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Li Y, Liu S, Pan D, Xu B, Xing X, Zhou H, Zhang B, Zhou S, Ning G, Feng S. The potential role and trend of HIF‑1α in intervertebral disc degeneration: Friend or foe? (Review). Mol Med Rep 2021; 23:239. [PMID: 33537810 PMCID: PMC7893690 DOI: 10.3892/mmr.2021.11878] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 11/08/2019] [Indexed: 12/11/2022] Open
Abstract
Lower back pain (LBP) is one of the most common reasons for seeking medical advice in orthopedic clinics. Increasingly, research has shown that symptomatic intervertebral disc degeneration (IDD) is mostly related to LBP. This review first outlines the research and findings of studies into IDD, from the physiological structure of the intervertebral disc (IVD) to various pathological cascades. The vicious cycles of IDD are re-described in relation to the analysis of the relationship among the pathological mechanisms involved in IDD. Interestingly, a ‘chief molecule’ was found, hypoxia-inducible factor-1α (HIF-1α), that may regulate all other mechanisms involved in IDD. When the vicious cycle is established, the low oxygen tension activates the expression of HIF-1α, which subsequently enters into the hypoxia-induced HIF pathways. The HIF pathways are dichotomized as friend and foe pathways according to the oxygen tension of the IVD microenvironment. Combined with clinical outcomes and previous research, the trend of IDD development has been predicted in this paper. Lastly, an early precautionary diagnosis and treatment method is proposed whereby nucleus pulposus tissue for biopsy can be obtained through IVD puncture guided by B-ultrasound when the patient is showing symptoms but MRI imaging shows negative results. The assessment criteria for biopsy and the feasibility, superiority and challenges of this approach have been discussed. Overall, it is clear that HIF-1α is an indispensable reference indicator for the accurate diagnosis and treatment of IDD.
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Affiliation(s)
- Yongjin Li
- Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China
| | - Shen Liu
- Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China
| | - Dayu Pan
- Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China
| | - Baoshan Xu
- Department of Spine Surgery, Tianjin Hospital, Tianjin 300000, P.R. China
| | - Xuewu Xing
- Department of Orthopedic Surgery, First Central Clinical of Tianjin Medical University, Tianjin 300052, P.R. China
| | - Hengxing Zhou
- Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China
| | - Bin Zhang
- Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China
| | - Suzhe Zhou
- Department of Orthopedics, The Affiliated Zhongshan Hospital of Fudan University, Shanghai 200034, P.R. China
| | - Guangzhi Ning
- Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China
| | - Shiqing Feng
- Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China
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Yan JF, Qin WP, Xiao BC, Wan QQ, Tay FR, Niu LN, Jiao K. Pathological calcification in osteoarthritis: an outcome or a disease initiator? Biol Rev Camb Philos Soc 2020; 95:960-985. [PMID: 32207559 DOI: 10.1111/brv.12595] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 02/27/2020] [Accepted: 03/02/2020] [Indexed: 12/12/2022]
Abstract
In the progression of osteoarthritis, pathological calcification in the affected joint is an important feature. The role of these crystallites in the pathogenesis and progression of osteoarthritis is controversial; it remains unclear whether they act as a disease initiator or are present as a result of joint damage. Recent studies reported that the molecular mechanisms regulating physiological calcification of skeletal tissues are similar to those regulating pathological or ectopic calcification of soft tissues. Pathological calcification takes place when the equilibrium is disrupted. Calcium phosphate crystallites are identified in most affected joints and the presence of these crystallites is closely correlated with the extent of joint destruction. These observations suggest that pathological calcification is most likely to be a disease initiator instead of an outcome of osteoarthritis progression. Inhibiting pathological crystallite deposition within joint tissues therefore represents a potential therapeutic target in the management of osteoarthritis.
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Affiliation(s)
- Jian-Fei Yan
- Department of Oral Mucosal Diseases, State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, School of Stomatology, The Fourth Military Medical University, 145 changle xi road, Xi'an, Shaanxi, 710032, China
| | - Wen-Pin Qin
- Department of Oral Mucosal Diseases, State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, School of Stomatology, The Fourth Military Medical University, 145 changle xi road, Xi'an, Shaanxi, 710032, China
| | - Bo-Cheng Xiao
- Department of Oral Mucosal Diseases, State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, School of Stomatology, The Fourth Military Medical University, 145 changle xi road, Xi'an, Shaanxi, 710032, China
| | - Qian-Qian Wan
- Department of Oral Mucosal Diseases, State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, School of Stomatology, The Fourth Military Medical University, 145 changle xi road, Xi'an, Shaanxi, 710032, China
| | - Franklin R Tay
- Department of Oral Mucosal Diseases, State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, School of Stomatology, The Fourth Military Medical University, 145 changle xi road, Xi'an, Shaanxi, 710032, China.,Department of Endodontics, College of Graduate Studies, Augusta University, 1430, John Wesley Gilbert Drive, Augusta, GA, 30912, U.S.A
| | - Li-Na Niu
- Department of Oral Mucosal Diseases, State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, School of Stomatology, The Fourth Military Medical University, 145 changle xi road, Xi'an, Shaanxi, 710032, China
| | - Kai Jiao
- Department of Oral Mucosal Diseases, State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, School of Stomatology, The Fourth Military Medical University, 145 changle xi road, Xi'an, Shaanxi, 710032, China
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Mitton-Fitzgerald E, Gohr CM, Bettendorf B, Rosenthal AK. The Role of ANK in Calcium Pyrophosphate Deposition Disease. Curr Rheumatol Rep 2016; 18:25. [PMID: 27032788 DOI: 10.1007/s11926-016-0574-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The protein product of the progressive ankylosis gene, known as ANK, is a 492-amino acid multi-pass transmembrane protein. This protein is critical for the regulation of pyrophosphate, and gain of function ANK mutations is associated with calcium pyrophosphate deposition disease. Much about the structure, function, and regulation of ANK remain unstudied. This review of the current literature examines recent contributions to our understanding of ANK. We focus on new work on the function, binding partners, and regulators of ANK. A more complete understanding of this important protein may help to identify future therapeutic targets for the treatment of calcium pyrophosphate deposition disease.
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Affiliation(s)
- Elizabeth Mitton-Fitzgerald
- The Division of Rheumatology, Department of Medicine, Medical College of Wisconsin and the Zablocki VA Medical Center, Milwaukee, WI, 53295-1000, USA
| | - Claudia M Gohr
- The Division of Rheumatology, Department of Medicine, Medical College of Wisconsin and the Zablocki VA Medical Center, Milwaukee, WI, 53295-1000, USA.
