Effects Of Down-regulating Aquaporin-1 Expression On Apoptosis In Balb/c 3T3 Fibroblast

ObjectiveThe water transportation makes a great important role in cell normal metabolism.Aquaporins (AQPs) are small, integral membrane proteins. The aquaporins (AQPs) comprise a family of at least 10 highly conserved water channel proteins. Aquaporins-1(AQP1)play fundamental roles in water and osmolyte homeostasis by facilitating water and small solute movement across plasma membranes of epithelial, endothelial and other tissues. To clarify the function of AQP1 and mechanism invoved inα-toxin, we down-regulated AQP1 expression by RNAi technique to observe cellular apoptosis underα-toxin incubation.MethodsThe experiment was divided into three groups: normal cell group; control-RNAi group, in which the small interfering RNA was transfected into Balb/c 3T3 fibroblasts to target non-specifically mRNA; the AQP1-RNAi group, in which the small interfering RNA was transfected into Balb/c 3T3 fibrobalsts to target specifically mRNA for AQP1.Western blotting were used to analyze the AQP1 expression. After the cells was incubated withα-toxin for 4h, Flow cytometry was performed to analyze cell apoptosis. Microscope were used to analyze diversifies of cell morphology.ResultsCompared with the normal cell group, AQP1 was reduced by about 60.55 and 48.85 % in AQP1-RNAi group and control-RNAi group respectivelyWe found that apoptotic rate was 6.07% in normal cell group, 6.17% in control-RNAi group and 9.76% in AQP1-RNAi group. the cells became round up, pincher, and isolated to the other cells. But the AQP1-RNAi group's changes were more obviously than the other two groups.DiscussionAfter incubated withα-toxin for 4h, the apoptotic rate of AQP1-RNAi group was higher than normal cell group and control-RNAi group. This indicated that AQP1 may involved in apoptosis. It suggested that the influx of water may induced apoptosis underα-toxin incubation. Absence of AQP1 may inhibit the outflux of water, and the cells could not resist water flux that augmented apoptotic rate.ConclusionsDown-regulated AQP1 expression increased apoptosis induced byα-toxin, which indicated that AQP1 may involved in apoptosis.