Dipyridamole Induces Apoptosis by Inhibiting Akt Activation in Rat Mesangial Cells

Dipyridamole (Persantin)是一種常用來治療腎臟疾病的藥物。有抑制腎絲球環間膜細胞增生的功能。但是其機制尚未很明確，這種藥物的作用分成二個方向，其一是透過抑制非特異性phosphodiesterase，來累積細胞內的cAMP及cGMP；另一方面則是uncleoside transport inhibitor。在我們的實驗中，利用MTT Assay可以觀察到dipyridamole對培養的環間膜細胞生長有抑制的作用，藉著[(上標 3)H]thymideine incoporation的實驗，可發現經過dipyridamole處理的細胞其DNA合成量減少；但並未改變細胞釋出之LDH，因此dipyridamole所造成細胞數目減少並非necrosis之故；同時，經由流式細胞儀發現細胞週期停滯，且Sub-G1期細胞有增加的趨勢。在經過dipyridamole處理48小時之後，可以發現細胞有計劃性死亡(apoptosis)的特徵，例如DNA階梯化(laddering)、sub G1期的細胞增多及Bc1-2和Apaf-1的減少等。除此之外，我們發現dipyridamole處理過之環間膜細胞的Akt/PKB的磷酸化有減少的現象，所以由此結果推論，dipyridamole可能是經由透過抑制Akt/PKB的磷酸化來降低存活訊息而導致環間膜細胞的計劃性死亡。

關鍵字

Dipyridamole ；腎絲球環間膜細胞；細胞凋亡； Akt/PKB

並列摘要

Dipyridamole (persantin) is a nucleoside transport inhibitor and a non-specific phosphodiesterase inhibitor that increases intracellular levels of cAMP and cGMP through phosphodiesterase inhibition. Dipyridamole has been demonstrated to have an antiproliferative effect in glomerular mesangial cells. In the present study, we have confirmed that exposure of the mesangial cells to dipyridamole decreases the number of viable cells, as demonstrated by MTT assay. Dipyridamole suppressed [(superscript 3)H] thymidine incorporation into DNA and the reduction of viable cells are not due to toxicity because the LDH release from mesangial cells does not increase. Treatment of mesangial cells with dipyridamole arrests cell-cycle progression and increases the cell population at the sub G1 phase. Furthermore, incubation of mesangial cells with dipyridamole for 48 h induces characteristic features of apoptosis. The induction of mesangial cell apoptosis is correlated with Akt/PKB dephosphorylation and Bcl-2 down regulation. These data suggest that dipyridamole may block Akt/PKB phosphorylation and play a crucial role in the induction of apoptosis in rat mesangial cells.

並列關鍵字

Dipyridamole ； Mesangial cells ； Apoptosis ； Akt/PKB

國際替代計量

Dipyridamole Induces Apoptosis by Inhibiting Akt Activation in Rat Mesangial Cells

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