subjects, aged 18 to 65 years old were included in this study. These subjects were treated with ezetimibe (10mg/day) during one month. The ABCG5 and ABCG8 genotypes were assessed by PCR-RFLP. The genotype distribution of the ABCG5/ABCG8 polymorphisms was in Hardy-Weinberg equilibrium. Our results showed that the investigated polymorphisms were not associated with the response to ezetimibe. Nevertheless, the T allele of rs6544718 polymorphism was related to higher baseline levels of LDL-cholesterol (p<0.001). In addition, the G allele for the rs4148211 polymorphism was associated with greater baseline concentrations of triglycerides (P=0.019). This allele was also associated with lower concentrations of HDL-cholesterol (P=0.027), after ezetimibe treatment. Our results suggest that the studied polymorphisms do not affect the therapeutic response to ezetimibe in the evaluated subjects.

En este estudio se evaluó la posible asociación entre cinco polimorfismos de nucleótido único en los genes ABCG5 (rs6720173) y ABCG8 (rs11887534, rs4148211, rs4148217 y rs6544718) y la respuesta a ezetimiba en pacientes hipercolesterolémicos chilenos. Un total de 60 individuos hipercolesterolemicos, no relacionados, con edades entre 18 y 65 años fueron incluidos. Estos sujetos fueron tratados con ezetimiba (10mg/día) durante un mes. Los genotipos de ABCG5 y ABCG8 fueron evaluados por PCR-RFLP. La distribución de genotipos de los polimorfismos de ABCG5/ABCG8 se encontraba en equilibrio de Hardy-Weinberg. Nuestros resultados mostraron que los polimorfismos estudiados no se asociaron con la respuesta a la ezetimiba. Sin embargo, el alelo T del polimorfismo rs6544718 fue relacionado con niveles basales elevados de LDL-colesterol (p <0,001). Además, el alelo G para el polimorfismo rs4148211 se asoció con una mayor concentración basal de triglicéridos (p = 0,019). Este alelo también se asoció con concentraciones más bajas de HDL-colesterol (p = 0,027), después del tratamiento con ezetimiba. Nuestros resultados sugieren que los polimorfismos estudiados no afectan a la respuesta terapéutica a la ezetimiba en los sujetos evaluados.

La respuesta terapéutica a ezetimiba en ratones C57BL/6 es mediada por cambios en la expresión de NPC1L1, ABCG5 y ABCG8 en el enterocito / Therapeutic response to ezetimibe in C57BL/6 mice is mediated by changes in NPC1L1, ABCG5 and ABCG8 expression in the enterocyte

Las proteínas NPC1L1, ABCG5 y ABCG8 participan en la absorción intestinal de colesterol. Ezetimiba inhibe este proceso bloqueando a NPC1L1, sin embargo, su efecto sobre ABCG5 y ABCG8 aún no está claro. Así, el objetivo del presente trabajo fue evaluar en ratones C57BL/6 con hipercolesterolemia inducida por dieta y tratados con ezetimiba, la expresión de NPC1L1, ABCG5 y ABCG8 mediante PCR en tiempo real y Western blot, en 3 grupos de animales: 1, dieta hipercolesterolémica D12336; 2, dieta D12336 más 5 mg/kg/día de ezetimiba; 3, dieta control. El nivel sérico de colesterol total fue significativamente diferente entre los grupos estudiados (control: 1,85 +/- 0,49 mmol/L; dieta D12336: 3,11 +/- 0,73 mmol/L; ezetimiba: 2,11 +/- 0,50 mmol/L, P = 0,001). La expresión génica de NPC1L1 aumentó 5,4 veces en el grupo que recibió la dieta D12336 (P = 0,003). Por otro lado, la expresión génica de ABCG5 y ABCG8 no fue diferente en el grupo con hipercolesterolemia (P = 0,239 y P = 0,201, respectivamente). Después del tratamiento con ezetimiba, la expresión génica de ABCG5 se incrementó 15,6 veces (P = 0.038). No hubo diferencias significativas en la expresión génica de NPC1L1 (P = 0,134) y ABCG8 (P = 0,067). En relación a la expresión proteica, la dieta D12336 incrementó los niveles de expresión de NPC1L1 (P = 0,022) y ABCG5 (P = 0,008); el tratamiento con ezetimiba incrementó los niveles de NPC1L1 (P = 0,048) y redujo los niveles de ABCG5 (P = 0,036) y ABCG8 (P = 0,016). En conclusión, nuestros resultados sugieren que tanto la dieta hipercolesterolémica como el tratamiento con ezetimiba, en un modelo experimental, afectan los niveles de expresión de NPC1L1, ABCG5 y ABCG8, sugiriendo que ABCG5 y ABCG8 están involucrados en la respuesta hipolipemiante a este fármaco. No obstante, el mecanismo mediante el cual se explica esta interacción requiere de un futuro estudio.

