Association between human oocyte developmental competence and expression levels of some cumulus genes.

At present, oocyte selection is mainly based upon morphological criteria but it is generally acknowledged that its reliability requires further improvement. The aim of this study was to determine whether transcript levels in cumulus cells can provide a useful marker of oocyte developmental competence in vitro. A retrospective study was performed on cumulus cells isolated from 90 oocytes retrieved from 45 patients. Upon fertilization, 35 oocytes originated good-quality embryos and 36 developed into poor-quality embryos, whereas 19 failed to be fertilized. Semi-quantitative measurement of hyaluronic acid synthase 2 (HAS2), gremlin1 (GREM1), and pentraxin 3 (PTX3) mRNAs was performed and data for all genes were obtained from all the samples. Cumulus cells isolated from oocytes that originated high-quality embryos on day 3 of culture had HAS2 and GREM1 transcript levels higher than those detected in cells from oocytes that did not fertilize or developed into poor-quality embryos. No differences were observed in PTX3 levels. Results indicate that the measurement of HAS2 and GREM1 levels in cumulus cells would reliably complement the morphological evaluation providing a useful tool for selecting oocytes with greater chances to be fertilized and develop in vitro.

Aroclor-1254 affects mRNA polyadenylation, translational activation, cell morphology, and DNA integrity of rat primary prostate cells.

Environmental xenobiotics have been shown to act as endocrine disruptors and to be implicated in increased cancer susceptibility. In particular, there is a significant concern regarding the impact of these contaminants on prostate cancer development and progression. However, the mechanisms with which these contaminants exert their detrimental effects are yet unclear and need to be further elucidated. In the present study, we investigated the effects of Aroclor-1254, a mixture of more than 60 environmental pollutants belonging to the polychlorinated biphenyl family, on rat prostate primary cultures. The results obtained after 24-h exposure indicated the ability of this contaminant mixture to influence mRNA stability and length of the 3'-end poly(A)tail of Connexin-32, Connexin-43, and heat shock protein-70. Consistent with this observation, immunostaining experiments demonstrated the altered availability of the encoded proteins. We also focused our attention on possible effects of Aroclor-1254 on cell morphology and could detect ultrastructural changes with gap junction disruption, fusion of single cells into clusters, and different aspects of apoptosis that became evident when exposure to Aroclor-1254 was extended to 72 h. The effects on the nuclear compartment were confirmed by the results obtained with Comet assay that showed DNA decompression and double-strand breaks already after 24-h exposure. Taken together, these findings show a detrimental effect of Aroclor 1254 on rat prostate cells and indicate a possible association between exposure to polychlorinated biphenyl mixture and induction of transformation process in prostate cells.

Temporal and spatial control of gene expression in early embryos of farm animals.

A gradual transition from oocyte-derived mRNA and proteins to full embryonic transcription characterises early embryonic development. Messenger RNAs and proteins of maternal origin are accumulated into the oocyte throughout its growth inthe ovary. Upon fertilisation, sev eral mechanisms ar e activated that controlthe appropriate use of such material and prepare for the synthesis of new products. The present review will describe some of the mechanisms active in early embryos of domestic species. Data will be presented on the control of gene expression by the 3' untranslated regions and their interaction with specialised sequences at the 5' cap end. The process of RNA sorting and localisation, initially described in different cell types and in oocytes of lower species, will also be discussed, particularly in relation to its possible role in regulating early pig development. Finally, specific genes involved in the activation of cattle embryonic transcription will be described. This brief overview will provide some suggestions on how these different mechanisms may be integrated and cooperate to ensure the correct initiation of embryonic development.

Effects of endocrine disruptors on developmental and reproductive functions.

Endocrine disruptors (EDs) are exogenous environmental molecules that may affect the synthesis, secretion, transport, metabolism, binding, action, and catabolism of natural hormones in the body. EDs may thus interact with the endocrine system of animals and humans and can exert this effect even when present in minute amounts. EDs have adverse impacts on a number of developmental functions in wildlife and humans. Critical periods of urogenital tract and nervous system development in-utero and during early post-natal life are especially sensitive to hormonal disruption. Furthermore a wide range of hormone-dependent organs (pituitary gland, hypothalamus, reproductive tract) are targets of EDs disrupting effects in adult subjects, possibly resulting in cell transformation and cancer. At present about 60 chemicals have been identified and characterized as EDs and belong to three main groups: (a) synthetic compounds utilized in industry, agriculture and consumer products; (b) synthetic molecules used as pharmaceutical drugs and (c) natural chemicals found in human and animal food (phytoestrogens). In the present review we will give special attention to the family of Polychlorinated biphenyls (also indicated as PCBs) because of their persistence in the environment, ability to concentrate up the food chain, continued detection in environmental matrices, and ability to be stored in the adipose tissue of animals as well as humans. The detrimental effects of these compounds, and of EDs more in general, on health and reproduction will be discussed, presenting experimental data aimed at understanding the molecular mechanisms involved in their action.