CSF and Plasma Cholinergic Markers in Patients With Cognitive Impairment

Micellar Choline-Acetyltransferase Complexes Exhibit Ultra-Boosted Catalytic Rate for Acetylcholine Synthesis-Mechanistic Insights for Development of Acetylcholine-Enhancing Micellar Nanotherapeutics

Choline-acetyltransferase (ChAT) is the key cholinergic enzyme responsible for the biosynthesis of acetylcholine (ACh), a crucial signaling molecule with both canonical neurotransmitter function and auto- and paracrine signaling activity in non-neuronal cells, such as lymphocytes and astroglia. Cholinergic dysfunction is linked to both neurodegenerative and inflammatory diseases. In this study, we investigated a serendipitous observation, namely that the catalytic rate of human recombinant ChAT (rhChAT) protein greatly differed in buffered solution in the presence and absence of Triton X-100 (TX100). At a single concentration of 0.05% (v/v), TX100 boosted the specific activity of rhChAT by 4-fold. Dose-response analysis within a TX100 concentration range of 0.8% to 0.008% (accounting for 13.7 mM to 0.013 mM) resulted in an S-shaped response curve, indicative of an over 10-fold boost in the catalytic rate of rhChAT. This dramatic boost was unlikely due to a mere structural stabilization since it remained even after the addition of 1.0 mg/mL gelatin to the ChAT solution as a protein stabilizer. Furthermore, we found that the catalytic function of the ACh-degrading enzyme, AChE, was unaffected by TX100, underscoring the specificity of the effect for ChAT. Examination of the dose-response curve in relation to the critical micelle concentration (CMC) of TX100 revealed that a boost in ChAT activity occurred when the TX100 concentration passed its CMC, indicating that formation of micelle-ChAT complexes was crucial. We challenged this hypothesis by repeating the experiment on Tween 20 (TW20), another non-ionic surfactant with ~3-fold lower CMC compared to TX100 (0.06 vs. 0.2 mM). The analysis confirmed that micelle formation is crucial for ultra-boosting the activity of ChAT. In silico molecular dynamic simulation supported the notion of ChAT-micelle complex formation. We hypothesize that TX100 or TW20 micelles, by mimicking cell-membrane microenvironments, facilitate ChAT in accessing its full catalytic potential by fine-tuning its structural stabilization and/or enhancing its substrate accessibility. These insights are expected to facilitate research toward the development of new cholinergic-enhancing therapeutics through the formulation of micelle-embedded ChAT nanoparticles.

Melatonin Attenuates Arsenic-Induced Neurotoxicity in Rats Through the Regulation of miR-34a/miR-144 in Sirt1/Nrf2 Pathway

Arsenic (As) exposure is known to cause several neurological disorders through various molecular mechanisms such as oxidative stress, apoptosis, and autophagy. In the current study, we assessed the effect of melatonin (Mel) on As-induced neurotoxicity. Thirty male Wistar rat were treated daily for 28 consecutive days. As (15 mg/kg, gavage) and Mel (10 and 20 mg/kg, i.p.) were administered to rats. Morris water maze test was done to evaluate learning and memory impairment in training days and probe trial. Oxidative stress markers including MDA and GSH levels, SOD activity, and HO-1 levels were measured. Besides, the levels of apoptosis (caspase 3, Bax/Bcl2 ratio) and autophagy markers (Sirt1, Beclin-1, and LC3 II/I ratio) as well as the expression of miR-144 and miR-34a in cortex tissue were determined. As exposure disturbed learning and memory in animals and Mel alleviated these effects. Also, Mel recovered cortex pathological damages and oxidative stress induced by As. Furthermore, As increased the levels of apoptosis and autophagy proteins in cortex, while Mel (20 mg/kg) decreased apoptosis and autophagy. Also, Mel increased the expression of miR-144 and miR-34a which inhibited by As. In conclusion, Mel administration attenuated As-induced neurotoxicity through anti-oxidative, anti-apoptotic, and anti-autophagy mechanisms, which may be recommended as a therapeutic target for neurological disorders.

