Type I interferon receptors and interferon-τ-stimulated genes in peripheral blood mononuclear cells and polymorphonuclear leucocytes during early pregnancy in beef heifers

Influence of sub-clinical endometritis on early pregnancy predictors and proinflammatory cytokines in circulating immune cells in dairy cows

In Experiment 1, PBMC were isolated from cows considered healthy or with SCE (n=6/group) on Days 0 (estrus) and 7 (diestrus) of a synchronized estrous cycle. In Experiment 2, on D21 (D0 was defined as the day of Fixed Timed Artificial Insemination (FTAI), cows were evaluated by ultrasonography to assess luteal blood perfusion and PBMC were isolated. On D32, cows were classified into: healthy pregnant (n=7), pregnant with SCE (n=4), healthy non-pregnant (n=8), and non-pregnant with SCE (n=10). Gene expression of ISGs (ISG15, OAS1, MX1 and IFI6) and proinflammatory cytokines (IL1-β, TNF-α and IFN-γ) were determined. Expression of ISG15, MX1, IFI6, TNF-α and IFN-γ did not differ between SCE and healthy cows and between Days 0 and 7. Expression of OAS1 and IL1-β were higher (P=0.02) on Day 7 than Day 0, regardlees of the SCE presence. In Exp.2, ISG15 abundance was 2.5-fold greater (P=0.0008), TNF-α was 2.2-fold greater (P=0.05), and IL1-β tended (P=0.06) to be 2.4-fold higher in pregnant than non-pregnant cows. Luteal blood perfusion was greater (P=0.01) in pregnant animals. In conclusion, OAS1 and IL1-β are transcripts upregulated in PBMC at diestrus, regardless of SCE occurrence. Proinflammatory cytokines are not affected by SCE occurrence, but IL1-β and TNF-α are upregulated in pregnant animals on D21 of pregnancy. ISG15 abundance is a good pregnancy predictor, regardless SCE presence.

Interferon-Tau in Maternal Peripheral Blood and Its Relationship with Progesterone and Pregnancy-Associated Glycoproteins in the Early Phases of Gestation in Water Buffalo

The aim of this study was to investigate the interferon tau (IFNt) concentration in the peripheral maternal blood during the early phase of pregnancy in buffalo cows and improve the knowledge on the physiological importance of circulating IFNt, evaluating the possible interaction with pregnancy-associated glycoproteins (PAGs) and progesterone (P4). Blood samples were taken from buffalo cows on day 0 (day of AI), 7, 14, 18, 28, and 40 post insemination for the IFNt, PAG, and P4 analysis and to determine the IFNt mRNA expression. The animals were categorized ex post into Pregnant, Non-pregnant and Embryo mortality groups. The interferon value was influenced by group (p = 0.003), being always higher in pregnant buffalo cows than in non-pregnant ones, while the embryo mortality group showed intermediate values between those for pregnant and non-pregnant animals. The mRNA expression of IFNt was not influenced by groups or any time points. The regression analysis that included IFNt as the independent variable showed that PAGs, from day 18 (p < 0.01), and P4, from day 28 (p < 0.05), were positively associated with IFNt values. The close associations among IFNt, PAGs and P4 demonstrate that all three molecules work together for fetal-placental well-being and pregnancy support. Unfortunately, the great individual variability in circulating IFNt makes this analysis unsuitable for early pregnancy diagnosis.

Viperin (RSAD2) gene expression in peripheral blood mononuclear cells of pregnant crossbred beef cows is altered by Bos indicus genetics

The expression of interferon (IFN) stimulated genes (ISGs) in lymphocytes has been used for pregnancy diagnosis in cattle. However, among-cow variability has yielded sub-optimal predictive accuracy. We hypothesized that the expression of ISGs (ISG15, OAS1, RSAD2, CLEC3B, and AKR1B1) in early pregnancy varies according to the proportion of Bos indicus (B. indicus) genetics on females. Multiparous cows were classified in three genetic groups, High Angus (HA; n = 45 [0-33% Brahman influence]), Angus-Brahman (AB; n = 30 [34-67%]), and High Brahman (HB; n = 19 [68-100%]) and submitted to a Select-Synch + CIDR protocol. Cows that displayed estrus (n = 94) were artificially inseminated (Day0; D0). On D19, blood samples were collected to obtain peripheral blood mononuclear cells (PBMC) and measure progesterone (P4) concentrations. On D30, pregnancy diagnosis was performed. The expression of RSAD2 in PBMC of pregnant cows was positively related to the proportion of B. indicus genetics of the groups, but not the expression of ISG15 and OAS1. In pregnant cows, the proportion of B. indicus genetics was negatively associated to circulating levels of P4 concentrations. The P4 concentrations were related positively with RSAD2 expression. ROC curve results determined that for cattle with B. indicus genetics lower than 67%, the CLEC3B and AKR1B1 combination was the most accurate option to predict the outcome of pregnancy. In cows with more than 68% of B. indicus genetics, RSAD2 provided the best accuracy. In conclusion, there is a relationship between the proportion of B. indicus genetics and the ISGs gene expression in PBMC during pregnancy.

