Oral Presentation ESA-SRB 2023 in conjunction with ENSA

Characterization of the role for Dynamin 2 in the regulation of human endometrial receptivity (#145)

Wei Zhou 1 2 , Poppy Downing 1 2 , Michaela Sacco 1 2 , Leiani L Santos 1 2 , Wan T Teh 1 3 4 5 , Evdokia Dimitriadis 1 2
  1. Department of Obstetrics, Gynaecology and Newborn Health, University of Melbourne, Melbourne, VIC, Australia
  2. Gynaecology Research Centre, Royal Women's Hospital, Melbourne, VIC, Australia
  3. The Royal Women’s Hospital, Parkville, VIC, Australia, Melbourne, Victoria, Australia
  4. Melbourne IVF, Melbourne, Victoria
  5. Epworth HealthCare, Melbourne, Victoria, Australia

Abnormal endometrial receptivity is a major cause of infertility and implantation failure. In each menstrual cycle, the endometrium remodels to accept an implanting blastocyst only in the window of ‘receptivity’. During this window, the endometrial luminal epithelium becomes adhesive to an implanting blastocyst. Endometrial glands produce and secrete factors apically into the uterine cavity to prepare the initial blastocyst attachment and implantation. However, we have a profound lack of knowledge on how these processes are regulated. The dynamin (DNM) family comprises three canonical isoforms of GTPase generally responsible for the regulation of membrane trafficking events such as exocytosis and intracellular trafficking. This study aimed to characterise the role of DNM in regulating endometrial receptivity. Our qPCR data showed that among three isoforms examined, only DNM2 was significantly upregulated (P<0.05) in the fertile receptive endometrium compared to the non-receptive, proliferative endometrium. Further characterization of DNM2 confirmed a significant increase (P<0.05) of immunostaining intensity in the fertile receptive endometrium, compared to proliferative endometrium. In fertile receptive endometrium, DNM2 was localized in the apical and basal surfaces of the glandular and luminal epithelium, respectively. Endometrial organoids were further used to mimic endometrial glands in vitro since DNM2 showed a conserved apical membrane localization. DNM2 expression in fertile endometrium-derived organoids was significantly increased (P<0.05) by progesterone stimulation, compared to estrogen treatment only, as confirmed by qPCR and immunoblotting. Such an increase was not recorded in infertile endometrium-derived organoids. Using Ishikawa cells (receptive endometrial cell line) to mimic endometrial luminal epithelium in vitro, it was identified that knockdown of DNM2 significantly reduced (P<0.01) Ishikawa cell adhesive capacity to trophoblast progenitor spheroids (blastocyst surrogates). Furthermore, DNM2 knockdown in Ishikawa cells significantly affected the expression of receptivity markers including SPP1 and STAT3. Collectively the data encourages further investigation of the mechanisms underpinning DNM2 regulation on endometrial receptivity.