Abstract P240: Higher Body Mass Index is Associated With Lower Placental Expression of EPYC: Results From a Genome-Wide Transcriptomic Study in the Gen3G Cohort

Background: Elevated maternal body mass index (BMI) in pregnancy is associated with adverse maternal and fetal outcomes. Identification of alterations in the placental transcriptome may elucidate molecular markers of the biological pathways underlying these associations.

Methods: We investigated the association of first trimester maternal BMI with the placental transcriptome in Gen3G, a large population-based pregnancy cohort. We completed RNA sequencing of 449 placental samples and performed differential gene expression analysis of over 15,000 genes (Limma Voom). We used maternal BMI as a continuous variable, with estimates reported as change in normalized gene expression per 1-unit increase in BMI (kg/m2), as well as a categorical variable (participants with normal weight (N=270) vs. obesity (N=82)), with RNA expression estimates reported as log2 fold changes. We adjusted models for maternal age, fetal sex, gestational age and 6 surrogate variables inferred from the expression data to adjust for batch effects and other unmeasured sources of variability. We accounted for multiple testing using False Discovery Rate (FDR). Sensitivity analyses were performed by removing cases of gestational diabetes and hypertensive disorders in pregnancy.

Results: At enrollment in early pregnancy, participants had a mean ± SD age of 28.2 ± 4.4 years and measured BMI of 25.4 ± 5.5 kg/m 2 ; 57% of participants were categorized in normal weight, 22% in overweight and 18% in obesity BMI categories. Maternal BMI was significantly associated with decreased expression of EPYC , a gene that regulates fibrillogenesis (slope= -0.14, FDR-adjusted P=1.68x10 -5 for continuous BMI; log2 fold change= -1.71, FDR-adjusted P=1.06x10 -2 for obesity vs. normal weight). Both sensitivity analyses with the removal of gestational diabetes and hypertensive disorders revealed similar associations for EPYC .

Conclusions: We identified an association between elevated maternal BMI and downregulation of EPYC expression in the placenta. Additional studies are required to examine the role of placental EPYC expression in maternal and fetal health.

Abstract P105: Redox Modulator Akt-1005 Alleviates Oxidant Stress In An In Vitro Model Of Preeclampsia

Background: Preeclampsia (PE) is a pregnancy-specific syndrome affecting 5-7% of all pregnant women, and there is no effective treatment available. Early abnormal placental development is associated with oxidative stress and the release of reactive oxygen species in the placenta. This phenomenon leads to downstream signaling and production of anti-angiogenic factors, which cause endothelial and trophoblast dysfunction and the cardinal features of PE, i.e., hypertension, proteinuria, and in severe cases, eclampsia. Our group developed a novel series of redox modulators and sought to test if these compounds can effectively reduce placental oxidative stress and mitigate PE symptoms in vitro .

Methods: We induced in vitro oxidant stress in human villous explants with 2% O 2 and assessed whether augmenting cell-redox function with the proposed compound AKT-1005 reduced (i) cell injury (cell cytotoxicity assay), (ii) mitochondrial stress (mitochondrial -derived superoxide production, mitochondria dysfunction) (iii) production of the transcription factor HIF1A and (iv) downstream anti-angiogenic responses (sFLT1 production). These effects were compared with reference antioxidants i.e., Vit C and MitoTEMPO.

Results: In our villous explant assays, pretreatment with the AKT-1005 reduced mitochondrial-derived ROS production in hypoxia-exposed trophoblasts cells, indicating that the key factor in the development of PE, the oxidant stress, can be alleviated by the redox modulator compound. The AKT-1005 pretreatment also reduced HIF-1A expression and sFLT1 protein expression in hypoxia-exposed villous trophoblast cell, with better efficacy than Vit C and MitoTempo. Furthermore, AKT-1005 improved the mitochondrial electron chain enzyme activity in the stressed explant culture, mainly in syncytiotrophoblast cells, which is another promising characteristic of the applied antioxidant molecule.

Conclusion: In reducing placental trophoblast oxidative stress, redox modulators present a potential novel therapeutic approach for the treatment of preeclampsia. Future investigation is warranted regarding the in vivo use of these compounds.