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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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Gossing W, Radke L, Biering H, Diederich S, Mai K, Frohme M. The ElonginB/C-Cullin5-SOCS-Box-Complex Is a Potential Biomarker for Growth Hormone Disorders. Biomedicines 2021; 9:biomedicines9020201. [PMID: 33671326 PMCID: PMC7921923 DOI: 10.3390/biomedicines9020201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Revised: 01/31/2021] [Accepted: 02/08/2021] [Indexed: 01/29/2023] Open
Abstract
Insulin-like growth factor 1 (IGF-1) is the standard biochemical marker for the diagnosis and treatment control of acromegaly and growth hormone deficiency (GHD). However, its limitations necessitate the screening for new specific and sensitive biomarkers. The elonginB/C-cullin5-SOCS-box-complex (ECS-complex) (an intracellular five-protein complex) is stimulated by circulating growth hormone (GH) and regulates GH receptor levels through a negative feedback loop. It mediates the cells' sensitivity for GH and therefore, represents a potent new biomarker for those diseases. In this study, individual ECS-complex proteins were measured in whole blood samples of patients with acromegaly (n = 32) or GHD (n = 12) via ELISA and compared to controls. Hierarchical clustering of the results revealed that by combining the three ECS-complex proteins suppressor of cytokine signaling 2 (SOCS2), cullin-5 and ring-box protein 2 (Rbx-2), 93% of patient samples could be separated from controls, despite many patients having a normal IGF-1 or not receiving medical treatment. SOCS2 showed the best individual diagnostic performance with an overall accuracy of 0.93, while the combination of the three proteins correctly identified all patients and controls. This resulted in perfect sensitivity and specificity for all patient groups, which demonstrates potential benefits of the ECS-complex proteins as clinical biomarkers for the diagnostics of GH-related diseases and substantiates their important role in GH metabolism.
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Affiliation(s)
- Wilhelm Gossing
- Division Molecular Biotechnology and Functional Genomics, Technical University of Applied Sciences, 15745 Wildau, Germany; (W.G.); (L.R.); (H.B.)
- Department of Endocrinology and Metabolism, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany; (S.D.); (K.M.)
| | - Lars Radke
- Division Molecular Biotechnology and Functional Genomics, Technical University of Applied Sciences, 15745 Wildau, Germany; (W.G.); (L.R.); (H.B.)
| | - Henrik Biering
- Division Molecular Biotechnology and Functional Genomics, Technical University of Applied Sciences, 15745 Wildau, Germany; (W.G.); (L.R.); (H.B.)
- Praxis an der Kaisereiche, Innere Medizin, Endokrinologie, Diabetologie, 12159 Berlin, Germany
| | - Sven Diederich
- Department of Endocrinology and Metabolism, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany; (S.D.); (K.M.)
- MVZ Medicover Berlin-Mitte, Innere Medizin, Endokrinologie, Andrologie, 10117 Berlin, Germany
| | - Knut Mai
- Department of Endocrinology and Metabolism, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany; (S.D.); (K.M.)
- German Centre for Cardiovascular Research (DZHK), Partner Site Berlin, 10117 Berlin, Germany
| | - Marcus Frohme
- Division Molecular Biotechnology and Functional Genomics, Technical University of Applied Sciences, 15745 Wildau, Germany; (W.G.); (L.R.); (H.B.)
- Correspondence:
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