Project description:Growing evidence point towards a strong contribution of paternal factors in placental health with implications in adult-onset complex disease risk. We have recently demonstrated that paternal diet-induced obesity alters sperm histone methylation and is associated with metabolic disturbances in the next generation. Diet-sensitive epigenetic regions in sperm were found at genes involved in trophectoderm and placental development, and corresponded to epigenetic and gene expression profiles in these tissues. We sought to investigate whether paternal diet-induced obesity before conception can alter the placental transcriptome, and whether differential gene expression corresponds with sperm obesity-associated epigenetic signatures. C57BL6/J males were fed either a control or high-fat diet for 10 weeks beginning at 6 weeks of age. They were then bred to control-fed C57BL6/J females to induce pregnancies and E14.5 placentas were collected. RNA-sequencing was performed (n=4 per group per sex) to detect sex-specific transcriptional changes associated with paternal diet. At necropsy, sperm was collected for chromatin immunoprecipitation followed by sequencing (ChIP-seq; n=3 per group) targeting histone H3 lysine 4 tri-methylation (H3K4me3) to detect obesity-induced changes in H3K4me3 enrichment. There were sex-specific differentially expressed genes in placentas with some overlapping with promoters showing obesity-associated sperm epimutations. A deconvolution analysis using single-cell RNA-seq data from mouse E14.5 placenta (Han et al., Cell, 2018) revealed significant differences in trophoblast subtype proportions in placentas derived from HFD sires. This study highlights a previously underappreciated role of the placenta at the origin of paternally-induced metabolic disturbances in offspring.
Project description:Growing evidence point towards a strong contribution of paternal factors in placental health with implications in adult-onset complex disease risk. We have recently demonstrated that paternal diet-induced obesity alters sperm histone methylation and is associated with metabolic disturbances in the next generation. Diet-sensitive epigenetic regions in sperm were found at genes involved in trophectoderm and placental development, and corresponded to epigenetic and gene expression profiles in these tissues. We sought to investigate whether paternal diet-induced obesity before conception can alter the placental transcriptome, and whether differential gene expression corresponds with sperm obesity-associated epigenetic signatures. C57BL6/J males were fed either a control or high-fat diet for 10 weeks beginning at 6 weeks of age. They were then bred to control-fed C57BL6/J females to induce pregnancies and E14.5 placentas were collected. RNA-sequencing was performed (n=4 per group per sex) to detect sex-specific transcriptional changes associated with paternal diet. At necropsy, sperm was collected for chromatin immunoprecipitation followed by sequencing (ChIP-seq; n=3 per group) targeting histone H3 lysine 4 tri-methylation (H3K4me3) to detect obesity-induced changes in H3K4me3 enrichment. There were sex-specific differentially expressed genes in placentas with some overlapping with promoters showing obesity-associated sperm epimutations. A deconvolution analysis using single-cell RNA-seq data from mouse E14.5 placenta (Han et al., Cell, 2018) revealed significant differences in trophoblast subtype proportions in placentas derived from HFD sires. This study highlights a previously underappreciated role of the placenta at the origin of paternally-induced metabolic disturbances in offspring.
Project description:<p>The gut microbiota operates at the interface of host-environment interactions to influence human homeostasis and metabolic networks. Environmental factors that unbalance gut microbial ecosystems can therefore elicit physiological and disease-associated responses across somatic tissues. However, the systemic impact of the gut microbiome on the germline - and consequently on the F1 offspring it gives rise to - is unexplored. Here we show that the gut microbiota act as a key interface between paternal preconception environment and intergenerational health in mice. Perturbations to the gut microbiota of prospective fathers increase the probability of their offspring presenting with low birth weight, severe growth restriction and premature mortality. Transmission of disease risk occurs via the germline and is provoked by pervasive gut microbiome perturbations, including non-absorbable antibiotics or osmotic laxatives, but is rescued by restoring the paternal microbiota before conception. This effect is linked with a dynamic response to induced dysbiosis in the male reproductive system, including impaired leptin signalling, altered testicular metabolite profiles and remapped small RNA payloads in sperm. As a result, dysbiotic fathers trigger an elevated risk of in utero placental insufficiency, revealing a placental origin of mammalian intergenerational effects. Our study defines a regulatory ‘gut-germline axis’ in males, which is sensitive to environmental exposures and programs offspring fitness through impacting placental function.</p>
Project description:Maternal obesity alters placental tissue function and morphology with a corresponding increase in local inflammation. We and others showed that placenta size, inflammation and fetal growth are regulated by maternal diet and obesity status. Maternal obesity alters placental DNA methylation which in turn could likely impact gene transcription of of proteins critical for normal fetal development. RNA-binding motif single-stranded interacting protein 1 (RBMS1) is expressed by the placenta and likely modulates DNA replication and transcription regulation. Serum RBMS1 protein concentration is increased with maternal obesity and RBMS1 gene expression in liver tissue is induced by a high-fat diet and inflammation. However, it is not yet known whether placental RBMS1 mRNA expression and DNA methylation are altered by maternal obesity.
