Fibronectin regulates calvarial osteoblast differentiation

Amr Moursi, Caroline H. Damsky, Jonathan Lull, Deborah Zimmerman, Stephen B. Doty, Shin Ichi Aota, Ruth K. Globus

Research output: Contribution to journalArticle

Abstract

The secretion of fibronectin by differentiating osteoblasts and its accumulation at sites of osteogenesis suggest that fibronectin participates in bone formation. To test this directly, we determined whether fibronectin-cell interactions regulate progressive differentiation of cultured fetal rat calvarial osteoblasts. Spatial distributions of α5 integrin subunit, fibronectin, osteopontin (bone sialoprotein I) and osteocalcin (bone Gla-protein) were similar in fetal rat calvaria and mineralized, bone-like nodules formed by cultured osteoblasts. Addition of anti-fibronectin antibodies to cultures at confluence reduced subsequent formation of nodules to less than 10% of control values, showing that fibronectin is required for normal nodule morphogenesis. Anti-fibronectin antibodies selectively inhibited steady-state expression of mRNA for genes associated with osteoblast differentiation; mRNA levels for alkaline phosphatase and osteocalcin were suppressed, whereas fibronectin, type I collagen and osteopontin were unaffected. To identify functionally relevant domains of fibronectin, we treated cells with soluble fibronectin fragments and peptides. Cell-binding fibronectin fragments (type III repeats 6-10) containing the Arg-Gly-Asp (RGD) sequence blocked both nodule initiation and maturation, whether or not they contained a functional synergy site. In contrast, addition of the RGD-containing peptide GRGDSPK alone did not inhibit nodule initiation, although it did block nodule maturation. Thus, in addition to the RGD sequence, other features of the large cell-binding fragments contribute to the full osteogenic effects of fibronectin. Nodule formation and osteoblast differentiation resumed after anti-fibronectin antibodies or GRGDSPK peptides were omitted from the media, showing that the inhibition was reversible and the treatments were not cytotoxic. Outside the central cell-binding domain, peptides from the IIICS region and antibodies to the N terminus did not inhibit nodule formation. We conclude that osteoblasts interact with the central cell-binding domain of endogenously produced fibronectin during early stages of differentiation, and that these interactions regulate both normal morphogenesis and gene expression. .

Original languageEnglish (US)
Pages (from-to)1369-1380
Number of pages12
JournalJournal of Cell Science
Volume109
Issue number6
StatePublished - Jun 1996

Fingerprint

Osteoblasts
Fibronectins
glycyl- arginyl-glycyl-aspartyl-seryl-prolyl-lysine
Osteopontin
Osteocalcin
Anti-Idiotypic Antibodies
Morphogenesis
Osteogenesis
Gene Expression
Messenger RNA
Peptides
Peptide Fragments
Collagen Type I
Skull
Integrins
Cell Communication
Alkaline Phosphatase

Keywords

  • Fetal rat calvarial osteoblast
  • Fibronectin
  • Osteoblast differentiation
  • RGD sequence

ASJC Scopus subject areas

  • Cell Biology

Cite this

Moursi, A., Damsky, C. H., Lull, J., Zimmerman, D., Doty, S. B., Aota, S. I., & Globus, R. K. (1996). Fibronectin regulates calvarial osteoblast differentiation. Journal of Cell Science, 109(6), 1369-1380.

Fibronectin regulates calvarial osteoblast differentiation. / Moursi, Amr; Damsky, Caroline H.; Lull, Jonathan; Zimmerman, Deborah; Doty, Stephen B.; Aota, Shin Ichi; Globus, Ruth K.

In: Journal of Cell Science, Vol. 109, No. 6, 06.1996, p. 1369-1380.

