Adeno-associated virus-mediated brain delivery of 5-lipoxygenase modulates the AD-like phenotype of APP mice

Abstract

BackgroundThe 5-lipoxygenase (5LO) enzymatic pathway is widely distributed within the central nervous system. Previous works showed that this protein is up-regulated in Alzheimer's disease (AD), and that its genetic absence results in a reduction of Amyloid beta (Aβ) levels in the Tg2576 mice.Here by employing an adeno-associated viral (AAV) vector system to over-express 5LO in the same mouse model, we examined its contribution to their cognitive impairments and brain AD-like amyloid pathology.ResultsOur results showed that compared with controls, 5LO-targeted gene brain over-expression in Tg2576 mice results in significant memory deficits. On the other hand, brain tissues had a significant elevation in the levels of Aβ peptides and deposition, no change in the steady state levels of amyloid-β precursor protein (APP), BACE-1 or ADAM-10, but a significant increase in PS1, nicastrin, and Pen-2, three major components of the γ-secretase complex. Additional data indicate that the transcription factor CREB was elevated and so were the mRNA levels for PS1, nicastrin and Pen-2.ConclusionsThese data demonstrate that neuronal 5LO plays a functional role in the pathogenesis of AD-like amyloidotic phenotype by modulating the γ-secretase pathway. They support the hypothesis that this enzyme is a novel therapeutic target for the treatment and prevention of AD.

GATA1‐mediated transcriptional regulation of the γ‐secretase activating protein increases Aβ formation in Down syndrome

“…N2A-APPswe cells were reverse transfected with siRNA (100nM) using Lipofectamine 2000 according to the manufacturer’s instruction and as previously described. 12,13 …”

“…12–14 Actin was always used as an internal loading control. Primary antibodies used were as follows: anti-GSAP full length (1:200) and GSAP-16kDa (1:150; Thermo Scientific, Waltham, MA), anti-TMP21 (1:200), anti-CD147(1:200), anti-APP N-terminal raised against amino acids 66 to 81 for total APP (1:200; Milli-pore, Billerica, MA), anti–ADAM-10 (1:200; Millipore), anti-PS1 (1:200; Cell Signaling Technology, Danvers, MA), anti–BACE-1 (1:200; IBL America, Minneapolis, MN), anti-nicastrin (1:200; Cell Signaling Technology), anti–Pen-2 (1:100; Invitrogen), anti–APH-1 (1:150; Millipore), anti-sAPPα (1:200; Cell Signaling Technology), anti-sAPP β (1:200; Cell Signaling Technology), anti–carboxyl-terminal fragments (CTFs; 1:200; Santa Cruz Biotechnology), anti–insulin-degrading enzyme (IDE; 1:200; Santa Cruz Biotechnology), anti-neprilysin (1:200; Santa Cruz Biotechnology), anti–apoli-poprotein E (apoE; 1:200), anti-GATA1 (1:200; Santa Cruz Biotechnology), anti-GATA2 (1:200; Santa Cruz Biotechnology), anti-JunD (1:200; Santa Cruz Biotechnology), anti–Ets-2 (1: 200; Santa Cruz Biotechnology), anti–caspase-3 (1:200; Santa Cruz Biotechnology), and anti– β -actin (1:200; Santa Cruz Biotechnology).…”

“…12–14 Briefly, mouse GSAP gene was amplified by using the corresponding primers (SA Biosciences, Valencia, CA), and β -actin was always used as an internal control gene.…”

Brain 5‐lipoxygenase over‐expression worsens memory, synaptic integrity, and tau pathology in the P301S mice

“…In the CNS, this protein is highly expressed in the cortex and hippocampus and localizes to both neuronal and glial cells (Manev et al ., 2000). Previously, we showed that 5LO acts as an endogenous modulator of Aβ formation in vitro and in vivo by influencing the development of the AD‐like phenotype in transgenic mouse models of the disease (Firuzi et al ., 2008; Chu & Praticò, 2011a; Chu et al ., 2012a; Giannopoulos et al ., 2014). More recently, we reported that selective pharmacological inhibition of 5LO activity ameliorates tau neuropathology and behavioral impairments of htau mice, a transgenic mouse model expressing wild‐type human tau (Giannopoulos et al ., 2015b).…”

Differential contribution of lipoxygenase isozymes to nigrostriatal vulnerability

“…The expression of LOX is enhanced in the brain with aging and in models of neurodegeneration and inflammation (Uz et al, 1998; Manev et al, 2000b; Qu et al, 2000; Firuzi et al, 2008; Basselin et al, 2010). Recent studies related to CNS disease have focused primarily on the 5- and 12/15-LOX isozymes (Chu and Pratico, 2011; Hashimoto, 2011; Manev et al, 2011; Puccio et al, 2011; Chu et al, 2012a,b). The LOX isozymes catalyze stereospecific modification of AA at either carbon position 5, 12 or 15 or both 12 and 15, and the site of molecular oxygen insertion correspondingly defines the isozyme (i.e.…”