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The Components of Flemingia macrophylla Attenuate Amyloid β-Protein Accumulation by Regulating Amyloid β-Protein Metabolic Pathway.

Lin YL, Tsay HJ, Liao YF, Wu MF, Wang CN, Shiao YJ - Evid Based Complement Alternat Med (2012)

Bottom Line: Therefore, the effects of F. macrophylla on Aβ production and degradation were studied.The effect of F. macrophylla on Aβ metabolism was detected using the cultured mouse neuroblastoma cells N2a transfected with human Swedish mutant APP (swAPP-N2a cells).The effects on Aβ degradation were evaluated on a cell-free system.

View Article: PubMed Central - PubMed

Affiliation: Division of Medicinal Chemistry, National Research Institute of Chinese Medicine, Taipei 112, Taiwan.

ABSTRACT
Flemingia macrophylla (Leguminosae) is a popular traditional remedy used in Taiwan as anti-inflammatory, promoting blood circulation and antidiabetes agent. Recent study also suggested its neuroprotective activity against Alzheimer's disease. Therefore, the effects of F. macrophylla on Aβ production and degradation were studied. The effect of F. macrophylla on Aβ metabolism was detected using the cultured mouse neuroblastoma cells N2a transfected with human Swedish mutant APP (swAPP-N2a cells). The effects on Aβ degradation were evaluated on a cell-free system. An ELISA assay was applied to detect the level of Aβ1-40 and Aβ1-42. Western blots assay was employed to measure the levels of soluble amyloid precursor protein and insulin degrading enzyme (IDE). Three fractions of F. macrophylla modified Aβ accumulation by both inhibiting β-secretase and activating IDE. Three flavonoids modified Aβ accumulation by activating IDE. The activated IDE pool by the flavonoids was distinctly regulated by bacitracin (an IDE inhibitor). Furthermore, flavonoid 94-18-13 also modulates Aβ accumulation by enhancing IDE expression. In conclusion, the components of F. macrophylla possess the potential for developing new therapeutic drugs for Alzheimer's disease.

No MeSH data available.


Related in: MedlinePlus

The effect of insulin and bacitracin on the level of extracellular and intracellular Aβ1-40. APP-transfected N2a cells were treated with indicated concentrations of insulin and bacitracin for 20 h. The level of extracellular (a) and intracellular (b) Aβ1-40 was determined by ELISA. Results are means ± SD from three independent experiments. Significant differences between control and treated cells are indicated by *P < 0.05, ***P < 0.001.
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fig2: The effect of insulin and bacitracin on the level of extracellular and intracellular Aβ1-40. APP-transfected N2a cells were treated with indicated concentrations of insulin and bacitracin for 20 h. The level of extracellular (a) and intracellular (b) Aβ1-40 was determined by ELISA. Results are means ± SD from three independent experiments. Significant differences between control and treated cells are indicated by *P < 0.05, ***P < 0.001.

Mentions: To determine the importance of IDE activity on the levels of both extracellular and intracellular Aβ1-40 in swAPP-N2a cell culture, various concentrations of insulin (the substrate of IDE) and/or 2 nM bacitracin (a competitive inhibitor of IDE) were subjected into swAPP-N2a cell culture, and the Aβ1-40 accumulation was assayed. The results showed that insulin promotes Aβ1-40 accumulation in a concentration-dependent manner. Extracellular Aβ1-40 was hardly detected (i.e., 0.88 ± 1.07 ng/mL) in the culture medium without containing insulin. Insulin at 10, 100, 1000, and 4200 nM increased the level of extracellular Aβ1-40 to 3.70 ± 2.18 ng/mL, 14.78 ± 2.17 ng/mL, 23.38 ± 1.83 ng/mL, and 26.02 ± 1.45 ng/mL, respectively (Figure 2(a)). The results suggested that about 26 ng/mL of extracellular Aβ1-40 in the cultured medium regulated by insulin sensitive peptidase(s), including IDE. Therefore, bacitracin was employed to verify the IDE-sensitive pool of extracellular Aβ1-40 in the cultured medium. The results showed that 2 nM bacitracin increased the level of extracellular Aβ1-40 to 10.66 ± 1.32 ng/mL (Figure 2(a)), and higher concentration of bacitracin did not significantly enhance this effect, suggesting that about 11 ng/mL of extracellular Aβ1-40 in the cultured medium was regulated by IDE.


