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Abstract
PURPOSE OF REVIEW The purpose of this review is to provide a background on osteocytes and the primary cilium, discussing the role it plays in osteocyte mechanosensing. RECENT FINDINGS Osteocytes are thought to be the primary mechanosensing cells in bone tissue, regulating bone adaptation in response to exercise, with the primary cilium suggested to be a key mechanosensing mechanism in bone. More recent work has suggested that, rather than being direct mechanosensors themselves, primary cilia in bone may instead form a key chemo-signalling nexus for processing mechanoregulated signalling pathways. Recent evidence suggests that pharmacologically induced lengthening of the primary cilium in osteocytes may potentiate greater mechanotransduction, rather than greater mechanosensing. While more research is required to delineate the specific osteocyte mechanobiological molecular mechanisms governed by the primary cilium, it is clear from the literature that the primary cilium has significant potential as a therapeutic target to treat mechanoregulated bone diseases, such as osteoporosis.
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Affiliation(s)
- Stefaan W Verbruggen
- Department of Mechanical Engineering, University of Sheffield, Sheffield, UK.
- INSIGNEO Institute for in silico Medicine, University of Sheffield, Sheffield, UK.
- Centre for Predictive in vitro Models, Centre for Bioengineering, School of Engineering and Materials Science, Queen Mary University of London, London, E1 4NS, UK.
| | - Anuphan Sittichokechaiwut
- Department of Preventive Dentistry, Faculty of Dentistry, Naresuan University, Phitsanulok, Thailand
- Center of Excellence in Biomaterials, Naresuan University, Phitsanulok, Thailand
| | - Gwendolen C Reilly
- INSIGNEO Institute for in silico Medicine, University of Sheffield, Sheffield, UK
- Kroto Research Institute, Department of Materials Science and Engineering, University of Sheffield, Sheffield, UK
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Zubidat D, Hanna C, Randhawa AK, Smith BH, Chedid M, Kaidbay DHN, Nardelli L, Mkhaimer YG, Neal RM, Madsen CD, Senum SR, Gregory AV, Kline TL, Zoghby ZM, Broski SM, Issa NS, Harris PC, Torres VE, Sfeir JG, Chebib FT. Bone health in autosomal dominant polycystic kidney disease (ADPKD) patients after kidney transplantation. Bone Rep 2023; 18:101655. [PMID: 36659900 PMCID: PMC9842864 DOI: 10.1016/j.bonr.2023.101655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 12/29/2022] [Accepted: 01/09/2023] [Indexed: 01/12/2023] Open
Abstract
ADPKD is caused by pathogenic variants in PKD1 or PKD2, encoding polycystin-1 and -2 proteins. Polycystins are expressed in osteoblasts and chondrocytes in animal models, and loss of function is associated with low bone mineral density (BMD) and volume. However, it is unclear whether these variants impact bone strength in ADPKD patients. Here, we examined BMD in ADPKD after kidney transplantation (KTx). This retrospective observational study retrieved data from adult patients who received a KTx over the past 15 years. Patients with available dual-energy X-ray absorptiometry (DXA) of the hip and/or lumbar spine (LS) post-transplant were included. ADPKD patients (n = 340) were matched 1:1 by age (±2 years) at KTx and sex with non-diabetic non-ADPKD patients (n = 340). Patients with ADPKD had slightly higher BMD and T-scores at the right total hip (TH) as compared to non-ADPKD patients [BMD: 0.951 vs. 0.897, p < 0.001; T-score: -0.62 vs. -0.99, p < 0.001] and at left TH [BMD: 0.960 vs. 0.893, p < 0.001; T-score: -0.60 vs. -1.08, p < 0.001], respectively. Similar results were found at the right femoral neck (FN) between ADPKD and non-ADPKD [BMD: 0.887 vs. 0.848, p = 0.001; T-score: -1.20 vs. -1.41, p = 0.01] and at left FN [BMD: 0.885 vs. 0.840, p < 0.001; T-score: -1.16 vs. -1.46, p = 0.001]. At the LS level, ADPKD had a similar BMD and lower T-score compared to non-ADPKD [BMD: 1.120 vs. 1.126, p = 0.93; T-score: -0.66 vs. -0.23, p = 0.008]. After adjusting for preemptive KTx, ADPKD patients continued to have higher BMD T-scores in TH and FN. Our findings indicate that BMD by DXA is higher in patients with ADPKD compared to non-ADPKD patients after transplantation in sites where cortical but not trabecular bone is predominant. The clinical benefit of the preserved cortical bone BMD in patients with ADPKD needs to be explored in future studies.
