NCBI Summary:
This gene encodes a sialoglycoprotein that is expressed on mature granulocytes and in many B cells. The encoded protein is anchored via a glycosyl phosphatidylinositol (GPI) link to the cell surface. An alignment of this gene's sequence finds genomic locations with similarity on chromosomes 3p26, 15q21, 15q22, 20q11.2 and Yq11.1. Whether transcription, and corresponding translation, occurs at each of these other genomic locations needs to be experimentally determined.
General function
Cell adhesion molecule
Comment
Cellular localization
Plasma membrane
Comment
Ovarian function
Ovulation, Luteinization
Comment
CD24: a marker of granulosa cell subpopulation and a mediator of ovulation. Dong JP et al. (2019) Granulosa cells (GCs) play a critical role in driving the formation of ovarian follicles and building the cumulus-oocyte complex surrounding the ovum. We are particularly interested in assessing oocyte quality by examining the detailed gene expression profiles of human cumulus single cells. Using single-cell RNAseq techniques, we extensively investigated the single-cell transcriptomes of the cumulus GC populations from two women with normal ovarian function. This allowed us to elucidate the endogenous heterogeneity of GCs by uncovering the hidden GC subpopulation. The subsequent validation results suggest that CD24(+) GCs are essential for triggering ovulation. Treatment with human chorionic gonadotropin (hCG) significantly increases the expression of CD24 in GCs. CD24 in cultured human GCs is associated with hCG-induced upregulation of prostaglandin synthase (ARK1C1, PTGS2, PTGES, and PLA2G4A) and prostaglandin transporter (SLCO2A1 and ABCC4) expression, through supporting the EGFR-ERK1/2 pathway. In addition, it was observed that the fraction of CD24(+) cumulus GCs decreases in PCOS patients compared to that of controls. Altogether, the results support the finding that CD24 is an important mediator of ovulation and that it may also be used for therapeutic target of ovulatory disorders.//////////////////
Identification of new ovulation-related genes in humans by comparing the transcriptome of granulosa cells before and after ovulation triggering in the same controlled ovarian stimulation cycle. Wissing ML 2014 et al.
STUDY QUESTION
Which genes and molecular mechanisms are involved in the human ovulatory cascade and final oocyte maturation?
SUMMARY ANSWER
Up-regulated genes in granulosa cells (GC) represented inflammation, angiogenesis, extracellular matrix, growth factors and genes previously associated with ovarian cancer, while down-regulated genes mainly represented cell cycle and proliferation.
WHAT IS KNOWN ALREADY
Radical changes occur in the follicle during final follicle maturation after the ovulatory trigger: these range from ensuring an optimal milieu for the oocyte in meiotic arrest to the release of a mature oocyte and remodeling into a corpus luteum. A wide range of mediators of final follicle maturation has been identified in rodents, non-human primates and cows.
STUDY DESIGN, SIZE, DURATION
Prospective cohort study including 24 women undergoing ovarian stimulation with the long gonadotrophin-releasing hormone agonist protocol during 2010-2012 at Holbk Fertility Clinic. Nine paired samples of GC and 24 paired samples of follicular fluid (FF) were obtained before and after recombinant human chorionic gonadotrophin (rhCG) administration.
PARTICIPANTS/MATERIALS, SETTING, METHODS
Nine paired (nine arrays before rhCG and nine arrays after rhCG) samples of GC mRNA were amplified and hybridized to Affymetrix Human Gene 1.0 ST GeneChip arrays, compared and bioinformatically analyzed. Eleven selected genes were validated by quantitative reverse transcriptase PCR. FF hormones were analyzed by enzyme-linked immunosorbent assay.
MAIN RESULTS AND THE ROLE OF CHANCE
Eleven hundred and eighty-six genes were differentially expressed (>2-fold, P<0.0001, false discovery rate <0.0012) when comparing GC isolated before and 36 h after hCG, among those were genes known to be expressed at ovulation, i.e. ADAMTS1 and HAS2. Many new ovulation-related genes were revealed, such as CD24, ANKRD22, CLDN11 and FBXO32. FF estrogen, androstenedione and anti-Mllerian hormone decreased significantly while progesterone increased, accompanied by radical changes in the expression of steroidogenic genes (CYP17A, CYP19A, HSD11B1 and HSD11B2, StAR). Genes related to inflammation, angiogenesis, extracellular matrix formation, growth factors and cancer were up-regulated while cell cycle genes were massively down-regulated. Seventy-two genes previously described in connection with ovarian cancer were among the highly regulated genes. In silico analysis for top upstream regulators of the ovulatory trigger suggested-besides LH-TNF, IGF1, PGR, AR, EGR1 (early growth response 1), ERK1/2 (extracellular signal regulated kinase 1/2) and CDKN1A (cyclin-dependent kinase inhibitor 1A) as potential mediators of the LH/hCG response.
