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Induction of autophagy by a novel small molecule improves aβ pathology and ameliorates cognitive deficits.

Chu C, Zhang X, Ma W, Li L, Wang W, Shang L, Fu P - PLoS ONE (2013)

Bottom Line: GTM-1 modulates autophagy in an Akt-independent and mTOR-independent manner.In addition, we demonstrated that GTM-1 enhances autophagy clearance and reverses the downregulation of autophagy flux by thapsigargin and asparagine.Furthermore, administration of GTM-1 attenuated Aβ pathology and ameliorated cognitive deficits in AD mice.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, The First People's Hospital of Yangzhou, Jiang Su, PR China.

ABSTRACT
Growing evidence has demonstrated a neuroprotective role of autophagy in Alzheimer's disease (AD). Thus, autophagy has been regarded as a potential therapeutic target, attracting increasing interest in pharmaceutical autophagy modulation by small molecules. We designed a two-cycle screening strategy on the basis of imaging high-throughout screening (HTS) and cellular toxicity assay, and have identified a novel autophagy inducer known as GTM-1. We further showed that GTM-1 exhibits dual activities, such as autophagy induction and antagonism against Aβ-oligomer toxicity. GTM-1 modulates autophagy in an Akt-independent and mTOR-independent manner. In addition, we demonstrated that GTM-1 enhances autophagy clearance and reverses the downregulation of autophagy flux by thapsigargin and asparagine. Furthermore, administration of GTM-1 attenuated Aβ pathology and ameliorated cognitive deficits in AD mice.

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Related in: MedlinePlus

GTM-1 rescues Aβ and Tau pathology in AD mice.A–B, GTM-1 (6 mg/kg/day) or vehicle (VEH) was administered to five-month-old 3XTg-AD mice daily for 8 weeks. The average body weight (A) and total food consumed for 8 weeks (B) was recorded. C–D, F–G, 5-month-old 3XTg-AD mice (C, D) or 15-month-old 3XTg-AD mice (F, G) were treated with GTM-1 (3 mg/kg/day) daily for 8 weeks. The insoluble and soluble Aβ42 (C, D) levels were measured using a sandwich ELISA. E, Brain proteins were obtained from 8 different 3xTg-AD mice treated with GTM-1 and 8 different 3xTg-AD mice treated with vehicle after 8 weeks of treatment. The endogenous expression of APP, C99 and C83 were assessed using western blotting analyses. CT (control treatment) mice fed with a normal (vehicle) diet. Stars indicate significant differences between the model group and control or treatment groups for that time point. *P<0.05, **P<0.01. F, Five-month-old 3XTg-AD mice were treated with GTM-1 (6 mg/kg/day) or vehicle (PC, positive control) for 2 months. The brain sample from non-Tg mice with the same generic background was used as a negative control (NC). Soluble fractions extracted from brain samples were applied onto Hybond C-extra membrane. Next, the bound oligomeric Aβ and mono-Aβ on the membranes were detected using mono-Aβ specific antibodies, and oligomer-specific antibodies, respectively. Commercial soluble Aβ monomers and oligomeric Aβs produced from the monomer were spotted as indicated and used as another control. G, Densitometric analysis of the immune dot-blot experiments was performed using a high-resolution scanner, and the average intensity of each group was normalized using the average PC result. H, Five-month-old 3XTg-AD mice were treated as previously. Representative sections obtained from the brains of mice treated with GTM-1 and vehicle were immunostained using an Aβ-specific antibody.
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pone-0065367-g005: GTM-1 rescues Aβ and Tau pathology in AD mice.A–B, GTM-1 (6 mg/kg/day) or vehicle (VEH) was administered to five-month-old 3XTg-AD mice daily for 8 weeks. The average body weight (A) and total food consumed for 8 weeks (B) was recorded. C–D, F–G, 5-month-old 3XTg-AD mice (C, D) or 15-month-old 3XTg-AD mice (F, G) were treated with GTM-1 (3 mg/kg/day) daily for 8 weeks. The insoluble and soluble Aβ42 (C, D) levels were measured using a sandwich ELISA. E, Brain proteins were obtained from 8 different 3xTg-AD mice treated with GTM-1 and 8 different 3xTg-AD mice treated with vehicle after 8 weeks of treatment. The endogenous expression of APP, C99 and C83 were assessed using western blotting analyses. CT (control treatment) mice fed with a normal (vehicle) diet. Stars indicate significant differences between the model group and control or treatment groups for that time point. *P<0.05, **P<0.01. F, Five-month-old 3XTg-AD mice were treated with GTM-1 (6 mg/kg/day) or vehicle (PC, positive control) for 2 months. The brain sample from non-Tg mice with the same generic background was used as a negative control (NC). Soluble fractions extracted from brain samples were applied onto Hybond C-extra membrane. Next, the bound oligomeric Aβ and mono-Aβ on the membranes were detected using mono-Aβ specific antibodies, and oligomer-specific antibodies, respectively. Commercial soluble Aβ monomers and oligomeric Aβs produced from the monomer were spotted as indicated and used as another control. G, Densitometric analysis of the immune dot-blot experiments was performed using a high-resolution scanner, and the average intensity of each group was normalized using the average PC result. H, Five-month-old 3XTg-AD mice were treated as previously. Representative sections obtained from the brains of mice treated with GTM-1 and vehicle were immunostained using an Aβ-specific antibody.

