The development of novel therapeutic strategies for Alzheimer's disease (AD) represents one of the biggest unmet medical needs today. Application of neurotrophic factors able to modulate neuronal survival and synaptic connectivity is a promising therapeutic approach for AD. We aimed to determine whether the loco-regional delivery of ciliary neurotrophic factor (CNTF) could prevent amyloid-␤ (A␤) oligomer-induced synaptic damages and associated cognitive impairments that typify AD. To ensure long-term administration of CNTF in the brain, we used recombinant cells secreting CNTF encapsulated in alginate polymers. The implantation of these bioreactors in the brain of A␤ oligomer-infused mice led to a continuous secretion of recombinant CNTF and was associated with the robust improvement of cognitive performances. Most importantly, CNTF led to full recovery of cognitive functions associated with the stabilization of synaptic protein levels in the Tg2576 AD mouse model. In vitro as well as in vivo, CNTF activated a Janus kinase/signal transducer and activator of transcription-mediated survival pathway that prevented synaptic and neuronal degeneration. These preclinical studies suggest that CNTF and/or CNTF receptor-associated pathways may have AD-modifying activity through protection against progressive A␤-related memory deficits. Our data also encourage additional exploration of ex vivo gene transfer for the prevention and/or treatment of AD.

Soluble beta-amyloid (A␤) oligomers are considered to putatively play a critical role in the early synapse loss and cognitive impairment observed in Alzheimer's disease. We previously demonstrated that A␤ oligomers activate cytosolic phospholipase A 2 (cPLA 2 ), which specifically releases arachidonic acid from membrane phospholipids. We here observed that cPLA 2 gene inactivation prevented the alterations of cognitive abilities and the reduction of hippocampal synaptic markers levels noticed upon a single intracerebroventricular injection of A␤ oligomers in wild type mice. We further demonstrated that the A␤ oligomer-induced sphingomyelinase activation was suppressed and that phosphorylation of Akt/protein kinase B (PKB) was preserved in neuronal cells isolated from cPLA 2 Ϫ/Ϫ mice. Interestingly, expression of the A␤ precursor protein (APP) was reduced in hippocampus homogenates and neuronal cells from cPLA 2 Ϫ/Ϫ mice, but the relationship with the resistance of these mice to the A␤ oligomer toxicity requires further investigation. These results therefore show that cPLA 2 plays a key role in the A␤ oligomer-associated neurodegeneration, and as such represents a potential therapeutic target for the treatment of Alzheimer's disease.

Currently, the potential to interfere with the pathology of β-amyloid targeting a well-known drugable enzyme, the acetylcholinesterase (AChE), is opened. Peripheral or dual binding site inhibitors of AChE may simultaneously alleviate the cognitive and behavioral deficits in Alzheimer’s disease (AD) patients and, more importantly, act as disease-modifying agents delaying amyloid plaque formation. As part of a rational drug design program directed to find dual binding site AChE inhibitors, several families of compounds have been synthesized as potent AChE inhibitors. From these series, several drug candidates were selected based on their potent and selective inhibition of AChE (subnanomolar activity) and their interference with the β-amyloid aggregation in vitro (IC₅₀ in the low micromolar range). First in vivo data confirm our initial hypothesis. Oral treatment with NP-61 for 3 months is able to reverse the cognitive impairment (Morris water maze test) and to reduce plaque load in the brains of human amyloid precursor protein transgenic mice (Swedish mutation). These results suggest that NP-61, a potent β-amyloid modulator, is able to reverse the AD-like neurodegenerative phenotype in transgenic mice, indicating a promising disease-modifying agent for clinical application.

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Regulator of G-protein signaling 4 (RGS4), a member of the RGS family of proteins that inactivate G-proteins, has gained interest as a potential drug target for neurological disorders, such as epilepsy and Parkinson's disease (PD). In the case of PD, the main current options for alleviating motor symptoms are dopamine replacement therapies, which have limitations because of side effects and reduced effectiveness over the long term. Research on new nondopaminergic PD drug targets has indicated that inhibition of RGS4 could be an effective adjuvant treatment option. The effectiveness of RGS4 inhibition for an array of PD-linked functional and structural neuroprotection end points has not yet been demonstrated. Here, we use the 6-hydroxydopamine (6-OHDA) lesioning model of the nigrostriatal pathway in mice to address this question. We observe, using a battery of behavioral and pathological measures, that mice deficient for RGS4 are not protected from 6-OHDA-induced injury and show enhanced susceptibility in some measures of motor function. Our results suggest that inhibition of RGS4 as a nondopaminergic target for PD should be approached with caution.