Cellular patterns of insulin-like growth factor system gene expression in murine chondrogenesis and osteogenesis.

Journal Article (Journal Article)

In situ hybridization histochemistry was used to map cellular patterns of gene expression for the insulin-like growth factor (IGF) system in developing murine skeleton from embryonic day 15 (E15) through postnatal day 25 (P25). IGF-I receptor and IGF-II receptor messenger RNAs (mRNAs) are both selectively concentrated in developing chondrocytes and osteoblasts. IGF-II and IGF-binding protein-5 and -6(IGFBP-5 and -6) mRNAs are abundant in mesenchymal condensations and chondroblasts on E15. Chondrocyte IGF-II mRNA levels remain high, but IGFBP-5 and -6 mRNAs decline significantly as cartilage matures. Low levels of IGFBP-6 mRNA are detected in postnatal chondrocytes up to at least P25, but IGFBP-5 mRNA is no longer detected in chondrocytes after E18. IGF-I and IGFBP-2, -3, and -4 mRNAs are detected in surrounding mesenchymal tissue, but are not detected in mesenchymal condensations or chondrocytes at any stage of development. IGFBP-3 mRNA is localized in sprouting capillaries invading the perichondrium and periosteum throughout development. IGF-I, IGF-II, and IGFBP-2, -4, -5, and -6 mRNAs are detected in osteoblasts localized in zones of endochondral ossification from E18 to at least P25. IGFBP-1 mRNA is not detected in cartilage or bone cells at any stage of development. These data confirm the recent report by Shinar et al. that IGF-II, but not IGF-I, mRNA is detected in rat chondrocytes in vivo and show that this pattern also applies to the mouse. The present study demonstrates, for the first time, the cell-specific patterns of IGF-I and -II receptor and IGFBP-2 to -6 gene expression during the processes of chondro- and osteogenesis in vivo. Interestingly, IGF-II, both IGF receptors, and IGFBP-5 and -6 are simultaneously coexpressed in chondrocyte precursors early in skeletal development, suggesting functional interactions between these specific factors in chondrogenesis. Both IGFs, both IGF receptors, and IGFBP-2, -4, -5, and -6 are all expressed in osteoblasts, providing evidence for potential local interactions between these IGF system components in osteogenesis. Thus, 9 of 10 known components of the IGF system demonstrate dynamic cell-specific patterns of gene expression during chondro- and osteogenesis, supporting the view that the IGF system has a complex and integral role within the developing skeleton.

Full Text

Duke Authors

Cited Authors

  • Wang, E; Wang, J; Chin, E; Zhou, J; Bondy, CA

Published Date

  • June 1995

Published In

Volume / Issue

  • 136 / 6

Start / End Page

  • 2741 - 2751

PubMed ID

  • 7750499

International Standard Serial Number (ISSN)

  • 0013-7227

Digital Object Identifier (DOI)

  • 10.1210/endo.136.6.7750499

Language

  • eng

Conference Location

  • United States