Eosinophil chemotactic factor-L (ECF-L) enhances osteoclast formation by increasing ICAM-1 expression

Veronica Garcia Palacios, Ho Yeon Chung, Sun Jin Choi, Noriyoshi Kurihara, Jun Won Lee, Lori A. Ehrlich, Robert Collins, G. David Roodman

Research output: Contribution to journalArticle

2 Scopus citations


Eosinophil chemotactic factor-L (ECF-L) is a novel stimulator of osteoclast (OCL) formation that acts at the differentiation/fusion stage of OCL formation, and is a cofactor for RANK ligand (RANKL). We examined the effects of ECF-L on the intracellular signaling pathways utilized by RANKL, and on the expression of ICAM-1/LFA-1 to determine its mechanism of action. RAW 264.7 and bone marrow cells were treated with RANKL and/or ECF-L Fc protein to determine their effect on NF-κB and AP-1 activity. ECF-L by itself only modestly increased NF-κB binding and JNK activity in RAW 264.7 cells, which were further enhanced by RANKL. In contrast, ECF-L Fc increased LFA-1α and ICAM-1 mRNA levels 1.8-fold in mouse marrow cultures, and anti-ICAM-1 almost completely inhibited OCL formation induced by 10-10 M 1,25-(OH) 2D3, and ECF-L Fc. Furthermore, ECF-L Fc did not enhance OCL formation by ICAM-1 knockout (KO) cells. Increased expression of ICAM-1 by ECF-L appears to be critical for its effects on OCL formation.

Original languageEnglish (US)
Pages (from-to)240-243
Number of pages4
JournalAnnals of the New York Academy of Sciences
Issue number1
StatePublished - Apr 2006
Externally publishedYes


  • ECF-L
  • ICAM-1
  • Osteoclasts

ASJC Scopus subject areas

  • Neuroscience(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • History and Philosophy of Science

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