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αB-crystallin inhibits the cell toxicity associated with amyloid fibril formation by kappa-casein and the amyloid-β peptide

Journal Article


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Abstract


  • Amyloid fibril formation is associated with diseases such as Alzheimer’s, Parkinson’s, and prion diseases. Inhibition of amyloid fibril formation by molecular chaperone proteins, such as the small heat-shock protein αB-crystallin, may play a protective role in preventing the toxicity associated with this form of protein misfolding. Reduced and carboxymethylated κ-casein (RCMκ-CN), a protein derived from milk, readily and reproducibly forms fibrils at physiological temperature and pH. We investigated the toxicity of fibril formation by RCMκ-CN using neuronal model PC12 cells and determined whether the inhibition of fibril formation altered its cell toxicity. To resolve ambiguities in the literature, we also investigated whether fibril formation by amyloid-β1–40 (Aβ1–40), the peptide associated with Alzheimer’s disease, was inhibited by αB-crystallin and if this affected the toxicity of Aβ. To this end, either RCMκ-CN or Aβ1–40 was incubated at neutral pH to induce fibril formation before treating PC12 cells and assessing cell viability. Incubated (fibrillar) RCMκ-CN was more toxic to PC12 cells than native RCMκ-CN with the highest level of toxicity being associated with mature fibrils and protofibrils. Furthermore, the toxicity of RCMκ-CN was attenuated when its fibril formation was inhibited, either through the chaperone action of αB-crystallin or when it interacted with its natural binding partners in milk, αS- and β-casein. Likewise, incubating Aβ1–40 with αB-crystallin inhibited both Aβ1–40 fibril formation and the associated cell toxicity. Importantly, by inhibiting fibril formation, αB-crystallin prevents the cell toxicity associated with protein misfolding.

Authors


  •   Dehle, Francis C. (external author)
  •   Ecroyd, Heath
  •   Musgrave, Ian F. (external author)
  •   Carver, John A. (external author)

Publication Date


  • 2010

Citation


  • Dehle, F. C., Ecroyd, H., Musgrave, I. F. & Carver, J. A. (2010). αB-crystallin inhibits the cell toxicity associated with amyloid fibril formation by kappa-casein and the amyloid-β peptide. Cell Stress and Chaperones, 15 (6), 1013-1026.

Scopus Eid


  • 2-s2.0-78149466716

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=1992&context=scipapers

Ro Metadata Url


  • http://ro.uow.edu.au/scipapers/953

Has Global Citation Frequency


Number Of Pages


  • 13

Start Page


  • 1013

End Page


  • 1026

Volume


  • 15

Issue


  • 6

Abstract


  • Amyloid fibril formation is associated with diseases such as Alzheimer’s, Parkinson’s, and prion diseases. Inhibition of amyloid fibril formation by molecular chaperone proteins, such as the small heat-shock protein αB-crystallin, may play a protective role in preventing the toxicity associated with this form of protein misfolding. Reduced and carboxymethylated κ-casein (RCMκ-CN), a protein derived from milk, readily and reproducibly forms fibrils at physiological temperature and pH. We investigated the toxicity of fibril formation by RCMκ-CN using neuronal model PC12 cells and determined whether the inhibition of fibril formation altered its cell toxicity. To resolve ambiguities in the literature, we also investigated whether fibril formation by amyloid-β1–40 (Aβ1–40), the peptide associated with Alzheimer’s disease, was inhibited by αB-crystallin and if this affected the toxicity of Aβ. To this end, either RCMκ-CN or Aβ1–40 was incubated at neutral pH to induce fibril formation before treating PC12 cells and assessing cell viability. Incubated (fibrillar) RCMκ-CN was more toxic to PC12 cells than native RCMκ-CN with the highest level of toxicity being associated with mature fibrils and protofibrils. Furthermore, the toxicity of RCMκ-CN was attenuated when its fibril formation was inhibited, either through the chaperone action of αB-crystallin or when it interacted with its natural binding partners in milk, αS- and β-casein. Likewise, incubating Aβ1–40 with αB-crystallin inhibited both Aβ1–40 fibril formation and the associated cell toxicity. Importantly, by inhibiting fibril formation, αB-crystallin prevents the cell toxicity associated with protein misfolding.

Authors


  •   Dehle, Francis C. (external author)
  •   Ecroyd, Heath
  •   Musgrave, Ian F. (external author)
  •   Carver, John A. (external author)

Publication Date


  • 2010

Citation


  • Dehle, F. C., Ecroyd, H., Musgrave, I. F. & Carver, J. A. (2010). αB-crystallin inhibits the cell toxicity associated with amyloid fibril formation by kappa-casein and the amyloid-β peptide. Cell Stress and Chaperones, 15 (6), 1013-1026.

Scopus Eid


  • 2-s2.0-78149466716

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=1992&context=scipapers

Ro Metadata Url


  • http://ro.uow.edu.au/scipapers/953

Has Global Citation Frequency


Number Of Pages


  • 13

Start Page


  • 1013

End Page


  • 1026

Volume


  • 15

Issue


  • 6