No description available.

With the goal of creating faster and more efficient methods of generating unique Ac/Ds insertional mutants in a population of Fragaria vesca, various methods of seed germination, kanamycin screening, and the effects of varying nitrogen fertilization on diploid strawberry have been examined. Seed germination was improved to 42% in B5 liquid medium compared to _ on MS solid medium. Kanamycin screening during germination was most effective in liquid B5 medium as well. A readily discernable phonotypic difference between sensitive (necrotic radical) and resistant (branched roots) seedlings was observed in the B5 liquid medium and the frequency of escapes was reduced from __ on solid MS to __ in liquid B5. Although there were few phenotypic differences due to nitrogen application over the tested treatments (25-300 ppm) runner initiation was suppressed and chlorophyll was increased in the high (300 ppm) nitrogen treatment. There was limited evidence to suggest an increased rate of transposition in the high (300 ppm nitrogen) treatment level compared to those plants receiving lower levels of nitrogen. The selection efficiency and greater germination of the B5 liquid medium over MS medium would be expected to reduce the cost of screening thousands of seedlings because of the need for fewer disposables and medium transfers during the 5 week germination process. The use of B5 liquid medium, as well as treating plants with high levels of nitrogen (300 ppm), may be facilitate high throughput production of transposon tagged mutants in a population of F. vesca. / Master of Science

Introdução: Os fitoesteróis (FE) são reconhecidos por reduzirem a concentração plasmática de LDL-colesterol, sendo importantes coadjuvantes no tratamento da hipercolesterolemia moderada. Entretanto, estudos publicados recentemente demonstram resultados conflitantes em relação à eficiência dos FE na prevenção da aterosclerose. Além disso, algumas investigações evidenciaram que o aumento da concentração plasmática de FE está positivamente relacionado ao risco de desenvolvimento de aterosclerose. Com a finalidade de elucidar a sua ação sobre esses parâmetros, o objetivo deste estudo foi avaliar os efeitos da suplementação de FE no desenvolvimento da aterosclerose em camundongos com ablação gênica para o receptor de LDL (LDLr-KO). Métodos: Os animais foram alimentados durante 16 semanas, com dieta rica em gordura (40% do valor calórico total da dieta), suplementada (grupo FE; 2%, n=10) ou não (Controle; n=10) com FE. Foram avaliadas as concentrações plasmáticas e hepáticas de colesterol, triglicérides, FE (beta-sitosterol, campesterol e latosterol). Na aorta dos animais, determinaram-se as concentrações de colesterol total, colesterol livre e éster e FE, além do infiltrado de macrófagos e infiltrado de lípides. Nos macrófagos do peritôneo dos animais, os quais assemelham-se aos presentes na artéria, avaliou-se a expressão de RNA mensageiro dos genes envolvidos no efluxo e influxo de colesterol (ABCA1, ABCG1, LOX1 e CD36). Também determinou-se as concentrações de FE no intestino e baço dos animais. Resultados: Conforme esperado, o consumo de FE induziu elevação plasmática dos principais FE, campesterol e de beta-sitosterol, reduzindo a concentração de colesterol no plasma. Houve aumento nas concentrações hepáticas de triglicérides e FE, entretanto, não foram observadas diferenças entre os grupos nas expressões de RNA mensageiro de genes lipolíticos (CPT, PPAR alfa) e lipogênicos (SREBP1-c, MTP, LXR e PPAR gamma) no fígado. Não houve, também, alteração no SREBP2, gene relacionado à síntese de colesterol. O conteúdo de colesterol total na artéria foi menor nos animais do grupo FE, não diferindo entre as formas livre e éster. As concentrações de FE na artéria foram iguais entre os grupos. A área de lesão no grupo FE foi menor em relação ao grupo-controle. A suplementação com FE induziu redução na expressão de RNA mensageiro de ABCG1, não interferindo na expressão dos outros genes estudados na artéria. Conclusão: Os achados deste estudo demonstram que a elevação de FE no plasma não induziu o seu acúmulo na parede da artéria e preveniu o desenvolvimento da aterosclerose / Introduction: The plasma cholesterol-reducing effect of hytosterols (PS) is well recognized and they are considered important adjuncts in the treatment of moderate hypercholesterolemia. However, recent studies have shown conflicting results regarding the efficiency of PS in the prevention of atherosclerosis. In addition, some studies showed that the increase in plasma PS concentration is positively correlated to the risk of atherosclerosis. In