Abstract Background Blood-based DNA methylation has been linked to obesity and metabolic health, yet its relationship to adipose tissue function remains incompletely understood. This study aimed to investigate the epigenetic regulation of EIF5A (Eukaryotic translation initiation factor 5A-1) and TGIF1 (TGFB Induced Factor Homeobox 1) across blood and adipose tissue in obesity. Methods Candidate genes were identified using a multi-step gene selection approach integrating transcriptomic and epigenomic data from blood and adipose tissue samples obtained from children and adults across four diverse population- and disease-focused cohorts. Genes were prioritized based on differential DNA methylation and gene expression in obesity. Targeted bisulfite sequencing of EIF5A and TGIF1 was conducted in blood samples from adults across BMI-defined groups and from children prior to the development of obesity, to validate candidate loci and to examine associations with metabolic and adipocyte-related phenotypes. Results In adults from the Leipzig Obesity BioBank, blood DNA methylation (N = 150) of both EIF5A and TGIF1 was significantly increased in individuals with obesity. EIF5A mRNA expression (N = 1554) was significantly higher in omental-visceral adipose tissue compared with subcutaneous adipose tissue. Blood DNA methylation of EIF5A was associated with body mass index (BMI), glycated hemoglobin (HbA1c), and leukocyte counts, particularly among individuals with type 2 diabetes mellitus. In children, blood DNA methylation (N = 75) of EIF5A was associated with longitudinal HbA1c trajectories. For TGIF1, DNA methylation levels were increased in subcutaneous adipose tissue (N = 219) of children with obesity and correlated with fasting serum insulin concentrations. Across cohorts, TGIF1 regulation in both blood and adipose tissue showed consistent associations with adipocyte size. Notably, blood DNA methylation of TGIF1 in childhood was associated with body fat mass and HbA1c at later follow-up despite normal weight at baseline. Conclusion EIF5A and TGIF1 DNA methylation represent cross-tissue epigenetic signatures linking blood-based DNA methylation to adipose tissue dysfunction, adipocyte hypertrophy, and early metabolic risk. These findings support the potential of blood DNA methylation markers to reflect adipose tissue health and metabolic outcomes across the lifespan.

Abstract Objective Maternal hormonal status can have long-term effects on offspring metabolic health and is likely regulated via epigenetic mechanisms. We elucidated the effects of maternal thyroid hormones on the epigenetic regulation of leptin (Lep) transcription in adipose tissue (AT) and subsequently investigated the role of DNA methylation at a Lep upstream enhancer (UE) in adipocyte biology. Results Pregnant mice treated with triiodothyronine (T3) produced offspring with reduced body weight, total fat mass, and gonadal white adipose tissue (gWAT) mass at 6 months of age (treatment: N = 8; control: N = 12). Compared with control offspring, exclusively female offspring of T3-treated mothers presented lower Lep mRNA levels and higher Lep UE methylation in gWAT. In murine preadipocytes, targeted demethylation of the Lep UE via a dCas9-SunTag-TET1 system reduced methylation by ~ 20%, but this effect was insufficient to alter Lep expression or lipid accumulation after differentiation. In human omental visceral AT (OVAT) samples from the Leipzig Obesity BioBank (LOBB, N = 52), LEP UE methylation was associated with body fat percentage, and mediation analysis indicated that leptin serum levels partially mediate this association exclusively in females. Conclusion Findings from the animal model suggest that maternal thyroid hormones influence offspring gWAT Lep expression in a sex-specific manner, potentially through changes in Lep UE methylation. However, in vitro experiments indicate that Lep UE methylation alone is not sufficient to regulate Lep expression or adipocyte lipid accumulation. In humans with obesity, LEP UE methylation is associated with body fat percentage, with leptin serum levels potentially acting as a mediator exclusively in females.

