TITLE: FUNCTIONAL RNA MODIFICATIONS, MICRONUTRIENT EXPOSURE, DEVELOPMENTAL DISABILITIES PROJECT SUMMARY This proposal will combine the strengths of experimental mouse model with human prospective birth cohort study and transdisciplinary expertise to test novel hypotheses that functional RNA methylation (coupled with DNA methylation) may be one of the mechanisms underlying the association between maternal folate status and child risk of autism spectrum disorders (ASD). The role of maternal folate status in child risk of ASD has received great attention and is in debate. While many studies suggest beneficial effect of higher maternal folate intake against autism, a few studies raised concern about the potential harm of high prenatal folate intake. In the Boston Birth Cohort (BBC), PI's group demonstrated a wide variation of maternal folate levels, ranging from insufficiency to excess, which is consistent with the finding in NHANES, a U.S. nationally representative sample. A `U shaped' relationship was found between frequency of maternal multivitamin supplementation and ASD risk; this association was further supported by the findings based on measured maternal plasma folate levels. Furthermore, the preliminary data from PI's group suggest that maternal folate intake may have an impact on RNA methylation metabolism.
Two specific aims were proposed:
Aim1 will determine folate-associated alterations in RNA methylation and RNA/DNA methylation dynamics using mouse neural stem cells (NSCs). RNA/DNA methylation profiles will be determined using transcriptome-wide and genome-wide bisulfite sequencing, protein translation will be determined using polysome profiling, and folate-associated alterations in NSC proliferation and differentiation will be characterized. In-utero folate exposure-associated RNA/DNA methylation alterations will be determined using a mouse model.
Aim 2 will determine RNA methylation sites associated with in-utero folate exposure in cord blood samples. The inter-relationship of prenatal folate status, RNA/DNA methylation, and child risk of ASD will be determined via the integration of individual clinical features with corresponding RNA methylation and DNA methylation information. This proposed study, if successful, will provide new insight on how environmental exposures (here folate is used as an example) are involved in the functional activities of RNA modifications and RNA/DNA methylation dynamics, which in turn, may be associated with adverse health outcomes (here ASD is used as an example). The methodologies developed will be helpful to investigate molecular underpinnings of other micronutrients or toxicants on other health outcomes.
The potential harm of folate excess and underlying molecular mechanisms warrant careful exploration given that all the pregnant women are recommended to take prenatal folic acid supplement and US is a country with mandatory folic acid grain fortification. If this finding is further confirmed, optimizing maternal folate levels preconception and during pregnancy holds promise to improve child neuro-developmental outcomes, in addition to other known beneficial health effects.
