SIP470, a putative tobacco lipid transfer protein, was identified in a yeast two-hybrid screen to interact with SABP2. SABP2 is a critical role in SA-mediated signaling in tobacco and other plants. In vitro studies using purified recombinant SIP470 confirmed that it is a lipid binding protein. In an attempt to determine its role in mediating stress responses, Arabidopsis T-DNA insertion knockout lines lacking SIP470 homolog were used for the analysis. These mutant plants were defective in basal resistance against microbial pathogens. Expression of defense gene PR-1 was also delayed in these mutant plants. Interestingly, these mutant plants were not defective in inducing systemic acquired resistance. Besides biotic stress, these mutant plants also showed increased susceptibility to abiotic stresses. To directly study the role of SIP470 in tobacco plants, transgenic tobacco lines, with reduced levels of SIP470 expression, were generated using RNAi and transgenic lines overexpressing SIP470 were also generated.

All plants have a protection against the surrounding environment called a cuticle coating. When this cuticle coating is constructed it is believed that the family of protein called lipid transfer proteins (LTPs) is involved. The LTPs are small and cysteine rich. In Marchantia polymorpha the groups of LTPs called LTPd and LTPg can be found. 8 and 4 in each group respectively. In the genes of LTPd there is an intron placed downstream of the start codon. Firstly, a sequence database search was performed and LTPd2 and LTPd3 were chosen for further experiments in this study. Secondly, a control that the intron was present in the samples were done by preforming a PCR reaction of cDNA from isolated RNA taken from untreated Marchantia polymorpha. A gel electrophoresis of the product was also performed. Lastly, the amount of alternative splicing in LTPd2 and LTPd3 from Marchantia polymorpha after treated with cold and dehydration were studied using quantitative PCR. For the qPCR MpACT and the exon of respective gene were used as references. The ΔCt values and the expression fold (2ΔΔCt) calculated from the qPCR results showed that most of the transcript with introns preserved were upregulated after subjected to stress. Only the intron in MpLTPd2 and MpLTPd3 with MpACT as reference showed a small downregulation after the cold treatment. The intron in MpLTPd3 with MpLTPd3s exon as reference didn’t show any difference. None of the intron transcript in any of the genes on the other hand showed any significant difference in the alternative splicing. This could be because of small sample groups when the test was performed. In conclusion, there were no significant difference in intron expression between treated and control samples. Therefore, nothing can be said about the change in alternative splicing in MpLTPds after cold and dehydration treatments.

Orientador: Helena Coutinho Franco de Oliveira / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-08T01:57:23Z (GMT). No. of bitstreams: 1 Salerno_AlessandroGonzales_D.pdf: 2445286 bytes, checksum: e866a42ced694e2b27c4f3217df48712 (MD5) Previous issue date: 2007 / Resumo: Neste trabalho investigamos o efeito da expressão de genes envolvidos no transporte e redistribuição de triglicérides das lipoproteínas plasmáticas, a apolipoproteína (apo) CIII e a proteína de transferência de colesteril éster (CETP), sobre o metabolismo de triglicérides pós-prandial e sobre a formação de depósitos adiposos regionais em camundongos geneticamente modificados. Podemos resumir nossos achados da seguinte maneira: a expressão da CETP leva ao aumento da trigliceridemia pós prandial; nenhuma alteração da absorção intestinal de gorduras e de secreção hepática de VLDL (lipoproteína de densidade muito baixa); redução da atividade da lipoproteína lipase e retardo na remoção plasmática de lipoproteínas ricas em triglicérides (TG). Mediante longo prazo de dieta rica em gordura, a super-expressão da CETP também provoca redução da gordura subcutânea, redução do tamanho do adipócito e da concentração plasmática de leptina em camundongos transgênicos hipertrigliceridêmicos que super-expressam a apo CIII. Por outro lado, a superexpressão de apo CIII não afeta o tamanho dos depósitos adiposos viscerais e subcutâneos na vigência de dieta pobre em gordura, porém causa aumento dos depósitos adiposos viscerais e subcutâneos e do tamanho dos adipócitos viscerais e concentração de leptina mediante dieta rica em gordura. Os camundongos que super-expressam a apo CIII não apresentaram diferenças na adiposidade quando sob dieta pobre em gordura devido a um aumento do metabolismo corporal associado a maior velocidade de respiração mitocondrial de repouso. Porém, quando submetidos à dieta rica em gordura, acumulam mais tecido adiposo visceral e subcutâneo, tornando-se mais obesos que os controles. A expressão da CETP neste contexto metabólico de hipertrigliceridemia neutraliza o efeito adipogênico da apo CIII / Abstract: Cholesteryl ester transfer protein (CETP) promotes the exchange between cholesteryl ester (CE) from HDL and triglycerides (TG) from TG rich lipoproteins. The overexpression of apolipoprotein (apo) CIII in transgenic mice causes hypertriglyceridemia due to decreased TG rich lipoprotein plasma removal rate. In this work we investigated whether CETP expression and apo CIII expression affect the post-prandial TG levels and diet induced visceral adipose