1. Role of IRAK1 on TNF-induced Proliferation and NF-?B Activation in Human Bone Marrow Mesenchymal Stem Cells
- Author
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Ji won Yang, You-Sun Kim, Chang Pyo Hong, Hyun Hwa Cho, Jin Sup Jung, Jong Myung Kim, Sun-Young Lee, and Kuen Tak Suh
- Subjects
Male ,MAPK/ERK pathway ,MAP Kinase Signaling System ,Physiology ,Bone Marrow Cells ,Downregulation and upregulation ,Humans ,Protein Kinase Inhibitors ,Cells, Cultured ,Cell Proliferation ,Tumor Necrosis Factor-alpha ,Chemistry ,Cell growth ,Kinase ,NF-kappa B ,Mesenchymal Stem Cells ,IRAK1 ,Middle Aged ,TRADD ,TNF Receptor-Associated Death Domain Protein ,Interleukin-1 Receptor-Associated Kinases ,Oligodeoxyribonucleotides ,Cyclooxygenase 2 ,Receptors, Tumor Necrosis Factor, Type I ,Gene Knockdown Techniques ,Cancer research ,Phosphorylation ,Female ,RNA Interference ,Tumor necrosis factor alpha ,Mitogen-Activated Protein Kinases - Abstract
In this study, we determined the effect of TNF-α on hBMSCs proliferation as well as the role of IL-1 receptor-associated kinase 1 (IRAK1) on TNF-α signaling. Western blot analysis revealed that TNF-α treatment increased the phosphorylation of IRAK1 in hBMSCs. The downregulation of IRAK1 inhibited TNF-α-induced NF-ĸB activation and COX-2 expression. TNF-α treatment increased hBMSCs proliferation in a dose-dependent manner and increased ERK, JNK, and NF-ĸB activity. U0126, an ERK inhibitor, decreased hBMSCs proliferation and significantly blocked TNF-α -induced hBMSCs proliferation. In cells with IRAK1 or TRADD downregulation, the U0126 treatment inhibited hBMSCs proliferation and significantly suppressed TNF-α-induced hBMSCs proliferation. The downregulation of IRAK1 or TRADD inhibited TNF-α-induced ERK and JNK activation, and hBMSCs proliferation. Inhibition of NF-ĸB by decoy oligonucleotides reduced the TNF-α-induced hBMSCs proliferation. Immunoprecipitation analysis showed that IRAK1 does not physically interact with TNF receptor 1 (TNFR1) even in the presence of TNF-α. Suppression of IRAK1 binding protein (IRAK1BP1) inhibited TNF-α-induced increase of the proliferation and ERK1 phosphorylation of hBMSCs in the presence of TNF-α. Our data indicate that TNF-α modulates hBMSCs proliferation through ERK signaling pathways, and that IRAK1 plays an important role in TNF-α-induced NF-ĸB activation in hBMSCs.
- Published
- 2012