Thesis (Ph. D.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Vita. "August 2007" Includes bibliographical references.

Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / O Trypanosoma cruzi é o agente etiológico da doença de Chagas, transmitida através de insetos vetores triatomíneos durante a alimentação no hospedeiro vertebrado. Os triatomíneos ingerem numa única alimentação cerca de 10 mM de heme ligado à hemoglobina. O heme é uma importante molécula no metabolismo dos organismos. Um mecanismo intracelular importante no controle de sua homeostase é a degradação enzimática pela Heme Oxigenase (HO) formando biliverdina (Bv), monóxido de carbono e ferro. Como esta enzima não está presente no genoma de T. cruzi, esse trabalho tem por objetivo identificar uma atividade funcional de HO neste parasito, uma vez que dados do nosso laboratório mostram a presença de biliverdina nas incubações dessas células com heme. No presente trabalho testamos o efeito do SnPPIX (inibidor da HO-1), CoPPIX (indutor da HO-1) e Bv sobre a proliferação da forma epimastigota do parasito. A adição de SnPPIX diminuiu a proliferação do parasito na tanto na ausência quanto na presença de heme. Quando a Bv foi adicionada à cultura esse efeito foi revertido; a Bv aumenta a proliferação celular na presença de heme. Por outro lado, a adição de CoPPIX não interferiu na proliferação. Posteriormente, mostramos através da técnica de immunoblotting, utilizando anticorpo monoclonal contra a HO-1, um aumento da expressão de uma proteína em resposta ao heme. Diferentemente das HO-1 já descritas que possuem massa molecular de 32 kDa, a única banda reconhecida pelo anticorpo apresenta 45 kDa. Analisamos também a expressão da HO-1 na presença de CoPPIX, SnPPIX e biliverdina, e somente o CoPPIX foi capaz de modular os níveis de expressão da HO-1. A análise estrutural através da técnica de imunocitoquímica mostrou uma maior expressão da enzima na presença de heme, e que a HO-1 de T. cruzi pode ter mais de uma localização, apresentando marcação citoplasmática e glicossomal. A fim de investigar a sequência da HO-1 de T. cruzi, o DNA genômico foi extraído para amplificação por PCR do gene da HO-1 utilizando oligonucleotídeos desenhados no genoma de T. cruzi. Os dois pares de oligonucleotídeos utilizados nao foram capazes de amplificar uma sequência equivalente a uma HO. Em seguida, utilizamos a técnica de imunoprecipitação, seguida de immunoblotting, com anticorpo anti-HO-1, com objetivo de concentrar a proteína alvo, e observamos um aumento significativo do imunocomplexo nas células tratadas com heme 300 mM, cerca de 2 vezes em relação ao controle. Dando seguimento à tentativa de identificação da HO-1 de T. cruzi, utilizamos a técnica de espectrometria de massa a partir de eletroforese unidimensional, que mostrou uma grande alteração do perfil protéico na presença de heme, mas futuros experimentos são necessários, como eletroforese 2D, para a identificação da proteína alvo / Trypanosoma cruzi, the ethiologic agent of Chagas disease, is transmitted through triatomine vectors during their blood-meal on vertebrate host. These hematophagous insects ingest blood about 6 to 12 times its original weight, reaching in a single meal about 10 mM heme bound to hemoglobin. Heme (iron protoporphyrin IX) is an important molecule in metabolism of all living organisms. One important intracellular mechanism to control heme homeostasis is its enzymatic degradation by heme oxygenase (HO). HO catalyzes the degradation of heme to biliverdin (Bv), carbon monoxide and iron. HO is absent in T. cruzi genome, thus we have been investigating the presence of a functional HO in this parasite, since our previous results showed a presence of biliverdin in heme-treated epimastigotes. In the present work, we evaluated the effect of SnPPIX, a HO-1 inhibitor, CoPPIX, a HO inducer, and Bv upon T. cruzi epimastigotes proliferation. The addition of SnPPIX decreased the parasite proliferation in the absence or in the presence of heme. When Bv was added to the culture this effect