tissue formation in genetically modified mice. Results showed that the expression of CETP lead to augmented post-prandial TG levels, similar intestinal fat absorption and hepatic TG and cholesterol secretion rates, diminished TG rich lipoproteins plasma removal rates and reduced lipoprotein lipase activity. These findings indicate that the levels of circulating CETP modulate dietary fat tolerance. Under long-term high fat diet, the expression of CETP reduced the subcutaneous adipose depot, visceral adipocyte size and plasma leptin levels of hypertriglyceridemic mice overexpressing the apo CIII. On the other hand, under low fat diet, the apo CIII transgenic mice presented visceral and subcutaneous adipose depots similar to the wild type mice and increased body metabolic rate and mitochondrial resting respiration rates. However, under high fat diet, the apo CIII transgenic mice showed increased visceral and subcutaneous adipose tissue, visceral adipocyte size and plasma leptin levels and no differences in body energy dissipation (rectal temperature and mitochondrial resting respiration). In conclusion, the elevation of plasma apo CIII levels aggravates diet-induced obesity and the expression of physiological levels of circulating CETP reverses this adipogenic effect, indicating a novel role for CETP in modulating adiposity / Doutorado / Fisiologia / Doutor em Biologia Funcional e Molecular

Die durch den obligat biotrophen Protisten Plasmodiophora brassicae hervorgerufene Pflanzenkrankheit Kohlhernie verursacht weltweit hohe ökonomische Verluste. Bis heute gibt es keine effektiven Möglichkeiten, diese Pflanzenkrankheit zu bekämpfen. Eine Analyse der Genexpression in infizierten Wurzeln im Vergleich zu nicht infizierten Wurzeln ergab, dass die Gene für Lipid-Transfer-Proteine während der gesamten Krankheitsentwicklung differentiell reguliert sind. Über die Funktionen von Lipid-Transfer-Proteinen in Pflanzen wird noch spekuliert. Diskutiert wird dabei eine Funktion bei der Anpassung an verschiedene abiotische Stressfaktoren, bei der Pathogenabwehr sowie bei dem Transfer von Lipiden. In dieser Arbeit wurden transgene Pflanzen generiert, in denen die pathogenbedingte LTP-Genregulation umgekehrt ist. Es wurden transgene A. thaliana Pflanzen erzeugt, die die Gene LTP1, LTP3, LTP4, AT1G12090 sowie AT2G18370 überexprimieren und die Genexpression von AT4G33550 sowie AT1G62510 reprimieren. Die Regulation der LTP-Genexpression erfolgte dabei durch den wurzel- und keimlingsspezifischen Promotor Pyk10. Zusätzlich wurden in dieser Arbeit auch T-DNA-Insertionsmutanten für die Gene AT1G12090, AT2G18370, AT3G22620, AT5G05960, LTP3 sowie LTP4 untersucht. Mittels semiquantitativer Expressionsanalyse konnte die Modulation der LTP-Genexpression in den LTP-Mutanten bestätigt werden. Darüber hinaus konnte gezeigt werden, dass die Modulation der Expression eines LTP-Gens auch die Expression anderer LTP-Gene beeinflusst. Die phytopathologischen Analysen der LTP-Mutanten hinsichtlich der Entwicklung der Pflanzenkrankheit Kohlhernie ergab, dass die Überexpression der Gene LTP1, LTP3 sowie AT2G18370 und die Repression der Expression von AT1G62510 eine verringerte Anfälligkeit für diese Krankheit bewirkt. Die verstärkte Expression der Gene LTP1, LTP3, LTP4, AT1G12090 sowie AT2G18370 resultiert außerdem in einer verringerten Symptomentwicklung infolge einer Pseudomonas syringae-Infektion. Die verringerte Expression des Gens AT4G33550 führt hingegen zu einer größeren Anfälligkeit für eine P. brassicae Infektion; die Infektion mit P. syringae wird dadurch aber nicht beeinflusst. Die physiologische Charakterisierung der LTP-Mutanten umfasste die Analyse des Pflanzenwachstums unter Salzstress bzw. osmotischem Stress sowie die Entwicklung der Seneszenz in abgetrennten Rosettenblättern. Es konnte gezeigt werden, dass die Gene LTP1, LTP3, LTP4, AT4G33550 sowie AT1G62510 bei der Anpassung an Salzstress sowie die Gene LTP3, AT3G22620, AT4G33550 und AT1G62510 bei der Anpassung an osmotischen Stress eine Rolle spielen. Durch die Modulation der Expression der genannten Gene wird das Wachstum unter diesen Stressbedingungen sowohl positiv als auch negativ beeinflusst. Die Entwicklung der Seneszenz wird ebenfalls durch eine veränderte LTP-Genexpression (LTP1, LTP3, LTP4, AT3G22620 sowie AT4G33550) beeinflusst. Für die biochemische Charakterisierung wurden die LTP-Gene aus A. thaliana mit einem Fusionspartner in E. coli exprimiert und die resultierenden Fusionsproteine gereinigt. Diese wurden nach Abspalten des Fusionspartners hinsichtlich ihrer antimikrobiellen Aktivität und auf die Fähigkeit, Calmodulin zu binden, untersucht. Für die gereinigten Lipid-Transfer-Proteine LTP1, LTP3, LTP4, AT2G18370 sowie AT1G62510 konnte unter den bisher getesteten Versuchsbedingungen keine antimikrobielle Aktivität nachgewiesen werden. Für die Proteine LTP1, LTP3 und LTP4 konnte eine calciumunabhängige Calmodulin-Bindung nachgewiesen werden. Die Ergebnisse dieser Versuche ermöglichen keine Aussage bezüglich der genauen Funktion der einzelnen Lipid-Transfer-Proteine, geben aber Hinweise darauf, dass diese bei den entsprechenden Stress-Vorgängen eine Rolle spielen. Welche Funktion sie dabei genau erfüllen, muss in weiterführenden Analysen untersucht werden.

