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CLR01 treatment reduces tau aggregation in the CA3 region of P301S-tau mice. Brain sections from P301S-tau mice were stained with Gallyas silver-stain. a–c Representative images of the hippocampus (top) and zooming on the CA3 region (bottom) are presented for the mice treated with 0 (a), 0.3 (b), or 1.0 (c) mg/kg per day CLR01 and show black/dark brown cells containing aggregated tau. d The data were quantified as the number of tau-aggregate-containing cells per mm² in the CA3 and are presented as mean ± SD. P values were calculated using a one-way ANOVA with post hoc Tukey test
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Background
Molecular tweezers (MTs) are broad-spectrum inhibitors of abnormal protein aggregation. A lead MT, called CLR01, has been demonstrated to inhibit the aggregation and toxicity of multiple amyloidogenic proteins in vitro and in vivo. Previously , we evaluated the effect of CLR01 in the 3 × Tg mouse model of Alzheimer’s disease, which overe...
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Tau is a microtubule-associated protein that is mainly expressed in central and peripheral nerve systems. Tau binds to tubulin and regulates assembly and stabilization of microtubule, thus playing a critical role in neuron morphology, axon development and navigation. Tau is highly stable under normal conditions; however, there are several factors t...
Citations
... A phase III clinical trial demonstrated no clinical benefit in AD patients (Gauthier et al., 2016). CLR01 reduced tau aggregation (Di et al., 2021), but no clinical trials have been conducted. ...
Progressive supranuclear palsy (PSP) is a neurodegenerative disease, commonly observed as a movement disorder in the group of parkinsonian diseases. The term PSP usually refers to PSP-Richardson’s syndrome (PSP-RS), the most typical clinical presentation. However, the broad concept of progressive supranuclear palsy syndrome (PSP-S) applies to a set of clinical entities that share a pathophysiological origin and some symptoms. According to its clinical predominance, PSP-S is divided into subtypes. PSP-S has clinical similarities with Parkinson's disease, and both pathologies are classified in the group of parkinsonisms, but they do not share pathophysiological traits. By contrast, the pathophysiology of corticobasal syndrome (CBS) depends on tau expression and shares similarities with PSP-S in both pathophysiology and clinical picture. An involvement of the immune system has been proposed as a cause of neurodegeneration. The role of neuroinflammation in PSP-S has been studied by neuroimaging, among other methods. As it is the case in other neurodegenerative pathologies, microglial cells have been attributed a major role in PSP-S. While various studies have explored the detection and use of possible inflammatory biomarkers in PSP-S, no significant advances have been made in this regard. This review is aimed at highlighting the most relevant information on neuroinflammation and peripheral inflammation in the development and progression of PSP-S, to lay the groundwork for further research on the pathophysiology, potential biomarkers, and therapeutic strategies for PSP-S.
... Unfortunately, this strategy did not succeed in slowing down motor symptoms. In contrast, CLR01 inhibiting Tau aggregation was able to ameliorate muscle-strength deterioration and anxiety-and disinhibition-like behavior in an Alzheimer's disease mouse model [220]. To our knowledge, CLR01 has not been tested in other ALS models than SOD1. ...
Amyotrophic lateral sclerosis (ALS) is a rapidly progressive neurodegenerative disorder affecting upper and lower motor neurons, with death resulting mainly from respiratory failure three to five years after symptom onset. As the exact underlying causative pathological pathway is unclear and potentially diverse, finding a suitable therapy to slow down or possibly stop disease progression remains challenging. Varying by country Riluzole, Edaravone, and Sodium phenylbutyrate/Taurursodiol are the only drugs currently approved in ALS treatment for their moderate effect on disease progression. Even though curative treatment options, able to prevent or stop disease progression, are still unknown, recent breakthroughs, especially in the field of targeting genetic disease forms, raise hope for improved care and therapy for ALS patients. In this review, we aim to summarize the current state of ALS therapy, including medication as well as supportive therapy, and discuss the ongoing developments and prospects in the field. Furthermore, we highlight the rationale behind the intense research on biomarkers and genetic testing as a feasible way to improve the classification of ALS patients towards personalized medicine.
