Chlorobisphenol A activated kisspeptin/GPR54-GnRH neuroendocrine signals through ERα and GPER pathway in neuronal GT1-7 cells.

Chlorobisphenol A (ClxBPA) is a kind of novel estrogenic compounds. The present study aims to investigate the effects of three ClxBPA compounds on the kisspeptin/G protein-coupled receptor 54 (GPR54, also named KissR1)-gonadotropin-releasing hormone (GnRH) (KGG) system in neuronal GT1-7 cells with mechanistic insights by estrogen receptor signaling pathways. The study demonstrated that low-concentration ClxBPA induced the cell proliferation, promoted GnRH secretion, upregulated the expression of KGG neuroendocrine signal-related proteins (KissR1, GnRH1 and kisspeptin) and genes including Kiss1, GnRH1, KissR1, luteinizing hormone receptor (Lhr) and follicle-stimulating hormone receptor (Fshr) in GT1-7 cells. Additionally, ClxBPA activated nuclear estrogen receptor alpha (ERα) and member estrogen receptor G protein-coupled estrogen receptor (GPER)-regulated phosphatidylinositol-3-kinase/protein kinase B (PI3K/Akt) and extracellular signal-regulated kinase (Erk1/2) signaling pathways. Pretreatment of GT1-7 cells with GPER inhibitor G15 and ERα inhibitor ICI reduced the expression of KissR1, GnRH1 and kisspeptin proteins, attenuated mRNA levels of Kiss1, GnRH1, KissR1, Fshr and Lhr genes, and decreased ClxBPA-induced GT1-7 cell proliferation. The results suggested that ClxBPA activated the KGG neuroendocrine signals and induced the proliferation of GT1-7 cells via ERα and GPER signaling pathways. This study provides a new perspective to explore the neuroendocrine toxicity mechanism of ClxBPA. CAPSULE: ClxBPA activated KGG neuroendocrine signaling pathway via ERα and GPER and induced the proliferation of GT1-7 cells.

Neonatal and juvenile exposure to perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS): Advance puberty onset and kisspeptin system disturbance in female rats.

Perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) are widespread and persistent chemicals in the environment, and limited data about their effects on puberty development are available. In order to explore the effects of neonatal and juvenile PFOA/PFOS exposure on puberty maturation, female rats were injected with PFOA or PFOS at 0.1, 1 and 10 mg/kg/day during postnatal day (PND) 1-5 or 26-30. The day of vaginal opening (VO) and first estrus were significantly advanced in 10 mg/kg PFOA, 1 and 10 mg/kg PFOS groups after neonatal and juvenile exposure. Besides, neonatal PFOA/PFOS exposure increased body weight and anogenital distance (AGD) in a non-dose-dependent manner. Estradiol and luteinizing hormone levels were also increased with more frequent occurrences of irregular estrous cycles in 0.1 and 1 mg/kg PFOA/PFOS exposure groups. Although no altered ovarian morphology was observed, follicles numbers were reduced in neonatal groups. Kiss1, Kiss1r and ERα mRNA expressions were downregulated after two periods' exposure in the hypothalamic anteroventral periventricular (AVPV) and arcuate (ARC) nuclei. PFOA/PFOS exposure also suppressed kisspeptin fiber intensities, especially at the high dose. In conclusion, neonatal and juvenile are critical exposure periods, during which puberty maturation may be vulnerable to environmental exposure of PFOA/PFOS, and kisspeptin system plays a key role during these processes.

The negative effects of chronic exposure to isoflurane on spermatogenesis via breaking the hypothalamus-pituitary-gonadal equilibrium.

