The potential link between the infections and the development of Alzheimer's disease (AD) has led to speculations about the role of various pathogens in triggering amyloid-β (Aβ) overproduction, possibly leading to AD onset. The globally distributed dog roundworm Toxocara canis was suggested to be a suitable candidate due to neurotropism of the larvae and infection chronicity. This study investigated whether chronic T. canis infection induces AD-like pathology in mice and whether Aβ is toxic to T. canis. BALB/c and APP/PS1 transgenic mice, which overproduce Aβ, were infected with T. canis L3 larvae and monitored for larval burden, Aβ accumulation, and behavioral changes. In vitro tests of recombinant Aβ toxicity against the larvae were also performed. Despite the presence of T. canis larvae in the central nervous system 8 and 16 weeks post-infection, no significant increase in Aβ concentration or AD-related behavioral alterations were observed. Aβ was detected on the surface and within the intestines of T. canis larvae, but in vitro exposure to recombinant Aβ did not affect larval viability or morphology. Our findings suggest that T. canis infection does not trigger AD-like pathology in mice, and Aβ does not act as an antiparasitic agent. This challenges the emerging hypothesis that chronic neurotoxocarosis infections may contribute to AD development.
TITLE: Absence de preuve de pathologie de la maladie d’Alzheimer chez les souris infectées par Toxocara canis. ABSTRACT: Le lien potentiel entre les infections et le développement de la maladie d’Alzheimer (MA) a suscité des spéculations sur le rôle de divers agents pathogènes dans le déclenchement de la surproduction de β-amyloïde (βA), pouvant conduire à l’apparition de la MA. Toxocara canis, un nématode du chien, répandu mondialement, a été suggéré comme un candidat potentiel en raison du neurotropisme de ses larves et de la chronicité de son infection. Cette étude examine si une infection chronique à T. canis induit une pathologie de type MA chez la souris et si la βA est toxique pour T. canis. Des souris transgéniques BALB/c et APP/PS1, qui surproduisent la βA, ont été infectées par des larves L3 de T. canis et la charge larvaire, l’accumulation de βA et les changements comportementaux ont été étudiés. Des tests in vitro de toxicité de la βA recombinante contre les larves ont également été réalisés. Malgré la présence de larves de T. canis dans le système nerveux central 8 et 16 semaines après l’infection, aucune augmentation significative de la concentration de la βA ni d’altération comportementale liée à la MA n’ont été observées. La βA a été détectée à la surface et dans les intestins des larves de T. canis, mais l’exposition in vitro à la βA recombinante n’a pas affecté la viabilité ou la morphologie des larves. Nos résultats suggèrent que l’infection à T. canis ne déclenche pas de pathologie de type MA chez la souris, et que la βA n’agit pas comme agent antiparasitaire. Cela remet en cause l’hypothèse émergente selon laquelle les infections chroniques par neurotoxocarose pourraient contribuer au développement de la MA.
- Klíčová slova
- Alzheimer’s disease, Amyloid-β, Infectious hypothesis, Neurotoxocarosis, Toxocara canis,
- MeSH
- Alzheimerova nemoc * patologie parazitologie etiologie MeSH
- amyloidní beta-protein toxicita metabolismus analýza MeSH
- larva MeSH
- modely nemocí na zvířatech MeSH
- myši inbrední BALB C MeSH
- myši transgenní MeSH
- myši MeSH
- psi MeSH
- střeva parazitologie MeSH
- Toxocara canis * fyziologie růst a vývoj MeSH
- toxokaróza * komplikace patologie parazitologie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- myši MeSH
- psi MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- amyloidní beta-protein MeSH
Amyloid β42 (Aβ42) plays a decisive role in the pathology of Alzheimer's disease. The Aβ42 peptide can aggregate into various supramolecular structures, with oligomers being the most toxic form. However, different Aβ species that cause different effects have been described. Many cell death pathways can be activated in connection with Aβ action, including apoptosis, necroptosis, pyroptosis, oxidative stress, ferroptosis, alterations in mitophagy, autophagy, and endo/lysosomal functions. In this study, we used a model of differentiated SH-SY5Y cells and applied two different Aβ42 preparations for 2 and 4 days. Although we found no difference in the shape and size of Aβ species prepared by two different methods (NaOH or NH4OH for Aβ solubilization), we observed strong differences in their effects. Treatment of cells with NaOH-Aβ42 mainly resulted in damage of mitochondrial function and increased production of reactive oxygen species, whereas application of NH4OH-Aβ42 induced necroptosis and first steps of apoptosis, but also caused an increase in protective Hsp27. Moreover, the two Aβ42 preparations differed in the mechanism of interaction with the cells, with the effect of NaOH-Aβ42 being dependent on monosialotetrahexosylganglioside (GM1) content, whereas the effect of NH4OH-Aβ42 was independent of GM1. This suggests that, although both preparations were similar in size, minor differences in secondary/tertiary structure are likely to strongly influence the resulting processes. Our work reveals, at least in part, one of the possible causes of the inconsistency in the data observed in different studies on Aβ-toxicity pathways.
