Current status of the role of endothelins in regulating ovarian follicular function: A review

Granulosa cell function in domestic animals: A review on the in vitro effects of FSH, insulin and insulin-like growth factor 1

Ovarian granulosa cells produce a variety of biologically active compounds in addition to steroid hormones that include numerous families of growth factors, cytokines and adipokines. Many of these function as endocrine, paracrine and autocrine hormones to regulate ovarian activity. The goal of this review is to provide an update on the evidence in domestic animals on how FSH, insulin and IGF1 regulate the function of granulosa cells with a focus on ovarian steroidogenesis and cell proliferation with comparisons across six domestic animals: pigs, cattle, horses, water buffalo, goats and sheep. In most species, FSH was not a mitogenic stimulus to granulosa cells whereas insulin and IGF1 were stimulatory to cell proliferation in the species it was evaluated. FSH, insulin and IGF1 were all stimulatory to granulosa cell steroidogenesis in the species it was studied. More research is needed to evaluate the role of insulin in the regulation of cell proliferation and steroidogenesis in water buffalo and goats. The role of IGF1 in regulating granulosa cell function in horses also needs further study. Most granulosa-cell secreted factors have direct effects (either positive or negative) on FSH-, insulin- and IGF1-induced steroid production in ovarian cells, but how they all work together to create a cumulative effect to regulate fertility will require further research.

A tale of two endothelins: the rise and fall of the corpus luteum

Endothelins are small 21 amino acid peptides that interact with G-protein-coupled receptors. They are highly conserved across species and play important roles in vascular biology as well as in disease development and progression. Endothelins, mainly endothelin-1 and endothelin-2, are intricately involved in ovarian function and metabolism. These two peptides differ only in two amino acids but are encoded by different genes, which suggests an independent regulation and a cell-specific mode of expression. This review aims to comprehensively discuss the distinct regulation and roles of endothelin-1 and endothelin-2 regarding corpus luteum function throughout its life span.

MAGEA6 positively regulates MSMO1 and promotes the migration and invasion of oesophageal cancer cells

The melanoma antigen gene family A (MAGEA) family of proteins comprises of cancer-testis antigens that are highly expressed in a number of tumours but are minimally expressed in normal cells. Due to its expression characteristics, this protein family has become a popular target for anti-cancer drugs and immunotherapy research over recent years. Although, elevated expression levels of MAGEA6 has been found in different types of tumours, there remains to be insufficient information on the function of MAGEA6 and its associated gene regulation pathways. The present study used Transwell, Cell Counting Kit-8 and wound healing assays to analyse the effects of MAGEA6 on Eca109 cell invasion, migration and proliferation. The main functions and pathways involved in MAGEA6 were predicted by Illumina Hiseq screening for mutually regulated genes and core genes. Eca109 cell line with a high expression of MAGEA6 was a stable cell line obtained by transfection in the early stage, and this cell line was used in subsequent experiments. Transcriptome sequencing was performed on this cell line and the Eca109 cell line that normally expressed MAGEA6. It was revealed that a high expression of MAGEA6 conferred a significant stimulating effect on cell proliferation whilst also significantly increasing cell invasion and migration. Transcriptomic analysis identified 14 differentially expressed genes and 13 core regulatory genes closely associated with MAGEA6 expression regulation, such as methylsterol monooxygenase 1 (MSMO1). The present study suggest that MAGEA6 positively regulated MSMO1 expression, which may serve an oncogenic role in cells through this regulatory effect. Overall, this provided a novel route of investigation for an in-depth study of the regulatory function of MAGEA6.

