Combination Drug Therapy for the Management of Alzheimer's Disease

Innovative Therapeutic Strategies in Alzheimer's Disease: A Synergistic Approach to Neurodegenerative Disorders

Alzheimer's disease (AD) remains a significant challenge in the field of neurodegenerative disorders, even nearly a century after its discovery, due to the elusive nature of its causes. The development of drugs that target multiple aspects of the disease has emerged as a promising strategy to address the complexities of AD and related conditions. The immune system's role, particularly in AD, has gained considerable interest, with nanobodies representing a new frontier in biomedical research. Advances in targeting antibodies against amyloid-β (Aβ) and using messenger RNA for genetic translation have revolutionized the production of antibodies and drug development, opening new possibilities for treatment. Despite these advancements, conventional therapies for AD, such as Cognex, Exelon, Razadyne, and Aricept, often have limited long-term effectiveness, underscoring the need for innovative solutions. This necessity has led to the incorporation advanced technologies like artificial intelligence and machine learning into the drug discovery process for neurodegenerative diseases. These technologies help identify therapeutic targets and optimize lead compounds, offering a more effective approach to addressing the challenges of AD and similar conditions.

Multifunctional nanoparticle-mediated combining therapy for human diseases

Combining existing drug therapy is essential in developing new therapeutic agents in disease prevention and treatment. In preclinical investigations, combined effect of certain known drugs has been well established in treating extensive human diseases. Attributed to synergistic effects by targeting various disease pathways and advantages, such as reduced administration dose, decreased toxicity, and alleviated drug resistance, combinatorial treatment is now being pursued by delivering therapeutic agents to combat major clinical illnesses, such as cancer, atherosclerosis, pulmonary hypertension, myocarditis, rheumatoid arthritis, inflammatory bowel disease, metabolic disorders and neurodegenerative diseases. Combinatorial therapy involves combining or co-delivering two or more drugs for treating a specific disease. Nanoparticle (NP)-mediated drug delivery systems, i.e., liposomal NPs, polymeric NPs and nanocrystals, are of great interest in combinatorial therapy for a wide range of disorders due to targeted drug delivery, extended drug release, and higher drug stability to avoid rapid clearance at infected areas. This review summarizes various targets of diseases, preclinical or clinically approved drug combinations and the development of multifunctional NPs for combining therapy and emphasizes combinatorial therapeutic strategies based on drug delivery for treating severe clinical diseases. Ultimately, we discuss the challenging of developing NP-codelivery and translation and provide potential approaches to address the limitations. This review offers a comprehensive overview for recent cutting-edge and challenging in developing NP-mediated combination therapy for human diseases.

Single and Multitarget Systems for Drug Delivery and Detection: Up-to-Date Strategies for Brain Disorders

This review summarizes the recent findings on the development of different types of single and multitarget nanoparticles for disease detection and drug delivery to the brain, focusing on promising active principles encapsulated and nanoparticle surface modification and functionalization. Functionalized nanoparticles have emerged as promising tools for the diagnosis and treatment of brain disorders, offering a novel approach to addressing complex neurological challenges. They can act as drug delivery vehicles, transporting one or multiple therapeutic agents across the blood-brain barrier and precisely releasing them at the site of action. In diagnostics, functionalized nanoparticles can serve as highly sensitive contrast agents for imaging techniques such as magnetic resonance imaging and computed tomography scans. By attaching targeting ligands to the nanoparticles, they can selectively accumulate in the affected areas of the brain, enhancing the accuracy of disease detection. This enables early diagnosis and monitoring of conditions like Alzheimer's or Parkinson's diseases. While the field is still evolving, functionalized nanoparticles represent a promising path for advancing our ability to diagnose and treat brain disorders with greater precision, reduced invasiveness, and improved therapeutic outcomes.

Effects of specialized nursing intervention based on quantitative assessment strategy on psychological state and quality of life of patients with senile dementia

OBJECTIVES

To explore the effects of specialized nursing intervention based on quantitative evaluation strategy on the psychological state and quality of life of senile dementia patients.

METHODS

92 senile dementia patients were divided into the control and intervention groups (n = 46 each). Control group was given routine nursing intervention, while intervention group was given specialized nursing intervention based on the quantitative evaluation strategy. Patients' self-care ability, cognitive function, nursing compliance, psychological state, quality of life, and patient satisfaction indexes were measured.

RESULTS

After nursing interventions, the self-care ability (71.73 ± 4.31 vs 63.82 ± 3.97 points) and cognitive functions such as orientation (7.96 ± 1.02 vs 6.53 ± 1.15), memory (2.16 ± 0.39 vs 1.69 ± 0.31), visual-spatial copying (3.78 ± 0.53 vs 3.02 ± 0.65), language skills (7.49 ± 1.26 vs 6.05 ± 1.28), and recall ability (2.13 ± 0.26 vs 1.75 ± 0.28) were significantly improved in the intervention group compared to the control group (P ˂ 0.05). The patient's compliance in the intervention group (95.65%) was prominently higher than the control group (80.43%) (P < 0.05). Notably, patient's psychological state (anxiety and depression) in the intervention group (47.42 ± 3.12 vs 51.39 ± 3.16, 48.52 ± 2.51 vs 52.83 ± 2.49) was better than the control group (P < 0.05). Furthermore, the quality of life was significantly improved in the intervention group (88.11 ± 1.11 vs 71.52 ± 1.24) compared to the control group (P < 0.05). Also, patients' satisfaction with nursing services in the intervention group (97.83%) was higher than the control group (78.26%) (P < 0.05).

CONCLUSIONS

Specialized nursing intervention based on quantitative evaluation strategy can effectively improve patients' self-care ability, and cognitive function, reduce anxiety and depression and enhance the quality of life, which is worthy of clinical promotion and application.

The Major Hypotheses of Alzheimer's Disease: Related Nanotechnology-Based Approaches for Its Diagnosis and Treatment

Alzheimer's disease (AD) is a well-known chronic neurodegenerative disorder that leads to the progressive death of brain cells, resulting in memory loss and the loss of other critical body functions. In March 2019, one of the major pharmaceutical companies and its partners announced that currently, there is no drug to cure AD, and all clinical trials of the new ones have been cancelled, leaving many people without hope. However, despite the clear message and startling reality, the research continued. Finally, in the last two years, the Food and Drug Administration (FDA) approved the first-ever medications to treat Alzheimer's, aducanumab and lecanemab. Despite researchers' support of this decision, there are serious concerns about their effectiveness and safety. The validation of aducanumab by the Centers for Medicare and Medicaid Services is still pending, and lecanemab was authorized without considering data from the phase III trials. Furthermore, numerous reports suggest that patients have died when undergoing extended treatment. While there is evidence that aducanumab and lecanemab may provide some relief to those suffering from AD, their impact remains a topic of ongoing research and debate within the medical community. The fact is that even though there are considerable efforts regarding pharmacological treatment, no definitive cure for AD has been found yet. Nevertheless, it is strongly believed that modern nanotechnology holds promising solutions and effective clinical strategies for the development of diagnostic tools and treatments for AD. This review summarizes the major hallmarks of AD, its etiological mechanisms, and challenges. It explores existing diagnostic and therapeutic methods and the potential of nanotechnology-based approaches for recognizing and monitoring patients at risk of irreversible neuronal degeneration. Overall, it provides a broad overview for those interested in the evolving areas of clinical neuroscience, AD, and related nanotechnology. With further research and development, nanotechnology-based approaches may offer new solutions and hope for millions of people affected by this devastating disease.

