IntroductionAbnormal toll-like receptor (TLR)3 signaling plays an indispensable role in pathogenesis of both experimental and human rheumatoid arthritis, and microRNAs (miRNAs) might orchestrate this signaling pathway. This study was performed to determine the relationship between miR-26a and TLR3 in rat macrophages and to observe effects of miR-26a mimic on pristane induced arthritis (PIA) in rats.MethodsDual luciferase reporter assay was used to validate the direct interaction between miR-26a (a candidate miRNA to target tlr3 mRNA) and tlr3 3′UTR. MiR-26a regulation on TLR3 gene expression was determined using RT-qPCR and Western blotting after miR-26a mimics and inhibitors were transfected into rat macrophage line NR8383 cells. Poly I:C (TLR3 ligand) was used to trigger TLR3 activation, and mRNA expression of its downstream cytokines interferon (ifn)-β and tumor necrosis factor (tnf)-α was accordingly detected to determine the regulation of TLR3 signaling. Expressions of TLR3 and miR-26a were detected during rat bone marrow derived macrophage (BMDM) induction, in pristane stimulated NR8383 cells and spleens from methotrexate (MTX) treated PIA rats. A miR-26a mimic was administrated intraperitoneally to PIA rats, and arthritis severity was evaluated by macroscopic or microscopic observations.ResultsDirect target relationship between miR-26a and tlr3 mRNA in rats was confirmed. Modifications of miR-26a function by transfection of miR-26a mimics and inhibitors exhibited corresponding repression and augmentation of TLR3 and its signaling downstream cytokine expressions in NR8383 cells. The alteration of miR-26a expression was negatively related with TLR3 expression during BMDM induction, in pristane-primed NR8383 cells and PIA rat spleens. Moreover, both abnormal expressions were rescued in MTX treated arthritis rat spleens. The miR-26a mimic treatment displayed the depression of TLR3 expression and ameliorated the disease severity in the rats with pristane induced arthritis.ConclusionsMiR-26a negatively regulates TLR3 signaling via targeting of TLR3 itself in rat macrophages, and this finding provides a novel insight into abnormal TLR3 overexpression during experimental arthritis.
Angiotensin II (Ang II) plays a pivotal role in cardiac fibrosis, and microRNAs (miRNAs) have been shown to participate in diverse pathological processes. Our aim is to identify the Ang II-induced miRNAs in cardiac fibroblasts (CFs). The miRNA array was used to analyze the miRNA expression profile in CFs treated by Ang II and control cells. Stem-loop real-time PCR was performed to re-measure the levels of the differentially expressed miRNAs. Analysis of miRNA arrays showed that 33 miRNAs were differentially expressed (13 up- and 20 downregulated) in response to Ang II (100 nM) for 24 h as compared to control cells. Quantitative PCR revealed that Ang II upregulated the levels of miR-132, -125b-3p and miR-146b but downregulated the levels of miR-300-5p, -204* and miR-181b in CFs. The trend of miRNA change is consistent with microarray and qRT-PCR. Bioinformatic analysis revealed that MMP9 as the target of miR-132, MMP16 as the target of miR-146b and TIMP3 as the target of miR-181b have been listed in the miR database with experimentally validated targets, indicating the potential role of those miRNAs in cardiac fibrosis. Our results demonstrated that we did identify a subset of miRNAs that was differentially expressed in Ang II-treated CFs, which provide a starting point to explore their potential roles in cardiac fibrosis and hypertension.
This study aimed to observe the effects of Se deficiency on epiphyseal plates of two generation DA rats fed with artificial total synthetic low Se diet. All F0 and F1 DA rats were fed with synthetic low Se diet (SeD group) and low Se diet supplied with Se (SeS group). The levels of selenium and enzyme activities of GPx were detected in plasma of the rats. General growth of bone and articular cartilage was measured macroscopically and microscopically. The epiphyseal plate of femur heads or tibia were obtained to histological and immunohistochemical examinations. The cartilage from left knee joints and femur heads was used to detect the gene expression of collagens, ADAMTSs and several selenoproteins by RT-qPCR. Two generation SeD rats showed Se insufficiency status. The thicknesses of the femur and tibial epiphyseal plates in both F0 and F1 SeD rats were significantly less than that of SeS rats. In F1 generation, SeD rats showed much fewer proliferative chondrocyte layers than SeS ones. Importantly, two generation SeD rats both showed significantly more serious pathological changes of epiphyseal plates. In two generation rats, gene expressions of COL II, GPx1 and GPx4 were significantly down-regulated in SeD rats than SeS ones; meanwhile ADAMTS-4 showed an up-regulated expression in cartilage. Dietary Se deficiency can apparently cause epiphyseal plate lesion and decrease cartilage type II collagen production and GPx1 activity in two generation DA rats fed with the artificial total synthesis low Se diet.
Selenium is an essential micronutrient and exerts its biological functions predominantly through selenoproteins. Selenium deficiency is associated with cartilage function. This study demonstrated that all 24 selenoprotein transcripts in mouse genome were detectable in ATDC5 chondrocytes except deiodinase 1 (DIO1), DIO2, and selenoprotein V (Sel V), while all 25 selenoprotein transcripts in human genome were detectable in C28/I2 chondrocytes except glutathione peroxidase 6 (GPx6) and DIO1. In addition, gene expression of five selenoproteins (GPx1, Sel H, Sel N, Sel P, and Sel W) was up-regulated and two selenoproteins (SPS2 and Sel O) was down-regulated by sodium selenite (Se) in both ATDC5 and C28/I2 cells. Gene expression of six selenoproteins (TrxR1, Sel I, Sel M, Sel R, Sel S, Sel T) and one selenoprotein (GPx3) was up-regulated by Se in ATDC5 and C28/I2 cells, respectively. Gene expression of one selenoprotein (TrxR2) was down-regulated by Se only in ATDC5 cells. Further transcription inhibition assay showed that both transcriptional and posttranscriptional mechanisms involved in Se-regulated gene expression of GPx1, TrxR1, TrxR2, SPS2, Sel O, and Sel S. However, Se-regulated gene expression of Sel H, Sel I, Sel M, Sel N, Sel P, Sel R, Sel T, and Sel W mainly at posttranscriptional level. Moreover, new protein synthesis inhibition assay indicated that Se-mediated new protein synthesis also played roles in Se-regulated gene expression of GPx1, TrxR1, TrxR2, Sel H, Sel O, Sel P, Sel R, and Sel W. In summary, this study described the selenoprotein transcriptome, Se-regulated selenoproteins and possible mechanisms involved in chondrocytes.
Long noncoding RNAs (lncRNAs) are defined as noncoding RNAs that are longer than ~200 nucleotides and lack protein-encoding capacity. It has been shown that lncRNAs are involved in multiple human diseases by regulating gene expression at various levels. However, studies of lncRNAs in the cardiovascular system are still in their infancy. A growing body of evidence suggests that lncRNAs are also involved in common cardiovascular diseases, including cardiac development, atherosclerosis, myocardial infarction, heart failure, hypertension and aneurysms. In this review, we summarize the current understanding of lncRNAs in common cardiovascular diseases in an effort to better elucidate the molecular mechanism of cardiovascular diseases and provide a basis for exploring new therapeutic targets in those diseases.
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