Transcriptomic Analysis Reveals Functional Interaction of mRNA–lncRNA–miRNA in Steroidogenesis and Spermatogenesis of Gynogenetic Japanese Flounder (Paralichthys olivaceus)

Abstract

Teleost fishes exhibit extraordinary diversity, plasticity and adaptability with their sex determination and sexual development, and there is growing evidence that non-coding RNAs (ncRNAs) are emerging as critical regulators of reproduction. Japanese flounder (Paralichthys olivaceus) is an important marine cultured fish that presents significant sexual dimorphism with bigger females, in which gynogenesis has been applied for aquaculture industry. In order to reveal the regulatory mechanisms of sexual development in gynogenetic female and sex-reversed neo-male P. olivaceus, the lncRNA–miRNA–mRNA interactions were investigated using high-throughput sequencing. A total of 6772 differentially expressed mRNAs (DEmRNAs), 2284 DElncRNAs, and 244 DEmiRNAs were obtained between gynogenetic female ovaries and sex-reversed neo-male testes. Genes in the steroid hormone biosynthesis and secretion pathway were enriched and mostly significantly upregulated in neo-male testes. Subsequently, network analysis uncovered high functional specificity for gynogenetic P. olivaceus sperm motility, as co-expressed DEmRNAs were significantly enriched in microtubule and cytoskeleton-related biological processes. Clustered miRNAs were characterized in the P. olivaceus genome with examples of the largest conserved let-7 clusters. The 20 let-7 members are distributed in 11 clusters and may not transcribe together with their neighboring miR-125b, with let-7 repressing cyp11a and miR-125b repressing esr2b, both as key steroidogenesis pathway genes. In summary, this study provides comprehensive insights into the mRNA–miRNA–lncRNA functional crosstalk in teleost sexual development and gametogenesis and will expand our understanding of ncRNA biology in teleost gynogenesis.

The potential regulatory role of the lncRNA-miRNA-mRNA axis in teleost fish

“…Similarly, ncRNAs also showed differential expression between gonads of different sexes in gynogenetic Japanese flounder. A total of 6772 differentially expressed mRNAs (3541 testis-biased and 3231 ovary-biased), 2284 lncRNAs (1870 testis-biased and 414 ovary-biased), and 244 miRNAs (146 testis-biased and 98 ovary-biased) were obtained between gynoenetic female ovaries and sex-reversed neomale testes ( 52 ). Clearly, the numbers of differentially expressed mRNAs and lncRNAs were significantly higher in the testis than in the ovaries, suggesting that ncRNAs function more actively in the neomale testis, especially lncRNAs.…”

“…For example, ovary-biased let-7 binds to 18 lncRNAs and targets dnah1, testis-biased miR-20a interacts with 14 DElncRNAs and targets dnah11, while the novel miRNA-82155_166 can cooperate with 57 lncRNAs to target most large mRNAs. These miRNA-associated regulatory axes involve numerous steroid biogenesis- and sperm motility-related genes and pathways, such as the cytoskeleton, microtubule cytoskeleton, cytoplasmic dynein complex, tubulin and actin binding ( 52 ). These data suggest the regulatory roles of the lncRNA-miRNA-mRNA network in steroidogenesis and sexual spermatogenesis in P. olivaceus .…”

Whole transcriptome sequencing reveals core genes related to spermatogenesis in Bactrian camels

“…LncRNAs act as miRNA sponges and affect the expression of their target genes, leading to the regulation of biological processes, such as influencing testosterone production, cell proliferation, and antioxidant function in Leydig cells ( An et al., 2021 ). A previous study constructed the mRNA–miRNA–lncRNA network related to teleost sexual development and gametogenesis ( Cheng et al., 2022 ). And the study constructed lncRNA-miRNA-mRNA networks in low-dose lead (Pb)-exposed mice testes ( Ma et al., 2022 ).…”

Steroidogenic Effects of Salinity Change on the Hypothalamus–Pituitary–Gonad (HPG) Axis of Male Chinese Sea Bass (Lateolabrax maculatus)

“…The HPG axis plays an essential role in teleost growth and reproduction [6]. The HPG axis is initiated by the secretion of gonadotropin-releasing hormone (GnRH) from neuroendocrine cells in the hypothalamus, which acts on the pituitary to promote folliclestimulating-hormone (FSH) and luteinizing-hormone (LH) release and activate the FSH and LH receptors in the gonads, ultimately leading to the synthesis of steroid hormones [6,7], which are key factors in sex determination and differentiation as well as germ cell development [8,9]. Steroidogenesis is further triggered by steroidogenic acute regulatory protein (Star), mobilizing cholesterol from the outer to the inner mitochondrial membrane [10,11].…”