Therapeutic potential of the secreted Kazal-type serine protease inhibitor SPINK4 in colitis.

Mucus injury associated with goblet cell (GC) depletion constitutes an early event in inflammatory bowel disease (IBD). Using single-cell sequencing to detect critical events in mucus dysfunction, we discover that the Kazal-type serine protease inhibitor SPINK4 is dynamically regulated in colitic intestine in parallel with disease activities. Under chemically induced colitic conditions, the grim status in Spink4-conditional knockout mice is successfully rescued by recombinant murine SPINK4. Notably, its therapeutic potential is synergistic with existing TNF-α inhibitor infliximab in colitis treatment. Mechanistically, SPINK4 promotes GC differentiation using a Kazal-like motif to modulate EGFR-Wnt/ß-catenin and -Hippo pathways. Microbiota-derived diacylated lipoprotein Pam2CSK4 triggers SPINK4 production. We also show that monitoring SPINK4 in circulation is a reliable noninvasive technique to distinguish IBD patients from healthy controls and assess disease activity. Thus, SPINK4 serves as a serologic biomarker of IBD and has therapeutic potential for colitis via intrinsic EGFR activation in intestinal homeostasis.

Stanniocalcin-1 Promotes PARP1-Dependent Cell Death via JNK Activation in Colitis.

Stanniocalcin-1 (STC1) is upregulated by inflammation and modulates oxidative stress-induced cell death. Herein, the function of STC1 in colitis and stress-induced parthanatos, a newly identified type of programmed necrotic cell death dependent on the activation of poly-ADP ribose polymerase-1 (PARP1) is investigated. Results show that STC1 expression is markedly increased in the inflamed colonic mucosa of Crohn's disease (CD) patients and chemically-induced mice colitis models. Evaluation of parthanatos severity and pro-inflammatory cytokine expression shows that intestinal-specific Stc1 knockout (Stc1INT-KO ) mice are resistant to dextran sulfate sodium (DSS)-induced colitis and exhibit lower disease severity. STC1-overexpressing cells show an increased degree of parthanatos and proinflammatory cytokine expression, whereas STC1-knockout cells show a decreased degree of parthanatos. Co-immunoprecipitation, mass spectrometry, and proteomic analyses indicate that STC1 interacts with PARP1, which activates the JNK pathway via PARP1-JNK interactions. Moreover, inhibition of PARP1 and JNK alleviates parthanatos and inflammatory injuries triggered by STC1 overexpression. Finally, following restoration of Stc1 and Parp1 expression by adeno-associated viruses, and overexpression of Stc1 and Parp1 aggravated DSS-induced colitis in Stc1INT-KO mice. In conclusion, STC1 mediates oxidative stress-associated parthanatos and aggravates inflammation via the STC1-PARP1-JNK interactions and subsequent JNK pathway activation in CD pathogenesis.

Protocadherin 20 maintains intestinal barrier function to protect against Crohn's disease by targeting ATF6.

BACKGROUND: Intestinal barrier dysfunction plays a central role in the pathological onset of Crohn's disease. We identify the cadherin superfamily member protocadherin 20 (PCDH20) as a crucial factor in Crohn's disease. Here we describe the function of PCDH20 and its mechanisms in gut homeostasis, barrier integrity, and Crohn's disease development. RESULTS: PCDH20 mRNA and protein expression is significantly downregulated in the colonic epithelium of Crohn's disease patients and mice with induced colitis compared with controls. In mice, intestinal-specific Pcdh20 knockout causes defects in enterocyte proliferation and differentiation, while causing morphological abnormalities. Specifically, the deletion disrupts barrier integrity by unzipping adherens junctions via ß-catenin regulation and p120-catenin phosphorylation, thus aggravating colitis in DSS- and TNBS-induced colitis mouse models. Furthermore, we identify activating transcription factor 6 (ATF6), a key chaperone of endoplasmic reticulum stress, as a functional downstream effector of PCDH20. By administering a selective ATF6 activator, the impairment of intestinal barrier integrity and dysregulation of CHOP/ß-catenin/p-p120-catenin pathway was reversed in Pcdh20-ablated mice with colitis and PCDH20-deficient colonic cell lines. CONCLUSIONS: PCDH20 is an essential factor in maintaining intestinal epithelial homeostasis and barrier integrity. Specifically, PCDH20 helps to protect against colitis by tightening adherens junctions through the ATF6/CHOP/ß-catenin/p-p120-catenin axis.

