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Inhibitory effects of magnolol and honokiol on human calcitonin aggregation.

Guo C, Ma L, Zhao Y, Peng A, Cheng B, Zhou Q, Zheng L, Huang K - Sci Rep (2015)

Bottom Line: In this study, these two compounds were tested for their effects on hCT aggregation.Further immuno-dot blot and dynamic light scattering studies suggested Mag and Hon suppressed the aggregation of hCT both at the oligomerization and the fibrillation stages, while MTT-based and dye-leakage assays demonstrated that Mag and Hon effectively reduced cytotoxicity caused by hCT aggregates.Together, our study suggested a potential anti-amyloidogenic property of these two compounds and their structure related derivatives.

View Article: PubMed Central - PubMed

Affiliation: Tongji School of Pharmacy, Huazhong University of Science and Technology, Wuhan, Hubei, P. R. China, 430030.

ABSTRACT
Amyloid formation is associated with multiple amyloidosis diseases. Human calcitonin (hCT) is a typical amyloidogenic peptide, its aggregation is associated with medullary carcinoma of the thyroid (MTC), and also limits its clinical application. Magnolia officinalis is a traditional Chinese herbal medicine; its two major polyphenol components, magnolol (Mag) and honokiol (Hon), have displayed multiple functions. Polyphenols like flavonoids and their derivatives have been extensively studied as amyloid inhibitors. However, the anti-amyloidogenic property of a biphenyl backbone containing polyphenols such as Mag and Hon has not been reported. In this study, these two compounds were tested for their effects on hCT aggregation. We found that Mag and Hon both inhibited the amyloid formation of hCT, whereas Mag showed a stronger inhibitory effect; moreover, they both dose-dependently disassembled preformed hCT aggregates. Further immuno-dot blot and dynamic light scattering studies suggested Mag and Hon suppressed the aggregation of hCT both at the oligomerization and the fibrillation stages, while MTT-based and dye-leakage assays demonstrated that Mag and Hon effectively reduced cytotoxicity caused by hCT aggregates. Furthermore, isothermal titration calorimetry indicated Mag and Hon both interact with hCT. Together, our study suggested a potential anti-amyloidogenic property of these two compounds and their structure related derivatives.

No MeSH data available.


Related in: MedlinePlus

Disaggregation effects of magnolol and honokiol on hCT aggregates.(A,B) ThT fluorescence of disaggregation effects of magnolol (A) and honokiol (B). (C–F) TEM images of disaggregation effects of different compounds. (C) hCT incubated for 96 h; (D) hCT aggregates incubated with equimolar of EGCG for 48 h; (E–F) hCT aggregates incubated with 5-fold amounts of magnolol (E) and honokiol (F) for 48 h; Scale bar represents 500 nm. (G–I) Quantitative analysis of hCT concentration in the supernatant after disaggregation for 0 h (G), 24 h (H) and 48 h (I) in the presence of different compounds determined by bicinchoninic acid (BCA) assay.
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f6: Disaggregation effects of magnolol and honokiol on hCT aggregates.(A,B) ThT fluorescence of disaggregation effects of magnolol (A) and honokiol (B). (C–F) TEM images of disaggregation effects of different compounds. (C) hCT incubated for 96 h; (D) hCT aggregates incubated with equimolar of EGCG for 48 h; (E–F) hCT aggregates incubated with 5-fold amounts of magnolol (E) and honokiol (F) for 48 h; Scale bar represents 500 nm. (G–I) Quantitative analysis of hCT concentration in the supernatant after disaggregation for 0 h (G), 24 h (H) and 48 h (I) in the presence of different compounds determined by bicinchoninic acid (BCA) assay.

Mentions: The efficacy of Mag and Hon to disaggregate preformed hCT aggregates was determined by ThT fluorescence assay. hCT was pre-incubated for 48 h to form aggregates, different amounts of compounds were then added. Adding equimolar amounts of Mag and Hon showed no obvious disaggregation effect, while the presence of 3-fold amount of either compound prevented further aggregation of hCT (Fig. 6A,B). When the molar ratio of Mag and Hon was further increased to 5:1, the hCT aggregates were disassembled with ThT fluorescence intensity remarkably reduced to 53% and 55% of untreated control after 48 h of incubation, respectively (Fig. 7). The morphology of hCT aggregates after disaggregation was then observed under TEM. Addition of Mag and Hon disaggregated preformed hCT fibrils into small amorphous aggregates (Fig. 6E,F), which agrees with ThT fluorescence assay results. We then quantitated the soluble hCT concentrations in the supernatant after disaggregation by using bicinchoninic acid (BCA) assay. After 48 h of pre-incubation, the concentration of soluble hCT in the supernatant was lower than 20 μg/mL (Fig. 6G), whereas the equimolar amount of EGCG increased hCT concentration to ca. 50 μg/mL (P < 0.05; Fig. 6H,I). Equimolar amounts of Mag and Hon showed no obvious disaggregation effect, whereas at higher concentrations (3:1 and 5:1) significantly increased concentration of soluble hCT in the supernatant (more than 100 μg/mL) were observed after 48 h of incubation with two compounds (Fig. 6H,I).


