1.雌性素及雌性素接受體抑制Iso誘導細胞質鈣離子堆積及心肌細胞肥大之機轉；GSK-3β及I2PP2A與PP2A及PP1之相關性探討。 2.牛磺酸抑制膽固醇誘導先天性紅斑性狼瘡小鼠耗發心臟凋亡及纖維化。

1.17β-Estradiol and/or Estrogen Receptor α Inhibit Isoprotenerol-Induced Cytosolic Ca2+ accumulation & Cellular Hypertrophy in H9c2 Myocardiac Cells; Roles of GSK-3β, I2PP2A, PP2A and PP1. 2.Effects of Taurine on Cardiac Apoptosis and Fibrosis in NZB/W F1 Lupus Prone Mice

顏均宇(Chung-Yi Yen)

指導教授 ： 曾博修

中山醫學大學/醫學院/生化暨生物科技研究所/碩士(2008年)

摘要

1.雌性素及雌性素接受體抑制Iso誘導細胞質鈣離子堆積及心肌細胞
肥大之機轉；GSK-3β及I2PP2A與PP2A及PP1之相關性探討。
先前研究指出「男性較女性容易罹患左心室肥大」。且左心室肥大相關的
因子和年齡成正相關。然而女性停經以後罹患左心室肥大的比率卻暴增為男性
的好幾倍，說明了雌性素在預防左心室肥大的機轉中扮演著重要的角色。然而
，雌性素預防左心室肥大的詳細機轉尚未徹底了解。由於phosphatase曾被證實
參與β正腎上腺素引發的心臟肥大機轉。實驗室先前的研究採用isoproterenol
(Iso) 處理H9c2細胞來誘發心肌肥大。若同時在添加Iso之前處理雌性素或大量
表現雌性素接受體或兩者同時處理均可以有效抑制由Iso所誘導的心肌細胞肥大
及細胞質的鈣離子堆積。當我們進一步添加雌性素接受體的抑制劑(ICI)時，E2
及ER預防Iso誘發心肌肥大的能力則受到抑制。因此，我們得到一個結論即「
雌性素會透過雌性素接受體來達到預防Iso誘發心肌肥大的機制。」我們進一步
偵測肥大相關的BNP基因表現來證實Iso確實可以誘發心肌細胞產生肥大。同時
，我們也發現到PP2A會受到Iso活化並間接的去活化PP1並影響細胞內鈣離子流
，而雌性素及接受體則可抑制此現象達到預防的機制。我們同時發現PP2A可結
合至NCX，或直接影響細胞鈣離子的流動，與臨床上指出之病理性心臟疾病現
象相符合。我們的實驗中發現雌性素及接受體結合誘發GSK3-β大量表現並進而
而活化I2PP2A令大量表現，而I2PP2A被活化則可專一性的去抑制PP2A。綜合
我們的實驗結果，我們得知是「雌性素及接受體可阻斷由Iso所誘導之鈣離子堆
積及心肌肥大機制主要是透過結合活化GSK3-β進而活化I2PP2A，活化之
I2PP2A就可專一性抑制PP2A及PP1，進而阻斷細胞質的鈣離子堆積。」

2.牛磺酸抑制膽固醇誘導先天性紅斑性狼瘡小鼠耗發心臟凋亡及纖維化

 
 
 
 紅斑性狼瘡(SLE)是一種已經廣為人知由於自體免疫出錯的自體免疫疾病，
並且會引發許多不正常的免疫反應。但是，其所形成的原因以及其詳細的機轉
卻還未被透徹的了解及發現。然而已經有些研究指出可能造成或誘發SLE的原
因有：飲食、藥物和環境。更仔細的來說，例如飲食中若含有高膽固醇會造成
淺在帶有SLE的病患產生惡化。另一方面，由於SLE如前面所提及它會造成許
不正常的自體免疫反應。因此，許多身體的器官就會因此而受到嚴重的傷害，
例如：心臟和肝臟等等。臨床上的報告也指出SLE可能對心藏所造成的疾病可
能有：Pericarditis、Myocarditis和Endocarditis，其中SLE病患又以耗發粥狀動脈
硬化的比率最高。在我們的日常生活中可以發現到牛磺酸已經廣泛的存在我們
日的飲食之中，例如：運動飲料。而在早期就有研究指出牛磺酸可以用來減緩
膽固醇代謝出錯的情況，而在近期研究有人更利用細胞實驗指出牛磺酸可以用
來減緩由粥狀動脈硬化所產生的心肌細胞凋亡狀況。


 
 
 
 我們利用動物模式指出牛磺酸可以減緩由SLE所誘導的或是高膽固醇誘發
SLE惡化所產生的心肌細胞凋亡，而其主要的機轉是透過影響死亡受體接受器
這條訊息途徑。雖然我們並無發現牛磺酸對於心肌肥大有任何的影響，但是，
我們卻另外發現到牛磺酸還可以減緩SLE所誘導的或是高膽固醇誘發SLE惡化
所產生的心肌細胞纖維化的情況。因此，綜合上述，我們的實驗結果不僅可以
作為先前研究最好的動物模式反證。另一方面，也發現到牛磺酸也有減緩心臟
產生纖維化的能力。未來，希望能繼續的去探討牛磺酸對於其他一些由免疫產
生的傷害是否也有相同的抑制效果。

關鍵字

肥大 ； 心臟 ； 去磷酸酶PP2A

並列摘要

1.17β-Estradiol and/or Estrogen Receptor α Inhibit Isoprotenerol-Induced Cytosolic Ca2+ accumulation & Cellular Hypertrophy in H9c2 Myocardiac Cells; Roles of GSK-3β, I2PP2A, PP2A and PP1.

