A multi-target directed ligands strategy for the treatment of Alzheimer's disease: Dimethyl fumarate plus Tranilast modified Dithiocarbate as AChE inhibitor and Nrf2 activator

Discovery and biological evaluation of potent 2-trifluoromethyl acrylamide warhead-containing inhibitors of protein disulfide isomerase

Protein disulfide isomerase (PDI) regulates multiple protein functions by catalyzing the oxidation, reduction, and isomerization of disulfide bonds. The enzyme is considered a potential target for treating thrombosis. We previously developed a potent PDI inhibitor, CPD, which contains the propiolamide as a warhead targeting cysteine residue in PDI. To address its issues with undesirable off-target effects and weak metabolic stability, we replaced the propiolamide group with various electrophiles. Among these, compound 2d, which contains 2-trifluoromethyl acrylamide exhibited potent PDI inhibition compared to the reference PACMA31. Further structural optimization of compound 2d led to a novel series of 2-trifluoromethyl acrylamide derivatives. Several of these compounds displayed substantially improved enzyme inhibition. Notably, compound 14d demonstrated the strongest inhibition against PDI, with an IC50 value of 0.48 ± 0.004 μM. Additionally, compound 14d was found to exhibit a reversible binding mode with PDI enzyme. Further biological evaluations show that 14d suppressed platelet aggregation and thrombus formation by attenuating GPIIb/IIIa activation without significantly causing cytotoxicity. Altogether, these findings suggest PDI inhibitors could be a potential strategy for anti-thrombosis.

Curcumin mimics of potential chemoprevention with NQO1 induction properties

Chemoprevention is one of the accessible strategies for preventing, delaying or reversing cancer processing utilizing chemical intervention of carcinogenesis. NAD(P)H quinone oxidoreductase 1 (NQO1) is a xenobiotic metabolizing cytosolic enzyme/protein with important functional properties towards oxidation stress, supporting its ability in detoxification/chemoprotective role. A set of 3,5-diylidene-4-piperidones (as curcumin mimics) bearing alkyl sulfonyl group were synthesized with potential NQO1 induction properties. Compounds 5ab (R = 2-MeOC6H4, R' = Me) and 5ac (R = 2-MeOC6H4, R' = Et) are the most promising agents synthesized (% induction of NQO1 = 51.562, 45.793) relative to that of 4'-bromoflavone (4'-BF, reference standard) at 10 µM. LPS-induced iNOS production in RAW264.7 macrophages of the most promising agents discovered (5ab and 5ac) displayed concentration-dependent with comparable activities to the reference anti-inflammatory drug indomethacin. Molecular modeling studies (including QSAR, molecular docking and molecular dynamics) were accessed supporting the observed biological profiles.

Design, synthesis and biological evaluation of novel pyrazolinone derivatives as multifunctional ligands for the treatment of Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by the depletion of cholinergic neurons and the accumulation of amyloid β (Aβ) plaques. The complexity and multifaceted nature of AD necessitate further exploration of multi-target drugs for its treatment. In this study, a series of novel pyrazolinone-based compounds were designed, synthesized, and evaluated as acetylcholinesterase (AChE) inhibitors and antioxidants. The lead compounds ET11 and ET21 showed strong inhibitory activity against human AChE, with IC50 values of 6.34 and 1.81 nM, respectively. In vitro DPPH and ORACFL assays confirmed the compounds' strong antioxidant capabilities. ET11 exhibited excellent neuroprotective activity in the tBHP-induced SH-SY5Y cell damage model. Benefiting from the pyridopyrazolone moiety, ET11 showed significant Cu2+ chelating ability and effectively inhibited Cu2+-induced Aβ aggregation. In vivo behavioral studies and histopathology analysis preliminarily confirmed the compound's cognitive improvement and neuroprotective effects. Overall, these findings suggested that compound ET11 is expected to play a synergistic role in the treatment of AD, potentially slowing disease progression.

