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84 result(s) for "Moser, Dirk"
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Stress type–specific small extracellular vesicle signatures reflect divergent biological responses to acute psychosocial and physical challenges
Maladaptive stress responses are associated with a variety of psychological and physical disorders, often characterized by molecular indicators of dysregulated stress pathways. Small extracellular vesicles (sEVs), which play a key role in intercellular communication, may be critically involved in these processes. In this study, we quantified sEV concentrations (specifically CD9 + , CD63 + , and CD81 + markers) in the plasma of twenty young, healthy men before and after exposure to both acute psychosocial and physical stress, using imaging flow cytometry (IFCM). Both stressors induced significant increases in cortisol, catecholamines, and cell-free DNA (cfDNA) in all participants. sEVs, however, were elevated only after physical stress, showing a rapid rise particularly in CD9- and CD63-positive vesicles, followed by a return to baseline within 40 min. In contrast, psychosocial stress elicited highly heterogeneous, non-directional sEV responses. Recursive partitioning further revealed clearly distinct sEV patterns for psychosocial and physical stress, with the highest discriminatory power observed for CD44⁺ sEVs. These findings support the existence of stressor-specific sEV signatures that could serve as future biomarkers of individual stress experience and act as effectors of distinct signal transduction pathways in both psychosocial and physical stress.
Transgene Detection by Digital Droplet PCR
Somatic gene therapy is a promising tool for the treatment of severe diseases. Because of its abuse potential for performance enhancement in sports, the World Anti-Doping Agency (WADA) included the term 'gene doping' in the official list of banned substances and methods in 2004. Several nested PCR or qPCR-based strategies have been proposed that aim at detecting long-term presence of transgene in blood, but these strategies are hampered by technical limitations. We developed a digital droplet PCR (ddPCR) protocol for Insulin-Like Growth Factor 1 (IGF1) detection and demonstrated its applicability monitoring 6 mice injected into skeletal muscle with AAV9-IGF1 elements and 2 controls over a 33-day period. A duplex ddPCR protocol for simultaneous detection of Insulin-Like Growth Factor 1 (IGF1) and Erythropoietin (EPO) transgenic elements was created. A new DNA extraction procedure with target-orientated usage of restriction enzymes including on-column DNA-digestion was established. In vivo data revealed that IGF1 transgenic elements could be reliably detected for a 33-day period in DNA extracted from whole blood. In vitro data indicated feasibility of IGF1 and EPO detection by duplex ddPCR with high reliability and sensitivity. On-column DNA-digestion allowed for significantly improved target detection in downstream PCR-based approaches. As ddPCR provides absolute quantification, it ensures excellent day-to-day reproducibility. Therefore, we expect this technique to be used in diagnosing and monitoring of viral and bacterial infection, in detecting mutated DNA sequences as well as profiling for the presence of foreign genetic material in elite athletes in the future.
Stress type-specific small extracellular vesicle signatures reflect divergent biological responses to acute psychosocial and physical challenges Do I understand correctly that there were no queries regarding the manuscript?
Maladaptive stress responses are associated with a variety of psychological and physical disorders, often characterized by molecular indicators of dysregulated stress pathways. Small extracellular vesicles (sEVs), which play a key role in intercellular communication, may be critically involved in these processes. In this study, we quantified sEV concentrations (specifically CD9 , CD63 , and CD81 markers) in the plasma of twenty young, healthy men before and after exposure to both acute psychosocial and physical stress, using imaging flow cytometry (IFCM). Both stressors induced significant increases in cortisol, catecholamines, and cell-free DNA (cfDNA) in all participants. sEVs, however, were elevated only after physical stress, showing a rapid rise particularly in CD9- and CD63-positive vesicles, followed by a return to baseline within 40 min. In contrast, psychosocial stress elicited highly heterogeneous, non-directional sEV responses. Recursive partitioning further revealed clearly distinct sEV patterns for psychosocial and physical stress, with the highest discriminatory power observed for CD44⁺ sEVs. These findings support the existence of stressor-specific sEV signatures that could serve as future biomarkers of individual stress experience and act as effectors of distinct signal transduction pathways in both psychosocial and physical stress.
