The roles of pyruvate in anti-oxidation in HEK 293 cells
Date Issued
2012
Date
2012
Author(s)
Lai, Yong-Tzuo
Abstract
Ischemia/reperfusion is a pathophysiological condition of which blood flow is blocked and then restored. It will cause profound pathological effects such as oxidative stress caused by the mitochondria dysfunction. In some animal models, supplement of pyruvate effectively mitigates ischemia/reperfusion injury. There is growing evidence that some metabolites may play a new role as a signaling messenger and regulate the function of proteins in addition to their traditional roles of energy supplement and biosynthesis. To verify this, our laboratory developed a method for identification of pyruvate-interacting proteome (AETHIC). And the purpose of this study is to investigate the role of pyruvate in counteracting oxidative stress. According to AETHIC and metabolome results, we focused on citrate synthase and thioredoxin reductase (TrxR). The former enzyme and NADP+-dependent isocitrate dehydrogenase (NADP+-IDH) contribute a pathway of NADPH production, and the latter, TrxR, is directly associated with anti-oxidative function.
The flux of TCA cycle, NADPH/NADP+ and NADH/NAD+ increased after addition of pyruvate to HEK cell. Also, the activity of citrate synthase decreased under the same treatment, which indicates the regulatory role of pyruvate in TCA cycle. Next, I measured the activity of NADP+-IDH and found that pyruvate increased the activity of IDH in vitro but was less effective in cellulo. The activity of TrxR was significantly decreased under H2O2 treatment, but pyruvate completely recovered the activity to normal levels. Consequently, it is suggested that pyruvate may protect TrxR and restore its activity under oxidative stress.
Above all, pyruvate rescue cells from oxidative stress by elevation of the reducing power of cells and sustaining the TrxR/Trx system.
Subjects
Ischemia/reperfusion
pyruvate
citrate synthase
NADP+-dependent isocitrate dehydrogenase
thioredoxin reductase
Type
thesis
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