Angelos Oikonomopoulos

MicroRNA214 Is Associated With Progression of Ulcerative Colitis, and Inhibition Reduces Development of Colitis and Colitis-Associated Cancer in Mice

BACKGROUND & AIMS Persistent activation of the inflammatory response contributes to the development of inflammatory bowel diseases, which increase the risk of colorectal cancer. We aimed to identify microRNAs that regulate inflammation during the development of ulcerative colitis (UC) and progression to colitis-associated colon cancer (CAC). METHODS We performed a quantitative polymerase chain reaction analysis to measure microRNAs in 401 colon specimens from patients with UC, Crohns disease, irritable bowel syndrome, sporadic colorectal cancer, or CAC, as well as subjects without these disorders (controls); levels were correlated with clinical features and disease activity of patients. Colitis was induced in mice by administration of dextran sodium sulfate (DSS), and carcinogenesis was induced by addition of azoxymethane; some mice also were given an inhibitor of microRNA214 (miR214). RESULTS A high-throughput functional screen of the human microRNAome found that miR214 regulated the activity of nuclear factor-κB. Higher levels of miR214 were detected in colon tissues from patients with active UC or CAC than from patients with other disorders or controls and correlated with disease progression. Bioinformatic and genome-wide profile analyses showed that miR214 activates an inflammatory response and is amplified through a feedback loop circuit mediated by phosphatase and tensin homolog (PTEN) and PDZ and LIM domain 2 (PDLIM2). Interleukin-6 induced signal transducer and activator of transcription 3 (STAT3)-mediated transcription of miR214. A miR214 chemical inhibitor blocked this circuit and reduced the severity of DSS-induced colitis in mice, as well as the number and size of tumors that formed in mice given azoxymethane and DSS. In fresh colonic biopsy specimens from patients with active UC, the miR214 inhibitor reduced inflammation by increasing levels of PDLIM2 and PTEN. CONCLUSIONS Interleukin-6 up-regulates STAT3-mediated transcription of miR214 in colon tissues, which reduces levels of PDLIM2 and PTEN, increases phosphorylation of AKT, and activates nuclear factor-κB. The activity of this circuit correlates with disease activity in patients with UC and progression to colorectal cancer.

Optimization of human mesenchymal stem cell manufacturing: the effects of animal/xeno-free media

Due to their immunosuppressive properties, mesenchymal stem cells (MSC) have been evaluated for the treatment of immunological diseases. However, the animal-derived growth supplements utilized for MSC manufacturing may lead to clinical complications. Characterization of alternative media formulations is imperative for MSC therapeutic application. Human BMMSC and AdMSC were expanded in media supplemented with either human platelet lysates (HPL), serum-free media/xeno-free FDA-approved culture medium (SFM/XF), or fetal bovine serum (FBS) and the effects on their properties were investigated. The immunophenotype of resting and IFN-γ primed BMMSC and AdMSC remained unaltered in all media. Both HPL and SFM/XF increased the proliferation of BMMSC and AdMSC. Expansion of BMMSC and AdMSC in HPL increased their differentiation, compared to SFM/XF and FBS. Resting BMMSC and AdMSC, expanded in FBS or SFM/XF, demonstrated potent immunosuppressive properties in both non-primed and IFN-γ primed conditions, whereas HPL-expanded MSC exhibited diminished immunosuppressive properties. Finally, IFN-γ primed BMMSC and AdMSC expanded in SFM/XF and HPL expressed attenuated levels of IDO-1 compared to FBS. Herein, we provide strong evidence supporting the use of the FDA-approved SFM/XF medium, in contrast to the HPL medium, for the expansion of MSC towards therapeutic applications.