Gene expression of pregnancy-associated glycoproteins-1 (PAG-1), interferon-tau (IFNt) and interferon stimulated genes (ISGs) as diagnostic and prognostic markers of maternal-fetal cellular interaction in buffalo cows

The aim of this study was to determine the presence of Pregnancy-associated glycoprotein -1 (PAG-1) mRNA expression in the maternal circulation of pregnant buffaloes during the early stage of pregnancy. Contemporaneously, the mRNA expression levels of Interferon-tau (IFNt) and some Interferon stimulated genes (ISGs) (interferon stimulated gene 15 ubiquitin-like modifier interferon, ISG15; Mixoviruses resistance 1 and 2, MX1 and MX2; 2',5'-oligoadenylate synthase 1,OAS1) were evaluated in order to expand our knowledge of the molecular processes involved in the early stages of pregnancy and to identify potential biomarkers of maternal-fetal cellular interaction in buffalo. The study was conducted on 38 synchronized and artificially inseminated buffalo cows (d 0), divided ex post into 3 groups: Pregnant (n = 17), Non-pregnant (n = 15) and Embryo mortality (n = 6). Blood samples were collected on d 14, 19, 28 and 40 after artificial insemination (AI) for peripheral blood mononuclear cells (PBMCs) isolation. Expression levels of mRNA of PAG-1, IFNt, ISG15. MX1, MX2 and OAS1 were measured using RT-qPCR. No significant changes were observed in IFNt and PAG gene expressions between groups, while significant differences (p < 0.001) were found for ISG15, MX1, MX2, and OAS1. Pairwise comparisons revealed that the differences between groups occurred on days 19 and 28 post-AI. ISG15 proved to have the best diagnostic performance for distinguishing between pregnant animals and animals that experienced embryo mortality with the ROC analysis. According to the results of the univariate analyses, day 19 was identified as the most indicative to discriminate between groups while the most reliable genes for this differentiation were ISG15, MX1 and MX2. MX2 proved to be the best gene for discriminating pregnant buffaloes using the discriminant analysis, while MX1 was the gene that best predicted embryo mortality. Our results showed that among PAG-1, IFNt and ISGs expression as diagnostic and prognostic markers of maternal-fetal cellular interaction in buffalo cows, ISGs proved to be the best peripheral biomarkers for predicting pregnancy and embryonic mortality during the peri-implantation period. These insights into the mechanisms behind maternal-fetal interaction and the development of a method for the early detection of embryo distress may enable us to implement effective strategies to support embryo survival.

Review: Endometrial function in pregnancy establishment in cattle

The endometrium is fundamentally required for successful pregnancy in ruminants and species where the posthatching conceptus undergoes a protracted elongation and peri-implantation phase of pregnancy. Moreover, there are substantial waves of pregnancy loss during this pre- and peri-implantation period of pregnancy the precise source of which has not been clearly defined i.e., the maternal uterine contribution to this loss. Understanding the molecular interactions required for successful pregnancy in cattle will allow us to intervene to support pregnancy success during this vulnerable window. The endometrium contributes to most key developmental milestones of pregnancy establishment, including (1) contributing to the regulation of the oestrus cycle, (2) nourishing the preimplantation conceptus, (3) responding to the conceptus to create a more receptive microenvironment, (4) providing essential biophysical support, and (5) signalling and producing factors which affect the mother systemically. This review will summarise what we currently know about conceptus-maternal interactions as well as identify the gaps in our knowledge that could be filled with newer in vitro model approaches. These include the use of microfluidics, organ-on-a-chip devices, and bioinformatic approaches. This will help maximise food production efficiency (both meat and dairy) and decrease the environmental burden, while enhancing our understanding of the fundamental processes required for successful implantation in cattle.