Proteins NPC1L1, ABCG5 and ABCG8 are involved in the intestinal absorption of cholesterol. Ezetimibe inhibits this process by blocking NPC1L1, however, its effect on ABCG5 and ABCG8 is not yet clear. Thus, the objective of this study was to evaluate in C57BL / 6 mice with diet-induced hypercholesterolemia treated with ezetimibe, the expression of NPC1L1, ABCG5 and ABCG8 by real time PCR and Western blot, in 3 groups of animals: 1, diet hypercholesterolemic D12336, 2, D12336 diet plus 5 mg/kg/ day of ezetimibe, 3, diet control. The serum level of total cholesterol was significantly different between groups (control: 1.85 +/- 0.49 mmol / L; diet D12336: 3.11 +/- 0.73 mmol / L; ezetimibe: 2.11 +/- 0.50 mmol / L, P = 0.001). NPC1L1 gene expression increased 5.4-fold in the group receiving the diet D12336 (P = 0.003). Furthermore, the gene expression of ABCG5 and ABCG8 was not different in the group with hypercholesterolemia (P = 0.239 and P = 0.201, respectively). After treatment with ezetimibe, ABCG5 gene expression was increased 15.6 times (P = 0.038). No significant differences in gene expression of NPC1L1 (P = 0.134) and ABCG8 (P = 0.067). Regarding protein expression, the D12336 diet increased the levels of expression of NPC1L1 (P = 0.022) and ABCG5 (P = 0.008), treatment with ezetimibe increased the levels of NPC1L1 (P = 0.048) and reduced levels of ABCG5 (P = 0.036) and ABCG8 (P = 0.016). In conclusion, our results suggest that both hypercholesterolemic diet as treatment with ezetimibe, in an experimental model, affect the expression levels of NPC1L1, ABCG5 and ABCG8, suggesting that ABCG5 and ABCG8 are involved in lipid-lowering response to this drug. However, the mechanism by which this interaction is explained requires further study.

Caracterização molecular de transportadores ABC e análise dos níveis intracelulares de antimônio em populações de Leishmania spp. do Novo Mundo sensíveis e resistentes ao antimonial trivalente / Molecular characterization of ABC transporters and analysis of intracellular levels of antimony in populations of Leishmania spp. New World sensitive and resistant trivalent antimony

Transportadores ABC (ATP-binding cassette) abrangem proteínas transmembrana, que utilizam a energia resultante da hidrólise de ATP, para transportar uma variedade de moléculas através de membranas biológicas, incluindo drogas quimioterapêuticas. Alguns membros dessa superfamília ABC estão associados com quimioresistência através da superexpressão de proteínas de resistência a múltiplas drogas (multidrug resistance associated protein – MRP). Uma dessas proteínas é a Pgp (P-glicoproteína), que está relacionada à resistência através da extrusão de compostos tóxicos da célula. O geneMRPA, um transportador da subfamília ABCC, está envolvido na resistência pelo sequestro do conjugado metal-tiol em vesículas próximas da bolsa flagelar da Leishmania. Neste estudo, formas promastigotas de populações sensíveis e resistentes ao antimonial trivalente(SbIII) de quatro espécies de Leishmania, L. (V.) guyanensis, L. (L.) amazonensis, L. (V.) braziliensis e L. (L.) infantum chagasi, foram analisadas quanto: a localização cromossômica, presença de amplificação extracromossomal e análise da amplificação do gene MRPA; níveis de mRNA dos genes MRPA e MRP; expressão da proteína Pgp e determinação do nível intracelular de SbIII...

Inibição do estresse do retículo endoplasmático restaura o conteúdo de ABCA-1 e o efluxo de colesterol em macrófagos tratados com albumina modificada por glicação avançada / Inhibition of endoplasmic reticulum stress restores the ABCA-1 protein level and cholesterol efflux in advanced glycated albumin-treated macrophages

Produtos de glicação avançada (AGE) prejudicam o metabolismo de lipoproteínas e o transporte reverso de colesterol, o que contribui para a aterosclerose no diabete melito (DM). Em particular, a albumina modificada por AGE (albumina-AGE) reduz a remoção de colesterol por diminuir o conteúdo do receptor ABCA-1 em macrófagos. Isto se vincula ao insulto oxidativo e inflamatório, os quais são indutores do estresse do retículo endoplasmático (RE). O objetivo do presente estudo foi avaliar, em macrófagos, os efeitos do tratamento com albumina-AGE sobre o estresse do RE e suas vias adaptativas (UPR), relacionando-os com o prejuízo na expressão do ABCA-1 e efluxo de colesterol celular. Albumina-AGE foi produzida pela incubação de albumina isenta em ácidos graxos com glicolaldeído 10 mM e, albumina controle (albumina-C) com PBS apenas. Albumina foi isolada do soro de pacientes portadores de DM com controle glicêmico inadequado (albumina-DM) ou indivíduos controles (albumina não- DM) por cromatografia para separação rápida de proteínas seguida por purificação alcoólica. Macrófagos de peritônio de camundongos ou macrófagos da linhagem J774 foram tratados com os diferentes tipos de albumina na presença ou ausência de ácido fenil butírico (PBA; chaperona química que alivia o estresse do RE) ou MG-132 (inibidor do sistema proteasomal) por diferentes intervalos de tempo. A expressão de marcadores do estresse do RE, UPR, proteína dissulfeto isomerase (PDI), calreticulina e ubiquitina foi determinada por imunoblot e o conteúdo de ABCA-1, por citometria de fluxo e imunocitoquímica. O efluxo de 14Ccolesterol foi avaliado, utilizando-se apoA-I como aceptora de colesterol. A albumina-AGE induziu aumento tempo-dependente na expressão das chaperonas marcadoras do estresse do RE - Gr78 e Grp94 - e de proteínas da UPR (ATF6 e eIF2-P) em comparação à albumina-C. O conteúdo de ABCA-1 e o efluxo de colesterol foram reduzidos em, respectivamente, 33% e 47% e ambos foram restaurados pelo...

