103
|
Zhang D, Schwarz EM, Rosier RN, Zuscik MJ, Puzas JE, O'Keefe RJ. ALK2 functions as a BMP type I receptor and induces Indian hedgehog in chondrocytes during skeletal development. J Bone Miner Res 2003; 18:1593-604. [PMID: 12968668 DOI: 10.1359/jbmr.2003.18.9.1593] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
UNLABELLED Growth plate chondrocytes integrate multiple signals during normal development. The type I BMP receptor ALK2 is expressed in cartilage and expression of constitutively active (CA) ALK2 and other activated type I BMP receptors results in maturation-independent expression of Ihh in chondrocytes in vitro and in vivo. The findings suggest that BMP signaling modulates the Ihh/PTHrP signaling pathway that regulates the rate of chondrocyte differentiation. INTRODUCTION Bone morphogenetic proteins (BMPs) have an important role in vertebrate limb development. The expression of the BMP type I receptors BMPR-IA (ALK3) and BMPR-IB (ALK6) have been more completely characterized in skeletal development than ALK2. METHODS ALK2 expression was examined in vitro in isolated chick chondrocytes and osteoblasts and in vivo in the developing chick limb bud. The effect of overexpression of CA ALK2 and the other type I BMP receptors on the expression of genes involved in chondrocyte maturation was determined. RESULTS ALK2 was expressed in isolated chick osteoblasts and chondrocytes and specifically mediated BMP signaling. In the developing chick limb bud, ALK2 was highly expressed in mesenchymal soft tissues. In skeletal elements, expression was higher in less mature chondrocytes than in chondrocytes undergoing terminal differentiation. CA ALK2 misexpression in vitro enhanced chondrocyte maturation and induced Ihh. Surprisingly, although parathyroid hormone-related peptide (PTHrP) strongly inhibited CA ALK2 mediated chondrocyte differentiation, Ihh expression was minimally decreased. CA ALK2 viral infection in stage 19-23 limbs resulted in cartilage expansion with joint fusion. Enhanced periarticular expression of PTHrP and delayed maturation of the cartilage elements were observed. In the cartilage element, CA ALK2 misexpression precisely colocalized with the expression with Ihh. These findings were most evident in partially infected limbs where normal morphology was maintained. In contrast, BMP-6 had a normal pattern of differentiation-related expression. CA BMPR-IA and CA BMPR-IB overexpression similarly induced Ihh and PTHrP. CONCLUSIONS The findings show that BMP signaling induces Ihh. Although the colocalization of the activated type I receptors and Ihh suggests a direct BMP-mediated signaling event, other indirect mechanisms may also be involved. Thus, while BMPs act directly on chondrocytes to induce maturation, this effect is counterbalanced in vivo by induction of the Ihh/PTHrP signaling loop. The findings suggest that BMPs are integrated into the Ihh/PTHrP signaling loop and that a fine balance of BMP signaling is essential for normal chondrocyte maturation and skeletal development.
Collapse
MESH Headings
- Activin Receptors, Type I/genetics
- Activin Receptors, Type I/metabolism
- Animals
- Animals, Genetically Modified
- Base Sequence
- Bone Development/genetics
- Bone Development/physiology
- Bone Morphogenetic Protein Receptors, Type I
- Cartilage/abnormalities
- Cartilage/embryology
- Cartilage/metabolism
- Cell Differentiation
- Cells, Cultured
- Chick Embryo
- Chondrocytes/cytology
- Chondrocytes/metabolism
- Chondrogenesis
- DNA, Complementary/genetics
- Gene Expression Regulation, Developmental
- Hedgehog Proteins
- In Situ Hybridization
- Parathyroid Hormone-Related Protein/metabolism
- Protein Serine-Threonine Kinases/genetics
- Protein Serine-Threonine Kinases/metabolism
- Proteins
- Receptor, Transforming Growth Factor-beta Type I
- Receptors, Growth Factor/genetics
- Receptors, Growth Factor/metabolism
- Receptors, Transforming Growth Factor beta/genetics
- Receptors, Transforming Growth Factor beta/metabolism
- Signal Transduction
- Trans-Activators/biosynthesis
- Trans-Activators/genetics
- Transfection
Collapse
Affiliation(s)
- Donghui Zhang
