Study of multifunctional anti-AD ligands: design, synthesis, X-ray crystal structure and biological evaluation of diosmetin derivatives.

The development of anti-AD drugs has attracted much attention as the number of AD patients is increasing year by year. Five diosmetin derivatives (1-5) were designed and synthesized by introducing carbamate groups. The crystal structure of 1 was analyzed by X-ray diffraction, which showed a large conjugated coplanar structure and might be favorable for the insertion into the Aß folding. Meanwhile, in vitro experiments were carried out to investigate the anticholinesterase activity, metal chelating property, antioxidant activity, and anti-Aß aggregation ability of 1-5. The results showed that 1-5 had good cholinesterase inhibitory activities. Compound 4 showed the highest inhibitory activities against butyrylcholinesterase (IC50 = 0.0760 µM). Further kinetic experiments and molecular docking studies showed that 4 could bind well to butyrylcholinesterase. The molecular dynamics simulations also signified that compared with diosmetin, 4 could reduce the flexibility of the butyrylcholinesterase protein skeleton to a greater extent, and thus had a better inhibitory effect. In addition, 1-5 could selectively chelate copper ions and all of them had good antioxidant activity as well as anti-Aß aggregation ability. Among them, 4 had the strongest activity to inhibit Cu2+-induced Aß aggregation (51.09%) and had low cytotoxicity. In addition, in vivo ROS activity assay (Caenorhabditis elegans) showed that 4 had the ability to scavenge ROS. Besides, the in vivo Aß aggregation assay showed that 4 could reduce Aß aggregation. In conclusion, 4 has the potential to be developed into a multifunctional anti-AD drug.

miRNA-137-5p improves spatial memory and cognition in Alzheimer's mice by targeting ubiquitin-specific peptidase 30.

BACKGROUND: Alzheimer's disease (AD) is a prevalent neurodegenerative disorder causing progressive dementia. Research suggests that microRNAs (miRNAs) could serve as biomarkers and therapeutic targets for AD. Reduced levels of miR-137 have been observed in the brains of AD patients, but its specific role and downstream mechanisms remain unclear. This study sought to examine the therapeutic potential of miR-137-5p agomir in alleviating cognitive dysfunction induced in AD models and explore its potential mechanisms. METHODS: This study utilized bioinformatic analysis and a dual-luciferase reporter assay to investigate the relationship between miR-137-5p and ubiquitin-specific peptidase 30 (USP30). In vitro experiments were conducted using SH-SY5Y cells to assess the impact of miR-137-5p on Aß1-42 neurotoxicity. In vivo experiments on AD mice evaluated the effects of miR-137-5p on cognition, Aß1-42 deposition, Tau hyperphosphorylation, and neuronal apoptosis, as well as its influence on USP30 levels. RESULTS: It was discovered that miR-137-5p mimics efficiently counteract Aß1-42 neurotoxicity in SH-SY5Y cells, a protective effect that is negated by USP30 overexpression. In vivo experiments demonstrated that miR-137-5p enhances the cognition and mobility of AD mice, significantly reducing Aß1-42 deposition, Tau hyperphosphorylation, and neuronal apoptosis within the hippocampus and cortex regions. Mechanistically, miR-137-5p significantly suppresses USP30 levels in mice, though USP30 overexpression partially buffers against miR-137-5p-induced AD symptom improvement. CONCLUSION: Our study proposes that miR-137-5p, by instigating the downregulation of USP30, has the potential to act as a novel and promising therapeutic target for AD.

Betula pendula Leaf Extract Targets the Interplay between Brain Oxidative Stress, Inflammation, and NFkB Pathways in Amyloid Aß1-42-Treated Rats.

