Details

Autor(en) / Beteiligte

• Zimolo, Z
• Wesolowski, G
• Tanaka, H
• Hyman, J L
• Hoyer, J R
• Rodan, G A

Titel

Soluble alpha sub(v) beta sub(3)-integrin ligands raise [Ca super(2+)] sub(i) in rat osteoclasts and mouse-derived osteoclast-like cells

Ist Teil von

• American journal of physiology: endocrinology and metabolism, 1994-01, Vol.266 (2), p.C376-C381

Erscheinungsjahr

1994

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• We evaluated the possible involvement of intracellular Ca super(2+) concentration ([Ca super(2+)] sub(i)) changes in the action of alpha sub(v) beta sub(3)-ligands, known to regulate osteoclast function. Rat osteoclasts or mouse osteoclast-like cells, as examined by microfluorimetry and fura 2, showed a transient [Ca super(2+)] sub(i) increase when perfused with (all 0.1 mu M) vitronectin, osteopontin, polypeptide echistatin, fibronectin, and Arg-Gly-Asp-Asp and Arg-Gly-Asp-Ser peptides (10 super(-4) M) but not with laminin, collagen I, collagen IV, or [Ala super(24)]echistatin, in which Ala was substituted for Arg in the Arg-Gly-Asp complex. The threshold for echistatin was 10 pM, the 50% effective concentration was 1 nM, and the median [Ca super(2+)] sub(i) increase was 420 nM above the resting level (217 plus or minus 22 nM) at saturating concentration of 0.1 mu M. Echistatin did not cause Mn super(2+) influx, and 10 mu M nifedipine, 10 nM omega -conotoxin, 5 mM Ni super(2+), or Cd super(2+) did not prevent [Ca super(2+)] sub(i) change. However, extracellular Ca super(2+) was needed for the [Ca super(2+)] sub(i) increase, probably enabling ligand-integrin interaction. Polyclonal and monoclonal (LM609) antibody as well as depletion of [Ca super(2+)] sub(i) stores with 5 mu M thapsigargin and Ca super(2+)-free medium abolished the [Ca super(2+)] sub(i) increase, after restoring extracellular Ca super(2+). Furthermore, the LM609 antibody induced a Ca super(2+) signal in the presence or absence of extracellular Ca super(2+), suggesting that the alpha sub(v) beta sub(3)-ligand interaction is mediated at least partially by Ca super(2+) mobilized from intracellular stores.