Role of non-coding RNA in the pathogenesis of depression.

Depression is increasingly threatening human health as a serious psychological problem. However, it is remarkable that the precise mechanism underlying depression remains unelucidated. Recent studies have clarified that non-coding RNA, including but not limited to microRNA, long non-coding RNA, and circular RNA, plays an important role in the pathogenesis of depression. The research results cited in this paper reveal the origin, expression, distribution, function, and mechanism of microRNA in the nervous system. MicroRNA is involved in regulation of life activities, including growth, immune reaction, haematopoiesis, and metabolism, which are significant for maintaining normal physiological functions. Moreover, microRNA plays an important role in cell death and proliferation, development of cancer, and disease prognosis. Here, we also introduce the general research status of long non-coding RNA and circular RNA. Next, descriptive study methods, including fluorescence quantitative polymerase chain reaction, northern blot, microarray technology, RNA-seq, and fluorescent in situ hybridization are discussed. Functional study methods are also summarized and divided into gain- and loss-of-function studies. Moreover, the roles of non-coding RNA in the pathogenesis of depression, including neurogenesis, synaptic plasticity, brain-derived neurotrophic factor expression, HPA axis regulation, neurotransmission, neuropeptide expression, neuro-inflammation, and polyamine synthesis are discussed. Nevertheless, many unknown associations between non-coding RNA and depression remain to be clarified.