<p>  </p> <p>Plants synthesize and release a variety of volatile organic compounds (VOCs) that are important for their reproduction, defense, and communication. These low-molecular-weight, lipophilic molecules also serve as practical products in industries such as food additives, fragrances, colorants, nutraceuticals, and pharmaceuticals. In addition, they have agricultural applications such as sustainable methods for pest control. Therefore, identifying the biological mechanisms involved in volatile emission could help researchers develop new ways to control the timing and release of volatiles, defend against pests, and engineer the production of these valuable chemicals.</p> <p>While progress has been made in understanding plant volatile biosynthesis, their release from the cell remains incomplete. For plant VOCs to be emitted into the environment, they must move from their site of biosynthesis through the cytosol, transverse the plasma membrane, hydrophilic cell wall, and sometimes cuticle to exit the cell. It was previously shown by mathematical modeling that to achieve observed emission rates solely by diffusion, VOCs would accumulate in the cellular membranes to levels that are likely detrimental to the membrane integrity and function. Hence, it was proposed that there are biological mechanisms involved to lower VOC concentrations in membranes. In this work, we focus on the aqueous cell wall, the thickest layer among the three subcellular barriers that should act as a barrier for the diffusion of VOCs. We hypothesize that the transport of VOCs across the cell wall is facilitated by lipid transfer proteins (LTPs) which enhance the solubility of hydrophobic volatiles in the aqueous environment, prevent their back partition into the plasma membrane after entering the cell wall, and hence enhance their net diffusion. To investigate if the presence of LTPs has influence on the total VOC efflux, we use reverse-genetic, biochemical, and mathematical modeling approaches. Out of three highly expressed LTPs identified in the petunia petal, only downregulation of <em>PhLTP3</em> expression led to a decrease in VOC emission in the corresponding transgenic plants. A facilitated diffusion model was built to quantify the VOC flux difference with the presence of LTPs in the cell wall. Modeling of the steady state system revealed the facilitation of VOC flux by LTPs is greatest when the VOC concentration gradient across the cell wall is shallow, which is a physiologically relevant condition. In addition, there exists an optimal protein dissociation constant value for maximal facilitated flux, indicating the balance between the binding and the unloading of VOC is critical. With the in vitro displacement assay, the binding constants of candidate PhLTPs with VOCs were obtained and were all found to be in the µM range, which is close to our model predicted optimal value. The results revealed that LTPs, specifically PhLTP3, play a role in the export of VOCs from the plasma membrane, across the cell wall, to the cuticle.</p> <p>In our earlier mathematical model, the emission of VOCs from the petunia flowers was modeled assuming negligible mass transfer resistance on the surface of the cuticle because of their high volatility. However, the resistance imposed by the surface boundary layer was not considered. To examine if surface convection influences VOC emission, a model system which utilized a model cuticular wax film containing 2-phenylethanol (2-PE) was built to imitate the VOC emission from plant cuticle. The convection mass transfer coefficient of 2-PE emission from a model cuticular wax film was obtained by experimental data fitting and calculated from the correlation that involves Sherwood number. The obtained values that were smaller than unity indicates that the surface boundary layer imposes a higher mass transfer resistance than the model cuticle for the emission of 2-PE in the range of wind velocities investigated. The examination of petunia flowers under air flow showed increases in total emission but no significant differences in total internal pools, which indicates an increase in biosynthesis. The emission changes of individual compounds were different and does not clearly correlate to any molecular properties of the compounds.  </p>

Due to global warming, our planet will experience more extreme weather conditions. Plants can protect themselves against these abiotic stress conditions with their stress response, which includes alternative splicing of certain genes. Alternative splicing is a post-transcriptional process where a single gene gives rise to different mRNAs, which in turn produces different proteins. In plants, this is usually done by intron retention. One type of protein that may be involved in this stress response are the non-specific lipid transfer proteins (LTPs). Indeed, evidence of intron retention has been found in the LTP genes in the liverwort Marchantia polymorpha, called MpLTPd. To investigate whether this alternative splicing is caused by abiotic stress or not, I subjected the moss to two different types of stress trials, drought and cold, and compared the general expression of the intron in MpLTPd2 and MpLTPd3 from the stressed samples to samples from a moss grown under normal conditions. I found that the expression of the intron did change in the stressed moss, but none of the differences were significant. This suggests that alterative splicing in MpLTPd2 and MpLTPd3 is not caused by cold and drought and that the intron-containing protein plays no role in the protection of M. polymorpha against abiotic stress.

