1
|
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.
Collapse
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.
| |
Collapse
|
2
|
Michel Z, Raborn LN, Spencer T, Pan K, Martin D, Roszko KL, Wang Y, Robey PG, Collins MT, Boyce AM, de Castro Diaz LF. Transcriptomic signature and pro-osteoclastic secreted factors of abnormal bone marrow stromal cells in fibrous dysplasia. bioRxiv 2024:2024.02.23.581225. [PMID: 38529507 PMCID: PMC10962707 DOI: 10.1101/2024.02.23.581225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/27/2024]
Abstract
Fibrous dysplasia (FD) is a mosaic skeletal disorder caused by somatic activating variants in GNAS , encoding for Gα s , which leads to excessive cAMP signaling in bone marrow stromal cells (BMSCs). Despite advancements in our understanding of FD pathophysiology, the effect of Gα s activation in the BMSC transcriptome remains unclear, as well as how this translates into their local influence in the lesional microenvironment. In this study, we analyzed changes induced by Gα s activation in BMSC transcriptome and performed a comprehensive analysis of their production of cytokines and other secreted factors. We performed RNAseq of cultured BMSCs from patients with FD and healthy volunteers, and from an inducible mouse model of FD, and combined their transcriptomic profiles to build a robust FD BMSC genetic signature. Pathways related to Gα s activation, cytokine signaling, and extracellular matrix deposition were identified. In addition, a comprehensive profile of their secreted cytokines and other factors was performed to identify modulation of several key factors we hypothesized to be involved in FD pathogenesis. We also screened circulating cytokines in a collection of plasma samples from patients with FD, finding positive correlations of several cytokines to their disease burden score, as well as to one another and bone turnover markers. Overall, these data support a pro-inflammatory, pro-osteoclastic behavior of BMSCs bearing hyperactive Gα s variants, and point to several cytokines and other secreted factors as possible therapeutic targets and/or circulating biomarkers for FD.
Collapse
|
3
|
de Castro LF, Whitlock JM, Michel Z, Pan K, Taylor J, Szymczuk V, Boyce B, Martin D, Kram V, Galisteo R, Melikov K, Chernomordik LV, Collins MT, Boyce AM. RANKL inhibition reduces lesional cellularity and Gα s variant expression and enables osteogenic maturation in fibrous dysplasia. Bone Res 2024; 12:10. [PMID: 38378678 PMCID: PMC10879491 DOI: 10.1038/s41413-023-00311-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 11/15/2023] [Accepted: 12/15/2023] [Indexed: 02/22/2024] Open
Abstract
Fibrous dysplasia (FD) is a rare, disabling skeletal disease for which there are no established treatments. Growing evidence supports inhibiting the osteoclastogenic factor receptor activator of nuclear kappa-B ligand (RANKL) as a potential treatment strategy. In this study, we investigated the mechanisms underlying RANKL inhibition in FD tissue and its likely indirect effects on osteoprogenitors by evaluating human FD tissue pre- and post-treatment in a phase 2 clinical trial of denosumab (NCT03571191) and in murine in vivo and ex vivo preclinical models. Histological analysis of human and mouse tissue demonstrated increased osteogenic maturation, reduced cellularity, and reduced expression of the pathogenic Gαs variant in FD lesions after RANKL inhibition. RNA sequencing of human and mouse tissue supported these findings. The interaction between osteoclasts and mutant osteoprogenitors was further assessed in an ex vivo lesion model, which indicated that the proliferation of abnormal FD osteoprogenitors was dependent on osteoclasts. The results from this study demonstrated that, in addition to its expected antiosteoclastic effect, denosumab reduces FD lesion activity by decreasing FD cell proliferation and increasing osteogenic maturation, leading to increased bone formation within lesions. These findings highlight the unappreciated role of cellular crosstalk between osteoclasts and preosteoblasts/osteoblasts as a driver of FD pathology and demonstrate a novel mechanism of action of denosumab in the treatment of bone disease.TRIAL REGISTRATION: ClinicalTrials.gov NCT03571191.