Inflammasomes in neurodegenerative diseases

Inflammasomes represent a crucial component of the innate immune system, which respond to threats by recognizing different molecules. These are known as pathogen-associated molecular patterns (PAMPs) or host-derived damage-associated molecular patterns (DAMPs). In neurodegenerative diseases and neuroinflammation, the accumulation of misfolded proteins, such as beta-amyloid and alpha-synuclein, can lead to inflammasome activation, resulting in the release of interleukin (IL)-1β and IL-18. This activation also induces pyroptosis, the release of inflammatory mediators, and exacerbates neuroinflammation. Increasing evidence suggests that inflammasomes play a pivotal role in neurodegenerative diseases. Therefore, elucidating and investigating the activation and regulation of inflammasomes in these diseases is of paramount importance. This review is primarily focused on evidence indicating that inflammasomes are activated through the canonical pathway in these diseases. Inflammasomes as potential targets for treating neurodegenerative diseases are also discussed.

Discovery of new 4-aminoquinoline derivatives containing an amine or hydroxamic acid terminal as multifunctional agents for the treatment of Alzheimer's disease

Due to the multifactorial nature of Alzheimer's disease (AD), effective multi-targeted directed ligands (MTDLs) are urgently needed for its treatment as single-target drugs currently encounter therapeutic challenges. Two series of new 4-aminoquinoline derivatives containing an amine or hydroxamic acid terminal were designed, synthesized and evaluated for their cholinesterase inhibition, antioxidant and metal-ion chelation properties. Among them, hydroxamic acid-containing compounds 7r and 7f exhibited the best inhibitor activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE), respectively, with the corresponding IC50 values of 0.41 and 1.06 μM, which were superior to those of rivastigmine (IC50 = 5.26, 2.02 μM, respectively). Moreover, compounds 7r and 7f presented excellent ABTS radical scavenging efficiency and selective metal-ion chelation ability such as Cu2+ and Fe2+. Both molecular docking and enzyme kinetic analysis revealed that compound 7r was a mixed-type inhibitor of AChE. Additionally, the ADME prediction indicated that compounds 7r and 7f have suitable pharmacokinetic and drug-like properties. Furthermore, they demonstrated good safety and blood-brain barrier permeability in cytotoxicity assays and in vivo experiments, respectively. These findings strongly suggest that the 4-aminoquinoline derivatives containing a hydroxamic acid terminal have great potential as promising MTDLs for the treatment of AD, opening new avenues for future therapeutic strategies.

Peroxynitrite-Triggered Carbon Monoxide Donor Improves Ischemic Stroke Outcome by Inhibiting Neuronal Apoptosis and Ferroptosis

Cerebral ischemia-reperfusion injury produces excessive reactive oxygen and nitrogen species, including superoxide, nitric oxide, and peroxynitrite (ONOO-). We recently developed a new ONOO--triggered metal-free carbon monoxide donor (PCOD585), exhibiting a notable neuroprotective outcome on the rat middle cerebral artery occlusion model and rendering an exciting intervention opportunity toward ischemia-induced brain injuries. However, its therapeutic mechanism still needs to be addressed. In the pharmacological study, we found PCOD585 inhibited neuronal Bcl2/Bax/caspase-3 apoptosis pathway in the peri-infarcted area of stroke by scavenging ONOO-. ONOO- scavenging further led to decreased Acyl-CoA synthetase long-chain family member 4 and increased glutathione peroxidase 4, to minimize lipoperoxidation. Additionally, the carbon monoxide release upon the ONOO- reaction with PCOD585 further inhibited the neuronal Iron-dependent ferroptosis associated with ischemia-reperfusion. Such a synergistic neuroprotective mechanism of PCOD585 yields as potent a neuroprotective effect as Edaravone. Additionally, PCOD585 penetrates the blood-brain barrier and reduces the degradation of zonula occludens-1 by inhibiting matrix metalloproteinase-9, thereby protecting the integrity of the blood-brain barrier. Our study provides a new perspective for developing multi-functional compounds to treat ischemic stroke.

