Circular RNAs: from biogenesis and function to diseases.

OBJECTIVE

Evidence suggests that various diseases may contribute to the circular RNAs (circRNAs) expression disorder. This review was aimed at looking for appropriate biomarkers for the treatment of diseases.

DATA SOURCES

The comprehensive search used online literature databases including PubMed of National Center for Biotechnology Information and Web of Science.

STUDY SELECTION

The study selection was based on the following keywords: circRNAs, biogenesis, biologic function, and disease. The time limit for literature retrieval was from the year 1976 to 2019, with language restriction in English. Relevant articles were carefully reviewed, with no exclusions applied to study design and publication type.

RESULTS

CircRNAs are one of the critical non-coding RNAs (ncRNAs), which are covalently closed continuous loops that do not possess 5' and 3' ends. This makes them resistant to exoribonuclease activity and potentially more stable than their cognate linear transcripts, thus making them ideal candidates for biomarker development. Due to the stable and extensive tissue-specific expression of circRNAs, they can function as microRNA sponges and bind to RNA-binding proteins, regulate transcription and splicing, and translate into proteins to participate in the regulation of physiologic and pathologic processes. Moreover, the expression disorders of circRNAs in diseases, such as neurodegenerative disease, cardiovascular disease, and cancer, make them have potential applications for the diagnosis and treatment of diseases.

CONCLUSIONS

Changes in circRNA expression profiles related to various diseases, and circRNAs often exhibit low expression in cancer tissues. In addition, circRNAs can be detected in patient's body fluids to indicate that circRNAs are effective biomarkers for disease diagnosis. These characteristics make circRNAs have potential applications as novel therapeutic targets for diseases.