Recent developments on BMPs and their antagonists in inflammatory bowel diseases.

Inflammatory bowel diseases (IBDs), including ulcerative colitis, and Crohn's disease, are intestinal disorders characterized by chronic relapsing inflammation. A large proportion of patients with IBD will progress to develop colitis-associated colorectal cancer due to the chronic intestinal inflammation. Biologic agents that target tumour necrosis factor-α, integrin α4ß7, and interleukin (IL)12/23p40 have been more successful than conventional therapies in treating IBD. However, drug intolerance and loss of response are serious drawbacks of current biologics, necessitating the development of novel drugs that target specific pathways in IBD pathogenesis. One promising group of candidate molecules are bone morphogenetic proteins (BMPs), members of the TGF-ß family involved in regulating morphogenesis, homeostasis, stemness, and inflammatory responses in the gastrointestinal tract. Also worth examining are BMP antagonists, major regulators of these proteins. Evidence has shown that BMPs (especially BMP4/6/7) and BMP antagonists (especially Gremlin1 and follistatin-like protein 1) play essential roles in IBD pathogenesis. In this review, we provide an updated overview on the involvement of BMPs and BMP antagonists in IBD pathogenesis and in regulating the fate of intestinal stem cells. We also described the expression patterns of BMPs and BMP antagonists along the intestinal crypt-villus axis. Lastly, we synthesized available research on negative regulators of BMP signalling. This review summarizes recent developments on BMPs and BMP antagonists in IBD pathogenesis, which provides novel insights into future therapeutic strategies.

A Novel Nomogram Combining Mucus Barrier Index for Predicting Treatment Failures in Ulcerative Colitis.

Background: Treatment failures (TFs) generally exist in the course of ulcerative colitis (UC), while early reliable predictors of TFs are still lacking. We aimed to generate nomograms for the prediction of TFs. Methods: In this retrospective case-control study, the endpoint was the occurrence of TFs, which included medically associated treatment failures and surgery-associated treatment failures (colectomy). Clinical features and mucus integrity evident by goblet cells (GCs) number, expression levels of MUC2 and SLC26A3 were enrolled in the univariate analysis. Nomogram performance was evaluated by discrimination and calibration. Results: We identified 256 UC patients at our center from January 2010 to June 2022. Fourteen variables for TFs and 9 for colectomy were identified by univariate analysis. Five baseline indices were incorporated into the nomogram for the prediction of TFs: area of GCs, age at diagnosis, disease duration, hemoglobin, and Mayo score. The model was presented with decent discrimination (C index of 0.822) and well calibration. In addition, the colectomy predictive nomogram was built using MUC2 intensity, age at onset, and Mayo score with a good discrimination (C index of 0.92). Conclusion: Nomograms based on comprehensive factors including mucus barrier function were developed to predict TFs in UC patients with great discrimination, which may serve as practical tools aiming to identify high-risk subgroups warrant timely intervention.

Role of Rho GTPases in inflammatory bowel disease.

Rat sarcoma virus homolog (Rho) guanosine triphosphatases (GTPases) function as "molecular switch" in cellular signaling regulation processes and are associated with the pathogenesis of inflammatory bowel disease (IBD). This chronic intestinal tract inflammation primarily encompasses two diseases: Crohn's disease and ulcerative colitis. The pathogenesis of IBD is complex and considered to include four main factors and their interactions: genetics, intestinal microbiota, immune system, and environment. Recently, several novel pathogenic components have been identified. In addition, potential therapies for IBD targeting Rho GTPases have emerged and proven to be clinically effective. This review mainly focuses on Rho GTPases and their possible mechanisms in IBD pathogenesis. The therapeutic possibility of Rho GTPases is also discussed.

Multi-Omics Analysis of Western-style Diet Increased Susceptibility to Experimental Colitis in Mice.

