Biology subjects

Watson, E. D.

Publications and source records attributed to Watson, E. D..

4 recordsLinked to original sources

bioRxiv2023

Folate depletion alters mouse trophoblast stem cell regulation in vitro

Maternal folate deficiency increases risk of congenital malformations, yet its effect on placenta development is unclear. Here, we investigated how folate-depleted culture medium affects the developmental potential of mouse trophoblast stem cells (TSCs). When cultured in stem cell conditions, TSC viability was unaffected by folate depletion, but ectopic differentiation of several trophoblast cell subtypes occurred. When cultured in conditions that promote differentiation, folate-depleted TSCs were driven towards a syncytiotrophoblast cell fate potentially at the expense of other lineages. Additionally, trophoblast giant cell nuclei were small implicating folate in the regulation of endoreduplication. Therefore, dietary folate intake likely promotes placenta development.

developmental biology↗

bioRxiv2023

One-carbon metabolism is required for epigenetic stability in the mouse placenta

One-carbon metabolism, including the folate cycle, has a crucial role in fetal development though its molecular function is complex and unclear. The hypomorphic Mtrrgt allele is known to disrupt one-carbon metabolism, and thus methyl group availability, leading to several developmental phenotypes (e.g., neural tube closure defects, fetal growth anomalies). Remarkably, previous studies showed that some of the phenotypes were transgenerationally inherited. Here, we explored the genome-wide epigenetic impact of one-carbon metabolism in placentas associated with fetal growth phenotypes and determined whether specific DNA methylation changes were inherited. Firstly, methylome analysis of Mtrrgt/gt homozygous placentas revealed genome-wide epigenetic instability. Several DMRs were identified including at the Cxcl1 gene promoter and at the En2 gene locus, which may have phenotypic implications. Importantly, we discovered hypomethylation and ectopic expression of a subset of ERV elements throughout the genome of Mtrrgt/gt placentas with broad implications for genomic stability. Next, we determined that sperm DMRs in males from the Mtrrgt model were reprogrammed in the placenta with little evidence of direct or transgenerational germline DMR inheritance. However, some sperm DMRs were associated with placental gene misexpression despite normalisation of DNA methylation, suggesting the inheritance of an alternative epigenetic mechanism. Integration of published histone ChIP-seq datasets with sperm methylome and placenta transcriptome data from the Mtrrgt model point towards H3K4me3 deposition at key loci suggesting that histone modifications might play a role in epigenetic inheritance in this context. This study sheds light on the mechanistic complexities of one-carbon metabolism in development and epigenetic inheritance.

developmental biology↗

bioRxiv2021

Disruption of folate metabolism causes poor alignment and spacing of mouse conceptuses for multiple generations

Abnormal uptake or metabolism of folate increases risk of human pregnancy complications, though the mechanism is unclear. Here, we explore how defective folate metabolism influences early development by analysing mice with an Mtrrgt hypomorphic mutation. MTRR is necessary for methyl group utilisation from the folate cycle, and the Mtrrgt allele disrupts this process. We show that the spectrum of phenotypes previously observed in Mtrrgt/gt conceptuses at embryonic day (E) 10.5 is apparent from E8.5 including developmental delay, congenital malformations, and placental phenotypes (e.g., eccentric chorioallantoic attachment). Notably, we report misalignment of some Mtrrgt conceptuses within their implantation sites from E6.5. The degree of skewed growth occurs across a continuum, with eccentric chorioallantoic attachment now re-characterised as a severe form of conceptus misalignment. Additionally, some Mtrrgt/gt conceptuses display twinning. Therefore, we implicate folate metabolism in blastocyst orientation and spacing at implantation. Embryo development is influenced by skewed growth since developmental delay and heart malformations (but not neural tube defects) associate with severe misalignment of Mtrrgt/gt conceptuses. Patterning of trophoblast lineage markers is largely unaffected in skewed Mtrrgt/gt conceptuses at E8.5 indicating trophoblast differentiation was normal when misaligned. Typically, the uterus guides conceptus orientation. Accordingly, we manipulate the maternal Mtrr genotype and assess conceptus alignment. Mtrr+/gt, and Mtrrgt/gt mothers, plus Mtrr+/+ mothers, exhibit misaligned conceptuses at E6.5. While progesterone and/or BMP2 signalling required for decidualisation might be disrupted, normal gross decidual morphology, patterning, and blood perfusion is evident regardless of conceptus alignment, arguing against a uterine defect. Given the important finding that Mtrr+/+ mothers also display conceptus misalignment, a grandparental effect is explored. Multigenerational phenotype inheritance is characteristic of the Mtrrgt model, though the mechanism remains unclear. Genetic pedigree analysis reveals that severe skewing associates with the Mtrr genotype of either maternal grandparent. Moreover, misalignment is independent of the uterus and instead is attributed to an embryonic mechanism based on blastocyst transfer experiments. Overall, our data indicates that abnormal folate metabolism influences conceptus orientation over multiple generations with implications for subsequent development. Our study casts light on the complex role of folate metabolism during development beyond a direct maternal effect.

developmental biology↗

bioRxiv2020

Disruption of folate metabolism causes germline epigenetic instability and distinguishes HIRA as a biomarker of maternal transgenerational epigenetic inheritance

The mechanism behind transgenerational epigenetic inheritance (TEI) is unclear, particularly through the maternal grandparental line. We previously showed that disruption of folate metabolism in mice by the Mtrrgt hypomorphic mutation results in TEI of congenital malformations. Either maternal grandparent can initiate this phenomenon, which persists for at least four wildtype generations. In this work, we use a genome-wide approach to reveal genetic stability in the Mtrrgt model and epigenome-wide differential DNA methylation in the germline of Mtrr+/gt maternal grandfathers. While epigenetic reprogramming occurs, wildtype grandprogeny and great grandprogeny exhibit transcriptional memory of germline methylation defects. One region encompasses the Hira gene, which is misexpressed in embryos at least until the F3 generation in a manner that distinguishes Hira transcript expression as a biomarker of maternal phenotypic inheritance.

genomics↗