RESUMEN
Chronic inflammation has a pathological role in many common diseases and is influenced by both genetic and environmental factors. Here we assess the role of genetic variation in selenoprotein S (SEPS1, also called SELS or SELENOS), a gene involved in stress response in the endoplasmic reticulum and inflammation control. After resequencing SEPS1, we genotyped 13 SNPs in 522 individuals from 92 families. As inflammation biomarkers, we measured plasma levels of IL-6, IL-1beta and TNF-alpha. Bayesian quantitative trait nucleotide analysis identified associations between SEPS1 polymorphisms and all three proinflammatory cytokines. One promoter variant, -105G --> A, showed strong evidence for an association with each cytokine (multivariate P = 0.0000002). Functional analysis of this polymorphism showed that the A variant significantly impaired SEPS1 expression after exposure to endoplasmic reticulum stress agents (P = 0.00006). Furthermore, suppression of SEPS1 by short interfering RNA in macrophage cells increased the release of IL-6 and TNF-alpha. To investigate further the significance of the observed associations, we genotyped -105G --> A in 419 Mexican American individuals from 23 families for replication. This analysis confirmed a significant association with both TNF-alpha (P = 0.0049) and IL-1beta (P = 0.0101). These results provide a direct mechanistic link between SEPS1 and the production of inflammatory cytokines and suggest that SEPS1 has a role in mediating inflammation.
Asunto(s)
Variación Genética , Inflamación/genética , Proteínas de la Membrana/genética , Polimorfismo de Nucleótido Simple/genética , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Genotipo , Humanos , Mediadores de Inflamación/metabolismo , Interleucina-1/sangre , Interleucina-6/sangre , Macrófagos/citología , Macrófagos/metabolismo , Masculino , Proteínas de la Membrana/antagonistas & inhibidores , Proteínas de la Membrana/metabolismo , Persona de Mediana Edad , Regiones Promotoras Genéticas/genética , ARN Interferente Pequeño/farmacología , Selenoproteínas , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
There are epidemiological associations between obesity and type 2 diabetes, cardiovascular disease and Alzheimer's disease. The role of amyloid beta 42 (Aß42) in these diverse chronic diseases is obscure. Here we show that adipose tissue releases Aß42, which is increased from adipose tissue of male mice with obesity and is associated with higher plasma Aß42. Increasing circulating Aß42 levels in male mice without obesity has no effect on systemic glucose homeostasis but has obesity-like effects on the heart, including reduced cardiac glucose clearance and impaired cardiac function. The closely related Aß40 isoform does not have these same effects on the heart. Administration of an Aß-neutralising antibody prevents obesity-induced cardiac dysfunction and hypertrophy. Furthermore, Aß-neutralising antibody administration in established obesity prevents further deterioration of cardiac function. Multi-contrast transcriptomic analyses reveal that Aß42 impacts pathways of mitochondrial metabolism and exposure of cardiomyocytes to Aß42 inhibits mitochondrial complex I. These data reveal a role for systemic Aß42 in the development of cardiac disease in obesity and suggest that therapeutics designed for Alzheimer's disease could be effective in combating obesity-induced heart failure.
Asunto(s)
Enfermedad de Alzheimer , Diabetes Mellitus Tipo 2 , Masculino , Ratones , Animales , Péptidos beta-Amiloides , Diabetes Mellitus Tipo 2/complicaciones , Anticuerpos Neutralizantes , Obesidad/complicaciones , Glucosa , Fragmentos de PéptidosRESUMEN
Insulin resistance is a heterogeneous disorder caused by a range of genetic and environmental factors, and we hypothesize that its etiology varies considerably between individuals. This heterogeneity provides significant challenges to the development of effective therapeutic regimes for long-term management of type 2 diabetes. We describe a novel strategy, using large-scale gene expression profiling, to develop a gene expression signature (GES) that reflects the overall state of insulin resistance in cells and patients. The GES was developed from 3T3-L1 adipocytes that were made "insulin resistant" by treatment with tumor necrosis factor-α (TNF-α) and then reversed with aspirin and troglitazone ("resensitized"). The GES consisted of five genes whose expression levels best discriminated between the insulin-resistant and insulin-resensitized states. We then used this GES to screen a compound library for agents that affected the GES genes in 3T3-L1 adipocytes in a way that most closely resembled the changes seen when insulin resistance was successfully reversed with aspirin and troglitazone. This screen identified both known and new insulin-sensitizing compounds including nonsteroidal anti-inflammatory agents, ß-adrenergic antagonists, ß-lactams, and sodium channel blockers. We tested the biological relevance of this GES in participants in the San Antonio Family Heart Study (n = 1,240) and showed that patients with the lowest GES scores were more insulin resistant (according to HOMA_IR and fasting plasma insulin levels; P < 0.001). These findings show that GES technology can be used for both the discovery of insulin-sensitizing compounds and the characterization of patients into subtypes of insulin resistance according to GES scores, opening the possibility of developing a personalized medicine approach to type 2 diabetes.
