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Tian E, Rothermel C, Michel Z, de Castro LF, Lee J, Kilts T, Kent T, Collins MT, Ten Hagen KG. Loss of the glycosyltransferase Galnt11 affects vitamin D homeostasis and bone composition. J Biol Chem 2024; 300:107164. [PMID: 38484798 PMCID: PMC11001633 DOI: 10.1016/j.jbc.2024.107164] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 03/04/2024] [Accepted: 03/07/2024] [Indexed: 04/07/2024] Open
Abstract
O-glycosylation is a conserved posttranslational modification that impacts many aspects of organismal viability and function. Recent studies examining the glycosyltransferase Galnt11 demonstrated that it glycosylates the endocytic receptor megalin in the kidneys, enabling proper binding and reabsorption of ligands, including vitamin D-binding protein (DBP). Galnt11-deficient mice were unable to properly reabsorb DBP from the urine. Vitamin D plays an essential role in mineral homeostasis and its deficiency is associated with bone diseases such as rickets, osteomalacia, and osteoporosis. We therefore set out to examine the effects of the loss of Galnt11 on vitamin D homeostasis and bone composition. We found significantly decreased levels of serum 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D, consistent with decreased reabsorption of DBP. This was accompanied by a significant reduction in blood calcium levels and a physiologic increase in parathyroid hormone (PTH) in Galnt11-deficient mice. Bones in Galnt11-deficient mice were smaller and displayed a decrease in cortical bone accompanied by an increase in trabecular bone and an increase in a marker of bone formation, consistent with PTH-mediated effects on bone. These results support a unified model for the role of Galnt11 in bone and mineral homeostasis, wherein loss of Galnt11 leads to decreased reabsorption of DBP by megalin, resulting in a cascade of disrupted mineral and bone homeostasis including decreased circulating vitamin D and calcium levels, a physiological increase in PTH, an overall loss of cortical bone, and an increase in trabecular bone. Our study elucidates how defects in O-glycosylation can influence vitamin D and mineral homeostasis and the integrity of the skeletal system.
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Affiliation(s)
- E Tian
- Developmental Glycobiology Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, USA
| | - Caroline Rothermel
- Developmental Glycobiology Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, USA
| | - Zachary Michel
- Skeletal Disorders and Mineral Homeostasis Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, USA
| | - Luis Fernandez de Castro
- Skeletal Disorders and Mineral Homeostasis Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, USA
| | - Jeeyoung Lee
- Developmental Glycobiology Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, USA
| | - Tina Kilts
- Developmental Glycobiology Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, USA
| | - Tristan Kent
- Skeletal Disorders and Mineral Homeostasis Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, USA
| | - Michael T Collins
- Skeletal Disorders and Mineral Homeostasis Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, USA
| | - Kelly G Ten Hagen
- Developmental Glycobiology Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, USA.
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Tift C, D'Souza P, Johnston J, Acosta M, Nicoli ER, Rothermel C, Thurm A, Karunakara A, Thorp B, Ross P, Jameson J, Sheehan M, Vaughn T, Valencia D, De Boever E. eP259: A phase 1/2 trial of AXO-AAV-GM1 gene therapy for the treatment of infantile- and juvenile-onset GM1 gangliosidosis. Genet Med 2022. [DOI: 10.1016/j.gim.2022.01.294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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Renner G, Rothermel C, Krampen G. Befunde zur Reliabilität und Validität des Mottier-Tests in einer klinisch-sozialpädiatrischen Stichprobe. Sprache Stimme Gehör 2008. [DOI: 10.1055/s-2007-1004546] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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