Assessment of Circulating MicroRNAs for the Diagnosis and Disease Activity Evaluation in Patients with Ulcerative Colitis by Using the Nanostring Technology

Background:Clinical decision and patient care management in inflammatory bowel diseases is largely based on the assessment of clinical symptoms, while the biomarkers currently in use poorly reflect the actual disease activity. Therefore, the identification of novel biomarkers will serve an unmet clinical need for IBD screening and patient management. We examined the utility of circulating microRNAs for diagnosis and disease activity monitoring in patients with ulcerative colitis (UC). Methods:Blood serum microRNAs were isolated from patients with UC with active and inactive disease and healthy donors. High-throughput microRNA profiling was performed using the Nanostring technology platform. Clinical disease activity was captured by calculating the partial Mayo score. C-reactive protein was measured in patients with UC as part of their clinical monitoring. The profiles of circulating microRNAs and C-reactive protein were correlated with clinical disease indices. Results:We have identified a signature of 12 circulating microRNAs that differentiate patients with UC from control subjects. Moreover, 6 of these microRNAs significantly correlated with UC disease activity. Importantly, a set of 4 microRNAs (hsa-miR-4454, hsa-miR-223-3p, hsa-miR-23a-3p, and hsa-miR-320e), which correlated with UC disease activity were found to have higher sensitivity and specificity values than C-reactive protein. Conclusions:Circulating microRNAs provide a novel diagnostic and prognostic marker for patients with UC. The use of an FDA-approved platform could accelerate the application of microRNA screening in a gastrointenstinal clinical setting. When used in combination with current diagnostic and disease activity assessment modalities, microRNAs could improve both IBD screening and care management.

A MicroRNA signature in pediatric ulcerative colitis: Deregulation of the miR-4284/CXCL5 pathway in the intestinal epithelium

Background:Twenty to 25% of the patients with inflammatory bowel disease (IBD) present the disease before the age of 18 to 20, with worse extent and severity, compared with adult-onset IBD. We sought to identify the differential expression of microRNAs in pediatric ulcerative colitis (UC) and their association with different clinical phenotypes. Methods:MicroRNA expression analysis was performed in colonic tissues derived from pediatric patients with UC and controls without IBD. MiR-4284 levels were verified by real-time quantitative polymerase chain reaction in 2 additional cohorts of pediatric patients with UC. Bioinformatics analysis was performed to predict the targets of miR-4284. In vitro experiments using luciferase reporter assays and real-time polymerase chain reaction evaluated the direct effect of miR-4284 on CXCL5 mRNA. In vivo experiments were performed in 2 mouse models of experimental colitis. Results:A 24-microRNA signature was identified in colonic tissues derived from pediatric patients with UC. The most downregulated microRNA in the tissue of pediatric patients UC, relative to non-IBD controls, was miR-4284. In situ hybridization revealed that miR-4284 is present in colonic epithelial cells, and its levels correlate with the disease activity. Furthermore, we found that miR-4284 regulates CXCL5 mRNA expression through binding to its 3′UTR. CXCL5 had increased mRNA levels in colonic tissue from pediatric patients with UC and correlated with disease activity. Furthermore, we found an inverse correlation between miR-4284 and CXCL5 levels in the colonic pediatric UC tissues and in 2 mouse models of experimental colitis. Conclusions:Our data reveal a novel microRNA pediatric UC signature and provide evidence that miR-4284 directly regulates CXCL5 and correlates with the disease activity.

Neurotensin—regulated miR-133α is involved in proinflammatory signalling in human colonic epithelial cells and in experimental colitis

Objective Neurotensin (NT) mediates colonic inflammation through its receptor neurotensin receptor 1 (NTR1). NT stimulates miR-133α expression in colonic epithelial cells. We investigated the role of miR-133α in NT-associated colonic inflammation in vitro and in vivo. Design miR-133α and aftiphilin (AFTPH) levels were measured by quantitative PCR. Antisense (as)-miR-133α was administrated intracolonicaly prior to induction of 2, 4, 6-trinitrobenzene sulfonic acid (TNBS)-induced colitis and dextran sodium sulfate (DSS)-induced colitis. The effect of AFTPH was examined by gene silencing in vitro. Results NT increased miR-133α levels in NCM-460 overexpressing NTR1 (NCM460-NTR1) and HCT-116 cells. NT-induced p38, ERK1/2, c-Jun, and NF-κB activation, as well as IL-6, IL-8 and IL-1β messenger RNA (mRNA) expression in NCM-460-NTR1 cells were reduced in miR-133α-silenced cells, while overexpression of miR-133α reversed these effects. MiR-133α levels were increased in TNBS (2 day) and DSS (5 day) colitis, while NTR1 deficient DSS-exposed mice had reduced miR-133α levels, compared to wild-type colitic mice. Intracolonic as-miR-133α attenuated several parameters of colitis as well expression of proinflammatory mediators in the colonic mucosa. In silico search coupled with qPCR identified AFTPH as a downstream target of miR-133α, while NT decreased AFTPH expression in NCM-460-NTR1 colonocytes. Gene silencing of AFTPH enhanced NT-induced proinflammatory responses and AFTPH levels were downregulated in experimental colitis. Levels of miR-133α were significantly upregulated, while AFTPH levels were downregulated in colonic biopsies of patients with ulcerative colitis compared to controls. Conclusions NT-associated colitis and inflammatory signalling are regulated by miR-133α-AFTPH interactions. Targeting of miR-133α or AFTPH may represent a novel therapeutic approach in inflammatory bowel disease.

