scholarly journals Preclinical validation of a potent γ-secretase modulator for Alzheimer’s disease prevention

2021 ◽  
Vol 218 (4) ◽  
Author(s):  
Kevin D. Rynearson ◽  
Moorthi Ponnusamy ◽  
Olga Prikhodko ◽  
Yuhuan Xie ◽  
Can Zhang ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Safety Margin ◽  
Systemic Exposure ◽  
Secretase Activity ◽  
Adverse Effect Level ◽  
Prevention Studies ◽  
Effect Level ◽  
Multiple Species ◽  
Dose Dependent

A potent γ-secretase modulator (GSM) has been developed to circumvent problems associated with γ-secretase inhibitors (GSIs) and to potentially enable use in primary prevention of early-onset familial Alzheimer’s disease (EOFAD). Unlike GSIs, GSMs do not inhibit γ-secretase activity but rather allosterically modulate γ-secretase, reducing the net production of Aβ42 and to a lesser extent Aβ40, while concomitantly augmenting production of Aβ38 and Aβ37. This GSM demonstrated robust time- and dose-dependent efficacy in acute, subchronic, and chronic studies across multiple species, including primary and secondary prevention studies in a transgenic mouse model. The GSM displayed a >40-fold safety margin in rats based on a comparison of the systemic exposure (AUC) at the no observed adverse effect level (NOAEL) to the 50% effective AUC or AUCeffective, the systemic exposure required for reducing levels of Aβ42 in rat brain by 50%.

Selective Secretase Targeting for Alzheimer’s Disease Therapy

2021 ◽  
pp. 1-17
Author(s):  
Alvaro Miranda ◽  
Enrique Montiel ◽  
Henning Ulrich ◽  
Cristian Paz
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Amyloid Β ◽  
Amyloid Plaques ◽  
Neuroprotective Activity ◽  
Amyloid Β Protein ◽  
Secretase Activity ◽  
Membrane Bound ◽  
Aβ Production ◽  
Bace 1

Alzheimer’s disease (AD) is associated with marked atrophy of the cerebral cortex and accumulation of amyloid plaques and neurofibrillary tangles. Amyloid plaques are formed by oligomers of amyloid-β (Aβ) in the brain, with a length of 42 and 40 amino acids. α-secretase cleaves amyloid-β protein precursor (AβPP) producing the membrane-bound fragment CTFα and the soluble fragment sAβPPα with neuroprotective activity; β-secretase produces membrane-bound fragment CTFβ and a soluble fragment sAβPPβ. After α-secretase cleavage of AβPP, γ-secretase cleaves CTFα to produce the cytoplasmic fragment AICD and P3 in the non-amyloidogenic pathway. CTFβ is cleaved by γ-secretase producing AICD as well as Aβ in amyloidogenic pathways. In the last years, the study of natural products and synthetic compounds, such as α-secretase activity enhancers, β-secretase inhibitors (BACE-1), and γ-secretase activity modulators, have been the focus of pharmaceuticals and researchers. Drugs were improved regarding solubility, blood-brain barrier penetration, selectivity, and potency decreasing Aβ42. In this regard, BACE-1 inhibitors, such as Atabecestat, NB-360, Umibecestat, PF-06751979, Verubecestat, LY2886721, Lanabecestat, LY2811376, and Elenbecestat, were submitted to phase I-III clinical trials. However, inhibition of Aβ production did not recover cognitive functions or reverse the disease. Novel strategies are being developed, aiming at a partial reduction of Aβ production, such as the development of γ-secretase modulators or α-secretase enhancers. Such therapeutic tools shall focus on slowing down or minimizing the progression of neuronal damage. Here, we summarize structures and the activities of the latest compounds designed for AD treatment, with remarkable in vitro, in vivo, and clinical phase activities.

Genetic Variation in δ-Opioid Receptor Associates with Increased β- and γ-Secretase Activity in the Late Stages of Alzheimer’s Disease

2015 ◽  
Vol 48 (2) ◽  
pp. 507-516 ◽  
Author(s):  
Timo Sarajärvi ◽  
Mikael Marttinen ◽  
Teemu Natunen ◽  
Tarja Kauppinen ◽  
Petra Mäkinen ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Genetic Variation ◽  
Opioid Receptor ◽  
Secretase Activity ◽  
Δ Opioid Receptor ◽  
Late Stages

Dose-dependent effects of deprenyl on CSF monoamine metabolites in patients with Alzheimer's disease