Therapeutic Options in Alzheimer's Disease: From Classic Acetylcholinesterase Inhibitors to Multi-Target Drugs with Pleiotropic Activity

Alzheimer's disease (AD) is a complex/multifactorial brain disorder involving hundreds of defective genes, epigenetic aberrations, cerebrovascular alterations, and environmental risk factors. The onset of the neurodegenerative process is triggered decades before the first symptoms appear, probably due to a combination of genomic and epigenetic phenomena. Therefore, the primary objective of any effective treatment is to intercept the disease process in its presymptomatic phases. Since the approval of acetylcholinesterase inhibitors (Tacrine, Donepezil, Rivastigmine, Galantamine) and Memantine, between 1993 and 2003, no new drug was approved by the FDA until the advent of immunotherapy with Aducanumab in 2021 and Lecanemab in 2023. Over the past decade, more than 10,000 new compounds with potential action on some pathogenic components of AD have been tested. The limitations of these anti-AD treatments have stimulated the search for multi-target (MT) drugs. In recent years, more than 1000 drugs with potential MT function have been studied in AD models. MT drugs aim to address the complex and multifactorial nature of the disease. This approach has the potential to offer more comprehensive benefits than single-target therapies, which may be limited in their effectiveness due to the intricate pathology of AD. A strategy still unexplored is the combination of epigenetic drugs with MT agents. Another option could be biotechnological products with pleiotropic action, among which nosustrophine-like compounds could represent an attractive, although not definitive, example.

Innovative pathological network-based multitarget approaches for Alzheimer's disease treatment

Alzheimer's disease (AD) is the most prevalent neurodegenerative disease and is a major health threat globally. Its prevalence is forecasted to exponentially increase during the next 30 years due to the global aging population. Currently, approved drugs are merely symptomatic, being ineffective in delaying or blocking the relentless disease advance. Intensive AD research describes this disease as a highly complex multifactorial disease. Disclosure of novel pathological pathways and their interconnections has had a major impact on medicinal chemistry drug development for AD over the last two decades. The complex network of pathological events involved in the onset of the disease has prompted the development of multitarget drugs. These chemical entities combine pharmacological activities toward two or more drug targets of interest. These multitarget-directed ligands are proposed to modify different nodes in the pathological network aiming to delay or even stop disease progression. Here, we review the multitarget drug development strategy for AD during the last decade.

The role of Nrf2 signaling pathways in nerve damage repair

The protein, Nuclear factor-E2-related factor 2 (Nrf2), is a transitory protein that acts as a transcription factor and is involved in the regulation of many cytoprotective genes linked to xenobiotic metabolism and antioxidant responses. Based on the existing clinical and experimental data, it can be inferred that neurodegenerative diseases are characterized by an excessive presence of markers of oxidative stress (OS) and a reduced presence of antioxidant defense systems in both the brain and peripheral tissues. The presence of imbalances in the homeostasis between oxidants and antioxidants has been recognized as a substantial factor in the pathogenesis of neurodegenerative disorders. The dysregulations include several cellular processes such as mitochondrial failure, protein misfolding, and neuroinflammation. These dysregulations all contribute to the disruption of proteostasis in neuronal cells, leading to their eventual mortality. A noteworthy component of Nrf2, as shown by recent research undertaken over the last decade, is to its role in the development of resistance to OS. Nrf2 plays a pivotal role in regulating systems that defend against OS. Extant research offers substantiation for the protective and defensive roles of Nrf2 in the context of neurodegenerative diseases. The purpose of this study is to provide a comprehensive analysis of the influence of Nrf2 on OS and its function in regulating antioxidant defense systems within the realm of neurodegenerative diseases. Furthermore, we evaluate the most recent academic inquiries and empirical evidence about the beneficial and potential role of certain Nrf2 activator compounds within the realm of therapeutic interventions.

A comprehensive review of multi-target directed ligands in the treatment of Alzheimer's disease

Alzheimer's disease (AD) is the most common form of dementia affecting specifically older population. AD is an irreversible neurodegenerative CNS disorder associated with complex pathophysiology. Presently, the USFDA has approved only four drugs viz. Donepezil, Rivastigmine, Memantine, and Galantamine for the treatment of AD. These drugs exhibit their neuroprotective effects either by inhibiting cholinesterase enzyme (ChE) or N-methyl-d-aspartate (NMDA) receptor. However, the conventional therapy "one target, one molecule" has failed to provide promising therapeutic effects due to the multifactorial nature of AD. This triggered the development of a novel strategy called Multi-Target Directed Ligand (MTDL) which involved designing one molecule that acts on multiple targets simultaneously. The present review discusses the detailed pathology involved in AD and the various MTDL design strategies bearing different heterocycles, in vitro and in vivo activities of the compounds, and their corresponding structure-activity relationships. This knowledge will allow us to identify and design more effective MTDLs for the treatment of AD.

