miR-10b-5p is a novel Th17 regulator present in Th17 cells from ankylosing spondylitis

MicroRNA implications in the etiopathogenesis of ankylosing spondylitis

Ankylosing spondylitis (AS) is a chronic immune-mediated inflammatory disease that affects both axial and peripheral skeletons as well as soft tissues. Recent investigations offer that disease pathogenesis is ascribed to a complex interplay of genetic, environmental, and immunological factors. Until now, there is no appropriate method for early diagnosis of AS and the successful available therapy for AS patients stay largely undefined. MicroRNAs (miRNAs), endogenous small noncoding RNAs controlling the functions of target mRNAs and cellular processes, are present in human plasma in a stable form and have appeared as possible biomarkers for activity, pathogenesis, and prognosis of the disease. In the present review, we have tried to summarize the recent findings related to miRNAs in AS development and discuss the possible utilization of these molecules as prognostic biomarkers or important therapeutic strategies for AS. Further examinations are needed to determine the unique miRNAs signatures in AS and characterize the mechanisms mediated by miRNAs in the pathology of this disease.

Differentially expressed mRNAs, lncRNAs, and miRNAs with associated co-expression and ceRNA networks in ankylosing spondylitis

Ankylosing spondylitis (AS) is a chronic autoimmune disease characterized by systemic inflammation and pathological osteogenesis. However, the genetic etiology of AS remains largely unknown. This study aimed to explore the potential role of coding and noncoding genes in the genetic mechanism of AS. Using microarray analyses, this study comprehensively compared lncRNA, microRNA, and mRNA profiles in hip joint ligament tissues from patients with AS and controls. A total of 661 lncRNAs, 574 mRNAs, and 22 microRNAs were differentially expressed in patients with AS compared with controls. Twenty-two of these genes were then validated using real-time polymerase chain reaction. Gene ontology and pathway analyses were performed to explore the principal functions of differentially expressed genes. The pathways were involved mainly in immune regulation, intercellular signaling, osteogenic differentiation, protein synthesis, and degradation. Gene signal transduction network, coding-noncoding co-expression network, and competing endogenous RNA expression network were constructed using bioinformatics methods. Then, two miRNAs, miR-17-5p and miR-27b-3p, that could increase the osteogenic differentiation potentials of ligament fibroblasts were identified. Finally, differentially expressed, five lncRNAs, four miRNAs, and five mRNAs were validated using quantitative real-time polymerase chain reaction. These results suggested that mRNAs, lncRNAs, and microRNAs were involved in AS pathogenesis. The findings might help characterize the pathogenesis of AS and provide novel therapeutic targets for patients with AS in the future.

MicroRNA-146a knockdown suppresses the progression of ankylosing spondylitis by targeting dickkopf 1

Ankylosing spondylitis (AS) seriously threatens healthy and life quality of patients, however, there is no extremely effective drug to cure the disease. Therefore, it is urgent to understand molecular basis in the progression of AS. MicroRNA-146a (miR-146a) has been demonstrated to be associated with the development of AS. However, its molecular mechanism has not been fully established. In this study, it is found that the expression levels of miR-146a and dickkopf 1 (DKK1) were respectively upregulated and downregulated in hip capsule tissues of AS patients. Moreover, a negative correlation was displayed between miR-146a and DKK1 expression. Functional analysis revealed that miR-146a inhibitor restrained cell proliferation and osteogenic potential as well as enhanced apoptosis in AS fibroblasts, while miR-146a overexpression enhanced proliferation and osteogenic potential of AS fibroblasts. Bioinformatics analysis, dual luciferase reporter assays, qRT-PCR and immunoblotting assays revealed that miR-146a inhibited DKK1 expression by directly targeting 3'UTR region of DKK1. Mechanism studies further revealed that loss of DKK1 partly reversed the effect of miR-146a inhibitor on cell proliferation, apoptosis and osteogenic potential in AS fibroblasts. Taken together, our finding revealed that miR-146a knockdown hindered AS progression partially by regulating target DKK1 expression, offering a potential therapy application for AS patients.

