Introduction: Long non-coding RNAs (lncRNAs) are a type of RNA with length greater than 200 nucleotides and play crucial roles in many biological processes and disease including modulation of apoptosis, neuronal development, muscle differentiation, carcinogenesis, and immune responses.
LncRNAs are expressed in various tissues, the majority they express in the brain. Several recent studies demonstrated that LncRNAs are dysregulated in CNS disorders. Therefore, they play an important role in human health and new therapeutic strategies such as employing RNA interference (RNAi) can be recruited to target dysregulation lncRNA in CNS disorders.
Methods: lncRNAs are implicated in controlling transcription through the inhibition or recruitment of transcription factors, by regulating alternate splicing of the mRNA transcript, by interacting with chromatin to influence the DNA structure and epigenetic state, and by affecting the translation and stability of mRNA via binding to complementary transcripts or removing miRNA.
In the adult and developing brain, lncRNAs often show precise temporal and spatial patterns of expression and this specificity of expression declares that lncRNAs have key roles in CNS development and function. Long non-coding RNAs (lncRNAs) are reported to have been established roles in the pathogenesis of neuropsychiatric disorders including bipolar disorder (BD).
Results: BD is a debilitating psychiatric disorder diagnosed by recurrent episodes of disturbances in mood and activity of the patients. Prevalence of BD is up to 2% and are estimated to be the seventeenth leading cause of disability worldwide. This disorder leads to premature death (in part owing to suicide). The diagnosis of BD is often challenging due to its clinical heterogeneity and, consequently, delays in diagnosis are common. In addition, the response to current therapies is rarely complete and severe adverse reactions may occur.
Conclusion: Therefore, the assessment expression profile of lncRNAs that are involved in neuronal pathways is imperative as diagnostic biomarkers and therapeutic targets in BD patients. However, so far, only a few lncRNAs have been investigated at the functional or molecular levels in BD patients. It may be due to limitations such as assess the genes in the serum or cerebrospinal fluid and post-mortem brain samples, sample size, as well as, the effects of drugs on gene expression. Further analyses should be performed to identify, characterize and clarify the significant functions of lncRNAs in the neurobiology and pathology of BD at a molecular level and use them as clinical biomarkers and therapeutic targets.