Background: Western-style diet (WSD) is associated with inflammatory bowel disease (IBD) prevalence. However, the impact of WSD on IBD development and its underlying mechanism remain unclear. Transcriptomics and metabolomics could be beneficial for identifying key factors in WSD-related experimental IBD susceptibility. However, no such study has been conducted yet. We aimed to analyze the implications of WSD for experimental colitis susceptibility in mice and its underlying mechanism using these high-throughput technologies. Methods: We fed experimental mice a WSD and a control diet from weaning. After 9 weeks, the mice were treated with 2,4,6 trinitrobenzene sulfonic acid to induce colitis, and the control group was treated with 50% ethanol (commonly used IBD animal model). Genome-wide microarray and liquid chromatography-tandem mass spectrometry were used to identify the differential transcripts and metabolites of experimental colitis with and without pre-illness WSD. Results: WSD induced more severe inflammation in experimental colitis than the control diet. We found 2540 up-regulated genes and 2737 down-regulated genes in experimental colitis with WSD compared with those for the control diet. In addition, levels of 41 colonic tissue metabolites and 56 serum metabolites showed significant differences. Integrating transcriptomic and metabolomic data, we found major co-expression networks through which WSD promoted experimental IBD susceptibility, including enzymes of biotransformation, glycan synthesis and metabolism, steroid hormone metabolites. Conclusion: Pre-illness WSD increased experimental colitis susceptibility. Our results could provide important evidences for the potential mechanisms and assist dietary recommendations to better manage IBD.

Serum exosomal microRNA-144-3p: a promising biomarker for monitoring Crohn's disease.

Background: Crohn's disease (CD) has a tendency for recurrence and requires adequate monitoring and personalized treatment. Since endoscopy is considerably invasive, serum biomarkers are required as alternatives for CD monitoring. Toward this, exosomal microRNAs (miRNAs) may serve as promising candidates. In this study, we aimed to assess the role of serum exosomal microRNA-144-3p (miR-144-3p) as a biomarker for CD monitoring. Methods: We prospectively recruited 154 patients without a history of surgery (Cohort 1) and 75 patients who were to undergo intestinal resection (Cohort 2). Serum samples were collected from Cohort 1 before colonoscopy and from Cohort 2 before surgery and during post-operative colonoscopic examination. The serum levels of exosomal miR-144-3p were measured using quantitative reverse-transcription polymerase chain reaction (PCR). Correlations between relative exosomal miR-144-3p levels, disease activity, and disease behavior were analysed. The area under the receiver-operating characteristic curve (AUC) was used to assess the predictive value of exosomal miR-144-3p regarding mucosal activity and post-operative recurrence. Results: A 3.33-fold increase in serum exosomal miR-144-3p levels was recorded in patients with CD compared with those in healthy controls (P < 0.001). The exosomal miR-144-3p levels were positively correlated with the simple endoscopic score of CD (ρ = 0.547, P < 0.001) as well as the Rutgeerts score (ρ = 0.478, P < 0.001). Elevated exosomal miR-144-3p levels were correlated with the penetrating disease with high specificity (100% [95% confidence interval, 95.1%-100%]). The accuracy of exosomal miR-144-3p for identifying post-operative recurrence was higher than that of C-reactive protein (CRP) (AUC, 0.775 vs 0.639; P < 0.001). Conclusions: Serum exosomal miR-144-3p is a reliable biomarker of mucosal inflammation and penetrating CD. It may identify endoscopic CD recurrence after intestinal resection with higher accuracy than CRP testing.

Development and validation of a non-invasive biomarker-based model to identify endoscopic recurrences of Crohn's disease.

Background: Endoscopic recurrence is common in postoperative patients with Crohn's disease (CD). Monitoring endoscopic recurrence is important for selecting an appropriate treatment to prevent the development of postoperative disease. The aim of this study was to develop and validate a diagnostic model to identify endoscopic recurrence. Methods: This was a retrospective cohort study recruiting postoperative CD patients who underwent endoscopy at the First Affiliated Hospital, Sun Yat-sen University from January 2016 to June 2020. Endoscopic recurrence was defined as Rutgeerts score > i1. Thirty non-invasive biomarkers, including C-reactive protein, erythrocyte sedimentation rate, vitamin D, complete blood count, and biochemical blood indices, were used as candidate predictors to build a multivariate logistic regression diagnostic model. The predictive ability of the diagnostic models was assessed by receiving the area under the characteristic curve (AUC) and calibration plots, and internal validation was performed by the bootstrap method. Results: Two hundred and nineteen eligible patients were included in this study, and 135 (61.6%) patients had a postoperative endoscopic recurrence. The final diagnostic model included eight biomarkers with an AUC (95% confidence interval (CI)) of 0.796 (0.737-0.855) to identify endoscopic recurrence. The AUC, sensitivity, and specificity of this diagnostic model were 0.781 (0.780-0.782), 0.647 (0.643-0.651) and 0.811 (0.807-0.815), respectively, by internal validation. In addition, the diagnostic model exhibited good calibrability with calibration slope, calibration-in-the-large ('mean calibration') and Brier scores of 1.00, 0.00, and 0.175, respectively. Conclusion: This non-invasive biomarker-based diagnostic model has an excellent ability to identify endoscopic recurrence in patients with CD. Application of the model to clinical practice to monitor postoperative patients may be helpful for patient management.