Discovery of triazole-bridged aryl adamantane analogs as an intriguing class of multifunctional agents for treatment of Alzheimer's disease

Alzheimer's disease (AD) is a progressive brain disorder associated with slow loss of brain functions leading to memory failure and modest changes in behavior. The multifactorial neuropathological condition is due to a depletion of cholinergic neurons and accumulation of amyloid-beta (Aβ) plaques. Recently, a multi-target-directed ligand (MTDL) strategy has emerged as a robust drug discovery tool to overcome current challenges. In this research work, we aimed to design and develop a library of triazole-bridged aryl adamantane analogs for the treatment of AD. All synthesized analogs were characterized and evaluated through various in vitro and in vivo biological studies. The optimal compounds 32 and 33 exhibited potent inhibitory activities against acetylcholinesterase (AChE) (32 - IC50 = 0.086 μM; 33 - 0.135 μM), and significant Aβ aggregation inhibition (20 μM). N-methyl-d-aspartate (NMDA) receptor (GluN1-1b/GluN2B subunit combination) antagonistic activity of compounds 32 and 33 measured upon heterologous expression in Xenopus laevis oocytes showed IC50 values of 3.00 μM and 2.86 μM, respectively. The compounds possessed good blood-brain barrier permeability in the PAMPA assay and were safe for SH-SY5Y neuroblastoma (10 μM) and HEK-293 cell lines (30 μM). Furthermore, in vivo behavioral studies in rats demonstrated that both compounds improved cognitive and spatial memory impairment at a dose of 10 mg/kg oral administration. Together, our findings suggest triazole-bridged aryl adamantane as a promising new scaffold for the development of anti-Alzheimer's drugs.

Piperidine: A Versatile Heterocyclic Ring for Developing Monoamine Oxidase Inhibitors

The monoamine oxidase enzyme (MAO), which is bound on the membrane of mitochondria, catalyzes the oxidative deamination of endogenous and exogenous monoamines, including monoamine neurotransmitters such as serotonin, adrenaline, and dopamine. These enzymes have been proven to play a significant role in neurodegeneration; thus, they have recently been researched as prospective therapeutic targets for neurodegenerative illness treatment and management. MAO inhibitors have already been marketed as neurodegeneration illness treatments despite their substantial side effects. Hence, researchers are concentrating on developing novel molecules with selective and reversible inhibitory properties. Piperine, which is a phytochemical component present in black pepper, has been established as a potent MAO inhibitor. Piperine encompasses a piperidine nucleus with antibacterial, anti-inflammatory, antihypertensive, anticonvulsant, antimalarial, antiviral, and anticancer properties. The current Review focuses on the structural changes and structure-activity relationships of piperidine derivatives as MAO inhibitors.

Multimodal Migraine Management and the Pursuit of Migraine Freedom: A Narrative Review

Migraine is a neurologic disease with a complex pathophysiology that can be controlled with current treatment options but not cured. Therefore, treatment expectations are highly variable. The concept of migraine freedom was recently introduced and can mean different things, with some, for example, expecting complete freedom from headache and associated symptoms and others accepting the occasional migraine attack if it does not impact functioning. Therefore, migraine management should be optimized so that patients can have the best opportunity to achieve their optimal treatment goals. With migraine freedom as a goal and, given the complex pathophysiology of migraine and the high incidence of comorbidities among individuals with migraine, treatment with a single modality may be insufficient, as it may not achieve migraine freedom in those with more frequent or disabling attacks. In this clinical perspective article, we have identified four key, partially overlapping principles of multimodal migraine treatment: (1) manage common comorbidities; (2) control modifiable risk factors for progression by addressing medication and caffeine overuse; (3) diagnose and treat secondary causes of headache, if present; and (4) individualize acute and preventive treatments to minimize pain, functional disability, and allodynia. There are many barriers to pursuing migraine freedom, and strategies to overcome them should be optimized. Migraine freedom should be an aspirational goal both at the individual attack level and for the disease overall. We believe that a comprehensive and multimodal approach that addresses all barriers people with migraine face could move patients closer to migraine freedom.

In silico identification of novel heterocyclic compounds combats Alzheimer's disease through inhibition of butyrylcholinesterase enzymatic activity

Increasing evidence indicates that heterocyclic molecules possess properties against butyrylcholinesterase (BChE) enzymatic activity, which is a potential therapeutic target for Alzheimer's disease (AD). Thus, this study aimed to further evaluate the relationship between heterocyclic molecules and their biological activities. A dataset of 38 selective and potent heterocyclic compounds (-log[the half‑maximal inhibitory concentration (pIC50)]) values ranging from 8.02 to 10.05) was applied to construct a quantitative structure-activity relationship (QSAR) study, including Bayesian model average (BMA), artificial neural network (ANN), multiple nonlinear regression (MNLR), and multiple linear regression (MLR) models. Four models met statistical acceptance in internal and external validation. The ANN model was superior to other models in predicting the pIC50 of the outcome. The descriptors put into the models were found to be comparable with the target-ligand complex X-ray structures, making these models interpretable. Three selected molecules possess drug-like properties (pIC50 values ranged from 9.19 to 9.54). The docking score between candidates and the BChE receptor (RCSB ID 6EYF) ranged from -8.4 to -9.0 kcal/mol. Remarkably, the pharmacokinetics, biological activities, molecular dynamics, and physicochemical properties of compound 18 (C20H22N4O, pIC50 value = 9.33, oxadiazole derivative group) support its protective effects on AD treatment due to its non-toxic nature, non-carcinogen, cholinergic nature, capability to penetrate the blood-brain barrier, and high gastrointestinal absorption.Communicated by Ramaswamy H. Sarma.

Simultaneous Intranasal Codelivery of Donepezil and Memantine in a Nanocolloidal Carrier: Optimization, Pharmacokinetics, and Pharmacodynamics Studies

This work focuses on developing nanoemulsions using a low-energy emulsification method for the codelivery of donepezil and memantine in one dosage form intended to be administered via the intranasal route for enhanced brain delivery. The nanoemulsion formulation was prepared using a low emulsification technique and characterized using various microscopy and nasal ciliotoxicity studies. The safe nanoemulsion was intended for preclinical pharmacokinetics with brain distribution and pharmacodynamics in a scopolamine-induced murine model. The formulated nanoemulsion was 16 nm in size, with a zeta potential of -7.22 mV, and exhibited a spherical shape. The brain concentration of IN-administered NE for DPZ and MEM was ∼678 and 249 ng/mL after 15 min. This concentration is more than 2 times higher in amount when compared with NE administered via PO, free drug solution administered via IN and PO route both. However, the plasma concentration of IN-administered NE for DPZ and MEM was ∼3 and 28 ng/mL after 15 min. In pharmacodynamic studies, the efficacy of NE administered via the IN route was higher when compared with other groups in neurobehavioral, biochemical estimation, and gene expression studies. The results suggest that the IN route can be explored in the future for the delivery of actives via nanocolloidal carriers in the brain for neurological disorders and can serve as promising alternatives for conventional dosage forms and routes.

Exploring the Potential of Antidiabetic Agents as Therapeutic Approaches for Alzheimer's and Parkinson's Diseases: A Comprehensive Review

Alzheimer's and Parkinson's are two prevalent neurodegenerative disorders with significant societal and healthcare burdens. The search for effective therapeutic approaches to combat these diseases has led to growing interest in exploring the potential of antidiabetic agents. This comprehensive review aims to provide a detailed overview of the current literature on using antidiabetic agents as therapeutic interventions for Alzheimer's and Parkinson's diseases. We discuss the underlying pathological mechanisms of these neurodegenerative diseases, including protein misfolding, inflammation, oxidative stress, and mitochondrial dysfunction. We then delve into the potential mechanisms by which antidiabetic agents may exert neuroprotective effects, including regulation of glucose metabolism and insulin signaling, anti-inflammatory effects, modulation of oxidative stress, and improvement of mitochondrial function and bioenergetics. We highlight in vitro, animal, and clinical studies that support the potential benefits of antidiabetic agents in reducing disease pathology and improving clinical outcomes. However, we also acknowledge these agents' limitations, variability in treatment response, and potential side effects. Furthermore, we explore emerging therapeutic targets and novel approaches, such as glucagon-like peptide-1 receptor (GLP-1R) agonists, insulin sensitizer drugs, neuroinflammation-targeted therapies, and precision medicine approaches. The review concludes by emphasizing the need for further research, including large-scale clinical trials, to validate the efficacy and safety of antidiabetic agents in treating Alzheimer's and Parkinson's disease. The collaboration between researchers, clinicians, and pharmaceutical companies is essential in advancing the field and effectively treating patients affected by these debilitating neurodegenerative disorders.

