194 Recombinant High-mobility Group Box 1 Protein (HMGB-1) Promotes Myeloid Differentiation Primary Response Protein 88 (Myd88) Upregulation in Mouse Primary Cortical Neurons

Abstract

INTRODUCTION: Myeloid differentiation primary response protein 88 (Myd88) is a vital factor for inflammation and immunity, and high-mobility group box 1 protein (HMGB-1) is released after injury from neurons and may contribute to the initial stages of inflammatory response. Therefore, the current study was intended to investigate the expression of Myd88 in the cultured neurons following recombinant HMGB-1 addition and to clarify the potential role of Myd88 after neuron injury in vitro. METHODS: The cultured neurons were randomly divided into six groups: control group and HMGB-1 groups at hours 1, 6, 12, 24, and 48. The cultured neurons in HMGB-1 groups were subjected to addition of recombinant HMGB-1. The expression of Myd88 was assessed by quantitative real-time polymerase chain reaction (PCR), Western blotting and immunofluorescence, and nuclear factor kappa B (NF-kB) binding activity was detected by electrophoretic mobility shift assay (EMSA), and the levels of tumor necrosis factor-a (TNF-a) and Interleukin 1ß (IL-1ß) were measured by quantitative real-time PCR. RESULTS: The elevated mRNA and protein levels of Myd88, peaking at 24 h, were detected after HMGB-1 addition. NF-kB, TNF-a, and IL-1ß also ascended significantly after HMGB-1 addition. Interestingly, Myd88 increasingly expressed in a parallel time course to the upregulation of NF-kB, TNF-a, and IL-1ß. CONCLUSION: These findings indicated the possible role of Myd88 in the inflammatory response after neuron injury, and might provide an attractive therapeutic approach of targeting the Myd88 cascade to achieve better outcomes for patients after central nervous system injury.