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Gelsolin Amyloidogenesis Is Effectively Modulated by Curcumin and Emetine Conjugated PLGA Nanoparticles.

Srivastava A, Arya P, Goel S, Kundu B, Mishra P, Fnu A - PLoS ONE (2015)

Bottom Line: These two types of aggregates differed in their morphologies, surface hydrophobicity and secondary structural signatures, confirming that they followed distinct pathways.In spite of differences, both these aggregates displayed reduced toxicity against SH-SY5Y human neuroblastoma cells as compared to control gelsolin amyloids.We conclude that the cytotoxicity of gelsolin amyloids can be reduced by either stalling or accelerating its fibrillation process.

View Article: PubMed Central - PubMed

Affiliation: Kusuma School of Biological Sciences, IIT Delhi, New Delhi, India.

ABSTRACT
Small molecule based therapeutic intervention of amyloids has been limited by their low solubility and poor pharmacokinetic characteristics. We report here, the use of water soluble poly lactic-co-glycolic acid (PLGA)-encapsulated curcumin and emetine nanoparticles (Cm-NPs and Em-NPs, respectively), as potential modulators of gelsolin amyloidogenesis. Using the amyloid-specific dye Thioflavin T (ThT) as an indicator along with electron microscopic imaging we show that the presence of Cm-NPs augmented amyloid formation in gelsolin by skipping the pre-fibrillar assemblies, while Em-NPs induced non-fibrillar aggregates. These two types of aggregates differed in their morphologies, surface hydrophobicity and secondary structural signatures, confirming that they followed distinct pathways. In spite of differences, both these aggregates displayed reduced toxicity against SH-SY5Y human neuroblastoma cells as compared to control gelsolin amyloids. We conclude that the cytotoxicity of gelsolin amyloids can be reduced by either stalling or accelerating its fibrillation process. In addition, Cm-NPs increased the fibrillar bulk while Em-NPs defibrillated the pre-formed gelsolin amyloids. Moreover, amyloid modulation happened at a much lower concentration and at a faster rate by the PLGA encapsulated compounds as compared to their free forms. Thus, besides improving pharmacokinetic and biocompatible properties of curcumin and emetine, PLGA conjugation elevates the therapeutic potential of both small molecules against amyloid fibrillation and toxicity.

No MeSH data available.


Related in: MedlinePlus

Kinetics and morphology of fAGel aggregation.(A) Amyloid formation kinetics of fAGel alone monitored by ThT fluorescence showing sigmoidal trend with 18 h lag phase. (B) TEM image of amyloids formed after 24 h incubation. Scale bar 500 nm. (C) AFM image taken after 60 h showing fibrillar aggregates of fAGel. Scale bar 200 nm. The fAGel concentration was 2 mg/ml.
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pone.0127011.g004: Kinetics and morphology of fAGel aggregation.(A) Amyloid formation kinetics of fAGel alone monitored by ThT fluorescence showing sigmoidal trend with 18 h lag phase. (B) TEM image of amyloids formed after 24 h incubation. Scale bar 500 nm. (C) AFM image taken after 60 h showing fibrillar aggregates of fAGel. Scale bar 200 nm. The fAGel concentration was 2 mg/ml.

Mentions: The aggregation kinetics of fAGel at pH 4.0, 37°C was followed by monitoring the changes in Thioflavin T (ThT) fluorescence, a widely used fluorescent dye used for characterizing amyloid kinetics [40]. Evidently, the fAGel aggregation showed a time-dependent increase (k = 7.9 h-1) in the ThT fluorescence, followed a sigmoidal trace before saturating around 60 h (Fig 4A). A distinct lag phase (~18 h) was observed, suggesting that the polypeptide undergoes nucleation-dependent polymerization under these conditions, a phenomenon generally reported for other amyloidogenic polypeptides [41–43]. The TEM images taken after 24 h showed the presence of protofilaments and early fibrillar aggregates (Fig 4B). The corresponding AFM images taken after 60 h incubation showed the presence of mature fibrils of 8.6 nm average width and 5.2 nm average height having smooth morphologies (Fig 4C, S2 Fig).


