miR-155 In Response Research Articles

Differential Expression of miR-146 and miR-155 in Active and Latent Tuberculosis Infection.

Tuberculosis (TB) is one of the leading causes of death worldwide. Besides, one-third of the world population is infected with Mycobacterium tuberculosis (MTB) while staying clinically asymptomatic; the situation is called latent TB infection (LTBI). MiR-21, miR-31, miR-146a, and miR-155 play an important role in many immune and inflammatory pathways. In the present study the expression levels of MiR-21, miR-31, miR-146a, and miR-155 in peripheral blood mononuclear cells (PBMCs) from patients with active TB, latently infected individuals (LTBI), and healthy controls (HC) were investigated. Participants were recruited at the Bouali Hospital, Zahedan University of Medical Sciences, Zahedan, Iran from 2010 to 2011. PBMCs were stimulated with PPD before RNA extraction. TaqMan RT-qPCR assay was used to analyze the expression levels of miRNAs. The results indicated no significant differences in the expression of miR-21 and miR-31 between different groups; however, in patients with active TB, the expression of miR-21 (P=0.03) and miR-31 (P=0.04) were significantly increased after stimulation with PPD compared to the unstimulated condition. The expression of miR-146 in response to PPD in both LTBI (P=0.02) and TB (P=0.03) groups compared to the HC group was increased. No significant differences were found in the expression level of miR-155 in response to PPD between LTBI and HC groups. However, the fold change was significantly higher in the TB group in comparison with the HC (P=0.03) and LTBI (P=0.05) groups. The results confirm the main role of miR-146 and miR-155 in TB infection and suggest a role for miR-146 and miR-155 as infection and activation markers in tuberculosis infection, respectively.

Phase II/1b Trial of Ibrutinib Plus Prednisone and Rituximab Induction Followed By Venetoclax Plus Ibrutinib Maintenance in Newly Diagnosed High-Risk Chronic Lymphocytic Leukemia

Introduction: Therapy options for chronic lymphocytic leukemia (CLL) are rapidly changing with the approval of ibrutinib, an irreversible Bruton's tyrosine kinase inhibitor, and venetoclax, a Bcl2 inhibitor. In the RESONATE studies, ibrutinib showed significant improvements in overall response rates (ORR), progression-free-survival (PFS), and overall survival (OS). Nonetheless, complete response (CR) rates were only about 4%.During the first few weeks of treatment, ibrutinib will mobilize CLL cells from tissue sites into peripheral blood. Rituximab, a chimeric monoclonal CD20 antibody, when used with ibrutinib, has shown to immediately clear CLL from the blood with durable responses but with CR's of only 8%.Venetoclax is approved for relapsed or refractory CLL with 17p deletion. In a phase 2 study, at a median follow-up of 12.1 months, the ORR was ~79%, but with only 16% CR's. Amongst the 45 patients of whom minimal residual disease (MRD) was assessed, 24 were negative for MRD.In vitro studies have shown that nurse-like cells (NLCs) will protect CLL cells against spontaneous apoptosis by producing chemokines and interleukins such as SDF1, suggestive of a mechanism of ibrutinib resistance. SDF1 was shown to bind to its receptor CXCR4 located on CLL cells and activate a signal transduction pathway that would reduce spontaneous apoptosis. Dexamethasone was found to decrease NLC viability. This suggests that a combined therapy of ibrutinib plus steroids along with rituximab and venetoclax may be necessary to achieve deeper CR's in high-risk CLL.In addition, CLL with overexpression of exosome miR-155 is associated with a poor response to chemoimmunotherapy. In prior preclinical studies, exosome miR-150 and miR-155 have been shown to increase with BCR activation via α-IgM stimulation. We hope that via next generation microRNA sequencing from our patients' CLL plasma cells we will observe a decrease in the levels of exosome miR-150 and miR-155 in response to inhibition of BCR-pathway by ibrutinib as seen in preclinical studies.Methods: Patients with newly diagnosed high-risk CLL per FISH studies will be enrolled. Ibrutinib will be administered orally 420 mg daily, rituximab will be dosed at 375 mg/m2 intravenously on days 1, 8, 15, 22 of cycle 1 and on day 1 for cycle 2-6. Prednisone will be administered as 10 mg one week on, one week off per cycle. Each cycle will last 28 days. After 6 cycles, if patients have MRD, venetoclax will be added in on a weekly schedule with weekly ramp up from 20mg to 50mg, 100mg, and 200mg for a total duration of 6 months plus ibrutinib at 420mg as maintenance until disease progression or drug intolerance. There is the option to reintroduce venetoclax, prednisone, or rituximab if patients progress during maintenance.Results: The primary objectives of this study are to evaluate safety and MRD negative CR rates based on IWG-CLL criteria. For the evaluation of safety, the proportions of the 29 subjects with any adverse events, each specific adverse event, and study-related adverse events will be reported along with the 95% confidence intervals. The proportion of the 29 subjects who demonstrate a MRD negative CR will be reported along with the 95% confidence interval. A sample size of 29 will produce a two-sided 95% confidence interval with a width≤ 0.380.In addition, Kaplan-Meier method will be performed to evaluate time to first MRD negativity (TTMN), time to first relapse (TTFR), PFS and OS, respectively. Based on the Kaplan-Meier curve, the median time to TTMN, TTFR, PFS and OS, respectively, will be reported along with the 95% confidence interval if it exists. Correlation coefficients will be derived to describe the relationship between continuous endpoints and Kendall's tau will be derived to describe the relationship between categorical endpoints.There is no planned interim analysis for the CR rate. However, at any time point if an excessive number of adverse events are observed, the study will be terminated.Conclusion: In this Phase IB/II clinical trial, we seek to observe prolonged response rates of ibrutinib via inhibiting NLC's by adding prednisone. Also, we anticipate that rituximab will further amplify the CR's. For maintenance therapy, we hope that by combining venetoclax with ibrutinib in high-risk CLL patients who were unable to achieve negative MRD's, we will be able to induce deeper remissions. [Display omitted] DisclosuresPersky:Genentech: Consultancy; MorphoSys: Other: Independent Data Monitoring Committee member ; Verastem: Consultancy; Spectrum Pharmaceuticals: Research Funding.