Advanced glycation end products (AGE) disturb lipoprotein metabolism and reverse cholesterol transport, contributing to atherosclerosis in diabetes mellitus (DM). Particularly, advanced glycated albumin (AGE-albumin) reduces cell cholesterol removal by impairing the expression of ABCA-1 in macrophages. This is ascribed to the oxidative and inflammatory stress, conditions that elicit endoplasmic reticulum (ER) stress. In this study it was investigated the effect of AGE-albumin on ER stress and adaptative pathways (UPR) development in macrophages, and its relationship to the reduction in ABCA-1 expression and cholesterol efflux. AGE-albumin was prepared by incubating fatty acid free albumin with 10 mM glycolaldehyde and control albumin (C-albumin) with PBS only. Albumin was isolated from poorly controlled DM patients (DM-albumin) and control individuals (nonDMalbumin) by fast liquid chromatography and purified by alchoolic extraction. Mouse peritoneal macrophages or J774 cells were treated along time with the different types of albumin in the absence or presence of phenyl butiric acic (PBA; a chaperone that aleviates ER stress) or MG132 (a proteasomal inhibitor). The expression of ER stress and UPR markers, protein disulfide isomerase (PDI), calreticulin and ubiquitin was determined by immunoblot and ABCA-1 protein level, by flow cytometry and imunocytochemistry. 14Ccholesterol efflux was evaluated utilizing apo A-I as cholesterol acceptor. AGE-albumin induced a time-dependent increase in the expression of ER stress chaperone markers - Gr78 and Grp94 - and UPR proteins (ATF6 and eIF2-P) in comparison to C-albumin. ABCA-1 content and cholesterol efflux were diminished by, respectively, 33% and 47% and both were recovered by the treatment with PBA. The association between ER stress and ABCA-1 reduction was confirmed by the reduction, induced by tunicanycin (a classical ER stress inductior) in ABCA-1 protein level (61%) and cholesterol efflux (82%). AGE-albumin...

Efeito dos ácidos graxos saturados, poli-insaturados e trans no desenvolvimento de aterosclerose e esteatose hepática em camundongos com ablação gênica do receptor de LDL / Effect of saturated, polyunsaturated and trans fatty acids on the development of atherosclerosis and hepatic steatosis of mice with ablation of the LDL receptor gene

Introdução: A quantidade e o tipo de gordura alimentar exercem importante influência no desenvolvimento de doença cardiovascular (DCV) e podem contribuir para o desenvolvimento de esteatose hepática. Os ácidos graxos saturados e trans são consensualmente apontados como aterogênicos; já os poli-insaturados parecem exercer ação antiaterogênica. Com relação a esteatose hepática, sabe-se que os ácidos graxos saturados estão associados com o seu desenvolvimento; porém, a ação dos ácidos graxos trans na gênese e no desenvolvimento de esteatose hepática não está totalmente elucidada. Neste estudo, avaliou-se o efeito do consumo de dietas enriquecidas com ácidos graxos saturados (SAT), poli-insaturados (POLI) ou trans (TRANS) sobre componentes envolvidos na indução e na progressão da placa aterosclerótica, bem como sobre o desenvolvimento da doença hepática gordurosa não alcoólica. Métodos: Camundongos com ablação gênica para o receptor de LDL (LDLr-KO) foram alimentados com dietas hiperlipídicas (40% do valor calórico total sob a forma de gordura), enriquecidas com ácidos graxos SAT, POLI ou TRANS por 16 semanas e ao final submetidos a: 1) análises plasmáticas: colesterol total (CT), triglicérides (TG), insulina, glicose, aspartato aminotransferase (AST) e alanina aminotransferase (ALT), interleucina-6 (IL-6), fator de necrose tumoral-? (TNF-alfa) e perfil de lipoproteínas; 2) determinação da lesão aterosclerótica: área de lesão (Oil Red-O), conteúdo de ATP-binding cassette transporter A1 (ABCA1) e infiltrado de macrófagos (imuno-histoquímica), colocalização de ABCA1 e macrófagos (microscopia confocal) e conteúdo de colágeno (Picrosirius-Red) na raiz aórtica; 3) conteúdo de CT, colesterol éster (CE) e colesterol livre (CL) na aorta total; 4) macrófagos peritoneais foram tratados com lipopolissacarídeo...

Introduction: The amount and type of dietary fat play important roles on the development of cardiovascular disease (CVD) and on the development of hepatic steatosis. Saturated (SAT) and trans (TRANS) fatty acids are known as pro-atherogenic, while the polyunsaturated (POLY) fats seem to exert an antiatherogenic action. Regarding hepatic steatosis, it is known that SAT are associated with its development, however, the role of TRANS in the genesis and development of hepatic steatosis is not fully undestood. This study evaluated the effect of the intake of diets enriched with SAT, POLY or TRANS on the parameters involved in the progression of the atherosclerotic plaque and also on the development of the nonalcoholic fatty liver disease (NAFLD). Methods: LDL receptor knock-out (LDLR-KO) male mice were fed for 16 weeks a high fat diet (40% of calories as fat) enriched with SAT, POLY or TRANS, for 16 weeks. The following parameters were mesured: 1) plasma: total cholesterol (TC), triglyceride (TG), insulin, glucose, aspartate aminotransferase (AST) and alanine amino transferase (ALT), interleukin-6 (IL-6), tumor necrosis factor- ? (TNF-?) and lipoprotein profile; 2) atherosclerotic lesion - lesion area (Oil Red-O), ATP-binding cassette transporter A1 (ABCA1) content and macrophage infiltration (immunohistochemistry), co-localization of ABCA1 and macrophages (confocal microscopy) and collagen content (Picrosirius-Red); 3) TC, cholesteryl ester (CE) and free cholesterol (FC) content of the total aorta; 4) interleukin-6 and 10 (IL-6 and IL-10) and TNF-alfa in the culture medium of peritoneal macrophages after treatment with lipopolysaccharide (LPS); 5) liver: degree of fat liver disease, concentration of TC and TG and mRNA expression (RT-qPCR) of PPAR-gama, PPAR-gama, SREBP-1c, MTP, ABCA1 and CPT-1; 6)...

