Usefulness of DIGE for the detection of protein profile in retained and released bovine placental tissues

A pilot study on the relationship between thrombospondin-1 (THBS1) and transforming growth factor beta1 (TGFβ1) in the bovine placenta during early mid-pregnancy as well as parturition with normally released and retained placenta

During pregnancy, it is necessary to create appropriate conditions for the development of the placenta and the fetus. However, during parturition, the placenta must be separated and subsequently removed as soon as possible to not expose the female to the possibility of infection. In this study, the relationship between thrombospondin-1 (THBS1) and transforming growth factor beta1 (TGFβ1) concentrations was described during bovine pregnancy (second, fourth, and sixth months; n = 3/each month), at normal parturition (NR) and parturition with fetal membrane retention (R). The presence of THBS1 and TGFβ1 was confirmed in bovine placental tissues of both maternal and fetal parts. Enzyme-linked immunosorbent assay showed statistically significant differences (p < 0.05) in THBS1 concentrations (pg/mg protein) between examined parturient samples (maternal part: 5.76 ± 1.61 in R vs. 2.26 ± 1.58 in NR; fetal part: 2.62 ± 1.94 in R vs. 1.70 ± 0.23 in NR). TGFβ1 concentrations (pg/mg protein) were significantly lower (p < 0.05) in the retained fetal membranes compared to the released fetal membranes in the maternal part of the placenta (26.22 ± 7.53 in NR vs. 17.80 ± 5.01 in R). The participation of THBS1 in the activation of TGFβ1 in parturient bovine placental tissues leading to the normal release of fetal membranes may be suggested.

Latest update on predictive indicators, risk factors, and 'Omic' technologies research of retained placenta in dairy cattle- review article

Retained placenta is a pathological condition defined as failure to expel fetal membranes within 12 -24h after parturition. It instigates important financial losses to the dairy industry causing considerable economic loss. It is a multifactorial disorder. Although different hypotheses have been proposed, contradictory results and no single factor explains the development of the disease. This indicates that there are overall significant gaps in our knowledge about the various factors affecting the etiopathology and pathobiology of the retained placenta. Thus, it will be of great interest to investigate the potential contributing factors that influence the occurrence of RP which provide us with the mechanisms to avoid the occurrence of the disease. In addition, different predictive indicators of RP should be part of our research, thus providing the essential procedures applied to deal with the disease and the development of novel therapeutic and prophylactic strategies in its management. Furthermore, lately, the molecular role takes attention to understanding its effect in the occurrence of the disease. Such information might help dairy scientists in the future to design better management and preventive practices for RP in dairy cows.

2D Electrophoretic pattern of bovine placental proteins during early-mid pregnancy

The Placenta, like every tissue, possesses its own characteristic protein profile, which may change within the course of pregnancy. These changes can be used for the elucidation of the mechanisms related to both physiology of pregnancy and pathological events. The aim of the study was to describe proteinergic profiles of maternal and fetal parts of bovine placenta during early-mid pregnancy by the use of 2D electrophoresis and MALDI TOF/TOF MS identification to evaluate dynamics of the possible changes necessary for placentation. Placental samples were collected from six pregnant cows (3-5 months) in the local abattoir. Placentomes were separated, and proteins were extracted and subjected to 2D electrophoresis and MALDI TOF/TOF identification. Out of 907 spots identified by the statistical analysis of gels, 54 were identified. Out of this number, 36 spots were significantly different between examined samples. Moreover, the obtained patterns differed between maternal and fetal parts of the placenta with regard to the intensity of staining, suggesting quantitative differences in protein content. These preliminary results are unique for this period of pregnancy. Such data are important for further experiments to obtain full protein profiles necessary to understand biochemical mechanisms underlying the attachment between fetal and maternal parts of the placenta during placentation. Moreover, the outcomes may help in elucidating pregnancy biomarkers in the future.

