RESUMEN

PURPOSE: Retrotransposons play important roles during early development when they are transiently de-repressed during epigenetic reprogramming. Long interspersed element-1 (L1), the only autonomous retrotransposon in humans, comprises 17% of the human genome. We applied the Single Cell Transposon Insertion Profiling by Sequencing (scTIPseq) to characterize and map L1 insertions in human embryos. METHODS: Sixteen cryopreserved, genetically tested, human blastocysts, were accessed from consenting couples undergoing IVF at NYU Langone Fertility Center. Additionally, four trios (father, mother, and embryos) were also evaluated. scTIPseq was applied to map L1 insertions in all samples, using L1 locations reported in the 1000 Genomes as controls. RESULTS: Twenty-nine unknown and unique insertions were observed in the sixteen embryos. Most were intergenic; no insertions were located in exons or immediately upstream of genes. The location or number of unknown insertions did not differ between euploid and aneuploid embryos, suggesting they are not merely markers of aneuploidy. Rather, scTIPseq provides novel information about sub-chromosomal structural variation in human embryos. Trio analyses showed a parental origin of all L1 insertions in embryos. CONCLUSION: Several studies have measured L1 expression at different stages of development in mice, but this study for the first time reports unknown insertions in human embryos that were inherited from one parent, confirming no de novo L1 insertions occurred in parental germline or during embryogenesis. Since one-third of euploid embryo transfers fail, future studies would be useful for understanding whether these sub-chromosomal genetic variants or de novo L1 insertions affect embryo developmental potential.

Asunto(s)

Blastocisto , Elementos de Nucleótido Esparcido Largo , Humanos , Elementos de Nucleótido Esparcido Largo/genética , Blastocisto/metabolismo , Femenino , Embrión de Mamíferos/metabolismo , Desarrollo Embrionario/genética , Mutagénesis Insercional/genética , Aneuploidia , Genoma Humano/genética , Fertilización In Vitro , Masculino , Variación Genética/genética , Ratones , Mapeo Cromosómico/métodos

RESUMEN

BACKGROUND: Long interspersed element 1 (LINE-1 or L1) retrotransposons are mobile elements that constitute 17-20% of the human genome. Strong correlations between abnormal L1 expression and several human diseases have been reported. This has motivated increasing interest in accurate quantification of the number of L1 copies present in any given biologic specimen. A main obstacle toward this aim is that L1s are relatively long DNA segments with regions of high variability, or largely present in the human genome as truncated fragments. These particularities render traditional alignment strategies, such as seed-and-extend inefficient, as the number of segments that are similar to L1s explodes exponentially. This study uses the pattern matching methodology for more accurate identification of L1s. We validate experimentally the superiority of pattern matching for L1 detection over alternative methods and discuss some of its potential applications. RESULTS: Pattern matching detected full-length L1 copies with high precision, reasonable computational time, and no prior input information. It also detected truncated and significantly altered copies of L1 with relatively high precision. The method was effectively used to annotate L1s in a target genome and to calculate copy number variation with respect to a reference genome. Crucial to the success of implementation was the selection of a small set of k-mer probes from a set of sequences presenting a stable pattern of distribution in the genome. As in seed-and-extend methods, the pattern matching algorithm sowed these k-mer probes, but instead of using heuristic extensions around the seeds, the analysis was based on distribution patterns within the genome. The desired level of precision could be adjusted, with some loss of recall. CONCLUSION: Pattern matching is more efficient than seed-and-extend methods for the detection of L1 segments whose characterization depends on a finite set of sequences with common areas of low variability. We propose that pattern matching may help establish correlations between L1 copy number and disease states associated with L1 mobilization and evolution.

Asunto(s)

Variaciones en el Número de Copia de ADN , Genoma Humano , Humanos , Elementos de Nucleótido Esparcido Largo/genética , Retroelementos

RESUMEN

This study aimed to understand the impact of LINE-1 and SINE-B1 retroelements on the architecture and karyotypic diversification of five rodent species of the genus Proechimys from different regions of the Amazon. Karyotype comparisons were performed using fluorescent interspecific in situ hybridization. The L1 and B1 retroelements showed a non-random arrangement and a conserved pattern when the genomes of the five species of Proechimys were compared, including the two cytotypes of Proechimys guyannensis The signal homeology among the chromosomes and the degree of similarity among the formed clusters indicate rearrangements such as fusion/fission, and demonstrates that these retroelements can behave as derived characters shared in Proechimys The differentiated distribution and organization of these retroelements in the karyotypes and in the chromosomal fiber, respectively, may represent a strong indication of their role as generating sources of karyotypic diversity in the genus Proechimys and provide insights into the evolutionary relationships between taxa.

