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.

Analysis of the transcriptome of bovine endometrial cells isolated by laser micro-dissection (1): specific signatures of stromal, glandular and luminal epithelial cells

BACKGROUND

A number of studies have examined mRNA expression profiles of bovine endometrium at estrus and around the peri-implantation period of pregnancy. However, to date, these studies have been performed on the whole endometrium which is a complex tissue. Consequently, the knowledge of cell-specific gene expression, when analysis performed with whole endometrium, is still weak and obviously limits the relevance of the results of gene expression studies. Thus, the aim of this study was to characterize specific transcriptome of the three main cell-types of the bovine endometrium at day-15 of the estrus cycle.

RESULTS

In the RNA-Seq analysis, the number of expressed genes detected over 10 transcripts per million was 6622, 7814 and 8242 for LE, GE and ST respectively. ST expressed exclusively 1236 genes while only 551 transcripts were specific to the GE and 330 specific to LE. For ST, over-represented biological processes included many regulation processes and response to stimulus, cell communication and cell adhesion, extracellular matrix organization as well as developmental process. For GE, cilium organization, cilium movement, protein localization to cilium and microtubule-based process were the only four main biological processes enriched. For LE, over-represented biological processes were enzyme linked receptor protein signaling pathway, cell-substrate adhesion and circulatory system process.

CONCLUSION

The data show that each endometrial cell-type has a distinct molecular signature and provide a significantly improved overview on the biological process supported by specific cell-types. The most interesting result is that stromal cells express more genes than the two epithelial types and are associated with a greater number of pathways and ontology terms.

Multi-scale alignment of respiratory cilia and its relation to mucociliary function

The tracheobronchial tree is lined by a mucociliary epithelium containing millions of multiciliated cells. Their integrated oscillatory activity continuously propels an overlying pollution-protecting mucus layer in cranial direction, leading to mucociliary clearance - the primary defence mechanism of the airways. Mucociliary transport is commonly thought to co-emerge with the collective ciliary motion pattern under appropriate geometrical and rheological conditions. Proper ciliary alignment is therefore considered essential to establish mucociliary clearance in the respiratory system. Here, we used volume electron microscopy in combination with high-speed reflection contrast microscopy in order to examine ciliary orientation and its spatial organization, as well as to measure the propagation direction of metachronal waves and the direction of mucociliary transport on bovine tracheal epithelia with reference to the tracheal long axis (TLA). Ciliary orientation is measured in terms of the basal body orientation (BBO) and the axonemal orientation (AO), which are commonly considered to coincide, both equivalently indicating the effective stroke as well as the mucociliary transport direction. Our results, however, reveal that only the AO is in line with the mucociliary transport, which was found to run along a left-handed helical trajectory, whereas the BBO was found to be aligned with the TLA. Furthermore, we show that even if ciliary orientation remains consistent between adjacent cells, ciliary orientation exhibits a gradual shift within individual cells. Together with the symplectic beating geometry, this intracellular orientational pattern could provide for the propulsion of highly viscous mucus and likely constitutes a compromise between efficiency and robustness.

Phenotyping ciliary dynamics and coordination in response to CFTR-modulators in Cystic Fibrosis respiratory epithelial cells

Personalized approaches for systematically assessing ciliary beat dynamics and for drug testing would improve the challenging task of diagnosing and treating respiratory disorders. In this pilot study, we show how multiscale differential dynamic microscopy (multi-DDM) can be used to characterize collective ciliary beating in a non-biased automated manner. We use multi-DDM to assess the efficacy of different CFTR-modulating drugs in human airway epithelial cells derived from subjects with cystic fibrosis (ΔF508/ΔF508 and ∆F508/-) based on ciliary beat frequency and coordination. Similar to clinical observations, drug efficacy is variable across donors, even within the same genotype. We show how our assay can quantitatively identify the most efficient drugs for restoring ciliary beating for each individual donor. Multi-DDM provides insight into ciliary beating responses following treatment with drugs, and has application in the broader context of respiratory disease and for drug screening.

Personalized approaches to diagnosis and treatment monitoring could improve the management of cystic fibrosis patients. Here the authors show that multiscale differential dynamic microscopy can assess changes in cilia beating dynamics and coordination in patient-derived airway epithelial cells, in response to different CFTR-modulating drugs, in a patient-specific manner.

Determination of host proteins composing the microenvironment of coronavirus replicase complexes by proximity-labeling

Positive-sense RNA viruses hijack intracellular membranes that provide niches for viral RNA synthesis and a platform for interactions with host proteins. However, little is known about host factors at the interface between replicase complexes and the host cytoplasm. We engineered a biotin ligase into a coronaviral replication/transcription complex (RTC) and identified >500 host proteins constituting the RTC microenvironment. siRNA-silencing of each RTC-proximal host factor demonstrated importance of vesicular trafficking pathways, ubiquitin-dependent and autophagy-related processes, and translation initiation factors. Notably, detection of translation initiation factors at the RTC was instrumental to visualize and demonstrate active translation proximal to replication complexes of several coronaviruses. Collectively, we establish a spatial link between viral RNA synthesis and diverse host factors of unprecedented breadth. Our data may serve as a paradigm for other positive-strand RNA viruses and provide a starting point for a comprehensive analysis of critical virus-host interactions that represent targets for therapeutic intervention.

