Project description:Osteoblast differentiation leading to bone formation requires a coordinated transcriptional program. We have recently demonstrated that microtubule actin crosslinking factor 1 (MACF1) promotes osteoblast differentiation, suggesting a key role in regulating early-phase osteoblast differentiation. Here, we showed that the early-phase osteoblast differentiation transcriptome dynamics was regulated by MACF1 and the transcription of TCF7/LEF1, key effectors of Wnt signaling that is important for osteoblast differentiation was suppressed by MACF1 knockdown. Co-IP and Protein mass spectrometry revealed that MACF1 interacted with a known and two previously unknown repressors of TCF7/LEF1, DKK1, CDK12 and MEAF6. ChIP-seq analysis of MACF1-associated promoters further revealed that MACF1 interacted with transcription factors TCF12 and E2F6, which also suppressed the transcription of TCF7/LEF1. Furthermore, all these four MACF-interacted proteins inhibited osteoblast differentiation. By studying the underlying mechanism, we found that cytoplasmic-nuclear localization of MACF1 was dependent on its level and the cytoplasmic-nuclear localization of TCF12 and E2F6 was regulated by MACF1 localization. In addition, MACF1 oppositely regulated the transcription activity of TCF12 and TCF7. Current study, for the first time to our knowledge, suggest that MACF1 acts as a sponge of osteoblast differentiation repressors to promote osteoblast differentiation, and indicate a novel mechanism for regulating the cellular location of transcription factors by a protein associated with microtubule and actin.
Project description:Transitions between cell fates commonly occur in development and disease. The vascular endothelium is an essential contributor of osteoprogenitors to vascular calcification through endothelial-mesenchymal transitions, in which endothelial cells (ECs) gain plasticity and differentiate into osteoblast-like cells. Transcriptome profiling reveals transcriptional regulation in osteoblastic fate to endothelial differentiation.
Project description:Osteoblast differentiation leading to bone formation requires a coordinated transcriptional program. We have recently demonstrated that microtubule actin crosslinking factor 1 (MACF1) promotes osteoblast differentiation, suggesting a key role in regulating early-phase osteoblast differentiation. Here, we showed that the early-phase osteoblast differentiation transcriptome dynamics was regulated by MACF1 and the transcription of TCF7/LEF1, key effectors of Wnt signaling that is important for osteoblast differentiation was suppressed by MACF1 knockdown. Co-IP and Protein mass spectrometry revealed that MACF1 interacted with a known and two previously unknown repressors of TCF7/LEF1, DKK1, CDK12 and MEAF6. ChIP-seq analysis of MACF1-associated promoters further revealed that MACF1 interacted with transcription factors TCF12 and E2F6, which also suppressed the transcription of TCF7/LEF1. Furthermore, all these four MACF-interacted proteins inhibited osteoblast differentiation. By studying the underlying mechanism, we found that cytoplasmic-nuclear localization of MACF1 was dependent on its level and the cytoplasmic-nuclear localization of TCF12 and E2F6 was regulated by MACF1 localization. In addition, MACF1 oppositely regulated the transcription activity of TCF12 and TCF7. Current study, for the first time to our knowledge, suggest that MACF1 acts as a sponge of osteoblast differentiation repressors to promote osteoblast differentiation, and indicate a novel mechanism for regulating the cellular location of transcription factors by a protein associated with microtubule and actin.
Project description:Differentiation Time Course; examination of osteoblast differentation by comparing cells exposed to growth factors with ctrl cells. Keywords: other
Project description:The biological effects of 1?,25-dihydroxyvitamin D3 (1,25(OH)2D3) on osteoblast differentiation and function differ significantly depending upon the cellular state of maturation. To explore this phenomenon mechanistically, we examined the impact of 1,25(OH)2D3 on the transcriptomes of both pre-osteoblastic (POBs) and differentiated osteoblastic (OBs) MC3T3-E1 cells, and assessed localization of the vitamin D receptor (VDR) at sites of action on a genome-scale using ChIP-seq analysis. We observed that the 1,25(OH)2D3-induced transcriptomes of POBs and OBs were quantitatively and qualitatively different, supporting not only the altered biology observed but the potential for a change in VDR interaction at the genome as well. This idea was confirmed through discovery that VDR cistromes in POBs and OBs were also strikingly different. Depletion of VDR binding sites in OBs, due in part to reduced VDR expression, was the likely cause of the loss of VDR-target gene interaction. Continued novel regulation by 1,25(OH)2D3, however, suggested that factors in addition to the VDR might also be involved. Accordingly, we show that transcriptomic modifications are also accompanied by changes in genome binding of the master osteoblast regulator RUNX2 and the chromatin remodeler C/EBP?. Importantly, genome occupancy was also highlighted by the presence of epigenetic enhancer signatures which were selectively changed in response to both differentiation and 1,25(OH)2D3. The impact of VDR, RUNX2, and C/EBP? on osteoblast differentiation is exemplified by their actions at the Runx2 and Sp7 gene loci. We conclude that each of these mechanisms may contribute to the diverse actions of 1,25(OH)2D3 on differentiating osteoblasts. 4 transcription factors and 5 histone modifications were examined in undifferentiated MC3T3-E1 cells as well as post 15 day osteogenic differentiation MC3T3-E1 cells, which were treated for 3 hours prior to ChIP assay with ethanol vehicle or with 10-7M 1,25(OH)2D3. For the vehicle matched samples for RUNX2, CEBP beta and histones, please refer to study GSE41955. The samples were completed in biological replicate and examined separately.
Project description:The expression of Glis3 in C3H10T1/2 cells promotes osteoblastic differentiation as indicated by the the induction of increase in alkaline phosphatase activity, an early marker of osteoblast differentiation, and increased expression of osteopontin, a late marker of osteogenesis. Glis3 acts synergistically with bone morphogenic protein 2 (BMP-2). In contrast, expression of Glis3 inhibits the induction of adipocyte differentiation. Microarray analysis identified the fibroblast growth factor 18 (FGF18) as one of the genes induced by Glis3 in C3H10T1/2 cells directly. Keywords: Glis3, osteoblast differentiation, adipocyte differentiation, FGF18, BMP2
Project description:Differentiation of human skeletal stem cells (hMSC) into osteoblasts is regulated by a few well described transcription factors. Our study used clustering and gene expression data to identify a novel transcription factor. ZNF25, which we showed is involved in osteoblast differentiation. We used microarrays to study gene expression of hMSC-TERT4 cells during osteoblast differentiation.