Decisive points for pregnancy losses in beef cattle

Beef cattle producers rely on each of their cows to produce a marketable calf each year to maintain a sustainable operation. Within the first month of gestation, pregnancy failures have been recorded to be upwards of 40-50%. From fertilisation to birth, there are numerous factors contributing to pregnancy failure. From the beginning of gestation oocyte competence is often a large factor impacting fertility as the dam contributes all mRNA for initial embryo development. Other factors contributing to early embryonic infertility include hormonal concentration and heat stress. After the embryo enters the uterus, it becomes critical for the uterus to be receptive to the developing conceptus. The embryo then begins to elongate and secrete interferon-tau to initiate maternal recognition of pregnancy; a requirement to establish and maintain bovine pregnancies. After a pregnancy completes these steps, placentation actively begins around day 22 of pregnancy and lasts until organogenesis. The fetal phase follows the embryonic phase where disease and/or toxins are often the cause of pregnancy failure at this period. However, fetal mortality has been reported to occur in less than 10% of pregnancies. Understanding of the many factors influencing infertility needs to be further investigated to increase pregnancy success in beef cattle.

Interferon Tau (IFNt) and Interferon-Stimulated Genes (ISGs) Expression in Peripheral Blood Leukocytes and Correlation with Circulating Pregnancy-Associated Glycoproteins (PAGs) during Peri-Implantation and Early Pregnancy in Buffalo Cows

The objective of this study was to analyze interferon-stimulated genes (ISGs) and interferon tau (IFNt) gene expression in peripheral blood leukocytes during the peri-implantation period and until 40 days of pregnancy in buffalo cows. Relationships were also examined between the expression of ISGs and IFNt and pregnancy-associated glycoproteins (PAGs) peripheral plasma concentration. Buffalo cows were synchronized and artificially inseminated (d 0). Blood samples were collected on days 0, 18, 28 and 40 after artificial insemination (AI) for peripheral blood mononuclear cells (PBMCs) and polymorphonuclear leukocytes (PMNs) isolation and PAGs radioimmunoassay analysis. The study was carried out on 21 buffalo cows divided ex post into Pregnant (n = 12) and Non-pregnant (n = 9) groups. Steady state levels of OAS1, MX2, ISG15 and IFNt mRNA were measured by RT-qPCR and their estimated marginal means (p < 0.01 for all) were higher in pregnant than non-pregnant buffaloes, both in PBMCs and PMNs. In PBMCs, pairwise comparisons showed that OAS1 and MX2 expressions differed between pregnant and non-pregnant buffaloes on all the days of observation (p < 0.001), while significant differences in ISG15 and IFNt started from day 28 post-AI (p < 0.05). In PMNs, ISG15 expression differed between groups only at days 18 and 28 (p < 0.001), while comparisons were always significant for IFNt (p < 0.05). The expression of all genes, except ISG15 as determined in PMNs, was positively associated with PAGs plasma concentrations (p < 0.05). This work showed a significant increase in ISGs and IFNt expressions in PBMCs and PMNs in buffalo during the peri-implantation period and early pregnancy, and their correlation with PAGs plasma concentration.

MX2: Identification and systematic mechanistic analysis of a novel immune-related biomarker for systemic lupus erythematosus

Background

Systemic lupus erythematosus (SLE) is an autoimmune disease that involves multiple organs. However, the current SLE-related biomarkers still lack sufficient sensitivity, specificity and predictive power for clinical application. Thus, it is significant to explore new immune-related biomarkers for SLE diagnosis and development.

Methods

We obtained seven SLE gene expression profile microarrays (GSE121239/11907/81622/65391/100163/45291/49454) from the GEO database. First, differentially expressed genes (DEGs) were screened using GEO2R, and SLE biomarkers were screened by performing WGCNA, Random Forest, SVM-REF, correlation with SLEDAI and differential gene analysis. Receiver operating characteristic curves (ROCs) and AUC values were used to determine the clinical value. The expression level of the biomarker was verified by RT‒qPCR. Subsequently, functional enrichment analysis was utilized to identify biomarker-associated pathways. ssGSEA, CIBERSORT, xCell and ImmuCellAI algorithms were applied to calculate the sample immune cell infiltration abundance. Single-cell data were analyzed for gene expression specificity in immune cells. Finally, the transcriptional regulatory network of the biomarker was constructed, and the corresponding therapeutic drugs were predicted.