order to elucidate its action on these parameters, the objective of this study was to evaluate the effects of PS supplementation in the development of atherosclerosis in LDL receptor knock-out mice (LDLr -KO). Methods: The animals were fed during 16 weeks with high fat diet (40 % of calories as fat), supplemented (PS group, 2%, n = 10) or not (Control, n = 10) with PS. Plasma and liver concentrations of cholesterol, triglycerides, PS (beta - sitosterol, campesterol and lathosterol) were evaluated. In the aorta of the animals, the concentrations of total cholesterol, free cholesterol, cholesterol ester and PS, besides macrophage and lipids infiltration were determined. The mRNA expression of genes involved in cholesterol efflux and influx (ABCA1, ABCG1, LOX1 and CD36) were evaluated, in peritoneum macrophage, which resemble those present in the artery. It was also determined the intestine and spleen PS concentrations from the animals of both groups. Results: As expected, PS supplementation induced increasing plasma concentration of the main PS, campesterol and beta -sitosterol and reducing cholesterol plasma concentration. It was observed an increase so intestine and spleen PS concentrations. There was an increase in hepatic triglyceride concentrations and PS, however, no differences were observed between the groups of hepatic mRNA expression of lipolytic (CPT, PPARalfa) and lipogenic genes (SREBP1c, MTP, CPT, LXR, and PPAR gamma). There was no difference on SREBP2, gene related to cholesterol synthesis. The content of total cholesterol in the artery was lower in PS group animals however did not differ between the free and ester forms. Artery PS concentrations did not differ between groups. The lesion area in the PS group was lower than in the control group. PS supplementation induced reduction in mRNA expression of ABCG1, not affecting the expression of other genes studied in artery. Conclusion: The findings of this study demonstrate that the elevation of plasma PS concentration did not induce its accumulation in the arterial wall and prevented the development of atherosclerosis

A doença de Chagas é uma doença causada pelo protozoário parasita Trypanosoma cruzi, que afeta cerca de 10 milhões de pessoas, principalmente nas Américas. O T. cruzi utiliza aminoácidos como importante fonte de energia e em vários processos biológicos como diferenciação, resistência a condições de estresse e invasão de células hospedeiras. A serina está envolvida em muitas vias biosintéticas. Uma das funções relevantes da serina é a formação de compostos C1 para a biossíntese de nucleotídeos. O uso de serina para esse fim é iniciado pela Serina Hidroximetiltransferase, cuja atividade foi detectada em T. cruzi, mas seu papel na biologia do parasita permanece pouco explorado. Neste trabalho, identificamos um gene que codifica uma Serina Hidroximetiltransferase putativa com dupla localização (citoplasmática e mitocondrial). Por recombinação homóloga, obtemos parasitas knockouts heterozigotos nos quais um alelo de SHMT foi substituído pelo gene da neomicina fosfotransferase. Os parasitas knockouts não mostraram diferenças na taxa de crescimento das formas epimastigotas ou na metaciclogênese in vitro. Porém, os parasitas knockouts mostraram uma diminuição significativa tanto no índice de infecção como no número de tripomastigotas liberados de células CHO-K1 infectadas com formas metacíclicas knockout. / Chagas disease is a disorder caused by the protozoa parasite Trypanosoma cruzi, which affects about 10 million people, mainly in the Americas. T. cruzi uses amino acids as an important energy source and in several biological processes such as differentiation, resistance to stress conditions and in the host-cell invasion. Serine is involved in many biosynthetic pathways. One of the relevant functions of serine is the formation of C1 compounds for the biosynthesis of nucleotides. The use of serine for that purpose is initiated by Serine Hydroxymethyltransferase, whose activity was detected in T. cruzi but its role in the biology of parasite remains poorly explored. In this work we identified a putative gene encoding a SHMT with dual localization, cytoplasmic and mitochondrial. We generated a single knockout cell line by homologous recombination in which one allele of SHMT was replaced by the neomycin phosphotransferase gene. Knockout parasites showed no difference in epimastigote growth rate or in in vitro metacyclogenesis. However, knockout parasites showed a significant decrease in both, infection index and in the number of trypomastigotes released from CHO-K1cells infected with knockout metacyclic forms.

