Comprehensive Proteomic Analysis of Human Endometrial Fluid Aspirate

Abstract

The endometrial fluid is a noninvasive sample which contains numerous secreted proteins representative of endometrial function and reflects the state of the endometrium. In this study, we describe, for the first time, a comprehensive catalogue of proteins of the endometrial fluid during the secretory phase of the menstrual cycle. To achieve this objective, three different but complementary strategies were used: First, in-solution digestion followed by reverse phase high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS); second, protein separation by denaturing one-dimensional electrophoresis (SDS-PAGE) followed by HPLC-MS/MS analysis. Finally, twodimensional polyacrylamide gel electrophoresis (2D-PAGE) followed by MALDI-TOF/TOF analysis. The combination of the three strategies led to the successful identification of 803 different proteins in the International Protein Index (IPI) human database (v3.48). An extensive description of the endometrial fluid proteome will help provide the basis for a better understanding of a number of diseases and processes, including endometriosis, endometrial cancer and embryo implantation. We believe that the thorough catalogue of proteins presented here can serve as a valuable reference for the study of embryo implantation and for future biomarker discovery involved in pathologic alterations of endometrial function.

Proteomes of the Female Genital Tract During the Oestrous Cycle

“…The expression of the transcriptome of the endometrium along the oestrous cycle was investigated in bovine (20), equine (21) and mouse (22). In human, the proteome of the uterus along the menstrual cycle was studied either on endometrium epithelium (23)(24)(25)(26) or on uterine fluid (27)(28)(29). However, the variation of the proteome of the uterine fluid during the oestrous cycle is not known.…”

Proteomic Analysis of Menstrual Blood

“…When all three body fluids are compared menstrual blood contained a total of 385 proteins (36% of total) not found in vaginal fluid or venous blood (supplemental Table S4). In addition to venous blood and vaginal fluid, the 1061 menstrual blood proteins identified here were also compared with 722 proteins identified by Casado-Vela et al (22) in endometrial fluid aspirate, and 95 human proteins identified by DeSouza et al (3) in proliferative and secretory endometrial tissue. Although 167 proteins were shared between the endometrial fluid and menstrual blood proteomes, 151 of these were also common to venous blood and/or vaginal fluid, leaving only 16 common to menstrual blood alone.…”

Proteomics and the search for biomarkers of female reproductive diseases

“…Until recently, little was known of the composition of the endometrial secretome. Three recent studies (Casado-Vela et al 2009, Hannan et al 2009a, Scotchie et al 2009) have begun to address this issue. Casado-Vela et al (2009) applied three complementary proteomics strategies to analyse uterine aspirates from women in the secretory phase: HPLC tandem MS (MS/MS), denaturing one-dimensional gel electrophoresis followed by HPLC/MS/MS and 2DE followed by MALDI-TOF MS.…”

“…In total, 803 different proteins were identified in aspirates; of these, several of the 22 most abundant were serum proteins. Among the known endometrial secreted proteins found in the aspirate were IL18, MMP9, mucins-1 and -16, vitamin D-binding protein and glycodelin (Casado-Vela et al 2009). However, changes with the menstrual cycle phase or in infertile women were not examined.…”