Mechanical stress induces tumor necrosis factor-{alpha} production through Ca2+ release-dependent TLR2 signaling.
We studied centrifugation-mediated mechanical stress-induced tumor necrosis factor-alpha (TNF-alpha) production in the monocyte-like cell line THP-1. The induction of TNF-alpha by mechanical stress was dependent on the centrifugation speed and produced the highest level of TNF-alpha after 1 h of stimulation. TNF-alpha production returned to normal levels after 24 h of stimulation. Mechanical stress also induced Toll-like receptor-2 (TLR2) mRNA in proportion to the expression of TNF-alpha. The inhibition of TLR2 signaling by dominant negative myeloid differentiation factor 88 (MyD88) blocked TNF-alpha expression response to mechanical stress. After transient overexpression of TLR2 in HEK-293 cells, mechanical stress induced TNF-alpha mRNA production. Interestingly, mechanical stress activated the c-Src-dependent TLR2 phosphorylation, which is necessary to induce Ca(2+) fluxes. When THP-1 cells were pretreated with BAPTA-AM, thapsigargin, and NiCl(2).6H(2)O, followed by mechanical stimulation, both TLR2 and TNF-alpha production were inhibited, indicating that centrifugation-mediated mechanical stress induces both TLR2 and TNF-alpha production through Ca(2+) releases from intracellular Ca(2+) stores following TLR2 phosphorylation. In addition, TNF-alpha treatment in THP-1 cells induced TLR2 production in response to mechanical stress, whereas the preincubation of anti-TNF-alpha antibody scarcely induced the mechanical stress-mediated production of TLR2, indicating that TNF-alpha produced by mechanically stimulated THP-1 cells affected TLR2 production. We concluded that TNF-alpha production induced by centrifugation-mediated mechanical stress is dependent on MyD88-dependent TLR2 signaling that is associated with Ca(2+) release and that TNF-alpha production induced by mechanical stress affects TLR2 production.
Graduate School of Biotechnology and Institute of Life Science and Resources, Kyung Hee Univ., Yongin 449-701, Korea.
Han Geun
HG
Kim
Joo Yun
JY
Kim
Min Geun
MG
Gim
Jung Min
JM
Lee
Dae Kyun
DK
Chung
D000906:Antibodies / Q000494:pharmacology; D002118:Calcium / Q000037:antagonists & inhibitors; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology*; D002460:Cell Line; D045744:Cell Line, Tumor; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D004731:Endotoxins / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D009000:Monocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D053594:Myeloid Differentiation Factor 88 / Q000235:genetics; D016328:NF-kappa B / Q000378:metabolism; D009532:Nickel / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D011112:Polymyxin B / Q000494:pharmacology; D011720:Pyrazoles / Q000494:pharmacology; D011743:Pyrimidines / Q000494:pharmacology; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases / Q000037:antagonists & inhibitors; D013314:Stress, Mechanical; D019284:Thapsigargin / Q000494:pharmacology; D051195:Toll-Like Receptor 2 / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology
C108123:4-amino-5-(4-methylphenyl)-7-(tert-butyl)pyrazolo(3,4-d)pyrimidine; D000906:Antibodies; D004731:Endotoxins; D004791:Enzyme Inhibitors; C507779:MYD88 protein, human; D053594:Myeloid Differentiation Factor 88; D016328:NF-kappa B; D011720:Pyrazoles; D011743:Pyrimidines; C495342:TLR2 protein, human; D051195:Toll-Like Receptor 2; D014409:Tumor Necrosis Factor-alpha; C070379:1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester; D004533:Egtazic Acid; D019284:Thapsigargin; C022838:nickel chloride; D009532:Nickel; D015544:Inositol 1,4,5-Trisphosphate; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D011112:Polymyxin B; D002118:Calcium