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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
201

Conexões e caracterização neuroquímica de vias neurais envolvidas com o controle dos movimentos mandibulares / Connections and neurochemical characterization of neural pathways involved in the control of jaw movements

Marcelo Betti Mascaro 13 August 2007 (has links)
O núcleo motor do trigêmeo (Mo5) está cercado por um anel de neurônios pré-motores localizados na região h. Estudos demonstram que neurônios que inervam o Mo5 estão distribuídos no tronco encefálico e no prosencéfalo. Após implante de traçador retrógrado no Mo5, verificamos células retrogradamente marcadas no núcleo mesencefálico do trigêmeo (Me5), na região h e em núcleos prosencefálicos como o central da amígdala (CeA), a área hipotalâmica lateral (LH) e o parasubtalâmico (PSTh). Para confirmação, realizamos injeção de traçador anterógrado e investigamos, também, a neuroquímica das projeções. Neurônios do CeA que se projetam para o Mo5 recebem inervação de fibras imunorreativas ao fator liberador de corticotrofina (CFR-ir) e/ou à tirosina hidroxilase (TH-ir); alguns neurônios da LH que se projetam para o Mo5 são imunorreativos à orexina (ORX) e alguns neurônios do PSTh que se projetam para o Mo5 são innervados por fibras TH-ir. O Me5 recebe grande inervação do CeA e moderada da LH e do PSTh, possuindo grande aferência de fibras imunorreativas ao CRF, ORX e TH / The trigeminal motor nucleus (Mo5) is surrounded by a ring of premotor neurons defined as the h region. Studies have shown that neurons innervating the Mo5 are located in brainstem and in forebrain nuclei. Through the injection of the retrograde tracer cholera toxin b subunit/CTb in the Mo5, we found retrograde labeled neurons in the brainstem including the h region and the mesencephalic trigeminal nucleus (Me5), and in forebrain nuclei such as the central nucleus of amygdala (CeA), the lateral hypothalamic area (LH) and the parasubthalamic nucleus (PSTh). As control, we injected the anterograde tracer biotin dextran amine and found that these areas project direct or indirectly via the h region or the Me5 to the Mo5. Some CeA neurons that project to the Mo5 receive corticotrophin releasing factor (CRF) and tyrosine hydroxylase (TH) innervation, some LH neurons that project to Mo5 express orexin, and PSTh neurons that project to the Mo5 receive TH innervation. The Me5 is also innervated by CeA, LH and PSTh neurons and by CRF, orexin and TH immunoreactive fibers
202

Estudo da fenotipagem de quatro enzimas metabolizadoras de fÃrmacos em uma amostra da populaÃÃo do Estado do Cearà / A population phenotyping study of four drug-metabolizing enzymes in Cearà â Brazil