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Affiliation(s)
- Dalia Zubidat
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, Rochester, MN, USA
| | - Christian Hanna
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, Rochester, MN, USA
- Division of Pediatric Nephrology and Hypertension, Department of Pediatric Adolescent Medicine, Mayo Clinic, Rochester, MN, USA
| | - Amarjyot K. Randhawa
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, Rochester, MN, USA
| | - Byron H. Smith
- Division of Clinical Trials and Biostatistics, Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN, USA
| | - Maroun Chedid
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, Rochester, MN, USA
| | - Daniel-Hasan N. Kaidbay
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, Rochester, MN, USA
| | - Luca Nardelli
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, Rochester, MN, USA
| | - Yaman G. Mkhaimer
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, Rochester, MN, USA
| | - Reem M. Neal
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, Rochester, MN, USA
| | - Charles D. Madsen
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, Rochester, MN, USA
| | - Sarah R. Senum
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, Rochester, MN, USA
| | | | | | - Ziad M. Zoghby
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, Rochester, MN, USA
| | | | - Naim S. Issa
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, Rochester, MN, USA
| | - Peter C. Harris
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, Rochester, MN, USA
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - Vicente E. Torres
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, Rochester, MN, USA
| | - Jad G. Sfeir
- Division of Endocrinology, Department of Medicine, Mayo Clinic, Rochester, MN, USA
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN, USA
| | - Fouad T. Chebib
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, Jacksonville, FL, USA
- Corresponding author at: 4500 San Pablo Rd S, Jacksonville, FL 32224, USA.
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De Rechter S, Bacchetta J, Godefroid N, Dubourg L, Cochat P, Maquet J, Raes A, De Schepper J, Vermeersch P, Van Dyck M, Levtchenko E, D'Haese P, Evenepoel P, Mekahli D. Evidence for Bone and Mineral Metabolism Alterations in Children With Autosomal Dominant Polycystic Kidney Disease. J Clin Endocrinol Metab 2017; 102:4210-4217. [PMID: 29092060 DOI: 10.1210/jc.2017-01157] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 09/13/2017] [Indexed: 01/08/2023]
Abstract
CONTEXT Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary kidney disease. Hypophosphatemia was demonstrated in adult patients with preserved renal function, together with high fibroblast growth factor 23 (FGF23) and low soluble Klotho levels. The latter explained the relative FGF23 hyporesponsiveness in this cohort. OBJECTIVE Evaluating phosphate and bone mineral metabolism in children with ADPKD compared with what is known in adult ADPKD patients. DESIGN Observational cross-sectional study. SETTING Multicenter study via ambulatory care in tertiary centers. PARTICIPANTS Ninety-two children with ADPKD (52 males; mean ± standard deviation age, 10.2 ± 5.0 years) and 22 healthy controls (HCs, 10 males; mean ± standard deviation age, 10.3 ± 4.1 years). MAIN OUTCOME MEASURES The predictor was early ADPKD stage. Bone mineral metabolism and renal phosphate handling were the main outcome measures. Performed measurements were serum phosphate, tubular maximum phosphorus reabsorption per glomerular filtration rate, FGF23, soluble Klotho, sclerostin, and bone alkaline phosphatase. RESULTS ADPKD children had significantly lower serum phosphate levels compared with HC. Low tubular maximum phosphorus reabsorption per glomerular filtration rate was observed in 24% of patients, although not significantly different from HC. Serum FGF23 and soluble Klotho levels were comparable between patients and HC. In addition, we showed decreased bone alkaline phosphatase levels in ADPKD children, suggesting suppressed bone formation. CONCLUSIONS This report demonstrates hypophosphatemia and suppressed bone formation in a pediatric ADPKD cohort, with preserved renal function, compared with HC. Although FGF23 levels were not different from controls, they should be considered inappropriate, given the concomitant hypophosphatemia. Further studies are required to elucidate underlying pathophysiology and potential clinical consequences.
