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Insulin-like growth factor-binding protein-5 (IGFBP-5) has recently been shown to alter the reproductive capacity by regulating insulin-like growth factor (IGF) bioavailability or IGF-independent effects. The present study aimed to investigate the effect and mechanism of IGFBP-5 on the onset of puberty in female rats. Immunofluorescence and real-time quantitative PCR were used to determine the expression and location of IGFBP-5 mRNA and protein distribution in the infant's hypothalamus-pituitary-ovary (HPO) axis prepuberty, peripuberty, puberty and adult female rats. Prepubertal rats with IGFBP-5 intracerebroventricular (ICV) were injected to determine the puberty-related genes expression and the concentrations of reproductive hormones. Primary hypothalamic cells were treated with IGFBP-5 to determine the expression of puberty-related genes and the Akt and mTOR proteins. Results showed that Igfbp-5 mRNA and protein were present on the HPO axis. The addition of IGFBP-5 to primary hypothalamic cells inhibited the expression of Gnrh and Igf-1 mRNAs (P < 0.05) and increased the expression of AKT and mTOR protein (P < 0.01). IGFBP-5 ICV-injection delayed the onset of puberty, reduced Gnrh, Igf-1, and Fshβ mRNAs, and decreased the concentrations of E2, P4, FSH,serum LH levels and the ovaries weight (P < 0.05). More corpus luteum and fewer primary follicles were found after IGFBP-5 injection (P < 0.05)., (© 2022. The Author(s).)

This study investigated how lncRNA Meg3 affects the onset of puberty in female rats. We determined Meg3 expression in the hypothalamus-pituitary-ovary axis of female rats at the infancy, prepubertal, pubertal, and adult life stages, using quantitative reverse transcription polymerase chain reaction (qRT-PCR). We also assessed the effects of Meg3 knockdown on the expression levels of puberty-related genes and Wnt/β-catenin proteins in the hypothalamus, time of puberty onset, levels of reproductive genes and hormones, and ovarian morphology in female rats. Meg3 expression in the ovary varied significantly between prepuberty and puberty (P < 0.01). Meg3 knockdown decreased the expression of Gnrh , and Kiss1 mRNA (P < 0.05) and increased the expression of Wnt (P < 0.01) and β-catenin proteins (P < 0.05) in the hypothalamic cells. Onset of puberty in Meg3 knockdown rats was delayed compared to the control group (P < 0.05). Meg3 knockdown decreased Gnrh mRNA levels (P < 0.05) and increased Rfrp- 3 mRNA levels (P < 0.05) in the hypothalamus. The serum concentrations of progesterone (P 4) and estradiol (E 2) of Meg3 knockdown rats were lower than those in the control animals (P < 0.05). Higher longitudinal diameter and ovary weight were found in Meg3 knockdown rats (P < 0.05). These findings suggest that Meg3 regulates the expression of Gnrh , Kiss- 1 mRNA and Wnt/β-catenin proteins in the hypothalamic cells, and Gnrh , Rfrp- 3 mRNA of the hypothalamus and the serum concentration of P 4 and E 2 , and its knockdown delays the onset of puberty in female rats. • Meg3 was expressed in the hypothalamus, pituitary, and ovary of female rats at different developmental stages. • Vaginal opening in Meg3 knockdown rats was delayed. • Knockdown Meg3 delayed the onset of puberty in rats and the concentration of reproductive hormone in serum. • In vitro, knockdown of Meg3 affected the transcription level of Kiss1 mRNA and Wnt/β-catenin proteins in hypothalamic cells. • In vivo, knockdown of Meg3 affected the transcription level of Gnrh and Rfrp- 3 mRNA in the hypothalamus. [ABSTRACT FROM AUTHOR]

Background: Changes in the abundance of ovarian proteins play a key role in the regulation of reproduction. However, to date, no studies have investigated such changes in pubescent goats. Herein we applied isobaric tags for relative and absolute quantitation (iTRAQ) and liquid chromatography–tandem mass spectrometry to analyze the expression levels of ovarian proteins in pre-pubertal (n = 3) and pubertal (n = 3) goats. Results: Overall, 7,550 proteins were recognized; 301 (176 up- and 125 downregulated) were identified as differentially abundant proteins (DAPs). Five DAPs were randomly selected for expression level validation by Western blotting; the results of Western blotting and iTRAQ analysis were consistent. Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis indicated that DAPs were enriched in olfactory transduction, glutathione metabolism, and calcium signaling pathways. Besides, gene ontology functional enrichment analysis revealed that several DAPs enriched in biological processes were associated with cellular process, biological regulation, metabolic process, and response to stimulus. Protein–protein interaction network showed that proteins interacting with CDK1, HSPA1A, and UCK2 were the most abundant. Conclusions: We identified 301 DAPs, which were enriched in olfactory transduction, glutathione metabolism, and calcium signaling pathways, suggesting the involvement of these processes in the onset of puberty. Further studies are warranted to more comprehensively explore the function of the identified DAPs and aforementioned signaling pathways to gain novel, deeper insights into the mechanisms underlying the onset of puberty. [ABSTRACT FROM AUTHOR]