Alzheimer's disease (AD) is known as the primary and most common cause of dementia in the middle-aged and elderly population worldwide. Chemical analyses of B. pendula leaf extract (BPE), performed using spectrophotometric and chromatographic methods (LC/MS), revealed high amounts of polyphenol carboxylic acids (gallic, chlorogenic, caffeic, trans-p-coumaric, ferulic, and salicylic acids), as well as flavonoids (apigenin, luteolin, luteolin-7-O-glucoside, naringenin, hyperoside, quercetin, and quercitrin). Four groups of Wistar rats were used in this experiment (n = 7/group): control (untreated), Aß1-42 (2 µg/rat intracerebroventricular (i.c.v.), Aß1-42 + BPE (200 mg/Kg b.w.), and DMSO (10 µL/rat). On the first day, one dose of Aß1-42 was intracerebroventricularly administered to animals in groups 2 and 3. Subsequently, BPE was orally administered for the next 15 days to group 3. On the 16th day, behavioral tests were performed. Biomarkers of brain oxidative stress Malondialdehyde (MDA), (Peroxidase (PRx), Catalase (CAT), and Superoxid dismutase (SOD) and inflammation (cytokines: tumor necrosis factor -α (TNF-α), Interleukin 1ß (IL-1ß), and cyclooxygenase-2 (COX 2)) in plasma and hippocampus homogenates were assessed. Various protein expressions (Phospho-Tau (Ser404) (pTau Ser 404), Phospho-Tau (Ser396) (pTau Ser 396), synaptophysin, and the Nuclear factor kappa B (NFkB) signaling pathway) were analyzed using Western blot and immunohistochemistry in the hippocampus. The results show that BPE diminished lipid peroxidation and neuroinflammation, modulated specific protein expression, enhanced the antioxidant capacity, and improved spontaneous alternation behavior, suggesting that it has beneficial effects in AD.

[Lead exposure aggravates Aß1-42-induced microglial activation and copper ion accumulation in microglial cells].

OBJECTIVE: To investigate the effect of lead (Pb) exposure on Aß1-42-induced microglial activation and copper ion accumulation in microglial cells and explore the regulatory mechanism of Pb-induced aggravation of Alzheimer's disease (AD)-like pathology. METHODS: Cultured microglial BV2 cells were treated with different concentrations of Aß1-42, lead acetate or their combination for 12 h, and the changes in cell viability and morphology were evaluated. Immunofluorescence assay was performed to detect iNOS and oxidative stress level in the treated cells, and the release of inflammatory factors was detected using ELISA. Western blotting and inductively coupled plasma-mass spectrometry (ICP-MS) were used to detect the expressions of CTR1 and ATP7A proteins and copper content in the cells. RESULTS: Treatment with 15 and 20 µmol/L Aß1-42 for 12 h significantly lowered the viability of BV2 cells. Treatment with Aß1-42 at 10 µmol/L for 12 h obviously increased the release of iNOS, TNF-α and IL-6 in the cells (P<0.05), and its combination with 15 or 20 µmol/L lead acetate more strongly lowered BV2 cell viability (P<0.05). Compared with 10 µmol/L Aß1-42 treatment alone, 10 µmol/L Aß1-42 combined with 10 µmol/L lead acetate for 12 h caused more obvious microglial activation, as manifested by enlarged cell bodies, increased cell protrusions and elongation, enhanced release of iNOS, TNF-α, IL-6, IL-1ß and ROS, and increased intracellular copper ion accumulation and expression of copper transporter CTR1 (P<0.05). Compared with the conditioned medium from activated BV2 cells, which caused obvious injuries in hippocampal neuron HT22 cells (P<0.001), the medium from BV2 cells treated with NAC and the copper ion chelating agent TM caused milder injuries in HT22 cells (P<0.05). CONCLUSION: Lead exposure aggravates neuronal damage caused by Aß1-42-treated microglial cells by increasing copper ion accumulation, oxidative stress, and inflammatory factor release to trigger microglial activation.

miR-6076 targets BCL6 in SH-SY5Y cells to regulate amyloid-ß-induced neuronal damage.

Amyloid-ß1-42 (Aß1-42 ) is strongly associated with Alzheimer's disease (AD). The aim of this study is to elucidate whether and how miR-6076 participates in the modulation of amyloid-ß (Aß)-induced neuronal damage. To construct the neuronal damage model, SH-SY5Y cells were treated with Aß1-42 . By qRT-PCR, we found that miR-6076 is significantly upregulated in Aß1-42 -treated SH-SY5Y cells. After miR-6076 inhibition, p-Tau and apoptosis levels were downregulated, and cell viability was increased. Through online bioinformatics analysis, we found that B-cell lymphoma 6 (BCL6) was a directly target of miR-6076 via dual-luciferase reporter assay. BCL6 overexpression mediated the decrease in elevated p-Tau levels and increased viability in SH-SY5Y cells following Aß1-42 treatment. Our results suggest that down-regulation of miR-6076 could attenuate Aß1-42 -induced neuronal damage by targeting BCL6, which provided a possible target to pursue for prevention and treatment of Aß-induced neuronal damage in AD.

