• Animal cells and systems
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• v.4 no.4
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• pp.361-366
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• 2000

In order to investigate the role of protein kinase C (PKC) in chondrogenic differentiation, we examined the localization of PKC isoforms in a limb bud micromass culture system. PKC$\alpha$ is specifically localized in the regions which would become cartilage nodules, while PKC$\lambda/l$ and $\zeta$ display widespread distribution in the whole culture. Distribution of PKC$\alpha$ change along with promotion or inhibition of chondrogenesis by lysophosphatidylcholine or phorbol 12-myristate 13-acetate. On the other hand, localization of PKC$\lambda/l$ or $\zeta$ a was not changed by the modulation of chondrogenesis. Peanut agglutinin binding protein which is associated with cell aggregation during chondrogenesis was present in the cell condensation regions and its expression in those regions was influenced by PKC activity. Expression of fibronectin and N-cadherin in the cell condensing area were also affected by modulation of PKC activity. These results suggest involvement of PKC$\alpha$ in the cell condensation, possibly through regulating expression of fibronectin and N-cadherin.

• The Korean Journal of Zoology
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• v.34 no.4
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• pp.460-468
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• 1991

계배 limb bud간충직 연골원성 세포로부터 연골원세포로의 분화과정에서 Ca2+의 역할을 추구해 보기 위하여 Hamburger-Hamilton stage 23/24의 계배 limb bud간충직세포들을 미세배양법으로 배양하면서, Ca2+, calcium ionophore인 A23187, calcium channel blocker인 D600을 각각 농도 및 처리기간을 변화시켜 처리하면서 연골화의 정도를 검정하여, 연골세포 분화에 미치는 Ca2+의 작용양상을 분석하였다. 그 결과 Ca2+은 3 mM의 농도로 배양초기에 처리하였을 때 가장 효과적으로 연골화를 촉진하였으며, A23187(0.05 $\mu$ M) 처리는 세포내로 Ca2+유입을 증가시켜 연골화를 촉진시킨 반면, D6OO(30 $\mu$ M이하) 처리는 세포내로 Ca2+ 유입을 차단시킴으로서 연골화를 억제하는 것으로 나타났다. 이러한 결과에 따른 세포내로의 칼슘 유입 변화는 45Ca로 확인하였다. 그러므로 Ca2+에 의한 간충직세포의 연골세포로의 분화촉진 작용은 Ca2+이 연골화의 응집시기에 세포간의 접촉을 유도할 뿐만 아니라 배양 초기에 Ca2+이 세포 내로 들어감으로써 수반되는 일련의 기작에 의한 것임을 알았다.

• Journal of radiological science and technology
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• v.26 no.1
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• pp.91-97
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• 2003

The purpose of this study is to investigate the mechanism of inhibition of chondrogenic differentiation by X-irradiation. Cultures of chick limb bud mesenchymal cells were exposed to various dose of X-ray and chondrogenesis was examined. X-irradiation inhibited accumulation of proteoglycan based on the observation of alcian blue staining and expression of chondorcyte specific-type II collagen. X-irradiation also inhibited expression of protein kinase $C{\alpha}$ while expression of $PKC{\lambda}({\iota}),\;{\varepsilon}$ was not altered. Expression of Erk-1 was not changed by X-irradiation but phosphorylation of Erk-1 was increased. In addition, inhibition of Erk-1 phosphorylation by PD98059 overcame inhibitory effect of X-irradiation on the chondrogenic differentiation. PNA staining data showed that X-irradiation inhibited cellular aggregation. Taken together, these results suggest that X-irradiation inhibits chondrogenic differentiation by inhibiting cellular aggregation and suppressing expression of $PKC{\alpha}$ and promoting phosphorylation of Erk-1. In addition to above pathway, our results also suggest that X-irradiation may exerts its inhibitory effect by another signaling pathways.