Proteomic strategies uncover novel aging and age-related disease signatures in the human post-menopausal ovary

Reproductive decline begins when women are in their mid-thirties, increasing the risk for infertility, miscarriages, and ovarian cancer. This is characterized by molecular changes within the ovarian microenvironment, including fibrosis, accumulation of collagen, and loss of hyaluronan. Cellular senescence is a pro-inflammatory stress response that results in the production of a Senescence-Associated Secretory Phenotype (SASP). The presence of senescent cells is consistent with the fibro-inflammation signature in the aging ovary, thus giving rise to the importance of studying senescence in this tissue.

Here, the postmenopausal ovary was studied to identify 1) the ovarian SASP in an induced model of senescence and 2) to understand age-associated changes that may contribute to the increased incidence of high-grade serous ovarian cancer (HGSOC) in non-Hispanic Black women, which disproportionally affects this population.Explant cultures of cortex and medulla regions from one donor were treated with doxorubicin (doxo) exposure to induce senescence or DMSO as control. Conditioned media from human explants were collected and processed by label-free quantitative proteomics strategies. Upon senescence induction by doxorubicin, 135 and 184 SASP factors were significantly-altered in cortex and medulla explants, respectively. Upregulated biological processes in both the cortex and medulla explants are related to chromatin remodeling and assembly. Significantly-altered proteins in both cortex and medulla explants include Serpin H1, Tenascin, and Periostin, which are well established SASP factors. To understand ovarian aging in the context of ovarian cancer risk, human ovarian cortex and medulla tissues (N=42) were acquired prospectively from six non-Hispanic black (NHB) and five non-Hispanic white (NHW) non-ovarian cancer post-menopausal patients. Ovarian tissue was prepared for analyses by having native and decellularized conditions and samples were prepared using label free-quantitative proteomics strategies. In this analysis, 4,257 quantifiable protein groups with ≥2 unique peptides were detected in the native cortex (NHB/NHW). Significantly-altered proteins include SASP factors Serpin H1, Tenascin, and Periostin. Upregulated biological processes are related to metabolism whereas downregulated processes are related to coagulation, ECM organization, and wound healing. Several significantly-altered SASP proteins in decellularized cortex are also present in the native condition, thus confirming the preservation of the extracellular matrix. Up- and downregulated biological processes in the decellularized are consistent with the native condition.

These analyses provide great insight into the ovarian SASP and how the SASP may contribute to the higher incidence of HGSOC in non-Hispanic Black women. With this information, the mechanisms that underlie ovarian aging will be better understood and potential therapeutics may be developed to improve health outcomes.