Hypothalamic miR-30 regulates puberty onset via repression of the puberty-suppressing factor, Mkrn3.

Mkrn3, the maternally imprinted gene encoding the makorin RING-finger protein-3, has recently emerged as putative pubertal repressor, as evidenced by central precocity caused by MKRN3 mutations in humans; yet, the molecular underpinnings of this key regulatory action remain largely unexplored. We report herein that the microRNA, miR-30, with three binding sites in a highly conserved region of its 3' UTR, operates as repressor of Mkrn3 to control pubertal onset. Hypothalamic miR-30b expression increased, while Mkrn3 mRNA and protein content decreased, during rat postnatal maturation. Neonatal estrogen exposure, causing pubertal alterations, enhanced hypothalamic Mkrn3 and suppressed miR-30b expression in female rats. Functional in vitro analyses demonstrated a strong repressive action of miR-30b on Mkrn3 3' UTR. Moreover, central infusion during the juvenile period of target site blockers, tailored to prevent miR-30 binding to Mkrn3 3' UTR, reversed the prepubertal down-regulation of hypothalamic Mkrn3 protein and delayed female puberty. Collectively, our data unveil a novel hypothalamic miRNA pathway, involving miR-30, with a prominent role in the control of puberty via Mkrn3 repression. These findings expand our current understanding of the molecular basis of puberty and its disease states.

Long-Term Outcomes of Patients with Central Precocious Puberty due to Hypothalamic Hamartoma after GnRHa Treatment: Anthropometric, Metabolic, and Reproductive Aspects.

BACKGROUND: Hypothalamic hamartoma (HH) represents the commonest cause of organic central precocious puberty (CPP). Follow-up of these patients in adulthood is scarce. OBJECTIVE: To describe the anthropometric, metabolic, and reproductive parameters of patients with CPP due to HH before and after treatment with gonadotropin-releasing hormone analog (GnRHa). METHODS: We performed a retrospective and cross-sectional study in a single tertiary center including 14 patients (7 females) with CPP due to HH. RESULTS: The mean duration of GnRHa treatment was 7.7 ± 2.4 years in boys and 7.9 ± 2.1 years in girls. GnRHa treatment was interrupted at the mean chronological age (CA) of 12.1 ± 1.1 years in boys and 10.7 ± 0.5 years in girls. At the last visit, the mean CA of the male and female patients was 21.5 ± 3.2 and 24 ± 3.9 years, respectively. Eleven of the 14 patients reached normal final height (FH) (standard deviation score -0.6 ± 0.9 for males and -0.6 ± 0.5 for females), all of them within the target height (TH) range. The remaining 3 patients had predicted height within the TH range. The mean body mass index and the percentage of body fat mass was significantly higher in females, with a higher prevalence of metabolic disorders. All patients presented normal gonadal function in adulthood, and 3 males fathered a child. CONCLUSION: All patients with CPP due to HH reached normal FH or near-FH. A higher prevalence of overweight/obesity and hypercholesterolemia was observed in the female patients. Finally, no reproductive disorder was identified in both sexes, indicating that HH per se has no deleterious effect on the gonadotropic axis in adulthood.

Altered expression of noncanonical Wnt pathway genes in paediatric and adult adrenocortical tumours.

CONTEXT: The role of planar cell polarity (Wnt/PCP) and calcium-dependent (Wnt/Ca) noncanonical Wnt pathways in adrenocortical tumours (ACTs) is unknown. OBJECTIVES: To investigate the gene expression of Wnt/PCP and Wnt/Ca pathways and its association with TP53 p.R337H and CTNNB1 mutations in paediatric and adult ACTs and to correlate these findings with clinical outcome. PATIENTS: Expression of noncanonical Wnt-related genes was evaluated in 91 ACTs (66 children and 25 adults) by qPCR and the expression of beta-catenin, P53 and protein effectors of Wnt/Ca (NFAT) and Wnt/PCP (JNK) by immunohistochemistry. TP53 and CTNNB1 genes were sequenced. RESULTS: TP53 p.R337H mutation frequency was higher in children (86% vs 28%), while CTNNB1 mutation was higher in adults (32% vs 6%). Mortality was higher in adults harbouring TP53 p.R337H and in children with CTNNB1 mutations. Overexpression of WNT5A, Wnt/Ca ligand, was observed in children and adults. Overexpression of MAPK8 and underexpression of PRICKLE, Wnt/PCP mediators, were observed in paediatric but not in adult cases. Cytoplasmic/nuclear beta-catenin and P53 accumulation was observed in the majority of paediatric and adult ACTs as well as NFAT and JNK. Overexpression of MAPK8 and underexpression of PRICKLE were associated with mortality in children, while overexpression of WNT5A and underexpression of PRICKLE were associated with mortality in adults. CONCLUSIONS: In our study, TP53 p.R337H and CTNNB1 mutations correlated with poor prognosis in adults and children, respectively. We demonstrate, for the first time, the activation of Wnt/PCP and Wnt/Ca noncanonical pathway genes, and their association with poor outcome in children and adults, suggesting their putative involvement in ACTs aggressiveness.

