Project description:Primordial follicle assembly is the process by which ovarian primordial follicles are formed. During follicle assembly oocyte nests break down and a layer of pre-granulosa cells surrounds individual oocytes to form primordial follicles. The pool of primordial follicles formed is the source of oocytes for ovulation during a femaleM-bM-^@M-^Ys reproductive life. Complex networks of cellular signaling and gene expression are essential for any biological process. A systems biology experimental approach provides a global view of these gene relationships in a particular developmental process. The current study utilized a systems approach to detect all genes that are differentially expressed in response to seven different growth factor and hormone treatments known to influence primordial follicle assembly in a neonatal rat ovary culture system. One novel growth factor, basic fibroblast growth factor (FGF2), was experimentally determined to inhibit follicle assembly. The different growth factor and hormone treatments were all found to affect the same physiological pathways, but each treatment affected a unique set of differentially expressed genes (signature gene set). A gene bionetwork analysis identified gene modules of coordinately expressed interconnected genes and it was found that different gene modules appear to accomplish distinct tasks during primordial follicle assembly. Unique gene networks were identified for a number of the modules and signature gene sets. Predictions of physiological pathways important to follicle assembly were validated using ovary culture experiments in which ERK1/2 (MAPK1) activity was increased. A number of the highly interconnected genes in these gene networks have previously been linked to primary ovarian insufficiency (POI) and polycystic ovarian disease syndrome (PCOS). Observations have identified novel factors and gene networks that regulate primordial follicle assembly. This systems approach has helped elucidate the molecular control of primordial follicle assembly and provided potential therapeutic targets for the treatment of ovarian disease. We used microarrays to determine genes expressed differentially between control and P0 ovaries treated with 7 growth factors: AMH, CTGF, estradiol (E2), Activin-a, FGF2, progesterone (P4), and TNFa. RNA samples from 7 control samples are compared to 3 growth factor treated ovary samples for each AMH (human Anti-MM-CM-<lerian hormone), CTGF (connective tissue growth factor ), estradiol (E2), TNF (tumor necrosis factor ), FGF2 (fibroblast growth factor 2), Inhba (inhibin, beta A), and 2 samples for progesterone (P4).

Project description:The oocytes found within the primordial follicles of mammalian ovaries remain quiescent for months to years until they receive the appropriate signals to undergo the primordial to primary follicle transition and initiate folliculogenesis. The molecular mechanisms and extracellular signaling factors that regulate this process remain to be fully elucidated. The current study investigates the mechanisms utilized by anti-Müllerian hormone (AMH; i.e. Müllerian inhibitory substance) to inhibit the primordial to primary follicle transition. Ovaries from 4-day-old rats were placed into organ culture and incubated in the absence or presence of AMH, either alone or in combination with known stimulators of follicle transition, including basic fibroblast growth factor (bFGF), kit ligand (KITL), or keratinocyte growth factor (KGF). Following 10 days of culture, the ovaries were sectioned, stained, and morphologically evaluated to determine the percentage of primordial versus developing follicles. As previously demonstrated, AMH treatment decreased primordial to primary follicle transition. Interestingly, AMH inhibited the stimulatory actions of KITL, bFGF, and KGF. Therefore, AMH can inhibit the basal and stimulated development of primordial follicles. To investigate the mechanism of AMH actions, the influence AMH has on the ovarian transcriptome was analyzed. AMH treatment when compared with controls was found to alter the expression of 707 genes. The overall effect of AMH exposure is to decrease the expression of stimulatory factors, increase the expression of inhibitory factors, and regulate cellular pathways (e.g. transforming growth factor beta signaling pathway) that result in the inhibition of primordial follicle development. Analysis of the regulatory factors and cellular pathways altered by AMH provides a better understanding of the molecular control of primordial follicle development. Keywords: expression analysis, follicle assembly, AMH effect, ovary

Project description:Primordial follicle assembly is a process that occurs in the embryonic or early post natal ovary in which oocyte nests break down to form individual primordial follicles. The size of this initial pool of primordial follicles in part determines the reproductive lifespan of the female. Connective tissue growth factor (CTGF) was identified as a potential regulatory candidate for this process in a previous microarray analysis of follicle development. The current study examines the effects of CTGF and associated transforming growth factor beta 1 (TGFbeta-1) on follicle assembly. Ovaries were removed from newborn rat pups and placed in an organ culture system for two days to measure the effect of these factors on follicle assembly. In addition, ovaries were cultured and treated for ten days to determine the potential of CTGF and TGFbeta-1 to manipulate the primordial follicle pool size over a longer developmental time period. The ovaries treated with CTGF for two days were found to have an increased proportion of assembled follicles. TGFbeta-1 had no effect on primordial follicle assembly and in combination with CTGF decreased oocyte number in the ovary after two days of culture. Over ten days of treatment only the combined treatment of CTGF and TGFbeta-1 was found to cause an increase in the proportion of assembled follicles. Interestingly, treatment with TGFbeta-1 alone resulted in fewer total oocytes in the ovary and decreased the primordial follicle pool size after ten days of culture. Observations indicate that CTGF alone or in combination with TGFbeta-1 stimulates primordial follicle assembly and TGFbeta-1 can decrease the primordial follicle pool size. CTGF was found to regulate the ovarian transcriptome during primordial follicle assembly and an integrative network of genes was identified. CTGF is one of the first growth factors shown to promote primordial follicle assembly, while TGFbeta-1 is one of the first factors shown to decrease the primordial follicle pool size. These observations suggest the possibility of manipulating primordial follicle pool size and influencing female reproductive lifespan. We used microarrays to determine genes expressed differentially between control and CTGF (connective tissue growth factor) treated P0 ovary RNA samples from 3 control groups are compared to 3 CTGF treated ovary groups

