Association of miRNA-146a rs2910164 and miRNA-196 rs11614913 polymorphisms in patients with ulcerative colitis: A meta-analysis and review

Hsa_circ_0004662 Accelerates the Progression of Ulcerative Colitis via the microRNA-532/HMGB3 Signalling Axis

Increasing research has indicated that circular RNAs (circRNAs) are crucial for the development of ulcerative colitis (UC). Thus, we attempted to identify the role of hsa_circ_0004662 in UC progression. Hsa_circ_0004662 expression was determined via qRT-PCR. Lipopolysaccharide (LPS)-induced inflammation in normal colonic epithelial cells (ECs). The hsa_circ_0004662 content was then assessed in a mucosal inflammatory bowel disease (IBD) model. Cell proliferation was examined via CCK-8 and EdU uptake assays. Apoptotic rates were analysed via flow cytometry. The protein content was quantified via Western blotting. Enzyme-linked immunosorbent assay kits were used to detect IL-1β, TNF-α and IL-6, and dual-luciferase reporter (DLR) assays were used to identify interactions between miR-532 and circ_0004662 or HMGB3. An animal model of UC was also developed for confirmation. In this study, we identified the function of hsa_circ_0004662 in promoting UC progression. Hsa_circ_0004662 was upregulated in clinical UC tissues and LPS-induced colonic ECs, and its knockdown inhibited apoptosis, reduced inflammatory cytokine release and promoted cell proliferation in vitro. Mechanistically, hsa_circ_0004662 acted as a molecular sponge for miR-532, which targets HMGB3. The hsa_circ_0004662/miR-532/HMGB3 axis was further validated in a DSS-induced colitis mouse model, where hsa_circ_0004662 knockdown attenuated inflammation and tissue damage. These findings suggested that hsa_circ_0004662 contributes to UC progression through the miR-532/HMGB3 signalling pathway, offering potential targets for UC therapy.

Oral Delivery of miR146a Conjugated to Cerium Oxide Nanoparticles Improves an Established T Cell-Mediated Experimental Colitis in Mice

Background: Dysregulated inflammation and oxidative stress are strongly implicated in the pathogenesis of inflammatory bowel disease. We have developed a novel therapeutic that targets inflammation and oxidative stress. It is comprised of microRNA-146a (miR146a)-loaded cerium oxide nanoparticles (CNPs) (CNP-miR146a). We hypothesized that oral delivery of CNP-miR146a would reduce colonic inflammation in a mouse model of established, chronic, T cell-mediated colitis. Methods: The stability of CNP-miR146a and mucosal delivery was assessed in vitro with simulated gastrointestinal fluid and in vivo after oral gavage by quantitative real-time RT-PCR. The efficacy of orally administered CNP-miR146a was tested in mice with established colitis using the model of adoptive naïve T-cell transfer in recombinant activating gene 2 knockout (Rag2-/-) mice. Measured outcomes included histopathology; CD45+ immune cell infiltration; oxidative DNA damage (tissue 8-hydroxy-2'-deoxyguanosine; 8-OHdG); expression of IL-6 and TNF mRNA and protein, and flow cytometry analysis of lamina propria Th1 and Th17 cell populations. Results: miR146a expression remained stable in simulated gastric and intestinal conditions. miR146a expression increased in the intestines of mice six hours following oral gavage of CNP-miR146a. Oral delivery of CNP-miR146a in mice with colitis was associated with reduced inflammation and oxidative stress in the proximal and distal colons as evidenced by histopathology scoring, reduced immune cell infiltration, reduced IL-6 and TNF expression, and decreased populations of CD4+Tbet+IFNg+ Th1, CD4+RorgT+IL17+ Th17, as well as pathogenic double positive IFNg+IL17+ T cells. Conclusions: CNP-miR146a represents a novel orally available therapeutic with high potential to advance into clinical trials.

Protective role of circRNA CCND1 in ulcerative colitis via miR-142-5p/NCOA3 axis

BACKGROUND

Increasing research indicates that circular RNAs (circRNAs) play critical roles in the development of ulcerative colitis (UC). This study aimed to determine the role of circRNA CCND1 in UC bio-progression, which has been shown to be downregulated in UC tissues.