Event-related functional MRI of awake behaving pigeons at 7T
Animal-fMRI is a powerful method to understand neural mechanisms of cognition, but it remains a major challenge to scan actively participating small animals under low-stress conditions. Here, we present an event-related functional MRI platform in awake pigeons using single-shot RARE fMRI to investigate the neural fundaments for visually-guided decision making. We established a head-fixated Go/NoGo paradigm, which the animals quickly learned under low-stress conditions. The animals were motivated by water reward and behavior was assessed by logging mandibulations during the fMRI experiment with close to zero motion artifacts over hundreds of repeats. To achieve optimal results, we characterized the species-specific hemodynamic response function. As a proof-of-principle, we run a color discrimination task and discovered differential neural networks for Go-, NoGo-, and response execution-phases. Our findings open the door to visualize the neural fundaments of perceptual and cognitive functions in birds—a vertebrate class of which some clades are cognitively on par with primates. Functional magnetic resonance imaging (fMRI) is a powerful method to understand neural mechanisms of cognition but imaging of small animals can be challenging. The authors present an event-related fMRI platform to visualize the neural fundaments of perceptual and cognitive functions in awake birds.
The association between childhood maltreatment and empathic perspective taking is moderated by the 5-HTT linked polymorphic region: Another example of “differential susceptibility”
Previous research has suggested that the short (S)-allele of the 5-HT transporter gene-linked polymorphic region (5-HTTLPR) may confer \"differential susceptibility\" to environmental impact with regard to the expression of personality traits, depressivity and impulsivity. However, little is known about the role of 5-HTTLPR concerning the association between childhood adversity and empathy. Here, we analyzed samples of 137 healthy participants and 142 individuals diagnosed with borderline personality disorder (BPD) focusing on the 5-HTTLPR genotype (S/L-carrier) and A/G SNP (rs25531), in relation to childhood maltreatment and empathy traits. Whereas no between-group difference in 5-HTTLPR genotype distribution emerged, the S-allele selectively moderated the impact of childhood maltreatment on empathic perspective taking, whereby low scores in childhood trauma were associated with superior perspective taking. In contrast, L-homozygotes seemed to be largely unresponsive to variation in environmental conditions in relation to empathy, suggesting that the S-allele confers \"differential susceptibility\". Moreover, a moderation analysis and tests for differential susceptibility yielded similar results when transcriptional activity of the serotonin transporter gene was taken into account. In conclusion, our findings suggest that the S-allele of the 5-HTTLPR is responsive to early developmental contingencies for \"better and worse\", i.e. conferring genetic plasticity, especially with regard to processes involving emotional resonance.
Oxytocin and the stress buffering effect of social company: a genetic study in daily life
Social relationships are a crucial determinant of both mental and physical health. This effect is partly due to social buffering of stress. Animal studies suggest that social buffering is mediated via the oxytocin system, while studies in humans are sparse and limited by the low ecological validity of laboratory settings. In the present study, participants (N = 326) completed smartphone questionnaires four times a day over 4 to 5 days, measuring stressors, negative affect, and social context to assess social buffering. We found that under stress, participants reported a higher need for social company. Further, the impact of prior stressful events on momentary negative affect was attenuated by the perceived pleasantness of current social company. This social buffering effect was moderated by haplotypes of the oxytocin receptor gene, based on two well-described single nucleotide polymorphisms (rs2268498, rs53576). Effects were robust when controlling for gender and age, applying different data quality criteria, and even apparent in genotype-based analyses. Our findings demonstrate that social buffering and its modulation by oxytocin system characteristics have implications for life as lived outside the laboratory.
Epigenetics in Sports
The heritability of specific phenotypical traits relevant for physical performance has been extensively investigated and discussed by experts from various research fields. By deciphering the complete human DNA sequence, the human genome project has provided impressive insights into the genomic landscape. The hope that this information would reveal the origin of phenotypical traits relevant for physical performance or disease risks has proven overly optimistic, and it is still premature to refer to a ‘post-genomic’ era of biological science. Linking genomic regions with functions, phenotypical traits and variation in disease risk is now a major experimental bottleneck. The recent deluge of genome-wide association studies (GWAS) generates extensive lists of sequence variants and genes potentially linked to phenotypical traits, but functional insight is at best sparse. The focus of this review is on the complex mechanisms that modulate gene expression. A large fraction of these mechanisms is integrated into the field of epigenetics, mainly DNA methylation and histone modifications, which lead to persistent effects on the availability of DNA for transcription. With the exceptions of genomic imprinting and very rare cases of epigenetic inheritance, epigenetic modifications are not inherited transgenerationally. Along with their susceptibility to external influences, epigenetic patterns are highly specific to the individual and may represent pivotal control centers predisposing towards higher or lower physical performance capacities. In that context, we specifically review how epigenetics combined with classical genetics could broaden our knowledge of genotype-phenotype interactions. We discuss some of the shortcomings of GWAS and explain how epigenetic influences can mask the outcome of quantitative genetic studies. We consider epigenetic influences, such as genomic imprinting and epigenetic inheritance, as well as the life-long variability of epigenetic modification patterns and their potential impact on phenotype with special emphasis on traits related to physical performance. We suggest that epigenetic effects may also play a considerable role in the determination of athletic potential and these effects will need to be studied using more sophisticated quantitative genetic models. In the future, epigenetic status and its potential influence on athletic performance will have to be considered, explored and validated using well controlled model systems before we can begin to extrapolate new findings to complex and heterogeneous human populations. A combination of the fields of genomics, epigenomics and transcriptomics along with improved bioinformatics tools and precise phenotyping, as well as a precise classification of the test populations is required for future research to better understand the inter-relations of exercise physiology, performance traits and also susceptibility towards diseases. Only this combined input can provide the overall outlook necessary to decode the molecular foundation of physical performance.
