Conselho Nacional de Desenvolvimento Científico e Tecnológico / A obesidade é uma doença crônica não transmissível, caracterizada pelo excesso de gordura corporal. Então, a gordura acumulada na região abdominal promove resistência à insulina e conseqüentemente alterações metabólicas as quais em conjunto configuram o quadro de síndrome metabólica (SM). O genótipo Pro12Pro parece estar relacionado à menor sensibilidade à insulina, desencadeando o processo fisiopatológico da SM. Então, o objetivo deste trabalho foi avaliar o efeito de uma dieta hipocalórica sobre o perfil metabólico e composição corporal de mulheres com e sem SM com genótipo Pro12Pro no gene PPAR&#947;2. O presente estudo trata-se de um ensaio clínico, onde mulheres entre 30 e 45 anos, obesas grau I, sem SM (n=23) e com SM (n=7) foram submetidas à dieta hipocalórica por 90 dias. A identificação do genótipo foi realizada por reação em cadeia da polimerase (PCR). No início e nos dias 30, 60 e 90 foram avaliados peso corporal, massa magra (MM), massa gorda (MG), componentes da SM, uricemia, insulinemia, leptinemia, adiponectinemia, os índices HOMA-IR e QUICKI. O consumo energético foi avaliado nas 12 semanas de tratamento. Foi utilizado o teste t de Student para amostras independentes foi utilizado para comparar os grupos entre si, e o modelo pareado para comparar a evolução dentro de cada grupo em relação ao início do estudo. Todas as mulheres apresentaram genótipo Pro12Pro. O grupo com SM apresentou menor HDL-c (44,43,2 vs. 56,82,4 mg/dL, p=0,013), e maior triglicerídeo (180,926,7 vs. 89,76,6mg/dL, p=0,014) e VLDL-c (36,25,3 vs. 17,91,3mg/dL, p=0,014) no início do estudo. Ambos os grupos apresentaram redução ponderal (-3,30,7% grupo sem SM e - 4,20,9% grupo com SM) e da circunferência da cintura (-2,40,5% grupo sem SM e - 5,91,4% grupo com SM) significativas. O grupo sem SM reduziu da MG progressivamente até os 90 dias (37,00,8 para 36,60,5%, p=0,02), e com isso aumentou MM (62,00,5 para 63,40,5%, p=0,01), o grupo com SM também reduziu MG ao longo do estudo (32,62,3 para 29,62,4%, p<0,01) e aumentou MM significativamente (62,21,0 para 64,31,3%). A pressão arterial sistólica reduziu no primeiro mês de tratamento no grupo sem SM (de 120,41,8 para 112,32,1 mmHg, p<0,01). No que diz respeito aos parâmetros metabólicos, o grupo sem SM mostrou redução da insulinemia (32,54,2 para 25,92,4U/mL, p=0,05) e aumento da adiponectinemia (4,70,6 para 5,10,8 ng/mL, p=0,02) aos 30 dias, do colesterol total (180,25,8 para 173,85,4 mg/dL, p=0,04), e da leptina (27,01,9 para 18,21,4 ng/mL, p<0,01) aos 60 dias, porém, houve redução do QUICKI aos 90 dias (0,390,03 para 0,350,01, p=0,01). No grupo com SM, a leptinemia reduziu aos 60 dias (20,31,9 para 14,71,1 ng/mL, p=0,01) e a adiponectinemia aos 90 dias (5,71,2 para 7,11,4 ng/mL, p<0,01), também houve remissão de 57,1% dos casos de SM. Sugerimos que, a dieta hipocalórica foi eficaz na redução do peso corporal e da MG, principalmente a localizada na região abdominal. Conseqüentemente, houve melhora considerável do perfil metabólico relacionado à obesidade no grupo sem SM, e também dos marcadores de sensibilidade à insulina e cardioprotetores relacionados à SM, além da remissão dos casos de SM. / Obesity is a non-transmissible chronic disease, characterized by excess of body fat. Then, the accumulated fat in the abdominal region promotes insulin resistance and therefore metabolic changes which together form the clustering of the metabolic syndrome (MS). Genotype Pro12Pro seems to be related to reduced insulin sensitivity, triggering the process of the MS. The objective of this study was to evaluate the effect of a low-calorie diet on metabolic profile and body composition in women with and without MS with genotype Pro12Pro on PPAR&#947;2 gene. It is a clinical trial where women between 30 and 45 years, obese class I, without MS (n = 23) and with MS (n = 7) were submitted to a hypocaloric diet for 90 days. The identification of genotype was performed by polymerase chain reaction (PCR). At the beginning and on 30, 60 and 90 days were evaluated body weight, lean body mass (LBM), body fat