Roles of microRNAs in inflammatory bowel disease

Peroxiredoxin 3 deficiency exacerbates DSS-induced acute colitis via exosomal miR-1260b-mediated barrier disruption and pro-inflammatory signaling

AIMS

Peroxiredoxin3 (Prdx3) is an intracellular antioxidant enzyme that is specifically localized in mitochondria and protects against oxidative stress by removing mitochondrial reactive oxygen species (ROS). The intestinal epithelium provides a physical and biochemical barrier that segregates host tissues from commensal bacteria to maintain intestinal homeostasis. An imbalance between the cellular antioxidant defense system and oxidative stress has been implicated in the pathogenesis of inflammatory bowel disease (IBD). However, the role of Prdx3 in the intestinal epithelium under intestinal inflammation has not been elucidated. To investigate the potential role of Prdx3 in intestinal inflammation, we used intestinal epithelial cell (IEC)-specific Prdx3-knockout mice.

RESULTS

IEC-specific Prdx3-deficient mice showed more severe colitis phenotypes with greater degrees of body weight loss, colon shortening, barrier disruption, mitochondrial damage, and ROS generation in IECs. Furthermore, exosomal miR-1260b was dramatically increased in Prdx3-knockdown colonic epithelial cells. Mechanistically, Prdx3 deficiency promoted intestinal barrier disruption and inflammation via P38-MAPK/NFκB signaling.

INNOVATION

this is the first study to report the protective role of Prdx3 in acute colitis using IEC-specific conditional knockout mice.

CONCLUSION

our study sheds light on the role of exosome-loaded miRNAs, particularly miR-1260b, in IBD. targeting miR-1260b or modulating exosome-mediated intercellular communication may hold promise as potential therapeutic strategies for managing IBD and restoring intestinal barrier integrity.

Long non-coding RNAs as pathophysiological regulators, therapeutic targets and novel extracellular vesicle biomarkers for the diagnosis of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic relapsing disease of the gastrointestinal (GI) system that includes two groups, Crohn's disease (CD) and ulcerative colitis (UC). To cope with these two classes of IBD, the investigation of pathogenic mechanisms and the discovery of new diagnostic and therapeutic approaches are crucial. Long non-coding RNAs (lncRNAs) which are non-coding RNAs with a length of longer than 200 nucleotides have indicated significant association with the pathology of IBD and strong potential to be used as accurate biomarkers in diagnosing and predicting responses to the IBD treatment. In the current review, we aim to investigate the role of lncRNAs in the pathology and development of IBD. We first describe recent advances in research on dysregulated lncRNAs in the pathogenesis of IBD from the perspective of epithelial barrier function, intestinal immunity, mitochondrial function, and intestinal autophagy. Then, we highlight the possible translational role of lncRNAs as therapeutic targets, diagnostic biomarkers, and predictors of therapeutic response in colon tissues and plasma samples. Finally, we discuss the potential of extracellular vesicles and their lncRNA cargo in the pathophysiology, diagnosis, and treatment of IBD.

Animal models of inflammatory bowel disease: category and evaluation indexes

Inflammatory bowel disease (IBD) research often relies on animal models to study the etiology, pathophysiology, and management of IBD. Among these models, rats and mice are frequently employed due to their practicality and genetic manipulability. However, for studies aiming to closely mimic human pathology, non-human primates such as monkeys and dogs offer valuable physiological parallels. Guinea pigs, while less commonly used, present unique advantages for investigating the intricate interplay between neurological and immunological factors in IBD. Additionally, New Zealand rabbits excel in endoscopic biopsy techniques, providing insights into mucosal inflammation and healing processes. Pigs, with their physiological similarities to humans, serve as ideal models for exploring the complex relationships between nutrition, metabolism, and immunity in IBD. Beyond mammals, non-mammalian organisms including zebrafish, Drosophila melanogaster, and nematodes offer specialized insights into specific aspects of IBD pathology, highlighting the diverse array of model systems available for advancing our understanding of this multifaceted disease. In this review, we conduct a thorough analysis of various animal models employed in IBD research, detailing their applications and essential experimental parameters. These include clinical observation, Disease Activity Index score, pathological assessment, intestinal barrier integrity, fibrosis, inflammatory markers, intestinal microbiome, and other critical parameters that are crucial for evaluating modeling success and drug efficacy in experimental mammalian studies. Overall, this review will serve as a valuable resource for researchers in the field of IBD, offering insights into the diverse array of animal models available and their respective applications in studying IBD.

