Update on the role of ovarian corticotropin-releasing hormone

Impact of FecB Mutation on Ovarian DNA Methylome in Small-Tail Han Sheep

Booroola fecundity (FecB) gene, a mutant of bone morphogenetic protein 1B (BMPR-1B) that was discovered in Booroola Merino, was the first prolificacy gene identified in sheep related to increased ovulation rate and litter size. The mechanism of FecB impact on reproduction is unclear.

METHODS

In this study, adult Han ewes with homozygous FecB(B)/FecB(B) mutations (Han BB group) and ewes with FecB(+)/FecB(+) wildtype (Han ++ group) were selected. Methylated DNA immunoprecipitation and high-throughput sequencing (MeDIP-seq) was used to identify differences in methylated genes in ovary tissue.

RESULTS

We examined differences in DNA methylation patterns between HanBB and Han ++ sheep. In both sheep, methylated reads were mainly distributed at the gene body regions, CpG islands and introns. The differentially methylated genes were enriched in neurotrophy in signaling pathway, Gonadotropin Releasing Hormone (GnRH) signaling pathway, Wnt signaling pathway, oocyte meiosis, vascular endothelial growth factor (VEGF) signaling pathway, etc. Differentially-methylated genes were co-analyzed with differentially-expressed mRNAs. Several genes which could be associated with female reproduction were identified, such as FOXP3 (forkhead box P3), TMEFF2 (Transmembrane Protein with EGF Like and Two Follistatin Like Domains 2) and ADAT2 (Adenosine Deaminase TRNA Specific 2).

CONCLUSIONS

We constructed a MeDIP-seq based methylomic study to investigate the ovarian DNA methylation differences between Small-Tail Han sheep with homozygous FecB mutant and wildtype, and successfully identified FecB gene-associated differentially-methylated genes. This study has provided information with which to understand the mechanisms of FecB gene-induced hyperprolificacy in sheep.

Classical music restored fertility status in rat model of premature ovarian failure

BACKGROUND

The restorative effect of classical music was assessed on the cyclophosphamide-induced animal model of premature ovarian failure (POF).

METHODS

Mozart's piano classical music (K.448) was used for up to 4 and 8 weeks. Rats were exposed to music 6 h every day using a stereo system with a volume of 65-70 dB. Sera and ovarian tissue samples were collected for the evaluation of FSH, LH, and E2 and histopathological examination. At the same time points, samples were taken from the hypothalamus and hippocampus to monitor the expression of Ntrk2, Crh, and Pomc using real-time PCR. Mating trial was performed to evaluate the fertility status of POF rats.

RESULTS

Histopathological examination revealed a significant increase (p < 0.05) in the numbers of morphologically normal follicles at all the developmental stages in POF rats after music therapy compared to the POF group (p < 0.05). Music therapy decreased FSH and LH levels to near-to-normal levels conidied with elevation of E2 (p < 0.05). Ntrk2, Crh, and Pomc expressions were down-regulated in POF rats. Music therapy increasaed the expression of Ntrk2 in the hypothalamus of POF rats (p < 0.05). In contrast, Crh and Pomc failed to reach the detection limit before intervention and four weeks after the intervention however, these genes were expressed eight weeks after music therapy. Fertility status was increased (p < 0.05) in terms of litter size in POF rats after being exposed to music compared to the non-treated POF control group (p < 0.05).

CONCLUSION

Results showed that music can exert therapeutic effects on POF rats via the alteration of sex-related hormones.

Psycho-emotional stress, folliculogenesis, and reproductive technologies: clinical and experimental data