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Affiliation(s)
- Stéphanie De Rechter
- Department of Pediatric Nephrology, University Hospitals Leuven, Leuven 3000, Belgium
- Laboratory of Pediatric Nephrology, KU Leuven, Leuven, Leuven 3000, Belgium
| | - Justine Bacchetta
- Centre de Référence des Maladies Rénales Rares, Hôpital Femme Mère Enfant, Hospices Civils de Lyon, 69500 Bron, France
| | - Nathalie Godefroid
- Department of Pediatric Nephrology, Cliniques Universitaires Saint-Luc, Brussels 1200, Belgium
| | - Laurence Dubourg
- Centre de Référence des Maladies Rénales Rares, Hôpital Femme Mère Enfant, Hospices Civils de Lyon, 69500 Bron, France
| | - Pierre Cochat
- Centre de Référence des Maladies Rénales Rares, Hôpital Femme Mère Enfant, Hospices Civils de Lyon, 69500 Bron, France
| | - Julie Maquet
- Department of Pediatric Nephrology, CHC, Liège 4420, Belgium
| | - Ann Raes
- Department of Pediatric Nephrology, University Hospitals Ghent, Ghent 9000, Belgium
| | - Jean De Schepper
- Department of Pediatric Endocrinology, Department of Pediatrics, Brussels University Hospital, Brussels 1090, Belgium
| | - Pieter Vermeersch
- Laboratory Medicine, University Hospitals Leuven 3000, Leuven, Belgium
| | - Maria Van Dyck
- Department of Pediatric Nephrology, University Hospitals Leuven, Leuven 3000, Belgium
- Laboratory of Pediatric Nephrology, KU Leuven, Leuven, Leuven 3000, Belgium
| | - Elena Levtchenko
- Department of Pediatric Nephrology, University Hospitals Leuven, Leuven 3000, Belgium
- Laboratory of Pediatric Nephrology, KU Leuven, Leuven, Leuven 3000, Belgium
| | - Patrick D'Haese
- Laboratory of Pathophysiology, University of Antwerp, Antwerp 2000, Belgium
| | - Pieter Evenepoel
- Department of Internal Medicine, Division of Nephrology, University Hospitals Leuven, Leuven 3000, Belgium
| | - Djalila Mekahli
- Department of Pediatric Nephrology, University Hospitals Leuven, Leuven 3000, Belgium
- Laboratory of Pediatric Nephrology, KU Leuven, Leuven, Leuven 3000, Belgium
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Abstract
Skeletal loading is an important physiological regulator of bone mass. Theoretically, mechanical forces or administration of drugs that activate bone mechanosensors would be a novel treatment for osteoporotic disorders, particularly age-related osteoporosis and other bone loss caused by skeletal unloading. Uncertainty regarding the identity of the molecular targets that sense and transduce mechanical forces in bone, however, has limited the therapeutic exploitation of mechanosesning pathways to control bone mass. Recently, two evolutionally conserved mechanosensing pathways have been shown to function as "physical environment" sensors in cells of the osteoblasts lineage. Indeed, polycystin-1 (Pkd1, or PC1) and polycystin-2 (Pkd2, or PC2' or TRPP2), which form a flow sensing receptor channel complex, and TAZ (transcriptional coactivator with PDZ-binding motif, or WWTR1), which responds to the extracellular matrix microenvironment act in concert to reciprocally regulate osteoblastogenesis and adipogenesis through co-activating Runx2 and a co-repressing PPARγ activities. Interactions of polycystins and TAZ with other putative mechanosensing mechanism, such as primary cilia, integrins and hemichannels, may create multifaceted mechanosensing networks in bone. Moreover, modulation of polycystins and TAZ interactions identify novel molecular targets to develop small molecules that mimic the effects of mechanical loading on bone.