Research output: Contribution to journalArticle

Moursi, A, Damsky, CH, Lull, J, Zimmerman, D, Doty, SB, Aota, SI & Globus, RK 1996, 'Fibronectin regulates calvarial osteoblast differentiation', Journal of Cell Science, vol. 109, no. 6, pp. 1369-1380.
Moursi A, Damsky CH, Lull J, Zimmerman D, Doty SB, Aota SI et al. Fibronectin regulates calvarial osteoblast differentiation. Journal of Cell Science. 1996 Jun;109(6):1369-1380.
Moursi, Amr ; Damsky, Caroline H. ; Lull, Jonathan ; Zimmerman, Deborah ; Doty, Stephen B. ; Aota, Shin Ichi ; Globus, Ruth K. / Fibronectin regulates calvarial osteoblast differentiation. In: Journal of Cell Science. 1996 ; Vol. 109, No. 6. pp. 1369-1380.
@article{9d40752e3b1540fbbfda51f50842313f,
title = "Fibronectin regulates calvarial osteoblast differentiation",
abstract = "The secretion of fibronectin by differentiating osteoblasts and its accumulation at sites of osteogenesis suggest that fibronectin participates in bone formation. To test this directly, we determined whether fibronectin-cell interactions regulate progressive differentiation of cultured fetal rat calvarial osteoblasts. Spatial distributions of α5 integrin subunit, fibronectin, osteopontin (bone sialoprotein I) and osteocalcin (bone Gla-protein) were similar in fetal rat calvaria and mineralized, bone-like nodules formed by cultured osteoblasts. Addition of anti-fibronectin antibodies to cultures at confluence reduced subsequent formation of nodules to less than 10{\%} of control values, showing that fibronectin is required for normal nodule morphogenesis. Anti-fibronectin antibodies selectively inhibited steady-state expression of mRNA for genes associated with osteoblast differentiation; mRNA levels for alkaline phosphatase and osteocalcin were suppressed, whereas fibronectin, type I collagen and osteopontin were unaffected. To identify functionally relevant domains of fibronectin, we treated cells with soluble fibronectin fragments and peptides. Cell-binding fibronectin fragments (type III repeats 6-10) containing the Arg-Gly-Asp (RGD) sequence blocked both nodule initiation and maturation, whether or not they contained a functional synergy site. In contrast, addition of the RGD-containing peptide GRGDSPK alone did not inhibit nodule initiation, although it did block nodule maturation. Thus, in addition to the RGD sequence, other features of the large cell-binding fragments contribute to the full osteogenic effects of fibronectin. Nodule formation and osteoblast differentiation resumed after anti-fibronectin antibodies or GRGDSPK peptides were omitted from the media, showing that the inhibition was reversible and the treatments were not cytotoxic. Outside the central cell-binding domain, peptides from the IIICS region and antibodies to the N terminus did not inhibit nodule formation. We conclude that osteoblasts interact with the central cell-binding domain of endogenously produced fibronectin during early stages of differentiation, and that these interactions regulate both normal morphogenesis and gene expression. .",
keywords = "Fetal rat calvarial osteoblast, Fibronectin, Osteoblast differentiation, RGD sequence",
author = "Amr Moursi and Damsky, {Caroline H.} and Jonathan Lull and Deborah Zimmerman and Doty, {Stephen B.} and Aota, {Shin Ichi} and Globus, {Ruth K.}",
year = "1996",
month = "6",
language = "English (US)",
volume = "109",
pages = "1369--1380",
journal = "Journal of Cell Science",
issn = "0021-9533",
publisher = "Company of Biologists Ltd",
number = "6",

}

TY - JOUR

T1 - Fibronectin regulates calvarial osteoblast differentiation

AU - Moursi, Amr

AU - Damsky, Caroline H.

AU - Lull, Jonathan

AU - Zimmerman, Deborah

AU - Doty, Stephen B.

AU - Aota, Shin Ichi

AU - Globus, Ruth K.