Stem cell therapy in inflammatory bowel disease: which, when and how?

Purpose of review Stem cell therapy has emerged as a promising therapeutic strategy for inflammatory bowel diseases (IBDs). Currently, stem cell therapy is not part of the standard of care and is usually only performed as a part of clinical trials. In this review, clinical results, proposed underlying mechanisms, and future research directions will be discussed. Recent findings Administration of mesenchymal stem cells (MSCs) and hematopoietic stem cells (HSCs) has been evaluated for IBD treatment over the past years. MSC therapy is being explored as a treatment option for fistulizing Crohns disease and for luminal Crohns disease. It is shown to be well tolerated, but results on efficacy are inconsistent. HSC transplantation seems to be very effective, but serious adverse events are common. Therefore, future research should focus on improving efficacy of MSC therapy, and on improvement of safety of HSC therapy. Summary Both MSC and HSC therapy offer clinical potential, but currently are not routinely used for IBD treatment. MSC therapy seems well tolerated but results on efficacy are conflicting. HSC transplantation is shown to be effective but safety concerns remain. Nonetheless, for severe refractory IBD cases, stem cell therapy could well become the next-generation treatment option.

Anti-TNF Antibodies in Inflammatory Bowel Disease: Do We Finally Know How it Works?

Tumor necrosis factor (TNF) is a central pro-inflammatory cytokine that regulates the expression of numerous signaling pathways implicated in the progression of the immunological reaction. Unraveling the importance of TNF on the pathogenesis of inflammatory bowel disease (IBD) promoted anti-TNF antibodies as novel therapeutic agents. Initially, the main hypothesis behind the clinical application of anti-TNF antagonists in the clinic was that they exert their effects solely through neutralization of TNF. Anti-TNF antibodies induce and maintain clinical remission in patients with minimal side-effects. However, the cellular and molecular mechanisms of actions of the anti-TNF antibodies remain unknown. Various mechanisms of action have been proposed such as activation of transmembrane TNF mediated reverse signaling, induction of apoptosis, pro-inflammatory cytokine down-regulation, complement dependent cytotoxicity, antibodydependent cell-mediated cytotoxicity, and finally activation of regulatory immune cells via interactions with the Fc receptors. The observed discrepancies in the clinical efficacies as well as the differences in the structure of the various TNF antagonists nourish the investigation for additional modes of function.

Identification of Circulating MicroRNA Signatures in Crohn's Disease Using the Nanostring nCounter Technology.

Background:Current clinical indices, such as Harvey–Bradshaw index, are often inadequate for the assessment of disease activity in Crohns disease (CD). Alternative methods including imaging modalities and laboratory markers, such as C-reactive protein (CRP), are routinely applied to assess disease activity. However, laboratory markers poorly reflect the actual disease activity. Consequently, novel biomarkers represent a clinical necessity for CD patient management. We hypothesized that circulating serum-derived microRNAs may be used as diagnosis and disease activity monitoring tools of CD patients. Methods:To test this hypothesis, we performed microRNA expression profiling through Nanostring nCounter technology in blood serum samples of CD patients and healthy control subjects. Harvey–Bradshaw index score was used to capture clinical disease activity; CRP was measured as part of standard clinical practice. The expression profile of circulating microRNAs and the levels of CRP correlated with Harvey–Bradshaw index. Results:We identified a signature of 10 circulating microRNAs that are differentially expressed in CD patients compared with healthy control subjects. Two of these microRNAs (hsa-miR-1286 and hsa-miR-1273d) correlated with CD disease activity and exhibited higher correlation values compared with CRP. Further analysis revealed distinct microRNA signatures between CD patients with ileal and colonic involvement. Conclusions:Circulating microRNAs show superior value as diagnostic and disease activity markers in comparison to traditional methods. Circulating microRNAs could improve CD patient management, if applied in combination with current state-of-the-art diagnostic and disease activity assessment modalities.