was reversed; Bv increases the parasite proliferation in the presence of heme. On the other hand, CoPPIX did not interfered on proliferation. Furthermore, we showed through immunoblotting, using an anti-HO-1 monoclonal antibody, an increase in the protein expression in heme-treated epimastigotes. Differently of described HO-1 that has a mass molecular of a 32 kDa, we showed a 45 kDa protein, the only band recognize by the HO-1 antibody. HO-1 expression analysis in the presence of CoPPIX, SnPPIX and biliverdin, showed that only CoPPIX was able to modulate its expression level. Ultrastructural immunocytochemistry analysis suggests a higher expression of the enzyme in heme-treated epimastigotes, and that T. cruzi HO-1 might have a dual distribution, since the anti-HO-1 antibody labeled both cytosol and glycosomes. In order to investigate the T. cruzi HO-1 gene sequence, we isolated genomic DNA from T. cruzi for PCR amplification using primers designed as from the parasite genome. Unfortunately, the two pairs of the designed oligonucleotides tested were unable to amplify a sequence equivalent to a HO-1. In order to isolate the target protein, immunoprecipitation was performed and subsequently immunoblotted with anti-HO-1 antibody. The immunocomplex level was two-fold higher in heme-treated cells. Following the attempt to identify a HO-1 in T. cruzi, we used mass spectrometry from unidimensional electrophoresis. We showed a significant protein profile modification in heme-treated epimastigotes, but further experiments will be necessary, such as mass spectrometry from bidimensional electrophoresis, for identification of the target protein

Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / O Trypanosoma cruzi é o agente etiológico da doença de Chagas, transmitida através de insetos vetores triatomíneos durante a alimentação no hospedeiro vertebrado. Os triatomíneos ingerem numa única alimentação cerca de 10 mM de heme ligado à hemoglobina. O heme é uma importante molécula no metabolismo dos organismos. Um mecanismo intracelular importante no controle de sua homeostase é a degradação enzimática pela Heme Oxigenase (HO) formando biliverdina (Bv), monóxido de carbono e ferro. Como esta enzima não está presente no genoma de T. cruzi, esse trabalho tem por objetivo identificar uma atividade funcional de HO neste parasito, uma vez que dados do nosso laboratório mostram a presença de biliverdina nas incubações dessas células com heme. No presente trabalho testamos o efeito do SnPPIX (inibidor da HO-1), CoPPIX (indutor da HO-1) e Bv sobre a proliferação da forma epimastigota do parasito. A adição de SnPPIX diminuiu a proliferação do parasito na tanto na ausência quanto na presença de heme. Quando a Bv foi adicionada à cultura esse efeito foi revertido; a Bv aumenta a proliferação celular na presença de heme. Por outro lado, a adição de CoPPIX não interferiu na proliferação. Posteriormente, mostramos através da técnica de immunoblotting, utilizando anticorpo monoclonal contra a HO-1, um aumento da expressão de uma proteína em resposta ao heme. Diferentemente das HO-1 já descritas que possuem massa molecular de 32 kDa, a única banda reconhecida pelo anticorpo apresenta 45 kDa. Analisamos também a expressão da HO-1 na presença de CoPPIX, SnPPIX e biliverdina, e somente o CoPPIX foi capaz de modular os níveis de expressão da HO-1. A análise estrutural através da técnica de imunocitoquímica mostrou uma maior expressão da enzima na presença de heme, e que a HO-1 de T. cruzi pode ter mais de uma localização, apresentando marcação citoplasmática e glicossomal. A fim de investigar a sequência da HO-1 de T. cruzi, o DNA genômico foi extraído para amplificação por PCR do gene da HO-1 utilizando oligonucleotídeos desenhados no genoma de T. cruzi. Os dois pares de oligonucleotídeos utilizados nao foram capazes de amplificar uma sequência equivalente a uma HO. Em seguida, utilizamos a técnica de imunoprecipitação, seguida de immunoblotting, com anticorpo anti-HO-1, com objetivo de concentrar a proteína alvo, e observamos um