Most genetic variants associated with complex traits are hypothesized to regulate gene expression. To understand the genetics underlying gene expression variability, we characterized 14,324 RNA-sequencing samples from the Trans-Omics for Precision Medicine program and performed expression and splicing quantitative trait locus (e/sQTL) analyses in six tissues and cell types, including whole blood (n = 6454) and lung (n = 1291). We detected tens of thousands of secondary cis-e/sQTLs, showing that secondary cis-e/sQTL discovery remains unsaturated. We fine-mapped UK Biobank-derived genome-wide association study (GWAS) signals from 164 traits and identified e/sQTL colocalizations for 10,611 GWAS signals, including 7096 that colocalize with secondary e/sQTLs. Our results suggest that even larger e/sQTL analyses will uncover additional secondary e/sQTLs, further benefiting GWAS interpretation.

Pelvic organ prolapse (POP) is a common condition with poorly understood mechanisms. Metabolic endotoxemia and gut microbiome dysbiosis may impair connective tissue integrity, contributing to POP. We hypothesized that women with POP have a distinct gut microbiome and greater systemic inflammation than controls. This prospective cohort study enrolled patients undergoing hysterectomy for benign indications from February 2023 to February 2024. Stool, blood, and uterosacral ligament (USL) biopsies were collected. Gut microbiome composition, including alpha and beta diversity and differential abundance of bacterial taxa, was assessed. In addition, plasma inflammatory markers and histologic inflammation were also evaluated. Eighty-six patients were analyzed. Alpha diversity was higher in POP patients by observed features (p = 0.048) and increased with prolapse stage, but these associations did not persist after adjusting for age. Beta diversity showed no distinct patterns. Clostridia vadinBB60 group, Eubacteriales, and Rhodospirillales increased with advancing stage, persisting after age adjustment. Plasma lipopolysaccharide-binding protein (LBP) and histologic inflammation were significantly higher in POP patients, while lipopolysaccharide (LPS) and zonulin were comparable. Women with POP exhibited modest gut microbiome differences. Greater microbial richness paralleled prolapse severity but was largely attributable to age. In contrast, stage-associated enrichment of Clostridia vadinBB60 group, Eubacteriales, and Rhodospirillales persisted after age adjustment, suggesting taxonomic shifts specific to prolapse rather than aging alone. Elevated histologic inflammation and plasma LBP suggest a systemic inflammatory response consistent with an inflamm-aging framework. Together, these findings support a possible gut–pelvic floor axis and may provide groundwork for microbiome- and inflammation-targeted therapies.

RATIONALE:IPF is an irreversible and progressive type of lung fibrosis that is pathologically characterized as spatially heterogeneous. Despite the identified dominant risk factor for IPF as the gain-of-function MUC5B promoter variant, little is understood for how MUC5B drives lung fibrosis. OBJECTIVES:We used spatial transcriptomics from idiopathic pulmonary fibrosis (IPF) and unaffected control lung tissue to further understand the pathogenesis of MUC5B-driven lung fibrosis. METHODS:We captured 43 fields of view in 15 IPF and 13 controls with and without the MUC5B promoter variant using the CosMx® platform and identified 19 cell types via semi-supervised clustering. MEASUREMENTS AND MAIN RESULTS:MUC5B was ectopically expressed in AT2 cells in controls with the risk variant. We observed a decreased proportion of AT2 cells in controls and an increased proportion of aberrant basaloid cells in IPF associated with the MUC5B risk variant. We identified co-localized expression of MUC5B in respiratory bronchioles with 13 genes including the endoplasmic reticulum (ER) stress marker XBP1 and distal secretory markers SCGB3A1 and SCGB1A1. Experimentally, we demonstrated a direct relationship between MUC5B expression and ER stress in bronchiolar epithelia in vitro and validated the co-expression of MUC5B and XBP1 in the IPF lung. CONCLUSIONS:Based on our results, we conclude that MUC5B injures alveolar and bronchiolar epithelia that results in loss of AT2 cells and an increase in aberrant basaloid cells which initiates ER stress and a secretory phenotype in the terminal respiratory bronchiole, establishing a persistently injured distal airspace.