Asunto(s)

Retroelementos , Roedores , Animales , Cromosomas , Elementos de Nucleótido Esparcido Largo/genética , Retroelementos/genética , Roedores/genética

RESUMEN

Down syndrome (DS) is the most common chromosomal disorder, resulting from the failure of normal chromosome 21 segregation. Studies have suggested that impairments within the one-carbon metabolic pathway can be of relevance for the global genome instability observed in mothers of individuals with DS. Based on the association between global DNA hypomethylation, genome instability, and impairments within the one-carbon metabolic pathway, the present study aimed to identify possible predictors, within the one-carbon metabolism, of global DNA methylation, measured by methylation patterns of LINE-1 and Alu repetitive sequences, in mothers of individuals with DS and mothers of individuals without the syndrome. In addition, we investigated one-carbon genetic polymorphisms and metabolites as maternal predisposing factors for the occurrence of trisomy 21 in children. Eighty-three samples of mothers of children with DS with karyotypically confirmed free trisomy 21 (case group) and 84 of mothers who had at least one child without DS or any other aneuploidy were included in the study. Pyrosequencing assays were performed to access global methylation. The results showed that group affiliation (case or control), betaine-homocysteine methyltransferase (BHMT) G742A and transcobalamin 2 (TCN2) C776G polymorphisms, and folate concentration were identified as predictors of global Alu DNA methylation values. In addition, thymidylate synthase (TYMS) 28-bp repeats 2R/3R or 3R/3R genotypes are independent maternal predisposing factors for having a child with DS. This study adds evidence that supports the association of impairments in the one-carbon metabolism, global DNA methylation, and the possibility of having a child with DS.

Asunto(s)

Carbono/metabolismo , Metilación de ADN/genética , Síndrome de Down/genética , Síndrome de Down/metabolismo , Estudio de Asociación del Genoma Completo , Inestabilidad Genómica/genética , Relaciones Madre-Hijo , Madres , Adolescente , Adulto , Anciano , Elementos Alu/genética , Betaína-Homocisteína S-Metiltransferasa/genética , Betaína-Homocisteína S-Metiltransferasa/metabolismo , Femenino , Ácido Fólico/metabolismo , Predisposición Genética a la Enfermedad/genética , Humanos , Elementos de Nucleótido Esparcido Largo/genética , Masculino , Persona de Mediana Edad , Polimorfismo Genético , Transducción de Señal/genética , Transducción de Señal/fisiología , Timidilato Sintasa/genética , Transcobalaminas/genética , Transcobalaminas/metabolismo , Adulto Joven

RESUMEN

Alterations of global DNA methylation have been evaluated in several studies worldwide; however, Long Interspersed Nuclear Elements-1 (LINE-1) methylation in genetically conserved populations such as indigenous communities have not, to our knowledge, been reported. The aim of this study was to evaluate the relationship between LINE-1 methylation patterns and factors such as pesticide exposure and socio-cultural characteristics in the Indigenous Huichol Population of Nayarit, Mexico. A cross-sectional study was conducted in 140 Huichol indigenous individuals. A structured questionnaire was used to determine general and anthropometric characteristics, diet, harmful habits, and pesticide exposure. DNA methylation was determined by pyrosequencing of bisulfite-treated DNA. A lower level of LINE-1 methylation was found in the indigenous population when compared to a Mestizo population previously studied by our group. This difference might be due to the influence of the genetic admixture and differing dietary and lifestyle habits. The males in the indigenous population exhibited increased LINE-1 methylation in comparison to the females. Sex and alcohol consumption showed positive associations with LINE-1 methylation, while weight, current work in the field, current pesticide usage, and folate intake exhibited negative associations with LINE-1 methylation. The results suggest that ethnicity, as well as other internal and environmental factors, might influence LINE-1 methylation.

Asunto(s)

Metilación de ADN , Grupos de Población , Estudios Transversales , Femenino , Humanos , Elementos de Nucleótido Esparcido Largo/genética , Masculino , México

RESUMEN

PURPOSE: Construction workers are exposed to a mixture of substances in the workplace considered carcinogenic. This study aimed to characterise gene-specific changes in DNA methylation over the workweek in this population as this type of environmental exposure has not been studied extensively. MATERIALS AND METHODS: We evaluated their DNA methylation in 4 gene-promoter regions (CDKN2A, RASSF1A, MLH1 and APC) and 2 repeat elements (ALU and LINE-1) in blood samples obtained on the first and fifth day of the same workweek of a group of 39 male construction workers. DNA methylation was measured by bisulphite-PCR-Pyrosequencing. We also measured the levels of trace elements in the whole blood by ICP-MS. RESULTS: Only the CDKN2A gene had significant differences in the average methylation level between the first and fifth day of the workweek. We also observed that the levels of Cu, Pb, Se, Mn, and Ti decreased during the fifth day of exposure, and only lead, titanium and copper showed a low significant correlation with the methylation level mean for three specific CpG sites of the CDKN2A. CONCLUSIONS: In summary, the data suggest that altered levels of CDKN2A methylation in construction workers may be a potential biomarker of recent exposure in this environment.

