Hypothalamic Transcriptome Analysis Reveals the Crucial MicroRNAs and mRNAs Affecting Litter Size in Goats

Abstract

The hypothalamus was the coordination center of the endocrine system, which played an important role in goat reproduction. However, the molecular mechanism of hypothalamus regulating litter size in goats was still poorly understood. This study aims to investigate the key functional genes associated with prolificacy by hypothalamus transcriptome analysis of goats. In this research, an integrated analysis of microRNAs (miRNAs)-mRNA was conducted using the hypothalamic tissue of Yunshang black goats in the follicular stage. A total of 72,220 transcripts were detected in RNA-seq. Besides, 1,836 differentially expressed genes (DEGs) were identified between high fecundity goats at the follicular phase (FP-HY) and low fecundity goats at the follicular phase (FP-LY). DEGs were significantly enriched in 71 Gene Ontology (GO) terms and 8 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. The transcriptome data suggested that DEGs such as BMPR1B, FGFR1, IGF1 and CREB1 are directly or indirectly involved in many processes like hypothalamic gonadal hormone secretion. The miRNA-seq identified 1,837 miRNAs, of which 28 differentially expressed miRNAs (DEMs). These DEMs may affect the nerve cells survival of goat hypothalamic regulating the function of target genes and further affect the hormone secretion activities related to reproduction. They were enriched in prolactin signaling pathway, Jak-STAT signaling pathway and GnRH signaling pathway, as well as various metabolic pathways. Integrated analysis of DEMs and DEGs showed that 87 DEGs were potential target genes of 28 DEMs. After constructing a miRNA-mRNA pathway network, we identified several mRNA-miRNAs pairs by functional enrichment analysis, which was involved in hypothalamic nerve apoptosis. For example, NTRK3 was co-regulated by Novel-1187 and Novel-566, as well as another target PPP1R13L regulated by Novel-566. These results indicated that these key genes and miRNAs may play an important role in the development of goat hypothalamus and represent candidate targets for further research. This study provides a basis for further explanation of the basic molecular mechanism of hypothalamus, but also provides a new idea for a comprehensive understanding of prolificacy characteristics in Yunshang black goats.

Integrated Transcriptome Analysis Reveals the Crucial mRNAs and miRNAs Related to Fecundity in the Hypothalamus of Yunshang Black Goats during the Luteal Phase

“…Studies have found that many miRNAs are involved in a variety of biological regulation processes in the hypothalamus, such as immune response [ 30 ], osmotic regulation [ 31 ], and so on. In this study, miR-9 is the most abundant miRNA in the hypothalamus of Yunshang black goats, during the luteal phase, which was consistent with the results of the follicular phase in the previous [ 32 ]. It has been reported that miR-9 is mainly expressed in neural tissues in mammals, such as mice and humans [ 33 ], and regulates BAF53a (also known as ACTL6A , actin like 6A) [ 34 ], stathmin [ 35 ] and other genes involved in the proliferation, migration, and other activities of the nerve cells.…”

Transcriptomic Changes of Photoperiodic Response in the Hypothalamus Were Identified in Ovariectomized and Estradiol-Treated Sheep

“…Early reports have presented evidence that the sheep hypothalamus plays a vital role in photoperiod-induced reproductive regulation, and that responsiveness to the photoperiod is a key factor that affects ovine puberty onset ( Plant, 2015 ), the estrous cycle transition, and reproductive hormone regulation ( Smith, et al, 2007 ; Smith, 2012 ; Li, et al, 2019 ). In previous study, OVX animals have been studied to analyze the mechanism of hormonal feedback, and the location of the major functional area of hypothalamus was in goats ( Muñoz, et al, 2017 ; Liang et al, 2021 ) and sheep ( Goodman, et al, 2011 ; Weems, et al, 2017 ; Zhang, et al, 2019 ; Dardente, et al, 2019 ); several key genes related to the photoperiodic response, such as KISS1 , RFRP , and DI O 2/DI O 3 , were identified in these studies. However, few studies have focused on hypothalamic photoperiod regulation at the whole transcriptome level.…”

“…In the current study, most omics studies of the hypothalamus have focused on differences in gene expression profiles based on the different estrus periods or some important economic traits with significant differences in animals ( Gao, et al, 2018 ; Hou, et al, 2018 ; Gley, et al, 2019 ; Zhang, et al, 2019 ; Liang, et al, 2021 ). For example, it was found that the seasonal energy balance of Siberian hamsters was affected by the species-specific responsiveness of hypothalamic T3 ( Bao, et al, 2019 ), and that the hypothalamus was also involved in the circadian of metabolism ( Cedernaes, et al, 2019 ) and daylength response ( Sáenz De Miera et al, 2017 ).…”

Are Copy Number Variations within the FecB Gene Significantly Associated with Morphometric Traits in Goats?

“…The hypothalamus regulates the release of growth hormones [ 36 ]. Thus, we hypothesized that the Fec B gene might influence morphometric traits by altering hypothalamic function [ 37 ]. Additionally, this gene could inhibit BMP signalling, which is essential for chondrogenesis and for regulating multiple growth plate features, by competitive binding to SPARC-related modular calcium binding 2 ( SMOC2 ).…”