| 1. |
- Murray, Christopher J. L., et al.
(författare)
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Population and fertility by age and sex for 195 countries and territories, 1950–2017: a systematic analysis for the Global Burden of Disease Study 2017
- 2018
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Ingår i: The Lancet. - 1474-547X .- 0140-6736. ; 392:10159, s. 1995-2051
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Tidskriftsartikel (refereegranskat)abstract
- Background: Population estimates underpin demographic and epidemiological research and are used to track progress on numerous international indicators of health and development. To date, internationally available estimates of population and fertility, although useful, have not been produced with transparent and replicable methods and do not use standardised estimates of mortality. We present single-calendar year and single-year of age estimates of fertility and population by sex with standardised and replicable methods. Methods: We estimated population in 195 locations by single year of age and single calendar year from 1950 to 2017 with standardised and replicable methods. We based the estimates on the demographic balancing equation, with inputs of fertility, mortality, population, and migration data. Fertility data came from 7817 location-years of vital registration data, 429 surveys reporting complete birth histories, and 977 surveys and censuses reporting summary birth histories. We estimated age-specific fertility rates (ASFRs; the annual number of livebirths to women of a specified age group per 1000 women in that age group) by use of spatiotemporal Gaussian process regression and used the ASFRs to estimate total fertility rates (TFRs; the average number of children a woman would bear if she survived through the end of the reproductive age span [age 10–54 years] and experienced at each age a particular set of ASFRs observed in the year of interest). Because of sparse data, fertility at ages 10–14 years and 50–54 years was estimated from data on fertility in women aged 15–19 years and 45–49 years, through use of linear regression. Age-specific mortality data came from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017 estimates. Data on population came from 1257 censuses and 761 population registry location-years and were adjusted for underenumeration and age misreporting with standard demographic methods. Migration was estimated with the GBD Bayesian demographic balancing model, after incorporating information about refugee migration into the model prior. Final population estimates used the cohort-component method of population projection, with inputs of fertility, mortality, and migration data. Population uncertainty was estimated by use of out-of-sample predictive validity testing. With these data, we estimated the trends in population by age and sex and in fertility by age between 1950 and 2017 in 195 countries and territories. Findings: From 1950 to 2017, TFRs decreased by 49·4% (95% uncertainty interval [UI] 46·4–52·0). The TFR decreased from 4·7 livebirths (4·5–4·9) to 2·4 livebirths (2·2–2·5), and the ASFR of mothers aged 10–19 years decreased from 37 livebirths (34–40) to 22 livebirths (19–24) per 1000 women. Despite reductions in the TFR, the global population has been increasing by an average of 83·8 million people per year since 1985. The global population increased by 197·2% (193·3–200·8) since 1950, from 2·6 billion (2·5–2·6) to 7·6 billion (7·4–7·9) people in 2017; much of this increase was in the proportion of the global population in south Asia and sub-Saharan Africa. The global annual rate of population growth increased between 1950 and 1964, when it peaked at 2·0%; this rate then remained nearly constant until 1970 and then decreased to 1·1% in 2017. Population growth rates in the southeast Asia, east Asia, and Oceania GBD super-region decreased from 2·5% in 1963 to 0·7% in 2017, whereas in sub-Saharan Africa, population growth rates were almost at the highest reported levels ever in 2017, when they were at 2·7%. The global average age increased from 26·6 years in 1950 to 32·1 years in 2017, and the proportion of the population that is of working age (age 15–64 years) increased from 59·9% to 65·3%. At the national level, the TFR decreased in all countries and territories between 1950 and 2017; in 2017, TFRs ranged from a low of 1·0 livebirths (95% UI 0·9–1·2) in Cyprus to a high of 7·1 livebirths (6·8–7·4) in Niger. The TFR under age 25 years (TFU25; number of livebirths expected by age 25 years for a hypothetical woman who survived the age group and was exposed to current ASFRs) in 2017 ranged from 0·08 livebirths (0·07–0·09) in South Korea to 2·4 livebirths (2·2–2·6) in Niger, and the TFR over age 30 years (TFO30; number of livebirths expected for a hypothetical woman ageing from 30 to 54 years who survived the age group and was exposed to current ASFRs) ranged from a low of 0·3 livebirths (0·3–0·4) in Puerto Rico to a high of 3·1 livebirths (3·0–3·2) in Niger. TFO30 was higher than TFU25 in 145 countries and territories in 2017. 33 countries had a negative population growth rate from 2010 to 2017, most of which were located in central, eastern, and western Europe, whereas population growth rates of more than 2·0% were seen in 33 of 46 countries in sub-Saharan Africa. In 2017, less than 65% of the national population was of working age in 12 of 34 high-income countries, and less than 50% of the national population was of working age in Mali, Chad, and Niger. Interpretation: Population trends create demographic dividends and headwinds (ie, economic benefits and detriments) that affect national economies and determine national planning needs. Although TFRs are decreasing, the global population continues to grow as mortality declines, with diverse patterns at the national level and across age groups. To our knowledge, this is the first study to provide transparent and replicable estimates of population and fertility, which can be used to inform decision making and to monitor progress. Funding: Bill & Melinda Gates Foundation.
