Proteomic pattern of implantative human endometrial fluid in in vitro fertilization cycles.

PURPOSE: To assess whether there are proteins in endometrial fluid aspirate (EFA) that predict implantation. METHODS: The population under study consisted of 285 women undergoing embryo transfer (ET). Endometrial fluid aspiration was performed immediately before ET. Results of proteomic analysis of EFA were compared between 33 cases who achieved pregnancy and 33 who did not. Samples were analysed by 2D electrophoresis and mass spectrometry. Blood samples were studied by ELISA Pregnancy rates and maternal complications were compared to those in women refusing aspiration. RESULTS: We found 23 proteins differentially expressed in the EFA in conception cycles: 4 up-regulated proteins and 19 down-regulated (FC = 0.31 0.78) (among others, arginase-1, actin B, PARK-7, cofilin-1, stathmin, annexin-2 and CAPZB). Among the five studied proteins that were differentially expressed in EFA, none was differentially expressed in serum. The aspiration procedure had no impact on pregnancy rate. No maternal complications were reported. CONCLUSIONS: We found a very different protein profile in implantative cycles, the majority of proteins being down-regulated. This probably reflects a different endometrial functional status, more favourable to implantation. EFA proteomic analysis could be a useful tool in the planning ET strategies.

Quantum-dot-based suspension microarray for multiplex detection of lung cancer markers: preclinical validation and comparison with the Luminex xMAP® system.

A novel suspension multiplex immunoassay for the simultaneous specific detection of lung cancer markers in bronchoalveolar lavage fluid (BALF) clinical samples based on fluorescent microspheres having different size and spectrally encoded with quantum dots (QDEM) was developed. The designed suspension immunoassay was validated for the quantitative detection of three lung cancer markers in BALF samples from 42 lung cancer patients and 10 control subjects. Tumor markers were detected through simultaneous formation of specific immune complexes consisting of a capture molecule, the target antigen, and biotinylated recognition molecule on the surface of the different QDEM in a mixture. The immune complexes were visualized by fluorescently labeled streptavidin and simultaneously analyzed using a flow cytometer. Preclinical validation of the immunoassay was performed and results were compared with those obtained using an alternative 3-plex immunoassay based on Luminex xMAP® technology, developed on classical organic fluorophores. The comparison showed that the QDEM and xMAP® assays yielded almost identical results, with clear discrimination between control and clinical samples. Thus, developed QDEM technology can become a good alternative to xMAP® assays permitting analysis of multiple protein biomarkers using conventional flow cytometers.

Characterization of the human Nalpha-terminal acetyltransferase B enzymatic complex.

BACKGROUND: Human Nalpha-acetyltransferase complex B (hNatB) is integrated by hNaa20p (hNAT5/hNAT3) and hNaa25p (hMDM20) proteins. Previous data have shown that this enzymatic complex is implicated in cell cycle progression and carcinogenesis. In yeast this enzyme acetylates peptides composed by methionine and aspartic acid or glutamic acid in their first two positions respectively and it has been shown the same specificity in human cells. METHODS: We have silenced hNAA20 expression in hepatic cell lines using recombinant adenoviruses that express specific siRNAs against this gene and analyzed cell cycle progression and apoptosis induction after this treatment. Immunopurified hNatB enzymatic complexes from human cell lines were used for analyzing hNatB in vitro enzymatic activity using as substrate peptides predicted to be acetylated by NatB. RESULTS: hNAA20 silencing in hepatic cell lines reduces cell proliferation in a p53 dependent and independent manner. At the same time this treatment sensitizes the cells to a proapototic stimulus. We have observed that the hNatB complex isolated from human cell lines can acetylate in vitro peptides that present an aspartic or glutamic acid in their second position as has been described in yeast. CONCLUSION: hNatB enzymatic complex is implicated in cell cycle progression but it exerts its effects through different mechanisms depending on the cellular characteristics. This is achievable because it can acetylate a great number of peptides composed by an aspartic or glutamic acid at their second residue and therefore it can regulate the activity of a great number of proteins.

Comprehensive proteomic analysis of human endometrial fluid aspirate.

The endometrial fluid is a noninvasive sample which contains numerous secreted proteins representative of endometrial function and reflects the state of the endometrium. In this study, we describe, for the first time, a comprehensive catalogue of proteins of the endometrial fluid during the secretory phase of the menstrual cycle. To achieve this objective, three different but complementary strategies were used: First, in-solution digestion followed by reverse phase high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS); second, protein separation by denaturing one-dimensional electrophoresis (SDS-PAGE) followed by HPLC-MS/MS analysis. Finally, two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) followed by MALDI-TOF/TOF analysis. The combination of the three strategies led to the successful identification of 803 different proteins in the International Protein Index (IPI) human database (v3.48). An extensive description of the endometrial fluid proteome will help provide the basis for a better understanding of a number of diseases and processes, including endometriosis, endometrial cancer and embryo implantation. We believe that the thorough catalogue of proteins presented here can serve as a valuable reference for the study of embryo implantation and for future biomarker discovery involved in pathologic alterations of endometrial function.

Gef1p, a new guanine nucleotide exchange factor for Cdc42p, regulates polarity in Schizosaccharomyces pombe.

Schizosaccharomyces pombe cdc42(+) regulates cell morphology and polarization of the actin cytoskeleton. Scd1p/Ral1p is the only described guanine nucleotide exchange factor (GEF) for Cdc42p in S. pombe. We have identified a new GEF, named Gef1p, specifically regulating Cdc42p. Gef1p binds to inactive Cdc42p but not to other Rho GTPases in two-hybrid assays. Overexpression of gef1(+) increases specifically the GTP-bound Cdc42p, and Gef1p is capable of stimulating guanine nucleotide exchange of Cdc42p in vitro. Overexpression of gef1(+) causes changes in cell morphology similar to those caused by overexpression of the constitutively active cdc42G12V allele. Gef1p localizes to the septum. gef1(+) deletion is viable but causes a mild cell elongation and defects in bipolar growth and septum formation, suggesting a role for Gef1p in the control of cell polarity and cytokinesis. The double mutant gef1delta scd1delta is not viable, indicating that they share an essential function as Cdc42p activators. However, both deletion and overexpression of either gef1(+) or scd1(+) causes different morphological phenotypes, which suggest different functions. Genetic evidence revealed a link between Gef1p and the signaling pathway of Shk1/Orb2p and Orb6p. In contrast, no genetic interaction between Gef1p and Shk2p-Mkh1p pathway was observed.