| | - Brittany Bettendorf
- The Division of Rheumatology, Department of Medicine, Medical College of Wisconsin and the Zablocki VA Medical Center, Milwaukee, WI, 53295-1000, USA
| | - Ann K Rosenthal
- The Division of Rheumatology, Department of Medicine, Medical College of Wisconsin and the Zablocki VA Medical Center, Milwaukee, WI, 53295-1000, USA
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de la Croix Ndong J, Makowski AJ, Uppuganti S, Vignaux G, Ono K, Perrien DS, Joubert S, Baglio SR, Granchi D, Stevenson DA, Rios JJ, Nyman JS, Elefteriou F. Asfotase-α improves bone growth, mineralization and strength in mouse models of neurofibromatosis type-1. Nat Med 2014; 20:904-10. [PMID: 24997609 PMCID: PMC4126855 DOI: 10.1038/nm.3583] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Accepted: 05/01/2014] [Indexed: 12/20/2022]
Abstract
Mineralization of the skeleton depends on the balance between levels of
pyrophosphate (PPi), an inhibitor of hydroxyapatite formation, and phosphate generated
from PPi breakdown by alkaline phosphatase (ALP). We report here that ablation of
Nf1, encoding the RAS/GTPase–activating protein neurofibromin,
in bone–forming cells leads to supraphysiologic PPi accumulation, caused by a
chronic ERK–dependent increase in genes promoting PPi synthesis and extracellular
transport, namely Enpp1 and Ank. It also prevents
BMP2–induced osteoprogenitor differentiation and, consequently, expression of ALP
and PPi breakdown, further contributing to PPi accumulation. The short stature, impaired
bone mineralization and strength in mice lacking Nf1 in
osteochondroprogenitors or osteoblasts could be corrected by enzyme therapy aimed at
reducing PPi concentration. These results establish neurofibromin as an essential
regulator of bone mineralization, suggest that altered PPi homeostasis contributes to the
skeletal dysplasiae associated with neurofibromatosis type-1 (NF1), and that some of the
NF1 skeletal conditions might be preventable pharmacologically.
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Affiliation(s)
- Jean de la Croix Ndong
- 1] Vanderbilt Center for Bone Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA. [2] Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Alexander J Makowski
- 1] Vanderbilt Center for Bone Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA. [2] Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA. [3] Department of Orthopaedic Surgery &Rehabilitation, Vanderbilt University Medical Center, Nashville, Tennessee, USA. [4] Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, Tennessee, USA
| | - Sasidhar Uppuganti
- 1] Vanderbilt Center for Bone Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA. [2] Department of Orthopaedic Surgery &Rehabilitation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Guillaume Vignaux
- 1] Vanderbilt Center for Bone Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA. [2] Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Koichiro Ono
- 1] Vanderbilt Center for Bone Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA. [2] Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA. [3] Department of Orthopaedics, Nohon Koukan Hospital, Kawasaki, Kanagawa, Japan
| | - Daniel S Perrien
- 1] Vanderbilt Center for Bone Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA. [2] Department of Orthopaedic Surgery &Rehabilitation, Vanderbilt University Medical Center, Nashville, Tennessee, USA. [3] Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, Tennessee, USA. [4] Vanderbilt University Institute of Imaging Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | | | - Serena R Baglio
- Laboratory for Orthopedic Pathophysiology and Regenerative Medicine, Istituto Ortopedico Rizzoli, Bologna, Italy
| | - Donatella Granchi
- Laboratory for Orthopedic Pathophysiology and Regenerative Medicine, Istituto Ortopedico Rizzoli, Bologna, Italy
| | - David A Stevenson
- Department of Pediatrics, University of Utah, Salt Lake City, Utah, USA
| | - Jonathan J Rios
- 1] Sarah M. and Charles E. Seay Center for Musculoskeletal Research, Texas Scottish Rite Hospital for Children, Dallas, Texas, USA. [2] Department of Pediatrics, UT Southwestern Medical Center, Dallas, Texas, USA. [3] Eugene McDermott Center for Human Growth &Development, UT Southwestern Medical Center, Dallas, Texas, USA. [4] Department of Orthopaedic Surgery, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Jeffry S Nyman
- 1] Vanderbilt Center for Bone Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA. [2] Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA. [3] Department of Orthopaedic Surgery &Rehabilitation, Vanderbilt University Medical Center, Nashville, Tennessee, USA. [4] Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, Tennessee, USA
| | - Florent Elefteriou
- 1] Vanderbilt Center for Bone Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA. [2] Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA. [3] Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee, USA. [4] Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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Xu H, Zhang X, Wang H, Zhang Y, Shi Y, Zhang X. Continuous cyclic mechanical tension increases ank expression in endplate chondrocytes through the TGF-β1 and p38 pathway. Eur J Histochem 2013; 57:e28. [PMID: 24085277 PMCID: PMC3794359 DOI: 10.4081/ejh.2013.e28] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2013] [Revised: 08/22/2013] [Accepted: 08/23/2013] [Indexed: 01/06/2023] Open
Abstract
The normal ANK protein has a strong influence on anti-calcification. It is known that TGF-β1 is also able to induce extracellular inorganic pyrophosphate (ePPi) elaboration via the TGF-β1-induced ank gene expression and the mitogen-activated protein kinase (MAPK) signaling acts as a downstream effector of TGF-β1. We hypothesized that the expression of the ank gene is regulated by mechanics through TGF-β1-p38 pathway. In this study, we investigated the mechanism of short-time mechanical tension-induced ank gene expression. We found that the continuous cyclic mechanical tension (CCMT) increased the ank gene expression in the endplate chondrocytes, and there was an increase in the TGF-β1 expression after CCMT stimulation. The ank gene expression significantly increased when treated by TGF-β1 in a dose-dependent manner and decreased when treated by SB431542 (ALK inhibitor) in a dose-dependent manner. Our study results indicate that CCMT-induced ank gene expressions may be regulated by TGF-β1 and p38 MAPK pathway.
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Xu HG, Li ZR, Wang H, Liu P, Xiang SN, Wang CD, Zhang XL. Intermittent cyclic mechanical tension-induced down-regulation of ectonucleotide pyrophosphatase phosphodiesterase 1 gene expression is mainly dependent on TGF-β1 in end-plate chondrocytes. Orthop Surg 2013; 5:40-5. [PMID: 23420746 DOI: 10.1111/os.12028] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Accepted: 11/24/2012] [Indexed: 12/12/2022] Open
Abstract
OBJECTIVE To investigate the relationship between ectonucleotide pyrophosphatase phosphodiesterase-1(ENPP-1) expression and transforming growth factor beta 1 (TGF-β1) of end-plate chondrocytes after stimulation with intermittent cyclic mechanical tension (ICMT) by using an FX-4000T Flexercell Tension Plus unit. METHODS Rat end-plate chondrocytes were cultured and ICMT (strain at 0.5 Hz sinusoidal curve at 10% elongation) applied for 7 days for 4 h/day and cultured for a further 2 days. End-plate chondrocytes were also exposed to 10 ng/mL of TGF-β1. Then, using small interfering RNA technology, small interfering TGF-β1 (siTGF-β1) was transfected. Expression of ENPP-1 and TGF-β1 was measured by real-time reverse-transcriptase polymerase chain reaction (RT-PCR) and western blotting. RESULTS Expression of both ENPP-1 and TGF-β1 was up-regulated after ICMT. Both RT-PCR and western blot showed that ENPP-1 expression decreases with siRNA TGF-β1 after 3% elongation 40 min, and cultured for an additional 2 days. CONCLUSION It was found that down-regulation of ENPP-1 gene expression induced by ICMT is likely dependent on TGF-β1 in end-plate chondrocytes.
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Affiliation(s)
- Hong-guang Xu
- Department of Spine Surgery, Yijishan Hospital, Wannan Medical College, Wuhu, Anhui, China.
