Discrepancy of synaptic and microtubular protein phosphorylation in the hippocampus of APP/PS1 and MAPT×P301S transgenic mice at the early stage of Alzheimer's disease.

Alzheimer's disease (AD) is the most common neurodegenerative disorder, and is caused by multiple pathological factors, such as the overproduction of ß-amyloid (Aß) and the hyperphosphorylation of tau. However, there is limited knowledge of the mechanisms underlying AD pathogenesis and no effective biomarker for the early diagnosis of this disorder. Thus in this study, a quantitative phosphoproteomics analysis was performed to evaluate global protein phosphorylation in the hippocampus of Aß overexpressing APP/PS1 transgenic mice and tau overexpressing MAPT×P301S transgenic mice, two in vivo AD model systems. These animals, up to ten weeks old, do not exhibit cognitive dysfunctions and are widely used to simulate early-stage AD patients. The number of differentially phosphorylated proteins (DPPs) was greater for APP/PS1 transgenic mice than for MAPT×P301S transgenic mice. The function of the DPPs in APP/PS1 transgenic mice was mainly related to synapses, while the function of the DPPs in MAPT×P301S transgenic mice was mainly related to microtubules. In addition, an AD core network was established including seven phosphoproteins differentially expressed in both animal models, and the function of this core network was related to synapses and oxidative stress. The results of this study suggest that Aß and tau induce different protein phosphorylation profiles in the early stage of AD, leading to the dysfunctions in synapses and microtubule, respectively. And the detection of same DPPs in these animal models might be used for early AD diagnosis.

Hydrophilic, dual amino acid-functionalized zinc sulfide quantum dot for specific identification of N-glycopeptides from biological samples.

RATIONALE: Glycosylation of proteins is one of the most significant and complex post-translational modifications, and N-glycosylation plays a crucial role in life activities. Mass spectrometry (MS) has been a powerful technique in the analysis of protein glycosylation. However, the direct detection of glycoproteins in biological samples based on MS still suffers from huge challenges. Therefore, enrichment and purification of samples before MS analysis is an essential prerequisite. METHODS: Hydrophilic interaction liquid chromatography (HILIC) has significantly developed for selective enrichment of glycopeptides due to its simple operation process and unbiased enrichment. Herein, hydrophilic, dual amino acid-functionalized zinc sulfide quantum dots (ZnS QDs) were prepared to enrich glycopeptides using an easy procedure. The enriched glycopeptides were detected using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). RESULTS: The obtained material exhibited high selectivity (1:2000), low detection limit (0.1 fmol/µl), good repeatability (10 times), and excellent recovery (89.8%) in glycopeptide enrichment. In the actual application in biological samples, 71 N-glycopeptides and 161 N-glycopeptides were detected from human saliva and serum, respectively. CONCLUSIONS: ZnS-Au-GC was successfully prepared using an easy method. The results showed that the obtained material exhibited excellent performance in glycopeptide enrichment. Furthermore, it had showed great potential for glycopeptide enrichment in complex biological samples.

A stepwise-targeting strategy for the treatment of cerebral ischemic stroke.

BACKGROUND: Effective amelioration of neuronal damages in the case of cerebral ischemic stroke (CIS) is essential for the protection of brain tissues and their functional recovery. However, most drugs can not penetrate the blood-brain barrier (BBB), resulting in the poor therapeutic outcomes. RESULTS: In this study, the derivatization and dual targeted delivery technologies were used to actively transport antioxidant melatonin (MLT) into the mitochondria of oxidative stress-damaged cells in brain tissues. A mitochondrial targeting molecule triphenylphosphine (TPP) was conjugated to melatonin (TPP-MLT) to increase the distribution of melatonin in intracellular mitochondria with the push of mitochondrial transmembrane potential. Then, TPP-MLT was encapsulated in dual targeted micelles mediated by TGN peptide (TGNYKALHPHNG) with high affinity for BBB and SHp peptide (CLEVSRKNG) for the glutamate receptor of oxidative stress-damaged neural cells.TGN/SHp/TPP-MLT micelles could effectively scavenge the overproduced ROS to protect neuronal cells from oxidative stress injury during CIS occurrence, as reflected by the improved infarct volume and neurological deficit in CIS model animals. CONCLUSIONS: These promising results showed this stepwise-targeting drug-loaded micelles potentially represent a significant advancement in the precise treatment of CIS.

