Nicotine Enantioselectively Targets Myeloid Differentiation Protein 2 and Inhibits the Toll-like Receptor 4 Signaling.

Psychoactive substances, including morphine and methamphetamine, have been shown to interact with the classic innate immune receptor Toll-like receptor 4 (TLR4) and its partner protein myeloid differentiation protein 2 (MD2) in a nonenantioselective manner. (-)-Nicotine, the primary alkaloid in tobacco and a key component of highly addictive cigarettes, targets the TLR4/MD2, influencing TLR4 signaling pathways. Existing as two enantiomers, the stereoselective recognition of nicotine by TLR4/MD2 in the context of the innate immune response remains unclear. In this study, we synthesized (+)-nicotine and investigated its effects alongside (-)-nicotine on lipopolysaccharide (LPS)-induced TLR4 signaling. (-)-Nicotine dose-dependently inhibited proinflammatory factors such as tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), and cyclooxygenase-2 (COX-2). In contrast, (+)-nicotine showed no such inhibitory effects. Molecular dynamics simulations revealed that (-)-nicotine exhibited a stronger affinity with the TLR4 coreceptor MD2 than (+)-nicotine. Additionally, in silico simulations revealed that both nicotine enantiomers initially attach to the entrance of the MD2 cavity, creating a metastable state before they fully enter the cavity. In the metastable state, (-)-nicotine established more stable interactions with the surrounding residues at the entrance of the MD2 cavity compared to those of (+)-nicotine. This highlights the crucial role of the MD2 cavity entrance in the chiral recognition of nicotine. These findings provide valuable insights into the distinct interactions between nicotine enantiomers and the TLR4 coreceptor MD2, underscoring the enantioselective effect of nicotine on modulating TLR4 signaling.

Dissecting the chiral recognition of TLR4/MD2 with Neoseptin-3 enantiomers by molecular dynamics simulations.

Toll-like receptor 4 (TLR4) is a pivotal innate immune recognition receptor that regulates intricate signaling pathways within the immune system. Neoseptin-3 (Neo-3), a recently identified small-molecule agonist for mouse TLR4/MD2, exhibits chiral recognition properties. Specifically, the L-enantiomer of Neo-3 (L-Neo-3) effectively activates the TLR4 signaling pathway, while D-Neo-3 fails to induce TLR4 activation. However, the underlying mechanism by which TLR4 enantioselectively recognizes Neo-3 enantiomers remains poorly understood. In this study, in silico simulations were performed to investigate the mechanism of chiral recognition of Neo-3 enantiomers by TLR4/MD2. Two L-Neo-3 molecules stably resided within the cavity of MD2 as a dimer, and the L-Neo-3 binding stabilized the (TLR4/MD2)2 dimerization state. However, the strong electrostatic repulsion between the hydrogen atoms on the chiral carbon of D-Neo-3 molecules caused the relative positions of two D-Neo-3 molecules to continuously shift during the simulation process, thus preventing the formation of D-Neo-3 dimer as well as their stable interactions with the surrounding residues in (TLR4/MD2)2. Considering that L-Neo-3 could not sustain a stable dimeric state in the bulk aqueous environment, it is unlikely that L-Neo-3 entered the cavity of MD2 as a dimeric unit. Umbrella sampling simulations revealed that the second L-Neo-3 molecule entering the cavity of MD2 exhibited a lower binding energy (-25.75 kcal mol-1) than that of the first L-Neo-3 molecule (-14.31 kcal mol-1). These results imply that two L-Neo-3 molecules enter the cavity of MD2 sequentially, with the binding of the first L-Neo-3 molecule facilitating the entry of the second one. This study dissects the binding process of Neo-3 enantiomers, offering a comprehensive understanding of the atomic-level mechanism underlying TLR4's chiral recognition of Neo-3 molecules.

Dissecting the species-specific recognition of Neoseptin 3 by TLR4/MD2 via molecular dynamics simulations.