No evidence for intervention-associated DNA methylation changes in monocytes of patients with posttraumatic stress disorder
DNA methylation patterns can be responsive to environmental influences. This observation has sparked interest in the potential for psychological interventions to influence epigenetic processes. Recent studies have observed correlations between DNA methylation changes and therapy outcome. However, most did not control for changes in cell composition. This study had two aims: first, we sought to replicate therapy-associated changes in DNA methylation of commonly assessed candidate genes in isolated monocytes from 60 female patients with post-traumatic stress disorder (PTSD). Our second, exploratory goal was to identify novel genomic regions with substantial pre-to-post intervention DNA methylation changes by performing whole-genome bisulfite sequencing (WGBS) in two patients with PTSD. Equivalence testing and Bayesian analyses provided evidence against physiologically meaningful intervention-associated DNA methylation changes in monocytes of PTSD patients in commonly investigated target genes ( NR3C1, FKBP5, SLC6A4, OXTR) . Furthermore, WGBS yielded only a limited set of candidate regions with suggestive evidence of differential DNA methylation pre- to post-therapy. These differential DNA methylation patterns did not prove replicable when investigated in the entire cohort. We conclude that there is no evidence for major, recurrent intervention-associated DNA methylation changes in the investigated genes in monocytes of patients with PTSD.
Highs and lows
Why people differ in their susceptibility to external events is essential to our understanding of personality, human development, and mental disorders. Genes explain a substantial portion of these differences. Specifically, genes influencing the serotonin system are hypothesized to be differential susceptibility factors, determining a person's reactivity to both positive and negative environments. We tested whether genetic variation in the serotonin transporter (5-HTTLPR) is a differential susceptibility factor for daily events. Participants (N = 326, 77% female, mean age = 25, range = 17-36) completed smartphone questionnaires four times a day over four to five days, measuring stressors, uplifts, positive and negative affect. Affect was predicted from environment valence in the previous hour on a within-person level using three-level autoregressive linear mixed models. The 5-HTTLPR fulfilled all criteria of a differential susceptibility factor: Positive affect in carriers of the short allele (S) was less reactive to both uplifts and stressors, compared to homozygous carriers of the long allele (L/L). This pattern might reflect relative affective inflexibility in S-allele carriers. Our study provides insight into the serotonin system's general role in susceptibility and highlights the need to assess the whole spectrum of naturalistic experiences.
Epigenetic regulation of lateralized fetal spinal gene expression underlies hemispheric asymmetries
Lateralization is a fundamental principle of nervous system organization but its molecular determinants are mostly unknown. In humans, asymmetric gene expression in the fetal cortex has been suggested as the molecular basis of handedness. However, human fetuses already show considerable asymmetries in arm movements before the motor cortex is functionally linked to the spinal cord, making it more likely that spinal gene expression asymmetries form the molecular basis of handedness. We analyzed genome-wide mRNA expression and DNA methylation in cervical and anterior thoracal spinal cord segments of five human fetuses and show development-dependent gene expression asymmetries. These gene expression asymmetries were epigenetically regulated by miRNA expression asymmetries in the TGF-β signaling pathway and lateralized methylation of CpG islands. Our findings suggest that molecular mechanisms for epigenetic regulation within the spinal cord constitute the starting point for handedness, implying a fundamental shift in our understanding of the ontogenesis of hemispheric asymmetries in humans.