aumento significativo do imunocomplexo nas células tratadas com heme 300 mM, cerca de 2 vezes em relação ao controle. Dando seguimento à tentativa de identificação da HO-1 de T. cruzi, utilizamos a técnica de espectrometria de massa a partir de eletroforese unidimensional, que mostrou uma grande alteração do perfil protéico na presença de heme, mas futuros experimentos são necessários, como eletroforese 2D, para a identificação da proteína alvo / Trypanosoma cruzi, the ethiologic agent of Chagas disease, is transmitted through triatomine vectors during their blood-meal on vertebrate host. These hematophagous insects ingest blood about 6 to 12 times its original weight, reaching in a single meal about 10 mM heme bound to hemoglobin. Heme (iron protoporphyrin IX) is an important molecule in metabolism of all living organisms. One important intracellular mechanism to control heme homeostasis is its enzymatic degradation by heme oxygenase (HO). HO catalyzes the degradation of heme to biliverdin (Bv), carbon monoxide and iron. HO is absent in T. cruzi genome, thus we have been investigating the presence of a functional HO in this parasite, since our previous results showed a presence of biliverdin in heme-treated epimastigotes. In the present work, we evaluated the effect of SnPPIX, a HO-1 inhibitor, CoPPIX, a HO inducer, and Bv upon T. cruzi epimastigotes proliferation. The addition of SnPPIX decreased the parasite proliferation in the absence or in the presence of heme. When Bv was added to the culture this effect was reversed; Bv increases the parasite proliferation in the presence of heme. On the other hand, CoPPIX did not interfered on proliferation. Furthermore, we showed through immunoblotting, using an anti-HO-1 monoclonal antibody, an increase in the protein expression in heme-treated epimastigotes. Differently of described HO-1 that has a mass molecular of a 32 kDa, we showed a 45 kDa protein, the only band recognize by the HO-1 antibody. HO-1 expression analysis in the presence of CoPPIX, SnPPIX and biliverdin, showed that only CoPPIX was able to modulate its expression level. Ultrastructural immunocytochemistry analysis suggests a higher expression of the enzyme in heme-treated epimastigotes, and that T. cruzi HO-1 might have a dual distribution, since the anti-HO-1 antibody labeled both cytosol and glycosomes. In order to investigate the T. cruzi HO-1 gene sequence, we isolated genomic DNA from T. cruzi for PCR amplification using primers designed as from the parasite genome. Unfortunately, the two pairs of the designed oligonucleotides tested were unable to amplify a sequence equivalent to a HO-1. In order to isolate the target protein, immunoprecipitation was performed and subsequently immunoblotted with anti-HO-1 antibody. The immunocomplex level was two-fold higher in heme-treated cells. Following the attempt to identify a HO-1 in T. cruzi, we used mass spectrometry from unidimensional electrophoresis. We showed a significant protein profile modification in heme-treated epimastigotes, but further experiments will be necessary, such as mass spectrometry from bidimensional electrophoresis, for identification of the target protein

Type 1 diabetes (T1D) is an autoimmune disease whereby the insulin-producing β-cells of the pancreas are destroyed by the immune system, possibly related to an inappropriate immune reaction to dietary antigens and/or microbes in the gut. We previously observed a deficit in gut-resident CD163+ M2 anti-inflammatory macrophages in BioBreeding diabetes-prone (BBdp) rats. Heme oxygenase-1 (HO-1) is the rate-limiting enzyme of the CD163 pathway and through the breakdown of toxic heme releases potent antioxidants. We hypothesized that the treatment of animals with cobalt protoporphyrin (CoPP), an inducer of HO-1 expression, would inhibit development of T1D through modulation of the CD163/HO-1 pathway and increase M2 macrophages. HO-1 expression was significantly increased in the pancreas and gut. T1D incidence was inhibited in CoPP-treated rats and these animals showed an