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| 2. |
- Acevedo, Nathalie, et al.
(författare)
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DNA Methylation Levels in Mononuclear Leukocytes from the Mother and Her Child Are Associated with IgE Sensitization to Allergens in Early Life
- 2021
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Ingår i: International Journal of Molecular Sciences. - : MDPI AG. - 1661-6596 .- 1422-0067. ; 22:2
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Tidskriftsartikel (refereegranskat)abstract
- DNA methylation changes may predispose becoming IgE-sensitized to allergens. We analyzed whether DNA methylation in peripheral blood mononuclear cells (PBMC) is associated with IgE sensitization at 5 years of age (5Y). DNA methylation was measured in 288 PBMC samples from 74 mother/child pairs from the birth cohort ALADDIN (Assessment of Lifestyle and Allergic Disease During INfancy) using the HumanMethylation450BeadChip (Illumina). PBMCs were obtained from the mothers during pregnancy and from their children in cord blood, at 2 years and 5Y. DNA methylation levels at each time point were compared between children with and without IgE sensitization to allergens at 5Y. For replication, CpG sites associated with IgE sensitization in ALADDIN were evaluated in whole blood DNA of 256 children, 4 years old, from the BAMSE (Swedish abbreviation for Children, Allergy, Milieu, Stockholm, Epidemiology) cohort. We found 34 differentially methylated regions (DMRs) associated with IgE sensitization to airborne allergens and 38 DMRs associated with sensitization to food allergens in children at 5Y (Sidak p <= 0.05). Genes associated with airborne sensitization were enriched in the pathway of endocytosis, while genes associated with food sensitization were enriched in focal adhesion, the bacterial invasion of epithelial cells, and leukocyte migration. Furthermore, 25 DMRs in maternal PBMCs were associated with IgE sensitization to airborne allergens in their children at 5Y, which were functionally annotated to the mTOR (mammalian Target of Rapamycin) signaling pathway. This study supports that DNA methylation is associated with IgE sensitization early in life and revealed new candidate genes for atopy. Moreover, our study provides evidence that maternal DNA methylation levels are associated with IgE sensitization in the child supporting early in utero effects on atopy predisposition.
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| 3. |
- Delgado, Luis F., et al.
(författare)
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BAGS-Shiny: a web-based interactive tool for exploring the Baltic Sea microbial gene set
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Biome-specific gene catalogues have been recovered for many environments using shotgun metagenomics, followed by assembly and gene calling on the assembled contigs. We recently proposed a novel mix-assembly strategy, combining individual and co-assembly approaches, and used this approach to assemble an extensive non-redundant gene set from 124 Baltic Sea metagenome samples. The Baltic Sea Gene Set (BAGS v1.1) comprises 66.53 million functionally and taxonomically annotated genes. To enable interactive exploration of this gene catalogue we have developed an RShiny application, BAGS-Shiny, that allows users to perform searches by sequence similarity (BLAST) and/or taxonomic and functional annotation. The gene catalogue and web application will serve as valuable tools for exploring microbial gene functions in brackish ecosystems. In addition, we here make available a pipeline to create gene catalogues based on the mix-assembly approach.
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| 4. |
- Eriksson Ström, Jonas, et al.
