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Gene expression profiling of early follicular development in primordial, primary, and secondary follicles Yoon SJ, et al .
OBJECTIVE: To study global gene expression profiles of early folliculogenesis in primordial, primary, and secondary follicles. DESIGN: A cDNA microarray study using amplified RNAs from isolated follicles. SETTING: Experimental animal study. ANIMAL(S): Female ICR strain mice (12 days old). INTERVENTION(S): Isolation of follicles at each stage, RNA isolation and amplification, microarray hybridization, and statistical analysis for microarray. MAIN OUTCOME MEASURE(S): Gene lists of various functional groups with an estimated false discovery rate of 5%. Among them, platelet-derived growth factors (PDGFs) and receptors were localized by immunohistochemistry in mouse ovaries. RESULT(S): We analyzed a list of genes according to function, such as apoptosis, cell cycle, cell proliferation and maintenance, cytoskeleton, extracellular matrix, and signal transduction, as well as according to frequency. Among the list of genes, we found all PDGFs (A, B, C, and D) and receptors (alpha and beta) are expressed with differential expression patterns in the oocytes and ovarian cells according to stage of follicular development. CONCLUSION(S): The present report suggests that genome-wide expression profiling using microarray after RNA amplification may become a useful tool to better understand the molecular mechanism(s) involved in early ovarian folliculogenesis.
Cell-Type Localization of Platelet-Derived Growth Factors and Receptors in the Postnatal Rat Ovary and Follicle. Sleer LS et al. Intraovarian growth factors play a significant role in the regulation of follicular selection and growth. In this study, the presence and localization of all members of the family of platelet derived growth factors (PDGF) and receptors (PDGFR) were identified and characterized in the rat ovary and a role in contributing towards growth of preantral follicles was identified. Real-time polymerase chain reaction revealed the presence of mRNA for all platelet derived growth factors (Pdgfa, Pdgfb, Pdgfc and Pdgfd) and receptors (Pdgfra and Pdgfrb) in the rat ovary from birth until four weeks. In situ hybridization and immunohistochemistry were utilized to identify cell-type expression of PDGFs and PDGFRs in rat ovaries from birth until four weeks. Shortly after birth, expression of PDGFRA and PDGFC was observed in and around oocyte clusters, and PDGFRB in stromal cells surrounding oocyte clusters. All members were identified in oocytesof primordial and primary follicles, and in cells of the theca layer of primordial to antral follicles. PDGFRA and PDGFA were also localized to some granulosa cells of secondary and antral follicles in ovaries from rats at days 20 and 24. Thus, localization data suggest both theca-theca and theca-granulosa cell interactions of PDGFs and receptors. Preantral follicles cultured in vitro over five days in serum-free medium plus recombinant PDGFAA, PDGFAB or PDGFBB increased in follicle diameter by 18.32 +/- 2.18%, 17.72 +/- 2.3% and 17.6 +/- 1.81% respectively, representing significantly greater increases than for follicles incubated in serum-free medium alone (11 +/- 1.57%), and suggesting a role for these growth factors in positively influencing early follicle growth.
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