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Affiliation(s)
- Zhousheng Xiao
- Department of Medicine, University of Tennessee Health Science Center, Memphis, TN 38165, USA
| | - Leigh Darryl Quarles
- Department of Medicine, University of Tennessee Health Science Center, Memphis, TN 38165, USA
- Coleman College of Medicine Building, Suite B216, University of Tennessee Health Science Center, 956 Court Avenue, Memphis, TN 38163, USA
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Lee KL, Guevarra MD, Nguyen AM, Chua MC, Wang Y, Jacobs CR. The primary cilium functions as a mechanical and calcium signaling nexus. Cilia 2015; 4:7. [PMID: 26029358 PMCID: PMC4448211 DOI: 10.1186/s13630-015-0016-y] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 04/28/2015] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND The primary cilium is an antenna-like, nonmotile structure that extends from the surface of most mammalian cell types and is critical for chemosensing and mechanosensing in a variety of tissues including cartilage, bone, and kidney. Flow-induced intracellular calcium ion (Ca(2+)) increases in kidney epithelia depend on primary cilia and primary cilium-localized Ca(2+)-permeable channels polycystin-2 (PC2) and transient receptor potential vanilloid 4 (TRPV4). While primary cilia have been implicated in osteocyte mechanotransduction, the molecular mechanism that mediates this process is not fully understood. We directed a fluorescence resonance energy transfer (FRET)-based Ca(2+) biosensor to the cilium by fusing the biosensor sequence to the sequence of the primary cilium-specific protein Arl13b. Using this tool, we investigated the role of several Ca(2+)-permeable channels that may mediate flow-induced Ca(2+) entry: PC2, TRPV4, and PIEZO1. RESULTS Here, we report the first measurements of Ca(2+) signaling within osteocyte primary cilia using a FRET-based biosensor fused to ARL13B. We show that fluid flow induces Ca(2+) increases in osteocyte primary cilia which depend on both intracellular Ca(2+) release and extracellular Ca(2+) entry. Using siRNA-mediated knockdowns, we demonstrate that TRPV4, but not PC2 or PIEZO1, mediates flow-induced ciliary Ca(2+) increases and loading-induced Cox-2 mRNA increases, an osteogenic response. CONCLUSIONS In this study, we show that the primary cilium forms a Ca(2+) microdomain dependent on Ca(2+) entry through TRPV4. These results demonstrate that the mechanism of mechanotransduction mediated by primary cilia varies in different tissue contexts. Additionally, we anticipate that this work is a starting point for more studies investigating the role of TRPV4 in mechanotransduction.
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Affiliation(s)
- Kristen L Lee
- />Department of Biomedical Engineering, Columbia University, 351 Engineering Terrace, MC 8904, 1210 Amsterdam Ave, New York, NY 10027 USA
| | - Marie D Guevarra
- />Department of Biomedical Engineering, Columbia University, 351 Engineering Terrace, MC 8904, 1210 Amsterdam Ave, New York, NY 10027 USA
| | - An M Nguyen
- />Department of Biomedical Engineering, Columbia University, 351 Engineering Terrace, MC 8904, 1210 Amsterdam Ave, New York, NY 10027 USA
- />Jacobs Technion-Cornell Innovation Institute, Cornell Tech, New York, NY 10011 USA
| | - Mardonn C Chua
- />Department of Biomedical Engineering, Columbia University, 351 Engineering Terrace, MC 8904, 1210 Amsterdam Ave, New York, NY 10027 USA
- />Department of Biotechnology, University of British Columbia, Vancouver, BC V6T 1Z4 Canada
| | - Yingxiao Wang
- />Bioengineering Department, UC San Diego, La Jolla, CA 92093 USA
| | - Christopher R Jacobs
- />Department of Biomedical Engineering, Columbia University, 351 Engineering Terrace, MC 8904, 1210 Amsterdam Ave, New York, NY 10027 USA
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From bone abnormalities to mineral metabolism dysregulation in autosomal dominant polycystic kidney disease. Pediatr Nephrol 2013; 28:2089-96. [PMID: 23340856 DOI: 10.1007/s00467-012-2384-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Revised: 11/27/2012] [Accepted: 11/28/2012] [Indexed: 01/02/2023]
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) is the most common monogenic cause of kidney failure. It is a systemic disorder, not only affecting the kidneys, but also associated with cyst formation in other organs such as the liver, spleen, pancreas, and seminal vesicles. Other extra-renal symptoms may consist of intracranial arterial aneurysms, cardiac valvular defects, abdominal and inguinal hernias and colonic diverticulosis. Very little is known regarding bone involvement in ADPKD; however, recent evidence has revealed the potential role of fibroblast growth factor 23 (FGF23). FGF23 is an endocrine fibroblast growth factor acting in the kidney as a phosphaturic hormone and a suppressor of active vitamin D with key effects on the bone/kidney/parathyroid axis, and has been shown to increase in patients with ADPKD, even with normal renal function. The aim of this review is to provide an overview of bone and mineral abnormalities found in experimental models and in patients with ADPKD, and to discuss the possible role of FGF23 in this disease.