(författare)
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Chronic obstructive pulmonary disease is associated with epigenome-wide differential methylation in BAL lung cells
- 2022
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Ingår i: American Journal of Respiratory Cell and Molecular Biology. - : American Thoracic Society. - 1044-1549 .- 1535-4989. ; 66:6, s. 638-647
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Tidskriftsartikel (refereegranskat)abstract
- DNA methylation patterns in chronic pulmonary obstructive disease (COPD) might offer new insights into disease pathogenesis. To assess methylation profiles in the main COPD target organ, we performed an epigenome-wide association study on BAL cells. Bronchoscopies were performed in 18 subjects with COPD and 15 control subjects (ex- and current smokers). DNA methylation was measured using the Illumina MethylationEPIC BeadChip Kit, covering more than 850,000 CpGs. Differentially methylated positions (DMPs) were examined for 1) enrichment in pathways and functional gene relationships using the Kyoto Encyclopedia of Genes and Genomes and Gene Ontology, 2) accelerated aging using Horvath's epigenetic clock, 3) correlation with gene expression, and 4) colocalization with genetic variation. We found 1,155 Bonferroni-significant (P < 6.74 × 10-8) DMPs associated with COPD, many with large effect sizes. Functional analysis identified biologically plausible pathways and gene relationships, including enrichment for transcription factor activity. Strong correlation was found between DNA methylation and chronological age but not between COPD and accelerated aging. For 79 unique DMPs, DNA methylation correlated significantly with gene expression in BAL cells. Thirty-nine percent of DMPs were colocalized with COPD-associated SNPs. To the best of our knowledge, this is the first epigenome-wide association study of COPD on BAL cells, and our analyses revealed many differential methylation sites. Integration with mRNA data showed a strong functional readout for relevant genes, identifying sites where DNA methylation might directly affect expression. Almost half of DMPs were colocated with SNPs identified in previous genome-wide association studies of COPD, suggesting joint genetic and epigenetic pathways related to disease.
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| 5. |
- Klevebro, Susanna, et al.
(författare)
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Arachidonic acid and docosahexaenoic acid levels correlate with the inflammation proteome in extremely preterm infants
- 2024
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Ingår i: Clinical Nutrition. - : Elsevier BV. - 0261-5614 .- 1532-1983. ; 43:5, s. 1162-1170
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Tidskriftsartikel (refereegranskat)abstract
- Background & aim: Clinical trials supplementing the long-chain polyunsaturated fatty acids (LCPUFAs) docosahexaenoic acid (DHA) and arachidonic acid (AA) to preterm infants have shown positive effects on inflammation-related morbidities, but the molecular mechanisms underlying these effects are not fully elucidated. This study aimed to determine associations between DHA, AA, and inflammation-related proteins during the neonatal period in extremely preterm infants. Methods: A retrospective exploratory study of infants (n = 183) born below 28 weeks gestation from the Mega Donna Mega trial, a randomized multicenter trial designed to study the effect of DHA and AA on retinopathy of prematurity. Serial serum samples were collected after birth until postnatal day 100 (median 7 samples per infant) and analyzed for phospholipid fatty acids and proteins using targeted proteomics covering 538 proteins. Associations over time between LCPUFAs and proteins were explored using mixed effect modeling with splines, including an interaction term for time, and adjusted for gestational age, sex, and center. Results: On postnatal day one, 55 proteins correlated with DHA levels and 10 proteins with AA levels. Five proteins were related to both fatty acids, all with a positive correlation. Over the first 100 days after birth, we identified 57 proteins to be associated with DHA and/or AA. Of these proteins, 41 (72%) related to inflammation. Thirty-eight proteins were associated with both fatty acids and the overall direction of association did not differ between DHA and AA, indicating that both LCPUFAs similarly contribute to up- and down-regulation of the preterm neonate inflammatory proteome. Primary examples of this were the inflammation-modulating cytokines IL-6 and CCL7, both being negatively related to levels of DHA and AA in the postnatal period. Conclusions: This study supports postnatal non-antagonistic and potentially synergistic effects of DHA and AA on the inflammation proteome in preterm infants, indicating that supplementation with both fatty acids may contribute to limiting the disease burden in this vulnerable population. Clinical registration number: ClinicalTrials.gov (NCT03201588).
