Polypeptides Synthesized and Released by Rat Ectopic Uterine Implants Differ from those of the Uterus in Culture1

Abstract

Unique endometriosis-specific secretory proteins would be of paramount importance as noninvasive markers for diagnosis and evaluation of therapeutic approaches for endometriosis. Furthermore, identification of endometriosis-specific secretory proteins may be an important step towards understanding the pathophysiology of endometriosis-associated pain and infertility. Therefore this study was designed to assess protein synthesis and secretion by ectopic uterine implants from steroid-treated and reproductively cyclic rats with surgically induced endometriosis. Uteri, ectopic uterine implants, and control tissues were incubated in L-[35S]methionine or D-[6-3H]glucosamine for 0-24 h and 24-48 h. De novo-synthesized proteins released into the culture media were identified using two-dimensional SDS-PAGE, fluorography, and computer-assisted image analysis. Two distinct groups of ectopic uterine implant proteins were identified: ENDO I (M(r) 40,000-50,000; pI 4.0-5.2) and ENDO II (M(r) 28,000-32,000; pI 7.5-9.0) were produced by ectopic uterine implants and not the uteri. A third group of proteins, previously identified in culture media of the uteri from progesterone-treated rats and called PUP-1 (M(r) 70,000; pI 5.7), was synthesized and secreted by ectopic uterine implants 24-48 h later than in parallel uterine cultures. The detection of ectopic uterine implant proteins suggests biochemical characteristics of the ectopic tissue that may be used to develop unique markers for endometriosis. Furthermore, the delayed synthesis and secretion of the uterine protein PUP-1 by the ectopic uterine implants illustrates yet another example of the asynchronous behavior of these two tissues, which may be related to the etiology or pathophysiology of the disease.

Molecular profiling of experimental endometriosis identified gene expression patterns in common with human disease

“…The rat ectopic and eutopic endometrium have the same differential secretory pattern of protein synthesis and are histologically similar to what has been observed in human endometriosis. Furthermore, rats with surgically induced endometriosis exhibit a decrease in their fecundity and NK cell activity that parallels the human disease (8)(9)(10)(11). Moreover, we have recently shown that, similar to the human disease, this animal model is characterized by a dysregulation of the TNF system systemically and at the peritoneal level (12).…”

Proteasomes and Proteasome Activator 200 kDa (PA200) Accumulate on Chromatin in Response to Ionizing Radiation

“…For experiments 2 and 3, endometriosis was surgically induced in rats (Endo) as previously described by Vernon and Wilson [13] and routinely performed in our laboratory [19,21,33,34,37,38]. A unilateral ovariohysterectomy was performed, and sections of the removed uterus were autotransplanted into the arterial cascade of the small intestine.…”

“…TIMP1 represents at least 10% to 15% of proteins secreted into the peritoneal cavity by both rat implants and human endometriotic lesions [33,35]. Because products from endometriotic lesions in the peritoneal fluid (PF) bathe the ovary and enter the uterus through the oviducts, endometriotic TIMP1 may influence the entire reproductive system, including ovulation, oocyte quality, embryo development, and early spontaneous pregnancy loss [17].…”

“Spot”-ting differences between the ectopic and eutopic endometrium of endometriosis patients

“…Few endometriosis-specific proteins, secreted in vitro by endometriotic tissue in a rat model, have been identified using the proteomics approach (25,26). Protein profiles of eutopic endometrium (EUE) of women with and without endometriosis have also been compared (27,28).…”