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Staines KA, Mackenzie NCW, Clarkin CE, Zelenchuk L, Rowe PS, MacRae VE, Farquharson C. MEPE is a novel regulator of growth plate cartilage mineralization. Bone 2012; 51:418-30. [PMID: 22766095 PMCID: PMC3427007 DOI: 10.1016/j.bone.2012.06.022] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Revised: 06/21/2012] [Accepted: 06/23/2012] [Indexed: 01/24/2023]
Abstract
Matrix extracellular phosphoglycoprotein (MEPE) belongs to the SIBLING protein family which play key roles in biomineralization. Although the growth plates of MEPE-overexpressing mice display severe morphological disruption, the expression and function of MEPE in growth plate matrix mineralization remains largely undefined. Here we show MEPE and its cleavage product, the acidic serine aspartate-rich MEPE-associated motif (ASARM) peptide, to be localised to the hypertrophic zone of the growth plate. We also demonstrate that the phosphorylated (p)ASARM peptide inhibits ATDC5 chondrocyte matrix mineralization. Stable MEPE-overexpressing ATDC5 cells also had significantly reduced matrix mineralization in comparison to the control cells. Interestingly, we show that the addition of the non-phosphorylated (np)ASARM peptide promoted mineralization in the ATDC5 cells. The peptides and the overexpression of MEPE did not affect the differentiation of the ATDC5 cells. For a more physiologically relevant model, we utilized the metatarsal organ culture model. We show the pASARM peptide to inhibit mineralization at two stages of development, as shown by histological and μCT analysis. Like in the ATDC5 cells, the peptides did not affect the differentiation of the metatarsals indicating that the effects seen on mineralization are direct, as is additionally confirmed by no change in alkaline phosphatase activity or mRNA expression. In the metatarsal organ cultures, the pASARM peptide also reduced endothelial cell markers and vascular endothelial growth factor mRNA expression. Taken together these results show MEPE to be an important regulator of growth plate chondrocyte matrix mineralization through its cleavage to an ASARM peptide.
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Affiliation(s)
- K A Staines
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Easter Bush, Midlothian EH25 9RG, UK.
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Abhishek A, Doherty M. Pathophysiology of articular chondrocalcinosis--role of ANKH. Nat Rev Rheumatol 2010; 7:96-104. [PMID: 21102543 DOI: 10.1038/nrrheum.2010.182] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Calcium pyrophosphate (CPP) crystal deposition (CPPD) is associated with ageing and osteoarthritis, and with uncommon disorders such as hyperparathyroidism, hypomagnesemia, hemochromatosis and hypophosphatasia. Elevated levels of synovial fluid pyrophosphate promote CPP crystal formation. This extracellular pyrophosphate originates either from the breakdown of nucleotide triphosphates by plasma-cell membrane glycoprotein 1 (PC-1) or from pyrophosphate transport by the transmembrane protein progressive ankylosis protein homolog (ANK). Although the etiology of apparent sporadic CPPD is not well-established, mutations in the ANK human gene (ANKH) have been shown to cause familial CPPD. In this Review, the key regulators of pyrophosphate metabolism and factors that lead to high extracellular pyrophosphate levels are described. Particular emphasis is placed on the mechanisms by which mutations in ANKH cause CPPD and the clinical phenotype of these mutations is discussed. Cartilage factors predisposing to CPPD and CPP-crystal-induced inflammation and current treatment options for the management of CPPD are also described.
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Affiliation(s)
- Abhishek Abhishek
- Division of Academic Rheumatology, Clinical Sciences Building, City Hospital Nottingham, Hucknall Road, Nottingham NG51PB, UK.
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Skubutyte R, Markova D, Freeman TA, Anderson DG, Dion AS, Williams CJ, Shapiro IM, Risbud MV. Hypoxia-inducible factor regulation of ANK expression in nucleus pulposus cells: possible implications in controlling dystrophic mineralization in the intervertebral disc. ACTA ACUST UNITED AC 2010; 62:2707-15. [PMID: 20496369 DOI: 10.1002/art.27558] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
OBJECTIVE Since nucleus pulposus cells reside under conditions of hypoxia, we determined if the expression of ANK, a pyrophosphate transporter, is regulated by the hypoxia-inducible factor (HIF) proteins. METHODS Quantitative reverse transcription-polymerase chain reaction and Western blot analyses were used to measure ANK expression in nucleus pulposus cells from rats and humans. Transfections were performed to determine the effect of HIF-1/2 on ANK promoter activity. RESULTS ANK was expressed in embryonic and mature rat discs. Oxygen-dependent changes in ANK expression in nucleus pulposus cells were minimal. However, silencing of HIF-1α and HIF-2α resulted in increased ANK expression and up-regulation of promoter activity. HIF-mediated suppression of ANK was validated by measuring promoter activity in HIF-1β-null embryonic fibroblasts. Under conditions of hypoxia, there was induction of promoter activity in the null cells as compared with the wild-type cells. Overexpression of HIF-1α and HIF-2α in nucleus pulposus cells resulted in a significant suppression of ANK promoter activity. Since the ANK promoter contains 2 hypoxia-responsive elements (HREs), we performed site-directed mutagenesis and measured promoter activity. We found that HIF-1 can bind to either of the HREs and can suppress promoter activity; in contrast, HIF-2 was required to bind to both HREs in order to suppress activity. Finally, analysis of human nucleus pulposus tissue showed that while ANK was expressed in normal tissue, there was increased expression of ANK along with alkaline phosphatase in the degenerated state. CONCLUSION Both HIF-1 and HIF-2 serve as negative regulators of ANK expression in the disc. We propose that baseline expression of ANK in the disc serves to prevent mineral formation under physiologic conditions.
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Bertrand J, Cromme C, Umlauf D, Frank S, Pap T. Molecular mechanisms of cartilage remodelling in osteoarthritis. Int J Biochem Cell Biol 2010; 42:1594-601. [PMID: 20603225 DOI: 10.1016/j.biocel.2010.06.022] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2010] [Revised: 06/24/2010] [Accepted: 06/25/2010] [Indexed: 01/12/2023]
Abstract
Osteoarthritis (OA) is a degenerative joint disease that is characterized primarily by progressive breakdown of articular cartilage. The loss of proteoglycans, the mineralization of the extracellular matrix (ECM) and the hypertrophic differentiation of the chondrocytes constitute hallmarks of the disease. The pathogenesis of OA includes several pathways, which in single are very well investigated and partly understood, but in their complex interplay remain mainly unclear. This review summarises recent data on the underlying mechanisms, specifically with respect to cell-matrix interactions and cartilage mineralization. It points out why these findings are of importance for future OA research and for the development of novel therapeutic strategies to treat OA.
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Affiliation(s)
- Jessica Bertrand
- Institute of Experimental Musculoskeletal Medicine IEMM, University Hospital Muenster, Muenster, Germany
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Oca P, Zaka R, Dion AS, Freeman TA, Williams CJ. Phosphate and calcium are required for TGFβ-mediated stimulation of ANK expression and function during chondrogenesis. J Cell Physiol 2010; 224:540-8. [DOI: 10.1002/jcp.22155] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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Cailotto F, Sebillaud S, Netter P, Jouzeau JY, Bianchi A. The inorganic pyrophosphate transporter ANK preserves the differentiated phenotype of articular chondrocyte. J Biol Chem 2010; 285:10572-82. [PMID: 20133941 DOI: 10.1074/jbc.m109.050534] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The differentiated phenotype of chondrocyte is lost in pathological situations and after interleukin (IL)-1beta challenge. Wnt proteins and the inorganic pyrophosphate (PP(i)) transporter Ank regulate the differentiation process in many cell types. We investigated the possible contribution of Ank and/or PP(i) to the maintenance of the differentiated chondrocyte phenotype with special care to Wnt signaling. Primary articular chondrocytes lost their phenotype upon IL-1beta challenge, with cessation of type II collagen and Sox-9 expression. Ank expression and PP(i) transport were strongly reduced by IL-1beta, whereas Wnt-5a was the only Wnt protein increased. Transient overexpression of Ank counteracted most of IL-1beta effects on Type II collagen, Sox-9, and Wnt-5a expression. When resting chondrocytes were transfected with a siRNA against Ank, this reproduced the phenotype induced by IL-1beta. In both cases, no markers for hypertrophic chondrocytes were detected. The conditioned supernatant from chondrocytes knocked-down for Ank contained Wnt-5a, which activated Tcf/Lef reporter plasmids and promoted translocation of beta-catenin into the nucleus without activating the c-Jun N-terminal kinase (JNK) pathway. Supplementation with PP(i) compensated for most effects of Ank deficiency on Type II collagen, Sox-9, and Wnt-5 expression, both in IL-1beta and Ank knock-down conditions. Phenotype changes induced by IL-1beta were also supported by activation of the JNK pathway, but this latter was not sensitive to PP(i) supplementation. Altogether our data demonstrate that the transport of PP(i) by ANK contributed to the maintenance of the differentiated phenotype of chondrocyte by controlling the canonical Wnt pathway in a Wnt-5a-dependent manner.
