Project description:Our early life environment has a profound influence on developing organs and tissues that impacts metabolic function, and determines health and disease susceptibility across the life-course. We show an adverse early-life exposure that causes metabolic dysfunction in adulthood reprograms active and repressive histone marks in the developing liver to accelerate acquisition of an adult epigenomic signature at specific genes and chromatin states. This epigenomic reprogramming persists long after the initial exposure, but remarkably, can remain transcriptionally- and metabolically-silent until later-life exposure to a Western-style (high fat-fructose-cholesterol) diet. These findings reveal the importance of epigenome:environment interactions across the life-course, which early in life accelerate epigenomic aging and reprogram the epigenome, and later in adulthood, can unlock metabolically restriced epigenetic reprogramming to drive metabolic dysfunction.
Project description:Background: Exposure to persistent organic pollutants (POPs) and disruptions in the gastrointestinal microbiota have been positively correlated with a predisposition to factors such as obesity, metabolic syndrome, and type 2 diabetes; however, it is unclear how the microbiome contributes to this relationship.
Objective: This study aimed to explore the association between early-life exposure to a potent aryl hydrocarbon receptor (AHR) agonist and persistent disruptions in the microbiota, leading to impaired metabolic homeostasis later in life.
Methods: This study utilized metagenomics, NMR- and mass spectrometry-based metabolomics, and biochemical assays to analyze the gut microbiome composition and function, as well as the physiological and metabolic effects of early-life exposure to 2,3,7,8-tetrachlorodibenzofuran (TCDF) in conventional, germ-free (GF), and Ahr-null mice. The impact of TCDF on Akkermansia muciniphila (A. muciniphila) in vitro was assessed using optical density (OD 600), flow cytometry, transcriptomics, and mass spectrometry-based metabolomics.
Results: TCDF-exposed mice exhibited disruption in the gut microbiome community structure and function, characterized by lower abundances of A. muciniphila, lower levels of cecal short chain fatty acids (SCFAs) and indole-3-lactic acid (ILA), and a reduction in gut hormones GLP-1 and PYY. Importantly, microbial and metabolic phenotypes associated with early-life POP exposure were transferable to GF recipients in the absence of POP carry-over. In addition, AHR-independent interactions between POPs and the microbiota were observed, significantly affected the growth, physiology, gene expression, and metabolic activity of A. muciniphila, resulting in suppressed activity along the ILA pathway.
Conclusions: These data point to the complex effects of POPs on the host and microbiota, providing strong evidence that early-life, short-term, and self-limiting POP exposure can adversely impact the microbiome, persisting into later life with associated health implications.
Project description:Our early life environment has a profound influence on developing organs and tissues that impacts metabolic function, and determines health and disease susceptibility across the life-course. We show an adverse early-life exposure that causes metabolic dysfunction in adulthood reprograms active and repressive histone marks in the developing liver to accelerate acquisition of an adult epigenomic signature at specific genes and chromatin states. This epigenomic reprogramming persists long after the initial exposure, but remarkably, can remain transcriptionally- and metabolically-silent until later-life exposure to a Western-style (high fat-fructose-cholesterol) diet. These findings reveal the importance of epigenome:environment interactions across the life-course, which early in life accelerate epigenomic aging and reprogram the epigenome, and later in adulthood, can unlock metabolically restriced epigenetic reprogramming to drive metabolic dysfunction.
Project description:Vancomycin is a broad-spectrum antibiotic widely used in cases of suspected sepsis in premature neonates. While appropriate and potentially lifesaving in this setting, early life antibiotic exposure alters the developing microbiome and is associated with increased risk of deadly complications, including late-onset sepsis (LOS) and necrotizing enterocolitis (NEC). Recent studies show that neonatal vancomycin treatment disrupts postnatal enteric nervous system (ENS) development in mouse pups, which is in part dependent upon neuro-immune interactions. This suggests that early life antibiotic exposure could disrupt these interactions in the neonatal gut. Notably, a subset of tissue-resident intestinal macrophages, muscularis macrophages, have been identified as important contributors to the development of the postnatal ENS. We hypothesized that vancomycin-induced neonatal dysbiosis impacts postnatal ENS development through effects on macrophages. Using a mouse model, we found that exposure to vancomycin in the first ten days of life, but not in adult mice, resulted in an expansion of pro-inflammatory colonic macrophages by increasing the recruitment of bone-marrow derived macrophages. Single cell RNA sequencing of neonatal colonic macrophages revealed that early-life vancomycin exposure was associated with an increase in immature and inflammatory macrophages, consistent with an influx of circulating monocytes differentiating into macrophages. Lineage tracing confirmed that vancomycin significantly increased non-yolk sac derived macrophage population. Consistent with these results, early life vancomycin exposure did not expand the colonic macrophage population nor decrease enteric neuron density in CCR2 deficient mice. Collectively, these findings demonstrate that early life vancomycin exposure alters macrophage number and phenotypes in distinct ways compared to vancomycin exposure in adult mice and results in altered ENS development.
Project description:Epithelial cell juntion integrity is thought to play an important role in the pathogenesis of inflammatory bowel disease (IBD). Early life stressors are suspected to impact epithelial barrier function later in life. We postulated that based on our previous findings that early life exposure to an inflammatory event could lead to epigegenetic changes mediating an exagerated response to a second inflammatory insult as an adult. In addition, we hypothesized that this increased inflammatory response could be mediated by alterations in miRNA expression impacting essential junction protein E-cadherin.
Project description:Microbial exposure during development can elicit long-lasting effects on the health of an individual. However, how microbial exposure in early life leads to permanent changes in the immune system is unknown. Here, we show that the microbial environment alters the setpoint for immune susceptibility by altering the developmental architecture of the CD8+ T cell compartment. In particular, early microbial exposure results in the preferential expansion of highly responsive fetal-derived CD8+ T cells that persist into adulthood and provide the host with enhanced immune protection against intracellular pathogens. Interestingly, microbial education of fetal-derived CD8+ T cells occurs during thymic development rather than in the periphery and involves the acquisition of a more effector-like epigenetic program. Collectively, our results provide a new conceptual framework for understanding how microbial colonization in early life leads to lifelong, and potentially irreversible, changes in the immune system.
Project description:Early life environmental exposure, particularly during perinatal period, can have a lifelong impact on organismal development and physiology. The biological rationale for this phenomenon is to promote physiological adaptation to the anticipated environment based on early life experience. However, perinatal exposure to adverse environments can also be associated with adult-onset disorders. Multiple environmental stressors induce glucocorticoids, which prompted us to investigate their role in developmental programming. Here, we report that perinatal glucocorticoid exposure had long-term consequences and resulted in diminished CD8 T cell response in adulthood and impaired control of tumor growth and bacterial infection. We found that perinatal glucocorticoid exposure resulted in persistent alteration of the hypothalamic-pituitaryadrenal (HPA) axis. Consequently, the level of the hormone in adults was significantly reduced, resulting in decreased CD8 T cell function. Our study thus demonstrates that perinatal stress can have long-term consequences on CD8 T cell immunity by altering HPA axis activity.
Project description:Reduced representation bisulfite sequencing was used to explore differentially methylated regions and sites within the amygdala of female rat offspring during earlylife and adulthood, in response to maternal high fat diet exposure. DMRs shared across early life and adulthood included pathways involved in neurodevelopment and genes regulating the DNMT machinery and protein function. To our knowledge, this is the first study to identify persistent genome-wide DNA methylation modifications associated with mHFD exposure in offspring from early life to adulthood.