MiRNA profiling of plasma-derived exosomes from dairy cows during gestation

Recent advances in early pregnancy loss diagnosis in dairy cows: New approaches

Early pregnancy loss is a primary cause of low reproductive rates in dairy cows, posing severe economic losses to dairy farming. The accurate diagnosis of dairy cows with early pregnancy loss allows for oestrus synchronization, shortening day open, and increasing the overall conception rate of the herd. Several techniques are available for detecting early pregnancy loss in dairy cows, including rectal ultrasound, circulating blood progesterone, and pregnancy-associated glycoproteins (PAGs). Yet, there is a need to improve on existing techniques and develop novel strategies to identify cows with early pregnancy loss accurately. This manuscript reviews the applications of rectal ultrasound, circulating blood progesterone concentration, and PAGs in the diagnosis of pregnancy loss in dairy cows. The manuscript also discusses the recent progress of new technologies, including colour Doppler ultrasound (CDUS), interferon tau-induced genes (ISGs), and exosomal miRNA in diagnosing pregnancy loss in dairy cows. This study will provide an option for producers to re-breed cows with pregnancy loss, thereby reducing the calving interval and economic costs. Meanwhile, this manuscript might also act as a reference for exploring more economical and precise diagnostic technologies for early pregnancy loss in dairy cows.

Curcumin Changed the Number, Particle Size, and miRNA Profile of Serum Exosomes in Roman Laying Hens under Heat Stress

Exosomes have the ability to transport RNA/miRNAs and possess immune modulatory functions. Heat stress, a significant limiting factor in the poultry industry, can induce oxidative stress and suppress the immune responses of laying hens. In this study, we investigated the expression profiles of serum exosomes and their miRNAs in Roman laying hens who were fed a diet with either 0 or 200 mg/kg curcumin under heat stress conditions. The numbers of exosomes were significantly higher in both the HC (heat stress) and HT (heat stress with 200 mg/kg curcumin) groups compared to the NC (control) group and NT (control with 200 mg/kg curcumin) group (p < 0.05). Additionally, we observed that the most prevalent particle diameters were 68.75 nm, 68.25 nm, 54.25 nm, and 60.25 nm in the NC, NT, HC, and HT groups, respectively. From our sRNA library analysis, we identified a total of 863 unique miRNAs; among them, we screened out for subsequent bioinformatics analysis a total of 328 gga-miRNAs(chicken miRNA from the miRbase database). The KEGG pathways that are associated with target genes which are regulated by differentially expressed miRNAs across all four groups at a p-value < 0.01 included oxidative phosphorylation, protein export, cysteine and methionine metabolism, fatty acid degradation, ubiquitin-mediated proteolysis, and cardiac muscle contraction. The above findings suggest that curcumin could mitigate heat-induced effects on laying hens by altering the miRNA expression profiles of serum exosomes along with related regulatory pathways.

Emerging role of extracellular vesicles in veterinary practice: novel opportunities and potential challenges

Extracellular vesicles are nanoscale vesicles that transport signals between cells, mediating both physiological and pathological processes. EVs facilitate conserved intercellular communication. By transferring bioactive molecules between cells, EVs coordinate systemic responses, regulating homeostasis, immunity, and disease progression. Given their biological importance and involvement in pathogenesis, EVs show promise as biomarkers for veterinary diagnosis, and candidates for vaccine production, and treatment agents. Additionally, different treatment or engineering methods could be used to boost the capability of extracellular vesicles. Despite the emerging veterinary interest, EV research has been predominantly human-based. Critical knowledge gaps remain regarding isolation protocols, cargo loading mechanisms, in vivo biodistribution, and species-specific functions. Standardized methods for veterinary EV characterization and validation are lacking. Regulatory uncertainties impede veterinary clinical translation. Advances in fundamental EV biology and technology are needed to propel the veterinary field forward. This review introduces EVs from a veterinary perspective by introducing the latest studies, highlighting their potential while analyzing challenges to motivate expanded veterinary investigation and translation.

