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International Journal of Molecular... Nov 2021The growth hormone (GH)-insulin-like growth factor-1 (IGF1) endocrine axis is a central player in normal growth and metabolism as well as in a number of pathologies,...
The growth hormone (GH)-insulin-like growth factor-1 (IGF1) endocrine axis is a central player in normal growth and metabolism as well as in a number of pathologies, including cancer. The GH-IGF1 hormonal system, in addition, has emerged as a major determinant of lifespan and healthspan. Laron syndrome (LS), the best characterized entity under the spectrum of the congenital IGF1 deficiencies, results from mutation of the GH receptor (GHR) gene, leading to dwarfism, obesity and other defects. Consistent with the key role of IGF1 in cellular proliferation, epidemiological studies have shown that LS patients are protected from cancer development. While reduced expression of components of the GH-IGF1 axis is associated with enhanced longevity in animal models, it is still unknown whether LS is associated with an increased lifespan. MicroRNAs (miRs) are endogenous short non-coding RNAs that regulate the expression of complementary mRNAs. While a number of miRs involved in the regulation of IGF components have been identified, no previous studies have investigated the differential expression of miRs in congenital IGF1 deficiencies. The present study was aimed at identifying miRs that are differentially expressed in LS and that might account for the phenotypic features of LS patients, including longevity. Our genomic analyses provide evidence that miR-132-3p was highly expressed in LS. In addition, we identified SIRT1, a member of the sirtuin family of histone deacetylases, as a target for negative regulation by miR-132-3p. The data was consistent with the notion that low concentrations of IGF1 in LS lead to elevated miR-132-3p levels, with ensuing reduction in SIRT1 gene expression. The impact of the IGF1-miR-132-3p-SIRT1 loop on aging merits further investigation.
Topics: 3' Untranslated Regions; Adult; Case-Control Studies; Cell Line; Cell Proliferation; Female; Humans; Insulin-Like Growth Factor I; Laron Syndrome; Longevity; MicroRNAs; Middle Aged; Sirtuin 1; Up-Regulation
PubMed: 34769292
DOI: 10.3390/ijms222111861 -
Med (New York, N.Y.) Apr 2024Human subjects with generalized growth hormone (GH) insensitivity due to GH receptor deficiency (GHRD)/Laron syndrome display a very low incidence of insulin resistance,...
BACKGROUND
Human subjects with generalized growth hormone (GH) insensitivity due to GH receptor deficiency (GHRD)/Laron syndrome display a very low incidence of insulin resistance, diabetes, and cancer, as well as delayed age-related cognitive decline. However, the risk of cardiovascular disease (CVD) in these subjects is poorly understood. Here, we have assessed cardiovascular function, damage, and risk factors in GHRD subjects and their relatives.
METHODS
We measured markers of CVD in two phases: one in a cohort of 30 individuals (GHRD = 16, control relatives = 14) brought to USC (in Los Angeles, CA) and one in a cohort including additional individuals examined in Ecuador (where the subjects live) for a total of 44 individuals (GHRD = 21, control relatives = 23). Data were collected on GHRD and control groups living in similar geographical locations and sharing comparable environmental and socio-economic circumstances.
RESULTS
Compared to controls, GHRD subjects displayed lower serum glucose, insulin, blood pressure, smaller cardiac dimensions, similar pulse wave velocity, lower carotid artery intima-media thickness, lower creatinine, and a non-significant but major reduction in the portion of subjects with carotid atherosclerotic plaques (7% GHRDs vs. 36%, Controls p = 0.1333) despite elevated low-density lipoprotein cholesterol levels.
CONCLUSION
The current study indicates that individuals with GHRD have normal or improved levels of cardiovascular disease risk factors as compared to their relatives.
FUNDING
This study was funded in part by NIH/NIA grant P01 AG034906 to V.D.L.