Women have lower prevalence of left ventricle hypertrophy (LVH) than men
has been well established. The occurrence of LVH increases progressively with age and becomes more common in women after menopause, which suggests that estrogen could prevent the development of cardiac hypertrophy. However, the cardioprotective mechanisms involving 17β-estradiol (E2) and estrogen receptor α (ERα) are obscure. Additionally, phosphatases are able to induce the cardiac hypertrophy through desensitising β-adrenergic signaling pathway. In present studies, H9c2 cardiac myocytes induced hypertrophy by isoproterenol (Iso), β-adrenergic receptor agonist. However, pre-administration of E2, doxycyclin (Dox) to induce ERα or E2 plus Dox, all of them significantly prevent Iso-induced cell size increase and cytosolic calcium accumulation. The hypertrophy marker BNP gene expression is also induced by the same treatment. Additionally, E2 action is totally reversed by estrogen receptors antagonist (ICI).
Previous reports show PP2A indirectly affects PP1 and intracellular calcium
flow. However, we found E2 and ERα pre-treatment totally prevent them. Recently, studies also indicate that the cardiac Na+-Ca2+ exchanger (NCX) plays an important role in pathological states acting as a major Ca2+ entry site during ischemia or reperfusion and PP2A play as the major regulator on it. In this study, we further discover that treated with E2, Dox or both, all induce GSK3-β and PP2A inhibitor2 (I2PP2A) over-expression. Further, the ability binding to NCX of PP2A also decreasing. Therefore, we rise the hypothesis that E2 and/or ERα disrupt the effect of PP2A to regulate
the calcium flow of NCX by strong induction of I2PP2A. Further evidences even show that E2 and ERα binding and active GSK3-β to up-regulating I2PP2A and disrupt PP2A activity, then maintain the normally calcium inflow. Collectively, E2 and ERα inhibit the myocardiac cells hypertrophy by preventing cytosolic calcium accumulation through GSK-3β & I2PP2A activation, then inhibit PP2A to active PP1 and suppress the association between PP2A and NCX.

2.Effects of Taurine on Cardiac Apoptosis and Fibrosis in NZB/W F1 Lupus Prone Mice
Systemic lupus erythematosus (SLE) has been known as autoimmune disease that causes an aberrant immune response. Although the cause and precise mechanism are still obscure, various studies indicated an association between dietary supplements and SLE, for example, high-cholesterol-diet induced cholesterolmia would deteriorate the disease activity in patients with SLE. Additionally, patients with SLE also develop various disorders that develop premature atherosclerosis likely associated with a combination of disease- and therapy-related factors, classic coronary artery disease (CAD) risk factors, genetic factors, or a combination of these. Notably, may studies have indicated that risk factors such as hypercholesterolemia present early in the course of the disease and are predictive of myocardial infarction, adverse renal outcomes, and mortality in patients with SLE.
Recently, experimental and clinical studies of the beneficial effect of taurine on pathologically changed function of the heart are shown. Moreover, the mechanisms of this effect both on the cellular and systemic level are also demonstrated. Taurine is known as the component of bile acid in liver of both animal and human and also the major amino acid in fish and crustacean. Taurine is also known to reduce the blood lipid, lipid oxidation and protect liver by increased detoxification. However, the effect of taurine on SLE is still unclear.
In this thesis, we demonstrated the reduced pathological change by histological analysis in the heart from NZB/W F1 mice that were fed with high-cholesterol diet and taurine as compared to those fed with high-cholesterol diet. Additionally, taurine reduced both Fas- and mitochondria- dependent apoptosis in heart of NZB/W F1 mice that were significantly induced by high-cholesterol diet as well as the reduced fibrosis including various inflammatory factors were revealed.

並列關鍵字

Hypertrophy ； Heart ； Protein Phosphatase 2A

參考文獻

hypertrophy. The Journal of clinical investigation. Mar 2005;115(3):527-537.

34. Hayashi M, Kobayashi H, Handa Y, Kawano H, Hirose S, Ishii H. Plateau-wave phenomenon (II). Occurrence of brain herniation in patients with and without plateau waves. Brain. Dec 1991;114 ( Pt 6):2693-2699.

1. Agabiti-Rosei E, Muiesan ML. Left ventricular hypertrophy and heart failure in women. J Hypertens Suppl. May 2002;20(2):S34-38.

2. Miya Y, Sumino H, Ichikawa S, Nakamura T, Kanda T, Kumakura H, Takayama Y, Mizunuma H, Sakamaki T, Kurabayashi M. Effects of hormone replacement therapy on left ventricular hypertrophy and growth-promoting factors in hypertensive postmenopausal women. Hypertens Res. Mar 2002;25(2):153-159.

3. Frey N, Olson EN. Cardiac hypertrophy: the good, the bad, and the ugly. Annual review of physiology. 2003;65:45-79.