Assessing the Differential Abundance of Maternal Circulating MicroRNAs or Interferon-Stimulated Genes with Early Pregnancy

Interferon-stimulated genes (ISG) and microRNA (miRNA) present in maternal circulation have been reported to be diagnostic of pregnancy in cattle prior to day (d)30 of gestation. The objective of this study was to assess specific ISG and miRNA abundance on d 18 of gestation. Cattle were subjected to estrous synchronization and artificially inseminated to a single Angus sire. At time of insemination (d 0) and d 18 post-insemination, blood was collected and total RNA isolated. Differential abundance (DA) in specific ISG and miRNA between d 0 and d 18 samples in pregnant (n = 10) and open (n = 10) cows were assessed via RT-qPCR. The relative Ct values were normalized using abundance of cyclophilin or the geometric mean of specific miRNA for the ISG and miRNA genes of interest, respectively. The DA of the ISG were increased due to pregnancy (p < 0.05); however, there was no expected day of gestation by pregnancy interaction. Relative abundance of Bta-miR-16 increased on d18 regardless of pregnancy status (p < 0.05). None of the miRNA evaluated in this study were associated with pregnancy status. These data indicate that certain ISG may serve as early indicators of pregnancy in cattle, but abundance of the miRNA does not.

Extracellular vesicles-encapsulated microRNA in mammalian reproduction: A review

Extracellular vesicles (EVs) are nanoscale cell-derived lipid vesicles that participate in cell-cell communication by delivering cargo, including mRNAs, proteins and non-coding RNAs, to recipient cells. MicroRNA (miRNA), a non-coding RNA typically 22 nucleotides long, is crucial for nearly all developmental and pathophysiological processes in mammals by regulating recipient cells gene expression. Infertility is a worldwide health issue that affects 10-15% of couples during their reproductive years. Although assisted reproductive technology (ART) gives infertility couples hope, the failure of ART is mainly unknown. It is well accepted that EVs-encapsulated miRNAs have a role in different reproductive processes, implying that these EVs-encapsulated miRNAs could optimize ART, improve reproductive rate, and treat infertility. As a result, in this review, we describe the present understanding of EVs-encapsulated miRNAs in reproduction regulation.

Analysis of circulating microRNA during early gestation in Japanese black cattle

Circulating microRNAs (miRNAs) have been used as biomarkers for various diseases and physiological conditions in humans and mice; studies in domestic animals, particularly cattle, are limited. The importance of early pregnancy diagnosis (especially within the 21-d cow estrous cycle) in the livestock industry is extremely high. This study compared the circulating miRNAs in bred non-pregnant and pregnant Japanese Black cows, explored miRNAs as biomarkers for early pregnancy diagnosis, and established a measurement system that included selecting an appropriate reference miRNA and determining the effect of hemolysis on miRNA quantification in plasma. miRNA was extracted from the plasma of Japanese Black cows on day 21 after artificial insemination and subjected to a customized bovine oligonucleotide microarray for expression analysis. Differentially expressed miRNAs and reference miRNA candidates were selected and validated using reverse transcription-quantitative PCR (RT-qPCR). An appropriate endogenous reference miRNA for normalization was selected using NormFinder software. To evaluate the effect of hemolysis on miRNA quantification, hemolyzed samples were prepared using plasma from four cows in the estrous cycle and subjected to RT-qPCR. A total of 124 miRNAs were detected in bovine plasma by microarray analysis in bred non-pregnant and pregnant cows. The levels of five circulating miRNAs were significantly higher in pregnant cows than in bred non-pregnant cows, and 24 miRNAs were detected only in the pregnant group. NormFinder analysis and RT-qPCR validation showed that miR-2455 was an appropriate reference miRNA in the plasma of bred non-pregnant and pregnant Japanese Black cows, and miR-19b, miR-25, miR-29a, and miR-148a were significantly higher in the pregnant group. These four circulating miRNAs did not change during the estrous cycle and were less affected by hemolysis. In the current study, we found four miRNAs, miR-19b, miR-25, miR-29a, and miR-148a, which were present at high levels in the plasma of pregnant Japanese Black cows. Since these miRNAs are less affected by hemolysis, they may potentially be used as biomarkers for early pregnancy diagnosis in cattle.

MicroRNAs: Potential biomarkers for reproduction, diagnosis, prognosis, and therapeutic in domestic animals

MicroRNA (miRNAs) are small non-coding RNA molecules involved in a wide range of biological processes through the post-transcriptional regulation of gene expression. Most studies evaluated microRNA expression in human, and despite fewer studies in veterinary medicine, this topic is one of the most exciting areas of modern veterinary medicine. miRNAs showed to be part of the pathogenesis of diseases and reproduction physiology in animals, making them biomarkers candidates. This review provides an overview of the current knowledge regarding miRNAs' role in reproduction and animal diseases, diagnostic and therapy.

