Primary structures of different isoforms of buffalo pregnancy-associated glycoproteins (BuPAGs) during early pregnancy and elucidation of the 3-dimensional structure of the most abundant isoform BuPAG 7.

Pregnancy-associated glycoproteins (PAGs) are expressed during pregnancy by the trophoectodermal cells of fetus. Presence of PAGs in dam's circulation has been widely used in pregnancy diagnosis. The present study reports the identification and characterization of different PAG isoforms in buffalo during early stages of pregnancy. The PAG mRNAs isolated from fetal cotyledons (Pregnancy stages: 45, 75 and 90 days) were successfully cloned in pJET1.2 vector and transformed in E. coli. A total of 360 random clones were sequenced and correlated with their stages of expression. A total of 12 isoforms namely, BuPAG 1, 2, 4, 6, 7, 8, 9, 13, 15, 16, 18 and one new isoform were identified. BuPAG 7 was found as the most abundant isoform in all three stages followed by BuPAG 18. Further, a large number of variants were found for most of these isoforms. Phylogenetic relationship of identified BuPAGs showed that BuPAG 2 belonged to an ancient group while other members clustered with modern group. Three-dimensional (3D) structure of BuPAG 7 was determined by homology modeling and molecular dynamic (MD) simulations which displayed a typical fold represented by other aspartic proteinase (AP) family members. Molecular docking of Pepstatin inhibitor with BuPAG 7 revealed to interact through various hydrogen bonding and hydrophobic interactions. Various amino acid substitutions were observed in peptide-binding cleft of BuPAG 7. Superimposition of BuPAG 7 with homologous structures revealed the presence of a 35-41 amino acid long insertion (alpha helix connected by two loops) near the N- terminus which seems to be a unique feature of BuPAG 7 in AP family. This is the first report on identification and sequence characterization of PAG isoforms in buffalo with unique finding that these isoforms represent many transcript variants. We also report 3D structure of the most abundant isoform BuPAG 7 for the first time.

Effect of tropical thermal stress on peri-implantation immune responses in cows.

Pregnancy losses during the peri-implantation period cause a negative impact on the reproductive and economic performance of dairy herds. In this study, we investigated the possible immunological factors which may contribute to pregnancy loss during the peri-implantation period under different seasons of tropical conditions. Eighteen Karan Fries cows, six cows in each season (W: winter; HH: hot-humid; HD: hot-dry) were selected. These cows exhibited heat and were brought for artificial insemination (AI; day 0). Blood was collected on days 0, 10, 14, 16, 18, 21 and 28 post-AI. Pregnancy was confirmed by non-return to heat, progesterone assay and ultrasonography. Blood neutrophils were isolated and tested for their number, myeloperoxidase (MPO) concentrations and expression of cell adhesion molecules (CD11b, CD14, CD25, CD47), interferon tau stimulated genes (ISG15, MX1, OAS1) and chemokine receptors (CXCR1, CCL2). Plasma cortisol, progesterone, IL-2 and IL-10 were also estimated. Neutrophil number, MPO levels, the relative expression of various neutrophil receptors and plasma IL-2 were low between days 14-21 post-AI in all seasons. However, plasma cortisol and IL-10 were higher during the same period. The inflammatory activity of neutrophils, plasma IL-2 and cortisol were highest in HH, intermediate in HD and lowest in W season. However, plasma progesterone and IL-10 were highest in W season and lowest in HH season. Our results show that blood neutrophils sense the implanting embryo and downregulate their activity to ensure successful implantation; however, under harsh environmental conditions, it is a great challenge for the immune system to maintain such balance and thus it may negatively affect the outcome of pregnancy.

Genome-wide gene expression analysis of 45 days pregnant fetal cotyledons vis-a-vis non-pregnant caruncles in buffalo (Bubalus bubalis).

The crosstalk between fetus and mother starts with the onset of placental attachment to the uterus. The cotyledons and caruncles are the two anatomically distinct structures that play a crucial role in this physiological communication. Using Agilent Gene Chip Genome microarray, we measured the expression profile of pregnancy cotyledons in comparison to caruncular reminiscence of the uteri in non-pregnant buffalo (Bubalus bubalis) for the detection of the early post-pregnancy rapid changes in cellular expression of mRNA transcripts. We identified a total of 497 up- and 578 down-regulated genes with <0.05 the FDR corrected p-values using 4 replicates in each group (cotyledons and caruncles) and their role in pregnancy. Deep bioinformatics analysis of data revealed the cluster of genes involved at the placentome level for various functions such as fetus attachment, transport of nutrition, and immune response. Importantly, the pathways like Hedgehog/Calcium/Wnt signalling, cell cycle regulation and immune responses regulatory functions were highly enriched by the differentially identified genes. A very highly up-regulated IL-2 specific gene showed the role of interleukin-2 signalling in the attachment of the embryo. It was observed that the genes responsible for immune response were downregulated, suggesting an immune suppressive environment which is required to adopt the semiallogeneic fetus for a successful pregnancy. To further evaluate and validate the data, we have performed qRT-PCR analysis of twenty-one genes. The present study highlights the repertoire of active transcripts in the junction of cotyledons and caruncles, which are essential for a successful onset and completion of pregnancy.