Predictive biomarkers for anti-TNF alpha therapy in IBD patients

Inflammatory bowel disease (IBD) is a chronic gastrointestinal condition characterized by severe gut inflammation, commonly presenting as Crohn's disease, ulcerative colitis or categorized as IBD- unclassified. While various treatments have demonstrated efficacy in adult IBD patients, the advent of anti-TNF therapies has significantly revolutionized treatment outcomes and clinical management. These therapies have played a pivotal role in achieving clinical and endoscopic remission, promoting mucosal healing, averting disease progression, and diminishing the necessity for surgery. Nevertheless, not all patients exhibit positive responses to these therapies, and some may experience a loss of responsiveness over time. This review aims to present a comprehensive examination of predictive biomarkers for monitoring the therapeutic response to anti-TNF therapy in IBD patients. It will explore their limitations and clinical utilities, paving the way for a more personalized and effective therapeutic approach.

Recent Trends in Non-Invasive Methods of Diagnosis and Evaluation of Inflammatory Bowel Disease: A Short Review

Inflammatory bowel diseases are a conglomerate of disorders causing inflammation of the gastrointestinal tract, which have gained a significant increase in prevalence in the 21st century. As they present a challenge in the terms of diagnosis as well as treatment, IBDs can present an overwhelming impact on the individual and can take a toll on healthcare costs. Thus, a quick and precise diagnosis is required in order to prevent the high number of complications that can arise from a late diagnosis as well as a misdiagnosis. Although endoscopy remains the primary method of evaluation for IBD, recent trends have highlighted various non-invasive methods of diagnosis as well as reevaluating previous ones. This review focused on the current non-invasive methods in the diagnosis of IBD, exploring their possible implementation in the near future, with the goal of achieving earlier, feasible, and cheap methods of diagnosis as well as prognosis in IBD.

MicroRNA and granulocyte-monocyte adsorption apheresis combotherapy after inadequate response to anti-TNF agents in ulcerative colitis

BACKGROUND

Ulcerative colitis (UC) is an inflammatory bowel disease characterized by chronic inflammation of the gastrointestinal tract, affecting millions of individuals throughout the world, and producing an impaired health-related quality of life. Granulocyte and monocyte apheresis (GMA) is a therapeutic option for UC management to induce remission by selective removal of activated leukocytes from bloodstream. Despite the knowledge of the important role of epigenetics in UC pathogenesis, and in the response to different treatments, nothing is known about the role of microRNAs in GMA therapy in UC patients.

METHODS

Seven consecutively UC patients who started GMA in combo therapy with infliximab were recruited. Peripheral blood samples were taken before the apheresis session, at the start of the induction (S0) and at the end (S10). They were follow-up during the induction phase (10 sessions: 2 sessions for a week during 3 wk and 1 session for a week during 4 wk) of the treatment at a tertiary hospital (Hospital la Fe) and 6 mo after finishing the GMA induction therapy. MiRNA was extracted and analyzed by RT-PCR. R software and GraphPad were used.

RESULTS

Clinical disease activity significantly decreased after induction therapy with GMA (median partial Mayo score 2 (IQR, 1-6) (P < .05). Fecal calprotectin value and CRP value significantly decreased after induction therapy. Five microRNAs modified their expression during GMA (unsupervised analysis): miR-342-3p, miR-215-5p, miR-376c-3p, miR-139-5p, and miR-150-5p. When a sub-analysis was performed in those patients who showed good response to apheresis treatment (n = 5), two microRNAs showed to be implicated: miR-215-5p and miR-365a-3p. These are preliminary but promising and novel results, as it is the first time, to our knowledge that microRNA profiles have been studied in the context of GMA treatment for IBD.