MiRNA-mRNA Integration Analysis Reveals the Regulatory Roles of MiRNAs in Shell Pigmentation of the Manila clam (Ruditapes philippinarum)

The shell color of the Manila clam (Ruditapes philippinarum) is an economically important trait. We used high-throughput sequencing and transcriptome analysis to study the molecular mechanisms that underlie shell color formation and regulation in this species. We constructed small RNA libraries from mantle tissues from four shell color strains of Manila clam, subjected them to high-throughput sequencing. Notably, the results suggested that a number of pigment-associated genes including Mitf, HERC2, were negatively regulated by nvi-miR-2a, tgu-miR-133-3p, respectively. They might be involved in melanin formation via the activation of the melanogenesis pathway. And aae-miR-71-5p and dme-miR-7-5p linked to shell formation-related genes such as Calmodulin and IMSP3 were considered to participate in the calcium signaling pathway. We then used quantitative PCR to verify the candidate miRNAs and target genes in different shell color groups. Our results indicated that miR-7, miR-71, and miR-133 may regulate target mRNAs to participate in shell color pigmentation. These results provide the foundation to further characterize miRNA effects on the regulation of shell color and have significant implications for the breeding of new varieties of clams.

M2 Macrophage-derived exosomal miR-501 contributes to pubococcygeal muscle regeneration

Pubococcygeal muscle injury can lead to stress urinary incontinence (SUI). M2 macrophages play a crucial role in myoblast differentiation during injured muscle regeneration. However, the underlying mechanism remains unclear. Recently, exosomes have attracted increasing attention due to their mediation of cell-to-cell communication. In this study, we found that M2 macrophages extensively infiltrated the pubococcygeal muscle on day 5 after injury (VD5) in vivo. Then, C2C12 myoblasts were treated with M2 macrophage-derived exosomes (M2-EXO) and the results revealed that these exosomes could promote myotube formation. MiR-501 was identified as one of the abundant microRNAs (miRNAs) selectively loaded in M2-EXO, and subsequently confirmed to promote C2C12 myoblast differentiation by targeting YY1. Moreover, in vivo experiments showed that M2-EXO improves the inflammatory cell infiltration and have a therapeutic effect on damaged pubococcygeal muscle in SUI models. Collectively, our present results provide new insights into the promyogenic mechanism of M2 macrophages and prove that M2 macrophage exosomal miR-501 may represent a potential therapeutic to promote recovery from diseases caused by muscle injury, including SUI.

Screening and identification of microRNAs from plasma-derived extracellular vesicles (EVs) of Dazu black goat (Capra hircus) in early pregnant stages

Previous studies have shown that extracellular vesicles (EVs) containing proteins, lipids, nucleic acids and other biological components exist in all kinds of body fluids. EVs, as an intercellular communication carrier, regulate the functions of its target cells by transporting biomacromolecules between cells. In this study, a total of six female Dazu black goats were divided into NP group (NP, non-pregnant group) and P30 (P30, 30-day pregnant group). The goats in NP group (n = 3) were in estrus, but failed to fertilize; the other goats in P30 group (n = 3) were fertilized by natural mating. Firstly, goats plasma-derived EVs were isolated using ultracentrifugation. Secondly, EVs were identified by transmission electron microscope (TEM), dynamic light scattering (DLS), and by testing its markers (CD9 and CD63) using west blotting in NP and P30 groups, respectively. Thirdly, EVs related miRNAs were sequenced and analyzed by bioinformatics method. Data shows that miR-31-5p, miR-137-3p, novel_miR_1355, novel_miR_734 and novel_miR_736 exclusively were expressed in P30 group. Their target genes were significantly enriched in the axon guidance, the Notch signaling pathway, the Wnt signaling pathway, tight junction and the Hippo signaling pathway. And miRNA-mRNA interactive network analysis reveals potential regulatory functions of miRNAs for goat during early pregnancy. These findings provided theretical references for studying the regulation of plasma-derived EVs between the fetal and placental development, and these candidate miRNAs identified might be as markers for diagnosis of goat early pregnancy.