Asunto(s)
Perfilación de la Expresión Génica , Resistencia a la Insulina/genética , Células 3T3-L1 , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Animales , Femenino , Regulación de la Expresión Génica/efectos de los fármacos , Transportador de Glucosa de Tipo 4/metabolismo , Humanos , Insulina/metabolismo , Masculino , Ratones , Persona de Mediana Edad , Transporte de Proteínas/efectos de los fármacos , Reproducibilidad de los Resultados , Factor de Necrosis Tumoral alfa/farmacología , Adulto JovenRESUMEN
Soluble protein hormones are key regulators of a number of metabolic processes, including food intake and insulin sensitivity. We have used a signal sequence trap to identify genes that encode secreted or membrane-bound proteins in Psammomys obesus, an animal model of obesity and type 2 diabetes (T2D). Using this signal sequence trap, we identified the chemokine chemerin as being a novel adipokine. Gene expression of chemerin and its receptor, chemokine-like receptor 1 (CMKLR1), was significantly higher in adipose tissue of obese and type 2 diabetic P. obesus compared with lean, normoglycemic P. obesus. Fractionation of P. obesus adipose tissue confirmed that chemerin was predominantly expressed in adipocytes, whereas CMKLR1 was expressed in both adipocytes and stromal-vascular cells of adipose tissue. In 3T3-L1 adipocytes, chemerin was markedly induced during differentiation, whereas CMKLR1 was down-regulated during differentiation. Serum chemerin levels were measured by ELISA in human plasma samples from 114 subjects with T2D and 142 normal glucose tolerant controls. Plasma chemerin levels were not significantly different between subjects with T2D and normal controls. However, in normal glucose tolerant subjects, plasma chemerin levels were significantly associated with body mass index, circulating triglycerides, and blood pressure. Here we report, for the first time, that chemerin is an adipokine, and circulating levels of chemerin are associated with several key aspects of metabolic syndrome.
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Quimiocinas/metabolismo , Factores Quimiotácticos/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Síndrome Metabólico/metabolismo , Obesidad/metabolismo , Receptores de Quimiocina/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Células 3T3-L1 , Adipocitos/citología , Adipocitos/metabolismo , Adipocitos/patología , Tejido Adiposo/metabolismo , Tejido Adiposo/patología , Adulto , Anciano , Animales , Presión Sanguínea , Índice de Masa Corporal , Diferenciación Celular/fisiología , Quimiocinas/sangre , Quimiocinas/genética , Factores Quimiotácticos/sangre , Factores Quimiotácticos/genética , Diabetes Mellitus Tipo 2/sangre , Diabetes Mellitus Tipo 2/patología , Regulación hacia Abajo , Expresión Génica , Gerbillinae , Humanos , Péptidos y Proteínas de Señalización Intercelular/sangre , Péptidos y Proteínas de Señalización Intercelular/genética , Mesenterio , Síndrome Metabólico/fisiopatología , Ratones , Persona de Mediana Edad , Fenotipo , Receptores de Quimiocina/genética , Receptores Acoplados a Proteínas G/genética , Tejido Subcutáneo/metabolismo , VíscerasRESUMEN
Selenium is an essential trace element and selenoprotein S is a member of the selenoprotein family that has the non-standard amino acid selenocysteine incorporated into the polypeptide. Dietary selenium has been shown to play an important protective role in a number of diseases including cancer, immune function and the male reproductive system. In this study, we have observed high levels of selenoprotein S gene expression in the testis from Psammomys obesus. Real-time PCR and immunofluorescence demonstrate that selenoprotein S expression is low in testes from 4-week-old animals but increases significantly by 8 weeks of age and remains high until 17 weeks of age. Selenoprotein S protein is detected in primary spermatocytes, Leydig and Sertoli cells of 8, 12 and 17-week-old animals. These results suggest that selenoprotein S may play a role in spermatogenesis.
