The Novel Competing Endogenous Long Noncoding RNA SM2 Regulates Gonadotropin Secretion in the Hu Sheep Anterior Pituitary by Targeting the Oar-miR-16b/TGF-β/SMAD2 Signaling Pathway

Role of microRNAs in pituitary gonadotrope cells

The gonadotrope cells within the pituitary control vital processes of reproduction by producing follicle stimulating hormone (FSH) and luteinizing hormone (LH). Both external stimuli and internal regulatory factors contribute to the regulation of gonadotrope development and function. In recent years, growing evidences indicate that microRNAs (miRNAs), which regulate gene expression post-transcriptionally, play critical roles in multiple processes of gonadotrope development and function, including the syntheses of α or β subunits of FSH and LH, the secretion of LH, the regulation of GnRH signaling, and the maintenance of gonadotrope cell kinetics. Here, we review recent advances of miRNAs' expression, functions and mechanisms approached by using miRNA knockout mouse models, in silico analysis and the in vitro cultures of primary pituitary cells and gonadotrope-derived cell lines. By summarizing and discussing different roles of miRNAs in gonadotropes, this minireview helps to gain insights into the complex molecular network in gonadotropes and reproduction.

Key mRNAs and lncRNAs of pituitary that affect the reproduction of FecB + + small tail han sheep

BACKGROUND

The pituitary directly regulates the reproductive process through follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Transcriptomic research on the pituitaries of ewes with different FecB (fecundity Booroola) genotypes has shown that some key genes and lncRNAs play an important role in pituitary function and sheep fecundity. Our previous study found that ewes with FecB + + genotypes (without FecB mutation) still had individuals with more than one offspring per birth. It is hoped to analyze this phenomenon from the perspective of the pituitary transcriptome.

RESULTS

The 12 Small Tail Han Sheep were equally divided into polytocous sheep in the follicular phase (PF), polytocous sheep in the luteal phase (PL), monotocous sheep in the follicular phase (MF), and monotocous sheep in the luteal phase (ML). Pituitary tissues were collected after estrus synchronous treatment for transcriptomic analysis. A total of 384 differentially expressed genes (DEGs) (182 in PF vs. MF and 202 in PL vs. ML) and 844 differentially expressed lncRNAs (DELs) (427 in PF vs. MF and 417 in PL vs. ML) were obtained from the polytocous-monotocous comparison groups in the two phases. Functional enrichment analysis showed that the DEGs in the two phases were enriched in signaling pathways known to play an important role in sheep fecundity, such as calcium ion binding and cAMP signaling pathways. A total of 1322 target relationship pairs (551 pairs in PF vs. MF and 771 pairs in PL vs. ML) were obtained for the target genes prediction of DELs, of which 29 DEL-DEG target relationship pairs (nine pairs in PF vs. MF and twenty pairs in PL vs. ML). In addition, the competing endogenous RNA (ceRNA) networks were constructed to explore the regulatory relationships of DEGs, and some important regulatory relationship pairs were obtained.

CONCLUSION

According to the analysis results, we hypothesized that the pituitary first receives steroid hormone signals from the ovary and uterus and that VAV3 (Vav Guanine Nucleotide Exchange Factor 3), GABRG1 (Gamma-Aminobutyric Acid A Receptor, Gamma 1), and FNDC1 (Fibronectin Type III Domain Containing 1) played an important role in this process. Subsequently, the reproductive process was regulated by gonadotropins, and IGFBP1 (Insulin-like Growth Factor Binding Protein 1) was directly involved in this process, ultimately affecting litter size. In addition, TGIF1 (Transforming Growth Factor-Beta-Induced Factor 1) and TMEFF2 (Transmembrane Protein With EGF Like And Two Follistatin Like Domains 2) compensated for the effect of the FecB mutation and function by acting on TGF-β/SMAD signaling pathway, an important pathway for sheep reproduction. These results provided a reference for understanding the mechanism of multiple births in Small Tail Han Sheep without FecB mutation.