Development of Novel Herbal Compound Formulations Targeting Neuroinflammation: Network Pharmacology, Molecular Docking, and Experimental Verification

Neuroinflammation plays an important role in the onset and progression of neurodegenerative diseases. The multicomponent and multitarget approach may provide a practical strategy to address the complex pathological mechanisms of neuroinflammation. This study aimed to develop synergistic herbal compound formulas to attenuate neuroinflammation using integrated network pharmacology, molecular docking, and experimental bioassays. Eight phytochemicals with anti-neuroinflammatory potential were selected in the present study. A compound-gene target-signaling pathway network was constructed to illustrate the mechanisms of action of each phytochemical and the interactions among them at the molecular level. Molecular docking was performed to verify the binding affinity of each phytochemical and its key gene targets. An experimental study was conducted to identify synergistic interactions among the eight phytochemicals, and the associated molecular mechanisms were examined by immunoblotting based on the findings from the network pharmacology analysis. Two paired combinations, andrographolide and 6-shogaol (AN-SG) (IC50 = 2.85 μg/mL), and baicalein-6-shogaol (BA-SG) (IC50 = 3.28 μg/mL), were found to synergistically (combination index <1) inhibit the lipopolysaccharides (LPS)-induced nitric oxide production in microglia N11 cells. Network pharmacology analysis suggested that MAPK14, MAPK8, and NOS3 were the top three relevant gene targets for the three phytochemicals, and molecular docking demonstrated strong binding affinities of the phytochemicals to their coded proteins. Immunoblotting suggested that the AN-SG and BA-SG both showed prominent effects in inhibiting inducible nitric oxide synthase (iNOS) (p < 0.01 and p < 0.05, respectively) and MAPKp-p38 (both p < 0.05) compared with those induced by the LPS stimulation only. The AN-SG combination exhibited greater inhibitions of the protein expressions of iNOS (p < 0.05 vs. individual components), which may partly explain the mechanisms of the synergy observed. This study established a practical approach to developing novel herbal-compound formulations using integrated network pharmacology analysis, molecular docking, and experimental bioassays. The study provides a scientific basis and new insight into the two synergistic combinations against neuroinflammation.

Taohong siwu decoction ameliorates cognitive dysfunction through SIRT6/ER stress pathway in Alzheimer's disease

ETHNOPHARMACOLOGICAL RELEVANCE

A growing number of people suffer from Alzheimer's disease (AD), but there is currently no effective treatment yet. Taohong Siwu Decoction (TSD) has been proved to take strong neuropharmacological activity on dementia, but the effect and mechanism of TSD against AD are still elusive.

AIM OF STUDY

To investigate whether TSD could be effective in ameliorating cognitive deficits through SIRT6/ER stress pathway.

MATERIALS AND METHODS

Herein, the APP/PS1 mice, an AD model, and HT-22 cell lines were utilized. Different dosages of TSD (4.25, 8.50 and 17.00 g/kg/d) were administered to the mice for 10 weeks by gavage. Following the behavioral tests, oxidative stress levels were measured using malondialdehyde (MDA) and superoxide dismutase (SOD) kits. Nissl staining and Western blot analyses were used to detect the neuronal function. Then, immunofluorescence and Western blot analysis were applied to evaluate silent information regulator 6 (SIRT6) and ER Stress related protein levels in APP/PS1 mice and HT-22 cells.

RESULTS

Behavioral tests revealed that APP/PS1 mice administered with TSD orally took more time in the target quadrant, crossed more times in the target quadrant, had a higher recognition coefficient, and spent more time in the central region. In addition, TSD could ameliorate oxidative stress and inhibit neuronal apoptosis in APP/PS1 mice. Furthermore, TSD could up-regulate the SIRT6 protein expression and inhibit ER sensing proteins expressions, such as p-PERK and ATF6, in APP/PS1 mice and Aβ_1-42-treated HT22 cells.

CONCLUSION

According to the abovementioned findings, TSD could alleviate cognitive dysfunction in AD by modulating the SIRT6/ER stress pathway.

Ginsenoside Rg1 in neurological diseases: From bench to bedside

Ginseng has been used in China as a superior medicinal material for thousands of years that can nourish the five internal organs, calm the mind and benefit wisdom. Due to its anti-inflammatory, antioxidant and neuroprotective activities, one of the active components of ginseng, ginsenoside Rg1, has been extensively investigated in the remedy of brain disorders, especially dementia and depression. In this review, we summarized the research progress on the action mechanisms of Rg1 ameliorating depression-like behaviors, including inhibition of hyperfunction of hypothalamic-pituitary-adrenal (HPA) axis, regulation of synaptic plasticity and gut flora. Rg1 may alleviate Alzheimer's disease in the early phase, as well as in the middle-late phases through repairing dendrite, axon and microglia- and astrocyte-related inflammations. We also proposed that Rg1 could regulate memory state (the imbalance of working and aversive memory) caused by distinct stimuli. These laboratory studies would further the clinical trials on Rg1. From the prospective of drug development, we discussed the limitations of the present investigations and proposed our ideas to increase permeability and bioavailability of Rg1. Taken together, Rg1 has the potential to treat neuropsychiatric disorders, but a future in-depth investigation of the mechanisms is still required. In addition, drug development will benefit from the clinical trials in one specific neuropsychiatric disorder.

Depletion of gut microbiota resistance in 5×FAD mice enhances the therapeutic effect of mesenchymal stem cell-derived exosomes

Mesenchymal stem cell-derived exosomes (MSCs-exo) can be used for treating Alzheimer's disease (AD) by promoting amyloid-β (Aβ) degradation, modulating immune responses, protecting neurology, promoting axonal growth, and improving cognitive impairment. Increasing evidence suggests that the alteration of gut microbiota is closely related to the occurrence and development of Alzheimer's disease. In this study, we hypothesized that dysbiosis of gut microbiota might limit the therapy of MSCs-exo, and the application of antibiotics would improve the therapy.

METHODS

In this original research study, we used MSCs-exo to treat 5 ×FAD mice and fed them antibiotic cocktails for 1 week to detect cognitive ability and neuropathy. The mice's feces were collected to investigate alterations in the microbiota and metabolites.

RESULTS

The results revealed that the AD gut microbiota eliminated the therapeutic effect of MSCs-exo, whereas antibiotic modulation of disordered gut microbiota and associated metabolites enhanced the therapeutic effect of MSCs-exo.

CONCLUSIONS

These results encourage the research of novel therapeutics to enhance MSCs-exo treatment for AD, which could benefit a broader range of patients with AD.

Brain-neuron targeted nanoparticles for peptide synergy therapy at dual-target of Alzheimer's disease

Since the complex interactions of multiple mechanisms involved in Alzheimer's disease (AD) preclude the monotherapeutic approaches from clinical application, combination therapy has become an attractive strategy for AD treatment. However, to be emphasized, the realization of the edges of combination therapy greatly depends on the reasonable choice of targets and the rational design of combination scheme. Acknowledgedly, amyloid plaques and hyperphosphorylated tau (p-tau) are two main hallmarks in AD with close pathological correlations, implying the hopeful prospect of combined intervention in them for AD treatment. Herein, we developed the nano-combination system, neuron-targeting PEG-PLA nanoparticles (CT-NP) loading two peptide drugs H102, a β-sheet breaker acting on Aβ, and NAP, a microtubule stabilizer acting on p-tau. Compared with free peptide combination, nano-combination system partly aligned the in vivo behaviors of combined peptides and enhanced peptide accumulation in lesion neurons by the guidance of targeting peptide CGN and Tet1, facilitating the therapeutic performance of peptide combination. Further, to maximize the therapeutic potential of nano-combination system, the combination ratio and mode were screened by the quantitative evaluation with combination index and U test, respectively, in vitro and in vivo. The results showed that the separated-loading CT-NP at the combination molar ratio of 2:1 (H102:NAP), CT-NP/H102 + CT-NP/NAP(2:1), generated the strongest synergistic therapeutic effects on Aβ, p-tau and their linkage, and effectually prevented neuroinflammation, reversed the neuronal damage and restored cognitive performance in 3 × Tg-AD transgenic mice. Our studies provide critical data on the effectiveness of nano-combination therapy simultaneously intervening in Aβ and p-tau, confirming the promising application of nano-combination strategy in AD treatment.