Rationale: Idiopathic pulmonary fibrosis (IPF) involves the progressive activation of fibroblasts, resulting in excessive deposition of a fibrillar collagen-rich extracellular matrix (ECM). Aberrant airway epithelial-like cells, some expressing mesenchymal markers, populate the alveolar compartment and contribute to tissue remodeling. Identifying endogenous protective factors counteracting these mechanisms may help develop novel treatment strategies. The collagen chaperone prolyl-3-hydroxylase 1 (P3H1) was previously found to be upregulated in end-stage interstitial lung disease including IPF. We hypothesized that P3H1 is consistently upregulated in IPF and that inhibiting P3H1 expression in primary lung cells alters collagen post-translational modifications (PTMs) and the overall ECM profile. Objectives: 1. To quantify P3H1 protein levels in independent IPF cohorts and define its cellular localization. 2. To assess alterations in collagen PTMs and ECM profiles in the absence of P3H1. 3. To explore the underlying molecular mechanisms. Methods: P3H1 expression was assessed by tandem mass spectrometry-based quantification and immunoblot analysis in two independent IPF cohorts. Localization of P3H1 in IPF tissue was analyzed by immunofluorescent stainings. P3H1 was knocked down in primary human lung fibroblasts (phLFs) and bronchial epithelial cells (phBECs) using siRNA, followed by gene expression analysis through bulk RNA sequencing and subsequent pathway enrichment analysis, LC-MS/MS proteomics for ECM and PTM analysis, Sircol assay, immunoblotting, and proliferation analysis by BrdU incorporation. Results: P3H1 protein was consistently increased in IPF lungs and localized to areas of bronchiolization and fibroblast foci. P3H1 knockdown in phLF upregulated TGF-β2, fibrillar collagens, fibronectin, and other fibrotic ECM components. Site-specific collagen PTM analysis demonstrated increased prolyl-4-hydroxylation of type I collagen in phLFs. A direct comparison of ECM changes under both conditions revealed that P3H1 knockdown partly phenocopied TGF-β effects. In phBECs, P3H1 knockdown reduced proliferation and induced the loss of basement membrane ECM components like laminins and type IV/XVII collagens. Concurrently, we observed increased expression of numerous mesenchymal markers and integrin β3, increased expression and secretion of type I collagen, and increased expression and release of TGF-β2 as the only altered TGF-β isoform. Pathway enrichment analysis underscored altered ECM organization, with TGF-β as the top predicted key regulator. Conclusion: P3H1 deficiency in primary lung cells induces expression and secretion of TGF-β2 and numerous other events typically associated with increased TGF-β signaling, epithelial injury, and fibrogenesis. Hence, overexpression of P3H1 in IPF serves an unexpected protective role in lung repair and the control of ECM quality that goes far beyond its function in collagen biosynthesis.

Adoptive cell transfers (ACTs) constitute an emerging platform for improving the systemic delivery of nano- and microparticle systems. Macrophages (Mφ) are an attractive cell type for particle-carrying ACTs because their attachment, phagocytosis, and chemotaxis can improve pharmacokinetics and reduce off-target effects. However, little is known about how macrophage transport and function change when carrying particles of different shapes, or whether these changes can be leveraged for improving ACTs. This work investigates macrophage interactions with biodegradable spherical and discoidal particles to promote or suppress phagocytosis, respectively. Adoptively transferred macrophages with internalized spheres (Mφ-S) or surface-bound discs (Mφ-D) possess enhanced targeted delivery to solid tumors compared to conventional free microparticle administration by 5.2-fold and exhibit distinct phenotypic profiles within the cold B16-F10 tumor microenvironment. Moreover, phenotypic changes are evaluated upon particle association by profiling the transcriptional, chromatin accessibility, and protein state. Mφ-S complexes adopt epigenetic changes and key biomarkers associated with a proinflammatory phenotype. In Mφ-D complexes, a diverse chromatin and protein landscape with simultaneous upregulation of both pro- and anti-inflammatory biomarkers is observed, suggesting functional flexibility is observed. These findings suggest particle shape can be used as a design parameter to influence the function of adoptive macrophage transfers without compromising their delivery performance.