Circular RNA Cdr1as inhibits proliferation and delays injury-induced regeneration of the intestinal epithelium

Circular RNAs (circRNAs) are highly expressed in the mammalian intestinal epithelium, but their functions remain largely unknown. Here, we identified the circRNA Cdr1as as a repressor of intestinal epithelial regeneration and defense. Cdr1as levels increased in mouse intestinal mucosa after colitis and septic stress, as well as in human intestinal mucosa from patients with inflammatory bowel disease and sepsis. Ablation of the Cdr1as locus from the mouse genome enhanced renewal of the intestinal mucosa, promoted injury-induced epithelial regeneration, and protected the mucosa against colitis. We found approximately 40 microRNAs, including miR-195, differentially expressed between intestinal mucosa of Cdr1as-knockout (Cdr1as-/-) versus littermate mice. Increasing the levels of Cdr1as inhibited intestinal epithelial repair after wounding in cultured cells and repressed growth of intestinal organoids cultured ex vivo, but this inhibition was abolished by miR-195 silencing. The reduction in miR-195 levels in the Cdr1as-/- intestinal epithelium was the result of reduced stability and processing of the precursor miR-195. These findings indicate that Cdr1as reduces proliferation and repair of the intestinal epithelium at least in part via interaction with miR-195 and highlight a role for induced Cdr1as in the pathogenesis of unhealed wounds and disrupted renewal of the intestinal mucosa.

miR-195b is required for proper cellular homeostasis in the elderly

Over the last decade we have witnessed an increasing number of studies revealing the functional role of non-coding RNAs in a multitude of biological processes, including cellular homeostasis, proliferation and differentiation. Impaired expression of non-coding RNAs can cause distinct pathological conditions, including herein those affecting the gastrointestinal and cardiorespiratory systems, respectively. miR-15/miR-16/miR-195 family members have been broadly implicated in multiple biological processes, including regulation of cell proliferation, apoptosis and metabolism within distinct tissues, such as heart, liver and lungs. While the functional contribution of miR-195a has been reported in multiple biological contexts, the role of miR-195b remains unexplored. In this study we dissected the functional role of miR-195b by generating CRISPR-Cas9 gene edited miR-195b deficient mice. Our results demonstrate that miR-195b is dispensable for embryonic development. miR-195b-/- mice are fertile and displayed no gross anatomical and/or morphological defects. Mechanistically, cell cycle regulation, metabolism and oxidative stress markers are distinctly impaired in the heart, liver and lungs of aged mice, a condition that is not overtly observed at midlife. The lack of overt functional disarray during embryonic development and early adulthood might be due to temporal and tissue-specific compensatory mechanisms driven by selective upregulation miR-15/miR-16/miR-195 family members. Overall, our data demonstrated that miR-195b is dispensable for embryonic development and adulthood but is required for cellular homeostasis in the elderly.

Differential expression of serum miR-486 and miR-25 in ulcerative colitis and Crohn's disease: Correlations with disease activity, extent, and location

Novel reliable biomarkers of inflammatory bowel disease (IBD) are clinically imperative due to potential limitations of endoscopic techniques. MicroRNAs (miRNAs) have emerged as non-invasive biomarkers of IBD; however, the full disease-specific miRNAs signature for IBD subtypes remains elusive. We evaluated the diagnostic role of circulating miR-486 and miR-25 in IBD patients and their potential ability to discriminate IBD subtypes; ulcerative colitis (UC) and Crohn's disease (CD). Sixty UC patients, 60 CD patients, and 60 healthy controls were recruited. Serum miRNA expression was determined using RT-qPCR. Bioinformatics was employed for target gene and protein-protein interaction (PPI) network analyses. Serum miR-486 was upregulated in CD patients, but didn't change in UC patients compared to controls. Conversely, serum miR-25 was decreased in both CD and UC patients compared to controls. Only miR-486 was differentially expressed between UC and CD patients. Receiver-operating characteristic analysis revealed that serum miR-486 was superior in CD diagnosis (AUC=0.945) and significantly distinguished CD and UC patients, whereas miR-25 showed discriminative potential for both UC and CD from controls. In the multivariate logistic analysis only miR-486 was associated with the risk of CD diagnosis. Serum miR-486 was correlated with CD activity index and location of disease in CD patients, whereas miR-25 was correlated with the type/extent of UC. PPI network analysis revealed common target genes and signaling pathways for both miRNAs. Conclusively, serum miR-486 and miR-25 might serve as new biomarkers of IBD, with serum miR-486 could be employed in risk stratification of IBD subtypes and has the ground for clinical utility in CD diagnosis, whereas miR-25 has potential for UC and CD diagnosis.