This study aims to investigate the negative effects of chronic exposure to isoflurane on spermatogenesis and explore the underlying mechanisms. Sixty male rats were randomly allocated to two groups: control group, receiving no treatment, and anesthesia group, administrated exposure to isoflurane (2 ppm) for 25 consecutive days (1 h/day). The negative effects of chronic exposure to isoflurane were evaluated by analyzing the median eminence GnRH content, the relevant hormone levels, some sperm parameters and the mRNA expressions for some reproduction-related genes. Isoflurane significantly decreased the GnRH content and the serum gonadotrophin levels compared with the control group (p<0.01). Meanwhile, the mRNA expressions of GnRH in hypothalamus, GnRH receptor, luteinizing hormone (LH)-ß and follicle-stimulating hormone (FSH)-ß in pituitary, and LH receptor and FSH receptor in testes were also significantly inhibited (p<0.01). Furthermore, the mRNA expressions of androgen receptor (AR), kisspeptin encoded gene (Kiss-1) and its receptor (GPR54) in hypothalamus were significantly diminished by isoflurane (p<0.01). The results indicated that chronic exposure to isoflurane diminished the synthesis and secretion of GnRH by inhibiting the androgen-AR-Kisspeptin-GPR54 pathway and breaking the hypothalamic-pituitary-gonadal equilibrium, and therefore it could inhibit spermatogenesis.

Jiawei Buzhong Yiqi Decoction attenuates polycystic ovary syndrome through regulating kisspeptin-GPR54-AKT-SHBG system.

BACKGROUND: Polycystic ovary syndrome (PCOS) is one of the most common reproductive endocrine disorders. Accumulated evidence has suggested the indispensable role of kisspeptin-G protein-coupled receptor (GPR54) system and SHBG in development of PCOS. However, potential mechanisms and their relationship are unclear. Jiawei Buzhong Yiqi Decoction (JWBZYQ) has been reported to ameliorate obese PCOS. Whereas, potential mechanisms remain elusive. PURPOSE: To determine whether JWBZYQ attenuates PCOS by regulating the kisspeptin-GPR54 system and SHBG production. And to explore potential mechanisms. METHODS: An overweight PCOS rat model was developed with testosterone propionate (TP) and high-fat diet (HFD). The efficacy of JWBZYQ was assessed by tracking changes in weight, estrous cycle, ovarian morphology, and serum sex hormone levels. Additionally, kisspeptin-GPR54 system expression in multiple organs and PI3K-AKT pathway activity in liver of different rats were detected. Modifications in SHBG production were also measured. Kisspeptin54 was administered to establish a cellular model. The levels of AKT phosphorylation and SHBG protein within HepG2 cells were analyzed. Finally, confirmatory studies were performed using AKT phosphorylation activator and inhibitor. RESULTS: JWBZYQ effectively attenuated the overweight, disrupted estrous cycle, altered sex hormone levels, and aberrant ovarian morphology in PCOS rats. Meanwhile, PCOS rats exhibited elevated levels of kisspeptin and GPR54, along with reduced SHBG levels, which could be reversed by JWBZYQ. These alterations might be connected with the activation of AKT phosphorylation. In vitro experiment identified that JWBZYQ could rectify the hyperactivated AKT phosphorylation and deficient production of SHBG caused by kisspeptin54. CONCLUSIONS: Overexpressed kisspeptin-GPR54 system inhibited SHBG synthesis in PCOS. JWBZYQ curtailed the exorbitant expression of kisspeptin and GPR54, which moderated the rise in AKT phosphorylation and subsequently promoted the production of SHBG.

Effects of trichlorobisphenol A on the expression of proteins and genes associated with puberty initiation in GT1-7 cells and the relevant molecular mechanism.

This study evaluated the effects of Cl3BPA on kisspeptin-G-protein coupled receptor 54 (GPR54)/gonadotropin-releasing hormone (GnRH) (KGG) signals and analyzed the roles of estrogen receptor alpha (ERɑ) and G-protein coupled estrogen receptor 1 (GPER1) in regulating KGG signals. The results showed that Cl3BPA at 50 µM increased the levels of intracellular reactive oxygen species (ROS) and GnRH, upregulated the protein levels of kisspeptin and the expression of fshr, lhr and gnrh1 genes related to KGG in GT1-7 cells. In addition, 50 µM Cl3BPA significantly upregulated the phosphorylation of extracellular regulated protein kinases 1/2 (Erk1/2), the protein levels of GPER1 and the expression of the gper1 as well as the most target genes associated with mitogen-activated protein kinase (MAPK)/Erk1/2 pathways. Specific signal inhibitor experiments found that Cl3BPA activated KGG signals by activating the GPER1-mediated MAPK/Erk1/2 signaling pathway at the mRNA level. A docking test further confirmed the interactions between Cl3BPA and GPER1. The findings suggest that Cl3BPA might induce precocious puberty by increasing GnRH secretion together with KGG signaling upregulation, which is driven by GPER1-mediated signaling pathway. By comparison, ClxBPAs with fewer chlorine atoms had more obvious effects on the expression of proteins and partial genes related to KGG signals in GT1-7 cells.

