283 research outputs found

    Differentiation and fiber type-specific activity of a muscle creatine kinase intronic enhancer

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    Background: Hundreds of genes, including muscle creatine kinase (MCK), are differentially expressed in fast- and slow-twitch muscle fibers, but the fiber type-specific regulatory mechanisms are not well understood. Results: Modulatory region 1 (MR1) is a 1-kb regulatory region within MCK intron 1 that is highly active in terminally differentiating skeletal myocytes in vitro. A MCK small intronic enhancer (MCK-SIE) containing a paired E-box/myocyte enhancer factor 2 (MEF2) regulatory motif resides within MR1. The SIE's transcriptional activity equals that of the extensively characterized 206-bp MCK 5'-enhancer, but the MCK-SIE is flanked by regions that can repress its activity via the individual and combined effects of about 15 different but highly conserved 9- to 24-bp sequences. ChIP and ChIP-Seq analyses indicate that the SIE and the MCK 5'-enhancer are occupied by MyoD, myogenin and MEF2. Many other E-boxes located within or immediately adjacent to intron 1 are not occupied by MyoD or myogenin. Transgenic analysis of a 6.5-kb MCK genomic fragment containing the 5'-enhancer and proximal promoter plus the 3.2-kb intron 1, with and without MR1, indicates that MR1 is critical for MCK expression in slow- and intermediate-twitch muscle fibers (types I and IIa, respectively), but is not required for expression in fast-twitch muscle fibers (types IIb and IId). Conclusions: In this study, we discovered that MR1 is critical for MCK expression in slow- and intermediate-twitch muscle fibers and that MR1's positive transcriptional activity depends on a paired E-box MEF2 site motif within a SIE. This is the first study to delineate the DNA controls for MCK expression in different skeletal muscle fiber types

    Central administration of C-x-C chemokine receptor type 4 antagonist alleviates the development and maintenance of peripheral neuropathic pain in mice

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    Aim To explore the roles of C-X-C chemokine receptor type 4 (CXCR4) in spinal processing of neuropathic pain at the central nervous system (CNS). Methods Peripheral neuropathic pain (PNP) induced by partial sciatic nerve ligation (pSNL) model was assessed in mice. Effects of a single intrathecal (central) administration of AMD3100 (intrathecal AMD3100), a CXCR4 antagonist, on pain behavior and pain-related spinal pathways and molecules in the L3-L5 spinal cord segment was studied compare to saline treatment. Results Rotarod test showed that intrathecal AMD3100 did not impair mice motor function. In pSNL-induced mice, intrathecal AMD3100 delayed the development of mechanical allodynia and reversed the established mechanical allodynia in a dose-dependent way. Moreover, intrathecal AMD3100 downregulated the activation of JNK1 and p38 pathways and the protein expression of p65 as assessed by western blotting. Real-time PCR test also demonstrated that substance P mRNA was decreased, while adrenomedullin and intercellular adhesion molecule mRNA was increased following AMD3100 treatment. Conclusion Our results suggest that central (spinal) CXCR4 is involved in the development and maintenance of PNP and the regulation of multiple spinal molecular events under pain condition, implicating that CXCR4 would potentially be a therapeutic target for chronic neuropathic pain.published_or_final_versio

    Inhibition Of Spinal Endothelin Type A Receptor Ameliorates Neuropathic Pain Through Down-regulation Of Mapk And Nf--ΞΊappab P65 In Rats

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    Conference Theme: Translating Evidence into PracticeLate-Breaking Poster Session 3: abstract no. EFIC5-1288 / Poster board no. 508published_or_final_versio

    Territory wide study of patients with dystrophinopathy in Hong Kong

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    Poster PresentationThis journal issues entitled: 18th International Congress of The World Muscle SocietyThis is a first territory wide study in Hong Kong on Chinese patients with dystrophinopathy on their genetic mutation, motor performance, use of steroid, and the interventions they received. This study is participated by all the paediatric departments in the eleven hospitals in Hong Kong. Clinical data was systemically collected ...postprin

    Prevalence and Characteristics of Chinese Patients With Duchenne and Becker Muscular Dystrophy-A Territory Wide Collaborative Study in Hong Kong

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    The aim of this collaborative study on Duchenne muscular dystrophy and Becker muscular dystrophy is to determine the prevalence and to develop data on such patients as a prelude to the development of registry in Hong Kong. Information on clinical and molecular findings, and patient care, was systematically collected in 2011 and 2012 from all Pediatric Neurology Units in Hong Kong. Ninety patients with dystrophinopathy were identified, and 83% has Duchenne muscular dystrophy. The overall prevalence of dystrophinopathy in Hong Kong in 2010 is 1.03 per 10 000 males aged 0 to 24 years. Among the Duchenne group, we observed a higher percentage (40.6%) of point mutations with a lower percentage (45.3%) of exon deletions in our patients when compared with overseas studies. Although we observed similar percentage of Duchenne group received scoliosis surgery, ventilation support, and cardiac treatment when compared with other countries, the percentage (25%) of steroid use is lower.link_to_OA_fulltex

    High-Affinity Inhibitors of Human NAD+-Dependent 15-Hydroxyprostaglandin Dehydrogenase: Mechanisms of Inhibition and Structure-Activity Relationships

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    BACKGROUND: 15-Hydroxyprostaglandin dehydrogenase (15-PGDH, EC 1.1.1.141) is the key enzyme for the inactivation of prostaglandins, regulating processes such as inflammation or proliferation. The anabolic pathways of prostaglandins, especially with respect to regulation of the cyclooxygenase (COX) enzymes have been studied in detail; however, little is known about downstream events including functional interaction of prostaglandin-processing and -metabolizing enzymes. High-affinity probes for 15-PGDH will, therefore, represent important tools for further studies. PRINCIPAL FINDINGS: To identify novel high-affinity inhibitors of 15-PGDH we performed a quantitative high-throughput screen (qHTS) by testing >160 thousand compounds in a concentration-response format and identified compounds that act as noncompetitive inhibitors as well as a competitive inhibitor, with nanomolar affinity. Both types of inhibitors caused strong thermal stabilization of the enzyme, with cofactor dependencies correlating with their mechanism of action. We solved the structure of human 15-PGDH and explored the binding modes of the inhibitors to the enzyme in silico. We found binding modes that are consistent with the observed mechanisms of action. CONCLUSIONS: Low cross-reactivity in screens of over 320 targets, including three other human dehydrogenases/reductases, suggest selectivity of the present inhibitors for 15-PGDH. The high potencies and different mechanisms of action of these chemotypes make them a useful set of complementary chemical probes for functional studies of prostaglandin-signaling pathways. ENHANCED VERSION: This article can also be viewed as an enhanced version in which the text of the article is integrated with interactive 3D representations and animated transitions. Please note that a web plugin is required to access this enhanced functionality. Instructions for the installation and use of the web plugin are available in Text S2
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