Actinic keratosis - review for clinical practice.

Actinic keratosis (AK) is a lesion that arises as a result of excessive exposure to solar radiation and appearing predominantly on Fitzpatrick phototype I and II skin. Given that some AKs evolve into squamous cell carcinoma, these lesions are considered premalignant in nature, occurring mostly in elderly men and immunosuppressed individuals chronically exposed to ultraviolet (UV) radiation. There are several mechanisms for the formation of AKs; among them are oxidative stress, immunosuppression, inflammation, altered proliferation and dysregulation of cell growth, impaired apoptosis, mutagenesis, and human papillomavirus (HPV). Through the understanding of these mechanisms, several treatments have emerged. Among the options for AK treatment, the most commonly used include 5-fluorouracil (5-FU), cryotherapy, diclofenac, photodynamic therapy (PDT), imiquimod (IQ), retinoids, and ingenol mebutate (IM). There have been recent advances in the treatment options that have seen the emergent use of newer agents such as resiquimod, betulinic acid, piroxicam, and dobesilate. The combination between therapies has presented relevant results with intention to reduce duration of therapy and side effects. All AK cases must be treated because of their propensity to transform into malignancy and further complicate treatment. In addition to medical or surgical care, education about sun exposure prevention remains the best and most cost-effective method for AK prevention. The objective of this article is to conduct a literature review of the clinical presentation of AK including advances in treatment options available.

Epigenetic and Transcriptional Modifications in Repetitive Elements in Petrol Station Workers Exposed to Benzene and MTBE.

Benzene, a known human carcinogen, and methyl tert-butyl ether (MTBE), not classifiable as to its carcinogenicity, are fuel-related pollutants. This study investigated the effect of these chemicals on epigenetic and transcriptional alterations in DNA repetitive elements. In 89 petrol station workers and 90 non-occupationally exposed subjects the transcriptional activity of retrotransposons (LINE-1, Alu), the methylation on repeated-element DNA, and of H3K9 histone, were investigated in peripheral blood lymphocytes. Median work shift exposure to benzene and MTBE was 59 and 408 µg/m³ in petrol station workers, and 4 and 3.5 µg/m³, in controls. Urinary benzene (BEN-U), S-phenylmercapturic acid, and MTBE were significantly higher in workers than in controls, while trans,trans-muconic acid (tt-MA) was comparable between the two groups. Increased BEN-U was associated with increased Alu-Y and Alu-J expression; moreover, increased tt-MA was associated with increased Alu-Y and Alu-J and LINE-1 (L1)-5'UTR expression. Among repetitive element methylation, only L1-Pa5 was hypomethylated in petrol station workers compared to controls. While L1-Ta and Alu-YD6 methylation was not associated with benzene exposure, a negative association with urinary MTBE was observed. The methylation status of histone H3K9 was not associated with either benzene or MTBE exposure. Overall, these findings only partially support previous observations linking benzene exposure with global DNA hypomethylation.

Placental circadian pathway methylation and in utero exposure to fine particle air pollution.

In mammals, a central clock maintains the daily rhythm in accordance with the external environment. At the molecular level, the circadian rhythm is maintained by epigenetic regulation of the Circadian pathway. Here, we tested the role of particulate matter with an aerodynamic diameter ≤ 2.5 µm (PM2.5) exposure during gestational life on human placental Circadian pathway methylation, as an important molecular target for healthy development. In 407 newborns, we quantified placental methylation of CpG sites within the promoter regions of the following genes: CLOCK, BMAL1, NPAS2, CRY1-2 and PER1-3 using bisulfite-PCR-pyrosequencing. Daily PM2.5 exposure levels were estimated for each mother's residence, using a spatiotemporal interpolation model. We applied mixed-effects models to study the methylation status of the Circadian pathway genes and in utero PM2.5 exposure, while adjusting for a priori chosen covariates. In a multi-gene model, placental Circadian pathway methylation was positively and significantly (p < 0.0001) associated with 3rd trimester PM2.5 exposure. Consequently, the single-gene models showed relative methylation differences [Log(fold change)] in placental NPAS2 (+0.16; p = 0.001), CRY1 (+0.59; p = 0.0023), PER2 (+0.36; p = 0.0005), and PER3 (+0.42; p = 0.0008) for an IQR increase (8.9 µg/m3) in 3rd trimester PM2.5 exposure. PM2.5 air pollution, an environmental risk factor leading to a pro-inflammatory state of the mother and foetus, is associated with the methylation pattern of genes in the Circadian pathway. The observed alterations in the placental CLOCK epigenetic signature might form a relevant molecular mechanism through which fine particle air pollution exposure might affect placental processes and foetal development.