- Center for Musculoskeletal Research, University of Rochester, Rochester, New York 14642, USA
| | | | | | | | | | | |
Collapse
|
108
|
Okazaki M, Higuchi Y, Kitamura H. AG-041R stimulates cartilage matrix synthesis without promoting terminal differentiation in rat articular chondrocytes. Osteoarthritis Cartilage 2003; 11:122-32. [PMID: 12554128 DOI: 10.1053/joca.2002.0868] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE AG-041R, a novel indolin-2-one derivative, has recently been demonstrated to induce systemic hyaline cartilage hyperplasia in rats. The aim of this study was to characterize its anabolic actions on chondrocytes. DESIGN Chondrocytes were isolated from knee joints of 5-week-old SD rats. Effects of AG-041R on cartilage matrix synthesis were examined by measuring [(35)S]sulfate incorporation into proteoglycans, Alcian blue staining, and Northern blotting of cartilage matrix genes. ALP activity, mineral deposition and the expression of markers for hypertrophic chondrocytes, were assessed for terminal differentiation of chondrocytes. Roles of endogenous TGF-beta/BMPs and MEK1/Erk signaling in the action of AG-041R were investigated using the neutralizing soluble receptors and the MEK1 inhibitor. RESULTS AG-041R accelerated proteoglycan synthesis assessed by both [(35)S]sulfate incorporation and Alcian blue stainable extracellular matrix accumulation. It also up-regulated the gene expression of type II collagen and aggrecan, as well as tenascin, a marker for articular cartilage. In contrast, AG-041R suppressed ALP activity, mineralization, and the gene expression of type X collagen and Cbfa1, indicating that AG-041R prevents chondrocyte terminal differentiation. AG-041R increased in BMP-2 mRNA, and the neutralizing soluble receptor for BMPs reversed the stimulatory effects of AG-041R on cartilage matrix synthesis. Moreover, AG-041R activated MEK1/Erk pathway, which was revealed to prevent chondrocyte terminal differentiation. CONCLUSION AG-041R stimulates cartilage matrix synthesis without promoting terminal differentiation in rat articular chondrocytes, which is mediated at least in part by endogenous BMPs and Erk. The data demonstrates that AG-041R has a potential to be a useful therapeutic agent for articular cartilage disorders.
Collapse
Affiliation(s)
- M Okazaki
- Fuji Gotemba Research Laboratories, Chugai Pharmaceutical Co., Ltd, 1-135 Komakado, Gotemba, Shizuoka 412-8513, Japan.
| | | | | |
Collapse
|
110
|
Ehtesham N, Cantor RM, King LM, Reinker K, Powell BR, Shanske A, Unger S, Rimoin DL, Cohn DH. Evidence that Smith-McCort dysplasia and Dyggve-Melchior-Clausen dysplasia are allelic disorders that result from mutations in a gene on chromosome 18q12. Am J Hum Genet 2002; 71:947-51. [PMID: 12161821 PMCID: PMC378548 DOI: 10.1086/342669] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2002] [Accepted: 06/24/2002] [Indexed: 11/03/2022] Open
Abstract
Smith-McCort dysplasia is a rare autosomal recessive osteochondrodysplasia characterized by short limbs and a short trunk with a barrel-shaped chest. The radiographic phenotype includes platyspondyly, generalized abnormalities of the epiphyses and metaphyses, and a distinctive lacy appearance of the iliac crest. We performed a genomewide scan in a consanguineous family from Guam and found evidence of linkage to loci on chromosome 18q12. Analysis of a second, smaller family was also consistent with linkage to this region, producing a maximum combined two-point LOD score of 3.04 at a recombination fraction of 0 for the marker at locus D18S450. A 10.7-cM region containing the disease gene was defined by recombination events in two affected individuals in the larger family. Furthermore, all affected children in the larger family were homozygous for a subset of marker loci within this region, defining a 1.5-cM interval likely to contain the defective gene. Analysis of three small, unrelated families with Dyggve-Melchior-Clausen syndrome, a radiographically identical disorder with the additional clinical finding of mental retardation, provided evidence of linkage to the same region, a result consistent with the hypothesis that the two disorders are allelic.
