Overexpression of Selenoprotein H Reduces Ht22 Neuronal Cell Death after UVB Irradiation by Preventing Superoxide Formation

Selenoproteins have been shown to exhibit a variety of biological functions, including antioxidant functions, maintaining cellular redox balance, and heavy metal detoxification. UV irradiation-induced damage is partially mediated by increased oxygen radical production. The present study is designed to examine the antioxidative effects of human selenoprotein H (hSelH) after brief period of UVB irradiation on the murine hippocampal neuronal cell line Ht22. Ht22 cells were stably transfected with the hSelH gene or with MSCV empty vector and exposed to UVB irradiation with or without the presence of serum. The results showed that cell viability was significantly higher in hSelH-transfected cells compared to the MSCV vector-transfected cells after 24 h of recovery with or without the presence of serum in the media. Further studies revealed that while the number of superoxide anion (O2˙-) positive cells was increased following a 7 mJ/cm(2) of UVB irradiation and 5 h of recovery, overexpression of hSelH significantly reduced superoxide production. These results suggest that hSelH overexpression protects cells from UVB irradiation-induced cell death by reducing the O2˙- formation.