Caracterização molecular de transportadores ABC e análise dos níveis intracelulares de antimônio em populações de Leishmania spp. do Novo Mundo sensíveis e resistentes ao antimonial trivalente

Transportadores ABC (ATP-binding cassette) abrangem proteínas transmembrana, que utilizam a energia resultante da hidrólise de ATP, para transportar uma variedade de moléculas através de membranas biológicas, incluindo drogas quimioterapêuticas. Alguns membros dessa superfamília ABC estão associados com quimioresistência através da superexpressão de proteínas de resistência a múltiplas drogas (multidrug resistance associated protein – MRP). Uma dessas proteínas é a Pgp (P-glicoproteína), que está relacionada à resistência através da extrusão de compostos tóxicos da célula. O geneMRPA, um transportador da subfamília ABCC, está envolvido na resistência pelo sequestro do conjugado metal-tiol em vesículas próximas da bolsa flagelar da Leishmania. Neste estudo, formas promastigotas de populações sensíveis e resistentes ao antimonial trivalente(SbIII) de quatro espécies de Leishmania, L. (V.) guyanensis, L. (L.) amazonensis, L. (V.) braziliensis e L. (L.) infantum chagasi, foram analisadas quanto: a localização cromossômica, presença de amplificação extracromossomal e análise da amplificação do gene MRPA; níveis de mRNA dos genes MRPA e MRP; expressão da proteína Pgp e determinação do nível intracelular de SbIII

Ensaios de PFGE indicaram a associação de amplificação cromossomal e extracromossomal do gene MRPA com o fenótipo de resistência à droga nas espécies de Leishmania estudadas. Os resultados obtidos através de lise alcalina dos parasitos mostraram a presença de amplificação extracromossomal apenas na amostra resistente de L. (V.) braziliensis. Análises de Southern blot com as endonucleases BamHI e HindIII indicaram a presença de polimorfismos na sequência do gene MRPA em algumas amostras de Leishmania analisadas. Adicionalmente, foi observada amplificação desse gene nas populações de Leishmania resistentes ao SbIII. Ensaios de PCR quantitativo em tempo real mostraram aumento dos níveis de mRNA do gene MRPA nas populações resistentes de L. (L.) amazonensis e L. (V.) braziliensis, comparado com seus respectivos pares sensíveis. Os níveis de mRNA do gene MRP estão aumentados em todas as populações de Leishmania resistentes ao SbIII analisadas neste estudo. Os resultados de Western blot revelaram que a proteína Pgp está mais expressa nas populações resistentes de L. (V.) guyanensis e L. (L.) amazonensis. Os dados obtidosde quantificação dos níveis intracellulares de SbIII por espectrometria de absorção atômicaem forno de grafite mostraram uma redução no acúmulo de SbIII, nas populaçõesresistentes de L. (V.) guyanensis, L. (L.) amazonensis e L. (V.) braziliensis, quando comparadas às respectivas populações sensíveis. Nossos resultados indicam que os mecanismos de resistência ao antimônio são diferentes entre as espécies de Leishmania analisadas

Evaluación del transporte de glucosa, fármacos y del potencial de membrana como métodos pronósticos de quimioterapia en Leishmania spp / Evaluation of glucose transport, drugs and membrane potential as prognostic methods of chemotherapy in Leishmania spp

El fracaso terapéutico en leishmaniasis a menudo esta asociado a resistencia a los medicamentos por parte de los parásitos. Hasta ahora no se ha evaluado sistemáticamente si este fenotipo compromete u optimiza el metabolismo o la efectividad en leishmania, es decir, su competencia y adaptabilidad. Durante su ciclo de vida los parásitos deben ajustarse a condiciones de vida extremas, lo cual no es gratuito. Al presentarse conflictos que comprometen propiedades de leishmania esenciales para su supervivencia, surge un costo de adaptación. Sin embargo, tales compensaciones son el precio a pagar que garantizan la co-evolucion del binomio hospedero-parásito y el mantenimiento de la diversidad genética de leishmania. Comprender ese costo es imprescindible a fin de diseñar medidas de prognosis y control exitosas. Adicionalmente, el método vigente y confiable para evaluar resistencia en leishmania es el método in vitro macrofago-amastigote, el cual es oneroso y laborioso. Como parte de un proyecto sobre quimo-resistencia en Leismania, planteamos evaluar posibles parámetros bioquímicos que pudieran servir como marcadores celulares a ser usados para identificar parásitos con fenotipo quimioresistentes en aislados de pacientes y compararlos con cepas de referencia. Los resultados sugieren que algunos aislados:a) tienen incrementada la expresión transportadores ABC, b) utilizan glucosa de forma diferencial, c) tienen un potencial de membrana menos polarizado y d) expresan diferente sensibilidad a inhibidores clásicos de la función mitocondrial. En conjunto, los datos indican que los aislados estudiados expresan los mismos cambios fisiológicos ya descritos en parásitos de referencia quimioresistentes. Es decir, que los cambios explorados podrían constituir un patrón general asociado a este fenómeno leishmania, lo cual los valida como marcadores celulares de resistencia. En conclusion, se propone un nuevo enfoque al problema del tratamiento de la enfermedad ya que, además de las estrategias clásicas, se añadirían herramientas de pronostico del éxito de la quimioterapia.