Collapse
Affiliation(s)
- Nadia Ehtesham
- Medical Genetics–Birth Defects Center, Ahmanson Department of Pediatrics, Cedars-Sinai Research Institute, Departments of Human Genetics, Medicine, and Pediatrics, University of California–Los Angeles School of Medicine, Los Angeles; University of Texas Health Sciences Center, San Antonio; Children's Hospital Central California, Madera; Department of Pediatrics, University of California–San Francisco School of Medicine, Fresno; Center for Congenital Disorders, Children's Hospital at Montefiore, Albert Einstein College of Medicine, Bronx, New York; and Medical Genetics/Metabolism, Division of Clinical and Metabolic Genetics, Hospital for Sick Children, Toronto
| | - Rita M. Cantor
- Medical Genetics–Birth Defects Center, Ahmanson Department of Pediatrics, Cedars-Sinai Research Institute, Departments of Human Genetics, Medicine, and Pediatrics, University of California–Los Angeles School of Medicine, Los Angeles; University of Texas Health Sciences Center, San Antonio; Children's Hospital Central California, Madera; Department of Pediatrics, University of California–San Francisco School of Medicine, Fresno; Center for Congenital Disorders, Children's Hospital at Montefiore, Albert Einstein College of Medicine, Bronx, New York; and Medical Genetics/Metabolism, Division of Clinical and Metabolic Genetics, Hospital for Sick Children, Toronto
| | - Lily M. King
- Medical Genetics–Birth Defects Center, Ahmanson Department of Pediatrics, Cedars-Sinai Research Institute, Departments of Human Genetics, Medicine, and Pediatrics, University of California–Los Angeles School of Medicine, Los Angeles; University of Texas Health Sciences Center, San Antonio; Children's Hospital Central California, Madera; Department of Pediatrics, University of California–San Francisco School of Medicine, Fresno; Center for Congenital Disorders, Children's Hospital at Montefiore, Albert Einstein College of Medicine, Bronx, New York; and Medical Genetics/Metabolism, Division of Clinical and Metabolic Genetics, Hospital for Sick Children, Toronto
| | - Kent Reinker
- Medical Genetics–Birth Defects Center, Ahmanson Department of Pediatrics, Cedars-Sinai Research Institute, Departments of Human Genetics, Medicine, and Pediatrics, University of California–Los Angeles School of Medicine, Los Angeles; University of Texas Health Sciences Center, San Antonio; Children's Hospital Central California, Madera; Department of Pediatrics, University of California–San Francisco School of Medicine, Fresno; Center for Congenital Disorders, Children's Hospital at Montefiore, Albert Einstein College of Medicine, Bronx, New York; and Medical Genetics/Metabolism, Division of Clinical and Metabolic Genetics, Hospital for Sick Children, Toronto
| | - Berkley R. Powell
- Medical Genetics–Birth Defects Center, Ahmanson Department of Pediatrics, Cedars-Sinai Research Institute, Departments of Human Genetics, Medicine, and Pediatrics, University of California–Los Angeles School of Medicine, Los Angeles; University of Texas Health Sciences Center, San Antonio; Children's Hospital Central California, Madera; Department of Pediatrics, University of California–San Francisco School of Medicine, Fresno; Center for Congenital Disorders, Children's Hospital at Montefiore, Albert Einstein College of Medicine, Bronx, New York; and Medical Genetics/Metabolism, Division of Clinical and Metabolic Genetics, Hospital for Sick Children, Toronto
| | - Alan Shanske
- Medical Genetics–Birth Defects Center, Ahmanson Department of Pediatrics, Cedars-Sinai Research Institute, Departments of Human Genetics, Medicine, and Pediatrics, University of California–Los Angeles School of Medicine, Los Angeles; University of Texas Health Sciences Center, San Antonio; Children's Hospital Central California, Madera; Department of Pediatrics, University of California–San Francisco School of Medicine, Fresno; Center for Congenital Disorders, Children's Hospital at Montefiore, Albert Einstein College of Medicine, Bronx, New York; and Medical Genetics/Metabolism, Division of Clinical and Metabolic Genetics, Hospital for Sick Children, Toronto
| | - Sheila Unger