Short-term particulate matter exposure influences nasal microbiota in a population of healthy subjects.

BACKGROUND: Exposure to air pollutants, such as particulate matter (PM), represents a growing health problem. The aim of our study was to investigate whether PM could induce a dysbiosis in the nasal microbiota in terms of α-diversity and taxonomic composition. METHODS: We investigated structure and characteristics of the microbiota of 40 healthy subjects through metabarcoding analysis of the V3-V4 regions of the 16s rRNA gene. Exposure to PM10 and PM2.5 was assessed with a personal sampler worn for 24h before sample collection (Day -1) and with measurements from monitoring stations (from Day -2 to Day -7). RESULTS: We found an inverse association between PM10 and PM2.5 levels of the 3rd day preceding sampling (Day -3) and α-diversity indices (Chao1, Shannon and PD_whole_tree). Day -3 PM was inversely associated also with the majority of analyzed taxa, except for Moraxella, which showed a positive association. In addition, subjects showed different structural profiles identifying two groups: one characterized by an even community and another widely dominated by the Moraxella genus. CONCLUSIONS: Our findings support the role of PM exposure in influencing microbiota and altering the normal homeostasis within the bacterial community. Whether these alterations could have a role in disease development and/or exacerbation needs further research.

Blood pressure and expression of microRNAs in whole blood.

BACKGROUND: Blood pressure (BP) is a complex, multifactorial clinical outcome driven by genetic susceptibility, behavioral choices, and environmental factors. Many molecular mechanisms have been proposed for the pathophysiology of high BP even as its prevalence continues to grow worldwide, increasing morbidity and marking it as a major public health concern. To address this, we evaluated miRNA profiling in blood leukocytes as potential biomarkers of BP and BP-related risk factors. METHODS: The Beijing Truck Driver Air Pollution Study included 60 truck drivers and 60 office workers examined in 2008. On two days separated by 1-2 weeks, we examined three BP measures: systolic, diastolic, and mean arterial pressure measured at both pre- and post-work exams for blood NanoString nCounter miRNA profiles. We used covariate-adjusted linear mixed-effect models to examine associations between BP and increased miRNA expression in both pooled and risk factor-stratified analyses. RESULTS: Overall 43 miRNAs were associated with pre-work BP (FDR<0.05). In stratified analyses different but overlapping groups of miRNAs were associated with pre-work BP in truck drivers, high-BMI participants, and usual alcohol drinkers (FDR<0.05). Only four miRNAs were associated with post-work BP (FDR<0.05), in ever smokers. CONCLUSION: Our results suggest that many miRNAs were significantly associated with BP in subgroups exposed to known hypertension risk factors. These findings shed light on the underlying molecular mechanisms of BP, and may assist with the development of a miRNA panel for early detection of hypertension.

Epigenetics applied to epidemiology: investigating environmental factors and lifestyle influence on human health.

Epigenetics modifications, that include variations in DNA methylation, histone acetylation and micro RNA (miRNA) expression, co-operate together, influencing genome expression and function, in response to exogenous stimuli or exposures. Thus, epigenetic tools applied to epidemiology are useful in investigating, at the population level, the relationships between exposures to environmental, lifestyle, genetic, socioeconomic risk factors, and the epigenome, and/or specific health outcomes. But the choice of an appropriate study design and of valid epidemiological methods has a key role in determining the achievement of the study. This review summarises available evidence about the role of the most investigated epigenetic mechanisms in mediating lifestyle or environmental exposure effects on human health, considering the entire life-course, from in-utero to adulthood. Moreover, we illustrate the most important variables that should be properly considered when designing an epigenetic epidemiology study: the choice of an appropriate study design, a proper estimation of the required sample size, a correct biological sample selection, a validation strategy for epigenetics data, and an integrated exposure assessment methodology.

Bacterial and cytokine mixtures predict the length of gestation and are associated with miRNA expression in the cervix.