Asunto(s)

Inhibidor p16 de la Quinasa Dependiente de Ciclina/genética , Metilación de ADN/genética , Epigénesis Genética , Exposición Profesional/efectos adversos , Adulto , Elementos Alu/genética , Biomarcadores/sangre , Industria de la Construcción , Humanos , Elementos de Nucleótido Esparcido Largo/genética , Masculino , Homólogo 1 de la Proteína MutL/genética , Regiones Promotoras Genéticas/genética , Proteínas Supresoras de Tumor/genética

RESUMEN

CONTEXT: Androgen insensitivity syndrome (AIS) is the most common cause of disorders of sex development in 46,XY individuals. It is an X-linked condition usually caused by pathogenic allelic variants in the androgen receptor (AR) gene. The phenotype depends on the AR variant, ranging from severe undervirilization (complete AIS) to several degrees of external genitalia undervirilization. Although 90% of those with complete AIS will have AR mutations, this will only be true for 40% of those with partial AIS (PAIS). OBJECTIVE: To identify the genetic etiology of AIS in a large multigenerational family with the PAIS phenotype. PARTICIPANTS: Nine affected individuals with clinical and laboratory findings consistent with PAIS and a normal exonic AR sequencing. SETTINGS: Endocrine clinic and genetic institute from two academic referral centers. DESIGN: Analysis of whole exons of the AR gene, including splicing regions, was performed, followed by sequencing of the 5'untranslated region (UTR) of the AR gene. Detailed phenotyping was performed at the initial diagnosis and long-term follow-up, and circulating levels of steroid gonadal hormones were measured in all affected individuals. AR expression was measured using RT-PCR and cultured fibroblasts. RESULTS: All 46,XY family members with PAIS had inherited, in hemizygosity, a complex defect (∼1100 bp) in the 5'UTR region of the AR surrounded by a duplicated 18-bp sequence (target site duplication). This sequence is 99.7% similar to an active, long, interspersed element present on the X chromosome (AC002980; Xq22.2), which was inserted in the 5'UTR of the AR gene, severely reducing AR expression and leading to PAIS. CONCLUSION: The molecular diagnosis of PAIS remains challenging. The genomic effect of retrotransposon mobilization should be considered a possible molecular cause of AIS and other AR diseases.

Asunto(s)

Síndrome de Resistencia Androgénica/etiología , Cromosomas Humanos X/genética , Elementos de Nucleótido Esparcido Largo/genética , Mutación , Receptores Androgénicos/genética , Adolescente , Adulto , Síndrome de Resistencia Androgénica/patología , Niño , Preescolar , Femenino , Estudios de Seguimiento , Humanos , Lactante , Masculino , Linaje , Fenotipo , Pronóstico

RESUMEN

Cardiovascular risk associated with fetal growth restriction (FGR) could result from an early impaired vascular function. However, whether this effect results in premature vascular aging has not been addressed. We studied the ex vivo reactivity of carotid and femoral arteries in fetal (near term), adults (eight months-old) and aged (16 months-old) guinea pigs in normal (control) and FGR offspring. Additionally, an epigenetic marker of vascular aging (i.e., LINE-1 DNA methylation) was evaluated in human umbilical artery endothelial cells (HUAEC) from control and FGR subjects. Control guinea pig arteries showed an increased contractile response (KCl-induced) and a progressive impairment of NO-mediated relaxing responses as animals get older. FGR was associated with an initial preserved carotid artery reactivity as well as a later significant impairment in NO-mediated responses. Femoral arteries from FGR fetuses showed an increased contractility but a decreased relaxing response compared with control fetuses, and both responses were impaired in FGR-adults. Finally, FGR-HUAEC showed decreased LINE-1 DNA methylation compared with control-HUAEC. These data suggest that the aging of vascular function occurs by changes in NO-mediated responses, with limited alterations in contractile capacity. Further, these effects are accelerated and imposed at early stages of development in subjects exposed to a suboptimal intrauterine environment.

Asunto(s)

Envejecimiento/patología , Endotelio Vascular/crecimiento & desarrollo , Retardo del Crecimiento Fetal/patología , Animales , Arterias Carótidas/crecimiento & desarrollo , Arterias Carótidas/patología , Arterias Carótidas/fisiopatología , Células Cultivadas , Metilación de ADN , Endotelio Vascular/metabolismo , Endotelio Vascular/patología , Femenino , Arteria Femoral/crecimiento & desarrollo , Arteria Femoral/patología , Arteria Femoral/fisiopatología , Retardo del Crecimiento Fetal/genética , Cobayas , Humanos , Elementos de Nucleótido Esparcido Largo/genética , Óxido Nítrico/metabolismo , Vasoconstricción , Vasodilatación

RESUMEN

STUDY OBJECTIVES: Sleep deprivation and low sleep quality are widespread among adolescents, and associate with obesity risk. Plausible mediators include diet and physical activity. Another potential interrelated pathway, as yet unexplored in adolescents, could involve epigenetic modification of metabolism genes. METHODS: In a cohort of 351 Mexico City adolescents (47% male; mean [SD] age = 14 [2] years), 7-day actigraphy was used to assess average sleep duration, sleep fragmentation, and movement index. DNA isolated from blood leukocytes was bisulfite-converted, amplified, and pyrosequenced at four candidate regions. Linear mixed models evaluated sex-stratified associations between sleep characteristics (split into quartiles [Q]) and DNA methylation of each region, adjusted for potential confounders. RESULTS: Mean sleep duration was 8.5 [0.8] hours for boys and 8.7 [1] hours for girls. There were sex-specific associations between sleep duration and LINE-1 (long interspersed nuclear element) methylation. Boys with longer sleep duration (Q4) had lower LINE-1 methylation than boys in the 3rd quartile reference category, while girls with both longer and shorter sleep duration had higher LINE-1 methylation compared to Q3. Longer sleep duration was associated with higher H19 methylation among girls (comparing highest to third quartile, -0.9% [-2.2, 0.5]; p, trend = 0.047). Sleep fragmentation was inversely associated with peroxisome proliferator-activated receptor alpha (PPARA) methylation among girls (comparing highest to lowest fragmentation quartile, 0.9% [0.1 to 1.8]). Girls also showed an inverse association between sleep fragmentation and hydroxysteroid (11-beta) dehydrogenase 2 (HSD11B2; Q4 to Q1, 0.6% [-1.2%, 0%]). CONCLUSIONS: Sleep duration and fragmentation in adolescents show sex-specific associations with leukocyte DNA methylation patterns of metabolism genes.

