tRNA^(Glu)-derived fragments from embryonic extracellular vesicles modulate bovine embryo hatching

Transfer RNA-derived small RNAs(tsRNAs)have been shown to be involved in early embryo development and repression of endogenous retroelements in embryos and stem cells.However,it is unknown whether tsRNAs also regulate embryo hatching.In this study,we mined the sequencing data of a previous experiment in which we demonstrated that the microRNA(miRNA)cargo of preimplantation embryonic extracellular vesicles(EVs)influences embryo development.We thus profiled the tsRNA cargo of EVs secreted by blastocysts and non-blastocysts.The majority of tsRNAs was identified as tRNA halves originating from the 5'ends of tRNAs.Among the 148 differentially expressed tsRNAs,the 19 nt tRNA fragment(tRF)tDR-14:32-Glu-CTC-1 was found to be significantly up-regulated in EVs derived from non-blastocysts.RT-qPCR assays confirmed its significant up-regulation in non-blastocyst embryos and their conditioned medium compared to the blastocyst group(P<0.05).Inhibition of tDR-14:32-Glu-CTC-1 by supplementing antagomirs to the conditioned medium improved embryo hatching(P<0.05).Transcriptomic analysis of embryos treated with tDR-14:32-Glu-CTC-1 antagomirs further showed differential expression of genes that are associated with embryo hatching and implantation.In summary,tDR-14:32-Glu-CTC-1 is up-regulated in non-blastocyst embryos and their secretions,and inhibition of tDR-14:32-Glu-CTC-1 promotes embryo hatching,while influencing embryo implantation-related genes and pathways.These results indicate that embryonic EVs containing specific tRFs may regulate preimplantation embryo development.

Mycotoxin binder improves growth rate in piglets associated with reduction of toll-like receptor-4 and increase of tight junction protein gene expression in gut mucosa

Background: Deoxynivalenol(DON) is a mycotoxin produced by Fusarium species in the field, commonly found in cereal grains, which negatively affects performances and health of animals. Mycotoxin binders are supposed to reduce the toxicity of mycotoxins.Method: The effect of a mycotoxin binder(containing acid-activated bentonite, clinoptilolite, yeast cell walls and organic acids) on growth performance and gut health was studied. Hundred and twenty weaning piglets were allocated to 4 treatments, with 5 pens of 6 piglets each, arranged in a 2 × 2 factorial design: control diet; control diet with 1 kg/t binder; control diet with DON; and control diet with DON and 1 kg/t binder. From d0–14,the diet of DON-challenged groups was artificially contaminated with a mixture of DON(2.6 mg/kg), 3-acetyldeoxynivalenol(0.1 mg/kg) and 15-acetyl-deoxynivalenol(0.3 mg/kg), after which the total contamination level was reduced to 1 mg/kg, until d37. On d14, one pig from each pen was euthanized and distal small intestinal mucosa samples were collected for the assessment of intestinal permeability, and gene expression of tight junction proteins, toll-like receptor 4, inflammatory cytokines and intestinal alkaline phosphatase.Results: After 37 d, there were no differences in growth performance between control and DON-challenged groups(P > 0.05). Nevertheless, groups that received diets with binder had a significantly higher average daily gain(ADG) and average daily feed intake(ADFI) for the first 14 d as well as for the whole period, compared to groups without binder(P ≤ 0.05). Groups with binder in the diet also exhibited lower expression of toll-like receptor 4 in distal small intestinal mucosa at d14, compared to groups without binder(P ≤ 0.05). Interestingly, comparing the two DON treatments, piglets fed DON and binder had significantly higher ADFI and ADG compared to those with only DON for the first 14-d(P ≤ 0.05). Addition of binder to DON contaminated diets, also down-regulated the gene expression of toll-like receptor 4(P ≤ 0.05) and increased m RNA level zona occludens 1(P ≤ 0.10) as compared to DON.Conclusions: The present data provide evidence that the binder improves growth rate in piglets associated with reduction of toll-like receptor-4 and increase of tight junction protein gene expression. However, the current study does not allow to assess whether the effects of the binder are mediated by alterations in the toxicokinetics of the mycotoxin.