AIM: Bacterial vaginosis may lead to preterm birth through epigenetic programming of the inflammatory response, specifically via miRNA expression. METHODS: We quantified bacterial 16S rRNA, cytokine mRNA and 800 miRNA from cervical swabs obtained from 80 women at 16-19 weeks' gestation. We generated bacterial and cytokine indices using weighted quantile sum regression and examined associations with miRNA and gestational age at delivery. RESULTS & DISCUSSION: Each decile of the bacterial and cytokine indices was associated with shorter gestations (p < 0.005). The bacterial index was associated with miR-494, 371a, 4286, 185, 320e, 888 and 23a (p < 0.05). miR-494 remained significant after false discovery rate correction (q < 0.1). The cytokine index was associated with 27 miRNAs (p < 0.05; q < 0.01). CONCLUSION: Future investigation into the role of bacterial vaginosis- and inflammation-associated miRNA and preterm birth is warranted.

Epigenome-wide association study of body mass index, and the adverse outcomes of adiposity.

Approximately 1.5 billion people worldwide are overweight or affected by obesity, and are at risk of developing type 2 diabetes, cardiovascular disease and related metabolic and inflammatory disturbances. Although the mechanisms linking adiposity to associated clinical conditions are poorly understood, recent studies suggest that adiposity may influence DNA methylation, a key regulator of gene expression and molecular phenotype. Here we use epigenome-wide association to show that body mass index (BMI; a key measure of adiposity) is associated with widespread changes in DNA methylation (187 genetic loci with P < 1 × 10-7, range P = 9.2 × 10-8 to 6.0 × 10-46; n = 10,261 samples). Genetic association analyses demonstrate that the alterations in DNA methylation are predominantly the consequence of adiposity, rather than the cause. We find that methylation loci are enriched for functional genomic features in multiple tissues (P < 0.05), and show that sentinel methylation markers identify gene expression signatures at 38 loci (P < 9.0 × 10-6, range P = 5.5 × 10-6 to 6.1 × 10-35, n = 1,785 samples). The methylation loci identify genes involved in lipid and lipoprotein metabolism, substrate transport and inflammatory pathways. Finally, we show that the disturbances in DNA methylation predict future development of type 2 diabetes (relative risk per 1 standard deviation increase in methylation risk score: 2.3 (2.07-2.56); P = 1.1 × 10-54). Our results provide new insights into the biologic pathways influenced by adiposity, and may enable development of new strategies for prediction and prevention of type 2 diabetes and other adverse clinical consequences of obesity.

DNA methylation changes in Mexican children exposed to arsenic from two historic mining areas in San Luis potosí.

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.

Titanium and Zirconium Levels Are Associated with Changes in MicroRNAs Expression: Results from a Human Cross-Sectional Study on Obese Population.

OBJECTIVES: In this study on 90 individuals we aimed at evaluating the microRNAs (miRNAs) expression profile associated with personal levels of Titanium (Ti) and Zirconium (Zr) traced in hair samples. Ti and Zr materials are broadly used for dental implants but the biological reactions triggered by a long term presence of these materials in the oral cavity still need to be assessed. MiRNAs are mechanisms that need to be investigated as they play a fundamental role in the control of gene expression following external stimuli and contribute to a wide range of pathophysiological processes. METHODS: Using the TaqMan® Low-Density Array, we assessed the expression levels of 377 human miRNAs in peripheral blood of 90 subjects. Hair samples were analyzed for Ti and Zr content using Inductively Coupled Plasma-Mass Spectrometry. We performed multivariable regression analysis to investigate the effects of Ti and Zr exposure on miRNA expression levels. We used the Ingenuity Pathway Analysis (IPA) software to explore the functional role of the investigated miRNAs and the related target genes. RESULTS: Seven miRNAs (miR-99b, miR-142-5p, miR-152, miR-193a-5p, miR-323-3p, miR-335, miR-494) resulted specifically associated with Zr levels. The functional target analysis showed that miRNAs are involved in mechanisms such as inflammation, skeletal and connective tissue disorders. CONCLUSIONS: Our data suggest that Zr is more bioactive than Ti and show that miRNAs are relevant molecular mechanisms sensitive to Zr exposure.

Genome-wide DNA methylation study in human placenta identifies novel loci associated with maternal smoking during pregnancy.