MicroRNA-155 Promotes Myocardial Infarction-Induced Apoptosis by Targeting RNA-Binding Protein QKI.

Acute myocardial infarction (AMI) is the leading cause of sudden death worldwide. MicroRNA-155 (miR-155) has been reported to target antiapoptotic genes in various diseases models, but the functional role of miR-155 in response to MI injury needs further investigations. This study investigated the role of miR-155 in myocardial ischemia injury. TUNEL and flow cytometry were performed to measure cell apoptosis. Western blot analysis was employed to detect protein expressions of Bcl-2, XIAP, Bax, and caspase-3. qRT-PCR was used to quantify miRNA levels. We showed that miR-155 was dynamically elevated in murine hearts subjected to MI and in neonatal rat ventricular cardiomyocyte (NRVM) injury induced by hydrogen peroxide (H2O2). In response to H2O2, the silencing of miR-155 using AMO-155 (antisense inhibitor oligodeoxyribonucleotides) significantly increased cell viability and reduced cell apoptosis. Moreover, AMO-155 reversed the H2O2-induced downregulation of Bcl-2 and XIAP and upregulation of Bax and cleaved-caspase-3. Further study revealed that AMO-155 resulted in a decrease of H2O2-induced JC-1-labelled monomeric cell number. In addition, AMO-155 markedly decreased infarct size, ameliorated impaired cardiac function, and significantly reduced apoptotic cell percentages in MI mice heart. The RNA-binding protein Quaking (QKI) was predicted as a target gene of miR-155 through bioinformatic analysis, and AMO-155 attenuated the downregulation of QKI in H2O2-treated cardiomyocytes and MI mice heart. Knockdown of QKI by siRNA abolished the antiapoptotic effects of AMO-155. Taken together, miR-155 is upregulated in the MI heart and NRVMs in response to H2O2 stress, and downregulating of miR-155 protects cardiomyocytes against apoptosis. Mechanistically, it is probably due to the repression of QKI signaling pathway.

Micro-RNA-155 is induced by K-Ras oncogenic signal and promotes ROS stress in pancreatic cancer.

The oncogenic K-Ras can transform various mammalian cells and plays a critical role in development of pancreatic cancer. MicroRNAs (miRNA) have been shown to contribute to tumorigenic progression. However, the nature of miRNAs involved in K-Ras transformation remains to be investigated. Here, by using microarray we identified miR-155 as the most upregulated miRNA after both acute and prolonged activation of K-Ras in a doxycyline-inducible system. Pharmacological inhibition of MAPK and NF-κB pathway blocked the induction of miR-155 in response to K-Ras activation. Overexpression of miR-155 caused inhibition of Foxo3a, leading to decrease of major antioxidants including SOD2 and catalase, and enhanced pancreatic cell proliferation induced by ROS generation. Importantly, correlations of K-Ras, miR-155 and Foxo3a were also validated in human pancreatic cancer tissues. Therefore, we propose that miR-155 plays an important role in oncogenic K-Ras transformation mediated by cellular redox regulation.

