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International Journal of Molecular... Feb 2021Anti-Müllerian hormone (AMH) is secreted by Sertoli or granulosa cells. Recent evidence suggests that AMH may play a role in the pathogenesis of hypogonadotropic...
Anti-Müllerian hormone (AMH) is secreted by Sertoli or granulosa cells. Recent evidence suggests that AMH may play a role in the pathogenesis of hypogonadotropic hypogonadism (HH) and that its serum levels could help to discriminate HH from delayed puberty. Moreover, the growth hormone (GH)/insulin-like growth factor 1 (IGF1) system may be involved in the function of gonadotropin-releasing hormone (GnRH) neurons, as delayed puberty is commonly found in patients with GH deficiency (GHD) or with Laron syndrome, a genetic form of GH resistance. The comprehension of the stimuli enhancing the migration and secretory activity of GnRH neurons might shed light on the causes of delay of puberty or HH. With these premises, we aimed to better clarify the role of the AMH, GH, and IGF1 on GnRH neuron migration and GnRH secretion, by taking advantage of previously established models of immature (GN11 cell line) and mature (GT1-7 cell line) GnRH neurons. Expression of Amhr, Ghr, and Igf1r genes was confirmed in both cell lines. Cells were then incubated with increasing concentrations of AMH (1.5-150 ng/mL), GH (3-1000 ng/mL), or IGF1 (1.5-150 ng/mL). All hormones were able to support GN11 cell chemomigration. AMH, GH, and IGF1 significantly stimulated GnRH secretion by GT1-7 cells after a 90-min incubation. To the best of our knowledge, this is the first study investigating the direct effects of GH and IGF1 in GnRH neuron migration and of GH in the GnRH secreting pattern. Taken together with previous basic and clinical studies, these findings may provide explanatory mechanisms for data, suggesting that AMH and the GH-IGF1 system play a role in HH or the onset of puberty.
Topics: Animals; Anti-Mullerian Hormone; Cell Movement; Cells, Cultured; Gonadotropin-Releasing Hormone; Human Growth Hormone; Insulin-Like Growth Factor I; Mice; Neurons
PubMed: 33671044
DOI: 10.3390/ijms22052445 -
European Journal of Endocrinology Feb 2021The European Increlex® Growth Forum Database Registry monitors the effectiveness and safety of recombinant human insulin-like growth factor-1 (rhIGF1; mecasermin,... (Observational Study)
Observational Study
OBJECTIVE
The European Increlex® Growth Forum Database Registry monitors the effectiveness and safety of recombinant human insulin-like growth factor-1 (rhIGF1; mecasermin, Increlex®) therapy in patients with severe primary IGF1 deficiency (SPIGFD). We present data from patients with and without a reported genetic diagnosis of Laron syndrome (LS).
DESIGN
Ongoing, open-label, observational registry (NCT00903110).
METHODS
Children and adolescents receiving rhIGF1 therapy from 10 European countries were enrolled in 2008-2017 (n = 242). The treatment-naïve/prepubertal (NPP) cohort (n = 138) was divided into subgroups based on reported genetic diagnosis of LS (n = 21) or non-LS (n = 117). Multivariate analysis of the NPP-non-LS subgroup was conducted to identify factors predictive of growth response (first-year-height standard deviation score (SDS) gain ≥ 0.3). Assessments included change in height and weight over 5 years and adverse events (AEs).
RESULTS
Height SDS gain from baseline was greater in the NPP-LS than the NPP-non-LS subgroup after 1 years' treatment (P < 0.05). In the NPP-non-LS subgroup, 56% were responders; young age at baseline was a positive independent predictive factor (P < 0.001). NPP-non-LS-responders and the NPP-LS subgroup had a similar mean age (6.07 years vs 7.00 years) at baseline and height SDS gain in year 1 (0.64 vs 0.70), although NPP-non-LS-responders were taller (P < 0.001) at baseline. BMI SDS changes did not differ across subgroups. Treatment-emergent AEs were experienced by 65.3% of patients; hypoglycaemia was most common.
CONCLUSIONS
In most NPP children with SPIGFD, with or without LS, rhIGF1 therapy promotes linear growth. The safety profile was consistent with previous studies.