LIMITATIONS, REASONS FOR CAUTION
The present dataset was generated from women under hormonal stimulation. However, comparison with a macaque natural cycle whole follicle ovulation dataset revealed major overlap, supporting the idea that the ovulation-related genes found in this study are relevant in the human natural cycle.
WIDER IMPLICATIONS OF THE FINDINGS
These data will serve as a research resource for genes involved in human ovulation and final oocyte maturation. Ovulation-related genes might be good candidate biomarkers of follicle and oocyte health. Further, some of the ovulation-related genes may serve as future ovarian cancer biomarkers.
STUDY FUNDING/COMPETING INTEREST(S)
Grants from the Research Fund of Region Sjlland are gratefully acknowledged. None of the authors declared any conflict of interest.
TRIAL REGISTRATION NUMBER
Not applicable.
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Expression regulated by
LH
Comment
Gene expression increased. Luteinization of porcine preovulatory follicles leads to systematic changes in follicular gene expression. Agca C et al. The LH surge initiates the luteinization of preovulatory follicles and causes hormonal and structural changes that ultimately lead to ovulation and the formation of corpora lutea. The objective of the study was to examine gene expression in ovarian follicles (n = 11) collected from pigs (Sus scrofa domestica) approaching estrus (estrogenic preovulatory follicle; n = 6 follicles from two sows) and in ovarian follicles collected from pigs on the second day of estrus (preovulatory follicles that were luteinized but had not ovulated; n = 5 follicles from two sows). The follicular status within each follicle was confirmed by follicular fluid analyses of estradiol and progesterone ratios. Microarrays were made from expressed sequence tags that were isolated from cDNA libraries of porcine ovary. Gene expression was measured by hybridization of fluorescently labeled cDNA (preovulatory estrogenic or -luteinized) to the microarray. Microarray analyses detected 107 and 43 genes whose expression was decreased or increased (respectively) during the transition from preovulatory estrogenic to -luteinized (P<0.01). Cells within preovulatory estrogenic follicles had a gene-expression profile of proliferative and metabolically active cells that were responding to oxidative stress. Cells within preovulatory luteinized follicles had a gene-expression profile of nonproliferative and migratory cells with angiogenic properties. Approximately, 40% of the discovered genes had unknown function.
Ovarian localization
Granulosa
Comment
Rimon E, et al reported
Gonadotropin-induced gene regulation in human granulosa cells obtained from IVF patients and Modulation of genes coding for growth factors and their receptors and genes involved in cancer and other diseases.
Gonadotropins play a crucial role in ovarian homeostasis and fertilization. However, hypergonadotropin stimulation has been thought to increase the risk for ovarian cancer. Moreover, some correlation between high levels of gonadotropins in the circulation and Alzheimer's disease has been implicated, with no clear evidence on the molecular mechanism involved. Using DNA microarray technology and RNA from gonadotropin-stimulated human granulosa cells, which comprise the main bulk of the ovarian follicular somatic cells, we discovered that stimulation of cells with saturating doses of gonadotropins gives rise to the expression of genes coding for presenilin 1 and 2, along with the up-regulation of genes involved in steroidogenesis such as StAR, cytochrome P450scc enzyme system and aromatase. Moreover, gonadotropin stimulation in these cells dramatically elevates activity of genes coding for epiregulin and amphiregulin, which can bind and activate the EGF receptor and ERB4. These gene products may elevate the risk for ovarian, breast, endometrial and other non-gynecological cancers. Gene transcripts for oncogenes and tumor markers such as pleiomorphic adenoma gene-like 1 (Plagl1) tumor antigen (L6) and claudin 3 were markedly elevated following LH and FSH stimulation. In parallel, downregulation in ovarian cancer 1 (DOC1) and suppression of tumorigenicity (ST5) genes was observed, suggesting a potential increase for cancer development. In contrast, increase in tumor rejection antigen (gp96) 1 and decrease in connective tissue growth factor (CTGF), transforming growth factor-beta 1 induced transcript 1 (TGFB1Il), pim-1 oncogene (PIM1), v-maf musculoaponeurotic fibrosarcoma oncogene homologue (MAF) and CD24 antigen may be associated with a decreased risk for specific cancers. In conclusion, gonadotropin stimulation may modulate specific sets of gene transcripts that may either elevate or reduce the risk for specific diseases.