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Nguyen AM, Jacobs CR. Emerging role of primary cilia as mechanosensors in osteocytes. Bone 2013; 54:196-204. [PMID: 23201223 PMCID: PMC3624072 DOI: 10.1016/j.bone.2012.11.016] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Revised: 10/06/2012] [Accepted: 11/19/2012] [Indexed: 01/08/2023]
Abstract
The primary cilium is a solitary, immotile microtubule-based extension present on nearly every mammalian cell. This organelle has established mechanosensory roles in several contexts including kidney, liver, and the embryonic node. Mechanical load deflects the cilium, triggering biochemical responses. Defects in cilium function have been associated with numerous human diseases. Recent research has implicated the primary cilium as a mechanosensor in bone. In this review, we discuss the cilium, the growing evidence for its mechanosensory role in bone, and areas of future study.
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Affiliation(s)
- An M Nguyen
- Department of Biomedical Engineering, Columbia University, New York, NY 10027, USA
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Xiao Z, Dallas M, Qiu N, Nicolella D, Cao L, Johnson M, Bonewald L, Quarles LD. Conditional deletion of Pkd1 in osteocytes disrupts skeletal mechanosensing in mice. FASEB J 2011; 25:2418-32. [PMID: 21454365 DOI: 10.1096/fj.10-180299] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We investigated whether polycystin-1 is a bone mechanosensor. We conditionally deleted Pkd1 in mature osteoblasts/osteocytes by crossing Dmp1-Cre with Pkd1(flox/m1Bei) mice, in which the m1Bei allele is nonfunctional. We assessed in wild-type and Pkd1-deficient mice the response to mechanical loading in vivo by ulna loading and ex vivo by measuring the response of isolated osteoblasts to fluid shear stress. We found that conditional Pkd1 heterozygotes (Dmp1-Cre;Pkd1(flox/+)) and null mice (Pkd1(Dmp1-cKO)) exhibited a ∼ 40 and ∼ 90% decrease, respectively, in functional Pkd1 transcripts in bone. Femoral bone mineral density (12 vs. 27%), trabecular bone volume (32 vs. 48%), and cortical thickness (6 vs. 17%) were reduced proportionate to the reduction of Pkd1 gene dose, as were mineral apposition rate (MAR) and expression of Runx2-II, Osteocalcin, Dmp1, and Phex. Anabolic load-induced periosteal lamellar MAR (0.58 ± 0.14; Pkd1(Dmp1-cKO) vs. 1.68 ± 0.34 μm/d; control) and increases in Cox-2, c-Jun, Wnt10b, Axin2, and Runx2-II gene expression were significantly attenuated in Pkd1(Dmp1-cKO) mice compared with controls. Application of fluid shear stress to immortalized osteoblasts from Pkd1(null/null) and Pkd1(m1Bei/m1Bei)-derived osteoblasts failed to elicit the increments in cytosolic calcium observed in wild-type controls. These data indicate that polycystin-1 is essential for the anabolic response to skeletal loading in osteoblasts/osteocytes.
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Affiliation(s)
- Zhousheng Xiao
- Department of Medicine, The University of Tennessee Health Science Center, Memphis, TN 38165, USA.
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9
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Xiao Z, Zhang S, Cao L, Qiu N, David V, Quarles LD. Conditional disruption of Pkd1 in osteoblasts results in osteopenia due to direct impairment of bone formation. J Biol Chem 2009; 285:1177-87. [PMID: 19887454 DOI: 10.1074/jbc.m109.050906] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
PKD1 (polycystin-1), the disease-causing gene for ADPKD, is widely expressed in various cell types, including osteoblasts, where its function is unknown. Although global inactivation of Pkd1 in mice results in abnormal skeletal development, the presence of polycystic kidneys and perinatal lethality confound ascertaining the direct osteoblastic functions of PKD1 in adult bone. To determine the role of PKD1 in osteoblasts, we conditionally inactivated Pkd1 in postnatal mature osteoblasts by crossing Oc (osteocalcin)-Cre mice with floxed Pkd1 (Pkd1(flox/m1Bei)) mice to generate conditional heterozygous (Oc-Cre;Pkd1(flox/+)) and homozygous (Oc-Cre;Pkd1(flox/m1Bei)) Pkd1-deficient mice. Cre-mediated recombination (Pkd1(Delta flox)) occurred exclusively in bone. Compared with control mice, the conditional deletion of Pkd1 from osteoblasts resulted in a gene dose-dependent reduction in bone mineral density, trabecular bone volume, and cortical thickness. In addition, mineral apposition rates and osteoblast-related gene expression, including Runx2-II (Runt-related transcription factor 2), osteocalcin, osteopontin, and bone sialoprotein, were reduced proportionate to the reduction of Pkd1 gene dose in bone of Oc-Cre;Pkd1(flox/+) and Oc-Cre;Pkd1(flox/m1Bei) mice. Primary osteoblasts derived from Oc-Cre;Pkd1(flox/m1Bei) displayed impaired differentiation and suppressed activity of the phosphatidylinositol 3-kinase-Akt-GSK3beta-beta-catenin signaling pathways. The conditional deletion of Pkd1 also resulted in increased adipogenesis in bone marrow and in osteoblast cultures. Thus, PKD1 directly functions in osteoblasts to regulate bone formation.