Emodin derivatives as promising multi-aspect intervention agents for amyloid aggregation: molecular docking/dynamics simulation, bioactivities evaluation, and cytoprotection.

Alzheimer's disease (AD) is a progressive neurodegenerative disease with complex pathogenesis. Despite the pathogenesis is unknown, the misfolding and accumulation of ß-amyloid (Aß) peptide play the important role in the occurrence and development of AD. Hence, multi-aspect intervention of the misfolded Aß peptides aggregation is a promising therapy for AD. In previous work, we obtained the emodin derivatives (a-d) with multifunctional anti-AD activities, including metal ions chelation, cholinesterase inhibition, and hydroxyl/superoxide anion radical elimination. In this work, we predicted the interaction of emodin derivatives (a-d) with Aß by combining molecular docking simulation and molecular dynamics simulation, and evaluated the ability to intervene with the self-, Cu2+- and AChE-induced Aß aggregation via in vitro methods. The results indicated that a-d could act as the potent multi-aspect intervention agents for Aß aggregation. In addition, a-d could effectively eliminate peroxyl radical, had virtually no neurotoxicity, and protect cells from oxidative and Aß-induced damage. The prediction results of ADMET properties showed that a-d had suitable pharmacokinetic characteristics. It suggested that a-d could act as the promising multi-targeted directed ligands (MTDLs) for AD. These results may provide meaningful information for the development of the potential MTDLs for AD which are modified from natural-origin scaffolds.

Neuroprotective Iridoids and Lignans from Valeriana amurensis.

Valeriana amurensis (V. amurensis) is widely distributed in Northeast China. In addition to medicines, it has also been used to prepare food, wine, tobacco, cosmetics, perfume, and functional foods. Other studies have investigated the neuroprotective effects of V. amurensis extract. As the therapeutic basis, the active constituents should be further evaluated. In this paper, six new compounds (1-6) were isolated, including five iridoids (Xiecaoiridoidside A-E) and one bisepoxylignan (Xiecaolignanside A), as well as six known compounds (7-12). The neuroprotective effects of 1-12 were also investigated with amyloid ß protein 1-42 (Aß1-42)-induced injury to rat pheochromocytoma (PC12) cells. As a result, iridoids 1 and 2 and lignans 6, 8, and 9 could markedly maintain the cells' viability by 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide (MTT) and lactate dehydrogenase (LDH) release assay.

The effects of high plasma levels of Aß1-42 on mononuclear macrophage in mouse models of Alzheimer's disease.

More and more evidences are proving that microglia play a crucial role in the pathogenesis of Alzheimer's disease (AD) and the plasma Aß1-42 levels significantly increased 15 years before the onset of dominantly inherited AD. However, the effects of high plasma levels of Aß1-42 on mononuclear macrophage, the peripheral counterparts of microglia, remain unclear. In the present study, we used APP/PS1 transgenic (Tg) mice and a parabiotic model of wild type (Wt) mice and Tg mice (Parabiotic Wt-Tg, Pa (Wt-Tg)) to investigate the effects of high plasma levels of Aß1-42 on peripheral mononuclear macrophage. Our results showed that in the early stage of Tg mice (7 months) and Pa (Wt-Tg) mice (4 months), the proportions of pro-inflammatory macrophages in peritoneal cavity, myeloid derived suppressor cells (MDSCs) in spleen, granulocyte-monocyte progenitors (GMPs) in bone marrow, and the plasma levels of interleukin-6 (IL-6) were significantly decreased. While the proportions of pro-inflammatory macrophages, MDSCs, GMPs, and the plasma levels of IL-6 and tumor necrosis factor (TNF)-α, as well as the numbers of bone marrow-derived macrophages (BMDMs) in mice brain were increased in the late stage of Tg mice (11 months) and Pa (Wt-Tg) mice (8 months). In addition, the proportions of monocytes in spleen and the proliferation of bone marrow cells (BMCs) were enhanced consistently, and the phagocytic function of macrophages kept stably after high plasma levels of Aß1-42 sustaining stimulation. These results demonstrated that high plasma levels of Aß1-42 play a biphasic regulating role at different stages of the disease, namely inhibiting effects on peripheral pro-inflammatory macrophages in the early stage of AD model, while promoting effects in the late stage of AD model. The mechanism behind this may be associated with their effects on MDSCs in spleen and myeloid progenitor cells in bone marrow. Therefore, intervening the effects of plasma Aß1-42 on pro-inflammatory macrophages might offer a new therapeutic approach to AD.

