At the terminus of the O2 cascade, mitochondria play an important role in O2 utilisation and energy conservation, with adaptive modifications occasionally shared among hypoxia-tolerant species. Here, we sought to determine whether mitochondrial adaptations in brain tissue explain the hypoxia tolerance of New Zealand triplefin fishes (Tripterygiidae). We compared two intertidal species (Bellapiscis medius and Forsterygion lapillum), both likely adapted to hypoxia-reoxygenation exposures, and two subtidal species (F. varium and F. malcomi), which inhabit normoxic waters. To assess hypoxia tolerance, we determined loss of equilibrium (LOE) during hypoxia exposure and measured the critical O2 tension (Pcrit). Intertidal species displayed superior hypoxia tolerance as assessed by LOE and also had lower Pcrit (LOE versus Pcrit R2 = 0.99). High-resolution respirometry was used to measure mitochondrial respiration in homogenate and permeabilised fragments of brain. While a weak relationship was apparent between mitochondrial O2 binding affinity (mP50) and LOE, maximum phosphorylating O2 consumption (OxPhos) and O2 catalytic rates were strongly correlated with hypoxia tolerance. Although cytochrome-c-oxidase activity was highest in the most hypoxia-tolerant species B. medius, it was only weakly correlated with hypoxia tolerance across species. Notably, the high OxPhos capacity of intertidal species was not associated with higher whole animal resting O2 consumption, suggesting intertidal species maintain high capacity for ATP production without incurring increased basal energetic costs. While somewhat paradoxical, the low Pcrit/high OxPhos strategy of intertidal species may provide flexibility in the dynamic intertidal environment where short, severe periods of hypoxia are interspersed with high energy demand environmental conditions, including acute warming.

ABSTRACTAging is an inevitable consequence for all organisms. According to the mitochondrial free radical theory of aging (MFRTA), reactive oxygen species (ROS), which are predominantly generated in mitochondria, are assumed to play a key role. Calorie restriction (CR) delays aging by improving mitochondrial function; however, the molecular mechanisms underlying the effects of ROS and CR on mitochondria remain poorly understood. Oxidative protein modifications in mitochondrial proteins from the heart and cerebrum of young (6.5 months) and old (27 months) rats were quantified and the effects of short‐term and lifelong CR interventions were investigated. Mass spectrometry was leveraged to achieve an unbiased and comprehensive analysis of various types of oxidative postranslational modifications (oxPTMs). Contrary to the MFRTA, aging did not cause significant increases in mitochondrial protein oxidation in the heart and cerebrum. CR markedly diminished the overall level of oxPTMs in the heart, particularly in transmembrane proteins. Similarly, the level of oxidative modification of transmembrane proteins in cerebrum was reduced by CR, whereas it perplexingly increased in mitochondrial proteins. The absolute level of oxidized mitochondrial protein was always higher in the heart than in the cerebrum under all conditions. Carbonylation, a prevalent marker of protein oxidation and aging, increased in the heart with age and was notably reduced by CR. However, this trend was not consistent in cerebrum or for some other types of oxPTMs. Therefore, protein oxidation in the heart and cerebrum exhibits distinct responses to chronological aging and dietary interventions, with the latter exerting a stronger influence.

Aging increases susceptibility to high-fat diet-induced neurobehavioral and mitochondrial dysfunction in zebrafish.

Neuroinflammation plays a central role in a wide spectrum of neurological diseases, driven generally by reactive microglia and astrocytes. Inflammatory stimulation of microglia and astrocytes leads to a metabolic shift from oxidative phosphorylation (OXPHOS) to glycolysis, which is required to support pro-inflammatory effector functions. This metabolic reprogramming is associated with impaired mitochondrial dynamics, including reduced biogenesis, increased fragmentation, and loss of membrane potential. Targeting microglia and astrocyte metabolism may offer a novel therapeutic approach for modulating neuroinflammation and restoring homeostatic immune functions. Here, we examined the potential of 2-Deoxy-D-Glucose (2DG), a glycolysis inhibitor, to attenuate neuroinflammation by restoring mitochondrial dynamics. In BV2 and primary glial cultures, low-dose 2DG reversed LPS-induced metabolic reprogramming, restoring OXPHOS, reducing mitochondrial fragmentation, and enhancing biogenesis. In vivo, it preserved spare respiratory capacity and increased complex-V activity in brain mitochondria from LPS-treated mice without affecting oxidative stress. At a mechanistic level, 2DG restored activation of AMP-activated protein kinase, a master regulator of mitochondrial dynamics. In conjunction with these metabolic effects, 2DG suppressed LPS-induced pro-inflammatory gene expression while enhancing markers associated with the resolution of inflammation and tissue repair. Critically, systemic low-dose 2DG reduced neuroinflammation and restored immune homeostasis in two LPS-induced mouse models, highlighting its therapeutic potential in neurological disorders.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-22677-w.

