Combining Bioinformatics and Experiments to Identify CREB1 as a Key Regulator in Senescent Granulosa Cells

Abstract

Aging of functional ovaries occurs many years before aging of other organs in the female body. In recent years, a greater number of women continue to postpone their pregnancies to later stages in their lives, raising concerns of the effect of ovarian aging. Mitochondria play an important role in the connection between the aging granulosa cells and oocytes. However, the underlying mechanisms of mitochondrial dysfunction in these cells remain poorly understood. Therefore, we evaluated the molecular mechanism of the aging granulosa cells, including aspects such as accumulation of mitochondrial reactive oxygen species, reduction of mtDNA, imbalance of mitochondrial dynamics, and diminished cell proliferation. Here, we applied bioinformatics approaches, and integrated publicly available resources, to investigate the role of CREB1 gene expression in reproduction. Senescence hallmark enrichment and pathway analysis suggested that the downregulation of bioenergetic-related genes in CREB1. Gene expression analyses showed alterations in genes related to energy metabolism and ROS production in ovary tissue. We also demonstrate that the biogenesis of aging granulosa cells is subject to CREB1 binding to the PRKAA1 and PRKAA2 upstream promoters. In addition, cofactors that regulate biogenesis significantly increase the levels of SIRT1 and PPARGC1A mRNA in the aging granulosa cells. These findings demonstrate that CREB1 elevates an oxidative stress-induced senescence in granulosa cells by reducing the mitochondrial function.

The Molecular Regulation in the Pathophysiology in Ovarian Aging

“…Aging increases mitochondrial DNA (mtDNA) instability, which causes the accumulation of mtDNA mutations in cells within the ovaries, especially in oocytes. Mitochondria play an essential role in ovarian follicle development and early embryonic development, and a decline in ovarian function also severely affects mitochondrial biogenesis and function in oocytes and peripheral granulosa cells [24]. Therefore, mitochondrial dysfunction in oocytes, which possess the highest mtDNA copy number among all cells, accelerates ovarian insufficiency, resulting in pregnancy failure.…”

“…One study observed that the aneuploidy rate in oocytes of aged mice was 31.6%, whereas the rate in young mice was 4.9% [49]. Telomere shortening commonly exists in aged oocytes mainly due to an aginginduced increase in the ROS content of the cells [24,50] and has been shown to contribute to the DNA damage response [51]. The quality of granulosa cells in the periphery of oocytes also affects oocyte quality.…”

“…The quality of granulosa cells in the periphery of oocytes also affects oocyte quality. With increasing age, cumulus and granulosa cells also experience an increase in DNA damage and telomere shortening [24,[52][53][54]. Multi-omics studies have shown that aging may cause significant changes in genes within oocytes involved in cell-cycle signal transduction and changes in the expression of proteins related to SAC, DNA stability, chromatid separation, cell division, microtubules, and regulatory RNAs [55][56][57].…”

Identification of Novel Biomarkers and Candidate Drug in Ovarian Cancer

“…With a high degree of malignancy and a short survival period, ovarian cancer is often detected at an advanced stage, and the current treatment is still based on surgery and chemotherapy [ 20 ]. Current studies have shown that the abnormal expression of several genes may be closely associated with the survival of ovarian cancer patients through the screening of gene expression profiles, and that these genes are involved in the development and progression of ovarian cancer by promoting or suppressing apoptosis, generating or reversing chemotherapy resistance [ 21 , 22 ]. In this study, we used bioinformatics analysis, ovarian cancer tissue microarray, and multiple types of ovarian cancer cell lines to screen out mRNAs that may be related to the prognosis of ovarian cancer patients and provide a basis for future clinical practice and scientific research.…”

Qualitative and Quantitative Ovarian and Peripheral Blood Mitochondrial DNA (mtDNA) Alterations: Mechanisms and Implications for Female Fertility

“…The total cellular and mitochondrial ROS of the H 2 O 2 -treated group was higher when compared to that of the control group. Authors also observed a significant reduction in the mtDNA copy number in senescent cells characterized by a lack of mitochondrial sufficiency [ 39 ].…”