Small RNA sequencing of cryopreserved semen from single bull revealed altered miRNAs and piRNAs expression between High- and Low-motile sperm populations

E Capra,B Lazzari,I Fojadelli,F Pizzi,A Stella,P Cremonesi,F Turri,T M Gliozzi

doi:10.1186/s12864-016-3394-7

E Capra, B Lazzari + Show 6 more

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https://doi.org/10.1186/s12864-016-3394-7

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Abstract

BackgroundSmall RNAs present in bovine ejaculate can be linked to sperm abnormalities and fertility disorders. At present, quality parameters routinely used in semen evaluation are not fully reliable to predict bull fertility. In order to provide additional quality measurements for cryopreserved semen used for breeding, a method based on deep sequencing of sperm microRNA (miRNA) and Piwi-interacting RNA (piRNA) from individual bulls was developed.To validate our method, two populations of spermatozoa isolated from high and low motile fractions separated by Percoll were sequenced, and their small RNAs content characterized.ResultsSperm cells from frozen thawed semen samples of 4 bulls were successfully separated in two fractions. We identified 83 miRNAs and 79 putative piRNAs clusters that were differentially expressed in both fractions. Gene pathways targeted by 40 known differentially expressed miRNAs were related to apoptosis. Dysregulation of miR-17-5p, miR-26a-5p, miR-486-5p, miR-122-5p, miR-184 and miR-20a-5p was found to target three pathways (PTEN, PI3K/AKT and STAT).ConclusionsSmall RNAs sequencing data obtained from single bulls are consistent with previous findings. Specific miRNAs are differentially represented in low versus high motile sperm, suggesting an alteration of cell functions and increased germ cell apoptosis in the low motile fraction.

Highlights

Small RNAs present in bovine ejaculate can be linked to sperm abnormalities and fertility disorders
Isolation of spermatozoa and evaluation of sperm characteristics Concerning semen quality parameters in the two fractions (HM and Low Motile (LM)) any statistical significant difference was detected among technical replicates
This work firstly provides a comprehensive description of small RNAs isolated from High Motile (HM) and LM fractions from individual bull cryopreserved spermatozoa obtained by Next Generation Sequencing (NGS) sequencing and analysis

Summary

Introduction

Small RNAs present in bovine ejaculate can be linked to sperm abnormalities and fertility disorders. Quality parameters routinely used in semen evaluation are not fully reliable to predict bull fertility. In order to provide additional quality measurements for cryopreserved semen used for breeding, a method based on deep sequencing of sperm microRNA (miRNA) and Piwi-interacting RNA (piRNA) from individual bulls was developed. Two populations of spermatozoa isolated from high and low motile fractions separated by Percoll were sequenced, and their small RNAs content characterized. Infertility is a disorder affecting humans as well as other animals. Infertility is prevalently due to anatomical problems and endocrine disorders causing low sperm counts and poor sperm quality, and in part to genetic disorders [1].

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