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Protection against β-amyloid-induced synaptic and memory impairments via altering β-amyloid assembly by bis(heptyl)-cognitin.

Chang L, Cui W, Yang Y, Xu S, Zhou W, Fu H, Hu S, Mak S, Hu J, Wang Q, Ma VP, Choi TC, Ma ED, Tao L, Pang Y, Rowan MJ, Anwyl R, Han Y, Wang Q - Sci Rep (2015)

Bottom Line: Molecular docking analysis further suggested that bis(heptyl)-cognitin presumably interacted with the hydrophobic pockets of Aβ, which confers stabilizing powers and assembly alteration effects on Aβ.Most importantly, bis(heptyl)-cognitin significantly reduced cognitive impairments induced by intra-hippocampal infusion of Aβ oligomers in mice.These results clearly demonstrated how dimeric agents prevent Aβ oligomers-induced synaptic and memory impairments, and offered a strong support for the beneficial therapeutic effects of bis(heptyl)-cognitin in the treatment of AD.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, Ningbo Key Laboratory of Behavioral Neuroscience, Zhejiang Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University. Ningbo 315211, China.

ABSTRACT
β-amyloid (Aβ) oligomers have been closely implicated in the pathogenesis of Alzheimer's disease (AD). We found, for the first time, that bis(heptyl)-cognitin, a novel dimeric acetylcholinesterase (AChE) inhibitor derived from tacrine, prevented Aβ oligomers-induced inhibition of long-term potentiation (LTP) at concentrations that did not interfere with normal LTP. Bis(heptyl)-cognitin also prevented Aβ oligomers-induced synaptotoxicity in primary hippocampal neurons. In contrast, tacrine and donepezil, typical AChE inhibitors, could not prevent synaptic impairments in these models, indicating that the modification of Aβ oligomers toxicity by bis(heptyl)-cognitin might be attributed to a mechanism other than AChE inhibition. Studies by using dot blotting, immunoblotting, circular dichroism spectroscopy, and transmission electron microscopy have shown that bis(heptyl)-cognitin altered Aβ assembly via directly inhibiting Aβ oligomers formation and reducing the amount of preformed Aβ oligomers. Molecular docking analysis further suggested that bis(heptyl)-cognitin presumably interacted with the hydrophobic pockets of Aβ, which confers stabilizing powers and assembly alteration effects on Aβ. Most importantly, bis(heptyl)-cognitin significantly reduced cognitive impairments induced by intra-hippocampal infusion of Aβ oligomers in mice. These results clearly demonstrated how dimeric agents prevent Aβ oligomers-induced synaptic and memory impairments, and offered a strong support for the beneficial therapeutic effects of bis(heptyl)-cognitin in the treatment of AD.

No MeSH data available.


