The role of O-GlcNAcylation in trophoblast and its contribution to placental dysfunction

Paijens, S. (Sterre) (2014) The role of O-GlcNAcylation in trophoblast and its contribution to placental dysfunction. thesis, Medicine.

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Abstract

The role of O-GlcNAcylation in trophoblast and its contribution to hyperglycemia-induced placental dysfunction The prevalence of gestational diabetes mellitus and obesity during pregnancy keeps increasing. Gestational diabetes mellitus creates a hyperglycemic intrauterine environment, which increases flux through the hexosamine biosynthesis pathway. This is expected to enhance protein O-GlcNAcylation in trophoblast. We hypothesise that in turn this may contribute to placental dysfunction and predisposition to chronic conditions including obesity, diabetes mellitus, cancer and cardiovascular diseases. In this project we aim to investigate the O-GlcNAcylation of Specific protein 1 (Sp1), a known O-GlcNAcylated protein present in trophoblast, and the effect of O-GlcNAcylation on trophoblast function. BeWo cells were treated with a specific substrate of the hexosamine biosynthesis pathway, D-glucosamine at a range of doses (0-5.0mM) for time points up to 48 hours to investigate whether Sp1 is O-GlcNAcylated in trophoblast. This was monitored by immunofluorescence staining and Western blotting. The influence of altered O-GlcNAcylation levels on cell proliferation was researched by analyzing total cell number after glucosamine treatments (0-10mM) for 24 and 48 hours. To see whether this effect was lasting BeWo cells were treated with glucosamine (0, 2.5m and 5.0mM) for 24 or 48 hours, and then changed back to non-glucosamine containing medium. The effect was monitored by counting total cell number, using the hemocytometer, directly after the medium change, and at 24 and 48hours after the medium change. Finally we looked at the influence of glucosamine treatments on leptin production in BeWo cells by performing a leptin ELISA on cell culture supernatant of glucosamine treated (0-2.5mM) BeWo cells was collected at 72 hours. Results show that O-GlcNAc modification occurs within in the placenta. No substantial evidence is found that specific protein is O-GlcNAcylated, however abundance seems to increase with increasing glucosamine treatments. Cell proliferation is significantly decreased with increasing glucosamine treatments (P<0.0001). However, the cells seem to be able to recover from glucosamine treatments even if harsh and for a longer time of exposure since differences in total cell number where no longer significant. Finally leptin production has shown to decrease with increasing glucosamine treatments (P=0.0258). O-GlcNacylation is an abundant modification in the placenta, which potentially affects Sp1 abundance and functioning. Also it has an effect on trophoblast functions like proliferation, survival and leptin production. These alterations may be involved in inducing placental dysfunction or inducing a predisposition to chronic disease, therefore it is important to further investigate these matters to get better insight on the mechanism behind this phenomenon.

Item Type:	Thesis (Thesis)
Supervisor name:	Scherjon, Prof. Dr. S.A. and Oosterveer, Dr. M.
Supervisor name:	Aplin, Professor Dr. J.D. and Westwood, Dr. M. and St. Mary’s hospital and Manchester, England
Faculty:	Medical Sciences
Date Deposited:	25 Jun 2020 10:46
Last Modified:	25 Jun 2020 10:46
URI:	https://umcg.studenttheses.ub.rug.nl/id/eprint/761

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