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

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.

miR-200a attenuated oxidative stress, inflammation, and apoptosis in dextran sulfate sodium-induced colitis through activation of Nrf2

Introduction

Oxidative stress and inflammatory responses are critical factors in ulcerative colitis disease pathogenesis. Nuclear factor erythroid 2-related factor 2 (Nrf2) modulates oxidative stress and suppresses inflammatory responses, and the protective benefits of Nrf2 activation have been associated with the therapy of ulcerative colitis. MicroRNA-200a (miR-200a) could target Kelch-like ECH-associated protein 1 (Keap1) and activate the Nrf2-regulated antioxidant pathway. Nevertheless, whether miR-200a modulates the Keap1/Nrf2 pathway in dextran sulfate sodium (DSS)-induced colonic damage is unknown. Here, our research intends to examine the impact of miR-200a in the model of DSS-induced colitis.

Methods

Prior to DSS intervention, we overexpressed miR-200a in mice for four weeks using an adeno-associated viral (AAV) vector to address this problem. ELISA detected the concentration of inflammation-related cytokines. The genes involved in inflammatory reactions and oxidative stress were identified using quantitative reverse transcription-polymerase chain reaction (qRT-PCR), western blot, and immunofluorescence. Moreover, we applied siRNAs to weakened Nrf2 expression to confirm the hypothesis that miR-200a provided protection via Nrf2.

Results

The present study discovered miR-200a down-regulation, excessive inflammatory activation, enterocyte apoptosis, colonic dysfunction, and Keap1/Nrf2 antioxidant pathway inactivation in mouse colitis and NCM460 cells under DSS induction. However, our data demonstrated that miR-200a overexpression represses Keap1 and activates the Nrf2 antioxidant pathway, thereby alleviating these adverse alterations in animal and cellular models. Significantly, following Nrf2 deficiency, we failed to observe the protective benefits of miR-200a against colonic damage.

Discussion

Taken together, through activating the Keap1/Nrf2 signaling pathway, miR-200a protected against DSS-induced colonic damage. These studies offer an innovative therapeutic approach for ulcerative colitis.

MicroRNA-based therapeutics for inflammatory disorders of the microbiota-gut-brain axis

An emerging but less explored shared pathophysiology across microbiota-gut-brain axis disorders is aberrant miRNA expression, which may represent novel therapeutic targets. miRNAs are small, endogenous non-coding RNAs that are important transcriptional repressors of gene expression. Most importantly, they regulate the integrity of the intestinal epithelial and blood-brain barriers and serve as an important communication channel between the gut microbiome and the host. A well-defined understanding of the mode of action, therapeutic strategies and delivery mechanisms of miRNAs is pivotal in translating the clinical applications of miRNA-based therapeutics. Accumulating evidence links disorders of the microbiota-gut-brain axis with a compromised gut-blood-brain-barrier, causing gut contents such as immune cells and microbiota to enter the bloodstream leading to low-grade systemic inflammation. This has the potential to affect all organs, including the brain, causing central inflammation and the development of neurodegenerative and neuropsychiatric diseases. In this review, we have examined in detail miRNA biogenesis, strategies for therapeutic application, delivery mechanisms, as well as their pathophysiology and clinical applications in inflammatory gut-brain disorders. The research data in this review was drawn from the following databases: PubMed, Google Scholar, and Clinicaltrials.gov. With increasing evidence of the pathophysiological importance for miRNAs in microbiota-gut-brain axis disorders, therapeutic targeting of cross-regulated miRNAs in these disorders displays potentially transformative and translational potential. Further preclinical research and human clinical trials are required to further advance this area of research.

Autophagy in intestinal fibrosis: relevance in inflammatory bowel disease

Chronic inflammation is often associated with fibrotic disorders in which an excessive deposition of extracellular matrix is a hallmark. Long-term fibrosis starts with tissue hypofunction and finally ends in organ failure. Intestinal fibrosis is not an exception, and it is a frequent complication of inflammatory bowel disease (IBD). Several studies have confirmed the link between deregulated autophagy and fibrosis and the presence of common prognostic markers; indeed, both up- and downregulation of autophagy are presumed to be implicated in the progression of fibrosis. A better knowledge of the role of autophagy in fibrosis may lead to it becoming a potential target of antifibrotic therapy. In this review we explore novel advances in the field that highlight the relevance of autophagy in fibrosis, and give special focus to fibrosis in IBD patients.

