Thrombospondin-1 (TSP-1) binding to its membrane receptor CD47 results in an inhibtion of the nitric oxide (NO) receptor soluble guanylate cyclase (sGC) and a decrease in intracellular cGMP levels. This causes physiologic effects such as vasoconstriction and a rise in blood pressure. The mechanism by which TSP-1 binds to CD47 at the membrane to decrease sGC activity is largely unknown. CD47 can physically associate with a number of binding partners, including α(v)β₃ and vascular endothelial growth factor receptor 2 (VEGFR2). Binding of a C-terminal fragment of TSP-1 called E3CaG1 to CD47 leads to a rise in intracellular calcium ([Ca²⁺](i)), which decreases sGC activity via a phosphorylation event. Binding of E3CaG1 is also known to disrupt the interaction between CD47 and VEGFR2, leading to a decrease in endothelial nitric-oxide synthase (eNOS) activity and cGMP levels through an Akt signaling pathway. However, it is not known whether other membrane proteins associated with CD47 are required for E3CaG1 binding and a subsequent [Ca²⁺](i) increase. Plasmon-waveguide resonance (PWR) spectroscopy was employed to elucidate the mechanism of TSP-1 inhibition of sGC activity through membrane complexes involving CD47. Using PWR, I found E3CaG1 can bind specifically to CD47 within native Jurkat membranes with picomolar and nanomolar dissociation constants (K(d)), suggesting multiple CD47 complexes are present. Among these complexes, CD47/VEGFR2 was found to bind E3CaG1 with a picomolar K(d)and CD47/α(v)β₃ was found to bind E3CaG1 with a nanomolar K(d). In addition, the presence of an anti-VEGFR2 antibody inhibited the E3CaG1-induced calcium response, which suggested CD47 in complex with VEGFR2 was responsible for TSP-1 reduction of sGC activity. I show that when both CD47 and VEGFR2 are returned to a HEK 293T cell line that does not contain these receptors, an increase in [Ca²⁺](i) upon E3CaG1 binding is restored. Interestingly, E3CaG1 was also found to bind to VEGFR2 in complex with the integrin α(v)β₃ on CD47-null cell lines and their derivations, causing a decrease in [Ca²⁺](i) levels. Therefore, the third type 2 repeat and C-terminal domains of TSP-1 can cause both increases and decreases in calcium based upon the availability of protein complexes to which it binds.

<p>The Immunity-Related GTPases (IRGs) are a family of dynamin-like proteins found in vertebrates that play critical roles in cell-autonomous resistance to bacteria and protozoa. The IRGs are divided into two subfamilies, with the GMS IRGs exerting a regulatory function over the GKS IRGs, affecting GKS IRG expression, localization, and ultimately function. The profound loss of host resistance seen in mice lacking the GMS protein Irgm1 suggests that GMS IRGs may additionally have broader functions beyond the regulation of GKS IRGs, though the nature of these functions remains poorly understood. In this dissertation, we address the regulatory functions of GMS IRGs in mouse cells.</p><p>We first addressed regulation of GKS IRGs (Irga6 and Irgb6) by GMS IRGs (Irgm1 and Irgm3). We found that in both fibroblasts and macrophages lacking these GMS IRGs, that the GKS IRGs relocalized to form punctate structures that were ubiquitin-, p62-, and LC3-positive. A biochemical analysis indicated that the GKS IRGs were directly ubiquitinated through K63 linkages. Collectively, these results suggested that GMS IRGs regulate aggregation of GKS IRGs and their transfer to autophagosomes through one of at least two possible mechanisms -- by the direct association of GMS IRGs with GKS IRGs to block their aggregation that subsequently leads to autophagic removal, and/or by directly promoting autophagic removal of spontaneously forming GKS aggregates. The latter hypothesis was addressed using a series of complementary assays, which ultimately showed that absence of Irgm1 has no effect on the maturation of autophagosomes in fibroblasts, and only a very small and statistically insignificant effect in macrophages. Thus, we conclude that the major mechanism through which GMS IRGs regulate GKS IRGs is by directly inhibiting their aggregation, rather than through general effects on autophagic initiation or maturation of GKS IRG-containing autophagosomes.</p><p>We also addressed the possibility of broad regulatory functions of GMS IRGs beyond the regulation of GKS IRGs by examining whether GMS IRGs can affect another family of dynamin-like GTPases, the guanylate-binding proteins (GBPs). Despite no previous evidence of interactions between these two protein families, we found that the absence of GMS IRGs had striking effects on the localization of the murine Gbp2, leading it to colocalize with GKS IRG aggregates formed as a consequence of GMS IRG deficiency. We further demonstrated that unlike the GKS IRGs, Gbp2 was not tagged with K63-linked ubiquitin chains, which might have targeted it for specific macroautophagy, implying that Gbp2 is not aggregating in the absence of Irgm1. We then showed both that Gbp2 forms puncta in the presence of generic protein aggregates, and that guanylate-binding proteins including Gbp2 promote the degradation of GKS IRG protein aggregates. These findings suggest that GMS IRGs do not exert direct control over GBPs, but rather that GBPs are involved in the macroautophagic degradation of protein aggregates as a primary function, and are thus influenced indirectly by GMS IRGs.</p><p>In total, our experiments contribute to the understanding of regulatory interactions among GMS IRGs, GKS IRGs, and GBPs. These results will be important in establishing the mechanisms through which these important families of proteins influence eradication of bacterial and protozoan pathogens through key innate immune mechanisms.</p> / Dissertation

Thesis (Ph. D.)--University of Washington, 1999. / Vita. Includes bibliographical references (leaves [106]-128).

