Immediate cell signal by bone-related peptides in human osteoclast-like cells

R. Paniccia, S. Colucci, M. Grano, M. Serra, A. Z. Zallone, A. Teti

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Abstract

We tested whether recognition of bone-related peptides regulates intracellular Ca2+ concentration ([Ca2+](i)) of giant cells, with osteoclast-like characteristics, from a human giant cell tumor of bone (GCT). [Ca2+](i) was measured in single cells by fura 2 fluorometry. GCT cells were sensitive to bone sialoprotein-II (BSP-II), osteopontin (OPN), and related fragments. Responses consisted of a prompt increase of [Ca2+](i), mostly transient, with a peak followed by a rapid return toward baseline. Responses were not mimicked by bovine plasma fibronectin. Sensitivity of GCT cells to bone peptides was specific, since BALB/3T3 fibroblasts and U-937 histiocytic lymphoma cells with monocytic phenotype failed to respond to BSP- II and OPN fragments. GRGDSP synthetic esapeptide, carrying the Arg-Gly-Asp adhesive motif, and GRGESP (Asp replaced by Glu), but not the GRADSP (Gly replaced by Ala), were active in inducing [Ca2+](i) transients as well. Responses were observed also in cells treated with the BSP-II 1C fragment, lacking any known adhesive sequence, indicating that the active peptides inducing [Ca2+](i) increments may be multiple. Sensitivity to extracellular matrix peptides was present in a variable fraction of the cells and was downregulated on long-term culture. The mechanism inducing [Ca2+](i) elevations was mostly related to Ca2+ release from thapsigargin-sensitive intracellular pools.

Original languageEnglish
JournalAmerican Journal of Physiology - Cell Physiology
Volume265
Issue number5 34-5
Publication statusPublished - 1993

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Keywords

  • Arg-Gly-Asp
  • Arg-Gly-Glu
  • bone protein
  • bone sialoprotein- II
  • extracellular matrix
  • intracellular calcium concentration
  • osteopontin

ASJC Scopus subject areas

  • Cell Biology
  • Clinical Biochemistry
  • Physiology

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