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L’anémie est un symptôme fréquent chez les patients atteints de cancer. La libération de la cytokine pro-inflammatoire TNFα, un inhibiteur connu de l’érythropoïèse, en est l’une des causes. L’érythropoïèse est un processus nécessitant l’arrêt de la prolifération et l’autophagie. Les résultats précédents ont montré que le TNFα inhibe l’expression des marqueurs érythroïdes et module l’expression de facteurs de transcription (FT) hématopoïétiques. Notre objectif est d’étudier l’implication de la voie TNFα/sphingomyélinase (SMase)/céramide dans l’inhibition de l’érythropoïèse en utilisant des cellules souches hématopoïétiques CD34+ induites à se différencier par l’érythropoïétine recombinante (Epo). Par l’utilisation de céramides exogènes, de SMase bactérienne et d’inhibiteurs de SMases, nous montrons l’implication de la voie SMase/céramide dans l’inhibition de l’expression des marqueurs érythroïdes mais également dans l’induction de la différenciation myéloïde avec une augmentation de l’expression du CD11b. Cet effet sur la différenciation est corrélé à la modulation du réseau FT/miR impliquant GATA-1, GATA-2 et PU.1 et les miR-144, 451, 155, 146a et 223. De plus, l’analyse par microscopie électronique à transmission, l’absence de formation de punctae GFP-LC3 et l’accumulation de SQSTM1/p62 montrent que le TNFα et les céramides inhibent l’autophagie induite par l’Epo. L’analyse des protéines impliquées dans la régulation de l’autophagie montre que le TNFα et les céramides activent mTOR. Son implication est confirmée par l’utilisation de rapamycine et l’inhibition de ULK1 et Atg13. De plus, le TNFα et les céramides inhibent l’expression de bécline 1 et de la formation du complexe Atg5-Atg12. Ces résultats démontrent que la voie TNFα/SMase/céramide joue un rôle dans l’homéostasie hématopoïétique par l’inhibition de l’érythropoïèse au profit de la myélopoïèse, en impactant les réseaux de régulation FT/miR et le processus d’autophagie / Anemia is a common symptom in cancer patients. It can be caused by the release of pro-inflammatory cytokines such as TNFα, a known inhibitor of erythropoiesis. Erythropoiesis involves proliferation arrest and autophagy. Our previous studies showed that TNFα inhibits the expression of erythroid markers as well as hematopoietic transcription factors (TF) expression. The aim is to study the involvement of TNFα/sphingomyelinase (SMase)/ceramide pathway in erythropoiesis inhibition using recombinant erythropoietin (Epo)-induced CD34+ hematopoietic stem cells. Using exogenous ceramides, a bacterial SMase and sphingomyelinase inhibitors, we show the involvement of SMase/ceramide pathway in the inhibition of erythroid markers as well as the induction of myeloid differentiation as shown by the increase in CD11b expression. This effect is correlated to the modulation of the TF/miR network involving GATA-1, GATA-2 and PU.1 as well as miR-144, 451, 155, 146a and 223. We show that TNFα and ceramides inhibit Epo-induced autophagy through transmission electron microscopy analysis, the absence of GFP-LC3 punctae formation and SQSTM1/p62 accumulation. Analysis of proteins involved in autophagy regulation showed that TNFα and ceramides activate mTOR, which is confirmed using rapamycin as well as the inhibition of ULK1 and Atg13. Moreover, TNFα and ceramides inhibit Beclin 1 expression and Atg5-Atg12 complex formation. These results demonstrate the role of TNFα/SMase/ceramide pathway in hematopoietic homeostasis through an erythropoiesis-myelopoiesis switch resulting from perturbation of TF/miR network and autophagy

Placental dysfunction is implicated in the pathogenesis of preeclampsia. Chemical signals between the placenta and maternal circulation are a suspect cause of endothelial dysfunction and maternal hypertension. This study examined select lipid mediators of inflammation produced by the placenta. Patients were recruited from Virginia Commonwealth University’s pregnancy clinics and placentas were collected at delivery. Forty-eight-hour explant cultures of villous placental tissue were used to model lipid production. Electrospray ionization mass spectrometry was used to quantify concentrations of free lipids in the culture media. Bicinchoninic acid assays were performed to quantify protein in each culture for normalization of lipid data. After analysis, it was found that severity of preeclampsia was correlated with a unique lipid profile. Pro-inflammatory hydroxyeicosatetraenoic acids and sphingolipids were elevated. Aspirin usage in patients who developed preeclampsia was found to attenuate accumulation of isoprostane oxidative stress markers and thromboxane production while preserving omega-3-fatty acid and increasing prostacyclin levels.

Thesis (Ph. D.)--Oregon State University, 2009. / Printout. Includes bibliographical references. Also available on the World Wide Web.