Role of RGMc as a Neogenin Ligand in Follicular Development in the Ovary

There is currently no cure for infertility in women with a poor ovarian response (POR). Neogenin is reported to be abundantly expressed in the ovary; however, its role in mammalian follicular development is unclear and its ligand and signaling pathway remain uncertain. We systematically investigated the role of neogenin and the ligand repulsive guidance molecule c (RGMc) during follicular development. We treated hyperstimulated mouse ovaries with RGMc and analyzed follicular development. Furthermore, we investigated clusters of up/downregulated genes in RGMc-treated ovaries using whole-transcriptome next-generation sequencing (NGS). In addition, we investigated whether expression of up/downregulated factors identified by NGS was also altered in cumulus cells (CCs) of patients with a POR. The number of oocytes was 40% higher in RGMc-treated ovaries than in control ovaries. NGS data indicated that prostaglandin D2 (PGD2) was involved in the RGMc signaling pathway during follicular development. RGMc treatment significantly elevated the PGD2 level in culture medium of CCs obtained from patients with a POR. Our results demonstrate that RGMc as neogenin ligand promotes follicular development in ovaries via the PGD2 signaling pathway. Therefore, it may be possible to use RGMc for ovarian stimulation in patients with a POR.

Cranial irradiation alters neuroinflammation and neural proliferation in the pituitary gland and induces late-onset hormone deficiency

Cranial radiotherapy induces endocrine disorders and reproductive abnormalities, particularly in long-term female cancer survivors, and this might in part be caused by injury to the pituitary gland, but the underlying mechanisms are unknown. The aim of this study was to investigate the influence of cranial irradiation on the pituitary gland and related endocrine function. Female Wistar rat pups on postnatal day 11 were subjected to a single dose of 6 Gy whole-head irradiation, and hormone levels and organ structure in the reproductive system were examined at 20 weeks after irradiation. We found that brain irradiation reduced cell proliferation and induced persistent inflammation in the pituitary gland. The whole transcriptome analysis of the pituitary gland revealed that apoptosis and inflammation-related pathways were up-regulated after irradiation. In addition, irradiation led to significantly decreased levels of the pituitary hormones, growth hormone, adrenocorticotropic hormone, thyroid-stimulating hormone and the reproductive hormones testosterone and progesterone. To conclude, brain radiation induces reduction of pituitary and reproduction-related hormone secretion, this may due to reduced cell proliferation and increased pituitary inflammation after irradiation. Our results thus provide additional insight into the molecular mechanisms underlying complications after head irradiation and contribute to the discovery of preventive and therapeutic strategies related to brain injury following irradiation.

The EDN2 rs110287192 gene polymorphism is associated with paratuberculosis susceptibility in multibreed cattle population

Paratuberculosis (pTB), also known as Johne's disease (JD), is a contagious, chronic, and granulomatous inflammatory disease of the intestines of ruminants which is caused by Mycobacterium avium subsp. paratuberculosis (MAP) infection, resulting in billions of dollars in economic losses worldwide. Since, currently, no effective cure is available for MAP infection, it is important to explore the genetic variants that affect the host MAP susceptibility. The aim of this study was to analyze a potential association between EDN2 synonymous gene mutations (rs110287192, rs109651404 and rs136707411), that modifies susceptibility to pTB. EDN2 rs110287192, rs109651404 and rs136707411 mutations were genotyped in 68 infected and 753 healthy animals from East Anatolian Red crossbred, Anatolian Black crossbred and Holstein breed cattle by using Custom TaqMan SNP Genotyping Assays. For pTB status, serum antibody levels S/P ≥ 1.0 were assessed in carriers of the different EDN2 genotypes. EDN2 rs110287192 mutation showed a significant association with bovine pTB (adj. p < 0.05). For rs110287192 locus, the odd ratios for GG and TG genotypes versus TT genotypes were 1.73; (95% CI = 0.34–8.59) and 0.53 (95% CI = 0.12–2.37) respectively, which indicated that proportion of TG heterozygotes were significantly higher in control animals as compared to pTB animals. On the other hand, while rs136707411 mutation showed a suggestive association with pTB status in the examined cattle population (nominal p < 0.05); no association was detected between rs109651404 genotypes and pTB status. Selecting animals against rs110287192-GG genotype may decrease the risk of pTB in cattle of the Bos taurus taurus subspecies.