Pharmacogenetic Analysis of the MIR146A rs2910164 and MIR155 rs767649 Polymorphisms and Response to Anti-TNF Treatment in Patients with Crohn's Disease and Psoriasis

The clinical heterogeneity regarding the response profile of the antitumor necrosis factor (anti-TNF) in patients with Crohn's disease (CD) and psoriasis (PsO) is attributed, amongst others, to genetic factors that influence the regulatory mechanisms which orchestrate the inflammatory response. Here, we investigated the possible associations between the MIR146A rs2910164 and MIR155 rs767649 variants and the response to anti-TNF therapy in a Greek cohort of 103 CD and 100 PsO patients. We genotyped 103 CD patients and 100 PsO patients via the PCR-RFLP method, utilizing the de novo formation of a restriction site for the SacI enzyme considering the MIR146A rs2910164, while Tsp45I was employed for the MIR155 rs767649 variant. Additionally, we investigated the potential functional role of the rs767649 variant, exploring in silico the alteration of transcription factor binding sites (TFBSs) mapped on its genomic location. Our single-SNP analysis displayed a significant association between the rare rs767649 A allele and response to therapy (Bonferroni-corrected p value = 0.012) in patients with PsO, a result further enhanced by the alteration in the IRF2 TFBS caused by the above allele. Our results highlight the protective role of the rare rs767649 A allele in the clinical remission of PsO, implying its utilization as a pharmacogenetic biomarker.

MiRNA-Based Therapies for the Treatment of Inflammatory Bowel Disease: What Are We Still Missing?

Micro-RNAs (miRNAs) are noncoding RNAs usually 24-30 nucleotides long that play a central role in epigenetic mechanisms of inflammatory diseases and cancers. Recently, several studies have assessed the involvement of miRNAs in the pathogenesis of inflammatory bowel disease (IBD) and colitis-associated neoplasia. Particularly, it has been shown that many members of miRNAs family are involved in the pathways of inflammation and fibrogenesis of IBD; therefore, their use as inflammatory and fibrosis biomarkers has been postulated. In light of these results, the role of miRNAs in IBD therapy has been proposed and is currently under investigation with many in vitro and in vivo studies, murine models, and a phase 2a trial. The accumulating data have pushed miRNA-based therapy closer to clinical practice, although many open questions remain. With this systematic review, we discuss the current knowledge about the therapeutic effects of miRNAs mimicking and inhibition, and we explore the new potential targets of miRNA family for the treatment of inflammation and fibrosis in IBD.

Gluten-free diet affects fecal small non-coding RNA profiles and microbiome composition in celiac disease supporting a host-gut microbiota crosstalk

Current treatment for celiac disease (CD) is adhering to a gluten-free diet (GFD), although its long-term molecular effects are still undescribed. New molecular features detectable in stool may improve and facilitate noninvasive clinical management of CD. For this purpose, fecal small non-coding RNAs (sncRNAs) and gut microbiome profiles were concomitantly explored in CD subjects in relation to strict (or not) GFD adherence over time. In this observational study, we performed small RNA and shotgun metagenomic sequencing in stool from 63 treated CD (tCD) and 3 untreated subjects as well as 66 sex- and age-matched healthy controls. tCD included 51 individuals on strict GFD and with negative transglutaminase (TG) serology (tCD-TG-) and 12 symptomatic with not strict/short-time of GFD adherence and positive TG serology (tCD-TG+). Samples from additional 40 healthy adult individuals and a cohort of 19 untreated pediatric CD subjects and 19 sex/age matched controls were analyzed to further test the outcomes. Several miRNA and microbial profiles were altered in tCD subjects (adj. p < .05). Findings were validated in the external group of adult controls. In tCD-TG-, GFD duration correlated with five miRNA levels (p < .05): for miR-4533-3p and miR-2681-3p, the longer the diet adherence, the less the expression differed from controls. tCD-TG+ and untreated pediatric CD patients showed a similar miRNA dysregulation. Immune-response, trans-membrane transport and cell death pathways were enriched in targets of identified miRNAs. Bifidobacterium longum, Ruminococcus bicirculans, and Haemophilus parainfluenzae abundances shifted (adj. p < .05) with a progressive reduction of denitrification pathways with GFD length. Integrative analysis highlighted 121 miRNA-bacterial relationships (adj. p < .05). Specific molecular patterns in stool characterize CD subjects, reflecting either the long-term GFD effects or the gut inflammatory status, in case of a not strict/short-time adherence. Our findings suggest novel host-microbial interplays and could help the discovery of biomarkers for GFD monitoring over time.

