Vdac1 Downregulation Causes Mitochondrial Disintegration Leading to Hippocampal Neurodegeneration in Scopolamine-Induced Amnesic Mice

Targeting VDAC: A potential therapeutic approach for mitochondrial dysfunction in Alzheimer's disease

Mitochondrial dysfunction has been implicated in the pathogenesis of Alzheimer's disease, a neurodegenerative disorder characterized by progressive cognitive decline. Voltage-dependent anion channel (VDAC), a protein located in the outer mitochondrial membrane, plays a critical role in regulating mitochondrial function and cellular energy metabolism. Recent studies have identified VDAC as a potential therapeutic target for Alzheimer's disease. This article aims to provide an overview of the role of VDAC in mitochondrial dysfunction, its association with Alzheimer's disease, and the potential of targeting VDAC for developing novel therapeutic interventions. Understanding the involvement of VDAC in Alzheimer's disease may pave the way for the development of effective treatments that can restore mitochondrial function and halt disease progression.

Vitamin B12-folic acid supplementation improves memory by altering mitochondrial dynamics, dendritic arborization, and neurodegeneration in old and amnesic male mice

Memory impairment during aging and amnesia is attributed to compromised mitochondrial dynamics and mitophagy and other mitochondrial quality control mechanisms. Mitochondrial dynamics involves the continuous process of fission and fusion of mitochondria within a cell and is a fundamental mechanism for regulating mitochondrial quality and function. An extensive range of potential nutritional supplements has been shown to improve mitochondrial health, synaptic plasticity, and cognitive functions. Previous findings revealed that supplementation of vitamin B12-folic acid reduces locomotor deficits and mitochondrial abnormalities but enhances mitochondrial and neuronal health. The present study aims to explore the impact of combined vitamin B12-folic acid supplementation on mitochondrial dynamics, neuronal health, and memory decline in old age and scopolamine-induced amnesia, which remains elusive. The results demonstrated that supplementation led to a noteworthy increase in recognition and spatial memory and expression of memory-related protein BDNF in old and amnesic mice. Moreover, the decrease in the fragmented mitochondrial number was validated by the downregulation of mitochondrial fission p-Drp1 (S616) protein and the increase in elongated mitochondria by the upregulation of mitochondrial fusion Mfn2 protein. The increased spine density and dendritic arborization in old and amnesic mice upon supplementation were confirmed by the enhanced expression level of PSD95 and synaptophysin. Furthermore, supplementation reduced ROS production, inhibited Caspase-3 activation, mitigated neurodegeneration, and enhanced mitochondrial membrane potential, ATP production, Vdac1 expression, myelination, in old and amnesic mice. Collectively, our findings imply that combined supplementation of vitamin B12-folic acid improves mitochondrial dynamics and neuronal health, and leads to recovery of memory during old age and amnesia.

Mdivi-1 Rescues Memory Decline in Scopolamine-Induced Amnesic Male Mice by Ameliorating Mitochondrial Dynamics and Hippocampal Plasticity

Memory loss, often known as amnesia, is common in the elderly population and refers to forgetting facts and experiences. It is associated with increased mitochondrial fragmentation, though the contribution of mitochondrial dynamics in amnesia is poorly understood. Therefore, the present study is aimed at elucidating the role of Mdivi-1 in mitochondrial dynamics, hippocampal plasticity, and memory during scopolamine (SC)-induced amnesia. The findings imply that Mdivi-1 significantly increased the expression of Arc and BDNF proteins in the hippocampus of SC-induced amnesic mice, validating improved recognition and spatial memory. Moreover, an improved mitochondrial ultrastructure was attributed to a decline in the percentage of fragmented and spherical-shaped mitochondria after Mdivi-1 treatment in SC-induced mice. The significant downregulation of p-Drp1 (S616) protein and upregulation of Mfn2, LC3BI, and LC3BII proteins in Mdivi-1-treated SC-induced mice indicated a decline in fragmented mitochondrial number and healthy mitochondrial dynamics. Mdivi-1 treatment alleviated ROS production and Caspase-3 activity and elevated mitochondrial membrane potential, Vdac1 expression, ATP production, and myelination, resulting in reduced neurodegeneration in SC mice. Furthermore, the decline of pro-apoptotic protein cytochrome-c and increase of anti-apoptotic proteins Procaspase-9 and Bcl-2 in Mdivi-1-treated SC-induced mice suggested improved neuronal health. Mdivi-1 also increased the dendritic arborization and spine density, which was further corroborated by increased expression of synaptophysin and PSD95. In conclusion, the current study suggests that Mdivi-1 treatment improves mitochondrial ultrastructure and function through the regulation of mitochondrial dynamics. These changes further improve neuronal cell density, myelination, dendritic arborization, and spine density, decrease neurodegeneration, and improve recognition and spatial memory. Schematic presentation depicts that Mdivi-1 rescues memory decline in scopolamine-induced amnesic male mice by ameliorating mitochondrial dynamics and hippocampal plasticity.