Toll-like receptor 4 (TLR4) is crucial in the innate immune response with species-specific recognition. As a novel small-molecule agonist for mouse TLR4/MD2, Neoseptin 3 fails to activate human TLR4/MD2, while the underlying mechanism is unclear. Herein, molecular dynamics simulations were performed to investigate the species-specific molecular recognition of Neoseptin 3. Lipid A, a classic TLR4 agonist showing no apparent species-specific sensing by TLR4/MD2, was also investigated for comparison. Neoseptin 3 and lipid A showed similar binding patterns with mouse TLR4/MD2. Although the binding free energies of Neoseptin 3 interacting with TLR4/MD2 from mouse and human species were similar, protein-ligand interactions and the details of the dimerization interface were substantially different between Neoseptin 3-bound mouse and human heterotetramers at the atomic level. Neoseptin 3 binding made human (TLR4/MD2)2 more flexible than human (TLR4/MD2/Lipid A)2, especially at the TLR4 C-terminus and MD2, which drives human (TLR4/MD2)2 fluctuating away from the active conformation. In contrast to mouse (TLR4/MD2/2*Neoseptin 3)2 and mouse/human (TLR4/MD2/Lipid A)2 systems, Neoseptin 3 binding to human TLR4/MD2 led to the separating trend of the C-terminus of TLR4. Furthermore, the protein-protein interactions at the dimerization interface between TLR4 and the neighboring MD2 in the human (TLR4/MD2/2*Neoseptin 3)2 system were much weaker than those of the lipid A-bound human TLR4/MD2 heterotetramer. These results explained the inability of Neoseptin 3 to activate human TLR4 signaling and accounted for the species-specific activation of TLR4/MD2, which provides insight for transforming Neoseptin 3 as a human TLR4 agonist.

Hydrogen-Bonded Organic Framework (HOF)-Based Single-Neural Stem Cell Encapsulation and Transplantation to Remodel Impaired Neural Networks.

Herein we present a new way to encapsulate neural stem cells (NSCs) by using hydrogen-bonded organic frameworks (HOFs) to overcome the common causes of low therapeutic efficacy during NSC transplantation: 1) loss of fundamental stem cell properties, "stemness", before transplantation, 2) cytomembrane damage during transplantation, and 3) apoptosis due to oxidative stress after transplantation. Porous carbon nanospheres (PCNs) are doped into the HOF shell during the process of mineralization to endow the cellular exoskeletons with hierarchical hydrogen bonds, and the ability to resist oxidative stress due to the catalase and superoxide dismutase-like activities of PCN. Under NIR-II irradiation, thermal-responsive hydrogen bonds dissociate to release NSCs. Stereotactic transplanting encapsulated NSC into the brain of an Alzheimer's disease (AD) mouse model further verifies that our design can enhance NSC viability, promote neurogenesis, and ameliorate cognitive impairment. As the first example of using HOFs to encapsulate NSCs, this work may inspire the design of HOF-based exoskeletons to ameliorate neurogenesis and cognitive behavioral symptoms associated with AD.

Bis(ethylmaltolato)oxidovanadium (IV) alleviates neuronal apoptosis through regulating peroxisome proliferator-activated receptor γ in a triple transgenic animal model of Alzheimer's disease.