PY - 1996/6

Y1 - 1996/6

N2 - The secretion of fibronectin by differentiating osteoblasts and its accumulation at sites of osteogenesis suggest that fibronectin participates in bone formation. To test this directly, we determined whether fibronectin-cell interactions regulate progressive differentiation of cultured fetal rat calvarial osteoblasts. Spatial distributions of α5 integrin subunit, fibronectin, osteopontin (bone sialoprotein I) and osteocalcin (bone Gla-protein) were similar in fetal rat calvaria and mineralized, bone-like nodules formed by cultured osteoblasts. Addition of anti-fibronectin antibodies to cultures at confluence reduced subsequent formation of nodules to less than 10% of control values, showing that fibronectin is required for normal nodule morphogenesis. Anti-fibronectin antibodies selectively inhibited steady-state expression of mRNA for genes associated with osteoblast differentiation; mRNA levels for alkaline phosphatase and osteocalcin were suppressed, whereas fibronectin, type I collagen and osteopontin were unaffected. To identify functionally relevant domains of fibronectin, we treated cells with soluble fibronectin fragments and peptides. Cell-binding fibronectin fragments (type III repeats 6-10) containing the Arg-Gly-Asp (RGD) sequence blocked both nodule initiation and maturation, whether or not they contained a functional synergy site. In contrast, addition of the RGD-containing peptide GRGDSPK alone did not inhibit nodule initiation, although it did block nodule maturation. Thus, in addition to the RGD sequence, other features of the large cell-binding fragments contribute to the full osteogenic effects of fibronectin. Nodule formation and osteoblast differentiation resumed after anti-fibronectin antibodies or GRGDSPK peptides were omitted from the media, showing that the inhibition was reversible and the treatments were not cytotoxic. Outside the central cell-binding domain, peptides from the IIICS region and antibodies to the N terminus did not inhibit nodule formation. We conclude that osteoblasts interact with the central cell-binding domain of endogenously produced fibronectin during early stages of differentiation, and that these interactions regulate both normal morphogenesis and gene expression. .

AB - The secretion of fibronectin by differentiating osteoblasts and its accumulation at sites of osteogenesis suggest that fibronectin participates in bone formation. To test this directly, we determined whether fibronectin-cell interactions regulate progressive differentiation of cultured fetal rat calvarial osteoblasts. Spatial distributions of α5 integrin subunit, fibronectin, osteopontin (bone sialoprotein I) and osteocalcin (bone Gla-protein) were similar in fetal rat calvaria and mineralized, bone-like nodules formed by cultured osteoblasts. Addition of anti-fibronectin antibodies to cultures at confluence reduced subsequent formation of nodules to less than 10% of control values, showing that fibronectin is required for normal nodule morphogenesis. Anti-fibronectin antibodies selectively inhibited steady-state expression of mRNA for genes associated with osteoblast differentiation; mRNA levels for alkaline phosphatase and osteocalcin were suppressed, whereas fibronectin, type I collagen and osteopontin were unaffected. To identify functionally relevant domains of fibronectin, we treated cells with soluble fibronectin fragments and peptides. Cell-binding fibronectin fragments (type III repeats 6-10) containing the Arg-Gly-Asp (RGD) sequence blocked both nodule initiation and maturation, whether or not they contained a functional synergy site. In contrast, addition of the RGD-containing peptide GRGDSPK alone did not inhibit nodule initiation, although it did block nodule maturation. Thus, in addition to the RGD sequence, other features of the large cell-binding fragments contribute to the full osteogenic effects of fibronectin. Nodule formation and osteoblast differentiation resumed after anti-fibronectin antibodies or GRGDSPK peptides were omitted from the media, showing that the inhibition was reversible and the treatments were not cytotoxic. Outside the central cell-binding domain, peptides from the IIICS region and antibodies to the N terminus did not inhibit nodule formation. We conclude that osteoblasts interact with the central cell-binding domain of endogenously produced fibronectin during early stages of differentiation, and that these interactions regulate both normal morphogenesis and gene expression. .

KW - Fetal rat calvarial osteoblast

KW - Fibronectin

KW - Osteoblast differentiation

KW - RGD sequence

UR - http://www.scopus.com/inward/record.url?scp=0029941250&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0029941250&partnerID=8YFLogxK

M3 - Article

VL - 109

SP - 1369

EP - 1380

JO - Journal of Cell Science

JF - Journal of Cell Science

SN - 0021-9533

IS - 6

ER -