Molecular and cellular studies on eutopic and ectopic endometrium

Endometriosis is defined as the growth of endometrium-like tissue outside the uterine cavity and causes pelvic pain and infertility. In this thesis, I have used multiple techniques to investigate potential endometriosis-linked genes and biomarkers and the potential use of an animal model for endometriosis research. Endometriosis is a complex heritable genetic disease. FOXP1 (Forkhead box protein P1) was initially selected for analysis as it was identified as a potential endometriosis-linked gene by our collaborators at the Queensland Institute of Medical Research (QIMR). My study has shown that FOXP1 proteins are expressed in human endometrium through the menstrual cycle and in endometriotic ectopic lesions, but lost in endometrial adenocarcinoma. Further genome-wide association studies at QIMR showed that FOXP1 was not associated with endometriosis; however, my study suggests that FOXP1 may have functions in endometriosis. The activation of cancer-associated fibroblasts is crucial for the onset and progression of tumour growth. As endometriosis is recognised as a cancer-like disease, I hypothesised that key markers of fibroblast activation would be highly expressed in endometriotic lesions relative to eutopic endometrium. Using laser capture microdissection (LCM) in conjunction with CD10 immunostaining, I have shown that mRNA expression of key markers in fibroblast activation was similar between eutopic and ectopic endometrial stroma in endometriotic lesions from women with endometriosis. However, the mRNA expression of TGFβ1, SMAD3 and SMAD4 were at a higher level in glandular epithelial cells from eutopic compared to ectopic endometrium. My data suggests that biological functions mediated through TGFβ and SMADs in epithelial cells may play an important role in endometriosis. An animal xenograft model has been developed to examine the effects of long-term progestin (MPA) treatment on vascular remodelling in the human endometrium. In this model, I have shown that the blood vessels present in the CD10-positive endometrial component of the xenograft were dominated by vessels of human origin. In addition, vessel proliferation and maturation were decreased after 4-weeks treatment with MPA compared to estradiol-17β only. In combination, these results show that the vascular changes seen in the CD10-positive endometrial component of the xenograft mimic the clinical features observed in women using long-term progestin therapies. Using the animal xenograft model developed in the previous study, I have shown that there were no significant changes in vessel size, the number of vessel profiles, mural cell proliferation or vessel maturation between xenografts exposed to short-term and long-term progesterone treatment. My data also indicates that endometrial tissues from premenopausal women are more suitable for xenograft studies than these from postmenopausal women. This PhD has made a significant contribution to endometriosis research. It has highlighted the importance of endometriosis research in disease diagnosis and management. Experimental approaches used in this thesis provide powerful tools for endometriosis research. Future studies using these experimental approaches, combined with genetic research, will broaden our understanding of the disease with the ultimate aims of early diagnosis, symptom relief, cure and prevention.