microRNA-9-5p (miR-9-5p)

microRNA‐9‐5p is a highly conserved small non-coding RNA (~22 nucleotides) generated from three distinct MIR‐9 genes located on different chromosomes. It is processed from primary precursors into a mature form that regulates gene expression post-transcriptionally by binding to complementary sequences within target mRNAs. This leads primarily to translational repression or transcript degradation. Highly expressed during embryonic neural development but also present in immune cells and various tumors, it plays key roles in neurogenesis, cell proliferation/differentiation/apoptosis balance, inflammation regulation through targets like NFκB1 and dopamine receptor D2,[1][3][4][5] as well as tumor progression/metastasis through targets such as E-cadherin and ABCC1 transporter protein. Its dysregulation has been implicated across multiple diseases including cancers (where it may act either as an oncogene or tumor suppressor), neurodegenerative disorders, inflammatory conditions like rheumatoid arthritis,[4] cardiovascular disease,[5] and metabolic syndromes such as type 2 diabetes mellitus. Circulating levels have diagnostic/prognostic value but its pleiotropic actions pose challenges for targeted therapy development.

Other names

miR-9miRNA-9hsa-miR-9-5p (for human)microRNA 9miR-9a (in Drosophila)

– Binds complementary sequences in the 3' UTRs of target mRNAs to suppress translation or induce degradation. – Regulates drug resistance by targeting ABCC1 transporter in glioma cells. – Modulates apoptosis-related genes such as Bax, Bcl‑2, cleaved caspase 3. – Regulates inflammatory pathways via NFκB signaling.