Western diet consumption impairs memory function via dysregulated hippocampus acetylcholine signaling

Western diet (WD) consumption during early life developmental periods is associated with impaired memory function, particularly for hippocampus (HPC)-dependent processes. We developed an early life WD rodent model associated with long-lasting HPC dysfunction to investigate the neurobiological mechanisms mediating these effects. Rats received either a cafeteria-style WD (ad libitum access to various high-fat/high-sugar foods; CAF) or standard healthy chow (CTL) during the juvenile and adolescent stages (postnatal days 26-56). Behavioral and metabolic assessments were performed both before and after a healthy diet intervention period beginning at early adulthood. Results revealed HPC-dependent contextual episodic memory impairments in CAF rats that persisted despite the healthy diet intervention. Given that dysregulated HPC acetylcholine (ACh) signaling is associated with memory impairments in humans and animal models, we examined protein markers of ACh tone in the dorsal HPC (HPCd) in CAF and CTL rats. Results revealed significantly lower protein levels of vesicular ACh transporter in the HPCd of CAF vs. CTL rats, indicating chronically reduced ACh tone. Using intensity-based ACh sensing fluorescent reporter (iAChSnFr) in vivo fiber photometry targeting the HPCd, we next revealed that ACh release during object-contextual novelty recognition was highly predictive of memory performance and was disrupted in CAF vs. CTL rats. Neuropharmacological results showed that alpha 7 nicotinic ACh receptor agonist infusion in the HPCd during training rescued memory deficits in CAF rats. Overall, these findings reveal a functional connection linking early life WD intake with long-lasting dysregulation of HPC ACh signaling, thereby identifying an underlying mechanism for WD-associated memory impairments.

Circulating extracellular choline acetyltransferase regulates inflammation

BACKGROUND

Choline acetyltransferase (ChAT) is required for the biosynthesis of acetylcholine, the molecular mediator that inhibits cytokine production in the cholinergic anti-inflammatory pathway of the vagus nerve inflammatory reflex. Abundant work has established the biology of cytoplasmic ChAT in neurons, but much less is known about the potential presence and function of ChAT in the extracellular milieu.

OBJECTIVES

We evaluated the hypothesis that extracellular ChAT activity responds to inflammation and serves to inhibit cytokine release and attenuate inflammation.

METHODS

After developing novel methods for quantification of ChAT activity in plasma, we determined whether ChAT activity changes in response to inflammatory challenges.

RESULTS

Active ChAT circulates within the plasma compartment of mice and responds to immunological perturbations. Following the administration of bacterial endotoxin, plasma ChAT activity increases for 12-48 h, a time period that coincides with declining tumor necrosis factor (TNF) levels. Further, a direct activation of the cholinergic anti-inflammatory pathway by vagus nerve stimulation significantly increases plasma ChAT activity, whereas the administration of bioactive recombinant ChAT (r-ChAT) inhibits endotoxin-stimulated TNF production and anti-ChAT antibodies exacerbate endotoxin-induced TNF levels, results of which suggest that ChAT activity regulates endogenous TNF production. Administration of r-ChAT significantly attenuates pro-inflammatory cytokine production and disease activity in the dextran sodium sulfate preclinical model of inflammatory bowel disease. Finally, plasma ChAT levels are also elevated in humans with sepsis, with the highest levels observed in a patient who succumbed to infection.

CONCLUSION

As a group, these results support further investigation of ChAT as a counter-regulator of inflammation and potential therapeutic agent.

Presence of key cholinergic enzymes in human spermatozoa and seminal fluid†

Little is known about the non-neuronal spermic cholinergic system, which may regulate sperm motility and the acrosome reaction initiation process. We investigated the presence of the key acetylcholine (ACh)-biosynthesizing enzyme, choline acetyltransferase (ChAT), and the acetylcholine-degrading enzymes, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) and two ACh-receptors in human spermatozoa and seminal plasma. Fresh ejaculates were used for intra- and extracellular flow cytometric analysis of ChAT, AChE, BChE, and alpha-7-nicotinic and M1-muscarinic ACh-receptors in sperm. For determining the source of soluble enzymes, frozen seminal samples (n = 74) were selected on two bases: (1) from vasectomized (n = 37) and non-vasectomized (n = 37) subjects and (2) based on levels of alpha-glucosidase, fructose, or zinc to define sample subgroups with high or low fluid contribution from the epididymis and seminal vesicle, and prostate, respectively. Flow cytometric analyses revealed that ChAT was expressed intracellularly in essentially all spermatozoa. ChAT was also present in a readily membrane-detachable form at the extracellular membrane of at least 18% of the spermatozoa. These were also highly positive for intra- and extracellular BChE (>83%) and M1 (>84%) and α7 (>59%) ACh-receptors. Intriguingly, the sperm was negative for AChE. Analyses of seminal plasma revealed that spermatozoa and epididymides were major sources of soluble ChAT and BChE, whereas soluble AChE most likely originated from epididymides and seminal vesicles. Prostate had relatively minor contribution to the pool of the soluble enzymes in the seminal fluid. In conclusion, human spermatozoa exhibited a cholinergic phenotype and were one of the major sources of soluble ChAT and BChE in ejaculate. We also provide the first evidence for ChAT as an extracellularly membrane-anchored protein.