Analysis of miRNA expression changes in bovine endometrial stromal cells treated with lipopolysaccharide

After parturition, bovine uterine stromal cells are often exposed to complex bacterial and viral stimuli owing to epithelial cell rupture, resulting in an inflammatory response. In this study, we used an in vitro model to study the response of bovine endometrial stromal cells to inflammatory mediators and the associated regulated microRNAs in response to lipopolysaccharide. Lipopolysaccharide (LPS) is a bacterial wall component in gram-negative bacteria that causes inflammation upon immune recognition, which is used to create in vitro inflammation models. Thus, we used high-throughput RNA sequencing to identify miRNAs that may have an anti-inflammatory role in the LPS-induced inflammatory response. Two groups of bovine uterine cells were treated with phosphate buffer saline (PBS) and LPS, respectively. Compared with the control (PBS) group, the LPS-treated group had 219 differentially expressed miRNAs, of which 113 were upregulated, and 106 were downregulated. Gene ontology enrichment analysis revealed that the target genes of differentially expressed miRNAs were significantly enriched in several activities, such as transferase activity, small molecule binding, and protein binding. Kyoto Encyclopedia of Genes and Genomes pathway analysis indicated that the target genes of differential miRNAs were significantly enriched in fluid shear stress and atherosclerosis, MAPK signaling pathway, TNF signaling pathway. By analyzing differentially expressed miRNAs, we found that miR-200c, miR-1247-3p, and let-7b are directly related to the inflammatory response. For instance, miR-200c target genes (MAP3K1, MAP4K3, MAPKAPK5, MAP3K8, MAP3K5) and let-7b target genes (CASP3, IL13, MAPK8, CXCL10) were significantly enriched in the MAPK and IL-17 signaling pathways, respectively. In summary, our research provides insight into the molecular mechanism underlying LPS-induced inflammation in vitro, which may unveil new targets for the treatment of endometritis.

Exosomal Cargo May Hold the Key to Improving Reproductive Outcomes in Dairy Cows

The reproductive status of dairy cows remains a challenge for dairy farmers worldwide, with impaired fertility linked to a significant reduction in herd profitability, due in part to impaired immunity, increased metabolic pressure, and longer postpartum anestrous interval (PPAI). Exosomes are nanovesicles released from a variety of cell types and end up in circulation, and carry proteins, bioactive peptides, lipids, and nucleic acids specific to the place of origin. As such, their role in health and disease has been investigated in humans and animals. This review discusses research into exosomes in the context of reproduction in dairy herds and introduces recent advances in mass-spectrometry (MS) based proteomics that have a potential to advance quantitative profiling of exosomal protein cargo in a search for early biomarkers of cattle fertility.

The promise of placental extracellular vesicles: models and challenges for diagnosing placental dysfunction in utero†

Monitoring the health of a pregnancy is of utmost importance to both the fetus and the mother. The diagnosis of pregnancy complications typically occurs after the manifestation of symptoms, and limited preventative measures or effective treatments are available. Traditionally, pregnancy health is evaluated by analyzing maternal serum hormone levels, genetic testing, ultrasonographic imaging, and monitoring maternal symptoms. However, researchers have reported a difference in extracellular vesicle (EV) quantity and cargo between healthy and at-risk pregnancies. Thus, placental EVs (PEVs) may help to understand normal and aberrant placental development, monitor pregnancy health in terms of developing placental pathologies, and assess the impact of environmental influences, such as infection, on pregnancy. The diagnostic potential of PEVs could allow for earlier detection of pregnancy complications via noninvasive sampling and frequent monitoring. Understanding how PEVs serve as a means of communication with maternal cells and recognizing their potential utility as a readout of placental health have sparked a growing interest in basic and translational research. However, to date, PEV research with animal models lags behind human studies. The strength of animal pregnancy models is that they can be used to assess placental pathologies in conjunction with isolation of PEVs from fluid samples at different time points throughout gestation. Assessing PEV cargo in animals within normal and complicated pregnancies will accelerate the translation of PEV analysis into the clinic for potential use in prognostics. We propose that appropriate animal models of human pregnancy complications must be established in the PEV field.

MicroRNA Milk Exosomes: From Cellular Regulator to Genomic Marker

Recent advances in ruminants' milk-derived exosomes (EXO) have indicated a role of microRNAs (miRNAs) in cell-to-cell communication in dairy ruminants. The miRNAs EXO retain peculiar mechanisms of uptake from recipient cells, which enables the selective delivery of cargos, with a specific regulation of target genes. Although many studies have been published on the miRNAs contained in milk, less information is available on the role of miRNAs EXO, which are considered stable over time and resistant to digestion and milk processing. Several miRNAs EXO have been implicated in the cellular signaling pathway, as in the regulation of immune response. Moreover, they exert epigenetic control, as extenuating the expression of DNA methyltransferase 1. However, the study of miRNAs EXO is still challenging due to the difficulty of isolating EXO. In fact, there are not agreed protocols, and different methods, often time-consuming, are used, making it difficult to routinely process a large number of samples. The regulation of cell functions in mammary glands by miRNAs EXO, and their applications as genomic markers in livestock, is presented.

