microRNAs regulate all the cellular processes, and are strongly involved in differentiation of stem cells. Disturbances in the regulation of microRNAs expression and activity may deviate the stem cells fate, impairing their differentiation and contributing to diseases initiation or progression. In this talk the role of microRNAs in certain neurological conditions will be discussed.
5-aminosalicylic acid (5-ASA) is commonly used as the first-line treatment for ulcerative colitis (UC). In this study, we show that the mechanism responsible for the protective effect of 5-ASA is associated with the modulation of non-coding microRNA molecule (miRNA) expression. Stimulation of human intestinal epithelial cells (Caco-2) with 1000 µM of 5-ASA suppressed the levels of miR-125b, miR-150, miR-155, miR-346 and miR-506, which are known to be involved in the regulation of colitis and/or colorectal cancer in patients with inflammatory bowel disease. The 5-ASA-induced inhibitions of these miRNAs were associated with significant inductions of their target genes such as vitamin D receptor (VDR), suppressor of cytokine signaling (SOCS1), Forkhead box O (FOXO3a) and DNA methyltransferase 1 (DNMT1). The relationships between the selected miRNAs and their target genes were further confirmed in Caco-2 cells transfected of with specific miRNA inhibitors or miRNA mimics. Moreover, we showed that 5-ASA has the potential to hinder miR-155 expression induced by the transfection of miR-155 mimic into Caco-2 cells. These findings underline the anti-inflammatory and chemoprotective effects of 5-ASA treatment.
Age-related organ and tissue-specific cell kinetic and morphological alterations are associated with the incidence of numerous diseases in old age. Salivary dysfunction frequently appears in a wide range of older people and thus is a physiological and biological aspect of aging. The transcription factor Dec1 (differentiated embryo chondrocyte expressed gene 1) is essential for the regulation of cellular senescence. Here, we explored the morphological and physiological abnormalities and the microRNA (miRNA) expression profiles in the submandibular glands (SMGs) of young (3-month-old) and of aged (24-month-old) wild-type (WT) and Dec1KO mice. Hematoxylin-eosin (H-E) staining, Masson’s Trichrome staining, immunohistochemistry, immunofluorescence, and quantitative real time PCR were employed. MicroRNA (miRNA) expression profiles were examined using an Agilent system with a Mouse 8x60K array. Immunohistochemical analysis revealed an increased oxidative stress response (8-OHdG), increased expression levels of type I collagen in the fibrotic tissues with substantial amounts of fibroblasts and collagen fibers, the presence of CCl-22-positive lymphocytes infiltrating the SMGs of aged WT mice and a subsequently enhanced expression of fibrosis-associated gene (MMP-2) in the aged SMGs. The water channel protein aquaporin-5 (AQP5) was expressed in the basal cytoplasmic regions of acini in young SMGs but showed a decreased expression in aged SMGs. Myoepithelial cell markers (p63 immunoreactivity and α-SMA immunofluorescence staining) were also decreased in aged SMGs. Quantitative real-time PCR revealed decreased mRNA expression levels of AQP5 and increased mRNA expression levels of Dec1 in aged WT mice. All those characteristics were attenuated in aged Dec1KO mice. There were no apparent differences between young WT and Dec1KO mice. Of the miRNAs analyzed, miR-181c-5p, miR-141-3p, miR-374c-5p and miR-466i-3p are proposed regulatory targets of Dec1 and AQP5 genes that are involved in SMG dysfunction in aged mice. We suggest that a Dec1 deficiency might alleviate the aging-induced hypofunction of SMGs and relevant alterations of Dec1 would be useful to keep SMGs healthy. This study provides clues for determining unique microRNAs concerned with SMG dysfunction. Subsequent activation of such diversely expressed miRNAs be of great value in clarifying the nature of age-related alterations in SMGs.
Curcumin has been testified to repress the development of multiple tumor cells. Nevertheless, the function of curcumin in colorectal cancer (CRC) is not completely clarified. This research was to explore the influence of curcumin on the development of CRC cells and its mechanism. An examination of circular RNA (circ) HN1, microRNA (miR)-302a-3p and phosphoinositide-3-kinase regulatory subunit 3 (PIK3R3) levels in clinical tissues was performed. Assessments of cell development including proliferation, apoptosis, migration, invasion, as well as epithelial-mesenchymal transition were conducted. The effects of curcumin and circHN1 were verified by in vivo tumor implantation experiments. The interaction of miR-302a-3p with circHN1 or PIK3R3 was analyzed. Curcumin repressed CRC cell development in a concentration-dependent manner. CircHN1 expression was augmented in CRC. Augmentation of circHN1 was able to turn around the repressive effects of curcumin on CRC cells. In vivo experiments indicated that low expression of circHN1 further promoted curcumin-mediated inhibition of CRC tumor growth. MiR-302a-3p was a target of circHN1, and suppression of miR-302a-3p was able to turn around the treatment effect of curcumin on CRC cells. Additionally, PIK3R3 was targeted by miR-302a-3p, and curcumin modulated the malignancy of CRC cells through the circHN1/miR-302a-3p/PIK3R3 pathway.
Long non-coding RNAs (lncRNAs) are series of transcripts with important biological functions. Various diseases have been associated with aberrant expression of lncRNAs and the related dysregulation of mRNAs. In this review, we highlight the mechanisms of dynamic lncRNA expression. The chromatin state contributes to the low and specific expression of lncRNAs. The transcription of non-coding RNA genes is regulated by many core transcription factors applied to protein-coding genes. However, specific DNA sequences may allow their unsynchronized transcription with their location-associated mRNAs. Additionally, there are multiple mechanisms involved in the post-transcriptional regulation of lncRNAs. Among these, microRNAs might have indispensible regulatory effects on lncRNAs, based on recent discoveries.
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