LncRNA12097.1 contributes to endometrial cell growth by enhancing YES1 activating β-catenin via sponging miR-145-5p

Despite previous investigations elucidating the regulatory mechanisms of long non-coding RNAs (lncRNAs) in endometrial function and reproductive disorders, the precise pathways through which lncRNAs impact endometrial functions and fertility remain unclear. In this study, we performed an expression profile analysis of lncRNAs in the endometrial tissue of Hu sheep with different prolificacy, identifying 13,707 lncRNAs. We discovered a bidirectional lncRNA, designated lncRNA12097.1, exhibiting significant up-regulation exclusively in the endometrium of Hu sheep with high fecundity. Functional analyses revealed lncRNA12097.1 significantly enhanced proliferation and cell cycle progression in both endometrial epithelial cell (EEC) and stromal cells (ESC), while inhibiting apoptosis in these cell types. Mechanistically, we demonstrated a directly interaction between lncRNA12097.1 and miR-145-5p, with YES proto-oncogene 1 (YES1) being identified as a validated target of miR-145-5p. Interference with lncRNA12097.1 resulted in suppressed cell growth through down-regulation of YES1 expression, which could be rescued by miR-145-5p. Furthermore, lncRNA12097.1 functions as a competitive endogenous RNA (ceRNA) for miR-145-5p in ESCs, sequestering miR-145-5p and preventing its binding to the 3'UTR of YES1 mRNA. This interaction led to increased expression of YES1 and subsequent activation of downstream β-catenin signaling, thereby promoting ESC growth in Hu sheep. These findings provide novel molecular insights into the mechanisms underlying prolificacy in sheep.

Transcriptome analysis reveals pituitary lncRNA, circRNA and mRNA affecting fertility in high- and low-yielding goats

The pituitary gland serves as the central endocrine regulator of growth, reproduction, and metabolism and plays a crucial role in the reproductive process of female animals. Transcriptome analysis was conducted using pituitary gland samples from Leizhou goats with varying levels of fecundity to investigate the effects of long noncoding RNA (lncRNA), circular RNA (circRNA), and mRNA regulation on pituitary hormone secretion and its association with goat fecundity. The analysis aimed to identify lncRNAs, circRNAs, and mRNAs that influence the fertility of Leizhou goats. GO and KEGG enrichment analyses were performed on differentially expressed lncRNAs, circRNAs, and mRNAs and revealed considerable enrichment in pathways, such as regulation of hormone secretion, germ cell development, and gonadotropin-releasing hormone secretion. The pituitary lncRNAs (ENSCHIT00000010293, ENSCHIT00000010304, ENSCHIT00000010306, ENSCHIT00000010290, ENSCHIT00000010298, ENSCHIT00000006769, ENSCHIT00000006767, ENSCHIT00000006921, and ENSCHIT00000001330) and circRNAs (chicirc_029285, chicirc_026618, chicirc_129655, chicirc_018248, chicirc_122554, chicirc_087101, and chicirc_078945) identified as differentially expressed regulated hormone secretion in the pituitary through their respective host genes. Additionally, differential mRNAs (GABBR2, SYCP1, HNF4A, CBLN1, and CDKN1A) influenced goat fecundity by affecting hormone secretion in the pituitary gland. These findings contribute to the understanding of the molecular mechanisms underlying pituitary regulation of fecundity in Leizhou goats.

Comparative Transcriptomics Identify Key Pituitary Circular RNAs That Participate in Sheep (Ovis aries) Reproduction

CircRNAs have been found to play key roles in many biological processes and have diverse biological functions. There have been studies on circRNAs in sheep pituitary, and some important circRNAs have been found. But there are still few studies on circRNAs in sheep pituitary with different fecundity. In this study, we obtained the circRNAs expression profiles in the pituitary of FecB ++ genotype Small Tail Han sheep with different fecundity and estrous phases. A total of 34,878 circRNAs were identified in 12 pituitary samples, 300 differentially expressed circRNAs (DE circRNAs) (down: 104; up: 196) were identified in polytocous sheep in the follicular phase (PF) and monotocous sheep in the follicular phase (MF) (PF vs. MF), and 347 DE circRNAs (down: 162; up: 185) were identified in polytocous sheep in the luteal phase (PL) and monotocous sheep in the luteal phase (ML) (PL vs. ML). Cortisol synthesis and secretion pathway (follicular phase) and estrogen signaling pathway (luteal phase) were obtained by functional enrichment analysis of circRNAs source genes. Competing endogenous RNA (ceRNA) network analysis of key DE circRNAs revealed that oar-circ-0022776 (source gene ITPR2, follicular phase) targeted oar-miR-432, oar-circ-0009003 (source gene ITPR1, luteal phase) and oar-circ-0003113 (source gene PLCB1, luteal phase) targeted oar-miR-370-3p. We also explored the coding ability of DE circRNAs. In conclusion, our study shows that changes in the pituitary circRNAs may be related to the response of the pituitary to steroid hormones and regulate the reproductive process of sheep by affecting the pituitary function. Results of this study provide some new information for understanding the functions of circRNAs and the fecundity of FecB ++ genotype sheep.