Mitophagy: A promising therapeutic target for neuroprotection during ageing and age-related diseases

Mitochondria and mitochondria-mediated signalling pathways are known to control synaptic signalling, as well as long-lasting changes in neuronal structure and function. Mitochondrial impairment is linked to synaptic dysfunction in normal ageing and age-associated neurodegenerative ailments, including Parkinson's disease (PD) and Alzheimer's disease (AD). Both proteolysis and mitophagy perform a major role in neuroprotection, by maintaining a healthy mitochondrial population during ageing. Mitophagy, a highly evolutionarily conserved cellular process, helps in the clearance of damaged mitochondria and thereby maintains the mitochondrial and metabolic balance, energy supply, neuronal survival and neuronal health. Besides the maintenance of brain homeostasis, hippocampal mitophagy also helps in synapse formation, axonal development, dopamine release and long-term depression. In contrast, defective mitophagy contributes to ageing and age-related neurodegeneration by promoting the accumulation of damaged mitochondria leading to cellular dysfunction. Exercise, stress management, maintaining healthy mitochondrial dynamics and administering natural or synthetic pharmacological compounds are some of the strategies used for neuroprotection during ageing and age-related neurological diseases. The current review discusses the impact of defective mitophagy in ageing and age-associated neurodegenerative conditions, the underlying molecular pathways and potential therapies based on recently elucidated mitophagy-inducing strategies.

Dysfunctional mitochondrial processes contribute to energy perturbations in the brain and neuropsychiatric symptoms

Mitochondria are complex endosymbionts that evolved from primordial purple nonsulfur bacteria. The incorporation of bacteria-derived mitochondria facilitates a more efficient and effective production of energy than what could be achieved based on previous processes alone. In this case, endosymbiosis has resulted in the seamless coupling of cytochrome c oxidase and F-ATPase to maximize energy production. However, this mechanism also results in the generation of reactive oxygen species (ROS), a phenomenon that can have both positive and negative ramifications on the host. Recent studies have revealed that neuropsychiatric disorders have a pro-inflammatory component in which ROS is capable of initiating damage and cognitive malfunction. Our current understanding of cognition suggests that it is the product of a neuronal network that consumes a substantial amount of energy. Thus, alterations or perturbations of mitochondrial function may alter not only brain energy supply and metabolite generation, but also thought processes and behavior. Mitochondrial abnormalities and oxidative stress have been implicated in several well-known psychiatric disorders, including schizophrenia (SCZ) and bipolar disorder (BPD). As cognition is highly energy-dependent, we propose that the neuronal pathways underlying maladaptive cognitive processing and psychiatric symptoms are most likely dependent on mitochondrial function, and thus involve brain energy translocation and the accumulation of the byproducts of oxidative stress. We also hypothesize that neuropsychiatric symptoms (e.g., disrupted emotional processing) may represent the vestiges of an ancient masked evolutionary response that can be used by both hosts and pathogens to promote self-repair and proliferation via parasitic and/or symbiotic pathways.

