Macrófagos (Mf) produzem PAF e PAF-R e eliminam partículas alteradas via CD36. Uptake de oxLDL requer associação CD36/PAF-R. Avaliamos isto na eferocitose. Bloqueio do PAF-R e de lipid rafts (LR) inibiu eferocitose. Esta induziu associação PAF-R/CD36 e destes com flotilina-1 (marca LR). Eferocitose induziu IL-10 e IL-12p40. Bloqueio do PAF-R inibiu mais IL-10 e inibição da COX-2 teve efeito similar, sugerindo que eferocitose depende da interação PAF-R/CD36 em LR e que isto induz prostanoides e perfil regulador. Mf adquirirem diferentes fenótipos. Estudamos a participação do PAF-R. Bloqueio do PAF-R antes dos estímulos (IFN-g/LPS, IL-4 ou IgG-SRBC/LPS) inibiu marcadores MCP-1, TNF-a, iNOS, receptor manose, arginase-1 e IL-10, mas não IL-12p40, sugerindo que PAF-R modula fenótipo de Mf. PAF e PAF-like são gerados por estressores oxidativos. Ativação do PAF-R induz imunossupressão sistêmica (IS). Mostramos que terapia fotodinâmica (PDT) in vitro gerou ligantes do PAF-R e in vivo inibiu reação de CHS em WT, mas não em PAF-R KO, sugerindo que PDT induz IS via PAF-R. / Macrophages (Mp) produce PAF and PAF-R and scavenge altered particles via CD36. oxLDL uptake requires association CD36/PAF-R. We analyzed that on efferocytosis. PAF-R and lipid rafts (LR) blockage inhibited efferocytosis. Efferocytosis induced association CD36/PAF-R and both with LR marker protein, and induced IL-10 and IL-12p40. PAF-R and COX-2 blockage inhibited more IL-10, suggesting that efferocytosis depends on PAF-R/CD36 interaction in LR and that this induces prostanoids and regulatory profile. Mp acquire different phenotypes. PAF-R participation in that was analyzed. PAF-R blockage before stimuli (IFN-g/LPS, IL-4 or IgG-SRBC/LPS) inhibited markers MCP-1, TNF-a, iNOS, mannose receptor, arginase-1 and IL-10, but not IL-12p40, suggesting that PAF-R modulates Mp phenotype. PAF and PAF-like are generated by oxidative stressors. PAF-R activation induces systemic immunosuppression (SI). We showed that photodynamic therapy (PDT) in vitro generated PAF-R ligands and in vivo inhibited CHS reaction in WT, but not PAF-R KO, suggesting that PDT induces SI via PAF-R.

A lipoproteína de baixa densidade (LDL) pode sofrer modificações, oxidativas ou enzimáticas, gerando compostos, lipídicos e proteicos, capazes de interagir com macrófagos, contribuindo para a resposta inflamatória presente na aterosclerose. Os macrófagos interagem tanto com LDL contendo baixo ou alto grau de oxidação (LoxLDL e HoxLDL) e também com fragmentos proteicos provenientes da ApoB-100, os quais podem exercer efeitos biológicos em macrófagos, contribuindo para a formação de células espumosas. Neste trabalho demonstramos que formas modificadas da LDL interagem com monócitos e/ou macrófagos, dependendo do grau de oxidação. A expressão de FcgRII por HoxLDL em macrófagos é dependente de PPARg. Parte da expressão de CD36 induzida por LoxLDL e HoxLDL em macrófagos é dependente de PAF-R. A LoxLDL induz uma maior produção de IL-6 e IL-8. Já, a HoxLDL de TNF-a, IL-10 e TGF-b em macrófagos. Encontramos um peptídeo da ApoB-100 é capaz de aumentar o fluxo intracelular de cálcio, ativar a via das MAP quinases em monócitos humanos, induzindo a produção de IL-8. / The Low Density Lipoprotein (LDL) may undergo oxidative or enzymatic modifications, producing lipid or proteic compounds that interact with macrophages, contributing to inflammatory response in the atherosclerosis. Into the arterial intima, the macrophages interact with minimally modified LDL (LoxLDL) and with highly oxidized LDL (HoxLDL). Moreover, in the arterial intima, enzymes may induce cleavage of the apoB-100, releasing protein fragments, which may have biological effects on macrophages. In this study, we showed that modified forms of LDL interact with monocytes or macrophages, depending on oxidation degree. The expression of FcgRII-induced HoxLDL in macrophages is dependent on PPARg and part of the expression of CD36 induced by LoxLDL and HoxLDL in macrophages is dependent on PAF-R. In macrophages, LoxLDL induced higher production of IL-6 e IL-8, whereas HoxLDL induced TNF-a, IL-10 e TGF-b. Furthermore, we found one peptide from apoB-100 capable to increase calcium flux and activate MAP kinase pathway, inducing production of IL-8 in human monocytes.