Design, synthesis, and biological evaluation of novel tryptanthrin derivatives as selective acetylcholinesterase inhibitors for the treatment of Alzheimer's disease

Two novel series of tryptanthrin (TRYP) derivatives were designed and synthesized as multifunctional agents for the treatment of Alzheimer's disease (AD). Inhibition assay against cholinesterase (ChE) indicated that these derivatives can act as acetylcholinesterase (AChE) inhibitors with selectivity over butyrylcholinesterase (BuChE). Among them, n1 exhibited the most excellent ChE inhibitory potency (AChE, IC50 = 12.17 ± 1.50 nM; BuChE, IC50 = 6.29 ± 0.48 μΜ; selectivity index = 517). Molecular docking studies indicated that compound n1 can interact with amino acid residues in the catalytic active site and peripheral anionic site of AChE and the molecular dynamics (MD) simulation studies demonstrated that the AChE-n1 complex had good stability. N1 also exhibited anti-amyloid-β (Aβ) aggregation (63.48 % ± 1.02 %, 100 μΜ) and anti-neuroinflammation activity (NO, IL-1β, TNF-α; IC50 = 2.13 ± 0.54 μΜ, 2.21 ± 0.37 μΜ, 2.47 ± 0.07 μΜ, respectively), and n1 had neuroprotective and metal-chelating properties. Further studies indicated n1 had proper blood-brain barrier permeability in the Parallel artificial membrane permeation assay. In vivo studies found that n1 effectively improved learning and memory impairment in scopolamine-induced AD mouse models. Nissl staining ofmice hippocampaltissue sections revealed that n1 restored neuronal cells in the hippocampus CA3 and CA1 regions. These findings suggested that n1 can be a promising compound for further development of multifunctional agents for AD treatment.

Recent Advancements in the Treatment of Alzheimer's Disease: A Multitarget-directed Ligand Approach

Alzheimer's disease (AD) is a neurodegenerative disease and one of the leading causes of progressive dementia, affecting 50 million people worldwide. Many pathogenic processes, including amyloid β aggregation, tau hyperphosphorylation, oxidative stress, neuronal death, and deterioration of the function of cholinergic neurons, are associated with its progression. The one-compound-one-target treatment paradigm was unsuccessful in treating AD due to the multifaceted nature of Alzheimer's disease. The recent development of multitarget-directed ligand research has been explored to target the complementary pathways associated with the disease. We aimed to find the key role and progress of MTDLs in treating AD; thus, we searched for the past ten years of literature on "Pub- Med", "ScienceDirect", "ACS" and "Bentham Science" using the keywords neurodegenerative diseases, Alzheimer's disease, and multitarget-directed ligands. The literature was further filtered based on the quality of work and relevance to AD. Thus, this review highlights the current advancement and advantages of multitarget-directed ligands over traditional single-targeted drugs and recent progress in their development to treat AD.

Berberine ameliorates iron levels and ferroptosis in the brain of 3 × Tg-AD mice

BACKGROUND

Berberine (BBR) is a natural alkaloid extracted from the herb Coptis chinensis. This compound has the ability to penetrate the blood-brain barrier (BBB) and exhibit neuroprotective value in the treatment of Alzheimer's disease (AD). AD is a neurodegenerative disease characterized by β-amyloid (Aβ) deposition, hyperphosphorylated tau and other characters. Iron accumulation and ferroptosis were also detected in AD brain, which can result in neuronal damage. However, it is still unclear whether BBR can suppress ferroptosis in AD and alleviate its underlying pathology.