Asunto(s)

Metilación de ADN/genética , ADN/metabolismo , Epigénesis Genética/genética , Privación de Sueño/genética , Sueño/fisiología , Actigrafía , Adolescente , Dieta , Ejercicio Físico , Femenino , Humanos , Leucocitos/metabolismo , Elementos de Nucleótido Esparcido Largo/genética , Masculino , México , Obesidad/metabolismo , Privación de Sueño/metabolismo , Factores de Tiempo

RESUMEN

Activity of the human long interspersed nuclear elements-1 (LINE-1) retrotransposon occurs mainly in early embryonic development and during hippocampal neurogenesis. SOX-11, a transcription factor relevant to neuronal development, has unknown functions in the control of LINE-1 retrotransposon activity during neuronal differentiation. To study the dependence of LINE-1 activity on SOX-11 during neuronal differentiation, we induced differentiation of human SH-SY5Y neuroblastoma cells and adult adipose mesenchymal stem cells (hASCs) to a neuronal fate and found increased LINE-1 activity. We also show that SOX-11 protein binding to the LINE-1 promoter is higher in differentiating neuroblastoma cells, while knock-down of SOX-11 inhibits the induction of LINE-1 transcription in differentiating conditions. These results suggest that activation of LINE-1 retrotransposition during neuronal differentiation is mediated by SOX-11.

Asunto(s)

Diferenciación Celular/genética , Elementos de Nucleótido Esparcido Largo/genética , Neuronas/metabolismo , Factores de Transcripción SOXC/genética , Tejido Adiposo/citología , Línea Celular Tumoral , Células Cultivadas , Regulación de la Expresión Génica , Células HEK293 , Células HeLa , Humanos , Células Madre Mesenquimatosas/citología , Células Madre Mesenquimatosas/metabolismo , Neurogénesis/genética , Neuronas/citología , Interferencia de ARN , Factores de Transcripción SOXC/metabolismo

RESUMEN

Exposure to ionizing radiation greatly increases the risk of developing papillary thyroid carcinoma (PTC), especially during childhood, mainly due to gradual inactivation of DNA repair genes and DNA damages. Recent molecular characterization of PTC revealed DNA methylation deregulation of several promoters of DNA repair genes. Thus, epigenetic silencing might be a plausible mechanism for the activity loss of tumor suppressor genes in radiation-induced thyroid tumors. Herein, we investigated the impact of ionizing radiation on global methylation and CpG islands within promoter regions of homologous recombination (HR) and non-homologous end joining (NHEJ) genes, as well as its effects on gene expression, using two well-established normal differentiated thyroid cell lines (FRTL5 and PCCL3). Our data reveal that X-ray exposure promoted G2/M arrest in normal thyroid cell lines. The FRTL5 cells displayed a slower kinetics of double-strand breaks (DSB) repair and a lower long interspersed nuclear element-1 (LINE-1) methylation than the PCCL3 cells. Nevertheless, acute X-ray exposure does not alter the expression of genes involved in HR and NHEJ pathways, apart from the downregulation of Brca1 in thyroid cells. On the other hand, HR and NHEJ gene expressions were upregulated in radiation-induced senescent thyroid cells. Taken together, these data suggest that FRTL5 cells intrinsically have less efficient DNA DSB repair machinery than PCCL3 cells, as well as genomic instability, which could predispose the FRTL5 cells to unrepaired DSB lesions and, therefore, gene mutations.

Asunto(s)

Proteína BRCA1/genética , Metilación de ADN/efectos de la radiación , Reparación del ADN/efectos de la radiación , Regulación de la Expresión Génica/efectos de la radiación , Elementos de Nucleótido Esparcido Largo/genética , Glándula Tiroides/citología , Animales , Línea Celular , Senescencia Celular/efectos de la radiación , Roturas del ADN de Doble Cadena/efectos de la radiación , Reparación del ADN por Unión de Extremidades/efectos de la radiación , Recombinación Homóloga/efectos de la radiación , Cinética , Fenotipo , Regiones Promotoras Genéticas/genética , ARN Mensajero/genética , ARN Mensajero/metabolismo , Ratas , Glándula Tiroides/metabolismo , Glándula Tiroides/efectos de la radiación , Regulación hacia Arriba/efectos de la radiación