Mid-life obesity is a major risk factor for neurodegenerative diseases, with mitochondrial and cerebrovascular dysfunction considered key mediators. Lysine acetylation is a reversible post-translational modification that regulates several mitochondrial metabolic and biochemical processes. The present study investigatedthe sex-dependent effects of brain lysine acetylation and cerebrovascular and cognitive health in a high fat diet (HFD)-induced obesity mouse model. We hypothesize that a HFD will cause an increase in acetylation, dysregulating mitochondrial respiration, potentially due to the decline in overall cerebrovascular health. Six-month-old C57/Bl6 mice (M/F) were placed on a 60% HFD or normal chow (CON) for 4months. Changes in cerebral blood flux (CBF), behavioural testing, glucose tolerance testing and body composition were tested. Brain lysates were probed for various substrate utilizations, bioenergetics proteins and lysine acetylation. A HFD resulted in global metabolic dysregulation, with a substantial increase in weight and fat mass, with a greater increase in female mice; however, no cognitive changes were noted. Additionally, unlike female mice, males demonstrated a decrease in CBF after a HFD. Brain lysine acetylation was decreased in male HFD mice but increased in female HFD mice. Similarly, acetylation levels of fatty acid oxidation protein (long-chain acyl-CoA dehydrogenase), glucose oxidation proteins (pyruvate dehydrogenase, pyruvate carboxylase) and electron transport chain complex I (NDUFB8) and IV (MTCO1) proteins were decreased in male and increased in female brains after a HFD. In summary, our findings propose lysine acetylation as a novel and potential regulatory mechanism that impacts vascular and metabolic function in the brain mitochondria in a sex-dependent manner.

Mitochondrial metabolic flux alterations are critical drivers of acute ischemia-reperfusion (IR) brain injury. Reverse electron transfer (RET), defined as the upstream flow of electrons from the quinone pool to complex I, is a major source of pathological reactive oxygen species (ROS) under stress conditions. In an in vivo brain IR model, oxygen deprivation induces the buildup of RET-supporting substrates, with glycerol 3-phosphate identified as the dominant contributor in addition to succinate. Rapid oxidation of these substrates by brain mitochondria upon reoxygenation drives massive ROS production, while also leading to over-reduction and dissociation of the complex I flavin mononucleotide (FMN) cofactor. The resulting FMN-deficient complex I becomes catalytically impaired, unable to oxidize NADH or to produce ROS.To mitigate RET and preserve complex I function, we used transgenic mice xenotopically expressing alternative oxidase (AOX). This enzyme bypasses complexes III and IV by directly oxidizing the reduced quinone pool and passing electrons onto molecular oxygen. AOX expression did not alter complex I abundance, supercomplexes assembly, or basal respiration rates, but effectively diverted electrons from the quinone pool, decreasing RET flux via complex I and limiting ROS generation during IR. For the first time we showed that AOX expression and attenuation of RET preserved complex I FMN binding, suppressed oxidative stress, and conferred neuroprotection in vivo. Our findings reveal a novel strategy for rewiring mitochondrial electron flux to mitigate initial IR brain injury, highlighting modulation of the quinone pool by AOX as a potential therapeutic strategy for IR.

HPDL gene mutations have recently been linked to neurodevelopmental disorders with variable presentations, ranging from mild hereditary spastic paraplegia to severe infantile neurodegeneration. While the HPDL protein’s role is unknown, it is highly expressed in brain mitochondria. Here we report a case of a 19- month-old male with a homozygous HPDL gene mutation presented with global developmental delay, epilepsy, laryngomalacia post-arytenoidectomy, swallowing dysfunction, and spasticity. He exhibited significant dysmorphic features and recurrent convulsions, and required nasogastric feeding due to oral feeding difficulties.