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Affiliation(s)
- Frederic Cailotto
- Laboratoire de Physiopathologie, Pharmacologie et Ingénierie Articulaires, UMR 7561 CNRS-Nancy-Université, Avenue de la Forêt de Haye, BP184, 54505 Vandoeuvre-Lès-Nancy, France.
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Oxygen tension regulates the expression of ANK (progressive ankylosis) in an HIF-1-dependent manner in growth plate chondrocytes. J Bone Miner Res 2009; 24:1869-78. [PMID: 19419319 PMCID: PMC2765931 DOI: 10.1359/jbmr.090512] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The proximal promoter region of ANK, a gene that codes for a protein that regulates the transport of inorganic pyrophosphate, contains two hypoxia responsive elements (HREs); therefore, we studied the expression and function of ANK at different oxygen tensions. ATDC5 and N1511 clonal chondrocytic cells were cultured in either hypoxia (2% O(2)) or normoxia (21% O(2)). Transcript and protein levels of ANK were depressed in hypoxic conditions, as were levels of extracellular pyrophosphate (ePPi). To determine whether HIF-1 was involved in the oxemic response, Hif-1alpha knockdown cells were exposed to varying oxygen conditions and ANK expression was assessed. Knockdown of Hif-1alpha resulted in low levels of expression of ANK in hypoxia and normoxia. Chromatin immunoprecipitation (ChIP) assays explored the binding of Hif-1alpha to ANK HREs and showed that Hif-1alpha is able to bind to the HREs of ANK more avidly in normoxia than in hypoxia. Furthermore, functional studies of Hif-1alpha activity using luciferase reporter assays of wildtype and mutagenized HREs showed that only HRE-1 binds Hif-1alpha in normoxia. Expression of ANK in growth plate and articular cartilage was low in hypoxic regions of the tissues, and higher levels of ANK expression were observed in the synovium and meniscus in regions that have a normally higher oxygen tension. The data suggest that ANK expression and function in vitro and in vivo are repressed in hypoxic environments and that the effect is regulated by HIF-1.
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Abstract
PURPOSE OF REVIEW Calcium pyrophosphate dihydrate and basic calcium phosphate crystals are the two most common calcium-containing crystals involved in rheumatic diseases. Recent literature concerning their role in the pathogenesis of osteoarthritis is reviewed. RECENT FINDINGS In some instances, these calcium crystals might worsen osteoarthritis cartilage destruction. Laboratory investigations have identified determinants of cartilage calcification, especially a better characterization of matrix vesicle content and a better understanding of the regulation of inorganic pyrophosphate and phosphate concentration. In-vitro studies have highlighted new pathogenic mechanisms of calcium crystal-induced cell activation. Several intracellular signalling pathways are activated by calcium crystals. Recent studies suggested the implication of the inflammasome complex and a pivotal role for IL-1 in pseudogout attacks and chondrocyte apoptosis in basic calcium phosphate crystal-related arthropathies. SUMMARY Animal models of osteoarthritis and in-vitro studies using calcium pyrophosphate dihydrate and basic calcium phosphate crystals will improve our knowledge of these common crystals and could suggest new targets for drugs, as these common diseases are 'orphan' with respect to therapy.
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15
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Cailotto F, Bianchi A, Sebillaud S, Venkatesan N, Moulin D, Jouzeau JY, Netter P. Inorganic pyrophosphate generation by transforming growth factor-beta-1 is mainly dependent on ANK induction by Ras/Raf-1/extracellular signal-regulated kinase pathways in chondrocytes. Arthritis Res Ther 2008; 9:R122. [PMID: 18034874 PMCID: PMC2246241 DOI: 10.1186/ar2330] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2007] [Revised: 11/12/2007] [Accepted: 11/22/2007] [Indexed: 12/01/2022] Open
Abstract
ANK is a multipass transmembrane protein transporter thought to play a role in the export of intracellular inorganic pyrophosphate and so to contribute to the pathophysiology of chondrocalcinosis. As transforming growth factor-beta-1 (TGF-β1) was shown to favor calcium pyrophosphate dihydrate deposition, we investigated the contribution of ANK to the production of extracellular inorganic pyrophosphate (ePPi) by chondrocytes and the signaling pathways involved in the regulation of Ank expression by TGF-β1. Chondrocytes were exposed to 10 ng/mL of TGF-β1, and Ank expression was measured by quantitative polymerase chain reaction and Western blot. ePPi was quantified in cell supernatants. RNA silencing was used to define the respective roles of Ank and PC-1 in TGF-β1-induced ePPi generation. Finally, selective kinase inhibitors and dominant-negative/overexpression plasmid strategies were used to explore the contribution of several signaling pathways to Ank induction by TGF-β1. TGF-β1 strongly increased Ank expression at the mRNA and protein levels, as well as ePPi production. Using small interfering RNA technology, we showed that Ank contributed approximately 60% and PC-1 nearly 20% to TGF-β1-induced ePPi generation. Induction of Ank by TGF-β1 required activation of the extracellular signal-regulated kinase (ERK) pathway but not of p38-mitogen-activated protein kinase or of protein kinase A. In line with the general protein kinase C (PKC) inhibitor calphostin C, Gö6976 (a Ca2+-dependent PKC inhibitor) diminished TGF-β1-induced Ank expression by 60%, whereas a 10% inhibition was observed with rottlerin (a PKCδ inhibitor). These data suggest a regulatory role for calcium in TGF-β1-induced Ank expression. Finally, we demonstrated that the stimulatory effect of TGF-β1 on Ank expression was inhibited by the suppression of the Ras/Raf-1 pathway, while being enhanced by their constitutive activation. Transient overexpression of Smad 7, an inhibitory Smad, failed to affect the inducing effect of TGF-β1 on Ank mRNA level. These data show that TGF-β1 increases ePPi levels, mainly by the induction of the Ank gene, which requires activation of Ras, Raf-1, ERK, and Ca2+-dependent PKC pathways in chondrocytes.
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Affiliation(s)
- Frederic Cailotto
- UMR 7561 CNRS-Nancy-Université, Laboratoire de Physiopathologie et Pharmacologie Articulaires, France.
