Several studies have shown that bone mineral density (BMD), a clinically measurable predictor of osteoporotic fracture, is the sum of genetic and environmental influences. In addition, serum IGF-1 levels have been correlated to both BMD and fracture risk. We previously identified a Quantitative Trait Locus (QTL) for Bone Mineral Density (BMD) on mouse Chromosome (Chr) 6 that overlaps a QTL for serum IGF-1. The B6.C3H-6T (6T) congenic mouse is homozygous for C57BL/6J (B6) alleles across the genome except for a 30 cM region on Chr 6 that is homozygous for C3H/HeJ (C3H) alleles. This mouse was created to study biology behind both the BMD and the serum IGF-1 QTLs and to identify the gene(s) underlying these QTLs. Female 6T mice have lower BMD and lower serum IGF-1 levels at all ages measured. As the liver is the major source of serum IGF-1, we examined differential expression in the livers of fasted female B6 and 6T mice by microarray.
A chromosomal inversion within a quantitative trait locus has a major effect on adipogenesis and osteoblastogenesis.
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View SamplesBeyond demonstrating a critical role for progesterone receptor signaling in normal mammary epithelial proliferation, the progesterone receptor knockout mouse disclosed the progesterone receptor along with its effector pathways as key determinants of mammary neoplastic progression. Despite these advances, however, further progress in our mechanistic understanding of progesterones involvement in mammary morphogenesis and tumorigenesis is contingent upon defining the essential effector pathways responsible for transducing the progesterone signal into a mammary proliferative and/or pro-survival response. Toward this goal, a judiciously chosen acute progesterone treatment regimen together with microarray methods was applied to the mammary gland of the normal mouse to uncover new effectors that operate immediately downstream of the progesterone mammary signal. Examination of the resultant progesterone-responsive transcriptome disclosed inhibitor of differentiation or DNA binding 4 (Id4) as a molecular target acutely induced by progesterone in the murine mammary epithelium.
Transcriptional response of the murine mammary gland to acute progesterone exposure.
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View SamplesThe small G-protein KRAS is crucial for mediating gonadotropin-induced events associated with ovulation. However, constitutive expression of KrasG12D in granulosa cells disrupted normal follicle development leading to the persistence of abnormal follicle-like structures containing non-mitotic cells. To determine what factors mediate this potent effect of KrasG12D, gene profiling analyses were done. We also analyzed KrasG12D;Cyp19-Cre and KrasG12D;Pgr-Cre mutant mouse models that express Cre prior to or after the initiation of granulosa cell differentiation, respectively. KrasG12D induced cell cycle arrest in granulosa cells of the KrasG12D;Cyp19-Cre mice but not in the KrasG12D;Pgr-Cre mice, documenting the cell context specific effect of KrasG12D. Expression of KrasG12D silenced the Kras gene, reduced cell cycle activator genes and impaired expression of granulosa cell and oocyte specific genes. Conversely, levels of PTEN and phosphorylated p38MAPK increased markedly in the mutant granulosa cells. Because disrupting Pten in granulosa cells leads to increased proliferation and survival, Pten was disrupted in the KrasG12D mutant mice. The Pten/Kras mutant mice were infertile but lacked GCTs. By contrast, the Ptenfl/fl;KrasG12D;Amhr2-Cre mice developed aggressive ovarian surface epithelial (OSE) cell tumors that did not occur in the Ptenfl/fl;KrasG12D;Cyp19-Cre or Ptenfl/fl;KrasG12D;Pgr-Cre mouse strains. These data document unequivocally that Amhr2-Cre is expressed in and mediates allelic recombination of oncogenic genes in OSE cells. That KrasG12D/Pten mutant granulosa cells do not transform but rather undergo cell cycle arrest indicates that they resist the oncogenic insults of Kras/Pten by robust self-protecting mechanisms that silence the Kras gene and elevate PTEN and phospho-p38MAPK.
Cell type-specific targeted mutations of Kras and Pten document proliferation arrest in granulosa cells versus oncogenic insult to ovarian surface epithelial cells.
