Tau aggregation inhibitors: the future of Alzheimer’s pharmacotherapy?

Advances in nanotechnology-assisted photodynamic therapy for neurological disorders: a comprehensive review

Neurological disorders such as neurodegenerative diseases and nervous system tumours affect more than one billion people throughout the globe. The physiological sensitivity of the nervous tissue limits the application of invasive therapies and leads to poor treatment and prognosis. One promising solution that has generated attention is Photodynamic therapy (PDT), which can potentially revolutionise the treatment landscape for neurological disorders. PDT attracted substantial recognition for anticancer efficacy and drug conjugation for targeted drug delivery. This review thoroughly explained the basic principles of PDT, scientific interventions and advances in PDT, and their complicated mechanism in treating brain-related pathologies. Furthermore, the merits and demerits of PDT in the context of neurological disorders offer a well-rounded perspective on its feasibility and challenges. In conclusion, this review encapsulates the significant potential of PDT in transforming the treatment landscape for neurological disorders, emphasising its role as a non-invasive, targeted therapeutic approach with multifaceted applications.

Neuroprotective effects of oleuropein: Recent developments and contemporary research

Neurological disorders are increasing at a faster pace due to oxidative stress, protein aggregation, excitotoxicity, and neuroinflammation. It is reported that the Mediterranean diet including olives as a major dietary component prevents and ameliorates neurological anomalies. Oleuropein is the major bioactive component in different parts of the Olive (Olea europaea L.) tree. Several mechanisms have been reported for the neuroprotective role of oleuropein including induction of apoptosis and autophagy, enhancing the antioxidant pool of the cerebral region, decreasing the unnecessary release of proinflammatory cytokines and chemokines by deactivating the microglia cells and astrocytes thus preventing the occurrence of neuroinflammation. Regular intake of oleuropein seems to be correlated with decreased risks of neural disorders including Alzheimer's, Parkinson's, strokes, depression, anxiety, epilepsy, and others. This review majorly discusses the chemistry, biosynthesis, and metabolism of oleuropein along with an updated vision of its neuroprotective role in counteracting the acute and chronic neurodegenerative and neuropsychiatric disorders. Moreover, mechanisms by which oleuropein may prevent neurodegeneration are reviewed. PRACTICAL APPLICATION: Neurological disorders are negatively affecting the health and life quality of individuals around the globe. Although various medicinal solutions are available to tackle such ailments, none has proven to fully cure and being deprived of side effects. In this respect, the prevention of such disorders using natural remedies may be an effective strategy to overcome the incidence of the increasing cases. Furthermore, the natural compounds provide a safer alternative to pharmaceutical drugs. Hence, oleuropein from olive tree products is found to be efficacious against neurological disorders. This review provides an updated insight on the positive effects of oleuropein against neurodegenerative and neuropsychiatric disorders. The diet practitioners and nutraceutical companies may benefit from the provided information to design and develop strategies to improve the mental health of suffering individuals.

Tauopathies: Deciphering Disease Mechanisms to Develop Effective Therapies

Tauopathies are neurodegenerative diseases characterized by the pathological accumulation of microtubule-associated protein tau (MAPT) in the form of neurofibrillary tangles and paired helical filaments in neurons and glia, leading to brain cell death. These diseases include frontotemporal dementia (FTD) and Alzheimer's disease (AD) and can be sporadic or inherited when caused by mutations in the MAPT gene. Despite an incredibly high socio-economic burden worldwide, there are still no effective disease-modifying therapies, and few tau-focused experimental drugs have reached clinical trials. One major hindrance for therapeutic development is the knowledge gap in molecular mechanisms of tau-mediated neuronal toxicity and death. For the promise of precision medicine for brain disorders to be fulfilled, it is necessary to integrate known genetic causes of disease, i.e., MAPT mutations, with an understanding of the dysregulated molecular pathways that constitute potential therapeutic targets. Here, the growing understanding of known and proposed mechanisms of disease etiology will be reviewed, together with promising experimental tau-directed therapeutics, such as recently developed tau degraders. Current challenges faced by the fields of tau research and drug discovery will also be addressed.