9-Methylfascaplysin Is a More Potent Aß Aggregation Inhibitor than the Marine-Derived Alkaloid, Fascaplysin, and Produces Nanomolar Neuroprotective Effects in SH-SY5Y Cells.

ß-Amyloid (Aß) is regarded as an important pathogenic target for Alzheimer's disease (AD), the most prevalent neurodegenerative disease. Aß can assemble into oligomers and fibrils, and produce neurotoxicity. Therefore, Aß aggregation inhibitors may have anti-AD therapeutic efficacies. It was found, here, that the marine-derived alkaloid, fascaplysin, inhibits Aß fibrillization in vitro. Moreover, the new analogue, 9-methylfascaplysin, was designed and synthesized from 5-methyltryptamine. Interestingly, 9-methylfascaplysin is a more potent inhibitor of Aß fibril formation than fascaplysin. Incubation of 9-methylfascaplysin with Aß directly reduced Aß oligomer formation. Molecular dynamics simulations revealed that 9-methylfascaplysin might interact with negatively charged residues of Aß42 with polar binding energy. Hydrogen bonds and π⁻π interactions between the key amino acid residues of Aß42 and 9-methylfascaplysin were also suggested. Most importantly, compared with the typical Aß oligomer, Aß modified by nanomolar 9-methylfascaplysin produced less neuronal toxicity in SH-SY5Y cells. 9-Methylfascaplysin appears to be one of the most potent marine-derived compounds that produces anti-Aß neuroprotective effects. Given previous reports that fascaplysin inhibits acetylcholinesterase and induces P-glycoprotein, the current study results suggest that fascaplysin derivatives can be developed as novel anti-AD drugs that possibly act via inhibition of Aß aggregation along with other target mechanisms.

Metal-free synthesis of isatin oximes via radical coupling reactions of oxindoles with t-BuONO in water.

A metal-free method for the synthesis of isatin oximes was developed through the radical coupling reactions of oxindoles with t-BuONO. This protocol provides a practical and environmentally benign method for the construction of C-N bonds in water at room temperature without using any other reagents. The advantages of this strategy are its mild reaction conditions and clean procedure.

The Structure-Activity Relationship between Marine Algae Polysaccharides and Anti-Complement Activity.

In this study, 33 different polysaccharides were prepared to investigate the structure-activity relationships between the polysaccharides, mainly from marine algae, and anti-complement activity in the classical pathway. Factors considered included extraction methods, fractionations, molecular weight, molar ratio of galactose to fucose, sulfate, uronic acid (UA) content, linkage, branching, and the type of monosaccharide. It was shown that the larger the molecular weights, the better the activities. The molar ratio of galactose (Gal) to fucose (Fuc) was a positive factor at a concentration lower than 10 µg/mL, while it had no effect at a concentration more than 10 µg/mL. In addition, sulfate was necessary; however, the sulfate content, the sulfate pattern, linkage and branching had no effect at a concentration of more than 10 µg/mL. Moreover, the type of monosaccharide had no effect. Laminaran and UA fractions had no activity; however, they could reduce the activity by decreasing the effective concentration of the active composition when they were mixed with the active compositions. The effect of the extraction methods could not be determined. Finally, it was observed that sulfated galactofucan showed good anti-complement activity after separation.

A Multi-Responsive Hydrogel Combined With Mild Heat Stimulation Promotes Diabetic Wound Healing by Regulating Inflammatory and Enhancing Angiogenesis.