Endoplasmic reticulum stress (ER stress) plays a critical role in neuronal apoptosis along with the aggravation of Alzheimer's disease (AD). Nuclear receptor peroxisome proliferator-activated receptor gamma (PPARγ) is a ligand-activated transcription factor that is involved in regulating ER stress in Alzheimer's disease (AD), therefore, this protein could be a promising therapeutic target for AD. Vanadium compounds, such as vanadyl acetylacetonate, sodium metavanadate and bis(maltolato)oxovanadium, are well-known as puissant PPARγ modulators. Thus, we are curious whether bis(ethylmaltolato)oxidovanadium (IV) (BEOV) can ameliorate ER stress and subsequent neuronal apoptosis by regulating PPARγ in AD models. To this end, we determined the effect of BEOV on behavioral performance, ER stress and neuronal apoptosis in the triple transgenic mouse AD model (3×Tg-AD). Our results showed that BEOV improved cognitive abilities and reduced the ER stress- and apoptosis-associated proteins in the brains of 3×Tg-AD mice. In vitro administration of BEOV in primary hippocampal neurons and N2asw cells achieved similar results in repressing ER stress. In addition, cotreatment with GW9662 (an antagonist of PPARγ) effectively blocked these neuroprotective effects of BEOV, which provided strong evidence that PPARγ-dependent signaling plays a key role in protecting against ER stress and neuronal apoptosis in AD. In conclusion, our data demonstrated that BEOV alleviated neuronal apoptosis triggered by ER stress by regulating PPARγ in a 3×Tg-AD model.

Self-Protecting Biomimetic Nanozyme for Selective and Synergistic Clearance of Peripheral Amyloid-ß in an Alzheimer's Disease Model.

Clearance of peripheral amyloid-ß (Aß) has been demonstrated to be promising for overcoming the blood-brain barrier (BBB) hurdle to eliminate brain-derived Aß associated with Alzheimer's disease (AD). Even so, current developed therapeutic assays for clearance of peripheral Aß are still facing challenges on how to avoid interference of certain biological molecules and prevent triggering the activation of immune responses and blood clotting. Here, a biomimetic nanozyme (CuxO@EM-K) with augmented protein adsorption resistance, minimized immunogenicity, and enhanced biocompatibility is designed and synthesized. The CuxO@EM-K is made of CuxO nanozyme wrapped with modified 3xTg-AD mouse erythrocyte membrane with Aß-targeting pentapeptide KLVFF. KLVFF serves as Aß-specific ligand that works together with erythrocyte membrane to selectively capture Aß in the blood. Meanwhile, the erythrocyte membrane coating prevents protein coronas formation and thus retains Aß-targeting ability of CuxO@EM-K in biological fluids. More importantly, the CuxO core with multiple antioxidant enzyme-like activities stabilizes the outer erythrocyte membrane and simultaneously mitigates Aß-induced membrane oxidative damage, which enables the extended systemic circulation indispensable for adsorbing Aß. In vivo studies demonstrate that CuxO@EM-K not only reduces Aß burden in the blood and brain but also ameliorates memory deficits in the widely used 3xTg-AD mouse model. Moreover, CuxO@EM-K shows no apparent toxicity in 3xTg-AD mice. Overall, this work provides an example for developing biocompatible and synergistic clearance of peripheral Aß associated with AD.

Loss of MsrB1 perturbs spatial learning and long-term potentiation/long-term depression in mice.

MsrB1 belongs to the methionine sulfoxide reductase family, it is also known as selenoprotein R for the sake of possessing a selenocysteine residue. It has been reported that MsrB1 could interact with actin, TRPM6, clusterin, and amyloid-beta in vitro. Thus, we presumed that MsrB1 may play an important role in central nervous system. To examine whether MsrB1 knockout has any effects on brain development or learning behavior, we carried out histological study on brains of MsrB1 deficient mice, and further tested spatial learning ability and long-term synaptic plasticity of these mice by using Morris water maze and electrophysiological methods. It was observed that loss of MsrB1 did not perturb the overall development of central nervous system except for the astrogliosis in hippocampus, however, it led mice to be incapable in spatial learning and severe impairments in LTP/LTD expression in CA1 of brain slices, along with the down-regulation of the synaptic proteins including PSD95, SYP, GluN2A and GluN2B, as well as the dramatic decrease of CaMKIIs phosphorylation at 286(287) compared with wild type mice. Taken together, these results suggest that MsrB1 is essential for mice spatial learning and LTP/LTD induction, and the MsrB1 related redox homeostasis may be involved in regulating the phosphorylation of CaMKIIs.

