We used gene array analysis of cortical bone to identify Phex-dependent gene transcripts regulating Fgf23 production and mineralization in Hyp mice. We discovered that activation of Fgf receptor- and Wnt-pathways contribute to increased Ffg23 gene transcription in Hyp bone. We found evidence in Hyp bone for increased expression of Fgf1, Fgf7, and Egr2 in the Fgf-signaling pathway and decrements in Sost and Cpz and increments in Sfrp1 and 4 in the Wnt-signaling pathway. Moreover, activation of Fgf and Wnt-signaling stimulated, whereas Tgf inhibited Fgf23 promoter activity in osteoblasts. We also observed reductions in Bmp1, a metalloproteinase that metabolizes the Fgf23 regulatory extracellular matrix protein Dmp1. These findings suggest that elevation of Fgf23 expression in osteocytes is regulated by interactions between cell surface expression of Phex, extracellular matrix proteins and paracrine effects of Fgf and Wnt. Alterations were also found in enzymes regulating the posttranslational processing and stability of Fgf23, including decrements in the glycosyltransferase Galnt3 and the proprotein convertase Pcsk5. In addition, we found that the Pcsk5 and the glycosyltransferase Galnt3 were decreased in Hyp bone, suggesting that reduced post-translational processing of FGF23 may also contribute to increased Fgf23 levels in Hyp mice. With regards to mineralization, we identified additional candidates to explain the intrinsic mineralization defect in Hyp osteoblasts, including increases in the mineralization inhibitors Mgp and Thbs4, as well as increases in local pH altering factors, carbonic anhydrase 12 (Car12) and 3 (Car3) and the sodium-dependent citrate transporter (Slc13a5). These studies demonstrate the complexity of gene expression alterations in bone that accompanies inactivating Phex mutations and identify novel pathways that may coordinate Fgf23 expression and mineralization of extracellular matrix in Hyp bone.
Novel regulators of Fgf23 expression and mineralization in Hyp bone.
Sex, Age, Specimen part
View SamplesImmune deficiency is common in cancer, but the biological basis for this and ways to reverse it remains elusive. Here we present a mouse model of B cell chronic lymphocytic leukemia (CLL) that recapitulates changes in the non-malignant circulating T cells seen in patients with this illness.1 To validate this model, we examined changes in T cell gene expression, protein expression and function in Em-TCL1 transgenic mice as they developed CLL 2,3 and demonstrate that development of CLL in these transgenic mice is associated with changes in impaired T cell function and in gene expression in CD4 and CD8 T cells similar to those observed in patients with this disease. Infusion of CLL cells into non-leukemia bearing Em-TCL1 mice rapidly induces these changes, demonstrating a causal relationship between leukemia and the induction of T cell changes. This model allows dissection of the molecular changes induced in CD4 and CD8 T cells by interaction with leukemia cells and further supports the concept that cancer results in complex abnormalities in the immune microenvironment.
E(mu)-TCL1 mice represent a model for immunotherapeutic reversal of chronic lymphocytic leukemia-induced T-cell dysfunction.
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View SamplesWnt-4 signaling is critical for embryonic female sexual development. When Wnt-4 gene is deleted during embryonic development, the knock-out females present a partial sex reversal.
Identification of the genes regulated by Wnt-4, a critical signal for commitment of the ovary.
Specimen part
View SamplesActivation of the canonical Wnt signaling pathway is commonly observed in pancreatic cancer. We therefore sought to identify a gene expression profile associated with the activation of this pathway in pancreatic cancer cells.
Activation of WNT/β-Catenin Signaling Enhances Pancreatic Cancer Development and the Malignant Potential Via Up-regulation of Cyr61.
Specimen part, Cell line
View SamplesObjective Previous studies showed that genetic deletion or pharmacological blockade of the Receptor for Advanced Glycation Endproducts (RAGE) prevents the early structural changes in the glomerulus associated with diabetic nephropathy (DN). To overcome limitations of mouse models that lack the progressive glomerulosclerosis observed in humans, we studied the contribution of RAGE to DN in the OVE26 type 1 mouse, a model of progressive glomerulosclerosis and decline of renal function.
Deletion of the receptor for advanced glycation end products reduces glomerulosclerosis and preserves renal function in the diabetic OVE26 mouse.
Sex, Age, Specimen part, Disease, Disease stage
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