Single-cell sequencing reveals heterogeneity effects of bisphenol A on zebrafish embryonic development.

The embryonic period is a sensitive window for bisphenol A (BPA) exposure. However, embryonic development is a highly dynamic process with changing cell populations. The heterogeneity effects of BPA on fish embryo cells during development remain unclear. We applied single-cell RNA sequencing to analyze the impact of BPA exposure on transcriptome heterogeneity of 64683 cells from zebrafish embryos at 8, 12, and 30 hours post-fertilization (hpf). Thirty-eight cell populations were identified and gene expression profiles of 16 cell populations were significantly altered by BPA. At 8 hpf, BPA mainly influenced the outer layer cell populations of embryos, such as neural plate border and enveloping layer cells. At 12 and 30 hpf, nervous system formation and heart morphogenesis were disturbed. The altered differential processes of the neural plate border, neural crest, and neuronal cells were found to lead to increased neurogenesis in zebrafish larval. In the forebrain, midbrain, neurons, and optic cells, pathways related to cell division and DNA replication and repair were altered. Moreover, BPA also changed TGF beta signaling and heart tube morphogenesis in heart cells, leading to a decreased heartbeat in zebrafish larvae. Our study provides a comprehensive understanding of BPA toxicity on fish embryonic development at a single-cell level.