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Envejecimiento/fisiología , Gerbillinae/metabolismo , Selenoproteínas/metabolismo , Espermatogénesis/fisiología , Testículo/patología , Animales , Suplementos Dietéticos , Masculino , Selenio/farmacología , Selenocisteína/metabolismo , Espermatogénesis/efectos de los fármacos , Testículo/citologíaRESUMEN
To identify genes involved in the central regulation of energy balance, we compared hypothalamic mRNA from lean and obese Psammomys obesus, a polygenic model of obesity, using differential display PCR. One mRNA transcript was observed to be elevated in obese, and obese diabetic, P. obesus compared with lean animals and was subsequently found to be increased 4-fold in the hypothalamus of lethal yellow agouti (A(y)/a) mice, a murine model of obesity and diabetes. Intracerebroventricular infusion of antisense oligonucleotide targeted to this transcript selectively suppressed its hypothalamic mRNA levels and resulted in loss of body weight in both P. obesus and Sprague Dawley rats. Reductions in body weight were mediated by profoundly reduced food intake without a concomitant reduction in metabolic rate. Yeast two-hybrid screening, and confirmation in mammalian cells by bioluminescence resonance energy transfer analysis, demonstrated that the protein it encodes interacts with endophilins, mediators of synaptic vesicle recycling and receptor endocytosis in the brain. We therefore named this transcript Src homology 3-domain growth factor receptor-bound 2-like (endophilin) interacting protein 1 (SGIP1). SGIP1 encodes a large proline-rich protein that is expressed predominantly in the brain and is highly conserved between species. Together these data suggest that SGIP1 is an important and novel member of the group of neuronal molecules required for the regulation of energy homeostasis.
Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/genética , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Metabolismo Energético/fisiología , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/metabolismo , Obesidad/fisiopatología , Animales , Peso Corporal/fisiología , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/fisiopatología , Modelos Animales de Enfermedad , Ingestión de Alimentos/fisiología , Proteína Adaptadora GRB2 , Gerbillinae , Hipotálamo/fisiología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Mutantes , Datos de Secuencia Molecular , Obesidad/genética , Ratas , Ratas Sprague-Dawley , Dominios Homologos src/fisiologíaRESUMEN
The BEACON gene (also known as UBL5) was identified as differentially expressed between lean and obese Psammomys obesus, a polygenic animal model of obesity, type 2 diabetes, and dyslipidemia. The human homologue of BEACON is located on chromosome 19p, a region likely to contain genes affecting metabolic syndrome-related quantitative traits as established by linkage studies. To assess whether the human BEACON gene may be involved in influencing these traits, we exhaustively analyzed the complete gene for genetic variation in 40 unrelated individuals and identified four variants (three novel). The two more common variants were tested for association with a number of quantitative metabolic syndrome-related traits in two large cohorts of unrelated individuals. Significant associations were found between these variants and fat mass (P = 0.026), percentage of fat (P = 0.001), and waist-to-hip ratio (P = 0.031). The same variants were also associated with total cholesterol (P = 0.024), LDL cholesterol (P = 0.019), triglycerides (P = 0.006), and postglucose load insulin levels (P = 0.018). Multivariate analysis of these correlated phenotypes also yielded a highly significant association (P = 0.0004), suggesting that BEACON may influence phenotypic variation in metabolic syndrome-related traits.
Asunto(s)
Proteínas del Ojo/genética , Síndrome Metabólico/etnología , Síndrome Metabólico/genética , Ubiquitinas/genética , Adulto , Diabetes Mellitus/etnología , Diabetes Mellitus/genética , Femenino , Frecuencia de los Genes , Predisposición Genética a la Enfermedad , Variación Genética , Humanos , Hiperlipidemias/etnología , Hiperlipidemias/genética , Masculino , Mauricio/epidemiología , Persona de Mediana Edad , Obesidad , Fenotipo , PrevalenciaRESUMEN
Here we describe a novel protein, which we have named Tanis, that is implicated in type 2 diabetes and inflammation. In Psammomys obesus, a unique polygenic animal model of type 2 diabetes and the metabolic syndrome, Tanis is expressed in the liver in inverse proportion to circulating glucose (P = 0.010) and insulin levels (P = 0.004) and in direct proportion with plasma triglyceride concentrations (P = 0.007). Hepatic Tanis gene expression was markedly increased (3.1-fold) after a 24-h fast in diabetic but not in nondiabetic P. obesus. In addition, glucose inhibited Tanis gene expression in cultured hepatocytes (P = 0.006) as well as in several other cell types (P = 0.001-0.011). Thus, Tanis seems to be regulated by glucose and is dysregulated in the diabetic state. Yeast-2 hybrid screening identified serum amyloid A (SAA), an acute-phase inflammatory response protein, as an interacting protein of Tanis, and this was confirmed by Biacore experiments. SAA and other acute-phase proteins have been the focus of recent attention as risk factors for cardiovascular disease, and we contend that Tanis and its interaction with SAA may provide a mechanistic link among type 2 diabetes, inflammation, and cardiovascular disease.