Age, Specimen part
View SamplesTo study the physiological role of WNT4 in the postnatal ovary, a mouse strain bearing a floxed Wnt4 allele was created and mated to the Amhr2tm3(cre)Bhr strain to target deletion of Wnt4 to granulosa cells. Wnt4flox/-;Amhr2tm3(cre)Bhr/+ mice had significantly reduced ovary weights and produced smaller litters (P<0.05). Serial follicle counting demonstrated that, while Wnt4flox/-;Amhr2tm3(cre)Bhr/+ mice were born with a normal ovarian reserve and maintained normal numbers of small follicles until puberty, they had only 25.2% of the normal number of healthy antral follicles. Some Wnt4flox/-;Amhr2tm3(cre)Bhr/+ mice had no antral follicles or corpora lutea and underwent premature follicle depletion. RTPCR analyses of Wnt4flox/-;Amhr2tm3(cre)Bhr/+ granulosa cells and cultured granulosa cells that overexpress WNT4 demonstrated that WNT4 regulates the expression of Star, Cyp11a1 and Cyp19, steroidogenic genes previously identified as downstream targets of the WNT signaling effector CTNNB1. WNT4- and CTNNB1-overexpressing cultured granulosa cells were analyzed by microarray for alterations in gene expression, which showed that WNT4 also regulates a series of genes involved in late follicle development and the cellular stress response via the WNT/CTNNB1 signaling pathway. Together, these data indicate that WNT4 is required for normal antral follicle development, and may act by regulating granulosa cell functions including steroidogenesis.
WNT4 is required for normal ovarian follicle development and female fertility.
Specimen part, Treatment
View SamplesSRC-2 is frequently amplified or overexpressed in metastatic prostate cancer patients. In this study, we used genetically engineered mice, overexpressing SRC-2 specifically in the prostate epithelium as a mouse model to examine the role of SRC-2 in prostate tumorigenesis. Over-expression of SRC-2 in PTEN heterozygous mice accelerates PTEN mutation induced tumor progression and develops a metastasis-prone cancer.
Androgen deprivation-induced NCoA2 promotes metastatic and castration-resistant prostate cancer.
Age, Specimen part
View SamplesThe molecular targets of SRC-2 regulation in the murine liver stimulate fatty acid degradation and glycolytic pathway while fatty acid, cholesterol, and steroid biosynthetic pathways are down-regulated.
The genomic analysis of the impact of steroid receptor coactivators ablation on hepatic metabolism.
Sex, Specimen part
View SamplesOur previous study revealed that the basic helix-loop-helix transcription factor Hand2 is a downstream target of progesterone signaling in mouse uterine stroma at the time of implantation. Further, conditional deletion of Hand2 in mouse uterus leads to implantation failure due to impaired uterine epithelial receptivity.
The antiproliferative action of progesterone in uterine epithelium is mediated by Hand2.
Specimen part, Disease
View SamplesIn order to gain a better understanding of Ihh action during embryo implantation, we constitutively activated Smo in the murine uterus using the PRcre mouse model (PRcre/+SmoM2+; SmoM2). Female SmoM2 mice were infertile. They exhibited normal serum progesterone levels and normal ovulation, but ova failed to be fertilized in vivo and the uterus failed to undergo the artificially induced decidual response. SmoM2 mice exhibited uterine hypertrophy. The endometrium had a reduced number of uterine glands and the endometrial stroma lost its normal morphologic characteristics. Microarray analysis of 3 month old SmoM2 uteri demonstrated a chondrocytic signature and confirmed that constitutive activation of SmoM2 increased extracellular matrix production. Thus, constitutive activation of Smo in the mouse uterus alters the extracellular matrix which interferes with early pregnancy.
Constitutive activation of smoothened leads to female infertility and altered uterine differentiation in the mouse.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
A Gata2-Dependent Transcription Network Regulates Uterine Progesterone Responsiveness and Endometrial Function.
Sex, Age, Specimen part, Treatment
View SamplesEpithelial organs including the lung are known to possess regenerative abilities through activation of endogenous stem cell populations but the molecular pathways regulating stem cell expansion and regeneration are not well understood. Here we show that Gata6 regulates the temporal appearance and number of bronchioalveolar stem cells (BASCs) in the lung leading to the precocious appearance of BASCs and concurrent loss in epithelial differentiation in Gata6 null lung epithelium. This expansion of BASCs is the result of a dramatic increase in canonical Wnt signaling in lung epithelium upon loss of Gata6. Expression of the non-canonical Wnt receptor Fzd2 is down-regulated in Gata6 mutants and increased Fzd2 or decreased -catenin expression rescues, in part, the lung epithelial defects in Gata6 mutants. During lung epithelial regeneration, we show that canonical Wnt signaling is activated in the niche containing BASCs and forced activation of Wnt signaling leads to a dramatic increase in BASC numbers. Moreover, Gata6 is required for proper lung epithelial regeneration and postnatal loss of Gata6 leads to increased BASC expansion and decreased differentiation. Together, these data demonstrate that Gata6 regulated Wnt signaling controls the balance between stem/progenitor expansion and epithelial differentiation required for both lung development and regeneration.
A Gata6-Wnt pathway required for epithelial stem cell development and airway regeneration.
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