Hypermethylation of miR-145 promoter-mediated SOX9-CLDN8 pathway regulates intestinal mucosal barrier in Crohn's disease.

BACKGROUND: Intestinal barrier impairment plays an essential role in the pathogenesis of Crohn's disease (CD), and claudins (CLDNs) dysfunction contributes to intestinal mucosa injury. SOX9, an important transcription factor, is upregulated in the disease-affected colon of patients with CD; however, its precise role in CD remains largely unknown. Our aim was to explore the interaction between SOX9 and CLDNs, and further elucidate the underlying mechanisms in CD. METHODS: SOX9 expression in patients with CD was evaluated using quantitative polymerase chain reaction, immunoblotting, and immunohistochemistry. The regulatory relationship between SOX9 and CLDNs was analyzed via a dual-luciferase reporter assay, chromatin immunoprecipitation, overexpression, and RNA interference methods. MicroRNAs (miRNAs) involved in the SOX9-CLDN pathway were predicted with bioinformatics analysis, and the upstream molecular mechanism was interpreted using MassARRAY methylation detection. FINDINGS: Upregulated expression of SOX9 in the disease-affected intestine mucosa was identified in both patients with CD and mice challenged with trinitrobenzene sulfonic acid (TNBS). SOX9 negatively regulated the expression of CLDN8, accompanying reduced intestinal permeability. MiR-145-5p downregulation was found in patients with CD and TNBS-induced colitis mice owing to an aberrant miR-145 promoter hypermethylation, which subsequently interfered the SOX9-CLDN8 pathway. MiR-145-5p agomir treatment alleviated TNBS-induced colitis in wild-type mice by inhibiting Sox9 expression and restoring Cldn8 expression, whereas similar findings were not apparent in the Cldn8-/- mice. INTERPRETATION: SOX9 mediates the crosstalk between upstream miR-145-5p and downstream CLDN8, and further impairs intestinal mucosal barrier homeostasis in CD. Targeting the miR-145-5p/SOX9/CLDN8 pathway represents a promising therapeutic strategy for CD. FUNDING: The National Natural Science Foundation of China (#81870374, #81670498, #81630018, #82070538, #8210031148), the Guangdong Science and Technology (#2017A030306021, #2020A1515111087), the Guangzhou Science and Technology Department (#202002030041), and the Fundamental Research Funds for the Central Universities (#19ykzd11).

Emerging roles of the Hedgehog signalling pathway in inflammatory bowel disease.

The Hedgehog (Hh) signalling pathway plays a critical role in the growth and patterning during embryonic development and maintenance of adult tissue homeostasis. Emerging data indicate that Hh signalling is implicated in the pathogenesis of inflammatory bowel disease (IBD). Current therapeutic treatments for IBD require optimisation, and novel effective drugs are warranted. Targeting the Hh signalling pathway may pave the way for successful IBD treatment. In this review, we introduce the molecular mechanisms underlying the Hh signalling pathway and its role in maintaining intestinal homeostasis. Then, we present interactions between the Hh signalling and other pathways involved in IBD and colitis-associated colorectal cancer (CAC), such as the Wnt and nuclear factor-kappa B (NF-κB) pathways. Furthermore, we summarise the latest research on Hh signalling associated with the occurrence and progression of IBD and CAC. Finally, we discuss the future directions for research on the role of Hh signalling in IBD pathogenesis and provide viewpoints on novel treatment options for IBD by targeting Hh signalling. An in-depth understanding of the complex role of Hh signalling in IBD pathogenesis will contribute to the development of new effective therapies for IBD patients.

A Novel Model Based on Serum Biomarkers to Predict Primary Non-Response to Infliximab in Crohn's Disease.

