Dataset Information

MKRN3 inhibits the reproductive axis through actions in kisspeptin-expressing neurons.

ABSTRACT: The identification of loss-of-function mutations in MKRN3 in patients with central precocious puberty in association with the decrease in MKRN3 expression in the medial basal hypothalamus of mice before the initiation of reproductive maturation suggests that MKRN3 is acting as a brake on gonadotropin-releasing hormone (GnRH) secretion during childhood. In the current study, we investigated the mechanism by which MKRN3 prevents premature manifestation of the pubertal process. We showed that, as in mice, MKRN3 expression is high in the hypothalamus of rats and nonhuman primates early in life, decreases as puberty approaches, and is independent of sex steroid hormones. We demonstrated that Mkrn3 is expressed in Kiss1 neurons of the mouse hypothalamic arcuate nucleus and that MKRN3 repressed promoter activity of human KISS1 and TAC3, 2 key stimulators of GnRH secretion. We further showed that MKRN3 has ubiquitinase activity, that this activity is reduced by MKRN3 mutations affecting the RING finger domain, and that these mutations compromised the ability of MKRN3 to repress KISS1 and TAC3 promoter activity. These results indicate that MKRN3 acts to prevent puberty initiation, at least in part, by repressing KISS1 and TAC3 transcription and that this action may involve an MKRN3-directed ubiquitination-mediated mechanism.

SUBMITTER: Abreu AP

PROVIDER: S-EPMC7410046 | biostudies-literature | 2020 Aug

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

MKRN3 inhibits the reproductive axis through actions in kisspeptin-expressing neurons.

Abreu Ana Paula AP Toro Carlos A CA Song Yong Bhum YB Navarro Victor M VM Bosch Martha A MA Eren Aysegul A Liang Joy N JN Carroll Rona S RS Latronico Ana Claudia AC Rønnekleiv Oline K OK Aylwin Carlos F CF Lomniczi Alejandro A Ojeda Sergio S Kaiser Ursula B UB

The Journal of clinical investigation 20200801 8

The identification of loss-of-function mutations in MKRN3 in patients with central precocious puberty in association with the decrease in MKRN3 expression in the medial basal hypothalamus of mice before the initiation of reproductive maturation suggests that MKRN3 is acting as a brake on gonadotropin-releasing hormone (GnRH) secretion during childhood. In the current study, we investigated the mechanism by which MKRN3 prevents premature manifestation of the pubertal process. We showed that, as i ...[more]

PMID: 32407292

Similar Datasets

Project description:The kiss system is known to regulate puberty and to be involved in the onset of reproduction, acting upstream of the Brain-Pituitary-Gonad axis in gonadotrophin releasing hormone neurons and stimulating secretion of GnRH. Kisspeptin has been proven to be a novel therapeutic for fertility disorders in humans. In fish, positive results have also observed the prospective of this hormone to induce gamete development. During the last two decades, support has been obtained describing the key role of microRNAs (miRNA) in regulating gene expression at the post-transcriptional level and they have been recommended as relevant biomarkers in reproductive studies. Senegalese sole is a marine flatfish species with high importance in the European aquaculture industry, due to its good growth rate and high market value. However, this species presents a bottleneck in terms of reproduction, which does not allow to close the cycle in captive conditions. Hence, this study aimed to observe the effect of a novel hormonal treatment using kisspeptin in miRNA expression related to reproductive performance in cultured Senegalese sole breeders. For this purpose, Senegalese sole F1 broodstock were held at CCMAR facilities in 4 tanks of 3m3 (n = 12/per tank, sex ratio 1:1) under natural photoperiod and temperature conditions. During the reproductive season, the animals from each 2 of the tanks were treated either with SSkiss2_v2 decapeptide in a single intramuscular injection, or with a PBS injection for control groups. After the treatment (2 and 4 days), all fish were anesthetized and sampled for blood collection. Afterwards, plasma was obtained to determine several parameters related to reproductive physiology (Fsh, Lh and sexual esteroids (T, 11-KT and E2)) and miRNAs regulation. After observing the high implication of this treatment in the gonadotrofins, above all in Fsh and sexual esteroids, above all in T, the RNA was extracted from blood plasma using miRNeasy Serum/Plasma Kit (Qiagen, Germany) and libraries were prepared using NEXTflex Small RNA-Seq kit v3 (Bioo Scientific, USA). Small RNA sequencing (sRNA-seq) (NextSeq 500) was performed on sole treated with kisspeptin (n = 16) and non-treated control fish (n = 14). A total of 1,467 unique miRNAs were expressed in Senegalese sole plasma. A multidimensional scaling (MDS) plot showed no clear clustering of the samples with the kisspeptin treatment. However, the differential expression analysis revealed one miRNA, miR-1-3p, to be highly up-regulated in both males and females treated with kisspeptin compared to control sole. This miRNA is linked with myogenesis and angiogenesis, and skeletal muscle development in fish. Three isomirs (let 7e, miR-199a-3p, miR-100-5p) were differentially expressed between females treated and control fish. MicroRNA let-7e is an important regulator of endothelial function and inflammation, related to testosterone pathway release; miR-199a-3p plays an important role in inflammation and women fertility and miR-100-5p might be implicated in the regulation of cell growth and oocytes maturation. In conclusion, kisspeptin treatment may affect gonad maturation in females and muscle growth in males. Our data support the possibility of using circulating miRNAs as less invasive physiological biomarkers in fish reproduction.