The repair of diabetic wound still encounters huge challenges, such as disordered inflammatory regulation and impaired neovascularization. Here, a pH/ROS/glucose responsive and photothermal hydrogel is developed for diabetic wound healing. The hydrogel is formed through cross-linkage between phenylboronic acid-modified carboxymethyl chitosan (CMCS-PBA) and oxide dextran (OXD), utilizing Schiff base and phenylboronate ester bonds. Additionally, insulin-like growth factor 1 C domain (IGF-1C) and deferoxamine-loaded polydopamine nanoparticles (D@P) are incorporated into the hydrogel. The hydrogel demonstrates sustained drug release, excellent photo thermal effect, prominent antioxidant, antibacterial and anti-inflammatory activities, desirable mechanical and tissue adhesive properties, enhanced tube formation, and cell migration. Furthermore, the hydrogel combined with mild heat treatment can regulate chronic inflammation by promoting the transformation of macrophages from M1 phenotype to M2 phenotype and enhance angiogenesis by up-regulating the expression levels of angiogenesis-related factors such as hypoxia-inducible factor-1 alpha (HIF-1α), vascular endothelial growth factor (VEGF), CD31, and α-SMA, thus greatly accelerates the wound healing in streptozotocin (STZ)-induced diabetic mice. Therefore, this multi-responsive and multifunctional hydrogel holds potential as a therapeutic strategy for diabetic wounds.

Intramolecular Hydrogen Bonding Rigidifying Flexible Bridge for Solution- and Vacuum-Processed TSCT-TADF Emitters.

To realize strong donor-acceptor face-to-face stacking for efficient through-space charge transfer-type thermally activated delayed fluorescence, a conceptually new design strategy is proposed to couple flexible bridges with adequate rigidity via built-in intramolecular hydrogen bonds (IHBs). The resulting emitter ACE-CN has a planarized benzyl methyl ether bridge self-anchored by the C-H···O IHB and shows a high photoluminescence quantum efficiency of 93%. The solution- and vacuum-processed devices exhibited high external quantum efficiencies of 11.8% and 24.7%, respectively.

Rational molecular design converting fascaplysin derivatives to potent broad-spectrum inhibitors against bacterial pathogens via targeting FtsZ.

The filamentous temperature-sensitive mutant Z protein (FtsZ), a key player in bacterial cell division machinery, emerges as an attractive target to tackle the plight posed by the ever growing antibiotic resistance over the world. Therefore in this regard, agents with scaffold diversities and broad-spectrum antibacterial activity against Gram-positive and Gram-negative pathogens are highly needed. In this study, a new class of marine-derived fascaplysin derivatives has been designed and synthesized by Suzuki-Miyaura cross-coupling. Some compounds exhibited potent bactericidal activities against a panel of Gram-positive (MIC = 0.024-6.25 µg/mL) and Gram-negative (MIC = 1.56-12.5 µg/mL) bacteria including methicillin-resistant S. aureus (MRSA). They exerted their effects by dual action mechanism via disrupting the integrity of the bacterial cell membrane and targeting FtsZ protein. These compounds stimulated polymerization of FtsZ monomers and bundling of the polymers, and stabilized the resulting polymer network, thus leading to the dysfunction of FtsZ in cell division. In addition, these agents showed negligible hemolytic activity and low cytotoxicity to mammalian cells. The studies on docking and molecular dynamics simulations suggest that these inhibitors bind to the hydrophilic inter-domain cleft of FtsZ protein and the insights obtained in this study would facilitate the development of potential drugs with broad-spectrum bioactivities.

A dye-quenched/sensitized switching upconversion nanoprobe for high-contrast mapping of the pH-related tumor microenvironment.