Aß1-42-containing platelet-derived extracellular vesicle is associated with cognitive decline in Parkinson's disease.

Background: Cortical amyloid deposition is a common observation in Parkinson's disease dementia (PDD) patients. Aß1-42 is linked to a more rapid progression of dementia. Platelets, which degranulate upon activation, are a primary source of Aß. It has been repeatedly reported that peripheral extracellular vesicles (EVs) can partially reach the central nervous system. Thus, we speculate that activated platelet-derived Aß1-42-containing EVs (PEV-Aß1-42) play a crucial role in the cognitive decline of PD patients. Methods: The study included 189 participants: 66 with non-dementia PD, 73 with PDD, and 50 healthy controls. All participants underwent blood collection and clinical assessments. Twenty PD patients underwent re-examination and repeated blood collection 14 months later. A nano-scale flow cytometry assay was used to detect PEVs and PEV-Aß1-42 using fluorescence-labeled CD62P and Aß1-42 antibodies. Results: Parkinson's disease dementia patients had higher PEV-Aß1-42 concentrations than healthy controls (p = 0.028). The ratio of PEV-Aß1-42 to PEV was significantly higher in PDD patients compared to those in non-dementia PD and healthy controls (p PD-ND < 0.001, p HC = 0.041). The PEV-Aß1-42/PEV ratio appears to influence the odds of developing dementia (OR = 1.76, p < 0.001). The change in the PEV-Aß1-42/PEV ratio was also correlated with cognitive decline over 14 months (r = -0.447, p < 0.05). Conclusion: The plasma PEV-Aß1-42/PEV ratio may serve as a diagnostic and prognostic biomarker for PDD patients.

Magnoflorine improves cognitive deficits and pathology of Alzheimer's disease via inhibiting of JNK signaling pathway.

BACKGROUND: Cognitive deficit is the main clinical feature of Alzheimer's disease (AD), and the massive death of neuronal cells is the leading cause of cognitive deficits. So, there is an urgent clinical need to discover effective drugs to protect brain neurons from damage in order to treat AD. Naturally-derived compounds have always been an important source of new drug discovery because of their diverse pharmacological activities, reliable efficacy and low toxicity. Magnoflorine is a quaternary aporphine alkaloid, which naturally exist in some commonly used herbal medicines, and has good anti-inflammatory and antioxidant effects. However, magnoflorine has not been reported in AD. HYPOTHESIS/PURPOSE: To investigate the therapeutic effect and mechanism of magnoflorine on AD. METHODS: Neuronal damage was detected by flow cytometry, immunofluorescence and western blotting. Oxidative stress was measured by detection of SOD and MDA, as well as JC-1 and reactive oxygen species (ROS) staining. The APP/PS1 mice were given drugs by intraperitoneal injection (I.P.) every day for one month, and then the new object recognition and Morris water maze were used to detect the cognitive ability of the mice. RESULTS: We demonstrated that magnoflorine reduced Aß-induced PC12 cell apoptosis and intracellular ROS generation. Further studies found that magnoflorine significantly improved cognitive deficits and AD-type pathology. Most interestingly, the efficacy of magnoflorine was better than that of the clinical control drug donepezil. Mechanistically, based on RNA-sequencing analysis, we found that magnoflorine significantly inhibited phosphorylated c-Jun N-terminal kinase (JNK) in AD models. This result was further validated using a JNK inhibitor. CONCLUSION: Our results indicate that magnoflorine improves cognitive deficits and pathology of AD through inhibiting of JNK signaling pathway. Thus, magnoflorine may be a potential therapeutic candidate for AD.

Luteolin and Exercise Combination Therapy Ameliorates Amyloid-ß1-42 Oligomers-Induced Cognitive Impairment in AD Mice by Mediating Neuroinflammation and Autophagy.