Association between serum iron, blood lead, cadmium, mercury, selenium, manganese and low cognitive performance in old adults from National Health and Nutrition Examination Survey (NHANES): a cross-sectional study

Cognitive decline is a public health problem for the world's ageing population. This study was to evaluate the relationships between serum Fe, blood Pb, Cd, Hg, Se and Mn and cognitive decline in elderly Americans. Data of this cross-sectional study were extracted from the National Health and Nutritional Examination Survey (NHANES 2011-2014). Cognitive performance was measured by the Consortium to Establish a Registry for Alzheimer's Disease (CERAD), Animal Fluency and Digit Symbol Substitution Test (DSST) tests. Weighted univariable and multivariate logistic regression analyses were used to assess the associations between six trace elements and low cognitive performance. Subgroup analyses based on diabetes and hypertension history were further assessed the associations. A total of 2002 adults over 60 years old were included. After adjusting covariates, elevated serum Fe levels were associated with the decreased risk of low cognitive performance, especially in the elderly without diabetes history and with hypertension history. High blood Cd levels were associated with the high odds of low cognitive performance in old adults with diabetes and hypertension history. Elevated blood Mn levels were connected with low cognitive performance in old hypertensive people. High blood Pb levels were related to the high odds of low cognitive performance, especially in the elderly without diabetes and hypertension history. High blood Se levels were linked to the decreased risk of low cognitive performance in all the elderly. Appropriate Fe, Se supplementation and Fe-, Se-rich foods intake, while reducing exposure to Pb, Cd and Mn may be beneficial for cognitive function in the elderly.

The Major Hypotheses of Alzheimer's Disease: Related Nanotechnology-Based Approaches for Its Diagnosis and Treatment

Alzheimer's disease (AD) is a well-known chronic neurodegenerative disorder that leads to the progressive death of brain cells, resulting in memory loss and the loss of other critical body functions. In March 2019, one of the major pharmaceutical companies and its partners announced that currently, there is no drug to cure AD, and all clinical trials of the new ones have been cancelled, leaving many people without hope. However, despite the clear message and startling reality, the research continued. Finally, in the last two years, the Food and Drug Administration (FDA) approved the first-ever medications to treat Alzheimer's, aducanumab and lecanemab. Despite researchers' support of this decision, there are serious concerns about their effectiveness and safety. The validation of aducanumab by the Centers for Medicare and Medicaid Services is still pending, and lecanemab was authorized without considering data from the phase III trials. Furthermore, numerous reports suggest that patients have died when undergoing extended treatment. While there is evidence that aducanumab and lecanemab may provide some relief to those suffering from AD, their impact remains a topic of ongoing research and debate within the medical community. The fact is that even though there are considerable efforts regarding pharmacological treatment, no definitive cure for AD has been found yet. Nevertheless, it is strongly believed that modern nanotechnology holds promising solutions and effective clinical strategies for the development of diagnostic tools and treatments for AD. This review summarizes the major hallmarks of AD, its etiological mechanisms, and challenges. It explores existing diagnostic and therapeutic methods and the potential of nanotechnology-based approaches for recognizing and monitoring patients at risk of irreversible neuronal degeneration. Overall, it provides a broad overview for those interested in the evolving areas of clinical neuroscience, AD, and related nanotechnology. With further research and development, nanotechnology-based approaches may offer new solutions and hope for millions of people affected by this devastating disease.

