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Thymosin beta 4 is associated with RUNX2 expression through the Smad and Akt signaling pathways in mouse dental epithelial cells.

Someya H, Fujiwara H, Nagata K, Wada H, Hasegawa K, Mikami Y, Jinno A, Sakai H, Koyano K, Kiyoshima T - Int. J. Mol. Med. (2015)

Bottom Line: In previous studies by our group, we reported that thymosin beta 4 (Tb4) is closely associated with the initiation and development of the tooth germ, and can induce the expression of runt-related transcription factor 2 (RUNX2) during the development of the tooth germ.The protein expression of p-Smad1/5 and p-Akt in the mDE6 cells was reduced by treatment with Tb4-siRNA.This study provides putative information concerning the signaling pathway through which Tb4 induces RUNX2 expression, which may help to understand the regulation of tooth development and tooth regeneration.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Oral Pathology, Division of Maxillofacial Diagnostic and Surgical Sciences, Faculty of Dental Science, Kyushu University, Fukuoka 812-8582, Japan.

ABSTRACT
In previous studies by our group, we reported that thymosin beta 4 (Tb4) is closely associated with the initiation and development of the tooth germ, and can induce the expression of runt-related transcription factor 2 (RUNX2) during the development of the tooth germ. RUNX2 regulates the expression of odontogenesis-related genes, such as amelogenin, X-linked (Amelx), ameloblastin (Ambn) and enamelin (Enam), as well as the differentiation of osteoblasts during bone formation. However, the mechanisms through which Tb4 induces the expression of RUNX2 remain unknown. In the present study, we employed a mouse dental epithelial cell line, mDE6, with the aim to elucidate these mechanisms. The mDE6 cells expressed odontogenesis-related genes, such as Runx2, Amelx, Ambn and Enam, and formed calcified matrices upon the induction of calcification, thus showing characteristics of odontogenic epithelial cells. The expression of odontogenesis-related genes, and the calcification of the mDE6 cells were reduced by the inhibition of phosphorylated Smad1/5 (p-Smad1/5) and phosphorylated Akt (p-Akt) proteins. Furthermore, we used siRNA against Tb4 to determine whether RUNX2 expression and calcification are associated with Tb4 expression in the mDE6 cells. The protein expression of p-Smad1/5 and p-Akt in the mDE6 cells was reduced by treatment with Tb4-siRNA. These results suggest that Tb4 is associated with RUNX2 expression through the Smad and PI3K-Akt signaling pathways, and with calcification through RUNX2 expression in the mDE6 cells. This study provides putative information concerning the signaling pathway through which Tb4 induces RUNX2 expression, which may help to understand the regulation of tooth development and tooth regeneration.

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The results of the analysis of the signaling pathways upstream of runt-related transcription factor 2 (Runx2) expression in the mDE6 cells treated with siRNAs against thymosin beta 4 (Tb4). (A-D) The expression levels of (A) p-Smad1/5 and (B) p-Akt were decreased in the mDE6 cells treated with Tb4-siRNAs compared with those in control cells. Although the expression levels of (C) p-ERK1/2 and (D) β-catenin showed a tendency to be decreased in the mDE6 cells treated with Tb4-siRNAs, there were no significant differences observed. The data are the means ± SD from triplicate samples. *P<0.05 and **P<0.01 vs. Ut; and #P<0.05 and ##P<0.01 vs. Cont by a one-way ANOVA with the Tukey-Kramer comparison test.
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f5-ijmm-35-05-1169: The results of the analysis of the signaling pathways upstream of runt-related transcription factor 2 (Runx2) expression in the mDE6 cells treated with siRNAs against thymosin beta 4 (Tb4). (A-D) The expression levels of (A) p-Smad1/5 and (B) p-Akt were decreased in the mDE6 cells treated with Tb4-siRNAs compared with those in control cells. Although the expression levels of (C) p-ERK1/2 and (D) β-catenin showed a tendency to be decreased in the mDE6 cells treated with Tb4-siRNAs, there were no significant differences observed. The data are the means ± SD from triplicate samples. *P<0.05 and **P<0.01 vs. Ut; and #P<0.05 and ##P<0.01 vs. Cont by a one-way ANOVA with the Tukey-Kramer comparison test.

Mentions: We analyzed the effects of siRNA against Tb4 on the signaling pathways upstream of Runx2 expression in the mDE6 cells. The protein expression levels of p-Smad1/5 and p-Akt were significantly decreased in the Tb4-siRNA treated cells (Fig. 5A and B), although the degree of decrease varied depending on the siRNA used (siRNA-1, -2 and -3). No significant differences were observed in the expression levels of p-ERK1/2 and β-catenin between the Tb4-siRNA treated cells and the controls (Fig. 5C and D).


