Obesity impacts placental function through activation of p-IRE1a-XBP1s signaling

Figures

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  FIGURE 1. Maternal obesity induces IRE1α phosphorylation in the placenta. Placenta FFPE sections were labeled with anti-p-IRE1α specific antibody in the non-obese group (A), n = 10) and the obese group (B), n = 12). The labeling intensity was semi-quantified with ImageJ (C), showing the increased p-IRE1α in the obese placenta. Non-parametric Mann-Whitney U-test with p < 0.05 indicates a significant difference in p-IRE1α between the non-obese group to the obese group. Values are mean ± SEM. N1-N12: non-obese samples; O1-O12: obese samples.

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  FIGURE 2. Obesity activates XBP1 splicing in the placenta. XBP1s specific antibody was used to label activated XBP1s. Compared to the non-obese placenta (A), n = 10), the obese placenta exhibited increased XBP1s (B), n = 12). Elevated XBP1s was visualized by PCR with a primer pair flanking splicing regions followed by electrophoresis (C) (unspliced, 256 bp; spliced XBP1, 230 bp) (Yoon et al., 2019). Quantified with ImageJ on the immunocytochemically labeled sections (D) or XBP1s PCR gel images (E) showed increased XBP1s in the obese placenta. Furthermore, Reverse Transcription (RT)-QPCR demonstrated increase of XBP1s in the obese placenta (F). Non-parametric Mann-Whitney U-test was used to compare the XBP1s between the non-obese and obese placenta. Values are mean ± SEM. N1-N12: non-obese samples; O1-O12: obese samples.

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  FIGURE 3. Obesity does not activate Perk signaling and BiP in the placenta. p-Perk was at similar levels in the non-obese (n = 12) and obese placenta (n = 12). Four representative p-Perk labeled images from either non-obese or obese were showed (A). One of the chaperone gene, BiP, were at similar intensity in the non-obese and obese placenta (non-obese, n = 10; obese, n = 12). (B), Four representative BiP labeled images were shown from each group. Quantification of p-Perk (C) or BiP (D) labeling was performed with ImageJ. Non-parametric Mann-Whitney U-test was used to compare the controls to others. Values are mean ± SEM.

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  FIGURE 4. CHOP and UPR chaperones were upregulated in the placenta of obese pregnancy. CHOP was upregulated in obese placenta. Nine out of ten UPR chaperone genes we assessed with RT-QPCR were upregulated in the obese placenta. Non-parametric Mann-Whitney U-test was used to compare the chaperone gene expression in the non-obese placenta with the obese placenta, and p < 0.05 is considered significance. For non-obese group, n = 12; for obese group, n = 11. Values are mean ± SEM.