Increased miR‐223 expression in T cells from patients with rheumatoid arthritis leads to decreased insulin‐like growth factor‐1‐mediated interleukin‐10 production

We hypothesized that the aberrant expression of microRNAs (miRNAs) in rheumatoid arthritis (RA) T cells was involved in the pathogenesis of RA. The expression profile of 270 human miRNAs in T cells from the first five RA patients and five controls were analysed by real‐time polymerase chain reaction. Twelve miRNAs exhibited potentially aberrant expression in RA T cells compared to normal T cells. After validation with another 22 RA patients and 19 controls, miR‐223 and miR‐34b were over‐expressed in RA T cells. The expression levels of miR‐223 were correlated positively with the titre of rheumatoid factor (RF) in RA patients. Transfection of Jurkat cells with miR‐223 mimic suppressed insulin‐like growth factor‐1 receptor (IGF‐1R) and transfection with miR‐34b mimic suppressed cAMP response element binding protein (CREB) protein expression by Western blotting. The protein expression of IGF‐1R but not CREB was decreased in RA T cells. The addition of recombinant IGF‐1‐stimulated interleukin (IL)‐10 production by activated normal T cells, but not RA T cells. The transfection of miR‐223 mimic impaired IGF‐1‐mediated IL‐10 production in activated normal T cells. The expression levels of SCD5, targeted by miR‐34b, were decreased in RA T cells after microarray analysis. In conclusion, both miR‐223 and miR‐34b were over‐expressed in RA T cells, but only the miR‐223 expression levels were correlated positively with RF titre in RA patients. Functionally, the increased miR‐223 expression could impair the IGF‐1‐mediated IL‐10 production in activated RA T cells in vivo, which might contribute to the imbalance between proinflammatory and anti‐inflammatory cytokines.     

Localization‐ and mutation‐dependent microRNA (miRNA) expression signatures in gastrointestinal stromal tumours (GISTs), with a cluster of co‐expressed miRNAs located at 14q32.31

The molecular biology and clinical behaviour of gastrointestinal stromal tumours (GISTs) are associated with their anatomical localization (stomach or intestine), and also with the mutation status of the receptor tyrosine kinases KIT and PDGFRA. Twelve GISTs were evaluated for differential miRNA expression signatures by use of microarrays representing 734 human miRNAs. Thirty‐two miRNAs were found to be differentially expressed according to localization and mutation status. Differential expression was further analysed and confirmed for four miRNAs (miR‐132, miR‐221, miR‐222, and miR‐504) by qRT‐PCR in 49 additional GISTs. Differentially expressed miRNAs were functionally mapped to KIT/PDGFRA signalling and G1/S‐phase transition of the cell cycle, revealing 22 predicted miRNA/mRNA interactions for ten gene targets from KIT/PDGFRA signalling, and 12 interactions for 12 gene targets of G1/S‐phase transition. Moreover, the expression of 44 miRNAs clustered in a genetically imprinted region at 14q32.31 was found to be strongly correlated in the microarray analysis. This was confirmed for two selected miRNAs (miR‐134 and miR‐370) from the 14q32.31 cluster by qRT‐PCR in 49 additional GISTs, and the expression of these two miRNAs was significantly lower in GISTs with 14q loss, and also in GISTs with tumour progress. miRNA profiling may prove to be a key determinant of the biology and clinical features of GISTs Copyright © 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

MiR‐183 delivery attenuates murine lupus nephritis‐related injuries via targeting mTOR

MicroRNAs (miRNAs) play a vital role in the occurrence and development of many human diseases, including systemic lupus erythematosus (SLE). SLE is an autoimmune disease characterized by the production of autoantibodies against nuclear antigens and multiorgan involvement. Study of miRNAs involved in SLE provides new insights into the pathogenesis of SLE and might lead to the identification of new therapeutic interventions. The aim of this study was to investigate the effect of miR‐183 injection on the progression of SLE by using MRL/lpr mouse model. The expression levels of miR‐183 and mTOR mRNA were detected by quantitative real‐time PCR assay. The effect of miR‐183 on the course of spontaneous disease progression in the MRL/lpr mice was examined by intraperitoneal injection of miR‐183 into mice and followed by monitoring lifespan, anti‐dsDNA antibody levels, urinary albumin levels, blood urea nitrogen (BUN) levels, and Tregs and Th17 cell population. We found that miR‐183 injection resulted in reduction of anti‐DNA antibody and immune complex component levels, restoration of Tregs and Th17 cell population and prolongation of survival. Our findings suggest that miR‐183 injection may serve as an effective therapeutic treatment for delaying or easing pathologic features of SLE.     