- Klíčová slova
- Alzheimer´s disease, Amyloid β42, Apoptosis, Cell death, GM1, Necroptosis, Reactive oxygen species,
- MeSH
- Alzheimerova nemoc metabolismus patologie MeSH
- amyloidní beta-protein * metabolismus farmakologie MeSH
- apoptóza * účinky léků MeSH
- buněčná smrt účinky léků MeSH
- lidé MeSH
- mitochondrie metabolismus účinky léků MeSH
- nádorové buněčné linie MeSH
- nekroptóza účinky léků MeSH
- neuroblastom * patologie metabolismus MeSH
- oxidační stres účinky léků MeSH
- peptidové fragmenty * farmakologie MeSH
- reaktivní formy kyslíku * metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- amyloid beta-protein (1-42) MeSH Prohlížeč
- amyloidní beta-protein * MeSH
- peptidové fragmenty * MeSH
- reaktivní formy kyslíku * MeSH
The amyloid cascade hypothesis postulates that extracellular deposits of amyloid β (Aβ) are the primary and initial cause leading to the full development of Alzheimer's disease (AD) with intracellular neurofibrillary tangles; however, the details of this mechanism have not been fully described until now. Our preliminary data, coming from our day-to-day neuropathology practice, show that the primary location of the hyperphosphorylated tau protein is in the vicinity of the cell membrane of dystrophic neurites. This observation inspired us to formulate a hypothesis that presumes an interaction between low-density lipoprotein receptor-related protein 1 (LRP1) and fibrillar aggregates of, particularly, Aβ42 anchored at the periphery of neuritic plaques, making internalization of the LRP1-Aβ42 complex infeasible and, thus, causing membrane dysfunction, leading to the tauopathy characterized by intracellular accumulation and hyperphosphorylation of the tau protein. Understanding AD as a membrane dysfunction tauopathy may draw attention to new treatment approaches not only targeting Aβ42 production but also, perhaps paradoxically, preventing the formation of LRP1-Aβ42.
- Klíčová slova
- Alzheimer’s disease, amyloid β, membrane dysfunction, tauopathy,
- MeSH
- Alzheimerova nemoc * metabolismus patologie etiologie MeSH
- amyloidní beta-protein * metabolismus MeSH
- buněčná membrána metabolismus MeSH
- fosforylace MeSH
- lidé MeSH
- peptidové fragmenty metabolismus MeSH
- protein 1 související s LDL-receptory * metabolismus MeSH
- proteiny tau * metabolismus MeSH
- tauopatie * metabolismus patologie etiologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
- Názvy látek
- amyloidní beta-protein * MeSH
- LRP1 protein, human MeSH Prohlížeč
- peptidové fragmenty MeSH
- protein 1 související s LDL-receptory * MeSH
- proteiny tau * MeSH
Increasing evidence has revealed that cellular senescence drives NDs, including Alzheimer's disease (AD) and Parkinson's disease. Different senescent cell populations secrete senescence-associated secretory phenotypes (SASP), including matrix metalloproteinase-3, interleukin (IL)-1α, IL-6, and IL-8, which can harm adjacent microglia. Moreover, these cells possess high expression levels of senescence hallmarks (p16 and p21) and elevated senescence-associated β-galactosidase activity in in vitro and in vivo ND models. These senescence phenotypes contribute to the deposition of β-amyloid and tau-protein tangles. Selective clearance of senescent cells and SASP regulation by inhibiting p38/mitogen-activated protein kinase and nuclear factor kappa B signaling attenuate β-amyloid load and prevent tau-protein tangle deposition, thereby improving cognitive performance in AD mouse models. In addition, telomere shortening, a cellular senescence biomarker, is associated with increased ND risks. Telomere dysfunction causes cellular senescence, stimulating IL-6, tumor necrosis factor-α, and IL-1β secretions. The forced expression of telomerase activators prevents cellular senescence, yielding considerable neuroprotective effects. This review elucidates the mechanism of cellular senescence in ND pathogenesis, suggesting strategies to eliminate or restore senescent cells to a normal phenotype for treating such diseases.