Gilmara Silva de Melo Santana 30 January 2004 (has links)
FundaÃÃo de Amparo à Pesquisa do Estado do Cearà / A caracterizaÃÃo do fenÃtipo acetilador e oxidativo das atividades das enzimas metabolizadoras à de fundamental relevÃncia para avaliaÃÃo da resposta farmacolÃgica aos vÃrios agentes terapÃuticos. Os estudos de fenotipagem e genotipagem tÃm como finalidade detectar e mensurar polimorfismos nestas enzimas. O estudo teve como objetivo determinar o perfil fenotÃpico da atividade metabolizadora das enzimas CYP1A2, CYP2A6, XO e NAT2 em uma amostra de oitenta voluntÃrios saudÃveis da populaÃÃo do estado do CearÃ, utilizando a cafeÃna como fÃrmaco âprobeâ. Os voluntÃrios foram avaliados atravÃs de consulta mÃdica para confirmaÃÃo do estado de higidez; as funÃÃes metabÃlicas, hepÃtica e renal foram avaliadas atravÃs de exames laboratoriais hematolÃgicos e bioquÃmicos. O protocolo clÃnico consistiu de um internamento onde os voluntÃrios receberam um comprimido de 200mg de cafeÃna e coletas de sangue e urina. As amostras de sangue seguiram os seguintes intervalos a partir da administraÃÃo: 0; 0:05; 0:15; 0:25; 0:35; 0:45; 1:00; 1:15; 1:30; 2; 4; 6; 8; 12 e 24 horas. A urina foi colhida em seu volume total durante as 10 horas apÃs a administraÃÃo, o volume urinÃrio total foi quantificado e uma alÃquota foi armazenada para determinaÃÃo dos metabÃlitos. O protocolo analÃtico consistiu de dosagem por HPLC das concentraÃÃes plasmÃticas de cafeÃna e das concentraÃÃes urinÃrias dos cinco principais metabÃlitos da cafeÃna: 1U â Ãcido 1-metilÃrico; 17U â Ãcido 1,7-dimetilÃrico; 1X â metilxantina; 17X â 1,7-dimetilxantina e AFMU â 5-acetilamino-6-formilamino-3-metiluracil. A partir das concentraÃÃes molares urinÃrias dos metabÃlitos foram determinadas as atividades das enzimas: CYP1A2 = (AFMU + 1X + 1U)/ 17U; CYP2A6 = 17U / (AFMU + 1X + 1U + 17X + 17U); NAT2 = AFMU/ (AFMU + 1X + 1U) e XO = 1U/ (1X + 1U). Os valores das atividades enzimÃticas foram submetidos a anÃlise por estatÃstica descritiva (histograma) nÃo apresentando distribuiÃÃo normal. Foram identificados pelo menos trÃs fenÃtipos metabolizadores para as enzimas CYP1A2, NAT2 e XO. Com base na atividade de cada enzima os voluntÃrios foram divididos em dez grupos organizados categoricamente. Os voluntÃrios dos grupos de maior e menor atividade enzimÃtica foram escolhidos para determinaÃÃo dos parÃmetros farmacocinÃticos (ASC; t1/2; ke; Vd/Kg; CL). A comparaÃÃo destes parÃmetros (teste âtâ de Student) entre os dois grupos apresentou diferenÃas significantes (p<0,05). Nossos resultados sugerem a existÃncia de polimorfismo nas enzimas estudadas de acordo com a heterogeneidade das atividades enzimÃticas na amostra da populaÃÃo de voluntÃrios saudÃveis do estado do CearÃ. / Characterization of acetylator and oxidative metabolizers phenotypes is of clinical relevance, as it has been shown that the pharmacological response of several therapeutic agents. The studies of phenotypage and genotipage have as purpose to detect and to mensurar polimorfismos in these enzymes. In this study, we assessed in vivo activities of CYP1A2, CYP2A6, Xantine Oxidase (XO) and NAT2 in sample of 82 volunteers (40 men and 42 women) from Cearà â Brazil using caffeine as probe. The volunteers were free from significant cardiac, hepatic, renal, pulmonary, gastrointestinal and hematological disease, as assessed by physical investigation, ECG and hematological and biochemical tests. The study was open, the volunteers were hospitalized, having already had a normal evening meal, and after an overnight fast they received a single 200 mg dose of caffeine tablet. Blood samples were collected in regular interview ( 0; 5min; 15min; 25min; 35min; 45min; 1h; 1,25h; 1,5h; 2h; 4h; 6h; 8h; 12h and 24 hour) after the administration of caffeine. Urine was harvested in its total volume during the 10 hours after the administration of caffeine, the total urinÃrio volume was quantified and an aliquot one was stored for determination of the metabÃlitos. The caffeine was determined in human plasma and the metabolites were determined in human urinary by HPLC using teobromina as an internal standard. The metabolites assessed were: 1U â 1-methyluric acid; 17U â 1, 7-dimethyluric acid; 1X â 1-methylxantine; 17X â 1, 7-1-dimethylxantine e AFMU â 5-acetylamino-6-formylamino-3methyluracil. The following molar ratios were calculated as an index for CYP1A2 activity [(AFMU + 1X + 1U)/ 17U]; CYP2A6 activity [17U / (AFMU + 1X + 1U + 17X + 17U)]; NAT2 activity [AFMU/ (AFMU + 1X + 1U)] and Xanthine Oxidase activity [1U/ (1X + 1U)]. The enzymatic activities were plotted in histogram. The frequency distributions of the CYP1A2, CYP2A6, XO and NAT2 were not normally distributed, showing three phenotypes. Afterwards the volunteers were classified by enzymatic activities in ten groups, and the lowest and highest metabolizers groups were chosen to determine the following pharmacokinetic parameters: AUC0-24, t1/2, ke, CL and Vd/Kg. The comparison of these parameters (test âtâ de Student) between these two groups it showed significant differences (p<0.05). Our findings may suggest that the heterogeneous population assessed (health volunteers from Cearà - Brazil) has shown polymorphism in the enzymatic activities of the CYP1A2, NAT2, XO and CYP2A6
203

Estudo do efeito bioquímico e estrutural de novas mutações em enzimas da esteroidogênese / Study of the biochemistry and structural effects of rare mutations in steroidogenesis enzymes