Inhibitory effects of magnolol and honokiol on human calcitonin aggregation.

Guo C, Ma L, Zhao Y, Peng A, Cheng B, Zhou Q, Zheng L, Huang K - Sci Rep (2015)

Disaggregation effects of magnolol and honokiol on hCT aggregates.(A,B) ThT fluorescence of disaggregation effects of magnolol (A) and honokiol (B). (C–F) TEM images of disaggregation effects of different compounds. (C) hCT incubated for 96 h; (D) hCT aggregates incubated with equimolar of EGCG for 48 h; (E–F) hCT aggregates incubated with 5-fold amounts of magnolol (E) and honokiol (F) for 48 h; Scale bar represents 500 nm. (G–I) Quantitative analysis of hCT concentration in the supernatant after disaggregation for 0 h (G), 24 h (H) and 48 h (I) in the presence of different compounds determined by bicinchoninic acid (BCA) assay.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4555095&req=5

f6: Disaggregation effects of magnolol and honokiol on hCT aggregates.(A,B) ThT fluorescence of disaggregation effects of magnolol (A) and honokiol (B). (C–F) TEM images of disaggregation effects of different compounds. (C) hCT incubated for 96 h; (D) hCT aggregates incubated with equimolar of EGCG for 48 h; (E–F) hCT aggregates incubated with 5-fold amounts of magnolol (E) and honokiol (F) for 48 h; Scale bar represents 500 nm. (G–I) Quantitative analysis of hCT concentration in the supernatant after disaggregation for 0 h (G), 24 h (H) and 48 h (I) in the presence of different compounds determined by bicinchoninic acid (BCA) assay.
Mentions: The efficacy of Mag and Hon to disaggregate preformed hCT aggregates was determined by ThT fluorescence assay. hCT was pre-incubated for 48 h to form aggregates, different amounts of compounds were then added. Adding equimolar amounts of Mag and Hon showed no obvious disaggregation effect, while the presence of 3-fold amount of either compound prevented further aggregation of hCT (Fig. 6A,B). When the molar ratio of Mag and Hon was further increased to 5:1, the hCT aggregates were disassembled with ThT fluorescence intensity remarkably reduced to 53% and 55% of untreated control after 48 h of incubation, respectively (Fig. 7). The morphology of hCT aggregates after disaggregation was then observed under TEM. Addition of Mag and Hon disaggregated preformed hCT fibrils into small amorphous aggregates (Fig. 6E,F), which agrees with ThT fluorescence assay results. We then quantitated the soluble hCT concentrations in the supernatant after disaggregation by using bicinchoninic acid (BCA) assay. After 48 h of pre-incubation, the concentration of soluble hCT in the supernatant was lower than 20 μg/mL (Fig. 6G), whereas the equimolar amount of EGCG increased hCT concentration to ca. 50 μg/mL (P < 0.05; Fig. 6H,I). Equimolar amounts of Mag and Hon showed no obvious disaggregation effect, whereas at higher concentrations (3:1 and 5:1) significantly increased concentration of soluble hCT in the supernatant (more than 100 μg/mL) were observed after 48 h of incubation with two compounds (Fig. 6H,I).

Bottom Line: In this study, these two compounds were tested for their effects on hCT aggregation.Further immuno-dot blot and dynamic light scattering studies suggested Mag and Hon suppressed the aggregation of hCT both at the oligomerization and the fibrillation stages, while MTT-based and dye-leakage assays demonstrated that Mag and Hon effectively reduced cytotoxicity caused by hCT aggregates.Together, our study suggested a potential anti-amyloidogenic property of these two compounds and their structure related derivatives.

View Article: PubMed Central - PubMed

Affiliation: Tongji School of Pharmacy, Huazhong University of Science and Technology, Wuhan, Hubei, P. R. China, 430030.

ABSTRACT
Amyloid formation is associated with multiple amyloidosis diseases. Human calcitonin (hCT) is a typical amyloidogenic peptide, its aggregation is associated with medullary carcinoma of the thyroid (MTC), and also limits its clinical application. Magnolia officinalis is a traditional Chinese herbal medicine; its two major polyphenol components, magnolol (Mag) and honokiol (Hon), have displayed multiple functions. Polyphenols like flavonoids and their derivatives have been extensively studied as amyloid inhibitors. However, the anti-amyloidogenic property of a biphenyl backbone containing polyphenols such as Mag and Hon has not been reported. In this study, these two compounds were tested for their effects on hCT aggregation. We found that Mag and Hon both inhibited the amyloid formation of hCT, whereas Mag showed a stronger inhibitory effect; moreover, they both dose-dependently disassembled preformed hCT aggregates. Further immuno-dot blot and dynamic light scattering studies suggested Mag and Hon suppressed the aggregation of hCT both at the oligomerization and the fibrillation stages, while MTT-based and dye-leakage assays demonstrated that Mag and Hon effectively reduced cytotoxicity caused by hCT aggregates. Furthermore, isothermal titration calorimetry indicated Mag and Hon both interact with hCT. Together, our study suggested a potential anti-amyloidogenic property of these two compounds and their structure related derivatives.

No MeSH data available.


Related in: MedlinePlus