Transcriptome-wide m6A profiling reveals mRNA post-transcriptional modification of boar sperm during cryopreservation

Abstract

Background Cryopreservation induces transcriptomic and epigenetic modifications that strongly impairs sperm quality and function, and thus decrease reproductive performance. N6-methyladenosine (m6A) RNA methylation varies in response to stress and has been implicated in multiple important biological processes, including post-transcriptional fate of mRNA, metabolism, and apoptosis. This study aimed to explore whether cryopreservation induces m6A modification of mRNAs associated with sperm energy metabolism, cryoinjuries, and freezability. Results The mRNA and protein expression of m6A modification enzymes were significantly dysregulated in sperm after cryopreservation. Furthermore, m6A peaks were mainly enriched in coding regions and near stop codons with classical RRACH motifs. The mRNAs containing highly methylated m6A peaks (fts vs. fs) were significantly associated with metabolism and gene expression, while the genes with less methylated m6A peaks were primarily involved in processes regulating RNA metabolism and transcription. Furthermore, the joint analysis of DMMGs and differentially expressed genes indicated that both of these play a vital role in sperm energy metabolism and apoptosis. Conclusions Our study is the first to reveal the dynamic m6A modification of mRNAs in boar sperm during cryopreservation. These epigenetic modifications may affect mRNA expression and are closely related to sperm motility, apoptosis, and metabolism, which will provide novel insights into understanding of the cryoinjuries or freezability of boar sperm during cryopreservation.

Gravitational folding of surface tension regions originates bio quantum path duality that quantizes Newtonian rigid inertia into parameter trigonometric inversion topological bio inertia

“…Before fertilization, both sperm cells and ova need two-stage meiosis to get haploid cells. There are a lot of factors that impact the process [10][11][12] , finally, the selection of a successful candidate should be the one with the highest percentage of physical trigonometric curves which inversion superposed by nuDNA and mtDNA from the long journey of spermatozoa with mitochondria integrated into their middle pieces. The one with a higher percentage of trigonometric curves can acquire more gravitational binding inversion energy in the journey.…”

Cryopreservation of Gametes and Embryos and Their Molecular Changes

“…Bax upregulation and Bcl2 downregulation were related to enhanced apoptosis in cryopreserved mice sperm [ 110 ]. In boar, cryopreservation increased mRNA levels of FTO and decreased METTL3 , METTL14 , ALKBH5 , and YTHDF2 , which are transcripts involved in the posttranscriptional mRNA modification mediated by N6-methyladenosine [ 127 ]. In frozen–thawed bull sperm, the RPL31 gene was upregulated [ 128 ].…”

Expression of TXNRD1, HSPA4L and ATP1B1 Genes Associated with the Freezability of Boar Sperm

“…It has been suggested that sperm RNAs are transcriptionally inactive; however, studies have shown that sperm transport specific functional RNAs into the oocyte at the time of fertilization, and these RNAs could contribute to early embryonic development [ 6 , 7 , 8 , 9 ]. Studies have demonstrated that cryopreservation has varying effects on the profiles of sperm mRNA transcripts, which could be used as markers for sperm functions [ 8 , 10 , 11 , 12 , 13 , 14 ]. Expression of PRM1 (Protamine 1) and PRM2 (Protamine 2), suggested as potential fertility markers, is significantly reduced in frozen-thawed (FT) human sperm [ 10 ], and significant changes in the mRNA expression and protein levels of epigenetic-related genes have been detected in FT boar sperm [ 11 , 14 ].…”

“…Studies have demonstrated that cryopreservation has varying effects on the profiles of sperm mRNA transcripts, which could be used as markers for sperm functions [ 8 , 10 , 11 , 12 , 13 , 14 ]. Expression of PRM1 (Protamine 1) and PRM2 (Protamine 2), suggested as potential fertility markers, is significantly reduced in frozen-thawed (FT) human sperm [ 10 ], and significant changes in the mRNA expression and protein levels of epigenetic-related genes have been detected in FT boar sperm [ 11 , 14 ]. Evidence has shown that transcriptome modifications in FT bull sperm are associated with reduced fertility [ 12 ], and an abundance of differentially expressed (DE) genes that are highly overexpressed in FT bull sperm with poor motility [ 13 ].…”