Therapeutic Strategies Aimed at Improving Neuroplasticity in Alzheimer Disease

Alzheimer disease (AD) is the most prevalent form of dementia among elderly people. Owing to its varied and multicausal etiopathology, intervention strategies have been highly diverse. Despite ongoing advances in the field, efficient therapies to mitigate AD symptoms or delay their progression are still of limited scope. Neuroplasticity, in broad terms the ability of the brain to modify its structure in response to external stimulation or damage, has received growing attention as a possible therapeutic target, since the disruption of plastic mechanisms in the brain appear to correlate with various forms of cognitive impairment present in AD patients. Several pre-clinical and clinical studies have attempted to enhance neuroplasticity via different mechanisms, for example, regulating glucose or lipid metabolism, targeting the activity of neurotransmitter systems, or addressing neuroinflammation. In this review, we first describe several structural and functional aspects of neuroplasticity. We then focus on the current status of pharmacological approaches to AD stemming from clinical trials targeting neuroplastic mechanisms in AD patients. This is followed by an analysis of analogous pharmacological interventions in animal models, according to their mechanisms of action.

Isoimperatorin therapeutic effect against aluminum induced neurotoxicity in albino mice

Background: Although aluminum (Al) is not biologically crucial to the human body, classical studies have demonstrated that excessive human exposure to Al can induce oxidative damage, neuroinflammatory conditions and neurotoxic manifestations implicated in Alzheimer's disease (AD). Exposure to Al was reported to be associated with oxidative damage, neuroinflammation, and to enhance progressive multiregional neurodegeneration in animal models. Several plant-derived natural biomolecules have been recently used to reduce the toxic effects of Al through decreasing the oxidative stress and the associated diseases. A good candidate still to be tested is an active natural furanocoumarin, the isoimperatorin (IMP) that can be extracted from Lemon and lime oils and other plants. Here, we examined the neuroprotective effects of IMP on aluminum chloride (AlCl3)-induced neurotoxicity in albino mice. Methods: Twenty-four male albino mice were used in this study. Mice were randomly devided into 5 groups. The first group was given distilled water as a control, the second group was given AlCl3 orally (10 mg/wt/day) starting from the 2nd week to the end of the 6th week, the third group received AlCl3 orally and IMP interperitoneally, i. p. (30 mg/wt/day) starting from week 2 till week 6 where IMP was supplement 1st and then 4 h later AlCl3 was given to mice. The fourth group received the control (IMP 30 mg/wt, i. p.) from the 2nd week till the end of the experiment. Rodent models of central nervous system (CNS) disorders were assessed using object location memory and Y-maze tests in 6th week began. Essential anti-inflammatory and oxidative stress indicators were evaluated, including interleukin-1 β (IL-1β), tumor necrosis factor α (TNF-α), malondialdehyde (MDA), total antioxidant capacity (TAC), and catalase activity (CAT). In addition, serum levels of brain neurotransmitters such as corticosterone, acetylcholine (ACh), dopamine and serotonin in brain homogenates were measured calorimetrically. Results: The study results revealed that the daily treatment of AlCl3 upregulated the TNF-α and IL-1β levels, increased MDA accumulation, and decreased TAC and CAT activity. In addition, aluminum induced a reduction in concentrations of ACh, serotonin and dopamine in the brain. However, IMP significantly ameliorates the effect of AlCl3 through modulating the antioxidant and regulating the inflammatory response through targeting Nrf2 (NF-E2-related factor 2) and mitogen-activated protein kinase (MAPK). Conclusion: Thus, IMP might be a promising treatment option for neurotoxicity and neurodegenerative diseases, such as Alzheimer's disease and Parkinson's disease, which are associated with neuro-inflammation and oxidative stress.

Salivary Aβ1-42 may be a quick-tested biomarker for clinical use in Alzheimer's disease: a meta-analysis

OBJECTIVE

Alzheimer's disease (AD) is the most prevalent form of dementia among the aging population. Cumulative studies aim to find non-invasive biomarkers in the early stages of AD. Saliva can be obtained easily, and salivary biomarkers have been proven effective in detecting neurodegenerative diseases. To find effective biomarkers in saliva and to help the diagnosis of AD, we performed a meta-analysis focusing on the salivary biomarkers (β-amyloid 1-42 (Aβ_1-42), total tau (t-tau), phosphorylated tau (p-tau) and acetylcholinesterase (AChE)) in AD.

METHODS

We conducted a systematic online search for eligible studies reporting data on salivary biomarkers reflecting Aβ_1-42, t-tau, p-tau, and AChE in AD cohorts versus controls. Biomarkers' performance was assessed in a random-effects meta-analysis with the ratio of mean (RoM).