Modern life, especially in large cities, exposes people to a high level of noise, high density of population, disrupted sleeping, large amount of excessive and controversial information as well as to other negative factors; all this may cause chronic psycho-emotional stress. The latest publications often use the term “Syndrome of megalopolis”, which means disruption of sleeping, high anxiety, and altered reproductive function. Medical treatment of infertility may also be considered as a stress factor, especially when infertility lasts for years and is aggravated with emotional frustration. Long-lasting distress may worsen health in general and suppress reproductive function, in particular. The review presents the data on the effects of maternal stress on folliculogenesis, especially when assisted reproductive technologies (ARTs) are used. Clinical data are presented alongside data from laboratory animal experiments. Different maternal stress models are taken into account in respect of their inf luence on oocyte maturation and embryo development. The interfering of psycho-emotional stress and reproductive function is the focus of the review. In these situations, exogenous hormones compensate for the stress-related disruption of the hypothalamic-pituitary-gonadal axis. When ARTs are implemented, stress-induced disruption of oogenesis is realized not via a decrease in hypothalamic and pituitary hormones, but by other ways, which involve paracrine mechanisms described in this review. Based on the literature analysis, one may conclude that stress negatively affects oocyte maturation in the ovary and suppresses subsequent embryo development. The role of some ovarian paracrine factors, such as BDNF, GDF-9, HB-EGF, TNF-α, and some others has been elucidated

Transcriptomic study of the mechanism by which the Kai Yu Zhong Yu recipe improves oocyte quality in a stressed mouse model

ETHNOPHARMACOLOGICAL RELEVANCE

The Kai Yu Zhong Yu recipe (KYZY) is a classic herbal formula in traditional Chinese medicine (TCM) that has been used to treat infertility associated with psychological stress for more than three hundred years.

AIM OF THE STUDY

Psychological stress has major impacts on fertility, with variable outcomes depending on the nature, strength, and duration of the stress. Stress can directly disturb ovulation, oocyte quality, maturation, and embryo development. The aim of this study is to investigate the molecular mechanism by which KYZY improves oocyte developmental potential under psychological stress.

MATERIALS AND METHODS

ICR female mice aged 4-5 weeks were randomly divided into five groups: control, stressed in the chronic unpredictable stress model (CUSM), and stressed plus KYZY treatment at 38.2 g/kg (KYZYH), 19.1 g/kg (KYZYM), or 9.6 g/kg (KYZYL). Ovary function was assessed by measuring serum levels of estradiol (E2), luteinizing hormone (LH), follicle-stimulating hormone (FSH), and anti-Müllerian hormone (AMH). Oocyte quality was evaluated in terms of reactive oxygen species (ROS) levels, apoptotic DNA fragmentation, and mitochondria distribution. We used RNA sequencing (RNAseq) to identify differentially expressed genes (DEGs) between groups and then further analyzed the DEGs for gene ontology (GO) term enrichment and protein-protein interactions.

RESULTS

Mice in the stressed group had reduced serum E2, LH, and FSH as well as increased ROS levels, increased apoptosis, and disturbed mitochondria distribution in oocytes. Treatment with KYZY at all three doses reversed or ameliorated these negative effects of stress. DEG analysis identified 187 common genes between the two comparisons (stressed vs. control and KYZYM vs. stressed), 33 of which were annotated with six gene ontology (GO)'s biological process (BP) terms: cell differentiation, apoptosis, ATP synthesis, protein homo-oligomerization, neuron migration, and negative regulation of peptidase activity. Protein-protein interaction network analysis of DEGs identified key hub genes. Notably, the genes Atp5o and Cyc1 were both involved in the ATP synthesis and among the top three hub genes, suggesting that regulation of oocyte mitochondrial electron transport and ATP synthesis is important in the response to stress and also is a possible mechanism of action for KYZY.

CONCLUSIONS

KYZY was effective in ameliorating the adverse effects of stress on oocyte competence, possibly by targeting the mitochondrial respiratory chain and ATP synthase.

Restraint stress and elevation of corticotrophin-releasing hormone in female mice impair oocyte competence through activation of the tumour necrosis factor α (TNF-α) system

Studies have observed that restraint stress (RS) and the associated elevation in corticotrophin-releasing hormone (CRH) impair oocyte competence by triggering apoptosis of ovarian cells but the underlying mechanisms are largely unclear. Although one study demonstrated that RS and CRH elevation triggered apoptosis in ovarian cells and oocytes via activating Fas/FasL signalling, other studies suggested that RS might damage cells by activating other pathways as well as Fas signalling. The objective of this study was to test whether RS and CRH elevation impairs oocytes by activating tumour necrosis factor α (TNF-α) signalling. Our invivo experiments showed that RS applied during oocyte prematuration significantly increased expression of TNF-α and its receptor (TNFR1) while inducing apoptosis in both oocytes and mural granulosa cells (MGCs). Invitro treatment of MGCs with CRH significantly increased their apoptotic percentages and levels of TNF-α and TNFR1 expression. Invitro knockdown by interfering RNA, invivo knockout of the TNF-α gene or injection of TNF-α antagonist etanercept significantly relieved the adverse effects of RS and CRH on apoptosis of MGCs and/or the developmental potential and apoptosis of oocytes. The results suggest that RS and CRH elevation in females impair oocyte competence through activating TNF-α signalling and that a TNF-α antagonist might be adopted to ameliorate the adverse effects of psychological stress on oocytes.

