Integrative proteomic and transcriptomic analysis in the female goat ovary to explore the onset of puberty.

Puberty is considered a prerequisite for affecting reproductive performance and productivity. Little was known about molecular changes in pubertal goat ovaries. Therefore, we measured and performed a correlation analysis of the mRNA and proteins changes in the pre-pubertal and pubertal goat ovaries. The results showed that only six differentially expressed genes and differentially abundant proteins out of 18,139 genes and 7550 proteins quantified had significant correlations. CNTN2 and THBS1, discovered in the mRNA-mRNA interaction network, probably participated in pubertal and reproductive regulation by influencing GnRH receptor signals, follicular development, and ovulation. The predicted core transcription factors may either promote or inhibit the expression of reproductive genes and act synergistically to maintain normal reproductive function in animals. The interaction between PKM and TIMP3 with other proteins may impact animal puberty through energy metabolism and ovarian hormone secretion. Pathway enrichment analyses revealed that the co-associated key pathways between ovarian genes and proteins at puberty included calcium signalling pathway and olfactory transduction. These pathways were associated with gonadotropin-releasing hormone synthesis and secretion, signal transmission, and cell proliferation. In summary, these results enriched the potential molecules and signalling pathways that affect puberty and provided new insights for regulating and promoting the onset of puberty. SIGNIFICANCE: This study conducted the first transcriptomic and proteomic correlation analysis of pre-pubertal and pubertal goat ovaries and identified six significantly correlated molecules at both the gene and protein levels. Meanwhile, we were drawn to several molecules and signalling pathways that may play a regulatory role in the onset of puberty and reproduction by influencing reproductive-related gene expression, GnRH receptor signals, energy metabolism, ovarian hormone secretion, follicular development, and ovulation. This information contributed to identify potential biomarkers in pubertal goat ovaries, which was vital for predicting the onset of puberty and improving livestock performance.

Quantitative proteomics analysis to assess protein expression levels in the ovaries of pubescent goats.

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.