MicroRNAs as tools to predict glucocorticoid response in inflammatory bowel diseases

miR-331-3p is involved in glucocorticoid resistance reversion by rapamycin through suppression of the MAPK signaling pathway

Glucocorticoids (GCs) are commonly used as therapeutic agents for immune-mediated diseases and leukemia. However, considerable inter-individual differences in efficacy have been reported. Several reports indicate that the inhibitor of mTOR rapamycin can reverse GC resistance, but the molecular mechanism involved in this synergistic effect has not been fully defined. In this context, we explored the differential miRNA expression in a GC-resistant CCRF-CEM cell line after treatment with rapamycin alone or in co-treatment with methylprednisolone (MP). The expression analysis identified 70, 99 and 96 miRNAs that were differentially expressed after treatment with MP, rapamycin and their combination compared to non-treated controls, respectively. Two pathways were exclusively altered as a result of the co-treatment: the MAPK and ErbB pathways. We validated the only miRNA upregulated specifically by the co-treatment associated with the MAPK signaling, miR-331-3p. Looking for miR-331-3p targets, MAP2K7, an essential component of the JNK/MAPK pathway, was identified. Interestingly, MAP2K7 expression was downregulated during the co-treatment, causing a decrease in terms of JNK activity. miR-331-3p in mimic-transfected cells led to a significant decrease in MAP2K7 levels and promoted the reversion of GC resistance in vitro. Interestingly, miR-331-3p expression was also associated with GC-resistance in patient leukemia cells taken at diagnosis. The combination of rapamycin with MP restores GC effectiveness through the regulation of different miRNAs, suggesting the important role of these pharmacoepigenetic factors in GC response.

Pharmacogenetics of treatments for inflammatory bowel disease

INTRODUCTION

Inflammatory bowel disease is a chronic inflammation of the gut whose pathogenesis is still unclear. Although no curative therapy is currently available, a number of drugs are used in induction and maintenance therapy; however, for most of these drugs, a high inter-individual variability in response is observed. Among the factors of this variability, genetics plays an important role. Areas covered: This review summarizes the results of pharmacogenetic studies, considering the most important drugs used and in particular aminosalycilates, glucocorticoids, thiopurines, monoclonal antibodies and thalidomide. Most studies used a candidate gene approach, even if significant breakthroughs have been obtained recently from applying genome-wide studies. When available, also investigations considering epigenetics and pharmacogenetic dosing guidelines have been included. Expert opinion: Only for thiopurines, genetic markers identified as predictors of efficacy or adverse events have allowed the development of dosing guidelines. For the other drugs, encouraging results are available and great expectations rely on the study of epigenetics and integration with pharmacokinetic information, especially useful for biologics. However, to improve therapy of IBD patients with these drugs, for implementation in the clinics of pharmacogenetics, informatic clinical decision support systems and training about pharmacogenetics of health providers are needed.

Biomarkers in inflammatory bowel diseases: insight into diagnosis, prognosis and treatment

Inflammatory bowel disease (IBD) is a chronic disease of unknown etiology which mostly involves the intestine and requires a personalized approach for treatment. IBD represents a heterogeneous group of patients with inherently variable disease courses. Hence, the heterogeneity of patient populations may delay the diagnosis, clinical practice and initiation of appropriate treatment. Use of biomarkers for diagnosis and management of IBD is still necessary. Descriptions of the immunological pathway abnormalities in IBD improve assessment to identify the patient's disease status, and relative risk of progression to complicated disease behaviors, and this information may ultimately influence therapeutic decisions. In this study, we try to explain the role of biomarkers in early diagnosis, estimating prognosis, and target agents for correct managements of IBD's patients. This information might be important to provide insight into emerging panels of multiple IBD biomarkers and highlighting the essential role of personalizes panel for each patient.

