New Pathways Identify Novel Drug Targets for the Prevention and Treatment of Alzheimer's Disease.

Alzheimer's disease (AD) is an incurable, progressive neurodegenerative disorder. AD is a complex and multifactorial disease that is responsible for 60-80% of dementia cases. Aging, genetic factors, and epigenetic changes are the main risk factors for AD.

Effects of sub-chronic, in vivo administration of sigma-1 receptor ligands on platelet and aortic arachidonate cascade in streptozotocin-induced diabetic rats.

Background: Diabetes mellitus is a chronic metabolic disorder which induces endothelial dysfunction and platelet activation. Eicosanoids produced from arachidonic acid regulate cellular and vascular functions. Sigma-1 receptors (S1R) are expressed in platelets and endothelial cells and S1R expression is protective in diabetes.

Examination of Longitudinal Alterations in Alzheimer's Disease-Related Neurogenesis in an APP/PS1 Transgenic Mouse Model, and the Effects of P33, a Putative Neuroprotective Agent Thereon.

Neurogenesis plays a crucial role in cognitive processes. During aging and in Alzheimer's disease (AD), altered neurogenesis and neuroinflammation are evident both in C57BL/6J, APP/PS1 (Tg) mice and humans. AD pathology may slow down upon drug treatment, for example, in a previous study of our group P33, a putative neuroprotective agent was found to exert advantageous effects on the elevated levels of APP, Aβ, and neuroinflammation.

Effects of sub-chronic, in vivo administration of sigma non-opioid intracellular receptor 1 ligands on platelet and aortic arachidonate cascade in rats.

Platelets regulate cell-cell interactions and local circulation through eicosanoids from arachidonic acid. Sigma non-opioid intracellular receptor 1 (sigma-1 receptor) expressed in platelets and endothelial cells can regulate intracellular signalization. Our aim was to examine the influence of sub-chronic, in vivo-administered sigma-1 receptor ligands 2-morpholin-4-ylethyl 1-phenylcyclohexane-1-carboxylate (PRE-084); N-benzyl-2-[(1S)-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinolin-1-yl]ethan-1-amine; dihydrochloride, a new compound ((S)-L1); and N-[2-[4-methoxy-3-(2-phenylethoxy)phenyl]ethyl]-N-propylpropan-1-amine (NE-100) on the ex vivo arachidonic acid metabolism of the platelets and aorta of male rats.

Novel Therapeutic Target for Prevention of Neurodegenerative Diseases: Modulation of Neuroinflammation with Sig-1R Ligands.

Neurodegenerative diseases (NDDs) are characterized by progressive deterioration of the structure and function of cells and their networks in the nervous system. There are currently no drugs or other treatments that can stop the progression of NDDs. NDDs have many similarities and common pathways, e.

Impact of Two Neuronal Sigma-1 Receptor Modulators, PRE084 and DMT, on Neurogenesis and Neuroinflammation in an Aβ-Injected, Wild-Type Mouse Model of AD.

Alzheimer's disease (AD) is the most common form of dementia characterized by cognitive dysfunctions. Pharmacological interventions to slow the progression of AD are intensively studied. A potential direction targets neuronal sigma-1 receptors (S1Rs).

Novel High Affinity Sigma-1 Receptor Ligands from Minimal Ensemble Docking-Based Virtual Screening.

Sigma-1 receptor (S1R) is an intracellular, multi-functional, ligand operated protein that also acts as a chaperone. It is considered as a pluripotent drug target in several pathologies. The publication of agonist and antagonist bound receptor structures has paved the way for receptor-based in silico drug design.

Neuroinflammatory processes are augmented in mice overexpressing human heat-shock protein B1 following ethanol-induced brain injury.

Background: Heat-shock protein B1 (HSPB1) is among the most well-known and versatile member of the evolutionarily conserved family of small heat-shock proteins. It has been implicated to serve a neuroprotective role against various neurological disorders via its modulatory activity on inflammation, yet its exact role in neuroinflammation is poorly understood. In order to shed light on the exact mechanism of inflammation modulation by HSPB1, we investigated the effect of HSPB1 on neuroinflammatory processes in an in vivo and in vitro model of acute brain injury.

Heart-cutting two-dimensional liquid chromatography coupled to quadrupole-orbitrap high resolution mass spectrometry for determination of N,N-dimethyltryptamine in rat plasma and brain; Method development and application.

