Project description:Women are born with millions of primordial follicles which gradually decrease with increasing age and this irreversible supply of follicles completely exhausts at menopause. The fertility capacity of women diminishes in parallel with aging. The mechanisms for reproductive aging are not fully understood. In our recent work we observed a decline in BRCA1 mediated DNA repair in aging rat primordial follicles. To further understand the age-related molecular changes, we performed microarray gene expression analysis using total RNA extracted from immature (18â20 days) and aged (400â450 days) rat primordial follicles. The results of current microarray study revealed that there were 1011 (>1.5 fold, p<0.05) genes differentially expressed between two groups in which 422 genes were up-regulated and 589 genes were down-regulated in aged rat primordial follicles compared to immature. The gene ontology and pathway analysis of differentially expressed genes revealed a critical biological function such as cell cycle, oocyte meiosis, chromosomal stability, transcriptional activity, DNA replication and DNA repair were affected by age and this considerable difference in gene expression profiles may have adverse influence on oocyte quality. Our data provide information on the processes that may contribute to aging and age-related decline in fertility. In total of 6 samples, 3 replicate samples were from immature rat primordial follicles and 3 replicate samples were from aged rat primordial follicles. For each replicate sample, the primordial follicles isolated from multiple isolations (each time 10-20 rat ovaries) were finally pooled in order to get required quantity of RNA.
Project description:Women are born with millions of primordial follicles which gradually decrease with increasing age and this irreversible supply of follicles completely exhausts at menopause. The fertility capacity of women diminishes in parallel with aging. The mechanisms for reproductive aging are not fully understood. In our recent work we observed a decline in BRCA1 mediated DNA repair in aging rat primordial follicles. To further understand the age-related molecular changes, we performed microarray gene expression analysis using total RNA extracted from immature (18–20 days) and aged (400–450 days) rat primordial follicles. The results of current microarray study revealed that there were 1011 (>1.5 fold, p<0.05) genes differentially expressed between two groups in which 422 genes were up-regulated and 589 genes were down-regulated in aged rat primordial follicles compared to immature. The gene ontology and pathway analysis of differentially expressed genes revealed a critical biological function such as cell cycle, oocyte meiosis, chromosomal stability, transcriptional activity, DNA replication and DNA repair were affected by age and this considerable difference in gene expression profiles may have adverse influence on oocyte quality. Our data provide information on the processes that may contribute to aging and age-related decline in fertility.
Project description:The assembly of the developmentally arrested primordial follicle and subsequent transition to the primary follicle are poorly understood processes critical to ovarian biology. Abnormal primordial follicle development can lead to pathologies such as premature ovarian failure. The current study used a genome-wide expression profile to investigate primordial follicle assembly and development. Rat ovaries with predominantly unassembled, primordial, or primary follicles were obtained. RNA from these ovaries was hybridized to rat microarray gene chips, and the gene expression (i.e., ovarian transcriptome) was compared between the developmental stages. Analysis of the ovarian transcriptome demonstrated 148 genes up-regulated and 50 genes down-regulated between the unassembled and primordial follicle stages. Observations demonstrate 80 genes up-regulated and 44 genes down-regulated between the primordial and primary follicle stages. The analysis demonstrated 2332 genes common among the three developmental stages, 146 genes specific for the unassembled follicles, 94 genes specific for the primordial follicles, and 151 genes specific for the primary follicles. Steroidogenic genes are up-regulated between unassembled and primordial follicles, and then many are again down-regulated between primordial and primary follicles. The hormones inhibin and Mullerian inhibitory substance (MIS) display a similar pattern of expression with the highest levels of mRNA in the primordial follicles. Several novel unknown genes that had dramatic changes in expression during primordial follicle development were also identified. Gene families/clusters identified that were up-regulated from unassembled to primordial follicles include growth factors and signal transduction gene clusters, whereas a down-regulated gene family was the synaptonemal complex genes associated with meiosis. Gene families/clusters that were up-regulated between primordial and primary follicles included immune response genes, metabolic enzymes, and proteases, whereas down-regulated gene families include the globulin genes and some steroidogenic genes. The expression of several growth factors changed during primordial follicle development, including vascular endothelial growth factor and insulin-like growth factor II. Elucidation of how these changes in gene expression coordinate primordial follicle assembly and the primordial to primary follicle transition provides a better understanding of these critical biological processes and allows selection of candidate regulatory factors for further investigation. Experiment Overall Design: RNA samples from two control groups (pooled untreated cultured ovaries) are compared to two treated groups (pooled cultured ovaries treated with progesterone)
Project description:The assembly of the developmentally arrested primordial follicle and subsequent transition to the primary follicle are poorly understood processes critical to ovarian biology. Abnormal primordial follicle development can lead to pathologies such as premature ovarian failure. The current study used a genome-wide expression profile to investigate primordial follicle assembly and development. Rat ovaries with predominantly unassembled, primordial, or primary follicles were obtained. RNA from these ovaries was hybridized to rat microarray gene chips, and the gene expression (i.e., ovarian transcriptome) was compared between the developmental stages. Analysis of the ovarian transcriptome demonstrated 148 genes up-regulated and 50 genes down-regulated between the unassembled and primordial follicle stages. Observations demonstrate 80 genes up-regulated and 44 genes down-regulated between the primordial and primary follicle stages. The analysis demonstrated 2332 genes common among the three developmental stages, 146 genes specific for the unassembled follicles, 94 genes specific for the primordial follicles, and 151 genes specific for the primary follicles. Steroidogenic genes are up-regulated between unassembled and primordial follicles, and then many are again down-regulated between primordial and primary follicles. The hormones inhibin and Mullerian inhibitory substance (MIS) display a similar pattern of expression with the highest levels of mRNA in the primordial follicles. Several novel unknown genes that had dramatic changes in expression during primordial follicle development were also identified. Gene families/clusters identified that were up-regulated from unassembled to primordial follicles include growth factors and signal transduction gene clusters, whereas a down-regulated gene family was the synaptonemal complex genes associated with meiosis. Gene families/clusters that were up-regulated between primordial and primary follicles included immune response genes, metabolic enzymes, and proteases, whereas down-regulated gene families include the globulin genes and some steroidogenic genes. The expression of several growth factors changed during primordial follicle development, including vascular endothelial growth factor and insulin-like growth factor II. Elucidation of how these changes in gene expression coordinate primordial follicle assembly and the primordial to primary follicle transition provides a better understanding of these critical biological processes and allows selection of candidate regulatory factors for further investigation. Keywords: expression analysis, developmental time course, follicle assembly, ovary
Project description:This study compares miRNA expression profiles in mouse oocytes as young oocytes vs aged oocytes, and growing oocytes vs small oocytes from primordial follicles.