The Role of Laboratory Tests in Crohn's Disease

In the past, laboratory tests were considered of limited value in Crohn's disease (CD). In the era of biologics, laboratory tests have become essential to evaluate the inflammatory burden of the disease (C-reactive protein, fecal calprotectin) since symptoms-based scores are subjective, to predict the response to pharmacological options and the risk of relapse, to discriminate CD from ulcerative colitis, to select candidates to anti-tumor necrosis factors [screening tests looking for hepatitis B virus and hepatitis C virus status and latent tuberculosis], to assess the risk of adverse events (testing for thiopurine metabolites and thiopurine-methyltransferase activity), and to personalize and optimize therapy (therapeutic drug monitoring). Pharmacogenetics, though presently confined to the assessment of thiopurineme methyltransferase polymorphisms and hematological toxicity associated with thiopurine treatment, is a promising field that will contribute to a better understanding of the molecular mechanisms of the variability in response to the drugs used in CD with the attempt to expand personalized care and precision medicine strategies.

Emerging Biomarkers for the Diagnosis and Monitoring of Inflammatory Bowel Diseases

There is currently no single test available to confidently diagnose cases of inflammatory bowel disease (IBD). Physicians rely on a number of diagnostic tools, including clinical evaluation, serum testing, and imaging, which are used on conjunction with endoscopic evaluation. It is often difficult to determine whether patients with abdominal pain and change in bowel habit have functional bowel symptoms or whether they have a true diagnosis of IBD. Even once a diagnosis of IBD has been made, a significant proportion of patients are labeled with the term "indeterminate colitis" where histological sampling cannot confidently subclassify patients as either Crohn's or ulcerative colitis. Colonoscopy is an inconvenient and uncomfortable test for most patients. In addition, it is not without serious risks of perforation, as well as risks which can be associated with sedation and analgesia given during the procedure. The use of biomarkers to aid in the diagnosis, subclassification, and monitoring of IBD is an ever expanding area. In this review, we have concentrated on noninvasive biomarkers of IBD, because these are more acceptable to patients and easier to perform in everyday clinical practice. We will first touch on those biomarkers currently well established and in wide clinical use, such as C-reactive protein, erythrocyte sedimentation rate. Faecal calprotectin and their use in the diagnosis of IBD. Following on, we will review more novel biomarkers and their use in subclassification and monitoring of IBD, including a variety of antibodies, genetics, and microRNAs, as well as touching on metabolomics.

Glucocorticoids impair bone formation of bone marrow stromal stem cells by reciprocally regulating microRNA-34a-5p

The inhibitory effects of glucocorticoids (GCs) on bone marrow stromal stem cell (BMSC) proliferation and osteoblastic differentiation are an important pathway through which GCs decrease bone formation. We found that microRNA-34a-5p was a critical player in dexamethasone (Dex)-inhibited BMSC proliferation and osteogenic differentiation. MicroRNA-34a-5p might be used as a therapeutic target for GC-impaired bone formation.

INTRODUCTION

The inhibitory effects of glucocorticoids (GCs) on bone marrow stromal stem cell (BMSC) proliferation and osteoblastic differentiation are an important pathway through which GCs decrease bone formation. The mechanisms of this process are still not completely understood. Recent studies implicated an important role of microRNAs in GC-mediated responses in various cellular processes, including cell proliferation and differentiation. Therefore, we hypothesized that these regulatory molecules might be implicated in the process of GC-decreased BMSC proliferation and osteoblastic differentiation.

METHODS

Western blot, quantitative real-time PCR, and cell proliferation and osteoblastic differentiation assays were employed to investigate the role of microRNAs in GC-inhibited BMSC proliferation and osteoblastic differentiation.

RESULTS

We found that microRNA-34a-5p was reciprocally regulated by Dex during the process of BMSC proliferation and osteoblastic differentiation. Furthermore, we confirmed that microRNA-34a-5p was a critical player in Dex-inhibited BMSC proliferation and osteogenic differentiation. Mechanistic studies showed that Dex inhibited BMSC proliferation by microRNA-34a-5p targeting cell cycle factors, including CDK4, CDK6, and Cyclin D1. Furthermore, downregulation of microRNA-34a-5p by Dex leads to Notch signaling activation, resulting in inhibition of BMSC osteogenic differentiation.

CONCLUSIONS

These results showed that microRNA-34a-5p, a crucial regulator for BMSC proliferation and osteogenic differentiation, might be used as a therapeutic target for GC-impaired bone formation.

