Characterization of 2,2’,4,4’-tetrabromodiphenyl ether(BDE47)-induced testicular toxicity via single-cell RNA-sequencing

Background:The growing male reproductive diseases have been linked to higher exposure to certain environmental compounds such as 2,2,4,4-tetrabromodiphenyl ether(BDE47)that are widely distributed in the food chain.However,the specific underlying molecular mechanisms for BDE47-induced male reproductive toxicity are not completely understood.Methods:Here,for the first time,advanced single-cell RNA sequencing(ScRNA-seq)was employed to dissect BDE47-induced prepubertal testicular toxicity in mice from a pool of 76859 cells.Results:Our ScRNA-seq results revealed shared and heterogeneous information of differentially expressed genes,signaling pathways,transcription factors,and ligands-receptors in major testicular cell types in mice upon BDE47 treatment.Apart from disruption of hormone homeostasis,BDE47 was discovered to downregulate multiple previously unappreciated pathways such as double-strand break repair and cytokinesis pathways,indicative of their potential roles involved in BDE47-induced testicular injury.Interestingly,transcription factors analysis of ScRNA-seq results revealed that Kdm5b(lysine-specific demethylase 5B),a key transcription factor required for spermatogenesis,was downregulated in all germ cells as well as in Sertoli and telocyte cells in BDE47-treated testes of mice,suggesting its contribution to BDE47-induced impairment of spermatogenesis.Conclusions:Overall,for the first time,we established the molecular cell atlas of mice testes to define BDE47-induced prepubertal testicular toxicity using the ScRNA-seq approach,providing novel insight into our understanding of the underlying mechanisms and pathways involved in BDE47-associated testicular injury at a single-cell resolution.Our results can serve as an important resource to further dissect the potential roles of BDE47,and other relevant endocrine-disrupting chemicals,in inducing male reproductive toxicity.