RESUMEN

Arsenic is a carcinogen and epimutagen that threatens the health of exposed populations worldwide. In this study, we examined the methylation status of Alu and long interspersed nucleotide elements (LINE-1) and their association with levels of urinary arsenic in 84 Mexican children between 6 and 12 years old from two historic mining areas in the State of San Luis Potosí, Mexico. Urinary arsenic levels were determined by atomic absorption spectrophotometry and DNA methylation analysis was performed in peripheral blood leukocytes by bisulfite-pyrosequencing. The geometric mean of urinary arsenic was 26.44 µg/g Cr (range 1.93-139.35). No significant differences in urinary arsenic or methylation patterns due to gender were observed. A positive correlation was found between urinary arsenic and the mean percentage of methylated cytosines in Alu sequences (Spearman correlation coefficient r = 0.532, P < 0.001), and a trend of LINE-1 hypomethylation was also observed (Spearman correlation coefficient r = -0.232, P = 0.038) after adjustment for sex and age. A linear regression model showed an association with log-normalized urinary arsenic for Alu (ß = 1.05, 95% CI: 0.67; 1.43, P < 0.001) and LINE-1 (ß = -0.703, 95% CI: -1.36; -0.38, P = 0.038). Despite the low-level arsenic exposure, a subtle epigenetic imbalance measured as DNA methylation was detected in the leukocytes of Mexican children living in two historic mining areas. Environ. Mol. Mutagen. 57:717-723, 2016. © 2016 Wiley Periodicals, Inc.

Asunto(s)

Arsénico/toxicidad , Metilación de ADN/efectos de los fármacos , Exposición a Riesgos Ambientales/análisis , Contaminantes Ambientales/toxicidad , Minería , Elementos Alu/genética , Arsénico/orina , Niño , Ciudades , Estudios Transversales , Contaminantes Ambientales/orina , Femenino , Humanos , Leucocitos/efectos de los fármacos , Leucocitos/metabolismo , Elementos de Nucleótido Esparcido Largo/genética , México , Embarazo , Análisis de Regresión , Población Urbana

RESUMEN

Epigenetic dysregulation is an important emerging hallmark of cutaneous melanoma development. The global loss of DNA methylation in gene-poor regions and transposable DNA elements of cancer cells contributes to increased genomic instability. Long interspersed element-1 (LINE-1) sequences are the most abundant repetitive sequence of the genome and can be evaluated as a surrogate marker of the global level of DNA methylation. In this work, LINE-1 methylation levels were evaluated in cutaneous melanomas and normal melanocyte primary cell cultures to investigate their possible association with both distinct clinicopathological characteristics and tumor mutational profile. A set of driver mutations frequently identified in cutaneous melanoma was assessed by sequencing (actionable mutations in BRAF, NRAS, and KIT genes, and mutations affecting the TER T promoter) or multiplex ligation-dependent probe amplification (MLPA) (CDKN2A deletions). Pyrosequencing was performed to investigate the methylation level of LINE-1 and CDKN2A promoter sequences. The qualitative analysis showed a trend toward an association between LINE-1 hypomethylation and CDKN2A inactivation (p=0.05). In a quantitative approach, primary tumors, mainly the thicker ones (>4 mm), exhibited a trend toward LINE-1 hypomethylation when compared with control melanocytes. To date, this is the first study reporting in cutaneous melanomas a possible link between the dysregulation of LINE-1 methylation and the presence of driver mutations.

Asunto(s)

Metilación de ADN/genética , Elementos de Nucleótido Esparcido Largo/genética , Melanoma/genética , Mutación/genética , Análisis Mutacional de ADN , Humanos , Neoplasias Cutáneas , Melanoma Cutáneo Maligno

RESUMEN

BACKGROUND: Weight loss can be influenced by genetic factors and epigenetic mechanisms that participate in the regulation of body weight. This study aimed to investigate whether the weight loss induced by two different obesity treatments (energy restriction or bariatric surgery) may affect global DNA methylation (LINE-1) and hydroxymethylation profile, as well as the methylation patterns in inflammatory genes. METHODS: This study encompassed women from three differents groups: 1. control group (n = 9), normal weight individuals; 2. energy restriction group (n = 22), obese patients following an energy-restricted Mediterranean-based dietary treatment (RESMENA); and 3. bariatric surgery group (n = 14), obese patients underwent a hypocaloric diet followed by bariatric surgery. Anthropometric measurements and 12-h fasting blood samples were collected before the interventions and after 6 months. Lipid and glucose biomarkers, global hydroxymethylation (by ELISA), LINE-1, SERPINE-1, and IL-6 (by MS-HRM) methylation levels were assessed in all participants. RESULTS: Baseline LINE-1 methylation was associated with serum glucose levels whereas baseline hydroxymethylation was associated with BMI, waist circumference, total cholesterol, and triglycerides. LINE-1 and SERPINE-1 methylation levels did not change after weight loss, whereas IL-6 methylation increased after energy restriction and decreased in the bariatric surgery group. An association between SERPINE-1 methylation and weight loss responses was found. CONCLUSIONS: Global DNA methylation and hydroxymethylation might be biomarkers for obesity and associated comorbidities. Depending on the obesity treatment (diet or surgery), the DNA methylation patterns behave differently. Baseline SERPINE-1 methylation may be a predictor of weight loss values after bariatric surgery.

