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Soluble osteopontin inhibits apoptosis of adherent endothelial cells deprived of growth factors *
Author(s) -
Khan S.A.,
LopezChua C.A.,
Zhang J.,
Fisher L.W.,
Sørensen E.S.,
Denhardt D.T.
Publication year - 2002
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.10170
Subject(s) - osteopontin , microbiology and biotechnology , integrin , apoptosis , umbilical vein , cd44 , matricellular protein , chemistry , dna fragmentation , biology , extracellular matrix , programmed cell death , cell , biochemistry , immunology , in vitro
Osteopontin (OPN) is primarily an extracellular glycosylated phosphoprotein capable of stimulating cell migration and cell attachment, predominantly to mineralized surfaces. Found in moderate levels in plasma, it acts as a cytokine able to modify gene expression via integrins and certain CD44 isoforms. In this work we show that soluble OPN inhibits apoptosis of adherent human umbilical vein endothelial cells incubated in medium lacking critical growth factors and cytokines. In a dose‐dependent manner OPN reduced the formation of apoptotic bodies and suppressed DNA fragmentation. OPN also caused an increase in Bcl‐X L mRNA levels, suppressed the apparent dispersion of Bcl‐X L throughout the cytoplasm, and slightly enhanced IκB‐α protein degradation. These data suggest that a function of OPN in homeostatic processes is to facilitate the survival of stressed endothelial cells, possibly by occupying unligated integrins and suppressing integrin‐mediated death. J. Cell. Biochem. 85: 728–736, 2002. © 2002 Wiley‐Liss, Inc.