PUBLICATION

Growth plate regulation and osteochondroma formation: insights from tracing proteoglycans in zebrafish models and human cartilage

Authors
de Andrea, C.E., Prins, F.A., Wiweger, M.I., and Hogendoorn, P.C.
ID
ZDB-PUB-110518-25
Date
2011
Source
The Journal of pathology   224(2): 160-168 (Journal)
Registered Authors
Wiweger, Malgorzata
Keywords
growth plate; osteochondroma; proteoglycans; heparan sulphate; gradients; exostosis; zebrafish; bone tumours
MeSH Terms
  • Adolescent
  • Adult
  • Animals
  • Bone Neoplasms/metabolism*
  • Bone Neoplasms/ultrastructure
  • Chondrocytes/metabolism
  • Disease Models, Animal
  • Growth Plate/metabolism*
  • Growth Plate/ultrastructure
  • Humans
  • Microscopy, Electron
  • Microscopy, Phase-Contrast
  • Mutation
  • N-Acetylglucosaminyltransferases/genetics
  • Neoplasm Proteins/metabolism
  • Osteochondroma/metabolism*
  • Osteochondroma/ultrastructure
  • Proteoglycans/deficiency
  • Proteoglycans/metabolism*
  • Zebrafish
PubMed
21506131 Full text @ J. Pathol.
Abstract
Proteoglycans are secreted into the extracellular matrix of virtually all cell types and function in several cellular processes. They consist of a core protein onto which glycosaminoglycans (e.g., heparan or chondroitin sulphates), are attached. Proteoglycans are important modulators of gradient formation and signal transduction. Impaired biosynthesis of heparan sulphate glycosaminoglycans causes osteochondroma, the most common bone tumour to occur during adolescence. Cytochemical staining with positively charged dyes (e.g., polyethyleneimine—PEI) allows, visualisation of proteoglycans and provides a detailed description of how proteoglycans are distributed throughout the cartilage matrix. PEI staining was studied by electron and reflection contrast microscopy in human growth plates, osteochondromas and five different proteoglycan-deficient zebrafish mutants displaying one of the following skeletal phenotypes: dackel (dak/ext2), lacking heparan sulphate and identified as a model for human multiple osteochondromas; hi3073gat3), deficient for most glycosaminoglycans; pinscher (pic/slc35b2), presenting with defective sulphation of glycosaminoglycans; hi954 (uxs1), lacking most glycosaminoglycans; and knypek (kny/gpc4), missing the protein core of the glypican-4 proteoglycan. The panel of genetically well-characterized proteoglycan-deficient zebrafish mutants serves as a convincing and comprehensive study model to investigate proteoglycan distribution and the relation of this distribution to the model mutation status. They also provide insight into the distributions and gradients that can be expected in the human homologue. Human growth plate, wild-type zebrafish and fish mutants with mild proteoglycan defects (hi307 and kny) displayed proteoglycans distributed in a gradient throughout the matrix. Although the mutants pic and hi954, which had severely impaired proteoglycan biosynthesis, showed no PEI staining, dak mutants demonstrated reduced PEI staining and no gradient formation. Most chondrocytes from human osteochondromas showed normal PEI staining. However, approximately 10% of tumour chondrocytes were similar to those found in the dak mutant (e.g., lack of PEI gradients). The cells in the reduced PEI-stained areas are likely associated with loss-of-function mutations in the EXT genes, and they might contribute to tumour initiation by disrupting the gradients.

Genes / Markers
Figures
Show all Figures
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping