Localisation and in silico based functional analysis of miR-202 in bull testis

Bull fertility is pivotal to the prosperity of the cattle industry worldwide. miR‐202 has been shown to be gonad specific and to have key roles in gonad function in different species. To further understand the involvement of miR‐202 in bull reproduction, this study aimed to establish its localization in bovine testicular tissue and to identify putative biological functions using bioinformatics approaches. We assessed the miR‐202 expression in paraffin‐embedded tissue samples collected form an abattoir using in situ hybridization. miR‐202 was present in Sertoli cells and in germ cells at different stages of development. Using available databases, a total of 466 predicted gene targets of miR‐202 were identified. Functional annotation revealed that miR‐202 target genes were mainly associated with protein modification and phosphorylation processes as well as longevity regulating pathway. Moreover, genes in the longevity regulating pathway mapped to PI3K/Akt/mTOR pathway which is involved in promoting proliferation of testicular cells and spermatogenesis. These findings suggest that miR‐202 plays important roles in regulating proliferation and viability of testicular cells including somatic and germ cells

Associations between testicular development and fetal size in the pig

BACKGROUND: Impaired reproductive performance is the largest contributing factor for the removal of boars from commercial systems. Intrauterine growth restricted piglets represent 25% of the total number of piglets born and have impaired reproductive performance. This study aimed to improve the understanding of temporal changes in testicular gene expression during testes development in fetuses of different size. The lightest and closest to mean litter weight (CTMLW) male Large White × Landrace littermates were collected at gestational days (GD) 45, 60 and 90 (n = 5–6 litters/GD). RESULTS: Testes weight and testes weight as a percentage of fetal weight were not associated with fetal size at GD60 or 90. Fetal plasma testosterone was not associated with fetal size at GD90. There was no association between fetal size and seminiferous tubule area and number, number of germ or Sertoli cells per tubule. The lightest fetuses tended to have wider seminiferous tubules compared to the CTMLW fetuses at GD90 (P = 0.077). The testicular expression of KI67 (P ≤ 0.01) and BAX:BCL2 ratio (P = 0.058) mRNAs decreased as gestation progressed. Greater SPP1 mRNA expression was observed at GD60 when compared with GD45 and 90 (P ≤ 0.05). Lower expression of DMRT1 and SPP1 (P < 0.01) mRNAs was observed in testes associated with the lightest fetuses compared to the CTMLW fetuses at GD90. CONCLUSIONS: These findings provide novel insights into the expression profiles of genes associated with testicular development and function. Further, these data suggest that programming of reproductive potential in IUGR boars occurs late in gestation, providing a platform for further mechanistic investigation. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s40104-022-00678-3

Prospects and Challenges of Induced Pluripotent Stem Cells in Equine Health

Pluripotent stem cells (PSCs) hold, through the capacity to differentiate into virtually all body cell types, unprecedented promise for human and animal medicine. PSCs are naturally found in the early embryo, and in rodents and humans they can be robustly harvested and grown in culture in the form of embryonic stem cells (ESCs), however the availability of ESCs from horses is limited. ES-like cells named induced pluripotent stem cells (iPSCs) can be derived in vitro by transcription factor-mediated reprogramming of adult cells. As such, iPSCs can be generated in a patient-specific manner providing unmatched potential for tissue transplantation and in vitro disease modelling. In humans, clinical trials using iPSC-derived cells are already taking place and the use of in vitro iPSC models has identified novel mechanisms of disease and therapeutic targets. Although to a more limited extent, iPSCs have also been generated from horses, a species in which, after humans, these cells are likely to hold the greatest potential in regenerative medicine. Before a clinical use can be envisioned, however, significant challenges will need to be addressed in relation to the robust derivation, long-term culture, differentiation and clinical safety of equine iPSCs. Towards this objective, recent studies have reported significant improvement in culture conditions and the successful derivation for the first time of functional cell types from equine iPSCs. Given the wide range of exciting applications they could have, it is hoped future research will make the biomedical promise of iPSCs a reality not only for humans but also horses

KLB dysregulation mediates disrupted muscle development in intrauterine growth restriction

ABSTRACT: Intrauterine growth restriction (IUGR) is a leading cause of neonatal morbidity and mortality in humans and domestic animals. Developmental adaptations of skeletal muscle in IUGR lead to increased risk of premature muscle loss and metabolic disease in later life. Here, we identified β‐Klotho (KLB), a fibroblast growth factor 21 (FGF21) co‐receptor, as a novel regulator of muscle development in IUGR. Using the pig as a naturally‐occurring disease model, we performed transcriptome‐wide profiling of fetal muscle (day 90 of pregnancy) from IUGR and normal‐weight (NW) littermates. We found that, alongside large‐scale transcriptional changes comprising multiple developmental, tissue injury and metabolic gene pathways, KLB was increased in IUGR muscle. Moreover, FGF21 concentrations were increased in plasma in IUGR fetuses. Using cultures of fetal muscle progenitor cells (MPCs), we showed reduced myogenic capacity of IUGR compared to NW muscle in vitro, as evidenced by differences in fusion indices and myogenic transcript levels, as well as mechanistic target of rapamycin (mTOR) activity. Moreover, transfection of MPCs with KLB small interfering RNA promoted myogenesis and mTOR activation, whereas treatment with FGF21 had opposite and dose‐dependent effects in porcine and also in human fetal MPCs. In conclusion, our results identify KLB as a novel and potentially critical mediator of impaired muscle development in IUGR, through conserved mechanisms in pigs and humans. Our data shed new light onto the pathogenesis of IUGR, a significant cause of lifelong ill‐health in humans and animals. KEY POINTS: Intrauterine growth restriction (IUGR) is associated with large‐scale transcriptional changes in developmental, tissue injury and metabolic gene pathways in fetal skeletal muscle. Levels of the fibroblast growth factor 21 (FGF21) co‐receptor, β‐Klotho (KLB) are increased in IUGR fetal muscle, and FGF21 concentrations are increased in IUGR fetal plasma. KLB mediates a reduction in muscle development through inhibition of mechanistic target of rapamycin signalling. These effects of KLB on muscle cells are conserved in pig and human, suggesting a vital role of this protein in the regulation of muscle development and function in mammals