Related in: MedlinePlus

Bis(heptyl)-cognitin inhibits Aβ1-42 oligomers formation, and reduces the amount of preformed Aβ1-42 oligomers.(A) Bis(heptyl)-cognitin inhibits Aβ1-42 oligomers formation. 50 μM disassembled (HFIP-pretreated) Aβ1-42 was incubated with various agents as indicated for 48 hours at 4 °C. Aβ1-42 solution was then centrifuged at 14000 g for 10 min, the supernatant was spotted onto the membrane. Then the membrane was immunoblotted with anti-oligomer antibody (A11) or anti-Aβ1-17 antibody (6E10). (B) Statistic analysis of relative density of A11 dots in each treatment group. Data were expressed as the ratio to OD values of the corresponding controls. Data, expressed as percentage of control, were the mean ± SEM of three separate experiments; **p < 0.01 versus Aβ1-42 group (ANOVA and Dunnett’s test). (C) Bis(heptyl)-cognitin reduces the amount of Aβ1-42 oligomers. 50 μM disassembled Aβ1-42 was incubated with various agents as indicated for 48 hours at 4 °C. Aβ1-42 solution was then centrifuged at 14000 g for 10 min. The supernatant was electrophoresed at 100 V on a 15% Tris-Tricine SDS gel and probed with anti-Aβ1-17 antibody (6E10). M, monomer; D, dimer; T, trimer; H, hexamer; O, medium-size oligomer. Assemblies ranging from dimers to medium-size oligomer were recognized as Aβ oligomers. (D) Bis(heptyl)-cognitin reduces the amount of preformed Aβ1-42 oligomers. 50 μM disassembled Aβ1-42 was incubated for 48 hours at 4 °C, and then treated with various agents as indicated for 2 hours at 4 °C. Aβ1-42 solution was then centrifuged at 14000 g for 10 min, the supernatant was spotted onto the membrane. Then the membrane was immunoblotted with anti-oligomer antibody (A11) or anti-Aβ1-17 antibody (6E10). (E) Statistic analysis of relative density of A11 dots in each treatment group. Data were expressed as the ratio to OD values of the corresponding controls. Data, expressed as percentage of control, were the mean ± SEM of three separate experiments; *p < 0.05 and **p < 0.01 versus pre-formed Aβ1-42 oligomers group (ANOVA and Dunnett’s test).
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f4: Bis(heptyl)-cognitin inhibits Aβ1-42 oligomers formation, and reduces the amount of preformed Aβ1-42 oligomers.(A) Bis(heptyl)-cognitin inhibits Aβ1-42 oligomers formation. 50 μM disassembled (HFIP-pretreated) Aβ1-42 was incubated with various agents as indicated for 48 hours at 4 °C. Aβ1-42 solution was then centrifuged at 14000 g for 10 min, the supernatant was spotted onto the membrane. Then the membrane was immunoblotted with anti-oligomer antibody (A11) or anti-Aβ1-17 antibody (6E10). (B) Statistic analysis of relative density of A11 dots in each treatment group. Data were expressed as the ratio to OD values of the corresponding controls. Data, expressed as percentage of control, were the mean ± SEM of three separate experiments; **p < 0.01 versus Aβ1-42 group (ANOVA and Dunnett’s test). (C) Bis(heptyl)-cognitin reduces the amount of Aβ1-42 oligomers. 50 μM disassembled Aβ1-42 was incubated with various agents as indicated for 48 hours at 4 °C. Aβ1-42 solution was then centrifuged at 14000 g for 10 min. The supernatant was electrophoresed at 100 V on a 15% Tris-Tricine SDS gel and probed with anti-Aβ1-17 antibody (6E10). M, monomer; D, dimer; T, trimer; H, hexamer; O, medium-size oligomer. Assemblies ranging from dimers to medium-size oligomer were recognized as Aβ oligomers. (D) Bis(heptyl)-cognitin reduces the amount of preformed Aβ1-42 oligomers. 50 μM disassembled Aβ1-42 was incubated for 48 hours at 4 °C, and then treated with various agents as indicated for 2 hours at 4 °C. Aβ1-42 solution was then centrifuged at 14000 g for 10 min, the supernatant was spotted onto the membrane. Then the membrane was immunoblotted with anti-oligomer antibody (A11) or anti-Aβ1-17 antibody (6E10). (E) Statistic analysis of relative density of A11 dots in each treatment group. Data were expressed as the ratio to OD values of the corresponding controls. Data, expressed as percentage of control, were the mean ± SEM of three separate experiments; *p < 0.05 and **p < 0.01 versus pre-formed Aβ1-42 oligomers group (ANOVA and Dunnett’s test).

Mentions: In order to test whether the anti-Aβ oligomers-induced synaptic impairments effects of bis(heptyl)-cognitin were related to the alteration of Aβ assembly, Aβ1-42 oligomerization assay and dot blotting analysis were used. We dissolved 50 μM Aβ1-42 in HFIP to reconstitute a “seedless” monomer and then incubated it with bis(heptyl)-cognitin in an oligomer formation protocol1. The resulting oligomers-enriched supernatants were analyzed by immunoblotting and dot blotting analysis with an oligomer-specific antibody A11 and a general Aβ antibody 6E10. It was found that bis(heptyl)-cognitin (1-10 μM) substantially inhibited the formation of Aβ1-42 oligomers (Fig. 4A,B).


