Analysis of Expression Profiles of CircRNA and MiRNA in Oviduct during the Follicular and Luteal Phases of Sheep with Two Fecundity (FecB Gene) Genotypes

Abstract

CircRNA and miRNA, as classes of non-coding RNA, have been found to play pivotal roles in sheep reproduction. There are many reports of circRNA and miRNA in the ovary and uterus, but few in the oviduct. In this study, RNA-Seq was performed to analyze the expression profile of circRNA and miRNA in the oviduct during the follicular phase and luteal phase of sheep with FecBBB and FecB++ genotypes. The results showed that a total of 3223 circRNAs and 148 miRNAs were identified. A total of 15 DE circRNAs and 40 DE miRNAs were found in the comparison between the follicular phase and luteal phase, and 1 DE circRNA and 18 DE miRNAs were found in the comparison between the FecBBB genotype and FecB++ genotype. GO and KEGG analyses showed that the host genes of DE circRNAs were mainly enriched in the Rap1 signaling pathway, PI3K–Akt signaling pathway and neuroactive ligand–receptor interactions. Novel_circ_0004065, novel_circ_0005109, novel_circ_0012086, novel_circ_0014274 and novel_circ_0001794 were found to be possibly involved in the oviductal reproduction process. GO and KEGG analyses showed that the target genes of DE miRNAs were mainly enriched in insulin secretion, the cAMP signaling pathway, the cGMP–PKG signaling pathway, the Rap1 signaling pathway and the TGF-β signaling pathway, and the target genes LPAR1, LPAR2, FGF18, TACR3, BMP6, SMAD4, INHBB, SKP1 and TGFBR2 were found to be associated with the reproductive process. Miranda software was used to identify 27 miRNAs that may bind to 13 DE circRNAs, including miR-22-3p (target to novel_circ_0004065), miR-127, miR-136 (target to novel_circ_0000417), miR-27a (target to novel_circ_0014274) and oar-miR-181a (target to novel_circ_ 0017815). The results of this study will help to elucidate the regulatory mechanisms of circRNAs and miRNAs in sheep reproduction. Our study, although not establishing direct causal relationships of the circRNA and miRNA changes, enriches the sheep circRNA and miRNA database and provides a basis for further studies on sheep reproduction.

Genome wide identification and characterization of fertility associated novel CircRNAs as ceRNA reveal their regulatory roles in sheep fecundity

“…44 circRNAs were differentially expressed and majority of enriched GO terms of DECs host genes were related to cell proliferation and reproductive process and KEGG enrichment analysis enriched in cell adhesion molecules, phagosome, PI3K-Akt signaling pathway, neuroactive ligand-receptor interaction, glutathione metabolism, metabolism of xenobiotics by cytochrome P450, MAPK, axon guidance, valine, leucine and isoleucine degradation, and endocytosis pathways. A similar phenomenon was observed in other studies [ 27 , 28 , 32 ]. Metabolic changes reported during transition period from ovulation to the estrous and biomolecules including vitamins, amino acids, lipid, benzoic acid, carbohydrates and other intermediate and secondary metabolites are at their highest levels at the time of ovulation [ 27 , 69 , 70 ].…”

“…In sheep uterus study, 147 and 364 circRNAs out of 32,687 were differentially expressed in polytocous and monotocous groups in the follicular phase and luteal phases and DECs host genes significantly enriched with estrogen signaling pathway, oxytocin signaling pathway [ 27 ]. While, in the comparative study between the follicular phase/luteal phase of sheep, 15 DECs out of 3223 were predicted and DECs host genes were enriched in the Rap1 signaling pathway, PI3K–Akt signaling pathway and neuroactive ligand–receptor interactions [ 28 ]. In this study, we found 9,878 new circRNAs with a total length of 23522667nt and an average length of 2381.32nt respectively.…”

“…Several circRNAs have been identified via high-throughput RNA sequencing in various tissues, such as the hypothalamus [ 25 ], pituitary [ 26 ], uterus [ 27 ], and oviduct [ 28 ]. Many recent studies have shown that circRNAs may have unique and important functions during embryonic development, and their expression is the most abundant and complex in the cerebral cortex on the 60th day of pregnancy [ 29 ].…”

“…Another example of novel_circ_0000417 that competitively bind with miR-136 and promote the apoptotic process in human granulosa cells [ 30 ]. In ovine oviduct, novel_circ_0017815 determined as a molecular sponge for oar-miR-181a and regulate the estradiol synthesis and follicular apoptosis [ 28 ]. ceRNA study on porcine follicles have highlighted the role of circINHA as a sponge for miR-10a-5p, thus upregulates the expression of connective tissue growth factor (CTGF) and prevent granulosa cells from apoptosis [ 31 ].…”

Transcriptomics and Metabolomics Analysis of the Ovaries of High and Low Egg Production Chickens

“…INHBB (inhibin beta B subunit) is a glycoprotein hormone that belongs to the transforming growth factor-β superfamily and inhibits follicle-stimulating hormone (FSH) production and secretion [ 27 ]. Knockdown of INHBB increases apoptosis and inhibits steroidogenesis in mouse granulosa cells [ 28 ], and the gene was also found to be closely associated with reproductive processes in sheep [ 29 ]. High expression of INHBB transcripts in the ovaries of WL hens may increase the apoptosis of granulosa cells, inhibit hormone production, and lead to lower egg production.…”