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Baxter RC. Endocrine and cellular physiology and pathology of the insulin-like growth factor acid-labile subunit. Nat Rev Endocrinol 2024; 20:414-425. [PMID: 38514815 DOI: 10.1038/s41574-024-00970-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/26/2024] [Indexed: 03/23/2024]
Abstract
The acid-labile subunit (ALS) of the insulin-like growth factor (IGF) binding protein (IGFBP) complex, encoded in humans by IGFALS, has a vital role in regulating the endocrine transport and bioavailability of IGF-1 and IGF-2. Accordingly, ALS has a considerable influence on postnatal growth and metabolism. ALS is a leucine-rich glycoprotein that forms high-affinity ternary complexes with IGFBP-3 or IGFBP-5 when they are occupied by either IGF-1 or IGF-2. These complexes constitute a stable reservoir of circulating IGFs, blocking the potentially hypoglycaemic activity of unbound IGFs. ALS is primarily synthesized by hepatocytes and its expression is lower in non-hepatic tissues. ALS synthesis is strongly induced by growth hormone and suppressed by IL-1β, thus potentially serving as a marker of growth hormone secretion and/or activity and of inflammation. IGFALS mutations in humans and Igfals deletion in mice cause modest growth retardation and pubertal delay, accompanied by decreased osteogenesis and enhanced adipogenesis. In hepatocellular carcinoma, IGFALS is described as a tumour suppressor; however, its contribution to other cancers is not well delineated. This Review addresses the endocrine physiology and pathology of ALS, discusses the latest cell and proteomic studies that suggest emerging cellular roles for ALS and outlines its involvement in other disease states.
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Affiliation(s)
- Robert C Baxter
- University of Sydney, Kolling Institute, Royal North Shore Hospital, St Leonards, New South Wales, Australia.
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2
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Webster AK, Chitrakar R, Powell M, Chen J, Fisher K, Tanny RE, Stevens L, Evans K, Wei A, Antoshechkin I, Andersen EC, Baugh LR. Using population selection and sequencing to characterize natural variation of starvation resistance in C. elegans. eLife 2022; 11:80204. [PMID: 35727141 PMCID: PMC9262388 DOI: 10.7554/elife.80204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 06/20/2022] [Indexed: 11/13/2022] Open
Abstract
Starvation resistance is important to disease and fitness, but the genetic basis of its natural variation is unknown. Uncovering the genetic basis of complex, quantitative traits such as starvation resistance is technically challenging. We developed a synthetic-population (re)sequencing approach using molecular inversion probes (MIP-seq) to measure relative fitness during and after larval starvation in C. elegans. We applied this competitive assay to 100 genetically diverse, sequenced, wild strains, revealing natural variation in starvation resistance. We confirmed that the most starvation-resistant strains survive and recover from starvation better than the most starvation-sensitive strains using standard assays. We performed genome-wide association (GWA) with the MIP-seq trait data and identified three quantitative trait loci (QTL) for starvation resistance, and we created near isogenic lines (NILs) to validate the effect of these QTL on the trait. These QTL contain numerous candidate genes including several members of the Insulin/EGF Receptor-L Domain (irld) family. We used genome editing to show that four different irld genes have modest effects on starvation resistance. Natural variants of irld-39 and irld-52 affect starvation resistance, and increased resistance of the irld-39; irld-52 double mutant depends on daf-16/FoxO. DAF-16/FoxO is a widely conserved transcriptional effector of insulin/IGF signaling (IIS), and these results suggest that IRLD proteins modify IIS, though they may act through other mechanisms as well. This work demonstrates efficacy of using MIP-seq to dissect a complex trait and it suggests that irld genes are natural modifiers of starvation resistance in C. elegans.