RIC-8B é uma proteína que apresenta, in vitro, atividade de fator de troca de nucleotídeos guanina (GEF). No entanto, seu papel in vivo não é conhecido. Dados anteriores do nosso laboratório demonstraram que essa proteína interage especificamente com Gαolf, que é uma proteína G exclusiva do sistema olfatório, presente nos cílios dos neurônios olfatórios, onde ocorre a transdução de sinal ativada pelos odorantes. No camundongo adulto verificou-se, por meio de ensaios de hibridização in situ, que RIC-8B está presente somente em regiões de expressão de Gαolf: no epitélio olfatório maduro e no núcleo estriado do sistema nervoso central. Para avaliar a função fisiológica de RIC-8B in vivo, resolvemos gerar uma linhagem de camundongo knockout para Ric-8B. Verificamos que a linhagem é inviável devido à letalidade dos embriões já em fases precoces do desenvolvimento (por volta de E8,5 e E9,0). A coloração de embriões com X-gal mostra que RIC-8B é especificamente expressa em regiões que darão origem ao sistema nervoso, como na região ventral do tubo neural, e em regiões cefálicas. Interessantemente, mostramos que RIC-8B é expressa na placa do assoalho do tubo neural, de uma maneira muito semelhante ao padrão de expressão de Sonic Hedgehog (SHH), que apresenta um papel fundamental para a organização do sistema nervoso, entre outras funções. Nossos resultados indicam, portanto, que RIC-8B desempenha um papel crucial durante a embriogênese, e que este papel pode estar relacionado com o papel exercido por SHH. Além disso, como a via de sinalização de SHH ocorre em cílios primários nas células alvo, nossos dados levantam a interessante possibilidade de que RIC-8B apresenta funções relacionadas a cílios, tanto no camundongo adulto (neste caso nos cílios dos neurônios olfatórios) como no embrião (neste caso nos cílios primários). / RIC-8B is a protein that, in vitro, acts as a guanine nucleotide exchange factor (GEF). However, its role in vivo remains unknown. Previous data from our laboratory demonstrated that this protein is able to interact specifically with Gαolf, a G protein found only in the olfactory system. This G protein is located in the cilia from olfactory neurons, where odorant signaling occurs. In situ hybridization experiments showed that RIC-8B, in adult mice, is expressed only in regions where Gαolf is expressed, such as the olfactory epithelium and the nucleus striatum in the central nervous system. In order to determine the function of RIC-8B in vivo, we decided to generate a knockout mouse strain for Ric-8B. We found that this strain is not viable due to the lethality of embryos in the early stages of development (around days E8.5 and E9.0). X-gal staining of embryos shows that RIC-8B is specifically expressed in regions that originate the nervous system, such as the ventral neural tube and also cephalic regions. Interestingly, we show that RIC-8B is restrictedly expressed in the floor plate of the neural tube, in a pattern that is very similar to the one shown by Sonic Hedgehog (SHH). The SHH protein plays a fundamental role in the organization of the nervous system, among other functions. Therefore, our results indicate that RIC-8B plays an essential role during the embryogenesis, and that this role can be related to the role played by SHH. Furthermore, because the SHH signaling pathway occurs in primary cilia in the target cells, our data raise the interesting possibility that the role played by RIC-8B is related to ciliary functions, both in adult mice (in this case, in olfactory cilia), and in the embryo (in this case, in primary cilia)

