In vitro fertilization causes excessive glycogen accumulation in mouse placenta

Comparative Proteomic and Phospho-proteomic Analysis of Mouse Placentas Generated via In Vivo and In Vitro Fertilization

Offspring conceived by assisted reproductive technologies (ART) have increased risk of suffering from gestational complications, and placental dysfunction is related with the adverse outcomes. Studies have revealed that abnormal or adaptive changes can occur in ART placentas, but the potential reasons are not fully understood. Hereby, we tried to use proteomics and phospho-proteomics to find the underlying mechanisms responsible for the changes of ART placentas. Liquid chromatography-tandem mass spectrometry was utilized to perform proteome and phospho-proteome detection on mouse placentas. The differential expressed proteins (DEPs) or phospho-proteins (DEPPs) were analyzed based on subcellular localization, functional classification, and enrichment. Western blot was used to verify the DEPs (Afadin, ZO-1, Ace2, Agt, Slc7a5, and Slc38a10) and measure mTOR signaling activities (mTOR, Rps6, and 4Ebp1). The data showed that 161 DEPs and 304 DEPPs were found in proteome and phospho-proteome, respectively. Multiple biological processes were enriched based on those DEPs and DEPPs, and renin-angiotensin system, cell junction, and PI3K-Akt pathway were investigated. By protein expression identification, two key proteins associated with renin-angiotensin system (Ace2 and Agt) were down-regulated, and the levels of Afadin and ZO-1 (related with cell junction) as well as Slc38a10 were increased in IVF placentas. In addition, mTOR downstream activities were increased as shown by p-Rps6 and p-4Ebp1 in IVF placentas. In conclusion, IVF leads to the changes of cell junction, renin-angiotensin system, amino acid transport, and increased mTOR signaling in mouse placentas, which may be associated with the altered structure and function of IVF placentas.

Preconception paternal alcohol exposure decreases IVF embryo survival and pregnancy success rates in a mouse model

Increasingly, couples struggling with fertility turn to assisted reproductive techniques, including IVF, to have children. Despite the demonstrated influence of periconception male health and lifestyle choices on offspring development, studies examining IVF success rates and child health outcomes remain exclusively focused on maternal factors. Using a physiologically relevant mouse model, we tested the hypothesis that chronic paternal preconception alcohol intake adversely affects IVF success and negatively impacts IVF offspring fetoplacental growth. Using a voluntary, binge-like mouse model, we exposed sexually mature C57BL/6J males to three preconception treatments (0% (Control), 6% EtOH or 10% EtOH) for 6 weeks, isolated and cryopreserved caudal sperm from treated males, and then used these samples to fertilize oocytes before assessing IVF embryo developmental outcomes. We found that preconception paternal alcohol use reduced IVF embryo survival and pregnancy success rates in a dose-dependent manner, with the pregnancy success rate of the 10% EtOH treatment falling to half those of the Controls. Mechanistically, we found that preconception paternal alcohol exposure disrupts embryonic gene expression, including Fgf4 and Egfr, two critical regulators of trophectoderm stem cell growth and placental patterning, with lasting impacts on the histological organization of the late-term placenta. The changes in placental histoarchitecture were accompanied by altered regulation of pathways controlling mitochondrial function, oxidative phosphorylation and some imprinted genes. Our studies indicate that male alcohol use may significantly impede IVF success rates, increasing the couple's financial burden and emotional stress, and highlights the need to expand prepregnancy messaging to emphasize the reproductive dangers of alcohol use by both parents.

Paternal epigenetic influences on placental health and their impacts on offspring development and disease

Our efforts to understand the developmental origins of birth defects and disease have primarily focused on maternal exposures and intrauterine stressors. Recently, research into non-genomic mechanisms of inheritance has led to the recognition that epigenetic factors carried in sperm also significantly impact the health of future generations. However, although researchers have described a range of potential epigenetic signals transmitted through sperm, we have yet to obtain a mechanistic understanding of how these paternally-inherited factors influence offspring development and modify life-long health. In this endeavor, the emerging influence of the paternal epigenetic program on placental development, patterning, and function may help explain how a diverse range of male exposures induce comparable intergenerational effects on offspring health. During pregnancy, the placenta serves as the dynamic interface between mother and fetus, regulating nutrient, oxygen, and waste exchange and coordinating fetal growth and maturation. Studies examining intrauterine maternal stressors routinely describe alterations in placental growth, histological organization, and glycogen content, which correlate with well-described influences on infant health and adult onset of disease. Significantly, the emergence of similar phenotypes in models examining preconception male exposures indicates that paternal stressors transmit an epigenetic memory to their offspring that also negatively impacts placental function. Like maternal models, paternally programmed placental dysfunction exerts life-long consequences on offspring health, particularly metabolic function. Here, focusing primarily on rodent models, we review the literature and discuss the influences of preconception male health and exposure history on placental growth and patterning. We emphasize the emergence of common placental phenotypes shared between models examining preconception male and intrauterine stressors but note that the direction of change frequently differs between maternal and paternal exposures. We posit that alterations in placental growth, histological organization, and glycogen content broadly serve as reliable markers of altered paternal developmental programming, predicting the emergence of structural and metabolic defects in the offspring. Finally, we suggest the existence of an unrecognized developmental axis between the male germline and the extraembryonic lineages that may have evolved to enhance fetal adaptation.