Asunto(s)
Diabetes Mellitus Tipo 2/etiología , Inflamación/etiología , Proteínas de la Membrana/fisiología , Secuencia de Aminoácidos , Animales , Apolipoproteínas/metabolismo , Secuencia de Bases , Glucemia/análisis , Mapeo Cromosómico , Cromosomas Humanos Par 15 , Exones , Expresión Génica/efectos de los fármacos , Gerbillinae , Glucosa/farmacología , Glicosilación , Humanos , Hígado/química , Hígado/metabolismo , Proteínas de la Membrana/química , Proteínas de la Membrana/genética , Datos de Secuencia Molecular , Fosforilación , Reacción en Cadena de la Polimerasa , Estructura Secundaria de Proteína , ARN Mensajero/química , Factores de Riesgo , Alineación de Secuencia , Proteína Amiloide A Sérica/metabolismoRESUMEN
OBJECTIVES: Oxysterols are hydroxylated derivatives of cholesterol detected in blood, cells, and tissues. They exhibit a number of biologic activities, including inhibition of cellular proliferation and cytotoxicity associated with induction of apoptosis. Given the important regulatory role of apoptosis in hematopoiesis, we investigated the effects of oxysterols on human hematopoietic progenitor cells (HPCs). MATERIALS AND METHODS: Colony-forming unit granulocyte-macrophage (CFU-GM) from human bone marrow and umbilical cord blood (UCB) were grown in the presence of varying concentrations of three different oxysterols-7-keto-cholesterol, 7-beta-hydroxycholesterol, and 25-hydroxycholesterol (25-OHC). Similarly, the effect of oxysterols on HL60 and CD34+ cells was investigated using annexin V staining and flow cytometry to measure apoptosis. Reduction of nitroblue tetrazolium was used to assess differentiative status of HL60 cells. RESULTS: CFU-GM derived from human bone marrow were inhibited by all three oxysterols tested, with 25-OHC being the most potent. In comparison, CFU-GM derived from UCB were less sensitive to the effects of all the oxysterols tested, with statistically significant inhibition observed only in the presence of 25-OHC. Oxysterol treatment of HL60 cells inhibited cell growth and increased the number of annexin V+ and nitroblue tetrazolium+ cells. The percentage of viable, CD34+ annexin V+ cells also was increased with oxysterol treatment of purified HPCs in liquid culture. CONCLUSIONS: These experiments indicate that oxysterol inhibition of CFU-GM and HL60 cell growth can be attributed to induction of apoptosis and/or differentiation. These investigations revealed that oxysterols are a new class of inhibitors of HPC proliferation of potential relevance in vivo and in vitro.
Asunto(s)
Células Madre Hematopoyéticas/efectos de los fármacos , Hidroxicolesteroles/farmacología , Cetocolesteroles/farmacología , Adulto , Apoptosis/efectos de los fármacos , Células Sanguíneas/citología , Células de la Médula Ósea/citología , Diferenciación Celular/efectos de los fármacos , Células Cultivadas/efectos de los fármacos , Ensayo de Unidades Formadoras de Colonias , Sangre Fetal/citología , Células HL-60/efectos de los fármacos , Humanos , Recién NacidoRESUMEN
SelS is a newly identified selenoprotein and its gene expression is up-regulated in the liver of Psammomys obesus after fasting. We have examined whether SelS is regulated by glucose deprivation and endoplasmic reticulum (ER) stress in HepG2 cells. Glucose deprivation and the ER stress inducers tunicamycin and thapsigargin increased SelS gene expression and protein content several-fold in parallel with glucose-regulated protein 78. The overexpression of SelS increased Min6 cell resistance to oxidative stress-induced toxicity. These results indicate that SelS is a novel member of the glucose-regulated protein family and its function is related to the regulation of cellular redox balance.