A heteropolysaccharide from Hypsizygus ulmarius fruit bodies attenuates D-galactose-induced cognitive decline by enhancing mitochondrial function and improving antioxidant activity in mice.

Mitochondrial dysfunction and accumulation of α-synuclein aggregates are hallmarks of the neurodegenerative Parkinson’s disease and may be interconnected. To investigate the interplay between α-synuclein and brain mitochondria at near atomic structural level, we apply NMR and identify α-synuclein protein interactors using limited proteolysis-coupled mass spectrometry (LiP-MS). Several of the proteins identified are related to ATP synthesis and homeostasis and include subunits of ATP synthase and the adenylate kinase AK2. Furthermore, our data suggest that α-synuclein interacts with the Parkinson’s disease-related protein DJ1. NMR analysis demonstrates that both AK2 and DJ1 bind to the C-terminus and other segments of α-synuclein. Using a functional assay for AK2, we show that monomeric α-synuclein has an activating effect, whereas C-terminally truncated α-synuclein and α-synuclein in an amyloid fibrillar state have no significant effect on AK2 activity. Our results suggest that α-synuclein modulates ATP homeostasis in a manner dependent on its conformation and its C-terminal acidic segment.

Our brain's mitochondria may play a crucial role in the onset of sleep

Some studies performed in our laboratory on pyrrole and its derivatives pointed towards the enrichment of the evaluations of these promising chemical structures for the potential treatment of neurodegenerative conditions in general and Parkinson's disease in particular. A classical Paal-Knorr cyclization approach is applied to synthesize the basic hydrazine used for the formation of the designed series of hydrazones (15a-15g). The potential neurotoxic and neuroprotective effects of the newly synthesized derivatives were investigated in vitro using different models of induced oxidative stress at three subcellular levels (rat brain synaptosomes, mitochondria, and microsomes). The results identified as the least neurotoxic molecules, 15a, 15d, and 15f applied at a concentration of 100 µM to the isolated fractions. In addition, the highest statistically significant neuroprotection was observed for 15a and 15d at a concentration of 100 µM using three different injury models on subcellular fractions, including 6-hydroxydopamine in rat brain synaptosomes, tert-butyl hydroperoxide in brain mitochondria, and non-enzyme-induced lipid peroxidation in brain microsomes. The hMAOA/MAOB inhibitory activity of the new compounds was studied at a concentration of 1 µM. The lack of a statistically significant hMAOA inhibitory effect was observed for all tested compounds, except for 15f, which showed 40% inhibitory activity. The most prominent statistically significant hMAOB inhibitory effect was determined for 15a, 15d, and 15f, comparable to that of selegiline. The corresponding selectivity index defined 15f as a non-selective MAO inhibitor and all other new hydrazones as selective hMAOB inhibitors, with 15d indicating the highest selectivity index of >471. The most active and least toxic representative (15d) was evaluated in vivo on Rotenone based model of Parkinson's disease. The results revealed no microscopically visible alterations in the ganglion and glial cells in the animals treated with rotenone in combination with 15d.

Exercise supports healthy aging in the brain leading to adaptations that slow cognitive decline, including increasing neurogenesis in the hippocampus and promoting the maintenance of mitochondrial function. Evidence demonstrates that exercise stimulates the release of factors, exerkines, that modulate systemic benefits. Extracellular vesicles (EVs) facilitate inter-organ crosstalk in response to exercise by disseminating exerkines. The liver, crucial to maintaining systemic metabolic homeostasis, undergoes substantial changes with exercise and is central to exercise induced adaptations that promote metabolic health. Taken together, these findings point to exercise induced liver derived EVs as a critical area of study in potentially mediating the benefit of exercise to brain health. Male and female 6-month old Fisher (F344) rats were randomized to sedentary or acute exercise conditions (30-minute treadmill running at 70-80% VO 2 max). Immediately after exercise, the common hepatic and portal veins were cannulated for blood sampling in anesthetized rats. EVs were isolated via serial ultracentrifugation and underwent global, untargeted proteomic analysis (n=4/5). Rat primary cortical neurons were cultured from isolated embryonic cortices and treated with pooled sedentary or exercised, male or female, common hepatic vein EVs for 4 hours at a concentration of 2.5ug/mL (n=3). Serum from which the EV populations were isolated was used as a control. Basal mitochondrial respiration was measured using a Seahorse XF. In females, we identified 119 significantly differentially expressed proteins (DEPs) in common hepatic vein EVs between exercise and sedentary conditions, 13 of which were only identified with exercise. While in males, we identified 120 DEPs, 7 of which were unique to exercise. In rat primary cortical neurons male derived hepatic EVs promoted increased basal mitochondrial respiration, predominantly driven by exercise (main effect of EVs, p<0.05), while exercise promoted increased basal mitochondrial respiration, largely driven by hepatic EVs, in females (main effect of exercise, p<0.05). Here we demonstrate that a single bout of exercise stimulates the release of hepatic EVs, with unique and sexually dimorphic proteomic profiles, that are capable of influencing mitochondrial respiration in primary neurons. These data suggest that the liver may mediate exercise induced effects on brain mitochondria through EVs. * MoTrPAC-generated data have undergone preliminary analysis by the authors of this work; results presented here do not represent the final consensus analysis by MoTrPAC. U01AG070928 (The Molecular Transducers of Physical Activity Consortium on behalf of the preclinical animal study sites 2 for the MoTrPAC Study Group) and by FWB, RSR, and JPT. This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