RIC-8B é um fator trocador de nucleotídeo de guanina (GEF) predominantemente expresso em neurônios olfatórios maduros de camundongos adultos. Trabalhos desenvolvidos em nosso laboratório mostraram que RIC-8B interage com Gαolf e Gγ13, duas subunidades de proteína G que estão enriquecidas nos cílios dos neurônios olfatórios, onde participam da transdução do sinal de odorantes. In vitro, RIC-8B é capaz de amplificar a sinalização de receptores olfatórios através de Gαolf, no entanto, seu papel fisiológico ainda é desconhecido. Para determinar a função desempenhada por essa proteína in vivo, nós utilizamos a tecnologia de Gene Trap com o objetivo de produzir um camundongo knockout para Ric-8B. Apesar de a expressão de Ric-8B ser restrita a poucos tecidos no camundongo adulto, descobrimos que homozigotos para a mutação em Ric-8B são inviáveis e morrem por volta do dia embrionário E10,5. Além disso, são menores e apresentam evidente falha no fechamento do tubo neural na região cranial (exencefalia). Utilizamos o gene repórter β-galactosidase expresso pelo alelo mutado para determinar o padrão de expressão de Ric-8B em embriões durante o desenvolvimento. Observamos que, no estágio E8,5, Ric-8B é expresso nas pregas neurais da região cefálica e na notocorda. De E9,5 a E12,5, a expressão de Ric-8B é detectada predominante no assoalho da placa. Esse padrão de expressão se assemelha ao de outro gene importante para a embriogênese, Sonic hedgehog (Shh). SHH é um morfógeno diretamente responsável pela padronização dorsoventral do sistema nervoso central e sua sinalização depende de cílio primário. Cílio primário é uma organela baseada em microtúbulos que se projeta da superfície da maioria das células de mamíferos e funciona como um centro de sinalização intracelular. Nossos dados mostram que fibroblastos embrionários Ric-8B-/- formam cílios primários, assim como alguns tecidos do embrião. Além disso, não encontramos alterações na sinalização de Shh em embriões homozigotos mutantes. No entanto, observamos que esses embriões apresentam apoptose aumentada em células migratórias da crista neural cranial. Shh é importante para a sobrevivência de células da crista neural migratória, sugerindo um possível papel para Ric-8B a downstream da sinalização de SHH. / Ric-8B is a guanine nucleotide exchange factor (GEF) which is predominantly expressed in mature olfactory sensory neurons in adult mice. We have previously shown that RIC-8B interacts with both Gαolf and Gγ13, two G protein subunits, which are enriched in olfactory cilia and are required for odorant signal transduction. In vitro, RIC-8B is able to amplify odorant receptor signaling through Gαolf, however, its physiological role remains unknown. To determine the role played by RIC-8B in vivo we used the Gene trap technology to generate a Ric-8B knockout mouse. We found that, despite the limited distribution of Ric-8B gene expression in adult mice, Ric-8B homozygous mutants are not viable and die around the E10,5 stage. Mutant embryos are also smaller and fail to close the neural tube at the cranial region (exencephaly). We used the activity of the β-galactosidase reporter gene to determine the pattern of expression of the Ric-8B gene in heterozygous embryos. At E8,5 the Ric-8B gene is expressed in the notochord and neural folds of the cephalic regions. From E9,5 to E12,5 Ric-8B is predominantly expressed in the floor plate, in a pattern that strongly resembles the one shown by Sonic hedgehog (Shh). SHH is a morphogen directly responsible for the dorsoventral patterning of the central nervous system and its signaling depends on primary cilia. Primary cilia are microtubule-based organelles that protrude from the surface of mammalian cells and act as a signaling center. We show that Ric-8B-/- embryonic fibroblasts and some embryonic tissues grow primary cilia normally. In addition, we did not find alterations in the SHH signaling of homozygous mutants. Instead, we found an increased apopotosis in migratory cells of the cranial neural crest in these embryos. Shh is an important factor to survival of neural crest cells, suggesting a role for RIC-8B downstream of the SHH signaling.

