Proteomic analysis reveals an elevated expression of heat shock protein 27 in preeclamptic placentas.

Aim: The purpose of this study was to identify the placental proteins that are associated with preeclampsia by performing proteomic analysis.

Methods: To identify the proteins associated with preeclampsia, we performed two-dimensional electrophoresis (2-DE), followed by silver staining. The overexpressed proteins were identified by performing matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS), followed by peptide mass fingerprinting, a protein database search and Western blot analysis. Immunohistochemical staining was performed to determine the localization of the overexpressed Hsp27.

Results: By use of 2-DE and MALDI-TOF-MS analysis, twelve differentially expressed proteins were identified, of which four proteins were upregulated and eight proteins were downregulated. One of the upregulated spots was identified as Hsp27. Immunohistochemical analysis showed that Hsp27 was mainly located in the trophoblasts. The Western blot analysis showed that the expression of Hsp27 in the tissues of the preeclampsia placenta was significantly increased.

Conclusions: Our study confirmed that four proteins are upregulated and eight proteins are downregulated in preeclampsia. These differentially expressed proteins include signal transduction protein and molecular chaperon protein, in which Hsp27 is upregulated. We suggest that the increased expression level of Hsp27 might be correlated with the pathophysiology of preeclampsia.