Astrocytes Reduce Store-Operated Ca2+ Entry in Microglia under the Conditions of an Inflammatory Stimulus and Muscarinic Receptor Blockade

Inflammation and loss of cholinergic transmission are involved in neurodegenerative diseases, but possible interactions between them within neurons, astrocytes, and microglia have not yet been investigated. We aimed to compare store-operated Ca²⁺ entry (SOCE) in neurons, astrocytes, and microglia following cholinergic dysfunction in combination with (or without) an inflammatory stimulus and to investigate the effects of linalyl acetate (LA) on this process. We used the SH-SY5Y, U373, and BV2 cell lines related to neurons, astrocytes, and microglia, respectively. Scopolamine or lipopolysaccharide (LPS) was used to antagonize the muscarinic receptors or induce inflammatory responses, respectively. The concentration of intracellular Ca²⁺ was measured using Fura-2 AM. Treatment with scopolamine and LPS significantly increased SOCE in the neuron-like cells and microglia but not in the scopolamine-pretreated astrocytes. LA significantly reduced SOCE in the scopolamine-pretreated neuron-like cells and microglia exposed to LPS, which was partially inhibited by the Na⁺-K⁺ ATPase inhibitor ouabain and the Na⁺/Ca²⁺ exchanger (NCX) inhibitor Ni²⁺. Notably, SOCE was significantly reduced in the LPS plus scopolamine-pretreated cells mixed with astrocytes and microglia, with a two-fold increase in the applied number of astrocytes. LA may be useful in protecting neurons and microglia by reducing elevated SOCE that is induced by inflammatory responses and inhibiting the muscarinic receptors via Na⁺-K⁺ ATPase and the forward mode of NCX. Astrocytes may protect microglia by reducing increased SOCE under the conditions of inflammation and a muscarinic receptor blockade.

Pharmacokinetic improvement provided by microneedle patch in delivering bee venom, a case study in combating scopolamine-induced neurodegeneration in mouse model

Much research has shown Bee venom to be an effective neuroprotective agent. However, the usual transdermal injection of bee venom poses many pharmacokinetic disadvantages. Here, we compared the administration of bee venom via subcutaneous injection (SC) and via Microneedle patch (MN). Both administrated routes produce significant recovery effects, however: the MN significantly prolongs the bio-significant-and-yet-lower concentration of bee venom in mice bodies. In contrast, SC could produce only a short period of much higher bee venom levels in the blood and brain. We also see that due to the concentration-response-curve of bee venom (represented by melittin): mice bodies do not require much higher bee venom concentration (seen in the SC group) to produce a much more significant neuroprotective effect (than seen in those treated with the MN method). Therefore, a MN could maintain bee venom levels in mice bodies at lower-yet-more-efficient concentrations. This is important, as bee venom can cause more adverse effects and pain sensations, at higher concentrations. For the first time, we confirmed that the pharmacokinetic advantages of MN delivered bee venom also guarantee a holistic neuroprotection effect (which was shown by SC delivered bee venom in previous research). This was proven via the results of the water maze experiments for long-term learning memory assessment and protein analysis of key neuronal regulatory proteins: BDNF, p-CREB, iNOS, and mArhR 1. In conclusion, for situations where we ought to administrate drugs at a more downward amount, such as bee venom, MN can keep the therapeutic concentrations at a lower, yet interestingly, more-efficient level.

The Influence of Tyrosol-Enriched Rhodiola sachalinensis Extracts Bioconverted by the Mycelium of Bovista plumbe on Scopolamine-Induced Cognitive, Behavioral, and Physiological Responses in Mice