Project description:Maternal obesity is becoming a major health consideration for successful pregnancy outcomes. There is growing proof that maternal obesity has a negative influence on placental development and function, thereby adversely influencing offspring programming and health outcomes. However, the molecular mechanisms underlying these processes are so far poorly understood. We set out to analyse term placenta whole transcriptome in obese (n=5) and normoweight women (n=5), using Affymetrix microarray platform compromising of 50,000 probe sets. Our analysis shows that the placental transcriptome differs between normoweight and obese women. Different processes and pathways among placenta from obese women were dysregulated, including inflammation and immune responses, lipid metabolism, cell death and survival and cancer pathways, vasculogenesis and angiogenesis, and glucocorticoid receptor signaling pathway. Together, this global gene expression profiling approach demonstrates and confirms that maternal obesity creates a unique in utero environment that impairs placental transcriptome.
Project description:Obesity is a global rising problem with epidemiological dimension. Obese parents can have programming effects on their offspring leading to obesity and associated diseases in later life. This constitutes a vicious circle. Epidemiological data and studies in rodents demonstrated differential programming effects in male and female offspring, but the timing of their developmental origin is not known. This study investigated if sex-specific programming effects of parental obesity can already be detected in the pre-implantation period. Diet induced obese male or female mice were mated with normal-weight partners and blastocysts were recovered. Gene expression profiling revealed sex-specific responses of the blastocyst transcriptome to maternal and paternal obesity. The changes in the transcriptome of male blastocysts were more pronounced than those of female blastocysts, with a stronger impact of paternal than of maternal obesity. The sperm of obese mice revealed an increased abundance of several miRNAs compared to lean mice. Our study indicates that sex-specific programming effects of parental obesity already start in the pre‑implantation period and reveals specific alterations of the sperm miRNA profile as mechanistic link to programming effects of paternal obesity.
Project description:Obesity is a global rising problem with epidemiological dimension. Obese parents can have programming effects on their offspring leading to obesity and associated diseases in later life. This constitutes a vicious circle. Epidemiological data and studies in rodents demonstrated differential programming effects in male and female offspring, but the timing of their developmental origin is not known. This study investigated if sex-specific programming effects of parental obesity can already be detected in the pre-implantation period. Diet induced obese male or female mice were mated with normal-weight partners and blastocysts were recovered. Gene expression profiling revealed sex-specific responses of the blastocyst transcriptome to maternal and paternal obesity. The changes in the transcriptome of male blastocysts were more pronounced than those of female blastocysts, with a stronger impact of paternal than of maternal obesity. The sperm of obese mice revealed an increased abundance of several miRNAs compared to lean mice. Our study indicates that sex-specific programming effects of parental obesity already start in the pre‑implantation period and reveals specific alterations of the sperm miRNA profile as mechanistic link to programming effects of paternal obesity.
Project description:Parental environmental exposures can strongly influence descendant risks for adult disease. Metabolic disorders arise from the intersection of environmental and genetic risk factors, with epigenetic inheritance being at the center of the familial cycle of transgenerational disease. How paternal high-fat diet changes the sperm chromatin leading to the acquisition of metabolic disease in offspring remains controversial and ill-defined. Using a genetic model of epigenetic inheritance, we investigated the role of histone H3 lysine 4 methylation (H3K4me3) in the paternal transmission of metabolic dysfunction. We show that obesity-induced alterations in sperm H3K4me3 associated with offspring phenotypes and corresponded to embryonic and placental chromatin profiles and gene expression. Transgenerational susceptibility to metabolic disease was only observed when grandsires had a pre-existing genetic predisposition to metabolic dysfunction that was associated with enhanced alterations to sperm H3K4me3. This non-DNA based knowledge of inheritance has the potential to improve our understanding of how environment shapes heritability and may lead to novel routes for the prevention of disease.
Project description:Preconception parental environment can reproducibly program offspring phenotype without altering the DNA sequence, yet the mechanisms underpinning this ‘epigenetic inheritance’ remains elusive. Here, we demonstrate the existence of an intact piRNA-pathway in mature Drosophila sperm and show that pathway modulation alters offspring gene transcription in a sequence-specific manner. We map a dynamic small RNA content in developing sperm and find that the mature sperm carry a highly distinct small RNA cargo. By biochemical pulldown, we identify a small RNA subset bound directly to piwi protein. And, we show that piRNA-pathway controlled sperm small RNAs are linked to target gene repression in offspring. Critically, we find that full piRNA-pathway dosage is necessary for the intergenerational metabolic and transcriptional reprogramming events triggered by high paternal dietary sugar. These data provide a direct link between regulation of endogenous mature sperm small RNAs and transcriptional programming of complementary sequences in offspring. Thus, we identify a novel mediator of paternal intergenerational epigenetic inheritance.