Pa. Outinen et al., Homocysteine-induced endoplasmic reticulum stress and growth arrest leads to specific changes in gene expression in human vascular endothelial cells, BLOOD, 94(3), 1999, pp. 959-967
Alterations in the cellular redox potential by homocysteine promote endothe
lial cell (EC) dysfunction, an early event in the progression of atherothro
mbotic disease. In this study, we demonstrate that homocysteine causes endo
plasmic reticulum (ER) stress and growth arrest in human umbilical vein end
othelial cells (HUVEC). To determine if these effects reflect specific chan
ges in gene expression, cDNA microarrays were screened using radiolabeled c
DNA probes generated from mRNA derived from HUVEC, cultured in the absence
or presence of homocysteine. Good correlation was observed between expressi
on profiles determined by this method and by Northern blotting. Consistent
with its adverse effects on the ER, homocysteine alters the expression of g
enes sensitive to ER stress (ie, GADD45, GADD153, ATF-4. YY1). Several othe
r genes observed to be differentially expressed by homocysteine are known t
o mediate cell growth and differentiation (ie, GADD45, GADD153, Id-1, cycli
n D1, FRA-2), a finding that supports the observation that homocysteine cau
ses a dose-dependent decrease in DNA synthesis in HUVEC. Additional gene pr
ofiles also show that homocysteine decreases cellular antioxidant potential
(glutathione peroxidase, NKEF-B PAG, superoxide dismutase, clusterin), whi
ch could potentially enhance the cytotoxic effects of agents or conditions
known to cause oxidative damage. These results successfully demonstrate the
use of cDNA microarrays in identifying homocysteine-respondent genes and i
ndicate that homocysteine-induced ER stress and growth arrest reflect speci
fic changes in gene expression in human vascular EC. (C) 1999 by The Americ
an Society of Hematology.