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Affiliation(s)
- Amy K Webster
- Department of Biology, Duke University, Durham, United States
| | - Rojin Chitrakar
- Department of Biology, Duke University, Durham, United States
| | - Maya Powell
- Department of Biology, Duke University, Durham, United States
| | - Jingxian Chen
- Department of Biology, Duke University, Durham, United States
| | - Kinsey Fisher
- Department of Biology, Duke University, Durham, United States
| | - Robyn E Tanny
- Department of Molecular Biosciences, Northwestern University, Evanston, United States
| | - Lewis Stevens
- Department of Molecular Biosciences, Northwestern University, Evanston, United States
| | - Kathryn Evans
- Department of Molecular Biosciences, Northwestern University, Evanston, United States
| | - Angela Wei
- Department of Biology, Duke University, Durham, United States
| | - Igor Antoshechkin
- Division of Biology, California Institute of Technology, Pasadena, United States
| | - Erik C Andersen
- Department of Molecular Biosciences, Northwestern University, Evanston, United States
| | - L Ryan Baugh
- Department of Biology, Duke University, Durham, United States
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3
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IGF2: Development, Genetic and Epigenetic Abnormalities. Cells 2022; 11:cells11121886. [PMID: 35741015 PMCID: PMC9221339 DOI: 10.3390/cells11121886] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Revised: 06/04/2022] [Accepted: 06/06/2022] [Indexed: 02/07/2023] Open
Abstract
In the 30 years since the first report of parental imprinting in insulin-like growth factor 2 (Igf2) knockout mouse models, we have learnt much about the structure of this protein, its role and regulation. Indeed, many animal and human studies involving innovative techniques have shed light on the complex regulation of IGF2 expression. The physiological roles of IGF-II have also been documented, revealing pleiotropic tissue-specific and developmental-stage-dependent action. Furthermore, in recent years, animal studies have highlighted important interspecies differences in IGF-II function, gene expression and regulation. The identification of human disorders due to impaired IGF2 gene expression has also helped to elucidate the major role of IGF-II in growth and in tumor proliferation. The Silver-Russell and Beckwith-Wiedemann syndromes are the most representative imprinted disorders, as they constitute both phenotypic and molecular mirrors of IGF2-linked abnormalities. The characterization of patients with either epigenetic or genetic defects altering IGF2 expression has confirmed the central role of IGF-II in human growth regulation, particularly before birth, and its effects on broader body functions, such as metabolism or tumor susceptibility. Given the long-term health impact of these rare disorders, it is important to understand the consequences of IGF2 defects in these patients.
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Сахнова ЕЕ, Пржиялковская ЕГ, Белая ЖЕ, Мельниченко ГА. [Discordant parameters of insulin-like growth factor 1 and growth hormone in the diagnosis and monitoring of acromegaly]. PROBLEMY ENDOKRINOLOGII 2021; 68:40-48. [PMID: 35262296 PMCID: PMC9761869 DOI: 10.14341/probl12791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 12/16/2021] [Accepted: 12/16/2021] [Indexed: 01/09/2023]
Abstract
Acromegaly is a rare endocrine disorder associated with multiple complications and increased mortality. Timely diagnosis and adequate treatment can bring the life expectancy of patients with acromegaly closer to the general population level. The tests for the diagnosis of acromegaly are measurement of both serum GH, and GH after oral glucose administration; serum insulin-like growth factor-1 (IGF-1). However, in clinical practice, up to 39% of patients with discordant results are found. The patients with discordant GH and IGF-1levels, are the most difficult to manage. This review discusses the prevalence of discordant GH and IGF-1 outcomes in patients with acromegaly; factors causing this discrepancy; the impact of hormone levels on treatment outcomes. Although endocrinologists are used to dealing with this discrepancy in clinical practice for many years, discordant patients'outcome remains uncertain and undefined The optimal treatment should be individually tailored for each patient, taking into account all clinical parameters.
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Affiliation(s)
- Е. Е. Сахнова
- Национальный медицинский исследовательский центр эндокринологии
| | | | - Ж. Е. Белая
- Национальный медицинский исследовательский центр эндокринологии
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Hata S, Mori H, Yasuda T, Irie Y, Yamamoto T, Umayahara Y, Ryomoto K, Yoshiuchi K, Yoshida S, Shimomura I, Kuroda A, Matsuhisa M. A low serum IGF-1 is correlated with sarcopenia in subjects with type 1 diabetes mellitus: Findings from a post-hoc analysis of the iDIAMOND study. Diabetes Res Clin Pract 2021; 179:108998. [PMID: 34390761 DOI: 10.1016/j.diabres.2021.108998] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 08/03/2021] [Accepted: 08/06/2021] [Indexed: 01/16/2023]
Abstract
AIM Our previous study revealed that sarcopenia was frequently observed in subjects with type 1 diabetes mellitus (T1DM). However, the factors associated with sarcopenia that are related to T1DM have not yet been clarified. Insulin-like growth factor-1 (IGF-1) has been shown to play a role in skeletal muscle growth, differentiation, and regeneration. The present study, therefore, investigated the association between the serum IGF-1 level and sarcopenia and low skeletal muscle mass in subjects with T1DM. METHODS This cross-sectional study enrolled subjects with T1DM (n = 168) and without diabetes (n = 59) who had had their clinical data on serum IGF-1 collected in the iDIAMOND study. RESULTS The z-score of serum IGF-1 was significantly lower in the subjects with T1DM than that in those without diabetes (p < 0.001). Among subjects with T1DM, the z-score of serum IGF-1 was significantly lower in sarcopenic subjects than in non-sarcopenic subjects. The multivariable logistic regression analysis showed that the serum IGF-1 z-score was an independent determinant of sarcopenia and a low skeletal muscle mass index, but not low grip strength nor slow gait speed in subjects with T1DM. CONCLUSIONS A low serum IGF-1 level is correlated with sarcopenia and low skeletal muscle mass in subjects with T1DM.