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Affiliation(s)
- Zhousheng Xiao
- Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas 66160, USA
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Abstract
Although the expression of cilia on chondrocytes was described over 40 years ago, the importance of this organelle in skeletal development and maintenance has only recently been recognized. Primary cilia are found on most mammalian cells and have been shown to play a role in chemosensation and mechanosensation. A growing number of human pleiotropic syndromes have been shown to be associated with ciliary or basal body dysfunction. Skeletal phenotypes, including alterations in limb patterning, endochondral bone formation, craniofacial development, and dentition, have been described in several of these syndromes. Additional insights into the potential roles and mechanisms of cilia action in the mammalian skeleton have been provided by research in model organisms including mouse and zebrafish. In this article we describe what is currently known about the localization of cilia in the skeleton as well as the roles and underlying molecular mechanisms of cilia in skeletal development.
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Affiliation(s)
- Courtney J Haycraft
- Department of Medicine/Division of Nephrology, Medical University of South Carolina, Charleston, SC 29425, USA
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11
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Sicca F, Silengo M, Parrini E, Ferrero GB, Guerrini R. Subcortical band heterotopia with simplified gyral pattern and syndactyly. Am J Med Genet A 2003; 119A:207-10. [PMID: 12749065 DOI: 10.1002/ajmg.a.20111] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We describe a girl with an unusual form of subcortical band heterotopia (SBH) and a complex malformation syndrome. SBH had an irregular inner margin, organized in contiguous fascicles of migrating neurons, sometimes giving the appearance of many small contiguous gyri. The true cortex had decreased thickness and showed a simplified gyral pattern with decreased number of gyri, which were usually of increased width, and shallow sulci. The cerebellum was hypoplastic. Additional features included epicanthal folds, hypertelorism, small nose with hypoplastic nares, bilateral syndactyly of the toes, pulmonary valve stenosis, atrial and ventricular septal defects. At the age of 1 year the patient had severe developmental delay and epilepsy. Chromosome studies and mutation analysis of the DCX and LIS1 genes gave negative results. This observation delineates a new multiple congenital abnormalities mental retardation syndrome and confirms genetic heterogeneity of SBH.
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Affiliation(s)
- Federico Sicca
- Division of Child Neurology and Psychiatry, University of Pisa, Pisa, Italy
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Kantaputra PN, Chalidapong P. Are triphalangeal thumb-polysyndactyly syndrome (TPTPS) and tibial hemimelia-polysyndactyly-triphalangeal thumb syndrome (THPTTS) identical? A father with TPTPS and his daughter with THPTTS in a Thai family. AMERICAN JOURNAL OF MEDICAL GENETICS 2000; 93:126-31. [PMID: 10869115 DOI: 10.1002/1096-8628(20000717)93:2<126::aid-ajmg9>3.0.co;2-s] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We report on a Thai man who had triphalangeal thumb-polysyndactyly syndrome (TPTPS, MIM *190605) and his daughter who had tibial hemimelia-polysyndactyly-triphalangeal thumb syndrome (THPTTS, MIM *188770). The father had polysyndactyly of triphalangeal thumbs, syndactyly of fingers, duplicated distal phalanx of the left great toe, brachymesophalangy of toes, and the absence of middle phalanges of some toes. He was diagnosed as having TPTPS. His daughter was more severely affected, having complete syndactyly of five-fingered hands in rosebud fashion (Haas-type syndactyly), hypoplastic tibiae, absent patellae, thick and displaced fibulae, preaxial polysyndactyly of triphalangeal toes, and cutaneous syndactyly of some toes, the manifestations being consistent with THPTTS. Having two different syndromes in the same family suggests that they are actually the same disorder. A literature survey showed that there have been several families where THPTTS occurred with TPTPS or Haas-type syndactyly (and/or preaxial polydactyly type 2, PPD2). In addition, all loci for TPTPS, THPTTS, and PPD2 (and/or PPD3) have been assigned to chromosome band 7q36. These findings support our conclusion that TPTPS, PPD2 (and/or PPD3), and Haas-type syndactyly are a single genetic en-tity (THPTTS). We propose to call the condition "tibial hemimelia-polysyndactyly-triphalangeal thumbs syndrome."
