Different regulation of IRE1α and eIF2α pathways by oxygen and insulin in ACH-3P trophoblast model

in Reproduction
View More View Less
  • 1 V Tandl, Department of Obstetrics and Gynecology, Medical University of Graz, Graz, Austria
  • 2 D Hoch, Department of Obstetrics and Gynecology, Medical University of Graz, Graz, Austria
  • 3 J Bandres-Meriz, Department of Obstetrics and Gynecology, Medical University of Graz, Graz, Austria
  • 4 S Nikodijevic, Department of Obstetrics and Gynecology, Medical University of Graz, Graz, Austria
  • 5 G Desoye, Department of Obstetrics and Gynecology, Medical University of Graz, Graz, Austria
  • 6 A Majali-Martinez, Department of Obstetrics and Gynecology, Medical University of Graz, Graz, Austria

Correspondence: Gernot Desoye, Email: gernot.desoye@medunigraz.at
Restricted access

Endoplasmic reticulum (ER)-stress activates the unfolded protein response (UPR), which plays a (patho)physiological role in the placenta. Oxygen and hyperinsulinemia are major regulators of placental development. Thus, we hypothesized that oxygen, insulin and their interplay modulate ER-stress in early pregnancy. Using the human first trimester trophoblast cell line ACH-3P, we quantified mRNA and protein of several members of UPR by RT-qPCR and Western blotting, respectively. ER-stress induction using tunicamycin and brefeldin A resulted in increased CHOP (4.6-fold change; P ≤ 0.001), XBP1 expression (1.7- and 1.3-fold change, respectively; P ≤ 0.001 and P < 0.05) and XBP1 splicing (7.9- and 12.8-fold change, respectively; P ≤ 0.001). We subsequently analyzed the effect of oxygen (6.5%, 2.5%), insulin (0.1-10 nM) and their interaction using ANCOVA adjusted for cell passage as co-variate. Although GRP78 protein remained unaffected, low oxygen (2.5% O2) increased IRE1α phosphorylation (+52%; P < 0.05) and XBP1 splicing (1.8-fold change; P ≤ 0.001) after 24h, while eIF2α protein and CHOP expression were downregulated (–28%; P < 0.05 and –24%; P ≤ 0.001; respectively). eIF2α phosphorylation was also reduced after 48h by low oxygen (–61%; P < 0.05), but increased in the presence of insulin (+46%; P ≤ 0.01). These changes were not PERK-mediated, since PERK phosphorylation and total protein were not altered. Overall, our results suggest that IRE1α and eIF2α UPR-pathways are differentially regulated by oxygen and insulin in early pregnancy.

 

     An official journal of

    Society for Reproduction and Fertility

 

Sept 2018 onwards Past Year Past 30 Days
Abstract Views 165 165 165
Full Text Views 4 4 4
PDF Downloads 6 6 6