Nanoprobes based on lanthanide-doped upconversion nanoparticles (UCNPs) exhibit promising potential in bioimaging and biosensing due to their unique optical properties. However, conventional UCNP nanoprobes based on the dye quenching effect are still limited in biosensing due to their low upconversion efficiency. The advent of dye-sensitized upconversion has resulted in nanoprobes with significantly enhanced efficiency; however, these still suffer from a high initial emissive background. In view of this, herein, we have constructed a dye-quenched/sensitized switching upconversion nanoprobe for high-contrast imaging of the pH-related tumor microenvironment. Under normal conditions, the luminescence of the nanoprobe at 540 nm (UCL540) was significantly quenched by the employed dye. Upon being triggered by an acid, the dye would switch to its fluorescent form to sensitize the luminescence of UCNPs, affording a significant enhancement of UCL540. The switching from dye-quenched UCL to dye-sensitized UCL jointly enables the detection of a high signal-to-background ratio (high up to 50), allowing for high-contrast mapping of the tumor specific acidic microenvironment in vivo. We believe that this nanoplatform holds considerable promise for acid-related sensing.

Post-synthesis of covalent organic frameworks as a hydrophilic platform for specific detection of egg ovalbumin under physiological pH.

Ovalbumin (OVA) is an important protein source in our daily life. Unfortunately, the food safety problem has become more and more serious, such as protein allergy and contaminated protein. Therefore, it is necessary to detect vital proteins efficiently and rapidly. Mass spectrometry (MS) is a powerful tool for the detection of proteins. Herein, dual amino acids functionalized covalent organic frameworks containing disulfide covalent bonds (COF@SS@GC, where G is glutathione and C is cysteine) were facilely prepared for OVA enrichment through hydrophilic interaction liquid chromatography (HILIC) under physiological pH. The results showed that COF@SS@GC had displayed sensitive detection (0.1 fmol), good selectivity (OVA: BSA = 1:100), adsorption capacity (311 mg/g), stability, reproducibility, linearity, LOQ level (42 µg/mL) and recovery ratio (64.83 %) for OVA. COF@SS@GC also demonstrated satisfactory purification ability in the enrichment of egg white, indicating that COF@SS@GC had great potential in the enrichment of protein from complex samples.

Natural Polymer-Based Hydrogels: From Polymer to Biomedical Applications.

Hydrogels prepared from natural polymer have attracted extensive attention in biomedical fields such as drug delivery, wound healing, and regenerative medicine due to their good biocompatibility, degradability, and flexibility. This review outlines the commonly used natural polymer in hydrogel preparation, including cellulose, chitosan, collagen/gelatin, alginate, hyaluronic acid, starch, guar gum, agarose, and dextran. The polymeric structure and process/synthesis of natural polymers are illustrated, and natural polymer-based hydrogels including the hydrogel formation and properties are elaborated. Subsequently, the biomedical applications of hydrogels based on natural polymer in drug delivery, tissue regeneration, wound healing, and other biomedical fields are summarized. Finally, the future perspectives of natural polymers and hydrogels based on them are discussed. For natural polymers, novel technologies such as enzymatic and biological methods have been developed to improve their structural properties, and the development of new natural-based polymers or natural polymer derivatives with high performance is still very important and challenging. For natural polymer-based hydrogels, novel hydrogel materials, like double-network hydrogel, multifunctional composite hydrogels, and hydrogel microrobots have been designed to meet the advanced requirements in biomedical applications, and new strategies such as dual-cross-linking, microfluidic chip, micropatterning, and 3D/4D bioprinting have been explored to fabricate advanced hydrogel materials with designed properties for biomedical applications. Overall, natural polymeric hydrogels have attracted increasing interest in biomedical applications, and the development of novel natural polymer-based materials and new strategies/methods for hydrogel fabrication are highly desirable and still challenging.

Phosphonate-Functionalized Ionic Liquid Gel Polymer Electrolyte with High Safety for Dendrite-Free Lithium Metal Batteries.