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MESH Headings
- Adult
- Child, Preschool
- Diagnosis, Differential
- Ectromelia/diagnostic imaging
- Ectromelia/genetics
- Family Health
- Female
- Foot Deformities, Congenital/diagnostic imaging
- Foot Deformities, Congenital/genetics
- Foot Deformities, Congenital/pathology
- Hand Deformities, Congenital/diagnostic imaging
- Hand Deformities, Congenital/genetics
- Hand Deformities, Congenital/pathology
- Humans
- Limb Deformities, Congenital/diagnostic imaging
- Limb Deformities, Congenital/genetics
- Limb Deformities, Congenital/pathology
- Male
- Polydactyly/diagnostic imaging
- Polydactyly/genetics
- Radiography
- Syndactyly/diagnostic imaging
- Syndactyly/genetics
- Syndrome
- Terminology as Topic
- Thumb/abnormalities
- Thumb/diagnostic imaging
- Tibia/abnormalities
- Tibia/diagnostic imaging
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Affiliation(s)
- P N Kantaputra
- Department of Pediatric Dentistry, Faculty of Dentistry, Chiang Mai University, Thailand.
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13
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Sinibaldi D, Malena S, Mingarelli R, Rizzoni G. Prenatal ultrasonographic findings of dominant polycystic kidney disease and postnatal renal evolution. AMERICAN JOURNAL OF MEDICAL GENETICS 1996; 65:337-41. [PMID: 8923946 DOI: 10.1002/(sici)1096-8628(19961111)65:4<337::aid-ajmg17>3.0.co;2-v] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) is a relatively common genetic disorder, and its prenatal diagnosis has been reported with increasing frequency. Nevertheless, no data are available on the significance of prenatal ultrasound (US) patterns in predicting postnatal renal function and outcome. We report on one case of ADPKD diagnosed prenatally by US, and on two cases diagnosed immediately after birth, with different prenatal US and renal outcomes. Data on prenatal US findings and postnatal renal evolution are scanty and largely incomplete. Apparently, none of the prenatal findings are consistently different in cases with and without normal postnatal renal function and blood pressure. More complete information on prenatal US findings and postnatal renal evolution is urgently needed.
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Affiliation(s)
- D Sinibaldi
- Division of Nephrology and Dialysis, Bambino Gesù Children's Hospital, Rome, Italy
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14
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15
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16
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Turco AE, Padovani EM, Peissel B, Chiaffoni GP, Rossetti S, Gammaro L, Maschio G, Pignatti PF. Gene linkage analysis and DNA based detection of autosomal dominant polycystic kidney disease (ADPKD) in a newborn infant. Case report. J Perinat Med 1995; 23:205-12. [PMID: 8568612 DOI: 10.1515/jpme.1995.23.3.205] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Bilateral polycystic kidneys were detected by ultrasound at 23 weeks gestation in a male fetus. Bilateral renal cysts were subsequently also found in the asymptomatic propositus' mother and grandmother, suggesting the diagnosis of autosomal dominant polycystic kidney disease (ADPKD). The renal ultrasonograms showed cortical cysts with normal or decreased-sized kidneys. Renal function was normal. Seven available members of the family were genotyped for flanking DNA markers tightly linked to the PKD1 gene on chromosome 16p, and for a polymorphism close to a second putative disease gene (PKD2) on chromosome 2. The genetic linkage approach allowed us to detect with a high degree of accuracy the ADPKD1 at risk chromosome in the three patients, as well as in a 28-year-old unaffected female. This report illustrates the feasibility and the usefulness of recent molecular genetic strategies for diagnostic purposes in ADPKD, especially when clinical and radiological data are atypical. Furthermore, it also confirms that early or very early onset forms of the disease are not uncommon, and should be considered in the differential diagnosis of childhood cystic disease.