unexpected increase in cells expressing CD68 (an M1 pro-inflammatory macrophage marker) in the pancreas and gut. CoPP induced the expression of cathelicidin anti-microbial peptide (CAMP) in the jejunum, which co-localized with CD163+ (M2) macrophages. KLF4, an M2 macrophage-specific transcription factor, was significantly upregulated in the pancreas and jejunum of CoPP-treated animals and co-localized with CD68 and HO-1 in the pancreas. We conclude that HO-1 induction prevented T1D through modulation of the gut immune system and potential recruitment of a unique population of anti-inflammatory M2 macrophages in the gut and pancreas

Acute kidney injury (AKI) is a major public health concern, which contributes to serious hospital complications, chronic kidney disease (CKD) and even death. Renal ischemia- reperfusion injury (IRI) remains a leading cause of AKI.IRI combines major cell stress, significant burst of free radicals, and strong inflammatory responses leading to extensive cell injury, necrosis, and late interstitial fibrosis. Moreover, IRI- induced AKI releases pro-inflammatory cytokines (e.g. IL-1β, TNF-α, IL-6) that induce a systemic inflammatory response, resulting in pro-inflammatory cells recruitment and remote organ damage. AKI is associated with poor outcomes, particularly when extrarenal complications or distant organ injuries occur.The stress-responsive enzyme, heme oxygenase-1 (HO-1) mediates protection against renal IRI and may be preventively induced using hemin prior to renal insult. This HO-1 induction pathway called hemin preconditioning is largely known in the literature to be effective.We first confirmed that hemin-induced HO-1 improved renal outcomes after IRI (i.e. fewer renal damage, renal inflammation and oxidative stress). We then demonstrated that this protective pathway mitigated AKI-induced ALI, a major extrarenal complication after renal IRI, through modulation of systemic and lung inflammation.Afterwards, we focused on the specific contribution of myeloid HO-1 to renal IRI, which remains poorly characterized. We therefore investigated the contribution of myeloid HO-1 to renal IRI using mice with myeloid-restricted deletion of HO-1 (HO-1M-KO). We observed that myeloid HO-1 appeared to be a critical regulator of the earliest phases of IRI (i.e. higher plasma creatinine, tubular damage, and renal inflammation/oxidative stress in HO-1M-KO mice).As a link between the severity of renal injury and the risk maladaptive repair leading to CKD has been established, we thereby decided to focus on tubular repair and fibrosis deposition upon IRI. We identified that myeloid HO-1 prevented maladaptive repair and subsequent CKD through modulation of cell-cycle and autophagy regulatory proteins.We then showed that hemin-mediated protection requires specific expression of HO-1 within myeloid cells. We therefore identified CD11b+ F4/80lo macrophages as the main protective myeloid source of HO-1 upon renal IRI. Interestingly, we observed this myeloid cell sub- population in the kidney and spleen, suggesting that protective effects might be provided by both tissue-resident and infiltrating/circulating HO-1+ myeloid cells.Based on its promising cytoprotective effects when giving preemptively, we investigated the use of hemin-induced myeloid HO-1 as a strategy to mitigate established AKI. However, due to its chemical structure and oxidative properties, hemin worsened IRI-induced AKI. We thereby identified that hemin had a dual effect on renal IRI, protective or deleterious, depending on the timing of its administration.Altogether, this work suggests that myeloid HO-1 plays a critical role in the modulation of IRI- induced AKI by improving short- and long-term functional outcomes after renal IRI. We conclude that hemin-induced myeloid HO-1 pathway might be an efficient preventive strategy in many renal IRI situations with predictable AKI such as renal transplantation or partial nephrectomy. / Doctorat en Sciences médicales (Médecine) / info:eu-repo/semantics/nonPublished

No description available.