BACKGROUND: Alzheimer's disease (AD) disturbs many patients and family. However, little progress has been made in finding effective treatments. Given AD is a multifactorial disease, luteolin and exercise combination therapy may be more effective than monotherapy. OBJECTIVE: To explore the therapeutic effect and underlying mechanisms of luteolin and exercise combination therapy in AD treatment. METHODS: This study utilized a validated mouse model of AD by bilateral injection of amyloid-ß (Aß)1-42 oligomers into the CA1 region of the hippocampus. By combining with animal behavioral test, thioflavin T detection, immunofluorescence and western blot test, the cognitive-enhancing effects of luteolin and exercise combination therapy and the underlying mechanisms were investigated. RESULTS: Luteolin (100 mg/kg/d) combined with exercise could significantly improve the performance of AD model mice in novel object recognition test, and the improvement was greater than that of monotherapy. Further experiments showed that luteolin and exercise alone or in combination could reverse the increase of Aß content, the activation of astrocytes and microglia, and the decrease of the level of autophagy in hippocampus and cortex in AD model induced by Aß1-42 oligomers. While the combination therapy involved more intact hippocampal and cortical areas, with greater degree of changes. CONCLUSION: Luteolin and exercise combination therapy prevented Aß1-42 oligomers-induced cognitive impairment, possibly by decreasing neuroinflammation and enhancing autophagy. The luteolin and exercise combination therapy may be a useful therapeutic option for preventing and/or delaying the progression of memory dysfunction of AD.

Effects of diverse Types of Toxoplasma gondii on the outcome of Alzheimer's disease in the rat model.

Toxoplasma gondii has lifelong persistence in the brain and its cysts can affect gene expression and change diverse biological functions of neurons. Many studies indicated T. gondii infection as a risk factor for the development of behavioral changes and neurodegenerative diseases such as Alzheimer's disease (AD), although the etiopathogenetic link between them has not been exactly elucidated. The current study aimed to examine the effects of chronic toxoplasmosis infection with Types I, II, and III strains (RH, PRU, and VEG) alone and in combination on cognitive impairments and neuronal death in the Aß1-42-induced rat model of Alzheimer's disease. In the chronic toxoplasmosis phase, Alzheimer's induction was conducted by injecting Aß1-42 oligomers into the rat brain hippocampus. Behavioral tests were conducted 10 days after the AD induction. Real-time PCR was performed to evaluate T. gondii parasite burden by amplification of the B1 gene. Cytokines IL-1ß, TNF-α, and IL-10 were assayed in brain tissue supernatant using ELISA. Also, histopathological examinations were conducted to calculate inflammatory changes and neuronal death in the brain. Our findings showed that chronic toxoplasmosis infection with PRU reduces cognitive disorders, while the RH strain of T. gondii plays a destructive role and aggravates cognitive impairments in AD. Also, infection with a combination of PRU and VEG strains significantly improved spatial learning and memory impairments in Alzheimer's rat model. Histopathological findings also confirmed the results of behavioral tests, so that in AßPRU and AßPRU + VEG groups, neuronal death and infiltration of inflammatory cells were negligible and significantly less than in Alzheimer's and AßRH groups. Our findings indicate that chronic toxoplasmosis infection with PRU strain alone, also in combination with VEG strain can significantly improve cognitive disorders in AD rats, while RH strain plays a destructive role in AD pathogenesis.

The Real-Time Validation of the Effectiveness of Third-Generation Hyperbranched Poly(ɛ-lysine) Dendrons-Modified KLVFF Sequences to Bind Amyloid-ß1-42 Peptides Using an Optical Waveguide Light-Mode Spectroscopy System.