- Klíčová slova
- Alzheimer’s disease, Amyloid β · tau protein, Cellular senescence, Neurodegenerative diseases, Telomere shortening,
- MeSH
- Alzheimerova nemoc MeSH
- amyloidní beta-protein metabolismus MeSH
- lidé MeSH
- neurodegenerativní nemoci * MeSH
- Parkinsonova nemoc metabolismus MeSH
- sekreční fenotyp asociovaný se senescencí MeSH
- signální transdukce MeSH
- stárnutí buněk * účinky léků MeSH
- zkracování telomer účinky léků MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
- Názvy látek
- amyloidní beta-protein MeSH
Biomarkers are the most significant diagnosis tools tending towards unique approaches and solutions for the prevention and cure of Alzheimer's Disease (AD). The current report provides a clear perception of the concept of various biomarkers and their prominent features through analysis to provide a possible solution for the inhibition of events in AD. Scientists around the world truly believe that crucial hallmarks can serve as critical tools in the early diagnosis, cure, and prevention, as well as the future of medicine. The awareness and understanding of such biomarkers would provide solutions to the puzzled mechanism of this neuronal disorder. Some of the argued biomarkers in the present article are still in an experimental phase as they need to undergo specific clinical trials before they can be considered for treatment.
- Klíčová slova
- Alzheimer’s disease, biomarkers, diagnosis., neurodegenerative diseases, tau protein, β-amyloid peptide,
- MeSH
- Alzheimerova nemoc * farmakoterapie diagnóza metabolismus MeSH
- amyloidní beta-protein metabolismus antagonisté a inhibitory MeSH
- biologické markery * analýza metabolismus MeSH
- lidé MeSH
- proteiny tau metabolismus antagonisté a inhibitory MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
- Názvy látek
- amyloidní beta-protein MeSH
- biologické markery * MeSH
- proteiny tau MeSH
Alzheimer's disease (AD) is a very common neurodegenerative disorder associated with memory loss and a progressive decline in cognitive activity. The two major pathophysiological factors responsible for AD are amyloid plaques (comprising amyloid-beta aggregates) and neurofibrillary tangles (consisting of hyperphosphorylated tau protein). Polyphenols, a class of naturally occurring compounds, are immensely beneficial for the treatment or management of various disorders and illnesses. Naturally occurring sources of polyphenols include plants and plant-based foods, such as fruits, herbs, tea, vegetables, coffee, red wine, and dark chocolate. Polyphenols have unique properties, such as being the major source of anti-oxidants and possessing anti-aging and anti-cancerous properties. Currently, dietary polyphenols have become a potential therapeutic approach for the management of AD, depending on various research findings. Dietary polyphenols can be an effective strategy to tackle multifactorial events that occur with AD. For instance, naturally occurring polyphenols have been reported to exhibit neuroprotection by modulating the Aβ biogenesis pathway in AD. Many nanoformulations have been established to enhance the bioavailability of polyphenols, with nanonization being the most promising. This review comprehensively provides mechanistic insights into the neuroprotective potential of dietary polyphenols in treating AD. It also reviews the usability of dietary polyphenol as nanoformulation for AD treatment.