Die Familie der G-Protein-gekoppelten Rezeptoren (GPCRs) bildet die größte Gruppe von Membranrezeptoren im menschlichen Organismus. Für viele GPCRs sind bisher die physiologischen Funktionen nicht bekannt. Das biologische Verständnis der Funktionen im menschlichen Organismus dieser sogenannten „orphan“ GPCRs (oGPCRs) hat, aufgrund möglicher kausaler Beteiligung an der Pathogenese von Erkrankungen sowie deren therapeutische Beeinflussbarkeit, hohe medizinische Relevanz. Die GPCRs der P2Y12-ähnliche Rezeptorgruppe besitzen eine große physiologische Bedeutung bei der Thrombozytenaggregation und der Induktion der Migration von immunokompetenten Zellen in Schädigungsgebiete. Der ADP-Rezeptor P2Y12 kann durch verschiedene pharmakologische Wirkstoffe beeinflusst werden, was bereits klinisch-therapeutisch genutzt wird. Diese Gruppe von GPCRs enthält jedoch auch Mitglieder, deren Funktionen völlig unbekannt sind. Einer dieser oGPCRs ist der GPR34. Ziel dieser Arbeit war es, mittels verschiedener in-vitro-Methoden und anhand eines GPR34-defizienten Mausstamms die physiologische Relevanz dieses P2Y12-ähnlichen Rezeptors zu analysieren. Dazu wurde ein GPR34-Knockout-Mausmodell etabliert. Die GPR34-Defizienz hatte keinen wesentlichen Einfluss auf die Entwicklung, Morphologie, das Wachstum oder die Fertilität bei Mäusen. Die Ergebnisse aus Immunisierungs– und Infektionsstudien zeigten jedoch, dass dieser evolutionär hoch konservierte Rezeptor eine wichtige Funktion in der Feinkontrolle der zellulären Immunabwehr ausübt. Neben einer verstärkten Antwort im Delayed-type Hypersensitivity (DTH)-Test war die Abwehr einer Cryptococcus-Infektion in diesem GPR34-defizienten Tiermodell beeinträchtigt. Signifikant erhöhte Zytokinspiegel nach Antigen- bzw. Pathogenexposition deuteten auf eine gestörte Immunregulation in GPR34-defizienten Mäusen hin. Weiterführende Untersuchungen sollten sich der Identifizierung des endogenen Agonisten und der Funktion des GPR34 bei der Koordinierung der zellulären Immunreaktion widmen.

Acetylcholinesterase (AChE) effectively hydrolyzes acetylcholine (ACh). The inhibition of AChE is generally lethal and mice without AChE in all tissues (AChE KO) have severe impairments. In the brain, AChE is anchored in the plasma membrane by proline-rich membrane anchor (PRiMA), while in the muscles, AChE is anchored by collagen Q (ColQ) in the basal lamina. We report here that the PRiMA KO mice, in which AChE is essentially eliminated in the brain, show very little changes in behavior despite an excess of ACh in the brain and adaptation of ACh receptors comparable to those seen in AChE KO mice. Moreover, when AChE cannot interact with ColQ and PRiMA, the phenotype resembles that of AChE KO mice, but the biochemical changes in the brain are similar to those in PRiMA KO mice. PRiMA KO mice also differ from other AChE-deficit mice strains in their responses to AChE inhibitor. Our results suggest that AChE in the peripheral tissues is the major target of AChE inhibitors and AChE absence in the peripheral tissues is the leading cause of the phenotype of AChE KO mice.

BIN1 est une protéine qui tubule les membranes. Elle est composée de plusieurs domaines : un domaine BAR, qui lie les membranes et possède une propriété de tubulation; un motif PI qui lie les phophoinositides et est uniquement exprimé dans le muscle squelettique; un domaine CLAP qui lie la clathrin et AP2 et qui n'est présent que dans les isoformes de BIN1 exprimées dans le cerveau; un domaine MBD impliqué dans la liaison à c-Myc; et un domaine SH3 impliqué dans les interactions avec les protéines riches en prolines. BIN1 est une protéine ubiquitaire, et l'organe où elle est le plus fortement exprimée est le muscle squelettique. Il a été montré que des mutations dans l'amphiphysine 2/BIN1 causent une myopathie centronucléaire récessive (ARCNM, OMIM 255200). Les mutations trouvées chez les patients sont réparties dans tous les domaines de la protéine, et deux d'entre elles aboutissent à un codon stop prémature dans l'exon 20, dernier exon de la protéine. Le motif