A malária é uma doença causada pelo parasita do gênero Plasmodium e que foi responsável por cerca de 440.000 mortes em 2015. A síndrome do desconforto respiratório agudo (SDRA) é uma das principais complicações clínicas da malária. O modelo murino DBA/2 reproduz os sinais clínicos da SDRA observados em humanos, quando infectado com o Plasmodium berghei ANKA. Além disso, altos níveis da enzima heme oxigenase 1 (HO-1) foram observados em casos de malária cerebral e em SDRA em humanos. Os nossos dados indicam que os níveis da HO-1 estão aumentados em camundongos que desenvolvem SDRA associada à malária (SDRA-AM). Adicionalmente, a droga indutora de HO-1 (hemina) aumentou a sobrevivência e preveniu a SDRA-AM. Verificou-se também uma redução na permeabilidade pulmonar e nos níveis de VEGF, além de uma melhoria nos parâmetros respiratórios em animais tratados com hemina. Assim sendo, a indução da HO-1 antes do desenvolvimento da SDRA-AM é protetora e assim, a HO-1 pode ser um alvo de novos fármacos, como forma de prevenir o desenvolvimento da SDRA-AM em humanos. / Malaria is a serious disease, caused by the parasite of the genus Plasmodium, which was responsible to 440,000 deaths in 2015. Acute lung injury/ acute respiratory distress syndrome (ALI/ARDS) is one of the main clinical complications in severe malaria. The murine model DBA/2 reproduces the clinical signs of ALI/ARDS observed in humans, when infected with Plasmodium berghei ANKA. Additionally, high levels heme oxygenase 1 (HO-1) were reported in cases of cerebral malaria and in ALI/ARDS in humans. Our data have indicated that the HO-1 levels are increased in mice that develop malaria associated ALI/ARDS (MA-ALI/ARDS). Additionally, a HO-1 inducing drug (hemin) increased the survival rate and prevented mice from developing MA-ALI/ARDS in treated mice. Also, there was a decrease in the lung permeability and in lung VEGF levels, and an amelioration of respiratory parameters. Therefore, the induction of HO-1 before the development of MA-ALI/ARDS is protective, making this enzyme a possible target of new drugs to prevent the development of MA-ALI/ARDS in humans.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / As lectinas de algas marinhas possuem vÃrias aplicaÃÃes farmacolÃgicas. O objetivo deste trabalho foi caracterizar parcialmente a estrutura e avaliar os efeitos em modelos clÃssicos de inflamaÃÃo da lectina da alga marinha verde Caulerpa cupressoides. A lectina de Caulerpa cupressoides (LCc) foi extraÃda com tampÃo Tris-HCl 25 mM, pH 7,5 e isolada por cromatografia de troca iÃnica em coluna de DEAE-celulose. A caracterizaÃÃo estrutural parcial apresentou uma sequÃncia aminoterminal com 31 resÃduos de aminoÃcidos, obtida de acordo com o mÃtodo de degradaÃÃo de Edman, enquanto que na espectroscopia de ressonÃncia magnÃtica nuclear unidimensional 1H para a LCc purificada por Sephadex G-100 e obtida por DEAE-celulose, foi demostrado uma similaridade entre os sinais obtidos em ambos os espectros. A atividade anti-inflamatÃria foi avaliada em ratos Wistar machos (n=6), utilizando o modelo de edema de pata induzidos por carragenana (700 μg/pata), dextrana (500 μg/pata), histamina (100 μg/pata), serotonina (20 μg/pata) ou bradicinina (30 μg/pata). Grupos de animais foram submetidos ao tratamento com LCc (0,1; 1,0 ou 10,0 mg/kg; i.v.), 30 min antes do estÃmulo inflamatÃrio. Foi avaliado o envolvimento da LCc (1,0 mg/kg) na via da Heme oxigenase-1. Foram utilizados grupos que receberam tratamento com LCc ligada ao inibidor mucina (8,0 mg/kg; i.v.) ou somente mucina (8,0 mg/kg; i.v.) e dexametasona (1,0 mg/kg; s.c.) foram utilizados como controles. O efeito edematogÃnico de LCc foi avaliado aplicando as doses de 0,1; 1,0 ou 10 mg/kg (i.pl.). No ensaio de edema de pata induzido por carragenana, LCc reduziu a formaÃÃo de edema sendo confirmado pela determinaÃÃo dos nÃveis teciduais de mieloperoxidase. A LCc (1,0 mg/kg) ligada a mucina nÃo apresentou efeito anti-inflamatÃrio no edema de pata induzido por carragenana, exceto na primeira hora apÃs o estÃmulo. No edema induzido por dextrana, LCc tambÃm inibiu o edema osmÃtico. Apenas a dose de 1,0 mg/kg foi utilizada no edema induzido por histamina reduzindo em 40% o edema no intervalo de 30 min