Lusa, Ana Leticia Gori, 1983- 05 March 2013 (has links)
Orientadores: Maricilda Palandi de Mello, Fernanda Caroline Soardi / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-23T09:56:23Z (GMT). No. of bitstreams: 1 Lusa_AnaLeticiaGori_D.pdf: 4582728 bytes, checksum: a14d0d0453e90b4a59cb02532b21d83b (MD5) Previous issue date: 2013 / Resumo: A Hiperplasia congênita da Adrenal (HCA) é uma das doenças mais comuns com herança autossômica recessiva. Uma das causas é a deficiência da 21-hidroxilase que surge por mutações no gene CYP21A2. O desequilíbrio na síntese de cortisol causa um estímulo excessivo das glândulas adrenais pelo hormônio adrenocorticotrópico (ACTH) e, consequentemente, à hiperplasia da glândula e ao aumento na síntese de andrógenos. O presente trabalho teve por objetivo clonar e expressar variantes do gene CYP21A2 e, avaliar as variantes enzimáticas da 21-hidroxilase quanto à atividade residual, comparando suas formas nativa e mutantes. Foi também realizado o estudo in silico para se comparar as estruturas das enzimas 21-hidroxilase e 3?-hidroxiesteróide desidrogenase tipo 2 (HSD3B2) avaliando o impacto das alterações provocadas por mutações sobre a estrutura da proteína nativa. Para a enzima 21-hidroxilase, as mutações analisadas quanto à atividade foram: p.Ser113Phe, p.Pro267Leu, p.Val358Ile, p.Arg426Cis e, as combinações p.Ile172Asn+p.Val358Ile e p.Val281Leu+p.Arg426Cis. Nos testes de atividade enzimática, as enzimas com as mutações p.Val358Ile e as combinações p.Ile172Asn+p.Val358Ile e p.Val281Leu+p.Arg426Cis apresentaram valores de atividade residual compatíveis com a forma perdedora de sal. Por outro lado, a enzima com a mutação p.Pro267Leu apresentou atividade residual maior que 50%, compatível com mutações da forma não clássica. As mutações p.Ser113Phe e p.Arg426Cis, por sua vez, apresentaram atividade residual entre 2 e 7% que, em relação aos controles utilizados, foram correspondentes à forma clássica virilizante simples. Os modelos estruturais gerados para as enzimas 21-hidroxilase portadoras da deleção p.(Gln389_Ala391del) e das mutações individuais ou combinadas acima citadas foram comparados ao da enzima nativa. Estudo similar foi realizado com enzimas HSD3B2 nativa e portadoras de duas mutações, p.Pro222Gln e p.Pro222Thr, relacionadas à forma perdedora de sal da deficiência de HSD3B2. Esse estudo demonstrou boa correlação das mutações encontradas nos pacientes com os seus fenótipos tanto no que diz respeito à atividade enzimática quanto às alterações estruturais. Assim, ficou demonstrado que este tipo de abordagem é eficaz para a avaliação dos aspectos funcionais de mutações inéditas / Abstract: Congenital adrenal hyperplasia (CAH) is one of the most common hereditary autosomal recessive diseases. 21-hydroxylase deficiency is one important cause of the disease and results from mutations in CYP21A2 gene. The unbalance in cortisol synthesis leads to excessive stimulation of adrenal glands by adrenocorticotropic hormone (ACTH), consequently, to adrenal hyperplasia and excessive androgen synthesis. The present study aimed to obtain and express CYP21A2 clones carrying sequence variations and to evaluate 21-hydroxylase enzymatic residual activities of variant enzymes in comparision to the wild-type. In silico studies were also performed to compare the structure of 21-hydroxylase and 3?-hydroxysteroid dehydrogenase type 2 (HSDB2) evaluating the impact of mutations upon the native structure of the enzymes. Residual activity analyses for 21-hydroxylase enzyme comprised the mutations p.Ser113Phe, p.Pro267Leu, p.Val358Ile and the combined mutations p.Ile172Asn+p.Val358Ile and p.Val281Leu+p.Arg426Cys. The assays indicated that p.Val358Ile and p.Ile172Asn+p.Val358Ile and p.Val281Leu+p.Arg426Cys reduced CYP21A2 activity to levels corresponding to the salt wasting form. Whereas the enzyme bearing p.Pro267Leu mutation showed residual activity higher than 50% indicating a nonclassic mutation. Conversely, p.Ser113Phe and p.Arg426Cys mutations showed residual activities that varied between 2% and 7% that, compared to controls, corresponded to simple virilizing form. Structural models generated for 21-hydroxylase enzyme with p.(Gln389_Ala391del) and each individual or combined mutations cited above have been compared to the native enzime. Similar study was performed with HSD3B2 enzyme in its native and mutated formas with p.Pro222Gln e p.Pro222Thr that are related to the salt wasting form of HSD3B2 deficiency. This study demonstrated a good genotype-phenotype correlation in patients either for residual activities or for structural changes. Therefore, it has been demonstrated that such analyses are effective to evaluate functional aspects for novel mutations / Doutorado / Genetica Animal e Evolução / Doutora em Genética e Biologia Molecular
204

Lysyl hydroxylases 1 and 2:characterization of their <em>in vivo</em> roles in mouse and the molecular level consequences of the lysyl hydroxylase 2 mutations found in Bruck syndrome