BACKGROUND: We conducted an epigenome-wide association study (EWAS) of DNA methylation in placenta in relation to maternal tobacco smoking during pregnancy and examined whether smoking-induced changes lead to low birthweight. METHODS: DNA methylation in placenta was measured using the Illumina HumanMethylation450 BeadChip in 179 participants from the INfancia y Medio Ambiente (INMA) birth cohort. Methylation levels across 431 311 CpGs were tested for differential methylation between smokers and non-smokers in pregnancy. We took forward three top-ranking loci for further validation and replication by bisulfite pyrosequencing using data of 248 additional participants of the INMA cohort. We examined the association of methylation at smoking-associated loci with birthweight by applying a mediation analysis and a two-sample Mendelian randomization approach. RESULTS: Fifty CpGs were differentially methylated in placenta between smokers and non-smokers during pregnancy [false discovery rate (FDR) < 0.05]. We validated and replicated differential methylation at three top-ranking loci: cg27402634 located between LINC00086 and LEKR1, a gene previously related to birthweight in genome-wide association studies; cg20340720 (WBP1L); and cg25585967 and cg12294026 (TRIO). Dose-response relationships with maternal urine cotinine concentration during pregnancy were confirmed. Differential methylation at cg27402634 explained up to 36% of the lower birthweight in the offspring of smokers (Sobel P-value < 0.05). A two-sample Mendelian randomization analysis provided evidence that decreases in methylation levels at cg27402634 lead to decreases in birthweight. CONCLUSIONS: We identified novel loci differentially methylated in placenta in relation to maternal smoking during pregnancy. Adverse effects of maternal smoking on birthweight of the offspring may be mediated by alterations in the placental methylome.

Extracellular vesicle-driven information mediates the long-term effects of particulate matter exposure on coagulation and inflammation pathways.

BACKGROUND: Continuous exposure to particulate air pollution (PM) is a serious worldwide threat to public health as it coherently links with increased morbidity and mortality of cardiorespiratory diseases (CRD), and of type 2 diabetes (T2D). Extracellular vesicles (EVs) are circular plasma membrane fragments released from human cells that transfer microRNAs between tissues. In the present work it was explored the hypothesis that EVs with their encapsulated microRNAs (EVmiRNAs) contents might mediate PM effects by triggering key pathways in CRD and T2D. METHODS: Expression of EVmiRNAs analyzed by real-time PCR was correlated with oxidative stress, coagulation and inflammation markers, from healthy steel plant workers (n=55) with a well-characterized exposure to PM and PM-associated metals. All p-values were adjusted for multiple comparisons. In-silico Ingenuity Pathway Analysis (IPA) was performed to identify biological pathways regulated by PM-associated EVmiRNAs. RESULTS: Increased expression in 17 EVmiRNAs is associated with PM and metal exposure (p<0.01). Mir-196b that tops the list, being related to 9 different metals, is fundamental in insulin biosynthesis, however three (miR-302b, miR-200c, miR-30d) out of these 17 EVmiRNAs are in turn also related to disruptions (p<0.01) in inflammatory and coagulation markers. CONCLUSIONS: The study's findings support the hypothesis that adverse cardiovascular and metabolic effects stemming from inhalation exposures in particular to PM metallic component may be mediated by EVmiRNAs that target key factors in the inflammation, coagulation and glucose homeostasis pathways.

Hydroquinone induces DNA hypomethylation-independent overexpression of retroelements in human leukemia and hematopoietic stem cells.

Hydroquinone (HQ) is an important benzene-derived metabolite associated with acute myelogenous leukemia risk. Although altered DNA methylation has been reported in both benzene-exposed human subjects and HQ-exposed cultured cells, the inventory of benzene metabolite effects on the epigenome is only starting to be established. In this study, we used a monocytic leukemia cell line (THP-1) and hematopoietic stem cells (HSCs) from cord blood to investigate the effects of HQ treatment on the expression of the three most important families of retrotransposons in the human genome: LINE-1, Alu and Endogenous retroviruses (HERVs), that are normally subjected to tight epigenetic silencing. We found a clear tendency towards increased retrotransposon expression in response to HQ exposure, more pronounced in the case of LINE-1 and HERV. Such a partial loss of silencing, however, was generally not associated with HQ-induced DNA hypomethylation. On the other hand, retroelement derepression was also observed in the same cells in response to the hypomethylating agent decitabine. These observations suggest the existence of different types of epigenetic switches operating at human retroelements, and point to retroelement activation in response to benzene-derived metabolites as a novel factor deserving attention in benzene carcinogenesis studies.