Post-Translational Protein Deimination Signatures in Serum and Serum-Extracellular Vesicles of Bos taurus Reveal Immune, Anti-Pathogenic, Anti-Viral, Metabolic and Cancer-Related Pathways for Deimination

The bovine immune system is known for its unusual traits relating to immunoglobulin and antiviral responses. Peptidylarginine deiminases (PADs) are phylogenetically conserved enzymes that cause post-translational deimination, contributing to protein moonlighting in health and disease. PADs also regulate extracellular vesicle (EV) release, forming a critical part of cellular communication. As PAD-mediated mechanisms in bovine immunology and physiology remain to be investigated, this study profiled deimination signatures in serum and serum-EVs in Bos taurus. Bos EVs were poly-dispersed in a 70-500 nm size range and showed differences in deiminated protein cargo, compared with whole sera. Key immune, metabolic and gene regulatory proteins were identified to be post-translationally deiminated with some overlapping hits in sera and EVs (e.g., immunoglobulins), while some were unique to either serum or serum-EVs (e.g., histones). Protein-protein interaction network analysis of deiminated proteins revealed KEGG pathways common for serum and serum-EVs, including complement and coagulation cascades, viral infection (enveloped viruses), viral myocarditis, bacterial and parasitic infections, autoimmune disease, immunodeficiency intestinal IgA production, B-cell receptor signalling, natural killer cell mediated cytotoxicity, platelet activation and hematopoiesis, alongside metabolic pathways including ferroptosis, vitamin digestion and absorption, cholesterol metabolism and mineral absorption. KEGG pathways specific to EVs related to HIF-1 signalling, oestrogen signalling and biosynthesis of amino acids. KEGG pathways specific for serum only, related to Epstein-Barr virus infection, transcription mis-regulation in cancer, bladder cancer, Rap1 signalling pathway, calcium signalling pathway and ECM-receptor interaction. This indicates differences in physiological and pathological pathways for deiminated proteins in serum-EVs, compared with serum. Our findings may shed light on pathways underlying a number of pathological and anti-pathogenic (viral, bacterial, parasitic) pathways, with putative translatable value to human pathologies, zoonotic diseases and development of therapies for infections, including anti-viral therapies.

Challenges in studying preimplantation embryo-maternal interaction in cattle

A comprehensive understanding of the complex embryo-maternal interactions during the preimplantation period requires the analysis of the very early stages of pregnancy encompassing early embryonic development, maternal recognition and the events leading to implantation. Despite the fact that embryo development until blastocyst stage is somewhat autonomous (i.e., does not require contact with the maternal reproductive tract and can be successfully recapitulated in vitro), many studies on ruminant embryo production have focused on the fundamental question of why: (i) only 30%-40% of immature oocytes develop to the blastocyst stage and (ii) the quality of such blastocysts continually lags behind that of blastocysts produced in vivo. Clear evidence indicates that in vitro culture conditions are far from optimal with deficiencies being manifested in short- and long-term effects on the embryo. Thus, enhanced knowledge of mechanisms controlling embryo-maternal interactions would allow the design of novel strategies to improve in vitro embryo conditions and reproductive outcomes in cattle.

Intraluminal vesicles of binucleate trophoblast cell granules are a possible source of placental exosomes in ruminants

INTRODUCTION

Exosomes are membrane-bound small extracellular vesicles, which play important roles in intercellular communication, including the feto-maternal communication. Placenta-derived exosomes have been identified in maternal blood of a variety of species, including cattle and sheep.

METHODS

Transmission electron microscopy is used to characterize intraluminal vesicles in binucleate trophoblast cell secretory granules and extracellular vesicles in placentome samples from eight ruminant species of the bovidae and cervidae clades.

RESULTS

In all species the secretory granules of binucleate cells contain intraluminal vesicles of 40-70 nm diameter. After fusion of the binucleate trophoblast cells with cells of the uterine epithelium these vesicles are exocytosed together with the granule's secretory proteins. The vesicles are located at the basement membrane of the uterine epithelium and in the connective tissue underneath.

DISCUSSION

We suggest that these vesicles function as exosomes. Their function might be either locally in the maternal endometrial stroma or they could have systemic functions after entering the maternal blood. Earlier electron microscopical studies in other ruminants, including species of the most basic ruminant clade (tragulidae), indicate that the intraluminal vesicles are a general feature of ruminant binucleate trophoblast cell granules. Our findings suggest that ruminant BNC are a source of exosomes, which are released into the maternal organism and are thus a newly described type of feto-maternal communication in ruminants.