RESULTS

A total of thirteen studies were included in the meta-analysis, of them seven involved salivary Aβ_1-42 (271 AD and 489 controls), five involved salivary t-tau (324 AD and 252 controls), four involved salivary p-tau (130 AD and 161 controls), and three involved salivary AChE (81 AD and 54 controls). AD showed significantly higher salivary Aβ_1-42 levels than control (ROM = 1.90 (95% CI 1.28-2.81, P = 0.001), while AD and control did not differ significantly on salivary t-tau, p-tau and AChE (ROM = 0.94, 95% CI 0.67-1.31, P = 0.72; ROM = 0.91, 95% CI 0.56-1.45, P = 0.68; ROM = 0.83, 95% CI 0.24-2.88, P = 0.77; respectively).

CONCLUSION

The pooled results provide evidence that salivary Aβ_1-42 may serve as a sensitive biomarker for AD; nevertheless, larger AD cohorts are required to further confirm the sensitivity and specificity of salivary Aβ_1-42 for AD diagnosis.

Potential revival of cholinesterase inhibitors as drugs in veterinary medicine

The cholinergic system is involved in the regulation of all organ systems and has acetylcholine (ACh) as almost its only neurotransmitter. Any substance is called cholinergic if it can alter the action of acetylcholine. Cholinesterases (ChEs) are enzymes that enable the hydrolysis of acetylcholine and in this way ensure homeostasis in cholinergic synapses. Cholinesterase inhibitors (ChEi) are a group of indirect-acting cholinergic agonists that influence the activity of the cholinergic system. Several compounds that can inhibit cholinesterases are of importance to veterinary medicine from pharmacological and toxicological perspective. The frequency of their use in veterinary medicine has fluctuated over the years and is now reduced to a minimum. They are mainly used in agriculture as pesticides, and some are rarely used as parasiticides for companion animals and livestock. In recent years, interest in the use of new cholinesterase inhibitors has increased since canine cognitive dysfunction (CCD) became a recognized and extensively studied disease. Similar to Alzheimer's disease (AD) in humans, CCD can be treated with cholinesterase inhibitors that cross the blood-brain barrier. In this review, the mammalian cholinergic system and the drugs that interact with cholinesterases are introduced. Cholinesterase inhibitors that can be used for the treatment of CCD are described in detail.

Experimental and Clinical Biomarkers for Progressive Evaluation of Neuropathology and Therapeutic Interventions for Acute and Chronic Neurological Disorders

This article describes commonly used experimental and clinical biomarkers of neuronal injury and neurodegeneration for the evaluation of neuropathology and monitoring of therapeutic interventions. Biomarkers are vital for diagnostics of brain disease and therapeutic monitoring. A biomarker can be objectively measured and evaluated as a proxy indicator for the pathophysiological process or response to therapeutic interventions. There are complex hurdles in understanding the molecular pathophysiology of neurological disorders and the ability to diagnose them at initial stages. Novel biomarkers for neurological diseases may surpass these issues, especially for early identification of disease risk. Validated biomarkers can measure the severity and progression of both acute neuronal injury and chronic neurological diseases such as epilepsy, migraine, Alzheimer's disease, Parkinson's disease, Huntington's disease, traumatic brain injury, amyotrophic lateral sclerosis, multiple sclerosis, and other brain diseases. Biomarkers are deployed to study progression and response to treatment, including noninvasive imaging tools for both acute and chronic brain conditions. Neuronal biomarkers are classified into four core subtypes: blood-based, immunohistochemical-based, neuroimaging-based, and electrophysiological biomarkers. Neuronal conditions have progressive stages, such as acute injury, inflammation, neurodegeneration, and neurogenesis, which can serve as indices of pathological status. Biomarkers are critical for the targeted identification of specific molecules, cells, tissues, or proteins that dramatically alter throughout the progression of brain conditions. There has been tremendous progress with biomarkers in acute conditions and chronic diseases affecting the central nervous system.

Interaction between ω-6 fatty acids intake and blood cadmium on the risk of low cognitive performance in older adults from National Health and Nutrition Examination Survey (NHANES) 2011-2014

Background

Identifying preventable diets and environmental exposure is essential to ensuring the health of the aging population. This study evaluated the interaction effect between blood cadmium and ω-6 fatty acids intake on low cognitive performance in Americans.