Glioblastoma multiforme y estudio de la resistencia a la quimioterapia mediada por transportadores ABC / Study of resistance to chemotherapy mediated by ABC transporters in biopsies of glioblastoma multiforme

Background: Mortality rate is dramatically high in high grade brain tumors. The presence of multiple drug resistance transporters in glioblastoma multiforme, has contributed largely to the poor effcacy of targeted therapy against cancer in the central nervous system. Aim: To analyze the percentage of survival and mortality of patients with glioblastoma multiforme in a cohort of patients in Chile and to co-rrelate the chemo-resistance of these cells with the expression level of multiple drug resistance transporters. Materials and Methods: Eighteen biopsies of glioblastoma multiforme were obtained from patients at the Institute of Neurosurgery Dr. Asenjo (INCA). The tumor cells were obtained from primary cultures and the expression and activity of multiple drug resistance transporters was assessed by RT-PCR and immunohistochemistry. Population-based study was performed using the databases of the Department of Neurosurgery of INCA. Results: The number of patients with glioblastoma multiforme increased between 2007 and 2009, from 3.5 percent to 7.9 percent of total brain tumors. Mortality of these tumors is 90 percent at three years. A high expression and activity of the multiple drugs resistance associated protein 1 (Mrp1) transporter was observed in primary cultures of biopsies. Conclusions: We propose that Mrp1 activity is responsible for the chemo-resistance of the glioblastoma multiforme and inhibition of this transporter could represent a plausible strategy for the treatment.

Glicação avançada em macrófagos diminui o conteúdo dos receptores de HDL - ABCA-1 e ABCG-1- e induz acúmulo intracelular de 7 -cetocolesterol / Advanced Glycation in macrophages decreases the content of the HDL receptor ABCA-1 and ABCG-1 - and induces intracellular accumulation of 7-ketocholesterol

Produtos de glicação avançada (AGE) alteram o metabolismo de lípides e, em especial, o efluxo de colesterol de macrófagos, por meio da redução dos receptores ABCA-1 e ABCG-1. Isto prejudica o transporte reverso de colesterol, sistema que favorece o fluxo de colesterol de macrófagos arteriais ao fígado, permitindo sua excreção na bile e eliminação fecal. Óxidos de colesterol modulam favoravelmente a homeostase lipídica em macrófagos e favorecem o transporte reverso de colesterol, embora o acúmulo de 7-cetocolesterol, 7-hidroxicolesterol e 7-hidroxicolesterol associe-se à aterogênese e morte celular. Neste estudo, avaliou-se o efeito do tratamento com glicolaldeído (GAD; oxoaldeído que induz rápida geração intracelular de AGE), em macrófagos sobrecarregados com LDL oxidada e incubados com HDL ou HDL e indutor de LXR (T0901317) sobre: 1) a distribuição seletiva de óxidos de colesterol e o conteúdo total de esteróis intracelulares e 2) o conteúdo de ABCA-1 e ABCG-1. Colesterol total e os diversos subtipos de óxidos de colesterol foram determinados por cromatografia a gás acoplada à espectrômetro de massa. O conteúdo dos receptores de HDL (ABCA-1 e ABCG-1) foi avaliado por imunoblot. Em macrófagos controles (C), a adição de HDL ou HDL + T0901317 promoveu redução no conteúdo de esteróis totais (colesterol + óxidos de colesterol), colesterol e 7-cetocolesterol. No entanto, isto não foi observado em macrófagos GAD. Nas diversas condições experimentais, não houve diferença no conteúdo intracelular dos outros subtipos de óxidos de colesterol, em células C e GAD. Macrófagos GAD apresentaram menor conteúdo de ABCA-1 (45%), quando comparados aos macrófagos C, mesmo após adição de HDL ou HDL + T0901317. O conteúdo de ABCG-1 foi 36,6% menor em macrófagos GAD, na presença de HDL, em comparação às células C. Em conclusão, em macrófagos sobrecarregados com LDL oxidada, o tratamento com glicolaldeído diminui a exportação celular de colesterol e 7-cetocolesterol...

Advanced glycation end products (AGE) alter lipid metabolism and reduce the macrophage expression of ABCA-1 and ABCG-1 which impairs the reverse cholesterol transport, a system that drives cholesterol from arterial wall macrophages to the liver, allowing its excretion into the bile and feces. Oxysterols favors lipid homeostasis in macrophages and drive the reverse cholesterol transport, although the accumulation of 7-ketocholesterol, 7- hydroxycholesterol and 7- hydroxycholesterol is related to atherogenesis and cell death. We evaluated the effect of glycolaldehyde treatment (GAD; oxoaldehyde that induces a fast formation of intracellular AGE) in macrophages overloaded with oxidized LDL and incubated with HDL alone or HDL plus LXR agonist (T0901317) in: 1) the intracellular content of oxysterols and total sterols and 2) the contents of ABCA-1 and ABCG-1. Total cholesterol and oxysterol subspecies were determined by gas chromatography/mass spectrometry and HDL receptors content by immunoblot. In control macrophages (C), incubation with HDL or HDL + T0901317 reduced the intracellular content of total sterols (total cholesterol + oxysterols), cholesterol and 7-ketocholesterol, which was not observed in GAD macrophages. In all experimental conditions no changes were found in the intracellular content of other oxysterol subspecies comparing C and GAD macrophages. GAD macrophages presented a 45% reduction in ABCA-1 protein level as compared to C cells, even after the addition of HDL or HDL + T0901317. The content of ABCG-1 was 36.6% reduced in GAD macrophages in the presence of HDL as compared to C macrophages. In conclusion, in macrophages overloaded with oxidized LDL, glycolaldehyde treatment reduces the HDL-mediated cholesterol and 7-ketocholesterol efflux which is ascribed to the reduction in ABCA-1 and ABCG-1 protein level. This may contribute to atherosclerosis in diabetes mellitus...