EZH2 Gene Knockdown Inhibits Sheep Pituitary Cell Proliferation via Downregulating the AKT/ERK Signaling Pathway

Pituitary gonadotropins perform essential functions in mammalian reproduction by stimulating gametogenesis and steroidogenesis in the ovaries and testicles. EZH2 is a histone methyltransferase that inhibits proliferation and aggravates apoptosis in stem cells subjected to pathological stimuli. However, the expression and molecular mechanisms of EZH2 in pituitary cells in vitro have not been extensively studied. In this study, the relative abundances of EZH2 mRNA (p < 0.01) and protein (p < 0.05) expression were larger in the pituitary cells of Hu sheep with relatively greater fecundity (GF) compared to those with lesser fecundity (LF). Loss-of-function examinations demonstrated that EZH2 gene knockdown led to an earlier induction of apoptosis in sheep pituitary cells (PCs). The relative abundance of CASP3, CASP9, and BAX was increased (p < 0.01), while BCL2's abundance was less decreased (p < 0.01) in PCs where there was EZH2 gene knockdown. Additionally, cell proliferation (p < 0.01) and viability (p < 0.01) were decreased in EZH2-knockdown sheep PCs, and the cell cycle was blocked compared to a negative control (NC). Notably, EZH2 gene knockdown led to reduced abundances of gonadotropin subunit gene transcripts (FSHβ, p < 0.05) and reduced FSH release (p < 0.01) from PCs. EZH2 gene knockdown led to reduced phosphorylation of AKT, ERK, and mTOR (p < 0.01). The results suggest that EZH2 regulates pituitary cell proliferation, apoptosis, and FSH secretion through modulation of the AKT/ERK signaling pathway, providing a foundation for further study of pituitary cell functions.

Oviduct Transcriptomic Reveals the Regulation of mRNAs and lncRNAs Related to Goat Prolificacy in the Luteal Phase

Simple Summary

The kidding number is an important reproductive trait in domestic goats. The oviduct, as one of the most major organs, is directly involved in the reproductive process, providing nutrition and a location for early embryonic development. The current study provides genome-wide expression profiles of mRNA and long noncoding RNAs (lncRNAs) expression in Yunshang black goat, a new breed of meat goat bred in China with a high kidding number. During the luteal phases, oviduct mRNAs and lncRNAs associated with high- and low-fecundity Yunshang black goats were identified, and their potential biological functions were predicted using GO, KEGG, and GSEA enrichment analysis. These findings shed light on the oviduct-based prolificacy mechanism in goats.

Abstract

The oviduct is associated with embryo development and transportation and regulates the pregnancy success of mammals. Previous studies have indicated a molecular mechanism of lncRNAs in gene regulation and reproduction. However, little is known about the function of lncRNAs in the oviduct in modulating goat kidding numbers. Therefore, we combined RNA sequencing (RNA-seq) to map the expression profiles of the oviduct at the luteal phase from high- and low-fecundity goats. The results showed that 2023 differentially expressed mRNAs (DEGs) and 377 differentially expressed lncRNAs (DELs) transcripts were screened, and 2109 regulated lncRNA-mRNA pairs were identified. Subsequently, the genes related to reproduction (IGF1, FGFRL1, and CREB1) and those associated with embryonic development and maturation (DHX34, LHX6) were identified. KEGG analysis of the DEGs revealed that the GnRH- and prolactin-signaling pathways, progesterone-mediated oocyte maturation, and oocyte meiosis were related to reproduction. GSEA and KEGG analyses of the target genes of DELs demonstrated that several biological processes and pathways might interact with oviduct functions and the prolificacy of goats. Furthermore, the co-expression network analysis showed that XLOC_029185, XLOC_040647, and XLOC_090025 were the cis-regulatory elements of the DEGs MUC1, PPP1R9A, and ALDOB, respectively; these factors might be associated with the success of pregnancy and glucolipid metabolism. In addition, the GATA4, LAMA2, SLC39A5, and S100G were trans-regulated by lncRNAs, predominantly mediating oviductal transport to the embryo and energy metabolism. Our findings could pave the way for a better understanding of the roles of mRNAs and lncRNAs in fecundity-related oviduct function in goats.