Background: Infliximab is effective in inducing and maintaining remission in patients with Crohn's disease (CD), but primary non-response (PNR) occurs in 10-30% of cases. We investigated whether serum biomarkers are effective in predicting PNR in patients with CD. Methods: From January 2016 to April 2020, a total of 260 patients were recruited to this prospective and retrospective cohort study. Serum samples were collected at baseline and week 2 of infliximab treatment. Serum levels of 35 cytokines were assessed in 18 patients from the discovery cohort and were further evaluated in the 60-patient cohort 1. Then, candidate cytokines and other serological biomarkers were used to construct a predictive model by logistic regression in a 182-patient cohort 2. PNR was defined based on the change of CD activity index or clinical symptoms. Results: Among the 35 cytokines, matrix metalloproteinase 3(MMP3) and C-C motif ligand 2 (CCL2) were two effective serum biomarkers associated with PNR in both the discovery cohort and cohort 1. In cohort 2, serum level of MMP3, CCL2 and C-reactive protein (CRP) at 2 weeks after infliximab injection were independent predictors of PNR, with odds ratios (95% confidence interval) of 1.108(1.059-1.159), 0.940(0.920-0.965) and 1.102(1.031-1.117), respectively. A PNR classifier combining these three indicators had a large area under the curve [0.896(95% CI:0.895-0.897)] and negative predictive value [0.918(95%CI:0.917-0.919)] to predict PNR to infliximab. Conclusions: MMP3, CCL2, and CRP are promising biomarkers in prediction of PNR to infliximab, and PNR classifier could accurately predict PNR and may be useful in clinical practice for therapy selection.

MALAT1 Maintains the Intestinal Mucosal Homeostasis in Crohn's Disease via the miR-146b-5p-CLDN11/NUMB Pathway.

BACKGROUND AND AIMS: Intestinal homeostasis disorder is critical for developing Crohn's disease [CD]. Maintaining mucosal barrier integrity is essential for intestinal homeostasis, preventing intestinal injury and complications. Among the remarkably altered long non-coding RNAs [lncRNAs] in CD, we aimed to investigate whether metastasis-associated lung adenocarcinoma transcript 1 [MALAT1] modulated CD and consequent disruption of intestinal homeostasis. METHODS: Microarray analyses on intestinal mucosa of CD patients and controls were performed to identify dysregulated lncRNAs. MALAT1 expression was investigated via qRT-PCR and its distribution in intestinal tissues was detected using BaseScope. Intestines from MALAT1 knockout mice with colitis were investigated using histological, molecular, and biochemical approaches. Effects of intestinal epithelial cells, transfected with MALAT1 lentiviruses and Smart Silencer, on monolayer permeability and apical junction complex [AJC] proteins were analysed. MiR-146b-5p was confirmed as a critical MALAT1 mediator in cells transfected with miR-146b-5p mimic/inhibitor and in colitis mice administered agomir-146b-5p/antagomir-146b-5p. Interaction between MALAT1 and miR-146b-5p was predicted via bioinformatics and validated using Dual-luciferase reporter assay and Ago2-RIP. RESULTS: MALAT1 was aberrantly downregulated in the intestine mucosa of CD patients and mice with experimental colitis. MALAT1 knockout mice were hypersensitive to DSS-induced experimental colitis. MALAT1 regulated the intestinal mucosal barrier and regained intestinal homeostasis by sequestering miR-146b-5p and maintaining the expression of the AJC proteins NUMB and CLDN11. CONCLUSIONS: Downregulation of MALAT1 contributed to the pathogenesis of CD by disrupting AJC. Thus, a specific MALAT1-miR-146b-5p-NUMB/CLDN11 pathway that plays a vital role in maintaining intestinal mucosal homeostasis may serve as a novel target for CD treatment.

Fecal Microbiota Alterations Associated With Clinical and Endoscopic Response to Infliximab Therapy in Crohn's Disease.