Background & Aims: The 'high-density lipoprotein (HDL) hypothesis', that therapeutic interventions directed at raising HDL cholesterol might translate into improved cardiovascular outcomes, has been confounded by recent reports from genetic and pharmacological studies. HDL functionality may be more important than cholesterol cargo. HDL cholesterol levels are normal or even high in Type 1 Diabetes (T1DM) but do not seem to protect against atherosclerosis as might be expected; this thesis aims to offer new insight into HDL functionality through examination of these patients. This thesis also aims to improve understanding of the qualitative changes in lipoproteins associated with diabetes and increased cardiovascular morbidity, with emphasis on atherogenic modifications of apolipoprotein B and sphingolipids, and consideration of the relationship between these changes, novel and established biomarkers, and macrovascular and microvascular diabetic complications. Materials & Methods: Patients with Type 1 (n = 91) and Type 2 (n = 40) Diabetes Mellitus and healthy volunteers (n = 104) attended for fasting blood tests, urinalysis, and examination including cardiac computed tomography, carotid doppler studies and assessments of nerve function. In vitro studies of lipoprotein modification used pooled human plasma. Results: Lipoprotein glycation represents an atherogenic modification. In vitro glycation occurs more readily in the presence of physiological concentrations of copper. HDL and copper-selective chelation with triethylenetetramine prevents glycation. Glycated apolipoprotein B, oxidized LDL and small-dense LDL levels were significantly higher in T1DM; HDL cholesterol levels were also significantly higher, but with altered apolipoprotein distribution, and significantly lower cholesterol efflux capacity and PON1 activity than in healthy controls. Significant changes were also observed in cystatin C, advanced glycation end-products, leucine-rich alpha-2-glycoprotein, lipoprotein-associated phospholipase A2, a variety of inflammatory markers, and sphingolipid and ceramide profiles. Discussion: Cardiovascular disease is the leading cause of death and disability in diabetes. Patients with diabetes show qualitative and kinetic lipoprotein abnormalities, and any cardiovascular benefit associated with intensive glucose lowering may be related to effects on lipoprotein metabolism rather than directly through altered glycaemia. The apparently relatively undisturbed lipid profile observed in many patients with diabetes hides major atherogenic changes and altered HDL functionality, which may be at least partially responsible for the persistent increased risk of cardiovascular disease in patients with diabetes. HDL-based therapy remains a largely unfulfilled promise, but there may be a role for copper-selective chelation and more aggressive low-density lipoprotein lowering in the reduction of diabetic complications.

Orientador: Luiz Carlos Dias / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-10T02:46:17Z (GMT). No. of bitstreams: 1 Fattori_Juliana_M.pdf: 2240885 bytes, checksum: 9db38d985e4bc4fb6668aeb311352757 (MD5) Previous issue date: 2007 / Resumo: A unidade aminodiol está presente em esfingolipídeos que são uma importante classe de biomoléculas. Os esfingolipídeos são componentes das membranas celulares e estão relacionados a processos de crescimento, diferenciação celular e apoptose. Alguns esfingolipídeos como a esfingosina e compostos análogos apresentam atividade antitumoral, por isso metodologias para a obtenção de compostos deste tipo têm despertado a atenção dos químicos orgânicos sintéticos. Assim, neste trabalho foi desenvolvida uma metodologia curta e eficiente para a preparacao de derivados de 2-amino-3,5-diois, com o intuito de fornecer material para testes biologicos. A sintese aqui apresentada envolveu o acoplamento de uma aliltricloroestanana aquiral com a-aminoaldeidos fornecendo alcoois homoalilicos em bons rendimentos e com alta diastereosseletividade. Em seguida a clivagem oxidativa da dupla ligação presente nos álcoois homoalilicos levou a formacao de b-hidroxicetonas inéditas na literatura. E, por fim, a reducao das b-hidroxicetonas sob diferentes condições conduziu aos 2-amino-3,5-diois 1,3-syn e 1,3-anti em bons rendimentos e excelente diastereosseletividade / Abstract: The aminodiol moiety is present in sphingolipids which are an important class of biologically active compounds. These compounds play an important role in the chemistry of cellular membranes, cell growth differentiation and apoptosis. Some of them, like sphingosine and analogues have showed anticancer activity. Therefore procedures to prepare this kind of compounds have been developed by the organic chemists. In this work we have developed a short and efficient route for the synthesis of 2- amino-3,5-diol derivatives, in order to provide material for further biological studies. Our approach to the 2-amino-3,5-diols involved the coupling of an achiral alilthriclorostannane with a-aminoaldehydes to give the corresponding homoallylic alcohols in good yields and with high levels of diastereoslectivity. Double bond oxidation gave the corresponding b-hydroxyketones in excellent yields. Finally, reduction of the b-hydroxyketones under different conditions gave the desired 2- amino-3,5-diols 1,3-syn and 1,3-anti in good yields and high diastereoselectivities / Mestrado / Quimica Organica / Mestre em Química