A lipoproteína de baixa densidade (LDL) pode sofrer modificações, oxidativas ou enzimáticas, gerando compostos, lipídicos e proteicos, capazes de interagir com macrófagos, contribuindo para a resposta inflamatória presente na aterosclerose. Os macrófagos interagem tanto com LDL contendo baixo ou alto grau de oxidação (LoxLDL e HoxLDL) e também com fragmentos proteicos provenientes da ApoB-100, os quais podem exercer efeitos biológicos em macrófagos, contribuindo para a formação de células espumosas. Neste trabalho demonstramos que formas modificadas da LDL interagem com monócitos e/ou macrófagos, dependendo do grau de oxidação. A expressão de FcgRII por HoxLDL em macrófagos é dependente de PPARg. Parte da expressão de CD36 induzida por LoxLDL e HoxLDL em macrófagos é dependente de PAF-R. A LoxLDL induz uma maior produção de IL-6 e IL-8. Já, a HoxLDL de TNF-a, IL-10 e TGF-b em macrófagos. Encontramos um peptídeo da ApoB-100 é capaz de aumentar o fluxo intracelular de cálcio, ativar a via das MAP quinases em monócitos humanos, induzindo a produção de IL-8. / The Low Density Lipoprotein (LDL) may undergo oxidative or enzymatic modifications, producing lipid or proteic compounds that interact with macrophages, contributing to inflammatory response in the atherosclerosis. Into the arterial intima, the macrophages interact with minimally modified LDL (LoxLDL) and with highly oxidized LDL (HoxLDL). Moreover, in the arterial intima, enzymes may induce cleavage of the apoB-100, releasing protein fragments, which may have biological effects on macrophages. In this study, we showed that modified forms of LDL interact with monocytes or macrophages, depending on oxidation degree. The expression of FcgRII-induced HoxLDL in macrophages is dependent on PPARg and part of the expression of CD36 induced by LoxLDL and HoxLDL in macrophages is dependent on PAF-R. In macrophages, LoxLDL induced higher production of IL-6 e IL-8, whereas HoxLDL induced TNF-a, IL-10 e TGF-b. Furthermore, we found one peptide from apoB-100 capable to increase calcium flux and activate MAP kinase pathway, inducing production of IL-8 in human monocytes.