Abstract BackgroundAlzheimer’s disease (AD) risk and progression are significantly influenced by ApoE genotypes, with ApoE4 increasing and ApoE2 decreasing the susceptibility compared to ApoE3. Understanding metabolic pathways affected by ApoE genotypes will help decipher disease development and identify new therapeutic targets.MethodThis study investigates the impact of ApoE genotypes on aging brain metabolic trajectories using human ApoE‐targeted replacement mice. Applying Biocrates P180 targeted metabolomics platform, we analyzed the metabolic impact of ApoE2/2, ApoE3/3, and ApoE4/4 on fatty acid β‐oxidation, amino acids, and phospholipids, which are known to be altered in AD. Furthermore, we compared our rodent model results with human dorsolateral prefrontal cortex data from the Religious Orders Study/Memory and Aging Project (ROS‐MAP).ResultWe found aging mice carrying ApoE2/2 had altered branch‐chain amino acid metabolism and increased C5 acylcarnitine and its ratio to precursor isoleucine, pointing towards increased β‐oxidation and branched‐chain amino acid (BCAA) utilization. Furthermore, ROS‐MAP data revealed the ApoE2 genotype affects similar areas of metabolism in humans. Additionally, our data provide comprehensive insight into age‐related metabolic changes of the current mice model, independent of ApoE genotype, among phospholipids, sphingomyelins, amino acids, and biogenic amines. Many of the observed differences are also known aging markers in humans, with a connection to cognition and Alzheimer’s disease.ConclusionTogether, these results suggest a potential involvement of ApoE2/2 genotype in energy metabolism and characterize the current mice model for further study of ApoE in AD, brain aging, and brain BCAA utilization for energy.

Glucose is the main energy source of the brain, yet recent studies demonstrate that fatty acid oxidation (FAO) plays a relevant role in the pathogenesis of central nervous system disorders. We evaluated FAO in brain mitochondria under physiological conditions, in the aging brain, and after stroke. Using high-resolution respirometry we compared medium-chain (MC, octanoylcarnitine) and long-chain (LC, palmitoylcarnitine) acylcarnitines as substrates of β-oxidation in the brain. The protocols developed avoid FAO overestimation by malate-linked anaplerotic activity in brain mitochondria. The capacity of FA oxidative phosphorylation (F-OXPHOS) with palmitoylcarnitine was up to 4 times higher than respiration with octanoylcarnitine. The optimal concentration of palmitoylcarnitine was 10 μM which corresponds to the total concentration of LC acylcarnitines in the brain. Maximal respiration with octanoylcarnitine was reached at 20 μM, however, this concentration exceeds MC acylcarnitine concentrations in the brain 15 times. F-OXPHOS capacity was highest in mouse cerebellum, intermediate in cortex, prefrontal cortex, and hypothalamus, and hardly detectable in hippocampus. F-OXPHOS capacity was 2-fold lower and concentrations of LC acylcarnitines were 2-fold higher in brain of aged rats. A similar trend was observed in the rat model of endothelin-1-induced stroke, but reduction of OXPHOS capacity was not limited to FAO. In conclusion, although FAO is not a dominant pathway in brain bioenergetics, it deserves specific attention in studies of brain metabolism.