Orientador: Luiz Carlos Dias / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-11T02:21:07Z (GMT). No. of bitstreams: 1 Perez_CarlaCristina_M.pdf: 3422418 bytes, checksum: ae937d7829a969d84f9544e0e41a8aa3 (MD5) Previous issue date: 2008 / Resumo: Neste trabalho descrevemos a reação diastereosseletiva entre aldeidos quirais N-Boc-a-aminoaldeídos e uma aliltricloroestanana aquiral fornecendo 1,2-syn N-Boc-aminoálcoois em altas diastereosseletividades. A estereoquímica relativa 1,2-syn dos produtos de adição foi determinada após conversão dos alcoóis homoalílicos nas correspondentes N-Boc-oxazolidinonas seguido pela analise das constantes de acoplamento no espectro de RMN de H. O tratamento dos alcoóis homoalílicos com quantidade catalítica de OsO4 na presença de NaIO4 forneceu as correspondentes 4-N-Boc-amino-3-hidroxicetonas. É importante ressaltar que não havia metodologias na literatura descrevendo a obtenção de 4-N-Boc-amino-3-hidroxicetonas, sendo este um método eficiente para obtenção dessa classe de compostos. A redução diastereosseletiva das 4-N-Boc-amino-3,5-hidroxicetonas forneceu os aminodióis 1,3-syn e 1,3-anti, respectivamente. A estereoquímica relativa 1,3 foi determinada após a conversão dos aminodióis nos correspondentes isopropilideno acetais e posterior análise de RMN de C / Abstract: We wish to describe here the diastereoselective reaction between chiral N-Boc-a-amino aldehydes and achiral allyltrichlorostannanes leading to 1,2-syn-N-Boc-a-amino alcohols in high diastereoselectivies. The 1,2-syn relative stereochemistry was determined after conversion of homoallylic alcohols to the corresponding N-Boc-oxazolidinones followed by analyses of the coupling constants in the H NMR spectra. Treatment of the homoallylic alcohols with catalytic amounts of OsO4 in the presence of NaIO4 provided the corresponding 4-N-Boc-amino-3-hydroxy ketones. It is very important to point out that, to the best of our knowledge, there was no useful and general approach to 4-N-Boc-amino-3-hydroxy ketones described in the literarure and this methodology stands as the most efficient approach to this class of compounds. Diastereoselective reduction of the 4-N-Boc-amino-3-hydroxy ketones provided the 1,3-syn and 1,3-anti aminodiols, respectively. The 1,3 relative stereochemistry was determined after C-NMR analyses of the corresponding isopropylidene acetals / Mestrado / Quimica Organica / Mestre em Química

Title of the Master thesis: Synthesis and evaluation of human 6-hydroxyceramides Candidate: Adam Majcher Supervisor: PharmDr. Lukáš Opálka, Ph.D. Consultant: PharmDr. Andrej Kováčik, Ph.D. Charles University, Faculty of Pharmacy in Hradec Králové Skin Barrier Research Group, Department of Organic and Bioorganic Chemistry Ceramides (Cer), the members of sphingolipid family, occur in all human cells and play an important role in cell signaling. In high concentrations, Cer can also be found in the uppermost layer of epidermis called stratum corneum, along with free fatty acids and cholesterol (in equimolar ratio), where they form the intercellular multi-lamellar lipid matrix. The key function of stratum corneum is to ensure a permeability barrier, thus, to provide water and electrolyte homeostasis, and to prevent entry of harmful substances into the organism. Cer are composed of a sphingoid base and an acyl part derived from a long-chain fatty acid. Cer based on 6-hydroxysphingosine (H) are amongst the most unusual sphingolipids. In contrast to sphingosine-based Cer, 6-hydroxysphingosine-based Cer (H-Cer) are unique for the epidermis and, in addition, H-Cer are not typical for all mammals. Moreover, the function and biosynthesis of H-Cer in the skin is still not completely understood. Several...

Charles University Faculty of Pharmacy in Hradec Králové Department of pharmeceutical technology Candidate: Oksana Yanok Supervisor: Pharm.Dr. Andrej Kováčik, Ph.D. Title of Diploma Thesis: The effects of glucosyl sphingosine on barrier function of skin and complex skin model. The skin barrier, which provides protection from water loss and harmful environmental influences is located in the stratum corneum. The dominant group of lipids within the stratum corneum are ceramides (Cer), which also have the most important role in ensuring the barrier properties of the skin. The enzymes sphingomyelin deacylase and glucosylceramide deacylase hydrolyze the amide bond of Cer precursors, which leads to highly polar metabolites, called lysolipids. The increased activity of these enzymes is considered to be one of the major factors leading to the development of a number of skin diseases characterized by a skin barrier disorder (for example atopic dermatitis). In this study we prepared model membranes mimicking a healthy skin barrier as an equimolar mixtures of human Cer, cholesterol, free fatty acids with the addition of 5 % cholesterol sulfate. We also prepared models in which the amount of Cer was gradually reduced and replaced by the hydrophilic lysolipid glucosylsphingosine. The permeability was measured...

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