Role of hexosamine biosynthesis pathway-mediated O-GlcNAcylation in abnormal zebrafish embryonic development induced by perfluorooctane sulfonate exposure

Objective To investigate the effects of perfluorooctane sulfonate(PFOS) exposure on embryonic development and its possible mechanism by constructing a model of PFOS zebrafish infection.

Methods The PFOS concentration gradients (0, 0.02, 0.2, 2, and 20 μmol/L) were established based on human internal exposure levels, and exposed to zebrafish embryos for 120 hours post fertilization, then the basic indicators of zebrasish (hatching rate, malformation rate, mortality rate, heart rate, and motor ability) were measured. The global metabolic changes of zebrafish embryos exposed to PFOS were measured through non-targeted metabolomics technology. The expression of differential metabolic enzymes and proteins was determined by real-time quantitative PCR (RT-qPCR) and western blot.

Results Exposure to 20 μmol/L PFOS significantly increased the malformation rate (P < 0.05), heart rate (P < 0.05), and motor abnormalities (P < 0.05) of zebrafish embryos. The metabolomics analysis showed that in the 20 μmol/L PFOS exposure group, the levels of glucose-6-phosphate(Glu-6-P), N-acetylglucosamine(GlcNAc), and N-acetylglucosamine-6-phosphate(GlcNAc-6-P) were significantly increased, indicating the hyperactivation of hexosamine biosynthesis pathway (HBP). RT-qPCR demonstrated that the gene expression levels of HBP-related key metabolic enzymes (slc2a1b, hk1, and gfat1) were significantly up-regulated in 20 μmol/L PFOS group. Western blot showed that there was a significant difference in the global O-linked N-acetylglucosaminylation (O-GlcNAc) level between the 20 μmol/L PFOS group and the control group.

Conclusion PFOS exposure may interfere with HBP to mediate change of O-GlcNAcylation level, resulting in increased malformation and motor abnormalities in zebrafish embryos, suggesting that PFOS is toxic to embryonic development.