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / Previamente, foi demonstrado que o tratamento via intravenosa com 1-nitro-2-feniletano (NFE) induziu hipotensÃo que resulta principalmente de sua aÃÃo vasodilatadora diretamente sobre o mÃsculo liso. Nesse estudo, estudamos o mecanismo subjacente ao efeito miorrelaxante do NFE em tecidos vasculares isolados de ratos. Registros isomÃtricos foram obtidos a partir de anÃis isolados de artÃria aorta e do segundo ramo da mesentÃrica de ratos atravÃs de sistema de aquisiÃÃo de dados. Experimentos in silico (docking) de simulaÃÃo da formaÃÃo de complexos entre o NFE e a enzima guanilato ciclase foram realizados. Em preparaÃÃes de aorta isolada com endotÃlio intacto, NFE (1-300 &#61549;g/mL) relaxou a contraÃÃo induzida por fenilefrina ou K+, com valores de CI50 de 35,0 [23,3â52,6] e 73,2 [39,5â134,3] &#61549;g/mL, respectivamente. Os efeitos vasorrelaxantes do NFE foram significativamente (P < 0,05, teste de Mann-Whitney) reduzidos pelo tratamento prÃvio com ODQ (10 ÂM), azul de metileno (10 ÂM), TEA (5 mM), glibenclamida (10 ÂM) ou 4-aminopiridina (1 mM), mas nÃo pela remoÃÃo do endotÃlio vascular ou pelo prÃ-tratamento com L-NAME (100 &#956;M), indometacina (10 &#956;M), MDL-12.330A (3 &#956;M), KT5823 (0.5 ÂM) ou KT5720 (1 &#956;M). A potÃncia do NFE para induzir efeito vasorrelaxante foi significantemente maior (p < 0,01, teste de Mann-Whitney) nas preparaÃÃes de artÃria mesentÃrica quando comparado à aorta, tanto nas contraÃÃes induzidas por K+ como por noradrenalina com valores de CI50 de 5,3 [2,6â10,5] e 6,5 [2,8â14,9] Âg/mL, respectivamente. Em um meio sem cÃlcio, na presenÃa de K+ 60 mM ou fenilefrina 1 ÂM, as contraÃÃes induzidas CaCl2 foram significativamente reduzidas e atà mesmo abolidas pelo NFE na concentraÃÃo de 100 Âg/mL, respectivamente. Em meio sem cÃlcio, contendo EGTA, a resposta contrÃtil da fenilefrina foi significantemente reduzida pelo NFE (100 Âg/mL ), efeito impedido pelo tratamento com ODQ (10 ÂM), enquanto nÃo teve efeito significativo sobre as contraÃÃes induzidas por cafeÃna. Resultados semelhantes foram obtidos com nitroprussiato de sÃdio. NFE tambÃm foi capaz de inibir a contraÃÃo induzida pela entrada capacitativa de cÃlcio e pelo Ãster de forbol. AlÃm disso, os resultados de docking revelam que existem clusters de provÃveis interaÃÃes do NFE com a enzima guanilato ciclase. O presente estudo sugere que a atividade vasorrelaxante do NFE em aorta de rato à causada por provÃvel estimulaÃÃo da guanilato ciclase e consequente ativaÃÃo da cascata enzimÃtica guanilato ciclase/GMPc/canais de K+. / It was early shown that intravenous treatment with 1-nitro-2-phenylethane (NPE) induced hypotension resulting mainly from its direct vasodilatory action on vascular smooth muscle. Here, it was sudied the underlying mechanism involved in the vasorelaxant effect of NPE in isolated rings of rat arteries. Isometric recordings were obtained from rings made from aorta or mesenteric artery using a digital acquisition system. Experiments in silico (docking) for simulation of molecular interactions between NPE and the enzyme guanylate cyclase were performed. In endothelium-intact aortic preparations, NPE (1-300 &#61549;g/mL) relaxed the phenylephrine or K+-induced contractions with IC50 values of 35.0 [23.3- 52.6] and 73.2 [39.5-134.3] &#61549;g/mL, respectively. Vasorelaxant effects of NPE were significantly (P <0.05, Mann-Whitney test) decreased by pretreatment with ODQ (10 ÂM), methylene blue (10 ÂM), TEA (5 mM), glibenclamide (10 ÂM) or 4-aminopyridine (1 mM) but not by vascular endothelium removal or by pretreatment with L-NAME (100 ÂM), indomethacin (10 ÂM), MDL-12.330A (3 ÂM), KT5823 (0.5 ÂM ) or KT5720 (1 ÂM). Pharmacological potency of NPE was significantly greater (p <0.01, Mann-Whitney test) in preparations of mesenteric artery compared to that of aorta, as in K+- and norepinephrine-induced contraction with IC50 values of 5.3 [2.6-10.5] and 6.5 [2.8-14.9] &#61549;g/mL, respectively. In calcium-free medium, in presence of K+ 60 mM or phenylephrine 1 &#956;M, the CaCl2-induced contractions were significantly reduced and