Update on pathogenesis and predictors of response of therapeutic strategies used in inflammatory bowel disease

The search for biomarkers that characterize specific aspects of inflammatory bowel disease (IBD), has received substantial interest in the past years and is moving forward rapidly with the help of modern technologies. Nevertheless, there is a direct demand to identify adequate biomarkers for predicting and evaluating therapeutic response to different therapies. In this subset, pharmacogenetics deserves more attention as part of the endeavor to provide personalized medicine. The ultimate goal in this area is the adjustment of medication for a patient’s specific genetic background and thereby to improve drug efficacy and safety rates. The aim of the following review is to utilize the latest knowledge on immunopathogenesis of IBD and update the findings on the field of Immunology and Genetics, to evaluate the response to the different therapies. In the present article, more than 400 publications were reviewed but finally 287 included based on design, reproducibility (or expectancy to be reproducible and translationable into humans) or already measured in humans. A few tests have shown clinical applicability. Other, i.e., genetic associations for the different therapies in IBD have not yet shown consistent or robust results. In the close future it is anticipated that this, cellular and genetic material, as well as the determination of biomarkers will be implemented in an integrated molecular diagnostic and prognostic approach to manage IBD patients.

MicroRNA-24 inhibits serotonin reuptake transporter expression and aggravates irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common chronic functional gastrointestinal disorder. MicroRNAs (miRNAs) have been widely demonstrated to take part in various physiological and pathological processes. In the present study, the role of miR-24 in the pathogenesis of IBS and the potential mechanism in this process were evaluated. Human intestinal mucosa epithelial cells of colon from IBS patients and healthy subjects were collected. An IBS mouse model was established with the induction of trinitro-benzene-sulfonic acid (TNBS). The expression levels of miR-24 and serotonin reuptake transporter (SERT) were analyzed using Real-time PCR and western blot in both human specimen and mice. miR-24 was upregulated in IBS patients and mice intestinal mucosa epithelial cells. Luciferase reporter assay showed that SERT was a potential target gene of miR-24. The treatment of miR-24 inhibitor increased pain threshold and nociceptive threshold levels and reduced MPO activity in proximal colon of IBS mice, and up-regulated the mRNA and protein expression levels of SERT in intestinal mucosa epithelial cells. miR-24 played a role in the pathogenesis of IBS probably through regulating SERT expression.

microRNAs as pharmacogenomic biomarkers for drug efficacy and drug safety assessment

Much evidence has documented that microRNAs (miRNAs) play an important role in the modulation of interindividual variability in the production of drug metabolizing enzymes and transporters (DMETs) and nuclear receptors (NRs) through multidirectional interactions involving environmental stimuli/stressors, the expression of miRNA molecules and genetic polymorphisms. MiRNA expression has been reported to be affected by drugs and miRNAs themselves may affect drug metabolism and toxicity. In cancer research, miRNA biomarkers have been identified to mediate intrinsic and acquired resistance to cancer therapies. In drug safety assessment, miRNAs have been found associated with cardiotoxicity, hepatotoxicity and nephrotoxicity. This review article summarizes published studies to show that miRNAs can serve as early biomarkers for the evaluation of drug efficacy and drug safety.

MicroRNA markers of inflammation and remodelling in temporal arteries from patients with giant cell arteritis

OBJECTIVES

There is increasing evidence that microRNAs (miRNAs) are deregulated in autoimmune and cardiovascular diseases. The present study aimed to identify if miRNAs are deregulated in giant cell arteritis (GCA), a vasculitis affecting large-sized and medium-sized arteries, and to determine if miRNA levels might allow to discriminate between patients with GCA and those without.

METHODS

58 patients who had temporal artery biopsy (TAB) for suspected GCA were included in the study and divided into three groups: patients with TAB-positive GCA showing a transmural inflammation (n=27), patients with TAB-negative GCA (n=8) and TAB-negative non-GCA patients with a final diagnosis different from GCA (n=23). To identify candidate miRNAs deregulated in GCA, we profiled the expression of 1209 miRNAs in inflamed TABs and normal TABs. Selected miRNAs were then validated by real-time PCRs and in situ hybridisation (ISH).

