Acta Veterinaria et Zootechnica Sinica ›› 2022, Vol. 53 ›› Issue (8): 2721-2728.doi: 10.11843/j.issn.0366-6964.2022.08.029

• BASIC VETERINARY MEDICINE • Previous Articles     Next Articles

The Cytotoxicity of Amyloid Fibrils Formed by Hen Egg-White Lysozyme on SH-SY5Y Cells

BAI Yu*, WANG Wu, WANG Bi, LI Ying, FENG Zili   

  1. Shaanxi Province Key Laboratory of Bio-resources, College of Biological Science and Engineering, Shaanxi University of Technology, Hanzhong 723000, China
  • Received:2021-11-15 Online:2022-08-23 Published:2022-08-23

Abstract: The aim of this study was to investigate the cytotoxicity effect of amyloid fibrils of hen egg-white lysozyme (HEWL) on SH-SY5Y cells. The 100 μmol·L-1 HEWL protein was incubated with agitation at 57℃ in glycine solution of pH 2.0. The ultrastructure of HEWL amyloid fibrils was observed under transmission electron microscopy, the hydrophobicity was detected by ANS fluorescence, the secondary structural contents were measured and analyzed by circular dichroism. After SH-SY5Y cells were treated by the formed HEWL fibrils, the cell viability was determined by MTT assay and the apoptosis features were detected by nuclear staining. The transmission electron microscopy results showed that HEWL protein formed short and rod-shaped amyloid fibrils after 4 days of incubation. Meanwhile, compared with the native HEWL protein, the surface hydrophobicity and β-sheet structure of aggregates were both greatly increased. Furthermore, 1-3 μmol·L-1 HEWL fibrils all produced significant cytotoxicity in SH-SY5Y cells after 12, 24 and 48 h treatments(P<0.01). For different concentrations of 1, 2 and 3 μmol·L-1 HEWL fibrils, the cell viability were 75.16%±15.51%, 67.54%±12.13% and 67.89%±10.26% for 12 h treatment,respectively; 75.78±13.01%, 58.41%±5.55% and 61.90%±8.94% for 24 h treatment,respectively; 71.59%±14.75%, 55.65%±5.78% and 46.45%±6.23% for 48 h treatment,and the decreased cell viability displayed time-dependent and concentration-dependent manner. Nuclear staining results further confirmed the apoptosis features. These results suggest that HEWL protein could form into toxic amyloid fibrils under certain physicochemical conditions, which could provide basis for understanding the mechanisms of amyloid fibrils forming of prion protein and other amyloid proteins.

Key words: amyloid fibrils, hen egg-white lysozyme, β-sheet, SH-SY5Y cells

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