Project description:BackgroundPerturbations in the timing of puberty, with potential adverse consequences in later health, are increasingly common. The underlying neurohormonal mechanisms are unfolded, but nutritional alterations are key contributors. Efforts to unveil the basis of normal puberty and its metabolic control have focused on mechanisms controlling expression of Kiss1, the gene encoding the puberty-activating neuropeptide, kisspeptin. However, other regulatory phenomena remain ill-defined. Here, we address the putative role of the G protein-coupled-receptor kinase-2, GRK2, in GnRH neurons, as modulator of pubertal timing via repression of the actions of kisspeptin, in normal maturation and conditions of nutritional deficiency.MethodsHypothalamic RNA and protein expression analyses were conducted in maturing female rats. Pharmacological studies involved central administration of GRK2 inhibitor, βARK1-I, and assessment of gonadotropin responses to kisspeptin or phenotypic and hormonal markers of puberty, under normal nutrition or early subnutrition in female rats. In addition, a mouse line with selective ablation of GRK2 in GnRH neurons, aka G-GRKO, was generated, in which hormonal responses to kisspeptin and puberty onset were monitored, in normal conditions and after nutritional deprivation.ResultsHypothalamic GRK2 expression increased along postnatal maturation in female rats, especially in the preoptic area, where most GnRH neurons reside, but decreased during the juvenile-to-pubertal transition. Blockade of GRK2 activity enhanced Ca+2 responses to kisspeptin in vitro, while central inhibition of GRK2 in vivo augmented gonadotropin responses to kisspeptin and advanced puberty onset. Postnatal undernutrition increased hypothalamic GRK2 expression and delayed puberty onset, the latter being partially reversed by central GRK2 inhibition. Conditional ablation of GRK2 in GnRH neurons enhanced gonadotropin responses to kisspeptin, accelerated puberty onset, and increased LH pulse frequency, while partially prevented the negative impact of subnutrition on pubertal timing and LH pulsatility in mice.ConclusionsOur data disclose a novel pathway whereby GRK2 negatively regulates kisspeptin actions in GnRH neurons, as major regulatory mechanism for tuning pubertal timing in nutritionally-compromised conditions.

Project description:Growth and reproduction are closely related. Growth hormone (GH)-transgenic common carp exhibit accelerated growth and delayed reproductive development, which provides an amenable model to study hormone cross talk between the growth and reproductive axes. We analyzed the energy status and reproductive development in GH-transgenic common carp by using multi-tissue RNA sequencing, real-time-PCR, Western blotting, ELISA, immunofluorescence, and in vitro incubation. The expression of gys (glycogen synthase) and igfbp1 (insulin-like growth factor binding protein) as well as blood glucose concentrations are lower in GH-transgenic carp. Agrp1 (agouti-related protein 1) and sla (somatolactin a), which are related to appetite and lipid catabolism, are significantly higher in GH-transgenic carp. Low glucose content and increased appetite indicate disrupted metabolic and energy deprivation status in GH-transgenic carp. Meanwhile, the expression of genes, such as gnrhr2 (gonadotropin-releasing hormone receptor 2), gthα (gonadotropin hormone, alpha polypeptide), fshβ (follicle stimulating hormone, beta polypeptide), lhβ [luteinizing hormone, beta polypeptide] in the pituitary, cyp19a1a (aromatase A) in the gonad, and cyp19a1b (aromatase B) in the hypothalamus, are decreased in GH-transgenic carp. In contrast, pituitary gnih (gonadotropin inhibitory hormone), drd1 (dopamine receptor D1), drd3 (dopamine receptor D3), and drd4 (dopamine receptor D4) exhibit increased expression, which were associated with the retarded reproductive development. Leptin receptor mRNA was detected by fluorescence in situ hybridization in the pituitary including the pars intermedia and proximal pars distalis, suggesting a direct effect of leptin on LH. Recombinant carp Leptin protein was shown to stimulate pituitary gthα, fshβ, lhβ expression, and ovarian germinal vesicle breakdown in vitro. In addition to neuroendocrine factors, we suggest that reduced hepatic leptin signaling to the pituitary might be part of the response to overexpression of GH and the resulting delay in puberty onset.

Dataset Information

MKRN3 inhibits the reproductive axis through actions in kisspeptin-expressing neurons.

Publications

MKRN3 inhibits the reproductive axis through actions in kisspeptin-expressing neurons.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets