ERβ modulation and non-modulation of ERα by administration of geniposide and panax notoginseng saponins in SH-SY5Y cells

Abstract

To illustrate the effect of geniposide (GP) and panax notoginseng saponins (PNS) on estrogen receptors (ER) including ERα and ERβ within the cytoplasm and nucleus of SH-SY5Y cells. Immunofluorescence was used to observe the distribution of ERα and ERβ in cytoplasm and nucleus, but Western blot was only for ERβ detection. q-PCR was applied to detect NR3C1, S100A6 and LGALS1downstream mRNA gene expression levels of ER. Through analyzing fluorescence intensity under the administration of GP and PNS in SH-SY5Y cells, we found that the distribution of ERα has not been affected. We also discovered that GP and/or PNS significantly stimulated the transportation of ERβ into the nucleus in a time-dependent manner (all P < .001). When SH-SY5Y cells were treated with supplements of GP, PNS, GP + PNS at 15 minutes, 30 minutes and 45 minutes, the distribution of ERβ in the nucleus significantly increased compared with that in control group (all P < .001). Evidently, treatment with GP, PNS, GP + PNS was able to significantly increase the levels of ERβ protein within the nucleus compared with control group at both 30 minutes and 45 minutes intervals (all P < .001). Furthermore, GP and PNS showed signs of activating to NR3C1 and LGALS1, two genes downstream of ER. It is possible that the S100A6 gene mainly encoded the downstream gene in ERα's signaling pathway, which was not affected after the treatment of GP and/or PNS. The distribution and expression of ERβ has been modulated under the administration of GP + PNS within the SH-SY5Y cells, whereas ERα has not. GP and PNS in combination may play an estrogenic-like effect with selectivity on ERβ modulation.