Limits...
Matrix metalloproteinase 9 and vascular endothelial growth factor are essential for osteoclast recruitment into developing long bones.

Engsig MT, Chen QJ, Vu TH, Pedersen AC, Therkidsen B, Lund LR, Henriksen K, Lenhard T, Foged NT, Werb Z, Delaissé JM - J. Cell Biol. (2000)

Bottom Line: Hanahan. 2000.Cell Biol. 2:737-744).These observations identify specific actions of MMP-9 and VEGF that are critical for early bone development.

View Article: PubMed Central - PubMed

Affiliation: OSTEOPRO A/S and Center for Clinical and Basic Research, DK-2750 Herlev/Ballerup, Denmark. me@osteopro.dk

ABSTRACT
Bone development requires the recruitment of osteoclast precursors from surrounding mesenchyme, thereby allowing the key events of bone growth such as marrow cavity formation, capillary invasion, and matrix remodeling. We demonstrate that mice deficient in gelatinase B/matrix metalloproteinase (MMP)-9 exhibit a delay in osteoclast recruitment. Histological analysis and specialized invasion and bone resorption models show that MMP-9 is specifically required for the invasion of osteoclasts and endothelial cells into the discontinuously mineralized hypertrophic cartilage that fills the core of the diaphysis. However, MMPs other than MMP-9 are required for the passage of the cells through unmineralized type I collagen of the nascent bone collar, and play a role in resorption of mineralized matrix. MMP-9 stimulates the solubilization of unmineralized cartilage by MMP-13, a collagenase highly expressed in hypertrophic cartilage before osteoclast invasion. Hypertrophic cartilage also expresses vascular endothelial growth factor (VEGF), which binds to extracellular matrix and is made bioavailable by MMP-9 (Bergers, G., R. Brekken, G. McMahon, T.H. Vu, T. Itoh, K. Tamaki, K. Tanzawa, P. Thorpe, S. Itohara, Z. Werb, and D. Hanahan. 2000. Nat. Cell Biol. 2:737-744). We show that VEGF is a chemoattractant for osteoclasts. Moreover, invasion of osteoclasts into the hypertrophic cartilage requires VEGF because it is inhibited by blocking VEGF function. These observations identify specific actions of MMP-9 and VEGF that are critical for early bone development.

Show MeSH

Related in: MedlinePlus

In situ hybridization and immunostaining of MMP-9 in sections of diaphysis of developing metatarsals. Two sets of adjacent sections of E17 metatarsals were prepared (A, B and C, D). In each set, one section was hybridized with antisense MMP-9 probe (A), or immunostained for MMP-9 (C); their respective adjacent sections were stained both for CD34 immunoreactivity and TRAP activity (B and D). Strong hybridization signals (A) and MMP-9 immunoreactivity (C) are seen outside the calcified cartilage (cc) (arrows). Signals for TRAP activity (red) in the adjacent sections (B and D) (arrows) correspond to the localizations of the MMP-9 hybridization (A) and immunoreactivity (C) signals, respectively. CD34 signals (brown) (B and D) are abundant in the periosteal cell layer (po) and do not have clearly matching MMP-9 hybridization (A) or immunoreactivity signals (C). Bars, 50 μm.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2169432&req=5

Figure 4: In situ hybridization and immunostaining of MMP-9 in sections of diaphysis of developing metatarsals. Two sets of adjacent sections of E17 metatarsals were prepared (A, B and C, D). In each set, one section was hybridized with antisense MMP-9 probe (A), or immunostained for MMP-9 (C); their respective adjacent sections were stained both for CD34 immunoreactivity and TRAP activity (B and D). Strong hybridization signals (A) and MMP-9 immunoreactivity (C) are seen outside the calcified cartilage (cc) (arrows). Signals for TRAP activity (red) in the adjacent sections (B and D) (arrows) correspond to the localizations of the MMP-9 hybridization (A) and immunoreactivity (C) signals, respectively. CD34 signals (brown) (B and D) are abundant in the periosteal cell layer (po) and do not have clearly matching MMP-9 hybridization (A) or immunoreactivity signals (C). Bars, 50 μm.

Mentions: We then localized MMP-9 mRNA and protein in these metatarsals, and compared their localization to (pre)osteoclasts and endothelial cells, the cell types showing invasive activity. We identified these cells by staining them for TRAP and CD34, respectively. We prepared sets of adjacent sections stained for TRAP/CD34, and MMP-9 mRNA or MMP-9 immunoreactivity (Fig. 4). We detected MMP-9 at E17, the developmental stage at which the osteoclast precursors become TRAP+ (Scheven et al. 1986). The analysis of the adjacent sections showed that the strong MMP-9 mRNA and protein signals were restricted to TRAP+ cells, and did not correspond to endothelial cells. Therefore, the major source of MMP-9 in primitive metatarsals that are about to undergo invasion at E17 is the (pre)osteoclasts. These observations show that there is a close spatial-temporal correlation between MMP-9 and invasion of the osteoclasts into the core of the developing bones.


