ABSTRACT
BACKGROUND: The degree of adipose tissue development at birth may influence neonatal survival and subsequent health outcomes. Despite their lower birth weights, piglets from Meishan sows (a fat breed with excellent maternal ability) have a higher survival rate than piglets from Large White sows (a lean breed). To identify the main pathways involved in subcutaneous adipose tissue maturation during the last month of gestation, we compared the proteome and the expression levels of some genes at d 90 and d 110 of gestation in purebred and crossbred Large White or Meishan fetuses gestated by sows of either breed. RESULTS: A total of 52 proteins in fetal subcutaneous adipose tissue were identified as differentially expressed over the course of gestation. Many proteins involved in energy metabolism were more abundant, whereas some proteins participating in cytoskeleton organization were reduced in abundance on d 110 compared with d 90. Irrespective of age, 24 proteins differed in abundance between fetal genotypes, and an interaction effect between fetal age and genotype was observed for 13 proteins. The abundance levels of proteins known to be responsive to nutrient levels such as aldolase and fatty acid binding proteins, as well as the expression levels of FASN, a key lipogenic enzyme, and MLXIPL, a pivotal transcriptional mediator of glucose-related stimulation of lipogenic genes, were elevated in the adipose tissue of pure and crossbred fetuses from Meishan sows. These data suggested that the adipose tissue of these fetuses had superior metabolic functionality, whatever their paternal genes. Conversely, proteins participating in redox homeostasis and apoptotic cell clearance had a lower abundance in Meishan than in Large White fetuses. Time-course differences in adipose tissue protein abundance were revealed between fetal genotypes for a few secreted proteins participating in responses to organic substances, such as alpha-2-HS-glycoprotein, transferrin and albumin. CONCLUSIONS: These results underline the importance of not only fetal age but also maternal intrauterine environment in the regulation of several proteins in subcutaneous adipose tissue. These proteins may be used to estimate the maturity grade of piglet neonates.
ABSTRACT
Among infertile couples, approximately half have to face with male infertility. In men with non-obstructive azoospermia, surgical retrieval testicular sperm extraction (TESE) of spermatozoa can be attempted, but with low success rates. A specific biomarker that could predict residual spermatogenesis would obviously be of interest before performing TESE. Thus, our aim was to identify biomarkers of residual spermatogenesis in seminal plasma of patients with non-obstructive azoospermia (NOA) using an isotope-coded protein label (ICPL)-based proteomic strategy coupled with conventional protein assay. This retrospective study was conducted in 40 men with NOA at the University Hospital of Nantes and Proteomics Core facility Biogenouest - Inserm U1085 - IRSET, Rennes, France. Comparative ICPL proteomic screening of frozen seminal plasma and correlation with TESE outcome allowed the identification of some differentially expressed proteins. Among them, lectin galactoside-binding, soluble 3 binding protein (LGALS3BP) expression was further confirmed using conventional protein assay, and its interest as a predictor of TESE outcome was then evaluated and compared with conventional clinical and hormonal markers of residual spermatogenesis. Among the 12 differentially expressed proteins identified with comparative ICPL proteomic strategy, seminal LGALS3BP expression was found to be significantly higher in men with successful TESE. Finally, comparative ICPL proteomic screening of seminal plasma appears to be a promising approach for the identification of biomarkers of residual spermatogenesis. LGALS3BP, associated with clinical and hormonal markers, could potentially be used as a predictive marker of successful TESE outcome in patients with NOA.
Subject(s)
Azoospermia/pathology , Proteomics , Spermatozoa/pathology , Testis/pathology , Adult , Humans , MaleABSTRACT
Stathmin is a protein known to be involved in various cell processes including cell proliferation and differentiation. It has already been described in the testis but its recent identification using a proteomic approach in mitotic spermatogenetic stem cells named spermatogonia (Guillaume et al., 2000) has lead us to reinvestigate its expression within the testis. Stathmin and its mRNAs were studied in isolated cells by Western and Northern blots and in situ using immunohistochemistry. We demonstrated that stathmin is indeed expressed in spermatogonia, and that it is also intensively expressed in the meiotic spermatocytes and in the first generations of spermatids. Furthermore, we showed aggregations of the protein in the cytoplasm of the later generations of spermatids preceding its elimination at the time of spermiation. Our Northern blots reveal the presence of two stathmin transcripts of 1.1 and 3.2 kb within the testis from the fetal stage onwards, in spermatogonia, spermatocytes, and spermatids. However, the 3.2 kb RNA transcript was barely detectable in the spermatids. Stathmin expression is known to be associated with microtubule dynamics. Therefore, its expression in the germ line is most probably related to the extremely complex structural cellular rearrangements occurring in germ cells during spermatogenesis. However, the exact role of stathmin and the reason of the existence of two transcripts in the male germ lineage awaits further investigation.