... There have been various attempts to alleviate or prevent the progression of tau-related pathology in the PS19 transgenic mouse model of tauopathy. These include immunomodulatory treatments (63)(64)(65)(66), enhanced clearance of senescent glial cells (67), immunization against pathological tau (68), microtubule stabilizers (69)(70)(71), aggregation inhibitors (72,73), and metabolic modulators (74). However, in most of these studies, the treatment was started well before symptom onset, with limited relevance to the clinical situation. ...
Tauopathies are neurodegenerative diseases that are characterized by accumulation of hyperphosphorylated tau protein, higher-order aggregates, and tau filaments. Protein phosphatase 2A (PP2A) is a major tau dephosphorylating phosphatase, and a decrease in its activity has been demonstrated in tauopathies, including Alzheimer's disease. Prolyl oligopeptidase is a serine protease that is associated with neurodegeneration, and its inhibition normalizes PP2A activity without toxicity under pathological conditions. Here, we assessed whether prolyl oligopeptidase inhibition could protect against tau-mediated toxicity in cellular models in vitro and in the PS19 transgenic mouse model of tauopathy carrying the human tau-P301S mutation. We show that inhibition of prolyl oligopeptidase with the inhibitor KYP-2047 reduced tau aggregation in tau-transfected HEK-293 cells and N2A cells as well as in human iPSC-derived neurons carrying either the P301L or tau-A152T mutation. Treatment with KYP-2047 resulted in increased PP2A activity and activation of autophagic flux in HEK-293 cells and N2A cells and in patient-derived iNeurons, as indicated by changes in autophagosome and autophagy receptor markers; this contributed to clearance of insoluble tau. Furthermore, treatment of PS19 transgenic mice for 1 month with KYP-2047 reduced tau burden in the brain and cerebrospinal fluid and slowed cognitive decline according to several behavioral tests. In addition, a reduction in an oxidative stress marker was seen in mouse brains after KYP-2047 treatment. This study suggests that inhibition of prolyl oligopeptidase could help to ameliorate tau-dependent neurodegeneration.
... This is intriguing considering that Aβ and/or phosphorylated tau in BLA alter amygdala function in AD and FTD [54,69], and that neuropsychiatric symptoms are tightly associated with tau in dementia during aging [70,71]. Considering that anxiety is reversed by anti-tau therapeutic treatments [72][73][74], the apparent lack of tau effects on anxiety and fear extinction in APP/Tau mice could be explained by dominating effects of Aβ over tau and/or differences in cell-specific transgene expression, genetic background and/or age of the transgenic lines. ...
Alzheimer’s disease (AD) progresses with memory loss and neuropsychiatric symptoms associated with cell specific vulnerability in memory- and emotion-related neural circuits. Neuropathological and synaptic changes are key factors influencing the clinical progression to dementia, but how they cooperate to cause memory and emotional disturbances is largely unknown. Here, we employed pathological, behavioral, expansion microscopy, electrophysiology and transcriptomic approaches to evaluate the effects of amyloid-β (Aβ) and tau on neuropathological progression, synaptic function, and memory and emotional symptoms in amyloid precursor protein (APP), Tau and double novel APP/Tau transgenic mice expressing the mutant human amyloid precursor protein ( APP Sw,Ind ) and/or microtubule-associated protein tau ( MAPT ) in excitatory neurons. APP/Tau mice of both sexes show spatial learning and memory deficits associated with synaptic tau accumulation and reduced synaptic proteins and neurotransmission in the hippocampus. By contrast, male and female APP/Tau mice exhibit innate anxious behavior and impaired fear memory extinction linked to Aβ pathology and with absence of synaptic tau in the basolateral amygdala (BLA). Intriguingly, APP/Tau mice show NMDA-dependent long-term potentiation (LTP) deficits in the hippocampus but not in the amygdala. Bulk RNA sequencing reveals region-specific but also common transcriptional changes in response to Aβ/tau pathology, including downregulation of synapse transmission and ion channel activity genes. Importantly, we detected 65 orthologs of human AD risk genes identified in GWAS (e.g., APOE , BIN1 , CD33 , CLU , PICALM , PLCG 2, PTK2B , TREM2 , SORL1 , USP6NL ) differentially expressed in the hippocampus and/or BLA of APP/Tau mice, indicating that this APP/Tau model exhibits transcriptional alterations linked to known molecular determinants of AD development. In conclusion, simultaneous development of Aβ and tau neuropathologies in this double APP/Tau transgenic mouse model reproduces synaptic, behavioral, and molecular alterations associated with AD pathophysiology in a region-specific manner. Our findings highlight region-specific pathological effects of Aβ and tau in excitatory neuronal circuits mediating emotional and memory processing, providing evidence that both factors and their molecular cascades should be considered in future AD preventive and therapeutic strategies.