Alzheimer’s disease (AD) is an age-related neurodegenerative disorder characterized by cognitive deficits, which are accompanied by memory loss and cognitive disruption. Rhodiola sachalinensis (RSE) is a medicinal plant that has been used in northeastern Asia for various pharmacological activities. We attempted to carry out the bioconversion of RSE (Bio-RSE) using the mycelium of Bovista plumbe to obtain tyrosol-enriched Bio-RSE. The objective of this study was to investigate the effects of Bio-RSE on the activation of the cholinergic system and the inhibition of oxidative stress in mice with scopolamine (Sco)-induced memory impairment. Sco (1 mg/kg body weight, i.p.) impaired the mice’s performance on the Y-maze test, passive avoidance test, and water maze test. However, the number of abnormal behaviors was reduced in the groups supplemented with Bio-RSE. Bio-RSE treatment improved working memory and avoidance times against electronic shock, increased step-through latency, and reduced the time to reach the escape zone in the water maze test. Bio-RSE dramatically improved the cholinergic system by decreasing acetylcholinesterase activity and regulated oxidative stress by increasing antioxidant enzymes (superoxide dismutase (SOD) and catalase (CAT)). The reduction in nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling in the brain tissue due to scopolamine was restored by the administration of Bio-RSE. Bio-RSE also significantly decreased amyloid-beta 1–42 (Aβ1–42) and amyloid precursor protein (APP) expression. Moreover, the increased malondialdehyde (MDA) level and low total antioxidant capacity in Sco-treated mouse brains were reversed by Bio-RSE, and an increase in Nrf2 and HO-1 was also observed. In conclusion, Bio-RSE protected against Sco-induced cognitive impairment by activating Nrf2/HO-1 signaling and may be developed as a potential beneficial material for AD.

Alterations in hippocampal mitochondrial dynamics are associated with neurodegeneration and recognition memory decline in old male mice

Mitochondrial dynamics is a key process that modulates the ultrastructure, quality and function of mitochondria. It is disrupted in numerous major neurodegenerative disorders including Parkinson's, Alzheimer's and Huntington's disease. Mitochondrial dysfunction has been correlated with the loss of memory. Previous studies suggest the involvement of Vdac1 and Drp1 in outer mitochondrial membrane permeabilization and promotion of mitochondrial fragmentation through Drp1 phosphorylation at S616. However, alterations in mitochondrial dynamics with respect to aging, memory loss and neurodegeneration remain unexplored. Therefore, the present study focuses on the involvement of mitochondrial dynamics in neurodegeneration and recognition memory decline during aging. The recognition memory decline was validated by the novel object recognition test and measurement of hippocampal Arc protein level during aging. The ultrastructure analysis revealed a decline in mitochondrial length and area, while an increase in the number of fragmented, round and disrupted mitochondria in the hippocampus during aging. Disruption was also evident in mitochondrial cristae and membrane with advancing age. The change in mitochondrial morphology was corroborated by an increase in the expression of phospho-Drp1 (S616) and Cyt-c proteins but decline in Mfn2, LC3B, Vdac1, Bcl-XL and Bcl-2 proteins in the hippocampus during aging. Taken together, our findings reveal that an increase in the expression of phospho-Drp1 (S616) and decrease in Mfn2 and LC3B proteins in the hippocampus bring about a reduction in mitochondrial length and area, and rise in mitochondrial fragmentation leading to reduced neuronal cell density, increased neurodegeneration and recognition memory decline in old male mice. Diagram depicts the increase in hippocampal mitochondrial fragmentation during aging of mice. Increased mitochondrial fragmentation causes distorted mitochondrial function such as decrease in ATP/ADP transportation due to decrease in Vdac1 protein level and increase in oxidative damage. These alterations result in hippocampal neurodegeneration and consequently impairment in recognition memory during aging.

Voltage Dependent Anion Channel 3 (VDAC3) protects mitochondria from oxidative stress

Unraveling the role of VDAC3 within living cells is challenging and still requires a definitive answer. Unlike VDAC1 and VDAC2, the outer mitochondrial membrane porin 3 exhibits unique biophysical features that suggest unknown cellular functions. Electrophysiological studies on VDAC3 carrying selective cysteine mutations and mass spectrometry data about the redox state of such sulfur containing amino acids are consistent with a putative involvement of isoform 3 in mitochondrial ROS homeostasis. Here, we thoroughly examined this issue and provided for the first time direct evidence of the role of VDAC3 in cellular response to oxidative stress. Depletion of isoform 3 but not isoform 1 significantly exacerbated the cytotoxicity of redox cyclers such as menadione and paraquat, and respiratory complex I inhibitors like rotenone, promoting uncontrolled accumulation of mitochondrial free radicals. High-resolution respirometry of transiently transfected HAP1-ΔVDAC3 cells expressing the wild type or the cysteine-null mutant VDAC3 protein, unequivocally confirmed that VDAC3 cysteines are indispensable for protein ability to counteract ROS-induced oxidative stress.