Zn2+ Aggravates Tau Aggregation and Neurotoxicity.

Alzheimer's disease (AD) is a neurodegenerative disease with high morbidity that has received extensive attention. However, its pathogenesis has not yet been completely elucidated. It is mainly related to ß-amyloid protein deposition, the hyperphosphorylation of tau protein, and the loss of neurons. The main function of tau is to assemble tubulin into stable microtubules. Under pathological conditions, tau is hyperphosphorylated, which is the major component of neurofibrillary tangles (NFT) in AD. There is considerable evidence showing that the dyshomeostasis of Zn2+ is closely related to the development of AD. Herein, by using the third repeat unit of the microtubule-binding domain of tau (tau-R3), we investigated the effect of Zn2+ on the aggregation and neurotoxicity of tau. Experimental results showed that tau-R3 probably bound Zn2+ via its Cys residue with moderate affinity (association constant (Ka) = 6.82 ± 0.29 × 104 M-1). Zn2+ accelerated tau-R3 aggregation and promoted tau-R3 to form short fibrils and oligomers. Compared with tau-R3, Zn2+-tau-R3 aggregates were more toxic to Neuro-2A (N2A) cells and induced N2A cells to produce higher levels of reactive oxygen species (ROS). The dendrites and axons of Zn2+-tau-R3-treated neurons became fewer and shorter, resulting in a large number of neuronal deaths. In addition, both tau-R3 and Zn2+-tau-R3 aggregates were found to be taken up by N2A cells, and more Zn2+-tau-R3 entered the cells compared with tau-R3. Our data demonstrated that Zn2+ can aggravate tau-R3 aggregation and neurotoxicity, providing clues to understand the relationship between Zn2+ dyshomeostasis and the etiology of Alzheimer's disease.

Integrative Chemical Proteomics-Metabolomics Approach Reveals Acaca/Acacb as Direct Molecular Targets of PFOA.

Identification of the direct molecular targets of environmental pollutants is of great importance for toxicity mechanism studies. Despite numerous studies have been conducted to investigate the toxicity mechanism of perfluorinated compounds (PFCs), their direct-binding protein targets which trigger downstream toxicity effects remain largely unknown. Herein, we present a systematic chemical proteomic study to profile the target proteins of PFCs by taking PFOA as a representative. Considering its electrophilicity, PFOA could preferentially bind to reactive cysteine-containing proteins. Therefore, two complementary cysteine-targeting probes, iodoacetamide alkyne (IAA) and ethynyl benziodoxolone azide (EBX), were selected to enrich the putative target proteins in the absence or presence of PFOA. Quantitative proteomic analysis of the enriched proteins identified Acaca and Acacb as novel target proteins of PFOA. We then applied parallel reaction monitoring (PRM)-based targeted proteomics study combined with thermal shift assay-based chemical proteomics to verify Acaca and Acacb as bona fide binding targets. These findings afford a plausible explanation for the PFOA-induced liver toxicity, especially regarding abnormal fatty acid metabolism that was validated by targeted metabolomics analysis. The present study documents an integrative chemical proteomics-metabolomics platform that facilitates the authentic identification of proteins that are targeted by small molecules and its potential to be applied for toxicity mechanism studies of environmental pollutants.

Ebselen ameliorates ß-amyloid pathology, tau pathology, and cognitive impairment in triple-transgenic Alzheimer's disease mice.