Graphical abstract
Age-dependent vulnerability of memory and emotional neural circuits in response to tau and Aβ pathologies.
... CLR01 has leading effects among molecular tweezers (MTs), which are broad-spectrum protein aggregation inhibitors. In P301S-tau mice, CLR01 was shown to reduce tau aggregation, hyperphosphorylation and oligomerization [180]. No clinical trials have been conducted. ...
Background
Tauopathies are a class of neurodegenerative disorders characterized by neuronal and/or glial tau-positive inclusions.
Main body
Clinically, tauopathies can present with a range of phenotypes that include cognitive/behavioral-disorders, movement disorders, language disorders and non-specific amnestic symptoms in advanced age. Pathologically, tauopathies can be classified based on the predominant tau isoforms that are present in the inclusion bodies (i.e., 3R, 4R or equal 3R:4R ratio). Imaging, cerebrospinal fluid (CSF) and blood-based tau biomarkers have the potential to be used as a routine diagnostic strategy and in the evaluation of patients with tauopathies. As tauopathies are strongly linked neuropathologically and genetically to tau protein abnormalities, there is a growing interest in pursuing of tau-directed therapeutics for the disorders. Here we synthesize emerging lessons on tauopathies from clinical, pathological, genetic, and experimental studies toward a unified concept of these disorders that may accelerate the therapeutics.
Conclusions
Since tauopathies are still untreatable diseases, efforts have been made to depict clinical and pathological characteristics, identify biomarkers, elucidate underlying pathogenesis to achieve early diagnosis and develop disease-modifying therapies.
... In this study, P301S transgenic mice was used which is characterized by development of NFT and tau pathology from 3 months of age and previously showed evident pathology with various staining antibodies against tau protein on similar time plan of our study (Hollerhage et al. 2014;Allen et al. 2002). These mice demonstrated significant motor impairment, anxiety like behavior, reduced exploration when compared to WT (Watt et al. 2020;Sun et al. 2020;Di et al. 2021;Zampar and Wirths 2021) and exhibit behavioral abnormalities that resemble deficits in human tauopathies (Takeuchi et al. 2011).Based on previous studies with this experimental model of tauopathy, tau pathology starts by the third month of age, it then increases till reaching the highest level in 5-6 months, however, by that time animals are totally incapacitated so there is difficulty in behavioral tests assessment (Hollerhage et al. 2014). Hence, experiment of the current study started on 3rd month of age and proceeded for 21 days, where we can find evident pathology when sacrificed yet preserving locomotion of the animals and decreasing mortalities. ...
Background and objective
Tauopathy is a group of neurodegenerative diseases in which the pathogenesis processes are related to tau protein. The imbalances between the activities of kinases and phosphatases of tau protein lead to tau hyperphosphorylation and subsequent neurodegeneration. Numerous studies suggest a strong linkage between type 2 diabetes mellitus (T2D) and neurodegenerative diseases. Therefore, finding a drug with a dual therapeutic activity against T2D and neuroprotective will be a promising idea. Hence, the potential neuroprotective effect of Glimepiride (GPD) against tauopathy was evaluated in the current study.
Methods
P301S mice model was employed for tauopathy and C57BL/6 wild type mice (WT) was used as control. Phosphorylated and acetylated tau protein levels was assessed in cortex and hippocampus by western blot. Effect of GPD on tauopathy related enzymes, neuroinflammation, apoptotic markers were evaluated. Furthermore, the neuroprotective effects against anxiety like behavior and motor impairment was analyzed using Parallel rod floor and Open field tests.