Efeito de hipolipemiantes sobre a expressão de genes envolvidos no transporte reverso do colesterol / Statin effects on expression of genes involved in reverse cholesterol transport

A eficácia das estatinas em reduzir o risco de eventos coronarianos não é completamente explicada por seus efeitos em diminuir colesterol de lipoproteína de baixa densidade (LDL-C). Um dos seus efeitos adicionais pode ser decorrente da modificação na concentração de lipoproteína de alta densidade (HDL), reconhecida como ateroprotetora, principalmente por seu papel no transporte reverso do colesterol (TRC). Os transportadores de membrana do tipo ATP-binding cassette, ABCA1 e ABCG1, e o scavenger receptor BI (SRBI) são proteínas importantes envolvidas no TRC e seus genes são regulados por vários fatores de transcrição, entre eles os liver-x-receptors (LXRs). Com a finalidade de avaliarmos os efeitos dos hipolipemiantes sobre expressão dos transportadores ABC e do receptor SRBI, a expressão de RNAm do ABCA1, ABCG1, SCARB1, NR1H3 (LXRα) e NR1H2 (LRXß) foi avaliada por PCR em tempo real em células das linhagens HepG2 (origem hepática) e Caco-2 (origem intestinal) tratadas com atorvastatina ou sinvastatina (10 µM) e/ou ezetimiba (até 5 µM) por até 24 horas. Além disso, a expressão desses genes também foi avaliada em células mononucleares do sangue periférico (CMSP) de 50 pacientes normolipidêmicos (NL) e 71 hipercolesterolêmicos (HC) tratados com atorvastatina (10mg/dia/4semanas, n=48) ou sinvastatina e/ou ezetimiba (10mg/dia/4 ou 8 semanas, n=23). A possível associação entre os polimorfismos ABCA1 C-14T e R219K e a expressão de RNAm em CMSP também foi avaliada por PCR-RFLP. O SCARB1 foi o gene mais expresso nas células HepG2 e Caco-2, seguido por NR1H2, NR1H3, ABCG1 e ABCA1 em HepG2 ou por ABCA1 e ABCG1 em Caco-2. O tratamento com estatinas (1 ou 10 µM) ou ezetimiba (5 µM), por 12 ou 24 horas, aumentou a expressão de RNAm do ABCG1, mas não de ABCA1 e SCARB1, em células HepG2. Ainda nesta linhagem, o aumento na transcrição dos genes NR1H2 e NR1H3 foi observado somente com a maior concentração de atorvastatina (10 µM) e, ao contrário, o tratamento com ezetimiba causou redução na transcrição de NR1H2, sem alteração de NR1H3. Em células Caco-2, o tratamento com atorvastatina ou sinvastatina por 12 ou 24 horas reduziu a quantidade do transcrito ABCA1 e não alterou a expressão do SCARB1 e do ABCG1, embora, para este último, tenha havido uma tendência à diminuição da expressão após tratamento com sinvastatina (p=0,07). Após tratamento com ezetimiba isolada (até 5 µM) nenhuma alteração de expressão de RNAm foi observada em células Caco-2; no entanto, após 24 horas de tratamento com sinvastatina e ezetimiba, foi reduzida a taxa de transcrição de ABCA1 e ABCG1, mas não de SCARB1. Ao contrário das linhagens celulares, em CMSP os genes NR1H2 e ABCG1 foram os mais expressos, seguidos pelos genes SCARB1 e ABCA1 e, finalmente, pelo NR1H3. Indivíduos HC tiveram maior expressão basal de NR1H2 e NR1H3, mas não de outros genes, quando comparados aos NL (p<0,05). Além disso, nos indivíduos HC, a expressão basal de ABCA1 foi maior em portadores do alelo -14T do polimorfismo ABCA1 -14C>T quando comparados aos portadores do genótipo -14CC (p=0,034). O tratamento com estatinas, com ezetimiba ou com a terapia combinada diminuiu a transcrição de ABCA1 e ABCG1. Para o SCARB1, NR1H2 e NR1H3, nenhuma alteração de expressão de RNAm em CMSP foi detectada após os tratamentos in vivo. Após todas as fases de tratamento, ABCA1 e ABCG1 e também NR1H2 e NR1H3 foram significativamente correlacionados entre si, mas nenhuma correlação com perfil lipídico sérico foi relevante. Coletivamente, esses resultados dão indícios de que os hipolipemiantes analisados (estatinas e ezetimiba) têm um importante papel na regulação da expressão de genes envolvidos no transporte reverso do colesterol e sugerem a existência de regulação tecido-específica para os dois transportadores ABC. Além disso, o efeito das estatinas ou da ezetimiba sobre a expressão do ABCA1, do ABCG1 ou do SCARB1 não sofreu influencia de alterações diretas da transcrição dos LXRs