microRNA cluster 106a~363 is involved in T helper 17 cell differentiation

T-helper cell type 17 (Th17) mediated inflammation is associated with various diseases including autoimmune encephalitis, inflammatory bowel disease and lung diseases such as chronic obstructive pulmonary disease and asthma. Differentiation into distinct T helper subtypes needs to be tightly regulated to ensure an immunological balance. As microRNAs (miRNAs) are critical regulators of signalling pathways, we aimed to identify specific miRNAs implicated in controlling Th17 differentiation. We were able to create a regulatory network model of murine T helper cell differentiation by combining Affymetrix mRNA and miRNA arrays and in silico analysis. In this model, the miR-212~132 and miR-182~183 clusters were significantly up-regulated upon Th17 differentiation, whereas the entire miR-106~363 cluster was down-regulated and predicted to target well-known Th17 cell differentiation pathways. In vitro transfection of miR-18b, miR-106a and miR-363-3p into primary murine Cd4⁺ lymphocytes decreased expression of retinoid-related orphan receptor c (Rorc), Rora, Il17a and Il17f, and abolished secretion of Th17-mediated interleukin-17a (Il17a). Moreover, we demonstrated target site-specific regulation of the Th17 transcription factors Rora and nuclear factor of activated T cells (Nfat) 5 by miR-18b, miR-106a and miR-363-3p through luciferase reporter assays. Here, we provide evidence that miRNAs are involved in controlling the differentiation and function of T helper cells, offering useful tools to study and modify Th17-mediated inflammation.

Interleukin-34 inhibits hepatitis B virus replication in vitro and in vivo

Background

The hepatitis B virus (HBV) infection could activate the immune system and induce extensive inflammatory response. As the most important inflammatory factor, interleukins are critical for anti-viral immunity. Here we investigated whether interleukin-34 (IL-34) play a role in HBV infection.

Methodology/Principal findings

In this study, we first found that both serum IL-34 and IL-34 mRNA in PBMCs in chronic HBV patients was significantly decreased compared to the healthy controls. Furthermore, both IL-34 protein and mRNA levels were declined hepatoma cells expressing HBV. In addition, the clinical parameters analysis found that serum IL-34 was significantly associated with HBV DNA (P = 0.0066), ALT (P = 0.0327), AST (P = 0.0435), TB (P = 0.0406), DB (P = 0.0368) and AFP (P = 0.0225). Correlation analysis also found that serum IL-34 negatively correlated with HBV DNA copies, ALT and AST. In vitro studies found that IL-34 treatment in HepAD38 and HepG2.2.15 cells markedly inhibited HBV DNA, total RNA, 3.5kb mRNA and HBc protein. In vivo studies further demonstrated IL-34 treatment in HBV transgenic mice exhibited greater inhibition on HBV DNA, total RNA, 3.5kb mRNA and HBc protein, suggesting the effect to IL-34 on HBV is likely due to host innate or adaptive immune response.

Conclusions/Significance

Our study identified a novel interleukin, IL-34, which has anti-viral activity in HBV replication in hepatocytes in vitro and in vivo. These data suggest a rationale for the use of IL-34 in the HBV treatment.

Novel Immune Mechanisms in Hypertension and Cardiovascular Risk

PURPOSE OF REVIEW

Hypertension is a common disorder with substantial impact on public health due to highly elevated cardiovascular risk. The mechanisms still remain unclear and treatments are not sufficient to reduce risk in majority of patients. Inflammatory mechanisms may provide an important mechanism linking hypertension and cardiovascular risk. We aim to review newly identified immune and inflammatory mechanisms of hypertension with focus on their potential therapeutic impact.

RECENT FINDINGS

In addition to the established role of the vasculature, kidneys and central nervous system in pathogenesis of hypertension, low-grade inflammation contributes to this disorder as indicated by experimental models and GWAS studies pointing to SH2B3 immune gene as top key driver of hypertension. Immune responses in hypertension are greatly driven by neoantigens generated by oxidative stress and modulated by chemokines such as RANTES, IP-10 and microRNAs including miR-21 and miR-155 with other molecules under investigation. Cells of both innate and adoptive immune system infiltrate vasculature and kidneys, affecting their function by releasing pro-inflammatory mediators and reactive oxygen species.

SUMMARY

Immune and inflammatory mechanisms of hypertension provide a link between high blood pressure and increased cardiovascular risk, and reduction of blood pressure without attention to these underlying mechanisms is not sufficient to reduce risk.