MicroRNAs are associated with blood-pressure effects of exposure to particulate matter: Results from a mediated moderation analysis.

AIMS: Exposure to particulate air pollution is associated with increased blood pressure (BP), a well-established risk factor for cardiovascular disease. To elucidate the mechanisms underlying this relationship, we investigated whether the effects of particulate matter of less than 10µm in aerodynamic diameter (PM10) on BP are mediated by microRNAs. METHODS AND RESULTS: We recruited 90 obese individuals and we assessed their PM10 exposure 24 and 48h before the recruitment day. We performed multivariate linear regression models to investigate the effects of PM10 on BP. Using the TaqMan® Low-Density Array, we experimentally evaluated and technically validated the expression levels of 377 human miRNAs in peripheral blood. We developed a mediated moderation analysis to estimate the proportion of PM10 effects on BP that was mediated by miRNA expression. PM10 exposure 24 and 48h before the recruitment day was associated with increased systolic BP (ß=1.22mmHg, P=0.019; ß=1.24mmHg, P=0.019, respectively) and diastolic BP (ß=0.67mmHg, P=0.044; ß=0.91mmHg, P=0.007, respectively). We identified nine miRNAs associated with PM10 levels 48h after exposure. A conditional indirect effect (CIE=-0.1431) of PM10 on diastolic BP, which was mediated by microRNA-101, was found in individuals with lower values of mean body mass index. CONCLUSIONS: Our data provide evidence that miRNAs are a molecular mechanism underlying the BP-related effects of air pollution exposure, and indicate miR-101 as epigenetic mechanism to be further investigated.

Prenatal exposure to mixtures of xenoestrogens and genome-wide DNA methylation in human placenta.

BACKGROUND: In utero exposure to xenostrogens may modify the epigenome. We explored the association of prenatal exposure to mixtures of xenoestrogens and genome-wide placental DNA methylation. MATERIALS & METHODS: Sex-specific associations between methylation changes in placental DNA by doubling the concentration of TEXB-alpha exposure were evaluated by robust multiple linear regression. Two CpG sites were selected for validation and replication in additional male born placentas. RESULTS: No significant associations were found, although the top significant CpGs in boys were located in the LRPAP1, HAGH, PPARGC1B, KCNQ1 and KCNQ1DN genes, previously associated to birth weight, Type 2 diabetes, obesity or steroid hormone signaling. Neither technical validation nor biological replication of the results was found in boys for LRPAP and PPARGC1B. CONCLUSION: Some suggestive genes were differentially methylated in boys in relation to prenatal xenoestrogen exposure, but our initial findings could not be validated or replicated.

Particulate Air Pollution Exposure and Expression of Viral and Human MicroRNAs in Blood: The Beijing Truck Driver Air Pollution Study.

BACKGROUND: MicroRNAs (miRNAs) are post-transcriptional gene suppressors and potential mediators of environmental effects. In addition to human miRNAs, viral miRNAs expressed from latent viral sequences are detectable in human cells. OBJECTIVE: In a highly exposed population in Beijing, China, we evaluated the associations of particulate air pollution exposure on blood miRNA profiles. METHODS: The Beijing Truck Driver Air Pollution Study (BTDAS) included 60 truck drivers and 60 office workers. We investigated associations of short-term air pollution exposure, using measures of personal PM2.5 (particulate matter ≤ 2.5 µm) and elemental carbon (EC), and ambient PM10 (≤ 10 µm), with blood NanoString nCounter miRNA profiles at two exams separated by 1-2 weeks. RESULTS: No miRNA was significantly associated with personal PM2.5 at a false discovery rate (FDR) of 20%. Short-term ambient PM10 was associated with the expression of 12 miRNAs in office workers only (FDR < 20%). Short-term EC was associated with differential expression of 46 human and 7 viral miRNAs, the latter including 3 and 4 viral miRNAs in office workers and truck drivers, respectively. EC-associated miRNAs differed between office workers and truck drivers with significant effect modification by occupational group. Functional interaction network analysis suggested enriched cellular proliferation/differentiation pathways in truck drivers and proinflammation pathways in office workers. CONCLUSIONS: Short-term EC exposure was associated with the expression of human and viral miRNAs that may influence immune responses and other biological pathways. Associations between EC exposure and viral miRNA expression suggest that latent viral miRNAs are potential mediators of air pollution-associated health effects. PM2.5/PM10 exposures showed no consistent relationships with miRNA expression.