Investigating apoptotic, inflammatory, and growth markers in poor responders undergoing natural in vitro fertilization cycles: a pilot study

This study investigates follicular fluid (FF) from patients with poor and normal ovarian response undergoing natural assisted reproductive technology cycles. We report about (1) cell-free DNA (cfDNA), which reflects apoptosis; (2) corticotropin-releasing hormone (CRH); (3) interleukin (IL)-15, which reflects inflammation; (4) granulocyte colony-stimulating factor (G-CSF); (5) vascular endothelial growth factor (VEGF); and (6) insulin-like growth factor I (IGF-I), which reflects follicular growth. Forty-four poor responders and 44 normal responders-according to the Bologna criteria-were recruited. FF samples were prepared for cfDNA quantification employing Q-PCR and for CRH, IL-15, G-CSF, VEGF, and IGF-I quantification employing ELISA. Statistically nonsignificant different levels of FF cfDNA, CRH, IL-15, VEGF, and IGF-I were observed. Interestingly, statistically significant higher G-CSF levels were observed in normal responders (302.48 ± 474.36 versus 200.10 ± 426.79 pg/mL, P = 0.003). Lower cfDNA integrity was observed in cycles resulting in clinical pregnancy for both groups (normal: 0.07 ± 0.04 versus 0.25 ± 0.17 ng/μL, P < 0.001; poor: 0.10 ± 0.06 versus 0.26 ± 0.12 ng/μL, P < 0.001). The results predominantly showcase similarities between normal and poor responders pertaining to inflammatory, apoptotic, and growth factors. This may be attributed to the employment of natural cycles in order to exclude controlled ovarian stimulation as a factor-indicating its detrimental effect. As G-CSF levels presented significantly higher in normal responders, its vital role in understanding a compromised ovarian response is highlighted.

Review of psychological stress on oocyte and early embryonic development in female mice

Psychological stress can cause adverse health effects in animals and humans. Accumulating evidence suggests that psychological stress in female mice is associated with ovarian developmental abnormalities accompanied by follicle and oocyte defects. Oocyte and early embryonic development are impaired in mice facing psychological stress, likely resulting from hormone signalling disorders, reactive oxygen species (ROS) accumulation and alterations in epigenetic modifications, which are primarily mediated by the hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-ovarian (HPO) axes. The present evidence suggests that psychological stress is increasingly becoming the most common causative factor for female subfertility. Here, we review recent progress on the impact of psychological stress on female reproduction, particularly for oocyte and early embryonic development in female mice. This review highlights the connection between psychological stress and reproductive health and provides novel insight on human subfertility.

Investigation Trp64Arg polymorphism of the beta 3-adrenergic receptor gene in nonobese women with polycystic ovarian syndrome

Background

Polycystic ovary syndrome (PCOS) is a multifactorial and heterogeneous disease that has a potent inheritable component based on familial clustering. Despite many studies in the genetic field of PCOS, the genes that are involved in the causes of this syndrome have not been thoroughly investigated.

Objective

The purpose of this study was to establish the occurrence of the Trp64Arg polymorphism of beta3 adrenergic receptor in non-obese women with PCOS.

Materials and Methods

This cross-sectional study was performed on 100 women with PCOS and normal women as the control group in Imam Khomeini Hospital of Tehran in 2016-2017. Peripheral blood sample (2 cc) was obtained from two groups for genomic DNA based on the gene bank. Polymorphisms were genotyped by of using ADRB3 Trp64Arg. Then the DNA was extracted by genomic kiagen kit. The primer was analyzed for PCR based on gene bank by using Primer3 software and then confirmed by primer Blast tool at NCBI site to conformity to the beta-3 adrenergic receptor gene. The protein changes were assessment by the Clastal W software.