The conventional lithium-ion battery technology relies on the liquid carbonate-based electrolyte solution, which causes excessive side reactions, serious risk of electrolyte leakage, high flammability, and significant safety hazards. In this work, phosphonate-functionalized imidazolium ionic liquid (PFIL) is synthesized and used as a gel polymer electrolyte (GPE) to replace the organic carbonate-based electrolyte solution. The as-prepared ionic liquid-based gel polymer electrolyte (IL-GPE) shows low crystallinity, flame retardance, and excellent electrochemical performance. Thanks to the fast double channel transport of lithium ions in the IL-GPE electrolyte, a high ionic conductivity of 0.48 mS cm-1 and a lithium-ion transference number of 0.37 are exhibited. Symmetrical lithium cells with IL-GPE retain stable cycling even after 3000 h under 0.1 mA cm-2. IL-GPE exhibits good compatibility toward lithium metal, yielding excellent long-term electrochemical kinetic stability. IL-GPE induces the formation of a uniform and robust SEI layer, inhibiting the growth of lithium dendrites and improving the rate performance and cycle stability. Furthermore, Li/LiFePO4 cells exhibit a specific capacity of 63 mA h g-1 after 150 cycles at 5.0 C, with a capacity retention of 90.2%. It is foreseen that this GPE is a promising candidate to enhance the safety of high-performance lithium metal batteries.

Chitosan-based injectable hydrogels with dual glucose sensors for precise control of insulin release and diabetes mellitus therapy.

Chitosan-based injectable hydrogels were designed and fabricated through the dynamic crosslinking of dual-reversible covalent bonds (imine and phenylboronate ester) for precise insulin release. The hydrogels contain dual glucose-sensors/responsive elements, featuring high sensitivity and rapid responsiveness to glucose level variation in cumulative and half-hourly pulsed insulin release. The hydrogels demonstrated improved cytocompatibility against HSF cells and histological long-term analysis of tissue after implantation. Evaluation of the glycemic control ability in STZ-induced hyperglycemic mice revealed that the hydrogel system showed excellent glycemic control ability in the glucose tolerance test and maintained blood glucose levels in a normal range for up to 11 days after a single administration. Thus, the hydrogel system showed applicable potential in insulin replacement therapy for diabetes mellitus.

Design and synthesis of fascaplysin derivatives as inhibitors of FtsZ with potent antibacterial activity and mechanistic study.

The increase in antibiotic resistance has made it particularly urgent to develop new antibiotics with novel antibacterial mechanisms. Inhibition of bacterial cell division by disrupting filamentous temperature-sensitive mutant Z (FtsZ) function is an effective and promising approach. A series of novel fascaplysin derivatives with tunable hydrophobicity were designed and synthesized here. The in vitro bioactivity assessment revealed that these compounds could inhibit the tested Gram-positive bacteria including methicillin-resistant S. aureus (MRSA) (MIC = 0.049-25 µg/mL), B. subtilis (MIC = 0.024-12.5 µg/mL) and S. pneumoniae (MIC = 0.049-50 µg/mL). Among them, compounds B3 (MIC = 0.098 µg/mL), B6 (MIC = 0.098 µg/mL), B8 (MIC = 0.049 µg/mL) and B16 (MIC = 0.098 µg/mL) showed the best bactericidal activities against MRSA and no significant tendency to trigger bacterial resistance as well as rapid bactericidal properties. The cell surface integrity of bacteria was significantly disrupted by hydrophobic tails of fascaplysin derivatives. Further studies revealed that these highly active amphiphilic compounds showed low hemolytic activity and cytotoxicity to mammalian cells. Preliminary mechanistic exploration suggests that B3, B6, B8 and B16 are potent FtsZ inhibitors to promote FtsZ polymerization and inhibit GTPase activity of FtsZ, leading to the death of bacterial cells by inhibiting bacterial division. Molecular docking simulations and structure-activity relationship (SAR) study reveal that appropriate increase in the hydrophobicity of fascaplysin derivatives and the addition of additional hydrogen bonds facilitated their binding to FtsZ proteins. These amphiphilic fascaplysin derivatives could serve as a novel class of FtsZ inhibitors, which not only gives new prospects for the application of compounds containing this skeleton but also provides new ideas for the discovery of new antibiotics.