Decreased expression of miR-146a and miR-155 contributes to an abnormal Treg phenotype in patients with rheumatoid arthritis

ObjectivesMicroRNAs (miRNAs) have been implicated in the pathogenesis of autoimmune diseases, not least for their critical role in the regulation of regulatory T cell (Treg) function. Deregulated expression of miR-146a...

The Role of Ets2 Transcription Factor in the Induction of MicroRNA-155 (miR-155) by Lipopolysaccharide and Its Targeting by Interleukin-10

MicroRNA-155 (miR-155) is highly expressed in many cancers such as B cell lymphomas and myeloid leukemia and inflammatory disorders such as rheumatoid arthritis, atopic dermatitis, and multiple sclerosis. The role of miR-155 as both a promoter of inflammation and an oncogenic agent provides a clear need for miR-155 itself to be stringently regulated. We therefore investigated the transcriptional regulation of miR-155 in response to the respective pro- and anti-inflammatory mediators LPS and IL-10. Bioinformatic analysis revealed Ets binding sites on the miR-155 promoter, and we found that Ets2 is critical for miR-155 induction by LPS. Truncation and mutational analysis of the miR-155 promoter confirmed the role of the Ets2 binding site proximal to the transcription start site for LPS responsiveness. We observed increased binding of Ets2 to the miR-155 promoter and Ets2 deficient mice displayed decreased induction of miR-155 in response to LPS. IL-10 inhibited the induction of Ets2 mRNA and protein by LPS, thereby decreasing Ets2 function on the pri-155 promoter. We have thus identified Ets2 as a key novel regulator in both the positive and negative control of miR-155 in the inflammatory response.

LC-MS/MS-based shotgun proteomics identified the targets of arthritis-related microRNA

microRNAs (miRNAs), which are class of post-transcriptional regulators such as short 19 to 23-nucleotide non-coding RNAs, complementarily bind seed sequences in the 3'-untranslational region of multiple target mRNAs, resulting in their suppression of translation or degradation [1]. In the former case, since the mRNA expression of the targets does not any change, transcriptomics approach, such as expression array, cannot identify the targets. Recent studies shed light on the fine-tuning mechanism of miRNAs in myriad biological processes including development [2], tumorigenesis [3] and inflammation [4]. We have identified enhancement of mir-146a expression in rheumatoid arthritis synoviocyte and macrophages [5], whilst suppression of them in osteoarthritis [6]. Another group also have identified the enhancement of mir-146a and mir-155 in response to bacterial pathogen such as lipopolysaccaride [7]. Recently, mice lacking of mir-155 are resistant to collagen-induced arthritis (CIA) [8], whilst administration of mir-146a complexed with aterocollagen into joint attenuates pathological condition of CIA [9]. These results indicate that mir-146a and mir-155 plays an important role for developing arthritis and inflammation. However, the targets of both two miRNAs and their molecular mechanisms are not still fully identified. In this study, in order to identify the targets of them in translational level, we established gain of function models using adenovirus- and CMV promoter-mediated overexpression in several culture models and performed liquid chromatography-tandem mass spectrometry-based shotgun proteomics in these models.

Glucocorticoids inhibit lipopolysaccharide-mediated inflammatory response by downregulating microRNA-155: a novel anti-inflammation mechanism

Glucocorticoids (GCs) are among the most widely used and effective therapies for many chronic inflammatory diseases. Although attempts have been made to identify important protein-coding genes and pathways involved in the anti-inflammatory effect of GCs, knowledge of genomic aberrations associated with noncoding genes, such as micro-RNAs (miRNAs), and their contributions is relatively limited. In this study, a systematic screening of the miRNA expression profile by microarray showed that GCs inhibited the expression of miR-155 in lipopolysaccharide (LPS)-induced macrophage inflammatory responses. Overexpression of miR-155 markedly reversed the suppressive action of GCs, whereas inhibition of miR-155 exhibited an effect similar to that of GCs on LPS-treated RAW264.7 cells, indicating miR-155 to be a functional regulator in the anti-inflammatory effect of GCs. Furthermore, GCs inhibited miR-155 expression in a GC receptor- and NF-κB-dependent manner. Bioinformatics analysis and luciferase assay revealed that the NF-κB binding site located in the promoter region of the B-cell integration cluster was important in mediating the GC-driven suppression of miR-155 in response to LPS stimulation. In addition, the combination of treatment with GCs and inhibition of miR-155 enhanced the anti-inflammatory effect of GCs on LPS-stimulated RAW264.7 cells. Therefore, we identify miR-155 to be a novel target through which GCs exert their anti-inflammatory effect on the LPS-induced macrophage inflammatory response. These findings may provide a basic rationale for new approaches in the effort to develop anti-inflammatory therapeutics.