Hyry, M. (Marjo) 29 May 2012 (has links)
Abstract The extracellular matrix is not just a scaffold for cells and tissues, but rather a dynamic part of the human body. Characteristics of collagens, the major protein components of the extracellular matrix, are determined already during synthesis and mutations in genes encoding collagens, unbalance of regulators or dysfunction of collagen modifying enzymes, for instance, can lead to severe clinical complications. Certain hydroxylysine residues formed by lysyl hydroxylases (LHs) function in collagens as precursors of collagen cross-links that stabilize collagenous structures and thereby tissues. In humans, a deficiency of LH1, which is known to hydroxylate lysines in the helical regions of collagen polypeptides, causes Ehlers-Danlos syndrome VIA (EDS VIA). It is characterized e.g. by progressive kyphoscoliosis and hypermobile joints. Mutations in LH2, which is known to hydroxylate lysines in the telopeptides of collagen polypeptides, cause Bruck syndrome type 2 (BS2). BS2 patients suffer from fragile bones and congenital joint contractures, for instance, but the syndrome is usually not lethal. In this work we have generated and analyzed genetically modified LH1 and LH2 null mouse lines to study the in vivo functions and roles of these enzymes. Analyses concentrated also on collagen cross-links that were determined from several null or heterozygous mouse tissues. In the present work we also studied the effects of known BS2 mutations on recombinant human LH2 polypeptides to understand the molecular pathology of the syndrome. As an animal model for human EDS VIA, LH1 null mice had certain characteristics typical for EDS VIA, such as muscular hypotonia, but generally the symptoms were milder. Like EDS VIA patients, the mice have an increased risk of arterial ruptures and ultrastructural changes can be seen in the wall of the aorta, explained by inadequate helical lysine hydroxylation accompanied by a changed cross-linking state of tissues. Similarly, analysis of the LH2 null mouse line demonstrated the importance of the enzyme in cross-link formation. We showed that even a reduced amount of LH2 in adult mice changes the cross-linking pattern in tissues and a total lack of the enzyme leads to embryonic lethality. Furthermore, we demonstrated that LH2 is particularly important in tissue structures supporting blood vessels in the developing mouse embryo or in extraembryonic tissues. Finally, our in vitro studies with recombinant human LH2 polypeptides revealed that the known BS2 mutations severely affect the activity of the enzyme thus explaining the clinical symptoms of the patients, but the mutations do not lead to a total inactivation of the enzyme, which may be critical for the survival of patients. / Tiivistelmä Solunulkoinen matriksi ei ole ainoastaan soluja ja kudoksia tukeva rakenne, vaan se on dynaaminen osa ihmiskehoa. Kollageenien, solunulkoisen matriksin yleisimpien proteiinien ominaisuudet määräytyvät jo kollageenien synteesivaiheessa ja mutaatiot kollageeneja koodittavissa geeneissä, säätelytekijöiden epätasapaino tai esimerkiksi kollageeneja muokkaavien entsyymien toimintahäiriöt voivat johtaa vaikeisiin kliinisiin komplikaatioihin. Tietyt lysyylihydroksylaasien (LH) muodostamat hydroksilysiinitähteet toimivat kollageeneissa kollageeniristisidosten esiasteina. Ristisidokset vakauttavat kollageenirakenteita ja siten myös kudoksia. LH1 hydroksyloi lysiinejä kollageenipolypeptidien kolmoiskierteisellä alueella ja ihmisellä entsyymin puutos aiheuttaa tyypin VIA Ehlers-Danlosin syndrooman (EDS VIA), jossa potilailla on esimerkiksi etenevää kyfoskolioosia ja yliliikkuvat nivelet. Mutaatiot LH2-entsyymissä, joka hydroksyloi lysiinejä kollageenipolypeptidien telopeptidialueilla, aiheuttavat tyypin 2 Bruckin syndrooman (BS2). BS2-potilaat kärsivät mm. luiden hauraudesta ja niveljäykkyydestä, mutta syndrooma ei yleensä ole letaali. Tässä työssä loimme ja analysoimme geneettisesti muunnellut LH1 ja LH2 hiirilinjat, joiden kyseinen LH-geeniaktiivisuus on hiljennetty. Linjojen avulla halusimme tutkia näiden entsyymien toimintaa ja merkitystä in vivo. Analyysit keskittyivät myös kollageeniristisidoksiin, joita tutkittiin useista poistogeenisten tai heterotsygoottisten hiirten kudoksista. Ymmärtääksemme BS2:n molekyylipatologiaa, tutkimme tässä työssä myös tunnettujen BS2-mutaatioiden vaikutuksia ihmisen LH2-rekombinanttiproteiinissa. EDS VIA:n eläinmallina LH1 poistogeenisillä hiirillä on joitakin ominaisuuksia, kuten lihashypotonia, jotka ovat tyypillisiä EDS VIA:lle, mutta yleisesti oireet ovat lievempiä. Kuten EDS VIA-potilailla, hiirillä on kohonnut valtimoiden repeytymisriski ja aortan seinämän ultrarakenteessa voidaankin havaita muutoksia. Oireita voidaan selittää riittämättömällä kollageenien kolmoiskierteisen alueen lysiinien hydroksylaatiolla, joka muuttaa kollageenien ristisidostilaa kudoksissa. Myös LH2-hiirilinjan analysointi osoitti kyseisen entsyymin tärkeyden ristisidosten muodostamisessa. Jo alentunut LH2:n määrä aikuisissa hiirissä muuttaa kudosten kollageeniristisidoksia ja täydellinen entsyymin puuttuminen johtaa sikiön kuolemaan. Lisäksi osoitimme, että LH2 on erityisen tärkeä kudosrakenteissa, jotka tukevat kehittyvän hiiren sikiön tai sikiön ulkopuolisten kudosten verisuonia. In vitro-tutkimukset ihmisen LH2-rekombinanttiproteiinilla paljastivat, että tunnetut BS2-mutaatiot vaikuttavat erittäin haitallisesti entsyymin toimintaan, mikä selittää potilaiden kliiniset oireet, mutta mutaatiot eivät kuitenkaan aiheuta entsyymin täydellistä inaktivaatiota, mikä voi olla kriittistä potilaiden selviytymisen kannalta.
205

Hypoxia-inducible factor prolyl 4-hydroxylase-2 in Tibetan high-altitude adaptation, extramedullary erythropoiesis and skeletal muscle ischemia