Coronaviruses can infect the nose and throat and are a main cause of the common cold. Infections are usually mild and short-lived, but sometimes they can turn nasty. In 2002 and 2012, two dangerous new coronaviruses emerged and caused diseases known as SARS and MERS. These viruses caused much more serious symptoms and in some cases proved deadly. The question is, why are some coronaviruses more dangerous than others? Scientists know that the body's response to virus infection can make a difference to whether someone had mild or severe disease. So, to understand why some coronaviruses cause a cold and others kill, they also need to learn how people react to virus infection.

Coronaviruses hijack membranes inside cells and turn them into virus factories. Within these factories, the viruses build molecular machinery called replicase complexes to copy their genetic code, which is needed for the next generation of virus particles. The viruses steal and repurpose proteins from their host cell that will assist in the copying process. However, scientists do not yet know which host proteins are essential for the virus to multiply. So, to find out, V’kovski et al. developed a way to tag any host protein that came near the virus factories.

The new technique involved attaching an enzyme called a biotin ligase to the replicase complex. This enzyme acts as a molecular label gun, attaching a chemical tag to any protein that comes within ten nanometres. The label gun revealed that more than 500 different proteins come into contact with the replicase complex. To find out what these proteins were doing, the next step was to switch off their genes one by one. This revealed the key cell machinery that coronaviruses hijack when they are replicating. It included the cell's cargo transport system, the waste disposal system, and the protein production system. Using these systems allows the viruses to copy their genetic code next to machines that can turn it straight into viral proteins.

These new results provide clues about which proteins viruses actually need from their host cells. They also do not just apply to coronaviruses. Other viruses use similar strategies to complete their infection cycle. These findings could help researchers to understand more generally about how viruses multiply. In the future, this knowledge could lead to new ways to combat virus infections.

The Small-Compound Inhibitor K22 Displays Broad Antiviral Activity against Different Members of the Family Flaviviridae and Offers Potential as a Panviral Inhibitor

The virus family Flaviviridae encompasses several viruses, including (re)emerging viruses which cause widespread morbidity and mortality throughout the world. Members of this virus family are positive-strand RNA viruses and replicate their genome in close association with reorganized intracellular host cell membrane compartments. This evolutionarily conserved strategy facilitates efficient viral genome replication and contributes to evasion from host cell cytosolic defense mechanisms. We have previously described the identification of a small-compound inhibitor, K22, which exerts a potent antiviral activity against a broad range of coronaviruses by targeting membrane-bound viral RNA replication. To analyze the antiviral spectrum of this inhibitor, we assessed the inhibitory potential of K22 against several members of the Flaviviridae family, including the reemerging Zika virus (ZIKV). We show that ZIKV is strongly affected by K22. Time-of-addition experiments revealed that K22 acts during a postentry phase of the ZIKV life cycle, and combination regimens of K22 together with ribavirin (RBV) or interferon alpha (IFN-α) further increased the extent of viral inhibition. Ultrastructural electron microscopy studies revealed severe alterations of ZIKV-induced intracellular replication compartments upon infection of K22-treated cells. Importantly, the antiviral activity of K22 was demonstrated against several other members of the Flaviviridae family. It is tempting to speculate that K22 exerts its broad antiviral activity against several positive-strand RNA viruses via a similar mechanism and thereby represents an attractive candidate for development as a panviral inhibitor.

Can the antral follicular count modulate the gene expression of bovine oviducts in Aberdeen Angus and Nelore heifers?

The number of visible ovarian antral follicles (antral follicle count—AFC) is repeatable in bovine individuals, but highly variable between animals, and with differences between Bos taurus and Bos indicus breeds. Several studies have tried to determine the correlation between AFC and increased fertility in cattle. While the impacts of AFC on embryo production, hormonal levels, and pregnancy rates have been described, the molecular effects of AFC on bovine oviducts have not yet been investigated. Here, the aim was to investigate the impact of breeds, such as Aberdeen Angus and Nelore heifer with high or low AFC, on abundance of transcripts and protein related to oviductal transport, sperm reservoir formation, monospermy control, and gamete interaction in the oviducts. In summary, the ovulation side was the major factor that affected transcript abundance on bovine oviducts. However, a discreet effect among AFC and cattle breeds was also observed. Based on this, we concluded and reinforced here that differential microenvironments between ipsilateral and contralateral oviducts have a major effect on modulating the transcripts related to oviductal transport, sperm reservoir formation, monospermy control, and gamete interaction. However, we cannot exclude that there is minimal effect of AFC or breed on regulation of some genes (such as AGTR1, ACE1, FUCA1, and VEGFA) in bovine oviducts.