almost abolished by NPE at 100 &#956;g/mL, respectively. In calcium-free medium, containing EGTA, the contractile response of phenylephrine was significantly reduced by NPE (100 &#61549;g/mL), an effect prevented by treatment with ODQ (10 ÂM), whereas NPE was deprived of any significant effect on caffeine-induced contractions. Similar results were obtained with sodium nitroprusside. NPE also inhibited the contractions induced by the capacitive calcium entry or by phorbol ester. In addition, docking results revealed clusters of interactions of NPE with the guanylate cyclase molecule. The present study suggests that vasorelaxant activity of NPE on rat aorta is due to its stimulatory properties on guanylate cyclase, which activates the guanylate cyclase/cGMP/K+ channels pathway.

Orientador: Edson Antunes / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-22T00:44:09Z (GMT). No. of bitstreams: 1 Silverio_CamilaBitencourtMendes_M.pdf: 1655028 bytes, checksum: e42d500e98127c5551d4f94269778bcd (MD5) Previous issue date: 2013 / Resumo: O BAY 60-2770 constitui-se um novo ativador da guanilil ciclase solúvel (GCs) independente de óxido nítrico (NO). Há relatos de que ativadores da GCs independente de NO podem reativar esta enzima, mesmo em seu estado heme-oxidada, condição encontrada em doenças vasculares. Neste trabalho, temos por hipótese que a oxidação do grupamento heme da GCs pelo ODQ leva à potencialização dos efeitos antiplaquetários in vitro do BAY 60-2770. Foram utilizadas plaquetas humanas purificadas de voluntários sadios. Realizamos ensaios de agregação e de adesão plaquetária, bem como análise da ativação da integrina plaquetária, ?IIb?3, por citometria de fluxo. Realizamos Também ensaios de Western blotting para a quantificação protéica das subunidades ?1 e ?1 da GCs. Os níveis intracelulares de Ca2+ foram quantificados por fluorimetria, utilizando-se o fluoróforo FluoFort. O BAY 60-2770 (0,001 - 10 ?M) produziu inibição significativa da agregação plaquetária induzida pelo colágeno (2 ?g/mL) ou trombina (0,1 U/mL), sendo este efeito marcantemente potencializado pelo inibidor da GCs, ODQ (10 ?M). Em placas recobertas pelo fibrinogênio, o BAY 60-2770 (0,1 - 10 ?M) inibiu significativamente a adesão plaquetária, sendo esta inibição também potencializada pelo ODQ (10 ?M). O BAY 60-2770 (0,01 - 10 ?M) aumentou os níveis de GMPc e reduziu a mobilização de Ca2+, e ambos os efeitos foram potencializados pelo ODQ. O análogo permeável do GMPc, 8-Bromo-GMPc (8-Br-GMPc; 100 ?M), inibiu a agregação plaquetária e os níveis de Ca2+ de maneira ODQ-resistente. Os níveis de AMPc não foram alterados pelo BAY 60-2770. O colágeno (2 ?g/mL) e trombina (0,1 U/mL) ativaram a integrina ?IIb?3. Este efeito foi inibido pelo BAY 60-2770 (0,01 - 10 ?M), e potencializado pelo ODQ. Os efeitos antiplaquetários do nitroprussiato de sódio (SNP) foram totalmente revertidos pelo ODQ. O tratamento com ODQ (10 ?M) reduziu significativamente os níveis protéicos das subunidades ?1 e ?1 da GCs, os quais foram prevenidos pelo tratamento com BAY 60-2770. Os efeitos inibitórios do BAY 60-2770 sobre a agregação e adesão plaquetária, mobilização intracelular de Ca2+ e ativação da integrina ?IIb?3 foram todos potencializados em condições de heme-oxidação. O BAY 60-2770 impediu a diminuição dos níveis protéicos da GCs produzida por ODQ. Assim, o BAY 60-2770 pode ser de grande interesse terapêutico em doenças cardiovasculares associadas às complicações tromboembólicas / Abstract: Nitric oxide-independent soluble guanylyl cyclase (sGC) activators reactivate the haem-oxidized enzyme in vascular diseases. This study was undertaken to investigate the anti-platelet mechanisms of the haem-independent sGC activator BAY 60-2770 in human washed platelets. The hypothesis that sGC oxidation potentiates the anti-platelet activities of BAY 60-2770 has been tested. Human washed platelet aggregation and adhesion assays, as well as flow cytometry for ?IIb?3 integrin activation and Western blot for ?1 and ?1 sGC subunits were performed. Intracellular calcium levels were monitored in platelets loaded with a fluorogenic calcium-binding dye (FluoForte). BAY 