The Components of Flemingia macrophylla Attenuate Amyloid β-Protein Accumulation by Regulating Amyloid β-Protein Metabolic Pathway.

Lin YL, Tsay HJ, Liao YF, Wu MF, Wang CN, Shiao YJ - Evid Based Complement Alternat Med (2012)

The effect of insulin and bacitracin on the level of extracellular and intracellular Aβ1-40. APP-transfected N2a cells were treated with indicated concentrations of insulin and bacitracin for 20 h. The level of extracellular (a) and intracellular (b) Aβ1-40 was determined by ELISA. Results are means ± SD from three independent experiments. Significant differences between control and treated cells are indicated by *P < 0.05, ***P < 0.001.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3376484&req=5

fig2: The effect of insulin and bacitracin on the level of extracellular and intracellular Aβ1-40. APP-transfected N2a cells were treated with indicated concentrations of insulin and bacitracin for 20 h. The level of extracellular (a) and intracellular (b) Aβ1-40 was determined by ELISA. Results are means ± SD from three independent experiments. Significant differences between control and treated cells are indicated by *P < 0.05, ***P < 0.001.
Mentions: To determine the importance of IDE activity on the levels of both extracellular and intracellular Aβ1-40 in swAPP-N2a cell culture, various concentrations of insulin (the substrate of IDE) and/or 2 nM bacitracin (a competitive inhibitor of IDE) were subjected into swAPP-N2a cell culture, and the Aβ1-40 accumulation was assayed. The results showed that insulin promotes Aβ1-40 accumulation in a concentration-dependent manner. Extracellular Aβ1-40 was hardly detected (i.e., 0.88 ± 1.07 ng/mL) in the culture medium without containing insulin. Insulin at 10, 100, 1000, and 4200 nM increased the level of extracellular Aβ1-40 to 3.70 ± 2.18 ng/mL, 14.78 ± 2.17 ng/mL, 23.38 ± 1.83 ng/mL, and 26.02 ± 1.45 ng/mL, respectively (Figure 2(a)). The results suggested that about 26 ng/mL of extracellular Aβ1-40 in the cultured medium regulated by insulin sensitive peptidase(s), including IDE. Therefore, bacitracin was employed to verify the IDE-sensitive pool of extracellular Aβ1-40 in the cultured medium. The results showed that 2 nM bacitracin increased the level of extracellular Aβ1-40 to 10.66 ± 1.32 ng/mL (Figure 2(a)), and higher concentration of bacitracin did not significantly enhance this effect, suggesting that about 11 ng/mL of extracellular Aβ1-40 in the cultured medium was regulated by IDE.

Bottom Line: Therefore, the effects of F. macrophylla on Aβ production and degradation were studied.The effect of F. macrophylla on Aβ metabolism was detected using the cultured mouse neuroblastoma cells N2a transfected with human Swedish mutant APP (swAPP-N2a cells).The effects on Aβ degradation were evaluated on a cell-free system.

View Article: PubMed Central - PubMed

Affiliation: Division of Medicinal Chemistry, National Research Institute of Chinese Medicine, Taipei 112, Taiwan.

ABSTRACT
Flemingia macrophylla (Leguminosae) is a popular traditional remedy used in Taiwan as anti-inflammatory, promoting blood circulation and antidiabetes agent. Recent study also suggested its neuroprotective activity against Alzheimer's disease. Therefore, the effects of F. macrophylla on Aβ production and degradation were studied. The effect of F. macrophylla on Aβ metabolism was detected using the cultured mouse neuroblastoma cells N2a transfected with human Swedish mutant APP (swAPP-N2a cells). The effects on Aβ degradation were evaluated on a cell-free system. An ELISA assay was applied to detect the level of Aβ1-40 and Aβ1-42. Western blots assay was employed to measure the levels of soluble amyloid precursor protein and insulin degrading enzyme (IDE). Three fractions of F. macrophylla modified Aβ accumulation by both inhibiting β-secretase and activating IDE. Three flavonoids modified Aβ accumulation by activating IDE. The activated IDE pool by the flavonoids was distinctly regulated by bacitracin (an IDE inhibitor). Furthermore, flavonoid 94-18-13 also modulates Aβ accumulation by enhancing IDE expression. In conclusion, the components of F. macrophylla possess the potential for developing new therapeutic drugs for Alzheimer's disease.

No MeSH data available.


Related in: MedlinePlus