Progression to adrenocortical tumorigenesis in mice and humans through insulin-like growth factor 2 and ß-catenin.

Dysregulation of the WNT and insulin-like growth factor 2 (IGF2) signaling pathways has been implicated in sporadic and syndromic forms of adrenocortical carcinoma (ACC). Abnormal ß-catenin staining and CTNNB1 mutations are reported to be common in both adrenocortical adenoma and ACC, whereas elevated IGF2 expression is associated primarily with ACC. To better understand the contribution of these pathways in the tumorigenesis of ACC, we examined clinicopathological and molecular data and used mouse models. Evaluation of adrenal tumors from 118 adult patients demonstrated an increase in CTNNB1 mutations and abnormal ß-catenin accumulation in both adrenocortical adenoma and ACC. In ACC, these features were adversely associated with survival. Mice with stabilized ß-catenin exhibited a temporal progression of increased adrenocortical hyperplasia, with subsequent microscopic and macroscopic adenoma formation. Elevated Igf2 expression alone did not cause hyperplasia. With the combination of stabilized ß-catenin and elevated Igf2 expression, adrenal glands were larger, displayed earlier onset of hyperplasia, and developed more frequent macroscopic adenomas (as well as one carcinoma). Our results are consistent with a model in which dysregulation of one pathway may result in adrenal hyperplasia, but accumulation of a second or multiple alterations is necessary for tumorigenesis.

Molecular basis of normal and pathological puberty: from basic mechanisms to clinical implications.

Puberty is a major maturational event; its mechanisms and timing are driven by genetic determinants, but also controlled by endogenous and environmental cues. Substantial progress towards elucidation of the neuroendocrine networks governing puberty has taken place. However, key aspects of the mechanisms responsible for the precise timing of puberty and its alterations have only recently begun to be deciphered, propelled by epidemiological data suggesting that pubertal timing is changing in humans, via mechanisms that are not yet understood. By integrating basic and clinical data, we provide a comprehensive overview of current advances on the physiological basis of puberty, with a particular focus on the roles of kisspeptins and other central transmitters, the underlying molecular and endocrine mechanisms, and the pathways involved in pubertal modulation by nutritional and metabolic cues. Additionally, we have summarised molecular features of precocious and delayed puberty in both sexes, as revealed by clinical and genetic studies. This Review is a synoptic up-to-date view of how puberty is controlled and of the pathogenesis of major pubertal alterations, from both a clinical and translational perspective. We also highlight unsolved challenges that will seemingly concentrate future research efforts in this active domain of endocrinology.

Prevalence of Deleterious Variants in MC3R in Patients With Constitutional Delay of Growth and Puberty.

CONTEXT: The melanocortin 3 receptor (MC3R) has recently emerged as a critical regulator of pubertal timing, linear growth, and the acquisition of lean mass in humans and mice. In population-based studies, heterozygous carriers of deleterious variants in MC3R report a later onset of puberty than noncarriers. However, the frequency of such variants in patients who present with clinical disorders of pubertal development is currently unknown. OBJECTIVE: This work aimed to determine whether deleterious MC3R variants are more frequently found in patients clinically presenting with constitutional delay of growth and puberty (CDGP) or normosmic idiopathic hypogonadotropic hypogonadism (nIHH). METHODS: We examined the sequence of MC3R in 362 adolescents with a clinical diagnosis of CDGP and 657 patients with nIHH, experimentally characterized the signaling properties of all nonsynonymous variants found and compared their frequency to that in 5774 controls from a population-based cohort. Additionally, we established the relative frequency of predicted deleterious variants in individuals with self-reported delayed vs normally timed menarche/voice-breaking in the UK Biobank cohort. RESULTS: MC3R loss-of-function variants were infrequent but overrepresented in patients with CDGP (8/362 [2.2%]; OR = 4.17; P = .001). There was no strong evidence of overrepresentation in patients with nIHH (4/657 [0.6%]; OR = 1.15; P = .779). In 246 328 women from the UK Biobank, predicted deleterious variants were more frequently found in those self-reporting delayed (aged ≥16 years) vs normal age at menarche (OR = 1.66; P = 3.90E-07). CONCLUSION: We have found evidence that functionally damaging variants in MC3R are overrepresented in individuals with CDGP but are not a common cause of this phenotype.

Precocious sexual maturation: Unravelling the mechanisms of pubertal onset through clinical observations.