BACKGROUND AND AIMS:Genetic and epigenetic variations in the Sarcospan (SSPN) gene are associated with parameters of fat distribution (body mass index, waist-to-hip ratio), glucose homeostasis and adipocyte size in human potentially by affecting adipogenesis. This study aims at clarifying the impact of SSPN on adipogenesis, particularly focusing on its promoter methylation. MATERIALS AND METHODS:Immortalized murine epididymal preadipocytes were transfected with fluorescence-marked plasmids coding for DNMT3a, CRISPR/dCas9-Suntag and vectors carrying guide RNAs complementary to the transcription start site region and differentiated to mature adipocytes. We performed siRNA-mediated Sspn knockdown in epididymal preadipocytes, measured target DNA methylation using pyrosequencing and quantified transcriptional changes of Sspn and adipogenic genes by qPCR. Additionally, we correlated SSPN mRNA values and clinical characteristics from a large human adipose tissue biobank (Leipzig Obesity Biobank). RESULTS:Epigenetic editing of the Sspn regulatory region in preadipocytes resulted in a significant increase (up to 35 %) in DNA promoter methylation throughout adipocyte differentiation but showed only minor effects on Sspn expression and fat storage. Though siRNA knockdown could also not contribute to understand the role of Sspn in a 2D adipogenesis model, large-scale correlation analyses still indicate the gene to be a key player in fat distribution and glucose homeostasis. CONCLUSIONS:Although the epigenetic downregulation of Sspn showed only marginal effects on adipogenesis, associations of SSPN expression in human adipose tissue with parameters of fat distribution and glucose homeostasis make it a promising candidate for further studies addressing metabolic processes in adipose tissue.

Obesity, lifestyle factors, and malnutrition increase the risk of cardiovascular events and mortality, however the interplay between lifestyle and malnutrition remains underexplored. We hypothesize that a healthier lifestyle score (lower LS)—reflecting favorable diet, higher physical activity, non-smoking, and low alcohol intake—is associated with lower cardiovascular risk (Framingham Risk Score, FRS) and reduced mortality in the LIFE-Adult-Study, and together may sharpen risk detection and prevention. We assessed the LS in 6073 participants of the LIFE-Adult-Study and analyzed associations with cardiometabolic biomarkers and FRS using multivariable linear regression (ANCOVA with post-hoc tests). All-cause mortality and malnutrition (CONUT, PNI, NRI) were analyzed across Lifestyle Score terciles using Cox models. LS categorization revealed 2038 individuals with low, 2140 with moderate, and 1895 with high lifestyle scores. Across LS terciles (higher LS = less healthy), BMI and triglycerides increased, while HDL decreased (ANCOVA; BMI adjusted for age and sex; lipids additionally for BMI; all p < 0.001). Malnutrition decreased with an increasing lifestyle score, while the FRS increased from 6.3 (LS ≤ 21) to 9.0% (LS > 32; p < 1 × 10⁻⁷). Participants with the unhealthiest LS had higher mortality, predominantly driven by smoking. The LS categorizes health status via metabolic parameters and identifies links to cardiovascular risk and malnutrition in the LIFE-Adult cohort, highlighting the value of integrating lifestyle factors into clinical diagnostics.

Background Studies on DNA methylation following bariatric surgery have primarily focused on blood cells, while it is unclear to which extend it may re fl ect DNA methylation pro fi les in speci fi c metabolically relevant organs such as adipose tissue. Here, we investigated whether adipose tissue depots speci fi c methylation changes after bariatric surgery are mirrored in blood. Methods Using Illumina 850K EPIC technology, we analysed genome-wide DNA methylation in paired blood, subcutaneous and omental visceral AT (SAT/OVAT) samples from nine individuals (N = 6 female) with severe obesity pre- and post-surgery. Findings The numbers and effect sizes of differentially methylated regions (DMRs) post-bariatric surgery were more pronounced in AT (SAT: 12,865 DMRs from - 11.5 to 10.8%; OVAT: 14,632 DMRs from - 13.7 to 12.8%) than in blood (9267 DMRs from - 8.8 to 7.7%). Cross-tissue DMRs implicated immune-related genes. Among them, 49 regions could be validated with similar methylation changes in blood from independent individuals. Fourteen DMRs correlated with differentially expressed genes in AT post bariatric surgery, including downregulation of PIK3AP1 in both SAT and OVAT. DNA methylation age acceleration was signi fi cantly higher in AT compared to blood, but remained unaffected after surgery.

Background: Thyroid hormones affect fetal energy metabolism, particularly by regulating oxygen consumption and glucose disposal. Previous studies in rats have shown that maternal hypothyroidism during pregnancy increases visceral fat mass and causes glucose intolerance in the offspring. To date, little is known about the transgenerational effects of maternal hypothyroidism on intrauterine programming of adiposity and the implications for energy homeostasis and metabolic health.

Background The placenta, which has a low permeability for thyroid hormones (TH), is considered to be the interface between mother and fetus. The inhibition of maternal TH production leads to severe hypothyroidism in the offspring, since the fetal thyroid gland cannot produce TH hormones on its own until 20 weeks of gestation. Several studies have reported the strong link between thyroid dysfunctions, obesity and metabolic disorders like diabetes mellitus. Furthermore, a number of epigenetic markers have been identified that regulate glucose tolerance and insulin sensitivity.