Individuals diagnosed with Parkinson’s disease (PD) often exhibit heightened susceptibility to cardiac dysfunction, reflecting a complex interaction between these conditions. The involvement of mitochondrial dysfunction in the development and progression of cardiac dysfunction and PD suggests a plausible commonality in some aspects of their molecular pathogenesis, potentially contributing to the prevalence of cardiac issues in PD. Mitochondria, crucial organelles responsible for energy production and cellular regulation, play important roles in tissues with high energetic demands, such as neurons and cardiac cells. Mitochondrial dysfunction can occur in different and non-mutually exclusive ways; however, some mechanisms include alterations in mitochondrial dynamics, compromised bioenergetics, biogenesis deficits, oxidative stress, impaired mitophagy, and disrupted calcium balance. It is plausible that these factors contribute to the increased prevalence of cardiac dysfunction in PD, suggesting mitochondrial health as a potential target for therapeutic intervention. This review provides an overview of the physiological mechanisms underlying mitochondrial quality control systems. It summarises the diverse roles of mitochondria in brain and heart function, highlighting shared pathways potentially exhibiting dysfunction and driving cardiac comorbidities in PD. By highlighting strategies to mitigate dysfunction associated with mitochondrial impairment in cardiac and neural tissues, our review aims to provide new perspectives on therapeutic approaches.

Alternative oxidase (AOX) is an enzyme that transfers electrons from reduced quinone directly to oxygen without proton translocation. When AOX from Ciona intestinalis is xenotopically expressed in mice, it can substitute the combined electron-transferring activity of mitochondrial complexes III/IV. Here, we used brain mitochondria from AOX-expressing mice with such a chimeric respiratory chain to study respiratory control bioenergetic mechanisms.AOX expression did not compromise the function of the mammalian respiratory chain at physiological conditions, however the complex IV inhibitor cyanide only partially blocked respiration by AOX-containing mitochondria. The relative fraction of cyanide-insensitive respiration increased at lower temperatures, indicative of a temperature-controlled attenuation of mammalian respiratory enzyme activity.As AOX does not translocate protons, the mitochondrial transmembrane potential in AOX-containing mitochondria was more sensitive to cyanide during succinate oxidation than during malate/pyruvate-supported respiration. High concentrations of cyanide fully collapsed membrane potential during oxidation of either succinate or glycerol 3-phosphate, but not during malate/pyruvate-supported respiration. This confirms AOX's electroneutral redox activity and indicates differences in the proton-translocating capacity of dehydrogenases upstream of the ubiquinone pool. Our respiration data refutes previous proposals for quinone partitioning within the supercomplexes of the respiratory chain, instead supporting the concept of a single homogeneous, freely diffusing quinone pool.Respiration with either succinate or glycerol 3-phosphate promotes reverse electron transfer (RET) towards complex I. AOX expression significantly decreased RET-induced ROS generation, with the effect more pronounced at low temperatures. Inhibitor-sensitivity analysis showed that the AOX-induced decrease in H2O2 release is due to the lower contribution of complex I to net ROS production during RET.Overall, our findings provide new insights into the role of temperature as a mechanism to control respiration and highlight the utility of AOX as a genetic tool to characterize both the distinct pathways of oxygen reduction and the role of redox control in RET.