Myllymäki, M. (Mikko) 07 June 2016 (has links)
Abstract Adequate oxygen supply is necessary for aerobic cell survival. Cellular oxygen deprivation, also known as hypoxia, leads to various responses that aim to increase cellular oxygen delivery and reduce oxygen consumption. Oxygen homeostasis is mainly regulated by the hypoxia-inducible factor (HIF), which regulates the expression of over 300 genes in response to hypoxia. The stability of HIF is regulated by the HIF prolyl 4-hydroxylases (HIF-P4Hs), enzymes that catalyze the hydroxylation of proline residues in HIFα subunits and target them towards proteasomal degradation. HIF-P4Hs require oxygen as a cosubstrate for the reaction, allowing for hypoxic HIF stabilization and target gene induction at low oxygen concentrations. In this study we investigated the role of HIF-P4H-2 in the regulation of red blood cell production, erythropoiesis. We showed that Tibetans living at high altitude have genetically adapted to their hypoxic environment via mutations in the gene encoding for HIF-P4H-2. The Tibetan HIF-P4H-2 D4E,C127S variant showed enhanced hydroxylation of HIFα at low oxygen concentrations, resulting in reduced HIFα protein stabilization under hypoxia. In other studies we used a genetically modified HIF-P4H-2 hypomorphic mouse line which expresses a reduced amount of wild-type Hif-p4h-2 mRNA in tissues. We showed that these mice develop mild age-dependent erythrocytosis due to splenic extramedullary erythropoiesis, which is independent of serum erythropoietin concentration. In addition, these mice were protected against inflammation-induced anemia, a condition commonly seen in patients with inflammatory diseases. The HIF-P4H-2 hypomorphic mice also had altered basal metabolism in their skeletal muscles, which, together with an increase in mean capillary area, reduced their infarct size after skeletal muscle ischemia-reperfusion injury. These studies suggest that pharmacological HIF-P4H-2 inhibition may provide a novel treatment for EPO-resistant anemias and peripheral artery disease. / Tiivistelmä Riittävä hapensaanti on välttämätöntä aerobisten solujen selviytymiselle. Solun alentunut hapen määrä, toiselta nimeltään hypoksia, johtaa useisiin vasteisiin joiden tarkoituksena on turvata solun hapensaanti ja vähentää hapenkulutusta. Happitasapainoa säätelee hypoksiassa indusoituva tekijä (HIF), joka aktivoi yli 300 geenin luentaa hypoksisissa oloissa. HIF&#945;:n määrää soluissa säätelevät HIF prolyyli-4-hydroksylaasientsyymit (HIF-P4H:t), jotka hydroksyloivat proliini-aminohappotähteitä HIF&#945;-alayksiköissä ja ohjaavat ne proteasomaaliseen hajotukseen. HIF-P4H:t tarvitsevat reaktiossa happea mahdollistaen HIF:n stabilisaation ja kohdegeenien lisääntyneen luennan matalassa hapen osapaineessa. Tässä tutkimuksessa selvitimme HIF-P4H-2-entsyymin roolia punasolujen muodostuksen eli erytropoieesin säätelyssä. Osoitimme, että korkealla vuoristossa asuvat tiibetiläiset ovat geneettisesti sopeutuneet hypoksiseen elinympäristöönsä johtuen HIF-P4H-2-entsyymiä tuottavan geenin mutaatiosta. Tiibetiläisiltä löytynyt HIF-P4H-2D4E,C127S variantti hydroksyloi tehokkaammin HIF&#945;-alayksiköitä matalassa hapen osapaineessa johtaen vähäisempään HIF&#945;-alayksiköiden stabiloitumiseen hypoksiassa. Muissa tutkimuksissamme käytimme geneettisesti muunneltua HIF-P4H-2-hiirikantaa, joka tuottaa alentunutta määrää villityypin Hif-p4h-2 lähetti-RNA:ta kudoksissaan. Näille hiirille kehittyi ikäriippuvaisesti lievä punasoluylimäärä eli erytrosytoosi johtuen pernan kiihtyneestä punasolutuotannosta riippumatta seerumin erytropoietiinikonsentraatiosta. Lisäksi nämä hiiret olivat suojassa tulehduksen aiheuttamalta anemialta, joka on yleinen ilmiö tulehduksellisista sairauksista kärsivillä potilailla. HIF-P4H-2-muuntogeenisten hiirten lihasten energia-aineenvaihdunta oli muuttunut siten, että se yhdessä suurentuneen keskimääräisen kapillaaripinta-alan kanssa pienensi vaurioituneen kudoksen pinta-alaa alaraajaiskemia-altistuksen jälkeen. Nämä tutkimukset osoittavat, että lääkkeellinen HIF-P4H-2-entsyymin estäminen on mahdollinen uusi hoitomuoto erytropoietiinille resistenteissä anemioissa sekä alaraajojen valtimoahtaumataudissa.
206

Expression of lysyl hydroxylases and characterization of a novel disorder caused by mutations in the lysyl hydroxylase 3 gene

Salo, A. (Antti) 18 August 2009 (has links)
Abstract Collagens and collagenous proteins undergo several post-translational modifications that are important for their structure and functions. Lysine hydroxylation produces hydroxylysines, which are important for collagen cross-link formation and provide attachment sites for galactose and glucosylgalactose. Glycosylated hydroxylysines are crucial for embryonic development and the assembly of certain collagen types. They may also facilitate interactions between collagen and adjacent molecules as well as control the diameter of collagen fibrils. Lysine hydroxylation is catalyzed by three lysyl hydroxylases (LH1, LH2 and LH3). In addition to lysyl hydroxylase activity, LH3 possesses collagen galactosyltransferase (GT) and glucosyltransferase (GGT) activities. In this study, polyclonal antibodies against the lysyl hydroxylase isoforms were produced for protein level studies to localize the expression and understand the functions of the different isoenzymes. The results indicated ubiquitous expression during embryonic development compared to the more restricted, cell and tissue specific expression patterns observed in adult mouse tissues. Differences were seen also in the alternative splicing of LH2 during embryogenesis and between tissue types. Analyses of the subcellular localization revealed that LH3 is also present in extracellular space. Tissue and cell specific differences were noted in the distribution of LH3 between cellular compartments. Substrate analysis suggested an additional and novel role for LH3 as an enzyme catalyzing lysine modifications of collagenous proteins in the extracellular space. The importance of LH1 and LH2 has been highlighted in Ehlers-Danlos type VI and Bruck syndromes, respectively. In this study, the lysyl hydroxylase 3 gene was linked to a heritable disorder for the first time. Urinary screening revealed a patient that lacked a glucosylgalactosyl derivative of a pyridinium cross-link. The GGT activity levels measured from the patient’s serum and lymphoblastoid cells were also reduced, which suggested a defect in the lysyl hydroxylase 3 gene. Genetic analyses revealed two mutations, one in each allele of LH3 in this compound heterozygous patient. Recombinant mutant proteins showed defects in lysyl hydroxylase and collagen glycosyltransferase activities, respectively. In conclusion, it was shown that a defect in LH3 catalyzed modifications leads to a novel disorder, which shares features with many other connective tissue disorders.
207