Altered miRNA expression in the cervix during pregnancy associated with lead and mercury exposure.

AIM: Toxic metals including lead and mercury are associated with adverse pregnancy outcomes. This study aimed to assess the association between miRNA expression in the cervix during pregnancy with lead and mercury levels. MATERIALS & METHODS: We obtained cervical swabs from pregnant women (n = 60) and quantified cervical miRNA expression. Women's blood lead, bone lead and toenail mercury levels were analyzed. We performed linear regression to examine the association between metal levels and expression of 74 miRNAs adjusting for covariates. RESULTS: Seventeen miRNAs were negatively associated with toenail mercury levels, and tibial bone lead levels were associated with decreased expression of miR-575 and miR-4286. CONCLUSION: The findings highlight miRNAs in the human cervix as novel responders to maternal chemical exposure during pregnancy.

Epigenome-wide association of DNA methylation markers in peripheral blood from Indian Asians and Europeans with incident type 2 diabetes: a nested case-control study.

BACKGROUND: Indian Asians, who make up a quarter of the world's population, are at high risk of developing type 2 diabetes. We investigated whether DNA methylation is associated with future type 2 diabetes incidence in Indian Asians and whether differences in methylation patterns between Indian Asians and Europeans are associated with, and could be used to predict, differences in the magnitude of risk of developing type 2 diabetes. METHODS: We did a nested case-control study of DNA methylation in Indian Asians and Europeans with incident type 2 diabetes who were identified from the 8-year follow-up of 25 372 participants in the London Life Sciences Prospective Population (LOLIPOP) study. Patients were recruited between May 1, 2002, and Sept 12, 2008. We did epigenome-wide association analysis using samples from Indian Asians with incident type 2 diabetes and age-matched and sex-matched Indian Asian controls, followed by replication testing of top-ranking signals in Europeans. For both discovery and replication, DNA methylation was measured in the baseline blood sample, which was collected before the onset of type 2 diabetes. Epigenome-wide significance was set at p<1 × 10(-7). We compared methylation levels between Indian Asian and European controls without type 2 diabetes at baseline to estimate the potential contribution of DNA methylation to increased risk of future type 2 diabetes incidence among Indian Asians. FINDINGS: 1608 (11·9%) of 13 535 Indian Asians and 306 (4·3%) of 7066 Europeans developed type 2 diabetes over a mean of 8·5 years (SD 1·8) of follow-up. The age-adjusted and sex-adjusted incidence of type 2 diabetes was 3·1 times (95% CI 2·8-3·6; p<0·0001) higher among Indian Asians than among Europeans, and remained 2·5 times (2·1-2·9; p<0·0001) higher after adjustment for adiposity, physical activity, family history of type 2 diabetes, and baseline glycaemic measures. The mean absolute difference in methylation level between type 2 diabetes cases and controls ranged from 0·5% (SD 0·1) to 1·1% (0·2). Methylation markers at five loci were associated with future type 2 diabetes incidence; the relative risk per 1% increase in methylation was 1·09 (95% CI 1·07-1·11; p=1·3 × 10(-17)) for ABCG1, 0·94 (0·92-0·95; p=4·2 × 10(-11)) for PHOSPHO1, 0·94 (0·92-0·96; p=1·4 × 10(-9)) for SOCS3, 1·07 (1·04-1·09; p=2·1 × 10(-10)) for SREBF1, and 0·92 (0·90-0·94; p=1·2 × 10(-17)) for TXNIP. A methylation score combining results for the five loci was associated with future type 2 diabetes incidence (relative risk quartile 4 vs quartile 1 3·51, 95% CI 2·79-4·42; p=1·3 × 10(-26)), and was independent of established risk factors. Methylation score was higher among Indian Asians than Europeans (p=1 × 10(-34)). INTERPRETATION: DNA methylation might provide new insights into the pathways underlying type 2 diabetes and offer new opportunities for risk stratification and prevention of type 2 diabetes among Indian Asians. FUNDING: The European Union, the UK National Institute for Health Research, the Wellcome Trust, the UK Medical Research Council, Action on Hearing Loss, the UK Biotechnology and Biological Sciences Research Council, the Oak Foundation, the Economic and Social Research Council, Helmholtz Zentrum Munchen, the German Research Center for Environmental Health, the German Federal Ministry of Education and Research, the German Center for Diabetes Research, the Munich Center for Health Sciences, the Ministry of Science and Research of the State of North Rhine-Westphalia, and the German Federal Ministry of Health.