Chalcone-Derived Nrf2 Activator Protects Cognitive Function via Maintaining Neuronal Redox Status

NF-E2-related factor 2 (Nrf2), the key transcription regulator of phase II enzymes, has been considered beneficial for neuronal protection. We previously designed a novel chalcone analog, 1-(2,3,4-trimethoxyphenyl)-2-(3,4,5-trimethoxyphenyl)-acrylketone (Tak), that could specifically activate Nrf2 in vitro. Here, we report that Tak confers significant hippocampal neuronal protection both in vitro and in vivo. Treatment with Tak has no significant toxicity on cultured neuronal cells. Instead, Tak increases cellular ATP production by increasing mitochondrial function and decreases the levels of reactive oxygen species by activating Nrf2-mediated phase II enzyme expression. Tak pretreatment prevents glutamate-induced excitotoxic neuronal death accompanied by suppressed mitochondrial respiration, increased superoxide production, and activation of apoptosis. Further investigation indicates that the protective effect of Tak is mediated by the Akt signaling pathway. Meanwhile, Tak administration in mice can sufficiently abrogate scopolamine-induced cognitive impairment via decreasing hippocampal oxidative stress. In addition, consistent benefits are also observed in an energy stress mouse model under a high-fat diet, as the administration of Tak remarkably increases Akt signaling-mediated antioxidative enzyme expression and prevents hippocampal neuronal apoptosis without significant effect on the mouse metabolic status. Overall, our study demonstrates that Tak protects cognitive function by Akt-mediated Nrf2 activation to maintain redox status both vivo and in vitro, suggesting that Tak is a promising pharmacological candidate for the treatment of oxidative neuronal diseases.

Depletion of a Toxoplasma porin leads to defects in mitochondrial morphology and contacts with the endoplasmic reticulum

The voltage-dependent anion channel (VDAC) is a ubiquitous channel in the outer membrane of the mitochondrion with multiple roles in protein, metabolite and small molecule transport. In mammalian cells, VDAC protein, as part of a larger complex including the inositol triphosphate receptor, has been shown to have a role in mediating contacts between the mitochondria and endoplasmic reticulum (ER). We identify VDAC of the pathogenic apicomplexan Toxoplasma gondii and demonstrate its importance for parasite growth. We show that VDAC is involved in protein import and metabolite transfer to mitochondria. Further, depletion of VDAC resulted in significant morphological changes in the mitochondrion and ER, suggesting a role in mediating contacts between these organelles in T. gondii.

This article has an associated First Person interview with the first author of the paper.

Summary: Depletion of the Toxoplasma voltage-dependent anion channel highlights the importance of endoplasmic reticulum–mitochondria membrane contact sites in maintaining organelle morphology.

Investigation of alpha-lipoic acid effect on memory impairment considering strain-dependent differences in mice

AIMS

Memory impairment is regarded as one of the most challenging neurological disorders. The present study aimed to investigate behavioral and biochemical differences among similar mouse strains following Scopolamine (SCO) exposure as a widespread memory disturbing agent, and a supremely potent antioxidant, alpha-lipoic acid (ALA).

MATERIALS AND METHODS

Three sets of mouse strains (i.e. SW, NMRI, and NIH mice) were subjected to 2 mg/kg intraperitoneal SCO and/or 50 mg/kg ALA 30 min before each Morris Water Maze (MWM) trial for five consecutive days. Upon completion of the trials, the hippocampal region of the animals was dissected for histopathological and biochemical analyses.

KEY FINDINGS

The results exhibited significant impairments caused by SCO in behavioral tests, including probe test, escape latency, and distance traveled in two strains of NMRI and NIH. Nevertheless, at swimming speed, SCO had no meaningful effect on SW and NIH strains. The level of oxidative stress parameters including MDA, ROS, and SOD increased, FRAP and TTM levels related to the hippocampus decreased. There was also a significant increase in hippocampal acetylcholinesterase levels, ADP/ATP ratio, p-NFkB, and Cyt-c. Conversely, ALA administration resulted in a significant improvement in SCO-induced spatial learning and memory impairments only in the SW and NIH mice, which was associated with a significant reduction in hippocampal AChE activity, ADP/ATP ratio, ROS and MDA levels, and SOD activity.