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Affiliation(s)
- Sonyun Hata
- Department of Endocrinology and Metabolism, Osaka Police Hospital, Osaka, Japan
| | - Hiroyasu Mori
- Diabetes Therapeutics and Research Center, Institute of Advanced Medical Sciences, Tokushima University, Tokushima, Japan
| | - Tetsuyuki Yasuda
- Department of Endocrinology and Metabolism, Osaka Police Hospital, Osaka, Japan
| | - Yoko Irie
- Department of Endocrinology and Metabolism, Osaka Police Hospital, Osaka, Japan
| | | | | | | | | | - Sumiko Yoshida
- Department of Hematology, Endocrinology and Metabolism, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan
| | - Iichiro Shimomura
- Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Akio Kuroda
- Diabetes Therapeutics and Research Center, Institute of Advanced Medical Sciences, Tokushima University, Tokushima, Japan
| | - Munehide Matsuhisa
- Diabetes Therapeutics and Research Center, Institute of Advanced Medical Sciences, Tokushima University, Tokushima, Japan.
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Fadel IM, Ragab MH, Eid OM, Helmy NA, El-Bassyouni HT, Mazen I. IGF1R, IGFALS, and IGFBP3 gene copy number variations in a group of non-syndromic Egyptian short children. J Genet Eng Biotechnol 2021; 19:109. [PMID: 34322776 PMCID: PMC8319271 DOI: 10.1186/s43141-021-00202-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 06/27/2021] [Indexed: 11/10/2022]
Abstract
Background Insulin-like growth factor-1 (IGF-1) is required for normal intrauterine and postnatal growth, and this action is mediated through IGF1 receptor (IGF1R). IGF1R copy number variants (CNVs) can cause pre- and postnatal growth restriction, affecting an individual’s height. In this study, we used multiplex ligation-dependent probe amplification (MLPA) to detect CNVs in IGF1R, IGFALS, and IGFBP3 genes in the diagnostic workup of short stature for 40 Egyptian children with short stature. Results We detected a heterozygous deletion of IGF1R (exons 4 through 21) in 1 out of the 40 studied children (2.5%). Meanwhile, we did not detect any CNVs in either IGFALS or IGFBP3. Conclusion The diagnostic workup of short stature using MLPA for CNVs of IGF1R and other recognized height-related genes, such as SHOX and GH, in non-syndromic short stature children can be a fast and inexpensive diagnostic tool to recognize a subcategory of patients in which growth hormone treatment can be considered.
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Affiliation(s)
- Islam M Fadel
- Department of Human Cytogenetics, National Research Centre, El Buhouth St., Dokki, Cairo, 12622, Egypt.
| | - Moustafa H Ragab
- Department of Medical Environmental Research, Institute of Environmental Studies and Research, Ain Shams University, El Khalifa El Maamon Street, Cairo, 12622, Egypt
| | - Ola M Eid
- Department of Human Cytogenetics, National Research Centre, El Buhouth St., Dokki, Cairo, 12622, Egypt
| | - Nivine A Helmy
- Department of Human Cytogenetics, National Research Centre, El Buhouth St., Dokki, Cairo, 12622, Egypt
| | - Hala T El-Bassyouni
- Department of Clinical Genetics, National Research Centre, El Bohouth Street, Dokki, Cairo, 12622, Egypt
| | - Inas Mazen
- Department of Clinical Genetics, National Research Centre, El Bohouth Street, Dokki, Cairo, 12622, Egypt
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7
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Bioletto F, Parasiliti-Caprino M, Berton AM, Prencipe N, Cambria V, Ghigo E, Grottoli S, Gasco V. Development and Internal Validation of a Predictive Model for Adult GH Deficiency Prior to Stimulation Tests. Front Endocrinol (Lausanne) 2021; 12:737947. [PMID: 34630332 PMCID: PMC8498109 DOI: 10.3389/fendo.2021.737947] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 09/06/2021] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND The diagnosis of adult GH deficiency (GHD) relies on a reduced GH response to provocative tests. Their diagnostic accuracy, however, is not perfect, and a reliable estimation of pre-test GHD probability could be helpful for a better interpretation of their results. METHODS Eighty patients showing concordant GH response to two provocative tests, i.e. the insulin tolerance test and the GHRH + arginine test, were enrolled. Data on IGF-I values and on the presence/absence of other pituitary deficits were collected and integrated for the estimation of GHD probability prior to stimulation tests. RESULTS An independent statistically significant association with the diagnosis of GHD was found both for IGF-I SDS (OR 0.34, 95%-CI 0.18-0.65, p=0.001) and for the presence of other pituitary deficits (OR 6.55, 95%-CI 2.06-20.83, p=0.001). A low (<25%) pre-test GHD probability could be predicted when IGF-I SDS > +0.91 in the presence of other pituitary deficits or IGF-I SDS > -0.52 in the absence of other pituitary deficits. A high (>75%) pre-test GHD probability could be predicted when IGF-I SDS < -0.82 in the presence of other pituitary deficits or IGF-I SDS < -2.26 in the absence of other pituitary deficits. CONCLUSION This is the first study that proposes a quantitative estimation of GHD probability prior to stimulation tests. Our risk class stratification represents a simple tool that could be adopted for a Bayesian interpretation of stimulation test results, selecting patients who may benefit from a second stimulation test and possibly reducing the risk of wrong GHD diagnosis.