Rationale: To identify cell specific molecular changes associated with sarcoidosis risk and progression, we aimed to characterize the cellular composition, gene expression patterns, and cell-cell interactions in BAL cells from patients with sarcoidosis (both progressive and non-progressive) and healthy controls. Methods: Single cell RNA-seq data were collected on 12 sarcoidosis and 4 control participants. We combined scRNA-seq data from these participants with our previously collected data on 4 sarcoidosis and 10 control participants for a final sample size of 16 sarcoidosis cases (8 progressive and 8 non-progressive) and 14 controls. Following initial preprocessing in CellRanger, data were quality controlled, combined, and clustered in Seurat. We tested differences in cell proportions by disease group using F-tests on cell proportions and differences in gene expression using pseudobulk analysis. Cell to cell communication and pathway analysis were performed using CellChat. Results: We identified five macrophage populations: resident, high metallothionein (MT) resident, recruited, profibrotic recruited, and proliferating macrophages. Each subpopulation displayed unique gene expression profiles, with notable differential expression of genes and pathways linked to sarcoidosis in resident macrophages, recruited macrophages, and proliferating macrophages. We also observed changes in gene expression associated with disease progression in resident and recruited macrophages. In non-macrophages cells, we observed a significant reduction in the number of B cells in sarcoidosis patients compared to controls. Among T cell populations, we identified specific transcriptional alterations at gene and pathway level. Additionally, we observed distinct differences in cell-to-cell interactions of macrophages and T cells between sarcoidosis patients and healthy controls. Conclusions: These findings underscore the complexity of immune cell involvement in sarcoidosis and highlight potential cellular and molecular targets for further investigation.

Rationale: Idiopathic pulmonary fibrosis (IPF) is a complex and heterogeneous disease. Given this, we reasoned that differences in genetic profiles may be associated with unique clinical and radiologic features. Computational image analysis, sometimes referred to as radiomics, provides objective, quantitative assessments of radiologic features in subjects with pulmonary fibrosis. Objectives: To determine if the genetic risk profile of patients with IPF identifies unique computational imaging phenotypes. Methods: Participants with IPF were included in this study if they had genotype data and computed tomography (CT) scans of the chest available for computational image analysis. The extent of lung fibrosis and the likelihood of a usual interstitial pneumonia (UIP) pattern were scored automatically using two separate, previously validated deep learning techniques for CT analysis. UIP pattern was also classified visually by radiologists according to established criteria. Results: Among 329 participants with IPF, MUC5B and ZKSCAN1 were independently associated with the deep learning-based UIP score. None of the common variants were associated with fibrosis extent by computational imaging. We did not find an association between MUC5B or ZKSCAN1 and visually assessed UIP pattern. Conclusions: Select genetic variants are associated with computer-based classification of UIP on CT in this IPF cohort. Analysis of radiologic features using deep learning may enhance our ability to identify important genotype-phenotype associations in fibrotic lung diseases.