mass (BFM) components of MS, serum uric acid, insulin, leptin, adiponectin, the indexes HOMA-IR and QUICKI. The energy consumption was assessed at 12 weeks of treatment. The Student t test for independent samples was used for comparison between groups, and the dependent samples test to compare the evolution within each group relative to baseline. All women had Pro12Pro genotype. The MS group had lower HDL-C (44.43.2 vs. 56.82.4 mg/dL, p=0.013) and higher triglyceride (180.926.7 vs. 89.76.6 mg/dL, p=0.014) and VLDL-c (36.25.3 vs. 17.91.3 mg/dL, p=0.014) at baseline. Both groups showed significant weight reduction (-3.30.7% without MS group and -4.20.9% SM group) and waist circumference (-2.40.5% group without SM and -5.91.4% SM group). The group without MS reduced BFM progressively until 90 days (37.00.8 to 36.60.5%, p=0.02), and increased LBM (62.00.5 to 63.40.5%, p=0.01), also the group with SM reduced BFM during the study (32.62.3 to 29.62.4%, p<0.01) and increased LBM significantly (62.21.0 to 64.31.3%). systolic blood pressure (SBP) decreased in the first month of treatment in the group without MS (120.41.8 to 112.32.1 mmHg, p<0.01). With regard to metabolic parameters, the group without SM showed a reduction of serum insulin (32.54.2 to 25.92.4 U/mL, p = 0.05) and increase of serum adiponectin (4.7 0.6 to 5.10.8 ng/mL, p=0.02) at 30 days, total cholesterol (180.25.8 to 173.85.4 mg/dL, p=0.04) and HDL-c (56.82.4 to 52.22.2 mg/dL, p=0.04) and serum leptin (27.01.9 to 18.21.4 ng/mL, p< 0.01) at 60 days, although had a reduction of QUICKI to 90 days (0.390.03 to 0.350.01, p=0.01). The MS group, the serum leptin levels decreased at 60 days (20.31.9 to 14.71.1 ng/mL, p=0.01) and serum adiponectin to 90 days (5.71.2 to 7.11.4 ng/mL, p<0.01), there was also a remission of 57,1% in cases of MS. We suggest that the hypocaloric diet was efficient on reduction in body weight and BFM, mainly located in the abdominal region. Therefore, considerable improvement of metabolic profile related to obesity in the group without MS was observed, as well as improvement of markers of insulin sensitivity and cardioprotection related to SM, in addition to remission of cases of MS.

No description available.

Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro / Este trabalho teve como objetivo investigar os efeitos da telmisartana (agonista PPAR-gama parcial), losartana (puro bloqueador do receptor AT1 da angiotensina II) e rosiglitazona (agonista PPAR-gama) em modelo experimental de síndrome metabólica. Os alvos do estudo foram a pressão arterial, metabolismo de carboidratos, resistência insulínica, inflamação, tecido adiposo e fígado. Camundongos C57BL/6 (a partir de 3 meses de idade) foram alimentados com dieta padrão (SC, n = 10) ou dieta hiperlipídica rica em sal (HFHS, n = 40) por 12 semanas. Após esse tempo, os animais do grupo HFHS foram subdivididos em 4 grupos (n = 10): HFHS (sem tratamento), ROSI (HFHS tratado com rosiglitazona), TELM (HFHS tratado com telmisartana) e LOS (HFHS tratado com losartana) por 5 semanas. O grupo HFHS apresentou um significante ganho de peso e aumento da pressão arterial sistólica, hiperinsulinemia com resistência insulínica, hiperleptinemia, hipertrofia de adipócitos bem como um quadro de esteatose hepática e níveis aumentados da citocina inflamatória interleucina-6 (IL-6). Os animais tratados com telmisartana chegou ao final do experimento com massa corporal similar ao grupo SC, com reversão do quadro de resistência insulínica, com pressão arterial normal, adipócitos de tamanho normal e sem apresentar esteatose hepática. Além disso, o tratamento com telmisartana aumentou a expressão de PPAR&#947; e adiponectina no tecido adiposo epididimal. A expressão da proteína desacopladora-1 (UCP-1) no tecido adiposo branco (TAB) também foi aumentada. O tratamento com losartana diminuiu a pressão arterial para valores normais, porém com menores efeitos nos parâmetros metabólicos dos animais. O presente modelo experimental de ganho de peso e hipertensão induzidos por dieta mimetiza a síndrome metabólica humana. Neste modelo, a telmisartana aumentou a expressão de UCP-1 