Identification of Chromatin Regulatory Factors Related to Immunity and Treatment of Alzheimer's Disease

Alzheimer's disease is one of the common neurodegenerative diseases in the elderly, which mainly manifests as progressively severe cognitive impairment, which seriously affects the quality of life of patients. Chromatin regulators have been shown to be associated with a variety of biological processes, and we mainly explore the relationship between chromatin regulators and Alzheimer's disease. Eight hundred seventy chromatin regulators were collected from previous studies, and data related to Alzheimer's disease patients were downloaded from the GEO database. Finally, we screened chromatin regulators related to Alzheimer's disease immunity, established prediction models, and screened related drugs and miRNAs. We screened 160 differentially expressed CRs, constructed an interaction network, obtained 10 hub genes, successfully constructed a prediction model based on immune-related 5 CRs, and obtained 520 related drugs and 3 related miRNA, which provided an idea for the treatment of Alzheimer's disease. Our study identified 5 chromatin regulators related to Alzheimer's disease, which are expected to be new targets for Alzheimer's disease immunotherapy.

Synthesize heterogeneous biological knowledge via representation learning for Alzheimer's disease drug repurposing

Developing drugs for treating Alzheimer's disease has been extremely challenging and costly due to limited knowledge of underlying mechanisms and therapeutic targets. To address the challenge in AD drug development, we developed a multi-task deep learning pipeline that learns biological interactions and AD risk genes, then utilizes multi-level evidence on drug efficacy to identify repurposable drug candidates. Using the embedding derived from the model, we ranked drug candidates based on evidence from post-treatment transcriptomic patterns, efficacy in preclinical models, population-based treatment effects, and clinical trials. We mechanistically validated the top-ranked candidates in neuronal cells, identifying drug combinations with efficacy in reducing oxidative stress and safety in maintaining neuronal viability and morphology. Our neuronal response experiments confirmed several biologically efficacious drug combinations. This pipeline showed that harmonizing heterogeneous and complementary data/knowledge, including human interactome, transcriptome patterns, experimental efficacy, and real-world patient data shed light on the drug development of complex diseases.

p75NTR enhances cognitive dysfunction in a mouse Alzheimer's disease model by inhibiting microRNA-210-3p-mediated PCYT2 through activation of NF-κB

Alzheimer's disease (AD) is a main cause of dementia and exhibits abnormality in cognitive behaviors. Here, we probed into the role of p75 neurotrophin receptor (p75NTR) in cognitive dysfunction in AD. Primarily, C57BL/6 mouse and neuroblastoma cells were treated by amyloid-beta1-42 (Aβ_1-42), respectively, to establish the in vivo and in vitro models of AD. The downstream genes of p75NTR were predicted by RNA-sequencing and bioinformatics analysis. Then the interaction among p75NTR, nuclear factor kappa B (NF-κB), microRNA-210-3p (miR-210-3p) and phosphoethanolamine cytidylyltransferase 2 (PYCT2) was verified, followed by analysis of their effects on cognitive behaviors and biological characteristics of hippocampal neurons of mouse with AD-like symptoms. p75NTR knockout alleviated cognitive dysfunction in mice with AD-like symptoms and reduced Aβ_1-42-induced hippocampal neuron damage and apoptosis. p75NTR up-regulated miR-210-3p expression by activating NF-κB, thereby limiting PCYT2 expression. PCYT2 silencing in p75NTR^-/- mice promoted neuronal apoptosis and aggravated cognitive dysfunction in AD mouse models. In summary, p75NTR is capable of accelerating cognitive dysfunction in AD by mediating the NF-κB/miR-210-3p/PCYT2 axis.

Stem Cell Therapy for Alzheimer's Disease: A Scoping Review for 2017-2022

Alzheimer's disease (AD) has been a major causal factor for mortality among elders around the world. The treatments for AD, however, are still in the stage of development. Stem cell therapy, compared to drug therapies and many other therapeutic options, has many advantages and is very promising in the future. There are four major types of stem cells used in AD therapy: neural stem cells, mesenchymal stem cells, embryonic stem cells, and induced pluripotent stem cells. All of them have applications in the treatments, either at the (1) cellular level, in an (2) animal model, or at the (3) clinical level. In general, many more types of stem cells were studied on the cellular level and animal model, than the clinical level. We suggest for future studies to increase research on various types of stem cells and include cross-disciplinary research with other diseases. In the future, there could also be improvements in the timeliness of research and individualization for stem cell therapies for AD.

Luteolin and Exercise Combination Therapy Ameliorates Amyloid-β1-42 Oligomers-Induced Cognitive Impairment in AD Mice by Mediating Neuroinflammation and Autophagy

BACKGROUND

Alzheimer's disease (AD) disturbs many patients and family. However, little progress has been made in finding effective treatments. Given AD is a multifactorial disease, luteolin and exercise combination therapy may be more effective than monotherapy.

OBJECTIVE

To explore the therapeutic effect and underlying mechanisms of luteolin and exercise combination therapy in AD treatment.

METHODS

This study utilized a validated mouse model of AD by bilateral injection of amyloid-β (Aβ)1-42 oligomers into the CA1 region of the hippocampus. By combining with animal behavioral test, thioflavin T detection, immunofluorescence and western blot test, the cognitive-enhancing effects of luteolin and exercise combination therapy and the underlying mechanisms were investigated.

RESULTS

Luteolin (100 mg/kg/d) combined with exercise could significantly improve the performance of AD model mice in novel object recognition test, and the improvement was greater than that of monotherapy. Further experiments showed that luteolin and exercise alone or in combination could reverse the increase of Aβ content, the activation of astrocytes and microglia, and the decrease of the level of autophagy in hippocampus and cortex in AD model induced by Aβ1-42 oligomers. While the combination therapy involved more intact hippocampal and cortical areas, with greater degree of changes.

CONCLUSION

Luteolin and exercise combination therapy prevented Aβ1-42 oligomers-induced cognitive impairment, possibly by decreasing neuroinflammation and enhancing autophagy. The luteolin and exercise combination therapy may be a useful therapeutic option for preventing and/or delaying the progression of memory dysfunction of AD.

Molecular mechanisms of Alzheimer's disease: From therapeutic targets to promising drugs

Alzheimer's disease (AD) is a neurodegenerative disease characterized by cognitive impairment so widespread that it interferes with a person's ability to complete daily activities. AD is becoming increasingly common, and it is estimated that the number of patients will reach 152 million by 2050. Current treatment options for AD are symptomatic and have modest benefits. Therefore, considering the human, social, and economic burden of the disease, the development of drugs with the potential to alter disease progression has become a global priority. In this review, the molecular mechanisms involved in the pathology of AD were evaluated as therapeutic targets. The main aim of the review is to focus on new knowledge about mitochondrial dysfunction, oxidative stress, and neuronal transmission in AD, as well as a range of cellular signaling mechanisms and associated treatments. Important molecular interactions leading to AD were described in amyloid cascade and in tau protein function, oxidative stress, mitochondrial dysfunction, cholinergic and glutamatergic neurotransmission, cAMP-regulatory element-binding protein (CREB), the silent mating type information regulation 2 homolog 1 (SIRT-1), neuroinflammation (glial cells), and synaptic alterations. This review summarizes recent experimental and clinical research in AD pathology and analyzes the potential of therapeutic applications based on molecular disease mechanisms.

A Review of the Recent Advances in Alzheimer's Disease Research and the Utilization of Network Biology Approaches for Prioritizing Diagnostics and Therapeutics

Alzheimer's disease (AD) is a polygenic multifactorial neurodegenerative disease that, after decades of research and development, is still without a cure. There are some symptomatic treatments to manage the psychological symptoms but none of these drugs can halt disease progression. Additionally, over the last few years, many anti-AD drugs failed in late stages of clinical trials and many hypotheses surfaced to explain these failures, including the lack of clear understanding of disease pathways and processes. Recently, different epigenetic factors have been implicated in AD pathogenesis; thus, they could serve as promising AD diagnostic biomarkers. Additionally, network biology approaches have been suggested as effective tools to study AD on the systems level and discover multi-target-directed ligands as novel treatments for AD. Herein, we provide a comprehensive review on Alzheimer's disease pathophysiology to provide a better understanding of disease pathogenesis hypotheses and decipher the role of genetic and epigenetic factors in disease development and progression. We also provide an overview of disease biomarkers and drug targets and suggest network biology approaches as new tools for identifying novel biomarkers and drugs. We also posit that the application of machine learning and artificial intelligence to mining Alzheimer's disease multi-omics data will facilitate drug and biomarker discovery efforts and lead to effective individualized anti-Alzheimer treatments.