The gain-of-function MUC5B promoter variant is the dominant risk factor for the development of idiopathic pulmonary fibrosis (IPF). However, its impact on protein expression in both nonfibrotic control and IPF lung specimens has not been well characterized. Utilizing laser capture microdissection coupled to mass spectrometry, we investigated the proteomic profiles of airway and alveolar epithelium in nonfibrotic controls (n = 12) and IPF specimens (n = 12), stratified by the MUC5B promoter variant. Through qualitative and quantitative analyses, as well as pathway analysis and immunohistological validation, we have identified a distinct MUC5B-associated protein profile. Notably, the nonfibrotic control alveoli exhibited substantial MUC5B-associated protein changes, with an increase in IL-3 signaling. Additionally, we found that epithelial cells overlying IPF fibroblastic foci clustered closely to alveolar epithelia and expressed proteins associated with cellular stress pathways. In conclusion, our findings suggest that the MUC5B promoter variant leads to protein changes in alveolar and airway epithelium that appear to be associated with initiation and progression of lung fibrosis.

Introduction: Sarcoidosis and tuberculosis (TB) patients abnormally respond to Mycobacterium tuberculosis (M.tb) antigens to form granulomas. Based on a transcriptomic analysis, we sought to determine if molecular pathways associated with granuloma formation in response to M.tb antigens fundamentally differ in sarcoidosis and latent TB infection (LTBI). Methods: PBMCs were obtained from TB naïve sarcoidosis (n = 6) and LTBI patients (n = 4), who had negative and positive interferon gamma release assays, respectively. PBMCs were immediately treated with polystyrene beads covalently coated with purified protein derivative (PPD) of M.tb, and cultured in RPMI medium for 7 days, at which time granuloma-like structures typically form. AmpliSeq Human Gene Expression kit was used to assess differential expression (DE) of genes from RNA derived from the granulomas. DE genes were identified, and the imputed biological implications of the DE genes were then assessed using pathway and upstream regulator modules in Ingenuity Pathway Analysis® and network analysis using protein-protein interactome data in NetworkAnalyst. Results: Despite the formation of histologically similar appearing granulomas 7 days after exposure to PPD-coated beads, we observed large differences in gene expression (5,103 DE genes based on false discovery rate-adjusted p < 0.05 and > 2-fold change) in granulomas derived from sarcoidosis compared to LTBI PMBCs. Ingenuity Pathway Analysis® identified multiple pro-inflammatory pathways (e.g., neutrophil degranulation, phagosome, S100, Toll-like receptor related) engaged during sarcoidosis granuloma formation, whereas senescence blocking pathways (DNA and histone methylation, DNA/telomere repair) were suppressed. Sarcoidosis granulomas also exhibit enhanced iron uptake pathways (e.g., CD163 mediated) and enhanced activation of MMPs, predicted to promote tissue remodeling. Upstream regulator and network analyses provided additional context for biological interpretation of differences in transcriptional profiles of granulomas derived from sarcoidosis compared to latent LTBI PMBCs. Figure 1 demonstrates top enriched canonical pathways with FDR-adjusted p < 0.05 and Z-scores > 3.5 (reflecting activation) or < -3.5 (reflecting inhibition). Conclusions: In response to identical M.tb antigen challenge, the genomic profiles of sarcoidosis and LTBI granulomas are dramatically different, emphasizing the unique characteristics of sarcoidosis immune response. These differences, with additional consideration of epigenetic and senescence mechanisms, may partially explain the typical adult onset of sarcoidosis and the potentially novel role played by the neutrophil degranulation pathway. The full implications in terms of TB infection susceptibility, tissue remodeling and other disease manifestations remain to be determined.

