Analysis of gene expression in human umbilical vein endothelial cells exposed to a 50-Hz magnetic field

Human umbilical vein endothelial cells (HUVECs) were exposed to 100-μT, 50-Hz sinusoidal intermittent (5 min off, 10 min on) magnetic fields for 24 h. Total RNA was extracted from exposed and sham-exposed cells and was then analyzed via a DNA microarray technique. Interestingly, the expression of a subunit of the L-type Ca channel was 2.3-fold higher in exposed cells; this finding may be relevant to similar previously published results (an increase of α1C and α1D subunits of L-type Ca channel in neuronal stem cells as preveiously demonstrated by Piacentini and colleagues in 2008. However, analysis of the false discovery rate precluded us from drawing firm conclusions about the effects of magnetic fields on gene expression in HUVECs. Nevertheless, non-coding RNAs were more common than coding RNAs among the genes that were differentially expressed with a > 2-fold or < 0.5-fold difference between exposed and sham-exposed cells. A similar result was obtained when the expression data from exposed cells or those from sham-exposed cells were analyzed separately. Thus, the higher frequency of non-coding RNAs than that of coding RNAs among the differentially expressed genes was attributed to the higher degree of fluctuation in the expression of non-coding RNA. Interestingly, this fluctuation seems to be a characteristic intrinsic to non-coding RNAs themselves.