1987 ◽  
Vol 91 (3) ◽  
pp. 293-296 ◽  
Author(s):  
T. Sunderland ◽  
P. N. Tariot ◽  
R. M. Cohen ◽  
P. A. Newhouse ◽  
A. M. Mellow ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Monoamine Metabolites ◽  
Dose Dependent

scholarly journals Macroautophagy—a novel β-amyloid peptide-generating pathway activated in Alzheimer's disease

2005 ◽  
Vol 171 (1) ◽  
pp. 87-98 ◽  
Author(s):  
W. Haung Yu ◽  
Ana Maria Cuervo ◽  
Asok Kumar ◽  
Corrinne M. Peterhoff ◽  
Stephen D. Schmidt ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cell Survival ◽  
Mammalian Target Of Rapamycin ◽  
Amyloid Peptide ◽  
Survival Pathways ◽  
Secretase Activity ◽  
Amyloid Aβ ◽  
Β Amyloid ◽  
Β Amyloid Peptide

Macroautophagy, which is a lysosomal pathway for the turnover of organelles and long-lived proteins, is a key determinant of cell survival and longevity. In this study, we show that neuronal macroautophagy is induced early in Alzheimer's disease (AD) and before β-amyloid (Aβ) deposits extracellularly in the presenilin (PS) 1/Aβ precursor protein (APP) mouse model of β-amyloidosis. Subsequently, autophagosomes and late autophagic vacuoles (AVs) accumulate markedly in dystrophic dendrites, implying an impaired maturation of AVs to lysosomes. Immunolabeling identifies AVs in the brain as a major reservoir of intracellular Aβ. Purified AVs contain APP and β-cleaved APP and are highly enriched in PS1, nicastrin, and PS-dependent γ-secretase activity. Inducing or inhibiting macroautophagy in neuronal and nonneuronal cells by modulating mammalian target of rapamycin kinase elicits parallel changes in AV proliferation and Aβ production. Our results, therefore, link β-amyloidogenic and cell survival pathways through macroautophagy, which is activated and is abnormal in AD.

Current Concepts in the Prevention of Alzheimer's Disease

CNS Spectrums ◽  
2003 ◽  
Vol 8 (11) ◽  
pp. 846-853 ◽  
Author(s):  
Mary Sano
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Observational Studies ◽  
Elderly Population ◽  
Primary And Secondary Prevention ◽  
Factors Associated ◽  
Significant Challenge ◽  
High Incidence ◽  
Prevention Studies ◽  
Very High

ABSTRACTAlzheimer's disease represents a significant challenge to the aging population. Since most estimates suggest that AD has a multifactorial etiology, the challenge to find preventative approaches is particularly great. With the aging of the population and the very high incidence from the eighth decade on, the challenge is further enhanced by the need to think of relatively safe interventions given the relative frailty of this elderly population. The need to find safe treatments, or ones with well-understood safety profiles, has led to the examination of known agents for potential dementia-preventing properties. Data supporting these interventions comes from observational studies, laboratory analyses, and clinical trials. Potential mechanisms for prevention of AD include anti-inflammatory and antioxidant approaches. Modulation of risk factors associated with cardiac disease may also reduce the risk of AD. Known agents have been examined for their potential to modify amyloid pathology. Trial designs to address prevention of AD include both primary and secondary prevention studies as well designs to assess slowing disease progression. Information can also be gathered when dementia evaluation is added to ongoing studies. As results from these studies becoming available, we will be able to refine our approach to managing this disease.

On the personal utility of Alzheimer’s disease-related biomarker testing in the research context

2018 ◽  
Vol 44 (12) ◽  
pp. 830-834 ◽  
Author(s):  
Eline M Bunnik ◽  
Edo Richard ◽  
Richard Milne ◽  
Maartje H N Schermer
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Information Provision ◽  
Research Participants ◽  
Personal Utility ◽  
Prevention Studies ◽  
Biomarker Testing ◽  
Asymptomatic Individuals ◽  
Ad Prevention ◽  
Explicit Request

Many healthy volunteers choose to take part in Alzheimer’s disease (AD) prevention studies because they want to know whether they will develop dementia—and what they can do to reduce their risk—and are therefore interested in learning the results of AD biomarker tests. Proponents of AD biomarker disclosure often refer to the personal utility of AD biomarkers, claiming that research participants will be able to use AD biomarker information for personal purposes, such as planning ahead or making important life decisions. In this paper, the claim that AD biomarkers have personal utility for asymptomatic individuals is critically assessed. It demonstrates that in the absence of clinical validity, AD biomarkers cannot have personal utility and do not serve research participants’ autonomy. Over the next few years, many research groups will be confronted with participants’ preferences to learn the results of AD biomarker tests. When researchers choose to make results available upon explicit request, they should ensure adequate information provision and education, notably on the uncertain clinical significance of AD biomarker information. Routine disclosure of AD biomarkers to cognitively unimpaired individuals in research settings cannot be justified with an appeal to the personal utility of AD biomarker information.