Magnetic mesoporous silica nanoparticles modified by phosphonate functionalized ionic liquid for selective enrichment of phosphopeptides.

In this study, new magnetic nanoparticles (denotated as Fe3O4@mSiO2-PFIL-Ti4+) have been prepared by immobilizing titanium ions with phosphonate functionalized ionic liquid (PFIL) on the wall of core-shell structured mesoporous nanomaterials. The resulting nanoparticles possess large specific surface area, strong hydrophilicity and fast magnetic response. The composites can capture traces of phosphopeptides from the tryptic ß-casein digest (0.08 fmol), a digest mixture of ß-casein and BSA (1 : 10 000, molar ratio) as well as a blend of ß-casein digest and a great quantity of phosphorylated protein (ß-casein) and non-phosphorylated protein (BSA) (1 : 2000 : 2000, mass ratio), respectively, showing excellent sensitivity, selectivity and size exclusion ability. Additionally, Fe3O4@mSiO2-PFIL-Ti4+ shows excellent steadiness and can be reused at least 12 times. Moreover, this material was successfully applied to enrich endogenous phosphopeptides from complex bio-samples, including human saliva and serum.

Fascaplysin derivatives binding to DNA via unique cationic five-ring coplanar backbone showed potent antimicrobial/antibiofilm activity against MRSA in vitro and in vivo.

Methicillin-resistant Staphylococcus aureus (MRSA) is considered as one of the most dangerous clinical pathogens. Biofilms forming ability of MRSA is also a major cause of drug resistance. Hence, it is in urgent need to develop novel antibacterial/antibiofilm drugs. Fascaplysin with a unique cationic five-ring coplanar backbone is emerging as a potential antibacterial compound. In this study, aiming at developing novel and more effective agents, a series of fascaplysin derivatives and their corresponding ß-carboline precursors have been synthesized. Then their antibacterial/antibiofilm activity and mechanisms against MRSA were investigated for the first time. The results showed that most fascaplysins rather than ß-carboline precursors exhibit superior antimicrobial activity against MRSA ATCC43300, demonstrating the important role of cationic five-ring coplanar backbone playing in antibacterial activity. Among them, 14 and 18 are the most potent compounds with MIC value of 0.098 µg/ml (10-fold lower than vancomycin), and 18 featuring the lowest toxicity. Subsequent mechanisms exploration indicates that 18 has relatively stronger ability to destroy bacterial cell wall and membrane, higher binding affinity to bacterial genomic DNA. Molecular docking study revealed that besides the key role of cationic five-ring coplanar backbone, introduction of N-aryl amide at 9-position of fascaplysin promoted the combination of compound 18 and DNA via additional π-π stacking and hydrogen bonding of the naphthyl group. Moreover, fascaplysins could inhibit MRSA biofilm formation in vitro and bacterial infection in vivo. All these results illustrate that fascaplysin derivative 18 is a strong and safe multi-target antibacterial agent, which makes it an attractive candidate for the treatment of MRSA and its biofilm infections.

Superhydrophilic nanocomposite adsorbents modified via nitrogen-rich phosphonate-functionalized ionic liquid linkers: enhanced phosphopeptide enrichment and phosphoproteome analysis of tau phosphorylation in the hippocampal lysate of Alzheimer's transgenic mice.

