Ethanol-induced oxidative stress and mitochondrial dysfunction in rat placenta: relevance to pregnancy loss.

BACKGROUND: Ethanol consumption during pregnancy increases the risk of early pregnancy loss and causes intrauterine growth restriction. We previously showed that chronic gestational exposure to ethanol impairs placentation, and that this effect is associated with inhibition of insulin and insulin growth factor signaling. Since ethanol also causes oxidative stress and DNA damage, we extended our investigations to assess the role of these pathological processes on placentation and placental gene expression. METHODS: Pregnant Long Evans rats were pair-fed liquid diets containing 0% or 24% ethanol by caloric content. Placentas harvested on gestation day 16 were used to examine DNA damage, lipid peroxidation, apoptosis, mitochondrial gene/protein and hormonal gene expression in relation to ethanol exposure. RESULTS: Gestational exposure to ethanol increased fetal resorption, and trophoblast apoptosis/necrosis, oxidative stress, DNA damage, and lipid peroxidation. These adverse effects of ethanol were associated with increased expression of pro-apoptotic (Bax and Bak) and reduced levels of the anti-apoptotic Bcl-2 protein. In addition, increased trophoblast apoptosis proneness was associated with p53-independent activation of p21, reduced mitochondrial gene and protein expression, and dysregulated expression of prolactin (PRL) family hormones that are required for implantation and pregnancy-related adaptations. CONCLUSIONS: Chronic gestational exposure to ethanol increases fetal demise due to impaired survival and mitochondrial function, increased oxidative stress, DNA damage and lipid peroxidation, and dysregulated expression of prolactin family hormones in placental trophoblasts.

Expression profile of G-protein ßγ subunit gene transcripts in the mouse olfactory sensory epithelia.

Heterotrimeric G-proteins mediate a variety of cellular functions, including signal transduction in sensory neurons of the olfactory system. Whereas the Gα subunits in these neurons are well characterized, the gene transcript expression profile of Gßγ subunits is largely missing. Here we report our comprehensive expression analysis to identify Gß and Gγ subunit gene transcripts in the mouse main olfactory epithelium (MOE) and the vomeronasal organ (VNO). Our reverse transcriptase PCR (RT-PCR) and realtime qPCR analyses of all known Gß (ß1,2,3,4,5) and Gγ (γ1,2,2t,3,4,5,7,8,10,11,12,13) subunits indicate presence of multiple Gß and Gγ subunit gene transcripts in the MOE and the VNO at various expression levels. These results are supported by our RNA in situ hybridization (RISH) experiments, which reveal the expression patterns of two Gß subunits and four Gγ subunits in the MOE as well as one Gß and four Gγ subunits in the VNO. Using double-probe fluorescence RISH and line intensity scan analysis of the RISH signals of two dominant Gßγ subunits, we show that Gγ13 is expressed in mature olfactory sensory neurons (OSNs), while Gß1 is present in both mature and immature OSNs. Interestingly, we also found Gß1 to be the dominant Gß subunit in the VNO and present throughout the sensory epithelium. In contrast, we found diverse expression of Gγ subunit gene transcripts with Gγ2, Gγ3, and Gγ13 in the Gαi2-expressing neuronal population, while Gγ8 is expressed in both layers. Further, we determined the expression of these Gßγ gene transcripts in three post-natal developmental stages (p0, 7, and 14) and found their cell-type specific expression remains largely unchanged, except the transient expression of Gγ2 in a single basal layer of cells in the MOE during P7 and P14. Taken together, our comprehensive expression analyses reveal cell-type specific gene expression of multiple Gß and Gγ in sensory neurons of the olfactory system.