Results

Multiple algorithms were screened together for a unique marker gene, MX2, and expression analysis of multiple datasets revealed that MX2 was highly expressed in SLE compared to the normal group (all P < 0.05), with the same trend validated by RT‒qPCR (P = 0.026). Functional enrichment analysis identified the main pathway of MX2 promotion in SLE as the NOD-like receptor signaling pathway (NES=2.492, P < 0.001, etc.). Immuno-infiltration analysis showed that MX2 was closely associated with neutrophils, and single-cell and transcriptomic data revealed that MX2 was specifically expressed in neutrophils. The NOD-like receptor signaling pathway was also remarkably correlated with neutrophils (r >0.3, P < 0.001, etc.). Most of the MX2-related interacting proteins were associated with SLE, and potential transcription factors of MX2 and its related genes were also significantly associated with the immune response.

Conclusion

Our study found that MX2 can serve as an immune-related biomarker for predicting the diagnosis and disease activity of SLE. It activates the NOD-like receptor signaling pathway and promotes neutrophil infiltration to aggravate SLE.

Specific activation of embryonic IFNAR1 and endometrial IFNAR2 induced by embryonic IFNτ directs normal uterine fate for bovine early implantation

Interferon-tau (IFNτ), as an antiluteolytic factor secreted by trophoderm during the pregnancy of ruminants, actually functions by activating the IFNτ receptor 1 (IFNAR1) and IFNτ receptor 2 (IFNAR2). However, it has not been clearly understood how IFNτ-IFNAR cascade regulation processes between the embryo and uterine epithelial cells in ruminants. In this study, we found the expression and location of IFNτ in the bovine blastocysts from different production sources. IFNτ, IFNAR1 and IFNAR2 were all located in the trophoblast cells of the blastocyst. However, the fluorescence intensity of IFNAR1 was consistent with that of IFNτ. Antagonizing the expressions of IFNAR1 and IFNAR2 in embryos and co-culture with endometrial epithelium cells (EECs) reduced the expressions of Integrin αv β3, WNT7A, and ISG15 in EECs. Knocking out IFNAR1 and IFNAR2 reduce the expressions of Integrin αv β3 and WNT7A in EECs, the deletion of IFNAR2 gene has a greater impact than that of IFNAR1 gene. IFNAR1^-/IFNAR2⁺ and IFNAR1⁺/IFNAR2^- EECs were co-cultured with IVF embryos, the expression of Integrin αv β3 was inhibited, and the inhibition of IFNAR1⁺/IFNAR2^- was much stronger, and the expression of WNT7A was not inhibited. The expressions of Integrin αv β3 and WNT7A did not change significantly after IFNAR1^-/IFNAR2⁺ and IFNAR1⁺/IFNAR2^- co-culture with PA embryos. All of these results strongly suggest that specific activation of embryonic IFNAR1 and endometrial IFNAR2 induced by embryonic IFNτ directs normal uterine preparation for bovine early implantation.

Detection of nonpregnant cows and potential embryo losses by color Doppler ultrasound and interferon-stimulated gene expression in grazing dairy cows

