Homocysteine-induced endoplasmic reticulum stress and growth arrest leads to specific changes in gene expression in human vascular endothelial cells

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.