The efficacy of statins in reducing the risk of coronary events is not completely explained by their effects in decreasing cholesterol low-density lipoprotein (LDL-C). One of their additional effects may result from the change in concentration of high-density lipoprotein (HDL), recognized as atheroprotective, mainly for the role in reverse cholesterol transport (RCT). The membrane transporters, as ATP-binding cassette, ABCA1 and ABCG1, and scavenger receptor BI (SRBI) are important proteins involved in the RCT and their genes are regulated by various transcription factors, including the liver-X-receptors (LXRs) . In order to evaluate the effects of lipid lowering on expression of ABC transporters and SRBI receptor, the mRNA expression of ABCA1, ABCG1, SCARB1, NR1H3 (LXRα) and NR1H2 (LRXß) was assessed by real time PCR in HepG2 (hepatic origin) and Caco-2 (intestinal origin) cells treated with atorvastatin or simvastatin (10 µM) and/or ezetimibe (up to 5 µM) for 24 hours. Furthermore, the expression of these genes was evaluated in peripheral blood mononuclear cells (PBMC) of 50 normolipidemic (NL) and 71 hypercholesterolemic (HC) patients treated with atorvastatin (10mg/d/4 weeks, n = 48) or simvastatin and/or ezetimibe (10mg/d/4 or 8 weeks, n = 23). The possible association between ABCA1 C-14T and R219K polymorphisms and mRNA expression in PBMC was also evaluated by PCR-RFLP. SCARB1 was the most expressed in HepG2 and Caco-2 cells, followed by NR1H2, NR1H3, ABCG1 and ABCA1 in HepG2 or by ABCG1 and ABCA1 in Caco-2. The treatment with statins (1 or 10 µM) or ezetimibe (5 µM) for 12 or 24 hours, increased mRNA expression of ABCG1 but not ABCA1 and SCARB1 in HepG2 cells. Moreover, in HepG2 cells, atorvastatin also upregulated NR1H2 and NR1H3 only at 10.0 µM, meanwhile ezetimibe downregulated NR1H2 but did not change NR1H3 expression. In Caco-2 cells, atorvastatin or simvastatin treatment for 12 or 24 hours reduced the amount of ABCA1 transcript and did not alter the ABCG1 and SCARB1 expressions, despite the tendency to decrease ABCG1 mRNA expression after simvastatin treatment (p = 0.07). After treatment with ezetimibe alone (up to 5 µM) no change in mRNA expression was observed in Caco-2 cells; however, after 24 hours- simvastatin and ezetimibe treatments decreased the transcription of ABCA1 and ABCG1, but not of SCARB1. Unlike cell lines, in PBMC, NR1H2 and ABCG1 were the most expressed, followed by SCARB1 and ABCA1 and finally by the NR1H3. HC patients showed higher NR1H2 and NR1H3 basal expressions, but not of other genes, compared to NL (p <0.05). Moreover, in HC individuals, the ABCA1 basal expression was higher in individuals carrying -14T allele of -14C> T polymorphism when compared with -14CC carriers (p = 0.034). Treatment with statins, ezetimibe, or combined therapy downregulated ABCA1 and ABCG1 expression. For SCARB1, NR1H2 and NR1H3, no change in mRNA expression in PBMC was detected after treatments. After all phases of treatment, ABCA1 and ABCG1 as well as NR1H2 and NR1H3 were significantly correlated, but no correlation with serum lipid profile was relevant. Collectively, these results provide evidences that the lipid lowering (statins and ezetimibe) have an important role in mRNA expression regulation of genes involved in reverse cholesterol transport and suggest the existence of tissue-specific regulation for the ABC transporters. Furthermore, the effect of statins or ezetimibe on ABCA1, ABCG1 or SCARB1 expression was not directly influenced by changes of LXR transcription

Efeito de hipolipemiantes sobre a expressão de genes envolvidos no transporte reverso do colesterol / Statin effects on expression of genes involved in reverse cholesterol transport

A eficácia das estatinas em reduzir o risco de eventos coronarianos não é completamente explicada por seus efeitos em diminuir colesterol de lipoproteína de baixa densidade (LDL-C). Um dos seus efeitos adicionais pode ser decorrente da modificação na concentração de lipoproteína de alta densidade (HDL), reconhecida como ateroprotetora, principalmente por seu papel no transporte reverso do colesterol (TRC). Os transportadores de membrana do tipo ATP-binding cassette, ABCA1 e ABCG1, e o scavenger receptor BI (SRBI) são proteínas importantes envolvidas no TRC e seus genes são regulados por vários fatores de transcrição, entre eles os liver-x-receptors (LXRs). Com a finalidade de avaliarmos os efeitos dos hipolipemiantes sobre expressão dos transportadores ABC e do receptor SRBI, a expressão de RNAm do ABCA1, ABCG1, SCARB1, NR1H3 (LXRα) e NR1H2 (LRXβ) foi avaliada por PCR em tempo real em células das linhagens HepG2 (origem hepática) e Caco-2 (origem intestinal) tratadas com atorvastatina ou sinvastatina (10 µM) e/ou ezetimiba (até 5 µM) por até 24 horas. Além disso, a expressão desses genes também foi avaliada em células mononucleares do sangue periférico (CMSP) de 50 pacientes normolipidêmicos (NL) e 71 hipercolesterolêmicos (HC) tratados com atorvastatina (10mg/dia/4semanas, n=48) ou sinvastatina e/ou ezetimiba (10mg/dia/4 ou 8 semanas, n=23). A possível associação entre os polimorfismos ABCA1 C-14T e R219K e a expressão de RNAm em CMSP também foi avaliada por PCR-RFLP. O SCARB1 foi o gene mais expresso nas células HepG2 e Caco-2, seguido por NR1H2, NR1H3, ABCG1 e ABCA1 em HepG2 ou por ABCA1 e ABCG1 em Caco-2. O tratamento com estatinas (1 ou 10 µM) ou ezetimiba (5 µM), por 12 ou 24 horas, aumentou a expressão de RNAm do ABCG1, mas não de ABCA1 e SCARB1, em células HepG2. Ainda nesta linhagem, o aumento na transcrição dos genes NR1H2 e NR1H3 foi observado somente com a maior concentração de atorvastatina (10 µM) e, ao contrário, o tratamento com ezetimiba...