Mentions: Cellular experiments in SH-SY5Y and MC65 cells demonstrated that GTM-1 had no toxic effect on neurons (Fig. 3C, 3D). To further evaluate the toxicity of GTM-1, the effects of GTM-1 on animal body weight were measured in WT mice. The body weights of the mice were measured at different time points during the 8-week treatment period, and the results are shown as weekly averages for groups of vehicle (VEH)- and GTM-1 (6 mg/Kg/day)-treated mice. As shown in Figure 5A and 5B, the body weights of VEH- and GTM-1 (6 mg/Kg/day)-treated animals remained similar during most of the treatment period. Moreover, no mice died during the assay period. In addition, the total food obtained by the vehicle (VEH) and GTM-1-treated groups were not obviously different in two months (Fig. 5B).


Induction of autophagy by a novel small molecule improves aβ pathology and ameliorates cognitive deficits.

Chu C, Zhang X, Ma W, Li L, Wang W, Shang L, Fu P - PLoS ONE (2013)

GTM-1 rescues Aβ and Tau pathology in AD mice.A–B, GTM-1 (6 mg/kg/day) or vehicle (VEH) was administered to five-month-old 3XTg-AD mice daily for 8 weeks. The average body weight (A) and total food consumed for 8 weeks (B) was recorded. C–D, F–G, 5-month-old 3XTg-AD mice (C, D) or 15-month-old 3XTg-AD mice (F, G) were treated with GTM-1 (3 mg/kg/day) daily for 8 weeks. The insoluble and soluble Aβ42 (C, D) levels were measured using a sandwich ELISA. E, Brain proteins were obtained from 8 different 3xTg-AD mice treated with GTM-1 and 8 different 3xTg-AD mice treated with vehicle after 8 weeks of treatment. The endogenous expression of APP, C99 and C83 were assessed using western blotting analyses. CT (control treatment) mice fed with a normal (vehicle) diet. Stars indicate significant differences between the model group and control or treatment groups for that time point. *P<0.05, **P<0.01. F, Five-month-old 3XTg-AD mice were treated with GTM-1 (6 mg/kg/day) or vehicle (PC, positive control) for 2 months. The brain sample from non-Tg mice with the same generic background was used as a negative control (NC). Soluble fractions extracted from brain samples were applied onto Hybond C-extra membrane. Next, the bound oligomeric Aβ and mono-Aβ on the membranes were detected using mono-Aβ specific antibodies, and oligomer-specific antibodies, respectively. Commercial soluble Aβ monomers and oligomeric Aβs produced from the monomer were spotted as indicated and used as another control. G, Densitometric analysis of the immune dot-blot experiments was performed using a high-resolution scanner, and the average intensity of each group was normalized using the average PC result. H, Five-month-old 3XTg-AD mice were treated as previously. Representative sections obtained from the brains of mice treated with GTM-1 and vehicle were immunostained using an Aβ-specific antibody.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3672196&req=5