Alzheimer's disease (AD) is a progressive neurodegenerative disease which is clinically characterized by memory loss and cognitive decline caused by protein misfolding and aggregation. Imbalance between free radicals and the antioxidant system is a prominent and early feature in the neuropathology of AD. Selenium (Se), a vital trace element with excellent antioxidant potential, is preferentially retained in the brain in Se-limited conditions and has been reported to provide neuroprotection through resisting oxidative damage. In this paper, we studied for the first time the potential of Ebselen, a lipid-soluble selenium compound with GPx-like activity, in the treatment of cognitive dysfunction and neuropathology of triple-transgenic AD (3 × Tg-AD) mice, AD model cell, and primary culture. We demonstrated that Ebselen inhibited oxidative stress in both AD model cells and mouse brains with increasing GPx and SOD activities and meanwhile reduced p38 mitogen-activated protein kinases activities. By decreasing the expression of amyloid precursor protein and ß-secretase, Ebselen reduced the levels of Aß in AD neurons and mouse brains, especially the most toxic oligomeric form. Besides, mislocation of phosphorylated tau in neurons and phosphorylation levels of tau protein at Thr231, Ser396, and Ser404 residues were also inhibited by Ebselen, probably by its regulatory roles in glycogen synthase kinase 3ß and protein phosphatase 2A activity. In addition, Ebselen mitigated the decrease of synaptic proteins including synaptophysin and postsynaptic density protein 95 in AD model cells and neurons. Consequently, the spatial learning and memory of 3 × Tg-AD mice were significantly improved upon Ebselen treatment. This study provides a potential novel therapeutic approach for the prevention of AD.

Inhibitory effect of selenoprotein P on Cu(+)/Cu(2+)-induced Aß42 aggregation and toxicity.

It has been suggested that the aggregation and cytotoxicity of amyloid-ß (Aß) peptide with transition-metal ions in neuronal cells is involved in the progression of Alzheimer's disease (AD). Selenoproteins are a group of special proteins that contain the 21st amino acid selenocysteine in their sequence, and they are found to be involved in the onset and progression of AD. Here, we report that the histidine-rich domain of selenoprotein P (SelP-H) is capable of binding Cu ions in both oxidation states of Cu(+) and Cu(2+) with high affinity and of modulating Cu(+) and Cu(2+)-mediated Aß aggregation, reactive oxygen species (ROS) production, and neurotoxicity. SelP-H was found to coordinate 1 and 2 mol equiv of Cu(+) and Cu(2+) with sub-picomolar and nanomolar affinities, respectively. Cu(+)/Cu(2+) binding to Aß42 inhibited the fibrillization of Aß42 but induced it to form amorphous aggregates, which could be significantly restored by SelP-H, as observed by thioflavin T fluorescence and transmission electron microscopy. Interestingly, SelP-H inhibited Cu(+)/Cu(2+)-Aß42-induced neurotoxicity and the intracellular ROS production in living cells. These studies suggest that SelP may play certain roles in regulating redox balance as well as metal homeostasis.

Inhibitory act of selenoprotein P on Cu(+)/Cu(2+)-induced tau aggregation and neurotoxicity.

Alzheimer's disease (AD) is a neurodegenerative disorder that is characterized by peptide and protein misfolding and aggregation, in part due to the presence of excess metal ions such as copper. Aggregation and cytotoxicity of amyloid-ß (Aß) peptide with copper ion have been investigated extensively; however, the effects of metalation on tau are less known. Here, we presented the effects of Cu(+) and Cu(2+) on aggregation and neurotoxicity of the second repeat unit of the microtubule-binding domain of tau (tau-R2). Tau-R2 was demonstrated to bind 0.44 Cu(2+) and 0.34 Cu(+) per monomer with dissociation constants of 1.1 nM and 0.2 pM, respectively. Copper in both oxidation states stimulated the aggregation, ROS production, and neuronal cytotoxicity of tau-R2. We showed that copper-associated tau-R2 aggregates, decreased protein levels of microtubule-associated protein 2 (MAP-2), and synaptophysin in the primarily cultured cortical neurons, reduced mitochondrial density and mobility in the axon and, as a consequence, impaired the growth and probably also the function of neurons. Previously, we reported that the His-rich domain of selenoprotein P (SelP-H) inhibited metal-induced aggregation and toxicity of Aß, due to its metal chelation ability. Here we demonstrated that SelP-H not only inhibited copper-mediated tau aggregation but also interfered with the ongoing aggregation and reversed the already formed aggregates. More intriguing, SelP-H significantly attenuated Cu(2+)/Cu(+)-tau-R2-induced intracellular ROS production and the impairments of synapse and mitochondrial movement in neurons. This work implies that the surface-exposed His-rich domain of SelP makes it capable of modulating Cu(+)/Cu(2+)-mediated aggregation and neurotoxicity of both Aß and tau and may play important roles in the prevention of AD progression.