Gelsolin Amyloidogenesis Is Effectively Modulated by Curcumin and Emetine Conjugated PLGA Nanoparticles.

Srivastava A, Arya P, Goel S, Kundu B, Mishra P, Fnu A - PLoS ONE (2015)

Kinetics and morphology of fAGel aggregation.(A) Amyloid formation kinetics of fAGel alone monitored by ThT fluorescence showing sigmoidal trend with 18 h lag phase. (B) TEM image of amyloids formed after 24 h incubation. Scale bar 500 nm. (C) AFM image taken after 60 h showing fibrillar aggregates of fAGel. Scale bar 200 nm. The fAGel concentration was 2 mg/ml.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4440822&req=5

pone.0127011.g004: Kinetics and morphology of fAGel aggregation.(A) Amyloid formation kinetics of fAGel alone monitored by ThT fluorescence showing sigmoidal trend with 18 h lag phase. (B) TEM image of amyloids formed after 24 h incubation. Scale bar 500 nm. (C) AFM image taken after 60 h showing fibrillar aggregates of fAGel. Scale bar 200 nm. The fAGel concentration was 2 mg/ml.
Mentions: The aggregation kinetics of fAGel at pH 4.0, 37°C was followed by monitoring the changes in Thioflavin T (ThT) fluorescence, a widely used fluorescent dye used for characterizing amyloid kinetics [40]. Evidently, the fAGel aggregation showed a time-dependent increase (k = 7.9 h-1) in the ThT fluorescence, followed a sigmoidal trace before saturating around 60 h (Fig 4A). A distinct lag phase (~18 h) was observed, suggesting that the polypeptide undergoes nucleation-dependent polymerization under these conditions, a phenomenon generally reported for other amyloidogenic polypeptides [41–43]. The TEM images taken after 24 h showed the presence of protofilaments and early fibrillar aggregates (Fig 4B). The corresponding AFM images taken after 60 h incubation showed the presence of mature fibrils of 8.6 nm average width and 5.2 nm average height having smooth morphologies (Fig 4C, S2 Fig).

Bottom Line: These two types of aggregates differed in their morphologies, surface hydrophobicity and secondary structural signatures, confirming that they followed distinct pathways.In spite of differences, both these aggregates displayed reduced toxicity against SH-SY5Y human neuroblastoma cells as compared to control gelsolin amyloids.We conclude that the cytotoxicity of gelsolin amyloids can be reduced by either stalling or accelerating its fibrillation process.

View Article: PubMed Central - PubMed

Affiliation: Kusuma School of Biological Sciences, IIT Delhi, New Delhi, India.

ABSTRACT
Small molecule based therapeutic intervention of amyloids has been limited by their low solubility and poor pharmacokinetic characteristics. We report here, the use of water soluble poly lactic-co-glycolic acid (PLGA)-encapsulated curcumin and emetine nanoparticles (Cm-NPs and Em-NPs, respectively), as potential modulators of gelsolin amyloidogenesis. Using the amyloid-specific dye Thioflavin T (ThT) as an indicator along with electron microscopic imaging we show that the presence of Cm-NPs augmented amyloid formation in gelsolin by skipping the pre-fibrillar assemblies, while Em-NPs induced non-fibrillar aggregates. These two types of aggregates differed in their morphologies, surface hydrophobicity and secondary structural signatures, confirming that they followed distinct pathways. In spite of differences, both these aggregates displayed reduced toxicity against SH-SY5Y human neuroblastoma cells as compared to control gelsolin amyloids. We conclude that the cytotoxicity of gelsolin amyloids can be reduced by either stalling or accelerating its fibrillation process. In addition, Cm-NPs increased the fibrillar bulk while Em-NPs defibrillated the pre-formed gelsolin amyloids. Moreover, amyloid modulation happened at a much lower concentration and at a faster rate by the PLGA encapsulated compounds as compared to their free forms. Thus, besides improving pharmacokinetic and biocompatible properties of curcumin and emetine, PLGA conjugation elevates the therapeutic potential of both small molecules against amyloid fibrillation and toxicity.

No MeSH data available.


Related in: MedlinePlus