LCc (1,0 mg/kg), entretanto, nÃo reduziu a formaÃÃo de edema induzido por serotonina ou bradicinina. AlÃm disso, na anÃlise histolÃgica do tecido subplantar, LCc (1,0 e 10,0 mg/kg) foi capaz de reduzir a migraÃÃo celular. Na presenÃa de ZnPP IX (3,0 mg/kg; s.c.), LCc perdeu sua capacidade inibir o edema induzido por carragenana, exercendo seu mecanismo de aÃÃo anti-inflamatÃrio atravÃs do envolvimento da via da HO-1. Enquanto que na imunohistoquÃmica, LCc (10 mg/kg) reduziu a expressÃo de IL-1β, porÃm ocorreu intensa marcaÃÃo das citocinas TNF-α e IL-6, alÃm da expressÃo de HO-1, nos grupos tratados com a mesma dose de LCc. Com relaÃÃo ao efeito edematogÃnico, LCc foi capaz de induzir intenso processo inflamatÃrio com efeito dose-dependente. No entanto, o edema induzido com a dose de 10 mg/kg de LCc foi foi inibido por indometacina, meclizina, pentoxifilina e dexametasona. Portanto, a LCc quando parcialmente caracterizada apresentou na sua sequÃncia aminoterminal uma identidade de 43% com a proteÃna da alga verde unicelular Chlamydomonas reinhardtii e apresentou propriedades anti- e prÃ-inflamatÃrias, sendo considerada um agente terapÃutico em potencial para estudos futuros nos processos inflamatÃrios. / Lectins seaweed have various pharmacological applications. This work was partially characterize the structure and evaluate the effects on classical models of inflammation lectin of the green seaweed Caulerpa cupressoides. The Caulerpa cupressoides lectin (CcL) was extracted with Tris-HCl 25 mM, pH 7.5 and isolated by ion exchange chromatography on DEAE-cellulose. Structural characterization showed a partial aminoterminal sequence with 31 amino acid residues, obtained according to the method of Edman degradation, while in nuclear magnetic resonance spectroscopy to the CcL 1H-NMR purified by Sephadex G-100 and DEAE-cellulose obtained by was demonstrated similarity between signals obtained in both spectra. The anti-inflammatory activity was evaluated in male Wistar rats (n = 6), using the model of paw edema induced by carrageenan (700 μg/paw), dextran (500 μg/paw), histamine (100 μg/paw), serotonin (20 μg/paw) or bradykinin (30 μg/paw). Groups of animals were treated with CcL (0.1, 1.0 or 10.0 mg/kg, i.v.) 30 min before the inflammatory stimulus. Was evaluated the involvement of CcL (1.0 mg/kg) towards heme oxygenase-1. Groups were used that were treated with inhibitor CcL linked mucin (8.0 mg/kg, i.v.) or only mucin (8.0 mg/kg, i.v.) and dexamethasone (1.0 mg/kg, s.c.) were used as controls. The effect edematogenic CcL was evaluated by applying the doses of 0.1, 1.0 or 10 mg/kg (i.pl.). In the trial of paw edema induced by carrageenan, CcL reduced edema formation was confirmed by determining tissue levels of myeloperoxidase. CcL (1.0 mg/kg) showed no mucin linked to anti-inflammatory effect on the paw edema induced by carrageenan, except in the first hour after stimulation. In dextran-induced edema, CcL also inhibited the osmotic swelling. Only the dose of 1.0 mg/kg was used in reducing histamine-induced edema by 40% the edema within 30 min CcL (1.0 mg/kg), however, did not reduce the edema induced by serotonin or bradykinin. Besides, in the histological analysis of tissue subplantar, CcL (1.0 and 10.0 mg/kg) was able to reduce cell migration. In the presence of ZnPP IX (3.0 mg/kg, s.c.), CcL has lost its ability to inhibit the carrageenan-induced edema, exerting its mechanism of action anti-inflammatory pathway through the involvement of HO-1. While in immunohistochemistry, CcL (10 mg/kg) reduced the expression of IL-1β, but intense staining occurred cytokines TNF-α and IL-6, and expression of HO-1 in the groups treated with the same dose of CcL. In relation the effect edematogenic, CcL was able to induce intense inflammatory process with dose-dependent effect. However, the induced edema at a dose of 10 mg/kg was CcL was inhibited by indomethacin, meclizine, pentoxifylline and dexamethasone. Therefore, when the CcL partially characterized presented in its aminoterminal sequence of 43% identity with the protein from unicellular green alga Chlamydomonas reinhardtii and showed anti-and pro-inflammatory therapeutic agent is considered a potential for future studies in inflammatory processes.

