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Researchers from Ritsumeikan University publish new studies and findings in the area of DNA research
2009 OCT 26 - (NewsRx.com) -- "Serum MBP, also known as MBL, is a C-type lectin that is known to be a soluble host defense factor involved in innate immunity. It has been well established that dying microbes and apoptotic cells release highly viscous DNA that induces inflammation and septic shock, and apoptotic cells display fragmented DNA on their surfaces," scientists in Japan report. "However, PRRs that mediate the recognition and clearance of free DNA and fragmented DNA in apoptotic cells have not been characterized clearly. Although MBP was reported recently to bind DNA as a novel ligand, binding characterization and the recognition implications have not been addressed yet. In this study, we show that MBP can bind DNA and RNA in a calcium-dependent manner from a variety of origins, including bacteria, plasmids, synthetic oligonucleotides, and fragmented DNA of apoptotic cells. Direct binding and competition studies indicate that MBP binds nucleic acids via its CRD to varying degrees and that MBP binds dsDNA more effectively than ssDNA and ssRNA. Furthermore, we reveal that the MBP-DNA complex does not trigger complement activation via the MBP lectin pathway, and the lectin pathway of complement activation is required for MBP-mediated enhancement of phagocytosis of targets bearing MBP ligands and that MBP can recognize the fragmented DNA presented on apoptotic cells," wrote N. Nakamura and colleagues, Ritsumeikan University. The researchers concluded: "Therefore, we propose that the MBP lectin pathway may support effective recognition and clearance of cellular debris by facilitating phagocytosis, possibly through immunomodulatory mechanisms, thus preventing autoimmunity. J. Leukoc. Biol. 86: 737-748; 2009." Nakamura and colleagues published their study in the Journal of Leukocyte Biology (Characterization of the interaction between serum mannan-binding protein and nucleic acid ligands. Journal of Leukocyte Biology, 2009;86(3):737-748). For additional information, contact B.Y. Ma, Ritsumeikan University, Research Center Glycobiotechnol, 1-1-1 Noji Higashi, Shiga 5258577, Japan. The publisher's contact information for the Journal of Leukocyte Biology is: Federation American Society Experimental Biology, 9650 Rockville Pike, Bethesda, MD 20814-3998, USA. Keywords: Japan, DNA Research, DNA, Inflammation, Leukocyte Biology, Phagocytosis, Septic Shock, Ritsumeikan University. This article was prepared by Proteomics Weekly editors from staff and other reports. Copyright 2009, Proteomics Weekly via NewsRx.com.
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