Many studies have been conducted to estimate pregnancy losses between 19 and 34 d after artificial insemination (AI) in dairy cows managed under confinement-based systems, but few studies have examined embryo mortality during this interval in dairy cows managed under gazing systems. The objectives of this prospective cohort study were (1) to assess the diagnostic value of the corpus luteum (CL) blood perfusion (BP) evaluation by Doppler ultrasound (US) to detect nonpregnant cows at 19 to 20 d post-AI, and (2) to assess the rate of potential embryo mortality between 19 to 34 d post-AI. The CL-BP of all cows included in the study (n = 131) was examined on farm by power and color mode of Doppler US and later using an image processing software by a second evaluator. The endometrium thickness and echotexture were evaluated by B-mode US at the same visit to assess if the nonpregnancy diagnosis could be improved at 19 to 20 d post-AI by this additional diagnostic tool. Blood samples were obtained at 19 to 20 d post-AI for progesterone (P4) measurement by chemiluminescence and to determine the mRNA expression of ISG by real-time PCR. Pregnancy diagnosis based on embryo visualization was performed at 33 to 34 d post-AI by US B-mode. In parallel interpretation, ISG15 and MX2 mRNA expression in leukocytes [sensitivity (Se), 100%] were regarded as suitable biomarkers for early pregnancy and were selected for molecular characterization of pregnancy at 19 to 20 d post-AI. At 19 to 20 d post-AI, 61.1% of the cows had positive CL-BP by Doppler US (Se, 98.0%), 62.7% had ISG mRNA expression in leukocytes over the cutoff point (Se, 95.7%), and 50.8% were positive, based on the combination of ISG mRNA expression, CL-BP by Doppler US, and P4 concentration (Se, 100%), and were considered as possible pregnant. At 33 to 34 d, the pregnancy rate was 37.4% diagnosed by the B-mode US. Based on the expression of the selected biomarkers in cows with active CL, we found that 28.1% of the cows could have potentially lost their pregnancy between 19 and 34 d post-AI. The Doppler US color mode showed similar accuracy and a higher negative predictive value than the genes selected as biomarkers. The additional B-mode ultrasound evaluation of the uterine stratum vasculare and the endometrium thickness improved the diagnostic accuracy. Therefore, assessing the CL-BP by Doppler US allowed early detection of nonpregnant cows at 19 to 20 d post-AI. The combination of early CL-BP by Doppler US (d 19 to 20) with early embryo detection by B-mode US (d 33-34) could be used to facilitate earlier rebreeding of dairy cows.

Housing Conditions and a Challenge with Lipopolysaccharide on the Day of Estrus Can Influence Gene Expression of the Corpus Luteum in Gilts

The corpus luteum (CL) is a temporary endocrine gland that plays a decisive role in the reproductive physiology of gilts. Recently, it has been suggested that exogenous factors may compromise the normal functioning of the CL. In the present study, we aimed to understand to what extent an acute and systemic challenge with lipopolysaccharide (LPS) on the day of estrus could compromise gene expression of gilts’ CLs housed in different welfare conditions. For this, we housed 42 gilts in three different housing systems: crates, indoor group pens, and outdoor housing. Then, we challenged six females from each group with LPS and eight with saline (SAL) on the day of estrus. After slaughtering the gilts on the fifth day after the challenge, ovaries were collected for gene expression analysis by RT-qPCR. Housing system and LPS challenge did not have a significant interaction for any genes evaluated; thus, their effects were studied separately. We identified significant (p < 0.05) downregulation of the angiogenic genes VEGF and FTL1 among LPS-challenged animals. Meanwhile, we also observed upregulation of HSD3B1 gene among LPS-challenged animals. We found that STAR and LHCGR genes were differentially expressed depending on the housing system, which indicates that the environment may affect adaptation capabilities. Our results indicate that an acute health challenge on the estrus day alters CL gene expression; however, the role of the housing system remains uncertain.

Possible impact of neutrophils on immune responses during early pregnancy in ruminants

The interaction between early embryo and maternal immune system for the establishment of pregnancy is the focus of several studies; however, it remains unclear. The maternal immune response needs to keep a balance between avoiding any damage to the conceptus and maintaining its function in combating microbes as well. When conceptus-maternal crosstalk cannot achieve this balance, pregnancy losses might occur. Intercommunication between mother and conceptus is fundamental during early pregnancy to dictate the outcome of pregnancy. In ruminants, the embryo reacts with the maternal system mainly via interferon tau (IFNT) release. IFNT can act locally on the embryo and endometrial cells and systemically in several tissues and cells to regulate their response via the expression of interferon-stimulated genes (ISGs). Also, IFNT can induce the expression of inflammatory-related genes in immune cells. Day 7 embryo induces a shift in the maternal immune response towards anti-inflammatory (Th2) immune responses. During maternal recognition of pregnancy, peripheral mononuclear cells (PBMCs) and polymorphonuclear cells (PMNs) express markers that configure an anti-inflammatory response. However, PMNs response is more sensitive to the effects of IFNT. PMNs are more likely to express interferon-stimulated genes (ISGs), transforming growth factor-beta (TGFB), interleukin 10 (IL10), and arginase-1 (ARG1), configuring one of the most rapid immune responses to early pregnancy. This review focus on the local and peripheral immune responses during early pregnancy in ruminants, mainly the PMNs function in the immune system.

