Tea Flavonoids Induced Differentiation of Peripheral Blood-derived Mononuclear Cells into Peripheral Blood-derived Endothelial Progenitor Cells and Suppressed Intracellular Reactive Oxygen Species Level of Peripheral Blood-derived Endothelial Progenitor C

Endothelial dysfunction in atherosclerosis is associated with increasing oxidative stress that could be reversed by antioxidant. Therefore epigallocatechin gallate (EGCG), epicatechin gallate (ECG), epigallocatechin (EGC) and catechin (C) of tea flavonoids were investigated for their roles in regenerating endothelial cell. Peripheral blood mononuclear cells (PB-MNCs) were isolated, plated and cultured in medium with/without treatment of EGCG, ECG, EGC and C. Results showed that among all EGCG, ECG, EGC and C concentrations tested, 12.5 µmol/L was not cytotoxic for peripheral blood-derived endothelial progenitor cells (PB-EPCs). Treatment of EGCG, ECG, EGC or C increased the percentages of CD34, CD133, VEGFR-2 expressions and suppressed hydrogen peroxide-induced percentages of reactive oxygen species (ROS) level in PB-EPCs. Taken together, our current results showed that EGCG, ECG, EGC or C of tea flavonoids could induce differentiation of PB-MNCs into PB-EPCs as well as protect PB-EPCs from oxidative damage by suppresing the intracellular ROS levels.

An Anti-apoptotic Role of NF-κB in TNFα-induced Apoptosis in an Ameloblastoma Cell Line / Oral Science International

Nuclear factor-κB (NF-κB) is involved in the promotion of cell survival in a variety of cell types. The present study focused on the role of NF-κB in TNFα-induced apoptosis in an ameloblastoma. Immunohistochemical staining revealed p65 NF-κB protein to be expressed in ameloblastoma tissues. Furthermore, immunoblotting and immunocytochemistry analyses showed that the stimulation of TNFα in an ameloblastoma cell line (AM-1) induced p65 NF-κB translocation from the cytoplasm to the nucleus, indicating NF-κB activation. These findings were confirmed by an NF-κB luciferase reporter assay, which detected enhanced NF-κB transcription activity of AM-1 cells by TNFα stimulation. Moreover, pretreatment with SN50, a nuclear translocation inhibitor, prior to TNFα stimulation, effectively inhibited TNFα-induced NF-κB activation in AM-1 cells. In order to reveal the role of NF-κB activation during TNFα-induced apoptosis in AM-1 cells, an apoptosis assay was performed, and showed that the potential of TNFα in inducing apoptosis in AM-1 cells was significantly elevated by inhibiting the NF-κB activation. These results suggest that NF-κB plays an anti-apoptotic role in TNFα-induced apoptosis in AM-1 cells.