Expression Pattern of the Thioredoxin System in Human Endothelial Progenitor Cells and Endothelial Cells Under Hypoxic Injury

Abstract

Background and ObjectivesThe thioredoxin (TRx) system is a ubiquitous thiol oxidoreductase pathway that regulates cellular reduction/oxidation status. Although endothelial cell (EC) hypoxic damage is one of the important pathophysiologic mechanisms of ischemic heart disease, its relationship to the temporal expression pattern of the TRx system has not yet been elucidated well. The work presented here was performed to define the expression pattern of the TRx system and its correlation with cellular apoptosis in EC lines in hypoxic stress. These results should provide basic clues for applying aspects of the TRx system as a therapeutic molecule in cardiovascular diseases.Subjects and MethodsHypoxia was induced with 1% O2, generated in a BBL GasPak Pouch (Becton Dickinson, Franklin Lakes, NJ, USA) in human endothelial progenitor cells (hEPC) and human umbilical vein endothelial cells (HUVEC). Apoptosis of these cells was confirmed by Annexin-V: Phycoerythrin flow cytometry. Expression patterns of TRx; TRx reductase; TRx interacting protein; and survival signals, such as Bcl-2 and Bax, in ECs under hypoxia were checked.ResultsApoptosis was evident after hypoxia in the two cell types. Higher TRx expression was observed at 12 hours after hypoxia in hEPCs and 12, 36, 72 hours of hypoxia in HUVECs. The expression patterns of the TRx system components showed correlation with EC apoptosis and cell survival markers.ConclusionHypoxia induced significant apoptosis and its related active changes of the TRx system were evident in human EC lines. If the cellular impact of TRx expression pattern in various cardiovascular tissues under hypoxia or oxidative stress was studied meticulously, the TRx system could be applied as a new therapeutic target in cardiovascular diseases, such as ischemic heart disease or atherosclerosis.

The Interaction Between Redox and Hypoxic Signalling Pathways in the Dynamic Oxygen Environment of Cancer Cells

“…Upon growth in hypoxia cellular viability decreases, while after reoxygenation cell viability returns to levels consistent with those of cells grown in normoxia. A decrease in cell viability following hypoxic growth has also been observed by other researchers using different cell lines [77,78].…”

“…A recent study showed a decrease in thioredoxin reductase protein levels under hypoxia [75]. Previously, it was reported that thioredoxin reductase was increased in human endothelial progenitor cells but not in human umbilical vein endothelial cells under hypoxia [78]. This conflicting data suggests that as with the variable ROS levels reported under hypoxia, expression of the thioredoxin system under hypoxia may depend on the specific cell line, oxygen levels or how samples are processed.…”

“…Thioredoxin protein levels were increased in A549 human lung cancer cells during growth in 0.05% oxygen [88] and in both human endothelial progenitor cells and human umbilical vein endothelial cells cultured in 1% oxygen [78], as assessed by Western blotting. Our work [68] showed a visible increase (by Western blotting) in thioredoxin levels in MDA-MB-231 cells cultured in 0.1% hypoxia, but this increase was not statistically significant.…”

The PPARγ Agonist Protects Cardiomyocytes from Oxidative Stress and ApoptosisviaThioredoxin Overexpression

“…Hence reperfusion therapy is the best therapy for myocardial infarction and the typical secondary myocardial damage with oxidative stress in vivo. [3][4][5] Myocardial ischemia/ reperfusion can change the redox status of CMCs, and provoke CMC apoptosis or necrosis related to severe oxidative stress. 6) Thus certain interventions with ROS scavengers or antioxidants have been found to be cardioprotective against reperfusion injury in ischemic heart disease models.…”

β-arrestin2 Affects Cardiac Progenitor Cell Survival through Cell Mobility and Tube Formation in Severe Hypoxia

“…The Western blot analysis was performed as previously described. 15) The membrane was incubated with primary antibody against total-extracellular signal-regulated kinase ( t -ERK), phosphorylated-extracellular signal-regulated kinase ( p -ERK), total-protein kinase-B ( t -Akt), phosphorylated-protein kinase-B ( p -Akt), β-catenin, glycogen synthase kinase-3β (GSK-3β) (1:1,000; Santa Cruz Biotechnology, Santa Cruz, CA, USA), β-arr1/2, β-arr2 (1:1,000; Cell Signaling Technology, Danvers, MA, USA), and β-actin (1:5,000; Santa Cruz Biotechnology) was used as a loading control. For chemiluminescence detection, we used the WEST-ZOL ® Plus (iNtRON Biotechnology, Seongnam, Korea), and Las-3000 (Fujifilm Holding Corporation, Tokyo, Japan).…”