PubMed: 38677286
DOI: 10.1016/j.medj.2024.03.022 -
Genes Jan 2024Richard Peto's paradox, first described in 1975 from an epidemiological perspective, established an inverse correlation between the probability of developing cancer in... (Review)
Review
Richard Peto's paradox, first described in 1975 from an epidemiological perspective, established an inverse correlation between the probability of developing cancer in multicellular organisms and the number of cells. Larger animals exhibit fewer tumors compared to smaller ones, though exceptions exist. Mice are more susceptible to cancer than humans, while elephants and whales demonstrate significantly lower cancer prevalence rates than humans. How nature and evolution have addressed the issue of cancer in the animal kingdom remains largely unexplored. In the field of medicine, much attention has been devoted to cancer-predisposing genes, as they offer avenues for intervention, including blocking, downregulating, early diagnosis, and targeted treatment. Predisposing genes also tend to manifest clinically earlier and more aggressively, making them easier to identify. However, despite significant strides in modern medicine, the role of protective genes lags behind. Identifying genes with a mild predisposing effect poses a significant challenge. Consequently, comprehending the protective function conferred by genes becomes even more elusive, and their very existence is subject to questioning. While the role of variable expressivity and penetrance defects of the same variant in a family is well-documented for many hereditary cancer syndromes, attempts to delineate the function of protective/modifier alleles have been restricted to a few instances. In this review, we endeavor to elucidate the role of protective genes observed in the animal kingdom, within certain genetic syndromes that appear to act as cancer-resistant/repressor alleles. Additionally, we explore the role of protective alleles in conditions predisposing to cancer. The ultimate goal is to discern why individuals, like Winston Churchill, managed to live up to 91 years of age, despite engaging in minimal physical activity, consuming large quantities of alcohol daily, and not abstaining from smoking.
Topics: Humans; Animals; Mice; Elephants; Alleles; Neoplastic Syndromes, Hereditary; Medicine; Cetacea
PubMed: 38255007
DOI: 10.3390/genes15010118 -
Endocrine-related Cancer Sep 2023Many clinical and experimental studies have implicated the growth hormone (GH)-insulin-like growth factor (IGF-1) axis with the progression of cancer. The...
Many clinical and experimental studies have implicated the growth hormone (GH)-insulin-like growth factor (IGF-1) axis with the progression of cancer. The epidemiological finding that patients with Laron syndrome (LS), the best-characterized disease under the spectrum of congenital IGF-1 deficiencies, do not develop cancer is of major scientific and translational relevance. The evasion of LS patients from cancer emphasizes the central role of the GH-IGF-1 system in cancer biology. To identify genes that are differentially expressed in LS and that might provide a biological foundation for cancer protection, we have recently conducted genome-wide profiling of LS patients and normal controls. Analyses were performed on immortalized lymphoblastoid cell lines derived from individual patients. Bioinformatic analyses identified a series of genes that are either over- or under-represented in LS. Differential expression was demonstrated in a number of gene families, including cell cycle, metabolic control, cytokine-cytokine receptor interaction, Jak-STAT and PI3K-AKT signaling, etc. Major differences between LS and controls were also noticed in pathways associated with cell cycle distribution, apoptosis, and autophagy. The identification of novel downstream targets of the GH-IGF-1 network highlights the biological complexity of this hormonal system and sheds light on previously unrecognized mechanistic aspects associated with GH-IGF-1 action in the cancer cell.
Topics: Humans; Growth Hormone; Human Growth Hormone; Insulin-Like Growth Factor I; Laron Syndrome; Neoplasms; Phosphatidylinositol 3-Kinases
PubMed: 37343154
DOI: 10.1530/ERC-22-0394 -
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 -
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 -
Oxford Medical Case Reports Sep 2021Laron syndrome (LS) is a rare autosomal recessive disorder characterized by dwarfism and typical facial phenotype. This report is the first to present three cases of...
Laron syndrome (LS) is a rare autosomal recessive disorder characterized by dwarfism and typical facial phenotype. This report is the first to present three cases of Laron syndrome affecting three female siblings from Syria. The index case presented at age of 8.5 years with severe short stature: low level of Insulin-like growth factor 1 (IGF-1), elevated levels of fasting and post-stimulation growth hormone (GH), consistent with the diagnosis of Laron syndrome. At the age of 9.5 years, she developed non-autoimmune subclinical hypothyroidism treated with Levothyroxine, then she developed dyslipidemia at the age of 11.3 years. Later, we identified two female siblings of the patient with Laron syndrome. Laron syndrome is a rare genetic disease, reporting of new cases of this rare syndrome must encourage pediatricians to develop high clinical suspicion if faced with patients with very short stature and typical facial features.
PubMed: 34527252
DOI: 10.1093/omcr/omab079 -
FEBS Open Bio Jul 2023Chagas disease (CD) is one of the most devasting parasitic diseases in the Americas, affecting 7-8 million people worldwide. In vitro and in vivo experiments have...