- Medical Genetics–Birth Defects Center, Ahmanson Department of Pediatrics, Cedars-Sinai Research Institute, Departments of Human Genetics, Medicine, and Pediatrics, University of California–Los Angeles School of Medicine, Los Angeles; University of Texas Health Sciences Center, San Antonio; Children's Hospital Central California, Madera; Department of Pediatrics, University of California–San Francisco School of Medicine, Fresno; Center for Congenital Disorders, Children's Hospital at Montefiore, Albert Einstein College of Medicine, Bronx, New York; and Medical Genetics/Metabolism, Division of Clinical and Metabolic Genetics, Hospital for Sick Children, Toronto
| | - David L. Rimoin
- Medical Genetics–Birth Defects Center, Ahmanson Department of Pediatrics, Cedars-Sinai Research Institute, Departments of Human Genetics, Medicine, and Pediatrics, University of California–Los Angeles School of Medicine, Los Angeles; University of Texas Health Sciences Center, San Antonio; Children's Hospital Central California, Madera; Department of Pediatrics, University of California–San Francisco School of Medicine, Fresno; Center for Congenital Disorders, Children's Hospital at Montefiore, Albert Einstein College of Medicine, Bronx, New York; and Medical Genetics/Metabolism, Division of Clinical and Metabolic Genetics, Hospital for Sick Children, Toronto
| | - Daniel H. Cohn
- Medical Genetics–Birth Defects Center, Ahmanson Department of Pediatrics, Cedars-Sinai Research Institute, Departments of Human Genetics, Medicine, and Pediatrics, University of California–Los Angeles School of Medicine, Los Angeles; University of Texas Health Sciences Center, San Antonio; Children's Hospital Central California, Madera; Department of Pediatrics, University of California–San Francisco School of Medicine, Fresno; Center for Congenital Disorders, Children's Hospital at Montefiore, Albert Einstein College of Medicine, Bronx, New York; and Medical Genetics/Metabolism, Division of Clinical and Metabolic Genetics, Hospital for Sick Children, Toronto
| |
Collapse
|
112
|
Pateder DB, Ferguson CM, Ionescu AM, Schwarz EM, Rosier RN, Puzas JE, O'Keefe RJ. PTHrP expression in chick sternal chondrocytes is regulated by TGF-beta through Smad-mediated signaling. J Cell Physiol 2001; 188:343-51. [PMID: 11473361 DOI: 10.1002/jcp.1118] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
PTHrP regulates the rate of chondrocyte differentiation during endochondral bone formation. The expression of PTHrP and its regulation by TGF-beta, BMP-2, and PTHrP was examined in upper sternal chondrocytes following 1, 3, and 5 days of continuous treatment. While TGF-beta stimulated the expression of PTHrP (5-fold), PTHrP caused a slight inhibition, and BMP-2 markedly inhibited PTHrP mRNA expression. The effect of these factors on PTHrP expression was not simply related to the maturational state of the cells, since BMP-2 increased, while both PTHrP and TGF-beta decreased the expression of type X collagen. TGF-beta isoforms 1, 2, and 3 all stimulated PTHrP expression. Signaling events involved in the induction of PTHrP by TGF-beta were further evaluated in a PTHrP-promoter CAT construct. The effect of TGF-beta, BMP-2, and PTHrP on the PTHrP-promoter paralleled their effects on mRNA expression, with TGF-beta significantly increasing CAT activity, BMP-2 decreasing CAT activity, and PTHrP having a minimal effect. Co-transfection of the TGF-beta signaling molecule, Smad 3, mimicked the effect of TGF-beta (induction of PTHrP promoter), while dominant negative Smad 3 inhibited the induction of the PTHrP promoter by TGF-beta. Furthermore, infection with a Smad 3-expressing retrovirus mimicked the effects of exogenously added TGF-beta, and induced PTHrP mRNA expression in the infected chondrocyte culture. In contrast, a dominant negative Smad 3 completely inhibited PTHrP promoter stimulation by TGF-beta, but only partially blocked the effect of TGF-beta on PTHrP mRNA synthesis. These findings demonstrate that PTHrP is expressed in chondrocytes undergoing endochondral ossification, and show regulation, at least in part, by TGF-beta through Smad mediated signaling events.
Collapse
Affiliation(s)
- D B Pateder
- Center for Musculoskeletal Research, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA
| | | | | | | | | | | | | |
Collapse
|