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Retículo Endoplásmico/fisiología , Regulación Neoplásica de la Expresión Génica , Glucosa/metabolismo , Proteínas HSP70 de Choque Térmico , Proteínas de la Membrana , Proteínas/genética , Estrés Fisiológico/metabolismo , Secuencia de Aminoácidos , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patología , Línea Celular Tumoral , Supervivencia Celular , Retículo Endoplásmico/efectos de los fármacos , Inhibidores Enzimáticos/farmacología , Genes Reporteros , Humanos , Peróxido de Hidrógeno/farmacología , Luciferasas/genética , Luciferasas/metabolismo , Datos de Secuencia Molecular , Mutagénesis Insercional , Oxidantes/farmacología , Regiones Promotoras Genéticas , Proteínas/química , Proteínas/metabolismo , ARN Mensajero/metabolismo , Selenoproteínas , Homología de Secuencia de Aminoácido , Tapsigargina/farmacología , Factores de Tiempo , Tunicamicina/farmacologíaRESUMEN
OBJECTIVES/AIM: Microarray (gene chip) technology offers a powerful new tool for analyzing the expression of large numbers of genes in many experimental samples. The aim of this study was to design, construct, and use a gene chip to measure the expression levels of key genes in metabolic pathways related to insulin resistance. METHODS: We selected genes that were implicated in the development of insulin resistance, including genes involved in insulin signaling; glucose uptake, oxidation, and storage; fat uptake, oxidation, and storage; cytoskeletal components; and transcription factors. The key regulatory genes in the pathways were identified, along with other recently identified candidate genes such as calpain-10. A total of 242 selected genes (including 32 internal control elements) were sequence-verified, purified, and arrayed on aldehyde-coated slides. RESULTS: Where more than 1 clone containing the gene of interest was available, we chose those containing the genes in the 5' orientation and an insert size of around 1.5 kb. Of the 262 clones purchased, 56 (21%) were found to contain sequences other than those expected. In addition, 2 (1%) did not grow under standard conditions and were assumed to be nonviable. In these cases, alternate clones containing the gene of interest were chosen as described above. The current version of the Insulin Resistance Gene Chip contains 210 genes of interest, plus 48 control elements. A full list of the genes is available at http://www.hbs.deakin.edu.au/mru/research/gene_chip_tech/genechip_three.htm/. CONCLUSIONS: The human Insulin Resistance Gene Chip that we have constructed will be a very useful tool for investigating variation in the expression of genes relevant to insulin resistance under various experimental conditions. Initially, the gene chip will be used in studies such as exercise interventions, fasting, euglycemic-hyperinsulinemic clamps, and administration of antidiabetic agents.
Asunto(s)
Resistencia a la Insulina/genética , Análisis de Secuencia por Matrices de Oligonucleótidos , Secuencia de Bases , Línea Celular , Cartilla de ADN , Electroforesis en Gel de Agar , Reproducibilidad de los ResultadosRESUMEN
DNA-based approaches to the discovery of genes contributing to the development of type 2 diabetes have not been very successful despite substantial investments of time and money. The multiple gene-gene and gene-environment interactions that influence the development of type 2 diabetes mean that DNA approaches are not the ideal tool for defining the etiology of this complex disease. Gene expression-based technologies may prove to be a more rewarding strategy to identify diabetes candidate genes. There are a number of RNA-based technologies available to identify genes that are differentially expressed in various tissues in type 2 diabetes. These include differential display polymerase chain reaction (ddPCR), suppression subtractive hybridization (SSH), and cDNA microarrays. The power of new technologies to detect differential gene expression is ideally suited to studies utilizing appropriate animal models of human disease. We have shown that the gene expression approach, in combination with an excellent animal model such as the Israeli sand rat (Psammomys obesus), can provide novel genes and pathways that may be important in the disease process and provide novel therapeutic approaches. This paper will describe a new gene discovery, beacon, a novel gene linked with energy intake. As the functional characterization of novel genes discovered in our laboratory using this approach continues, it is anticipated that we will soon be able to compile a definitive list of genes that are important in the development of obesity and type 2 diabetes.
