Abstract (eng)
The transcription factor HIF-1α is well known to respond to alterations in oxygen availability in cells [SEMENZA, 2003] and there is strong evidence for plaque hypoxia
[SILVOLA et al., 2011]. It is known from the literature that biologically active gases such as H2S [BUDDE and ROTH, 2010] and NO [BERCHNER-PFANNSCHMIDT et al., 2010] can influence the activity of HIF-1α.
In the present work, we investigated the role of H2S and NO on the expression of HIF-1α protein under different oxygen conditions in THP-1 macrophages. We compared the effect of the fast-releasing H2S donor, NaHS and the slow-releasing H2S donor, GYY4137on HIF-1α protein in THP-1 macrophages. These donors release H2S at different rates and therefore give rise to different concentrations of the gas over different time periods The influence of NO generated by DETA-NO on THP-1 macrophages was also investigated. Furthermore, oxidative stress was examined in cells after the use of different H2S releasers.
Increased HIF-1α protein levels in macrophages due to hypoxia were confirmed in this work. We observed an accumulation of HIF-1α protein when cells were under hypoxia for 4 hours leading to an up to 150-fold enrichment compared with cells incubated under normoxia. There was an important difference in the effect of the two H2S donors on the HIF-1α protein levels of cultured macrophages. Treatment of THP-1 cells with NaHS caused no effect on the amount of HIF-1α protein, whereby administraton of GYY4137 decreased HIF-1α protein under hypoxia concentration dependently.
DETA-NO showed an increase of HIF-1α independent from oxygen conditions.
We monitored several effects of the H2S donors on DCF-fluorescence in THP-1 macrophages. It seems that different methods led to different results, and we cannot make a clear statement concerning pro- or antioxidative properties of NaHS and GYY4137.