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Rosario FJ, Chopra A, Biggar K, Powell TL, Gupta MB, Jansson T. Placental Remote Control of Fetal Metabolism: Trophoblast mTOR Signaling Regulates Liver IGFBP-1 Phosphorylation and IGF-1 Bioavailability. Int J Mol Sci 2023; 24:7273. [PMID: 37108437 PMCID: PMC10138459 DOI: 10.3390/ijms24087273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 04/02/2023] [Accepted: 04/06/2023] [Indexed: 04/29/2023] Open
Abstract
The mechanisms mediating the restricted growth in intrauterine growth restriction (IUGR) remain to be fully established. Mechanistic target of rapamycin (mTOR) signaling functions as a placental nutrient sensor, indirectly influencing fetal growth by regulating placental function. Increased secretion and the phosphorylation of fetal liver IGFBP-1 are known to markedly decrease the bioavailability of IGF-1, a major fetal growth factor. We hypothesized that an inhibition of trophoblast mTOR increases liver IGFBP-1 secretion and phosphorylation. We collected conditioned media (CM) from cultured primary human trophoblast (PHT) cells with a silenced RAPTOR (specific inhibition of mTOR Complex 1), RICTOR (inhibition of mTOR Complex 2), or DEPTOR (activates both mTOR Complexes). Subsequently, HepG2 cells, a well-established model for human fetal hepatocytes, were cultured in CM from PHT cells, and IGFBP-1 secretion and phosphorylation were determined. CM from PHT cells with either mTORC1 or mTORC2 inhibition caused the marked hyperphosphorylation of IGFBP-1 in HepG2 cells as determined by 2D-immunoblotting while Parallel Reaction Monitoring-Mass Spectrometry (PRM-MS) identified increased dually phosphorylated Ser169 + Ser174. Furthermore, using the same samples, PRM-MS identified multiple CK2 peptides coimmunoprecipitated with IGFBP-1 and greater CK2 autophosphorylation, indicating the activation of CK2, a key enzyme mediating IGFBP-1 phosphorylation. Increased IGFBP-1 phosphorylation inhibited IGF-1 function, as determined by the reduced IGF-1R autophosphorylation. Conversely, CM from PHT cells with mTOR activation decreased IGFBP-1 phosphorylation. CM from non-trophoblast cells with mTORC1 or mTORC2 inhibition had no effect on HepG2 IGFBP-1 phosphorylation. Placental mTOR signaling may regulate fetal growth by the remote control of fetal liver IGFBP-1 phosphorylation.
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Affiliation(s)
- Fredrick J. Rosario
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Anand Chopra
- Institute of Biochemistry, Carleton University, Ottawa, ON K1S 5B6, Canada
| | - Kyle Biggar
- Institute of Biochemistry, Carleton University, Ottawa, ON K1S 5B6, Canada
| | - Theresa L. Powell
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
- Section of Neonatology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
- Department of Biochemistry, University of Western Ontario, London, ON N6A 3K7, Canada
| | - Madhulika B. Gupta
- Department of Biochemistry, University of Western Ontario, London, ON N6A 3K7, Canada
- Department of Pediatrics, University of Western Ontario, London, ON N6A 3K7, Canada
- Children’s Health Research Institute, University of Western Ontario, London, ON N6A 3K7, Canada
| | - Thomas Jansson
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
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Giacomozzi C, Martin A, Fernández MC, Gutiérrez M, Iascone M, Domené HM, Dominici FP, Bergadá I, Cangiano B, Persani L, Pennisi PA. Novel Insulin-Like Growth Factor 1 Gene Mutation: Broadening of the Phenotype and Implications for Insulin Resistance. J Clin Endocrinol Metab 2022; 108:1355-1369. [PMID: 36546343 DOI: 10.1210/clinem/dgac738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 11/23/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022]
Abstract
PURPOSE Insulin-like Growth Factor (IGF)1 gene mutations are extremely rare causes of pre- and post-natal growth retardation. Phenotype can be heterogenous with varying degrees of neurosensory deafness, cognitive defects, glucose metabolism impairment and short stature. This study describes a 12.6-year-old girl presenting severe short stature and insulin resistance, but with normal hearing and neurological development at the lower limit of normal. METHODS DNA was obtained from the proband and both parents for whole exome sequencing (WES). In silico analysis was performed to predict the impact of the IGF1 variant on IGF1 and insulin receptors (IGF1R and IR) signalling. Phosphorylation of the IGF1R at activating Tyr residues and cell proliferation analyses were used to assess the ability of each subject's IGF1 to bind and activate IGF1R. RESULTS The proband had low immunoreactive IGF1 in serum and WES revealed a novel homozygous IGF1 missense variant (c.247A > T), causing a change of serine 83 for cysteine (p.Ser83Cys; p.Ser35Cys in mature peptide). The proband's parents were heterozygous for this mutation. In silico analyses indicated the pathogenic potential of the variant with electrostatic variations with the potential of hampering the interaction with the IGF1R but strengthening the binding to IR. The mutant IGF1 protein had a significantly reduced activity on in vitro bioassays. MAIN CONCLUSIONS We describe a novel IGF1 mutation leading to severe loss of circulating IGF1 immunoreactivity and bioactivity, In silico modelling predicts that the mutant IGF1 could interfere with IR signalling, providing a possible explanation for the severe insulin resistance observed in the patient. The absence of significant hearing and neurodevelopmental involvement in the present case is unusual and broadens the clinical spectrum of IGF1 mutations.