Protection against β-amyloid-induced synaptic and memory impairments via altering β-amyloid assembly by bis(heptyl)-cognitin.

Chang L, Cui W, Yang Y, Xu S, Zhou W, Fu H, Hu S, Mak S, Hu J, Wang Q, Ma VP, Choi TC, Ma ED, Tao L, Pang Y, Rowan MJ, Anwyl R, Han Y, Wang Q - Sci Rep (2015)

Bis(heptyl)-cognitin inhibits Aβ1-42 oligomers formation, and reduces the amount of preformed Aβ1-42 oligomers.(A) Bis(heptyl)-cognitin inhibits Aβ1-42 oligomers formation. 50 μM disassembled (HFIP-pretreated) Aβ1-42 was incubated with various agents as indicated for 48 hours at 4 °C. Aβ1-42 solution was then centrifuged at 14000 g for 10 min, the supernatant was spotted onto the membrane. Then the membrane was immunoblotted with anti-oligomer antibody (A11) or anti-Aβ1-17 antibody (6E10). (B) Statistic analysis of relative density of A11 dots in each treatment group. Data were expressed as the ratio to OD values of the corresponding controls. Data, expressed as percentage of control, were the mean ± SEM of three separate experiments; **p < 0.01 versus Aβ1-42 group (ANOVA and Dunnett’s test). (C) Bis(heptyl)-cognitin reduces the amount of Aβ1-42 oligomers. 50 μM disassembled Aβ1-42 was incubated with various agents as indicated for 48 hours at 4 °C. Aβ1-42 solution was then centrifuged at 14000 g for 10 min. The supernatant was electrophoresed at 100 V on a 15% Tris-Tricine SDS gel and probed with anti-Aβ1-17 antibody (6E10). M, monomer; D, dimer; T, trimer; H, hexamer; O, medium-size oligomer. Assemblies ranging from dimers to medium-size oligomer were recognized as Aβ oligomers. (D) Bis(heptyl)-cognitin reduces the amount of preformed Aβ1-42 oligomers. 50 μM disassembled Aβ1-42 was incubated for 48 hours at 4 °C, and then treated with various agents as indicated for 2 hours at 4 °C. Aβ1-42 solution was then centrifuged at 14000 g for 10 min, the supernatant was spotted onto the membrane. Then the membrane was immunoblotted with anti-oligomer antibody (A11) or anti-Aβ1-17 antibody (6E10). (E) Statistic analysis of relative density of A11 dots in each treatment group. Data were expressed as the ratio to OD values of the corresponding controls. Data, expressed as percentage of control, were the mean ± SEM of three separate experiments; *p < 0.05 and **p < 0.01 versus pre-formed Aβ1-42 oligomers group (ANOVA and Dunnett’s test).
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Related In: Results  -  Collection

