Impact of urban exposures during pregnancy on placental small non-coding RNAs

BACKGROUND AND AIM: Epidemiological studies show that urban exposures (e.g., air pollution, built and natural environment, and noise) during pregnancy could adversely influence the developing foetus. Although the underlying mechanisms are unclear, recent findings suggest that placental transcriptome can be a proxy of placental function during pregnancy and a plausible mediator of the association between intrauterine environmental exposures and foetal growth and development, and childhood and adult health trajectories. In particular, there is an increasing interest in small non-coding(nc)RNAs, including microRNAs (miRNAs), which are regulatory RNAs critical for placenta function and foetal development. Our main aim is to assess the association of several urban exposures during pregnancy with placental small ncRNA profiles in the Barcelona Life Study cohort (BiSC). METHODS: BiSC is a population-based birth cohort of 1,086 mother-child pairs from the Barcelona metropolitan area (2018 onwards). We will characterize exposure to air pollution, noise, green space, and built environment as indicators of the urban exposome. Placental RNA was obtained from 450 placental foetal villi biopsies. Small ncRNA profiles were measured by RNA-sequencing (library insert of 17-52 nucleotides length, 50 nucleotides sequencing length, and 5M reads/sample). Quality control, processing of RNA-sequencing data, and small ncRNAs annotation and quantification will be done with the SeqCluster/SeqBuster bioinformatic tool. RESULTS: A pilot study of 8 samples identified a total of 550 small ncRNAs, 44% being miRNAs. MiRNAs of the placental specific C19MC cluster were found among the most abundant. In the ISEE Conference we will present the placental small ncRNA profiles and their association with urban-related exposures. CONCLUSIONS: Studying the impact of pregnancy exposures on the foetus and its biological intermediates is crucial to prevent their harmful effects and to develop biomarkers that allow early monitoring and treatment. KEYWORDS: transcriptomics, microRNAs, small non-coding RNAs, placenta, urban exposures, air pollution, built environment, noise