Asunto(s)
Diabetes Mellitus Tipo 2/genética , Modelos Animales de Enfermedad , Obesidad/genética , Animales , Reacción en Cadena de la PolimerasaRESUMEN
We studied the effects of alcohol intake on postexercise muscle glycogen restoration with samples from vastus lateralis being collected immediately after glycogen-depleting cycling and after a set recovery period. Six well-trained cyclists undertook a study of 8-h recovery (2 meals), and another nine cyclists undertook a separate 24-h protocol (4 meals). In each study, subjects completed three trials in crossover order: control (C) diet [meals providing carbohydrate (CHO) of 1.75 g/kg]; alcohol-displacement (A) diet (1.5 g/kg alcohol displacing CHO energy from C) and alcohol + CHO (AC) diet (C + 1.5 g/kg alcohol). Alcohol intake reduced postmeal glycemia especially in A trial and 24-h study, although insulin responses were maintained. Alcohol intake increased serum triglycerides, particularly in the 24-h study and AC trial. Glycogen storage was decreased in A diets compared with C at 8 h (24.4 +/- 7 vs. 44.6 +/- 6 mmol/kg wet wt, means +/- SE, P < 0.05) and 24 h (68 +/- 5 vs. 82 +/- 5 mmol/kg wet wt, P < 0.05). There was a trend to reduced glycogen storage with AC in 8 h (36.2 +/- 8 mmol/kg wet wt, P = 0.1) but no difference in 24 h (85 +/- 9 mmol/kg wet wt). We conclude that 1). the direct effect of alcohol on postexercise glycogen synthesis is unclear, and 2). the main effect of alcohol intake is indirect, by displacing CHO intake from optimal recovery nutrition practices.
Asunto(s)
Depresores del Sistema Nervioso Central/farmacología , Etanol/farmacología , Ejercicio Físico/fisiología , Glucógeno/metabolismo , Músculo Esquelético/metabolismo , Adulto , Ciclismo/fisiología , Glucemia/metabolismo , Depresores del Sistema Nervioso Central/sangre , Estudios Cruzados , Dieta , Carbohidratos de la Dieta/farmacología , Etanol/sangre , Humanos , Insulina/sangre , Masculino , Músculo Esquelético/efectos de los fármacos , Músculo Esquelético/fisiología , Triglicéridos/sangreRESUMEN
The hypothalamus is a key central controller of energy homeostasis and is the source and/or site of action of many neuropeptides involved in this process. The aim of this study was to isolate hypothalamic genes differentially expressed between lean and obese Psammomys obesus, a polygenic animal model of obesity and type 2 diabetes. Differential display PCR was used to compare hypothalamic gene expression profiles of lean and healthy, obese and hyperinsulinemic, and obese, diabetic P. obesus in both the fed and fasted states. We conducted differential display with 180 separate primer combinations to amplify approximately 9,000 expressed transcripts. Sixty differentially expressed bands were excised. Taqman PCR was performed on 36 of these transcripts to confirm differential gene expression in a larger sample population. Of these 36 transcripts, 9 showed homology to known genes, and 27 were considered to be novel sequences. Gene expression profiles for two of these genes are presented here. In conclusion, differential display PCR was successfully used to isolate several transcripts that may be involved in the central regulation of energy balance. We are currently conducting numerous studies to further investigate the role of these genes in the development of obesity in P. obesus.
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Expresión Génica , Gerbillinae/genética , Hipotálamo/metabolismo , Obesidad/genética , Animales , Secuencia de Bases , ADN Complementario , Grasas/metabolismo , Gerbillinae/metabolismo , Masculino , Datos de Secuencia Molecular , Obesidad/metabolismo , Reacción en Cadena de la Polimerasa/métodosRESUMEN
PURPOSE: The role of v-ATPases in cancer biology is being increasingly recognized. Yeast studies indicate that the tyrosine kinase inhibitor imatinib may interact with the v-ATPase genes and alter the course of cancer progression. Data from humans in this regard are lacking. METHODS: We constructed 55 lymphoblastoid cell lines from pedigreed, cancer-free human subjects and treated them with IC20 concentration of imatinib mesylate. Using these cell lines, we (i) estimated the heritability and differential expression of 19 genes encoding several subunits of the v-ATPase protein in response to imatinib treatment; (ii) estimated the genetic similarity among these genes; and (iii) conducted a high-density scan to find cis-regulating genetic variation associated with differential expression of these genes. RESULTS: We found that the imatinib response of the genes encoding v-ATPase subunits is significantly heritable and can be clustered to identify novel drug targets in imatinib therapy. Further, five of these genes were significantly cis-regulated and together represented nearly half-log fold change in response to imatinib (p = 0.0107) that was homogenous (p = 0.2598). CONCLUSIONS: Our results proffer support to the growing view that personalized regimens using proton pump inhibitors or v-ATPase inhibitors may improve outcomes of imatinib therapy in various cancers.