no TAB, preveniu o ganho de peso e melhorou a sensibilidade à insulina e a esteatose hepática dos camundongos C57BL/6, provavelmente devido à ativação PPAR-gama. / The study aimed to investigate the effects of telmisartan (a partial PPAR gamma agonist), losartan (a pure angiotensin II receptor blocker) and rosiglitazone (PPAR gamma agonist) in a mice model of metabolic syndrome (MetS). The targets of this study were blood pressure (BP), carbohydrate metabolism, insulin resistance, inflammation, white adipose tissue (WAT) and liver. Male C57BL/6 mice were studied over 17 weeks after being separated into two major groups according to diet: standard chow (SC, 10% fat, n = 10) or high-fat high-salt chow (HFHS, 60% fat, 7% salt, n = 40). In the last 5 weeks of the experiment, the HFHS group was divided into four groups (n = 10): untreated HFHS, ROSI (HFHS plus rosiglitazone), TELM (HFHS plus telmisartan), and LOS (HFHS plus losartan). The HFHS group had significantly greater body mass and BP, in addition to hyperinsulinemia with insulin resistance, hyperleptinemia, adipocyte hypertrophy and hepatic steatosis as well as increased inflammatory cytokine levels. Animals treated with telmisartan had body weights similar to the SC group, in addition to reversed insulin resistance, reduced hypertension, reduced adipocyte hypertrophy, ameliorates hepatic steatosis and decreased IL-6. Telmisartan increased PPAR&#947; and adiponectin expression in white adipose tissue. Interestingly, the expression of UCP-1 in white adipose tissue was also increased by treatment with telmisartan. Losartan decreased BP but had smaller effects on metabolic parameters. The present model of diet-induced weight gain and hypertension in mice mimics human features of MetS. In this model, telmisartan enhances UCP-1 expression in WAT, prevented weight gain and ameliorates insulin sensitivity and hepatic steatosis in C57Bl/6 mice, probably due to PPAR gamma activation.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / A obesidade é uma doença crônica não transmissível, caracterizada pelo excesso de gordura corporal. Então, a gordura acumulada na região abdominal promove resistência à insulina e conseqüentemente alterações metabólicas as quais em conjunto configuram o quadro de síndrome metabólica (SM). O genótipo Pro12Pro parece estar relacionado à menor sensibilidade à insulina, desencadeando o processo fisiopatológico da SM. Então, o objetivo deste trabalho foi avaliar o efeito de uma dieta hipocalórica sobre o perfil metabólico e composição corporal de mulheres com e sem SM com genótipo Pro12Pro no gene PPAR&#947;2. O presente estudo trata-se de um ensaio clínico, onde mulheres entre 30 e 45 anos, obesas grau I, sem SM (n=23) e com SM (n=7) foram submetidas à dieta hipocalórica por 90 dias. A identificação do genótipo foi realizada por reação em cadeia da polimerase (PCR). No início e nos dias 30, 60 e 90 foram avaliados peso corporal, massa magra (MM), massa gorda (MG), componentes da SM, uricemia, insulinemia, leptinemia, adiponectinemia, os índices HOMA-IR e QUICKI. O consumo energético foi avaliado nas 12 semanas de tratamento. Foi utilizado o teste t de Student para amostras independentes foi utilizado para comparar os grupos entre si, e o modelo pareado para comparar a evolução dentro de cada grupo em relação ao início do estudo. Todas as mulheres apresentaram genótipo Pro12Pro. O grupo com SM apresentou menor HDL-c (44,43,2 vs. 56,82,4 mg/dL, p=0,013), e maior triglicerídeo (180,926,7 vs. 89,76,6mg/dL, p=0,014) e VLDL-c (36,25,3 vs. 17,91,3mg/dL, p=0,014) no início do estudo. Ambos os grupos apresentaram redução ponderal (-3,30,7% grupo sem SM e - 4,20,9% grupo com SM) e da circunferência da cintura (-2,40,5% grupo sem SM e - 5,91,4% grupo com SM) significativas. O grupo sem SM reduziu da MG progressivamente até os 90 dias (37,00,8 para 36,60,5%, p=0,02), e com isso aumentou MM (62,00,5 para 63,40,5%, p=0,01), o grupo com SM também reduziu MG ao longo do estudo (32,62,3 para 29,62,4%, p<0,01) e aumentou MM significativamente (62,21,0 para 64,31,3%). A pressão arterial sistólica reduziu no primeiro mês