Orientador: Helena Coutinho Franco de Oliveira / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-11T11:46:21Z (GMT). No. of bitstreams: 1 Raposo_HelenaFonseca_M.pdf: 1257741 bytes, checksum: f53550bd6c88a5cd12f0daf241da3486 (MD5) Previous issue date: 2008 / Resumo: Os óleos de peixe e de milho são fontes de ácidos graxos poli-insaturados (PUFA) n-3 e n-6, respectivamente. Estes ácidos graxos são ligantes naturais dos receptores ativados por proliferadores de peroxissomos (PPARs) e, dessa forma, modificam a expressão de diversos genes envolvidos no metabolismo de lipídios. A proteína de transferência de colesteril-éster (CETP) é uma proteína plasmática sintetizada em vários tecidos, principalmente do fígado. A CETP participa do transporte reverso de colesterol, reduzindo HDL no plasma e aumentando o risco de aterosclerose. Este trabalho teve como objetivo investigar os efeitos dos óleos ricos em PUFA n-3 e n-6 e de fibratos (ligantes sintéticos de PPAR e agentes redutores de triglicérides) sobre a expressão e atividade da CETP. Assim, camundongos transgênicos que expressam a CETP foram tratados por duas semanas com óleo de peixe, óleo de milho ou salina, e camundongos CETP hipertrigliceridêmicos foram tratados com gemfibrozil (GEM), fenofibrato (FENO), bezafibrato (BEZA) ou veículo (control). Após os tratamentos com os PUFA, não foi verificada diferença no peso corporal, na ingestão ou no peso relativo do fígado e tecidos adiposos. Também não houve alteração das concentrações plasmáticas de glicose e triglicerídios. O óleo de peixe reduziu os níveis de ácidos graxos livres (37%) e colesterol (15%), enquanto o óleo de milho aumentou significativamente os níveis de colesterol. Comparado ao grupo salina, os camundongos tratados com óleo de milho apresentaram aumento nos níveis de leptina (30-40%). O tratamento com óleo de peixe elevou os níveis de adiponectina quando comparados com o grupo salina (27%) e com o grupo tratado com óleo de milho (31%). Dois dos três fibratos testados (FENO, GEM) induziram elevação da atividade plasmática (15-30%) e da expressão hepática de RNAm da CETP (53-75%) quando comparados ao grupo controle. FENO também reduziu a concentração plasmática de triglicérides. O óleo de peixe aumentou os níveis plasmáticos de CETP em relação aos grupos salina e óleo de milho (13-14%), efeito verificado apenas nas fêmeas. Entretanto, não foi observada alteração na expressão hepática de RNAm de CETP. Verificou-se que os tratamentos com os óleos PUFA reduziram a expressão hepática de RNAm de PPAR_ (36%) e o óleo de milho induziu aumento da expressão do fator de transcrição SREBP1 (120%) nos machos, mas não nas fêmeas. Os óleos PUFA também induziram aumento da expressão de SREBP2, porém, apenas em fêmeas. As alterações diferenciais de RNAm de PPAR_, SREBP1 e SREBP2 em cada sexo poderiam estar implicadas na resposta gênero-específica da CETP frente aos PUFA. Assim concluímos que o gene da CETP é responsivo aos agonistas sintéticos de PPAR_, e que os ácidos graxos n-3 controlam a expressão da CETP de maneira gênero-dependente e por mecanismo pós-transcricional / Abstract: Fish and corn oils are n-3 and n-6 polyunsaturated fatty acid (PUFA) sources, respectively. They are natural ligands of the peroxisome proliferator activated receptors (PPARs), thus capable of modifying the expression of several genes involved in lipid metabolism. CETP is a plasma protein synthesized in several tissues, mainly liver, which reduces plasma HDL and increases the risk of atherosclerosis. The aim of this work was to investigate the potential effects of PUFA oils and fibrates on the CETP levels. Therefore, CETP transgenic mice were treated during 2 weeks with fish oil (FO), corn oil (CO) or saline, whilst hypertrygliceridemic CETP mice were treated with gemfibrozil (GEM), fenofibrate (FENO), bezafibrate (BEZA) or vehicle (control). There were no differences in body weight, food intake and relative weight of liver and adipose tissue after PUFA or saline treatments. Also, no changes were verified in glucose and triglyceride plasma levels after both PUFA treatments. FO reduced plasma free fatty acid (37%) and cholesterol (15%) levels, whilst CO increased cholesterol mildly. Compared to saline, mice treated with CO showed an increase