The Xenobiotic Transporter Mdr1 Enforces T Cell Homeostasis in the Presence of Intestinal Bile Acids

Summary CD4+ T cells are tightly regulated by microbiota in the intestine, but whether intestinal T cells interface with host‐derived metabolites is less clear. Here, we show that CD4+ T effector (Teff) cells upregulated the xenobiotic transporter, Mdr1, in the ileum to maintain homeostasis in the presence of bile acids. Whereas wild‐type Teff cells upregulated Mdr1 in the ileum, those lacking Mdr1 displayed mucosal dysfunction and induced Crohn’s disease‐like ileitis following transfer into Rag1−/− hosts. Mdr1 mitigated oxidative stress and enforced homeostasis in Teff cells exposed to conjugated bile acids (CBAs), a class of liver‐derived emulsifying agents that actively circulate through the ileal mucosa. Blocking ileal CBA reabsorption in transferred Rag1−/− mice restored Mdr1‐deficient Teff cell homeostasis and attenuated ileitis. Further, a subset of ileal Crohn’s disease patients displayed MDR1 loss of function. Together, these results suggest that coordinated interaction between mucosal Teff cells and CBAs in the ileum regulate intestinal immune homeostasis. Graphical Abstract Figure. No caption available. HighlightsCD4+ effector T cells upregulate Mdr1 expression in the ileumMdr1 protects effector T cells in the ileum from bile‐acid‐driven oxidative stressBile acid sequestration restores Mdr1‐deficient T cell homeostasis in the ileumA subset of ileal Crohn’s disease patients display MDR1 loss of function &NA; The role of host‐derived intestinal metabolites in mucosal immune regulation is poorly understood. Here, Cao et al. show that effector CD4+ T cells upregulate expression of the xenobiotic transporter, Mdr1, in the ileum to safeguard immune homeostasis, revealing an important immunologic consequence of ileal bile acid reabsorption.

Circulating cathelicidin levels correlate with mucosal disease activity in ulcerative colitis, risk of intestinal stricture in Crohn’s disease, and clinical prognosis in inflammatory bowel disease

BackgroundCathelicidin (LL-37) is an antimicrobial peptide known to be associated with various autoimmune diseases. We attempt to determine if cathelicidin can accurately reflect IBD disease activity. We hypothesize that serum cathelicidin correlates with mucosal disease activity, stricture, and clinical prognosis of IBD patients.MethodsSerum samples were collected from two separate cohorts of patients at the University of California, Los Angeles. Cohort 1 consisted of 50 control, 23 UC, and 28 CD patients. Cohort 2 consisted of 20 control, 57 UC, and 67 CD patients. LL-37 levels were determined by ELISA. Data from both cohorts were combined for calculation of accuracies in indicating mucosal disease activity, relative risks of stricture, and odds ratios of predicting disease development.ResultsSerum cathelicidin levels were inversely correlated with Partial Mayo Scores of UC patients and Harvey-Bradshaw Indices of CD patients. Among IBD patients with moderate or severe initial disease activity, the patients with high initial LL-37 levels had significantly better recovery than the patients with low initial LL-37 levels after 6–18 months, suggesting that high LL-37 levels correlate with good prognosis. Co-evaluation of LL-37 and CRP levels was more accurate than CRP alone or LL-37 alone in the correlation with Mayo Endoscopic Score of UC patients. Low LL-37 levels indicated a significantly elevated risk of intestinal stricture in CD patients.ConclusionCo-evaluation of LL-37 and CRP can indicate mucosal disease activity in UC patients. LL-37 can predict future clinical activity in IBD patients and indicate risk of intestinal stricture in CD patients.