A large body of research demonstrates that the maternal thyroid function during pregnancy is critical for the metabolic health of the child. This project investigates the molecular mechanisms by which a dysfunction of maternal thyroid hormone production during pregnancy affects adipose tissue differentiation and function in the offspring.

Over the past 50 years, the number of overweight/obese people increased significantly, making obesity a global public health challenge. Apart from rare monogenic forms, obesity is a multifactorial disease, most likely resulting from a concerted interaction of genetic, epigenetic and environmental factors. Although recent studies opened new avenues in elucidating the complex genetics behind obesity, the biological mechanisms contributing to individual's risk to become obese are not yet fully understood. Non-genetic factors such as eating behaviour or physical activity are strong contributing factors for the onset of obesity. These factors may interact with genetic predispositions most likely via epigenetic mechanisms. Epigenome-wide association studies or methylome-wide association studies are measuring DNA methylation at single CpGs across thousands of genes and capture associations to obesity phenotypes such as BMI. However, they only represent a snapshot in the complex biological network and cannot distinguish between causes and consequences. Intervention studies are therefore a suitable method to control for confounding factors and to avoid possible sources of bias. In particular, intervention studies documenting changes in obesity-associated epigenetic markers during lifestyle driven weight loss, make an important contribution to a better understanding of epigenetic reprogramming in obesity. To investigate the impact of lifestyle in obesity state specific DNA methylation, especially concerning the development of new strategies for prevention and individual therapy, we reviewed 19 most recent human intervention studies. In summary, this review highlights the huge potential of targeted interventions to alter disease-associated epigenetic patterns. However, there is an urgent need for further robust and larger studies to identify the specific DNA methylation biomarkers which influence obesity.

Background: The capacity of a polyphenol-enriched diet to modulate the epigenome in vivo is partly unknown. Given the beneficial metabolic effects of a Mediterranean (MED) diet enriched in polyphenols and reduced in red/processed meat (green-MED), as previously been proven by the 18-month DIRECT PLUS randomized controlled trial, we analyzed the effects of the green-MED diet on methylome and transcriptome levels to highlight molecular mechanisms underlying the observed metabolic improvements.Methods: Our study included 260 participants (baseline BMI = 31.2 kg/m(2), age = 5 years) of the DIRECT PLUS trial, initially randomized to one of the intervention arms: A. healthy dietary guidelines (HDG), B. MED (440 mg polyphenols additionally provided by walnuts), C. green-MED (1240 mg polyphenols additionally provided by walnuts, green tea, and Mankai: green duckweed shake). Blood methylome and transcriptome of all study subjects were analyzed at baseline and after completing the 18-month intervention using Illumina EPIC and RNA sequencing technologies.Results: A total of 1573 differentially methylated regions (DMRs; false discovery rate (FDR) < 5 %) were found in the green-MED compared to the MED (177) and HDG (377) diet participants. This corresponded to 1753 differentially expressed genes (DEGs; FDR < 5 %) in the green-MED intervention compared to MED (7) and HDG (738). Consistently, the highest number (6 %) of epigenetic modulating genes was transcriptionally changed in subjects participating in the green-MED intervention. Weighted cluster network analysis relating transcriptional and phenotype changes among participants subjected to the green-MED intervention identified candidate genesassociated with serum-folic acid change (all P < 1 x 10(-3)) and highlighted one module including the KIR3DS1 locus, being negatively associated with the polyphenol changes (e.g. P < 1 x 10(-4)), but positively associated with the MRI-assessed superficial subcutaneous adipose area-, weight-and waist circumference-18-month change (all P < 0.05). Among others, this module included the DMR gene Cystathionine Beta-Synthase, playing a major role in homocysteine reduction.Conclusions: The green-MED high polyphenol diet, rich in green tea and Mankai, renders a high capacity to regulate an individual's epigenome. Our findings suggest epigenetic key drivers such as folate and green diet marker to mediate this capacity and indicate a direct effect of dietary polyphenols on the one-carbon metabolism.

Background To highlight molecular mechanisms underlying the beneficial metabolic effects of a Mediterranean (MED) diet enriched in polyphenols and reduced in red/processed meat (greenMED), we analyzed its effects on methylome and transcriptome in the 18-month DIRECT PLUS randomized controlled trial.