Abstract 17373: MicroRNA-155 Over-expression Inhibits Angiogenesis Of Lin - /cd34 + Cells From Human CAD Patients and HUVECs

Introduction: In the cellular hypothesis of atherosclerosis, bone marrow (BM) derived EPCs contribute to vascular repair and regeneration, and defects in number and/or function of EPCs may contribute to the progression of atherosclerosis and coronary artery disease (CAD). Autologous stem cell therapy for CAD requires functionally competent EPCs. Micro-RNAs (miRs) have been implicated in the regulation of angiogenesis; miR-155 is activated by inflammatory cytokines. Hypothesis: Dysregulated expression of miR-155 in response to an inflammatory environment within the BM of CAD patients causes functional defects in BM-derived EPCs that promote CAD progression and impairment of autologous stem cell therapy. Objective: To quantify the level of miR-155 in EPCs from CAD patients and functionally characterize the effects of miR 155 over-expression on the angiogenic potential of Lin - /CD34 + cells and HUVECs. Methods: BM was collected from 5 CAD, 4 non-CAD patients and healthy volunteers; Lin - /CD34 + cells were isolated and subjected to microarray and micro-RNA profiling. HUVECs were transfected with pre and anti-miRs of miR-155. HUVEC tube formation, proliferation and cell death were quantified. Protein and RNA were quantified by western blot and RT-PCR. Results: Microarray and RT-PCR confirmed >5-fold up regulation of miR-155 in Lin - /CD34 + cells of CAD patients compared with non-CAD (p<0.05). MiR-155 knockdown in HUVECs increased HIF1alpha and CCND1 protein as measured by western blot (p<0.05). MiR-155 over-expression using precursor molecules significantly inhibited tube formation and cell proliferation of HUVECs (both p<0.01). LDH assay revealed an increase in cell death of HUVECs transfected with pre-miR-155 (p<0.05). The results are consistent with other studies showing that miR-155 regulates multiple biological processes including cell differentiation, survival, and cell migration and extrapolate this to suppression of angiogenesis. Conclusion: The expression of miR-155 is markedly increased in CD34+/Lin- EPCs from patients with CAD. miR-155 over expression represses angiogenesis and may drive disease progression. Neutralization of miR-155 over-expression in EPCs is predicted to improve autologous stem cell therapy for CAD.

IL-10 Inhibits miR-155 Induction by Toll-like Receptors

IL-10 is a potent anti-inflammatory cytokine that is crucial for down-regulating pro-inflammatory genes, which are induced by Toll-like receptor (TLR) signaling. In this study, we have examined whether modulation of microRNAs plays a role in the inhibitory effect of IL-10 on TLR4 signaling. Analyzing microRNAs known to be induced by TLR4, we found that IL-10 could inhibit the expression of miR-155 in response to lipopolysaccharide but had no effect on miR-21 or miR-146a. IL-10 inhibited miR-155 transcription from the BIC gene in a STAT3-dependent manner. This inhibitory effect of IL-10 on miR-155 led to an increase in the expression of the miR-155 target, SHIP1. This is the first example of IL-10 playing a role in microRNA function and suggests that through its inhibitory effect on miR-155, IL-10 has the ability to promote anti-inflammatory gene expression.

The anti-inflammatory cytokine IL-10 inhibits miR-155 in response to Toll-like Receptor signalling

The anti-inflammatory cytokine IL-10 inhibits miR-155 in response to Toll-like Receptor signalling

MicroRNA-155 is induced during the macrophage inflammatory response

The mammalian inflammatory response to infection involves the induction of several hundred genes, a process that must be carefully regulated to achieve pathogen clearance and prevent the consequences of unregulated expression, such as cancer. Recently, microRNAs (miRNAs) have emerged as a class of gene expression regulators that has also been linked to cancer. However, the relationship between inflammation, innate immunity, and miRNA expression is just beginning to be explored. In the present study, we use microarray technology to identify miRNAs induced in primary murine macrophages after exposure to polyriboinosinic:polyribocytidylic acid or the cytokine IFN-beta. miR-155 was the only miRNA of those tested that was substantially up-regulated by both stimuli. It also was induced by several Toll-like receptor ligands through myeloid differentiation factor 88- or TRIF-dependent pathways, whereas up-regulation by IFNs was shown to involve TNF-alpha autocrine signaling. Pharmacological inhibition of the kinase JNK blocked induction of miR-155 in response to either polyriboinosinic:polyribocytidylic acid or TNF-alpha, suggesting that miR-155-inducing signals use the JNK pathway. Together, these findings characterize miR-155 as a common target of a broad range of inflammatory mediators. Importantly, because miR-155 is known to function as an oncogene, these observations identify a potential link between inflammation and cancer.