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

A case-control genome-wide association study of estimated breeding values for resistance to gastrointestinal nematodes in two local dairy sheep breeds

In sheep, gastrointestinal nematodes (GINs) can cause disease, reduced feed intake, and nutritional deficiencies. To counteract GINs, anthelmintics are widely used although it is well known they may enter the environment impacting ecosystems. In addition, anthelmintics resistance has rapidly developed and consequently, alternative approaches are crucial for profitable and sustainable sheep production. The occurrence of resistant individuals is mainly due to their intrinsic genetic diversity; therefore, the implementation of breeding plans for resistant animals may provide a promising strategy to reduce the use of anthelmintics. This study is aimed at identifying genomic regions involved in sheep resistance to GINs. To do this, faecal samples were collected from 642 Comisana and 323 Massese sheep over 3 years to assess Faecal Egg Counts, and Estimated Breeding Values (EBVs) for GIN resistance were estimated by a repeatability animal model. Then, EBVs in the 99.95th and 0.05th percentiles were used to identify the most and least "genetically resistant" individuals to GINs, using genotyped individuals with the Illumina OvineSNP50 beadchip. A genome-wide case-control analysis was performed retaining the most significant single nucleotide polymorphisms (SNPs) with a threshold of 0.005% for the false discovery rate. Genes and Quantitative Trait Loci overlapping significant SNPs were annotated and enriched respectively while genes have been also enriched for functional pathways. As a result, 13 genes on 12 chromosomes and 10 genes on 11 different chromosomes were identified in the Comisana and Massese breed, respectively. Among these, genes involved in the physiology or pathology of the gastrointestinal tract, in adaptive processes and in production traits, were detected. The enrichment analysis highlighted 36 significant pathways in the Comisana breed and 21 in the Massese breed. Many of these pathways were involved in the regulation of the immune response, drug metabolism and detoxification, and vitamin metabolism. Interestingly, pathways involved in vitamin and drug metabolism were also identified in previous research and have shown to play an active role in GIN resistance. In this study, we took advantage of the use of EBVs as a metric for GIN resistance in a case-control genome-wide framework and successfully identified several genomic regions that might be involved in the trait. The presence of overlapping functional pathways related to different genes in the two breeds seems to reinforce the idea of the polygenicity of this trait, and further studies are needed in order to make selection schemes an effective tool to contrast GINs.

A New Perspective on Pig Genetics and Breeding: microRNA

microRNA (miRNA) is a class of small non-coding RNA molecules that are widely expressed in organisms and play an important role in the regulation of gene expression at the post-transcriptional level. In recent years, researchers have begun to explore its effects on the development of domestic animals and have begun to think about its potential role in modern molecular breeding. Increasing evidence shows that miRNA play a central role in the regulation of pig fertility, pork product quality and disease resistance. Understanding the physiological mechanism of miRNA will be able to better guide future breeding work. In this paper, we will review the research progress of the function and mechanism of miRNA in combination with the above economic characteristics of pigs. The reported miRNA and their target genes were sorted out to evaluate their potential role in improving economic traits such as pig fertility, meat quality and disease resistance, to provide a reference for modern pig molecular breeding.

Exploring the role of microRNAs as diagnostic and prognostic biomarkers in canine mammary tumors

Canine mammary tumors (CMTs) represent a significant health concern in dogs, with a high incidence among intact female dogs. CMTs are a promising comparative model for human breast cancer, due to sharing several pathophysiological features. Additionally, CMTs have a strong genetic correlation with their human counterpart, including the expression of microRNAs (miRNAs). MiRNAs are a class of non-coding RNAs that play important roles in post-translational regulation of gene expression, being implicated in carcinogenesis, tumor progression, and metastasis. Moreover, miRNAs hold promise as diagnostic, prognostic, and metastatic biomarkers. Understanding the molecular mechanisms underlying CMTs is crucial for improving diagnosis, prognosis, and monitoring of treatments. Herein, we provide a comprehensive overview of the current knowledge on miRNAs in CMTs, highlighting their roles in carcinogenesis and their potential as biomarkers. Additionally, we highlight the current limitations and critically discuss the overarching challenges in this field, emphasizing the need for future research to translate miRNA findings into veterinary clinical practice.

A glimpse into the world of microRNAs and their putative roles in hard ticks

Ticks are important blood feeding ectoparasites that transmit pathogens to wildlife, domestic animals, and humans. Hard ticks can feed for several days to weeks, nevertheless they often go undetected. This phenomenon can be explained by a tick's ability to release analgesics, immunosuppressives, anticoagulants, and vasodilators within their saliva. Several studies have identified extracellular vesicles (EVs) as carriers of some of these effector molecules. Further, EVs, and their contents, enhance pathogen transmission, modulate immune responses, and delay wound healing. EVs are double lipid-membrane vesicles that transport intracellular cargo, including microRNAs (miRNAs) to recipient cells. miRNAs are involved in regulating gene expression post-transcriptionally. Interestingly, tick-derived miRNAs have been shown to enhance pathogen transmission and affect vital biological processes such as oviposition, blood digestion, and molting. miRNAs have been found within tick salivary EVs. This review focuses on current knowledge of miRNA loading into EVs and homologies reported in ticks. We also describe findings in tick miRNA profiles, including miRNAs packed within tick salivary EVs. Although no functional studies have been done to investigate the role of EV-derived miRNAs in tick feeding, we discuss the functional characterization of miRNAs in tick biology and pathogen transmission. Lastly, we propose the possible uses of tick miRNAs to develop management tools for tick control and to prevent pathogen transmission. The identification and functional characterization of conserved and tick-specific salivary miRNAs targeting important molecular and immunological pathways within the host could lead to the discovery of new therapeutics for the treatment of tick-borne and non-tick-borne human diseases.

Understanding Circular RNAs in Health, Welfare, and Productive Traits of Cattle, Goats, and Sheep

Circular RNAs (circRNAs) are unique noncoding RNA molecules, notable for their covalent closed-loop structures, which play a crucial role in regulating gene expression across a variety of biological processes. This review comprehensively synthesizes the existing knowledge of circRNAs in three key livestock species: Bos taurus (cattle), Ovis aries (sheep), and Capra hircus (goats). It focuses on their functional importance and emerging potential as biomarkers for disease detection, stress response, and overall physiological health. Specifically, it delves into the expression and functionality of circRNAs in these species, paying special attention to traits critical to livestock productivity such as milk production, meat quality, muscle development, wool production, immune responses, etc. We also address the current challenges faced in circRNA research, including the need for standardized methodologies and broader studies. By providing insights into the molecular mechanisms regulated by circRNAs, this review underscores their scientific and economic relevance in the livestock industry. The potential of circRNAs to improve animal health management and the quality of animal-derived products aligns with growing consumer concerns for animal welfare and sustainability. Thus, this paper aims to guide future research directions while supporting the development of innovative strategies in livestock management and breeding.