PURPOSE

This study investigated whether BBR may affect ferroptosis and related signaling pathways in triple transgenic AD (3 × Tg-AD) mice.

METHODS

Four-month-old 3 × Tg-AD mice received oral administration of BBR at a dose of 50 mg/kg for 7.5 months. Cognitive function and anxiety levels in mice were assessed using the morris water maze test, open field test, and novel object recognition test. Western blot, immunohistochemistry, and ICP-MS were employed to assess the pathology of AD, brain iron metabolism, and ferroptosis signaling pathways. Transmission electron microscopy was used to detect mitochondrial changes. The synergistic effects of BBR combined with Nrf2 were investigated using molecular docking programs and surface plasmon resonance technology. Co-inmunoprecipitation assay was used to examine the effect of BBR on the binding ability of Nrf2 and Keap1.

RESULTS

The results indicated that chronic treatment of BBR mitigated cognitive disorders in 3 × Tg-AD model mice. Reductions in Aβ plaque, hyperphosphorylated tau protein, neuronal loss, and ferroptosis in the brains of 3 × Tg-AD mice suggested that BBR could alleviate brain injury. In addition, BBR treatment attenuated ferroptosis, as evidenced by decreased levels of iron, MDA, and ROS, while enhancing SOD, GSH, GPX4, and SLC7A11. Consistent with the in vivo assay, BBR inhibited RSL3-induced ferroptosis in N2a-sw cells. BBR increased the expression levels of GPX4, FPN1 and SLC7A11 by regulating Nrf2 transcription levels, thereby inhibiting ferroptosis. Molecular docking programs and surface plasmon resonance technology demonstrated the direct combination of BBR with Nrf2. Co-inmunoprecipitation analysis showed that BBR inhibited the interaction between Keap1 and Nrf2.

CONCLUSION

For the first time, these results showed that BBR could inhibit iron levels and ferroptosis in the brains of 3 × Tg-AD model mice and partially protect against RSL3-induced ferroptosis via the activation of Nrf2 signaling.

Activators of Nrf2 to Counteract Neurodegenerative Diseases

Neurodegenerative diseases are incurable and debilitating conditions that result in progressive degeneration and loss of nerve cells. Oxidative stress has been proposed as one factor that plays a potential role in the pathogenesis of neurodegenerative disorders since neuron cells are particularly vulnerable to oxidative damage. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is strictly related to anti-inflammatory and antioxidative cell response; therefore, its activation and the consequent enhancement of the related cellular pathways have been proposed as a potential therapeutic approach. Several Nrf2 activators with different mechanisms and diverse structures have been reported, but those applied for neurodisorders are still limited. However, in the very last few years, interesting progress has been made, particularly in enhancing the blood-brain barrier penetration, to make Nrf2 activators effective drugs, and in designing Nrf2-based multitarget-directed ligands to affect multiple pathways involved in the pathology of neurodegenerative diseases. The present review gives an overview of the most representative findings in this research area.

Natural Alkaloids as Multi-Target Compounds towards Factors Implicated in Alzheimer's Disease

Alzheimer's disease (AD) is the most common cause of dementia in elderly people; currently, there is no efficient treatment. Considering the increase in life expectancy worldwide AD rates are predicted to increase enormously, and thus the search for new AD drugs is urgently needed. A great amount of experimental and clinical evidence indicated that AD is a complex disorder characterized by widespread neurodegeneration of the CNS, with major involvement of the cholinergic system, causing progressive cognitive decline and dementia. The current treatment, based on the cholinergic hypothesis, is only symptomatic and mainly involves the restoration of acetylcholine (ACh) levels through the inhibition of acetylcholinesterase (AChE). Since the introduction of the Amaryllidaceae alkaloid galanthamine as an antidementia drug in 2001, alkaloids have been one of the most attractive groups for searching for new AD drugs. The present review aims to comprehensively summarize alkaloids of various origins as multi-target compounds for AD. From this point of view, the most promising compounds seem to be the β-carboline alkaloid harmine and several isoquinoline alkaloids since they can simultaneously inhibit several key enzymes of AD's pathophysiology. However, this topic remains open for further research on detailed mechanisms of action and the synthesis of potentially better semi-synthetic analogues.