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| 6. |
- Klevebro, Susanna, et al.
(författare)
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Risk of SARS-CoV-2 exposure among hospital healthcare workers in relation to patient contact and type of care
- 2021
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Ingår i: Scandinavian Journal of Public Health. - : SAGE Publications. - 1403-4948 .- 1651-1905. ; 49:7, s. 707-712
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Tidskriftsartikel (refereegranskat)abstract
- We aimed to assess prevalence of IgG antibodies to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and factors associated with seropositivity in a large cohort of healthcare workers (HCWs). Methods: From 11 May until 11 June 2020, 3981 HCWs at a large Swedish emergency care hospital provided serum samples and questionnaire data. Presence of IgG antibodies to SARS-CoV-2 was measured as an indicator of SARS-CoV-2 exposure. Results: The total seroprevalence was 18% and increased during the study period. Among the seropositive HCWs, 11% had been entirely asymptomatic. Participants who worked with COVID-19 patients had higher odds for seropositivity: adjusted odds ratio 1.96 (95% confidence intervals 1.59–2.42). HCWs from three of the departments managing COVID-19 patients had significantly higher seroprevalences, whereas the prevalence among HCWs from the intensive care unit (also managing COVID-19 patients) was significantly lower. Conclusions: HCWs in contact with SARS-CoV-2 infected patients had a variable, but on average higher, likelihood for SARS-CoV-2 infections.
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| 7. |
- Merid, Simon Kebede, et al.
(författare)
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Distinguishing between driver and passenger mutations in individual cancer genomes by network enrichment analysis
- 2014
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Ingår i: BMC Bioinformatics. - : Springer Science and Business Media LLC. - 1471-2105. ; 15, s. 308-
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Tidskriftsartikel (refereegranskat)abstract
- Background: In somatic cancer genomes, delineating genuine driver mutations against a background of multiple passenger events is a challenging task. The difficulty of determining function from sequence data and the low frequency of mutations are increasingly hindering the search for novel, less common cancer drivers. The accumulation of extensive amounts of data on somatic point and copy number alterations necessitates the development of systematic methods for driver mutation analysis. Results: We introduce a framework for detecting driver mutations via functional network analysis, which is applied to individual genomes and does not require pooling multiple samples. It probabilistically evaluates 1) functional network links between different mutations in the same genome and 2) links between individual mutations and known cancer pathways. In addition, it can employ correlations of mutation patterns in pairs of genes. The method was used to analyze genomic alterations in two TCGA datasets, one for glioblastoma multiforme and another for ovarian carcinoma, which were generated using different approaches to mutation profiling. The proportions of drivers among the reported de novo point mutations in these cancers were estimated to be 57.8% and 16.8%, respectively. The both sets also included extended chromosomal regions with synchronous duplications or losses of multiple genes. We identified putative copy number driver events within many such segments. Finally, we summarized seemingly disparate mutations and discovered a functional network of collagen modifications in the glioblastoma. In order to select the most efficient network for use with this method, we used a novel, ROC curve-based procedure for benchmarking different network versions by their ability to recover pathway membership. Conclusions: The results of our network-based procedure were in good agreement with published gold standard sets of cancer genes and were shown to complement and expand frequency-based driver analyses. On the other hand, three sequence-based methods applied to the same data yielded poor agreement with each other and with our results. We review the difference in driver proportions discovered by different sequencing approaches and discuss the functional roles of novel driver mutations. The software used in this work and the global network of functional couplings are publicly available at http://research.scilifelab.se/andrej_alexeyenko/downloads.html.
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| 8. |
- Merid, Simon Kebede, et al.
(författare)
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Epigenome-wide meta-analysis of blood DNA methylation in newborns and children identifies numerous loci related to gestational age
- 2020
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Ingår i: Genome Medicine. - Stockholm : Karolinska Institutet, Dept of Clinical Science and Education, Södersjukhuset. - 1756-994X.
