Glycosylation Profile of the Transferrin Receptor in Gestational Iron Deficiency and Early-Onset Severe Preeclampsia

Abstract

Objective: To examine the expression of hypoxia-inducible factor-1α (HIF-1α), TfR1, and TfR1-attached terminal monosaccharides in placentas of women with IDAP and severe preeclampsia.

Methods: TfR1 and HIF-1α were detected by western blot. Immunoadsorption of TfR1 was performed to characterize the terminal monosaccharides by specific lectin binding.

Results: There was no difference in the expression of TfR1 and HIF-1α between groups. Lectin blot analysis pointed out an overexpression of galactose β1-4 N-acetylglucosamine (Gal-GlcNAc) and mannose in severe preeclampsia.

Conclusion: The increase in Gal-GlcNAc may be due to the increased presence of antennary structures and the mannose glycans of TfR1 may indicate the presence of misfolded or incomplete proteins. These findings may be associated with the low expression of placental TfR1 in women with preeclampsia.

Figure 1

TfR1 expression in placental villi. (a) Representative image of a Western blot (an entire picture is presented in the supplementary figure 4A). (b) Expression of TfR1 in trophoblastic villi in the control group (C) n=5, the group with IDAP (A) n=5 and the group with early-onset severe preeclampsia (PE) n=6. No statistically significant difference in protein expression in the three groups of women was detected. The data are shown expressed as median and range, Kruskal-Wallis statistical analysis.

Figure 2

HIF-1α expression in placental villi. (a) Representative image of a Western blot (an entire picture is presented in the supplementary figure 4B). (b) Expression of HIF-1α in trophoblastic villi in the control group (C) n=5, the group with IDAP (A) n= 5 and the group with early-onset severe preeclampsia (PE) n=6. No statistically significant difference in protein expression between the three groups of women was observed. The data are shown as median and range, Kruskal-Wallis statistical analysis.

Figure 3

Expression pattern Gal-GlcNAc detected by the DSA lectin. (a) Representative image of a lectin blot; as positive control fetuin was used and as negative control carboxypeptidase Y (CB.Y). (b) Expression of the Gal-GlcNAc pattern of TfR1 in trophoblastic villi in the control group (C), the group with IDAP (A), and the group with early-onset severe preeclampsia (PE). The data are presented as median and range, Kruskal-Wallis statistical analysis, where p <0.05 ∗.

Figure 4

Expression pattern of mannose detected by the GNA lectin. (a) Representative image of a lectin blot; as positive control carboxypeptidase Y (CB.Y) was used, and as negative control fetuin. (b) Expression of the mannose pattern of TfR1 in trophoblastic villi in the control group (C), the group with IDAP (A), and the group with early-onset severe preeclampsia (PE). The data are presented as median and range, Kruskal-Wallis statistical analysis, where p <0.05 ∗.