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Affiliation(s)
- A E Turco
- Institute of Genetics, University of Verona School of Medicine, Italy
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17
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Turco AE, Peissel B, Rossetti S, Pignatti PF, Padovani EM, Chiaffoni GP. Skeletal malformations and polycystic kidney disease. J Med Genet 1994; 31:741-2. [PMID: 7815449 PMCID: PMC1050093 DOI: 10.1136/jmg.31.9.741-a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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18
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Michaud J, Russo P, Grignon A, Dallaire L, Bichet D, Rosenblatt D, Lamothe E, Lambert M. Autosomal dominant polycystic kidney disease in the fetus. AMERICAN JOURNAL OF MEDICAL GENETICS 1994; 51:240-6. [PMID: 8074152 DOI: 10.1002/ajmg.1320510314] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
We report on 3 cases with a fetal presentation of autosomal dominant polycystic kidney disease (ADPKD), which illustrate the variable expression of ADPKD during fetal life. Fetus 1 was diagnosed at 20 weeks of gestation by ultrasonography; a molecular prenatal diagnosis was performed at 10 weeks on fetus 2, a sib of fetus 1; and ADPKD was an incidental finding in fetus 3 who was aborted at 16 weeks for anencephaly. All pregnancies were terminated and pathologic studies of the fetal kidneys were performed. From these cases and a review of the literature, we draw the following conclusions: (1) so far, all fetal ADPKD kidneys that have been histologically studied have shown cystic dilatations; 28/32 of these fetuses had ultrasonographic manifestations of the disease and/or had sibs with an early-onset form of it; (2) these cysts can be found in newly formed nephrons (fetus 2), predominantly in the more mature nephrons of the deep cortex (fetus 1) or more sparsely distributed in the cortex (fetus 3); these different patterns may reflect different rates of progression of the disease; (3) in contrast to the histologic findings in adult kidneys, glomeruli seem to be predominantly affected in fetal ADPKD; (4) severe fetal expression of ADPKD seems to cluster in some families; and (5) so far, all DNA analyses performed in families with subjects presenting during the fetal or neonatal period have been consistent with linkage to the PKD1 locus.
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Affiliation(s)
- J Michaud
- Department of Pediatrics, Hôpital Sainte-Justine, Montréal, Québec, Canada
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19
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Turco AE, Peissel B, Rossetti S, Selicorni A, Manoukian S, Brusasco A, Tadini G, Galimberti A, Tassis B, Turolla L. Prenatal testing in a fetus at risk for autosomal dominant polycystic kidney disease and autosomal recessive junctional epidermolysis bullosa with pyloric atresia. AMERICAN JOURNAL OF MEDICAL GENETICS 1993; 47:1225-30. [PMID: 8291561 DOI: 10.1002/ajmg.1320470820] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Amniocentesis and fetal skin biopsies were performed at 18 weeks of gestation in a fetus at risk for autosomal dominant polycystic kidney disease (ADPKD) and autosomal recessive junctional epidermolysis bullosa (EBJ) with pyloric atresia. A previous son of the couple under investigation had died at 3 months of EBJ. The mother of the propositus has ADPKD. Genetic linkage studies were carried out in 11 relatives (4 with ADPKD), and on fetal DNA obtained from cultured amniocytes, using 8 flanking DNA markers tightly linked to the PKD1 locus on chromosome 16p, and a DNA marker linked to another putative ADPKD locus on chromosome 2p. The linkage results indicated that the fetus had not inherited the ADPKD chromosome from the affected mother, with a diagnostic accuracy of > 99%. Ultrastructural and immunohistochemical analyses of multiple fetal skin biopsies showed no EBJ-associated abnormalities. Thus, combining recent morphological and molecular diagnostic methods, we could show that the fetus was free from both diseases. After 40 weeks of gestation, a normal male infant was delivered.
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Affiliation(s)
- A E Turco
- Institute of Biological Sciences and Genetics, University of Verona School of Medicine, Italy
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20
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Emery A. Archibald Garrod--and the Individuality of Man. J Med Genet 1993. [DOI: 10.1136/jmg.30.11.973-b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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21
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MESH Headings
- Abnormalities, Multiple/classification
- Abnormalities, Multiple/diagnosis
- Abnormalities, Multiple/genetics
- Foot Deformities, Congenital/classification
- Foot Deformities, Congenital/diagnosis
- Foot Deformities, Congenital/genetics
- Hand Deformities, Congenital/classification
- Hand Deformities, Congenital/diagnosis
- Hand Deformities, Congenital/genetics
- Humans
- Infant, Newborn
- Polycystic Kidney, Autosomal Dominant/genetics
- Polydactyly/classification
- Polydactyly/diagnosis
- Polydactyly/genetics
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