Roles of circular RNAs targeted to synapses: Narrative review of potential mechanisms and biomarkers

Circular RNAs are a class of non-coding RNAs that are widely expressed in eukaryotes and are characterized by tissue-specific and developmental stage-specific expression. In recent years, circular RNAs have garnered significant attention in the field of RNA biology. The abundant expression and stability of circular RNAs in brain tissue make them highly promising for research in neuroscience and clinical diagnostics. The purpose of this review is to explore the distribution and function of circular RNAs in brain tissue, their roles in neurological disorders, and to summarize the potential of circular RNAs as biomarkers for neurodegenerative disorders. Circular RNAs are widely expressed in brain tissue, with the highest levels observed in the fetal brain, and they are closely associated with the development and function of the nervous system. Circular RNAs play important roles in synaptic development, synaptic function, memory, and cognitive abilities, and they are involved in the pathogenesis of various neurodegenerative diseases by regulating pathways such as miRNA. Circular RNAs, due to their stability, can serve as potential biomarkers for neurological diseases, such as Alzheimer's disease, Parkinson's disease, and cerebral infarction. The expression changes of circular RNAs in these diseases have the potential for diagnosis and disease progression prediction, as these diseases are related to synaptic dysfunction and the decline of memory and cognitive abilities. Studying the role of circular RNAs in synaptic function and neurodegenerative diseases can help uncover the molecular mechanisms of neurodegenerative diseases and provide new strategies for precision medicine. The clinical application potential of circular RNAs as biomarkers needs further validation to realize their use in the early diagnosis and treatment of neurological diseases.