de tratamento no grupo sem SM (de 120,41,8 para 112,32,1 mmHg, p<0,01). No que diz respeito aos parâmetros metabólicos, o grupo sem SM mostrou redução da insulinemia (32,54,2 para 25,92,4U/mL, p=0,05) e aumento da adiponectinemia (4,70,6 para 5,10,8 ng/mL, p=0,02) aos 30 dias, do colesterol total (180,25,8 para 173,85,4 mg/dL, p=0,04), e da leptina (27,01,9 para 18,21,4 ng/mL, p<0,01) aos 60 dias, porém, houve redução do QUICKI aos 90 dias (0,390,03 para 0,350,01, p=0,01). No grupo com SM, a leptinemia reduziu aos 60 dias (20,31,9 para 14,71,1 ng/mL, p=0,01) e a adiponectinemia aos 90 dias (5,71,2 para 7,11,4 ng/mL, p<0,01), também houve remissão de 57,1% dos casos de SM. Sugerimos que, a dieta hipocalórica foi eficaz na redução do peso corporal e da MG, principalmente a localizada na região abdominal. Conseqüentemente, houve melhora considerável do perfil metabólico relacionado à obesidade no grupo sem SM, e também dos marcadores de sensibilidade à insulina e cardioprotetores relacionados à SM, além da remissão dos casos de SM. / Obesity is a non-transmissible chronic disease, characterized by excess of body fat. Then, the accumulated fat in the abdominal region promotes insulin resistance and therefore metabolic changes which together form the clustering of the metabolic syndrome (MS). Genotype Pro12Pro seems to be related to reduced insulin sensitivity, triggering the process of the MS. The objective of this study was to evaluate the effect of a low-calorie diet on metabolic profile and body composition in women with and without MS with genotype Pro12Pro on PPAR&#947;2 gene. It is a clinical trial where women between 30 and 45 years, obese class I, without MS (n = 23) and with MS (n = 7) were submitted to a hypocaloric diet for 90 days. The identification of genotype was performed by polymerase chain reaction (PCR). At the beginning and on 30, 60 and 90 days were evaluated body weight, lean body mass (LBM), body fat mass (BFM) components of MS, serum uric acid, insulin, leptin, adiponectin, the indexes HOMA-IR and QUICKI. The energy consumption was assessed at 12 weeks of treatment. The Student t test for independent samples was used for comparison between groups, and the dependent samples test to compare the evolution within each group relative to baseline. All women had Pro12Pro genotype. The MS group had lower HDL-C (44.43.2 vs. 56.82.4 mg/dL, p=0.013) and higher triglyceride (180.926.7 vs. 89.76.6 mg/dL, p=0.014) and VLDL-c (36.25.3 vs. 17.91.3 mg/dL, p=0.014) at baseline. Both groups showed significant weight reduction (-3.30.7% without MS group and -4.20.9% SM group) and waist circumference (-2.40.5% group without SM and -5.91.4% SM group). The group without MS reduced BFM progressively until 90 days (37.00.8 to 36.60.5%, p=0.02), and increased LBM (62.00.5 to 63.40.5%, p=0.01), also the group with SM reduced BFM during the study (32.62.3 to 29.62.4%, p<0.01) and increased LBM significantly (62.21.0 to 64.31.3%). systolic blood pressure (SBP) decreased in the first month of treatment in the group without MS (120.41.8 to 112.32.1 mmHg, p<0.01). With regard to metabolic parameters, the group without SM showed a reduction of serum insulin (32.54.2 to 25.92.4 U/mL, p = 0.05) and increase of serum adiponectin (4.7 0.6 to 5.10.8 ng/mL, p=0.02) at 30 days, total cholesterol (180.25.8 to 173.85.4 mg/dL, p=0.04) and HDL-c (56.82.4 to 52.22.2 mg/dL, p=0.04) and serum leptin (27.01.9 to 18.21.4 ng/mL, p< 0.01) at 60 days, although had a reduction of QUICKI to 90 days (0.390.03 to 0.350.01, p=0.01). The MS group, the serum leptin levels decreased at 60 days (20.31.9 to 14.71.1 ng/mL, p=0.01) and serum adiponectin to 90 days (5.71.2 to 7.11.4 ng/mL, p<0.01), there was also a remission of 57,1% in cases of MS. We suggest that the hypocaloric diet was efficient on reduction in body weight and BFM, mainly located in the abdominal region. Therefore, considerable improvement of metabolic profile related to obesity in the group without MS was observed, as well as improvement of markers of insulin sensitivity and cardioprotection related to SM, in addition to remission of cases of MS.

