Transcriptomic Profiling of Buffalo Spermatozoa Reveals Dysregulation of Functionally Relevant mRNAs in Low-Fertile Bulls

Abstract

Although, it is known that spermatozoa harbor a variety of RNAs that may influence embryonic development, little is understood about sperm transcriptomic differences in relation to fertility, especially in buffaloes. In the present study, we compared the differences in sperm functional attributes and transcriptomic profile between high- and low-fertile buffalo bulls. Sperm membrane and acrosomal integrity were lower (P < 0.05), while protamine deficiency and lipid peroxidation were higher (P < 0.05) in low- compared to high-fertile bulls. Transcriptomic analysis using mRNA microarray technology detected a total of 51,282 transcripts in buffalo spermatozoa, of which 4,050 transcripts were differentially expressed, and 709 transcripts were found to be significantly dysregulated (P < 0.05 and fold change >1) between high- and low-fertile bulls. Majority of the dysregulated transcripts were related to binding activity, transcription, translation, and metabolic processes with primary localization in the cell nucleus, nucleoplasm, and in cytosol. Pathways related to MAPK signaling, ribosome pathway, and oxidative phosphorylation were dysregulated in low-fertile bull spermatozoa. Using bioinformatics analysis, we observed that several genes related to sperm functional attributes were significantly downregulated in low-fertile bull spermatozoa. Validation of the results of microarray analysis was carried out using real-time qPCR expression analysis of selected genes (YBX1, ORAI3, and TFAP2C). The relative expression of these genes followed the same trend in both the techniques. Collectively, this is the first study to report the transcriptomic profile of buffalo spermatozoa and to demonstrate the dysregulation of functionally relevant transcripts in low-fertile bull spermatozoa. The results of the present study open up new avenues for understanding the etiology for poor fertility in buffalo bulls and to identify fertility biomarkers.

Melatonin improves rate of monospermic fertilization and early embryo development in a bovine IVF system

“…Recently, it was shown that a lower level of the microRNA miR-216b in bovine spermatozoa and zygotes was associated with a higher level of K-RAS (a gene of the RAS/MAPK pathway) in two-cell embryos, which increased first cleavage rate and blastocyst cell numbers from bulls with high fertility, while the opposite was for low fertility bulls [ 53 ]. Similarly, transcriptomic profiling of buffalo spermatozoa revealed downregulation of 28 genes associated with MAPK signaling pathway bulls with low fertility compared to those with high fertility [ 54 ]. Thus the enhanced fertilization ability and embryo development observed in our study could hypothetically be linked to this pathway.…”

Cellular and Molecular Insights Into the Etiology of Subfertility/Infertility in Crossbred Bulls (Bos taurus × Bos indicus): A Review

“…Although differences in opinion exist about the transcription and translation activities in spermatozoa, it was observed that paternal RNAs reside in the perinuclear theca of spermatozoa and are transferred during fertilization ( Ostermeier et al, 2005 ). Recent studies profiled sperm RNA and the possible roles in sperm functions and fertilizing ability ( Selvaraju et al, 2017 ; Paul et al, 2020 ; Prakash et al, 2020 ). Increasing evidence indicates that expression of sperm molecules, including mRNAs ( Wang et al, 2019 ; Saraf et al, 2021 ; Selvaraju et al, 2021 ), proteins ( Peddinti et al, 2008 ; Aslam et al, 2015 ), phosphoproteins ( Kumaresan et al, 2012 ), and metabolites ( Saraf et al, 2020 ), were altered in bulls with different fertility ratings.…”

Multi-OMICS and Molecular Biology Perspective in Buffalo Genome

“…This novel technique is now widely used on animals for large-scale gene expression studies involving SNP genotyping, polymorphisms, disease diagnosis, fertility assay etc. [59][60][61][62][63][64].…”

“…Another study demonstrated transcriptional analysis of potential buffalo genes that are associated with buffalo oocyte maturation using the microarray technology [62]. Very recently, microarray technology had also been used to analyze the transcriptomic profile of buffalo spermatozoa that report the alteration of functionally relevant transcripts in low-fertile bull spermatozoa [63]. Thus, microarray technology can allow animal geneticists and breeders to select animals based on multiple traits and hopefully can revolutionize the buffalo production and breeding industry.…”