Figure 3 | Cell Death & Disease

Figure 3

From: Fluvoxamine alleviates ER stress via induction of Sigma-1 receptor

Figure 3

Flv induces Sig-1R expression without activating the unfolded protein response (UPR) during ER stress. (a) Flv (10 μg/ml) or tunicamycin (Tm; 1 μg/ml) was added to Neuro2a cells, and changes in ATF6α processing were monitored over the time course shown in the figure. The amount of processed ATF6α protein increased with Tm treatment but not with Flv treatment. Processed ATF6α/total ATF6α was measured with densitometry. The results are shown in the bar graph. The 0 h time point was normalized to 1. Values are the mean±S.D. (*P<0.05, Student’s t-test; n=3). (b) Flv (10 μg/ml) or Tm (1 μg/ml) was added to Neuro2a cells, and changes in XBP-1 splicing were measured by semiquantitative RT-PCR over the time course shown in the figure. XBP-1 splicing was observed with Tm treatment but not with Flv treatment. (c) Flv (10 μg/ml) was added to Neuro2a cells, and changes in the expression of GRP78/BiP and GRP94, which react with anti-KDEL antibodies, were monitored over the time course shown in the figure. No change in the expression of GRP78/BiP or GRP94 as a result of Flv treatment was observed. (d) Flv (10 μg/ml) was added to Neuro2a cells, and the expression of total eIF2α and phosphorylated eIF2α was measured over the time course shown in the figure. No change in the amount of total eIF2α (w-eIF2α) or phosphorylated eIF2α (p-eIF2α) as a result of Flv treatment was observed. p-eIF2α/w-eIF2α was measured with densitometry. The results are shown in the bar graph. The 0 h time point was normalized to 1. Values are the mean±S.D. (*P<0.05, Student’s t-test; n=3). (e) Mouse embryonic fibroblasts (MEFs) from PERK wild-type (PERK+/+) and PERK knockout (PERK−/−) mice were treated with 10 μg/ml of Flv. The expression of Sig-1R and GAPDH was monitored over the time course shown in the figure. Flv treatment induced Sig-1R expression in MEFs from PERK+/+ and PERK−/− animals. (f) Densitometry analysis of (e) showed that relative intensity of Sig-1R/GAPDH increased significantly in both PERK+/+ and PERK−/− MEFs in response to Flv treatment. Left graph, PERK+/+ MEFs; right graph, PERK−/− MEFs. Values are the mean±S.D. (*P<0.05, Student’s t-test; n=3)

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