Conceptus-modulated innate immune function during early pregnancy in ruminants: a review

This review focuses on the innate immune events modulated by conceptus signaling during early pregnancy in ruminants. Interferon-tau (IFN-τ) plays a role in the recognition of pregnancy in ruminants, which involves more than the inhibition of luteolytic pulses of PGF2α to maintain corpus luteum function. For successful pregnancy establishment, the allogenic conceptus needs to prevent rejection by the female. Therefore, IFN-τ exerts paracrine and endocrine actions to regulate the innate immune system and prevent conceptus rejection. Additionally, other immune regulators work in parallel with IFN-τ, such as the pattern recognition receptors (PRR). These receptors are activated during viral and bacterial infections and in early pregnancy, but it remains unknown whether PPR expression and function are controlled by IFN-τ. Therefore, this review focuses on the main components of the innate immune response that are involved with early pregnancy and their importance to avoid conceptus rejection.

Feasibility and accuracy of using different methods to detect pregnancy by conceptus-stimulated genes in dairy cattle

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Peripheral blood mononuclear cells (PBMC) are the best biomarker for pregnancy prediction on d 20 after timed AI.

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An abundance of ISG15 was observed in pregnant dairy females in PBMC, total blood leukocytes, and cervical cells.

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Abundance of LGALS3BP is not good biomarker for determination of pregnancy status using any cell type.

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Total milk leukocytes are not useful for detection of genes stimulated by early pregnancy.

Development of new methods for early diagnosis of pregnancy can be important to increase the reproductive efficiency and profitability of dairy herds. The bovine conceptus secretes IFN-τ that stimulates the transcription of several genes in circulating immune cells and extrauterine tissues. The aims of this study were to evaluate the mRNA abundance for pregnancy predictability of a classic gene stimulated by IFN-τ (ISG15) and a novel potential pregnancy marker (LGALS3BP) in peripheral blood mononuclear cells (PBMC), total blood leukocytes (TBL) or milk leukocytes (TML), and cervical cells (CC) on d 20 after timed artificial insemination (TAI) in dairy cattle. Eighteen Holstein females (12 cows and 6 heifers) were submitted to an estrous synchronization protocol for TAI (d 0). On d 20 post-TAI, blood samples were collected from coccygeal vessels for isolation of PBMC and in Tempus Blood RNA tubes (Applied Biosystems) for TBL. Samples of CC were collected using a cytological brush, and the TML were isolated from milk samples collected before routine milking. Pregnancy diagnosis was performed on d 30 post-TAI using transrectal ultrasonography, and females were classified as pregnant (n = 8) or nonpregnant (n = 10). Total RNA was extracted and mRNA abundance of target genes (ISG15 and LGALS3BP) was quantified by reverse-transcription quantitative PCR and normalized in relation to reference genes. Data were analyzed by ANOVA using the MIXED procedure of SAS (SAS Institute Inc.). The mRNA abundance of ISG15 was greater in pregnant than in nonpregnant animals for PBMC, TBL, and CC. No difference was detected for TML based on pregnancy status. For LGALS3BP mRNA abundance, no difference was detected between pregnant and nonpregnant animals for PBMC, TBL, and TML, but a tendency for greater abundance in pregnant animals was observed for CC. The fold change for ISG15 in each pregnant cow related to the mean of nonpregnant animals was 2.73 ± 0.31, 3.40 ± 2.17, 1.64 ± 0.29, and 0.005 ± 0.002 for PBMC, CC, TBL, and TML, respectively. The fold change for LGALS3BP in each pregnant cow related to the mean of nonpregnant animals was 0.97 ± 0.38, 1.77 ± 0.39, 0.20 ± 0.08, and 0.70 ± 0.11 for PBMC, CC, TBL, and TML, respectively. The receiver operating characteristic curve analysis indicated that ISG15 abundance predicted pregnancy in PBMC (area under curve, AUC = 0.92) and CC (AUC = 0.77) but not in TBL (AUC = 0.72) or TML (AUC = 0.52). In conclusion, mRNA abundance for ISG15 in PBMC was the best predictor for pregnancy at d 20 post-TAI, whereas TBL and TML were not good predictors of pregnancy on d 20 post-TAI. The mRNA abundance of LGALS3BP was not associated with pregnancy status in any type of cell evaluated.