Most genetic variants identified through genome-wide association studies (GWASs) are suspected to be regulatory in nature, but only a small fraction colocalize with expression quantitative trait loci (eQTLs, variants associated with expression of a gene). Therefore, it is hypothesized but largely untested that integration of disease GWAS with context-specific eQTLs will reveal the underlying genes driving disease associations. We used colocalization and transcriptomic analyses to identify shared genetic variants and likely causal genes associated with critically ill COVID-19 and idiopathic pulmonary fibrosis. We first identified five genome-wide significant variants associated with both diseases. Four of the variants did not demonstrate clear colocalization between GWAS and healthy lung eQTL signals. Instead, two of the four variants colocalized only in cell type- and disease-specific eQTL datasets. These analyses pointed to higher ATP11A expression from the C allele of rs12585036, in monocytes and in lung tissue from primarily smokers, which increased risk of idiopathic pulmonary fibrosis (IPF) and decreased risk of critically ill COVID-19. We also found lower DPP9 expression (and higher methylation at a specific CpG) from the G allele of rs12610495, acting in fibroblasts and in IPF lungs, and increased risk of IPF and critically ill COVID-19. We further found differential expression of the identified causal genes in diseased lungs when compared to non-diseased lungs, specifically in epithelial and immune cell types. These findings highlight the power of integrating GWASs, context-specific eQTLs, and transcriptomics of diseased tissue to harness human genetic variation to identify causal genes and where they function during multiple diseases.

Introduction- Prior studies have observed elevated reactive oxygen species (ROS) and heme oxygenase-1 (HO-1) levels, reflecting oxidant stress, in the tissues of sarcoidosis patients. However, the role of ROS and HO-1/Signal Transducer and Activator of Transcription 3 (STAT3) signaling as potential drivers of granuloma formation, if any, remains unknown. Methods- PBMCs were obtained from TB naïve pulmonary sarcoidosis patients (n=5); based on negative interferon gamma assays. The PBMCs were immediately treated with polystyrene beads covalently coated with purified protein derivative of M.tb (PPD) or uncoated beads at a ratio of 50 beads per monocyte/macrophage, and cultured in RPMI medium for 7 days, at which time granuloma-like structures typically form only in response to PPD-coated beads. The magnitude of the granulomatous responses was quantified based on computational MIPAR image analysis following pretreatment with a flavonoid antioxidant (quercetin), cell permeable superoxide dismutase mimetic (TEMPOL), HO-1 inhibitor (OB 24) or STAT3 inhibitor (Stattic), compared to prednisone. Gene expression analysis was performed on RNA extracted from the PBMCs using AmpliSeq and differentially expressed genes were analyzed with Ingenuity Pathway Analysis®. Results- Pretreatments with antioxidants (quercetin, TEMPOL), HO-1 inhibitor (OB 24) or STAT3 inhibitor (Stattic) significantly reduced the granulomatous response, as reflected by reduce granuloma area fraction (see Figure). The dose-dependent inhibition of granuloma formation was comparable to that of prednisone, which is considered the first line treatment for sarcoidosis in the clinical setting. Differential gene expression pathway analysis (based on >2-fold expression; p<0.05) identified the cGAS-STING pathway, reflecting mitochondrial DNA oxidative stress. Conclusion- These experiments are the first, to our knowledge, to directly link oxidative stress and related HO-1/STAT3 signaling to sarcoidosis granuloma formation. These findings are consistent with prior clinical studies indicating that quercetin treatment is associated with reduced systemic markers of oxidative stress and inflammation (PMID: 21324570) and elevation of HO-1 levels in the lungs of pulmonary sarcoidosis patients (PMID: 19453654). The mechanisms promoting oxidant stress and the clinical implications of antioxidants remain to be determined but mitochondrial oxidative stress is implicated by gene expression analysis.

Idiopathic pulmonary fibrosis (IPF) is etiologically complex, with well-documented genetic and nongenetic origins. In this Review, we speculate that the development of IPF requires two hits: the first establishes a vulnerable bronchoalveolar epithelium, and the second triggers mechanisms that reprogram distal epithelia to initiate and perpetuate a profibrotic phenotype. While vulnerability of the bronchoalveolar epithelia is most often driven by common or rare genetic variants, subsequent injury of the bronchoalveolar epithelia results in persistent changes in cell biology that disrupt tissue homeostasis and activate fibroblasts. The dynamic biology of IPF can best be contextualized etiologically and temporally, including stages of vulnerability, early disease, and persistent and progressive lung fibrosis. These dimensions of IPF highlight critical mechanisms that adversely disrupt epithelial function, activate fibroblasts, and lead to lung remodeling. Together with better recognition of early disease, this conceptual approach should lead to the development of novel therapeutics directed at the etiologic and temporal drivers of lung fibrosis that will ultimately transform the care of patients with IPF from palliative to curative.