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Tidskriftsartikel (refereegranskat)abstract
- Background: Preterm birth and shorter duration of pregnancy are associated with increased morbidity in neonatal and later life. As the epigenome is known to have an important role during fetal development, we investigated associations between gestational age and blood DNA methylation in children. Methods: We performed meta-analysis of Illumina's HumanMethylation450-array associations between gestational age and cord blood DNA methylation in 3648 newborns from 17 cohorts without common pregnancy complications, induced delivery or caesarean section. We also explored associations of gestational age with DNA methylation measured at 4-18 years in additional pediatric cohorts. Follow-up analyses of DNA methylation and gene expression correlations were performed in cord blood. DNA methylation profiles were also explored in tissues relevant for gestational age health effects: fetal brain and lung. Results: We identified 8899 CpGs in cord blood that were associated with gestational age (range 27-42 weeks), at Bonferroni significance, P < 1.06 × 10- 7, of which 3343 were novel. These were annotated to 4966 genes. After restricting findings to at least three significant adjacent CpGs, we identified 1276 CpGs annotated to 325 genes. Results were generally consistent when analyses were restricted to term births. Cord blood findings tended not to persist into childhood and adolescence. Pathway analyses identified enrichment for biological processes critical to embryonic development. Follow-up of identified genes showed correlations between gestational age and DNA methylation levels in fetal brain and lung tissue, as well as correlation with expression levels. Conclusions: We identified numerous CpGs differentially methylated in relation to gestational age at birth that appear to reflect fetal developmental processes across tissues. These findings may contribute to understanding mechanisms linking gestational age to health effects.
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| 9. |
- Merid, Simon Kebede, et al.
(författare)
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Integration of gene expression and DNA methylation identifies epigenetically controlled modules related to PM2.5 exposure
- 2020
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Ingår i: Environment International. - Stockholm : Karolinska Institutet, Dept of Clinical Science and Education, Södersjukhuset. - 0160-4120 .- 1873-6750.
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Tidskriftsartikel (refereegranskat)abstract
- Air pollution has been associated with adverse health effects across the life-course. Although underlying mechanisms are unclear, several studies suggested pollutant-induced changes in transcriptomic profiles. In this meta-analysis of transcriptome-wide association studies of 656 children and adolescents from three European cohorts participating in the MeDALL Consortium, we found two differentially expressed transcript clusters (FDR p < 0.05) associated with exposure to particulate matter < 2.5 µm in diameter (PM2.5) at birth, one of them mapping to the MIR1296 gene. Further, by integrating gene expression with DNA methylation using Functional Epigenetic Modules algorithms, we identified 9 and 6 modules in relation to PM2.5 exposure at birth and at current address, respectively (including NR1I2, MAPK6, TAF8 and SCARA3). In conclusion, PM2.5 exposure at birth was linked to differential gene expression in children and adolescents. Importantly, we identified several significant interactome hotspots of gene modules of relevance for complex diseases in relation to PM2.5 exposure.
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| 10. |
- Merid, Simon Kebede
(författare)
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Molecular signatures of early life exposures and complex diseases : applications using epigenetics and transcriptomics data
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Environmental exposures and early life stressors may influence developmental processes and have long-term health consequences, potentially mediated by molecular mechanisms such as epigenetic modifications. The most extensively studied epigenetic mechanism is DNA methylation, which has been proposed to constitute a link between genetic and environmental factors. Epigenetic patterns established early in life (already in utero) may affect how a gene is expressed throughout life, and thereby increase susceptibility to chronic disease. Other factors like genetics and repeated airway infections also influence disease risk. Chronic obstructive pulmonary disease (COPD) is a complex disease considered a major global health problem, with tobacco smoking being one of the main risk factors. The role that deoxyribonucleic acid (DNA) methylation might play in the pathogenesis of COPD has not been comprehensively studied. Bronchoalveolar lavage (BAL) cells from the airways and alveolar space are considered key targets for COPD. Peanut allergy is another complex disease – one of the most common food allergies and the leading cause of anaphylaxis among children. Peanut oral immunotherapy (pOIT) can lead to desensitization and tolerance, and combined treatment with anti-immunoglobulin E (IgE) using omalizumab may facilitate oral immunotherapy