60-2770 (0.001-10 ?M) produced significant inhibition of collagen (2 ?g/ml)- and thrombin (0.1 U/ml)-induced platelet aggregation that was markedly potentiated by the sGC inhibitor ODQ (10 ?M). In fibrinogen-coated plates, BAY 60-2770 (0.1 - 10 ?M) significantly inhibited platelet adhesion, an effect potentiated by ODQ. BAY 60-2770 (0.01 - 10 ?M) increased the cGMP levels and reduced the intracellular Ca2+ levels, both of which were potentiated by ODQ. The cell-permeable cGMP analogue 8-Br-cGMP (100 ?M) inhibited platelet aggregation and Ca2+ levels in an ODQ-insensitive manner. The cAMP levels remained unchanged by BAY 60-2770. Collagen- and thrombin-induced ?IIb?3 activation was markedly inhibited by BAY 60-2770 that was further inhibited by ODQ. The effects of sodium nitroprusside (3 ?M) were all prevented by ODQ. Incubation with ODQ (10 ?M) significantly reduced the protein levels of ?1 and ?1 sGC subunits, which were prevented by BAY 60-2770. The inhibitory effects of BAY 60-2770 on aggregation, adhesion, intracellular Ca2+ levels and ?IIb?3 activation are all potentiated in haem-oxidizing conditions. BAY 60-2770 prevents ODQ-induced decrease in sGC protein levels. BAY 60-2770 could be of therapeutic interest in cardiovascular diseases associated with thrombotic complications / Mestrado / Farmacologia / Mestra em Farmacologia

African horse sickness virus (AHSV) affects equine populations around the world. It is the cause of a high rate of morbidity and associated large economic losses in affected regions. The virus is a segmented double stranded RNA virus and a member of Orbivirus genus in the Reoviridae family. The prototype member of the orbiviruses is bluetongue virus (STY) and other members include Chuzan virus and St. Croix River virus. These viruses are all characterized by a genome of ten dsRNA segments that encode at least ten different proteins. Three of the minor core proteins are found within the core of BTV. These are all associated with the RNA transcription complex and the enzymatic activities with which they are associated include an RNA polymerase (VP1), an RNA capping enzyme (VP4) and an RNA helicase (VP6). Genes homologous to the BTV genes that encode these proteins are found in all members of the Orbivirus genus. The aim of this thesis is to characterize VP4 of AHSV, the capping enzyme candidate, and to compare it to other orbivirus capping enzymes. Possible functional motifs and regions of importance within the orbivirus capping enzymes will be identified. The gene will also be expressed and used to perform assays to characterize the different enzymatic activities of VP4. The VP4 cDNA of AHSV serotype 3 was cloned and sequenced. From the full-length verified nucleotide sequence an open reading frame was identified and used to predict the amino acid sequence. These were compared to other orbivirus species including STY, Chuzan virus and St. Croix River virus. These alignments identified a number of highly conserved regions, consisting of four or more amino acids conserved between all the sequences analyzed. A fibronectin type 3-like motif, containing 12 conserved amino acids, was identified which could be responsible for protein binding. This motif contains 12 conserved amino acids making it a good candidate for a functional motif. Conservation does not, however, always predict regions of importance. In BTV a lysine-containing motif was identified to be responsible for GMP binding. This region is not conserved between the different viruses. AHSV has a motif containing a lysine residue similar to the motif identified in rotavirus and reovirus. Two other motifs described in BTV were also not conserved in the other viruses. One of them, a leucine zipper, was shown to dimerize BTV VP4. Phylogenetically, AHSV and Chuzan virus are the most closely related while BTV is more distant and St. Croix River virus forms a distinct out-group when the different VP4 sequences are compared. AHSV-3 VP4 was expressed as a histidine-tagged protein in the baculovirus expression system. Not unexpectedly, the protein was found to be insoluble, similar to BTV VP4 produced by means of