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16
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The inorganic phosphate/inorganic pyrophosphate axis in the mineralization of cartilage and bone. ACTA ACUST UNITED AC 2007. [DOI: 10.1097/bco.0b013e328285dffc] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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17
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Hatch NE. Potential role of PC-1 expression and pyrophosphate elaboration in the molecular etiology of the FGFR-associated craniosynostosis syndromes. Orthod Craniofac Res 2007; 10:53-8. [PMID: 17552941 DOI: 10.1111/j.1601-6343.2007.00387.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
BACKGROUND Fibroblast growth factor/fibroblast growth factor receptor (FGF/FGFR) signaling is associated with the aberrant mineralization phenotype of the craniosynostosis syndromes. One critical aspect of mineralization involves the elaboration and transport of pyrophosphate into the extracellular matrix with subsequent enzymatic hydrolysis into phosphate. We have previously shown that FGF2 up-regulates expression of the pyrophosphate generating enzyme, PC-1, and the pyrophosphate channel, ANK, while down-regulating expression of the pyrophosphate hydrolyzing enzyme, tissue non-specific alkaline phosphatase in pre-osteoblastic, MC3T3E1(C4) cells. These results suggest that FGF/FGFR signaling may affect mineralization via changes in the elaboration and metabolism of pyrophosphate. OBJECTIVES We are currently conducting experiments towards a more systematic analysis of PC-1 expression in osteoblastic cells, in order to more clearly elucidate the significance of pyrophosphate elaboration in the process of normal bone mineralization and in the molecular etiology of the FGFR-associated craniosynostosis syndromes. DESIGN Towards this goal we have constructed a PC-1 gene promoter/firefly luciferase reporter construct, in order to more directly investigate the regulation of PC-1 by FGF/FGFR signaling in osteoblastic and non-osteoblastic cells. RESULTS AND CONCLUSIONS Preliminary results confirm that FGF/FGFR signaling, either via treatment with FGF2 or via expression of a Crouzon syndrome-associated mutant FGFR2, induces PC-1 promoter activity in osteoblastic cells in culture. This appears to be a cell type specific phenomenon. These results suggest that the expression of PC-1 downstream of FGF signaling is an integral aspect of osteoblastic function, and that pyrophosphate elaboration may play a significant role in the pathology of craniosynostosis.
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Affiliation(s)
- Nan E Hatch
- Department of Orthodontics and Pediatric Dentistry, School of Dentistry, University of Michigan, Ann Arbor, MI 48109, USA.
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18
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Zaka R, Stokes D, Dion AS, Kusnierz A, Han F, Williams CJ. P5L mutation in Ank results in an increase in extracellular inorganic pyrophosphate during proliferation and nonmineralizing hypertrophy in stably transduced ATDC5 cells. Arthritis Res Ther 2007; 8:R164. [PMID: 17067391 PMCID: PMC1794507 DOI: 10.1186/ar2072] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2006] [Revised: 10/05/2006] [Accepted: 10/26/2006] [Indexed: 11/29/2022] Open
Abstract
Ank is a multipass transmembrane protein that regulates the cellular transport of inorganic pyrophosphate. In the progressive ankylosis (ank) mouse, a premature termination mutation at glutamic acid 440 results in a phenotype characterized by inappropriate deposition of basic calcium phosphate crystals in skeletal tissues. Mutations in the amino terminus of ANKH, the human homolog of Ank, result in familial calcium pyrophosphate dihydrate deposition disease. It has been hypothesized that these mutations result in a gain-of-function with respect to the elaboration of extracellular inorganic pyrophosphate. To explore this issue in a mineralization-competent system, we stably transduced ATDC5 cells with wild-type Ank as well as with familial chondrocalcinosis-causing Ank mutations. We evaluated the elaboration of inorganic pyrophosphate, the activity of pyrophosphate-modulating enzymes, and the mineralization in the transduced cells. Expression of transduced protein was confirmed by quantitative real-time PCR and by ELISA. Levels of inorganic pyrophosphate were measured, as were the activities of nucleotide pyrophosphatase phosphodiesterase and alkaline phosphatase. We also evaluated the expression of markers of chondrocyte maturation and the nature of the mineralization phase elaborated by transduced cells. The cell line expressing the proline to leucine mutation at position 5 (P5L) consistently displayed higher levels of extracellular inorganic pyrophosphate and higher phosphodiesterase activity than the other transduced lines. During hypertrophy, however, extracellular inorganic pyrophosphate levels were modulated by alkaline phosphatase activity in this cell system, resulting in the deposition of basic calcium phosphate crystals only in all transduced cell lines. Cells overexpressing wild-type Ank displayed a higher level of expression of type X collagen than cells transduced with mutant Ank. Other markers of hypertrophy and terminal differentiation, such as alkaline phosphatase, osteopontin, and runx2, were not significantly different in cells expressing wild-type or mutant Ank in comparison with cells transduced with an empty vector or with untransduced cells. These results suggest that the P5L Ank mutant is capable of demonstrating a gain-of-function with respect to extracellular inorganic pyrophosphate elaboration, but this effect is modified by high levels of expression of alkaline phosphatase in ATDC5 cells during hypertrophy and terminal differentiation, resulting in the deposition of basic calcium phosphate crystals.
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Affiliation(s)
- Raihana Zaka
- Division of Rheumatology, Department of Medicine, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - David Stokes
- Division of Rheumatology, Department of Medicine, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Arnold S Dion
- College of Graduate Studies, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Anna Kusnierz
- Division of Rheumatology, Department of Medicine, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Fei Han
- Division of Rheumatology, Department of Medicine, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Charlene J Williams
- Division of Rheumatology, Department of Medicine, Thomas Jefferson University, Philadelphia, PA 19107, USA
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19
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Gurley KA, Chen H, Guenther C, Nguyen ET, Rountree RB, Schoor M, Kingsley DM. Mineral formation in joints caused by complete or joint-specific loss of ANK function. J Bone Miner Res 2006; 21:1238-47. [PMID: 16869722 DOI: 10.1359/jbmr.060515] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
UNLABELLED To reveal the ANK complete loss of function phenotype in mice, we generated conditional and null alleles. Mice homozygous for the null allele exhibited widespread joint mineralization, similar in severity to animals harboring the original ank allele. A delayed yet similar phenotype was observed in mice with joint-specific loss of ANK function. INTRODUCTION The ANK pyrophosphate regulator was originally identified and proposed to play a key role in articular cartilage maintenance based on a single spontaneous mouse mutation (ank) that causes severe generalized arthritis. A number of human mutations have subsequently been reported in the human ortholog (ANKH), some of which produce skull and long bone defects with no apparent defects in joints or articular cartilage. None of the currently known mouse or human mutations clearly eliminate the function of the endogenous gene. MATERIALS AND METHODS Two new Ank alleles were generated using homologous recombination in mouse embryonic stem (ES) cells. Joint range of motion assays and muCT studies were used to quantitatively assess phenotypic severity in wildtype, heterozygous, and homozygous mice carrying either the null (Anknull) or original (Ankank) allele. A Gdf5-Cre expressing line was crossed to mice harboring the conditional (Ankfloxp) allele to eliminate ANK function specifically in the joints. Histological stains and beta-galactosidase (LACZ) activity were used to determine the correlation between local loss of ANK function and defective joint phenotypes. RESULTS Anknull/Anknull mice develop severe ectopic postnatal crystal deposition in almost every joint of the body, leading to eventual joint fusion and loss of mobility. The severity of phenotype in these mice is indistinguishable from that of Ankank/Ankank mice. In addition, despite the widespread expression of Ank in many tissues, the specific deletion of Ank in joints also produces joint mineralization and ankylosis. CONCLUSIONS These studies show that ANK function is required locally in joints to inhibit mineral formation and that the Ank gene plays a key role in postnatal maintenance of joint mobility and function.