AbstractObjectiveObesity is driven by modifiable lifestyle factors whose effects may be mediated by epigenetics. Therefore, we investigated lifestyle effects on blood DNA methylation in participants of the LIFE‐Adult study, a well‐characterised population‐based cohort from Germany.Research design and methodsLifestyle scores (LS) based on diet, physical activity, smoking and alcohol intake were calculated in 4107 participants of the LIFE‐Adult study. Fifty subjects with an extremely healthy lifestyle and 50 with an extremely unhealthy lifestyle (5th and 95th percentiles LS) were selected for genome‐wide DNA methylation analysis in blood samples employing Illumina Infinium® Methylation EPIC BeadChip system technology.ResultsDifferences in DNA methylation patterns between body mass index groups (<25 vs. >30 kg/m2) were rather marginal compared to inter‐lifestyle differences (0 vs. 145 differentially methylated positions [DMPs]), which identified 4682 differentially methylated regions (DMRs; false discovery rate [FDR <5%) annotated to 4426 unique genes. A DMR annotated to the glutamine‐fructose‐6‐phosphate transaminase 2 (GFPT2) locus showed the strongest hypomethylation (∼6.9%), and one annotated to glutamate rich 1 (ERICH1) showed the strongest hypermethylation (∼5.4%) in healthy compared to unhealthy lifestyle individuals. Intersection analysis showed that diet, physical activity, smoking and alcohol intake equally contributed to the observed differences, which affected, among others, pathways related to glutamatergic synapses (adj. p < .01) and axon guidance (adj. p < .05). We showed that methylation age correlates with chronological age and waist‐to‐hip ratio with lower DNA methylation age (DNAmAge) acceleration distances in participants with healthy lifestyles. Finally, two identified top DMPs for the alanyl aminopeptidase (ANPEP) locus also showed the strongest expression quantitative trait methylation in blood.ConclusionsDNA methylation patterns help discriminate individuals with a healthy versus unhealthy lifestyle, which may mask subtle methylation differences derived from obesity.

Kidney stone disease (KSD) is a prevalent condition associated with high morbidity, frequent recurrence, and progression to chronic kidney disease (CKD). The etiology is multifactorial, depending on environmental and genetic factors. Although monogenic KSD is frequent in children, unbiased prevalence data of heritable forms in adults is scarce. Within 2 years of recruitment, all patients hospitalized for urological kidney stone intervention at our center were consecutively enrolled for targeted next generation sequencing (tNGS). Additionally, clinical and metabolic assessments were performed for genotype-phenotype analyses. The cohort comprised 155 (66%) males and 81 (34%) females, with a mean age at first stone of 47 years (4-86). The diagnostic yield of tNGS was 6.8% (16/236), with cystinuria (SLC3A1, SLC7A9), distal renal tubular acidosis (SLC4A1), and renal phosphate wasting (SLC34A1, SLC9A3R1) as underlying hereditary disorders. While metabolic syndrome traits were associated with late-onset KSD, hereditary KSD was associated with increased disease severity in terms of early-onset, frequent recurrence, mildly impaired kidney function, and common bilateral affection. By employing systematic genetic analysis to a less biased cohort of common adult kidney stone formers, we demonstrate its diagnostic value for establishing the underlying disorder in a distinct proportion. Factors determining pretest probability include age at first stone (<40 years), frequent recurrence, mild CKD, and bilateral KSD.

BACKGROUND AND AIMS:In the CENTRAL trial context, we found diverse liver fat dynamics in response to different dietary interventions. Epigenetic mechanisms may contribute to the intraindividual variation. Moreover, genetic factors are involved in developing nonalcoholic fatty-liver disease (NAFLD), a disease reflected by an increase in intrahepatic fat (IHF). In this exploratory analysis, we primarily aimed to examine the effect of lifestyle interventions on DNA-methylation of NAFLD related genes associated with IHF.METHODS:For 120 participants from the CENTRAL trial, an 18-month regimen of either low-fat (LF) or Mediterranean-low carbohydrate (MED/LC) diets, with or without physical activity (PA+/PA-), was instructed. Magnetic resonance imaging was used to measure IHF%, which was analysed for association with CpG specific DNA-methylation levels of 41 selected candidate genes. Single-nucleotide polymorphisms known to be associated with NAFLD within the studied genes were genotyped by TaqMan assays.RESULTS:At baseline, participants (92% men; body mass index = 30.2 kg/m2 ) had mean IHF of 10.7% (59% NAFLD). Baseline-IHF% was inversely correlated with DNA-methylation at individual CpGs within AC074286.1, CRACR2A, A2MP1, FARP1 (P < .05 for all multivariate models). FARP1 rs9584805 showed association with IHF, with the prevalence of NAFLD and baseline methylation level of the CpG site (cg00071727) associated with IHF%. Following 18-month lifestyle intervention, differential DNA-methylation patterns were observed between diets at cg14335324 annotated to A2MP1 (P = .04, LF vs. MED/LC), and differential DNA-methylation between PA groups within AC074286.1, CRACR2A, and FARP1 CpGs (P < .05 for all, PA-vs. PA+).CONCLUSIONS:This study suggests epigenetic markers for IHF and potential epigenetic remodeling after long-term lifestyle interventions.