Immunopathogenesis of systemic lupus erythematosus and rheumatoid arthritis: the role of aberrant expression of non‐coding RNAs in T cells

Non‐coding RNAs (ncRNAs), including microRNAs (miRNAs) and long non‐coding RNAs (lncRNAs), are RNA molecules that do not translate into protein. Both miRNAs and lncRNAs are known to regulate gene expression and to play an essential role in T cell differentiation and function. Both systemic lupus erythematosus (SLE), a prototypic systemic autoimmune disease, and rheumatoid arthritis (RA), a representative disease of inflammatory arthritis, are characterized by a complex dysfunction in the innate and adaptive immunity. T cells play a central role in cell‐mediated immune response and multiple defects in T cells from patients with SLE and RA have been observed. Abnormality in T cell signalling, cytokine and chemokine production, T cell activation and apoptosis, T cell differentiation and DNA methylation that are associated closely with the aberrant expression of a number of miRNAs and lncRNAs have been implicated in the immunopathogenesis of SLE and RA. This review aims to provide an overview of the current state of research on the abnormal expression of miRNAs and lncRNAs in T cells and their roles in the immunopathogenesis of SLE and RA. In addition, by comparing the differences in aberrant expression of miRNAs and lncRNAs in T cells between patients with SLE and RA, controversial areas are highlighted that warrant further investigation.     

MicroRNA‐21 expression in neonatal blood associated with antenatal immunoglobulin E production and development of allergic rhinitis

Background The prevalence of allergic diseases has increased in the past decades. It is unknown whether expression of certain microRNAs (miRNAs) in neonatal leucocytes is correlated to IgE production and/or allergic diseases. Objective This study investigated the association of miRNA expression in neonatal leucocytes with cord blood IgE (CBIgE) elevation and development of allergic disease. Methods We screened for the expression of a panel of 157 miRNAs in mononuclear leucocytes from human umbilical cord blood (CB) samples with elevated CBIgE and tracked the association of down‐regulated miRNA expression to the miRNA‐targeted gene expression and to children with allergic rhinitis (AR). Results Among the initial screen of 10 CB samples with elevated CBIgE, expression of eight of the 157 miRNAs was low. Of these eight down‐expressed miRNAs, three remained down‐regulation in a validation with other 20 CB samples, and two of the three miRNAs, miR‐21 and miR‐126, were significantly lower in monocytes from AR children. Further analysis of mRNA expression of the miR‐21‐targeted genes identified that TGFBR2 expression on monocytes was significantly up‐regulated in CB with elevated CBIgE, and in AR patients. Transfection of miR‐21 precursor into monocytes from patients with AR increased miR‐21 expression and decreased TGFBR2 expression. Conclusion This study demonstrated the first in the literature that lower miR‐21 expression in CB and increased TGFBR2 expression is associated with antenatal IgE production and development of AR. Cite this as: R.‐F. Chen, H.‐C. Huang, C.‐Y. Ou, T.‐Y. Hsu, H. Chuang, J.‐C. Chang, L. Wang, H.‐C. Kuo and K. D. Yang, Clinical & Experimental Allergy, 2010 (40) 1482–1490.     

Exosomal miR‐24‐3p impedes T‐cell function by targeting FGF11 and serves as a potential prognostic biomarker for nasopharyngeal carcinoma

Recent studies have shown that extracellular microRNAs are not only potential biomarkers but are also involved in cell interactions to regulate the intercommunication between cancer cells and their microenvironments in various types of malignancies. In this study, we isolated exosomes from nasopharyngeal carcinoma (NPC) cell lines and patient sera (T‐EXOs), or control NP69 cells and healthy donor sera (HD‐EXOs). We found that miR‐24‐3p was markedly enriched in T‐EXOs as compared with HD‐EXOs; the serum exosomal miR‐24‐3p level was correlated with worse disease‐free survival of patients (p < 0.05). Knockdown of exosomal miR‐24‐3p (miR‐24‐3p‐sponge‐T‐EXOs) by a sponge RNA targeting miR‐24‐3p restored the T‐EXO‐mediated (control‐sponge‐T‐EXO) inhibition of T‐cell proliferation and Th1 and Th17 differentiation, and the induction of regulatory T cells (Tregs). Mechanistic analyses revealed that administration of exosomal miR‐24‐3p increased P‐ERK, P‐STAT1 and P‐STAT3 expression while decreasing P‐STAT5 expression during T‐cell proliferation and differentiation. Moreover, by in vivo and in vitro assessments, we found FGF11 to be a direct target of miR‐24‐3p. However, both miR‐24‐3p‐sponge‐T‐EXOs and T‐EXOs (control‐sponge‐T‐EXOs) impeded proliferation and Th1 and Th17 differentiation, but induced Treg differentiation, of lenti‐shFGF11‐transfected T cells. The levels of phosphorylated ERK and STAT proteins were different in lenti‐ScshRNA‐transfected T cells and lenti‐shFGF11‐transfected T cells following administration of miR‐24‐3p‐sponge‐T‐EXO. Interestingly, tumour FGF11 expression was positively correlated with the number of CD4⁺ and CD8⁺ T cells in vivo, and predicted favourable patient DFS (p < 0.05). Additionally, hypoxia increased cellular and exosomal miR‐24‐3p levels and enhanced the inhibitory effect of T‐EXO on T‐cell proliferation and differentiation. Collectively, our findings suggest that exosomal miR‐24‐3p is involved in tumour pathogenesis by mediating T‐cell suppression via repression of FGF11, and may serve as a potential prognostic biomarker in NPC. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Combined miRNA profiling and proteomics demonstrates that different miRNAs target a common set of proteins to promote colorectal cancer metastasis