METHODS

Reverse transcription quantitative polymerase chain reaction was used to determine the levels of circRNA CCND1, miR-142-5p, and nuclear receptor coactivator-3 (NCOA3) in UC tissues and in lipopolysaccharide (LPS)-induced Caco-2 cells. Target sites of circRNA CCND1 and miR-142-5p were predicted using StarBase, and TargetScan to forecast potential linkage points of NCOA3 and miR-142-5p, which were confirmed by a double luciferase reporter-gene assay. Cell Counting Kit 8 and flow cytometry assays were performed to assess Caco-2 cell viability and apoptosis. TNF-α, IL-1β, IL-6, and IL-8 were detected using Enzyme-Linked Immunosorbent Assay kits.

RESULTS

CircRNA CCND1 was downregulated in UC clinical samples and LPS-induced Caco-2 cells. In addition, circRNA CCND1 overexpression suppressed LPS-induced apoptosis and inflammatory responses in Caco-2 cells. Dual-luciferase reporter-gene assays showed that miR-142-5p could be linked to circRNA CCND1. Moreover, miR-142-5p was found to be highly expressed in UC, and its silencing inhibited LPS-stimulated Caco-2 cell apoptosis and inflammatory responses. Importantly, NCOA3 was found downstream of miR-142-5p. Overexpression of miR-142-5p reversed the inhibitory effect of circRNA CCND1-plasmid on LPS-stimulated Caco-2 cells, and the effects of miR-142-5p inhibitor were reversed by si-NCOA3.

CONCLUSION

CircRNA CCND1 is involved in UC development by dampening miR-142-5p function, and may represent a novel approach for treating UC patients.

Polymorphisms of miR-146a and susceptibility to ulcerative colitis risk: a case-control study

Considering the role of miR-146a in the control of inflammation, we assessed the importance of two miR-146a polymorphisms (rs2910164 and rs57095329) in the development and severity of ulcerative colitis (UC) in Iran. Genomic DNA of 150 cases with UC and 200 healthy individuals were genotyped using the PCR-RFLP technique. Statistical analyses were performed using Med Calc software. The miR-146a rs2910164 C allele was significantly associated with increased risk of UC. Individuals carrying the CC (rs2910164) were more than fourfold higher risk of UC relative to wild type homozygotes. The combined GC + CC genotypes were also associated with increased UC risk. We also found that the rs2910164 CC genotype was associated with a severe form of the disease However, the distribution of variant allele and genotypes of rs57095329 did not differ between the cases and controls. In conclusion, miR-146a rs2910164 polymorphism may play a role in UC. To confirm our findings, additional well-designed studies in diverse ethnic populations are required.

KT2 alleviates ulcerative colitis by reducing Th17 cell differentiation through the miR-302c-5p/STAT3 axis

BACKGROUND

The abnormal differentiation of Th17 cells aggravates ulcerative colitis (UC). Antimicrobial peptides (AMPs) exert pivotal protection functions against UC. KT2 is a cationic AMP that mediates colon cancer development. However, KT2's function in UC remains unclear.

METHODS

The UC mouse model was induced by administering 2.5% dextran sulfate sodium, and the mice were given an enema of KT2. KT2's function in UC and Th17 cell differentiation in vivo was evaluated through various molecular experiments. The KT2's function in Th17 cell differentiation in vitro was evaluated by the proportion of CD4⁺ IL-17⁺ T cells, IL-17 levels, and RORγt expression levels. Meanwhile, the mechanism was assessed through quantitative real-time PCR, various loss-of-function assays, and dual-luciferase reporter gene assay.

RESULTS

KT2 restrained Th17 cell differentiation in both in vivo and in vitro UC models and slowed the UC process. KT2 elevated miR-302c-5p expression, as well as restrained Th17 cell differentiation by increasing miR-302c-5p. Meanwhile, miR-302c-5p interacted with the signal transducer and activator of transcription 3 (STAT3) and negatively regulated its expression. Furthermore, our data revealed that KT2 restrained the activation of STAT3 by elevating miR-302c-5p, thereby inhibiting Th17 cell differentiation.

CONCLUSION

KT2 alleviates UC by repressing Th17 cell differentiation through the miR-302c-5p/STAT3 axis.

Fas and microRNAs Variations as a Possible Risk for Behçet Disease

BACKGROUND

Behçet disease (BD) belongs to a disease family that has a transparent borderline between autoinflammatory and autoimmune disorders. Fas and some miRNAs have revealed to display remarkable roles in both autoimmune and autoinflammatory processes, and they can play important roles in defective apoptosis in BD. We investigated the association of the susceptibility of BD with Fas, miRNA variations, and their both single and combined presence in a Turkish population as a case-control study.

