The roles of TRPV2 in the human ovary and granulosa cell tumors

• Applicants: Dr. Thomas Fröhlich; Privatdozent Dr. Lars Kunz; Professor Dr. Artur Mayerhofer; Professorin Dr. Doris Mayr
• Subject Area: Gynaecology and Obstetrics ; Reproductive Medicine, Urology
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 456828204

Transient receptor potential vanilloid type 2 (TRPV2) is a Ca2+ -permeable cation channel, which is not well-examined regarding expression, activation and function. This is specifically true for human (h)TRPV2, which differs substantially from its rodent counterpart. What activates hTRPV2 in vivo has remained elusive, until a recent report identified reactive oxygen species (ROS), including H2O2, as relevant activators or sensitizers. Production of H2O2 and other ROS was previously identified in the human ovary, in IVF-derived human human granulosa cells (hGCs) and the granulosa cell tumor line KGN, among other by own work. Data mining (human ovary transcriptome data; own proteomic data of hGCs and KGN) and further pilot studies identified TRPV2 in these ovarian cells. Cellular studies indicated that TRPV2 is activated by H2O2 and an agonist. Acutely this leads to influx of Ca2+ and then to the production of cytokines in hGCs, implying a role of this channel in ovarian inflammation. Inflammatory reactions, orchestrated and executed by hGCs, have only recently been described but are of importance in ovulation, the formation and the regression of the corpus luteum. Dysregulation is implicated in polycystic ovarian syndrome (PCOS), a major reason for female infertility. Preliminary results in KGN cells further imply that TRPV2 is linked to cell death of these tumor cells.Thus, TRPV2 could be an important, yet completely unexplored key player in the (human) ovary, which may link ROS actions to – among others - cytokine production or cell death in ovarian follicles and granulosa cell tumors. This project aims to test this hypothesis and further aims to identify yet unknown roles of TRPV2 in the ovary and in human granulosa cell tumors.To this end, expression of TRPV2 in the different follicle stages and in the corpus luteum will be examined in ovaries (human, nonhuman primate (NHP), rodents). We will use cellular models, mainly hGCs, to examine activation and to monitor consequences of activation, employing “omics “approaches (i.e. analyses of gene expression, proteome, secretome). We will employ systemic approaches, including studies in NHP 3D follicle cultures, made possible through international collaboration. We will examine involvement in PCOS using hGCs and a rat model. To explore the role in granulosa cell tumors, expression will be monitored in tissue microarrays and results correlated with clinical data. Studies in additional primary granulosa cell tumors and in KGN will provide mechanistic insights and siRNA-mediated downregulation and CRISPR/Cas9 knockout of TRPV2 will allow to specify and pinpoint the roles of TRPV2. We expect new translational insights into the physiological roles of TRPV2 and its potential to affect ovarian functions and granulosa cell tumors.

• DFG Programme: Research Grants