• Molecules and Cells
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• 제43권2호
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• pp.160-167
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• 2020

Runt-related transcription factor 2 (RUNX2) is a key transcription factor for bone formation and osteoblast differentiation. Various signaling pathways and mechanisms that regulate the expression and transcriptional activity of RUNX2 have been thoroughly investigated since the involvement of RUNX2 was first reported in bone formation. As the regulation of Runx2 expression by extracellular signals has recently been reviewed, this review focuses on the regulation of post-translational RUNX2 activity. Transcriptional activity of RUNX2 is regulated at the post-translational level by various enzymes including kinases, acetyl transferases, deacetylases, ubiquitin E3 ligases, and prolyl isomerases. We describe a sequential and linear causality between post-translational modifications of RUNX2 by these enzymes. RUNX2 is one of the most important osteogenic transcription factors; however, it is not a suitable drug target. Here, we suggest enzymes that directly regulate the stability and/or transcriptional activity of RUNX2 at a post-translational level as effective drug targets for treating bone diseases.

• Nutrition Research and Practice
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• 제15권5호
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• pp.579-590
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• 2021

BACKGROUND/OBJECTIVES: Petasites japonicus Maxim (P. japonicus) has been used as an edible and medicinal plant and contains many bioactive compounds. The purpose of this study is to investigate the effect of P. japonicus on osteogenesis. MATERIALS/METHODS: The leaves and stems of P. japonicus were separated and extracted with hot water or ethanol, respectively. The total phenolic compound and total polyphenol contents of each extract were measured, and alkaline phosphatase (ALP) activity of each extract was evaluated to determine their effect on bone metabolism. To investigate the effect on osteoblast differentiation of the aqueous extract of P. japonicus leaves (AL), which produced the highest ALP activity among the tested extracts, collagen content was measured using the Sirius Red staining method, mineralization using the Alizarin Red S staining method, and osteocalcin production through enzyme-linked immunosorbent assay analysis. Also, real-time reverse transcription polymerase chain reaction was performed to investigate the mRNA expression levels of Runt-related transcriptional factor 2 (Runx2) and Osterix. RESULTS: Among the 4 P. japonicus extracts, AL had the highest values in all of the following measures: total phenolic compounds, total polyphenols, and ALP activity, which is a major biomarker of osteoblast differentiation. The AL-treated MC3T3-E1 cells showed significant increases in induced osteoblast differentiation, collagen synthesis, mineralization, and osteocalcin production. In addition, mRNA expressions of Runx2 and Osterix, transcription factors that regulate osteoblast differentiation, were significantly increased. CONCLUSIONS: These results suggest that AL can regulate osteoblasts differentiation, at least in part through Runx2 and Osterix. Therefore, it is highly likely that P. japonicus will be useful as an alternate therapeutic for the prevention and treatment of osteoporosis.

• IMMUNE NETWORK
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• 제16권3호
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• pp.176-182
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• 2016

CCR3 is a chemokine receptor that mediates the accumulation of allergic inflammatory cells, including eosinophils and Th2 cells, at inflamed sites. The regulatory sequence of the CCR3 gene, contains two Runt-related transcription factor (RUNX) 1 sites and two PU.1 sites, in addition to a functional GATA site for transactivation of the CCR3 gene. In the present study, we examined the effects of the cis-acting elements of RUNX1 and PU.1 on transcription of the gene in EoL-1 eosinophilic cells and Jurkat T cells, both of which expressed functional surface CCR3 and these two transcription factors. Introduction of RUNX1 siRNA or PU.1 siRNA resulted in a modest decrease in CCR3 reporter activity in both cell types, compared with transfection of GATA-1 siRNA. Cotransfection of the two siRNAs led to inhibition in an additive manner. EMSA analysis showed that RUNX1, in particular, bound to its binding motifs. Mutagenesis analysis revealed that all point mutants lacking RUNX1- and PU.1-binding sites exhibited reduced reporter activities. These results suggest that RUNX1 and PU.1 participate in transcriptional regulation of the CCR3 gene.