scholarly journals Green Tea Seed Isolated Theasaponin E1 Ameliorates AD Promoting Neurotoxic Pathogenesis by Attenuating Aβ Peptide Levels in SweAPP N2a Cells

Molecules ◽  
2020 ◽  
Vol 25 (10) ◽  
pp. 2334 ◽  
Author(s):  
Muhammad Imran Khan ◽  
Jin Hyuk Shin ◽  
Min Yong Kim ◽  
Tai Sun Shin ◽  
Jong Deog Kim
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Green Tea ◽  
Neuroblastoma Cells ◽  
Dependent Manner ◽  
Insulin Degrading Enzyme ◽  
App Processing ◽  
N2a Cells ◽  
Gene And Protein Expression ◽  
Dose Dependent

Alzheimer’s disease (AD) is the most frequent type of dementia affecting memory, thinking and behaviour. The major hallmark of the disease is pathological neurodegeneration due to abnormal aggregation of Amyloid beta (Aβ) peptides generated by β- and γ-secretases via amyloidogenic pathway. Purpose of the current study was to evaluate the effects of theasaponin E1 on the inhibition of Aβ producing β-, γ-secretases (BACE1, PS1 and NCT) and acetylcholinesterase and activation of the non-amyloidogenic APP processing α-secretase (ADAM10). Additionally, theasaponin E1 effects on Aβ degrading and clearing proteins neprilysin and insulin degrading enzyme (IDE). The effect of theasaponin E1 on these crucial enzymes was investigated by RT-PCR, ELISA, western blotting and fluorometric assays using mouse neuroblastoma cells (SweAPP N2a). theasaponin E1 was extracted and purified from green tea seed extract via HPLC, and N2a cells were treated with different concentrations for 24 h. Gene and protein expression in the cells were measured to determine the effects of activation and/or inhibition of theasaponin E1 on β- and γ-secretases, neprilysin and IDE. Results demonstrated that theasaponin E1 significantly reduced Aβ concentration by activation of the α-secretase and neprilysin. The activities of β- and γ-secretase were reduced in a dose-dependent manner due to downregulation of BACE1, presenilin, and nicastrin. Similarly, theasaponin E1 significantly reduced the activity of acetylcholinesterase. Overall, from the results it is concluded that green tea seed extracted saponin E1 possess therapeutic significance as a neuroprotective natural product recommended for the treatment of Alzheimer’s disease.

The proteins BACE1 and BACE2 and β-secretase activity in normal and Alzheimer's disease brain

2007 ◽  
Vol 35 (3) ◽  
pp. 574-576 ◽  
Author(s):  
J.H. Stockley ◽  
C. O'Neill
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Amyloid Β ◽  
Amyloid Β Peptide ◽  
Protein Levels ◽  
Rate Limiting Step ◽  
Secretase Activity ◽  
Aβ Amyloid ◽  
Ad Alzheimer’S Disease ◽  
And Function

The insidious progression of AD (Alzheimer's disease) is believed to be linked closely to the production, accumulation and aggregation of the ∼4.5 kDa protein fragment called Aβ (amyloid β-peptide). Aβ is produced by sequential cleavage of the amyloid precursor protein by two enzymes referred to as β- and γ-secretase. β-Secretase is of central importance, as it catalyses the rate-limiting step in the production of Aβ and was identified 7 years ago as BACE1 (β-site APP-cleaving enzyme 1). Soon afterwards, its homologue BACE2 was discovered, and both proteins represent a new subclass of the aspartyl protease family. Studies examining the regulation and function of β-secretase in the normal and AD brain are central to the understanding of excessive production of Aβ in AD, and in targeting and normalizing this β-secretase process if it has gone awry in the disease. Several reports indicate this, showing increased β-secretase activity in AD, with recent findings by our group showing changes in β-secretase enzyme kinetics in AD brain caused by an increased Vmax. This article gives a brief review of studies which have examined BACE1 protein levels and β-secretase activity in control and AD brain, considering further the expression of BACE2 in the human brain.

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