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Hiroshima-shi, Japan

Nakanishi K.,Programs for Applied Biomedicine | Nakasa T.,Programs for Applied Biomedicine | Tanaka N.,Programs for Applied Biomedicine | Ishikawa M.,Programs for Applied Biomedicine | And 9 more authors.
Spinal Cord | Year: 2010

Study design: We investigated microRNA (miRNA) expression after spinal cord injury (SCI) in mice. Objectives: The recent discovery of miRNAs suggests a novel regulatory control over gene expression during plant and animal development. MiRNAs are short noncoding RNAs that suppress the translation of target genes by binding to their mRNAs, and play a central role in gene regulation in health and disease. The purpose of this study was to examine miRNA expression after SCI. Setting: Department of Orthopaedic Surgery, Graduate School of Biomedical Sciences, Hiroshima University. Methods: We examined the expression of miRNA (miR)-223 and miR-124a in a mouse model at 6 h, 12 h, 1 day, 3 days and 7 days after SCI using quantitative PCR. The miRNA expression was confirmed by in situ hybridization. Results: Quantitative PCR revealed two peaks of miR-223 expression at 6 and 12 h and 3 days after SCI. MiR-124a expression decreased significantly from 1 day to 7 days after SCI. In situ hybridization demonstrated the presence of miR-223 around the injured site. However, miR-124a, which was present in the normal spinal cord, was not observed at the injured site. Conclusion: Our results indicate a time-dependent expression pattern of miR-223 and miR-124a in a mouse model of SCI. In this study, the time course of miRNA-223 expression may be related to inflammatory responses after SCI, and the time course of decreased miR-124a expression may reflect cell death. © 2010 International Spinal Cord Society All rights reserved. Source

Nakasa T.,Programs for Applied Biomedicine | Ishikawa M.,Programs for Applied Biomedicine | Shi M.,Programs for Applied Biomedicine | Shibuya H.,Programs for Applied Biomedicine | And 2 more authors.
Journal of Cellular and Molecular Medicine | Year: 2010

MicroRNA (miRNA)s are a class of non-coding RNAs that regulate gene expression post-transcriptionally. Muscle-specific miRNA, miRNA (miR)-1, miR-133 and miR-206 play a crucial role in the regulation of muscle development and homeostasis. Muscle injuries are a common muscloskeletal disorder, and the most effective treatment has not been established yet. The purpose of this study was to demonstrate that a local injection of double-stranded (ds) miR-1, miR-133 and 206 can accelerate muscle regeneration in a rat skeletal muscle injury model. After the laceration of the rat tibialis anterior muscle, ds miR-1, 133 and 206 mixture mediated atelocollagen was injected into the injured site. The control group was injected with control siRNA. At 1 week after injury, an injection of miRNAs could enhance muscle regeneration morphologically and physiologically, and prevent fibrosis effectively compared to the control siRNA. Administration of exogenous miR-1, 133 and 206 can induce expression of myogenic markers, MyoD1, myogenin and Pax7 in mRNA and expression in the protein level at 3 and 7 days after injury. The combination of miR-1, 133 and 206 can promote myotube differentiation, and the expression of MyoD1, myogenin and Pax7 were up-regulated in C2C12 cells in vitro. Local injection of miR-1, 133 and 206 could be a novel therapeutic strategy in the treatment of skeletal muscle injury. © 2009 The Authors Journal compilation © 2010 Foundation for Cellular and Molecular Medicine/Blackwell Publishing Ltd. Source

Niimoto T.,Programs for Applied Biomedicine | Nakasa T.,Programs for Applied Biomedicine | Ishikawa M.,Programs for Applied Biomedicine | Okuhara A.,Programs for Applied Biomedicine | And 5 more authors.
BMC Musculoskeletal Disorders | Year: 2010

Background. Interleukin (IL)-17 is an important factor in rheumatoid arthritis (RA) pathogenesis. MicroRNA (miRNA)s are a family of non coding RNAs and associated with human diseases including RA. The purpose of this study is to identify the miRNAs in the differentiation of IL-17 producing cells, and analyze their expression pattern in the peripheral blood mononuclear cells (PBMC) and synovium from RA patients. Methods. IL-17 producing cells were expanded from CD4+T cell. MiRNA microarray was performed to identify the miRNAs in the differentiation of IL-17 producing cells. Quantitative polymerase chain reaction was performed to examine the expression patterns of the identified miRNAs in the PBMC and synovium from RA and osteoarthritis (OA) patients. Double staining combining in situ hybridization and immunohistochemistry of IL-17 was performed to analyze the expression pattern of identified miRNA in the synovium. Results. Six miRNAs, let-7a, miR-26, miR-146a/b, miR-150, and miR-155 were significantly up regulated in the IL-17 producing T cells. The expression of miR-146a and IL-17 was higher than in PBMC in the patients with low score of Larsen grade and short disease duration. MiR-146a intensely expressed in RA synovium in comparison to OA. MiR-146a expressed intensely in the synovium with hyperplasia and high expression of IL-17 from the patients with high disease activity. Double staining revealed that miR-146a expressed in IL-17 expressing cells. Conclusion. These results indicated that miR-146a was associated with IL-17 expression in the PBMC and synovium in RA patients. There is the possibility that miR-146a participates in the IL-17 expression. © 2010 Niimoto et al; licensee BioMed Central Ltd. Source

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