Topics: Adolescent; Body Height; Body Weight; Child; Female; Growth; Growth Disorders; Hearing Loss, Sensorineural; Humans; Hypoglycemia; Insulin-Like Growth Factor I; Laron Syndrome; Longitudinal Studies; Male; Patient Safety; Puberty; Recombinant Proteins; Treatment Outcome; Young Adult
PubMed: 33434161
DOI: 10.1530/EJE-20-0325 -
Cells Nov 2020Laron syndrome (LS) is a rare genetic endocrinopathy that results from mutation of the growth hormone receptor () gene and is typically associated with dwarfism and... (Review)
Review
Laron syndrome (LS) is a rare genetic endocrinopathy that results from mutation of the growth hormone receptor () gene and is typically associated with dwarfism and obesity. LS is the best characterized entity under the spectrum of the congenital insulin-like growth factor-1 (IGF1) deficiencies. Epidemiological analyses have shown that LS patients do not develop cancer, whereas heterozygous family members have a cancer prevalence similar to the general population. To identify genes and signaling pathways differentially represented in LS that may help delineate a biochemical and molecular basis for cancer protection, we have recently conducted a genome-wide profiling of LS patients. Studies were based on our collection of Epstein-Barr virus (EBV)-immortalized lymphoblastoid cell lines derived from LS patients, relatives and healthy controls. Bioinformatic analyses identified differences in gene expression in several pathways, including apoptosis, metabolic control, cytokine biology, Jak-STAT and PI3K-AKT signaling, etc. Genes involved in the control of cell cycle, motility, growth and oncogenic transformation are, in general, down-regulated in LS. These genetic events seem to have a major impact on the biological properties of LS cells, including proliferation, apoptosis, response to oxidative stress, etc. Furthermore, genomic analyses allowed us to identify novel IGF1 downstream target genes that have not been previously linked to the IGF1 signaling pathway. In summary, by '' genomic data from LS patients, we were able to generate clinically-relevant information in oncology and, potentially, related disciplines.
Topics: Animals; Biomedical Research; Humans; Insulin-Like Growth Factor I; Intercellular Signaling Peptides and Proteins; Laron Syndrome; Neoplasms; Risk Factors
PubMed: 33182502
DOI: 10.3390/cells9112446 -
European Journal of Cancer (Oxford,... Dec 2020The growth hormone (GH)-insulin-like growth factor-1 (IGF1) endocrine axis has a key role in normal growth and development. Laron syndrome (LS) is a type of dwarfism...
INTRODUCTION
The growth hormone (GH)-insulin-like growth factor-1 (IGF1) endocrine axis has a key role in normal growth and development. Laron syndrome (LS) is a type of dwarfism that results from mutation of the GH receptor, leading to congenital IGF1 deficiency. Epidemiological studies have shown that LS patients are protected from cancer. Genome-wide profiling led to the identification of a series of metabolic genes whose differential expression in LS might be linked to cancer protection. Nephronectin (NPNT) is an intracellular and secreted extracellular matrix protein with important roles in kidney development. NPNT was identified as the top-downregulated gene in LS-derived cells in comparison with ethnic-, age- and gender-matched controls (p-value = 0.0148; fold-change = -3.12 versus controls). NPNT has not been previously linked to the IGF1 signaling pathway. The present study was aimed at evaluating the hypothesis that NPNT is a new target for IGF1 action and that decreased expression of NPNT in LS is correlated with cancer protection.
METHODS
Basal and IGF1-stimulated NPNT expression were assessed in LS lymphoblastoid cells as well as in human breast and prostate cancer cells. NPNT silencing experiments were conducted using siRNA methodology.
RESULTS
We provide evidence that IGF1 stimulates NPNT expression in LS-derived lymphoblastoids and various cancer cell lines. In addition, we demonstrate that NPNT silencing results in diminished activation of the AKT and ERK1/2 pathways, with ensuing decreases in cellular proliferation.
CONCLUSIONS
Our data identified the NPNT gene as a target for IGF1 action. The clinical implications of the functional and physical interactions between NPNT and the IGF1 pathway merit further investigation.