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Affiliation(s)
- Claudio Giacomozzi
- Unit of Pediatrics, Department of Maternal and Child Health, Carlo Poma Hospital, ASST-Mantova, Mantua, Italy
| | - Ayelen Martin
- Centro de Investigaciones Endocrinológicas 'Dr César Bergadá' (CEDIE) CONICET - FEI - División de Endocrinología, Hospital de Niños Dr. Ricardo Gutiérrez, Buenos Aires, Argentina
| | - María Celia Fernández
- Centro de Investigaciones Endocrinológicas 'Dr César Bergadá' (CEDIE) CONICET - FEI - División de Endocrinología, Hospital de Niños Dr. Ricardo Gutiérrez, Buenos Aires, Argentina
| | - Mariana Gutiérrez
- Centro de Investigaciones Endocrinológicas 'Dr César Bergadá' (CEDIE) CONICET - FEI - División de Endocrinología, Hospital de Niños Dr. Ricardo Gutiérrez, Buenos Aires, Argentina
| | - Maria Iascone
- Department of Medical Genetics, ASST Papa Giovanni XXIII, Bergamo, Italy
| | - Horacio M Domené
- Centro de Investigaciones Endocrinológicas 'Dr César Bergadá' (CEDIE) CONICET - FEI - División de Endocrinología, Hospital de Niños Dr. Ricardo Gutiérrez, Buenos Aires, Argentina
| | - Fernando P Dominici
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Química Biológica (IQUIFIB-CONICET), Buenos Aires, Argentina
| | - Ignacio Bergadá
- Centro de Investigaciones Endocrinológicas 'Dr César Bergadá' (CEDIE) CONICET - FEI - División de Endocrinología, Hospital de Niños Dr. Ricardo Gutiérrez, Buenos Aires, Argentina
| | - Biagio Cangiano
- Department of Medical Biotechnology and Translational Medicine, University of Milan, 20100 Milan, Italy
- Department of Endocrine and Metabolic Diseases, IRCCS Istituto Auxologico Italiano, 20100 Milan, Italy
| | - Luca Persani
- Department of Medical Biotechnology and Translational Medicine, University of Milan, 20100 Milan, Italy
- Department of Endocrine and Metabolic Diseases, IRCCS Istituto Auxologico Italiano, 20100 Milan, Italy
| | - Patricia A Pennisi
- Centro de Investigaciones Endocrinológicas 'Dr César Bergadá' (CEDIE) CONICET - FEI - División de Endocrinología, Hospital de Niños Dr. Ricardo Gutiérrez, Buenos Aires, Argentina
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Abstract
Intrauterine growth restriction (IUGR) leads to the development of type 2 diabetes in adulthood, and the permanent alterations in gene expression implicate an epigenetic mechanism. Using a rat model of IUGR, we performed TrueSeq-HELP Tagging to assess the association of DNA methylation changes and gene dysregulation in islets. We identified 511 differentially methylated regions (DMRs) and 4377 significantly altered single CpG sites. Integrating the methylome and our published transcriptome data sets resulted in the identification of pathways critical for islet function. The identified DMRs were enriched with transcription factor binding motifs, such as Elk1, Etv1, Foxa1, Foxa2, Pax7, Stat3, Hnf1, and AR. In silico analysis of 3-dimensional chromosomal interactions using human pancreas and islet Hi-C data sets identified interactions between 14 highly conserved DMRs and 35 genes with significant expression changes at an early age, many of which persisted in adult islets. In adult islets, there were far more interactions between DMRs and genes with significant expression changes identified with Hi-C, and most of them were critical to islet metabolism and insulin secretion. The methylome was integrated with our published genome-wide histone modification data sets from IUGR islets, resulting in further characterization of important regulatory regions of the genome altered by IUGR containing both significant changes in DNA methylation and specific histone marks. We identified novel regulatory regions in islets after exposure to IUGR, suggesting that epigenetic changes at key transcription factor binding motifs and other gene regulatory regions may contribute to gene dysregulation and an abnormal islet phenotype in IUGR rats.
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Affiliation(s)
- Yu-Chin Lien
- Center for Research on Reproduction and Women’s Health, Perelman School of Medicine, the University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Division of Neonatology, Department of Pediatrics, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA
| | - Sara E Pinney
- Center for Research on Reproduction and Women’s Health, Perelman School of Medicine, the University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Division Endocrinology and Diabetes, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA
- Perlman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Xueqing Maggie Lu
- Institute for Biomedical Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Rebecca A Simmons
- Center for Research on Reproduction and Women’s Health, Perelman School of Medicine, the University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Division of Neonatology, Department of Pediatrics, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA
- Perlman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Correspondence: Rebecca A. Simmons, MD, Center for Research on Reproduction and Women’s Health, Perelman School of Medicine, the University of Pennsylvania, BRB II/III, 13th Fl, Rm 1308, 421 Curie Blvd, Philadelphia, PA 19104, USA.
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