Growth factor receptor-protein bound 2 (GRB2) upregulation in the placenta in preeclampsia implies a possible role for ras signalling

Objectives: To screen for genes with altered expression in placentas from pregnancies complicated by preeclampsia. Study design: To corroborate gene expression profile of preeclamptic and normal placentas (ATLAS™ Clontech), by dot blot, Northern blot analysis and RT-PCR for growth factor receptor bound-protein 2 (GRB2), using immunohistochemistry to localize its expression in the placenta. Results: Increased expression of GRB2 upregulated in the microarrays was found in preeclampsia by Dot blot and Northern blot analysis. RT-PCR performed with primers specific for GRB2 and its alternatively spliced isoform GRB3-3 showed that most of the cDNA represented in the array was GRB2. The protein was localized to the smooth muscle wall of stem vessels by immunohistochemistry. Conclusion: The ras signalling activated by placental receptor tyrosine kinases may play a role in the segmental thickening of the stem vascular wall in preeclamptic placentas, resulting in reduced blood flow to the developing fetus.