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Orientador: Munir Salomão Skaf / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-17T03:48:48Z (GMT). No. of bitstreams: 1 Silveira_RodrigoLeandro_M.pdf: 13554093 bytes, checksum: 1eb767e5bca2a60380f38f58f585e5fd (MD5) Previous issue date: 2010 / Resumo: O Receptor Ativado de Proliferadores de Peroxissomos Isoforma g (PPARg ) é uma proteína pertencente à superfamília dos Receptores Nucleares. Através da ligação de pequenas moléculas, o PPARg controla a transcrição de genes ligados à diferenciação de adipócitos e ao metabolismo de glicose e de lipídeos. O PPARg tem uma enorme cavidade de ligação que permite a ligação de várias moléculas estruturalmente distintas que geram respostas fisiológicas também distintas. O PPARg é o receptor de uma classe de drogas antidiabéticas cujo principal representante é a rosiglitazona. Além disso, diversos ligantes naturais ativam o receptor e, recentemente, foi descoberto que ácidos graxos de cadeia média podem se ligar e ativar o PPARg . A estrutura cristalográfica do PPARg na presença de ácido nonanóico mostrou que havia 3 ligantes simultaneamente ligados ao receptor. Neste trabalho, utilizamos simulações de dinâmica molecular para investigar a dinâmica do PPARg ligado à rosiglitazona e aos ácidos nonanóico, cáprico e láurico. Observamos que a rosiglitazona não ocupa todo o sítio de ligação, havendo uma complementaridade entre o ligante e o receptor na base do domínio de ligação. Os ácidos graxos, por outro lado, ocupam quase 100% da cavidade de ligação. Vimos que moléculas de água dentro do sítio são essenciais para a ligação dos ácidos graxos. A capacidade de ativação dos diferentes áacidos graxos foi correlacionada à capacidade dos mesmos manter ligação de hidrogênio com o resíduo Y473, localizado na hélice 12, a qual deve ser estabilizada para ativar o receptor. Além disso, simulações de complexos formados pela ligação simultânea da rosiglitazona e de um ácido nonanóico sugeriram que o receptor pode comportar diferentes ligantes simultaneamente. Por m, utilizamos uma técnica especial de dinâmica molecular para investigar as possíveis rotas de dissociação dos ácidos graxos do receptor. Observamos que existe um caminho preferencial para a dissociação dos ligantes e que as principais flutuações estruturais da proteína envolvidas no processo ocorrem na hélice 3 do PPARg / Abstract: The Peroxisome Proliferator-Activated Receptor Isoform (PPAR ) is a protein belonging to the Nuclear Receptors superfamily. PPAR controls the transcription of genes related to adipocyte di erentiation and lipid and glucose metabolism. PPAR has a large ligand-binding pocket that allows the binding of many molecules with uncorrelated structure that generate distinct physiologic responses. PPAR is the receptor of a class of antidiabetic drugs whose the main representant is rosiglitazone. Moreover, several natural ligands activate the receptor and, recently, it was discovered that medium chain fatty acids can bind and activate PPAR . The crystallographic structure of the complex formed by PPAR and nonanoic acid showed 3 ligands simultaneously binded to the receptor. In this work, we performed molecular dynamics simulations to investigate the dynamics of PPAR in the presence of rosiglitazone and nonanoic, capric and lauric acids. We observed that rosiglitazone does not occupy the whole binding pocket and there is a complementarity between ligand and receptor. The fatty acids, on the other hand, occupy almost 100% of the binding pocket. We saw that some water molecules within the binding pocket are essential to the binding of the fatty acids. The activation capacity of the di erent fatty acids were correlated to the capacity to keep hydrogen bond with the residue Y473 of helix 12, which must be stabilized in order to activate the transcription. Furthermore, some simulations of the complex formed by simultaneus binding of rosiglitazone and nonanoic acid suggested that the receptor can bear di erent ligands simultaneously. Finally, we used a special technique of molecular dynamics to investigate the possible dissociation paths of the nonanoic acids from the receptor. The simulations suggest that there is a preferential path to the dissociation of the ligands and the main structural uctuations involved in the process take place in the helix 3 of the receptor / Mestrado / Físico-Química / Mestre em Química