Gestation is a vulnerable window when exposure to per- and polyfluoroalkyl substances (PFAS) may impact child development and health. Epigenetic modification, including DNA methylation (DNAm), may be one mechanism linking prenatal PFAS exposure to offspring outcomes. We tested associations between prenatal PFAS and newborn DNAm in 1017 participants from 6 cohorts in the US Environmental influences on Child Health Outcomes consortium. Concentrations of PFAS [perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexanesulfonic acid (PFHxS), perfluorononanoic acid (PFNA), and perfluorodecanoic acid] were measured in maternal serum or plasma. DNAm was quantified in newborn dried blood spot or umbilical cord blood leukocytes using the Infinium HumanMethylation450 (450K) or MethylationEPIC (EPIC) arrays. We tested associations between prenatal PFAS and neonatal blood DNAm on the 450K (n = 772) and EPIC (n = 245) arrays; results were meta-analysed across the platforms. Regional changes in DNAm were investigated, and findings were checked for replication in the Michigan Mother-Infant Pairs (MMIP) cohort (n = 140). Following correction for false discovery rate (q = 0.1 for meta-analyses), we identified an association between PFHxS and one cytosine-guanine (CpG) mapped to CASC3 (q = 0.065) that replicated in MMIP (P = .006). PFOS was associated with six CpG sites, of which five were mapped to the genes KIAA1841, ABR, LEP, SERPINA1, and LOXL1. One differentially methylated region (DMR) was associated with prenatal PFOA exposure, and one DMR was associated with PFOS exposure. In this multicohort analysis including a diverse group from the USA, PFOA, PFOS, PFHxS, and PFNA exposures in pregnancy were associated with offspring DNAm, and the implications for children's health merit further exploration.

Rationale: Pulmonary sarcoidosis is a clinically heterogenous disease with variable presentations and disease course. Defining progressive pulmonary disease remains a challenge. Immune dysfunction appears to be critical to sarcoidosis pathogenesis and studies suggest that microRNAs (miRNAs) are important regulators of gene expression. In this study, we investigated if progressive disease was associated with lung function changes, and if changes in lung function were associated with miRNA expression. Methods: Bronchoalveolar lavage (BAL) cells were collected from individuals with biopsy-proven sarcoidosis(n=57). FEV1, FVC, and DLCO were collected at the time of BAL. Phenotypes were determined as follows: progressive(P) cases were defined as having a 10% or greater decline in FEV1 or FVC, or 15% or greater decline in DLCO, and/or worsening chest imaging after BAL. If the above criteria were not met, then cases were deemed non-progressive(NP). Changes in FEV1, FVC, DLCO over time in individuals with NP and P disease were evaluated. Mixed models were constructed with lung function measures as outcomes to determine if miRNAs differentially expressed between sarcoidosis cases and controls (determined from a previous study, Konigsberg et al. Respiratory Research, 2024), and their interaction terms with duration, were associated with changes in lung function. These miRNAs included mir-184, mir-1976, mir-199a-3p/199b-3p, mir-199b-5p, mir-143-3p, mir-582-3p, mir-582-5p. All models were adjusted for age, sex, smoking status, height, and weight. Results: There were 36 NP and 21 P cases. Females were 29% of P cases and 72% of NP cases. 12 P cases were on treatment. Overall FEV1, FVC, and DLCO decreased with time in individuals with P sarcoidosis, while these lungs parameters were stable or increased in the individuals with NP sarcoidosis. Though changes in the expression levels of miRNAs were not associated with changes in lung function over time, a one unit increase in the expression of miR-1976 was associated with an 18.60% (95% CI = (2.49%, 32.05%), p= 0.03) decrease in DLCO on average, after adjusting for other covariates (Table1). Conclusions: Individuals with P sarcoidosis demonstrate decline in lung function over time, even though some were on treatment for their disease, suggesting that lung function is an important marker of progressive pulmonary disease. However, miRNA expression in the BAL was not associated with changes in lung parameters over time, which could be due to small samples sizes in this study or potential differences in tissue specific miRNA expression. An increase in miR-1976 was associated with a decrease in DLCO.

