Publications by authors named "Johannes Hertel"

Genetic studies of the metabolome can uncover enzymatic and transport processes shaping human metabolism. Using rare variant aggregation testing based on whole-exome sequencing data to detect genes associated with levels of 1,294 plasma and 1,396 urine metabolites, we discovered 235 gene-metabolite associations, many previously unreported. Complementary approaches (genetic, computational (in silico gene knockouts in whole-body models of human metabolism) and one experimental proof of principle) provided orthogonal evidence that studies of rare, damaging variants in the heterozygous state permit inferences concordant with those from inborn errors of metabolism.

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  • Antimicrobial autoantigenic glycoprotein 2 (GP2) plays a significant role in the immune system and is linked to the gut microbiome, but its systemic effects and associations are not fully understood.
  • In a study involving 2,812 participants, higher fecal GP2 levels were found in those with a higher body mass index and smokers, while lower levels were associated with healthier factors, such as good pancreatic function and diet.
  • Increased GP2 levels correlated with less gut microbial diversity, higher systemic inflammation, and a shift towards potentially harmful bacteria, suggesting that GP2 could serve as a biomarker for gut health and inflammation.
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Intense psychosocial stress during early life has a detrimental effect on health-disease balance in later life. Simultaneously, despite its sensitivity to stress, the developing microbiome contributes to long-term health. Following stress exposure, HPA-axis activation regulates the "fight or flight" response with the release of glucose and cortisol.

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  • * Our findings revealed lower levels of formate and fumarate in individuals with AD, along with decreased microbial secretion of formate in personalized metabolic models.
  • * The study highlights that specific genetic reactions linked to AD may affect formate production, suggesting its potential as an early marker and indicating a complex interplay between gut microbiota and AD.
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Understanding the effects of the microbiome on the host's metabolism is core to enlightening the role of the microbiome in health and disease. Herein, we develop the paradigm of in silico in vivo association pattern analyses, combining microbiome metabolome association studies with in silico constraint-based community modeling. Via theoretical dissection of confounding and causal paths, we show that in silico in vivo association pattern analyses allow for causal inference on microbiome-metabolome relations in observational data.

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Characterization of thermoelectric transport properties for temperature sensing, cooling, and energy harvesting applications is necessary for a reliable device performance in progressively minimized computer chips. In this contribution, we present a fully automated thermovoltage and sheet resistance measurement setup, which is calibrated and tested for the production of silicon- and silicon-germanium-doped as well as silicide complementary metal-oxide-semiconductor-compatible thin films. A LabVIEW-programmed software application automatically controls the measurement and recording of thermovoltages at individually defined temperature set points.

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  • * They utilized whole-genome sequencing to create personalized models that showed reduced formate production in individuals with AD, connecting this to specific genetic factors linked to the disease.
  • * The findings suggest that reduced formate could serve as an early marker for AD and reveal a complex relationship between gut microbiota and the disease, potentially leading to new diagnostic and treatment strategies.
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COVID-19, a systemic multi-organ disease resulting from infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is known to result in a wide array of disease outcomes, ranging from asymptomatic to fatal. Despite persistent progress, there is a continued need for more accurate determinants of disease outcomes, including post-acute symptoms after COVID-19. In this study, we characterised the serum metabolomic changes due to hospitalisation and COVID-19 disease progression by mapping the serum metabolomic trajectories of 71 newly hospitalised moderate and severe patients in their first week after hospitalisation.

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Metabolome reflects the interplay of genome and exposome at molecular level and thus can provide deep insights into the pathogenesis of a complex disease like major depression. To identify metabolites associated with depression we performed a metabolome-wide association analysis in 13,596 participants from five European population-based cohorts characterized for depression, and circulating metabolites using ultra high-performance liquid chromatography/tandem accurate mass spectrometry (UHPLC/MS/MS) based Metabolon platform. We tested 806 metabolites covering a wide range of biochemical processes including those involved in lipid, amino-acid, energy, carbohydrate, xenobiotic and vitamin metabolism for their association with depression.

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  • The study presents the first constraint-based modeling of a single individual's gut microbiome affected by gastrointestinal inflammation, using extensive biomarker and fecal sample data over 16 months.
  • It identifies overproduction of more than 24 metabolites linked to inflammation, revealing shifts in microbial species and metabolic pathways during different phases of the condition.
  • The research concludes that changes in the gut microbiome can significantly affect overall metabolism and organ function, suggesting future studies could explore how diet and treatment influence these microbial dynamics.
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Background: Metabolic Syndrome (MetS) is characterized by risk factors such as abdominal obesity, hypertriglyceridemia, low high-density lipoprotein cholesterol (HDL-C), hypertension, and hyperglycemia, which contribute to the development of cardiovascular disease and type 2 diabetes. Here, we aim to identify candidate metabolite biomarkers of MetS and its associated risk factors to better understand the complex interplay of underlying signaling pathways.