The aggregation of cytotoxic amyloid peptides (Aß1-42) is widely recognised as the cause of brain tissue degeneration in Alzheimer's disease (AD). Indeed, evidence indicates that the deposition of cytotoxic Aß1-42 plaques formed through the gradual aggregation of Aß1-42 monomers into fibrils determines the onset of AD. Thus, distinct Aß1-42 inhibitors have been developed, and only recently, the use of short linear peptides has shown promising results by either preventing or reversing the process of Aß1-42 aggregation. Among them, the KLVFF peptide sequence, which interacts with the hydrophobic region of Aß16-20, has received widespread attention due to its ability to inhibit fibril formation of full-length Aß1-42. In this study, hyperbranched poly-L-lysine dendrons presenting sixteen KLVFF at their uppermost molecular branches were designed with the aim of providing the KLVFF sequence with a molecular scaffold able to increase its stability and of improving Aß1-42 fibril formation inhibitory effect. These high-purity branched KLVFF were used to functionalise the surface of the metal oxide chip of the optical waveguide lightmode spectroscopy sensor showing the more specific, accurate and rapid measurement of Aß1-42 than that detected by linear KLVFF peptides.

Calcium inhibits penetration of Alzheimer's Aß1 -42 monomers into the membrane.

Calcium ion regulation plays a crucial role in maintaining neuronal functions such as neurotransmitter release and synaptic plasticity. Copper (Cu2+ ) coordination to amyloid-ß (Aß) has accelerated Aß1-42 aggregation that can trigger calcium dysregulation by enhancing the influx of calcium ions by extensive perturbing integrity of the membranes. Aß1-42 aggregation, calcium dysregulation, and membrane damage are Alzheimer disease (AD) implications. To gain a detail of calcium ions' role in the full-length Aß1-42 and Aß1-42 -Cu2+ monomers contact, the cellular membrane before their aggregation to elucidate the neurotoxicity mechanism, we carried out 2.5 µs extensive molecular dynamics simulation (MD) to rigorous explorations of the intriguing feature of the Aß1-42 and Aß1-42 -Cu2+ interaction with the dimyristoylphosphatidylcholine (DMPC) bilayer in the presence of calcium ions. The outcome of the results compared to the same simulations without calcium ions. We surprisingly noted robust binding energies between the Aß1-42 and membrane observed in simulations containing without calcium ions and is two and a half fold lesser in the simulation with calcium ions. Therefore, in the case of the absence of calcium ions, N-terminal residues of Aß1-42 deeply penetrate from the surface to the center of the bilayer; in contrast to calcium ions presence, the N- and C-terminal residues are involved only in surface contacts through binding phosphate moieties. On the other hand, Aß1-42 -Cu2+ actively participated in surface bilayer contacts in the absence of calcium ions. These contacts are prevented by forming a calcium bridge between Aß1-42 -Cu2+ and the DMPC bilayer in the case of calcium ions presence. In a nutshell, Calcium ions do not allow Aß1-42 penetration into the membranes nor contact of Aß1-42 -Cu2+ with the membranes. These pieces of information imply that the calcium ions mediate the membrane perturbation via the monomer interactions but do not damage the membrane; they agree with the western blot experimental results of a higher concentration of calcium ions inhibit the membrane pore formation by Aß peptides.

Inhibition of Alzheimer's Aß1-42 Fibrillogenesis and Removal of Copper Ions by Polypeptides Modified Gold Nanoparticles.

Aggregation and fibrillation of ß-amyloid peptides (Aß) as well as accumulation of toxic metal ions have been believed to be the central events to cause Alzheimer's disease (AD). Thus, an attractive therapeutic tactic for AD is to design and synthesize inhibitors and metal chelators to prevent Aß aggregation and chelate toxic metal ions. In this study, the polypeptide functionalized gold nanoparticles (PFGNP) were obtained by modifying polypeptides Cys-Gly-Gly-Gly-Leu-Pro-Phe-Phe-Asp (CGGGLPFFD) and Cys-Gly-Gly-Gly-Gly-Gly-His (CGGGGGH) onto gold nanoparticles through gold-sulfur bond. The inhibitory properties of PFGNP toward Aß1-42 fibril formation was assessed by thioflavin T (ThT) fluorescence method and corroborated by atomic force microscopy analysis. The ability of PFGNP to complex copper ions was studied by electrochemical method. The experimental results reveal that PFGNP can effectively chelate copper ions and significantly inhibit the fibrillation of Aß1-42 . Moreover, PFGNP exhibits significantly protective effect on Aß-induced cytotoxicity toward human neuroblastoma SH-SY5Y cells.

Identification of Leukocyte Surface P2X7 as a Biomarker Associated with Alzheimer's Disease.