Novel melatonin-trientine conjugate as potential therapeutic agents for Alzheimer's disease

Researchers continue to explore drug targets to treat the characteristic pathologies of Alzheimer's disease (AD). Some drugs relieve the pathological processes of AD to some extent, but the failed clinical trials indicate that multifunctional agents seem more likely to achieve the therapy goals for this neurodegenerative disease. Herein, a novel compound named melatonin-trientine (TM) has been covalently synthesized with the natural antioxidant compounds melatonin and the metal ion chelator trientine. After toxicological and pharmacokinetic verification, we elucidated the effects of intraperitoneal administration of TM on AD-like pathology in 6-month-old mice that express both the β-amyloid (Aβ) precursor protein and presenilin-1 (APP/PS1). We found that TM significantly decreased Aβ deposition and neuronal degeneration in the brains of the APP/PS1 double transgenic mice. This result may be due to the upregulation of iron regulatory protein-2 (IRP2), insulin degrading enzyme (IDE), and low density lipoprotein receptor related protein 1 (LRP1), which leads to decreases in APP and Aβ levels. Additionally, TM may promote APP non-amyloidogenic processing by activating the melatonin receptor-2 (MT2)-dependent signaling pathways, but not MT1. In addition, TM plays an important role in blocking γ-secretase, tau hyperphosphorylation, neuroinflammation, oxidative stress, and metal ion dyshomeostasis. Our results suggest that TM may effectively maximize the therapeutic efficacy of targeting multiple mechanisms associated with AD pathology.

ER stress and UPR in Alzheimer's disease: mechanisms, pathogenesis, treatments

Alzheimer's disease (AD) is a devastating neurodegenerative disorder characterized by gradual loss of memory and cognitive function, which constitutes a heavy burden on the healthcare system globally. Current therapeutics to interfere with the underlying disease process in AD is still under development. Although many efforts have centered on the toxic forms of Aβ to effectively tackle AD, considering the unsatisfactory results so far it is vital to examine other targets and therapeutic approaches as well. The endoplasmic reticulum (ER) stress refers to the build-up of unfolded or misfolded proteins within the ER, thus, perturbing the ER and cellular homeostasis. Emerging evidence indicates that ER stress contributes to the onset and development of AD. A thorough elucidation of ER stress machinery in AD pathology may help to open up new therapeutic avenues in the management of this devastating condition to relieve the cognitive dementia symptoms. Herein, we aim at deciphering the unique role of ER stress in AD pathogenesis, reviewing key findings, and existing controversy in an attempt to summarize plausible therapeutic interventions in the management of AD pathophysiology.

Aduhelm, a novel anti-amyloid monoclonal antibody, for the treatment of Alzheimer's Disease: A comprehensive review

Alzheimer's disease (AD) is the most common form of dementia affecting millions of individuals, including family members who often take on the role of caregivers. This debilitating disease reportedly consumes 8% of the total United States healthcare expenditure, with medical and nursing outlays accounting for an estimated $290 billion. Cholinesterase inhibitors and N-methyl-D-aspartate receptor antagonists have historically been the most widely used pharmacologic therapies for patients with AD; however, these drugs are not curative. The present investigation describes the epidemiology, pathophysiology, risk factors, presentation, and current treatment of AD followed by the role of the novel monoclonal antibody, Adulhelm, in the treatment of AD. Currently, Adulhelm is the only Food and Drug Administration (FDA) approved drug that acts to slow the progression of this disease. Adulhelm is an anti-amyloid drug that functions by selectively binding amyloid aggregates in both the oligomeric and fibrillar states. Studies show Adulhelm may help to restore neurological function in patients with AD by reducing beta-amyloid plaques and reestablishing neuronal calcium permeability. At present, there is concern the magnitude of this drug's benefit may only be statistically significant, although not clinically significant. Despite skepticism, Adulhelm has proven to significantly decrease amyloid in all cortical brain regions examined. With such high stakes and potential, further research into Adulhelm's clinical efficacy is warranted in the treatment of AD.

New insights into the role and mechanisms of ginsenoside Rg1 in the management of Alzheimer's disease

Alzheimer's disease (AD) is a common neurodegenerative disorder in the elderly characterized by memory loss and cognitive dysfunction. The pathogenesis of AD is complex. One-targeted anti-AD drugs usually fail to delay AD progression. Traditional Chinese medicine records have documented the use of the roots of Panax ginseng (ginseng roots) and its prescriptions to treat dementia. Ginsenoside Rg1, the main ginsenoside component of ginseng roots, exhibits a certain therapeutic effect in the abovementioned diseases, suggesting its potential in the management of AD. Therefore, we combed the pathogenesis of AD and currently used anti-AD drugs, and reviewed the availability, pharmacokinetics, and pharmaceutic studies of ginsenoside Rg1. This review summarizes the therapeutic effects and mechanisms of ginsenoside Rg1 and its deglycosylated derivatives in AD in vivo and in vitro. The main mechanisms include improvement in Aβ and Tau pathologies, regulation of synaptic function and intestinal microflora, and reduction of inflammation, oxidative stress, and apoptosis. The underlying mechanisms mainly involve the regulation of PKC, MAPK, PI3K/Akt, CDK5, GSK-3β, BDNF/TrkB, PKA/CREB, FGF2/Akt, p21WAF1/CIP1, NF-κB, NLRP1, TLR3, and TLR4 signaling pathways. As the effects and underlying mechanisms of ginsenoside Rg1 on AD have not been systematically reviewed, we have provided a comprehensive review and shed light on the future directions in the utilization of ginsenoside Rg1 and ginseng roots as well as the development of anti-AD drugs.

Coagulansin-A improves spatial memory in 5xFAD Tg mice by targeting Nrf-2/NF-κB and Bcl-2 pathway

The present study was designed to investigate the underlying molecular signaling of Coagulansin-A (Coag-A) as a therapeutic agent against Alzheimer's disease (AD). Preliminarily, it exhibited a neuroprotective effect against H₂O₂-induced oxidative stress in HT-22 cells. The in vivo studies were performed by administering Coag-A (0.1, 1, and 10 mg/kg) intraperitoneally to 5xFAD transgenic (Tg) mouse model. Coag-A (10 mg/kg) significantly attenuated the cognitive decline compared to Tg mice group in the shallow water maze (SWM) and Y-maze test paradigms. The anti-aggregation potential of Coag-A was determined by performing Fourier transform-infrared (FT-IR) spectroscopy and differential scanning calorimeter (DSC) analysis in the prefrontal cortex (PFC) and hippocampal (HC) regions of mice brain. The FT-IR spectra demonstrated the inhibition of amyloid beta (Aβ) through a decrease in β-sheet aggregation, along with the inhibition of changes in the lipids, proteins, and phospholipids. The DSC analysis displayed a low-temperature exotherm associated with the reversible process of aggregation of soluble protein fractions prior to denaturation. Furthermore, Coag-A treatment displayed a regular density of granule cells in H&E stained sections, along with a reduced amyloid load and PAS-positive granules in all the regions of interest in mice brain. The real-time polymerase chain reaction (q-PCR), western blot and immunohistochemical (IHC) analysis demonstrated antioxidant, anti-inflammatory, and anti-apoptotic effect of Coag-A by enhancing the expression of nuclear factor erythroid-2-related factor (Nrf-2) and reducing nuclear factor kappa B (NF-κB) and Bax protein expression. In addition, Coag-A significantly increased the antioxidant enzymes and proteins level, along with a reduced pro-inflammatory cytokines production.

