Identification of Differentially Expressed Gene Transcripts in Porcine Endometrium during Early Stages of Pregnancy

Unveiling genetic signatures associated with resilience to neonatal diarrhea in lambs through two GWAS approaches

Neonatal diarrhea presents a significant global challenge due to its multifactorial etiology, resulting in high morbidity and mortality rates, and substantial economic losses. While molecular-level studies on genetic resilience/susceptibility to neonatal diarrhea in farm animals are scarce, prior observations indicate promising research directions. Thus, the present study utilizes two genome-wide association approaches, pKWmEB and MLM, to explore potential links between genetic variations in innate immunity and neonatal diarrhea in Karacabey Merino lambs. Analyzing 707 lambs, including 180 cases and 527 controls, revealed an overall prevalence rate of 25.5%. The pKWmEB analysis identified 13 significant SNPs exceeding the threshold of ≥ LOD 3. Moreover, MLM detected one SNP (s61781.1) in the SLC22A8 gene (p-value, 1.85eE-7), which was co-detected by both methods. A McNemar's test was conducted as the final assessment to identify whether there are any major effective markers among the detected SNPs. Results indicate that four markers-oar3_OAR1_122352257, OAR17_77709936.1, oar3_OAR18_17278638, and s61781.1-have a substantial impact on neonatal diarrhea prevalence (odds ratio: 2.03 to 3.10; statistical power: 0.88 to 0.99). Therefore, we propose the annotated genes harboring three of the associated markers, TIAM1, YDJC, and SLC22A8, as candidate major genes for selective breeding against neonatal diarrhea.

Bifenox compromises porcine trophectoderm and luminal epithelial cells in early pregnancy by arresting cell cycle progression and impairing mitochondrial and calcium homeostasis

Bifenox is a widely used herbicide that contains a diphenyl ether group. However its global usage, the cell physiological effects that induce toxicity have not been elucidated. In this study, the effect of bifenox was examined in porcine trophectoderm and uterine epithelial cells to investigate the potential toxicity of the implantation process. To uncover the toxic effects of bifenox, cell viability and apoptosis following treatment with bifenox were evaluated. To investigate the underlying cellular mechanisms, mitochondrial and calcium homeostasis were investigated in both cell lines. In addition, the dysregulation of cell signal transduction and transcriptional alterations were also demonstrated. Bifenox reduced cell viability and significantly increased the number of cells arrested at the sub-G1 stage. Moreover, bifenox depolarized the mitochondrial membrane and upregulated the calcium flux into the mitochondria in both cell lines. Cytosolic calcium flux increased in porcine trophectoderm (pTr) cells and decreased in porcine luminal epithelium (pLE) cells. In addition, bifenox activated the mitogen-activated protein kinase and phosphoinositide 3-kinase signaling pathways. Furthermore, bifenox inhibited the expression of retinoid receptor genes, such as RXRA, RXRB, and RXRG. Chemokine CCL8 was also downregulated at the mRNA level, whereas CCL5 expression remained unchanged. Overall, the results of this study suggest that bifenox deteriorates cell viability by arresting cell cycle progression, damaging mitochondria, and controlling calcium levels in pTr and pLE cells. The present study indicates the toxic potential of bifenox in the trophectoderm and luminal epithelial cells, which can lead to implantation disorders in early pregnancy.

Picolinafen exposure induces ROS accumulation and calcium depletion, leading to apoptosis in porcine embryonic trophectoderm and uterine luminal epithelial cells during the peri-implantation period

The global use of herbicides accounts for more than 48% of total pesticide usage. Picolinafen is a pyridine carboxylic acid herbicide that is predominantly used to control broadleaf weeds in wheat, barley, corn, and soybeans. Despite its widespread use in agriculture, its toxicity in mammals has rarely been studied. In this study, we first identified the cytotoxic effects of picolinafen on porcine trophectoderm (pTr) and luminal epithelial (pLE) cells, which are involved in the implantation process during early pregnancy. Picolinafen treatment significantly decreased the viability of pTr and pLE cells. Our results demonstrate that picolinafen increased the number of sub-G1 phase cells and early/late apoptosis. In addition, picolinafen disrupted mitochondrial function and resulted in the accumulation of intracellular ROS, leading to a reduction in calcium levels in both the mitochondria and cytoplasm of pTr and pLE cells. Moreover, picolinafen was found to significantly inhibit the migration of pTr. These responses were accompanied by the activation of the MAPK and PI3K signal transduction pathways by picolinafen. Our data suggest that the deleterious effects of picolinafen on the viability and migration of pTr and pLE cells might impair their implantation potential.