Gut microbiota is associated with the effect of photoperiod on seasonal breeding in male Brandt's voles (Lasiopodomys brandtii).

BACKGROUND: Seasonal breeding in mammals has been widely recognized to be regulated by photoperiod, but the association of gut microbiota with photoperiodic regulation of seasonal breeding has never been investigated. RESULTS: In this study, we investigated the association of gut microbiota with photoperiod-induced reproduction in male Brandt's voles (Lasiopodomys brandtii) through a long-day and short-day photoperiod manipulation experiment and fecal microbiota transplantation (FMT) experiment. We found photoperiod significantly altered reproductive hormone and gene expression levels, and gut microbiota of voles. Specific gut microbes were significantly associated with the reproductive hormones and genes of voles during photoperiod acclimation. Transplantation of gut microbes into recipient voles induced similar changes in three hormones (melatonin, follicle-stimulating hormone, and luteinizing hormone) and three genes (hypothalamic Kiss-1, testicular Dio3, and Dio2/Dio3 ratio) to those in long-day and short-day photoperiod donor voles and altered circadian rhythm peaks of recipient voles. CONCLUSIONS: Our study firstly revealed the association of gut microbiota with photoperiodic regulation of seasonal breeding through the HPG axis, melatonin, and Kisspeptin/GPR54 system. Our results may have significant implications for pest control, livestock animal breeding, and human health management. Video Abstract.

Expression patterns of kiss2 and gpr54-2 in Monopterus albus suggest these genes may play a role in sex reversal in fish.

Due to its exceptionally small genome size and protogynous hermaphroditism, Monopterus albus has been proposed as a model for vertebrate sexual development. The Kiss/GPR54 system is a central regulator of sexual development in most vertebrates, but its role in sex reversal remains hypothetical. In contrast to mammals, fishes often possess more than one copy of the kiss and gpr54 genes. Our objectives were to identify all kiss/gpr54 genes in the genome of M. albus and to assess their involvement in sex reversal via their expression patterns (qPCR) in females, males, and intersex specimens. We identified only two genes: kiss2 and gpr54-2. kiss2 expression was extremely high in the gonads of males, intermediate in females, and low in intersex; and reduced in all tissues of intersex. gpr54 expression was also extremely high in the gonads of males, high in intersex, but low in females. gpr54 expression in brain was high in all three sexes. In conclusion, (a) kiss1 has been functionally replaced in M. albus; (b) the functions of gpr54-2 in brain are not sex-specific; (c) kiss2 appears to undergo a 'reset' in the expression during the sex change; and (d) sex-specific expression patterns in the gonads indicate that these two genes may play a role in sex reversal in fish.

The effect of neonatal immune challenge on reproduction by altering intraovarian kisspeptin/GPR54 system in the rat.

Immune challenge in early life has been observed to influence the long-term reproductive dysfunction. On PNDs 3 and 5, female offsprings were administered with LPS (50µg/kg, i.p.) or saline. Vaginal opening was recorded, and oestrous cyclicity was monitored immediately post puberty and again at 56-70 days. At 10 weeks of age, the ovaries were removed for immunostaining and RNA analysis. Neonatal exposure to LPS resulted in a significant delay puberty onset as well as destroyed expression of ovulation related genes. At PND 42 and 70, a significant increase in Kiss1 mRNA and Kisspeptin expression was detected at proestrus and oestrus in neo-LPS treated rats compared with the counterparts. Therefore, neonatal LPS exposure had a long-term effect on reproductive function and the up-regulated expression of ovarian Kiss1 and kisspeptin during the ovulatory transition stage may contribute to ovulatory dysfunction induced by peripheral LPS administration in early life.

Short-term neonatal/prepubertal exposure of dibutyl phthalate (DBP) advanced pubertal timing and affected hypothalamic kisspeptin/GPR54 expression differently in female rats.