The process of liver colonization in colorectal cancer remains poorly characterized. Here, we addressed the role of microRNA (miRNA ) dysregulation in metastasis. We first compared miRNA expression profiles between colorectal cancer cell lines with different metastatic properties and then identified target proteins of the dysregulated miRNAs to establish their functions and prognostic value. We found that 38 miRNAs were differentially expressed between highly metastatic (KM12SM /SW620 ) and poorly metastatic (KM12C /SW480 ) cancer cell lines. After initial validation, we determined that three miRNAs (miR ‐424‐3p, ?503, and ?1292) were overexpressed in metastatic colorectal cancer cell lines and human samples. Stable transduction of non‐metastatic cells with each of the three miRNAs promoted metastatic properties in culture and increased liver colonization in vivo . Moreover, miR ‐424‐3p and miR ‐1292 were associated with poor prognosis in human patients. A quantitative proteomic analysis of colorectal cancer cells transfected with miR ‐424‐3p, miR ‐503, or miR ‐1292 identified alterations in 149, 129, or 121 proteins, respectively, with an extensive overlap of the target proteins of the three miRNAs . Importantly, down‐regulation of two of these shared target proteins, CKB and UBA2 , increased cell adhesion and proliferation in colorectal cancer cells. The capacity of distinct miRNAs to regulate the same mRNAs boosts the capacity of miRNAs to regulate cancer metastasis and underscores the necessity of targeting multiple miRNAs for effective cancer therapy. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

MicroRNAs regulate T‐cell production of interleukin‐9 and identify hypoxia‐inducible factor‐2α as an important regulator of T helper 9 and regulatory T‐cell differentiation

MicroRNAs (miRNAs) regulate many aspects of helper T cell (Th) development and function. Here we found that they are required for the suppression of interleukin‐9 (IL‐9) expression in Th9 cells and other Th subsets. Two highly related miRNAs (miR‐15b and miR‐16) that we previously found to play an important role in regulatory T (Treg) cell differentiation were capable of suppressing IL‐9 expression when they were over‐expressed in Th9 cells. We used these miRNAs as tools to identify novel regulators of IL‐9 expression and found that they could regulate the expression of Epas1, which encodes hypoxia‐inducible factor (HIF)‐2α. HIF proteins regulate metabolic pathway usage that is important in determining appropriate Th differentiation. The related protein, HIF‐1α enhances Th17 differentiation and inhibits Treg cell differentiation. Here we found that HIF‐2α was required for IL‐9 expression in Th9 cells, but its expression was not sufficient in other Th subsets. Furthermore, HIF‐2α suppressed Treg cell differentiation like HIF‐1α, demonstrating both similar and distinct roles of the HIF proteins in Th differentiation and adding a further dimension to their function. Ironically, even though miR‐15b and miR‐16 suppressed HIF‐2α expression in Treg cells, inhibiting their function in Treg cells did not lead to an increase in IL‐9 expression. Therefore, the physiologically relevant miRNAs that regulate IL‐9 expression in Treg cells and other subsets remain unknown. Nevertheless, the analysis of miR‐15b and miR‐16 function led to the discovery of the importance of HIF‐2α so this work demonstrated the utility of studying miRNA function to identify novel regulatory pathways in helper T‐cell development.     

MicroRNA‐664a‐5p promotes neuronal differentiation of SH‐SY5Y cells

MicroRNAs (miRNAs) belong to a class of small noncoding RNAs that play important roles in the translational regulation of gene expression. A number of miRNAs are known to act as key regulators of diverse processes such as neuronal differentiation. In this study, we have attempted to identify novel miRNAs related to neuronal differentiation via microarray analysis in the human neuronal differentiation model neuroblastoma SH‐SY5Y cells. We identified 15 up‐regulated and eight down‐regulated miRNAs in SH‐SY5Y cells treated with all‐trans retinoic acid to induce differentiation. We further showed that one of the up‐regulated miRNAs, miR‐664a‐5p, promoted neuronal differentiation of SH‐SY5Y cells. These findings enhance our understanding of the miRNAs involved in the process of neurogenesis and, in particular, highlight an important role of miR‐664a‐5p in SH‐SY5Y cell neuronal differentiation. Further studies will be required to confirm the function of miR‐664‐5p in neuronal development and disease and to identify its relevant target genes.