Direct interaction between selenoprotein P and tubulin.

Selenium (Se), an essential trace element for human health, mainly exerts its biological function via selenoproteins. Among the 25 selenoproteins identified in human, selenoprotein P (SelP) is the only one that contains multiple selenocysteines (Sec) in the sequence, and has been suggested to function as a Se transporter. Upon feeding a selenium-deficient diet, mice lacking SelP develop severe neurological dysfunction and exhibit widespread brainstem neurodegeneration, indicating an important role of SelP in normal brain function. To further elucidate the function of SelP in the brain, SelP was screened by the yeast two-hybrid system from a human fetal brain cDNA library for interactive proteins. Our results demonstrated that SelP interacts with tubulin, alpha 1a (TUBA1A). The interaction between SelP and tubulin was verified by fluorescence resonance energy transfer (FRET) and co-immunoprecipitation (co-IP) assays. We further found that SelP interacts with the C-terminus of tubulin by its His-rich domain, as demonstrated by FRET and Isothermal Titration Calorimetry (ITC) assays. The implications of the interaction between SelP and tubulin in the brain and in Alzheimer's disease are discussed.

The synergistic effect of curcumin and mitoquinol mesylate on cognitive impairment and the neuropathology of Alzheimer's disease.

Given the complexity and heterogeneity of Alzheimer's disease (AD) pathology, targeted monotherapy drugs may not be effective. Therefore, synergistic combination therapy of curcumin and Mito Q was proposed and evaluated in a triple-transgenic AD model mice (3 × Tg-AD mice). The cognitive ability was assessed using behavioral tests and typical pathological changes were observed through Western blotting and histological analysis. The results demonstrated a significant enhancement in cognitive ability along with the mitigation of typical AD pathological features such as Aß aggregation, tau phosphorylation, and synaptic damage. Notably, the combination therapy demonstrated superior efficacy over individual drugs alone. These findings provide valuable insights for optimizing the development of AD drugs.

Se-methylselenocysteine ameliorates mitochondrial function by targeting both mitophagy and autophagy in the mouse model of Alzheimer's disease.

Background: Alzheimer's disease (AD) exerts tremendous pressure on families and society due to its unknown etiology and lack of effective treatment options. Our previous study had shown that Se-methylselenocysteine (SMC) improved the cognition and synaptic plasticity of triple-transgenic AD (3 × Tg-AD) mice and alleviated the related pathological indicators. We are dedicated to investigating the therapeutic effects and molecular mechanisms of SMC on mitochondrial function in 3 × Tg-AD mice. Methods: Transmission electron microscopy (TEM), western blotting (WB), mitochondrial membrane potential (ΔΨm), mitochondrial swelling test, and mitochondrial oxygen consumption test were used to evaluate the mitochondrial morphology and function. Mitophagy flux and autophagy flux were assessed with immunofluorescence, TEM and WB. The Morris water maze test was applied to detect the behavioral ability of mice. Results: The destroyed mitochondrial morphology and function were repaired by SMC through ameliorating mitochondrial energy metabolism, mitochondrial biogenesis and mitochondrial fusion/fission balance in 3 × Tg-AD mice. In addition, SMC ameliorated mitochondria by activating mitophagy flux via the BNIP3/NIX pathway and triggering autophagy flux by suppressing the Ras/Raf/MEK/ERK/mTOR pathway. SMC remarkably increased the cognitive ability of AD mice. Conclusions: This research indicated that SMC might exert its therapeutic effect by protecting mitochondria in 3 × Tg-AD mice.

