The neurotoxicity of phosphorylated tau protein (P-tau) and mitochondrial dysfunction play a significant role in the pathophysiology of Alzheimer's disease (AD). In vitro studies of the effects of P-tau oligomers on mitochondrial bioenergetics and reactive oxygen species production will allow us to evaluate the direct influence of P-tau on mitochondrial function. We measured the in vitro effect of P-tau oligomers on oxygen consumption and hydrogen peroxide production in isolated brain mitochondria. An appropriate combination of specific substrates and inhibitors of the phosphorylation pathway enabled the measurement and functional analysis of the effect of P-tau on mitochondrial respiration in defined coupling control states achieved in complex I-, II-, and I&II-linked electron transfer pathways. At submicromolar P-tau concentrations, we found no significant effect of P-tau on either mitochondrial respiration or hydrogen peroxide production in different respiratory states. The titration of P-tau showed a nonsignificant dose-dependent decrease in hydrogen peroxide production for complex I- and I&II-linked pathways. An insignificant in vitro effect of P-tau oligomers on both mitochondrial respiration and hydrogen peroxide production indicates that P-tau-induced mitochondrial dysfunction in AD is not due to direct effects of P-tau on the efficiency of the electron transport chain and on the production of reactive oxygen species.
- MeSH
- buněčné dýchání MeSH
- fosforylace MeSH
- krysa rodu rattus MeSH
- lidé MeSH
- mitochondrie * metabolismus MeSH
- mozek metabolismus MeSH
- peroxid vodíku * metabolismus MeSH
- proteiny tau * metabolismus MeSH
- reaktivní formy kyslíku metabolismus MeSH
- spotřeba kyslíku MeSH
- transport elektronů MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The strategy for the development of new drugs for Alzheimer's disease (AD) recognizes that an effective therapy requires early therapeutic intervention and a multifactorial approach that considers the individual initiators of AD development. Current knowledge of AD includes the understanding of pathophysiology, risk factors, biomarkers, and the evolving patterns of biomarker abnormalities. This knowledge is essential in identifying potential molecular targets for new drug development. This review summarizes promising AD drug candidates, many of which are currently in phase 2 or 3 clinical trials. New agents are classified according to the Common Alzheimer's Disease Research Ontology (CADRO). The main targets of new drugs for AD are processes related to amyloid beta and tau neurotoxicity, neurotransmission, inflammation, metabolism and bioenergetics, synaptic plasticity, and oxidative stress. These interventions are aimed at preventing disease onset and slowing or eliminating disease progression. The efficacy of pharmacotherapy may be enhanced by combining these drugs with other treatments, antioxidants, and dietary supplements. Ongoing research into AD pathophysiology, risk factors, biomarkers, and the dynamics of biomarker abnormalities may contribute to the understanding of AD and offer hope for effective therapeutic strategies in the near future.
- MeSH
- Alzheimerova nemoc * metabolismus farmakoterapie MeSH
- biologické markery * metabolismus MeSH
- klinické zkoušky jako téma * metody MeSH
- lidé MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Jsou shrnuty poznatky o rizikových faktorech a biomarkerech Alzheimerovy nemoci (AD), které jsou základem pro poznání patofyziologie onemocnění a pro rozpoznání buněčných cílů nových léčiv. Hlavními cíli nových léčiv pro AD jsou procesy spojené s neurotoxicitou amyloidu beta (A?) a tau proteinu, narušenou neurotransmisí, metabolickou dysregulací, mitochondriální dysfunkcí, oxidačním stresem, neurozánětem, neuroplasticitou, proteostází a proteinopatií. Některá nová léčiva jsou zaměřena na více asociovaných buněčných procesů, jako je cholinergní deplece, toxicita glutamátu, agregace A?, hyperfosforylace tau, oxidační stres a aktivita mitochondriálních proteinů. Farmakologická intervence při AD s potenciálem být kauzální zahrnuje regulaci produkce, eliminace, šíření a vzájemné interakce oligomerů a agregátů A? (k prevenci nástupu onemocnění), oligomerů tau a neurofibrilárních klubek (k eliminaci progrese onemocnění) a mitochondriální dysfunkce (ke snížení progrese neurodegenerace). Účinnost farmakoterapie lze zvýšit vhodnou kombinací s jinými lékovými i nelékovými intervencemi a doplňky stravy.
Knowledge about risk factors and biomarkers of Alzheimer ́s disease (AD), which are the basis for understanding the pathophysiology of the disease and for identifying the cellular targets for new drugs, is summarized. The main targets of new AD drugs are processes associated with amyloid beta (A?) and tau neurotoxicity, impaired neurotransmission metabolic dysregulation, mitochondrial dysfunction, oxidative stress, neuroinflammation, neuroplasticity, proteostasis, and proteinopathy. Some new drugs target multiple associated cellular processes, such as cholinergic depletion, glutamate toxicity, A? aggregation, tau hyperphosphorylation, oxidative stress, and mitochondrial protein activity. Pharmacological intervention in AD with the potential to be causal includes targeting the production, elimination, distribution, and interactions of A? oligomers and aggregates (to prevent disease onset), tau oligomers and neurofibrillary tangles (to prevent disease progression), and mitochondrial dysfunction (to reduce neurodegeneration progression). The effectiveness of pharmacotherapy may be enhanced by appropriate combination with other drug and non-drug interventions and nutritional supplements.