Tau Protein Aggregation in Alzheimer's Disease: Recent Advances in the Development of Novel Therapeutic Agents

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Major research in Alzheimer’s disease (AD) related to disease-modifying agents is concentrated on pharmacological approaches related to diagnostic markers, neurofibrillary tangles and amyloid plaques. Although most studies focus on anti-amyloid strategies, investigations on tau protein have produced significant advances in the modulation of the pathophysiology of several neurodegenerative diseases. Since the discovery of phenothiazines as tau protein aggregation inhibitors (TAGIs), many additional small molecule inhibitors have been discovered and characterized in biological model systems, which exert their interaction effects by covalent and noncovalent means. In this paper, we summarize the latest advances in the discovery and development of tau aggregation inhibitors using a specialized approach in their chemical classes. The design of new TAGIs and their encouraging use in in vivo and clinical trials support their potential therapeutic use in AD.

Kinetic and thermodynamic study of beta-Boswellic acid interaction with Tau protein investigated by surface plasmon resonance and molecular modeling methods

Introduction: Beta-Boswellic acid (BBA) is a pentacyclic terpene which has been obtained from frankincense and its beneficial effects on neurodegenerative disorders such as Alzheimer’s disease (AD) have been addressed.

Methods: In the present study, thermodynamic and kinetic aspects of BBA interaction with Tau protein as one of the important proteins involved in AD in the absence and presence of glucose has been investigated using surface plasmon resonance (SPR) method. Tau protein was immobilized onto the carboxy methyl dextran chip and its binding interactions with BBA were studied at physiological pH at various temperatures. Glucose interference with these interactions was also investigated.

Results: Results showed that BBA forms a stable complex with Tau (K_D=8.45×10^-7 M) at 298 K. Molecular modeling analysis showed a hydrophobic interaction between BBA and HVPGGG segment of R₂ and R₄ repeated domains of Tau.

Conclusion: The binding affinity increased by temperature enhancement, while it decreased significantly in the presence of glucose. Both association and dissociation of the BBA-Tau complex were accompanied with an entropic activation barrier; however, positive enthalpy and entropy changes revealed that hydrophobic bonding is the main force involved in the interaction.

AGE-RAGE stress: a changing landscape in pathology and treatment of Alzheimer's disease

Numerous hypotheses including amyloid cascade, cholinergic, and oxidative have been proposed for pathogenesis of Alzheimer's disease (AD). The data suggest that advanced glycation end products (AGEs) and its receptor RAGE (receptor for AGE) are involved in the pathogenesis of AD. AGE-RAGE stress, defined as a balance between stressors (AGE, RAGE) and anti-stressors (sRAGE, AGE degraders) in favor of stressors, has been implicated in pathogenesis of diseases. AGE and its interaction with RAGE-mediated increase in the reactive oxygen species (ROS) damage brain because of its increased vulnerability to ROS. AGE and ROS increase the synthesis of amyloid β (Aβ) leading to deposition of Aβ and phosphorylation of tau, culminating in formation of plaques and neurofibrillary tangles. ROS increase the synthesis of Aβ, high-mobility group box 1(HMGB1), and S100 that interacts with RAGE to produce additional ROS resulting in enhancement of AD pathology. Elevation of ROS precedes the Aβ plaques formation. Because of involvement of AGE and RAGE in AD pathology, the treatment should be targeted at lowering AGE levels through reduction in consumption and formation of AGE, and lowering expression of RAGE, blocking of RAGE ligand binding, increasing levels of soluble RAGE (sRAGE), and use of antioxidants. The above treatment aspect of AD is lacking. In conclusion, AGE-RAGE stress initiates, and Aβ, HMGB1, and S100 enhance the progression of AD. Reduction of levels of AGE and RAGE, elevation of sRAGE, and antioxidants would be beneficial therapeutic modalities in the prevention, regression, and slowing of progression of AD.