BackgroundType 1 diabetes (T1D) is preceded by a heterogenous pre-clinical phase, islet autoimmunity (IA). We aimed to identify pre vs. post-IA seroconversion (SV) changes in DNAm that differed across three IA progression phenotypes, those who lose autoantibodies (reverters), progress to clinical T1D (progressors), or maintain autoantibody levels (maintainers).MethodsThis epigenome-wide association study (EWAS) included longitudinal DNAm measurements in blood (Illumina 450K and EPIC) from participants in Diabetes Autoimmunity Study in the Young (DAISY) who developed IA, one or more islet autoantibodies on at least two consecutive visits. We compared reverters - individuals who sero-reverted, negative for all autoantibodies on at least two consecutive visits and did not develop T1D (n=41); maintainers - continued to test positive for autoantibodies but did not develop T1D (n=60); progressors - developed clinical T1D (n=42). DNAm data were measured before (pre-SV visit) and after IA (post-SV visit). Linear mixed models were used to test for differences in pre- vs post-SV changes in DNAm across the three groups. Linear mixed models were also used to test for group differences in average DNAm. Cell proportions, age, and sex were adjusted for in all models. Median follow-up across all participants was 15.5 yrs. (interquartile range (IQR): 10.8-18.7).ResultsThe median age at the pre-SV visit was 2.2 yrs. (IQR: 0.8-5.3) in progressors, compared to 6.0 yrs. (IQR: 1.3-8.4) in reverters, and 5.7 yrs. (IQR: 1.4-9.7) in maintainers. Median time between the visits was similar in reverters 1.4 yrs. (IQR: 1-1.9), maintainers 1.3 yrs. (IQR: 1.0-2.0), and progressors 1.8 yrs. (IQR: 1.0-2.0). Changes in DNAm, pre- vs post-SV, differed across the groups at one site (cg16066195) and 11 regions. Average DNAm (mean of pre- and post-SV) differed across 22 regions.ConclusionDifferentially changing DNAm regions were located in genomic areas related to beta cell function, immune cell differentiation, and immune cell function.

Objective: Fetal exposures may impact offspring epigenetic signatures and adiposity. The authors hypothesized that maternal metabolic traits associate with cord blood DNA methylation, which, in turn, associates with child adiposity.Methods: Fasting serum was obtained in 588 pregnant women (27-34 weeks' gestation), and insulin, glucose, high-density lipoprotein cholesterol, triglycerides, and free fatty acids were measured. Cord blood DNA methylation and child adiposity were measured at birth, 4-6 months, and 4-6 years. The association of maternal metabolic traits with DNA methylation (429,246 CpGs) for differentially methylated probes (DMPs) and regions (DMRs) was tested. The association of the first principal component of each DMR with child adiposity was tested, and mediation analysis was performed.Results: Maternal triglycerides were associated with the most DMPs and DMRs of all traits tested (261 and 198, respectively, false discovery rate < 0.05). DMRs were near genes involved in immune function and lipid metabolism. Triglyceride-associated CpGs were associated with child adiposity at 4-6 months (32 CpGs) and 4-6 years (2 CpGs). One, near CD226, was observed at both timepoints, mediating 10% and 22% of the relationship between maternal triglycerides and child adiposity at 4-6 months and 4-6 years, respectively.Conclusions: DNA methylation may play a role in the association of maternal triglycerides and child adiposity.