initiation. The mechanisms of oral immunotherapy-induced tolerance, including possible changes at the transcriptional level, are not well understood. The main aim of this thesis was to identify molecular signatures of early-life exposures, chronic respiratory disease, as well as allergy treatment responses. In Study I, the association between gestational age and DNA methylation patterns (at 5´-cytosine-phosphate-guanine-3´ sites, CpGs, across the genome) was investigated in newborns and older children from the large The Pregnancy And Childhood Epigenetics (PACE) consortium meta-analysis, including 11,000 participants in 26 independent cohorts. Changes in DNA methylation associated with gestational age were explored in additional pediatric cohorts at 4–18 years. The functional follow-up and correlation analyses between DNA methylation and gene expression were performed using cord blood. In addition, we evaluated DNA methylation profiles in other relevant tissues (fetal brain and lung) related to gestational age. We found numerous epigenome-wide differentially methylated CpGs related to gestational age at birth. Notably, many of the identified CpGs had not previously been associated with gestational age. Several CpGs affected the expression of nearby genes, displayed a strong functional link with human diseases, and were enriched in biological processes essential for fetal development. The epigenetic plasticity of fetal development across tissues was captured by many methylation sites. However, the majority of methylation levels underwent changes over time and stabilized after school age. In Study II, the impact of outdoor exposure to particles of less than 2.5 micrometers in size (PM2.5) at birth and current residential address on gene expression was explored in childhood and adolescence in the MeDALL consortium encompassing three European birth cohorts. In addition, the functional molecular patterns of PM2.5 exposure were evaluated by integrating protein-protein interaction and genome-wide gene expression with matched DNA methylation. We found evidence suggestive of gene signatures in children and adolescents associated with PM2.5 exposure at birth. However, the integration of multi-omics profiles revealed several epigenetic deregulation gene module interactome hotspots where both methylation and expression levels were affected by PM2.5 exposure at birth and current address. Some of the identified genes were associated with diseases known to be caused by or worsened by air pollution exposure. In Study III, the pivotal role of DNA methylation profiles in BAL cells primarily macrophages was assessed in relation to COPD status and smoking in adults, to gain a further understanding of the disease pathogenesis. Several CpGs were associated with COPD in BAL cells, across the epigenome. Many of the identified CpGs displayed a strong functional link with gene expression and pathways enriched in cancer, various types of cell junctions, and cyclic adenosine monophosphate (cAMP) and Rap1 signaling. Notably, almost half of the CpGs co-located in the proximity of COPD-associated single nucleotide polymorphisms, which suggests that both genetic and epigenetic mechanisms are of importance at certain loci. In Study IV, the blood gene expression profiles before, during, and after pOIT and Omalizumab (O, an anti-IgE monoclonal antibody) treatment were evaluated in adolescent patients with severe peanut allergy using high-throughput ribonucleic acid (RNA) sequencing. At the first two timepoints, baseline and pOIT start, we investigated if there was an effect of omalizumab treatment on gene expression. In addition, a longitudinal analysis was performed to evaluate the combined effect of pOIT with Omalizumab (pOIT+O). We also evaluated the overlap of pOIT+O-associated genes with genes associated with acute peanut allergic reactions in a previously published clinical study by Watson et al1. First, we showed that the blood gene expression of patients with peanut allergy was not altered by omalizumab treatment alone. However, the combined effect of pOIT+O showed up- and downregulation of several genes involved in T-cell functions and immune responses. Furthermore, comparing our findings with genes previously found to be affected during acute peanut allergic reactions suggested that pOIT+O may play a role in altering the same genes (in the opposite direction). In conclusion, we demonstrated that DNA methylation profiles are related to gestational age at birth. The identified methylation sites were linked to human diseases and are likely to be involved in biological processes essential for fetal development. Most of the methylation sites also affect expression of nearby genes and reflect epigenetic plasticity of fetal development across tissues. We highlighted the added value of multi-omics analyses in relation to information on PM2.5 exposure that may enhance the understanding of molecular mechanisms and biological responses induced by air pollutants. Moreover, we revealed COPD-associated methylation changes in macrophage-dense BAL cells with a strong functional link to different pathways and gene expression. Both genetic and epigenetic mechanisms play important roles at certain loci. We also provided insights into the transcriptome profiles during pOIT and combined treatment with omalizumab.
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