Chagas disease (CD) is one of the most devasting parasitic diseases in the Americas, affecting 7-8 million people worldwide. In vitro and in vivo experiments have demonstrated that growth hormone (GH) serum levels decrease as CD progresses. Interestingly, inactivating mutations in the GH receptor in humans result in Laron syndrome (LS), a clinical entity characterized by increased serum levels of GH and decreased insulin growth factor-1 (IGF-1). The largest cohort of LS subjects lives in the southern provinces of Ecuador. Remarkably, no clinical CD cases have been reported in these individuals despite living in highly endemic areas. In the current ex vivo study, we employed serum from GHR mice, also known as LS mice (a model of GH resistance with high GH and low IGF-1 levels), and serum from bovine GH (bGH) transgenic mice (high GH and IGF-1), to test the effect on Trypanosoma cruzi infection. We infected mouse fibroblast L-cells with T. cruzi (etiological CD infectious agent) and treated them with serum from each mouse type. Treatment with GHR serum (LS mice) significantly decreased L-cell infection by 28% compared with 48% from control wild-type mouse serum (WT). Treatment with bGH mouse serum significantly decreased infection of cells by 41% compared with 54% from WT controls. Our results suggest that high GH and low IGF-1 in blood circulation, as typically seen in LS individuals, confer partial protection against T. cruzi infection. This study is the first to report decreased T. cruzi infection using serum collected from two modified mouse lines with altered GH action (GHR and bGH).
Topics: Mice; Humans; Animals; Cattle; Insulin-Like Growth Factor I; Growth Hormone; Receptors, Somatotropin; Mice, Transgenic; Chagas Disease
PubMed: 37163287
DOI: 10.1002/2211-5463.13627 -
Endocrine Connections Aug 2021Animal studies suggest that insulin-like growth factor 1 (IGF1) may influence the function of the hypothalamus-pituitary-testicular axis, especially in childhood, but...
BACKGROUND
Animal studies suggest that insulin-like growth factor 1 (IGF1) may influence the function of the hypothalamus-pituitary-testicular axis, especially in childhood, but the evidence in humans is scanty. Laron syndrome, a human model of IGF1 deficiency, may help to solve this issue.
PURPOSE
This systematic review aims to analyze puberty onset and progression, testicular volume, gonadotropin, and total testosterone serum levels, sperm parameters and fertility, and penile length in patients with Laron syndrome.
METHODS
Specific keywords were used. All data on male patients with Laron syndrome were included.
RESULTS
Seventeen articles matched the inclusion criteria and were entered in the analysis, for a total of 125 male patients. Puberty was absent in 8.9% and delayed in 35.6% of untreated patients of pubertal age. After onset, the duration of the pubertal process was prolonged in 76.9% of untreated patients. The growth spurt was absent in 52.6% and delayed in 31.6% of untreated patients. The testicular volume was small in the two patients who did not receive any treatment. Treatment with IGF1 increased gonadotropin and testosterone serum levels in five out of five patients of pubertal age. No effect was found in four out of four patients younger than 5 years. No study reported data on sperm parameters and fertility. Micropenis occurred in 67.2% of patients.
CONCLUSION AND FUTURE PERSPECTIVES
Delayed puberty is common in patients with Laron syndrome. The growth hormone-IGF1 axis may influence the time of puberty onset. Serum levels of IGF1 should be investigated in children with delayed puberty, scarce progression of testicular growth, and/or micropenis. IGF1 levels might be measured in children with delayed puberty, poor testicular growth, and/or micropenis.
PubMed: 34319907
DOI: 10.1530/EC-21-0252 -
Growth Hormone & IGF Research :... Feb 2020The aim of this article is to present a historical review on giants and dwarves living in South America and the contribution of South America's researchers to scientific... (Review)
Review
The aim of this article is to present a historical review on giants and dwarves living in South America and the contribution of South America's researchers to scientific advances on growth hormone (GH) and human disorders related to GH excess and GH deficiency (GHD). We went back in time to investigate facts and myths stemming from countless reports of giants who lived in the Patagonia region, focusing on what is currently known about gigantism in South America. Additionally, we have reviewed the exceptional work carried out in two of the world's largest cohorts of dwarfism related to GH-IGF axis: one living in Itabaianinha, Brazil, suffering from severe GHD due to a mutation in the GHRH receptor (GHRHR) gene, and the other living in El Oro and Loja provinces of Ecuador, who are carriers of GH receptor gene mutation that causes total GH insensitivity (Laron syndrome). Importantly, we present an overview of the outstanding medical contribution of Jose Dantas de Souza Leite, a Brazilian physician that described the first cases of acromegaly, and Bernardo Alberto Houssay, an Argentine researcher graced with the Nobel Prize, who was one the first scientists to establish a link between GH and glucose metabolism.
Topics: Acromegaly; Biomedical Research; Dwarfism, Pituitary; Endocrinology; Gigantism; Growth Disorders; History, 16th Century; History, 17th Century; History, 18th Century; History, 19th Century; History, 20th Century; History, 21st Century; Humans; Laron Syndrome; Nobel Prize; South America
PubMed: 31864177
DOI: 10.1016/j.ghir.2019.11.004