Comparison of the Ability of High and Low Virulence Strains of Non-cytopathic Bovine Viral Diarrhea Virus-1 to Modulate Expression of Interferon Tau Stimulated Genes in Bovine Endometrium

Bovine Viral Diarrhea virus (BVDV) is a pestivirus with a single-stranded, positive sense RNA genome. It is endemic in many cattle populations, causing major economic losses in part due to reduced fertility. BVDV exhibits great genetic diversity and is classified as type 1 or 2 (BVDV-1, BVDV-2) with either non-cytopathogenic (ncp) or cytopathogenic (cp) biotypes. Differing strains of ncpBVDV differ in virulence, affecting clinical outcome. BVDV replicates in the reproductive tract, affecting host immunity and embryo survival. This study used an in vitro model of primary bovine endometrial cell cultures to compare the effects of two BVDV ncp type 1a strains of differing virulence (termed HO and KY) on endometrial transcription of candidate interferon stimulated genes (ISG) using qPCR. Half the cultures were stimulated with interferon tau (IFNT, the conceptus produced pregnancy recognition factor) in the presence or absence of viral infection. Cultures were replicated on cells from 10 BVDV-free cows. IFNT treatment stimulated transcription of 10 candidate ISGs, whereas both ncpBVDV-1 strains alone inhibited transcription of 8/10 ISGs. In combined BVDV-1+IFNT cultures, the stimulatory effect of IFNT on expression of GBP4, ISG15, HERC5, RSAD2, IFIH1, IFIT3, and MX1 was significantly inhibited by HO, but only ISG15, RSAD2, IFI27, and IFIT3 were decreased by KY. Inhibition by HO was generally greater. The IFNT-induced expression of TRIM56 was, however, increased by HO. These data show that HO, the more virulent ncpBVDV-1 strain, has a greater capacity to inhibit key antiviral pathways. These differences need confirmation at the protein level but may influence immune tolerance of the host. They could also reduce fertility by increasing uterine susceptibility to bacterial infection and disrupting IFNT-mediated pregnancy recognition.

New approaches to diagnose and target reproductive failure in cattle

Reproductive failure and pregnancy loss in cattle are some of the largest economic burdens to cattle producers and one of most perplexing factors influencing management decisions. Pregnancy loss may occur at any point during gestation with the largest percentage of loss occurring in the first 30 days and, subsequently, decreasing as the pregnancy progresses. Losses may be attributed to numerous factors, predisposed issues or environmental conditions such as nutritional stressors or disease. From a research perspective, determining the exact causes of pregnancy loss or embryonic mortality in cattle have been difficult, due to limitations of accurately determining early gestation pregnancy status. Until methods that precisely determine embryo success early in gestation are available, our understanding of in vivo pregnancy loss will lack clarity necessary to develop management strategies to decrease such loss. In this review, we will briefly discuss the pivotal periods of pregnancy loss affecting beef and dairy cattle, methods and technologies to determine pregnancy status and embryo viability and potential opportunities to decrease reproductive failure.

Applied use of interferon-tau stimulated genes expression in polymorphonuclear cells to detect pregnancy compared to other early predictors in beef cattle

We aimed to evaluate the accuracy of Interferon-tau stimulated genes (ISG) abundance in peripheral blood polymorphonuclear cells (PMNs) on D20 after fixed-time artificial insemination (FTAI; D0) as a pregnancy diagnosis method against CL evaluation by Doppler ultrasonography and progesterone (P4) concentrations on D20, as well as Pregnancy Associated Glycoproteins (PAG) concentrations on D25. Additionally, we evaluated the potential of ISG abundance in PMNs as pregnancy loss predictors. Nelore heifers (n = 103) and cows (n = 144) underwent estrous synchronization and were artificially inseminated on D0. Pregnancy was diagnosed by B-mode ultrasonography on D30 and D70, and after the final diagnosis, females were classified in four groups: Pregnant; Non-pregnant; Functional CL on D20 but non-pregnant (CL-NP) and Pregnancy loss between D30 and D70 (PL). After determining cutoff values, the Sensitivity (SE), Specificity (SP), Positive Predictive Value (PPV), Negative Predictive Value (NPV) and Accuracy (ACC) were determined for each method. All methods were classified as significant (P < 0.05) predictors of pregnancy. Both ISG expression and PAG concentrations were greater (P < 0.05) in pregnant females than in non-pregnant and CL-NP females but did not differ (P > 0.05) from the PL group. ISG15 expression was greater (P < 0.05) in heifers than in cows, but this difference was not found in OAS1 expression and PAG concentrations. All the methods evaluated were proven to be adequate predictors of pregnancy, but greater accuracies were obtained through PAG concentrations and Doppler-US, due to the decreased number of false positive and false negative results.