Placental Proteomics Reveal Insights into Fetal Alcohol Spectrum Disorders

Abstract

Background Fetal alcohol spectrum disorders (FASD) describe many of the well-known neurodevelopmental deficits afflicting children exposed to alcohol in utero. The effects of alcohol on the maternal-fetal interface, especially the placenta, have been less explored. We herein hypothesized that chronic binge alcohol exposure during pregnancy significantly alters the placental protein profile in a rat FASD model. Methods Pregnant rats were orogastrically treated daily with alcohol (4.5 g/kg, gestational day (GD) 5–10; 6.0 g/kg, GD 11–19) or 50% maltose dextrin (isocalorically matched pair-fed controls). On GD 20, placentae were collected, flash frozen, and stored until tissues were homogenized. Protein lysates were denatured, reduced, captured on a 10 kDa spin filter and digested. Peptides were eluted, reconstituted, and analyzed by a Q Exactive™ Hybrid Quadrupole-Orbitrap™ mass spectrometer. Results Mass spectrometry analysis identified 2,285 placental proteins based on normalized spectral counts and 2000 proteins by intensity based absolute quantification. 45 placental proteins were significantly (P<0.05) altered by gestational alcohol exposure by both quantification approaches. These included proteins directly related to alcohol metabolism; specific isoforms of alcohol dehydrogenase and aldehyde dehydrogenase were upregulated in the alcohol group. Ingenuity analysis identified ethanol degradation as the most significantly altered canonical pathway in placenta, and fetal/organ development as most altered function, with increased risk for metabolic, neurological, and cardiovascular diseases. Physiologic roles of the significantly altered proteins were related to early pregnancy adaptations, implantation, gestational diseases, fetal organ development, neurodevelopment, and immune functions. Conclusions We conclude that the placenta is a valuable organ not only to understand FASD etiology but it may also serve as a diagnostic tool to identify novel biomarkers for detecting the outcome of fetal alcohol exposure. Placental mass spectrometry analysis can offer sophisticated insights into identifying alcohol metabolism-related enzymes and regulators of fetal development.

An interaction between fetal sex and placental weight and efficiency predicts intrauterine growth in response to maternal protein insufficiency and gestational exposure window in a mouse model of FASD

“…Our study addresses this knowledge gap and provides important insights into the candidate mechanisms that may be responsible for the wide range of growth patterns observed in children affected with FASD. Because our findings identify the placenta as being one major determinant of fetal growth, molecular analyses of the placenta, such as the proteomic approach employed by Davis-Anderson and colleagues [46], are warranted to provide further understanding on how it contributes to the growth deficits accompanying these common stressors in human pregnancy.…”

Ethanol-Induced Alterations in Placental and Fetal Cerebrocortical Annexin-A4 and Cerebral Cavernous Malformation Protein 3 Are Associated With Reductions in Fetal Cortical VEGF Receptor Binding and Microvascular Density

“…Further, the reductions in fetal cortical CCM-3 expression are associated with the effects ethanol exposure on VEGF receptor expression and microvascular density and organization in fetal cerebral cortex ( Figures 5C, 6D,E). It is noteworthy that these three proteins were not identified in previous high-throughput screening surveys of proteins altered by PAE (Datta et al, 2008;Ramadoss and Magness, 2012;Davis-Anderson et al, 2017). These differential outcomes may be due to differences in animal models of PAE, particularly in dosing or patterns of alcohol exposure.…”

“…Over the past decade, one experimental approach to address this challenge has been to identify novel biochemical species in biomarker tissues that are altered as a consequence of alcohol consumption during pregnancy. Various biochemical species and processes have been examined, some using high throughput screening procedures such as DNA methylation (Lussier et al, 2018), mRNA expression profiles (Rosenberg et al, 2010;Downing et al, 2012;Carter et al, 2018), miRNA expression profiles (Balaraman et al, 2014(Balaraman et al, , 2016Gardiner et al, 2016) and proteomic approaches (Datta et al, 2008;Ramadoss and Magness, 2012;Davis-Anderson et al, 2017). While these approaches have identified a large array of novel targets affected by drinking during pregnancy, to date, there have been very few efforts to link these PAE-induced alterations in a biomarker to specific downstream consequences in brain that could be directly associated with altered neurodevelopment and adverse behavioral consequences.…”

The impact of tobacco chemicals and nicotine on placental development

“…The placenta is a portal and reservoir for a number of congenital viruses which do not result in evident gross placental inflammation, such as we and others demonstrated with Zika virus. [36][37][38] Maternal obesity, 39,40 gestational diabetes, 41 and alcohol consumption 42,43 are associated with highly predictive changes in the placenta. Levels of polycyclic aromatic hydrocarbons, a carcinogenic and toxic component of tobacco smoke, have been measured from the placenta in a study of preterm birth.…”