The spring-like effect of microRNA-31 in balancing inflammatory and regenerative responses in colitis

Inflammatory bowel diseases (IBDs) are chronic inflammatory disorders caused by the disruption of immune tolerance to the gut microbiota. MicroRNA-31 (MIR31) has been proven to be up-regulated in intestinal tissues from patients with IBDs and colitis-associated neoplasias. While the functional role of MIR31 in colitis and related diseases remain elusive. Combining mathematical modeling and experimental analysis, we systematically explored the regulatory mechanism of MIR31 in inflammatory and epithelial regeneration responses in colitis. Level of MIR31 presents an "adaptation" behavior in dextran sulfate sodium (DSS)-induced colitis, and the similar behavior is also observed for the key cytokines of p65 and STAT3. Simulation analysis predicts MIR31 suppresses the activation of p65 and STAT3 but accelerates the recovery of epithelia in colitis, which are validated by our experimental observations. Further analysis reveals that the number of proliferative epithelial cells, which characterizes the inflammatory process and the recovery of epithelia in colitis, is mainly determined by the inhibition of MIR31 on IL17RA. MIR31 promotes epithelial regeneration in low levels of DSS-induced colitis but inhibits inflammation with high DSS levels, which is dominated by the competition for MIR31 to either inhibit inflammation or promote epithelial regeneration by binding to different targets. The binding probability determines the functional transformation of MIR31, but the functional strength is determined by MIR31 levels. Thus, the role of MIR31 in the inflammatory response can be described as the "spring-like effect," where DSS, MIR31 action strength, and proliferative epithelial cell number are regarded as external force, intrinsic spring force, and spring length, respectively. Overall, our study uncovers the vital roles of MIR31 in balancing inflammation and the recovery of epithelia in colitis, providing potential clues for the development of therapeutic targets in drug design.

MiRNA-374b-5p and miRNA-106a-5p are related to inflammatory bowel disease via regulating IL-10 and STAT3 signaling pathways

Background

Inflammatory bowel disease (IBD), including Crohn’s disease and ulcerative colitis, is one of the most frequent gastrointestinal disorders worldwide. Although the actual etiology of IBD remains unclear, growing evidence suggests that CD4+ T cells-associated cytokines, including interferon (IFN)-γ, interleukin (IL)-10 and IL-17A, are crucial for the occurrence of IBD. It has been reported that there is a positive association between miRNAs and IBD development. In this study, we investigated the roles of hsa-miRNA-374b-5p(miRNA-374b-5p) and hsa-miRNA-106a-5p(miRNA-106a-5p) in regulating IBD development.

Methods

Serum was obtained from vein blood of IBD patients and healthy controls, qRT-PCR was performed to study the expression of miRNA-374b-5p and miRNA-106a-5p. Furthermore, we investigate the effects of overexpression or inhibition of miRNA-374b-5p on naïve CD4 + T cell subsets differentiation from vein blood of healthy controls by RT-qPCR, flow cytometry and western blot. And more the prediction and confirmation of the targeting genes of miRNA-374b-5p and miRNA-106a-5p were performed by bioinformatics softwares and dual-luciferase reporter assay.