pone-0065367-g005: GTM-1 rescues Aβ and Tau pathology in AD mice.A–B, GTM-1 (6 mg/kg/day) or vehicle (VEH) was administered to five-month-old 3XTg-AD mice daily for 8 weeks. The average body weight (A) and total food consumed for 8 weeks (B) was recorded. C–D, F–G, 5-month-old 3XTg-AD mice (C, D) or 15-month-old 3XTg-AD mice (F, G) were treated with GTM-1 (3 mg/kg/day) daily for 8 weeks. The insoluble and soluble Aβ42 (C, D) levels were measured using a sandwich ELISA. E, Brain proteins were obtained from 8 different 3xTg-AD mice treated with GTM-1 and 8 different 3xTg-AD mice treated with vehicle after 8 weeks of treatment. The endogenous expression of APP, C99 and C83 were assessed using western blotting analyses. CT (control treatment) mice fed with a normal (vehicle) diet. Stars indicate significant differences between the model group and control or treatment groups for that time point. *P<0.05, **P<0.01. F, Five-month-old 3XTg-AD mice were treated with GTM-1 (6 mg/kg/day) or vehicle (PC, positive control) for 2 months. The brain sample from non-Tg mice with the same generic background was used as a negative control (NC). Soluble fractions extracted from brain samples were applied onto Hybond C-extra membrane. Next, the bound oligomeric Aβ and mono-Aβ on the membranes were detected using mono-Aβ specific antibodies, and oligomer-specific antibodies, respectively. Commercial soluble Aβ monomers and oligomeric Aβs produced from the monomer were spotted as indicated and used as another control. G, Densitometric analysis of the immune dot-blot experiments was performed using a high-resolution scanner, and the average intensity of each group was normalized using the average PC result. H, Five-month-old 3XTg-AD mice were treated as previously. Representative sections obtained from the brains of mice treated with GTM-1 and vehicle were immunostained using an Aβ-specific antibody.
Mentions: Cellular experiments in SH-SY5Y and MC65 cells demonstrated that GTM-1 had no toxic effect on neurons (Fig. 3C, 3D). To further evaluate the toxicity of GTM-1, the effects of GTM-1 on animal body weight were measured in WT mice. The body weights of the mice were measured at different time points during the 8-week treatment period, and the results are shown as weekly averages for groups of vehicle (VEH)- and GTM-1 (6 mg/Kg/day)-treated mice. As shown in Figure 5A and 5B, the body weights of VEH- and GTM-1 (6 mg/Kg/day)-treated animals remained similar during most of the treatment period. Moreover, no mice died during the assay period. In addition, the total food obtained by the vehicle (VEH) and GTM-1-treated groups were not obviously different in two months (Fig. 5B).

Bottom Line: GTM-1 modulates autophagy in an Akt-independent and mTOR-independent manner.In addition, we demonstrated that GTM-1 enhances autophagy clearance and reverses the downregulation of autophagy flux by thapsigargin and asparagine.Furthermore, administration of GTM-1 attenuated Aβ pathology and ameliorated cognitive deficits in AD mice.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, The First People's Hospital of Yangzhou, Jiang Su, PR China.

ABSTRACT
Growing evidence has demonstrated a neuroprotective role of autophagy in Alzheimer's disease (AD). Thus, autophagy has been regarded as a potential therapeutic target, attracting increasing interest in pharmaceutical autophagy modulation by small molecules. We designed a two-cycle screening strategy on the basis of imaging high-throughout screening (HTS) and cellular toxicity assay, and have identified a novel autophagy inducer known as GTM-1. We further showed that GTM-1 exhibits dual activities, such as autophagy induction and antagonism against Aβ-oligomer toxicity. GTM-1 modulates autophagy in an Akt-independent and mTOR-independent manner. In addition, we demonstrated that GTM-1 enhances autophagy clearance and reverses the downregulation of autophagy flux by thapsigargin and asparagine. Furthermore, administration of GTM-1 attenuated Aβ pathology and ameliorated cognitive deficits in AD mice.

Show MeSH
Related in: MedlinePlus