in leptin levels (30-40%). Treatment with FO enhanced adiponectin plasma levels when compared to saline (27%) and CO (31%). Two out of the three fibrates (FENO, GEM) induced elevation in plasma CETP activity (15- 30%) and liver mRNA expression (53-75%) when compared to control. FENO also reduced triglyceride levels. FO increased CETP plasma levels (13-14%) when compared to CO and saline, an effect verified only in females. However, no changes were observed in liver CETP mRNA expression. FO treatment decreased PPAR_ (36%) and CO increased SREBP1 liver mRNA levels (120%) in males, but not in females. PUFA treatment increased SREBP2 mRNA only in females. These distinct mRNA changes could explain genderspecific CETP response to PUFA treatments. In conclusion, CETP gene is responsive to PPAR_ agonists, and n-3 PUFA (FO) can regulate CETP expression by post-transcriptional mechanisms, in a manner dependent on the female context / Mestrado / Fisiologia / Mestre em Biologia Funcional e Molecular

Introdução: A Organização Mundial da Saúde estimou em 2015 que 23 milhões de pessoas em todo o mundo sofrem de insuficiência cardíaca (IC), com taxas de mortalidade equivalentes às do câncer. Níveis mais elevados de HDL-colesterol têm sido associados com maior sobrevivência na IC. É consensual que as várias funções protetoras da HDL devem ser exploradas além da concentração de HDL-colesterol. Transferência de lípides para HDL, mediada por proteínas de transferência CETP e PLTP, é uma etapa importante no transporte reverso de colesterol e metabolismo de HDL.,Desenvolvemos um ensaio in vitro para avaliar as transferências de lípides para a HDL, mostrando que esse fenômeno é alterado em várias condições, como na doença arterial coronária, no diabetes mellitus e pelo estilo de vida sedentário. Recentemente, tem sido descrito que a HDL transporta pequenos RNAs não codificadores de proteína, os chamados microRNAs (miRNAs). Alguns miRNAs foram descritos como reguladores críticos do metabolismo das lipoproteínas. O objetivo deste estudo foi comparar lípides plasmáticos, transferência lipídica para HDL, perfil inflamatório, miRNAs relacionados ao metabolismo de lipoproteínas obtidos de pacientes com IC e de pacientes sem IC (sem-IC). Métodos: Quarenta e oito pacientes com IC foram avaliados, 25 em classe funcional NYHA I e II (IC-I/II) e 23 em NYHA III e IV (IC-III/IV), bem como 50 pacientes sem-IC pareados por gênero e idade. Todos os pacientes com IC apresentavam uma fração de ejeção <=40%. Foram determinadas as concentrações plasmáticas de CETP, LCAT, LDL oxidada (LDLox) e atividade de paraoxonase 1 (PON-1). Transferências de lípides para a HDL foi avaliada a partir da incubação de uma nanopartícula artificial com plasma total. A expressão de miRNAs circulantes envolvidos no metabolismo das lipoproteínas também foi analisada. Resultados: Os níveis de colesterol total, LDL e HDL e triglicérides não diferiram entre os três grupos. A concentração da apolipoproteína A-I foi menor no grupo IC-I/II em comparação ao grupo sem-IC (125±23 versus 142±19; p < 0,05), enquanto que a concentração da apolipoproteína B foi menor em ICIII/ IV comparado ao sem-IC (81±35 versus 114±40; p < 0,001). A transferência de colesterol esterificado (5,44±1,76 versus 6,26±0,85), fosfolípides (19,05±2,5 versus 20,21±1,45) e de triglicérides (6,29±2,05 versus 7,40±1,47) foi menor no grupo IC-III/IV do que no grupo sem-IC (p < 0,05). No entanto, não houve diferença nas transferências entre IC-I/II e sem-IC. A concentração de LDLox foi menor em ambos os grupos com IC comparados ao sem-IC (p < 0,0001). A massa de CETP foi menor em IC-III/IV do que em IC-I/II (2,77±1,3 versus 3,78±1,3; p=0,021). A concentração de LCAT e a atividade de PON-1 não foram diferentes entre os grupos. A análise da expressão dos miRNAs circulantes miR-33a, miR-144, miR-185, miR-125, miR-758, miR-26a, miR- 106b, miR-122 e miR-30c, mostrou-se significantemente aumentada nos indivíduos com IC em comparação aos indivíduos sem-IC, ao passo que o miR- 10b foi o único encontrado diminuído na IC comparado com indivíduos sem-IC (p=0,007). Conclusão: Em pacientes com IC mais severa e sintomática da IC, o processo de transferência de lípides para a HDL está deficiente, bem como alguns dos mecanismos que o