We show that DNA methylation pattern have the potential to discriminate individuals living a healthy vs. unhealthy daily lifestyle whilst this has a strong effect on blood DNA methylation pattern and may mask subtle methylation differences related to obesity state itself.

Obesity is driven by modifiable lifestyle factors whose effects may be mediated by epigenetics. Therefore, we investigated lifestyle effects (diet, physical activity, smoking and alcohol) on blood DNA methylation in participants of the LIFE-Adult study, a well-characterized population-based cohort from Germany. Fifty subjects with an extremely healthy and 50 with an extremely unhealthy lifestyle were selected for genome-wide DNA methylation analysis in blood samples. Whereas obesity was only marginally related to variability in DNA methylation pattern, comparisons between lifestyle categories resulted in 145 Differentially Methylated Positions (DMPs) and 4682 Differentially Methylated Regions (DMRs) annotated to 4426 unique genes. Intersection analysis showed that diet, physical activity, smoking and alcohol intake are equally contributing to the observed differences, which particularly affects pathways related to glutamatergic synapse and axon guidance. DNA methylation patterns help discriminate individuals with a healthy vs. unhealthy lifestyle, which may mask subtle methylation differences derived from obesity.

In this study, we show that DNA methylation changes are associated with differential gene expression and the phenotypic improvements after bariatric surgery. Further studies are ongoing addressing long-term methylation changes of candidate sites after surgery, which helps to explore the role of DNA methylation on beneficial effects of bariatric surgery.

Subcutaneous (sc) and visceral (vis) adipose tissue (AT) contribute to the variability in pathophysiological consequences of obesity and adverse fat distribution. To gain insights into the molecular mechanisms distinguishing vis and sc fat, we compared the transcriptome during differentiation of immortalized adipocytes from murine epididymal (epi) and inguinal (ing) AT. RNA was extracted on different days of adipogenesis (-2, 0, 2, 4, 6, 8) and analyzed using Clariom™ D mouse assays (Affymetrix) covering >214,900 transcripts in >66,100 genes. Transcript Time Course Analysis revealed 137 differentially expressed genes. The top genes with most divergent expression dynamics included developmental genes like Alx1, Lhx8, Irx1/2, Hoxc10, Hoxa5/10, and Tbx5/15. According to pathway analysis the majority of the genes were enriched in pathways related to AT development. Finally, in paired samples of human vis and sc AT (N = 63), several of these genes exhibited depot-specific variability in expression which correlated closely with body mass index and/or waist-to-hip ratio. In conclusion, intrinsically programmed differences in gene expression patterns during adipogenesis suggest that fat depot specific regulation of adipogenesis contributes to individual risk of obesity.

Loss-of-function mutations of SLC34A3 represent an established cause of a distinct renal phosphate wasting disorder termed hereditary hypophosphatemic rickets with hypercalciuria (HHRH). SLC34A3 encodes the renal phosphate transporter NaPi2c expressed at the apical brush border of proximal renal tubules. Substitution of p.Ser192Leu is one of the most frequent genetic changes among HHRH patients in Europe, but has never been systematically evaluated, clinically or on a cellular level. Identification of a 32-year-old female with a homozgyous c.575C>T, p.Ser192Leu substitution enabled a more comprehensive assessment of the impact of this missense variant. Clinically, the patient showed renal phosphate wasting and nephrocalcinosis without any bone abnormalities. Heterozygous carriers of deleterious SLC34A3 variants were previously described to harbor an increased risk of kidney stone formation and renal calcification. We hence examined the frequency of p.Ser192Leu variants in our adult kidney stone cohort and compared the results to clinical findings of previously published cases of both mono- and biallelic p.Ser192Leu changes. On a cellular level, p.Ser192Leu-mutated transporters localize to the plasma membrane in different cellular systems, but lead to significantly reduced transport activity of inorganic phosphate upon overexpression in Xenopus oocytes. Despite the reduced function in ectopic cellular systems, the clinical consequences of p.Ser192Leu may appear relatively mild, at least in our index patient, and can potentially be missed in clinical practice.