Dibutyl phthalate (DBP) had been widely used and its exposure in children has been thought to be one of the reasons causing a trend of advanced pubertal timing in girls. Puberty starts from hypothalamic gonadotropin-releasing hormone release which is controlled by many factors including neurotransmitter kisspeptin and its receptor GPR54. These neural organization or reorganization happens in hypothalamus during neonatal or prepubertal period which may be two target windows of DBP exposure. The present study was designed to determine: (1) the difference between the effects of neonatal and prepubertal DBP exposure on female pubertal timing; (2) whether kisspeptin/GPR54 expression in hypothalamus would respond to neonatal and prepubertal DBP exposure differently. Female Sprague-Dawley rats were exposed by subcutaneous injection of 0.5, 5 and 50mg/kg DBP during Postnatal day (P)1-5 (neonatal) or P26-30 (prepubertal). Physiological data demonstrated that both neonatal and prepubertal DBP exposure could advance pubertal timing significantly accompanied by irregular estrous cycles but only a little gonadal impairment. Exposure-period-related difference was found significant with prepubertal exposure groups having longer estrous cycle duration, heavier at vaginal opening and having higher serum estradiol level compared with neonatal exposure groups. Molecular data showed an up-regulated trend in kisspeptin mRNA and immunoreactivity levels of hypothalamic area arcuate but a down-regulation in GPR54 mRNA expression after P1-5 DBP treatment. In P26-30 groups, kisspeptin mRNA and immunoreactivity levels tended to be lower after DBP treatment. These results demonstrated small dose of DBP could induce earlier pubertal timing in females and both neonatal and prepubertal periods were critical windows for DBP exposure.

Role of kisspeptin/GPR54 signaling pathways in prompting formation of precocious puberty / 中国病理生理杂志

[ABSTRACT]AIM:Toexploretheroleofkisspeptin/GPR54signalingpathwayinthepathogenesisofprecocious puberty based on female precocious puberty rat model induced by the single dose of danazol .METHODS:Female SD rats aged 3 d were randomly divided into normal group , vehicle group and model group .On the 5th day, the model rats were given a single subcutaneous injection of danazol with ethanol and ethylene glycol mixture .All rats were executed on 15 d, 25 d, 30 d, 35 d and 40 d, and the samples were collected to observe the sexual organ development .The levels of E2 , FSH and LH in peripheral blood were measured by ELISA .The Kiss-1 mRNA expression of Kiss-1, GPR54 and GnRH in hypothalamus was detected by real-time PCR.The kisspeptin expression in rat hypothalamus was observed by immunofluo-rescence .RESULTS:The time for puberty onset and sexual maturation in the model rats was significantly earlier than that in normal group and vehicle group .On days 25 and 30, the levels of peripheral sex hormones and uterine coefficients in model group were significantly higher than those in normal group and vehicle group .On days 25 and 30, the ovarian mor-phological development in the model rats was significantly earlier than that in normal group .On day 25, the mRNA expres-sion of hypothalamic Kiss-1 and GnRH, and kisspeptin expression of hypothalamic arcuate nucleus in the model rats signifi -cantly increased compared with normal group and vehicle group .On day 30, kisspeptin expression of hypothalamic arcuate nucleus in the model rats decreased compared with normal group and vehicle group .On day 35, the mRNA expression of Kiss-1 and GnRH in the model rats decreased compared with normal group and vehicle group .The mRNA expression of GPR54 had no obvious difference among all groups .CONCLUSION:The Kiss-1 mRNA and kisspeptin expression in the model rats with precocious puberty is significantly increased in the hypothalamus during onset of puberty , suggesting that kisspeptin is an initiating factor for precocious puberty .Kisspeptin/GPR54 signaling pathway may play an important role in the occurrence of precocious puberty .

GnIH/GPR147 and Kisspeptin/GPR54 in puberty onset / 国际儿科学杂志

The initiation of puberty is associated with the hypothalamus-pituitary-gonadal( HPG) axis. The activation of gonadotropin-releasing hormone( GnRH) is the key factor in the initiation of puberty. The initi-ation of puberty is a complicated process,GnRH is under the influence of many associated neuropeptides. Re-cently,the studies have found that GnIH and Kisspeptin can respectively inhibit and promote the hypothalamus GnRH secretion of mammals,indicating that GnIH and Kisspeptin on regulation of reproductive endocrine axis play very important roles. Therefore,GnIH/GPR147 and Kisspeptin/GPR54 pathways may be closely associated with the initiation of puberty.