regulam, e possivelmente estas alterações influenciem no transporte reverso do colesterol e nas funções protetoras da HDL desses pacientes / Background: World Health Organization estimated that there were twentythree million subjects worldwide suffering from heart failure (HF) in 2015, with mortality rates equivalent to those of cancer. Higher HDL-cholesterol levels have been associated with longer survival in HF. It is now consensual that the various protective functions of HDL should be explored beyond HDLcholesterol. Transfer of lipids to HDL, mediated by transfer proteins CETP and PLTP, is an important step in reverse cholesterol transport and HDL metabolism. Previously, we developed an in vitro assay to test those lipid transfers and showed that transfer of cholesterol to HDL is altered in several conditions, such as coronary artery disease (CAD), diabetes and sedentary lifestyle. Recently, HDL transports small non-coding RNA molecule, called micro RNAs (miRNAs). Some miRNA are critical regulators of lipoprotein metabolism. The aim of this study was compare plasma lipids, lipid transfers to HDL, inflammatory profile, miRNAs related to plasma lipids from patients with HF with those from patients with without HF (non-HF). Methods: Forty-eight HF patients were studied, 25 with functional class NYHA I and II (HF I/II) and 23 with NYHA III and IV (HF III/IV), as well as 50 non-HF patients matched for gender, age and BMI. All HF had ejection fraction <= 40%. CETP, LCAT, oxidized LDL (oxLDL) and paraoxonase 1 (PON-1) activity were determined. Transfers of lipids from a donor artificial nanoparticle to HDL was determined by an in vitro assay in which the emulsion was incubated with whole plasma. Expression of circulating miRNAs involved in cholesterol metabolism was also analyzed. Results: Total, LDL and HDL cholesterol and triglycerides did not differ among the 3 groups. Apolipoprotein A-I was lower in NYHA I/II group compared to non- HF (125±23 versus 142±19; p < 0.05) and apo B was lower in NYHA III/IV group compared to non-HF (81±35 versus 114±40, p < 0.001). The transfer of esterified cholesterol (5.44±1.76 versus 6.26±0.85), phospholipids (19.05±2.5 versus 20.21±1.45) and of triglycerides (6.29±2.05 versus 7.40±1.47) to HDL was lower in HF-III/IV than in non-HF (p < 0.05), but lipid transfers were not different between HF-I/II and non-HF. oxLDL was lower in both HF groups compared to non-HF (p < 0.0001). CETP mass was lower in HF-III/IV than in HF-I/II (2.77±1.3 versus 3.78±1.3; p=0.021). LCAT and PON-1 activity was not different among the groups. Regarding to miRNA, miR-33a, miR-144, miR-185, miR-125, miR- 758, miR-26a, miR-106b, miR-122 e miR-30c were significantly increased in HF compared to non-HF subjects, whereas miR-10b was the only one found to be decreased in HF compared to non-HF subjects (p=0.007). Conclusion: In patients with the more severe and symptomatic HF, the lipid transfer to HDL is deficient, as well as some mechanisms that regulate it, and possibly these changes influence reverse cholesterol transport and the protective functions of HDL in these patients

Les données épidémiologiques montrent une association inverse entre les taux de HDL-cholestérol (HDL-C) et le risque d'évènements cardiovasculaires. Des traitements ayant montré une augmentation significative du HDL-C, comme les inhibiteurs de la protéine de transfert des esters de cholestérol, devraient donc permettre de réduire le risque cardio-vasculaire. En utilisant différentes techniques de modélisation, nous avons tenté de quantifier l'efficacité attendue sur les événements cardiovasculaires de l'un d'entre eux, le dalcétrapib, ne disposant que de données pharmacocinétiques et pharmacodynamiques. Tout d’abord, afin d'établir la relation pharmacocinétique / pharmacodynamique entre les concentrations et la modification de HDL-C, nous avons analysé les données individuelles des patients dyslipidémiques par une approche de population. Une hausse moyenne de HDL-C de 26.4 % par rapport au placebo était alors anticipée. Nous avons ensuite tenté de corréler l'effet observé sur l'HDL-C et l'effet clinique à partir de données d'autres études par méta-régression des essais évaluant l'effet des principaux hypolipémiants en prévention secondaire. Cette