Background and aimWe recently identified protein kinase N1 (PKN1) as a master regulator of brain development. However, its function in the adult brain has not been clearly established. In this study, we assessed the cerebral energetic phenotype of wildtype (WT) and global Pkn1 knockout (Pkn1−/−) animals under physiological and pathophysiological conditions. MethodsCerebral energy metabolism was analyzed by 13C6-glucose tracing in vivo and real time seahorse analysis of extracellular acidification rates as well as mitochondrial oxygen consumption rates (OCR) of brain slice punches in vitro. Isolated WT and Pkn1−/− brain mitochondria were tested for differences in OCR with different substrates. Metabolite levels were determined by mass spectrometric analysis in brain slices under control and energetic stress conditions, induced by oxygen-glucose deprivation and reperfusion, an in vitro model of ischemic stroke. Differences in enzyme activities were assessed by enzymatic assays, western blotting and bulk RNA sequencing. A middle cerebral artery occlusion stroke model was used to analyze lesion volumes and functional recovery in WT and Pkn1−/− mice. ResultsPkn1 deficiency resulted in a remarkable upregulation of cerebral energy metabolism, in vivo and in vitro. This was due to two separate mechanisms involving an enhanced glycolytic flux and higher pyruvate-induced mitochondrial OCR. Mechanistically we show that Pkn1−/− brain tissue exhibits an increased activity of the glycolysis rate-limiting enzyme phosphofructokinase. Additionally, glucose-1,6-bisphosphate levels, a metabolite that increases mitochondrial pyruvate uptake, were elevated upon Pkn1 deficiency. Consequently, Pkn1−/− brain slices had more ATP and a greater accumulation of ATP degradation metabolites during energetic stress. This translated into increased phosphorylation and activity of adenosine monophosphate (AMP)-activated protein kinase (AMPK) during in vitro stroke. Accordingly, Pkn1−/− brain slices showed a post-ischemic transcriptional upregulation of energy metabolism pathways and Pkn1 deficiency was strongly protective in in vitro and in vivo stroke models. While inhibition of mitochondrial pyruvate uptake only moderately affected the protective phenotype, inhibition of AMPK in Pkn1−/− slices increased post-ischemic cell death in vitro. ConclusionThis is the first study to comprehensively demonstrate an essential and unique role of PKN1 in cerebral energy metabolism, regulating glycolysis and mitochondrial pyruvate-induced respiration. We further uncovered a highly protective phenotype of Pkn1 deficiency in both, in vitro and in vivo stroke models, validating inhibition of PKN1 as a promising new therapeutic target for the development of novel stroke therapies.

Nausea serves as a protective mechanism in organisms to prevent excessive consumption of toxic substances. Due to the adverse effects of chemical anti-nausea drugs, there is a growing interest in using herbal remedies and natural antioxidants. In this study, we evaluated the neuroprotective effects of quercetin (QU) and N-acetylcysteine (NAC) against oxidative damage induced by nausea. Emesis was induced in chickens using ipecac and copper sulfate (600 and 60mg/kg, orally, respectively). QU and NAC (with doses of 50, 100, 200mg/kg), and their combination were administered, along with a standard therapy (metoclopramide; MET 2mg/kg) for one-time. Mitochondrial function, lipid peroxidation (LPO), protein carbonyl (PC), glutathione level (GSH), and reactive oxygen species (ROS) as oxidative damage biomarkers were evaluated in the chicken's brain mitochondria. QU and NAC significantly reduced emesis induced by copper sulfate and ipecac compared to the control group (P<0.001). Significant differences in oxidative damage were observed in the groups received of copper sulfate and ipecac compared with control group. Levels of LPO, ROS, and PC were significantly decreased after the administration of QU and NAC in emesis induced by copper sulfate and ipecac. While, mitochondrial function and GSH levels were increased after the administration of QU and NAC. Combination therapy with QU and NAC yielded the most effective results. This study suggests that QU and NAC possess antiemetic effects through both peripheral and central mechanisms and exhibit neuroprotective effects against oxidative brain damage induced by emesis by increasing plasma antioxidants or scavenging free radicals.

High-resolution respirometry for measurement of fatty acid β-oxidation in brain mitochondria. A comparative study and application in ischemia and aging

Alzheimer’s disease (AD) is an age-dependent incurable neurodegenerative disorder accompanied by neuroinflammation, amyloid accumulation, and memory impairment. It begins decades before the first clinical symptoms appear, and identifying early biomarkers is key for developing disease-modifying therapies. We show now in a mouse model of AD that before any amyloid deposition the brains of 1.5-month-old mice contain increased levels of pro-inflammatory cytokines IL-1β and IL-6, decreased levels of nicotinic acetylcholine receptors (nAChRs) in the brain and brain mitochondria and increased amounts of α7 nAChR-bound Aβ1–42, along with impaired episodic memory and increased risk of apoptosis. Both acute (1-week-long) and chronic (4-month-long) treatments with α7-selective agonist PNU282987, starting at 1.5 months of age, were well tolerated. The acute treatment did not affect the levels of soluble Aβ1–42 but consistently upregulated the α7 nAChR expression, decreased the level of α7-Aβ1–42 complexes, and improved episodic memory of 1.5-month-old mice. The chronic treatment, covering the disease development phase, strongly upregulated the expression of all abundant brain nAChRs, reduced both free and α7-coupled Aβ1–42 within the brain, had anti-inflammatory and antiapoptotic effects, and potently upregulated cognition, thus identifying α7 nAChRs as both early biomarker and potent therapeutic target for fighting this devastating disease.