RESULTS

MiR-146b-5p, -146a, -155, -150, -21 and -299-5p were significantly more expressed in inflamed TABs from patients with GCA. miRNAs were mainly deregulated at the tissue level because peripheral blood mononuclear cells and polymorphonuclear cells from the three groups of patients and age-matched healthy controls had similar levels of miRNAs. ISH showed that miR-21 was mainly expressed by cells in the medial and intimal layers of inflamed TABs. Patients with TAB-negative GCA had a miRNA profile similar to TAB-negative non-GCA patients.

CONCLUSIONS

MiR-146b-5p, -146a, -21, -150, -155, -299-5p are overexpressed in the presence of inflammation in TABs from patients with GCA.

miR-195 plays a role in steroid resistance of ulcerative colitis by targeting Smad7

An imbalance in pro- and anti-inflammation is an important mechanism of steroid resistance in UC (ulcerative colitis), and miRNAs may participate in this process. The present study aimed to explore whether miRNAs play a role in the steroid resistance of UC by regulating gene expression of the inflammation signal pathway. SS (steroid-sensitive) patients, SR (steroid-resistant) patients and healthy individuals were recruited. In vivo miRNA profiles of serum samples showed that miR-195 was decreased significantly in the SR group compared with the SS group (P<0.05). This result was confirmed by qPCR (quantitative real-time PCR) and miRNA ISH (in situ hybridization) in serum and colon tissue samples. Online software was used to identify Smad7 mRNA as a potential target of miR-195. The direct interaction of miR-195 and Smad7 mRNA was investigated using a biotinylated miR-195 pull-down assay. Overexpression of a miR-195 precursor lowered cellular levels of Smad7 protein; conversely, antagonism of miR-195 enhanced Smad7 translation without disturbing Smad7 mRNA levels. A luciferase reporter assay revealed a repressive effect of miR-195 via a single Smad7 3'-UTR target site, and point mutation of this site prevented miR-195-induced repression of Smad7 translation. Furthermore, increased levels of miR-195 led to a decrease in c-Jun and p65 expression. In contrast, transfection with anti-miR-195 led to increased levels of c-Jun and p65 protein. The decrease in miR-195 led to an increase in Smad7 expression and corresponding up-regulation of p65 and the AP-1 (activator protein 1) pathway, which might explain the mechanism of steroid resistance in UC patients.

Could MicroRNA polymorphisms influence warfarin dosing? A pharmacogenetics study on mir133 genes

MicroRNAs are small single stranded molecules that play a crucial role in regulation of physiological and pathological processes. Recent studies showed that VKORC1 gene contains an highly evolutionary conserved binding site for mir-133. Moreover, in human hepatocytes mir-133 is constitutively co-expressed with VKORC1. Since VKORC1 protein is the target of warfarin treatment, the aim of this study was to verify if genetic variations in MIR133A1, MIR133A2 and MIR133B could contribute to warfarin dose variability. By direct sequencing, we identified 4 SNPs in MIR133A2 gene and 1 SNP in MIR133B gene. Three SNPs in MIR133A2 were in complete linkage disequilibrium and correlated with warfarin dose: indeed, for each SNP, patients carrying the GA or AA genotype required a MWWD significantly higher than the wildtype genotype (P=0.019). We also inferred the haplotypes in MIR133A2 gene. The GC haplotype required a MWWD significantly lower than AT haplotype (P=0.012). The multiple linear regression analysis confirmed that rs45547937 (as tag SNP) in MIR133A2 could be involved in warfarin dosing variability, (P=0.016). These results seem to suggest that also polymorphisms in miRNA precursors may potentially affects drug response variability.

Glucocorticoid inhibits cell proliferation in differentiating osteoblasts by microRNA-199a targeting of WNT signaling