Novel neuroprotective pyromeconic acid derivatives with concurrent anti-Aβ deposition, anti-inflammatory, and anti-oxidation properties for treatment of Alzheimer's disease

We synthesized a series of novel pyromeconic acid-styrene hybrid compounds and measured their activities in inhibiting Aβ_1-42 self-aggregation and promoting disaggregation, and their anti-inflammatory and antioxidant properties. The most potent compound, compound 30, had IC₅₀ values of 11.15 μM and 6.87 μM for inhibition of fibril aggregation and promotion of fibril disaggregation, respectively. Because of its redox metal chelating property, 30 also inhibited Cu²⁺-induced Aβ_1-42 fibril aggregation and promoted fibril disaggregation with IC₅₀ of 3.69 μM and 3.35 μM, respectively. Molecular docking demonstrated that 30 interacted with key amino acids of Aβ_1-42, and the reliability of the complex was confirmed by molecular dynamics. In addition, 30 displayed excellent antioxidative activity (oxygen radical absorbance capacity = 2.65 Trolox equivalents) and moderate anti-inflammatory activity and neuroprotection in cell culture assays. Compound 30 was safe in acute toxicity test in mice, and it exhibited favorable pharmacokinetic properties, particularly, accumulation in the hippocampus (maximum ratio of hippocampus to plasma = 7.12). Compound 30 alleviated cognitive deficits in scopolamine-induced amnesia mice; this property may have been attributed to reducing neuroinflammation by inhibiting ionized calcium binding adapter molecule 1 and glial fibrillary acidic protein expression and reducing oxidative stress by activating the Nrf2/HO-1 signaling pathway. In view of its many properties, we envision that 30 is a promising lead for the treatment of Alzheimer's disease.

Current Pharmacotherapy and Multi-Target Approaches for Alzheimer's Disease

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by decreased synaptic transmission and cerebral atrophy with appearance of amyloid plaques and neurofibrillary tangles. Cognitive, functional, and behavioral alterations are commonly associated with the disease. Different pathophysiological pathways of AD have been proposed, some of which interact and influence one another. Current treatment for AD mainly involves the use of therapeutic agents to alleviate the symptoms in AD patients. The conventional single-target treatment approaches do not often cause the desired effect in the disease due to its multifactorial origin. Thus, multi-target strategies have since been undertaken, which aim to simultaneously target multiple targets involved in the development of AD. In this review, we provide an overview of the pathogenesis of AD and the current drug therapies for the disease. Additionally, rationales of the multi-target approaches and examples of multi-target drugs with pharmacological actions against AD are also discussed.

Oxidative stress-induced lncRNA CYLD-AS1 promotes RPE inflammation via Nrf2/miR-134-5p/NF-κB signaling pathway

Oxidative stress-induced damage to and dysfunction of retinal pigment epithelium (RPE) cells are important pathogenetic factors of age-related macular degeneration (AMD); however, the underlying molecular mechanism is not fully understood. Long noncoding RNAs (lncRNAs) have important roles in various biological processes. In this study, using an oxidative damage model in RPE cells, we identified a novel oxidation-related lncRNA named CYLD-AS1. We further revealed that the expression of CYLD-AS1 was increased in RPEs during oxidative stress. Depletion of CYLD-AS1 promoted cell proliferation and mitochondrial function and protected RPE cells against hydrogen peroxide (H₂ O₂ )-induced damage. Mechanistically, CYLD-AS1 also regulated the expression of NRF2, which is related to oxidative stress, and NF-κB signaling pathway members, which are related to inflammation. Remarkably, these two signaling pathways were mediated by the CYLD-AS1 interactor miR-134-5p. Moreover, exosomes secreted by CYLD-AS1 knockdown RPE cells had a lower proinflammatory effect than those secreted by control cells. In summary, our study revealed that CYLD-AS1 affects the oxidative stress-related and inflammatory functions of RPE cells by sponging miR-134-5p to mediate NRF2/NF-κB signaling pathway activity, suggesting that targeting CYLD-AS1 could be a promising strategy for the treatment of AMD and related diseases.