Project description:Progressive aging is associated with changes in sympathetic nervous system (SNS) regulation, suggesting an effect of advancing age on the functionality of central sympathetic premotor neurons. The rostral ventral lateral medulla (RVLM) contains sympathetic premotor neurons and plays a key role in SNS regulation, and it is plausible to speculate that age-related changes in the molecular mechanisms in the RVLM may contribute to alterations in SNS regulation. The present study tested the hypothesis that aging is associated with altered gene expression in the RVLM with emphasis on immune system associated gene transcripts. RVLM tissue punches from young, middle-aged, and aged F344 rats were analyzed using Agilent’s whole rat genome microarray. The RVLM gene expression profile varied with age and an association between chronological age and specific RVLM gene expression patterns was observed (p<0.05, FDR<0.3). Functional analysis of RVLM microarray data via gene ontology profiling and pathway analysis has identified up-regulation of genes associated with immune- and stress- related responses, and down-regulation of genes associated with lipid biosynthesis and neurotransmission in aged compared with middle-aged and young rats. Differentially expressed genes associated with complement system and microglial cells were further validated by quantitative PCR with separate RVLM samples (p<0.05, FDR<0.1). The present results are the first to demonstrate age-related changes in the RVLM molecular mechanisms, modifications that may provide the molecular backdrop for understanding immune-associated changes in SNS regulation.
Project description:The ovarian function decreases in parallel with aging. So do the quantity of follicles, which is about 1-2 million at birth, while only about 1000 primordial follicles are left at menopause. Folliculogenesis is vital for ovary function, no matter the synthesis of female hormones or ovulation, yet the mechanisms for its changing with increasing age are not fully understood. To further understand the age-related molecular changes in the process of folliculogenesis, we performed microarray gene expression profile analysis using total RNA extracted from young (9 weeks old) and old (32 weeks old) mouse ovarian secondary follicles. The results of our current microarray study revealed that there were 371 (≥2 fold, q-value ≤0.05) genes differentially expressed in which 174 genes were up-regulated and 197 genes were down-regulated in old mouse ovarian secondary follicles compared to young mouse ovarian secondary follicles. The gene ontology and KEGG pathway analysis of differentially expressed genes uncovered critical biological functions such as immune system process, aging, transcription, DNA replication, DNA repair, protein stabilization and apoptotic process were affected in the process of aging. The considerable changes in gene expression profile may have an adverse influence on follicle quality and folliculogenesis. Our study provided information on the processes that may contribute to age-related decline in ovarian function.
Project description:This dataset contains microarray data from normal controls (aged 20-99 yrs) and Alzheimer's disease cases, from 4 brain regions: hippocampus, entorhinal cortex, superior frontal cortex, post-central gyrus. Changes in expression of synaptic and immune related genes were analyzed, investigating age-related changes and AD-related changes, and region-specific patterns of change. These AD cases were processed simultaneously with the control cases (young and aged) included in GSE11882 (GSE11882 dataset contains data exclusively from normal control brains).
Project description:Female fertility is determined in part by the size and development of the primordial follicle pool. The current study investigates the role of glial cell-line derived neurotrophic factor (GDNF) in the regulation of primordial follicle development in the ovary. Ovaries from four-day old female rat pups were maintained in organ culture for ten days in the absence (control) or presence of GDNF or kit ligand/stem cell factor (KL). Ovaries treated with GDNF contained a significant increase in developing follicles, similar to that observed with KL treatment previously shown to promote follicle development. The actions of GDNF on the ovarian transcriptome were investigated with a microarray analysis. Immunohistochemical studies demonstrated that GDNF is localized to oocyte cytoplasm in follicles of all developmental stages, as well as to cumulus granulosa cells and theca cells in antral follicles. GDNF receptor alpha 1 (GFRalpha1) staining was localized to oocyte cytoplasm of primordial and primary follicles, and at reduced levels in oocytes of antral follicles. GFRalpha1 was present in mural granulosa cells of antral follicles, theca cells, and the ovarian surface epithelium. The localization studies were confirmed with molecular analysis. Microarray analysis was used to identify changes in the ovarian transcriptome and further elucidate the signaling network regulating early follicle development. Observations indicate that GDNF promotes primordial follicle development and mediates autocrine and paracrine cell-cell interactions required during folliculogenesis. In contrast to the testis, ovarian GDNF is predominantly produced by germ cells (oocytes) rather than somatic cells. Experiment Overall Design: RNA samples from two control groups (pooled untreated cultured ovaries) are compared to two treated groups (pooled cultured ovaries treated with GDNF)