Results
GPD significantly ameliorates motor impairment, anxiety like behavior and neurodegeneration in P301S mice. Phosphorylated tau and acetylated tau were significantly decreased in both cortex and hippocampus of P301S mice via decreasing GSK3β, increasing ratio of phosphorylated-AKT to total-AKT, increasing PP2A and normalization of CDK5 levels. Furthermore, GPD treatment also decreased neuroinflammation and apoptosis by reducing NF-kB, TNF-α and caspase 3 levels.
Conclusion
The current data suggests that GPD exerts a protective effect against tauopathy, behavioural consequences, neurodegeneration, neuroinflammation and apoptosis. GPD is therefore a promising agent for the treatment of neurodegenerative diseases associated with tauopathy.
Graphical abstract
... Several classes of compounds have been tested as tau aggregation inhibitors including small molecules and peptides. [60][61][62][63][64][65] MB was shown to inhibit tau aggregation and reached phase-3 clinical trials, though unfortunately, it failed to achieve a significant therapeutic effect, 64,65 possibly because it targets only tau and not Aβ. 66 In contrast, the molecular tweezer CLR01 was found to inhibit both Aβ and tau aggregation, 67,68 Aβ toxicity, 67,69,70 and tau seeding in cell culture, 68 and both proteins' in vivo pathology. ...
... 66 In contrast, the molecular tweezer CLR01 was found to inhibit both Aβ and tau aggregation, 67,68 Aβ toxicity, 67,69,70 and tau seeding in cell culture, 68 and both proteins' in vivo pathology. 62,70 The tau-specific aggregation inhibitor-peptide, D-TKLIVW, has been reported to inhibit tau aggregation effectively in vitro, 71,72 and has not been tested in vivo. ...
... 68 It also was shown to inhibit seeded intracellular tau aggregation and reduce tau oligomers and seeds in transgenic mouse brains. 62 The lack of an effect of CLR01 on the tau oligomers studied here suggests that they are distinct from those found in vivo, as might be expected. Similarly, we did not find any modulation activity for the all D-peptide, D-TLKIVW, a specific tau aggregation-inhibitor that has been shown to prevent fibrillation of tau fragments, 71 possibly because those fragments are distinct from the full-length tau proteins studied here and/or because the peptide might inhibit only fibril elongation but not the initial oligomerization of tau. ...
Different tauopathies are characterized by the isoform‐specific composition of the aggregates found in the brain and by structurally distinct tau strains. Although tau oligomers have been implicated as important neurotoxic species, little is known about how the primary structures of the six human tau isoforms affect tau oligomerization because the oligomers are metastable and difficult to analyze. To address this knowledge gap, here, we analyzed the initial oligomers formed by the six tau isoforms in the absence of posttranslational modifications or other manipulations using dot blots probed by an oligomer‐specific antibody, native‐PAGE/western blots, photo‐induced cross‐linking of unmodified proteins, mass‐spectrometry, and ion‐mobility spectroscopy. We found that under these conditions, three‐repeat (3R) isoforms are more prone than four‐repeat (4R) isoforms to form oligomers. We also tested whether known inhibitors of tau aggregation affect its oligomerization using three small molecules representing different classes of tau aggregation inhibitors, Methylene Blue (MB), the molecular tweezer CLR01, and the all‐D peptide TLKIVW, for their ability to inhibit or modulate the oligomerization of the six tau isoforms. Unlike their reported inhibitory effect on tau fibrillation, the inhibitors had little or no effect on the initial oligomerization. Our study provides novel insight into the primary–quaternary structure relationship of human tau and suggests that 3R‐tau oligomers may be an important target for future development of compounds targeting pathological tau assemblies.