The efficacy of statins in reducing the risk of coronary events is not completely explained by their effects in decreasing cholesterol low-density lipoprotein (LDL-C). One of their additional effects may result from the change in concentration of high-density lipoprotein (HDL), recognized as atheroprotective, mainly for the role in reverse cholesterol transport (RCT). The membrane transporters, as ATP-binding cassette, ABCA1 and ABCG1, and scavenger receptor BI (SRBI) are important proteins involved in the RCT and their genes are regulated by various transcription factors, including the liver-X-receptors (LXRs) . In order to evaluate the effects of lipid lowering on expression of ABC transporters and SRBI receptor, the mRNA expression of ABCA1, ABCG1, SCARB1, NR1H3 (LXRα) and NR1H2 (LRXβ) was assessed by real time PCR in HepG2 (hepatic origin) and Caco-2 (intestinal origin) cells treated with atorvastatin or simvastatin (10 µM) and/or ezetimibe (up to 5 µM) for 24 hours. Furthermore, the expression of these genes was evaluated in peripheral blood mononuclear cells (PBMC) of 50 normolipidemic (NL) and 71 hypercholesterolemic (HC) patients treated with atorvastatin (10mg/d/4 weeks, n = 48) or simvastatin and/or ezetimibe (10mg/d/4 or 8 weeks, n = 23). The possible association between ABCA1 C-14T and R219K polymorphisms and mRNA expression in PBMC was also evaluated by PCR-RFLP. SCARB1 was the most expressed in HepG2 and Caco-2 cells, followed by NR1H2, NR1H3, ABCG1 and ABCA1 in HepG2 or by ABCG1 and ABCA1 in Caco-2. The treatment with statins (1 or 10 µM) or ezetimibe (5 µM) for 12 or 24 hours, increased mRNA expression of ABCG1 but not ABCA1 and SCARB1 in HepG2 cells. Moreover, in HepG2 cells, atorvastatin also upregulated NR1H2 and NR1H3 only at 10.0 µM, meanwhile ezetimibe downregulated NR1H2 but did not change NR1H3 expression. In Caco-2 cells, atorvastatin or simvastatin treatment for 12 or 24 hours reduced the amount of ABCA1 transcript and did not ...

Phenotypic variability in a family with x-linked adrenoleukodystrophy caused by the p.Trp132Ter mutation / Variabilidade fenotípica em uma família com adrenoleucodistrofia ligada ao X causada pela mutação p.Trp132Ter

X-linked adrenoleukodystrophy (X-ALD) is an inherited disease with clinical heterogeneity varying from presymptomatic individuals to rapidly progressive cerebral ALD forms. This disease is characterized by increased concentration of very long chain fatty acids (VLCFAs) in plasma and in adrenal, testicular and nervous tissues. Affected individuals can be classified in different clinical settings, according to phenotypic expression and age at onset of initial symptoms. Molecular defects in X-ALD individuals usually result from ABCD1 gene mutations. In the present report we describe clinical data and the ABCD1 gene study in two boys affected with the childhood cerebral form that presented with different symptomatic manifestations at diagnosis. In addition, their maternal grandfather had been diagnosed with Addison's disease indicating phenotypic variation for X-ALD within this family. The mutation p.Trp132Ter was identified in both male patients; additionally, three females, out of eleven family members, were found to be heterozygous after screening for this mutation. In the present report, the molecular analysis was especially important since one of the heterozygous females was in first stages of pregnancy. Therefore, depending on the fetus outcome, if male and p.Trp132Ter carrier, storage of the umbilical cord blood should be recommended as hematopoietic stem cell transplantation could be considered as an option for treatment in the future.

A adrenoleucodistrofia é uma doença genética com padrão de herança ligado ao X (X-ALD) que apresenta heterogeneidade clínica e varia desde a forma infantil cerebral severa até casos de indivíduos pré-sintomáticos. Essa doença é caracterizada pelo acúmulo de ácidos graxos de cadeia muito longa (VLCFA) no plasma, nas adrenais, nos testículos e no sistema nervoso. Indivíduos afetados podem apresentar diferentes formas clínicas, as quais são classificadas de acordo com a expressão fenotípica e a idade de aparecimento dos sintomas iniciais. Alterações moleculares em indivíduos com X-ALD são geralmente mutações no gene ABCD1. No presente trabalho, descrevemos os dados clínicos e a investigação molecular do gene ABCD1 em uma família com duas crianças do sexo masculino afetadas com a forma infantil cerebral, que apresentaram diferenças nas primeiras manifestações sintomáticas para o diagnóstico. Além disso, houve referência ao avô materno diagnosticado com doença de Addison's, indicando a variabilidade fenotípica da X-ALD nessa família. A análise molecular indicou a mutação p.Trp132Ter nos dois pacientes masculinos, e três indivíduos do sexo feminino, entre os onze estudados, mostraram-se heterozigotos para mutação. O conhecimento molecular descrito no presente relato adquiriu maior importância uma vez que uma das portadoras da mutação apresentou-se nos primeiros estágios de gestação. Assim, poderá ser oferecida a possibilidade de armazenamento de sangue de cordão umbilical para que se possa considerar, no futuro, o transplante de células-tronco hematopoiéticas como forma de tratamento, caso a criança seja do sexo masculino e afetada.