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Affiliation(s)
- Fabio Bioletto
- *Correspondence: Fabio Bioletto, ; orcid.org/0000-0001-7550-7023
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8
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Motte-Signoret E, Shankar-Aguilera S, Brailly-Tabard S, Soreze Y, Dell Orto V, Ben Ammar R, De Luca D, Boileau P. Small for Gestational Age Preterm Neonates Exhibit Defective GH/IGF1 Signaling Pathway. Front Pediatr 2021; 9:711400. [PMID: 34447729 PMCID: PMC8382944 DOI: 10.3389/fped.2021.711400] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 07/14/2021] [Indexed: 11/13/2022] Open
Abstract
Objective: To investigate the impact of fetal growth restriction (FGR) on hormonal regulation of post-natal growth and glucose metabolism [via insulin and growth hormone (GH)/Insulin-like Growth factor 1 (IGF1) axis pathways] in small for gestational age (SGA) neonates. Methods: We conducted a monocentric observational prospective comparative study on 73 singleton babies born with a weight inferior to 2,000 g. We analyzed auxological (weight, height and head circumference), and hormonal (GH, IGF1, and insulin plasma concentrations) data comparing SGA and appropriate for gestational age (AGA) neonates, between day 1 and 60. Results: One third (23/73) of the neonates were SGA. Twenty-five percent (18/73) required insulin for idiopathic hyperglycemia of prematurity and were smaller in weight and head circumference at discharge. In the SGA group compared with the AGA group, GH plasma concentrations were higher at day 3 (70.1 vs. 38.0 mIU/L) and IGF1 plasma concentrations were higher at day 10 (29.0 vs. 18.7 ng/ml). Conclusions: SGA neonates displayed resistance to GH and IGF1, concomitant to insulin resistance. This could partially explain the initial defective catch-up growth and, later in life, the higher prevalence of metabolic syndrome in this population.
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Affiliation(s)
- Emmanuelle Motte-Signoret
- Assistance Publique-Hôpitaux de Paris, Béclere Hospital, GH Paris Sud, Neonatal Intensive Care Unit, Clamart, France.,Poissy St Germain Hospital, Neonatal Intensive Care Unit, Poissy, France.,Paris-Saclay University, Université Versailles Saint Quentin, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, BREED, Jouy-en-Josas, France
| | - Shivani Shankar-Aguilera
- Assistance Publique-Hôpitaux de Paris, Béclere Hospital, GH Paris Sud, Neonatal Intensive Care Unit, Clamart, France
| | - Sylvie Brailly-Tabard
- Assistance Publique-Hôpitaux de Paris, Bicêtre Hospital, Molecular genetics Pharmacogenetics and Hormonology, Le Kremlin-Bicêtre, France
| | - Yohan Soreze
- Assistance Publique-Hôpitaux de Paris, Béclere Hospital, GH Paris Sud, Neonatal Intensive Care Unit, Clamart, France
| | - Valentina Dell Orto
- Assistance Publique-Hôpitaux de Paris, Béclere Hospital, GH Paris Sud, Neonatal Intensive Care Unit, Clamart, France
| | - Rafik Ben Ammar
- Assistance Publique-Hôpitaux de Paris, Béclere Hospital, GH Paris Sud, Neonatal Intensive Care Unit, Clamart, France
| | - Daniele De Luca
- Assistance Publique-Hôpitaux de Paris, Béclere Hospital, GH Paris Sud, Neonatal Intensive Care Unit, Clamart, France
| | - Pascal Boileau
- Poissy St Germain Hospital, Neonatal Intensive Care Unit, Poissy, France.,Institut National de la Santé et de la Recherche Médicale U1185, Le Kremlin-Bicêtre, France
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Baral K, Rotwein P. ZMAT2 in Humans and Other Primates: A Highly Conserved and Understudied Gene. Evol Bioinform Online 2020; 16:1176934320941500. [PMID: 32952394 PMCID: PMC7485168 DOI: 10.1177/1176934320941500] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 06/18/2020] [Indexed: 12/18/2022] Open
Abstract
Recent advances in genetics present unique opportunities for enhancing our
understanding of human physiology and disease predisposition through detailed
analysis of gene structure, expression, and population variation via examination
of data in publicly accessible genome and gene expression repositories. Yet, the
vast majority of human genes remain understudied. Here, we show the scope of
these genomic and genetic resources by evaluating ZMAT2, a
member of a 5-gene family that through May 2020 had been the focus of only 4
peer-reviewed scientific publications. Using analysis of information extracted
from public databases, we show that human ZMAT2 is a 6-exon
gene and find that it exhibits minimal genetic variation in human populations
and in disease states, including cancer. We further demonstrate that the gene
and its encoded protein are highly conserved among nonhuman primates and define
a cohort of ZMAT2 pseudogenes in the marmoset genome.