The preliminary studies on protein profile in retained and not retained foetal membranes in heavy draft mares

Protein profile of the placenta expresses its function and maintenance. Any alterations can be reflected in qualitative and quantitative changes in this profile. The aim of the present study was the evaluation of protein profile in the placenta of mares suffering from the retention of foetal membranes (FMR) by two separation methods and the comparison with physiologically released tissues. Placentas from 14 healthy, heavy draft mares were collected immediately after the expulsion of newborn. Tissues after homogenization and staining with fluorescent dyes were subjected to electrophoretic as well as chromatographic separation. Electrophoretic gels were statistically analysed for the presence and abundance of examined proteins, while some proteins were identified in chromatographic fractions. Out of 248 spots detected in endometrium, 38 differed significantly between FMR and control animals, while in allantochorion, respective values reached 241 and 27 spots (p < .05). Among identified proteins that expressed higher abundance in endometrium of FMR mares than control animals were prostaglandin reductase, dehydrogenase/reductase SDR family, and placental growth factor. These proteins are involved in regulation of parturition. Additionally, the following proteins responsible for physiological activity of a cell-guanine methyl transferase, aspartyl/asparaginyl beta-hydroxylase and GTP-binding protein, were identified. These proteins expressed higher abundance in allantochorion of FMR mares than in controls. This preliminary study confirmed the disturbances in protein pattern between foetal membranes in FMR and healthy mares. Further qualitative and quantitative experiments are necessary to deepen our knowledge on the mechanisms of the retention of foetal membranes in mares.

The comparison of protein map between retained and released bovine placenta

Placental retention in cows may be the result of altered protein pattern in comparison to physiologically released fetal membranes. Aim of study was to separate and identify proteins from maternal and fetal part of placenta and to compare them between released and retained fetal membranes. Six not retained and 6 retained tissues were obtained from healthy cows during routinely performed caesarian section. Cows were allocated to appropriate groups retrospectively. Samples were homogenized in phosphate buffer and subjected to 2D electrophoresis. After analysis of gels selected spots were excised and proteins were identified by MS. Two-dimensional electrophoresis detected and identified 886 spots in examined tissues. Significant differences (p < .05) were noticed between appropriate parts of retained and released placenta. In maternal part of retained placenta 40 spots showed lower abundance and 47 higher abundance in comparison to healthy samples. While in fetal part of retained placenta respective values were 60 and 125 proteins. Out of 73 identified proteins, 26 were significantly different between respective maternal (19) and fetal (7) part of retained and released placenta. In summary, protein profile of released and retained placenta express the presence and abundance of different proteins. It may suggest that selected proteins could be target molecules in searching for reasons for placental retention. Further identification of spots obtained here may provide with more detailed explanation of mechanisms of placental retention.

Is it useful to use several "omics" for obtaining valuable results?

The integration of cell communication and the transfer of signals from stimuli via transcription to translation and further to activation of new protein is crucial for appropriate metabolism and function of living organisms. The overall elucidation and the examination of these complex processes require multistep laboratory approaches in order to obtain results which will not only detect particular stage but also indicate the mechanisms lying upon this process. Such results will be reliable because they will cover multidirectional methods and approaches. The analysis of currently available results already provided with the conclusion that often single omics approach does not correspond with other expected information and may bring misinterpretations. That is why the integration of several "omics" is useful for searching entire explanations and answers as well as appropriate interpretation of obtained complex results. The hypothesis was stated that "from transcriptomics can not be concluded to proteomics". This review focuses on the reasons for the integration of transcriptomic, proteomic and other-omics analysis. Moreover it also describes the examples of clinical meanings and mentions some methods used in these approaches.

Proteomics and metabolomics characterizing the pathophysiology of adaptive reactions to the metabolic challenges during the transition from late pregnancy to early lactation in dairy cows

The transition from late pregnancy to early lactation is a critical period in a dairy cow's life due to the rapidly increasing drain of nutrients from the maternal organism towards the foetus and into colostrum and milk. In order to cope with the challenges of parturition and lactation, comprehensive adaptive reactions comprising the endocrine and the immune system need to be accomplished. There is high variation in this coping ability and both metabolic and infectious diseases, summarized as "production diseases", such as hypocalcaemia (milk fever), fatty liver syndrome, laminitis and ketosis, may occur and impact welfare, productive lifespan and economic outcomes. Proteomics and metabolomics have emerged as valuable techniques to characterize proteins and metabolite assets from tissue and biological fluids, such as milk, blood and urine. In this review we provide an overview on metabolic status and physiological changes during the transition period and the related production diseases in dairy cows, and summarize the state of art on proteomics and metabolomics of biological fluids and tissues involved in metabolic stress during the peripartum period. We also provide a current and prospective view of the application of the recent achievements generated by omics for biomarker discovery and their potential in diagnosis.

