Paternal microplastic exposure alters sperm small non-coding RNAs and elicits offspring metabolic dysfunctions in mice

Microplastics (MPs) has been known for its toxicity on various organs and cells in humans, and its exposure leading to disease. Nevertheless, the toxic effects and underlying mechanisms on the profile of small non-coding RNAs (sncRNAs) in sperm, as well as their effects on embryo development, are not well understood. We recently developed the novel RNA sequencing (RNA-seq) technique, PANDORA-seq to overcome the limitations of traditional RNA sequencing. In this study, we elucidated the sncRNA changes using PANDORA-seq in mouse sperm after four weeks of oral gavage with MPs. We also examined the effects of sncRNAs on mouse embryonic stem cells (mESCs). MP exposure significantly altered sncRNA biogenesis-related genes in the testis and cauda epididymis, but not in the caput epididymis. PANDORA-seq revealed that a sncRNA landscape including transfer RNA-derived small RNAs (tsRNAs) and ribosomal RNA-derived small RNAs (rsRNAs) in the sperm was changed by MPs gavage. Interestingly, transfections of changed sncRNA, tsRNA-Glu-CTC and 5S ribosomal RNA (5S rRNA), in mESC changed pluripotency, inflammation, and cardiovascular development related genes. In conclusion, exposure to MPs may alter the sncRNA profile in sperm, which could affect embryonic development and increase the risk of inheritable diseases such as atherosclerosis and metabolic disorders. Overall design: To investigate the potential effects of MPs exposure on offspring health, 8-week-old male C57BL/6J WT mice were orally gavaged with either water or 10 mg/kg body weight/day of polystyrene microplastics (MPs, 1.1 µm mean particle size) for 4 weeks before mating with 12-week-old unexposed female WT mice. We profiled the sncRNA changes using PANDORA-seq in mouse sperm after 4 weeks of oral gavage with MPs to link the metabolic phenotype observed in F0 males with their offsprings. In addition, we also examined the effects of altered sncRNAs on mouse embryonic stem cells (mESCs).