- Klíčová slova
- Alzheimer’s disease, Dietary polyphenols, Nanoformulation, Neurodegeneration, Neuroinflammation, Neurotherapeutics,
- MeSH
- Alzheimerova nemoc * farmakoterapie dietoterapie metabolismus MeSH
- amyloidní beta-protein metabolismus MeSH
- biologická dostupnost MeSH
- dieta MeSH
- lidé MeSH
- nanočástice chemie MeSH
- neuroprotektivní látky terapeutické užití farmakologie MeSH
- polyfenoly * farmakologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
- Názvy látek
- amyloidní beta-protein MeSH
- neuroprotektivní látky MeSH
- polyfenoly * MeSH
The aberrantly expressed microRNAs (miRNAs) including miR-29c-3p have been reported in the brains of Alzheimer's disease (AD) patients in recent researches. Nevertheless, the functional role and underlying molecular mechanism of miR-29c-3p in AD pathogenesis are still not well elucidated. The purpose of this study was to examine whether miR-29c-3p regulated beta-Ameyloid (Abeta)-induced neurotoxicity by targeting beta-site amyloid precursor protein-cleaving enzyme 1 (BACE1). The expressions of miR 29c 3p and BACE1 mRNA and protein levels in Abeta-treated PC12 cellular AD model were examined by qRT-PCR and western blot analyses. Luciferase reporter assay verified the potential target of miR 29c 3p. Cell viability, apoptosis, and caspase-3 activity in PC12 cells were detected by the MTT assay, flow cytometry, and caspase-3 activity assay, respectively. Our results indicated that miR-29c-3p downregulation and BACE1 upregulation existed in the cellular AD model of PC12 cells. Moreover, miR-29c-3p directly inhibited BACE1 expression. miR-29c-3p overexpression and BACE1 knockdown strengthened Abeta-induced cell apoptosis, and caspase-3 activity in PC12 cells, which was partially eliminated by over-expression of BACE1. Conversely, BACE1 knockdown reversed the miR-29c-3p inhibition- mediated inhibitory effect on Abeta-induced cell toxicity, apoptosis, and caspase-3 activity in PC12 cells. Considering, miR-29c-3p attenuated Abeta-induced neurotoxicity through targeting BACE1 in an cellular AD model of PC12, providing a potential therapeutic target for AD treatment.
- MeSH
- Alzheimerova nemoc * metabolismus MeSH
- amyloidní beta-protein toxicita genetika metabolismus MeSH
- amyloidový prekurzorový protein beta genetika metabolismus MeSH
- aspartátové endopeptidasy genetika metabolismus MeSH
- kaspasa 3 metabolismus MeSH
- krysa rodu Rattus MeSH
- lidé MeSH
- mikro RNA * genetika metabolismus MeSH
- nádorové buněčné linie MeSH
- sekretasy genetika metabolismus MeSH
- zvířata MeSH
- Check Tag
- krysa rodu Rattus MeSH
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- amyloidní beta-protein MeSH
- amyloidový prekurzorový protein beta MeSH
- aspartátové endopeptidasy MeSH
- Bace1 protein, rat MeSH Prohlížeč
- kaspasa 3 MeSH
- mikro RNA * MeSH
- MIRN29 microRNA, rat MeSH Prohlížeč
- sekretasy MeSH
BACKGROUND: Synaptic dysfunction is a major contributor to Alzheimeŕs disease (AD) pathogenesis in addition to the formation of neuritic β-amyloid plaques and neurofibrillary tangles of hyperphosphorylated Tau protein. However, how these features contribute to synaptic dysfunction and axonal loss remains unclear. While years of considerable effort have been devoted to gaining an improved understanding of this devastating disease, the unavailability of patient-derived tissues, considerable genetic heterogeneity, and lack of animal models that faithfully recapitulate human AD have hampered the development of effective treatment options. Ongoing progress in human induced pluripotent stem cell (hiPSC) technology has permitted the derivation of patient- and disease-specific stem cells with unlimited self-renewal capacity. These cells can differentiate into AD-affected cell types, which support studies of disease mechanisms, drug discovery, and the development of cell replacement therapies in traditional and advanced cell culture models. AIM OF REVIEW: To summarize current hiPSC-based AD models, highlighting the associated achievements and challenges with a primary focus on neuron and synapse loss. KEY SCIENTIFIC CONCEPTS OF REVIEW: We aim to identify how hiPSC models can contribute to understanding AD-associated synaptic dysfunction and axonal loss. hiPSC-derived neural cells, astrocytes, and microglia, as well as more sophisticated cellular organoids, may represent reliable models to investigate AD and identify early markers of AD-associated neural degeneration.