Collectively, our investigations illustrate how complementary use of genomic,
gene expression, and population genetic resources can lead to new insights about
human and mammalian biology and evolution, and when coupled with data supporting
key roles for ZMAT2 in keratinocyte differentiation and pre-RNA splicing argue
that this gene is worthy of further study.
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Affiliation(s)
- Kabita Baral
- Graduate School, College of Science, The University of Texas at El Paso, El Paso, TX, USA.,Department of Microbiology, University of Calgary, Calgary, AB, Canada
| | - Peter Rotwein
- Department of Molecular and Translational Medicine, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, TX, USA
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Rotwein P, Baral K. Zmat2 in mammals: conservation and diversification among genes and Pseudogenes. BMC Genomics 2020; 21:113. [PMID: 32005145 PMCID: PMC6995233 DOI: 10.1186/s12864-020-6506-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 01/17/2020] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Recent advances in genetics and genomics present unique opportunities for enhancing our understanding of mammalian biology and evolution through detailed multi-species comparative analysis of gene organization and expression. Yet, of the more than 20,000 protein coding genes found in mammalian genomes, fewer than 10% have been examined in any detail. Here we elucidate the power of data available in publicly-accessible genomic and genetic resources by querying them to evaluate Zmat2, a minimally studied gene whose human ortholog has been implicated in spliceosome function and in keratinocyte differentiation. RESULTS We find extensive conservation in coding regions and overall structure of Zmat2 in 18 mammals representing 13 orders and spanning ~ 165 million years of evolutionary development, and in their encoded proteins. We identify a tandem duplication in the Zmat2 gene and locus in opossum, but not in other monotremes, marsupials, or other mammals, indicating that this event occurred subsequent to the divergence of these species from one another. We also define a collection of Zmat2 pseudogenes in half of the mammals studied, and suggest based on phylogenetic analysis that they each arose independently in the recent evolutionary past. CONCLUSIONS Mammalian Zmat2 genes and ZMAT2 proteins illustrate conservation of structure and sequence, along with the development and diversification of pseudogenes in a large fraction of species. Collectively, these observations also illustrate how the focused identification and interpretation of data found in public genomic and gene expression resources can be leveraged to reveal new insights of potentially high biological significance.
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Affiliation(s)
- Peter Rotwein
- Department of Molecular and Translational Medicine, Paul L. Foster School of Medicine, Texas Tech Health University Health Sciences Center, El Paso, TX, 79905, USA.
| | - Kabita Baral
- Graduate School, College of Science, University of Texas at El Paso, El Paso, TX, 79902, USA
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11
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Renes JS, van Doorn J, Hokken-Koelega ACS. Current Insights into the Role of the Growth Hormone-Insulin-Like Growth Factor System in Short Children Born Small for Gestational Age. Horm Res Paediatr 2019; 92:15-27. [PMID: 31509834 PMCID: PMC6979433 DOI: 10.1159/000502739] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 08/14/2019] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND The reason for the insufficient catch-up growth seen in 10% of children born small for gestational age (SGA) is poorly understood. Disturbances in the growth hormone (GH) - insulin-like growth factor (IGF) axis might underlie this failure to show sufficient catch-up growth. CONCLUSION This review summarizes insights gained in the molecular and (epi) genetic mechanisms of the GH-IGF axis in short children born SGA. The most notable anomalies of the IGF system are the lowered IGF-I levels in both cord blood and the placenta, and the increased expression of IGF-binding proteins (IGFBP)-1 and IGFBP-2, which inhibit IGF-I, in the placenta of SGA neonates. These observations suggest a decreased bioactivity of IGF-I in utero. IGF-I levels remain reduced in SGA children with short stature, as well as IGFBP-3 and acid-labile subunit levels. Proteolysis of IGFBP-3 appears to be increased.