Project description:Primordial follicle assembly is the process by which ovarian primordial follicles are formed. During follicle assembly oocyte nests break down and a layer of pre-granulosa cells surrounds individual oocytes to form primordial follicles. The pool of primordial follicles formed is the source of oocytes for ovulation during a female’s reproductive life. Complex networks of cellular signaling and gene expression are essential for any biological process. A systems biology experimental approach provides a global view of these gene relationships in a particular developmental process. The current study utilized a systems approach to detect all genes that are differentially expressed in response to seven different growth factor and hormone treatments known to influence primordial follicle assembly in a neonatal rat ovary culture system. One novel growth factor, basic fibroblast growth factor (FGF2), was experimentally determined to inhibit follicle assembly. The different growth factor and hormone treatments were all found to affect the same physiological pathways, but each treatment affected a unique set of differentially expressed genes (signature gene set). A gene bionetwork analysis identified gene modules of coordinately expressed interconnected genes and it was found that different gene modules appear to accomplish distinct tasks during primordial follicle assembly. Unique gene networks were identified for a number of the modules and signature gene sets. Predictions of physiological pathways important to follicle assembly were validated using ovary culture experiments in which ERK1/2 (MAPK1) activity was increased. A number of the highly interconnected genes in these gene networks have previously been linked to primary ovarian insufficiency (POI) and polycystic ovarian disease syndrome (PCOS). Observations have identified novel factors and gene networks that regulate primordial follicle assembly. This systems approach has helped elucidate the molecular control of primordial follicle assembly and provided potential therapeutic targets for the treatment of ovarian disease. We used microarrays to determine genes expressed differentially between control and P0 ovaries treated with 7 growth factors: AMH, CTGF, estradiol (E2), Activin-a, FGF2, progesterone (P4), and TNFa.

Project description:Primordial follicle assembly is a process that occurs in the embryonic or early post natal ovary in which oocyte nests break down to form individual primordial follicles. The size of this initial pool of primordial follicles in part determines the reproductive lifespan of the female. Connective tissue growth factor (CTGF) was identified as a potential regulatory candidate for this process in a previous microarray analysis of follicle development. The current study examines the effects of CTGF and associated transforming growth factor beta 1 (TGFbeta-1) on follicle assembly. Ovaries were removed from newborn rat pups and placed in an organ culture system for two days to measure the effect of these factors on follicle assembly. In addition, ovaries were cultured and treated for ten days to determine the potential of CTGF and TGFbeta-1 to manipulate the primordial follicle pool size over a longer developmental time period. The ovaries treated with CTGF for two days were found to have an increased proportion of assembled follicles. TGFbeta-1 had no effect on primordial follicle assembly and in combination with CTGF decreased oocyte number in the ovary after two days of culture. Over ten days of treatment only the combined treatment of CTGF and TGFbeta-1 was found to cause an increase in the proportion of assembled follicles. Interestingly, treatment with TGFbeta-1 alone resulted in fewer total oocytes in the ovary and decreased the primordial follicle pool size after ten days of culture. Observations indicate that CTGF alone or in combination with TGFbeta-1 stimulates primordial follicle assembly and TGFbeta-1 can decrease the primordial follicle pool size. CTGF was found to regulate the ovarian transcriptome during primordial follicle assembly and an integrative network of genes was identified. CTGF is one of the first growth factors shown to promote primordial follicle assembly, while TGFbeta-1 is one of the first factors shown to decrease the primordial follicle pool size. These observations suggest the possibility of manipulating primordial follicle pool size and influencing female reproductive lifespan. We used microarrays to determine genes expressed differentially between control and CTGF (connective tissue growth factor) treated P0 ovary

Project description:The oocytes found within the primordial follicles of mammalian ovaries remain quiescent for months to years until they receive the appropriate signals to undergo the primordial to primary follicle transition and initiate folliculogenesis. The molecular mechanisms and extracellular signaling factors that regulate this process remain to be fully elucidated. The current study investigates the mechanisms utilized by anti-MÃ¼llerian hormone (AMH; i.e. MÃ¼llerian inhibitory substance) to inhibit the primordial to primary follicle transition. Ovaries from 4-day-old rats were placed into organ culture and incubated in the absence or presence of AMH, either alone or in combination with known stimulators of follicle transition, including basic fibroblast growth factor (bFGF), kit ligand (KITL), or keratinocyte growth factor (KGF). Following 10 days of culture, the ovaries were sectioned, stained, and morphologically evaluated to determine the percentage of primordial versus developing follicles. As previously demonstrated, AMH treatment decreased primordial to primary follicle transition. Interestingly, AMH inhibited the stimulatory actions of KITL, bFGF, and KGF. Therefore, AMH can inhibit the basal and stimulated development of primordial follicles. To investigate the mechanism of AMH actions, the influence AMH has on the ovarian transcriptome was analyzed. AMH treatment when compared with controls was found to alter the expression of 707 genes. The overall effect of AMH exposure is to decrease the expression of stimulatory factors, increase the expression of inhibitory factors, and regulate cellular pathways (e.g. transforming growth factor beta signaling pathway) that result in the inhibition of primordial follicle development. Analysis of the regulatory factors and cellular pathways altered by AMH provides a better understanding of the molecular control of primordial follicle development. Experiment Overall Design: RNA samples from two control groups (pooled untreated cultured ovaries) are compared to two treated groups (pooled cultured ovaries treated with AMH)

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Inhibitory Actions of Anti-Müllerian Hormone (AMH) on Ovarian Primordial Follicle Assembly

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