Results

The results showed that miRNA-106a-5p and miRNA-374b-5p were significantly overexpressed in IBD patients. MiRNA-374b-5p could enhance Th1/Th17 cell differentiation and was related to IBD pathogenesis. MiRNA-374b-5p overexpression induced the mRNA expression of IL-17A and IFN-γ, and suppressed that of IL-10 in T cells. MiRNA-374b-5p inhibition decreased the mRNA expression of IL-17A and IFN-γ, while upregulated that of IL-10 in T cells. These qPCR data were further verified at protein level by western blotting and flow cytometry. In addition, dual-luciferase reporter (DLR) assay indicated that miRNA-374b-5p was directly targeted by IL-10, a key anti-inflammatory cytokine for preventing the occurrence of IBD. Meanwhile, STAT3 was identified as a target gene of miRNA-106a-5p by DLR assays. Further analysis revealed that miRNA-374b-5p regulated JAK1 and STAT3 pathways in CD4+ T cells via IL-10/STAT3 axis. MiRNA-374b-5p overexpression remarkably decreased the mRNA expression and phosphorylated (ser-727) protein levels of STAT3, while miRNA-374b-5p inhibition had the opposite effects.

Conclusion

MiRNA-374b-5p and miRNA-106a-5p may contribute to IBD development by regulating IL-10/STAT3 signal transduction.

miRNAs Can Affect Intestinal Epithelial Barrier in Inflammatory Bowel Disease

The most obvious pathological characterization of inflammatory bowel disease (IBD) is intestinal epithelium erosion and severe inflammation invasion. Micro-ribonucleic acids (miRNA or microRNA), single-stranded noncoding RNAs of ~22 nucleotides, have been considered as the potential therapeutic targets in the pathogenesis of IBD. Many previous studies have focused on the mechanisms that miRNAs use to regulate inflammation, immunity, and microorganisms in IBD. The review highlights in detail the findings of miRNAs in the intestinal epithelial barrier of IBD, and focuses on their gene targets, signaling pathways associated with IBD, and some potential therapies. It will be beneficial for the elucidation of the interaction between miRNAs and the intestinal epithelial barrier in IBD and provide a theoretical reference for preventing and treating IBD in the future.

The role and mechanisms of miRNA in neonatal necrotizing enterocolitis

Neonatal necrotizing enterocolitis (NEC), the most significant causes of neonatal mortality, is a disease of acute intestinal inflammation. At present, it is not clear exactly how the disease is caused, but it has been suggested that this disorder is a result of a complex interaction among prematurity, enteral feeding and inappropriate pro-inflammation response and bacterial infection of the intestine. A microRNA (miRNA) is a class of endogenous non-coding single-stranded RNA that is about 23 nucleotides long engaging in the regulation of the gene expression. Recently, numerous studies have determined that abnormal miRNA expression plays important roles in various diseases, including NEC. Here, we summarized the role of miRNAs in NEC. We introduce the biosynthetic and function of miRNAs and then describe the possible mechanisms of miRNAs in the initiation and development of NEC, including their influence on the intestinal epithelial barrier's function and regulation of the inflammatory process. Finally, this review aids in a comprehensive understanding of the current miRNA to accurately predict the diagnosis of NEC and provide ideas to find potential therapeutic targets of miRNA for NEC. In conclusion, our aims are to highlight the close relationship between miRNAs and NEC and to summarize the practical value of developing diagnostic biomarkers and potential therapeutic targets of NEC.

MiR-145 regulates steroidogenesis in mouse primary granulosa cells through targeting Crkl

AIMS

It has been demonstrated that miR-145 is expressed in primordial follicles and modulates the initiation of primordial follicle development. We aimed to explore the function of miR-145 in mouse granulosa cells (mGCs).

MATERIALS AND METHODS

The proliferation and differentiation of GCs were examined via MTT, EDU assay, QRT-PCR, ELISA and electron microscope analysis. The target of miR-145 was determined by bioinformatics analysis and luciferase reporter assay and the molecular mechanisms were examined via western blot and quantitative Real-Time RT-PCR.

KEY FINDINGS

We proved that down-regulation of miR-145 could inhibit GCs proliferation and differentiation. In addition, we provided evidence that Crkl was the target gene of miR-145. The miR-145 antagomir caused an increase in Crkl expression and activation of the JNK/p38 MAPK pathway. Overexpression of Crkl with pEGFP-N1-Crkl vector inhibited GCs differentiation and progesterone synthesis as well as activation of the JNK/p38 MAPK pathway.

SIGNIFICANCE

Our study shows that miR-145 targets Crkl and through the JNK/p38 MAPK signaling pathway promotes the GCs proliferation, differentiation, and steroidogenesis. MiR-145 may play an important role in the ovarian physiology and pathology.