Die Hämoxygenase-1 (HO-1) ist das geschwindigkeitsbestimmende Enzym des Hämabbaus und ist wichtiger Regulator inflammatorischer Prozesse. Der Verlauf einer experimentellen akuten Pankreatitis (AP) konnte im Tiermodell durch HO-1 Induktion abgemildert werden. Die Aktivierung und Proliferation pankreatischer Stellatum Zellen (PSC) wird durch eine experimentelle HO-1 Induktion inhibiert und kann so möglicherweise vor der Fibrosierung des Pankreasparenchyms bei chronischer Pankreatitis (CP) schützen. Die Transkription der HO-1 wird durch einen GT-Repeat beeinflusst, der im Promoter lokalisiert ist. Diese Arbeit untersuchte, ob Varianten des GT-Repeat oder weitere genetische Varianten der HO-1 mit verschiedenen Pankreatitisformen assoziiert sind. Der GT-Repeat und der SNP rs2071746 wurden mit fluoreszensmarkierten Primern bzw. mit Schmelzkurvenanalyse bei 285 Patienten mit AP, bei 208 Patienten mit alkoholischer CP (ACP), bei 207 mit idiopathischer/hereditärer CP (ICP/HCP), 147 Patienten mit Alkoholischer Leberzirrhose (ALZ) und bei 289 Kontrollen untersucht. Bei den ACP Patienten wurde die GT-Repeat Analyse auf insgesamt 446 Patienten erhöht. Zusätzlich wurden die kodierenden HO-1 Abschnitte mittels DNA-Sequenzierung bei 145 Patienten mit ACP, 138 Patienten mit ICP/HCP, 147 Patienten mit ALZ und bei 151 Kontrollen analysiert. Das Exon 3 wurde darüber hinaus bei zusätzlichen ICP/HP Patienten und Kontrollen untersucht. Die Längenverteilungen des GT-Repeat, die Allelverteilung des SNP rs2071746 und die Verteilung der bei der DNA-Sequenzierung gefundenen synonymen und nicht synonymen Varianten waren bei allen untersuchten Gruppen nicht signifikant unterschiedlich. Obwohl die funktionellen Daten einen Einfluss von HO-1 Varianten auf die Pathogenese der verschiedenen Pankreatitis-Formen nahelegen, konnte unsere umfangreiche genetische Analyse keine Assoziation nachweisen. Genetische Varianten der HO-1 haben keinen Einfluss auf die Entwicklung einer AP, ACP, ICP/HCP und ALZ.