A consolidated review on stem cell therapy for treatment and management of Alzheimer's disease

Alzheimer's disease (AD) is one of the most common forms of dementia and affects around 50 million people around the globe. AD is diagnosed mainly through imaging techniques and to date only five drugs are approved for management of AD but no promising treatment is available for AD. So in this review, we are focusing on stem cell therapy for AD. This review will cover all stem cells like mesenchymal stem cells, embryonic stem cells, induced pluripotent stem cells, and neural stem cells. Clinical trials of AD have also been discussed. Finally, limitations of stem cells are discussed with ongoing clinical trials, and in the future stem cell therapy can be used for treatment of AD.

Lignin-carbohydrate complexes suppress SCA3 neurodegeneration via upregulating proteasomal activities

Lignin-carbohydrate complexes (LCCs) represent a group of macromolecules with diverse biological functions such as antioxidative properties. Polyglutamine (polyQ) diseases such as spinocerebellar ataxia type 3 (SCA3) comprise a set of neurodegenerative disorders characterized by the formation of polyQ protein aggregates in patient neurons. LCCs have been reported to prevent such protein aggregation. In this study, we identified a potential mechanism underlying the above anti-protein aggregation activity. We isolated and characterized multiple LCC fractions from bamboo and poplar and found that lignin-rich LCCs (BM-LCC-AcOH and PR-LCC-AcOH) effectively eliminated both monomeric and aggregated mutant ataxin-3 (ATXN3polyQ) proteins in neuronal cells and a Drosophila melanogaster SCA3 disease model. In addition, treatment with BM-LCC-AcOH or PR-LCC-AcOH rescued photoreceptor degeneration in vivo. At the mechanistic level, we demonstrated that BM-LCC-AcOH and PR-LCC-AcOH upregulated proteasomal activity. When proteasomal function was impaired, the ability of the LCCs to suppress ATXN3polyQ aggregation was abolished. Thus, we identified a previously undescribed proteasome-inducing function of LCCs and showed that such activity is indispensable for the beneficial effects of LCCs on SCA3 neurotoxicity.

Citicoline/Coenzyme Q10/Vitamin B3 Fixed Combination Exerts Synergistic Protective Effects on Neuronal Cells Exposed to Oxidative Stress

Background: The present study aimed to investigate the rationale and efficacy of using a citicoline, coenzyme Q10 (CAVAQ10) and vitamin B3 fixed combination in combating inflammation and oxidation in neuronal cells exposed to oxidative stress. Methods: HypoE22 cells and isolated hypothalamic specimens were selected as in vitro models to conduct the experiments. The efficacy of citicoline, CAVAQ10, and vitamin B3, with their fixed combination, were assayed after the exposure of hypothalamic cells to hydrogen peroxide (concentration range 1 nM–10 µM), in order to evaluate the biocompatibility of treatments. The activity of neuroprotective and pro-inflammatory factors, namely, brain-derived neurotrophic factor (BDNF), interleukin-6 (IL-6), and tumor necrosis factor-α (TNFα), involved in the neuronal cell damage in neurodegenerative diseases, were assayed in isolated hypothalamus. Results: Neither citicoline, CAVAQ10, nor vitamin B3 significantly altered hypothalamic cell viability, thus suggesting the biocompatibility of single ingredients and fixed combination in the concentration range considered for the study. In the same condition, citicoline and CAVAQ10 were also effective in reducing the gene expression of monoaminoxidase-B, involved in dopamine degradation. However, only citicoline demonstrated an ability to reduce dopamine levels. Conversely, all compounds were effective in reducing the gene expression of IL-6, and TNFα, and in inducing the gene expression of BDNF, with the co-administration of citicoline/CAVAQ10/vitamin B3 being generally more effective than single ingredients. Conclusions: The present findings support the beneficial and synergistic effects of citicoline, CAVAQ10, and vitamin B3 in fixed combination in reducing inflammation and oxidation, and in stimulating neurotrophin production in neuronal cells.

Copolymer-1 as a potential therapy for mild cognitive impairment

Mild cognitive impairment (MCI) is a prodromal stage of memory impairment that may precede dementia. MCI is classified by the presence or absence of memory impairment into amnestic or non-amnestic MCI, respectively. More than 90% of patients with amnestic MCI who progress towards dementia meet criteria for Alzheimer's disease (AD). A combination of mechanisms promotes MCI, including intracellular neurofibrillary tangle formation, extracellular amyloid deposition, oxidative stress, neuronal loss, synaptodegeneration, cholinergic dysfunction, cerebrovascular disease, and neuroinflammation. However, emerging evidence indicates that neuroinflammation plays an important role in the pathogenesis of cognitive impairment. Unfortunately, there are currently no Food and Drug Administration (FDA)-approved drugs for MCI. Copolymer-1 (Cop-1), also known as glatiramer acetate, is a synthetic polypeptide of four amino acids approved by the FDA for the treatment of relapsing-remitting multiple sclerosis. Cop-1 therapeutic effect is attributed to immunomodulation, promoting a switch from proinflammatory to anti-inflammatory phenotype. In addition to its anti-inflammatory properties, it stimulates brain-derived neurotrophic factor (BDNF) secretion, a neurotrophin involved in neurogenesis and the generation of hippocampal long-term potentials. Moreover, BDNF levels are significantly decreased in patients with cognitive impairment. Therefore, Cop-1 immunization might promote synaptic plasticity and memory consolidation by increasing BDNF production in patients with MCI.

Novel Cyclopentaquinoline and Acridine Analogs as Multifunctional, Potent Drug Candidates in Alzheimer's Disease

A series of new cyclopentaquinoline derivatives with 9-acridinecarboxylic acid and a different alkyl chain length were synthesized, and their ability to inhibit cholinesterases was evaluated. All designed compounds, except derivative 3f, exhibited a selectivity for butyrylcholinesterase (BuChE) with IC₅₀ values ranging from 103 to 539 nM. The 3b derivative revealed the highest inhibitory activity towards BuChE (IC₅₀ = 103.73 nM) and a suitable activity against AChE (IC₅₀ = 272.33 nM). The 3f derivative was the most active compound to AChE (IC₅₀ = 113.34 nM) with satisfactory activity towards BuChE (IC₅₀ = 203.52 nM). The potential hepatotoxic effect was evaluated for both 3b and 3f compounds. The 3b and 3f potential antioxidant activity was measured using the ORAC-FL method. The 3b and 3f derivatives revealed a significantly higher antioxidant potency, respectively 35 and 25 higher than tacrine. Theoretical, physicochemical, and pharmacokinetic properties were calculated using ACD Labs Percepta software. Molecular modeling and kinetic study were used to reveal the mechanism of cholinesterase inhibition in the most potent compounds: 3b and 3f.

Design, Synthesis and Biological Evaluation of New 3,4-Dihydro-2(1H)-Quinolinone-Dithiocarbamate Derivatives as Multifunctional Agents for the Treatment of Alzheimer’s Disease

Background

Alzheimer’s disease (AD) belongs to neurodegenerative disease, and the increasing number of AD patients has placed a heavy burden on society, which needs to be addressed urgently. ChEs/MAOs dual-target inhibitor has potential to treat AD according to reports.

Purpose

To obtain effective multi-targeted agents for the treatment of AD, a novel series of hybrid compounds were designed and synthesized by fusing the pharmacophoric features of 3,4-dihydro-2 (1H)-quinolinone and dithiocarbamate.

Methods

All compounds were evaluated for their inhibitory abilities of ChEs and MAOs. Then, further biological activities of the most promising candidate 3e were determined, including the ability to cross the blood-brain barrier (BBB), kinetics and molecular model analysis, cytotoxicity in vitro and acute toxicity studies in vivo.

Results

Most compounds showed potent and clear inhibition to AChE and MAOs. Among them, compound 3e was considered to be the most effective and balanced inhibitor to both AChE and MAOs (IC₅₀=0.28 µM to eeAChE; IC₅₀=0.34 µM to hAChE; IC₅₀=2.81 µM to hMAO-B; IC₅₀=0.91 µM to hMAO-A). In addition, 3e showed mixed inhibition of hAChE and competitive inhibition of hMAO-B in the enzyme kinetic studies. Further studies indicated that 3e could penetrate the BBB and showed no toxicity on PC12 cells and HT-22 cells when the concentration of 3e was lower than 12.5 µM. More importantly, 3e lacked acute toxicity in mice even at high dose (2500 mg/kg, P.O.).