Genomic Analysis Reveals Pleiotropic Alleles at EDN3 and BMP7 Involved in Chicken Comb Color and Egg Production

Artificial selection is often associated with numerous changes in seemingly unrelated phenotypic traits. The genetic mechanisms of correlated phenotypes probably involve pleiotropy or linkage of genes related to such phenotypes. Dongxiang blue-shelled chicken, an indigenous chicken breed of China, has segregated significantly for the dermal hyperpigmentation phenotype. Two lines of the chicken have been divergently selected with respect to comb color for over 20 generations. The red comb line chicken produces significantly higher number of eggs than the dark comb line chicken. The objective of this study was to explore potential mechanisms involved in the relationship between comb color and egg production among chickens. Based on the genome-wide association study results, we identified a genomic region on chromosome 20 involving EDN3 and BMP7, which is associated with hyperpigmentation of chicken comb. Further analyses by selection signatures in the two divergent lines revealed that several candidate genes, including EDN3, BMP7, BPIFB3, and PCK1, closely located on chromosome 20 are involved in the development of neural crest cell and reproductive system. The two genes EDN3 and BMP7 have known roles in regulating both ovarian function and melanogenesis, indicating the pleiotropic effect on hyperpigmentation and egg production in blue-shelled chickens. Association analysis for egg production confirmed the pleiotropic effect of selected loci identified by selection signatures. The study provides insights into phenotypic evolution due to genetic variation across the genome. The information might be useful in the current breeding efforts to develop improved breeds for egg production.

Transcriptome analysis of ovary in relatively greater and lesser egg producing Jinghai Yellow Chicken

Egg production is determined by the function of ovary and is regulated by the hypothalamic-pituitary-ovary axis. The mechanism by which the ovary regulates egg production, however, is still poorly understood. The purpose of this study is to compare the transcriptome difference in ovary of relatively greater and lesser egg producing chickens, and to screen candidate genes related to egg production. A RNA sequencing was performed to analyze and compare the mRNA in ovarian tissues of relatively greater and lesser egg producing chickens. A total of 4 431 new genes expressed in the chicken ovary were mined. There were 305 differentially expressed genes (DEGs) identified between the relatively greater and lesser egg producing hens. Gene ontology analysis identified five candidate genes related to egg production, including ZP2, WNT4, AMH, IGF1, and CYP17A1 genes. Tissue expression profiles indicated these five candidate genes were highly expressed in chicken ovarian tissues, indicating a potential role in regulating chicken ovarian function and egg production. The KEGG analysis indicated the neuroactive ligand-receptor interaction pathway might have an important function in regulation of egg production. In addition, four known pathways related to reproduction were detected, including the calcium signaling, wnt signaling pathway, focal adhesion, and cytokine-cytokine receptor interaction pathways. Results of the present study indicate gene expression differences in the ovarian tissues of relatively greater and lesser egg producing chickens, and identified five important candidate genes related to egg production, which provided a theoretical basis for improving egg production of Jinghai Yellow Chickens.

Endothelins and their receptors in embryo implantation

As a critical stage of pregnancy, the implantation of blastocysts into the endometrium is a progressive, excessively regulated local tissue remodeling step involving a complex sequence of genetic and cellular interplay executed within an optimal time frame. For better understanding the causes of infertility and, more importantly, for developing powerful strategies for successful implantations and combating infertility, an increasing number of recent studies have been focused on the identification and study of newly described substances in the reproductive tree. The endothelins (ET), a 21-aminoacidic family of genes, have been reported to be responsible for the contraction of vascular and nonvascular smooth muscles, including the smooth muscles of the uterus. Therefore, this review aims to comprehensively discuss the physiological role of endothelins and signaling through their receptors, as well as their probable involvement in the implantation process.