Alzheimer's disease (AD) has shown altered immune responses in the periphery. We studied P2X7 (a proinflammatory receptor and a scavenger receptor) and two integrins, CD11b and CD11c, on the surface of circulating leukocytes and analysed their associations with Aß-PET, brain atrophy, neuropsychological assessments, and cerebrospinal fluid (CSF) biomarkers. Total 287 age-matched, sex-balanced participants were recruited in a discovery cohort and two validation cohorts through the AIBL study and studied using tri-colour flow cytometry. Our results demonstrated reduced expressions of P2X7, CD11b, and CD11c on leukocytes, particularly monocytes, in Aß +ve cases compared with Aß -ve controls. P2X7 and integrin downregulation was observed at pre-clinical stage of AD and stayed low throughout disease course. We further constructed a polygenic risk score (PRS) model based on 12 P2RX7 risk alleles to assess the genetic impact on P2X7 function in AIBL and ADNI cohorts. No significant association was identified between the P2RX7 gene and AD, indicating that P2X7 downregulation in AD is likely caused by environmental changes rather than genetic factors. In conclusion, the downregulation of P2X7 and integrins at pre-clinical stage of AD indicates altered pro-inflammatory responses, phagocytic functions, and migrating capabilities of circulating monocytes in early AD pathogenesis. Our study not only improves our understanding of peripheral immune involvement in early stage of AD but also provides more insights into novel biomarker development, diagnosis, and prognosis of AD.

[Electroacupuncture improves learning-memory ability by down-regulating expression of hippocampal Aß1-42 and Tau and NF-κB proteins in diabetic rats with cognitive impairment].

OBJECTIVE: To observe the effect of electroacupuncture(EA) on the expression of nuclear transcription factors κB (NF-κB) and Tau protein and content of amyloid (Aß) in diabetic rats with cognitive impairment, so as to explore its mechanism underlying improvement of learning-memory ability. METHODS: Male SD rats were randomly divided into normal control (n=9), model (n=9) and EA (n=9) groups. The diabetic mellitus model was established by feeding the rats with high fat and high sugar for 1 month and intraperitoneal injection of STZ (25 mg·kg-1·d-1) for 2 days. EA was applied to "Zusanli"(ST36) and "Neiting"(ST44) for 20 min, alternatively on both side every day, and "Yishu"(EX-B3) was stimulated by twirling the acupuncture needle with uniform reinforcing-reducing method for 1 min, followed by retaining it for 20 min. The treatment was conducted 6 times a week for 4 weeks. The learning-memory ability was evaluated by using Morris water maze swimming test. The blood glucose level was randomly detected by using a glucometer, the content of Aß1-42 in the hippocampal tissue was detected by ELISA, and the relative expression levels of hippocampal Tau and NF-κB p65 proteins and mRNAs were determined by Western blot and fluorescence quantitative real-time PCR, separately. RESULTS: After modeling, the blood glucose, escape latency, Aß1-42 content and the expression levels of Tau and NF-κB p65 proteins and mRNAs in the model group were significantly increased (P<0.01, P<0.05) in comparison with the normal control group. Following EA intervention, the modeling induced increase of blood glucose, escape latency, Aß1-42 content and the expression levels of Tau and NF-κB p65 proteins and mRNAs were reversed (P<0.05, P<0.01). CONCLUSION: EA can improve the learning-memory ability in rats with diabetic cognitive impairment, which may be related to its function in down-regulating the levels of hippocampal Aß1-42, Tau and NF-κB proteins.

Cannabidiol Enhances Microglial Beta-Amyloid Peptide Phagocytosis and Clearance via Vanilloid Family Type 2 Channel Activation.

Alzheimer's disease (AD) is associated with the accumulation and aggregation of amyloid in the brain. The cation channel TRPV2 may mediate the pathological changes in mild cognitive impairment. A high-affinity agonist of TRPV2 named cannabidiol is one of the candidate drugs for AD. However, the molecular mechanism of cannabidiol via TRPV2 in AD remains unknown. The present study investigated whether cannabidiol enhances the phagocytosis and clearance of microglial Aß via the TRPV2 channel. We used a human dataset, mouse primary neuron and microglia cultures, and AD model mice to evaluate TRPV2 expression and the ability of microglial amyloid-ß phagocytosis in vivo and in vitro. The results revealed that TRPV2 expression was reduced in the cortex and hippocampus of AD model mice and AD patients. Cannabidiol enhanced microglial amyloid-ß phagocytosis through TRPV2 activation, which increased the mRNA expression of the phagocytosis-related receptors, but knockdown of TRPV2 or Trem2 rescued the expression. TRPV2-mediated effects were also dependent on PDK1/Akt signaling, a pathway in which autophagy was indispensable. Furthermore, cannabidiol treatment successfully attenuated neuroinflammation while simultaneously improving mitochondrial function and ATP production via TRPV2 activation. Therefore, TRPV2 is proposed as a potential therapeutic target in AD, while CBD is a promising drug candidate for AD.