SIGNIFICANCE

In addition of highlighting the efficacious role of ALA in cognitive functions, the findings of this study signified the behavioral dissimilarities among similar animal strains in case of different chemical exposures.

Ischemia Injury induces mPTP opening by reducing Sirt3

Mitochondrial permeability transition pore (mPTP) opening is critical to mitochondrial apoptosis during ischemic injury. Sirtuin 3 (Sirt3) is a mitochondrial deacetylase known to play a major role in stress resistance and cell death. Our previous studies have shown that Sirt3 activates superoxide dismutase 2 and forkhead box O3a to reduce cellular reactive oxygen species. However, it is unclear the interaction between Sirt3 and mPTP and the roles they play in ischemic stroke. We used the middle cerebral artery occlusion (MCAO) model, a mouse model of stroke, to examine Sirt3 and mPTP-related protein levels. We then applied lentivirus packaged Sirt3 overexpression in HT22 cells, a mouse hippocampal neuronal cell line, to investigate the underlying mechanism. We found Sirt3 protein level was decreased in the penumbra area in MCAO mice, along with an increase in mPTP related proteins, namely voltage-dependent anion channel 1 (VDAC1) and adenine nucleotide translocator 1 (ANT1). Sirt3 overexpression suppressed the increase in VDAC1, ANT1 and cleaved caspase 3 that were induced by the serum and glucose deprivation (SGD) condition. Our studies suggest that ischemic injury induced mPTP opening and apoptosis by reducing Sirt3. It helps to identify new therapeutic targets for ischemic stroke.

Sodium tanshinone IIA sulfonate protects against Aβ-induced cell toxicity through regulating Aβ process

Sodium tanshinone IIA sulfonate (STS) has been reported to prevent Alzheimer's disease (AD). However, the mechanism is still unknown. In this study, two in vitro models, Aβ-treated SH-SY5Y cells and SH-SY5Y human neuroblastoma cells transfected with APPsw (SH-SY5Y-APPsw cells), were employed to investigate the neuroprotective of STS. The results revealed that pretreatment with STS (1, 10 and 100 µmol/L) for 24 hours could protect against Aβ (10 µmol/L)-induced cell toxicity in a dose-dependent manner in the SH-SY5Y cells. Sodium tanshinone IIA sulfonate decreased the concentrations of reactive oxygen species, malondialdehyde, NO and iNOS, while increased the activities of superoxide dismutase and glutathione peroxidase in the SH-SY5Y cells. Sodium tanshinone IIA sulfonate decreased the levels of inflammatory factors (IL-1β, IL-6 and TNF-α) in the SH-SY5Y cells. In addition, Western blot results revealed that the expressions of neprilysin and insulin-degrading enzyme were up-regulated in the SH-SY5Y cells after STS treatment. Furthermore, ELISA and Western blot results showed that STS could decrease the levels of Aβ. ELISA and qPCR results indicated that STS could increase α-secretase (ADAM10) activity and decrease β-secretase (BACE1) activity. In conclusion, STS could protect against Aβ-induced cell damage by modulating Aβ degration and generation. Sodium tanshinone IIA sulfonate could be a promising candidate for AD treatment.

FA-97, a New Synthetic Caffeic Acid Phenethyl Ester Derivative, Protects against Oxidative Stress-Mediated Neuronal Cell Apoptosis and Scopolamine-Induced Cognitive Impairment by Activating Nrf2/HO-1 Signaling