Simple Summary: This study evaluated the effect of γ-aminobutyric acid transaminase (GABA-T) on reproduction in female rats. Our results showed that GABA-T expressed in the reproductive axis of female rats at different developmental stages, and inhibiting GABA-T affected Rfrp-3, Gnrh and Kiss1 mRNA transcription levels in hypothalamic and reduced the concentration of GABA-T, LH, and P4 in serum. At the same time, the initiation of the puberty was delayed, and led to disordered estrous cycle and reduced breastfeeding performance in adult female rats. This study showed that GABA-T affects the reproductive function of female rats by regulating the levels of Gnrh, Kiss1 and Rfrp-3 in the hypothalamus as well as the concentrations of LH and P4. This study explored the role of γ-aminobutyric acid transaminase (GABA-T) in the puberty and reproductive performance of female rats. Immunofluorescence technique, quantitative real-time PCR (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA) were used to detect the distribution of GABA-T and the expression of genes and hormones in female rats, respectively. The results showed that GABA-T was mainly distributed in the arcuate nucleus (ARC), paraventricular nucleus (PVN) and periventricular nucleus (PeN) of the hypothalamus, and in the adenohypophysis, ovarian granulosa cells and oocytes. Abat mRNA level at 28 d was lowest in the hypothalamus and the pituitary; at puberty, it was lowest in the ovary. Abat mRNA level was highest in adults in the hypothalamus; at infancy and puberty, it was highest in the pituitary; and at 21 d it was highest in the ovary. After vigabatrin (GABA-T irreversible inhibitor) was added to hypothalamus cells, the levels of Abat mRNA and Rfrp-3 mRNA were significantly reduced, but Gnrh mRNA increased at the dose of 25 and 50 μg/mL; Kiss1 mRNA was significantly increased but Gabbr1 mRNA was reduced at the 50 μg/mL dose. In prepubertal rats injected with vigabatrin, puberty onset was delayed. Abat mRNA, Kiss1 mRNA and Gnrh mRNA levels were significantly reduced, but Rfrp-3 mRNA level increased in the hypothalamus. Vigabatrin reduced the concentrations of GABA-T, luteinizing hormone (LH) and progesterone (P4), and the ovarian index. Lactation performance was reduced in adult rats with vigabatrin treatment. Four hours after vigabatrin injection, the concentrations of GABA-T and LH were significantly reduced in adult and 25 d rats, but follicle-stimulating hormone (FSH) increased in 25 d rats. In conclusion, GABA-T affects the reproductive function of female rats by regulating the levels of Gnrh, Kiss1 and Rfrp-3 in the hypothalamus as well as the concentrations of LH and P4. [ABSTRACT FROM AUTHOR]

In the present study, we evaluated how Ptprn-2 (encoding tyrosine phosphatase, receptor type, N2 polypeptide protein) affects the onset of puberty in female rats. We evaluated the expression of Ptprn- 2 mRNA and protein in the hypothalamus-pituitary-ovary axis of female rats using real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) and immunofluorescence at infancy, prepuberty, puberty, peripuberty, and adulthood. We evaluated the effects of Ptprn-2 gene knockdown on different aspects of reproduction-related biology in female rats, including the expression levels of puberty-related genes in vivo and in vitro , the time to onset of puberty, the concentration of serum reproductive hormones, the morphology of ovaries, and the ultrastructure of pituitary gonadotropin cells. Our results demonstrated that PTPRN-2 was primarily distributed in the arcuate nucleus (ARC), periventricular nucleus (PeN), adenohypophysis, and the ovarian follicular theca, stroma, and granulosa cells of female rats at various stages. Ptprn- 2 mRNA levels significantly varied between peripuberty and puberty (P < 0.05) in the hypothalamus and pituitary gland. In hypothalamic cells, Ptprn-2 knockdown decreased the expression of Ptprn-2 and Rfrp- 3 mRNA (P < 0.05) and increased the levels of Gnrh and Kiss- 1 mRNA (P < 0.05). Ptprn-2 knockdown in the hypothalamus resulted in delayed vaginal opening compared to the control group (n = 12, P < 0.01), and Ptprn-2 , Gnrh , and Kiss- 1 mRNA levels (P < 0.05) all decreased, while the expression of Igf-1 (P < 0.05) and Rfrp- 3 mRNA (P < 0.01) increased. The concentrations of FSH and P 4 in the serum of Ptprn-2 knockdown rats were lower than in control animals (P < 0.05). Large transverse perimeters and longitudinal perimeters (P < 0.05) were found in the ovaries of Ptprn-2 knockdown rats. There were fewer large secretory particles from gonadotropin cells in adenohypophysis tissue of the Ptprn-2 knockdown group compared to the control group. This indicates that Ptprn-2 knockdown can regulate levels of Gnrh , Kiss-1 , and Rfrp- 3 mRNA in the hypothalamus, regulate the concentration of serum FSH and P 4 , and alter the morphology of ovarian and gonadotropin cells, delaying the onset of puberty in female rats. • The expression levels of PTPRN-2 protein and mRNA change with age in the reproductive axis of female rats. • Knockdown Ptprn-2 can significantly delay the onset of puberty in female rats. • The Ptprn-2 gene knockdown regulates the levels of puberty-related genes and hormones in female rats. [ABSTRACT FROM AUTHOR]