BACKGROUND: Gut microbiota dysbiosis is associated with the occurrence and development of Crohn disease (CD). Currently, infliximab (IFX) is used more and more to treat CD; however, gut microbiota alterations during IFX therapy are variable and sometimes even contradictory. We longitudinally identified microbial changes during IFX therapy associated with the clinical and endoscopic response to IFX treatment in CD. METHODS: Fecal-associated microbiota was analyzed using 16S sequencing in 49 patients with active CD who were prospectively recruited at baseline, week 6, and week 30, respectively. Moreover, a model trained on the gut microbiota alterations at week 6 was developed to investigate their potential to predict clinical and endoscopic responses to IFX therapy at weeks 14 and 30. RESULTS: Characteristics of fecal microbiota composition in patients with CD after IFX treatment displayed an increased diversity and richness, a significant gain in short-chain fatty acid -producing bacteria, and a loss of pathogenic bacteria. Furthermore, certain functional profiles of Kyoto Encyclopedia of Genes and Genomes pathways were predictably altered during the treatment period. Increased proportions of Lachnospiraceae and Blautia were associated with IFX efficacy; the combined increase of these taxa at week 6 showed 83.4% and 84.2% accuracy in predicting clinical response at weeks 14 and 30, respectively, with a predictive value of 89.1% in predicting endoscopic response at week 30. CONCLUSIONS: We found that IFX diminished CD-related gut microbial dysbiosis by modifying microbiota composition and function. Specifically, increased Lachnospiraceae and Blautia at week 6 are associated with the clinical and endoscopic response to IFX, providing potentially predictive biomarkers for IFX treatment decision-making.

Which long noncoding RNAs and circular RNAs contribute to inflammatory bowel disease?

Inflammatory bowel disease (IBD), a chronic relapsing gastrointestinal inflammatory disease, mainly comprises ulcerative colitis (UC) and Crohn's disease (CD). Although the mechanisms and pathways of IBD have been widely examined in recent decades, its exact pathogenesis remains unclear. Studies have focused on the discovery of new therapeutic targets and application of precision medicine. Recently, a strong connection between IBD and noncoding RNAs (ncRNAs) has been reported. ncRNAs include microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs). The contributions of lncRNAs and circRNAs in IBD are less well-studied compared with those of miRNAs. However, lncRNAs and circRNAs are likely to drive personalized therapy for IBD. They will enable accurate diagnosis, prognosis, and prediction of therapeutic responses and promote IBD therapy. Herein, we briefly describe the molecular functions of lncRNAs and circRNAs and provide an overview of the current knowledge of the altered expression profiles of lncRNAs and circRNAs in patients with IBD. Further, we discuss how these RNAs are involved in the nosogenesis of IBD and are emerging as biomarkers.

Serum Biomarkers for Inflammatory Bowel Disease.

Background: Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, is a chronic, inflammatory disorder of the gastrointestinal tract. As the novel therapeutic goal and biologicals are widely recognized, accurate assessment of disease and prediction of therapeutic response have become a crucial challenge in clinical practice. Also, because of the continuously rising incidence, convenient and economical methods of diagnosis and clinical assessment are urgently needed. Recently, serum biomarkers have made a great progress and become a focus in IBD study because they are non-invasive, convenient, and relatively inexpensive than are markers in biopsy tissue, stool, breath, and other body fluids. Aims: To review the available data on serological biomarkers for IBD. Methods: We searched PubMed using predefined key words on relevant literatures of serum biomarkers regarding diagnosis, evaluation of therapeutic efficacy, surveillance of disease activity, and assessment of prognosis for IBD. Results: We reviewed serological biomarkers that are well-established and widely used (e.g., C-reactive protein), newly discovered biomarkers (e.g., cytokines, antibodies, and non-coding RNAs), and also recently advancements in serological biomarkers (e.g., metabolomics and proteomics) that are used in different aspects of IBD management. Conclusions: With such a wealth of researches, to date, there are still no ideal serum biomarkers for IBD. Serum profiling and non-coding RNAs are just starting to blossom but reveal great promise for future clinical practice. Combining different biomarkers can be valuable in improving performance of disease evaluation.

Platelet-to-lymphocyte percentage ratio index: a simple non-invasive index to monitor the endoscopic activity in Crohn's disease.