microRNA expression in the cervix during pregnancy is associated with length of gestation.

Preterm birth is a leading cause of infant mortality and can lead to poor life-long health and adverse neurodevelopmental outcomes. The pathophysiologic mechanisms that precede preterm labor remain elusive, and the role that epigenetic phenomena play is largely unstudied. The objective of this study was to assess the association between microRNA (miRNA) expression levels in cervical cells obtained from swabs collected during pregnancy and the length of gestation. We analyzed cervical samples obtained between 16 and 19 weeks of gestation from 53 women in a prospective cohort from Mexico City, and followed them until delivery. Cervical miRNA was extracted and expression was quantified using the NanoString nCounter Analysis System. Linear regression models were used to examine the association between miRNA expression levels and gestational age at delivery, adjusted for maternal age, education, parity, body mass index, smoke exposure, and inflammation assessed on a Papanicolaou smear. We identified 6 miRNAs that were significantly associated with gestational age at the time of delivery, including miR-21, 30e, 142, 148b, 29b, and 223. Notably, per each doubling in miR-21 expression, gestations were 0.9 (95% CI: 0.2-1.5) days shorter on average (P = 0.009). Per each doubling in miR-30e, 142, 148b, 29b, and 223 expression, gestations were shorter by 1.0 to 1.6 days. The predicted targets of the miRNAs were enriched for molecules involved in DNA replication and inflammatory processes. The levels of specific miRNAs in the human cervix during pregnancy are predictive of gestational age at delivery, and should be validated in future studies as potential biomarkers of preterm birth risk.

Susceptibility to particle health effects, miRNA and exosomes: rationale and study protocol of the SPHERE study.

BACKGROUND: Despite epidemiological findings showing increased air pollution related cardiovascular diseases (CVD), the knowledge of the involved molecular mechanisms remains moderate or weak. Particulate matter (PM) produces a local strong inflammatory reaction in the pulmonary environment but there is no final evidence that PM physically enters and deposits in blood vessels. Extracellular vesicles (EVs) and their miRNA cargo might be the ideal candidate to mediate the effects of PM, since they could be potentially produced by the respiratory system, reach the systemic circulation and lead to the development of cardiovascular effects.The SPHERE ("Susceptibility to Particle Health Effects, miRNAs and Exosomes") project was granted by ERC-2011-StG 282413, to examine possible molecular mechanisms underlying the effects of PM exposure in relation to health outcomes. METHODS/DESIGN: The study population will include 2000 overweight (25 < BMI < 30 kg/cm2) or obese (BMI ≥ 30 kg/cm2) subjects presenting at the Center for Obesity and Work (Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy).Each subject donates blood, urine and hair samples. Extensive epidemiological and clinical data are collected. Exposure to PM is assigned to each subject using both daily PM10 concentration series from air quality monitors and pollutant levels estimated by the FARM (Flexible air Quality Regional Model) modelling system and elaborated by the Regional Environmental Protection Agency.The recruitment period started in September 2010 and will continue until 2015. At December 31, 2013 we recruited 1250 subjects, of whom 87% lived in the province of Milan.Primary study outcomes include cardiometabolic and respiratory health effects. The main molecular mechanism we are investigating focuses on EV-associated microRNAs. DISCUSSION: SPHERE is the first large study aimed to explore EVs as a novel potential mechanism of how air pollution exposure acts in a highly susceptible population. The rigorous study design, the availability of banked biological samples and the potential to integrate epidemiological, clinical and molecular data will also furnish a powerful base for investigating different complementary molecular mechanisms. Our findings, if confirmed, could lead to the identification of potentially reversible alterations that might be considered as possible targets for new diagnostic and therapeutic interventions.