Collapse
Affiliation(s)
- Luis F de Castro
- Skeletal Disorders and Mineral Homeostasis Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Jarred M Whitlock
- Section on Membrane Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Zachary Michel
- Skeletal Disorders and Mineral Homeostasis Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Kristen Pan
- Metabolic Bone Disorders Unit, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
- Department of Plastic and Reconstructive Surgery, The Johns Hopkins Medical Institutions, Baltimore, MD, USA
| | - Jocelyn Taylor
- Metabolic Bone Disorders Unit, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Vivian Szymczuk
- Metabolic Bone Disorders Unit, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Brendan Boyce
- Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, NY, USA
| | - Daniel Martin
- NIDCR Genomics and Computational Biology Core, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Vardit Kram
- Metabolic Bone Disorders Unit, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Rebeca Galisteo
- Skeletal Disorders and Mineral Homeostasis Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Kamran Melikov
- Section on Membrane Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Leonid V Chernomordik
- Section on Membrane Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Michael T Collins
- Skeletal Disorders and Mineral Homeostasis Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Alison M Boyce
- Metabolic Bone Disorders Unit, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA.
| |
Collapse
|
4
|
Ovejero D, Michel Z, Cataisson C, Saikali A, Galisteo R, Yuspa SH, Collins MT, de Castro LF. Murine models of HRAS-mediated cutaneous skeletal hypophosphatemia syndrome suggest bone as the FGF23 excess source. J Clin Invest 2023; 133:159330. [PMID: 36943390 PMCID: PMC10145192 DOI: 10.1172/jci159330] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 03/14/2023] [Indexed: 03/23/2023] Open
Abstract
Cutaneous Skeletal Hypophosphatemia Syndrome (CSHS) is a mosaic RASopathy characterized by the association of dysplastic skeletal lesions, congenital skin nevi of epidermal and/or melanocytic origin, and fibroblast growth factor-23 (FGF23)-mediated hypophosphatemia. The primary physiological source of circulating FGF23 is bone cells. However, several reports have suggested skin lesions as the source of excess FGF23 in CSHS. Consequently, without convincing evidence of efficacy, many patients with CSHS have undergone painful removal of cutaneous lesions in an effort to normalize blood phosphate levels.This study aims to elucidate whether the source of FGF23 excess in CSHS is RAS mutation-bearing bone or skin lesions. Towards this end, we analyzed the expression and activity of Fgf23 in two mouse models expressing similar HRAS/Hras activating mutations in a mosaic-like fashion in either bone or epidermal tissue. We found that HRAS hyperactivity in bone, not skin, caused excess of bioactive intact FGF23, hypophosphatemia and osteomalacia.Our findings support RAS-mutated dysplastic bone as the primary source of physiologically active FGF23 excess in patients with CSHS. This evidence informs the care of patients with CSHS, arguing against the practice of nevi removal to decrease circulating, physiologically active FGF23.