PI, codé par l'exon 11, est régulé positivement pendant la myogenèse. Le but de cette recherche était de mieux comprendre le rôle de BIN1 dans le muscle sain et dans le cas de myopathie centronucléaire. Nous avons donc utilisé la technique de recombinaison homologue ciblée dans les cellules ES pour générer deux lignées de souris knockout: BIN1 exon 11 (délétion de l'exon 11) et BIN1 exon 20 (délétion de l'exon 20). La délétion de l'exon 20 détruit le domaine SH3, qui permet l'interaction de BIN1 avec différentes protéines, dont la dynamine 2, et induit une baisse considérable de l'expression de BIN1 au niveau protéique. Les délétions totales et spécifiques du muscle de l'exon 20 provoquent une létalité périnatale. Nous avons observé une perturbation de l'organisation des tubules T chez les souris KO, ce qui montre l'importance de BIN1 pendant la biogenèse des tubules T. Cependant, l'induction de la délétion chez la souris adulte n'a affecté ni la fonction ni l'organisation du muscle. Pour comprendre le rôle du motif PI, qui est spécifique du muscle, nous avons caractérisé les souris BIN1 KO exon 11. Même à 12 mois, la fonction du muscle n'était pas compromise chez ces souris. En revanche, nous avons observé des problèmes de régénération du muscle squelettique. Ce travail révèle, qu'in vivo, BIN1 est nécessaire pour la biogenèse des tubules T, mais pas indispensable pour le maintien du muscle. D'autre part, le domaine PI, spécifique du muscle, est impliqué dans la régénération musculaire. Sa function dans les muscles est régulée finement par l’expression de différentes isoformes et par des interactions intra-moléculaires. Comprendre ces caractéristiques nous aiderait à développer de nouvelles thérapies pour les patients atteints de ARCNM et de MD. / BIN1 is a membrane tubulating protein and it consists of the BAR domain which binds membranes and has tubulating property; the PI motif which binds phosphoinositides and is expressed only in skeletal muscle; the CLAP domain binds clathrin and AP2 and is present exclusively in brain isoforms of BIN1; the MBD is involved in c-Myc binding and the SH3 domain is involved in interactions with prolin-rich proteins. BIN1 is an ubiquitously expressed protein with the highest expression in skeletal muscle. Mutations in amphiphysin 2 / BIN1 were found to cause autosomal recessive centronuclear myopathy (ARCNM, OMIM 255200). Mutations in patients were found in all the protein domains and include two mutations leading to a premature stop codon in the last exon 20. The PI motive, encoded by exon 11, is upregulated during myogenesis. The aim of this research was to better understand the role of BIN1 in healthy muscle and in the pathology of CNM. For this purpose, by using targeted homologous recombination in ES cells, we generated two knockout mouse models: BIN1 exon 11 and BIN1 exon 20, with exon 11 and 20 deleted, respectively. The deletion of exon 20 disrupts the SH3 domain, involved in interactions with different proteins, amongst which is dynamin 2 and induced a considerable loss of the total BIN1 protein expression. The total and muscle specific deletions of exon 20 were perinatally lethal. A disrupted T-tubules organization was observed in knockout mice, showing an importance of BIN1 during the T-tubule biogenesis. Interestingly, deletion induced in adult mice did not affect muscle function and organization. In order to understand the role of the muscle specific PI motif, we characterized the BIN1 exon 11 KO mice. Even at 12 months of age the muscle function in mice was not compromised by this deletion. However, further examination showed impairment of skeletal muscle regeneration. This work revealed that in vivo, BIN1 is necessary during the T-tubules biogenesis and dispensable for muscle maintenance, whereas the skeletal muscle specific PI motif of BIN1 is involved in muscle regeneration. Its function in muscle is tightly regulated by isoform switch and intramolecular binding. Understanding these features will help us step forward towards successful therapy in ARCNM and MD patients.