BIOLOGICAL SIGNIFICANCE

For high-yielding dairy cows there are several "occupational diseases" that occur mainly during the metabolic challenges related to the transition from pregnancy to lactation. Such diseases and their sequelae form a major concern for dairy production, and often lead to early culling of animals. Beside the economical perspective, metabolic stress may severely influence animal welfare. There is a multitude of studies about the metabolic backgrounds of such so called production diseases like ketosis, fatty liver, or hypocalcaemia, although the investigations aiming to assess the complexity of the pathophysiological reactions are largely focused on gene expression, i.e. transcriptomics. For extending the knowledge towards the proteome and the metabolome, the respective technologies are of increasing importance and can provide an overall view of how dairy cows react to metabolic stress, which is needed for an in-depth understanding of the molecular mechanisms of the related diseases. We herein review the current findings from studies applying proteomics and metabolomics to transition-related diseases, including fatty liver, ketosis, endometritis, hypocalcaemia and laminitis. For each disease, a brief overview of the up to date knowledge about its pathogenesis is provided, followed by an insight into the most recent achievements on the proteome and metabolome of tissues and biological fluids, such as blood serum and urine, highlighting potential biomarkers. We believe that this review would help readers to be become more familiar with the recent progresses of molecular background of transition-related diseases thus encouraging research in this field.

Preliminary data on possible protein markers of parturition in cows

Parturition is one of the most important events in reproduction. Regardless of many studies, exact time for pregnancy termination and onset of parturition is impossible to determine. The aim of this study was to describe and to compare protein profile of plasma from healthy pregnant cows (n = 6) at following five time points: 2 weeks, 1 week before, at parturition, 1 week and 2 weeks after parturition to search for possible protein markers of parturition. Plasma samples were analysed by 1D and 2D electrophoresis, and selected spots were identified by mass spectrometry. Protein profile showed no uniform pattern. Seventy spots differed at least for one sampling point from the time point 2 weeks before parturition which served as reference. Thirty spots expressed higher intensity of staining 1 week as 2 weeks before parturition while 13 showed opposite relationship. Twenty two spots expressed higher intensity of staining at parturition as 2 weeks before delivery while 15 showed opposite relationship. Eighteen spots expressed higher intensity of staining 2 weeks before parturition as 1 week post-partum while 2 showed opposite relationship. Fifteen spots expressed higher intensity of staining 2 weeks before parturition as 2 weeks after delivery while 14 showed opposite relationship. Thirty-five proteins, belonging to different functional groups, were identified. Of them, 15 spots differed significantly between parturition and 2 weeks before delivery. Among them were metalloproteinase inhibitor and LDH which seem to be the most promising molecules considered as parturition markers due to their functions.

Challenges and opportunities of bovine milk analysis by mass spectrometry

Bovine milk and its products (e.g. cheese, yoghurt) are an important part of human diet with beneficial effects for all ages. Although analyses of different milk components (e.g. proteins, lipids) pose huge challenges, the use of mass spectrometric (MS)-based techniques is steadily improving our understanding of the complexity of the biological traits that effect milk yield and its components to meet the global demand arising from population growth. In addition, different milk constituents have various applications in veterinary research and medicine, including early disease diagnosis. The aim of the review is to present an overview of the progress made in MS-based analysis of milk, and suggest a multi-pronged MS strategy to better explore different milk components for translational and clinical utilities.

Cellular and molecular mechanisms involved in placental separation in the bovine: A review

Retention of fetal membranes (RFM), where the fetal placenta is not expelled within 8-12 hr after calving, lowers bovine productivity and fertility, resulting in significant economic loss to the dairy industry. Several risk factors that predispose an individual to RFM are known, but a unifying pathogenesis remains elusive due to its multifactorial etiology. Fetal membrane separation and expulsion after parturition involves structural and immunological changes of the bovine placentome that are governed predominantly by steroid hormones and the prostaglandin milieu of late pregnancy and parturition. Maturation of the placentome, a gradual and concerted event of late gestation, is likely initiated by the up-regulation of fetal major histocompatibility complex class I in the interplacentomal region-which increases the apoptosis of binucleate and other trophoblastic cells, the degradation of collagen in the extracellular matrix by matrix metalloproteinases, and an influx of phagocytic leukocytes. Shear force further distorts the crypt architecture of the mature placentomes when they are forced against the fetus during the second stage of labor. Cotyledon dehiscence from the caruncular crypts is completed following fetal expulsion as a result of acute shrinkage of the cotelydonary villi as well as reduced perfusion to the caruncle; the secundinae is expelled by uterine contractions. A better understanding of placentomal maturation, intra-partum, and immediate postpartum changes of the placentome should help develop strategies for the treatment and prevention of RFM. The present review proposes a model of placentome maturation and separation of fetal membranes in the dairy cow.