modélisation n'a pas permis de montrer de corrélation entre le changement de l’HDL-C (P5 P95 :-3.0 et 36 %) et la réduction du risque cardiovasculaire. Une analyse de sensibilité par type de traitement suggère qu'une même hausse de HDL-C entre deux classes thérapeutiques pourrait se traduire par un effet clinique dissemblable, indiquant que HDL-C ne peut pas être utilisé comme critère intermédiaire puisqu'il ne serait pas un prédicteur indépendant du risque cardiovasculaire / Epidemiological data demonstrate an inverse correlation between HDL-cholesterol (HDL-C) levels and cardiovascular risk. Therefore, drugs as cholesteryl ester transfer protein (CETP) inhibitors that lead to a significant HDL-C increase are believed to reduce the occurrence of coronary events. We aimed to evaluate the clinical efficacy of one CETP inhibitor, dalcetrapib, by using various modeling techniques while only pharmacokinetic (PK) and pharmacodynamlc (PD) data were available. First, we analyzed individual data from dyslipidemic patients using a population approach in order to establish the PK/PD relationship between dalcetrapib concentrations and HDL-C change. The results show that an average raise of 26.4 % is expected in comparison to placebo with the 5th (P5) and 95th (P95) percentile of the mean average at 20.7 % and 31.9 % respectively. The increase in HDL-C is explained by a delayed catabolism following the transfer inhibition of cholesterol ester from HDL to Apo-B rich lipoproteins. We endeavored then to correlate HDL-C increase to coronary events by using a meta-regression analysis on randomized trials that evaluated the clinical efficacy of main dyslipidemic drugs on coronary events in secondary prevention. The modeling did not show a statistical association between HDL-C change (P5-P95:-3.0 and 36 %) and coronary risk reduction. A sensitivity analysis by drug class suggests that the same HDL-C increase resulting from different mechanisms of action may not impact the cardiovascular risk in the same way. This would indicate that HDL-C could not be used as a risk marker since it might not be an independent predictor of cardiovascular risk

Introdução: A Organização Mundial da Saúde estimou em 2015 que 23 milhões de pessoas em todo o mundo sofrem de insuficiência cardíaca (IC), com taxas de mortalidade equivalentes às do câncer. Níveis mais elevados de HDL-colesterol têm sido associados com maior sobrevivência na IC. É consensual que as várias funções protetoras da HDL devem ser exploradas além da concentração de HDL-colesterol. Transferência de lípides para HDL, mediada por proteínas de transferência CETP e PLTP, é uma etapa importante no transporte reverso de colesterol e metabolismo de HDL.,Desenvolvemos um ensaio in vitro para avaliar as transferências de lípides para a HDL, mostrando que esse fenômeno é alterado em várias condições, como na doença arterial coronária, no diabetes mellitus e pelo estilo de vida sedentário. Recentemente, tem sido descrito que a HDL transporta pequenos RNAs não codificadores de proteína, os chamados microRNAs (miRNAs). Alguns miRNAs foram descritos como reguladores críticos do metabolismo das lipoproteínas. O objetivo deste estudo foi comparar lípides plasmáticos, transferência lipídica para HDL, perfil inflamatório, miRNAs relacionados ao metabolismo de lipoproteínas obtidos de pacientes com IC e de pacientes sem IC (sem-IC). Métodos: Quarenta e oito pacientes com IC foram avaliados, 25 em classe funcional NYHA I e II (IC-I/II) e 23 em NYHA III e IV (IC-III/IV), bem como 50 pacientes sem-IC pareados por gênero e idade. Todos os pacientes com IC apresentavam uma fração de ejeção <=40%. Foram determinadas as concentrações plasmáticas de CETP, LCAT, LDL oxidada (LDLox) e atividade de paraoxonase 1 (PON-1). Transferências de lípides para a HDL foi avaliada a partir da incubação de uma nanopartícula artificial com plasma total. A expressão de miRNAs circulantes envolvidos no metabolismo das lipoproteínas também foi analisada. Resultados: Os níveis de colesterol total, LDL e HDL e triglicérides não diferiram entre os três grupos. A concentração da apolipoproteína A-I foi menor no grupo IC-I/II em comparação ao grupo sem-IC (125±23 versus 142±19; p < 0,05), enquanto que a concentração da apolipoproteína