<p>Nitric oxide (NO) is an endogenous gaseous signaling molecule produced by three NO synthase isoforms (NOS1, 2, 3) and important in host defense. The induction of NOS2 during bacterial sepsis is critical for pathogen clearance but its sustained activation has long been associated with increased mortality secondary to multiple organ dysfunction syndrome (MODS). High levels of NO produced by NOS2 incite intrinsic cellular dysfunction, in part by damaging macromolecules through nitration and/or nitrosylation. These include mitochondrial DNA (mtDNA) and enzymes of key mitochondrial pathways required for maintenance of normal O2 utilization and energy homeostasis. However, animal studies and clinical trials inhibiting NOS2 have demonstrated pronounced organ dysfunction and increased mortality in response to live bacterial infections, confirming that NOS2 confers pro-survival benefits. Of particular interest here, the constitutive NOS1 and NOS3 have been linked to the up-regulation of nuclear genes involved in mitochondrial biogenesis but no comparable role has been described for NOS2. <italic> Therefore, I hypothesized that NOS2 is indispensible for host protection but must be tightly regulated to ensure NO levels are high enough to activate mitochondrial and other pro-survival genes, but below the threshold for cellular damage.</italic></p><p>This hypothesis was explored with two major Aims. The <italic>first Aim</italic> was to define the role of NOS2 in the activation of mitochondrial biogenesis in the heart of <italic>E. coli</italic>-treated mice. The <italic>second</italic> was to investigate the ability of NOS2 to be transcriptionally regulated by an enzyme previously shown to induce mitochondrial biogenesis, heme oxygenase-1 (HO-1). This hypothesis was tested using an <italic>in vivo</italic> model of sublethal heat-killed <italic>E. coli</italic> (<italic>HkEC</italic>) peritonitis in C57B/L6 (Wt), NOS2-/-, and TLR4-/- mice. Additionally, <italic>in vitro</italic> systems of mouse AML-12 or Hepa 1-6 cells pretreated with HO-1 activators or <italic>Hmox1</italic> shRNA prior to inflammatory challenge with lipopolysaccharide (LPS) +/- tumor necrosis factor-&alpha; (TNF-&alpha;). For the first Aim, Wt, NOS2-/-, and TLR4-/- mice were treated with (<italic>HkEC</italic> and cardiac tissue analyzed for mitochondrial function, expression of nuclear and mitochondrial proteins needed for mitochondrial biogenesis, and histological expression of NOS2 and TLR4 relative to changes in mitochondrial mass. For the second Aim, Wt mice were pretreated with hemin or carbon monoxide (CO) to activate HO-1 prior to <italic>HkEC</italic>-peritonitis. Liver tissue in these animals was evaluated at four hours for HO-1 induction, <italic>Nos2</italic> mRNA expression, cytokine profiles, and nuclear factor (NF)-&kappa;B activation. Liver cell lines were pretreated with hemin, CO-releasing molecule (CORM), or bilirubin one hour before LPS exposure and the <italic>Nos2</italic> transcriptional response evaluated at two and 24 hours. The MTT assay was used to confirm that <italic>in vitro</italic> treatments were not lethal. </p><p>These studies demonstrated that <italic>HkEC</italic> induced mtDNA damage in the heart that was repaired in Wt mice but not in NOS2-deficient mice. In KO mice, sustained mtDNA damage was associated with the reduced expression of nuclear (NRF-1, PGC-1&alpha;) and mitochondrial (Tfam, Pol-&gamma;) proteins needed for mitochondrial biogenesis. The findings thus supported that NOS2 is required for mitochondrial biogenesis in the heart during Gram-negative challenge. Evaluation of the relationship between HO-1 and NOS2 in murine liver was more complex; HO-1 activation in <italic>HkEC</italic>-treated Wt mice attenuated 4-hour <italic>Nos2</italic> gene transcription. In liver cell lines, hemin, CORM, and bilirubin were unable to suppress <italic>Nos2</italic> expression at the time of maximal induction (2 hours). <italic>Nos2</italic> was, however, suppressed by 24 hours, suggesting that the regulatory impact of HO-1 induction was not engaged early enough to reduce <italic>Nos2</italic> transcription at 2 hours. It is concluded that NOS2 induction in bacterial sepsis optimizes the expression of the mitochondrial biogenesis transcriptional program, which subsequently can also be regulated by HO-1/CO in murine liver. This provides a potential new mechanism by which immune suppression and mitochondrial repair can occur in tandem during the acute inflammatory response.</p> / Dissertation