Asunto(s)

Metilación de ADN/genética , Marcadores Genéticos/genética , Obesidad/genética , Obesidad/terapia , Adulto , Restricción Calórica , Epigénesis Genética , Femenino , Derivación Gástrica , Humanos , Hidroxilación , Interleucina-6/genética , Elementos de Nucleótido Esparcido Largo/genética , Metilación , Persona de Mediana Edad , Obesidad/dietoterapia , Obesidad/cirugía , Inhibidor 1 de Activador Plasminogénico/genética , Pérdida de Peso/genética , Adulto Joven

RESUMEN

BACKGROUND: Global methylation level in blood leukocyte DNA has been associated with the risk of coronary heart disease (CHD), with inconsistent results in various populations. Similar data are lacking in Chinese population where different genetic, lifestyle and environmental factors may affect DNA methylation and its risk relationship with CHD. OBJECTIVES: To examine whether global methylation is associated with the risk of CHD in Chinese population. METHODS: A total of 334 cases with CHD and 788 healthy controls were included. Global methylation in blood leukocyte DNA was estimated by analyzing LINE-1 repeats using bisulfite pyrosequencing. RESULTS: In an initial analysis restricted to control subjects, LINE-1 level reduced significantly with aging, elevated total cholesterol, and diagnosis of diabetes. In the case-control analysis, reduced LINE-1 methylation was associated with increased risk of CHD; analysis by quartile revealed odds ratios (95%CI) of 0.9 (0.6-1.4), 1.9 (1.3-2.9) and 2.3 (1.6-3.5) for the third, second and first (lowest) quartile (Ptrend < 0.001), respectively, compared to the fourth (highest) quartile. Lower (

Asunto(s)

Pueblo Asiatico/genética , Enfermedad Coronaria/genética , Metilación de ADN/genética , Elementos de Nucleótido Esparcido Largo/genética , Factores de Edad , Anciano , Índice de Masa Corporal , Estudios de Casos y Controles , Distribución de Chi-Cuadrado , China , Enfermedad Coronaria/etnología , Complicaciones de la Diabetes , Humanos , Hipertensión/complicaciones , Leucocitos , Persona de Mediana Edad , Reacción en Cadena de la Polimerasa , Valores de Referencia , Medición de Riesgo , Factores de Riesgo , Factores Sexuales

RESUMEN

Fundamentos: O nível de metilação global do ADN de leucócitos no sangue tem sido associado ao risco de doença arterial coronariana (DAC), com resultados inconsistentes em diferentes populações. Faltam dados semelhantes da população chinesa, onde diferentes fatores genéticos, de estilo de vida e ambientais podem afetar a metilação do ADN e sua relação com o risco de DCC. Objetivos: Analisar se a metilação global está associada ao risco de doença coronariana na população chinesa. Métodos: Foram incluídos um total de 334 casos de DCC e 788 controles saudáveis. A metilação global do ADN de leucócitos de sangue foi estimada por meio da análise das repetições do LINE-1 usando pirosequenciamento de bissulfito. Resultados: Em uma análise inicial restrita aos controles o nível do LINE-1 diminui significativamente com a idade avançada, colesterol total elevado, e diagnóstico de diabetes. Na análise de caso-controle, a redução da metilação do LINE-1 foi associada ao aumento do risco de DCC, tendo a análise por quartil revelado uma odds ratio (IC 95%) de 0,9 (0,6-1,4), 1,9 (1,3-2,9) e 2,3 (1,6 3.5) para o terceiro, segundo e primeiro (o mais baixo) quartil (P da tendência < 0,001), respectivamente, em comparação com o quarto (o mais alto) quartil. A metilação inferior (< mediana) do LINE-1 esteve associada a 2,2 vezes (IC 95% = 1,7-3,0) o aumento de risco de doença coronariana. As estimativas de risco de DCC menores relacionadas com o LINE-1 tenderam a ser mais fortes entre os indivíduos com maior tercil de homocisteína (P interação = 0,042) e naqueles com diagnóstico de hipertensão arterial (P interação = 0,012). Conclusão: A hipometilação do LINE-1 está ...

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Background: Global methylation level in blood leukocyte DNA has been associated with the risk of coronary heart disease (CHD), with inconsistent results in various populations. Similar data are lacking in Chinese population where different genetic, lifestyle and environmental factors may affect DNA methylation and its risk relationship with CHD. Objectives: To examine whether global methylation is associated with the risk of CHD in Chinese population. Methods: A total of 334 cases with CHD and 788 healthy controls were included. Global methylation in blood leukocyte DNA was estimated by analyzing LINE-1 repeats using bisulfite pyrosequencing. Results: In an initial analysis restricted to control subjects, LINE-1 level reduced significantly with aging, elevated total cholesterol, and diagnosis of diabetes. In the case-control analysis, reduced LINE-1 methylation was associated with increased risk of CHD; analysis by quartile revealed odds ratios (95%CI) of 0.9 (0.6-1.4), 1.9 (1.3-2.9) and 2.3 (1.6-3.5) for the third, second and first (lowest) quartile (Ptrend < 0.001), respectively, compared to the fourth (highest) quartile. Lower (<median) LINE-1 methylation was associated with a 2.2-fold (95%CI = 1.7-3.0) increased risk of CHD. The lower LINE-1-related CHD risk estimates tended to be stronger among subjects with the highest tertile of homocysteine (Pinteraction = 0.042) and those with diagnosis of hypertension (Pinteraction = 0.012). Conclusion: LINE-1 hypomethylation is associated with the risk of CHD in Chinese population. Potential CHD risk factors such as older age, elevated total cholesterol, and diagnosis of diabetes may have impact on global DNA methylation, whereby exerting their effect on CHD risk. .