• 대한소아치과학회지
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• 제40권3호
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• pp.185-193
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• 2013

최근 유구치의 치수절단술 약제로 MTA의 임상 적용이 문헌들에서 보고된 바 있으나 MTA 표면에서 일어나는 유치 치수 세포의 반응에 대한 시험관내 연구는 많이 보고되지 않았다. 이번 연구의 목적은 유치 및 영구치에서 유래한 치수기질세포가 경화된 MTA 표면에서 나타내는 증식 및 분화 능력을 비교 평가하는 것이었다. 사람 영구치와 유치 치수 조직에서 분리된 치수기질세포를 경화된 MTA 표면에서 배양 후 세포증식율과 세포주기를 검사하였으며, 정량적 역전사 중합효소 연쇄반응(RT-PCR)을 사용하여 분화양상을 분석하였다. Runt-related transcription factor 2(Runx2)와 alkaline phosphatase(ALP)가 정량적 RT-PCR의 표지자로 사용되었고, MTA 표면에서 증식된 치수기질세포의 형태학적 변화를 주사전자현미경 하에서 관찰하였다. 영구치와 유치의 치수기질세포군은 세포증식률, 세포주기 분포 및 mRNA 발현 양상에 있어서 차이를 보이지 않았으며, 주사전자현미경 상에서 두 군 모두 수지상 형태를 나타내었다. MTA 상에서 관찰된 유치와 영구치의 치수기질세포의 비슷한 증식력 및 광화를 유도하는 세포로의 분화능은 유치의 치수절단술 제재로 MTA가 생체친화적으로 적합함을 보여준다.

• 대한소아치과학회지
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• 제29권3호
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• pp.337-344
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• 2002

조골 세포의 분화에 중요한 역할을 하는 전사 인자인 Runx2는 그 역할은 많이 알려져 있지만, 이를 조절하는 신호 전달체계에 대해서는 많이 알려지지 않았다. 이에 본 연구에서는 조골 세포의 분화 및 증식에 영향을 미친다고 알려진 PKC 및 MAPK pathway가 Runx2에 미치는 영향을 알아보고자 하였다. PKC활성화에 따른 Runx2의 전사 활성 및 발현 양상을 관찰하기 위해 6XOSE2-C2C12 cell에 PKC 활성제를 처리하여 luciferase assay와 Northern blot analysis를 시행하였다. MAPK 활성화에 따른 Runx2의 전사 활성을 관찰하기 위해 MAPK 활성제를 6XOSE2-C2C12 cell에 처리하여 luciferase assay를 시행하였다. 두 신호 전달 체계의 활성화에 따른 골 표지 유전자의 전사 양상을 관찰하기 위해 osteocalcin과 osteopontin을 transient transfection한 C2C12 cell에 각 신호 전달 체계의 활성제를 처리하여 luciferase assay를 시행하였다. 또한 각 신호 전달 체계가 상호 작용하는지 알아보기 위하여 MAPK 억제제를 전처리하여 MAPK pathway를 차단한 1 시간 뒤 PKC 활성제를 처리하고 luciferase assay를 시행하여 Runx2의 전사 활성을 관찰하였다. 이상의 실험으로 다음과 같은 결론을 얻었다. - PKC pathway의 활성화는 Runx2의 전사 활성 및 발현을 증가시키고 이로 인해 그의 영향을 받는 골 표지 유전자 (osteopontin, osteocalcin)의 전사도 증가한다. - MAPK pathway의 활성화는 Runx2 및 골 표지 유전자 (osteopontin, osteocalcin)의 전사활성을 증가시킨다. - PKC pathway는 MAPK pathway를 경유하여 Runx2의 전사 활성을 조절한다.

• Nutrition Research and Practice
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• 제10권2호
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• pp.148-153
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• 2016

BACKGROUND/OBJECTIVES: Bone formation and bone resorption continuously occur in bone tissue to prevent the accumulation of old bone, this being called bone remodeling. Osteoblasts especially play a crucial role in bone formation through the differentiation and proliferation. Therefore, in this study, we investigated the effects of Scytosiphon lomentaria extract (SLE) on osteoblastic proliferation and differentiation in MC3T3-E1 cells. MATERIALS/METHODS: A cell proliferation assay, alkaline phosphatase (ALP) activity assay, alizarin red staining and protein expression analysis of osteoblastic genes were carried out to assess the osteoblastic proliferation and differentiation. RESULTS: The results indicated that treatment of SLE promoted the proliferation of MC3T3-E1 cells and improved ALP activity. And, SLE treatment significantly promoted mineralized nodule formation compared with control. In addition, cells treated with SLE significantly upregulated protein expression of ALP, type 1 collagen, bone morphogenetic protein 2, runt-related transcription factor 2, osterix, and osteoprotegerin. CONCLUSIONS: The results demonstrate that SLE promote differentiation inducement and proliferation of osteoblasts and, therefore may help to elucidate the transcriptional mechanism of bone formation and possibly lead to the development of bone-forming drugs.