METHODS

The distributions of FAS-670 A>G rs1800682, mir146a rs2910164, and mir196a rs11614913 polymorphisms are analyzed with the polymerase chain reaction-restriction fragment length polymorphism method in 115 BD patients and 220 controls in 6-month period.

RESULTS

Statistical analysis indicates that in the case of Fas-670 A/G rs1800682, AA genotype and A allele have a protective role in BD (p = 0.0004 and p = 0.0009, respectively). The dominant model (AA + AG/GG) also displays a protective effect on BD unlike the recessive model (p = 0.03). In addition, both homozygous genotype (CC) of rs2910164 of mir-146a (p = 0.04) and the dominant model (CC + CG vs. GG) have protective effects on BD unlike the recessive model (p < 0.0001). Both mir-196a2 rs1800682 polymorphism and combined genotype analysis of rs1800682-rs2910164 and rs1800682-rs11614913 gave no statistically significant differences within the groups for genotypes and either of the alleles (p > 0.05).

CONCLUSIONS

These findings indicate that both Fas rs1800682 and mir-146a rs2910164 variants might be important factors participating in the protection against BD in the Turkish population.

Critical roles of microRNA-196 in normal physiology and non-malignant diseases: Diagnostic and therapeutic implications

MicroRNAs (miRNAs) have emerged as a critical component of regulatory networks that modulate and fine-tune gene expression in a post-transcriptional manner. The microRNA-196 family is encoded by three loci in the human genome, namely hsa-mir-196a-1, hsa-mir-196a-2, and hsa-mir-196b. Increasing evidence supports the roles of different components of this miRNA family in regulating key cellular processes during differentiation and development, ranging from inflammation and differentiation of stem cells to limb development and remodeling and structure of adipose tissue. This review first discusses about the genomic context and regulation of this miRNA family and then take a bird's eye view on the updated list of its target genes and their biological processes to obtain insights about various functions played by members of the microRNA-196 family. We then describe evidence supporting the involvement of the human microRNA-196 family in regulating critical cellular processes both in physiological and non-malignant inflammatory conditions, highlighting recent seminal findings that carry implications for developing novel therapeutic or diagnostic strategies.

The role of the miR-21-5p-mediated inflammatory pathway in ulcerative colitis

Ulcerative colitis (UC), a major type of inflammatory bowel disease, is also a chronic non-specific intestinal inflammation condition of unknown etiology. The pathogenesis of UC is closely associated with immune abnormalities, inflammatory damage and genetics. The present study aimed to explore the effects of microRNA (miR)-21-5p on the interleukin-6 (IL-6) receptor (IL6R)/signal transducer and activator of transcription (STAT3) signal pathway in UC, in order to identify a highly effective treatment for UC. A total of 45 patients with UC and 45 healthy controls were recruited for the present study. The expression levels of miR-21-5p and STAT3 in the sera of patients with UC and healthy controls were determined by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). A UC rat model was established using dextran sulfate sodium. Following lipopolysaccharide (LPS) treatment, RAW264.7 cells were transfected with a miR-21-5p inhibitor. The levels of morphological damage and apoptosis of the colonic mucosal epithelial tissue were investigated using hematoxylin and eosin staining and a TUNEL staining assay, and then the colon macroscopic damage index and disease activity index were measured in rats. Western blot analysis was used to detect the protein expression levels of IL6R, STAT3, intracellular adhesion molecule 1 (ICAM-1), NF-κB, cleaved caspase-3, cleaved caspase-9 and Fas ligand (FasL). RT-qPCR detected the mRNA expression levels of miR-21-5p, IL6R, STAT3, ICAM-1, NF-κB, caspase-3, caspase-9 and FasL. An ELISA was performed to measure the levels of inflammatory cytokines. The viability and apoptosis levels of RAW264.7 cells were examined using MTT and flow cytometry assays. Additionally, STAT3 was investigated as a direct target of miR-21-5p in RAW264.7 cells using a dual-luciferase reporter assay. The results of the present study demonstrated that inflammation and apoptotic markers were revealed to be significantly downregulated following transfection with miR-21-5p inhibitors in RAW264.7 cells induced by LPS, and that cell viability was increased. Furthermore, STAT3 was confirmed to be a target of miR-21-5p in RAW264.7 cells. Collectively, these data demonstrated that miR-21-5p inhibition mediated the IL-6/STAT3 pathway in UC rats to decrease the levels of inflammation and apoptosis in RAW264.7 cells, and suggested that miR-21-5p may be an important therapy target in human UC.