Asunto(s)

Anciano , Humanos , Persona de Mediana Edad , Pueblo Asiatico/genética , Enfermedad Coronaria/genética , Metilación de ADN/genética , Elementos de Nucleótido Esparcido Largo/genética , Factores de Edad , Índice de Masa Corporal , Estudios de Casos y Controles , Distribución de Chi-Cuadrado , China , Enfermedad Coronaria/etnología , Complicaciones de la Diabetes , Hipertensión/complicaciones , Leucocitos , Reacción en Cadena de la Polimerasa , Valores de Referencia , Medición de Riesgo , Factores de Riesgo , Factores Sexuales

RESUMEN

The human proto-oncogene long interspersed nucleotide acid element-1 (LINE-1) open reading frame-1 protein (ORF-1p) is involved in the progress of several cancers. The transcription factor ETS-1 can mediate the transcription of some downstream genes that play specific roles in the regulation of cancerous cell invasion and metastasis. In this study, the effects of LINE-1 ORF-1p on ETS-1 activity and on the proliferation and invasion of human colorectal cancer LoVo cells were investigated. Results showed that the overexpression of LINE-1 ORF-1p enhanced the transcription of ETS-1 downstream genes and increased their protein levels, and downregulation of the LINE-1 ORF-1p level by small interfering RNA (siRNA) reduced the transcriptional activation of ETS-1. In addition, overexpression of LINE-1 ORF-1p promoted LoVo cell proliferation and anchor-independent growth, and a knockdown of the LINE-1 protein level by siRNA reduced the proliferation and anchor-independent growth ability of LoVo cells. In vivo data revealed that LINE-1 ORF-1p overexpression increased LoVo tumor growth in nude mice, whereas the siRNA knockdown of endogenous LINE-1 ORF-1p expression decreased LoVo cell growth in nude mice. Therefore, LINE- 1 ORF-1p could promote LoVo cell proliferation and invasion both in vitro and in vivo, indicating that it might be a useful molecular target for the treatment of human colorectal cancer.

Asunto(s)

Proliferación Celular/genética , Neoplasias Colorrectales/genética , Elementos de Nucleótido Esparcido Largo/genética , Sistemas de Lectura Abierta/genética , Proteína Proto-Oncogénica c-ets-1/genética , Animales , Western Blotting , Línea Celular Tumoral , Neoplasias Colorrectales/metabolismo , Neoplasias Colorrectales/patología , Células HT29 , Células Hep G2 , Humanos , Proteínas Inhibidoras de la Apoptosis/metabolismo , Células MCF-7 , Masculino , Metaloproteinasa 1 de la Matriz/metabolismo , Metaloproteinasa 9 de la Matriz/metabolismo , Ratones Endogámicos BALB C , Ratones Desnudos , Invasividad Neoplásica , Proto-Oncogenes Mas , Proteína Proto-Oncogénica c-ets-1/metabolismo , Interferencia de ARN , Survivin , Activación Transcripcional/genética , Trasplante Heterólogo , Ensayos Antitumor por Modelo de Xenoinjerto/métodos

RESUMEN

OBJECTIVE: DNA methylation has been shown to be critical in the regulation of inflammatory genes. Infections are able to trigger susceptibility to disease and it can be considered as potential epimutagenic factors in reshaping the epigenome. Therefore, what would be the DNA methylation status in cells present in an infected and inflamed oral environment? The aim was to verify the DNA methylation pattern in oral epithelium cells from aggressive periodontitis (AgP) patients in a specific gene involved in the inflammation control, as suppressor of cytokine signalling (SOCS)1 and in a broader way through long interspersed nuclear element (LINE)-1. DESIGN: Genomic DNA from oral cells of 30 generalized AgP patients and 30 healthy patients were purified and modified by sodium bisulfite. DNA methylation patterns were analyzed using combined bisulfite restriction analysis (COBRA) for SOCS1 and LINE-1. RESULTS: An overall scenario of demethylation was seen for both groups, whereas the healthy group presented a higher percentage of demethylation (p<0.001), also presenting the majority of total demethylated samples (83.3% versus 70.8% in the AgP group). Total LINE-1 methylation or at each specific loci presented significant differences amongst groups. CONCLUSION: Epithelial cells, present in an infected and inflamed oral environment, show different DNA methylation status from those present in a healthy oral environment, regarding the SOCS1 and LINE-1. In addition, the investigation allows detecting alterations in the DNA in a non-limited manner, since the results observed might reflect a generalized condition of the oral epithelial cells, besides reflecting the condition of the gingival epithelium cells.