Puberty is a crucial biological process normally occurring at a specific time during the lifespan, during which sexual and somatic maturation are completed, and reproductive capacity is reached. Pubertal timing is not only determined by genetics, but also by endogenous and environmental cues, including nutritional and metabolic signals. During the last decade, we have learned much regarding the essential roles of kisspeptins and the neuropeptide pathways that converge on these neurones to modulate kisspeptin signalling, as well as neurokinin B and dynorphin, the co-transmitters of Kiss1 neurones in the arcuate nucleus, and the effects of melanocortins on puberty. Indeed, melanocortins are involved in transmitting the regulatory actions of metabolic cues on pubertal maturation. Intracellular metabolic sensors, such as the AMP-activated protein kinase and the fuel-sensing deacetylase SIRT1, have been shown to contribute to puberty. Further understanding of these signals and regulatory circuits will help uncover the intimacies of the central control of puberty, as well as how alterations in metabolic status, ranging from undernutrition to obesity, affect the pubertal process. Precocious puberty is rare and has a clear female predominance. Central precocious puberty (CPP) is diagnosed when premature activation of the hypothalamic-pituitary axis occurs. Its causes are heterogeneous, with alterations of the central nervous system being of special interest, and with environmental factors also playing a role in some cases. During the last decade, several mutations in different genes (including KISS1, KISS1R, MKRN3 and DLK1) that cause CPP have been discovered. Loss-of-function mutations in MKRN3 are the most common monogenic cause of CPP known to date. Here, we review and update what is known regarding the genotype-phenotype relationship in patients with CPP.

Anthropometric, metabolic, and reproductive outcomes of patients with central precocious puberty treated with leuprorelin acetate 3-month depot (11.25 mg).

OBJECTIVES: Longer-acting gonadotropin-releasing hormone analogs (GnRHa) have been widely used for central precocious puberty (CPP) treatment. However, the follow-up of patients after this treatment are still scarce. Our aim was to describe anthropometric, metabolic, and reproductive follow-up of CPP patients after treatment with leuprorelin acetate 3-month depot (11.25 mg). METHODS: Twenty-two female patients with idiopathic CPP were treated with leuprorelin acetate 3-month depot (11.25 mg). Their medical records were retrospectively evaluated regarding clinical, hormonal, and imaging aspects before, during, and after GnRHa treatment until adult height (AH). RESULTS: At the diagnosis of CPP, the mean chronological age (CA) was 8.2 ± 1.13 year, and mean bone age (BA) was 10.4 ± 1.4 year. Mean height SDS at the start and the end of GnRHa treatment was 1.6 ± 0.8 and 1.3 ± 0.9, respectively. The mean duration of GnRHa treatment was 2.8 ± 0.8 year. Mean predicted adult heights (PAH) at the start and the end of GnRH treatment was 153.2 ± 8.6 and 164.4 ± 7.3 cm, respectively (p<0.05). The mean AH was 163.2 ± 6.2 cm (mean SDS: 0.1 ± 1). All patients were within their target height (TH) range. There was a decrease in the percentage of overweight and obesity from the diagnosis until AH (39-19% p>0.05). At the AH, the insulin resistance and high LDL levels were identified in 3/17 patients (17.6%) and 2/21 patients (9.5%), respectively. The mean CA of menarche was 12.2 ± 0.5 years. At the AH, PCOS was diagnosed in one patient (4.8%). CONCLUSIONS: Long-term anthropometric, metabolic, and reproductive follow-up of patients with CPP treated with longer-acting GnRHa revealed effectivity, safety, and favorable outcomes.

Transcriptomic Response to 1,25-Dihydroxyvitamin D in Human Fibroblasts with or without a Functional Vitamin D Receptor (VDR): Novel Target Genes and Insights into VDR Basal Transcriptional Activity.

The vitamin D receptor (VDR) mediates vitamin D actions beyond bone health. While VDR activation by 1,25-dihydroxyvitamin D (1,25D) leads to robust transcriptional regulation, less is known about VDR actions in the absence of 1,25D. We analyzed the transcriptomic response to 1,25D in fibroblasts bearing a severe homozygous hereditary vitamin D resistant rickets-related p.Arg30* VDR mutation (MUT) and in control fibroblasts (CO). Roughly 4.5% of the transcriptome was regulated by 1,25D in CO fibroblasts, while MUT cells without a functional VDR were insensitive to 1,25D. Novel VDR target genes identified in human fibroblasts included bone and cartilage factors CILP, EFNB2, and GALNT12. Vehicle-treated CO and MUT fibroblasts had strikingly different transcriptomes, suggesting basal VDR activity. Indeed, oppositional transcriptional effects in basal conditions versus after 1,25D activation were implied for a subset of target genes mostly involved with cell cycle. Cell proliferation assays corroborated this conjectured oppositional basal VDR activity, indicating that precise 1,25D dosage in target tissues might be essential for modulating vitamin D actions in human health.