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Affiliation(s)
- Kyle A Gurley
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
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20
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Abstract
PURPOSE OF REVIEW Among the myriad of players in the calcification of cartilage, ANK is a relatively new entrant. It is a multipass transmembrane protein that regulates the transport of inorganic pyrophosphate between the cell and the extracellular space. Mutations in ANK result in two distinct calcification disorders: craniometaphyseal dysplasia and familial calcium pyrophosphate dihydrate deposition disease. The purpose of this review is to highlight recent work on the role of ANK in physiological and pathological calcification of articular and growth plate cartilage. RECENT FINDINGS New information on the function of ANK suggests that the protein is part of a constellation of critical components that interact to regulate the elaboration of inorganic pyrophosphate. In addition to ANK, these components include alkaline phosphatase, the ectoenzyme PC-1, and osteopontin. ANK expression is also regulated by a variety of growth factors and cytokines that may further affect the transport of inorganic pyrophosphate and may be particularly relevant to the increased levels of expression of ANK in cartilage from chondrocalcinosis and osteoarthritis patients. SUMMARY Additional studies will be required to understand the contribution of ANK in shaping the fine balance of components necessary for crystal deposition in degenerating articular cartilage. Furthermore, the precise role of inherited mutations in ANK on the elaboration of inorganic pyrophosphate, and the ultimate deposition of either basic calcium phosphate or calcium pyrophosphate dihydrate crystals, remains unclear.
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Affiliation(s)
- Raihana Zaka
- Department of Medicine/Division of Rheumatology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
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21
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McKee MD, Addison WN, Kaartinen MT. Hierarchies of Extracellular Matrix and Mineral Organization in Bone of the Craniofacial Complex and Skeleton. Cells Tissues Organs 2006; 181:176-88. [PMID: 16612083 DOI: 10.1159/000091379] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Structural hierarchies are common in biologic systems and are particularly evident in biomineralized structures. In the craniofacial complex and skeleton of vertebrates, extracellular matrix and mineral of bone are structurally ordered at many dimensional scales from the macro level to the nano level. Indeed, the nanocomposite texture of bone, with nanocrystals of apatitic mineral embedded within a crosslinked matrix of fibrillar and nonfibrillar proteins, imparts to bone the very mechanical properties and toughness it needs to function in vital organ protection, musculoskeletal movement and mastication. This article focuses on how hierarchies of extracellular matrix protein organization influence bone cell behavior, tissue architecture and mineralization. Additional attention is given to recent work on the molecular determinants of mineral induction in bone, and how the mineralization process is subsequently regulated by inhibitory proteins.
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Affiliation(s)
- M D McKee
- Faculty of Dentistry, McGill University, Montreal, QC, Canada.
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22
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Nakamura Y, Nawata M, Wakitani S. Expression profiles and functional analyses of Wnt-related genes in human joint disorders. THE AMERICAN JOURNAL OF PATHOLOGY 2005; 167:97-105. [PMID: 15972956 PMCID: PMC1603448 DOI: 10.1016/s0002-9440(10)62957-4] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Rheumatoid arthritis (RA) and osteoarthritis (OA) are joint disorders that cause major public health problems. Previous studies of the etiology of RA and OA have implicated Wnt genes, although the exact nature of their involvement remains unclear. To further clarify the relationship between RA, OA, and the Wnt gene family, gene expression analyses were performed on articular cartilage, bone, and synovial tissues in knee joints taken from RA, OA, and nor-mal/control patients. Cytokine assays were also performed in cells transfected with Wnt-7b, a member of the gene family most closely linked to RA and OA. Of the human Wnt genes, real-time PCR analysis revealed significant up-regulation of Wnt-7b in OA cartilage and RA synovium. In situ hybridization and immunohistochemistry also revealed that Wnt-7b was present in articular cartilage, bone, and synovium of RA samples and in osteophytes, articular cartilage, bone marrow, and synovium of OA samples. The levels of the cytokines tumor necrosis factor-alpha, interleukin-1beta, and interleukin-6 were significantly increased in RA synovium and Wnt-7b-transfected normal synovial cells when compared with normal samples. These results point to the potential involvement of Wnt signaling in the pathobiology of both RA and OA.
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Affiliation(s)
- Yukio Nakamura
- Department of Orthopaedic Surgery, Shinshu University School of Medicine, Asahi 3-1-1, Matsumoto, 390-8621, Japan
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23
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Abstract
PURPOSE OF REVIEW Our understanding of the causation of the chondrocalcinosis and other disorders characterized by ectopic mineralization is rapidly increasing, and genetic studies have contributed substantially to recent major advances in the field. This review will discuss what is known about the genetics of chondrocalcinosis and what we have learned from genetic studies to date. RECENT FINDINGS Chondrocalcinosis is one of a family of conditions associated with ectopic mineralization. This family also includes disorders of mineralization of bone and spinal and other ligaments, and vascular calcification. There has been increasing evidence of the key role of transport and metabolism of inorganic pyrophosphate (PPi) in control of mineralization, and as the likely explanation for the association of a variety of genetic variants with chondrocalcinosis and ectopic mineralization elsewhere. This may be an overly simplistic view of this family of conditions, with recent evidence suggesting that, for example, ANKH variants may not all predispose to chondrocalcinosis by effects on PPi transport, but may also influence chondrocyte maturation. SUMMARY Understanding the control of the process of mineralization and its tissue specificity are important steps in the search for rational therapies for these conditions.
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Affiliation(s)
- Yun Zhang
- Institute of Musculoskeletal Sciences, University of Oxford, Botnar Research Centre, Nuffield Orthopaedic Centre, Headington, Oxford, UK
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24
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Wang W, Xu J, Du B, Kirsch T. Role of the progressive ankylosis gene (ank) in cartilage mineralization. Mol Cell Biol 2005; 25:312-23. [PMID: 15601852 PMCID: PMC538760 DOI: 10.1128/mcb.25.1.312-323.2005] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2004] [Revised: 07/07/2004] [Accepted: 10/01/2004] [Indexed: 11/20/2022] Open
Abstract
Mineralization of growth plate cartilage is a critical event during endochondral bone formation, which allows replacement of cartilage by bone. Ankylosis protein (Ank), which transports intracellular inorganic pyrophosphate (PP(i)) to the extracellular milieu, is expressed by hypertrophic and, especially highly, by terminally differentiated mineralizing growth plate chondrocytes. Blocking Ank transport activity or ank expression in terminally differentiated mineralizing growth plate chondrocytes led to increases of intra- and extracellular PP(i) concentrations, decreases of alkaline phosphatase (APase) expression and activity, and inhibition of mineralization, whereas treatment of these cells with the APase inhibitor levamisole led to an increase of extracellular PP(i) concentration and inhibition of mineralization. Ank-overexpressing hypertrophic nonmineralizing growth plate chondrocytes showed decreased intra- and extracellular PP(i) levels; increased mineralization-related gene expression of APase, type I collagen, and osteocalcin; increased APase activity; and mineralization. Treatment of Ank-expressing growth plate chondrocytes with a phosphate transport blocker (phosphonoformic acid [PFA]) inhibited uptake of inorganic phosphate (P(i)) and gene expression of the type III Na(+)/P(i) cotransporters Pit-1 and Pit-2. Furthermore, PFA or levamisole treatment of Ank-overexpressing hypertrophic chondrocytes inhibited APase expression and activity and subsequent mineralization. In conclusion, increased Ank activity results in elevated intracellular PP(i) transport to the extracellular milieu, initial hydrolysis of PP(i) to P(i), P(i)-mediated upregulation of APase gene expression and activity, further hydrolysis and removal of the mineralization inhibitor PP(i), and subsequent mineralization.