Microemulsion Delivery System Improves Cellular Uptake of Genipin and Its Protective Effect against Aß1-42-Induced PC12 Cell Cytotoxicity.

Genipin has attracted much attention for its hepatoprotective, anti-inflammatory, and neuroprotection activities. However, poor water solubility and active chemical properties limit its application in food and pharmaceutical industries. This article aimed to develop a lipid-based microemulsion delivery system to improve the stability and bioavailability of genipin. The excipients for a genipin microemulsion (GME) preparation were screened and a pseudo-ternary phase diagram was established. The droplet size (DS), zeta potential (ZP), polydispersity index (PDI), physical and simulated gastrointestinal digestion stability, and in vitro drug release properties were characterized. Finally, the effect of the microemulsion on its cellular uptake by Caco-2 cells and the protective effect on PC12 cells were investigated. The prepared GME had a transparent appearance with a DS of 16.17 ± 0.27 nm, ZP of -8.11 ± 0.77 mV, and PDI of 0.183 ± 0.013. It exhibited good temperature, pH, ionic strength, and simulated gastrointestinal digestion stability. The in vitro release and cellular uptake data showed that the GME had a lower release rate and better bioavailability compared with that of free genipin. Interestingly, the GME showed a significantly better protective effect against amyloid-ß (Aß1-42)-induced PC12 cell cytotoxicity than that of the unencapsulated genipin. These findings suggest that the lipid-based microemulsion delivery system could serve as a promising approach to improve the application of genipin.

CircAXL Knockdown Alleviates Aß1-42-Induced Neurotoxicity in Alzheimer's Disease via Repressing PDE4A by Releasing miR-1306-5p.

The development of Alzheimer's disease (AD) is implicated with the dysregulation of numerous circular RNAs (circRNAs). However, the function of several circRNAs remains unclear. The aim of this study was to investigate the role of circular AXL receptor tyrosine kinase (circAXL) in AD. Cell models of AD were constructed by treating SK-N-SH cells with amyloid-ß (Aß1-42). The expression of circAXL, miR-1306-5p and phosphodiesterase 4A (PDE4A) mRNA was detected by quantitative real-time PCR (qPCR). Cell viability was checked by CCK-8 assay. The production of inflammatory factors was monitored by ELISA. Cell apoptosis was checked by flow cytometry assay. Oxidative stress was assessed by ROS level, MDA level and SOD activity using commercial kits. Endoplasmic reticulum (ER) stress was assessed by ER-related protein markers using western blotting. The relationship between miR-1306-5p and circAXL or PDE4A was validated by RIP assay and dual-luciferase reporter assay. Serum exosomes were isolated by centrifugation to assess the diagnostic value of exosomal circAXL, miR-1306-5p and PDE4A. CircAXL was overexpressed in Aß1-42-treated SK-N-SH cells. CircAXL knockdown alleviated Aß1-42-induced cell cytotoxicity, cell apoptosis, inflammation, oxidative stress and endoplasmic reticulum (ER) stress in SK-N-SH cells. MiR-1306-5p was screened as a target of circAXL, and miR-1306-5p inhibition abolished the effects of circAXL knockdown. MiR-1306-5p inhibited the expression of PDE4A, and circAXL regulated PDE4A expression by targeting miR-1306-5p. MiR-1306-5p restoration also alleviated Aß1-42-induced cell injuries, while PDE4A reintroduction abolished the effects of miR-1306-5p restoration. Exosomal circAXL and exosomal miR-1306-5p had diagnostic values for AD. CircAXL knockdown alleviates Aß1-42-induced neurotoxicity in AD pathology via repressing PDE4A by releasing miR-1306-5p.