The inhibition of osteoblast proliferation by glucocorticoids (GCs) is very important in the etiology of GC-induced osteoporosis. The mechanisms of this process are still not fully understood. The results of recent studies have indicated an important role for microRNAs in GC-mediated responses in various cellular processes, including cell proliferation and apoptosis. Therefore, we developed the hypothesis that these regulatory molecules might be involved in GC-decreased osteoblast proliferation. Western blotting, quantitative real-time PCR, cell proliferation assays, and luciferase assays were employed to investigate the role of miRNAs in GC-inhibited osteoblast proliferation. microRNA-199a-5p was significantly increased in osteoblasts treated with dexamethasone (Dex). To delineate the role of microRNA-199a-5p, we silenced and overexpressed microRNA-199a-5p in osteoblasts. We found that overexpressing microRNA-199a-5p remarkably increased the inhibition effect of Dex on osteoblast proliferation, and depleting microRNA-199a-5p significantly attenuated Dex-inhibited osteoblast proliferation. Results of mechanistic studies indicated that microRNA-199a-5p inhibited FZD4 and WNT2 expression through a microRNA-199a-5p binding site within the 3'-UTR of FZD4 and WNT2. The post-transcriptional repression of FZD4 and WNT2 were further confirmed by luciferase reporter assay. These results indicated that microRNA-199a-5p may play a significant role in GC-inhibited osteoblast proliferation by regulating the WNT signaling pathway.

Circulating microRNA predicts insensitivity to glucocorticoid therapy in Graves' ophthalmopathy

Glucocorticoid (GC) insensitivity occurs commonly in Graves' ophthalmopathy (GO), and GC therapy is associated with major adverse effects. A reliable and easily accessible biomarker is required to predict the outcome of GC therapy. This study aimed to evaluate the performance of circulating microRNA (miRNA) to predict GC insensitivity in GO patients. A total of 35 consecutive patients were included in this study. A cumulative dose of 4.5 g of methylprednisolone (MP) was administered intravenously for 12 weeks. Pretreatment serum miRNAs from the best- (N = 5) and worst- (N = 4) responding patients were profiled using miScript PCR arrays and validated by quantitative PCR in all patients. We calculated the predictive value of pretreatment assays of serum miRNAs with regard to GC insensitivity. We further investigated the roles of target miRNAs in modulating NF-κB activity and restoring transrepression of an NF-κB reporter by dexamethasone. Nine miRNAs displayed significant differences between responsive and resistant patients by miScript PCR arrays. Validation of the top two miRNAs in all 35 patients confirmed a significantly lower serum level of miR-224-5p (p = 0.0048) in resistant patients. A multivariate logistic regression model identified a composite biomarker combining baseline serum miR-224-5p and TRAb was independently associated with GC response (OR: 2.565, 95 % CI 1.011-6.505, p = 0.047). Receiver operating characteristic (ROC) curves analysis revealed the composite marker combining miR-224-5p and TRAb led to a 91.67 % positive prediction value (PPV) and a 69.56 % negative prediction value (NPV) with regard to GC resistance. Overexpression of miR-224-5p restored transrepression of the NF-κB reporter by dexamethasone under induced resistance, which may be via targeting GSK-3β to increase GR protein level. Our study demonstrated baseline serum miR-224-5p was associated with GC sensitivity in GO and in vitro overexpression of miR-224-5p restored GC sensitivity in a resistant cell model. A parameter combined serum miR-224-5p and TRAb could effectively predict GC sensitivity in GO patients.

Small and Long Regulatory RNAs in the Immune System and Immune Diseases

Cellular differentiation is regulated on the level of gene expression, and it is known that dysregulation of gene expression can lead to deficiencies in differentiation that contribute to a variety of diseases, particularly of the immune system. Until recently, it was thought that the dysregulation was governed by changes in the binding or activity of a class of proteins called transcription factors. However, the discovery of micro-RNAs and recent descriptions of long non-coding RNAs (lncRNAs) have given enormous momentum to a whole new field of biology: the regulatory RNAs. In this review, we describe these two classes of regulatory RNAs and summarize what is known about how they regulate aspects of the adaptive and innate immune systems. Finally, we describe what is known about the involvement of micro-RNAs and lncRNAs in three different autoimmune diseases (celiac disease, inflammatory bowel disease, and multiple sclerosis).