The orthogonal heart-cutting liquid chromatography (LC) modes coupled to high-resolution tandem mass spectrometry (HRMS/MS) provide a number of possibilities to enhance selectivity and sensitivity for the determination of targeted compounds in complex biological matricies. Here we report the development of a new fast 2D-LC-(HRMS/MS) method and its successful application for quantitative determination of the level of plasma and brain N,N-dimethyltriptamine (DMT) using α-methyltryptamine (AMT) as internal standard in an experimental model of cerebral ischemia/reperfusion using DMT administration. The 2D-LC separation was carried out by a combination of hydrophilic interaction liquid chromatography (HILIC) in the first dimension followed by second-dimensional reversed-phase (RP) chromatography within a total run time of 10 min.

Oligomerization and Conformational Change Turn Monomeric β-Amyloid and Tau Proteins Toxic: Their Role in Alzheimer's Pathogenesis.

The structural polymorphism and the physiological and pathophysiological roles of two important proteins, β-amyloid (Aβ) and tau, that play a key role in Alzheimer's disease (AD) are reviewed. Recent results demonstrate that monomeric Aβ has important physiological functions. Toxic oligomeric Aβ assemblies (AβOs) may play a decisive role in AD pathogenesis.

Effects of the Pentapeptide P33 on Memory and Synaptic Plasticity in APP/PS1 Transgenic Mice: A Novel Mechanism Presenting the Protein Fe65 as a Target.

Regulated intramembrane proteolysis (RIP) of the amyloid precursor protein (APP) leads to the formation of fragments, among which the intracellular domain of APP (AICD) was also identified to be a causative of early pathological events. AICD-counteracting proteins, such as Fe65, may serve as alternative therapeutic targets of Alzheimer's disease (AD). The detection of elevated levels of Fe65 in the brains of both human patients and APP transgenic mice may further strengthen the hypothesis that influencing the interaction between Fe65 and APP may have a beneficial effect on the course of AD.

Key Peptides and Proteins in Alzheimer's Disease.

Alzheimer's Disease (AD) is a form of progressive dementia involving cognitive impairment, loss of learning and memory. Different proteins (such as amyloid precursor protein (APP), β- amyloid (Aβ) and tau protein) play a key role in the initiation and progression of AD. We review the role of the most important proteins and peptides in AD pathogenesis.

Cerebrovascular Pathology in Hypertriglyceridemic APOB-100 Transgenic Mice.

Hypertriglyceridemia is not only a serious risk factor in the development of cardiovascular diseases, but it is linked to neurodegeneration, too. Previously, we generated transgenic mice overexpressing the human APOB-100 protein, a mouse model of human atherosclerosis. In this model we observed high plasma levels of triglycerides, oxidative stress, tau hyperphosphorylation, synaptic dysfunction, cognitive impairment, increased neural apoptosis and neurodegeneration.

The Role of Lipids and Membranes in the Pathogenesis of Alzheimer's Disease: A Comprehensive View.

Lipids participate in Amyloid Precursor Protein (APP) trafficking and processing - important factors in the initiation of Alzheimer's disease (AD) pathogenesis and influence the formation of neurotoxic β-amyloid (Aβ) peptides. An important risk factor, the presence of ApoE4 protein in AD brain cells binds the lipids to AD. In addition, lipid signaling pathways have a crucial role in the cellular homeostasis and depend on specific protein-lipid interactions.

Heat Shock Proteins and Autophagy Pathways in Neuroprotection: from Molecular Bases to Pharmacological Interventions.

Neurodegenerative diseases (NDDs) such as Alzheimer's disease, Parkinson's disease and Huntington's disease (HD), amyotrophic lateral sclerosis, and prion diseases are all characterized by the accumulation of protein aggregates (amyloids) into inclusions and/or plaques. The ubiquitous presence of amyloids in NDDs suggests the involvement of disturbed protein homeostasis (proteostasis) in the underlying pathomechanisms. This review summarizes specific mechanisms that maintain proteostasis, including molecular chaperons, the ubiquitin-proteasome system (UPS), endoplasmic reticulum associated degradation (ERAD), and different autophagic pathways (chaperon mediated-, micro-, and macro-autophagy).

Studies for Improving a Rat Model of Alzheimer's Disease: Icv Administration of Well-Characterized β-Amyloid 1-42 Oligomers Induce Dysfunction in Spatial Memory.