Conclusion

This work indicated that compound 3e with a six-carbon atom linker and a piperidine moiety at terminal position was a promising candidate and was worthy of further study.

Role of melatonin in Alzheimer's disease: From preclinical studies to novel melatonin-based therapies

Melatonin and novel melatonin-based therapies such as melatonin-containing hybrid molecules, melatonin analogues, and melatonin derivatives have been investigated as potential therapeutics against Alzheimer's disease (AD) pathogenesis. In this review, we examine the developmental trends of melatonin therapies for AD from 1997 to 2021. We then highlight the neuroprotective mechanisms of melatonin therapy derived from preclinical studies. These mechanisms include the alleviation of amyloid-related burden, neurofibrillary tangle accumulation, oxidative stress, neuroinflammation, apoptosis, mitochondrial dysfunction, and impaired neuroplasticity and neurotransmission. We further illustrate the beneficial effects of melatonin on behavior in animal models of AD. Next, we discuss the clinical effects of melatonin on sleep, cognition, behavior, psychiatric symptoms, electroencephalography findings, and molecular biomarkers in patients with mild cognitive impairment and AD. We then explore the effectiveness of novel melatonin-based therapies. Lastly, we discuss the limitations of current melatonin therapies for AD and suggest two emerging research themes for future study.

A Synergistic Combination of DHA, Luteolin, and Urolithin A Against Alzheimer’s Disease

Alzheimer’s disease (AD) is a devastating neurodegenerative disorder and the most common form of dementia worldwide. The classical AD brain is characterized by extracellular deposition of amyloid-β (Aβ) protein aggregates as senile plaques and intracellular neurofibrillary tangles (NFTs), composed of hyper-phosphorylated forms of the microtubule-associated protein Tau. There has been limited success in clinical trials for some proposed therapies for AD, so attention has been drawn toward using alternative approaches, including prevention strategies. As a result, nutraceuticals have become attractive compounds for their potential neuroprotective capabilities. The objective of the present study was to derive a synergistic nutraceutical combination in vitro that may act as a potential preventative therapy for AD. The compounds of interest were docosahexaenoic acid (DHA), luteolin (LUT), and urolithin A (UA). The cell viability and cytotoxicity assays MTS and LDH were used to evaluate the compounds individually and in two-compound combinations, for their ability to inhibit Aβ1–42-induced toxicity in human neuroblastoma BE(2)-M17 cells. The LDH-derived% protection values were used in the program CompuSyn v.1.0 to calculate the combination index (CI) of the two-compound combinations. The software-predicted potentially synergistic (CI &lt; 1) two-compound combinations were validated using CellTiter Glo assay. Finally, a three-compound combination was predicted (D5L5U5) and shown to be the most effective at inhibiting Aβ1–42-induced toxicity. The synergistic combination, D5L5U5 warrants further research for its mechanism of action; however, it can serve as a basis to develop an advanced functional food for the prevention or co-treatment of AD.

Multi-Targets: An Unconventional Drug Development Strategy for Alzheimer’s Disease

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder that eventually leads to dementia and death of the patient. Despite the enormous amounts of resources and efforts for AD drug development during the last three decades, no effective treatments have been developed that can slow or halt the progression of the disease. Currently available drugs for treating AD can only improve clinical symptoms temporarily with moderate efficacies. In recent years, the scientific community has realized these challenges and reconsidered the future directions of AD drug development. The most significant recent changes in AD drug development strategy include shifting from amyloid-based targets to other targets, such as tau, and efforts toward better designs for clinical trials. However, most AD drug development is still focused on a single mechanism or target, which is the conventional strategy for drug development. Although multifactorial mechanisms and, on this basis, multi-target strategies have been proposed in recent years, this approach has not been widely recognized and accepted by the mainstream of AD drug development. Here, we emphasize the multifactorial mechanisms of AD and discuss the urgent need for a paradigm shift in AD drug development from a single target to multiple targets, either with the multi-target–directed ligands approach or the combination therapy approach. We hope this article will increase the recognition of the multifactorial nature of AD and promote this paradigm shift. We believe that such a shift will facilitate successful development of effective AD therapies.

Therapeutic promise of carotenoids as antioxidants and anti-inflammatory agents in neurodegenerative disorders

Neurodegenerative disorders (NDs) including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, Huntington's disease, and multiple sclerosis have various disease-specific causal factors and pathological features. A very common characteristic of NDs is oxidative stress (OS), which takes place due to the elevated generation of reactive oxygen species during the progression of NDs. Furthermore, the pathological condition of NDs including an increased level of protein aggregates can further lead to chronic inflammation because of the microglial activation. Carotenoids (CTs) are naturally occurring pigments that play a significant role in averting brain disorders. More than 750 CTs are present in nature, and they are widely available in plants, microorganisms, and animals. CTs are accountable for the red, yellow, and orange pigments in several animals and plants, and these colors usually indicate various types of CTs. CTs exert various bioactive properties because of its characteristic structure, including anti-inflammatory and antioxidant properties. Due to the protective properties of CTs, levels of CTs in the human body have been markedly linked with the prevention and treatment of multiple diseases including NDs. In this review, we have summarized the relationship between OS, neuroinflammation, and NDs. In addition, we have also particularly focused on the antioxidants and anti-inflammatory properties of CTs in the management of NDs.

Aducanumab, a Novel Anti-Amyloid Monoclonal Antibody, for the Treatment of Alzheimer's Disease: A Comprehensive Review

Alzheimer's disease (AD) is the most common form of dementia affecting millions of individuals, including family members who often take on the role as caregiver. This debilitating disease reportedly consumes 8% of the total United States healthcare expenditure, with medical and nursing outlays accounting for an estimated $290 billion. Cholinesterase inhibitors and N-methyl-D-aspartate receptor antagonists have historically been the most widely used pharmacologic therapies for patients with AD, however, these drugs are not curative. This review discusses the epidemiology, pathophysiology, risk factors, presentation, and current treatment of AD followed by the role of the novel monoclonal antibody, aducanumab, in treatment of AD. Currently aducanumab is the only Food and Drug Administration (FDA) approved drug that acts to slow progression of this disease. Aducanumab is an anti-amyloid drug which functions by selectively binding amyloid aggregates in both the oligomeric and fibrillar states. Studies show aducanumab may help to restore neurological function in patients with AD by reducing beta-amyloid plaques and reestablishing neuronal calcium permeability. However, there is concern the magnitude of this drug's benefit may only be statistically significant and not clinically significant. Despite this skepticism, aducanumab has proven to significantly decrease amyloid in all cortical brain regions examined. In summary, aducanumab has provided hope for those working toward the goal of providing patients a safe and viable treatment option in the management of AD.

Neuroinflammation: A Potential Risk for Dementia

Dementia is a neurodegenerative condition that is considered a major factor contributing to cognitive decline that reduces independent function. Pathophysiological pathways are not well defined for neurodegenerative diseases such as dementia; however, published evidence has shown the role of numerous inflammatory processes in the brain contributing toward their pathology. Microglia of the central nervous system (CNS) are the principal components of the brain’s immune defence system and can detect harmful or external pathogens. When stimulated, the cells trigger neuroinflammatory responses by releasing proinflammatory chemokines, cytokines, reactive oxygen species, and nitrogen species in order to preserve the cell’s microenvironment. These proinflammatory markers include cytokines such as IL-1, IL-6, and TNFα chemokines such as CCR3 and CCL2 and CCR5. Microglial cells may produce a prolonged inflammatory response that, in some circumstances, is indicated in the promotion of neurodegenerative diseases. The present review is focused on the involvement of microglial cell activation throughout neurodegenerative conditions and the link between neuroinflammatory processes and dementia.

