The role of IFN-alpha and nitric oxide in the release of HMGB1 by RAW 264.7 cells stimulated with polyinosinic-polycytidylic acid or lipopolysaccharide.
High mobility group protein 1 (HMGB1) is a nonhistone nuclear protein with a dual function. Inside the cell, HMGB1 binds to DNA and modulates a variety of processes, including transcription. Outside the cell, HMGB1 displays cytokine activity and can promote inflammation, serving as a mediator in models of shock and arthritis. In in vitro studies, proinflammatory molecules such as LPS, lipoteichoic acid, dsRNA, TNF-alpha, and IFN-gamma can induce HMGB1 release from macrophages. To define further the release process, we investigated the role of the downstream mediators, NO and IFN-alpha, in the release of HMGB1 from RAW 264.7 macrophage cells stimulated with LPS or polyinosinic-polycytidylic acid (poly(I:C)). In these experiments, 1400W, an inhibitor of NO production by the inducible NO synthase, reduced HMGB1 release stimulated by LPS, but not poly(I:C), whereas neutralizing IFN-alpha prevented HMGB1 release induced by poly(I:C), but not LPS. The addition of an NO donor and rIFN-alpha to RAW 264.7 cells caused HMGB1 release. Furthermore, inhibition of JNK activation attenuated HMGB1 release induced by either LPS or poly(I:C). Analysis of bone marrow-derived macrophages stimulated by LPS or poly(I:C) showed patterns of HMGB1 release similar to those of RAW 264.7 cells. Together, these experiments indicate that, although both LPS and poly(I:C) induce HMGB1 release from RAW 264.7 cells and murine macrophages, the response is differentially dependent on NO and IFN-alpha.
Jiang
Weiwen
W
Division of Rheumatology and Immunology, Department of Medicine, Duke University, Durham, NC 27710, USA.
Pisetsky
David S
DS
D000818:Animals; D002460:Cell Line; D024243:HMGB1 Protein / Q000378:metabolism*; D016898:Interferon-alpha / Q000378:metabolism*; D048031:JNK Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D009569:Nitric Oxide / Q000378:metabolism*; D011070:Poly I-C / Q000494:pharmacology*; D034622:RNA Interference
D024243:HMGB1 Protein; D016898:Interferon-alpha; D008070:Lipopolysaccharides; D009569:Nitric Oxide; D048031:JNK Mitogen-Activated Protein Kinases; D011070:Poly I-C