the same system. However, whereas BTV VP4 could be solubilized by the addition of salt the AHSV VP4 remained insoluble at high salt concentrations. Several adjustments were made. Cells were lysed in a high salt buffer, the pH of the buffers was adjusted and sucrose cushions were used but none of the methods was found to improve the yield of soluble VP4 significantly. However, the pellet containing VP4 was relatively empty of contaminating protein and, therefore, a number of enzymatic assays were performed with the pellet. Assays for inorganic phosphatase and nucleotide phosphatase were performed. Strikingly, both assays indicated the presence of active phosphatases in the WT and VP4 pellets. Also, an assay was performed for guanylyltransferase activity but no activity was observed for this assay. The sequence data therefore points to VP4 as the probable capping enzyme although it may have a different structural complex. The failure to produce a reliable source of soluble purified AHSV VP4 made it impossible to provide evidence to confirm the associated enzymatic activities. / Dissertation (MSc(Genetics))--University of Pretoria, 2005. / Genetics / unrestricted

Orientador: Edson Antunes / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-26T14:39:41Z (GMT). No. of bitstreams: 1 BaldisseraJunior_Lineu_D.pdf: 1965195 bytes, checksum: 107b841684637a6a66bcdb7b9e929cef (MD5) Previous issue date: 2015 / Resumo: O recrutamento de eosinófilos para o pulmão inflamado é uma característica central da asma alérgica. Há relatos de que a ativação da guanilil ciclase solúvel (GCs) exerce atividade anti-inflamatória por inibir o recrutamento de leucócitos, e que o aumento de GMPc intracelular inibe a migração in vitro de eosinófilos humanos. A GCs é estimulada pelo NO, seu agonista fisiológico. Outros compostos são capazes de estimular a GCs de forma independente do NO, como as moléculas da família dos estimuladores NO-independentes e heme-dependentes, e, mais recentemente, por compostos estimuladores NO- e heme-independentes, chamados de ativadores da GCs. Neste contexto, o objetivo deste trabalho foi avaliar os efeitos do BAY 60-2770 (ativador NO- e heme-independente da GCs) em modelo murino de asma alérgica e na quimiotaxia in vitro de eosinófilos humanos induzida pela eotaxina. Para tanto, camundongos machos C57Bl6 (25 g, 6 semanas de idade) foram sensibilizados (2 injeções s.c. de 100 ?g de ovalbumina, nos dias 0 e 7) e submetidos ao desafio intranasal com OVA (10 ?g; duas vezes por dia, com intervalos de 6 horas entre cada desafio) nos dia 14 e 15, na presença e/ou ausência (veículo) do tratamento crônico com BAY 60-2770 (1mg/Kg/gavage; 14 dias). Os animais foram anestesiados e sacrificados 48 horas após o primeiro desafio, e as amostras biológicas colhidas para análise. O perfil inflamatório alérgico foi avaliado através da contagem total e diferencial de leucócitos no lavado broncoalveolar (LBA), sangue periférico, perfusato de medula óssea (MO) e em corte histológico. Foram dosados os níveis de IgE sérica específica a OVA, citocinas Th1 (IFN-?), Th2 (IL-4, IL-5, IL-10), TNF-? e eotaxina no LBA. A expressão proteica da GCs (subunidades ?2 e ?1) e da iNOS foi quantificada no parênquima pulmonar. O desenho experimental foi dividido em quatro grupos, a saber: grupo tratado com Veículo e instilado com Salina (VS); grupo tratado com Veículo e desafiado com OVA (VO); grupo tratado com BAY 60-2770 e instilado com Salina (BS); grupo tratado com o BAY 60-2770 e desafiado com OVA (BO). Nossos resultados mostraram níveis elevados (p<0,05) de IgE em soro de animais sensibilizados comparados com animais naive, confirmando a eficácia da sensibilização, que não foi alterada pelo tratamento com BAY 60-2770. O desafio alérgico à OVA (grupo VO), como esperado, gerou uma resposta inflamatória alérgica pulmonar, caracterizada pela presença marcante de eosinófilos no pulmão e de níveis elevados de IL-4 no LBA, assim como eosinofilia sanguínea e eosinofilopoese na medula óssea. Esta resposta foi significativamente acompanhada da redução da expressão da GCs (subunidades ?1 e ?1) e aumento da expressão protéica da iNOS