Collapse
Affiliation(s)
- Diana Ovejero
- Musculoskeletal Research Unit, IMIM (Hospital del Mar Medical Research Institute), Barcelona, Spain
| | - Zachary Michel
- Skeletal Disorders and Mineral Homeostasis Section, National Institute of Dental and Craniofacial Research (NIDCR), National In, Bethesda, United States of America
| | | | - Amanda Saikali
- Skeletal Disorders and Mineral Homeostasis Section, National Institute of Dental and Craniofacial Research (NIDCR), National In, Bethesda, United States of America
| | - Rebeca Galisteo
- Skeletal Disorders and Mineral Homeostasis Section, National Institute of Dental and Craniofacial Research (NIDCR), National In, Bethesda, United States of America
| | | | - Michael T Collins
- Skeletal Disorders and Mineral Homeostasis Section, National Institute of Dental and Craniofacial Research (NIDCR), National In, Bethesda, United States of America
| | - Luis F de Castro
- Skeletal Disorders and Mineral Homeostasis Section, National Institute of Dental and Craniofacial Research (NIDCR), National In, Bethesda, United States of America
| |
Collapse
|
5
|
de Castro LF, Michel Z, Pan K, Taylor J, Szymczuk V, Paravastu S, Saboury B, Papadakis GZ, Li X, Milligan K, Boyce B, Paul SM, Collins MT, Boyce AM. Safety and Efficacy of Denosumab for Fibrous Dysplasia of Bone. N Engl J Med 2023; 388:766-768. [PMID: 36812441 PMCID: PMC10015375 DOI: 10.1056/nejmc2214862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Affiliation(s)
| | | | | | | | | | | | | | | | - Xiaobai Li
- National Institutes of Health, Bethesda, MD
| | | | - Brendan Boyce
- University of Rochester Medical Center, Rochester, NY
| | | | | | | |
Collapse
|
6
|
Szymczuk V, Taylor J, Michel Z, Sinaii N, Boyce AM. Skeletal Disease Acquisition in Fibrous Dysplasia: Natural History and Indicators of Lesion Progression in Children. J Bone Miner Res 2022; 37:1473-1478. [PMID: 35695414 DOI: 10.1002/jbmr.4618] [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: 03/15/2022] [Revised: 05/20/2022] [Accepted: 06/04/2022] [Indexed: 11/11/2022]
Abstract
Fibrous dysplasia (FD) is a rare mosaic disorder resulting in fractures, pain, and disability. Bone lesions appear during childhood and expand during skeletal growth. The rate at which FD lesions progress and the biochemical determinants of FD lesion formation have not been established, making it difficult to investigate and implement preventative therapies. The purpose of this study was to characterize FD lesion progression in children, and to identify clinical variables associated with progressive disease. Clinical data and imaging from an ongoing natural history study at the National Institutes of Health (NIH) were reviewed. 99m-Technetium methylene diphosphonate (99Tc-MDP) scans were used to determine Skeletal Burden Score (SBS), a validated quantitative scoring system. FD progression rate was determined by the change in the SBS in each patient per year. Thirty-one children had serial 99Tc-MDP scans, with a median age at first scan of 6 years (interquartile range [IQR] 4-8, range 2-10), and median follow-up 1.1 years (IQR 1.1-2.1, range 0.7-11.2). The median FD progression rate for the total group was 2.12 SBS units/year (IQR 0.81-2.94, range 0.05-7.81). FD progression rates were highest in children under age 8 years and declined with age (p = 0.03). Baseline disease severity was associated with subsequent disease progression (p = 0.009), with the highest FD progression rates in patients with moderate disease (baseline SBS 16-30), and lowest progression rates in those with severe disease (SBS ≥50). Serum levels of the bone formation marker osteocalcin were positively correlated with subsequent FD progression rate (p = 0.01, R = 0.58). There was no association between FD progression and baseline endocrinopathies, fractures, or surgery rates. FD lesions progress during childhood, particularly in younger children and those with moderate involvement. Osteocalcin may potentially serve as a biomarker for progressive disease. These findings may allow clinicians to investigate preventative therapies, and to identify children with FD who are candidates for early interventions. Published 2022. This article is a U.S. Government work and is in the public domain in the USA.