Matrix metalloproteinase 9 and vascular endothelial growth factor are essential for osteoclast recruitment into developing long bones.

Engsig MT, Chen QJ, Vu TH, Pedersen AC, Therkidsen B, Lund LR, Henriksen K, Lenhard T, Foged NT, Werb Z, Delaissé JM - J. Cell Biol. (2000)

In situ hybridization and immunostaining of MMP-9 in sections of diaphysis of developing metatarsals. Two sets of adjacent sections of E17 metatarsals were prepared (A, B and C, D). In each set, one section was hybridized with antisense MMP-9 probe (A), or immunostained for MMP-9 (C); their respective adjacent sections were stained both for CD34 immunoreactivity and TRAP activity (B and D). Strong hybridization signals (A) and MMP-9 immunoreactivity (C) are seen outside the calcified cartilage (cc) (arrows). Signals for TRAP activity (red) in the adjacent sections (B and D) (arrows) correspond to the localizations of the MMP-9 hybridization (A) and immunoreactivity (C) signals, respectively. CD34 signals (brown) (B and D) are abundant in the periosteal cell layer (po) and do not have clearly matching MMP-9 hybridization (A) or immunoreactivity signals (C). Bars, 50 μm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2169432&req=5

Figure 4: In situ hybridization and immunostaining of MMP-9 in sections of diaphysis of developing metatarsals. Two sets of adjacent sections of E17 metatarsals were prepared (A, B and C, D). In each set, one section was hybridized with antisense MMP-9 probe (A), or immunostained for MMP-9 (C); their respective adjacent sections were stained both for CD34 immunoreactivity and TRAP activity (B and D). Strong hybridization signals (A) and MMP-9 immunoreactivity (C) are seen outside the calcified cartilage (cc) (arrows). Signals for TRAP activity (red) in the adjacent sections (B and D) (arrows) correspond to the localizations of the MMP-9 hybridization (A) and immunoreactivity (C) signals, respectively. CD34 signals (brown) (B and D) are abundant in the periosteal cell layer (po) and do not have clearly matching MMP-9 hybridization (A) or immunoreactivity signals (C). Bars, 50 μm.
Mentions: We then localized MMP-9 mRNA and protein in these metatarsals, and compared their localization to (pre)osteoclasts and endothelial cells, the cell types showing invasive activity. We identified these cells by staining them for TRAP and CD34, respectively. We prepared sets of adjacent sections stained for TRAP/CD34, and MMP-9 mRNA or MMP-9 immunoreactivity (Fig. 4). We detected MMP-9 at E17, the developmental stage at which the osteoclast precursors become TRAP+ (Scheven et al. 1986). The analysis of the adjacent sections showed that the strong MMP-9 mRNA and protein signals were restricted to TRAP+ cells, and did not correspond to endothelial cells. Therefore, the major source of MMP-9 in primitive metatarsals that are about to undergo invasion at E17 is the (pre)osteoclasts. These observations show that there is a close spatial-temporal correlation between MMP-9 and invasion of the osteoclasts into the core of the developing bones.

Bottom Line: Hanahan. 2000.Cell Biol. 2:737-744).These observations identify specific actions of MMP-9 and VEGF that are critical for early bone development.

View Article: PubMed Central - PubMed

Affiliation: OSTEOPRO A/S and Center for Clinical and Basic Research, DK-2750 Herlev/Ballerup, Denmark. me@osteopro.dk

ABSTRACT
Bone development requires the recruitment of osteoclast precursors from surrounding mesenchyme, thereby allowing the key events of bone growth such as marrow cavity formation, capillary invasion, and matrix remodeling. We demonstrate that mice deficient in gelatinase B/matrix metalloproteinase (MMP)-9 exhibit a delay in osteoclast recruitment. Histological analysis and specialized invasion and bone resorption models show that MMP-9 is specifically required for the invasion of osteoclasts and endothelial cells into the discontinuously mineralized hypertrophic cartilage that fills the core of the diaphysis. However, MMPs other than MMP-9 are required for the passage of the cells through unmineralized type I collagen of the nascent bone collar, and play a role in resorption of mineralized matrix. MMP-9 stimulates the solubilization of unmineralized cartilage by MMP-13, a collagenase highly expressed in hypertrophic cartilage before osteoclast invasion. Hypertrophic cartilage also expresses vascular endothelial growth factor (VEGF), which binds to extracellular matrix and is made bioavailable by MMP-9 (Bergers, G., R. Brekken, G. McMahon, T.H. Vu, T. Itoh, K. Tamaki, K. Tanzawa, P. Thorpe, S. Itohara, Z. Werb, and D. Hanahan. 2000. Nat. Cell Biol. 2:737-744). We show that VEGF is a chemoattractant for osteoclasts. Moreover, invasion of osteoclasts into the hypertrophic cartilage requires VEGF because it is inhibited by blocking VEGF function. These observations identify specific actions of MMP-9 and VEGF that are critical for early bone development.

Show MeSH
Related in: MedlinePlus