Hypoxia-inducible factor prolyl 4-hydroxylases regulating erythropoiesis, and hypoxia-inducible lysyl oxidase regulating skeletal muscle development during embryogenesis

Laitala, A. (Anu) 02 December 2014 (has links)
Abstract Erythropoiesis is the process of red blood cell production. The main regulator is the erythropoietin (EPO) hormone, which is strongly upregulated in low oxygen concentration (hypoxia) in cells via the hypoxia-inducible transcription factor HIF. The stability of HIF is regulated in an oxygen-dependent manner by three HIF prolyl 4-hydroxylases, all of which are known to participate in the regulation of erythropoiesis. A role in erythropoiesis of a fourth prolyl 4-hydroxylase, P4H-TM, which possesses a transmembrane domain, is not known, but it is able to hydroxylate HIF at least in vitro and in cellulo. The role of P4H-TM in erythropoiesis was studied by administering a HIF-P4H inhibitor, FG-4497, to P4h-tm null, Hif-p4h-3 null, and Hif-p4h-2 hypomorph mouse lines. The current study suggests that P4H-TM is involved in the regulation of EPO production, hepcidin expression and erythropoiesis. P4H-TM can thus be a new target for inhibition when designing novel pharmacological treatment strategies for anemia. LOX is required for crosslink formation between lysine residues in fibrillar collagens and elastin. These crosslinks enhance the tensile strength of collagen fibers and provide elasticity to elastic fibers and thus generate important structural support for tissues. LOX is required for normal embryonic development of the cardiovascular and pulmonary systems, and its depletion leads to a generalized elastinopathy and collagenolysis leading to perinatal death of Lox null mice. The development of muscles is a delicate process, which requires coordinated signaling and a homeostatic balance between the muscle and muscle connective tissue. Based on the drastic defects that were found in the present study in the skeletal muscle of Lox null mice, lack of LOX clearly disturbs this balance and increases transforming growth factor β (TGF-β) signaling, which leads to defects in the skeletal muscles. The impaired balance can cause muscle disorders, such as Duchenne Muscular Dystrophy (DMD). Despite the clinical significance, very little is known about the mechanisms controlling this homeostatic balance. The discovery of LOX as a regulating factor during skeletal muscle development will help to clarify the role of extracellular matrix (ECM) in muscle development and in muscle related congenital diseases. / Tiivistelmä Erytropoieesi on fysiologinen prosessi, jossa tuotetaan veren punasoluja ja jonka pääsäätelijänä toimii erytropoietiini (EPO) hormoni. EPO:n geeni ilmentyy voimakkaasti alhaisessa happipitoisuudessa (hypoksia) hypoksia-indusoituvan transkriptiotekijän (HIF) toimesta. HIF-tekijän stabiilisuutta säätelee kolme HIF-prolyyli-4-hydroksylaasientsyymiä (HIF-P4H) hapesta riippuvaisesti, ja niiden tiedetään siten osallistuvan myös erytropoieesin säätelyyn, HIF-P4H-2:n toimiessa pääsäätelijänä. Neljännen transmembraanisen prolyyli-4-hydroksylaasin (P4H-TM) roolia erytropoieesissa ei vielä tiedetä, mutta sen tiedetään säätelevän HIF-tekijää. Työssä käytettiin Hif-p4h-2, Hif-p4h-3 ja P4h-tm muuntogeenisiä hiirilinjoja, joiden entsymaattinen aktiivisuus on alentunut tai poistettu. P4H-TM:n osallisuutta erytropoieesin säätelyyn tutkittiin antamalla hiirilinjoille HIF-P4H-entsyymejä inhiboivaa lääkettä. Tutkimuksen tulokset osoittavat ensimmäistä kertaa P4H-TM:n säätelevän EPO-geenin ilmentymistä ja siten erytropoieesia. Ennestään tiedettyjen HIF-P4H entsyymien inhiboinnin lisäksi P4H-TM:n inhibointia voidaan pitää uutena kohteena uusien farmakologisten hoitokeinojen kehityksessä. Lysyylioksidaasi (LOX) katalysoi säikeisten kollageenien välisten sekä elastisten säikeiden välisten poikkisidosten muodostumista. Pokkisidokset antavat vetolujuutta kollageeneille ja joustavuutta elastisille säikeille ja ovat siten tärkeitä kudoksen rakenteelle. LOX:ia tarvitaan sikiön kehityksen aikana mm. hengitys-, sydän- ja verisuonielimistöjen kehityksessä. LOX:in puutos hiirillä aiheuttaa viallisia elastisia- ja kollageenisäikeitä, johtaen poikasten kuolemaan synnytyksen yhteydessä. Lihasten kehitys on tarkoin säädelty prosessi, jossa lihas ja lihaksen sidekudos säätelevät toisiansa. LOX:n suhteen poistogeenisissä Lox-/- sikiöissä löydettiin selviä ongelmia luurankolihasten kehityksessä. LOX:n puutoksen osoitettiin lisäävän transformoivan kasvutekijä beetan (TGF-β) määrää, joka estää luustolihaksia kehittymästä normaalisti. LOX kykenee sitoutumaan TGF-β:aan ja inhiboimaan sen aktiivisuutta ja LOX:n puuttuessa inhibointia ei tapahdu. Tutkimus osoittaa LOX:n olevan keskeinen tekijä lihaksen kehityksessä ja siten auttaa ymmärtämään sidekudoksen merkitystä luurankolihasten kehityksessä ja siihen liittyvissä sairauksissa.
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Hypoxia-inducible factor prolyl 4-hydroxylase-2 in cardiac and skeletal muscle ischemia and metabolism