Macrófagos (Mf) produzem PAF e PAF-R e eliminam partículas alteradas via CD36. Uptake de oxLDL requer associação CD36/PAF-R. Avaliamos isto na eferocitose. Bloqueio do PAF-R e de lipid rafts (LR) inibiu eferocitose. Esta induziu associação PAF-R/CD36 e destes com flotilina-1 (marca LR). Eferocitose induziu IL-10 e IL-12p40. Bloqueio do PAF-R inibiu mais IL-10 e inibição da COX-2 teve efeito similar, sugerindo que eferocitose depende da interação PAF-R/CD36 em LR e que isto induz prostanoides e perfil regulador. Mf adquirirem diferentes fenótipos. Estudamos a participação do PAF-R. Bloqueio do PAF-R antes dos estímulos (IFN-g/LPS, IL-4 ou IgG-SRBC/LPS) inibiu marcadores MCP-1, TNF-a, iNOS, receptor manose, arginase-1 e IL-10, mas não IL-12p40, sugerindo que PAF-R modula fenótipo de Mf. PAF e PAF-like são gerados por estressores oxidativos. Ativação do PAF-R induz imunossupressão sistêmica (IS). Mostramos que terapia fotodinâmica (PDT) in vitro gerou ligantes do PAF-R e in vivo inibiu reação de CHS em WT, mas não em PAF-R KO, sugerindo que PDT induz IS via PAF-R. / Macrophages (Mp) produce PAF and PAF-R and scavenge altered particles via CD36. oxLDL uptake requires association CD36/PAF-R. We analyzed that on efferocytosis. PAF-R and lipid rafts (LR) blockage inhibited efferocytosis. Efferocytosis induced association CD36/PAF-R and both with LR marker protein, and induced IL-10 and IL-12p40. PAF-R and COX-2 blockage inhibited more IL-10, suggesting that efferocytosis depends on PAF-R/CD36 interaction in LR and that this induces prostanoids and regulatory profile. Mp acquire different phenotypes. PAF-R participation in that was analyzed. PAF-R blockage before stimuli (IFN-g/LPS, IL-4 or IgG-SRBC/LPS) inhibited markers MCP-1, TNF-a, iNOS, mannose receptor, arginase-1 and IL-10, but not IL-12p40, suggesting that PAF-R modulates Mp phenotype. PAF and PAF-like are generated by oxidative stressors. PAF-R activation induces systemic immunosuppression (SI). We showed that photodynamic therapy (PDT) in vitro generated PAF-R ligands and in vivo inhibited CHS reaction in WT, but not PAF-R KO, suggesting that PDT induces SI via PAF-R.

No description available.

Les prodrogues sont des dérivés biologiquement inactifs d’un principe actif qui, après administration à un organisme, subissent une transformation chimique ou enzymatique pour libérer le principe actif au site d’action. Elles améliorent les propriétés physicochimiques du principe actif pour permettre un meilleur transport à travers les barrières biologiques et pour augmenter l’activité in vivo. Elles sont utilisées pour améliorer la formulation et l’administration, accroître la perméabilité et l’absorption, modifier le profil de distribution et éviter le métabolisme et la toxicité. Cette approche est très utile pour améliorer l'administration de principes actifs. Il existe deux types de prodrogues : les prodrogues liées à un transporteur et les bioprécurseurs. Dans le premier cas, la molécule active est liée par une liaison covalente à un groupement temporaire, ce qui fournit une nouvelle molécule, qui est inactive. Le groupement temporaire libéré ne doit pas avoir, par lui-même, d'action pharmacologique ni de toxicité. Dans le second cas, le principe actif est transformé métaboliquement ou chimiquement par réaction d’hydratation, d’oxydation ou de réduction. Les azapeptides sont des mimes peptidiques dans lesquels un ou plusieurs carbones de la chaîne peptidique sont remplacés par des atomes d’azote. Ce remplacement augmente la rigidité de la chaîne peptidique et favorise le repliement de type β. Le repliement β des azapeptides est associé à plusieurs propriétés thérapeutiques. Certains azapeptides ont montré une meilleure activité, une meilleure sélectivité et une plus grande stabilité comparativement aux peptides parents ce qui prolonge leur durée d'action et les rend plus résistants