In vivo visualization of enantioselective targeting of amyloid and improvement of cognitive function by clickable chiral metallohelices.

The pathogenesis of Alzheimer's disease (AD) is closely related to several contributing factors, especially amyloid-ß (Aß) aggregation. Bioorthogonal reactions provide a general, facile, and robust route for the localization and derivatization of Aß-targeted agents. Herein, a pair of chiral alkyne-containing metallohelices (ΛA and ΔA) were demonstrated to enantioselectively target and modulate Aß aggregation, which has been monitored in triple-transgenic AD model mice and proved to improve cognitive function. Compared with its enantiomer ΔA, ΛA performed better in blocking Aß fibrillation, relieving Aß-triggered toxicity, and recovering memory deficits in vivo. Moreover, clickable ΛA could act as a functional module for subsequent visualization and versatile modification of amyloid via bioorthogonal reaction. As a proof-of-concept, thioflavin T, tacrine, and magnetic nanoparticles were conjugated with ΛA to realize Aß photo-oxygenation, acetylcholinesterase inhibition, and Aß clearance, respectively. This proof-of-principle work provided new insights into the biolabeling and bioconjugation of multifunctional metallosupramolecules through click reactions for AD therapy.

The protective effects of Esculentoside A through AMPK in the triple transgenic mouse model of Alzheimer's disease.

BACKGROUND: Neurofibrillary tangles comprising hyperphosphorylated tau are vital factors associated with the pathogenesis of Alzheimer's disease (AD). The elimination or reduction of hyperphosphorylated and abnormally aggregated tau is a valuable measure in AD therapy. Esculentoside A (EsA), isolated from Phytolacca esculenta, exhibits pharmacotherapeutic efficacy in mice with amyloid beta-induced AD. However, whether EsA affects tau pathology and its specific mechanism of action in AD mice remains unclear. PURPOSE: To investigate the roles and mechanisms of EsA in cognitive decline and tau pathology in a triple transgenic AD (3 × Tg-AD) mouse model. METHODS: EsA (5 and 10 mg/kg) was administered via intraperitoneal injection to 8-month-old AD mice for eight consecutive weeks. Y-maze and novel object recognition tasks were used to evaluate the cognitive abilities of mice. Potential signaling pathways and targets in EsA-treated AD mice were assessed using quantitative proteomic analysis. The NFT levels and hippocampal synapse numbers were investigated using Gallyas-Braak silver staining and transmission electron microscopy, respectively. Western blotting and immunofluorescence assays were used to measure the expression of tau-associated proteins. RESULTS: EsA administration attenuated memory and recognition deficits and synaptic damage in AD mice. Isobaric tags for relative and absolute quantitation proteomic analysis of the mouse hippocampus revealed that EsA modulated the expression of some critical proteins, including brain-specific angiogenesis inhibitor 3, galectin-1, and Ras-related protein 24, whose biological roles are relevant to synaptic function and autophagy. Further research revealed that EsA upregulated AKT/GSK3ß activity, in turn, inhibited tau hyperphosphorylation and promoted autophagy to clear abnormally phosphorylated tau. In hippocampus-derived primary neurons, inhibiting AMP-activated protein kinase (AMPK) activity through dorsomorphin could eliminate the effect of EsA, as revealed by increased tau hyperphosphorylation, downregulated activity AKT/GSK3ß, and blocked autophagy. CONCLUSIONS: To our knowledge, this study is the first to demonstrate that EsA attenuates cognitive decline by targeting the pathways of both tau hyperphosphorylation and autophagic clearance in an AMPK-dependent manner and it shows a high reference value in AD pharmacotherapy research.