Karsikas, S. (Sara) 31 March 2015 (has links)
Abstract Oxygen is essential for aerobic organisms, as shortage of oxygen (hypoxia) can induce cellular dysfunctions and even cell death, leading to tissue damage and decreased viability of the organism. Oxygen homeostasis is regulated delicately by several mechanisms, the major one being the hypoxia-inducible factor (HIF) pathway that is evolutionarily conserved. HIFα subunits are regulated in an oxygen-dependent manner via three HIF prolyl 4-hydroxylases (HIF-P4Hs). In the presence of oxygen HIF-P4Hs modify HIFα, which leads to its degradation, whereas in hypoxia the HIF-P4H enzymes cannot function and HIFα is stabilized. HIF regulates more than 300 genes that enhance oxygen delivery from the lungs to tissues and reduce oxygen consumption in tissues, such as those for erythropoietin and vascular endothelial growth factor. When a tissue suffers from hypoxia caused by a circulatory restriction, the situation is called ischemia. In this study we used a genetically modified HIF-P4H-2 hypomorph mouse line that expresses 8% of the wild-type Hif-p4h-2 mRNA in the heart and 19% in skeletal muscle, and has HIFα stabilization in both tissues. We showed that chronic HIF-P4H-2 deficiency leads to protection against acute ischemic injury both in the heart and in skeletal muscle. The protection was mainly due to enlarged capillaries and better perfusion in both tissues. Hypoxia is known to decrease body weight. The observation of the HIF-P4H-2 deficient mice being leaner than their wild-type littermates led us to study their body constitution, metabolism and adipose tissue in detail. We discovered that chronic HIF-P4H-2 deficiency protects against obesity and several metabolic dysfunctions including diabetes and metabolic syndrome. These beneficial outcomes were mimicked when a pharmacological pan-HIF-P4H inhibitor was administered to wild-type mice. In these studies we showed that pharmacological HIF-P4H-2 inhibition may provide a novel treatment for diseases such as acute myocardial infarction, peripheral artery disease and metabolic disorders. / Tiivistelmä Happi on edellytys aerobisen eliön, kuten ihmisen, elämälle; hapen niukkuus (hypoksia) voi johtaa monenlaisiin solun toimintahäiriöihin, jotka voivat edelleen aiheuttaa solun kuoleman, kyseisen kudoksen vaurion, ja lopulta eliön elinkyvyn heikkenemisen. Happitasapainoa säädellään monilla menetelmillä, joista merkittävin on hypoksiassa indusoituvasta tekijästä (HIF) riippuvainen reitti, joka on evoluutiossa säilynyt. HIFα alayksiköitä säätelee hapesta riippuvaisesti kolme HIF prolyyli 4-hydroksylaasia (HIF-P4Ht). Hapen läsnä ollessa HIF-P4H on aktiivinen ja johtaa HIFα:n hajottamiseen, kun taas hypoksiassa HIF-P4H entsyymit eivät voi toimia ja siten HIFα stabiloituu. HIF säätelee yli 300 geeniä, jotka edistävät hapen kuljetusta ja pääsyä keuhkoista kudoksiin sekä vähentävät hapenkulutusta. Näitä geenejä ovat mm. erytropoietiini sekä vaskulaarinen endoteelikasvutekijä. Kudoksen heikentyneestä verenkierrosta johtuvaa hapenpuutetta kutsutaan iskemiaksi. Tässä tutkimuksessa käytimme geneettisesti muunneltua HIF-P4H-2 hypomorfi-hiirikantaa, joka tuottaa Hif-p4h-2 lähetti-RNA:ta sydämessä vain 8 % ja luurankolihaksessa 19 % villityypin määrästä, ja jolla on HIFα stabiloituneena molemmissa kudoksissa. Osoitimme, että krooninen HIF-P4H-2:n puute suojaa sekä sydäntä että luurankolihasta akuutissa iskemiassa. Vaikutus johtui pääasiassa suuremmista kapillaareista ja paremmasta perfuusiosta molemmissa kudoksissa. Aikaisempien tutkimusten perusteella tiedetään, että hypoksia alentaa painoa. Huomio siitä, että HIF-P4H-2 puutteiset hiiret ovat hoikempia kuin villityypin sisaruksensa, johti meidät tutkimaan hiirten kehon koostumusta, aineenvaihduntaa ja rasvakudosta tarkemmin. Tutkimuksissamme selvisi, että krooninen HIF-P4H-2:n puute suojaa lihavuudelta ja monelta aineenvaihdunnan häiriöltä kuten sokeritaudilta ja metaboliselta oireyhtymältä. Nämä edulliset vaikutukset toistuivat, kun annoimme villityypin hiirille pan-HIF-P4H inhibiittoria. Kaiken kaikkiaan, näissä tutkimuksissa osoitimme, että lääkkeellinen HIF-P4H-2:n estäminen voi tarjota uuden keinon sydäninfarktin, luurankolihasiskemian ja aineenvaihdunnan häiriöiden hoitoon.
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Enzymy kvasinky Candida tropicalis biodegradující fenol / Enzymes of Candida tropicalis yeast biodegrading phenol