Asunto(s)

Periodontitis Agresiva/genética , Metilación de ADN , Elementos de Nucleótido Esparcido Largo/genética , Proteínas Supresoras de la Señalización de Citocinas/genética , Adulto , Estudios de Casos y Controles , Femenino , Predisposición Genética a la Enfermedad , Humanos , Masculino

RESUMEN

Alterations in DNA methylation have implicated as an epigenetic event in the pathogenesis of late-onset Alzheimer's disease (LOAD). The objective of this work was to evaluate global DNA methylation levels for long interspersed nuclear element 1 (LINE-1) repetitive sequences in Colombian patients with LOAD and controls. The LINE-1 DNA methylation levels in peripheral blood samples from 28 Colombian patients with LOAD and 30 healthy participants were assessed using a methylation-sensitive high-resolution melting (MS-HRM) quantitative assay. We did not find differences in LINE-1 methylation levels between patients with Alzheimer's disease (AD; median 76.2%, interquartile range [IQR]: 69.8-81.9) and control participants (median 79.8%, IQR: 73.2-83.8; P = .3). Additional stratified analyses did not show differences in LINE-1 methylation levels for male or female patients versus controls nor for apolipoprotein E4 carriers and noncarriers. This is the first report of LINE-1 methylation levels in patients with LOAD using the cost-effective MS-HRM technique, and this is the first global DNA methylation study in Latin American patients with AD.

Asunto(s)

Enfermedad de Alzheimer/genética , Metilación de ADN/genética , Elementos de Nucleótido Esparcido Largo/genética , Anciano , Anciano de 80 o más Años , Estudios de Casos y Controles , Colombia , Femenino , Humanos , Modelos Lineales , Masculino

RESUMEN

BACKGROUND: Cadmium, a common food pollutant, alters DNA methylation in vitro. Epigenetic effects might therefore partly explain cadmium's toxicity, including its carcinogenicity; however, human data on epigenetic effects are lacking. OBJECTIVE: We evaluated the effects of dietary cadmium exposure on DNA methylation, considering other environmental exposures, genetic predisposition, and gene expression. METHODS: Concentrations of cadmium, arsenic, selenium, and zinc in blood and urine of nonsmoking women (n = 202) from the northern Argentinean Andes were measured by inductively coupled mass spectrometry. Methylation in CpG islands of LINE-1 (long interspersed nuclear element-1; a proxy for global DNA methylation) and promoter regions of p16 [cyclin-dependent kinase inhibitor 2A (CDKN2A)] and MLH1 (mutL homolog 1) in peripheral blood were measured by bisulfite polymerase chain reaction pyrosequencing. Genotyping (n = 172) for the DNA (cytosine-5-)-methyltransferase 1 gene (DNMT1 rs10854076 and rs2228611) and DNA (cytosine-5-)-methyltransferase 3 beta gene (DNMT3B rs2424913 and rs2424932) was performed with Sequenom iPLEX GOLD SNP genotyping; and gene expression (n = 90), with DirectHyb HumanHT-12 (version 3.0). RESULTS: Cadmium exposure was low: median concentrations in blood and urine were 0.36 and 0.23 µg/L, respectively. Urinary cadmium (natural log transformed) was inversely associated with LINE-1 methylation (ß = -0.50, p = 0.0070; ß = -0.44, p = 0.026, adjusted for age and coca chewing) but not with p16 or MLH1 methylation. Both DNMT1 rs10854076 and DNMT1 rs2228611 polymorphisms modified associations between urinary cadmium and LINE-1 (p-values for interaction in adjusted models were 0.045 and 0.064, respectively). The rare genotypes demonstrated stronger hypomethylation with increasing urinary cadmium concentrations. Cadmium was inversely associated with DNMT3B (r(S) = -0.28, p = 0.0086) but not with DNMT1 expression (r(S) = -0.075, p = 0.48). CONCLUSION: Environmental cadmium exposure was associated with DNA hypomethylation in peripheral blood, and DNMT1 genotypes modified this association. The role of epigenetic modifications in cadmium-associated diseases needs clarification.

Asunto(s)

Cadmio/toxicidad , Metilación de ADN/efectos de los fármacos , Epigénesis Genética/genética , Contaminación de Alimentos , Proteínas Adaptadoras Transductoras de Señales/genética , Argentina , Arsénico/sangre , Arsénico/orina , Secuencia de Bases , Cadmio/sangre , Cadmio/orina , Inhibidor p16 de la Quinasa Dependiente de Ciclina/genética , ADN (Citosina-5-)-Metiltransferasa 1 , ADN (Citosina-5-)-Metiltransferasas/genética , Femenino , Humanos , Elementos de Nucleótido Esparcido Largo/genética , Espectrometría de Masas , Datos de Secuencia Molecular , Homólogo 1 de la Proteína MutL , Proteínas Nucleares/genética , Selenio/sangre , Selenio/orina , Análisis de Secuencia de ADN , Estadísticas no Paramétricas , Zinc/sangre , Zinc/orina , ADN Metiltransferasa 3B