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Antineoplásicos/farmacología , Benzamidas/farmacología , Piperazinas/farmacología , Pirimidinas/farmacología , ATPasas de Translocación de Protón Vacuolares/genética , Línea Celular , Humanos , Mesilato de Imatinib , Linfocitos/efectos de los fármacos , Linfocitos/enzimología , ATPasas de Translocación de Protón Vacuolares/fisiologíaRESUMEN
BACKGROUND: Imatinib mesylate is currently the drug of choice to treat chronic myeloid leukemia. However, patient resistance and cytotoxicity make secondary lines of treatment, such as omacetaxine mepesuccinate, a necessity. Given that drug cytotoxicity represents a major problem during treatment, it is essential to understand the biological pathways affected to better predict poor drug response and prioritize a treatment regime. METHODS: We conducted cell viability and gene expression assays to determine heritability and gene expression changes associated with imatinib and omacetaxine treatment of 55 non-cancerous lymphoblastoid cell lines, derived from 17 pedigrees. In total, 48,803 transcripts derived from Illumina Human WG-6 BeadChips were analyzed for each sample using SOLAR, whilst correcting for kinship structure. RESULTS: Cytotoxicity within cell lines was highly heritable following imatinib treatment (h2 = 0.60-0.73), but not omacetaxine treatment. Cell lines treated with an IC20 dose of imatinib or omacetaxine showed differential gene expression for 956 (1.96%) and 3,892 transcripts (7.97%), respectively; 395 of these (0.8%) were significantly influenced by both imatinib and omacetaxine treatment. k-means clustering and DAVID functional annotation showed expression changes in genes related to kinase binding and vacuole-related functions following imatinib treatment, whilst expression changes in genes related to cell division and apoptosis were evident following treatment with omacetaxine. The enrichment scores for these ontologies were very high (mostly >10). CONCLUSIONS: Induction of gene expression changes related to different pathways following imatinib and omacetaxine treatment suggests that the cytotoxicity of such drugs may be differentially tolerated by individuals based on their genetic background.
Asunto(s)
Regulación de la Expresión Génica/efectos de los fármacos , Harringtoninas/toxicidad , Linfocitos/efectos de los fármacos , Linfocitos/metabolismo , Piperazinas/toxicidad , Pirimidinas/toxicidad , Benzamidas , Línea Celular , Análisis por Conglomerados , Relación Dosis-Respuesta a Droga , Homoharringtonina , Humanos , Mesilato de Imatinib , Patrón de Herencia/genética , Anotación de Secuencia Molecular , Análisis de Secuencia por Matrices de Oligonucleótidos , Reproducibilidad de los ResultadosRESUMEN
The human Abelson helper integration site-1 (AHI1) gene is associated with both neurologic and hematologic disorders; however, it is also located in a chromosomal region linked to metabolic syndrome phenotypes and was identified as a type 2 diabetes mellitus susceptibility gene from a genomewide association study. To further define a possible role in type 2 diabetes mellitus development, AHI1 messenger RNA expression levels were investigated in a range of tissues and found to be highly expressed in skeletal muscle as well as displaying elevated levels in brain regions and gonad tissues. Further analysis in a rodent polygenic animal model of obesity and type 2 diabetes mellitus identified increased Ahi-1 messenger RNA levels in red gastrocnemius muscle from fasted impaired glucose-tolerant and diabetic rodents compared with healthy animals (P < .002). Moreover, elevated gene expression levels were confirmed in skeletal muscle from fasted obese and type 2 diabetes mellitus human subjects (P < .02). RNAi-mediated suppression of Ahi-1 resulted in increased glucose transport in rat L6 myotubes in both the basal and insulin-stimulated states (P < .01). Finally, single nucleotide polymorphism association studies identified 2 novel AHI1 genetic variants linked with fasting blood glucose levels in Mexican American subjects (P < .037). These findings indicate a novel role for AHI1 in skeletal muscle and identify additional genetic links with metabolic syndrome phenotypes suggesting an involvement of AHI1 in the maintenance of glucose homeostasis and type 2 diabetes mellitus progression.
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Proteínas Adaptadoras Transductoras de Señales/metabolismo , Síndrome Metabólico/metabolismo , Músculo Esquelético/metabolismo , Proteínas Adaptadoras Transductoras de Señales/genética , Proteínas Adaptadoras del Transporte Vesicular , Animales , Glucemia/metabolismo , Western Blotting , Peso Corporal/fisiología , Células Cultivadas , Estudios de Cohortes , Desoxiglucosa/metabolismo , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Genotipo , Glucosa/metabolismo , Humanos , Insulina/sangre , Resistencia a la Insulina/genética , Síndrome Metabólico/genética , Americanos Mexicanos , Fibras Musculares Esqueléticas/metabolismo , Mioblastos/efectos de los fármacos , Mioblastos/metabolismo , Obesidad/metabolismo , ARN Mensajero/biosíntesis , ARN Mensajero/genética , Ratas , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , TransfecciónRESUMEN
Type 2 diabetes mellitus (T2DM) and aging are characterized by insulin resistance and impaired mitochondrial energetics. In lower organisms, remodeling by the protease pcp1 (PARL ortholog) maintains the function and lifecycle of mitochondria. We examined whether variation in PARL protein content is associated with mitochondrial abnormalities and insulin resistance. PARL mRNA and mitochondrial mass were both reduced in elderly subjects and in subjects with T2DM. Muscle knockdown of PARL in mice resulted in malformed mitochondrial cristae, lower mitochondrial content, decreased PGC1alpha protein levels, and impaired insulin signaling. Suppression of PARL protein in healthy myotubes lowered mitochondrial mass and insulin-stimulated glycogen synthesis and increased reactive oxygen species production. We propose that lower PARL expression may contribute to the mitochondrial abnormalities seen in aging and T2DM.