Peroxisome proliferator-activated receptors (PPARs) are nuclear receptors that function as ligand activated transcription factors. There are three identified isotypes: PPAR alpha, PPAR gamma and PPAR delta, together controlling the expression of genes involved in inflammation, cell differentiation, proliferation, lipid and carbohydrate metabolism and energy homeostasis. The PPARs are potential targets for the treatment of dyslipidaemia, type II diabetes mellitus and the metabolic syndrome. This thesis uses a multi-platform metabolomics approach, 13C-isotope substrate flux analysis, respirometry and transcriptomics to determine the role PPAR delta and PPAR gamma play in metabolic control both in adipose tissue and systemically. To achieve this, the metabolic phenotype of the 3T3-L1 adipocyte cell line was defined to generate a metabolically phenotyped in vitro model of adipose tissue. The importance of fatty acid alpha-oxidation in the differentiation of adipocytes was emphasised The effects of PPAR delta and PPAR gamma activation in white adipose tissue from the ob/ob mouse model of insulin resistance, and in the phenotyped 3T3-L1 adipocyte model, were investigated. PPAR delta activation was distinguished by oxidative catabolism of fatty acids and citric acid cycle intermediates. Conversely, PPAR gamma activation was identified by the sequestration of lipids into adipose tissue. Moreover, to address the systemic influence of PPAR activation, with a focus on the Cori cycle and the interactions of the liver and skeletal muscle, the metabolic changes that occur in these tissues following PPAR delta and PPAR gamma activation in the ob/ob mouse were examined. PPAR delta activation was characterised by the mobilisation and release of triacylglycerols (TAGs) into circulation as an energy source for peripheral tissues whereas PPAR gamma activation was defined by a reduction and sequestration of circulating TAGs. This thesis has better characterised the role of the PPARs as master regulators of metabolism and emphasised their potential as therapeutic targets for metabolic diseases of global importance.

Cadmium (Cd) is present in food at low levels, particularly in crops and is also present in groundwater. Cd can also be obtained from tobacco smoking and occupational exposure. Cd is not effectively excreted from the body. The primary organ that accumulates Cd is liver. Liver is the main organ involved in metabolizing exogenous chemicals. While metabolism of chemicals causes detoxification, it can also result in liver oxidative damage. CYP2A6 (CYP2A5 in mice) is mainly expressed in the liver. CYP2A6 expression is increased in patients with alcoholic or non-alcoholic fatty liver. Alcohol feeding induced CYP2A5 in mice and alcohol-induced fatty liver disease was enhanced in CYP2A5 knockout (CYP2A5-/-) mice, suggesting a protective effect of CYP2A5 on alcoholic fatty liver disease. PPAR-alpha, a transcription factor, is a major regulator of lipid metabolism in the liver.  CYP2A5 and PPAR-alpha are suggested to work together in regulation of lipid metabolism and in protection against alcoholic fatty liver. It is also suggested that CYP2A5 along with PPAR-alpha protects against high fat diet induced metabolic syndrome. Cadmium can also induce CYP2a5 in mice. Recently it was discovered that there is a positive relation between soil heavy metals and fatty liver disease. Exposure to Cadmium leads to lipid accumulation in the liver, which can eventually lead to the development of Non-Alcoholic Fatty Liver Disease (NAFLD). In this study, the effects of CYP2A5 and PPAR-alpha on the acute cadmium-induced liver injury were tested using CYP2A5-/- mice and PPAR-alpha knockout (PPARα -/-) mice and CYP2A5 and PPAR-alpha wild-type mice. Cadmium chloride (CdCl2) was administered intraperitoneally at 5 mg/kg body weight. A control group of mice were injected saline for comparison. The mice were sacrificed after 24 hours of injection. Blood was collected to test for markers indicative of liver disease such as ALT and AST levels, triglyceride levels, and blood glucose levels. The liver was collected to examine the liver damage by biochemical assays and pathological evaluation. Both CYP2A5-/- and PPARα -/- mice exhibited less severe liver injury compared to their wild-type counterparts. These results suggest that despite the beneficial roles of both CYP2A5 and PPAR-alpha towards alcohol-induced liver injury and metabolic syndrome, they are not protective against Cd-induced liver injury.