Assessing the Collective Dynamics of Motile Cilia in Cultures of Human Airway Cells by Multiscale DDM

The technique of differential dynamic microscopy is extended here, showing that it can provide a powerful and objective method of video analysis for optical microscopy videos of in vitro samples of live human bronchial epithelial ciliated cells. These cells are multiciliated, with motile cilia that play key physiological roles. It is shown that the ciliary beat frequency can be recovered to match conventional analysis, but in a fully automated fashion. Furthermore, it is shown that the properties of spatial and temporal coherence of cilia beat can be recovered and distinguished, and that if a collective traveling wave (the metachronal wave) is present, this has a distinct signature and its wavelength and direction can be measured.

High-content analysis of factors affecting gold nanoparticle uptake by neuronal and microglial cells in culture

Owing to their ubiquitous distribution, expected beneficial effects and suspected adverse effects, nanoparticles are viewed as a double-edged sword, necessitating a better understanding of their interactions with tissues and organisms. Thus, the goals of the present study were to develop and present a method to generate quantitative data on nanoparticle entry into cells in culture and to exemplarily demonstrate the usefulness of this approach by analyzing the impact of size, charge and various proteinaceous coatings on particle internalization. N9 microglial cells and both undifferentiated and differentiated SH-SY5Y neuroblastoma cells were exposed to customized gold nanoparticles. After silver enhancement, the particles were visualized by epipolarization microscopy and analysed by high-content analysis. The value of this approach was substantiated by assessing the impact of various parameters on nanoparticle uptake. Uptake was higher in microglial cells than in neuronal cells. Only microglial cells showed a distinct size preference, preferring particles with a diameter of 80 nm. Positive surface charge had the greatest impact on particle uptake. Coating with bovine serum albumin, fetuin or protein G significantly increased particle internalization in microglial cells but not in neuronal cells. Coating with wheat germ agglutinin increased particle uptake in both N9 and differentiated SH-SY5Y cells but not in undifferentiated SH-SY5Y cells. Furthermore, internalization was shown to be an active process and indicators of caspase-dependent apoptosis revealed that gold nanoparticles did not have any cytotoxic effects. The present study thus demonstrates the suitability of gold nanoparticles and high-content analysis for assessing numerous variables in a stringently quantitative and statistically significant manner. Furthermore, the results presented herein showcase the feasibility of specifically targeting nanoparticles to distinct cell types.

Modifications of carbohydrate residues in the sheep oviductal ampulla after superovulation

Epithelium of oviductal ampulla was studied in normal and in superovulated sheep using morphologic analysis and lectin glycohistochemistry. The lining epithelium consisted of two types of cells, ciliated and nonciliated cells. Unlike superovulated samples, the nonciliated cells from control ewes showed apical protrusions indicating an apocrine secretory activity. The ciliated cells showed lectin-binding sites mainly at the level of the cilia which bound all the used lectins except Peanut agglutinin, suggesting the lack of glycans terminating with Galβ1,3GalNAc. In superovulated specimens, the ciliated cells with high mannosylated glycans Concanavalin A (Con A) and GlcNAc and GalNac termini Griffonia simplicifolia agglutinin II (GSA II) and Dolicurus biflorus agglutinin (DBA) decreased. The luminal surface of nonciliated cells showed all investigated sugar residues in controls, whereas it was lacking in high mannosylated (Con A) and terminal GalNAcα1,3(LFucα1,2)Galβ1,3/4GlcNAcβ1 sequence (DBA) in superovulated ewes. Apical protrusions from control ampullae nonciliated cells showed glycans containing mannose, GlcNac, GalNAc, galactose, and α2,3-linked sialic acid (Con A, KOH-sialidase- Wheat germ agglutnin [WGA], GSA II, SBA, Griffonia simplicifolia agglutinin-isolectin B4 [GSA I-B4], Maackia amurensis agglutinin II [MAL II]). The supranuclear cytoplasm of nonciliated cells expressed terminal GlcNAc (GSA II) in all specimens, also O-linked glycans (mucin-type glycans) with GalNAc and sialic acid termini (Helix pomatia agglutinin [HPA] and MAL II) in control animals, and also N-linked glycans with fucose, galactose, lactosamine, and α2,3-linked sialic acid termini (Ulex europaeus agglutinin I [UEA I], GSA I-B4, Ricinus communis agglutinin120 [RCA120], and Sambucus nigra agglutinin [SNA] ) in superovulated ewes. These results report for the first time that the superovulation treatment affects the secretory activity and the glycan pattern of the epithelium lining the sheep oviductal ampulla.