Role of LINE-1 in the nervous system and neurological disorders

Long interspersed nucleotide element-1 (LINE-1) is the only known reverse transcriptional transposon in the human genome with autonomous transposition capabilities. It can replicate and insert itself into new gene sites through the reverse transcription of transposons. The activation of LINE-1 is closely related to the occurrence and development of aging, cancer, and neurological diseases, and therefore has received widespread attention. However, research on LINE-1 in the nervous system is still in its early stages. Emerging evidence suggests that LINE-1 can undergo reverse transcriptional translocation and be regulated in neurons and neuroglial cells, playing a crucial role in neuronal diversity, neural plasticity, and behavioral phenotypes. In this review, we summarize the multifaceted functions of LINE-1 in neuronal function and evolution, synapse formation, and its implications for various neurological conditions, including neurodevelopmental disorders, neurodegenerative diseases, and emotional disorders. In addition, we also discuss the potential role of LINE-1 as a diagnostic biomarker and a therapeutic target in these neurological disorders. A comprehensive understanding of LINE-1's functions in the nervous system will enhance our insight into the pathogenesis of neurological diseases and may aid in the development of new therapeutic strategies.