Zinc exacerbates tau-induced Alzheimer-like pathology in C57BL/6J mice.

The pathogenesis of Alzheimer's disease (AD) is highly complex and multifactorial. Compared with Aß, the pathological changes associated with tau are more related to the clinical symptoms and more indicative of the severity of AD. Studies have shown that the direct interaction between tau and Zn2+ plays an important role in tau toxicity, however, the mechanism by which Zn2+ contributes to tau-induced neurotoxicity is not fully understood. Our previous studies have found that Zn2+ bound to the third repeat unit of the microtubule-binding domain of tau (R3) with moderate affinity and induced R3 to form oligomers, thus increased the toxicity of R3 to nerve cells. Here, we demonstrated that Zn2+ binding to R3 (Zn2++R3) significantly reduced cognitive ability and increased blood lipid and glucose levels of C57BL/6J mice. In addition, Zn2++R3, not Zn2+ or R3 alone, markedly enhanced the endogenous Aß and tau pathology and damaged the neurons of C57BL/6J mice. The study suggests that the main reason for the toxicity of Zn2+ may be the formation of Zn2+ and tau complex. Thus, preventing the combination of Zn2+ and tau may be a potential strategy for AD treatment. Furthermore, as the C57BL/6J mice injected with Zn2++R3 complex showed behavioral deficits, deposition of Aß plaques and tau tangles, and the death of neurons within 45 days. Thus, they can be considered as a fast sporadic AD or other tauopathies mouse model.

The pharmacology and therapeutic role of cannabidiol in diabetes.

In recent years, cannabidiol (CBD), a non-psychotropic cannabinoid, has garnered substantial interest in drug development due to its broad pharmacological activity and multi-target effects. Diabetes is a chronic metabolic disease that can damage multiple organs in the body, leading to the development of complications such as abnormal kidney function, vision loss, neuropathy, and cardiovascular disease. CBD has demonstrated significant therapeutic potential in treating diabetes mellitus and its complications owing to its various pharmacological effects. This work summarizes the role of CBD in diabetes and its impact on complications such as cardiovascular dysfunction, nephropathy, retinopathy, and neuropathy. Strategies for discovering molecular targets for CBD in the treatment of diabetes and its complications are also proposed. Moreover, ways to optimize the structure of CBD based on known targets to generate new CBD analogues are explored.

DHA Ameliorates Cognitive Ability, Reduces Amyloid Deposition, and Nerve Fiber Production in Alzheimer's Disease.

Background: The etiology of Alzheimer's disease (AD) is very complex. Docosahexaenoic acid (DHA) is important in cognitive ability and nervous system development. A limited number of studies have evaluated the efficacy of DHA in the treatment of AD. Introduction: We detected neurofibrillary tangles (NFT) in the hippocampus and cortex of transgenic mice brain through silver glycine staining. We determined the activity of neurons by staining Nissl bodies, used liquid NMR to detect metabolites in the brain, and functional magnetic resonance imaging results to observe the connection signal value between brain regions. Materials and Methods: We fed 3-month-old APP/PS1 double transgenic mice with DHA mixed feeds for 4 months to assess the effects of DHA on cognitive ability in AD mice through the Morris water maze and open field tests. To evaluate its effects with AD pathology, continuous feeding was done until the mice reached 9 months of age. Results: Compared to AD mice, escape latency significantly decreased on the fifth day while swimming speed, target quadrant stay time, and the crossing number of platforms increased by varying degrees after DHA treatment. Brain tissue section staining revealed that DHA significantly reduced Aß and nerve fibers in the brain of AD mice. Conclusion: DHA significantly reduced the deposition of Aß in the brain and inhibited the production of nerve fibers, thereby increasing cognitive abilities in AD mice. In addition, DHA suppressed blood lipid levels, and restored uric acid and urea levels, implying that DHA is a potential therapeutic option for early AD.