no parênquima pulmonar, comparada a animais não desafiados (grupo VS). Não foram observadas diferenças nos níveis de TNF-? e eotaxina no LBA entre os grupos. As citocinas IFN-? e IL-10 não foram detectadas no LBA em nenhum grupo experimental. O tratamento crônico com BAY 60-2770 (grupo BO) reduziu significativamente os níveis de IL-4 e IL-5 no LBA, inibiu a eosinofilia pulmonar (LBA), sanguínea e peri-bronquiolar, e suprimiu a eosinofilopoiese na medula óssea, os quais foram acompanhados da restauração da expressão da GCs (?1 e ?1) e da iNOS no parênquima pulmonar, comparado com o grupo desafiado tratado com veículo (grupo VO). Em experimentos separados, eosinófilos humanos de indivíduos saudáveis foram submetidos aos ensaios de quimiotaxia induzida por eotaxina (300 ng/mL) na presença do BAY 60-2770 individualmente e/ou co-incubado com inibidor da GCs, ODQ (10 ?M). Nas mesmas condições, foram determinados os níveis de GMPc intracelular, e realizado o teste de viabilidade celular por redução do MTT. A resposta quimiotática induzida por eotaxina foi significativamente inibida pelo BAY 60-2770 (10 ?M), de modo dependente de GMPc. O efeito inibitório do BAY 60-2770 foi potencializado pela prévia co-incubação com ODQ, que elevou marcantemente os níveis de GMPc intracelulares e inibiu significativamente a migração de eosinófilos frente à eotaxina nas concentrações de 1, 3 e 5 ?M de BAY 60-2770. A viabilidade celular não foi afetada pelo BAY 60-2770. Em conjunto, nossos resultados mostram que o BAY 60-2770 é capaz de reduzir a inflamação alérgica pulmonar murina, e de inibir de forma dependente de GMPc a migração de eosinófilos humanos induzida por eotaxina. Concluímos que o BAY 60-2770 apresenta potencial valor terapêutico na asma alérgica / Abstract: Eosinophil recruitment to inflamed lung is a hallmark of allergic asthma. The literature has shown that soluble guanylyl cyclase (sGC) plays a key antiinflammatory role by inhibiting leukocyte recruitment, and that increased cGMP intracellular levels inhibit human eosinophil chemotaxis in vitro. The soluble guanylyl cyclase is stimulated by NO, its physiological agonist. Other compounds are able to NO-independently stimulate sGC, such as the family of NO-independent and heme-dependent stimulators, and the NO- and heme-independent stimulators, known as sGC activators. Therefore, this study aimed to investigate the effects of BAY 60-2770 (NO- and haem-independent sGC activator) in pulmonary allergic inflammation in mice and human eosinophil chemotaxis in vitro induced by eotaxin. Part I: Male C57BL6 mice were sensitized (100 ?g of ovalbumin, s.c.; day 0 and 7) and intranasally challenged with OVA (10 ?g; twice a day, 6 h between challenges) at days 14 and 15, with BAY 60-2770 (1 mg/Kg/gavage; 14 days) and/or its vehicle. Mice were anaesthetized and exsanguinated at 48 hours post first-OVA challenge, and biological samples were collected. The inflammatory profile was evaluated by total and differential cell counts in bronchoalveolar lavage (BAL) fluids, peripheral blood, bone marrow perfusate and histological slides. Serum OVA-specific IgE levels were measured and Th1 (IFN-?), Th2 (IL-4, IL-5, IL-10) cytokines, TNF-? and eotaxin levels were quantified in BAL fluids. Soluble guanylyl cyclase subunits (?1 and ?1) and iNOS protein expression were determined in lung parenchyma. The experimental design was divided in four groups, namely: Vehicle treated-instilled with Saline (VS group); Vehicle treated-challenged with OVA (VO group); BAY 60-2770 treated-instilled with Saline (BS group) and BAY 60-2770 treated-challenged with OVA (BO group). Our results showed seric elevated IgE levels (p<0.05) in OVA-sensitized mice compared with naive animals, confirming the efficiency of sensitization procedure, which was not affected under BAY 60-2770 treatment. As expected, the OVA-challenge in VO group triggered a pulmonary allergic inflammatory response, characterized by markedly eosinophil migration to lung, elevated IL-4 levels in BAL fluid, as well as blood eosinophilia and marrow eosinophilopoiesis in bone marrow. This response was significantly accompanied by