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Olivares-Navarrete R, Sutha K, Hyzy SL, Hutton DL, Schwartz Z, McDevitt T, Boyan BD. Osteogenic differentiation of stem cells alters vitamin D receptor expression. Stem Cells Dev 2012; 21:1726-35. [PMID: 22034957 DOI: 10.1089/scd.2011.0411] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Pluripotent and multipotent stem cells adopt an osteoblastic phenotype when cultured in environments that enhance their osteogenic potential. Embryonic stem cells differentiated as embryoid bodies (EBs) in osteogenic medium containing β-glycerophosphate exhibit increased expression of bone markers, indicating that cells are osteoblastic. Interestingly, 1α,25-dihydroxyvitaminD3 (1,25D) enhances the osteogenic phenotype not just in EBs but also in multipotent adult mesenchymal stem cells (MSCs). 1,25D acts on osteoblasts via classical vitamin D receptors (VDR) and via a membrane 1,25D-binding protein [protein disulfide isomerase family A, member 3 (PDIA3)], which activates protein kinase C-signaling. The aims of this study were to determine whether these receptors are regulated during osteogenic differentiation of stem cells and if stem cells and differentiated progeny are responsive to 1,25D. mRNA and protein levels for VDR, PDIA3, and osteoblast-associated proteins were measured in undifferentiated cells and in cells treated with osteogenic medium. Mouse EBs expressed both VDR and PDIA3, but VDR increased as cells underwent osteogenic differentiation. Human MSCs expressed Pdia3 at constant levels throughout differentiation, but VDR increased in cells treated with osteogenic medium. These results suggest that both 1,25D signaling mechanisms are important, with PDIA3 playing a greater role during early events and VDR playing a greater role in later stages of differentiation. Understanding these coordinated events provide a powerful tool to control pluripotent and multipotent stem cell differentiation through induction medium.
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Affiliation(s)
- Rene Olivares-Navarrete
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0363, USA
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Yuan X, Ta TC, Lin M, Evans JR, Dong Y, Bolotin E, Sherman MA, Forman BM, Sladek FM. Identification of an endogenous ligand bound to a native orphan nuclear receptor. PLoS One 2009; 4:e5609. [PMID: 19440305 PMCID: PMC2680617 DOI: 10.1371/journal.pone.0005609] [Citation(s) in RCA: 159] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2009] [Accepted: 04/22/2009] [Indexed: 12/25/2022] Open
Abstract
Orphan nuclear receptors have been instrumental in identifying novel signaling pathways and therapeutic targets. However, identification of ligands for these receptors has often been based on random compound screens or other biased approaches. As a result, it remains unclear in many cases if the reported ligands are the true endogenous ligands, – i.e., the ligand that is bound to the receptor in an unperturbed in vivo setting. Technical limitations have limited our ability to identify ligands based on this rigorous definition. The orphan receptor hepatocyte nuclear factor 4 α (HNF4α) is a key regulator of many metabolic pathways and linked to several diseases including diabetes, atherosclerosis, hemophilia and cancer. Here we utilize an affinity isolation/mass-spectrometry (AIMS) approach to demonstrate that HNF4α is selectively occupied by linoleic acid (LA, C18:2ω6) in mammalian cells and in the liver of fed mice. Receptor occupancy is dramatically reduced in the fasted state and in a receptor carrying a mutation derived from patients with Maturity Onset Diabetes of the Young 1 (MODY1). Interestingly, however, ligand occupancy does not appear to have a significant effect on HNF4α transcriptional activity, as evidenced by genome-wide expression profiling in cells derived from human colon. We also use AIMS to show that LA binding is reversible in intact cells, indicating that HNF4α could be a viable drug target. This study establishes a general method to identify true endogenous ligands for nuclear receptors (and other lipid binding proteins), independent of transcriptional function, and to track in vivo receptor occupancy under physiologically relevant conditions.
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Affiliation(s)
- Xiaohui Yuan
- Department of Gene Regulation and Drug Discovery, Gonda Diabetes Research Center, The Beckman Research Institute at the City of Hope National Medical Center, Duarte, California, United States of America
| | - Tuong Chi Ta
- Cell, Molecular and Developmental Biology Graduate Program, University of California Riverside, Riverside, California, United States of America
| | - Min Lin
- Department of Gene Regulation and Drug Discovery, Gonda Diabetes Research Center, The Beckman Research Institute at the City of Hope National Medical Center, Duarte, California, United States of America
| | - Jane R. Evans
- Department of Cell Biology and Neuroscience, University of California Riverside, Riverside, California, United States of America
| | - Yinchen Dong
- Department of Gene Regulation and Drug Discovery, Gonda Diabetes Research Center, The Beckman Research Institute at the City of Hope National Medical Center, Duarte, California, United States of America
| | - Eugene Bolotin
- Genetics, Genomics and Bioinformatics Graduate Program, University of California Riverside, Riverside, California, United States of America
| | - Mark A. Sherman
- Department of Biomedical Informatics, The Beckman Research Institute at the City of Hope National Medical Center, Duarte, California, United States of America
| | - Barry M. Forman
- Department of Gene Regulation and Drug Discovery, Gonda Diabetes Research Center, The Beckman Research Institute at the City of Hope National Medical Center, Duarte, California, United States of America
- * E-mail: (BMF); (FMS)
| | - Frances M. Sladek
- Department of Cell Biology and Neuroscience, University of California Riverside, Riverside, California, United States of America
- * E-mail: (BMF); (FMS)
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van den Bemd GJCM, Jhamai M, Brinkmann AO, Chang GTG. The atypical GATA protein TRPS1 represses androgen-induced prostate-specific antigen expression in LNCaP prostate cancer cells. Biochem Biophys Res Commun 2004; 312:578-84. [PMID: 14680804 DOI: 10.1016/j.bbrc.2003.10.154] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2003] [Indexed: 11/26/2022]
Abstract
Prostate-specific antigen (PSA) is considered as an important marker for prostate cancer. Regulation of PSA gene expression is mediated by androgens bound to androgen receptors via androgen response elements (AREs) in its promoter and far upstream enhancer regions. In addition, GATA proteins contribute to PSA gene transcription by interacting with GATA motifs present in the PSA enhancer sequence. The TRPS1 gene contains a single GATA zinc finger domain and not only binds to forward consensus GATA motifs but also to an inverse GATA motif overlapping the ARE III in the far upstream enhancer of the PSA gene. Overexpression of TRPS1 in androgen-dependent human LNCaP prostate cancer cells inhibited the transcription of a transiently transfected PSA enhancer/promoter-driven luciferase reporter construct. Furthermore, overexpression of TRPS1 reduced the androgen-induced endogenous PSA levels secreted in culture medium of LNCaP cells. Our results suggest a role of TRPS1 in androgen regulation of PSA gene expression.
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