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Affiliation(s)
- Judith S Renes
- Department of Paediatrics, Subdivision of Endocrinology, Erasmus University Medical Centre, Sophia Children's Hospital, Rotterdam, The Netherlands,
| | - Jaap van Doorn
- Department of Genetics, Section of Metabolic Diagnostics, University Medical Centre Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Anita C S Hokken-Koelega
- Department of Paediatrics, Subdivision of Endocrinology, Erasmus University Medical Centre, Sophia Children's Hospital, Rotterdam, The Netherlands
- Dutch Growth Research Foundation, Rotterdam, The Netherlands
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12
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Rotwein P. Variation in the repulsive guidance molecule family in human populations. Physiol Rep 2019; 7:e13959. [PMID: 30746893 PMCID: PMC6370684 DOI: 10.14814/phy2.13959] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 11/28/2018] [Accepted: 11/29/2018] [Indexed: 01/17/2023] Open
Abstract
Repulsive guidance molecules, RGMA, RGMB, and RGMC, are related proteins discovered independently through different experimental paradigms. They are encoded by single copy genes in mammalian and other vertebrate genomes, and are ~50% identical in amino acid sequence. The importance of RGM actions in human physiology has not been realized, as most research has focused on non-human models, although mutations in RGMC are the cause of the severe iron storage disorder, juvenile hemochromatosis. Here I show that repositories of human genomic and population genetic data can be used as starting points for discovery and for developing new testable hypotheses about each of these paralogs in human biology and disease susceptibility. Information was extracted, aggregated, and analyzed from the Ensembl and UCSC Genome Browsers, the Exome Aggregation Consortium, the Genotype-Tissue Expression project portal, the cBio portal for Cancer Genomics, and the National Cancer Institute Genomic Data Commons data site. Results identify extensive variation in gene expression patterns, substantial alternative RNA splicing, and possible missense alterations and other modifications in the coding regions of each of the three genes, with many putative mutations being detected in individuals with different types of cancers. Moreover, selected amino acid substitutions are highly prevalent in the world population, with minor allele frequencies of up to 37% for RGMA and up to 8% for RGMB. These results indicate that protein sequence variation is common in the human RGM family, and raises the possibility that individual variants will have a significant population impact on human physiology and/or disease predisposition.
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Affiliation(s)
- Peter Rotwein
- Department of Biomedical SciencesPaul L. Foster School of MedicineTexas Tech Health University Health Sciences CenterEl PasoTexas
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13
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Giabicani E, Chantot-Bastaraud S, Bonnard A, Rachid M, Whalen S, Netchine I, Brioude F. Roles of Type 1 Insulin-Like Growth Factor (IGF) Receptor and IGF-II in Growth Regulation: Evidence From a Patient Carrying Both an 11p Paternal Duplication and 15q Deletion. Front Endocrinol (Lausanne) 2019; 10:263. [PMID: 31114545 PMCID: PMC6503735 DOI: 10.3389/fendo.2019.00263] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 04/09/2019] [Indexed: 12/23/2022] Open
Abstract
We report an original association of complex genetic defects in a patient carrying both an 11p paternal duplication, resulting in the double expression of insulin-like growth factor 2 (IGF2), as reported in Beckwith-Wiedemann syndrome, and a 15q terminal deletion, including the type 1 IGF receptor gene (IGF1R), resulting in haploinsufficiency for this gene. The patient was born with measurements appropriate for her gestational age but experienced growth retardation in early childhood, allowing a better comprehension of the IGF system in the pathophysiology of growth. It is possible that IGF-II plays a key role in fetal growth, independently of IGF1R signaling, and that its role is less important in post-natal growth, leaving IGF-I and growth hormone as the main actors.