Topics: Cell Line, Tumor; Cell Proliferation; Extracellular Matrix Proteins; Humans; Insulin-Like Growth Factor I; Laron Syndrome; Neoplasms; Signal Transduction
PubMed: 33130549
DOI: 10.1016/j.ejca.2020.09.034 -
The Indian Journal of Medical Research Nov 2020
Topics: Anemia, Aplastic; Fanconi Anemia; Humans; Laron Syndrome
PubMed: 35345205
DOI: 10.4103/ijmr.IJMR_2317_19 -
Xenotransplantation Mar 2021Xenotransplantation research has made considerable progress in recent years, largely through the increasing availability of pigs with multiple genetic modifications,... (Review)
Review
Xenotransplantation research has made considerable progress in recent years, largely through the increasing availability of pigs with multiple genetic modifications, effective immunosuppressive therapy, and anti-inflammatory therapy to protect pig tissues from the primate immune and inflammatory responses and correct molecular incompatibilities. Further study is required regarding identification and investigation of physiological incompatibilities. Although the exact cause remains uncertain, we and others have observed relatively rapid growth of kidney xenografts after transplantation into nonhuman primates (NHPs). There has also been some evidence of growth, or at least ventricular hypertrophy, of the pig heart after orthotopic transplantation into NHPs. Rapid growth could be problematic, particularly with regard to the heart within the relatively restricted confines of the chest. It has been suggested that the problem of rapid growth of the pig organ after transplantation could be resolved by growth hormone receptor (GHR) gene knockout in the pig. The GHR, although most well-known for regulating growth, has many other biological functions, including regulating metabolism and controlling physiological processes. Genetically modified GHRKO pigs have recently become available. We provide data on their growth compared to comparable pigs that do not include GHRKO, and we have reviewed the literature regarding the effect of GHRKO, and its relevance to xenotransplantation.
Topics: Animals; Animals, Genetically Modified; Graft Rejection; Heterografts; Receptors, Somatotropin; Swine; Transplantation, Heterologous; Transplants
PubMed: 33058285
DOI: 10.1111/xen.12652 -
Reviews in Endocrine & Metabolic... Mar 2021The Ecuadorian cohort of subjects with LS has taught us valuable lessons since the late 80's. We have learned about migration of Sephardic Jews to our country, their... (Review)
Review
The Ecuadorian cohort of subjects with LS has taught us valuable lessons since the late 80's. We have learned about migration of Sephardic Jews to our country, their isolation in remote hamlets and further inbreeding. These geographical, historical and social determinants induced dissemination of a growth hormone (GH) receptor mutation which widely occurred in those almost inaccessible villages. Consequently, the world's largest Laron syndrome (LS) cohort emerged in Loja and El Oro, two of the southern provinces of Ecuador. We have been fortunate to study these patients since 1987. New clinical features derived from GH insensitivity, their growth patterns as well as treatment with exogenous insulin-like growth factor I (IGF-I) have been reported. Novel biochemical characteristics in the field of GH insensitivity, IGFs, IGF binding proteins (BP) and their clinical correlates have also been described. In the last few years, studies on the morbidity and mortality of Ecuadorian LS adults surprisingly demonstrated that despite obesity, they had lower incidence of diabetes and cancer than their relatives. These events were linked to their metabolic phenotype of elevated but ineffective GH concentrations and low circulating IGF-I and IGFBP-3. It was also noted that absent GH counter-regulation induces a decrease in insulin resistance (IR), which results in low but highly efficient insulin levels which properly handle metabolic substrates. We propose that the combination of low IGF-I signaling, decreased IR, and efficient serum insulin concentrations are reasonable explanations for the diminished incidence of diabetes and cancer in these subjects.