reduced GCs (subunits ?1 and ?1) and increased iNOS expression in lung parenchyma, compared with non-challenged animals (VS group). No differences on TNF-? and eotaxin levels in BAL fluids were observed among studied groups. Levels of IFN-? and IL-10 were not detected in BAL fluids of any groups. Chronic oral treatment with BAY 60-2770 (BO group) significantly reduced IL-4 and IL-5 levels in BAL fluids, inhibited pulmonary (BAL), blood and peri-bronchiolar eosinophilia, and supressed bone marrow eosinophilopoiesis, which was accompanied by restoration of sGC and iNOS expression in lung parenchyma, compared with vehicle treated group (VO). In separate experiments, isolated human eosinophils from healthy volunteers were individually incubated with BAY 60-2770 and/or previously co-incubated with the sGC inhibitor, ODQ (10 ?M), and allowed to migrate toward eotaxin (300 ng/ml; 1 h, 37°C) in chemotaxis chamber. In the same conditions, intracellular cGMP levels were determinated and cell viability test were performed by MTT reduction. Our data showed that human eosinophil migration to eotaxin was significantly inhibited by BAY 60-2770 (10 ?M) in a cGMP-dependent manner. Inhibitory effect of BAY 60-2770 was potentiated by previous co-incubation with ODQ, which markedly elevated cGMP intracellular levels and inhibited eosinophils migration induced by eotaxin at 1, 3 and 5 ?M BAY 60-2770 concentrations. The cell viability was not affected by BAY 60-2770. Together, our results show that BAY 60-2770 is able to reduce murine pulmonary allergic inflammation, and to inhibit human eosinophil migration toward eotaxin in cGMP-dependent manner. In conclusion, the compound BAY 60-2770 presents potential therapeutic value in allergic asthma / Doutorado / Farmacologia / Doutor em Farmacologia

Orientadores: Fabíola Taufic Mónica Iglesias, Edson Antunes / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-29T00:02:26Z (GMT). No. of bitstreams: 1 Fernandes_CamilaStefaniEstancial_M.pdf: 2289746 bytes, checksum: e67d3948b14883b515cd7e008bc69850 (MD5) Previous issue date: 2015 / Resumo: Duas classes de medicamentos denominadas estimuladores e ativadores da GCs foram desenvolvidas para uso terapêutico em situações patológicas, onde há menor biodisponibilidade NO ou tolerância farmacológica. A principal diferença entre os moduladores da GCs é que os ativadores atuam de maneira mais eficaz mesmo quando a enzima encontra-se no estado oxidado. O presente trabalho foi dividido em duas etapas, a saber: 1) caracterização farmacológica do ativador BAY 60-2770 em corpo cavernoso (CC) de coelho e 2) avaliação do efeito do ativador BAY 60-2770 e estimulador BAY 41-2272 da GCs em CC isolado de ratos espontaneamente hipertensos (SHR) e normotensos (WKY). O BAY 60-2770 promoveu relaxamento concentração dependente em corpo cavernoso de coelho (pEC50: 7,584 ± 0,1923), sendo este efeito potencializado na presença dos inibidores da GCs ODQ (10 µM; pEC50: 8,170 ± 0,1365) e da fosfodiesterase tipo 5 (PDE5), tadalafil (100 ?M; pEC50: 8,381 ± 0,1334). A contração induzida por estimulação elétrica foi reduzida em aproximadamente 50% na presença de BAY 60-2770, sendo este efeito potencializado na presença de ODQ. Em relação ao relaxamento induzido pela estimulação elétrica, o ODQ e BAY 60-2770 aboliu e aumentou, respectivamente o relaxamento. A co-incubação de BAY 60-2770 com ODQ não alterou o relaxamento em comparação com o ODQ sozinho. Curiosamente, quando BAY 60-2770 foi incubado 20 min antes da adição de ODQ, os relaxamentos induzidos por estimulação elétrica foram parcialmente restaurados quando comparado com o ODQ sozinho. Em relação à segunda etapa do trabalho, o relaxamento induzido pelos moduladores da GCs, BAY 60-2770 e BAY 41-2272 não diferiram em CC de ratos SHR comparados ao seu respectivo controle, porém, estes dados não corroboram com a quantificação de GMPc, no qual evidenciamos aumento dos seus níveis em CC de ratos SHR sendo estes níveis ainda maiores quando na presença de ODQ em comparação ao CC de WKY. Observamos também que o relaxamento induzido pela acetilcolina (ACh) encontrou-se reduzido em CC dos animais