In this study, new graphene-based IMAC nanocomposites for phosphopeptide enrichment were prepared according to the guideline of our new design strategy. Superhydrophilic polyethyleneimine (PEI) was introduced, to which a phosphonate-functionalized ionic liquid (PFIL) was covalently bound, to form superhydrophilic and cationic surface layers with high densities of nitrogen atoms, phosphonate functional groups, and high-loading metal ions. Due to the combined features of superhydrophilicity, flexibility, highly dense metal binding sites, large surface area and excellent size-exclusion effect, the fabricated nanocomposite G@mSiO2@PEI-PFIL-Ti4+ exhibits superior detection sensitivity to enrich phosphopeptides (tryptic ß-casein digest, 0.1 fmol), and extraordinary enrichment specificity to enrich phosphopeptides from a digest mixture of ß-casein and bovine serum albumin (BSA) (molar ratio, 1 : 12 000). The excellent size-exclusion effect was also observed, and 27 endogenous phosphopeptides were identified in human saliva. All these results could be attributed to the unique superhydrophilic nanocomposite structure with a high density of a cationic linker modified with phosphonate functionality. Moreover, G@mSiO2@PEI-PFIL-Ti4+ adsorbents were used to extract phosphopeptides from the tryptic digests of hippocampal lysates for quantitative phosphoproteome analysis. The preliminary results indicate that 1649 phosphoproteins, 3286 phosphopeptides and 4075 phosphorylation sites were identified. A total of 13 Alzheimer's disease (AD)-related phosphopeptides within tau proteins were detected with a wide coverage from p-Thr111 to p-Ser404, in which the amounts of some phoshopeptides at certain sites in AD transgenic mice were found statistically higher than those in wild type littermates. Besides, phosphorylated neurofilament heavy chains, a potential biomarker for amyotrophic lateral sclerosis and traumatic brain injury, were also identified. Finally, the adsorbent was applied to human cerebrospinal fluid (CSF) and blood samples. 5 unique phosphopeptides of neuroendocrine specific VGF were identified in the CSF, while many phosphopeptides originated from the nervous system were found in the blood sample. All these results suggest that our new IMAC materials exhibit unbiased enrichment ability with superior detection sensitivity and specificity, allowing the global phosphoproteome analysis of complicated biological samples more convincible and indicating the potential use in disease diagnosis.

Rose Bengal inhibits ß-amyloid oligomers-induced tau hyperphosphorylation via acting on Akt and CDK5 kinases.

RATIONALE: Tau hyperphosphorylation and aggregation is considered as a main pathological mechanism underlying Alzheimer's disease (AD). Rose Bengal (RB) is a synthetic dye used for disease diagnosis, which was reported to inhibit tau toxicity via inhibiting tau aggregation in Drosophila. However, it was unknown if RB could produce anti-AD effects in rodents. OBJECTIVES: The research aimed to investigate if and how RB could prevent ß-amyloid (Aß) oligomers-induced tau hyperphosphorylation in rodents. METHODS AND RESULTS: RB was tested in vitro (0.3-1 µM) and prevented Aß oligomers-induced tau hyperphosphorylation in PC12 cells. Moreover, RB (10-30 mg/kg, i.p.) effectively attenuated cognitive impairments induced by Aß oligomers in mice. Western blotting analysis demonstrated that RB significantly increased the expression of pSer473-Akt, pSer9-glycogen synthase kinase-3ß (GSK3ß) and reduced the expression of cyclin-dependent kinase 5 (CDK5) both in vitro and in vivo. Molecular docking analysis suggested that RB might directly interact with GSK3ß and CDK5 by acting on ATP binding sites. Gene Ontology enrichment analysis indicated that RB might act on protein phosphorylation pathways to inhibit tau hyperphosphorylation. CONCLUSIONS: RB was shown to inhibit tau neurotoxicity at least partially via inhibiting the activity of GSK3ß and CDK5, which is a novel neuroprotective mechanism besides the inhibition of tau aggregation. As tau hyperphosphorylation is an important target for AD therapy, this study also provided support for investigating the drug repurposing of RB as an anti-AD drug candidate.