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Affiliation(s)
- Wei Wang
- Department of Orthopaedics, University of Maryland School of Medicine, 22 South Greene Street, Baltimore, MD 21201, USA
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25
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Hatch NE, Nociti F, Swanson E, Bothwell M, Somerman M. FGF2 alters expression of the pyrophosphate/phosphate regulating proteins, PC-1, ANK and TNAP, in the calvarial osteoblastic cell line, MC3T3E1(C4). Connect Tissue Res 2005; 46:184-92. [PMID: 16546821 DOI: 10.1080/03008200500237203] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Fibroblast growth factor/fibroblast growth factor receptor (FGF/FGFR) signaling has been linked to the aberrant mineralization phenotype of craniosynostosis syndromes. One critical aspect of mineralization involves the elaboration and transport of pyrophosphate into the extracellular matrix with subsequent enzymatic hydrolysis into phosphate. Altered expression of the pyrophosphate elaborating factors, TNAP (tissue nonspecific alkaline phosphatase), PC-1, and ANK, downstream of FGF/FGFR signaling may provide a potential mechanism for the craniosynostosis phenotype. As an initial step toward testing this hypothesis, we confirmed that ANK mRNA is upregulated during osteoblast differentiation in culture. Subsequently, the effect of FGF2 treatment on expression of PC-1, ANK, and TNAP in the calvarial osteoblastic cell line, MC3T3E1(C4), was investigated. FGF2 specifically induced expression of PC-1 and ANK while inhibiting expression of TNAP, at both mRNA and protein levels. Concordant with these changes in gene expression, FGF2 inhibited mineralization. These results suggest that FGF/FGFR signaling may affect mineralization via changes in the elaboration and metabolism of pyrophosphate.
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Affiliation(s)
- Nan E Hatch
- Department of Physiology and Biophysics, University of Washington, Seattle, Washington 98195, USA.
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26
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Ohno S, Tanaka N, Ueki M, Honda K, Tanimoto K, Yoneno K, Ohno-Nakahara M, Fujimoto K, Kato Y, Tanne K. Mechanical regulation of terminal chondrocyte differentiation via RGD-CAP/beta ig-h3 induced by TGF-beta. Connect Tissue Res 2005; 46:227-34. [PMID: 16546826 DOI: 10.1080/03008200500346111] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
RGD-CAP (beta ig-h3), initially cloned as a transforming growth factor (TGF)-beta inducible gene in human lung adenocarcinoma cells, was demonstrated to have a negative regulatory function in mineralization in hypertrophic chondrocytes, and the expression was shown to be associated with mechanical stimulation. We hypothesized that mechanical stimulation may regulate the terminal chondrocyte differentiation through the TGF-beta pathway by enhancing the RGD-CAP expression. To test this hypothesis, we investigated the effects of mechanical strain on the terminal differentiation and mineralization of growth-plate chondrocytes and assessed the mechanical regulation of TGF-ss and RGD-CAP expression. A cyclic mechanical strain of 12% elongation was applied to the cultured pre-hypertrophic chondrocytes isolated from the rib cartilage of 4-week-old male rats at 30 cycles/min (loading and relaxation on every alternate second). The terminal differentiation and mineralization of chondrocytes were assessed by alkaline phosphatase (ALP) activity assay and alizarin red staining. The gene expressions of TGF-ss and RGD-CAP, as well as chondrocytic terminal differentiation markers such as type X collagen and ALP, were examined with real-time RT-PCR. Cyclic mechanical strain decreased the ALP activity and intensity of alizarin red staining in pre-hypertrophic chondrocytes, as well as the gene expressions of type X collagen and ALP. TGF-ss and RGD-CAP were upregulated in the pre-hypertrophic chondrocytes subjected to mechanical strain, whereas the level of PTHrP receptor mRNA was not affected by the mechanical strain. The neutralizing antibody for TGF-ss suppressed the reduction of the mineralization of chondrocyte cultures with the downregulation of RGD-CAP. These results suggest that mechanical strain negatively regulates the terminal differentiation of chondrocytes through the signal pathway of TGF-ss with the induction of RGD-CAP.
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Affiliation(s)
- Shigeru Ohno
- Department of Orthodontics, Hiroshima University Graduate School of Biomedical Sciences, Hiroshima, Japan.
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27
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Ea HK, Lioté F. Calcium pyrophosphate dihydrate and basic calcium phosphate crystal-induced arthropathies: update on pathogenesis, clinical features, and therapy. Curr Rheumatol Rep 2004; 6:221-7. [PMID: 15134602 DOI: 10.1007/s11926-004-0072-6] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Calcium-containing crystals are the most common class for the osteoarthritic joint. They are responsible for acute periarthritis and destructive arthropathies, and for tissue deposits mimicking tumor-like masses. These crystals encompassed mainly calcium pyrophosphate dihydrate and basic calcium phosphate crystals, with the latter being related to hydroxyapatite, carbonate-substituted apatite, and octacalcium phosphate. Calcification deposit mechanisms will be reviewed with respect to extracellular inorganic pyrophosphate dysregulation mainly caused by modulation of specific membrane channel disorders. Genetic defects have been extensively studied and identified mutation of specific genes such as ANKH and COL. Pathogenesis of crystal-induced inflammation is related to synovial tissue and direct cartilage activation. Besides classical knee or wrist pseudogout attacks or Milwaukee shoulder arthropathies, clinicians should be aware of other specific common presentations, such as erosive calcifications, spinal cord compression by intraspinal masses, ligamentum flavum calcification, or atypical calcified tophus. Promising clinical results for preventing calcium crystal deposits and cartilage degradation are lacking. Practical imaging tools are needed to monitor reduction of calcification of fibrocartilage and articular cartilage as markers of drug efficacy.
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Affiliation(s)
- Hang-Korng Ea
- Inserm U606 Fédération de Rhumatologie, Hôpital Lariboisière, 2 rue Ambroise Paré, F75475 Paris Cedex 10, France
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Timms AE, Zhang Y, Bradbury L, Wordsworth BP, Brown MA. Investigation of the role of ANKH in ankylosing spondylitis. ACTA ACUST UNITED AC 2003; 48:2898-902. [PMID: 14558096 DOI: 10.1002/art.11258] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
OBJECTIVE The ank/ank mouse develops a phenotype similar to ankylosing spondylitis (AS) in humans. ANKH, the human homolog of the mutated gene in the ank/ank mouse, has been implicated in familial autosomal-dominant chondrocalcinosis and autosomal-dominant craniometaphyseal dysplasia. This study was undertaken to investigate the role of ANKH in susceptibility to and clinical manifestations of AS. METHODS Sequence variants were identified by genomic sequencing of the 12 ANKH exons and their flanking splice sites in 48 AS patients; variants were then screened in 233 patients and 478 controls. Linkage to the ANKH locus was assessed in 185 affected-sibling-pair families. RESULTS Five single-nucleotide polymorphisms were identified within the coding region and flanking splice sites. No association between either susceptibility to AS or its clinical manifestations and these novel polymorphisms, or between disease susceptibility and 3 known promoter variants, was seen. No linkage between the ANKH locus and AS was observed. Multipoint exclusion mapping rejected the hypothesis of a locus of a magnitude lambda>/=1.4 (logarithm of odds score <-2) (equivalent to a genetic contribution of >10% to the AS sibling recurrence risk ratio) within this area contributing to AS. CONCLUSION These findings indicate that ANKH is not significantly involved in susceptibility to or clinical manifestations of AS.