hipertensos, entretanto, a adição de BAY 60-2770 ou BAY 41-2272 restaurou este relaxamento. Não foi encontrada diferença na expressão das subunidades ?1 e ?1 da GCs em ratos SHR e WKY, porém quando analisamos a expressão da PDE-5, verificamos maior expressão em CC de ratos SHR. O BAY 60-2770 foi capaz de elevar a pressão intracavernosa em CC de ratos normotensos em todas as frequências estudadas, porém esta elevação somente foi significativa na frequência de 16 Hz. Considerando que 1) BAY 60-2770 induziu relaxamento em CC de coelho e de rato hipertenso de maneira mais potente que o estimulador BAY 41-2272, 2) a adição de ODQ potencializou o relaxamento do BAY 60-2770, mas não do BAY 41-2272 em CC de ambas espécies, 3) o aumento dos níveis de GMPc foi maior em CC de ratos SHR após estímulo com BAY 60-2770, mas não com BAY 41-2272 pode-se concluir que em situações patológicas onde há oxidação da GCs e/ou menor biodisponilidade de NO, os ativadores da GCs seriam mais vantajosos que os estimuladores ou inibidores da PDE5 para o tratamento da disfunção erétil / Abstract: Two classes of drugs referred to as stimulators and sGC activators have been developed for therapeutic use in pathological situations where there is less NO bioavailability and pharmacological tolerance. The main difference between the sGC activators modulators is that they act more effectively even when the enzyme is in the oxidized state. This study was divided into two stages: 1) pharmacological characterization of BAY 60-2770 activator in corpus cavernosum (CC) of rabbit and 2) evaluation of the effect of BAY 60-2770 BAY 41-2272 activator and stimulator of GCs isolated from spontaneously hypertensive rats (SHR) and normotensive (WKY). The BAY 60-2770 induced concentration-dependent relaxation in rabbit corpus cavernosum (pEC 50: 7.584 ± 0.1923), and this increased effect in the presence of GCs ODQ inhibitors (10 ?M; pEC 50: 8.170 ± 0.1365) and the phosphodiesterase type 5 (PDE5), tadalafil (100 ?m; pEC50: 8.381 ± 0.1334). The contraction induced by electric stimulation was reduced by approximately 50% in the presence of BAY 60-2770, and this increased effect in the presence of ODQ. In relation to the relaxation induced by electrical stimulation, ODQ and BAY 60-2770 abolished and increased, respectively the relaxation. Co-incubation with BAY 60-2770 with ODQ did not change compared to the relaxation with only ODQ. Curiously, when BAY 60-2770 was incubated 20 minutes before addition of ODQ, the relaxation induced by electric stimulation was partially restored when compared with only ODQ. In the second part, relaxation induced by modulators of GCs, BAY 60-2770 and BAY 41-2272 did not differ in SHR CC compared to their respective control, however, these data do not corroborate the quantification of cGMP, in which we observed an increase in their levels in SHR rats and these levels even higher in the presence of ODQ in comparing the CC of WKY. We also observed a reduction of the relaxation induced by acetylcholine (ACh) in CC of hypertensive animals, however, the addition of BAY 60-2770 or BAY 41-2272 restored this relaxation. There was no difference in the expression of ?1 and ?1 subunits of sGC in SHR and WKY rats, but when we analyzed the expression of PDE-5, we found greater expression in SHR. The BAY 60-2770 was able to raise up the intracavernous pressure in the normotensive rats in all studied frequencies, but this increase was only significant in the frequency of 16 Hz. Considering 1) BAY 60-2770 induced relaxation in rabbit and hypertensive rat so that the most potent stimulator BAY 41-2272, 2) addition of ODQ potentiated relaxation of BAY 60-2770, but not in BAY 41-2272 in CC of both, 3) increased levels cGMP was greater in SHR rats after stimulation with BAY 60-2770, but not in BAY 41-2272 so can be concluded that in pathologic situations where there is oxidation of GCs and / or low bioavailability of NO, would activators of sGC more advantageous than PDE5 inhibitors or stimulators for the treatment of erectile dysfunction / Mestrado / Farmacologia / Mestra em Farmacologia

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