Collapse
Affiliation(s)
- Vivian Szymczuk
- Metabolic Bone Disorders Unit, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA.,Pediatric Endocrinology Inter-Institute Training Program, National Institute of Child Health and Development, National Institutes of Health, Bethesda, MD, USA
| | - Jocelyn Taylor
- Metabolic Bone Disorders Unit, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Zachary Michel
- Skeletal Disorders and Mineral Homeostasis Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Ninet Sinaii
- Biostatistics and Clinical Epidemiology Service, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Alison M Boyce
- Metabolic Bone Disorders Unit, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| |
Collapse
|
7
|
Abstract
PURPOSE To report two cases of cat-scratch fever with atypical posterior segment manifestations. METHODS Two cases were retrospectively reviewed. RESULTS A 27-year-old woman presented with painless blurring of central vision in her left eye. Clinical examination revealed a small focal area of retinitis within the macula associated with a subtle macular star. Spectral-domain optical coherence tomography showed a hyper-reflective inner retinal lesion in addition to subretinal and intraretinal fluid as well as hyperreflective foci within the outer plexiform layer. Serology was positive for anti-B. henselae IgM (titer 1:32). A 34-year-old woman presented with painless loss of vision in both eyes associated with headaches and pain with extraocular movement. Spectral-domain optical coherence tomography depicted subretinal fluid, intraretinal fluid, and hyperreflective deposits within the outer plexiform layer. A focal collection of vitreous cell was observed overlying the optic nerve in the left eye. Bilateral disk leakage was identified on fluorescein angiography. Serology revealed high-titer anti-B. henselae antibodies (IgM titers 1:32, IgG titers 1:256). CONCLUSION Our cases highlight the necessity of recognizing more unusual posterior segment presentations of ocular bartonellosis. Multimodal retinal imaging including spectral-domain optical coherence tomography may help better characterize lesions.
Collapse
Affiliation(s)
- Zachary Michel
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon; and
| | - Travis Redd
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon; and
| | - Kavita V Bhavsar
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon; and
- Portland VA Healthcare System, Portland, Oregon
| |
Collapse
|
8
|
Bhavsar KV, Michel Z, Greenwald M, Cunningham ET, Freund KB. Retinal injury from handheld lasers: a review. Surv Ophthalmol 2020; 66:231-260. [PMID: 32628946 DOI: 10.1016/j.survophthal.2020.06.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 06/25/2020] [Accepted: 06/29/2020] [Indexed: 11/24/2022]
Abstract
Retinal photic injury induced by handheld lasers is a burgeoning public health concern due to the wider accessibility of high-powered devices. Retinal damage from thermal energy can cause potentially severe and permanent vision loss in children and young adults who are particularly vulnerable because of comorbid behavioral, learning, and psychiatric impairments. Understanding the spectrum of specific clinical and imaging features of such laser injuries aids in prompt and accurate diagnosis. Multimodal retinal imaging is important for the identification of the outer retinal abnormalities that characterize this condition. We reviewed 171 reported cases in the English and non-English language literature published from 1999, when handheld laser injury was first described, to December, 2018. Risk factors, demographic and clinical characteristics, as well as multimodal imaging findings, were collected and summarized. These findings both provide insights for public health awareness and guide areas of future investigation.
Collapse
Affiliation(s)
- Kavita V Bhavsar
- Casey Eye Institute, Oregon Health & Science` University, Portland, OR, USA; Portland VA Healthcare System, Portland, OR, USA.
| | - Zachary Michel
- Casey Eye Institute, Oregon Health & Science` University, Portland, OR, USA
| | - Miles Greenwald
- Casey Eye Institute, Oregon Health & Science` University, Portland, OR, USA
| | - Emmett T Cunningham
- The Department of Ophthalmology, California Pacific Medical Center, San Francisco, CA, USA; The Department of Ophthalmology, Stanford University School of Medicine, San Francisco, CA, USA; The Francis I. Proctor Foundation, UCSF School of Medicine, San Francisco, CA, USA; West Coast Retina Medical Group, San Francisco, CA, USA
| | - K Bailey Freund
- Vitreous Retina Macula Consultants of New York, New York, NY, USA; LuEsther T. Mertz Retinal Research Center, Manhattan Eye, Ear and Throat Hospital, New York, NY, USA; Department of Ophthalmology, New York University Langone Medical Center, New York, NY, USA; Department of Ophthalmology, Columbia University, New York, NY, USA
| |
Collapse
|