The increasing use of plastics has elevated the risk of exposure to environmental pollutants such as plasticisers in the general population, making it necessary to understand the possible long term health consequences of the same. In this study we aim to understand how DEHP affects the gene expression in mice models and if it causes disruptions to its cellular pathways. Two datasets, GSE18564 and GSE14920 comprising of 15 and 60 samples respectively were downloaded from GEO database for analysis. Quality control checks were done using Principal Component Analysis and quantile normalisation. Differentially expressed genes were found using LIMMA model, following which only top 20 genes were selected for pathway analysis using KEGG and Gene Ontology. DEHP was found to be associated with chemical carcinogenesis, including negative regulation of extrinsic apoptotic signaling pathway and fatty acid metabolism. Furthermore, it seems likely that PPAR-alpha might play a key role in DEHP related metabolic disruption. Further studies are required to better elucidate the effect of DEHP on individual metabolic pathway implicated in this thesis.

Apoptosis, a form of genetically programmed cell death, plays a key role in regulation of cellularity of the arterial wall. During atherogenesis, improper apoptosis may cause abnormalities of arterial morphogenesis, wall structural stability, and metabolisms. It has been well established that vascular cells undergo apoptosis after uptake of oxidized low-density lipoprotein (oxLDL). Thus, an analysis of the signaling pathway of apoptotic induction by oxLDL is of value in understanding the development of atherosclerotic plaque. In order to elucidate the signaling pathway of apoptosis induced by oxLDL, we have used Chinese hamster ovary (CHO)-K1 cells treated with a potent oxysterol, 25-hydroxycholesterol (25-OHC). In the present study, we find that oxLDL can induce apoptosis in any cell types if cells present the specific receptors on their surface to take up oxLDL, and that apoptosis-inducing activity is associated with oxysterol components in oxLDL. Oxysterol-induced apoptosis does not involve regulation of sterol regulatory element-binding protein proteolysis pathway. 25-OHC stimulates calcium uptake by CHO-K1 cells within 2 min after addition. Treatment of CHO-K1 cells with the calcium channel blocker nifedipine prevents 25-OHC induction of apoptosis. One possible signal transduction pathway initiated by calcium ion fluxes is the activation of cytosolic phospholipase A2 (cPLA2). We demonstrate that activation of cPLA2 does occur in CHO-K1 treated with 25-OHC. Activation is evidenced by 25-OHC-induced relocalization of cPLA2 to the nuclear envelope and arachidonic acid (AA) release. Loss of cPLA2 activity by treatment with a cPLA2 inhibitor results in an attenuation of AA release as well as of the apoptotic response to 25-OHC in CHO-K1 cells. CPLA2ûmediated liberation of AA leads to the formation of a cyclooxygenase product, probably a prostaglandin, which activates the transcription factor PPARγ and induces apoptosis. We also examined the execution phase of the apoptotic pathway in CHO-K1 cell death induced by 25-OHC. Oxysterol-induced apoptosis in CHO-K1 is accompanied by caspase activation and is preceded by mitochondrial cytochrome C release. Furthermore, treatment with a cPLA2 inhibitor results in an inhibition of caspase-3 activation in CHO-K1 cells. These data provide strong evidence indicating that 25-OHC induces caspase-3-mediated apoptosis via an activation of calcium-dependent cPLA2.