BACKGROUND: Recent evidence has shown that the complete blood count (CBC) is abnormal in patients with Crohn's disease (CD). We aimed to investigate an effective CBC parameter and explore its impact on disease activity in a large CD cohort. METHODS: We performed a retrospective analysis of patients with established CD who underwent clinically indicated endoscopy at four tertiary centres in China between 2016 and 2020. Individual variables of the Simple Endoscopic Score for CD, CBC parameters, C-reactive protein (CRP) levels, erythrocyte sedimentation rate, and faecal calprotectin (FC) were independently reviewed by different investigators. The hold-out method was used to verify the predictive power of the established model. RESULTS: Data from a total of 1388 endoscopic procedures performed for 882 eligible CD patients were available with routine blood parameters and related indicators. The model using platelet-to-lymphocyte percentage ratio (PLpR) had high accuracy for identifying patients in endoscopic remission (ER), with an area under the curve (AUC) of 0.785 [95% confidence interval (CI): 0.784-0.787], which was comparable with that for CRP (AUC: 0.775, 95% CI: 0.774-0.777). Notably, the AUC of PLpR was significantly higher than that of CRP in patients with colonic disease and with a history of surgery. Moreover, after combining the FC with PLpR, the AUC value of FC + PLpR increased up to 0.892 (95% CI: 0.890-0.894) for identifying ER. CONCLUSIONS: We explored an index (PLpR) to identify CD patients in ER based on platelet and lymphocyte percentage from the CBC. PLpR helped evaluate the degree of disease activity and monitor the therapeutic response.

Circulating microRNA146b-5p is superior to C-reactive protein as a novel biomarker for monitoring inflammatory bowel disease.

BACKGROUND: Owing to the importance of early treatment, simple and reliable methods for monitoring inflammatory bowel disease (IBD) are needed. AIMS: To determine whether circulating microRNAs are reliable biomarkers for IBD monitoring. METHODS: Serum levels of 17 candidate microRNAs were measured by quantitative real-time polymerase chain reaction in a discovery cohort (n = 120). Differentially expressed serum microRNAs were further investigated in an independent training cohort (n = 341). Correlations between relative microRNA levels and disease activity were evaluated. A disease control group was included to investigate the specificity of microRNA. Logistical regression was used to construct a microRNA classifier to identify endoscopic activity. Its predictive value was explored in the validation cohort (n = 66) using the area under the receiver operating characteristic curve (AUC). RESULTS: Serum microRNA146b-5p (miR-146b-5p) expression was 2.87- and 2.72-fold higher in patients with Crohn's disease and ulcerative colitis, respectively, than in healthy controls. Serum miR-146b-5p was significantly correlated with disease activity and was more specific than C-reactive protein (CRP). A classifier was built for Crohn's disease, ie P [Endoscopically active] = 11+e2.937-0.737(miR-146b-5p)-0.008PLT , with a greater AUC of 0.869 [0.764-0.940] than that for CRP (0.680 [0.554-0.790]) (P = 0.0043). CONCLUSIONS: MiR-146b-5p may better reflect mucosal inflammation in IBD than CRP. The Crohn's disease classifier developed in this study may be valuable for identifying endoscopic activity in patients with Crohn's disease.

Cytokine IL9 Triggers the Pathogenesis of Inflammatory Bowel Disease Through the miR21-CLDN8 Pathway.

Background: Cytokine interleukin-9 (IL9) plays an essential role in the pathogenesis of inflammatory bowel disease. However, the molecular mechanism underlying the IL9 pathway remains unknown. Here, we initiate a series of studies to characterize the essential components of this pathway. Methods: The expression of IL9 in colon biopsies from Crohn's disease (CD) and controls were examined by quantitative polymerase chain reaction, immunoblot, and immunohistochemistry. The trinitrobenzene sulfonic acid (TNBS)-induced colitis model was used to verify the therapeutic efficiency of anti-IL9 mAb. Bioinformatics analysis was performed to predict putative candidate microRNAs that mediate the crosstalk between the IL9 proinflammatory signal and the downstream target gene in intestinal barrier function. Caco-2, NCM460, and SW480 cells were used to assess the specific pathway in vitro. Results: We demonstrated the proinflammatory role of IL9 in the colonic mucosa of patients with CD. The junction complex protein Claudin 8 (CLDN8) was identified as a critical downstream component of the IL9 inflammatory cascade. Anti-IL9 treatment alleviated TNBS-induced colitis by restoring CLDN8 levels in the colonic mucosa. Notably, we characterized miR21 as a critical player that mediates the crosstalk between the proinflammatory IL9 and the downstream CLDN8 in both in vitro and in vivo models. Conclusions: Our results, for the first time, uncover a critical role of miR21 and CLDN8 in the complex network that IL9 regulates the intestinal epithelium barrier in the pathogenesis of CD. Interventional blockade of the IL9-miR21-CLDN8 pathway could be a novel therapeutic approach for the management of CD.