Identification of potential protein biomarkers for early detection of pregnancy in cow urine using 2D DIGE and label free quantitation.

BACKGROUND: An early, reliable and noninvasive method of early pregnancy diagnosis is prerequisite for efficient reproductive management in dairy industry. The early detection of pregnancy also help in to reduce the calving interval and rebreeding time which is beneficial for industries as well as farmers. The aim of this work is to identify potential biomarker for pregnancy detection at earlier stages (16-25 days). To achieve this goal we performed DIGE and LFQ for identification of protein which has significant differential expression during pregnancy. RESULTS: DIGE experiment revealed a total of eleven differentially expressed proteins out of which nine were up regulated having fold change ≥1.5 in all time points. The LFQ data analysis revealed 195 differentially expressed proteins (DEPs) out of 28 proteins were up-regulated and 40 down regulated having significant fold change ≥1.5 and ≤0.6 respectively. Bioinformatics analysis of DEPs showed that a majority of proteins were involved in regulation of leukocyte immunity, endopeptidase inhibitor activity, regulation of peptidase activity and polysaccharide binding. CONCLUSION: This is first report on differentially expressed protein during various time points of pregnancy in cow to our best knowledge. In our work, we identified few proteins such MBP, SERPIN, IGF which were differentially expressed and actively involved in various activities related to pregnancy such as embryo implantation, establishment and maintenance of pregnancy. Due to their involvement in these events, these can be considered as biomarker for pregnancy but further validation of is required.

Functional characterization of Mammary Gland Protein-40, a chitinase-like glycoprotein expressed during mammary gland apoptosis.

MGP-40 is a chitinase-like protein which is over expressed during mammary gland involution. However, its physiological function in the mammary gland is poorly understood. In the present investigation, we have reported the functional significance of buffalo specific MGP-40 in the mammary gland by using an in vitro model of the buffalo mammary epithelial cell (BuMEC) line. MGP-40 was highly up regulated in BuMECs in serum starved condition as well as after treatment with prolactin suggesting its role in the stress response. Subsequently, to study the effect of MGP-40 on BuMECs, the cells were transfected with a mammalian expression construct of pCI neo harboring MGP-40 gene. It was observed that over expression of MGP-40 enhanced proliferation of BuMECs and protected the cells from apoptosis under serum free condition. In contrast, MGP-40 attenuated the mitogenic effect of insulin in BuMECs. Besides, over expression of the MGP-40 reduced dome formation, acinar polarization and casein synthesis in BuMECs in the presence of lactogenic hormones, it also induced Stat3 phosphorylation and epithelial to mesenchymal transition (EMT) -like features. Together, our data suggest that MGP-40 is involved in protection of BuMECs under stress conditions, inhibits cellular differentiation and induces EMT-like features. A schematic diagram depicting possible association of MGP-40 in various molecular pathways has been presented.

Profiling of urinary proteins in Karan Fries cows reveals more than 1550 proteins.

Urine is a non-invasive source of biological fluid, which reflects the physiological status of the mammals. We have profiled the cow urinary proteome and analyzed its functional significance. The urine collected from three healthy cows was concentrated by diafiltration (DF) followed by protein extraction using three methods, namely methanol, acetone, and ammonium sulphate (AS) precipitation and Proteo Spin urine concentration kit (PS). The quality of the protein was assessed by two-dimensional gel electrophoresis (2DE). In-gel digestion method revealed more proteins (1191) in comparison to in-solution digestion method (541). Collectively, 938, 606 and 444 proteins were identified in LC-MS/MS after in-gel and in-solution tryptic digestion of proteins prepared by AS, PS and DF methods, respectively resulting in identification of a total of 1564 proteins. Gene ontology (GO) using Panther7.0 grouped the majority of the proteins into cytoplasmic (location), catalytic activity (function), and metabolism (biological processes), while Cytoscape grouped proteins into complement and coagulation cascades; protease inhibitor activity and wound healing. Functional significance of few selected proteins seems to play important role in their physiology. Comparative analysis with human urine revealed 315 overlapping proteins. This study reports for the first time evidence of more than 1550 proteins in urine of healthy cow donors. This article is part of a Special Issue entitled: Proteomics in India.