Method

The data of this cross-sectional study were obtained from the 2011–2012 and 2013–2014 National Health and Nutritional Examination Survey (NHANES). Cognitive performance was measured by the Consortium to Establish a Registry for Alzheimer’s Disease test, Animal Fluency Test, and Digit Symbol Substitution Test. Multivariate logistic regression models were used.

Results

A total of 1,918 individuals were included, with 467 (24.35%) low cognitive performance. Compared with participants with normal-level blood cadmium, those with high-level blood cadmium had a higher risk of low cognitive performance [odds ratio (OR) was 1.558 with 95% confidence interval (CI): 1.144–2.123]. Low-level ω-6 fatty acids intake was positively associated with low cognitive performance [OR = 1.633 (95%CI: 1.094–2.436)] compared with normal-level intake. Moreover, there was a significant interaction between low-level ω-6 fatty acids intake and high-level blood cadmium on the risk of low cognitive performance (relative excess risk due to interaction: 0.570, 95%CI: 0.208-0.932; the attributable proportion of interaction: 0.219, 95%CI: 0.102‐0.336; synergy index: 1.552, 95%CI: 1.189‐2.027).

Conclusions

There was a synergistic interaction between low-level ω-6 fatty acids intake and high-level blood cadmium on low cognitive performance. Low-level ω-6 fatty acids intake may amplify the adverse effects of long-term exposure to cadmium on cognitive performance. This may have a certain significance for the prevention of cognitive decline in the elderly.

Supplementary information

The online version contains supplementary material available at 10.1186/s12877-022-02988-7.

Chinese Herbal Extracts Exert Neuroprotective Effect in Alzheimer's Disease Mouse Through the Dopaminergic Synapse/Apoptosis Signaling Pathway

Background: Alzheimer's disease (AD) as an age-related, irreversible neurodegenerative disease, characterized by cognitive dysfunction, has become progressively serious with a global rise in life expectancy. As the failure of drug elaboration, considerable research effort has been devoted to developing therapeutic strategies for treating AD. TCM is gaining attention as a potential treatment for AD. Gastrodia elata Blume, Polygala tenuifolia Willd., Cistanche deserticola Ma, Rehmannia lutinosa (Gaertn.)DC., Acorus gramineus Aiton, and Curcuma longa L. (GPCRAC) are all well-known Chinese herbs with neuroprotective benefits and are widely used in traditional Chinese decoction for AD therapy. However, the efficacy and further mechanisms of GPCRAC extracts in AD experimental models are still unclear. The purpose of this study was to investigate the synergistic protective efficacy of GPCRAC extracts (composed of extracts from these six Chinese medicines), and the protein targets mediated by GPCRAC extracts in treating AD. Methods: Scopolamine-induced cognitive impairment mouse model was established to determine the neuroprotective effects of GPCRAC extracts in vivo, as shown by behavioral tests and cerebral cholinergic function assays. To identify the potential molecular mechanism of GPCRAC extracts against AD, label-free quantitative proteomics coupled with tandem mass spectrometry (LC-MS/MS) were performed. The integrated bioinformatics analysis was applied to screen the core differentially expressed proteins in vital canonical pathways. Critical altered proteins were validated by qPCR and Western blotting. Results: Administration of GPCRAC extracts significantly recovered scopolamine-induced cognitive impairment, as evidenced by the improved learning and memory ability, increased Ach content and ChAT activity, as well as decreased AchE activity in the hippocampus of mice. In total, 390 proteins with fold-change>1.2 or <0.83 and p < 0.05 were identified as significant differentially expressed proteins, of which 110 were significantly up-regulated and 25 were significantly down-regulated between control and model group. By mapping the significantly regulated proteins, we identified five hub proteins: PPP2CA, Gsk3β, PP3CC, PRKACA, and BCL-2 that were associated with dopaminergic synapse and apoptosis signaling pathway, respectively. Western blotting and QPCR demonstrate that the expression levels of these core proteins could be significantly improved by the administration of GPCRAC extracts. These pathways and some of the identified proteins are implicated in AD pathogenesis. Conclusion: Administration of GPCRAC extracts was effective on alleviating scopolamine-induced cognitive impairment, which might be through modulation of dopaminergic synapse and apoptosis signaling pathway. Consequently, our quantitative proteome data obtained from scopolamine-treated model mice successfully characterized AD-related biological alterations and proposed novel protein biomarkers for AD.