Protein phosphorylation plays an important role in animal reproduction. However, its role in the onset of puberty in goats remains largely unexplored. Accordingly, in the present study, the molecular changes controlling the onset of puberty in goats were investigated by identifying the differentially phosphorylated proteins (DPPs) and phosphorylation sites (DPSs) in the hypothalami of prepubertal and pubertal female goats using LC–MS/MS and tandem mass tag labelling. A total of 3265 phosphopeptides corresponding to 1628 phosphoproteins were identified, including 234 upregulated and 342 downregulated phosphopeptides. The DPSs HTT, MAP1B, CAMKK1, MAP2, DNAJC5, and GAP43 were identified. These DPPs are enriched in the endocytosis, cAMP signaling, Rap1 signaling, melanogenesis, and insulin secretion pathways. These pathways are related to gonadotropin-releasing hormone and puberty. In particular, glucose-6-phosphate isomerase, fructose-bisphosphate aldolase C, and fructose-bisphosphate aldolase A occupy important locations in the protein-protein interaction network. These data provide evidence for a complex interaction network in goat hypothalamus proteins that affects puberty. Furthermore, they may help identify new puberty-regulating candidates and/or serve as an important resource for exploring the physiological mechanism of puberty onset in mammals. This study provides evidence for a complex interaction network in goat hypothalamus proteins that affects puberty. Furthermore, our data may help identify new puberty-regulating candidates and/or serve as an important resource for exploring the physiological mechanism of puberty onset in mammals. [Display omitted] • Protein phosphorylation in the hypothalamus of pubescent goats is investigated. • 3265 phosphopeptides corresponding to 1628 phosphoproteins are identified. • Endocytosis, cAMP signaling, Rap1 signaling pathways are enriched in pubertal goats. • Melanogenesis and insulin secretion pathways are also enriched in pubertal goats. [ABSTRACT FROM AUTHOR]

The functions of proteins at the onset of puberty in goats remain largely unexplored. To identify the proteins regulating puberty in goats, we analysed protein abundance and pathways in the hypothalamus of female goats. We applied tandem mass tag (TMT) labelling, liquid chromatography-tandem mass spectrometry (LC-MS/MS), and parallel reaction monitoring (PRM) to examine hypothalamus of pubertal (cases; n = 3) and prepubertal (controls; n = 3) goats. We identified 5119 proteins, including 69 differentially abundant proteins (DAPs), of which 35 were upregulated and 34 were downregulated. Fourteen DAPs were randomly selected to verify these results using PRM, and the results were consistent with the TMT quantitative results. DAPs were enriched in MAPK signalling pathway, Ras signalling pathway, Autophagy-animal, Endocytosis, and PI3K/Akt/mTOR signalling pathway categories. These pathways are related to embryogenesis, cell proliferation, cell differentiation, and promoting the release of gonadotropin-releasing hormone (GnRH) in the hypothalamus. In particular, PDGFRβ and MAP3K7 occupied important locations in the protein-protein interaction network. The results demonstrate that DAPs and their related signalling pathways are crucial in regulating puberty in goats. However, further research is needed to explore the functions of DAPs and their pathways to provide new insights into the mechanism of puberty onset. In domestic animals, reaching the age of puberty is an event that contributes significantly to lifetime reproductive potential. And the hypothalamus functions directly in the complex systemic changes that control puberty. Our study was the first TMT proteomics analysis on hypothalamus tissues of pubertal goats, which revealed the changes of protein and pathways that are related to the onset of puberty. We identified 69 DAPs, which were enriched in the MAPK signaling pathway, the Ras signaling pathway, and the IGF-1/PI3K/Akt/mTOR pathway, suggesting that these processes were probably involved in the onset of puberty. [Display omitted] • Proteomics was performed on hypothalamus of prepubertal and pubertal female goats. • MAPK, Ras, and autophagy-animal signalling pathways may regulate puberty onset. • Endocytosis and PI3K/Akt/mTOR signalling may also influence puberty onset. • PRM confirmed the DAPs identified by TMT analysis. [ABSTRACT FROM AUTHOR]