Proteomic analysis of cervical-vaginal fluid: identification of novel biomarkers for detection of intra-amniotic infection

Abstract

Intra-amniotic infection (IAI) is associated with preterm birth and perinatal mortality. To identify potential biomarkers, we performed a comprehensive survey of the cervical-vaginal fluid (CVF) proteome from a primate IAI model utilizing multidimensional protein identification technology (LC/LC-MS/MS) and MALDI-TOF-MS analyses. Analyses of CVF proteome identified 205 unique proteins and differential expression of 27 proteins in controls and IAI samples. Protein expression signatures and immunodetection of specific biomarkers identified can be employed for noninvasive detection of IAI.

Figure 1

A–B. Functional annotation and cellular localization of proteins expressed in CVF. Two hundred and five proteins identified utilizing MudPIT and gel-based fractionation were analyzed for GeneOntology terms (GO terms) using an annotation database (DAVID, Version 2.0, NIAID). 8 % of the total proteins did not show any known functional annotation.

Figure 2

A–D. Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF-MS) protein profiles of Ureaplasma parvum-induced differential protein levels in non-human primate CVF and AF samples. Profiles demonstrating the 10.8-kDa peak are shown in control samples taken prior to (A) and following (B) experimental IAI. Profiles demonstrating peptides in the 3–5-kDa MW range are shown in C) control samples taken prior to and D) samples taken following experimental IAI. Spectra were processed for baseline subtraction and Savitsky-Golay smoothing, 5 cycles at 10 Da/channel. Spectra representing m/z range from 3000 to 2000 are shown with arrows indicating differentially expressed peaks between control and infection.

Figure 3

Immunodetection of potential CVF biomarkers for IAI. Haptoglobin, unregulated control marker. IGFBP-1 bands represent the intact protein (~30kDa) and proteolytic fragment (~19 kDa).