aux dégradations métaboliques. Ce mémoire s’intéresse particulièrement à l’azapeptide : [aza(p-MeO)F⁴]-GHRP-6. Celui-ci est un analogue du peptide sécréteur d’hormone de croissance 6 (GHRP-6, H-His-D-Trp-Ala-Trp-D-Phe-Lys-NH₂), qui possède une affinité pour deux récepteurs distincts : les récepteurs de growth hormone secretagogue receptor 1a (GHS-R1a) et le récepteur cluster of differentiation 36 (CD36). L’[aza(p-MeO)F⁴]-GHRP-6 démontre une sélectivité envers le récepteur CD36 offrant des possibilités de traitement de maladies telles que l’athérosclérose et la dégénérescence maculaire liée à l’âge (DMLA). De plus, le récepteur CD36 peut interagir avec un corécepteur toll-like receptor 2 (TLR2), et l’[aza(p-MeO)F⁴]-GHRP-6 peut réduire des réponses immunitaires innées. La stratégie des prodrogues a été utilisée dans ce mémoire pour augmenter la durée d’action de l’azapeptide [aza(p-MeO)F⁴]-GHRP-6. Plus précisément, cinq analogues des prodrogues α-acyloxyéthylcarbamates de l’aza(p-MeO)F⁴-GHRP-6 ont été synthétisées. Ce mémoire présente la première synthèse de prodrogues α-acyloxyéthylcarbamates à caractère PEG de l’[aza(p-MeO)F⁴]-GHRP-6. / A prodrug is a biologically inactive derivative of a drug which after administration undergoes chemical or enzymatic modification to release the active drug at targeted sites of activity. Prodrugs improve physicochemical properties to enable better transport through biological barriers and enhance activity. They are used to improve formulation and administration, to enhance permeability and absorption, to modify distribution profiles and to avoid metabolism and toxicity. The prodrug approach is useful for improving drug delivery. Prodrugs are classified into two types: carrier-linked prodrugs and bio-precursors. In the first case, the parent drug is linked by a covalent bond to an inert carrier or transport moiety. The carrier should not be active or toxic. The active drug is released by a chemical or enzymatic cleavage in vivo. In the second case, the parent drug is converted metabolically or chemically by hydration, oxidation or reduction reactions. Azapeptides employ a semicarbazide as an amino amide surrogate in a peptide analog in which the backbone α-CH is replaced by nitrogen. Through electronic interactions, the semicarbazide favors backbone β-turn geometry due to a combination of urea planarity and hydrazine nitrogen lone pair – lone pair repulsion. Azapeptides have proven therapeutic utility. Some of them exhibit better selectivity, activity and stability than the parent peptides with increased duration of action and improved metabolic stability. Growth hormone releasing peptide-6 (GHRP-6, H-His-D-Trp-Ala-Trp-D-Phe-Lys-NH₂) is a synthetic peptide possessing an affinity for two different receptors: growth hormone secretagogue receptor 1a (GHS-R1a) and cluster of differentiation receptor 36 (CD36). The GHRP-6 azapeptide analogue, [aza(p-MeO)F⁴]-GHRP-6, has exhibited good affinity for CD36 and reduced nitric oxide overproduction in macrophage cells stimulated with the TLR-2 agonist R-FSL-1. Azapeptide ligands of CD36, such as [aza(p-MeO)F⁴]-GHRP-6, offers potential as prototypes for developing treatments of diseases such as atherosclerosis and age-related macular degeneration. A prodrug strategy has been pursued to improve the pharmacokinetic properties, such as duration of action, of [aza(p-MeO)F⁴]-GHRP-6. The first examples of α-acyloxyethyl carbamate peptides have been prepared. Five α-acyloxyethyl carbamate analogues of [aza(p-MeO)F⁴]-GHRP-6 have been synthesized by routes featuring acylation of the resin-bound peptide using different activated α-acyloxyethyl carbonates prior to resin cleavage and side chain deprotection. The evaluation of the activity of the pharmacokinetic properties of the [aza(p-MeO)F⁴]-GHRP-6 prodrugs is currently in progress and will be reported in due time.