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Affiliation(s)
- A E Timms
- Wellcome Trust Centre for Human Genetics, Headington, UK
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29
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Picher M, Graff RD, Lee GM. Extracellular nucleotide metabolism and signaling in the pathophysiology of articular cartilage. ACTA ACUST UNITED AC 2003; 48:2722-36. [PMID: 14558075 DOI: 10.1002/art.11289] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Maryse Picher
- School of Medicine, University of North Carolina, Chapel Hill 27599, USA.
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30
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Yepes M, Moore E, Brown SAN, Hanscom HN, Smith EP, Lawrence DA, Winkles JA. Progressive ankylosis (Ank) protein is expressed by neurons and Ank immunohistochemical reactivity is increased by limbic seizures. J Transl Med 2003; 83:1025-32. [PMID: 12861042 DOI: 10.1097/01.lab.0000075640.49586.e6] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
Ank is a 492-amino acid multipass transmembrane protein involved in the regulation of extracellular inorganic pyrophosphate levels and the control of tissue calcification. Previous Northern blot hybridization experiments revealed that Ank mRNA was expressed in the brain, but there have been no reports describing the anatomical sites or specific cell types in the brain that express Ank protein. In this study, we demonstrate that Ank is expressed primarily in human brain neurons, with the highest levels of expression observed in the thalamus, the III and V cortical layers, the Purkinje cells of the cerebellum, clusters of cells in the dorsal portion of the pons and midbrain, and neurons of the anterior horn of the spinal cord. In primary mouse neuronal cell cultures, Ank is detected on both the cell body and on cell extensions, mainly dendrites. In the rat brain, Ank mRNA is expressed at relatively high levels in the thalamus, midbrain, and spinal cord, and the Ank protein expression pattern is similar to that observed in the human brain. Finally, we observed a significant increase in Ank immunoreactivity in the rat amygdala, the CA-2 and CA-3 layers of the hippocampus, and the cerebral cortex after the induction of seizure activity. Ank regulation of ATP and/or inorganic pyrophosphate release from neurons may function to modulate the membrane excitability and cell death associated with seizure activity.
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Affiliation(s)
- Manuel Yepes
- Departments of Vascular Biology, Jerome H. Holland Laboratory for the Biomedical Sciences, American Red Cross, Rockville, Maryland 20855, USA
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Johnson K, Farley D, Hu SI, Terkeltaub R. One of two chondrocyte-expressed isoforms of cartilage intermediate-layer protein functions as an insulin-like growth factor 1 antagonist. ARTHRITIS AND RHEUMATISM 2003; 48:1302-14. [PMID: 12746903 DOI: 10.1002/art.10927] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE Aging and osteoarthritic (OA) cartilage commonly demonstrate enhanced expression of the large, transforming growth factor beta (TGFbeta)-inducible glycoprotein cartilage intermediate-layer protein (CILP) as well as enhanced extracellular inorganic pyrophosphate (PPi) that promotes the deposition of calcium pyrophosphate dihydrate crystals. In normal chondrocytes, TGFbeta induces elevated chondrocyte extracellular PPi. Insulin-like growth factor 1 (IGF-1) normally blocks this response and reduces extracellular PPi. However, chondrocyte resistance to IGF-1 is observed in OA and aging. Because CILP was reported to chromatographically fractionate with PPi-generating nucleotide pyrophosphatase phosphodiesterase (NPP) activity, it has been broadly assumed that CILP itself has NPP activity. Our objective was to directly define CILP functions and their relationship to IGF-1 in chondrocytes. METHODS Using primary cultures of articular chondrocytes from the knee, we defined the function of the previously described CILP (CILP-1) and of a recently described 50.6% identical protein that we designated the CILP-2 isoform. RESULTS Both CILP isoforms were constitutively expressed by primary cultured articular chondrocytes, but only CILP-1 expression was detectable in cultured knee meniscal cartilage cells. Neither CILP isoform had intrinsic NPP activity. But CILP-1 blocked the ability of IGF-1 to decrease extracellular PPi, an activity specific for the CILP-1 N-terminal domain. The CILP-1 N-terminal domain also suppressed IGF-1-induced (but not TGFbeta-induced) proliferation and sulfated proteoglycan synthesis, and it inhibited ligand-induced IGF-1 receptor autophosphorylation. CONCLUSION Two CILP isoforms are differentially expressed by chondrocytes. Neither CILP isoform exhibits PPi-generating NPP activity. But, increased expression of CILP-1, via N-terminal domain-mediated inhibitory effects of CILP-1 on chondrocyte IGF-1 responsiveness, could impair chondrocyte growth and matrix repair and indirectly promote PPi supersaturation in aging and OA cartilage.
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Affiliation(s)
- Kristen Johnson
- Department of Veterans Affairs Medical Center, San Diego, and University of California, San Diego, CA 92161, USA
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Abstract
Accumulation of excess inorganic pyrophosphate in cartilage matrix leads to calcium pyrophosphate dihydrate crystal deposits. Recent animal and human studies now support a role for physiologic extracellular pyrophosphate levels in preventing ectopic apatite calcification in joints and extracellular tissues. Extracellular pyrophosphate is likely generated by ectoenzymes and/or is a consequence of transport of intracellular pyrophosphate to the extracellular space. Generation of pyrophosphate by chondrocytes is modulated by aging, several soluble growth factors and cytokines, and transglutaminase. The transduction mechanisms involved in regulating pyrophosphate metabolism include protein kinase C and adenylyl cyclase. It appears that regulation of extracellular pyrophosphate levels within a narrow range is complex and necessary for appropriate mineral homeostasis in articular and nonarticular tissues.
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Affiliation(s)
- Lawrence M Ryan
- Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
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Abstract
The crystal deposition arthropathies comprise a host of disorders that may occur idiopathically or as secondary manifestations of associated diseases. Rarely, crystal deposition presents as a familial disorder. Most affected family members display radiographically detectable crystals of calcium pyrophosphate dihydrate in their joint spaces. In genetic studies of familial calcium pyrophosphate dihydrate deposition disease, a region on the short arm of chromosome 5 was found to be genetically linked to the phenotype displayed by several of these families. Among the positional candidates at this locus was ANKH, the human homolog of a gene that is responsible for the phenotype of progressive ankylosis (ank) in the mouse. ANKH codes for a transmembrane protein that appears to regulate the transport of inorganic pyrophosphate. It was analyzed as a potential positional candidate gene for calcium pyrophosphate dihydrate deposition disease, and in several unrelated families, sequence variants were identified that segregated with the calcium pyrophosphate dihydrate deposition disease phenotype among affected members. A discussion of ANKH as the familial calcium pyrophosphate dihydrate deposition disease gene is presented.
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Affiliation(s)
- Charlene J Williams
- Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
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Shum L. TGF-beta regulates Ankexpression. Arthritis Res Ther 2002. [DOI: 10.1186/ar-2002-77150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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