MicroRNAs (miRNAs) are small non-coding RNA molecules, approximately 22 nucleotides in length, that regulate gene translation through silencing or degradation of target mRNAs. They are involved in multiple biological processes, including differentiation and proliferation, metabolism, hemostasis, apoptosis or inflammation, and in pathophysiology of many diseases. Numerous studies have suggested circulating miRNAs as promising diagnostic and prognostic biomarkers of many diseases.
miR-191 is expressed as a part of the miR-191/425 cluster on human chromosome 3.
miR-191 is developmentally regulated; significantly higher levels of miR-191 were found in human prefrontal cortex specimens from individuals older than 41 years compared to samples from individuals under 15 years. It was suggested that miR-191-mediated downregulation of a brain-derived neurotrophic factor may contribute to cortical development.
miR-191 was found to be significantly downregulated during terminal erythroid differentiation while its overexpression inhibited erythroid enucleation and chromatin condensation, suggesting that miR-191 plays a crucial role in erythropoiesis. miR-191 was also found to be differentially expressed in monocytes vs. monocyte-derived dendritic cells.
Changes in miR-191 expression have been reported in various malignancies such as breast, colon, lung, liver, prostate, pancreas, stomach, and ovarian cancer, pituitary adenoma, esophageal squamous carcinoma, oral squamous carcinoma, osteosarcoma, bladder, anaplastic large cell lymphoma, acute myeloid leukemia, severe medulloblastoma, retinoblastoma, thyroid follicular tumor, male breast cancer and melanoma.
Besides cancer, aberrant expression and functional abnormalities of miR-191 have been reported in a variety of other diseases, too. miR-191 may be a diagnostic biomarker that could help to distinguish Crohn’s disease from ulcerative colitis. Similarly, miR-191 was shown to be a potential biomarker for pulmonary hypertension, enabling its early detection and also, indicating the disease severity. miR-191 was also found to be induced in nephrotic syndrome in children, which makes it a potential diagnostic marker for this disease.
- References to miR-191-5p