15 - Understanding the Role of Iron Regulation in Human Uterine Stromal Cells

Poster Board Number: 15
There are separate poster presentation times for odd and even posters.
Odd poster #s – first hour
Even poster #s – second hour

Co-authors:

Peeyush Lala - Anatomy and Cell Biology - University of Western Ontario; Stephen Renaud - Associate Professor, Anatomy and Cell Biology, University of Western Ontario

Abstract Body : Introduction
The development of an embryo requires a healthy decidual environment. Decidualization is the differentiation of fibroblast-like endometrial stromal cells (ESCs) into epithelioid and secretory-type decidual cells under the influence of progesterone, sustained during pregnancy. Iron is an essential nutrient that regulates many cellular processes, and adequate iron intake is particularly essential for a healthy pregnancy. Iron deficiency and overload are both implicated in adverse pregnancy outcomes, but the effects of these conditions on the decidualization of ESCs are not well understood. Therefore, our goal is to expose ESCs to iron overload or deficiency conditions to determine the effects on their capacity to decidualize.


Hypothesis
We hypothesize that decidualization will be impaired when ESCs are exposed to iron-deficient conditions and increased when exposed to iron-overload conditions.

Methods
Transformed human ESCs (THESCs) were maintained in non-decidualizing conditions (control) or exposed to 8-bromo-cAMP and medroxyprogesterone acetate for up to 8 days to induce decidualization. To simulate iron-deficiency and iron-overload conditions, cells were exposed to the iron chelator deferoxamine (DFO; 1mM) and ferric nitrate (FN; 2 mM) respectively. The extent of iron accumulation in cells was evaluated by western blotting for Ferritin. The extent of decidualization was determined using morphological characteristics and expression of decidualization markers: Insulin-like growth factor binding protein-1 (IGFBP-1) and Prolactin (PRL) using quantitative RT-PCR. Data was analyzed using ANOVA followed by Holm-Sidak’s multiple comparison test with P< 0.05 considered significant.



Results
Following exposure to decidualization conditions, THESCs showed an increased expression of decidualization markers: IGFBP-1 and PRL (all P< 0.05) as well as morphological changes from elongated fibroblast-like cells into large polygonal cells (n=3, p< 0.05). As expected, Ferritin levels were increased in cells following exposure to FN and decreased in DFO. Both iron overload and iron-deficient conditions impaired decidualization as evidenced by 30% and 35% decreased expressions of IGFBP-1 and PRL.


Discussion and Significance
These results suggest that too much or too little iron availability may compromise proper decidualization, which could contribute to the high incidence of adverse pregnancy outcomes associated with these conditions, such as infertility and spontaneous pregnancy loss. This allows us to revise our hypothesis that both iron overload and deficient conditions lead to impaired decidualization.

This work was funded by Canadian Institutes of Health Research and Natural Sciences and Engineering Research Council grants.