Circular RNAs as biomarkers and therapeutic targets in environmental chemical exposure-related diseases.

Chemical contamination in the environment is known to cause abnormal circular RNA (circRNA) expression through multiple exposure routes; yet, the underlying molecular mechanisms remain unclear. Non-coding RNAs (ncRNAs), especially circRNAs, play important roles in epigenetic regulation and disease pathogenesis; however, few studies have examined the function of circRNAs in chemical contamination-induced diseases. CircRNAs are covalently closed continuous loops that do not possess 5' and 3' ends, increasing their structural stability and limiting degradation by exoribonucleases. In addition, environmental chemical exposure-related diseases are often accompanied by aberrant expression of specific circRNAs and those circRNAs are often detected in tissues and body fluids. Based on these characteristics, circRNAs may serve as candidate biomarkers for the diagnosis of diseases related to environmental chemical exposure. Here, we review the generation and function of circRNAs, and the possible molecular mechanisms underlying the regulation of environmental chemical exposure-related disorders by circRNAs. This is the first comprehensive review of the relationship between environmental chemical exposure and circRNAs in chemical exposure-induced diseases.