Thymosin beta 4 is associated with RUNX2 expression through the Smad and Akt signaling pathways in mouse dental epithelial cells.

Someya H, Fujiwara H, Nagata K, Wada H, Hasegawa K, Mikami Y, Jinno A, Sakai H, Koyano K, Kiyoshima T - Int. J. Mol. Med. (2015)

The results of the analysis of the signaling pathways upstream of runt-related transcription factor 2 (Runx2) expression in the mDE6 cells treated with siRNAs against thymosin beta 4 (Tb4). (A-D) The expression levels of (A) p-Smad1/5 and (B) p-Akt were decreased in the mDE6 cells treated with Tb4-siRNAs compared with those in control cells. Although the expression levels of (C) p-ERK1/2 and (D) β-catenin showed a tendency to be decreased in the mDE6 cells treated with Tb4-siRNAs, there were no significant differences observed. The data are the means ± SD from triplicate samples. *P<0.05 and **P<0.01 vs. Ut; and #P<0.05 and ##P<0.01 vs. Cont by a one-way ANOVA with the Tukey-Kramer comparison test.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4380193&req=5

f5-ijmm-35-05-1169: The results of the analysis of the signaling pathways upstream of runt-related transcription factor 2 (Runx2) expression in the mDE6 cells treated with siRNAs against thymosin beta 4 (Tb4). (A-D) The expression levels of (A) p-Smad1/5 and (B) p-Akt were decreased in the mDE6 cells treated with Tb4-siRNAs compared with those in control cells. Although the expression levels of (C) p-ERK1/2 and (D) β-catenin showed a tendency to be decreased in the mDE6 cells treated with Tb4-siRNAs, there were no significant differences observed. The data are the means ± SD from triplicate samples. *P<0.05 and **P<0.01 vs. Ut; and #P<0.05 and ##P<0.01 vs. Cont by a one-way ANOVA with the Tukey-Kramer comparison test.
Mentions: We analyzed the effects of siRNA against Tb4 on the signaling pathways upstream of Runx2 expression in the mDE6 cells. The protein expression levels of p-Smad1/5 and p-Akt were significantly decreased in the Tb4-siRNA treated cells (Fig. 5A and B), although the degree of decrease varied depending on the siRNA used (siRNA-1, -2 and -3). No significant differences were observed in the expression levels of p-ERK1/2 and β-catenin between the Tb4-siRNA treated cells and the controls (Fig. 5C and D).

Bottom Line: In previous studies by our group, we reported that thymosin beta 4 (Tb4) is closely associated with the initiation and development of the tooth germ, and can induce the expression of runt-related transcription factor 2 (RUNX2) during the development of the tooth germ.The protein expression of p-Smad1/5 and p-Akt in the mDE6 cells was reduced by treatment with Tb4-siRNA.This study provides putative information concerning the signaling pathway through which Tb4 induces RUNX2 expression, which may help to understand the regulation of tooth development and tooth regeneration.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Oral Pathology, Division of Maxillofacial Diagnostic and Surgical Sciences, Faculty of Dental Science, Kyushu University, Fukuoka 812-8582, Japan.

ABSTRACT
In previous studies by our group, we reported that thymosin beta 4 (Tb4) is closely associated with the initiation and development of the tooth germ, and can induce the expression of runt-related transcription factor 2 (RUNX2) during the development of the tooth germ. RUNX2 regulates the expression of odontogenesis-related genes, such as amelogenin, X-linked (Amelx), ameloblastin (Ambn) and enamelin (Enam), as well as the differentiation of osteoblasts during bone formation. However, the mechanisms through which Tb4 induces the expression of RUNX2 remain unknown. In the present study, we employed a mouse dental epithelial cell line, mDE6, with the aim to elucidate these mechanisms. The mDE6 cells expressed odontogenesis-related genes, such as Runx2, Amelx, Ambn and Enam, and formed calcified matrices upon the induction of calcification, thus showing characteristics of odontogenic epithelial cells. The expression of odontogenesis-related genes, and the calcification of the mDE6 cells were reduced by the inhibition of phosphorylated Smad1/5 (p-Smad1/5) and phosphorylated Akt (p-Akt) proteins. Furthermore, we used siRNA against Tb4 to determine whether RUNX2 expression and calcification are associated with Tb4 expression in the mDE6 cells. The protein expression of p-Smad1/5 and p-Akt in the mDE6 cells was reduced by treatment with Tb4-siRNA. These results suggest that Tb4 is associated with RUNX2 expression through the Smad and PI3K-Akt signaling pathways, and with calcification through RUNX2 expression in the mDE6 cells. This study provides putative information concerning the signaling pathway through which Tb4 induces RUNX2 expression, which may help to understand the regulation of tooth development and tooth regeneration.

Show MeSH
Related in: MedlinePlus