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Affiliation(s)
- Eloïse Giabicani
- Sorbonne Université, INSERM, Centre de Recherche Saint Antoine, APHP, Hôpital Armand Trousseau, Explorations Fonctionnelles Endocriniennes, Paris, France
- *Correspondence: Eloïse Giabicani
| | - Sandra Chantot-Bastaraud
- Sorbonne Université, INSERM, Centre de Recherche Saint Antoine, APHP, Hôpital Armand Trousseau, Explorations Fonctionnelles Endocriniennes, Paris, France
- APHP, Hôpital Armand Trousseau, Département de Génétique, UF de Génétique Chromosomique, Paris, France
| | - Adeline Bonnard
- APHP, Hôpital Armand Trousseau, Département de Génétique, UF de Génétique Chromosomique, Paris, France
| | - Myriam Rachid
- APHP, Hôpital Armand Trousseau, Département de Génétique, UF de Génétique Chromosomique, Paris, France
| | - Sandra Whalen
- AP-HP, Hôpital Armand Trousseau, Department of Medical Genetics and Centre de Référence Anomalies du Développement et Syndromes Malformatifs et Déficiences Intellectuelles de Causes rares, Paris, France
| | - Irène Netchine
- Sorbonne Université, INSERM, Centre de Recherche Saint Antoine, APHP, Hôpital Armand Trousseau, Explorations Fonctionnelles Endocriniennes, Paris, France
| | - Frédéric Brioude
- Sorbonne Université, INSERM, Centre de Recherche Saint Antoine, APHP, Hôpital Armand Trousseau, Explorations Fonctionnelles Endocriniennes, Paris, France
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Yakar S, Werner H, Rosen CJ. Insulin-like growth factors: actions on the skeleton. J Mol Endocrinol 2018; 61:T115-T137. [PMID: 29626053 PMCID: PMC5966339 DOI: 10.1530/jme-17-0298] [Citation(s) in RCA: 125] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 04/06/2018] [Indexed: 12/20/2022]
Abstract
The discovery of the growth hormone (GH)-mediated somatic factors (somatomedins), insulin-like growth factor (IGF)-I and -II, has elicited an enormous interest primarily among endocrinologists who study growth and metabolism. The advancement of molecular endocrinology over the past four decades enables investigators to re-examine and refine the established somatomedin hypothesis. Specifically, gene deletions, transgene overexpression or more recently, cell-specific gene-ablations, have enabled investigators to study the effects of the Igf1 and Igf2 genes in temporal and spatial manners. The GH/IGF axis, acting in an endocrine and autocrine/paracrine fashion, is the major axis controlling skeletal growth. Studies in rodents have clearly shown that IGFs regulate bone length of the appendicular skeleton evidenced by changes in chondrocytes of the proliferative and hypertrophic zones of the growth plate. IGFs affect radial bone growth and regulate cortical and trabecular bone properties via their effects on osteoblast, osteocyte and osteoclast function. Interactions of the IGFs with sex steroid hormones and the parathyroid hormone demonstrate the significance and complexity of the IGF axis in the skeleton. Finally, IGFs have been implicated in skeletal aging. Decreases in serum IGFs during aging have been correlated with reductions in bone mineral density and increased fracture risk. This review highlights many of the most relevant studies in the IGF research landscape, focusing in particular on IGFs effects on the skeleton.
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Affiliation(s)
- Shoshana Yakar
- David B. Kriser Dental Center, Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, NY 10010-4086, USA
| | - Haim Werner
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Clifford J Rosen
- Maine Medical Center Research Institute, Scarborough, Maine 04074, USA
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Rotwein P. The complex genetics of human insulin-like growth factor 2 are not reflected in public databases. J Biol Chem 2018; 293:4324-4333. [PMID: 29414792 DOI: 10.1074/jbc.ra117.001573] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 01/15/2018] [Indexed: 01/02/2023] Open
Abstract
Recent advances in genetics present unique opportunities for enhancing knowledge about human physiology and disease susceptibility. Understanding this information at the individual gene level is challenging and requires extracting, collating, and interpreting data from a variety of public gene repositories. Here, I illustrate this challenge by analyzing the gene for human insulin-like growth factor 2 (IGF2) through the lens of several databases. IGF2, a 67-amino acid secreted peptide, is essential for normal prenatal growth and is involved in other physiological and pathophysiological processes in humans. Surprisingly, none of the genetic databases accurately described or completely delineated human IGF2 gene structure or transcript expression, even though all relevant information could be found in the published literature. Although IGF2 shares multiple features with the mouse Igf2 gene, it has several unique properties, including transcription from five promoters. Both genes undergo parental imprinting, with IGF2/Igf2 being expressed primarily from the paternal chromosome and the adjacent H19 gene from the maternal chromosome. Unlike mouse Igf2, whose expression declines after birth, human IGF2 remains active throughout life. This characteristic has been attributed to a unique human gene promoter that escapes imprinting, but as shown here, it involves several different promoters with distinct tissue-specific expression patterns. Because new testable hypotheses could lead to critical insights into IGF2 actions in human physiology and disease, it is incumbent that our fundamental understanding is accurate. Similar challenges affecting knowledge of other human genes should promote attempts to critically evaluate, interpret, and correct human genetic data in publicly available databases.
