title: Stem cells, progenitor cells, and lineage decisions in the ovary.
abstract: Exploring stem cells in the mammalian ovary has unleashed a Pandora's box of new insights and questions. Recent evidence supports the existence of stem cells of a number of the different cell types within the ovary. The evidence for a stem cell model producing mural granulosa cells and cumulus cells is strong, despite a limited number of reports. The recent identification of a precursor granulosa cell, the gonadal ridge epithelial-like cell, is exciting and novel. The identification of female germline (oogonial) stem cells is still very new and is currently limited to just a few species. Their origins and physiological roles, if any, are unknown, and their potential to produce oocytes and contribute to follicle formation in vivo lacks robust evidence. The precursor of thecal cells remains elusive, and more compelling data are needed. Similarly, claims of very small embryonic-like cells are also preliminary. Surface epithelial cells originating from gonadal ridge epithelial-like cells and from the mesonephric epithelium at the hilum of the ovary have also been proposed. Another important issue is the role of the stroma in guiding the formation of the ovary, ovigerous cords, follicles, and surface epithelium. Immune cells may also play key roles in developmental patterning, given their critical roles in corpora lutea formation and regression. Thus, while the cellular biology of the ovary is extremely important for its major endocrine and fertility roles, there is much still to be discovered. This review draws together the current evidence and perspectives on this topic.
authors.affiliation: Discipline of Obstetrics and Gynaecology (K.H., D.L.R., S.A.R., R.J.R.), School of Paediatrics and Reproductive Health, Robinson Research Institute, University of Adelaide, Adelaide, South Australia, Australia 5005; Medical Research Council Centre for Reproductive Health (R.A.A.), The University of Edinburgh, The Queens Medical Research Institute, Edinburgh EH16 4TJ, United Kingdom; Department of Anatomy and Developmental Biology (D.W.), Monash University, Clayton, Victoria, Australia 3800; Bio-X Institutes (J.W.), Shanghai Jiao Tong University, Shanghai 200240, China; and Institute of Cell Biology and Centre for Integrative Physiology (E.E.T), The University of Edinburgh, Edinburgh EH8 9XE, United Kingdom.
authors.forename: Katja
authors.initials: K
authors.lastname: Hummitzsch
authors.forename: Richard A
authors.initials: RA
authors.lastname: Anderson
authors.forename: Dagmar
authors.initials: D
authors.lastname: Wilhelm
authors.forename: Ji
authors.initials: J
authors.lastname: Wu
authors.forename: Evelyn E
authors.initials: EE
authors.lastname: Telfer
authors.forename: Darryl L
authors.initials: DL
authors.lastname: Russell
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Robertson
authors.forename: Raymond J
authors.initials: RJ
authors.lastname: Rodgers
mesh_terms: D000818:Animals; D003338:Corpus Luteum / Q000166:cytology; D054885:Cumulus Cells; D004848:Epithelium / Q000196:embryology; D005260:Female; D047109:Fetal Development; D005854:Germ Cells; D006107:Granulosa Cells; D006801:Humans; D006080:Ovarian Follicle / Q000166:cytology / Q000196:embryology / Q000254:growth & development; D010053:Ovary / Q000166:cytology* / Q000196:embryology; D010060:Ovulation; D013234:Stem Cells; D017154:Stromal Cells; D013799:Theca Cells