G. Panza, C. Dumpitak, D. Willbold, E. Birkmann

Protein glycation was viewed originally as a post-translational modification that accumulated mostly on extracellular proteins. Specifically, advanced glycation endproducts (AGEs) were thought to be formed slowly throughout life and the concentrations of AGEs found represent a life-long accumulation of the glycation adduct (1).

Prions are the agents of transmissible spongiform encephalopathies like Creutzfeldt-Jakob disease (CJD) or Scrapie. They are mainly composed of aggregated and misfolded prion protein (PrP). Although the prion theory was proven by in vitro generation of synthetic prions from recombinant PrP only (2, 3), the molecular details of prion formation are not yet fully understood, especially since synthetic prions led only to small titers of infectivity. Therefore it is essential to understand PrP misfolding and aggregation also in the context of PrP-modifications in naturally occurring prions. Such PrP modifications could arise from the Maillard reaction in vivo - a well known complex reaction cascade between reducing sugars and reactive amino groups of proteins leading to several modifications in proteins like adducts or crosslinks, called AGEs and capable of facilitating protein aggregation and fibrillization [3]

We addressed the question whether formation of AGEs - could participate in prion pathogenesis. In a first step we analysed several PrP-preparations (infectious and non-infectious) via immunochemical detection utilising specific antibodies against common AGEs and obtained immunopositive reactions in all examined preparations. Furthermore we investigated the influence of the Maillard reaction to PrP aggregation and fibrillization in vitro. Here we demonstrated that AGEs-modification of PrP in vitro affects the ability of fibril formation. Our results are of particular interest in prion neurotoxicity and pathogenesis. As in Alzheimer's or Parkinson's disease it seems possible that the Maillard reaction could play a role in prion diseases.

(1) Thornalley PJ, (2008) Drug Metabol Drug Interact.; 23(1-2): 125-150.

(2) Legname G, et al. (2004). Science 305: 673-676.

(3) Legname G, et al. (2005). Proc. Natl. Acad. Sci. USA 102: 2168-2173

Keywords (Optional): 
advanced glycation endproducts
protein aggregation
protein glycation