Mitochondria-targeted catalase reduces abnormal APP processing, amyloid ? production and BACE1 in a mouse model of Alzheimer's disease: implications for neuroprotection and lifespan extension.

ABSTRACT: The purpose of this study was to investigate the protective effects of the mitochondria-targeted antioxidant catalase (MCAT) and lifespan extension in mice that express amyloid beta (A?). Using immunoblotting and immunostaining analyses, we measured the production of full-length amyloid precursor protein (APP), soluble APP?, C-terminal fragments CTF99 and CTF83, monomeric and oligomeric A?, A? deposits and beta site amyloid precursor protein cleaving enzyme 1 (BACE1), in different stages of disease progression in MCAT/A?PP and A?PP mice. Using quantitative reverse transcriptase polymerase chain reaction and immunostaining analyses, we studied the expression of catalase, BACE1, the Alzheimer's disease (AD) markers, synaptophysin, APP, neprilysin, insulin-degrading enzyme and transthyretin in MCAT, A?PP, MCAT/A?PP and wild-type (WT) mice. Using the high pressure liquid chromatography analysis of 8-hydroxy-2-deoxyguanosine, we measured oxidative DNA damage in the cerebral cortical tissues from MCAT, A?PP, MCAT/A?PP and WT mice. We found that the A?PP transgenic mice that carried the human MCAT gene lived 5 months longer than did the A?PP mice. We also found that the overexpression of MCAT in the brain sections from the MCAT/A?PP transgenic mice significantly correlated with a reduction in the levels of full-length APP, CTF99, BACE1, A? levels (40 and 42), A? deposits and oxidative DNA damage relative to the brain sections from the A?PP mice. Interestingly, we found significantly increased levels of soluble APP? and CTF83 in the MCAT/A?PP mice, relative to the A?PP mice. These data provide direct evidence that oxidative stress plays a primary role in AD etiopathology and that in MCAT mice express A?, MCAT prevents abnormal APP processing, reduces A? levels and enhances A?-degrading enzymes in mice at different ages, corresponding to different stages of disease progression. These findings indicate that mitochondria-targeted molecules may be an effective therapeutic approach to treat patients with AD.

SUBMITTER: Mao P 

PROVIDER: S-EPMC3373244 | biostudies-literature | 2012 Jul

REPOSITORIES: biostudies-literature