Koubková, Zuzana January 2011 (has links)
Effluents of industrial wastewaters from oil refineries, paper mills, dyes, ceramic factories, resins, textiles and plastic contain high concentrations of aromatic compounds, which are toxic to organisms. Degradation of these compounds to tolerant limits before releasing them into the environment is an urgent requirement. Candida tropicalis yeast is an important representative of eucaryotic microorganisms that are able to utilize phenol. During the first phase of phenol biodegradation, cytoplasmatic NADPH-dependent phenol hydroxylase of C. tropicatis oxidizes phenol to catechol. Catechol is in the second phase of biodegradative process oxidized to cis,cis-muconic acid by the reaction catalyzed with catechol-1,2-dioxygenase. In this diploma thesis we investigated the effect of the heavy metal ions on NADPH-dependent phenol hydroxylase and catechol-1,2-dioxygenase of C. tropicalis. Phenol hydroxylase was inhibited by Cu2+ and Pb2+ ions. Catechol dioxygenase was inhibited by all substances containing heavy metal ions (Fe2+ , Mn2+ , Cd2+ , Cu2+ and Pb2+ ), which were tested in this work. The most effective inhibition was produced by Pb2+ followed by Mn2+ , Cd2+ Fe2+ and Cu2+ ions. The higher sensitivity of catechol-1,2-dioxygenase to heavy metal ions might follow from the presence of histidine residue...
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Hypoxia and hematopoietic stem cell control with the substance Adaptaquin : An evaluation of hematopoietic stem cell’s proliferation and differentiation in artificially induced hypoxia

Christiansen, Jens January 2023 (has links)
Hematopoietic stem cells (HSCs) have historically been difficult to maintain ex vivo with many attempts to culture them in vitro by mimicking their natural biological environment. Providing a hypoxic environment is one way to achieve this goal and can be performed by using hypoxia stimulating compounds that inhibits the degradation of HIF1a which plays an important role in regulating hypoxia. For each sample 50 murine HSCs were isolated with fluorescence-activated cell sorting (FACS) and cultured with different concentrations of the hypoxia inducible compound Adaptaquin for 13 days followed by analysing with flow cytometry. The results showed an increase in proliferation of treated cells with the highest average total viable cell count for cells treated with 100 nM Adaptaquin of 4,70 ± 1,12 x 105 cells compared to the control which had 2,39 ± 0,76 x 105 cells. The HSC frequency was highest in the control samples with an average of 1,91 ± 0,42 % compared to the 5 mM treated samples with the highest average HSC frequency which was 1,52 ± 0,82 %. The biggest noticeable difference between the control and treated samples was seen when observing the total cell count. The difference in proliferation was on the other hand too small to see significant difference between the samples. The conclusion is that Adaptaquin did not have any significant impact on keeping the cells undifferentiated but could have a potential to be used as a compliment to other factors to maintain HSCs in vitro and to mimic its hypoxic biological environment. / Hematopoetiska stamceller (HSCs) har historiskt sett varit svåra att odla ex vivo och många försök har genomförts in vitro genom att efterlikna deras naturliga biologiska miljö. Att tillhandahålla en hypoxisk miljö är en metod för att uppnå detta och kan göras med användning hypoxi-stimulerande substanser som hämmar nedbrytningen av HIF1a som spelar en viktig roll i regleringen av hypoxi. För varje prov isolerades 50 murina HSCs med fluorescence-activated cell sorting (FACS) och odlades med olika koncentrationer av det hypoxi-inducerande ämnet Adaptaquin under 13 dagar följt av analys med flödescytometri. Resultaten visade en ökning i avseende på proliferationen hos behandlade celler där det högsta genomsnittliga totala antalet levande celler behandlade med 100 nM Adaptaquin som var 4,70 ± 1,12 x 105 celler jämfört med kontrollen som hade 2,39 ± 0,76 x 105 celler. HSC-frekvensen var högst i kontrollproverna med ett genomsnitt på 1,91 ± 0,42 % jämfört med proverna behandlade med 5 mM Adaptaquin som hade den högsta genomsnittliga HSC-frekvensen som låg på 1,52 ± 0,82 %. Den största synliga skillnaden mellan kontroll- och behandlingsprover var synlig när det observerade totala antalet celler jämfördes mellan behandlade prover som i genomsnitt hade fler totala celler. Skillnaden i proliferation var å andra sidan för liten för att se en signifikant skillnad mellan proverna. Slutsatsen är att Adaptaquin inte hade någon signifikant påverkan på att hålla HSCs odifferentierade men kan ha potential att användas som ett komplement till andra faktorer för att odla HSCs in vitro och efterlikna dess hypoxiska biologiska miljö.

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