Artikel
NF-κB plays an important role in mesenchymal stem cell invasion in vitro
NF-κB spielt eine wichtige Rolle bei der Invasion von humanen mesenchymalen Stammzellen in vitro
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Veröffentlicht: | 28. September 2006 |
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Gliederung
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Background: Several publication have shown, that TNF-α plays an important role in bone healing. The exact molecular mechanisms of stem cell migration and invasion during fracture healing are unknown. Therefore, we have investigated the influence of TNF-α on migration and invasion of human mesenchymal stem cells (hMSCs) and the relevance of the NF-κB signal transduction pathway.
Methods: The dominant-negative mutant of IκB kinase 2 (dn-IKK-2) was over-expressed in hMSCs using lentiviral gene transfer. Green fluorescent protein (eGFP) was used as a negative control. Over-expression of dn-IKK-2 was conformed by RT-PCR and western blot. Inhibition of nuclear translocation of NF-κB (p65) was investigated by immunocytochemistry. Human extracellular matrix was used in invasion and migration assays. Cells were stimulated with 50 ng/ml human recombinant TNF-α
Results: 60% ± 10% of hMSCs were successfully transduced using a lentiviral titer of 1 x 10*4 TU/ml. After blastizidine selection 98% of hMSCs expressed the transgene. TNF-α caused a nuclear translocation of NF-κB (p65) within 30 minutes. Translocation was almost completely blocked by over-expression of dn-IKK-2. Furthermore, TNF-α stimulated the migration and invasion of hMSCs through human extracellular matrix. Overexpression of dn-IKK-2 caused a significant decrease of stem cell migration and invasion.
Conclusion: This study shows for the first time that NF-κB is found in human mesenchymal stem cells and is regulated via IKK-2 after stimulation with TNF-α. Furthermore, we have shown that the NF-κB signal transduction pathway plays a critical role in TNF-α-induced migration of hMSCs. Our results support the hypothesis, that NF-κB signal transduction pathway may plays a critical role in TNF-α-mediated migration of hMSCs during fracture healing.