The synergistic regulatory effect of Runx2 and MEF transcription factors on osteoblast differentiation markers

PURPOSE: Bone tissues for clinical application can be improved by studies on osteoblast differentiation. Runx2 is known to be an important transcription factor for osteoblast differentiation. However, bone morphogenetic protein (BMP)-2 treatment to stimulate Runx2 is not sufficient to acquire enough bone formation in osteoblasts. Therefore, it is necessary to find other regulatory factors which can improve the transcriptional activity of Runx2. The erythroblast transformation-specific (ETS) transcription factor family is reported to be involved in various aspects of cellular proliferation and differentiation. METHODS: We have noticed that the promoters of osteoblast differentiation markers such as alkaline phosphatase (Alp), osteopontin (Opn), and osteocalcin (Oc) contain Ets binding sequences which are also close to Runx2 binding elements. Luciferase assays were performed to measure the promoter activities of these osteoblast differentiation markers after the transfection of Runx2, myeloid Elf-1-like factor (MEF), and Runxs+MEF. Reverse-transcription polymerase chain reaction was also done to check the mRNA levels of Opn after Runx2 and MEF transfection into rat osteoblast (ROS) cells. RESULTS: We have found that MEF, an Ets transcription factor, increased the transcriptional activities of Alp, Opn, and Oc. The addition of Runx2 resulted in the 2- to 6-fold increase of the activities. This means that these two transcription factors have a synergistic effect on the osteoblast differentiation markers. Furthermore, early introduction of these two Runx2 and MEF factors significantly elevated the expression of the Opn mRNA levels in ROS cells. We also showed that Runx2 and MEF proteins physically interact with each other. CONCLUSIONS: Runx2 interacts with MEF proteins and binds to the promoters of the osteoblast markers such as Opn nearby MEF to increase its transcriptional activity. Our results also imply that osteoblast differentiation and bone formation can be increased by activating MEF to elicit the synergistic effect of Runx2 and MEF.

The expressions of C-reactive protein and macrophage colony-stimulating factor in gingival tissue of human chronic periodontitis with hypertension / 대한치주과학회지

PURPOSE: The purpose of this study was to quantify and compare the expressions of CRP and M-CSF in the gingival tissues of the patients with chronic periodontitis associated to hypertension. METHODS: Gingival tissue samples were obtained during periodontal surgery or tooth extraction. Clinically healthy gingival tissue samples from systemically healthy 12 patients were categorized as group 1 (n=12). Inflammatory gingival tissue samples from patients with chronic periodontitis were categorized as group 2 (n=12). Inflammatory gingival tissue samples from patients with chronic periodontitis associated with hypertension were categorized as group 3 (n=12). Tissue samples were prepared and analyzed by Western blotting. The quantification of CRP and M-CSF were performed using a densitometer and statistically analyzed by one-way ANOVA followed by Tukey test. RESULTS: There were significant differences between group 1 and group 2 and between group 1 and group 3 in both CRP and M-CSF. The differences between group 2 and group 3 were not statistically significant in both proteins. However, the expression levels of CRP and M-CSF in hypertensive inflammatory gingiva showed increased tendency compared to non-hypertensive inflammatory gingiva. CONCLUSIONS: It is suggested that CRP and M-CSF might be used as inflammatory and bone resorption markers in periodontal diseased tissue. It is assumed that hypertension may be associated with the progression of periodontal inflammation and alveolar bone resorption.

Localization Patterns of Cytokeratin 1, 14 and PAX 9 in Mouse Embryonic Tongue Development / 체질인류학회지

Epithelial differentiation and morphogenesis in skin and oral mucosa were elucidated using various experimental tools. However, tongue epithelial differentiation has not been examined properly yet. In this study, we identified the relationship between morphological changes and localizations of differentiation markers, such as cytokeratins and PAX 9 in mice embryonic tongue development. Protective barrier formation and localization pattern of cytokeratins in tongue epithelium were examined with toluidine blue staining and immunohistochemistry respectively. Localization patterns of PAX 9 and Cytokeratin 14 were coincided during tongue epithelium development. In addition, compared with Ki67 localizations, marker for cell proliferation, localization patterns of PAX 9 and Cytokeratin 14 would suggest that these factors would involve in tongue barrier formation through cell proliferation. Based on these results, tongue epithelial differentiation would begin at E14 with the specific localizations of PAX 9 and Cytokeratin 14 prior to protective barrier formation then Cytokeratin 1, keratinization marker, would involve in protective barrier and filiform papillae formations.

Molecular Imaging Using Sodium Iodide Symporter (NIS) / 대한핵의학회잡지

Radioiodide uptake in thyroid follicular epithelial cells, mediated by a plasma membrane transporter, sodium iodide symporter (NIS), provides a first step mechanism for thyroid cancer detection by radioiodide injection and effective radioiodide treatment for patients with invasive, recurrent, and/or metastatic thyroid cancers after total thyroidectomy. NIS gene transfer to tumor cells may significantly and specifically enhance internal radioactive accumulation of tumors following radioiodide administration, and result in better tumor control. NIS gene transfers have been successfully performed in a variety of tumor animal models by either plasmid-mediated transfection or virus (adenovirus or retrovirus) -mediated gene delivery. These animal models include nude mice xenografted with human melanoma, glioma, breast cancer or prostate cancer, rats with subcutaneous thyroid tumor implantation, as well as the rat intracranial glioma model. In these animal models, non-invasive imaging of in vivo tumors by gamma camera scintigraphy after radioiodide or technetium injection has been performed successfully, suggesting that the NIS can serve as an imaging reporter gene for gene therapy trials. In addition, the tumor killing effects of I-131, ReO4-188 and At-211 after NIS gene transfer have been demonstrated in in vitro clonogenic assays and in vivo radioiodide therapy studies, suggesting that NIS gene can also serve as a therapeutic agent when combined with radioiodide injection. Better NIS-mediated imaging and tumor treatment by radioiodide requires a more efficient and specific system of gene delivery with better retention of radioiodide in tumor. Results thus far are, however, promising, and suggest that NIS gene transfer followed by radioiodide treatment will allow non-invasive in vivo imaging to assess the outcome of gene therapy and provide a therapeutic strategy for a variety of human diseases.