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Show All Figures
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f4: Bis(heptyl)-cognitin inhibits Aβ1-42 oligomers formation, and reduces the amount of preformed Aβ1-42 oligomers.(A) Bis(heptyl)-cognitin inhibits Aβ1-42 oligomers formation. 50 μM disassembled (HFIP-pretreated) Aβ1-42 was incubated with various agents as indicated for 48 hours at 4 °C. Aβ1-42 solution was then centrifuged at 14000 g for 10 min, the supernatant was spotted onto the membrane. Then the membrane was immunoblotted with anti-oligomer antibody (A11) or anti-Aβ1-17 antibody (6E10). (B) Statistic analysis of relative density of A11 dots in each treatment group. Data were expressed as the ratio to OD values of the corresponding controls. Data, expressed as percentage of control, were the mean ± SEM of three separate experiments; **p < 0.01 versus Aβ1-42 group (ANOVA and Dunnett’s test). (C) Bis(heptyl)-cognitin reduces the amount of Aβ1-42 oligomers. 50 μM disassembled Aβ1-42 was incubated with various agents as indicated for 48 hours at 4 °C. Aβ1-42 solution was then centrifuged at 14000 g for 10 min. The supernatant was electrophoresed at 100 V on a 15% Tris-Tricine SDS gel and probed with anti-Aβ1-17 antibody (6E10). M, monomer; D, dimer; T, trimer; H, hexamer; O, medium-size oligomer. Assemblies ranging from dimers to medium-size oligomer were recognized as Aβ oligomers. (D) Bis(heptyl)-cognitin reduces the amount of preformed Aβ1-42 oligomers. 50 μM disassembled Aβ1-42 was incubated for 48 hours at 4 °C, and then treated with various agents as indicated for 2 hours at 4 °C. Aβ1-42 solution was then centrifuged at 14000 g for 10 min, the supernatant was spotted onto the membrane. Then the membrane was immunoblotted with anti-oligomer antibody (A11) or anti-Aβ1-17 antibody (6E10). (E) Statistic analysis of relative density of A11 dots in each treatment group. Data were expressed as the ratio to OD values of the corresponding controls. Data, expressed as percentage of control, were the mean ± SEM of three separate experiments; *p < 0.05 and **p < 0.01 versus pre-formed Aβ1-42 oligomers group (ANOVA and Dunnett’s test).
Mentions: In order to test whether the anti-Aβ oligomers-induced synaptic impairments effects of bis(heptyl)-cognitin were related to the alteration of Aβ assembly, Aβ1-42 oligomerization assay and dot blotting analysis were used. We dissolved 50 μM Aβ1-42 in HFIP to reconstitute a “seedless” monomer and then incubated it with bis(heptyl)-cognitin in an oligomer formation protocol1. The resulting oligomers-enriched supernatants were analyzed by immunoblotting and dot blotting analysis with an oligomer-specific antibody A11 and a general Aβ antibody 6E10. It was found that bis(heptyl)-cognitin (1-10 μM) substantially inhibited the formation of Aβ1-42 oligomers (Fig. 4A,B).

Bottom Line: Molecular docking analysis further suggested that bis(heptyl)-cognitin presumably interacted with the hydrophobic pockets of Aβ, which confers stabilizing powers and assembly alteration effects on Aβ.Most importantly, bis(heptyl)-cognitin significantly reduced cognitive impairments induced by intra-hippocampal infusion of Aβ oligomers in mice.These results clearly demonstrated how dimeric agents prevent Aβ oligomers-induced synaptic and memory impairments, and offered a strong support for the beneficial therapeutic effects of bis(heptyl)-cognitin in the treatment of AD.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, Ningbo Key Laboratory of Behavioral Neuroscience, Zhejiang Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University. Ningbo 315211, China.

ABSTRACT
β-amyloid (Aβ) oligomers have been closely implicated in the pathogenesis of Alzheimer's disease (AD). We found, for the first time, that bis(heptyl)-cognitin, a novel dimeric acetylcholinesterase (AChE) inhibitor derived from tacrine, prevented Aβ oligomers-induced inhibition of long-term potentiation (LTP) at concentrations that did not interfere with normal LTP. Bis(heptyl)-cognitin also prevented Aβ oligomers-induced synaptotoxicity in primary hippocampal neurons. In contrast, tacrine and donepezil, typical AChE inhibitors, could not prevent synaptic impairments in these models, indicating that the modification of Aβ oligomers toxicity by bis(heptyl)-cognitin might be attributed to a mechanism other than AChE inhibition. Studies by using dot blotting, immunoblotting, circular dichroism spectroscopy, and transmission electron microscopy have shown that bis(heptyl)-cognitin altered Aβ assembly via directly inhibiting Aβ oligomers formation and reducing the amount of preformed Aβ oligomers. Molecular docking analysis further suggested that bis(heptyl)-cognitin presumably interacted with the hydrophobic pockets of Aβ, which confers stabilizing powers and assembly alteration effects on Aβ. Most importantly, bis(heptyl)-cognitin significantly reduced cognitive impairments induced by intra-hippocampal infusion of Aβ oligomers in mice. These results clearly demonstrated how dimeric agents prevent Aβ oligomers-induced synaptic and memory impairments, and offered a strong support for the beneficial therapeutic effects of bis(heptyl)-cognitin in the treatment of AD.

No MeSH data available.


Related in: MedlinePlus