In Silico Design of Dual-Binding Site Anti-Cholinesterase Phytochemical Heterodimers as Treatment Options for Alzheimer’s Disease

The number of patients with neurodegenerative diseases, particularly Alzheimer’s disease (AD), continues to grow yearly. Cholinesterase inhibitors (ChEIs) represent the first-line symptomatic drug treatment for mild-to-moderate AD; however, there is an unmet need to produce ChEIs with improved efficacy and reduced side effects. Herein, phytochemicals with reported anti-acetylcholinesterase (AChE) activity were ranked in silico for their anti-AChE potential. Ligands with a similar or higher binding affinity to AChE than galantamine were then selected for the design of novel dual-binding site heterodimeric drugs. In silico molecular docking of heterodimers with the target enzymes, AChE and butyrylcholinesterase (BuChE), were performed, and anti-cholinesterase binding affinities were compared with donepezil. Drug-likeliness properties and toxicity of the heterodimers were assessed using the SwissADME and ProTox-II webservers. Nine phytochemicals displayed similar or higher binding affinities to AChE than galantamine: sanguinarine > huperzine A > chelerythrine > yohimbine > berberine > berberastine > naringenin > akuammicine > carvone. Eleven heterodimeric ligands were designed with phytochemicals separated by four- or five-carbon alkyl-linkers. All heterodimers were theoretically potent AChE and BuChE dual-binding site inhibitors, with the highest affinity achieved with huperzine-4C-naringenin, which displayed 34% and 26% improved affinity to AChE and BuChE, respectively, then the potent ChEI drug, donepezil. Computational pharmacokinetic and pharmacodynamic screening suggested that phytochemical heterodimers would display useful gastrointestinal absorption and with relatively low predicted toxicity. Collectively, the present study suggests that phytochemicals could be garnered for the provision of novel ChEIs with enhanced drug efficacy and low toxicity.

Computational Approaches for Supporting Combination Therapy in the Post-Aducanumab Era in Alzheimer’s Disease

With the approval of aducanumab on the “Accelerated Approval Pathway” and the recognition of amyloid load as a surrogate marker, new successful therapeutic approaches will be driven by combination therapy as was the case in oncology after the launch of immune checkpoint inhibitors. However, the sheer number of therapeutic combinations substantially complicates the search for optimal combinations. Data-driven approaches based on large databases or electronic health records can identify optimal combinations and often using artificial intelligence or machine learning to crunch through many possible combinations but are limited to the pharmacology of existing marketed drugs and are highly dependent upon the quality of the training sets. Knowledge-driven in silico modeling approaches use multi-scale biophysically realistic models of neuroanatomy, physiology, and pathology and can be personalized with individual patient comedications, disease state, and genotypes to create ‘virtual twin patients’. Such models simulate effects on action potential dynamics of anatomically informed neuronal circuits driving functional clinical readouts. Informed by data-driven approaches this knowledge-driven modeling could systematically and quantitatively simulate all possible target combinations for a maximal synergistic effect on a clinically relevant functional outcome. This approach seamlessly integrates pharmacokinetic modeling of different therapeutic modalities. A crucial requirement to constrain the parameters is the access to preferably anonymized individual patient data from completed clinical trials with various selective compounds. We believe that the combination of data- and knowledge driven modeling could be a game changer to find a cure for this devastating disease that affects the most complex organ of the universe.

The Potential Effect of Insulin on AChE and Its Interactions with Rivastigmine In Vitro

There is no definite cure for Alzheimer’s disease (AD) due to its multifactorial origin. Drugs that inhibit acetylcholinesterase (AChE), such as rivastigmine, are promising symptomatic treatments for AD. Emerging evidence suggests that insulin therapy can hinder several aspects of AD pathology. Insulin has been shown to modify the activity of AChE, but it is still unknown how insulin and AChE interact. Combination therapy, which targets several features of the disease based on existing medications, can provide a worthy therapy option for AD management. However, to date, no studies have examined the potential interaction of insulin with AChE and/or rivastigmine in vitro. In the present study, we employed the Response Surface Methodology (RSM) as an in vitro assessment to investigate the effect of insulin on both AChE activity and rivastigmine inhibitory action using a common spectrophotometric assay for cholinesterase activity, Ellman’s method. Our results showed that insulin, even at high concentrations, has an insignificant effect on both the activity of AChE and rivastigmine’s inhibitory action. The variance of our data is near zero, which means that the dispersion is negligible. However, to improve our understanding of the possible interaction of insulin and rivastigmine, or its target AChE, more in silico modelling and in vivo studies are needed.

Novel Multitarget Hydroxamic Acids with a Natural Origin CAP Group against Alzheimer's Disease: Synthesis, Docking and Biological Evaluation

Hydroxamic acids are one of the most promising and actively studied classes of chemical compounds in medicinal chemistry. In this study, we describe the directed synthesis and effects of HDAC6 inhibitors. Fragments of adamantane and natural terpenes camphane and fenchane, combined with linkers of various nature with an amide group, were used as the CAP groups. Accordingly, 11 original target compounds were developed, synthesized, and exposed to in vitro and in vivo biological evaluations, including in silico methods. In silico studies showed that all synthesized compounds were drug-like and could penetrate through the blood-brain barrier. According to the in vitro testing, hydroxamic acids 15 and 25, which effectively inhibited HDAC6 and exhibited anti-aggregation properties against β-amyloid peptides, were chosen as the most promising substances to study their neuroprotective activities in vivo. All in vivo studies were performed using 5xFAD transgenic mice simulating Alzheimer's disease. In these animals, the Novel Object Recognition and Morris Water Maze Test showed that the formation of hippocampus-dependent long-term episodic and spatial memory was deteriorated. Hydroxamic acid 15 restored normal memory functions to the level observed in control wild-type animals. Notably, this effect was precisely associated with the ability to restore lost cognitive functions, but not with the effect on motor and exploratory activities or on the level of anxiety in animals. Conclusively, hydroxamic acid 15 containing an adamantane fragment linked by an amide bond to a hydrocarbon linker is a possible potential multitarget agent against Alzheimer's disease.

Association of peripheral blood DNA methylation level with Alzheimer's disease progression

Background

Identifying biomarkers associated with Alzheimer’s disease (AD) progression may enable patient enrichment and improve clinical trial designs. Epigenome-wide association studies have revealed correlations between DNA methylation at cytosine-phosphate-guanine (CpG) sites and AD pathology and diagnosis. Here, we report relationships between peripheral blood DNA methylation profiles measured using Infinium® MethylationEPIC BeadChip and AD progression in participants from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) cohort.

Results

The rate of cognitive decline from initial DNA sampling visit to subsequent visits was estimated by the slopes of the modified Preclinical Alzheimer Cognitive Composite (mPACC; mPACC_digit and mPACC_trailsB) and Clinical Dementia Rating Scale Sum of Boxes (CDR-SB) plots using robust linear regression in cognitively normal (CN) participants and patients with mild cognitive impairment (MCI), respectively. In addition, diagnosis conversion status was assessed using a dichotomized endpoint. Two CpG sites were significantly associated with the slope of mPACC in CN participants (P < 5.79 × 10⁻⁸ [Bonferroni correction threshold]); cg00386386 was associated with the slope of mPACC_digit, and cg09422696 annotated to RP11-661A12.5 was associated with the slope of CDR-SB. No significant CpG sites associated with diagnosis conversion status were identified. Genes involved in cognition and learning were enriched. A total of 19, 13, and 5 differentially methylated regions (DMRs) associated with the slopes of mPACC_trailsB, mPACC_digit, and CDR-SB, respectively, were identified by both comb-p and DMRcate algorithms; these included DMRs annotated to HOXA4. Furthermore, 5 and 19 DMRs were associated with conversion status in CN and MCI participants, respectively. The most significant DMR was annotated to the AD-associated gene PM20D1 (chr1: 205,818,956 to 205,820,014 [13 probes], Sidak-corrected P = 7.74 × 10⁻²⁴), which was associated with both the slope of CDR-SB and the MCI conversion status.

Conclusion

Candidate CpG sites and regions in peripheral blood were identified as associated with the rate of cognitive decline in participants in the ADNI cohort. While we did not identify a single CpG site with sufficient clinical utility to be used by itself due to the observed effect size, a biosignature composed of DNA methylation changes may have utility as a prognostic biomarker for AD progression.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13148-021-01179-2.