阿茲海默症(Alzheimer’s disease, AD)的特徵之一為在細胞外堆積的amyloid beta peptide (Aβ)，Aβ是由類澱粉前驅蛋白(APP)的蛋白水解產生的全長為39~42個胺基酸。在AD患者中，粒線體的功能喪失可能和下列現象相關，造成神經細胞因為reactive oxygen species (ROS) 上升而死亡，以及粒線體損傷會釋放出細胞凋亡的開始因子。熱休克蛋白(Hsp)是生物體緩衝因環境溫度變化而造成傷害的一個重要機制。Hsp可以提高暴露在壓力環境下的細胞生存率。在我們研究中，我們分析內生性Aβ對基因轉殖APP695 wild-type (APPwt) 和 APP Swedish double mutation (APPsw)的中國倉鼠卵巢細胞(CHO)以及初代神經細胞的影響。我們使用染劑來偵測細胞內Ca2+、ROS和粒線體膜電位，而且使用ferrocytochrome c來測量cytochrome c oxidase的活性。我們發現當細胞處在內生性Aβ培養液時，細胞內Ca2+和ROS表現量增加、粒線體膜電位和cytochrome c oxidase活性下降。在西方墨點法中，我們發現了APP基因轉殖CHO細胞以及初代神經細胞，細胞色素C、Bax和Bid表現量會比control還多。我們發現APP基因轉殖CHO細胞以及初代神經細胞，Hsp90、HO-1表現量會增加。還發現在分離粒線體和細胞質後，Hsp90、Hsp60、HO-1和Hsp27在APP基因轉殖CHO細胞株的粒線體表現量都是上升趨勢。綜合實驗結果，我們的研究顯示，APP基因轉殖CHO細胞株(APPwt和APPsw)所表現的內生性Aβ，不論是在細胞株還是primary neuron都會使細胞內Ca2+和ROS上升，以及造成mitochondria內的MMP下降和cytochrome c oxidase表現減少，並且會誘導Hsp的表現。
Alzheimer’s disease (AD) is characterized by extracellular deposits of amyloid beta peptide (Aβ) and mitochondrial dysfunction in AD is perhaps relevant to these observations, as such contribute to neurodegenerative cell death through the formation of reactive oxygen species (ROS) and the release of molecules that initiate programmed cell death pathways. The heat shock protein (Hsps) increases survival after exposure to stressful conditions in nature. It is unclear that Aβ induces the mitochondrial dysfunction and the expression of Hsp. In our study, we analyzed the effects of endogenous Aβ on Chinese Hamster Ovary cells（CHO）cells transfected APP695 wild-type(APPwt) and APP Swedish double mutation (APPsw) and primary neuron. We used different dyes to detect Ca2+, ROS and mitochondrial membrane potential （MMP）level, and used ferrocytochrome c to perceive cytochrome c oxidase activity. We found elevated Ca2+ and ROS level, reduced MMP and cytochrome c oxidase activity in CHO cells transfected APPwt and APPsw and primary neuron. The pro-apoptosis proteins, cytochrome c, Bax, and Bid were increased in CHO cells transfected APPwt and APPsw and primary neuron co-culture with APPwt and APPsw conditioned medium. We also found that expressions of Hsp90 and Heme-Oxygenase-1（HO-1）were increased in CHO cells transfected APPwt and APPsw and primary neuron. The expression of Hsp90, Hsp60, HO-1 and Hsp27 were increased in mitochondria in CHO cells transfected APPwt and APPsw. Taken together, our results showed that endogenous Aβs could induce Ca2+ and ROS elevated level, MMP and cytochrome c oxidase activity reduced, and Hsp expressed.