B foi menor em ICIII/ IV comparado ao sem-IC (81±35 versus 114±40; p < 0,001). A transferência de colesterol esterificado (5,44±1,76 versus 6,26±0,85), fosfolípides (19,05±2,5 versus 20,21±1,45) e de triglicérides (6,29±2,05 versus 7,40±1,47) foi menor no grupo IC-III/IV do que no grupo sem-IC (p < 0,05). No entanto, não houve diferença nas transferências entre IC-I/II e sem-IC. A concentração de LDLox foi menor em ambos os grupos com IC comparados ao sem-IC (p < 0,0001). A massa de CETP foi menor em IC-III/IV do que em IC-I/II (2,77±1,3 versus 3,78±1,3; p=0,021). A concentração de LCAT e a atividade de PON-1 não foram diferentes entre os grupos. A análise da expressão dos miRNAs circulantes miR-33a, miR-144, miR-185, miR-125, miR-758, miR-26a, miR- 106b, miR-122 e miR-30c, mostrou-se significantemente aumentada nos indivíduos com IC em comparação aos indivíduos sem-IC, ao passo que o miR- 10b foi o único encontrado diminuído na IC comparado com indivíduos sem-IC (p=0,007). Conclusão: Em pacientes com IC mais severa e sintomática da IC, o processo de transferência de lípides para a HDL está deficiente, bem como alguns dos mecanismos que o regulam, e possivelmente estas alterações influenciem no transporte reverso do colesterol e nas funções protetoras da HDL desses pacientes / Background: World Health Organization estimated that there were twentythree million subjects worldwide suffering from heart failure (HF) in 2015, with mortality rates equivalent to those of cancer. Higher HDL-cholesterol levels have been associated with longer survival in HF. It is now consensual that the various protective functions of HDL should be explored beyond HDLcholesterol. Transfer of lipids to HDL, mediated by transfer proteins CETP and PLTP, is an important step in reverse cholesterol transport and HDL metabolism. Previously, we developed an in vitro assay to test those lipid transfers and showed that transfer of cholesterol to HDL is altered in several conditions, such as coronary artery disease (CAD), diabetes and sedentary lifestyle. Recently, HDL transports small non-coding RNA molecule, called micro RNAs (miRNAs). Some miRNA are critical regulators of lipoprotein metabolism. The aim of this study was compare plasma lipids, lipid transfers to HDL, inflammatory profile, miRNAs related to plasma lipids from patients with HF with those from patients with without HF (non-HF). Methods: Forty-eight HF patients were studied, 25 with functional class NYHA I and II (HF I/II) and 23 with NYHA III and IV (HF III/IV), as well as 50 non-HF patients matched for gender, age and BMI. All HF had ejection fraction <= 40%. CETP, LCAT, oxidized LDL (oxLDL) and paraoxonase 1 (PON-1) activity were determined. Transfers of lipids from a donor artificial nanoparticle to HDL was determined by an in vitro assay in which the emulsion was incubated with whole plasma. Expression of circulating miRNAs involved in cholesterol metabolism was also analyzed. Results: Total, LDL and HDL cholesterol and triglycerides did not differ among the 3 groups. Apolipoprotein A-I was lower in NYHA I/II group compared to non- HF (125±23 versus 142±19; p < 0.05) and apo B was lower in NYHA III/IV group compared to non-HF (81±35 versus 114±40, p < 0.001). The transfer of esterified cholesterol (5.44±1.76 versus 6.26±0.85), phospholipids (19.05±2.5 versus 20.21±1.45) and of triglycerides (6.29±2.05 versus 7.40±1.47) to HDL was lower in HF-III/IV than in non-HF (p < 0.05), but lipid transfers were not different between HF-I/II and non-HF. oxLDL was lower in both HF groups compared to non-HF (p < 0.0001). CETP mass was lower in HF-III/IV than in HF-I/II (2.77±1.3 versus 3.78±1.3; p=0.021). LCAT and PON-1 activity was not different among the groups. Regarding to miRNA, miR-33a, miR-144, miR-185, miR-125, miR- 758, miR-26a, miR-106b, miR-122 e miR-30c were significantly increased in HF compared to non-HF subjects, whereas miR-10b was the only one found to be decreased in HF compared to non-HF subjects (p=0.007). Conclusion: In patients with the more severe and symptomatic HF, the lipid transfer to HDL is deficient, as well as some mechanisms that regulate it, and possibly these changes influence reverse cholesterol transport and the protective functions of HDL in these patients