... Recently, we also found that CLR01 inhibited dose-dependently the prion-like propagation of tau aggregates (tau seeding) in biosensor cells 17 . Moreover, the potential therapeutic effect of CLR01 has been demonstrated in multiple animal models of various proteinopathies including the triple-transgenic mouse model of Alzheimer's disease (AD) 16 , a rat model of AD 18 , a mouse model of tauopathy 19 , zebrafish 12,20 and mouse 15,21 models of Parkinson's disease (PD), a lamprey model of spinal cord injury 22 , and mouse models of transthyretin amyloidosis 14 , desmin-related cardiomyopathy 23 , amyotrophic lateral sclerosis 24 , multiple system atrophy 25 , and the lysosomalstorage disease Sanfilippo syndrome type A 26 . ...
... Tau seeding. Tau seeds were prepared from PS19-mouse hippocampal extracts and added to biosensor cells for measurement of intracellular tau aggregation as described previously 19 . CLR16 was added 24 h after seeding. ...
Lysine-selective molecular tweezers are promising drug candidates against proteinopathies, viral infection, and bacterial biofilm. Despite demonstration of their efficacy in multiple cellular and animal models, important questions regarding their mechanism of action, including cell penetrance and intracellular distribution, have not been answered to date. The main impediment to answering these questions has been the low intrinsic fluorescence of the main compound tested to date, called CLR01. Here, we address these questions using new fluorescently labeled molecular tweezers derivatives. We show that these compounds are internalized in neurons and astrocytes, at least partially through dynamin-dependent endocytosis. In addition, we demonstrate that the molecular tweezers concentrate rapidly in acidic compartments, primarily lysosomes. Accumulation of molecular tweezers in lysosomes may occur both through the endosomal-lysosomal pathway and via the autophagy-lysosome pathway. Moreover, by visualizing colocalization of molecular tweezers, lysosomes, and tau aggregates we show that lysosomes likely are the main site for the intracellular anti-amyloid activity of molecular tweezers. These findings have important implications for the mechanism of action of molecular tweezers in vivo, explaining how administration of low doses of the compounds achieves high effective concentrations where they are needed, and supporting the development of these compounds as drugs for currently cureless proteinopathies. Li et al. design and synthesize fluorescently labeled molecular tweezers to explore their internalization, intracellular localization, and mechanism of endocytosis in brain cells including neurons and astrocytes. The authors find that MTs are internalized in neurons and astrocytes, at least partially through dynamin-dependent endocytosis, and concentrate rapidly in acidic compartments, primarily lysosomes.
... Many host-guest pairs have been used in the manner of pre-assembly, 7,8,9,10,11,12,13,14,15,16 but it is challenging for molecular hosts to capture guests or 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 This article presented here has been accepted for publication in CCS Chemistry and is posted at the guest-conjugated targets in complex biological media. 17,18,19,20,21,22,2324,25,26,27,28,29,30 It is even more challenging to achieve in situ capture in living animals, and there are only very limited successful examples via employing either monovalent 31,32 or multivalent 33,34 systems. In situ capture requires the host-guest pairs to be bioorthogonal, that is, the host-guest pairs are not interfered by biomolecules and salt ions. ...
... Therefore, these macromolecules may work as singular molecular receptors for specific targets that can be used in numerous applications in biology and medicine [114]. Among the different applications, it was reported that a lysine-binding tweezer (CLR01) inhibits the self-assembly of different human amyloidogenic proteins, including Aβ protein, tau, and α-synuclein in vitro and in vivo [115,116]. CLR01 alters the assembly process and promotes the formation of non-amyloidogenic structures that can be efficiently removed by host clearance mechanisms (Figure 2A). In addition, CLR01, and its derivative CLR05, reduced biofilm formation of S. aureus [91]. ...
The choice of an effective therapeutic strategy in the treatment of biofilm-related infections is a significant issue. Amyloids, which have been historically related to human diseases, are now considered to be prevailing structural components of the biofilm matrix in a wide range of bacteria. This assumption creates the potential for an exciting research area, in which functional amyloids are considered to be attractive targets for drug development to dissemble biofilm structures. The present review describes the best-characterized bacterial functional amyloids and focuses on anti-biofilm agents that target intrinsic and facultative amyloids. This study provides a better understanding of the different modes of actions of the anti-amyloid molecules to inhibit biofilm formation. This information can be further exploited to improve the therapeutic strategies to combat biofilm-related infections.