Anthraquinone Derivative Reduces Tau Oligomer Progression by Inhibiting Cysteine-Cysteine Interaction

Tau protein is a natively unfolded protein whose primary role is to participate in axonal transport closely associated with microtubules. Neurodegenerative disorders including Alzheimer's disease and Tauopathies involved tau protein that is found hyperphosphorylated in vivo; then, tau is detached from microtubules to form toxic aggregates or oligomers, which have a deleterious effect on membranes, triggering an inflammatory response. Considering finding tau inhibitors, we isolated two compounds in the ethyl acetate extract from Xanthoria ectaneoides (Nyl.) Zahlbr; ergosterol peroxide (1) and a new anthraquinone (2). We established the structure through spectroscopic data and biogenic considerations, and we named it "2-hydroxy-3-((8-hydroxy-3-methoxy-6-methylanthraquinonyl)oxy)propanoic acid". This new anthraquinone was evaluated as a tau inhibitor by ThT fluorescence, dot blot assays and total internal reflection fluorescence microscopy. Our results strongly suggest that this anthraquinone remodels soluble oligomers and diminishes β-sheet content. Moreover, through the fluorescence labeling of cysteine inside of the microtubule-binding domain (4R), we showed that this anthraquinone could reduce the oligomers progression by inhibiting cysteine interactions.

Continental and Antarctic Lichens: isolation, identification and molecular modeling of the depside tenuiorin from the Antarctic lichen Umbilicaria antarctica as tau protein inhibitor

Alzheimer´s disease (AD) is the most common form of dementia involving Aβ and tau protein. So far, AD cure remains elusive, but considering that AD progresses throughout tau pathology, which turns tau protein an appropriate target, besides tau is also included in other neurodegenerative disorders named as tauopathies. Here, we have isolated seventeen compounds belonging to six lichens species. Due to scarce of spectroscopic data of the compound 5,7-dihydroxy-6-methylphthalide, we explained their structural elucidation based on NMR data. In this study, we show that only tenuiorin from Umbilicaria antarctica inhibited 50% of tau 4R at 100 µM. Then, we shown that molecular interactions of tenuiorin with the steric zipper model of the hexapeptide ³⁰⁶VQIVYK³¹¹ were studied by docking calculations and the results suggested that tenuiorin forms both hydrogen bonds with lysine and glutamine side chains and forms several hydrophobic interactions with valine and lysine from ³⁰⁶VQIVYK³¹¹ motif.

Targeting Intrinsically Disordered Transcription Factors: Changing the Paradigm

Increased understanding of intrinsically disordered proteins (IDPs) and protein regions has revolutionized our view of the relationship between protein structure and function. Data now support that IDPs can be functional in the absence of a single, fixed, three-dimensional structure. Due to their dynamic morphology, IDPs have the ability to display a range of kinetics and affinity depending on what the system requires, as well as the potential for large-scale association. Although several studies have shed light on the functional properties of IDPs, the class of intrinsically disordered transcription factors (TFs) is still poorly characterized biophysically due to their combination of ordered and disordered sequences. In addition, TF modulation by small molecules has long been considered a difficult or even impossible task, limiting functional probe development. However, with evolving technology, it is becoming possible to characterize TF structure-function relationships in unprecedented detail and explore avenues not available or not considered in the past. Here we provide an introduction to the biophysical properties of intrinsically disordered TFs and we discuss recent computational and experimental efforts toward understanding the role of intrinsically disordered TFs in biology and disease. We describe a series of successful TF targeting strategies that have overcome the perception of the "undruggability" of TFs, providing new leads on drug development methodologies. Lastly, we discuss future challenges and opportunities to enhance our understanding of the structure-function relationship of intrinsically disordered TFs.

Preclinical, phase I, and phase II investigational clinical trials for treatment of progressive supranuclear palsy

INTRODUCTION

Our understanding of the pathological basis of progressive supranuclear palsy (PSP), as the most common atypical parkinsonian syndrome, has greatly increased in recent years and a number of disease-modifying therapies are under evaluation as a result of these advances.

AREAS COVERED

In this review, we discuss disease-modifying therapeutic options which are currently under evaluation or have been evaluated in preclinical or clinical trials based on their targeted pathophysiologic process. The pathophysiologic mechanisms are broadly divided into three main categories: genetic mechanisms, abnormal post-translational modifications of tau protein, and transcellular tau spread.

EXPERT OPINION

Once the best therapeutic approaches are identified, it is likely that some combination of interventions will need to be evaluated, but this will take time. It is critical to treat patients at early stages, and development of the Movement Disorder Society PSP diagnostic criteria is an important step in this direction. In addition, development of biological biomarkers such as tau PET and further refinement of tau ligands may help both diagnose early and measure disease progression. In the meantime, a comprehensive, personalized interdisciplinary approach to this disease is absolutely necessary.