Results

The sequence analysis presented in NCBI, transcript variant 1, with the code NM_000025.2, shows changes in the amino acid sequence of exon 1 in women with PCOS. Polymorphism in the codon 64 encoding the amino acid tryptophan (W) occurred in the nucleotide c.T190C, which changed the nucleotide T to C and then the amino acid sequence of the tryptophan was altered to arginine pW64R.

Conclusion

T-C polymorphism is evident in the codon 64 of the adrenergic β3 receptor in patients with PCOS. Therefore, Beta3 adrenergic receptor gene polymorphism (Thr164Ile) associates with this syndrome in nonobese women.

Restraint-induced corticotrophin-releasing hormone elevation triggers apoptosis of ovarian cells and impairs oocyte competence via activation of the Fas/FasL system

Mechanisms by which psychological stress damages oocytes are largely undetermined. Although a previous study showed that the stress-induced corticotrophin-releasing hormone (CRH) elevation impaired oocyte competence by triggering apoptosis of ovarian cells, how CRH causes apoptosis in ovarian cells and oocytes is unknown. In this study, we have examined the hypothesis that restraint stress (RS)-induced CRH elevation triggers apoptosis of ovarian cells and impairs oocyte competence through activating the Fas/FasL system. The results showed that RS of female mice impaired oocyte competence, enhanced expression of CRH and CRH receptor (CRH-R) in the ovary, and induced apoptosis while activating the Fas/FasL system in mural granulosa cells (MGCs) and oocytes. Injecting mice with CRH-R1 antagonist antalarmin significantly alleviated the adverse effect of RS on oocyte developmental potential. Treatment of cultured MGCs recapitulated the effects of CRH and antalarmin on apoptosis and Fas/FasL expression in MGCs. Silencing FasL gene by RNA interference in cultured MGCs further confirmed the involvement of the Fas/FasL system in the CRH triggered apoptosis of ovarian cells. It is concluded that the RS-induced CRH elevation triggers apoptosis of ovarian cells and impairs oocyte competence via activation of the Fas/FasL system.

CRF and urocortin 3 protect the heart from hypoxia/reoxygenation-induced apoptosis in zebrafish

Fish routinely experience environmental hypoxia and have evolved various strategies to tolerate this challenge. Given the key role of the CRF system in coordinating the response to stressors and its cardioprotective actions against ischemia in mammals, we sought to characterize the cardiac CRF system in zebrafish and its role in hypoxia tolerance. We established that all genes of the CRF system, the ligands CRFa, CRFb, urotensin 1 (UTS1), and urocortin 3 (UCN3); the two receptor subtypes (CRFR1 and CRFR2); and the binding protein (CRFBP) are expressed in the heart of zebrafish: crfr1 > crfr2 = crfbp > crfa > ucn3 > crfb > uts1 In vivo, exposure to 5% O2 saturation for 15 min and 90 min of recovery resulted in four- to five-fold increases in whole heart crfb and ucn3 mRNA levels but did not affect the gene expression of other CRF system components. In vitro, as assessed by monitoring caspase 3 activity and the number of terminal deoxynucleotidyl transferase dUTP nick-end labeling-positive cells, pretreatment of excised whole hearts with CRF or UCN3 for 30 min prevented the increase in apoptosis associated with exposure to 1% O2 saturation for 30 min with a 24-h recovery. Lastly, the addition of the nonselective CRF receptor antagonist αh-CRF(9-41) prevented the cytoprotective effects of CRF. We show that the CRF system is expressed in fish heart, is upregulated by hypoxia, and is cytoprotective. These findings identify a novel role for the CRF system in fish and a new strategy to tolerate hypoxia.

Are CRH & NGF as psychoneuroimmune regulators in women with polycystic ovary syndrome?

PURPOSE

Polycystic ovary syndrome (PCOS) affects quality of life and can worsen anxiety and depression either due to the features of PCOS or due to the diagnosis of a chronic disease. Corticotrophin-releasing hormone (CRH) and nerves growth factor (NGF) are the modulator for the actions of the sympathetic nervous and immune systems.

METHODS

In total, 171 women divided into two groups: study and control groups. Serum CRH, NGF, and interleukins: IL-1α. IL-1β, 17A, and TNFα were determined by ELISA Kits in both groups.