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Affiliation(s)
- Peter Rotwein
- From the Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech Health University Health Sciences Center, El Paso, Texas 79905
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16
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Abstract
Insulinlike growth factor (IGF) binding proteins (IGFBPs) 1 to 6 are high-affinity regulators of IGF activity. They generally inhibit IGF actions by preventing binding to the IGF-I receptor but can also enhance their actions under some conditions. Posttranslational modifications such as glycosylation and phosphorylation modulate IGFBP properties, and IGFBP proteolysis results in IGF release. IGFBPs have more recently been shown to have IGF-independent actions. A number of mechanisms are involved, including modulation of other growth factor pathways, nuclear localization and transcriptional regulation, interaction with the sphingolipid pathway, and binding to non-IGF biomolecules in the extracellular space and matrix, on the cell surface and intracellularly. IGFBPs modulate important biological processes, including cell proliferation, survival, migration, senescence, autophagy, and angiogenesis. Their actions have been implicated in growth, metabolism, cancer, stem cell maintenance and differentiation, and immune regulation. Recent studies have shown that epigenetic mechanisms are involved in the regulation of IGFBP abundance. A more complete understanding of IGFBP biology is necessary to further define their cellular roles and determine their therapeutic potential.
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Affiliation(s)
- Leon A Bach
- Department of Endocrinology and Diabetes, The Alfred Hospital, Melbourne, Victoria, Australia
- Department of Medicine, Alfred Medical Research and Education Precinct, Monash University, Melbourne, Victoria, Australia
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Rotwein P. Variation in Akt protein kinases in human populations. Am J Physiol Regul Integr Comp Physiol 2017; 313:R687-R692. [PMID: 28931550 DOI: 10.1152/ajpregu.00295.2017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 09/05/2017] [Accepted: 09/11/2017] [Indexed: 11/22/2022]
Abstract
The three Akt kinases are related proteins that are essential for normal growth and metabolic regulation and are implicated as key signaling mediators in many physiological and pathophysiological processes. Each Akt is activated by common biochemical signals that act downstream of growth factor and hormone receptors via phosphatidylinositol-3 kinase, and each controls several downstream pathways. The importance of Akt actions in human physiology is strengthened by the rarity of modifying mutations in their genes and by the devastating impact caused by these mutations on growth and development and in disorders such as cancer. Recent advances in genomics present unique opportunities for enhancing our understanding of human physiology and disease predisposition through the lens of population genetics, and the availability of DNA sequence data from 60,706 people in the Exome Aggregation Consortium has prompted this analysis. Results reveal a cohort of potential missense and other alterations in the coding regions of each AKT gene, but with nearly all changes being uncommon. The total number of different alleles per gene varied over an approximately threefold range, from 52 for AKT3 to 158 for AKT2, with variants distributed throughout all Akt protein domains. Previously characterized disease-causing mutations were found rarely in the general population. In contrast, a fairly prevalent amino acid substitution in AKT2 appears to be linked to increased predisposition for type 2 diabetes. Further analysis of variant Akt molecules as identified here will provide opportunities to understand the intricacies of Akt signaling and actions at a population level in human physiology and pathology.
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Affiliation(s)
- Peter Rotwein
- Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech Health University Health Sciences Center, El Paso, Texas
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Rotwein P. The New Genomics: What Molecular Databases Can Tell Us About Human Population Variation and Endocrine Disease. Endocrinology 2017; 158:2035-2042. [PMID: 28498917 PMCID: PMC7282473 DOI: 10.1210/en.2017-00338] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 05/08/2017] [Indexed: 11/25/2022]
Abstract
Major recent advances in genetics and genomics present unique opportunities for enhancing our understanding of human physiology and disease predisposition. Here I demonstrate how analysis of genomic information can provide new insights into endocrine systems, using the human growth hormone (GH) signaling pathway as an illustrative example. GH is essential for normal postnatal growth in children, and plays important roles in other biological processes throughout life. GH actions are mediated by the GH receptor, primarily via the JAK2 protein tyrosine kinase and the STAT5B transcription factor, and inactivating mutations in this pathway all lead to impaired somatic growth. Variation in GH signaling genes has been evaluated using DNA sequence data from the Exome Aggregation Consortium, a compendium of information from >60,000 individuals. Results reveal many potential missense and other alterations in the coding regions of GH1, GHR, JAK2, and STAT5B, with most changes being uncommon. The total number of different alleles per gene varied by ~threefold, from 101 for GH1 to 338 for JAK2. Several known disease-linked mutations in GH1, GHR, and JAK2 were present but infrequent in the population; however, three amino acid changes in GHR were sufficiently prevalent (~4% to 44% of chromosomes) to suggest that they are not disease causing. Collectively, these data provide new opportunities to understand how genetically driven variability in GH signaling and action may modify human physiology and disease.
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Affiliation(s)
- Peter Rotwein
- Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech Health University Health Sciences Center, El Paso, Texas 79905
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