During the past 15 years, several genetically altered mouse models of human Alzheimer's disease (AD) have been developed. These costly models have greatly facilitated the evaluation of novel therapeutic approaches. Injecting synthetic β-amyloid (Aβ) 1-42 species into different parts of the brain of non-transgenic rodents frequently provided unreliable results, owing to a lack of a genuine characterization of the administered Aβ aggregates.

β-Amyloid and the Pathomechanisms of Alzheimer's Disease: A Comprehensive View.

Protein dyshomeostasis is the common mechanism of neurodegenerative diseases such as Alzheimer's disease (AD). Aging is the key risk factor, as the capacity of the proteostasis network declines during aging. Different cellular stress conditions result in the up-regulation of the neurotrophic, neuroprotective amyloid precursor protein (APP).

The Role of Sigma-1 Receptor, an Intracellular Chaperone in Neurodegenerative Diseases.

Background: Widespread protein aggregation occurs in the living system under stress or during aging, owing to disturbance of endoplasmic reticulum (ER) proteostasis. Many neurodegenerative diseases may have a common mechanism: the failure of protein homeostasis. Perturbation of ER results in unfolded protein response (UPR).

Dihydropyridine Derivatives Modulate Heat Shock Responses and have a Neuroprotective Effect in a Transgenic Mouse Model of Alzheimer's Disease.

Heat shock proteins (Hsps) have chaperone activity and play a pivotal role in the homeostasis of proteins by preventing misfolding, by clearing aggregated and damaged proteins from cells, and by maintaining proteins in an active state. Alzheimer's disease (AD) is thought to be caused by amyloid-β peptide that triggers tau hyperphosphorylation, which is neurotoxic. Although proteostasis capacity declines with age and facilitates the manifestation of neurodegenerative diseases such as AD, the upregulation of chaperones improves prognosis.

Mitochondrial Proteome Changes Correlating with β-Amyloid Accumulation.

Alzheimer's disease (AD) is a multifactorial disease of wide clinical heterogenity. Overproduction of amyloid precursor protein (APP) and accumulation of β-amyloid (Aβ) and tau proteins are important hallmarks of AD. The identification of early pathomechanisms of AD is critically important for discovery of early diagnosis markers.

New small-size peptides modulators of the exosite of BACE1 obtained from a structure-based design.

We report here two new small-size peptides acting as modulators of the β-site APP cleaving enzyme 1 (BACE1) exosite. Ac-YPYFDPL-NH2 and Ac-YPYDIPL-NH2 displayed a moderate but significant inhibitory effect on BACE1. These peptides were obtained from a molecular modeling study.

Protein Folding and Misfolding, Endoplasmic Reticulum Stress in Neurodegenerative Diseases: in Trace of Novel Drug Targets.

Alzheimer's disease (AD) is characterized by severe cognitive impairment and memory loss. AD is classified both into the "protein conformational" and the "endoplasmic reticulum-mitochondria stress" disorders. AD is a very complex, multifactorial disease of heterogeneous genetic and environmental background.

Dysfunction of Endoplasmic Reticulum (ER) and Mitochondria (MT) in Alzheimer's Disease: The Role of the ER-MT Cross-Talk.

A common feature of neurodegenerative diseases is the formation of misfolded, mostly enzyme resistant proteins. These substances may form toxic assemblies according to the current concept of the neurodegenerative diseases. Overlapping of the misfolded proteins is typical in these disorders.

Acute intracerebral treatment with amyloid-beta (1-42) alters the profile of neuronal oscillations that accompany LTP induction and results in impaired LTP in freely behaving rats.

Accumulation of amyloid plaques comprises one of the major hallmarks of Alzheimer's disease (AD). In rodents, acute treatment with amyloid-beta (Aβ; 1-42) elicits immediate debilitating effects on hippocampal long-term potentiation (LTP). Whereas LTP contributes to synaptic information storage, information is transferred across neurons by means of neuronal oscillations.

Structural and nanomechanical comparison of epitaxially and solution-grown amyloid β25-35 fibrils.

Aβ25-35, the fibril-forming, biologically active toxic fragment of the full-length amyloid β-peptide also forms fibrils on mica by an epitaxial assembly mechanism. Here we investigated, by using atomic force microscopy, nanomechanical manipulation and FTIR spectroscopy, whether the epitaxially grown fibrils display structural and mechanical features similar to the ones evolving under equilibrium conditions in bulk solution. Unlike epitaxially grown fibrils, solution-grown fibrils displayed a heterogeneous morphology and an apparently helical structure.