Topics: Ecuador; Humans; Insulin-Like Growth Factor Binding Proteins; Insulin-Like Growth Factor I; Laron Syndrome; Phenotype; Receptors, Somatotropin
PubMed: 33047268
DOI: 10.1007/s11154-020-09602-4 -
Reviews in Endocrine & Metabolic... Mar 2021Growth hormone (GH) induces pleiotropic effects on growth and metabolism via binding and subsequent activation of the growth hormone receptor (GHR) and its downstream... (Review)
Review
Growth hormone (GH) induces pleiotropic effects on growth and metabolism via binding and subsequent activation of the growth hormone receptor (GHR) and its downstream signaling pathways. Growth hormone insensitivity (GHI) describes a group of disorders in which there is resistance to the action of GH and resultant insulin-like growth factor I (IGF-I) deficiency. GHI is commonly due to genetic disorders of the GH receptor causing GH receptor deficiency (e.g. Laron Syndrome (LS)), decreased activation of GHR, or defects in post-receptor signaling molecules. Genetically altered mouse lines have been invaluable to better understand the physiological impact of GHI due to the ability to do invasive and longitudinal measures of metabolism, growth, and health on a whole animal or in individual tissues/cells. In the current review, the phenotype of mouse lines with GHI will be reviewed. Mouse lines to be discussed include: 1) GHR-/- mice with a gene disruption in the GHR that results in no functional GHR throughout life, also referred to as the Laron mouse, 2) mice with temporal loss of GHR (aGHRKO) starting at 6 weeks of age, 3) mice transgenic for a GHR antagonist (GHA mice), 4) mice with GHI in select tissues or cells generated via Cre-lox or related technology, and 5) assorted mice with defects in post-receptor signaling molecules. Collectively, these mouse lines have revealed an intriguing role of GH action in health, disease, and aging.
Topics: Animals; Growth Disorders; Growth Hormone; Human Growth Hormone; Humans; Insulin-Like Growth Factor I; Laron Syndrome; Mice; Receptors, Somatotropin
PubMed: 33037595
DOI: 10.1007/s11154-020-09600-6 -
Reviews in Endocrine & Metabolic... Mar 2021Growth hormone insensitivity (GHI) syndrome, first described in 1966, is classically associated with monogenic defects in the GH receptor (GHR) gene which result in... (Review)
Review
Growth hormone insensitivity (GHI) syndrome, first described in 1966, is classically associated with monogenic defects in the GH receptor (GHR) gene which result in severe post-natal growth failure as consequences of insulin-like growth factor I (IGF-I) deficiency. Over the years, recognition of other monogenic defects downstream of GHR has greatly expanded understanding of primary causes of GHI and growth retardation, with either IGF-I deficiency or IGF-I insensitivity as clinical outcomes. Mutations in IGF1 and signaling component STAT5B disrupt IGF-I production, while defects in IGFALS and PAPPA2, disrupt transport and release of circulating IGF-I, respectively, affecting bioavailability of the growth-promoting IGF-I. Defects in IGF1R, cognate cell-surface receptor for IGF-I, disrupt not only IGF-I actions, but actions of the related IGF-II peptides. The importance of IGF-II for normal developmental growth is emphasized with recent identification of defects in the maternally imprinted IGF2 gene. Current application of next-generation genomic sequencing has expedited the pace of identifying new molecular defects in known genes or in new genes, thereby expanding the spectrum of GH and IGF insensitivity. This review discusses insights gained and future directions from patient-based molecular and functional studies.
Topics: Abnormalities, Multiple; Growth Disorders; Growth Hormone; Human Growth Hormone; Humans; Insulin-Like Growth Factor I; Laron Syndrome; Mutation
PubMed: 33029712
DOI: 10.1007/s11154-020-09603-3 -
Reviews in Endocrine & Metabolic... Mar 2021Laron Syndrome (LS) [OMIm#262500], or primary GH insensitivity, was first described in 1966 in consanguineous Jewish families from Yemen. LS is characterized by a... (Review)
Review
Laron Syndrome (LS) [OMIm#262500], or primary GH insensitivity, was first described in 1966 in consanguineous Jewish families from Yemen. LS is characterized by a typical phenotype that includes dwarfism, obesity and hypogenitalism. The disease is caused by deletions or mutations of the GH-receptor gene, causing high serum GH and low IGF-I serum levels. We studied 75 patients from childhood to adult age. After early hypoglycemia due to the progressive obesity, patients tend to develop glucose intolerance and diabetes. The treatment is by recombinant IGF-I, which improves the height and restores some of the metabolic parameters. An unexpected finding was that patients homozygous for GH-R defects are protected from malignancy lifelong, not so heterozygotes or double heterozygote subjects. We estimate that there are at least 500 patients worldwide, unfortunately only few treated.
Topics: Adult; Child; Growth Hormone; Humans; Insulin-Like Growth Factor I; Laron Syndrome; Mutation; Neoplasms; Obesity; Receptors, Somatotropin
PubMed: 32964395
DOI: 10.1007/s11154-020-09595-0