Proteome analysis reveals elevated serum levels of clusterin in patients with preeclampsia

Abstract

Preeclampsia is a pregnancy-specific syndrome and a major cause of maternal mortality. The pathophysiology of preeclampsia is unknown, and no proteome analysis of preeclampsia has been reported. We sought to identify proteins associated with preeclampsia using a proteomic technique and performed two-dimensional electrophoresis (2-DE) on sera from six patients with preeclampsia and six normal pregnant women, followed by comparison of the SYPRO Ruby-stained 2-DE profiles. A group of overexpressed spots was identified in the limited study set. Overexpressed spots were identified as clusterin by 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. Additionally, sera of 80 preeclamptic women and 80 normal pregnant women were processed by immunoassay methods to confirm changes in clusterin concentrations quantitatively. Immunoassays showed that clusterin levels in the 80 preeclamptic women were significantly higher than those in the 80 controls (mean +/- SD; 1.62 +/- 0.46 times reference level in preeclamptic women vs. 1.30 +/- 0.46 times reference level in controls, P < 0.001). Proteomic analysis of serum proteins is a promising tool for studying preeclampsia pathophysiology and identifying proteins associated with preeclampsia.

Recent advances in blood‐related proteomics

“…As shown in Table 2, haptoglobin has been shown to be a potential marker of cancer [37][38][39]. Watanabe et al [40], after having analyzed serum samples from pregnant women by 2-DE, were able to identify in women presenting with preeclampsia a group of overexpressed spots corresponding to clusterin. In a large series, they confirmed that the levels of clusterin were significantly higher in pregnant women with preeclampsia than without [40].…”

“…Watanabe et al [40], after having analyzed serum samples from pregnant women by 2-DE, were able to identify in women presenting with preeclampsia a group of overexpressed spots corresponding to clusterin. In a large series, they confirmed that the levels of clusterin were significantly higher in pregnant women with preeclampsia than without [40]. Also using 2-DE and MS analyses, Kwak et al [41] showed that the serum proteome of patients with acute myeloid leukemia differed from that of controls.…”

An altered pattern of circulating apolipoprotein E3 isoforms is implicated in preeclampsia

“…A 2DE study of HELLP syndrome, a severe form of preeclampsia, identified one downregulated and five upregulated plasma proteins (7). In another study, serum clusterin was reportedly increased in preeclampsia with fetal growth restriction (6). Although these studies indicated the potential of proteomic approaches, only small numbers of women with severe disease were included.…”

“…Recently, two-dimensional gel electrophoresis (2DE) proteomic techniques have been used to investigate changes in the plasma proteome in preeclampsia (6,7). A 2DE study of HELLP syndrome, a severe form of preeclampsia, identified one downregulated and five upregulated plasma proteins (7).…”

Preeclamptic toxemia: a disease ripe for proteomic discovery

“…The use of 2DE gel ana lysis has also been applied to plasma samples in preeclampsia [24]. Plasma samples from six women with preeclampsia and six matched normotensive controls were analyzed with clusterin identified as being overexpressed in the preeclampsia samples.…”