RESULTS

The results showed that IL-1α (p < 0.001) and β (p = 0.017) significantly increased in PCO group. CRH, NGF, and IL-17α in serum of patients with PCO significantly lower than the control group (p < 0.001). The results of this study indicate: (1) destruction of three cytokines pattern, (2) Reduction of CRH, NGF, and IL-17α in serum of PCO patients can be under the direct influence of the sympathetic nervous system (SAS), and (3) reduction of CRH and NGFα can be reason of psych/emotional distress in women with PCOS.

CONCLUSIONS

The results of this study confirm (1) low-grade chronic inflammation in PCOS. This impaired cytokine pattern can play a major role in the immune-pathogenesis of PCOS; (2) hyponeurotrophinemia and reduction of CRH in women with PCOS could reflect deficit of neuronal stress-adaptation in these patients.

Key role of CRF in the skin stress response system

The discovery of corticotropin-releasing factor (CRF) or CRH defining the upper regulatory arm of the hypothalamic-pituitary-adrenal (HPA) axis, along with the identification of the corresponding receptors (CRFRs 1 and 2), represents a milestone in our understanding of central mechanisms regulating body and local homeostasis. We focused on the CRF-led signaling systems in the skin and offer a model for regulation of peripheral homeostasis based on the interaction of CRF and the structurally related urocortins with corresponding receptors and the resulting direct or indirect phenotypic effects that include regulation of epidermal barrier function, skin immune, pigmentary, adnexal, and dermal functions necessary to maintain local and systemic homeostasis. The regulatory modes of action include the classical CRF-led cutaneous equivalent of the central HPA axis, the expression and function of CRF and related peptides, and the stimulation of pro-opiomelanocortin peptides or cytokines. The key regulatory role is assigned to the CRFR-1α receptor, with other isoforms having modulatory effects. CRF can be released from sensory nerves and immune cells in response to emotional and environmental stressors. The expression sequence of peptides includes urocortin/CRF→pro-opiomelanocortin→ACTH, MSH, and β-endorphin. Expression of these peptides and of CRFR-1α is environmentally regulated, and their dysfunction can lead to skin and systemic diseases. Environmentally stressed skin can activate both the central and local HPA axis through either sensory nerves or humoral factors to turn on homeostatic responses counteracting cutaneous and systemic environmental damage. CRF and CRFR-1 may constitute novel targets through the use of specific agonists or antagonists, especially for therapy of skin diseases that worsen with stress, such as atopic dermatitis and psoriasis.

Prereproductive stress to female rats alters corticotropin releasing factor type 1 expression in ova and behavior and brain corticotropin releasing factor type 1 expression in offspring

BACKGROUND

Human and animal studies indicate that vulnerability to stress may be heritable and that changes in germline may mediate some transgenerational effects. Corticotropin releasing factor type 1 (CRF1) is a key component in the stress response. We investigated changes in CRF1 expression in brain and ova of stressed female rats and in the brain of their neonate and adult offspring. Behavioral changes in adulthood were also assessed.

METHODS

Adult female rats underwent chronic unpredictable stress. We extracted mature oocytes and brain regions from a subset of rats and mated the rest 2 weeks following the stress procedure. CRF1 expression was assessed using quantitative reverse-transcription polymerase chain reaction. Tests of anxiety and aversive learning were used to examine behavior of offspring in adulthood.

RESULTS

We show that chronic unpredictable stress leads to an increase in CRF1 messenger RNA expression in frontal cortex and mature oocytes. Neonatal offspring of stressed female rats show an increase in brain CRF1 expression. In adulthood, offspring of stressed female rats show sex differences in both CRF1 messenger RNA expression and behavior. Moreover, CRF1 expression patterns in frontal cortex of female offspring depend upon both maternal and individual adverse experience.

CONCLUSIONS

Our findings demonstrate that stress affects CRF1 expression in brain but also in ova, pointing to a possible mechanism of transgenerational transmission. In offspring, stress-induced changes are evident at birth and are thus unlikely to result from altered maternal nurturance. Finally, brain CRF1 expression in offspring depends upon gender and upon maternal and individual exposure to adverse environment.