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Background/Objectives: KRT23 was recently discovered as an epithelial-specific intermediate filament protein in the type I keratin family. Many studies have underlined keratin's involvement in several biological processes as well as in the pathogenesis of different diseases. Specifically, KRT23 was reported to affect the structural integrity of epithelial cells and to trigger cellular signaling leading to the onset of cancer. The aim of this study is to characterize a novel mechanism based on miR-195-5p/KRT23 in colorectal cancer. Methods: KRT23 mRNA and protein expression were characterized in FFPE sections from patients with CRC. The effects of miR-195-5p on KRT23 expression at the mRNA and protein levels were assessed by transient transfection experiments with mimic and inhibitor molecules. Cell attachment/detachment, migration, invasion, clone formation, and apoptosis were evaluated in human CRC cell lines after miR-195-5p mimic transfection. Results: We identified KRT23 as a putative target of miR-195-5p, a microRNA that we previously demonstrated to be reduced in CRC. We have proved the KRT23 expression deregulation in the tumoral section compared to adjacent normal mucosa in patients with CRC, according to the data derived from the public repository. We proved that the gain of miR-195-5p decreased the KRT23 expression. Conversely, we demonstrated that the inhibition of miR-195-5p led to an increase in KRT23 expression levels. We have demonstrated the in vitro effectiveness of miR-195-5p on CRC progression and that the in vivo intraperitoneal delivery of miR-195-5p mimic lowered colonic KRT23 mRNA and protein expression. Conclusions: These findings highlight a new regulatory mechanism by miR-195-5p in CRC affecting the keratin intermediate filaments and underline the miR-195-5p potential clinical properties. [ABSTRACT FROM AUTHOR]

Desmosomes play a key role in the regulation of cell adhesion and signaling. Dysregulation of the desmosome complex is associated with the loss of epithelial cell polarity and disorganized tissue architecture typical of colorectal cancer (CRC). The aim of this study was to investigate and characterize the effect of miR-195-5p on desmosomal junction regulation in CRC. In detail, we proposed to investigate the deregulation of miR-195-5p and JUP, a gene target that encodes a desmosome component in CRC patients. JUP closely interacts with desmosomal cadherins, and downstream, it regulates several intracellular transduction factors. We restored the miR-195-5p levels by transient transfection in colonic epithelial cells to examine the effects of miR-195-5p on JUP mRNA and protein expression. The JUP regulation by miR-195-5p, in turn, determined a modulation of desmosome cadherins (Desmoglein 2 and Desmocollin 2). Furthermore, we focused on whether the miR-195-5p gain of function was also able to modulate the expression of key components of Wnt signaling, such as NLK, LEF1 and Cyclin D1. In conclusion, we have identified a novel mechanism controlled by miR-195-5p in the regulation of adhesive junctions, suggesting its potential clinical relevance for future miRNA-based therapy in CRC. [ABSTRACT FROM AUTHOR]

Inflammasomes are multiprotein complexes expressed by immune cells in response to distinct stimuli that trigger inflammatory responses and the release of pro-inflammatory cytokines. Evidence suggests a different role of inflammasome NLRP3 in IBD. NLRP3 inflammasome activation can be controlled by post-translational modifications such as ubiquitination through BRCC3. The aim of this study was to investigate the effect of miR-369-3p on the expression and activation of NLRP3 inflammasomes via BRCC3 regulation. After bioinformatics prediction of Brcc3 as a gene target of miR-369-3p, in vitro, we validated its modulation in bone marrow-derived macrophages (BMDM). The increase in miR-369-3p significantly reduced BRCC3 gene and protein expression. This modulation, in turn, reduced the expression of NLRP3 and blocked the recruitment of ASC adaptor protein by NLRP3. As a result, miR-369-3p reduced the activity of Caspase-1 by the inflammasome, decreasing the cleavage of pro-IL-1β and pro-IL-18. These results support a novel mechanism that seems to act on post-translational modification of NLRP3 inflammasome activation by BRCC3. This may be an interesting new target in the personalized treatment of inflammatory disorders, including IBD. [ABSTRACT FROM AUTHOR]

The immunoproteasome is a multi-catalytic protein complex expressed in hematopoietic cells. Increased expression of immuno-subunits followed by increased proteasome activities is associated with the pathogenesis of IBD. Therefore, the identification of molecules that could inhibit the activities of this complex has been widely studied. microRNAs are small molecules of non-coding RNA that regulate the expression of target genes. Our purpose was to demonstrate that miR-369-3p is able to reduce the expression of the PSMB9 subunit and consequently modulate the catalytic activities of immunoproteasome. After bioinformatics prediction of the gene target of miR-369-3p, we validated its modulation on PSMB9 expression in the RAW264.7 cell line in vitro. We also found that miR-369-3p indirectly reduced the expression of other immunoproteasome subunits and that this regulation reduced the catalytic functions of the immunoproteasome. Increased levels of PSMB9 were observed in colon samples of acute IBD patients compared to the remission IBD group and control group. Our data suggest that miR-369-3p may be a future alternative therapeutic approach to several compounds currently used for the treatment of inflammatory disorders including IBD. [ABSTRACT FROM AUTHOR]