Ethanol Impairs NRF2/Antioxidant and Growth Signaling in the Intact Placenta In Vivo and in Human Trophoblasts

Abstract

NRF2 is a redox-sensitive transcription factor that depending on the duration or magnitude of the stress, either translocates to the nucleus (beneficial) or is degraded in the cytosol (harmful). However, the role of NRF2-based mechanism(s) under ethanol (E)-induced developmental toxicity in the placental context remains unknown. Here, we used a rat prenatal model of maternal alcohol stress consisting of intermittent ethanol vapor (IEV) daily from GD11 to GD20 with a 6 h ON/18 h OFF in a vapor chamber and in vitro placental model consisting of HTR-8 trophoblasts exposed to 86 mM of E for either 24 h or 48 h. The role of NRF2 was evaluated through the NRF2-transactivation reporter assay, qRT-PCR, and Western blotting for NRF2 and cell growth-promoting protein, and cell proliferation assay. In utero and in vitro E decreased the nuclear NRF2 content and diminished its transactivation ability along with dysregulation of the proliferation indices, PCNA, CYCLIN-D1, and p21. This was associated with a ~50% reduction in cell proliferation in vitro in trophoblasts. Interestingly, this was found to be partially rescued by ectopic Nrf2 overexpression. These results indicate that ethanol-induced dysregulation of NRF2 coordinately regulates PCNA/CYCLIN-D1/p21 involving growth network, at least partially to set a stage for placental perturbations.

Epigallocatechin Gallate Ameliorates the Effects of Prenatal Alcohol Exposure in a Fetal Alcohol Spectrum Disorder-Like Mouse Model

“…As previously mentioned, PAE boosts the production of ROS and the dysregulation of the antioxidant systems, being one of the leading causes of FASD physiopathology [ 17 ]. Under oxidative stress conditions, Nrf2 is released from its inhibitor Keap-1, translocated from the cytoplasm to the nucleus where it triggers the expression of genes encoding antioxidant proteins and detoxifying enzymes as catalase, superoxide dismutase, and the glutathione peroxidase families [ 39 ] by binding to the antioxidant responsive elements located in the promoter region of these detoxifying enzymes.…”

“…Thus, PAE affects the central nervous system in all stages of brain development (neurulation, proliferation, migration, differentiation, synaptogenesis, gliogenesis, myelination, apoptosis, and plasticity) through a variety of mechanisms that include oxidative stress and the direct alteration of the epigenetic pattern in the neural lineages [ 11 , 12 ]. Therefore, ethanol may alter the expression of a wide range of neural biomarkers, e.g., the neuronal nuclear antigen (NeuN) [ 13 ], doublecortin (DCX) [ 14 ], glial fibrillary acidic protein (GFAP) [ 15 ], and the brain-derived neurotrophic factor (BDNF) [ 16 ], as well as of the oxidative stress biomarkers, e.g., the nuclear factor erythroid 2-related factor 2 (Nrf2) [ 17 ].…”

The effect of ethanol and nicotine on ER stress in human placental villous explants

“… Chen et al (2020) used several nicotine concentrations (0.1–10 µM) at three time points, that did not cause cell death in HTR-8/SVneo cells supporting our viability results. However, a two times higher concentration of ethanol (4 mg/ml), compared to the one used in this study (2‰ that equals to 2 mg/ml), has been shown to cause cell death in HTR-8/SVneo cells at 48 h ( Shanmugam et al, 2019 ). Based on the viability studies and our previous studies in BeWo cells, the used concentrations of nicotine and ethanol were considered relevant and not affecting the molecular markers studied in the explants.…”

Translation suppression underlies the restrained COVID-19 mRNA vaccine response in the high-risk immunocompromised group

“…The thermal cycling conditions used include 50°C/2 min; 95°C/10 min followed by 40 PCR cycles at 95°C/15 sec and 60°C/1 min. Relative expression was quantified using Ct values, and expression fold-change was calculated by normalization to the Ct of the housekeeping gene, β-actin, according to the 2 -ΔΔCt methods ( 29 , 30 ).…”