Methods: We quantified serum samples of the KORA F4 study participants (N = 2815) and analyzed 121 metabolites.

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  • The human microbiome significantly impacts how effective and safe certain drugs are for individuals, suggesting that personalized medicine should consider microbial effects.
  • The study introduces AGORA2, an updated computational resource that includes detailed data on 7,302 gut microorganism strains and their interactions with 98 different drugs, enhancing previous models.
  • AGORA2 shows high accuracy in predicting how gut microbes alter drugs, and it can tailor drug conversion predictions based on microbiome data from patients with colorectal cancer, highlighting the importance of individual factors like age and sex.
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Microbial metabolites measured using NMR may serve as markers for physiological or pathological host-microbe interactions and possibly mediate the beneficial effects of microbiome diversity. Yet, comprehensive analyses of gut microbiome data and the urine NMR metabolome from large general population cohorts are missing. Here, we report the associations between gut microbiota abundances or metrics of alpha diversity, quantified from stool samples using 16S rRNA gene sequencing, with targeted urine NMR metabolites measures from 951 participants of the Study of Health in Pomerania (SHIP).

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The early-life microbiome (ELM) interacts with the psychosocial environment, in particular during early-life adversity (ELA), defining life-long health trajectories. The ELM also plays a significant role in the maturation of the immune system. We hypothesised that, in this context, the resilience of the oral microbiomes, despite being composed of diverse and distinct communities, allows them to retain an imprint of the early environment.

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The human microbiome plays an important role in human health and disease. Meta-omics analyses provide indispensable data for linking changes in microbiome composition and function to disease etiology. Yet, the lack of a mechanistic understanding of, e.

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Depression constitutes a leading cause of disability worldwide. Despite extensive research on its interaction with psychobiological factors, associated pathways are far from being elucidated. Metabolomics, assessing the final products of complex biochemical reactions, has emerged as a valuable tool for exploring molecular pathways.

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Characterizing the metabolic functions of the gut microbiome in health and disease is pivotal for translating alterations in microbial composition into clinical insights. Two major analysis paradigms have been used to explore the metabolic functions of the microbiome but not systematically integrated with each other: statistical screening approaches, such as metabolome-microbiome association studies, and computational approaches, such as constraint-based metabolic modeling. To combine the strengths of the two analysis paradigms, we herein introduce a set of theoretical concepts allowing for the population statistical treatment of constraint-based microbial community models.

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Inflammatory bowel diseases, such as Crohn's Disease, are characterised by an altered blood and faecal metabolome, and changes in gut microbiome composition. Here, we present an efficient, scalable, tractable systems biology framework to mechanistically link microbial strains and faecal metabolites. We retrieve strain-level relative abundances from metagenomics data from a cohort of paediatric Crohn's Disease patients with and without dysbiosis and healthy control children and construct and interrogate a personalised microbiome model for each sample.

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  • The study investigates how oral contraceptive (OC) use influences blood metabolite levels and whether these changes are linked to increased cortisol levels.
  • In a sample of 391 premenopausal women, researchers found 27 metabolites significantly related to OC intake, with 25 of these results confirmed in a second cohort.
  • Notably, while certain metabolites were influenced by cortisol, others were unaffected, suggesting that understanding these metabolic changes could help identify women at higher risk for adverse effects related to OC use.
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Up-flow anaerobic bioreactors are widely applied for high-rate digestion of industrial wastewaters and rely on formation, and retention, of methanogenic granules, comprising of dense, fast-settling, microbial aggregates (approx. 0.5-4.

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Metabolite levels in urine may provide insights into genetic mechanisms shaping their related pathways. We therefore investigate the cumulative contribution of rare, exonic genetic variants on urine levels of 1487 metabolites and 53,714 metabolite ratios among 4864 GCKD study participants. Here we report the detection of 128 significant associations involving 30 unique genes, 16 of which are known to underlie inborn errors of metabolism.

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A complex interplay between genetic and environmental factors determines the individual risk of depressive disorders. Vitamin D has been shown to stimulate the expression of the tryptophan hydroxylase 2 (TPH2) gene, which is the rate-limiting enzyme for serotonin production in the brain. Therefore, we investigate the hypothesis that serum vitamin D levels moderate the interaction between the serotonin transporter promotor gene polymorphism (5-HTTLPR) and childhood abuse in depressive disorders.

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Background: Parkinson's disease (PD) is a systemic disease clinically defined by the degeneration of dopaminergic neurons in the brain. While alterations in the gut microbiome composition have been reported in PD, their functional consequences remain unclear. Herein, we addressed this question by an analysis of stool samples from the Luxembourg Parkinson's Study (n = 147 typical PD cases, n = 162 controls).

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