[Alzheimer ́s disease: pathophysiology and hypotheses]
sou shrnuty biologické hypotézy Alzheimerovy nemoci (AD) založené na poznatcích o patofyziologii AD, které slouží jako východiska pro farmakoterapeutické strategie. Pokroky v poznání úlohy rizikových faktorů a biomarkerů AD v neurodegenerativních procesech umožňují jednak upřesnění stávajících hypotéz nebo tvorbu nových, jednak zlepšení diagnostiky onemocnění, sledování progrese onemocnění a nalezení molekulárních cílů nových léčiv. Kromě amyloidové a tau hypotézy, resp. patologie amyloidu beta a tau proteinu, se při vývoji nových léčiv a studiu mechanismů jejich účinků vychází především z hypotézy mitochondriální, metabolické, neurozánětlivé, oxidačního stresu, synaptoplastické a neurotransmiterové. Významné pro pochopení patofyziologie AD se jeví poznatky o vzájemném propojení, interakcích a synergiích buněčných patologických procesů považovaných za klíčové v hypotézách AD.
Biological hypotheses of Alzheimer ́s disease (AD) based on knowledge about the pathophysiology of AD are summarized, which serve as starting points for pharmacotherapeutic strategies. Advances in the knowledge of the role of risk factors and biomarkers of AD in neurodegenerative processes allow the refinement of existing hypotheses or the generation of new ones, as well as the improvement of disease diagnostics, the monitoring of disease progression, and the discovery of molecular targets for new drugs. In addition to the amyloid and tau hypothesis, respectively the pathology of amyloid beta and tau protein, the mitochondrial, metabolic, neuroinflammatory, oxidative stress, synaptoplastic, and neurotransmitter hypotheses are being used to develop new drugs and to study the mechanisms of their action. Important for the understanding of the pathophysiology of AD is the knowledge about the interrelationships, interactions, and synergies of the cellular pathological processes that are considered to be key in the various AD hypotheses.
- MeSH
- Alzheimerova nemoc * diagnóza etiologie patofyziologie MeSH
- amyloidní beta-protein metabolismus toxicita MeSH
- biologické markery analýza MeSH
- lidé MeSH
- mitochondrie metabolismus patologie MeSH
- nervový přenos fyziologie MeSH
- neuroplasticita fyziologie MeSH
- proteiny tau metabolismus toxicita MeSH
- rizikové faktory MeSH
- signální transdukce fyziologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
- přehledy MeSH
The progress in understanding the pathogenesis and treatment of Alzheimer's disease (AD) is based on the recognition of the primary causes of the disease, which can be deduced from the knowledge of risk factors and biomarkers measurable in the early stages of the disease. Insights into the risk factors and the time course of biomarker abnormalities point to a role for the connection of amyloid beta (Aβ) pathology, tau pathology, mitochondrial dysfunction, and oxidative stress in the onset and development of AD. Coenzyme Q10 (CoQ10) is a lipid antioxidant and electron transporter in the mitochondrial electron transport system. The availability and activity of CoQ10 is crucial for proper mitochondrial function and cellular bioenergetics. Based on the mitochondrial hypothesis of AD and the hypothesis of oxidative stress, the regulation of the efficiency of the oxidative phosphorylation system by means of CoQ10 can be considered promising in restoring the mitochondrial function impaired in AD, or in preventing the onset of mitochondrial dysfunction and the development of amyloid and tau pathology in AD. This review summarizes the knowledge on the pathophysiology of AD, in which CoQ10 may play a significant role, with the aim of evaluating the perspective of the pharmacotherapy of AD with CoQ10 and its analogues.
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Both the discovery of biomarkers of schizophrenia and the verification of biological hypotheses of schizophrenia are an essential part of the process of understanding the etiology of this mental disorder. Schizophrenia has long been considered a neurodevelopmental disease whose symptoms are caused by impaired synaptic signal transduction and brain neuroplasticity. Both the onset and chronic course of schizophrenia are associated with risk factors-induced disruption of brain function and the establishment of a new homeostatic setpoint characterized by biomarkers. Different risk factors and biomarkers can converge to the same symptoms of schizophrenia, suggesting that the primary cause of the disease can be highly individual. Schizophrenia-related biomarkers include measurable biochemical changes induced by stress (elevated allostatic load), mitochondrial dysfunction, neuroinflammation, oxidative and nitrosative stress, and circadian rhythm disturbances. Here is a summary of selected valid biological hypotheses of schizophrenia formulated based on risk factors and biomarkers, neurodevelopment, neuroplasticity, brain chemistry, and antipsychotic medication. The integrative neurodevelopmental-vulnerability-neurochemical model is based on current knowledge of the neurobiology of the onset and progression of the disease and the effects of antipsychotics and psychotomimetics and reflects the complex and multifactorial nature of schizophrenia.
