HEWL interacts with dissipated oleic acid micelles, and decreases oleic acid cytotoxicity.

Qin Huang,Dan Sun,Muhammad Zubair Hussain,Ludmilla A Morozova-Roche,Ce Zhang,Yonggang Liu,Eugene A Permyakov

doi:10.1371/journal.pone.0212648

Qin Huang, Dan Sun + Show 5 more

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https://doi.org/10.1371/journal.pone.0212648

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Abstract

Senile plaques are well-known hallmarks of Alzheimer’s Diseases (AD). However, drugs targeting tangles of the protein tau and plaques of β-amyloid have no significant effect on disease progression, and the studies on the underlying mechanism of AD remain in high demand. Growing evidence supports the protective role of senile plaques in local inflammation driven by S100A9. We herein demonstrate that oleic acid (OA) micelles interact with hen egg white lysozyme (HEWL) and promote its amyloid formation. Consequently, SH-SY5Y cell line and mouse neural stem cells are rescued from OA toxicity by co-aggregation of OA and HEWL. Using atomic force microscopy in combination with fluorescence microscopy, we revealed that HEWL forms round-shaped aggregates in the presence of OA micelles instead of protofibrils of HEWL alone. These HEWL amyloids act as a sink for toxic OA micelles and their co-aggregate form large clumps, suggesting a protective function in amyloid and OA cytotoxicity.

Highlights

hen egg white lysozyme (HEWL) interacts with dissipated oleic acid micelles, and decreases oleic acid cytotoxicity were subjected to continuous shaking at 800 rpm and 57 ̊C
HEWL amyloid formation with or without oleic acid (OA) micelles was firstly examined by Atomic Force Microscopy (AFM) (Fig 1A)
HEWL interacts with dissipated oleic acid micelles, and decreases oleic acid cytotoxicity amyloid formation was monitored by far UV circular dichroism (CD) (Fig 1C)

Summary

Methods

HEWL (Aldrich-Sigma) was used without any further purification. All HEWL samples were dissolved in 20 mM glycine buffer, and adjusted to pH 2.3 before mixing with OA. The protein concentration was determined by weight and NanoDrop measurements. Mixtures of HEWL, OA and dimethyl sulfoxide (DMSO) are named after their contents: P (1.4 mM HEWL); PD (1.4 mM HEWL and 5.6 M DMSO); POA10 (1.4 mM HEWL and 14 mM OA); POA100 (1.4 mM HEWL and 140 mM OA). In order to produce and maintain OA micelles, all samples. HEWL interacts with dissipated oleic acid micelles, and decreases oleic acid cytotoxicity were subjected to continuous shaking at 800 rpm and 57 ̊C. All chemicals were purchased from Sigma unless mentioned differently

Results

Discussion

Conclusion