Polymorphism of OPN and AREG Genes in Relation to Transcript Expression of a Panel of 12 Genes Controlling Reproduction Processes and Litter Size in Pigs

The aim of this study was to define the transcript expression of 12 genes, identify new polymorphisms in selected 2 genes and to estimate the association between the level of expression, gene polymorphism and litter size in sows. Two groups of sows were selected: 71 crossbred sows and 328 purebred sows. For transcript analysis endometrial tissue samples were collected, while blood was sampled for the purpose of DNA polymorphism analysis. For all animals data on litter size and weaned piglets were obtained. Transcript analysis of 12 genes was performed in the uterine endometrium of sows in the luteal and follicular phases. Eight out of 12 genes showed higher mRNA expression levels during the luteal phase (AREG, FABP3, IL1A, ITGAV, ITGB3, NMB, OPN, RBP4). In turn, higher expression levels in the follicular phase were observed for 4 genes (IL1B, PPARG, S100A8, SELL). Analysis of six new polymorphic sites within the OPN and AREG genes revealed the highest heterozygosity for OPNe6_Knoll, OPNp3_617 and AREGe2_317 polymorphisms and the lowest heterozygosity in the AREGe3_561 locus. Association analyses concerning transcript expression levels of the 12 genes and the OPN and AREG genotypes in the two groups of sows showed a significant relationship between the IL1A, ITGB3 transcript expression and the OPNe7_603 genotype also between OPNp3_617 genotype and ITGB3 transcript expression. With regard to the litter size and the number of weaned piglets a significant relation with the OPNp3_617, OPNe6_462 and AREGe2_317 genotypes was observed only in the purebred sows. Transcript expression of the genes encoding osteopontin and amphiregulin in the uterus of the sows affect reproductive traits by preparing the uterus for embryo reception.

Molecular Characterisation of Uterine Endometrial Proteins during Early Stages of Pregnancy in Pigs by MALDI TOF/TOF

The molecular mechanism underlying embryonic implantation is vital to understand the correct communications between endometrium and developing conceptus during early stages of pregnancy. This study’s objective was to determine molecular changes in the uterine endometrial proteome during the preimplantation and peri-implantation between 9 days (9D), 12 days (12D), and 16 days (16D) of pregnant Polish Large White (PLW) gilts. 2DE-MALDI-TOF/TOF and ClueGO^TM approaches were employed to analyse the biological networks and molecular changes in porcine endometrial proteome during maternal recognition of pregnancy. A total of sixteen differentially expressed proteins (DEPs) were identified using 2-DE gels and MALDI-TOF/TOF mass spectrometry. Comparison between 9D and 12D of pregnancy identified APOA1, CAPZB, LDHB, CCT5, ANXA4, CFB, TTR upregulated DEPs, and ANXA5, SMS downregulated DEPs. Comparison between 9D and 16D of pregnancy identified HP, APOA1, ACTB, CCT5, ANXA4, CFB upregulated DEPs and ANXA5, SMS, LDHB, ACTR3, HP, ENO3, OAT downregulated DEPs. However, a comparison between 12D and 16D of pregnancy identified HP, ACTB upregulated DEPs, and CRYM, ANXA4, ANXA5, CAPZB, LDHB, ACTR3, CCT5, ENO3, OAT, TTR down-regulated DEPs. Outcomes of this study revealed key proteins and their interactions with metabolic pathways involved in the recognition and establishment of early pregnancy in PLW gilts.

Integrating LCM-Based Spatio-Temporal Transcriptomics Uncovers Conceptus and Endometrial Luminal Epithelium Communication that Coordinates the Conceptus Attachment in Pigs

Attachment of conceptus to the endometrial luminal epithelium (LE) is a critical event for early placentation in Eutheria. Since the attachment occurs at a particular site within the uterus, a coordinated communication between three spatially distinct compartments (conceptus and endometrial LE from two anatomical regions of the uterus to which conceptus attaches and does not attach) is essential but remains to be fully characterized. Using the laser capture microdissection (LCM) technique, we firstly developed an approach that can allow us to pair the pig conceptus sample with its nearby endometrial epithelium sample without losing the native spatial information. Then, a comprehensive spatio-temporal transcriptomic profile without losing the original conceptus-endometrium coordinates was constructed. The analysis shows that an apparent difference in transcriptional responses to the conceptus exists between the endometrial LE from the two anatomically distinct regions in the uterus. In addition, we identified the communication pathways that link the conceptus and endometrial LE and found that these pathways have important roles in conceptus attachment. Furthermore, a number of genes whose expression is spatially restricted in the two different anatomical regions within the uterus were characterized for the first time and two of them (SULT2A1 and MEP1B) may cooperatively contribute to establish conceptus attachment in pigs. The results from our study have implications in understanding of conceptus/embryo attachment in pigs and other large polytocous species.