miR-142-3p is essential for hematopoiesis and affects cardiac cell fate in zebrafish.
ABSTRACT MicroRNAs (miRNAs) play a pivotal role during embryonic development and are required for proper organogenesis, including hematopoiesis. Recent studies suggest that, in the early mesoderm, there is an interaction between the hematopoietic and cardiac lineages. However, whether miRNAs can affect other lineages remains unknown. Therefore, we investigated whether hematopoietic miR-142-3p modulated the mesoderm formation. We report that knockdown (KD) of miR-142-3p, a hematopoietic-specific miRNA, in zebrafish resulted in loss of hematopoiesis during embryonic development. Intriguingly, we observed abnormal cardiac phenotypes and insufficiency of somitegenesis in KD-morphants. In the early developmental stage, a tiny heart, contractile dysfunction in the ventricle, cardiac arrhythmia (e.g. a 2:1 ratio of atrial:ventricular beating), and bradycardia were consistently observed. Histological examination revealed severe hypoplasia of the ventricle and disrupted muscle alignment. To determine the mechanism, we performed DNA microarray analysis. The results revealed that the expression of several mesodermal genes essential for the formation of cardiac and somatic mesoderm, such as no tail, T-box gene 16, mesoderm posterior a, one eye pinhead, and rho-associated, coiled-coil containing protein kinase (Rock2a), were increased in miR-142-3p KD-morphants. The luciferase reporter assay revealed that miR-142-3p repressed luciferase activity on the Rock2a 3'-UTR. The findings of the present study indicate that miR-142-3p plays a critical role in hematopoiesis, cardiogenesis, and somitegenesis in the early stage of mesoderm formation via regulation of Rock2a.
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ABSTRACT: MicroRNAs are endogenous, small non-coding RNAs approximately 18-26 nucleotides in length that regulate target gene expression at the post-transcription level. Interferon-γ (IFN-γ) is a Th1 cytokine that is involved in both the innate and adaptive immune responses. We previously identified two IFN-γ genes in green-spotted puffer fish (Tetraodon nigroviridis). To determine whether miRNAs participate in IFN-γ-related immune responses, T. nigroviridis spleen cells were treated with recombinant IFN-γ isoforms, and a Solexa high-throughput sequencing method was used to identify miRNAs. In total, 1,556, 1,538 and 1,573 miRNAs were found in the three samples, and differentially expressed miRNAs were determined. In total, 398 miRNAs were differentially expressed after rIFN-γ1 treatment, and 438 miRNAs were differentially expressed after rIFN-γ2 treatment; additionally, 403 miRNAs were differentially expressed between the treatment groups. Ten differentially expressed miRNAs were chosen for validation using qRT-PCR. Target genes for the differentially expressed miRNAs were predicted, and GO and KEGG analyses were performed. This study provides basic knowledge regarding fish IFN-γ-induced miRNAs and offers clues for further studies into the mechanisms underlying fish IFN-γ-mediated immune responses.PLoS ONE 01/2014; 9(5):e96336. · 3.53 Impact Factor
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ABSTRACT: MicroRNA (miR)-142 is up-regulated in the brain in HIV and SIV encephalitis (SIVE). We identified the cell types where miR-142 is up-regulated and its relevant downstream target. Fluorescent in situ hybridization combined with immunofluorescent labeling revealed that miR-142-3p and -5p are expressed within hippocampal neurons and myeloid cells in SIVE. Sirtuin1 (SIRT1) was predicted as a potential miR-142 target by analysis of its 3'-UTR and bioinformatic analysis of factors linked to altered hippocampal gene expression profile in SIVE. Overexpression of pre-miR-142 in HEK293T cells led to a 3.7-fold decrease in SIRT1 protein level. Examination of the individual effects of miR-142-5p and miR-142-3p through overexpression and inhibition studies revealed that significant effects on SIRT1 occurred only with miR-142-5p. Luciferase reporter assays revealed a 2.3-fold inhibition of expression due to interaction of miR-142 with the SIRT1 3'-UTR, mutation analysis revealed that only the miR-142-5p target site was active. MiR-142 expression in primary human neurons led to a small (1.3-fold) but significant decrease in SIRT1 protein level. Furthermore, qRT-PCR revealed up-regulation of miR-142-3p (6.4-fold) and -5p (3.9-fold) and down-regulation of SIRT1 (33-fold) in macrophages/microglia from animals with SIVE. We have therefore elucidated a miR-mediated mechanism of regulation of SIRT1 expression in SIVE.-Chaudhuri, A. D., Yelamanchili, S. V., Marcondes, M. C. G., Fox, H. S. Up-regulation of microRNA-142 in simian immunodeficiency virus encephalitis leads to repression of sirtuin1.The FASEB Journal 06/2013; · 5.70 Impact Factor
- Medecine sciences: M/S 29(6-7):574-6. · 0.56 Impact Factor