Alzheimer's disease (AD) is an age-related neurodegenerative disorder with cognitive deficits, which is becoming markedly more common in the world. Currently, the exact cause of AD is still unclear, and no curative therapy is available for preventing or mitigating the disease progression. Caffeic acid phenethyl ester (CAPE), a natural phenolic compound derived from honeybee hive propolis, has been reported as a potential therapeutic agent against AD, while its application is limited due to the low water solubility and poor bioavailability. Here, caffeic acid phenethyl ester 4-O-glucoside (FA-97) is synthesized. We validate that FA-97 attenuates H₂O₂-induced apoptosis in SH-SY5Y and PC12 cells and suppresses H₂O₂-induced oxidative stress by inhibiting the ROS level, malondialdehyde (MDA) level, and protein carbonylation level, as well as induces cellular glutathione (GSH) and superoxide dismutase (SOD). Mechanistically, FA-97 promotes the nuclear translocation and transcriptional activity of Nrf2 associated with the upregulated expression of HO-1 and NQO-1. The prime importance of Nrf2 activation in the neuroprotective and antioxidant effects of FA-97 is verified by Nrf2 siRNA transfection. In addition, FA-97 prevents scopolamine- (SCOP-) induced learning and memory impairments in vivo via reducing neuronal apoptosis and protecting against cholinergic system dysfunction in the hippocampus and cortex. Moreover, the increased MDA level and low total antioxidant capacity in SCOP-treated mouse brains are reversed by FA-97, with the increased expression of HO-1, NQO-1, and nuclear Nrf2. In conclusion, FA-97 protects against oxidative stress-mediated neuronal cell apoptosis and SCOP-induced cognitive impairment by activating Nrf2/HO-1 signaling, which might be developed as a therapeutic drug for AD.

Cerebrospinal Fluid-Derived Microvesicles From Sleeping Sickness Patients Alter Protein Expression in Human Astrocytes

Human African trypanosomiasis (HAT) caused by the extracellular protozoon Trypanosoma brucei, is a neglected tropical disease affecting the poorest communities in sub-Saharan Africa. HAT progresses from a hemolymphatic first stage (S1) to a meningo-encephalitic late stage (S2) when parasites reach the central nervous system (CNS), although the existence of an intermediate stage (Int.) has also been proposed. The pathophysiological mechanisms associated with the development of S2 encephalopathy are yet to be fully elucidated. Here we hypothesized that HAT progression toward S2 might be accompanied by an increased release of microvesicles (MVs), sub-micron elements (0.1–1 μm) involved in inflammatory processes and in the determination of the outcome of infections. We studied the morphology of MVs isolated from HAT cerebrospinal fluid (CSF) by transmission electron microscopy (TEM) and used flow cytometry to show that total-MVs and leukocyte derived-CD45⁺ MVs are significantly increased in concentration in S2 patients' CSF compared to S1 and Int. samples (n = 12 per group). To assess potential biological properties of these MVs, immortalized human astrocytes were exposed, in vitro, to MVs enriched from S1, Int. or S2 CSF. Data-independent acquisition mass spectrometry analyses showed that S2 MVs induced, compared to Int. or S1 MVs, a strong proteome modulation in astrocytes that resembled the one produced by IFN-γ, a key molecule in HAT pathogenesis. Our results indicate that HAT S2 CSF harbors MVs potentially involved in the mechanisms of pathology associated with HAT late stage. Such vesicles might thus represent a new player to consider in future functional studies.

Studies of the Anti-amnesic Effects and Mechanisms of Single and Combined Use of Donepezil and Ginkgo Ketoester Tablet on Scopolamine-Induced Memory Impairment in Mice

Ginkgo ketoester tablets (GT) and donepezil were a clinically used combination for the treatment of Alzheimer's disease (AD). The aim of the study was undertaken to investigate the antiamnesic effects of the two drugs alone and in combination through in vivo models of the Morris water maze along with in vitro antioxidants, acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). The potential mechanisms were speculated by the activities of acetylcholine (ACh), AChE, superoxide dismutase (SOD), and malondialdehyde (MDA) and the protein expression of brain-derived neurotrophic factor (BDNF) and tyrosine protein kinase B (TrkB). The combination group showed a concentration-dependent inhibition of cholinesterase and antioxidation. As far as its mechanism was concerned, the combination of two drugs exerted excellent effects on oxidative stress, cholinergic pathway damage, and inactivation of the BDNF-TrkB signaling pathway. Additionally, to elucidate the binding mechanism of GT active ingredients into the structure of AChE, the results of molecular docking studies indicated that hydrogen and/or hydrophobic bonds might play an important role in their binding process. Thus, the combination of drugs could treat AD perfectly and further verify the scientific rationality of clinical medication.