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Insulina/metabolismo , Metaloproteasas/metabolismo , Mitocondrias/enzimología , Proteínas Mitocondriales/metabolismo , Músculo Esquelético/enzimología , Transducción de Señal , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Envejecimiento/metabolismo , Animales , Células Cultivadas , Diabetes Mellitus Tipo 2/metabolismo , Glucógeno/metabolismo , Humanos , Metaloproteasas/deficiencia , Metaloproteasas/genética , Ratones , Ratones Noqueados , Persona de Mediana Edad , Mitocondrias/metabolismo , Proteínas Mitocondriales/deficiencia , Proteínas Mitocondriales/genética , Músculo Esquelético/citología , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma , Especies Reactivas de Oxígeno/metabolismo , Transactivadores/metabolismo , Factores de TranscripciónRESUMEN
CONTEXT: Chemerin is a novel adipokine previously associated with metabolic syndrome phenotypes in a small sample of subjects from Mauritius. OBJECTIVE: The aim of the study was to determine whether plasma chemerin levels were associated with metabolic syndrome phenotypes in a larger sample from a second, unrelated human population. DESIGN, SETTING, PATIENTS, AND INTERVENTION: Plasma samples were obtained from the San Antonio Family Heart Study (SAFHS), a large family-based genetic epidemiological study including 1431 Mexican-American individuals. Individuals were randomly sampled without regard to phenotype or disease status. This sample is well-characterized for a variety of phenotypes related to the metabolic syndrome. MAIN OUTCOMES: Plasma chemerin levels were measured by sandwich ELISA. Linear regression and correlation analyses were used to determine associations between plasma chemerin levels and metabolic syndrome phenotypes. RESULTS: Circulating chemerin levels were significantly higher in nondiabetic subjects with body mass index (BMI) greater than 30 kg/m(2) compared with those with a BMI below 25 kg/m(2) (P < 0.0001). Plasma chemerin levels were significantly associated with metabolic syndrome-related parameters, including BMI (P < 0.0001), fasting serum insulin (P < 0.0001), triglycerides (P < 0.0001), and high-density lipoprotein cholesterol (P = 0.00014), independent of age and sex in nondiabetic subjects. CONCLUSION: Circulating chemerin levels were associated with metabolic syndrome phenotypes in a second, unrelated human population. This replicated result using a large human sample suggests that chemerin may be involved in the development of the metabolic syndrome.
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Quimiocinas/sangre , Síndrome Metabólico/sangre , Síndrome Metabólico/etnología , Americanos Mexicanos , Adulto , Anciano , Quimiocinas/fisiología , Diabetes Mellitus Tipo 2/sangre , Femenino , Humanos , Péptidos y Proteínas de Señalización Intercelular , Masculino , Persona de Mediana Edad , Obesidad/sangre , Sobrepeso/sangre , FenotipoRESUMEN
Selenoprotein S (SEPS1) is a novel endoplasmic reticulum (ER) resident protein and it is known to play an important role in production of inflammatory cytokines. Here, we show evidence that SEPS1 is stimulated by pharmacological ER stress agents in RAW264.7 macrophages as well as other cell types. Overexpression studies reveal a protective action of SEPS1 in macrophages against ER stress-induced cytotoxicity and apoptosis, resulting in promoting cell survival during ER stress. The protective action of SEPS1 is largely dependent on ER stress-mediated cell death signal with less effect on non-ER stress component cell death signals. Conversely, suppression of SEPS1 in macrophages results in sensitization of cells to ER stress-induced cell death. These findings suggest that SEPS1 could be a new ER stress-dependent survival factor that protects macrophage against ER stress-induced cellular dysfunction.