Targeting glucocorticoid side effects: selective glucocorticoid receptor modulator or glucocorticoid-induced leucine zipper? A perspective

Glucocorticoids (GCs) are steroid hormones that are necessary for life and important in health and disease. They regulate crucial homeostatic functions, including metabolism, cell growth, and development. Although GCs are regulated by circadian rhythm, increased production is associated with stress. Synthetic GCs are a valuable resource for anti-inflammatory and immunosuppressive therapy. Natural and synthetic GCs transduce signals mainly through GC receptor (GR) activation. Extensive research has explored the downstream targets of the GR, and optimization of GC therapy has required collaborative efforts. One highly promising approach involves new dissociative GR modulators. Because transrepression and transactivation of GR genes induce beneficial and adverse effects, respectively, this approach favors transrepression. Another approach involves the use of GC-dependent genes to generate proteins to mediate therapeutic GC effects. In a third approach, drug discovery is used to identify agents that selectively target GR isoforms to obtain differential gene transcription and effects. In this review, we focus on mechanisms of GR function compatible with the use of dissociative drugs. We highlight GC-induced leucine zipper (GILZ), a gene cloned in our laboratory, as a mediator of GC anti-inflammatory and immunosuppressive effects, to outline our perspective on the future of GC therapy.

Linking immunity, epigenetics, and cancer in inflammatory bowel disease

Most of what is known about the pathogenesis of inflammatory bowel disease (IBD) pertains to complex interplay between host genetics, immunity, and environmental factors. Epigenetic modifications play pivotal roles in intestinal immunity and mucosal homeostasis as well as mediating gene-environment interactions. In this article, we provide a historical account of epigenetic research either directly related or pertinent to the pathogenesis and management of IBD. We further collate emerging evidence supporting roles for epigenetic mechanisms in relevant aspects of IBD biology, including deregulated immunity, host-pathogen recognition and mucosal integrity. Finally, we highlight key epigenetic mechanisms that link chronic inflammation to specific IBD comorbidities, including colitis-associated cancer and discuss their potential utility as novel biomarkers or pharmacologic targets in IBD therapy.

[Potential relevance of microRNAs in the diagnostics of inflammatory bowel diseases]

Inflammatory bowel diseases are chronic inflammatory disorders characterized by relapses and remissions. Several factors have been suggested to participate in their development, although their detailed pathogenesis still remains largely unknown. MicroRNAs are single strained, non-coding RNAs, consisting of 18-25 nucleotides that regulate gene expression at the posttranscriptional level. Aberrant expression of microRNAs has been found in several malignant tumors. Recently the role of microRNAs in the pathogenesis of inflammatory-autoimmune disorders (such as inflammatory bowel disease) is being intensively investigated. Beside their pathogenic roles, microRNAs can also be exploited as diagnostic markers, especially in cases where the interpretation of histological data is difficult. In this review the authors discuss recent findings in the field of microRNAs in the diagnosis and pathogenesis of inflammatory bowel diseases.

Unmet needs in the treatment of autoimmunity: from aspirin to stem cells

As rheumatologic diseases became understood to be autoimmune in nature, the drugs used to treat this group of conditions has evolved from herbal or plant derived anti-inflammatory agents, such as salicylates, quinine and colchicine to the many recently approved biological response modifiers. These new drugs, especially the anti-tumor necrosis factor agents, have shown remarkable efficacy in autoimmune diseases, and there are new agents under investigation that will provide additional treatment options. In between, the world was introduced to cortisone and all of its derivatives, as chemical synthesis led to better, more efficacious drugs with lesser side effects. Disease modifying anti-rheumatic agents have actually been around since the first half of the 20th century, but only began to be used in the treatment of autoimmune diseases in the 1970s and 1980s. One advantage is that they have been invaluable in their ability to offer "steroid sparing" to decrease the adverse effects of steroids. Research over the past decade has resulted in a new class of drugs that influence cytokine regulatory pathways such as the Janus associated kinase inhibitors. The promise of personalized medicine now permeates current research into new pharmacological agents for the treatment of autoimmune disease. The new appreciation for the gene-environment interaction in the pathogenesis of most diseases especially those as heterogeneous as autoimmune diseases, has led to our focus on targeted therapies. Add to that the new knowledge of epigenetics and how changes in DNA and histone structure affect expression of genes that can play a role in immune signaling, and we now have a new exciting frontier for cutting edge drug development. The history of treatment of autoimmune diseases is really only a little over a century, but so much has changed, leading to increasing lifespans and improved quality of life of those who suffer from these ailments.