miR-369-3p Modulates Intestinal Inflammatory Response via BRCC3/NLRP3 Inflammasome Axis

Anti-Inflammatory Effects of miR-369-3p via PDE4B in Intestinal Inflammatory Response

Cyclic nucleotide phosphodiesterases (PDEs) consist of a family of enzymes expressed in several types of cells, including inflammatory cells, that play a pivotal role in inflammation. Several studies have demonstrated that the inhibition of PDE4 results in a reduced inflammatory response via PKA and CREB signaling. Hence, PDE4 suppression improves the inflammatory feedback typical of several diseases, such as inflammatory bowel disease (IBD). In our previous studies, we have demonstrated that miR-369-3p regulates inflammatory responses, modulating different aspects of the inflammatory process. The aim of this study was to demonstrate an additional anti-inflammatory effect of miR-369-3p targeting PDE4B, one of the widely expressed isoforms in immune cells. We found that miR-369-3p was able to reduce the expression of PDE4B, elevating the intracellular levels of cAMP. This accumulation increased the expression of PKA and pCREB, mitigating the release of pro-inflammatory cytokines and promoting the release of anti-inflammatory cytokines. To prove that PDE4B is a good therapeutic target in IBD, we also demonstrate that the expression of PDE4B was increased in UC patients compared to healthy controls, affecting the immune infiltrate. PDE4B is considered an important player in inflammatory progression; hence, our results show the ability of miR-369-3p to ameliorate inflammation by targeting PDE4B, supporting its future application as a new therapeutic approach in IBD.

NLRP3 inflammasome and its role in autoimmune diseases: A promising therapeutic target

The NOD-like receptor protein 3 (NLRP3) inflammasome is a protein complex that regulates innate immune responses by activating caspase-1 and the inflammatory cytokines IL-1β and IL-18. Numerous studies have highlighted its crucial role in the pathogenesis and development of inflammatory bowel disease, rheumatoid arthritis, systemic lupus erythematosus, autoimmune thyroid diseases, and other autoimmune diseases. Therefore, investigating the underlying mechanisms of NLRP3 in disease and targeted drug therapies holds clinical significance. This review summarizes the structure, assembly, and activation mechanisms of the NLRP3 inflammasome, focusing on its role and involvement in various autoimmune diseases. This review also identifies studies where the involvement of the NLRP3 inflammasome in the disease mechanism within the same disease appears contradictory, as well as differences in NLRP3-related gene polymorphisms among different ethnic groups. Additionally, the latest therapeutic advances in targeting the NLRP3 inflammasome for autoimmune diseases are outlined, and novel clinical perspectives are discussed. Conclusively, this review provides a consolidated source of information on the NLRP3 inflammasome and may guide future research efforts that have the potential to positively impact patient outcomes.

Identification of a Novel miR-195-5p/PNN Axis in Colorectal Cancer

Pinin (PNN) is a desmosome-associated protein that reinforces the organization of keratin intermediate filaments and stabilizes the anchoring of the cytoskeleton network to the lateral surface of the plasma membrane. The aberrant expression of PNN affects the strength of cell adhesion as well as modifies the intracellular signal transduction pathways leading to the onset of CRC. In our previous studies, we characterized the role of miR-195-5p in the regulation of desmosome junctions and in CRC progression. Here, with the aim of investigating additional mechanisms related to the desmosome complex, we identified PNN as a miR-195-5p putative target. Using a public data repository, we found that PNN was a negative prognostic factor and was overexpressed in colon cancer tissues from stage 1 of the disease. Then, we assessed PNN expression in CRC tissue specimens, confirming the overexpression of PNN in tumor sections. The increase in intracellular levels of miR-195-5p revealed a significant decrease in PNN at the mRNA and protein levels. As a consequence of PNN regulation by miR-195-5p, the expression of KRT8 and KRT19, closely connected to PNN, was affected. Finally, we investigated the in vivo effect of miR-195-5p on PNN expression in the colon of AOM/DSS-treated mice. In conclusion, we have revealed a new mechanism driven by miR-195-5p in the regulation of desmosome components, suggesting a potential pharmacological target for CRC therapy.

miR-195-5p as Regulator of γ-Catenin and Desmosome Junctions in Colorectal Cancer

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.

Early-Onset Neonatal Sepsis: Inflammatory Biomarkers and MicroRNA as Potential Diagnostic Tools in Preterm Newborns

Mortality and morbidity of newborns with sepsis can be improved by early and accurate diagnosis and targeted therapy. To evaluate the early molecular events associated with inflammation and infection, we evaluated markers of endothelial activation and injury and circulating plasma miRNAs in preterm newborns with sepsis. The study group consisted of newborns with gestational age ≤ 32 weeks, with culture-positive early-onset neonatal sepsis (sepsis group, N = 8), and as a control group, we enrolled newborns without sepsis (control group, N = 12). Soluble markers of inflammation were measured using Luminex-based multiplex assay. Platelet-free plasma RNA was used to construct the library for miRNA sequencing analysis. Normalized counts were calculated and used to measure differential expression of individual detected miRNAs. We found a significant increase of interleukin 18 (IL-18) in the cord blood of the sepsis group (mean ± SEM, 104.7 ± 30.4 pg/ml vs 52.7 ± 5.6 pg/ml, P = 0.02). In peripheral blood of sepsis group patients, we found a significant increase of VEGF-A compared to controls (196.0 ± 70.5 pg/ml vs 59.6 ± 8.5 pg/ml, P = 0.02). In the cord blood plasma, eight miRNAs had significantly differential expression (P < 0.05), four miRNAs were up-regulated and four miRNAs down-regulated. In peripheral blood plasma, all nine miRNAs with significant differential expression were up-regulated. In conclusion, in early-onset neonatal sepsis, IL-18 and VEGF-A might be considered in diagnostic workup. Early-onset sepsis in preterm newborns is associated with significant changes in the circulating miRNA pattern.