Hinokitiol抑制大鼠血管平滑肌細胞增生之機轉探討

血小板衍生生長因子(platelet-derived growth factor-BB, PDGF-BB)造成血管平滑肌細胞的過度增生現象在粥狀動脈硬化以及血管相關的疾病中扮演重要角色。本篇論文在探討hinokitiol，扁柏類植物中的一種活性成分，抑制大鼠血管平滑肌細胞增生的分子機轉。Hinokitiol (4-isopropyltropolone, ??-thujaplicin)，係由扁柏類植物中所抽提出來具有抗腫瘤及殺菌作用的天然物，甚至可以預防掉髮和刺激毛髮生長。經由MTT assay，發現 hinokitiol (2, 5 ?嵱)以濃度相關性抑制PDGF-BB誘導血管平滑肌細胞的增生，而在相同濃度下並不影響未受刺激細胞的生長，使用顯微鏡觀察亦發現相同情形。而使用流式細胞儀偵測hinokitiol對血管平滑肌細胞生長週期的影響，發現hinokitiol (5 μM)會使細胞停留在G0/G1 phase，進而抑制細胞的增生。經由西方墨點法發現hinokitiol (2, 5 ?嵱)會抑制PDGF-BB誘導細胞增生抗原(PCNA)蛋白的表現，表示hinokitiol確實可以抑制DNA的合成。此外，在hinokitiol抑制PDGF-BB誘導血管平滑肌細胞增生的機轉方面，發現hinokitiol會抑制JNK，PLC??1，PKC substrates的磷酸化，而不影響Akt、ERK、p38的磷酸化。接下來的研究會朝hinokitiol抑制PDGF-BB誘導血管平滑肌細胞增生的機轉以及對細胞週期的影響再做進一步的探討。相信未來hinokitiol在預防粥狀動脈硬化及術後血管再窄化的疾病，應該是相當具有潛力的藥物。

關鍵字

扁柏醇；血管平滑肌細胞

並列摘要

Abnormal proliferation of vascular smooth muscle cell (VSMC) induced by platelet-derived growth factor (PDGF-BB) is a hallmark of atherosclerosis and related vascular disorders, although the pathogenic processes are quite different. Hence, the inhibition of VSMC proliferation deserves study. In this study, we investigated the inhibitory mechanisms of hinokitiol on VSMCs proliferation. Hinokitiol (4-isopropyltropolone, ??-thujaplicin), a compound found in the Hinoki cypress, Chamaecyparis obtusa, and the western red cedar, Thuja plicata Donhas with a variety of biological functions, including anti-tumor and anti-microbial. Even more fascinating, the compound can also prevent hair loss and up-regulate hair growth. MTT assay and microscopy observation revealed that hinokitiol (2, 5 ?嵱) inhibited PDGF-BB (10 ng/ml) induced vascular smooth muscle cells proliferation in a concentration dependent manner and did not affect the proliferation of unstimulated cell. We also found that hinokitiol (5 μM) inhibited cell cycle progression by arresting in the G0/G1 phase analyzed by flow cytometer. Western blot analysis showed that hinokitiol down-regulated proliferating cell nuclear antigen (PCNA) protein and inhibited PDGF-BB (10 ng/ml) induced DNA synthesis. Hinokitiol also inhibits PDGF-BB induced vascular smooth muscle cell proliferation through down-regulating the phosphorylation of c-Jun N-terminal kinase (JNK), phospholipase C-gamma 1 (PLC??1), protein kinase C substrates (PKC substrates). However, hinokitiol did not affect Akt, extracellular signal-regulated kinase (ERK) and p38 phosphorylation. Thus, overall the results demonstrate that hinokitiol is a promising inhibitor of VSMC proliferation and it may serve as a potential candidate for the prevention of atherosclerosis and restenosis. However, a further investigation will be needed to unravel the mechanism of hinokitiol on inhibition of PDGF-BB induced vascular smooth muscle cell proliferation and on molecular based regulation of cell cycle progression.

並列關鍵字

hinokitiol ； vascular smooth muscle cell

參考文獻

Abe, J., Deguchi, J., Takuwa, Y., Hara, K., Ikari, Y., Tamura, T., Ohno, M. & Kurokawa, K. 1998. Tyrosine phosphorylation of platelet derived growth factor beta receptors in coronary artery lesions: implications for vascular remodelling after directional coronary atherectomy and unstable angina pectoris. Heart 79: 400-6.

Ahmed, N. N., Grimes, H. L., Bellacosa, A., Chan, T. O. & Tsichlis, P. N. 1997. Transduction of interleukin-2 antiapoptotic and proliferative signals via Akt protein kinase. Proc Natl Acad Sci U S A 94: 3627-32.

Alessi, D. R., Caudwell, F. B., Andjelkovic, M., Hemmings, B. A. & Cohen, P. 1996. Molecular basis for the substrate specificity of protein kinase B; comparison with MAPKAP kinase-1 and p70 S6 kinase. FEBS Lett 399: 333-8.

Antoniades, H. N. 1981. Human platelet-derived growth factor (PDGF): purification of PDGF-I and PDGF-II and separation of their reduced subunits. Proc Natl Acad Sci U S A 78: 7314-7.

Aviv, A. 1994. Cytosolic Ca2+, Na+/H+ antiport, protein kinase C trio in essential hypertension. Am J Hypertens 7: 205-12.

國際替代計量

Hinokitiol抑制大鼠血管平滑肌細胞增生之機轉探討

全文下載

主題瀏覽