17β-hydroxysteroid dehydrogenase type 10 (17β-HSD10) is a multifunctional mitochondrial enzyme and putative drug target for the treatment of various pathologies including Alzheimer's disease or some types of hormone-dependent cancer. In this study, a series of new benzothiazolylurea-based inhibitors were developed based on the structure-activity relationship (SAR) study of previously published compounds and predictions of their physico-chemical properties. This led to the identification of several submicromolar inhibitors (IC50 ∼0.3 μM), the most potent compounds within the benzothiazolylurea class known to date. The positive interaction with 17β-HSD10 was further confirmed by differential scanning fluorimetry and the best molecules were found to be cell penetrable. In addition, the best compounds weren't found to have additional effects for mitochondrial off-targets and cytotoxic or neurotoxic effects. The two most potent inhibitors 9 and 11 were selected for in vivo pharmacokinetic study after intravenous and peroral administration. Although the pharmacokinetic results were not fully conclusive, it seemed that compound 9 was bioavailable after peroral administration and could penetrate into the brain (brain-plasma ratio 0.56).
Mitochondrial dysfunction is involved in the pathophysiology of psychiatric and neurodegenerative disorders and can be used as a modulator and/or predictor of treatment responsiveness. Understanding the mitochondrial effects of antidepressants is important to connect mitochondria with their therapeutic and/or adverse effects. Pig brain-isolated mitochondria were used to evaluate antidepressant-induced changes in the activity of electron transport chain (ETC) complexes, monoamine oxidase (MAO), mitochondrial respiratory rate, and ATP. Bupropion, escitalopram, fluvoxamine, sertraline, paroxetine, and trazodone were tested. All tested antidepressants showed significant inhibition of complex I and IV activities at high concentrations (50 and 100 μmol/L); complex II + III activity was reduced by all antidepressants except bupropion. Complex I-linked respiration was reduced by escitalopram >> trazodone >> sertraline. Complex II-linked respiration was reduced only by bupropion. Significant positive correlations were confirmed between complex I-linked respiration and the activities of individual ETC complexes. MAO activity was inhibited by all tested antidepressants, with SSRIs causing a greater effect than trazodone and bupropion. The results indicate a probable association between the adverse effects of high doses of antidepressants and drug-induced changes in the activity of ETC complexes and the respiratory rate of mitochondria. In contrast, MAO inhibition could be linked to the antidepressant, procognitive, and neuroprotective effects of the tested antidepressants.
- Publikační typ
- časopisecké články MeSH
Mitochondrial dysfunction is an important cellular hallmark of aging and neurodegeneration. Platelets are a useful model to study the systemic manifestations of mitochondrial dysfunction. To evaluate the age dependence of mitochondrial parameters, citrate synthase activity, respiratory chain complex activity, and oxygen consumption kinetics were assessed. The effect of cognitive impairment was examined by comparing the age dependence of mitochondrial parameters in healthy individuals and those with neuropsychiatric disease. The study found a significant negative slope of age-dependence for both the activity of individual mitochondrial enzymes (citrate synthase and complex II) and parameters of mitochondrial respiration in intact platelets (routine respiration, maximum capacity of electron transport system, and respiratory rate after complex I inhibition). However, there was no significant difference in the age-related changes of mitochondrial parameters between individuals with and without cognitive impairment. These findings highlight the potential of measuring mitochondrial respiration in intact platelets as a means to assess age-related mitochondrial dysfunction. The results indicate that drugs and interventions targeting mitochondrial respiration may have the potential to slow down or eliminate certain aging and neurodegenerative processes. Mitochondrial respiration in platelets holds promise as a biomarker of aging, irrespective of the degree of cognitive impairment.
- Publikační typ
- časopisecké články MeSH
Damage or loss of brain cells and impaired neurochemistry, neurogenesis, and synaptic and nonsynaptic plasticity of the brain lead to dementia in neurodegenerative diseases, such as Alzheimer's disease (AD). Injury to synapses and neurons and accumulation of extracellular amyloid plaques and intracellular neurofibrillary tangles are considered the main morphological and neuropathological features of AD. Age, genetic and epigenetic factors, environmental stressors, and lifestyle contribute to the risk of AD onset and progression. These risk factors are associated with structural and functional changes in the brain, leading to cognitive decline. Biomarkers of AD reflect or cause specific changes in brain function, especially changes in pathways associated with neurotransmission, neuroinflammation, bioenergetics, apoptosis, and oxidative and nitrosative stress. Even in the initial stages, AD is associated with Aβ neurotoxicity, mitochondrial dysfunction, and tau neurotoxicity. The integrative amyloid-tau-mitochondrial hypothesis assumes that the primary cause of AD is the neurotoxicity of Aβ oligomers and tau oligomers, mitochondrial dysfunction, and their mutual synergy. For the development of new efficient AD drugs, targeting the elimination of neurotoxicity, mutual potentiation of effects, and unwanted protein interactions of risk factors and biomarkers (mainly Aβ oligomers, tau oligomers, and mitochondrial dysfunction) in the early stage of the disease seems promising.
