Post-Translational Modifications and Protein-Specific Isoforms in Endometriosis Revealed by 2D DIGE

Abstract

Endometriosis is a chronic disorder affecting approximately 10% of women in whom endometrial tissue forms painful lesions outside the uterus. It has a major impact on their physical, mental and social well-being but has no known cure, and there is no nonsurgical means of diagnosis. We have used a proteomic approach to identify proteins with altered abundance in the eutopic endometrium of endometriosis patients in the midsecretory phase of the menstrual cycle. 2D-differential in gel electrophoresis (DIGE) and mass spectrometry identified 20 proteins that were present at different levels in endometriosis patients (p < 0.05), many of which have not previously been associated with endometriosis. Protein abundance changes did not correlate well with published gene array data, emphasizing the extensive post-translational modification that occurs in this tissue. Abundance or localization changes in endometrial tissue were validated by immunohistochemistry and Western blotting for three proteins, vimentin (VIM), peroxiredoxin 6 (PRDX6), and ribonuclease/angiogenin inhibitor 1 (RNH1), while observed changes could not be confirmed for coronin 1A (CORO1A) or transgelin (TAGLN2). In addition, multiple charge and size isoforms were observed for PDRX6 and vimentin (VIM), and an additional PDRX6 isoform was observed in endometriosis patients that was below the level of detection in healthy women. Biological pathway analysis identified that cytoskeletal remodeling via keratin intermediate filaments, processing of the cystic fibrosis transmembrane receptor (CFTR), the glucocorticoid receptor subunit alpha (GCR), and heat shock factor 1 (HSF1) were all significantly over-represented features in endometriosis patients. This study highlights the highly dynamic nature of endometrial tissue and suggests that considerable post-translational modification of proteins is a key factor in the pathology of endometriosis.

Nestin upregulation characterizes vascular remodeling secondary to hypertension in the rat

“…1A). Previous studies have detected the existence of multiple isoforms of vimentin, and phosphorylation of the intermediate filament protein has also been reported (20,28,34). It remains unknown if the lower molecular weight band detected in the present study represented an isoform or a dephosphorylated state of vimentin.…”

Ovine corpus luteum proteins, with functions including oxidative stress and lipid metabolism, show complex alterations during implantation

“…We selected 2DE for the proteomic analysis because it is a powerful and flexible technique for investigation of protein expression in multiple sample groups (Stephens et al 2010). Equal amounts of protein from each ewe, in each group, were combined to make five protein pools as follows: cyclic ewes on days 12 (C12) and 16 (C16) and pregnant ewes on days 12 (P12), 16 (P16), and 20 (P20).…”

Proteomic analysis of the sheep caruncular and intercaruncular endometrium reveals changes in functional proteins crucial for the establishment of pregnancy

“…To test our hypothesis, endometrium was collected from cycling ewes on days 12 (C12) and 16 (C16) of the oestrous cycle and from pregnant ewes at conceptus pre-attachment (P12), implantation (P16) and early post-implantation (P20). Two-dimensional gel electrophoresis (2DE)-based proteomics (Fowler et al 2007, Stephens et al 2010, Arianmanesh et al 2011) was employed to characterise peri-implantation-specific alterations in the endometrial proteome in order to enhance our understanding of the molecular endometrium environment supporting early conceptus development and survival.…”