| First Author | Sakae N | Year | 2016 |
| Journal | J Neurosci | Volume | 36 |
| Issue | 13 | Pages | 3848-59 |
| PubMed ID | 27030769 | Mgi Jnum | J:231748 |
| Mgi Id | MGI:5774886 | Doi | 10.1523/JNEUROSCI.3757-15.2016 |
| Citation | Sakae N, et al. (2016) ABCA7 Deficiency Accelerates Amyloid-beta Generation and Alzheimer's Neuronal Pathology. J Neurosci 36(13):3848-59 |
| abstractText | In Alzheimer's disease (AD), the accumulation and deposition of amyloid-beta (Abeta) peptides in the brain is a central event. Abeta is cleaved from amyloid precursor protein (APP) by beta-secretase and gamma-secretase mainly in neurons. Although mutations inAPP,PS1, orPS2cause early-onset familial AD,ABCA7encoding ATP-binding cassette transporter A7 is one of the susceptibility genes for late-onset AD (LOAD), in which itsloss-of-functionvariants increase the disease risk. ABCA7 is homologous to a major lipid transporter ABCA1 and is highly expressed in neurons and microglia in the brain. Here, we show that ABCA7 deficiency altered brain lipid profile and impaired memory in ABCA7 knock-out (Abca7(-/-)) mice. When bred to amyloid model APP/PS1 mice, plaque burden was exacerbated by ABCA7 deficit.In vivomicrodialysis studies indicated that the clearance rate of Abeta was unaltered. Interestingly, ABCA7 deletion facilitated the processing of APP to Abeta by increasing the levels of beta-site APP cleaving enzyme 1 (BACE1) and sterol regulatory element-binding protein 2 (SREBP2) in primary neurons and mouse brains. Knock-down of ABCA7 expression in neurons caused endoplasmic reticulum stress highlighted by increased level of protein kinase R-like endoplasmic reticulum kinase (PERK) and increased phosphorylation of eukaryotic initiation factor 2alpha (eIF2alpha). In the brains of APP/PS1;Abca7(-/-)mice, the level of phosphorylated extracellular regulated kinase (ERK) was also significantly elevated. Together, our results reveal novel pathways underlying the association of ABCA7 dysfunction and LOAD pathogenesis. SIGNIFICANCE STATEMENT: Gene variants inABCA7encoding ATP-binding cassette transporter A7 are associated with the increased risk for late-onset Alzheimer's disease (AD). Importantly, we found the altered brain lipid profile and impaired memory in ABCA7 knock-out mice. The accumulation of amyloid-beta (Abeta) peptides cleaved from amyloid precursor protein (APP) in the brain is a key event in AD pathogenesis and we also found that ABCA7 deficit exacerbated brain Abeta deposition in amyloid AD model APP/PS1 mice. Mechanistically, we found that ABCA7 deletion facilitated the processing of APP and Abeta production by increasing the levels of beta-secretase 1 (BACE1) in primary neurons and mouse brains without affecting the Abeta clearance rate in APP/PS1 mice. Our study demonstrates a novel mechanism underlying how dysfunctions of ABCA7 contribute to the risk for AD. |