Introdução: Os fitoesteróis (FE) são reconhecidos por reduzirem a concentração plasmática de LDL-colesterol, sendo importantes coadjuvantes no tratamento da hipercolesterolemia moderada. Entretanto, estudos publicados recentemente demonstram resultados conflitantes em relação à eficiência dos FE na prevenção da aterosclerose. Além disso, algumas investigações evidenciaram que o aumento da concentração plasmática de FE está positivamente relacionado ao risco de desenvolvimento de aterosclerose. Com a finalidade de elucidar a sua ação sobre esses parâmetros, o objetivo deste estudo foi avaliar os efeitos da suplementação de FE no desenvolvimento da aterosclerose em camundongos com ablação gênica para o receptor de LDL (LDLr-KO). Métodos: Os animais foram alimentados durante 16 semanas, com dieta rica em gordura (40% do valor calórico total da dieta), suplementada (grupo FE; 2%, n=10) ou não (Controle; n=10) com FE. Foram avaliadas as concentrações plasmáticas e hepáticas de colesterol, triglicérides, FE (beta-sitosterol, campesterol e latosterol). Na aorta dos animais, determinaram-se as concentrações de colesterol total, colesterol livre e éster e FE, além do infiltrado de macrófagos e infiltrado de lípides. Nos macrófagos do peritôneo dos animais, os quais assemelham-se aos presentes na artéria, avaliou-se a expressão de RNA mensageiro dos genes envolvidos no efluxo e influxo de colesterol (ABCA1, ABCG1, LOX1 e CD36). Também determinou-se as concentrações de FE no intestino e baço dos animais. Resultados: Conforme esperado, o consumo de FE induziu elevação plasmática dos principais FE, campesterol e de beta-sitosterol, reduzindo a concentração de colesterol no plasma. Houve aumento nas concentrações hepáticas de triglicérides e FE, entretanto, não foram observadas diferenças entre os grupos nas expressões de RNA mensageiro de genes lipolíticos (CPT, PPAR alfa) e lipogênicos (SREBP1-c, MTP, LXR e PPAR gamma) no fígado. Não houve, também, alteração no SREBP2, gene relacionado à síntese de colesterol. O conteúdo de colesterol total na artéria foi menor nos animais do grupo FE, não diferindo entre as formas livre e éster. As concentrações de FE na artéria foram iguais entre os grupos. A área de lesão no grupo FE foi menor em relação ao grupo-controle. A suplementação com FE induziu redução na expressão de RNA mensageiro de ABCG1, não interferindo na expressão dos outros genes estudados na artéria. Conclusão: Os achados deste estudo demonstram que a elevação de FE no plasma não induziu o seu acúmulo na parede da artéria e preveniu o desenvolvimento da aterosclerose / Introduction: The plasma cholesterol-reducing effect of hytosterols (PS) is well recognized and they are considered important adjuncts in the treatment of moderate hypercholesterolemia. However, recent studies have shown conflicting results regarding the efficiency of PS in the prevention of atherosclerosis. In addition, some studies showed that the increase in plasma PS concentration is positively correlated to the risk of atherosclerosis. In order to elucidate its action on these parameters, the objective of this study was to evaluate the effects of PS supplementation in the development of atherosclerosis in LDL receptor knock-out mice (LDLr -KO). Methods: The animals were fed during 16 weeks with high fat diet (40 % of calories as fat), supplemented (PS group, 2%, n = 10) or not (Control, n = 10) with PS. Plasma and liver concentrations of cholesterol, triglycerides, PS (beta - sitosterol, campesterol and lathosterol) were evaluated. In the aorta of the animals, the concentrations of total cholesterol, free cholesterol, cholesterol ester and PS, besides macrophage and lipids infiltration were determined. The mRNA expression of genes involved in cholesterol efflux and influx (ABCA1, ABCG1, LOX1 and CD36) were evaluated, in peritoneum macrophage, which resemble those present in the artery. It was also determined the intestine and spleen PS concentrations from the animals of both groups. Results: As expected, PS supplementation induced increasing plasma concentration of the main PS, campesterol and beta -sitosterol and reducing cholesterol plasma concentration. It was observed an increase so intestine and spleen PS concentrations. There was an increase in hepatic triglyceride concentrations and PS, however, no differences were observed between the groups of hepatic mRNA expression of lipolytic (CPT, PPARalfa) and lipogenic genes (SREBP1c, MTP, CPT, LXR, and PPAR gamma). There was no difference on SREBP2, gene related to cholesterol synthesis. The content of total cholesterol in the artery was lower in PS group animals however did not differ between the free and ester forms. Artery PS concentrations did not differ between groups. The lesion area in the PS group was lower than in the control group. PS supplementation induced reduction in mRNA expression of ABCG1, not affecting the expression of other genes studied in artery. Conclusion: The findings of this study demonstrate that the elevation of plasma PS concentration did not induce its accumulation in the arterial wall and prevented the development of atherosclerosis