- Klíčová slova
- Alzheimer's disease, Astrocytes, Brain organoids, Induced pluripotent stem cells, Microglia, Neural differentiation, Neuronal loss, Neurons,
- MeSH
- Alzheimerova nemoc * genetika metabolismus patologie MeSH
- amyloidní beta-protein genetika metabolismus MeSH
- indukované pluripotentní kmenové buňky * metabolismus patologie MeSH
- lidé MeSH
- neurony metabolismus MeSH
- synapse metabolismus MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
- Názvy látek
- amyloidní beta-protein MeSH
Frentizole is immunosuppressive drug with low acute toxicity and lifespan-prolonging effect. Recently, frentizole´s potential to disrupt toxic amyloid β (Aβ) - Aβ-binding alcohol dehydrogenase (ABAD) interaction in mitochondria in Alzheimer´s brains has been revealed. Another broadly studied drug with anti-aging and immunosuppressive properties is an mTOR inhibitor - rapamycin. Since we do not yet precisely know what is behind the lifespan-prolonging effect of rapamycin and frentizole, whether it is the ability to inhibit the mTOR signaling pathway, reduction in mitochondrial toxicity, immunosuppressive effect, or a combination of all of them, we have decided within our previous work to dock the entire in-house library of almost 240 Aβ-ABAD modulators into the FKBP-rapamycin-binding (FRB) domain of mTOR in order to interlink mTOR-centric and mitochondrial free radical-centric theories of aging and thus to increase the chances of success. Based on the results of the docking study, molecular dynamic simulation and MM-PBSA calculations, we have selected nine frentizole-like compounds (1 - 9). Subsequently, we have determined their real physical-chemical properties (logP, logD, pKa and solubility in water and buffer), cytotoxic/cytostatic, mTOR inhibitory, and in vitro anti-senescence (senolytic and senomorphic) effects. Finally, the three best candidates (4, 8, and 9) have been forwarded for in vivo safety studies to assess their acute toxicity and pharmacokinetic properties. Based on obtained results, only compound 4 demonstrated the best results within in vitro testing, the ability to cross the blood-brain barrier and the lowest acute toxicity (LD50 in male mice 559 mg/kg; LD50 in female mice 575 mg/kg).
- Klíčová slova
- ABAD, Aging, Cellular senescence, Frentizole, MTOR,
- MeSH
- Alzheimerova nemoc * MeSH
- amyloidní beta-protein * metabolismus MeSH
- imunosupresiva MeSH
- léky proti stárnutí MeSH
- myši MeSH
- sirolimus MeSH
- TOR serin-threoninkinasy MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- amyloidní beta-protein * MeSH
- frentizole MeSH Prohlížeč
- imunosupresiva MeSH
- léky proti stárnutí MeSH
- sirolimus MeSH
- TOR serin-threoninkinasy MeSH
The fungal pathogen Candida albicans is linked to chronic brain diseases such as Alzheimer's disease (AD), but the molecular basis of brain anti-Candida immunity remains unknown. We show that C. albicans enters the mouse brain from the blood and induces two neuroimmune sensing mechanisms involving secreted aspartic proteinases (Saps) and candidalysin. Saps disrupt tight junction proteins of the blood-brain barrier (BBB) to permit fungal brain invasion. Saps also hydrolyze amyloid precursor protein (APP) into amyloid β (Aβ)-like peptides that bind to Toll-like receptor 4 (TLR4) and promote fungal killing in vitro while candidalysin engages the integrin CD11b (Mac-1) on microglia. Recognition of Aβ-like peptides and candidalysin promotes fungal clearance from the brain, and disruption of candidalysin recognition through CD11b markedly prolongs C. albicans cerebral mycosis. Thus, C. albicans is cleared from the brain through innate immune mechanisms involving Saps, Aβ, candidalysin, and CD11b.
- Klíčová slova
- Alzheimer’s disease, CD11b, CP: Immunology, CP: Neuroscience, Candida albicans, Toll-like Receptor 4, amyloid beta, blood-brain barrier, candidalysin, cerebral mycosis, microglia, secreted aspartic proteinase,
- MeSH
- Alzheimerova nemoc metabolismus mikrobiologie MeSH
- amyloidní beta-protein metabolismus MeSH
- antigeny CD11b * metabolismus MeSH
- Candida albicans metabolismus MeSH
- fungální proteiny metabolismus MeSH
- mikroglie * metabolismus mikrobiologie MeSH
- mykózy * genetika metabolismus MeSH
- myši MeSH
- toll-like receptor 4 * metabolismus MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
- Názvy látek
- amyloidní beta-protein MeSH
- antigeny CD11b * MeSH
- fungální proteiny MeSH
- toll-like receptor 4 * MeSH