[Hypoxia and its simulant CoCl(2) down-regulates Foxp3 expression independent from HIF-1alpha]

This study was purposed to investigate the expression of Jurkat cell Foxp3 in hypoxia condition and the role of HIF-1alpha in this process as well as to clarify the mechanism influencing function of regulatory T cells by hypoxia. The Jurkat cells were incubated with hypoxia (1% O(>2)) and its simulant CoCl(2) for different times (0, 6, 12, 24 hours), the viability was measured by trypan blue staining, the expression of HIF-1alpha was detected by Western blot, the expression of Foxp3 was detected by real-time PCR, the expressions of HIF-1alpha and Foxp3 were assayed after HIF-1alpha in Jurkat cells was inhibited by using RNA interference technique. The results indicated that after Jurkat cells were treated with hypoxia and its simulant CoCl(2), the significant accumulation of HIF-1alpha in cells appeared, but the expression of Foxp3 was obviously down-regulated; after expression of HIF-1alpha in Jurkat cells was inhibited by siRNA interference, the CoCl(2) still could down-regulate the expression of Foxp3. It is concluded that the hypoxia and its simulant CoCl(2) can obviously down-regulate the expression of Foxp3, but this process is independent from HIF-1alpha.