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Chaudhary S, Ashok A, Wise AS, Rana NA, Kritikos AE, Lindner E, Singh N. β-Cleavage of the prion protein in the human eye: Implications for the spread of infectious prions and human ocular disorders. Exp Eye Res 2021; 212:108787. [PMID: 34624335 DOI: 10.1016/j.exer.2021.108787] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 09/29/2021] [Accepted: 10/04/2021] [Indexed: 11/26/2022]
Abstract
Recently, we reported β-cleavage of the prion protein (PrPC) in human ocular tissues. Here, we explored whether this is unique to the human eye, and its functional implications. A comparison of the cleavage pattern of PrPC in human ocular tissues with common nocturnal and diurnal animals revealed mainly β-cleavage in humans, and mostly full-length PrPC in animal retinas. Soluble FL PrPC and N-terminal fragment (N2) released from β-cleavage was observed in the aqueous and vitreous humor (AH & VH). Expression of human PrPC in ARPE-19 cells, a human retinal pigmented epithelial cell line, also showed β-cleaved PrPC. Surprisingly, β-cleavage was not altered by a variety of insults, including oxidative stress, suggesting a unique role of this cleavage in the human eye. It is likely that β-cleaved C- or N-terminal fragments of PrPC protect from various insults unique to the human eye. On the contrary, β-cleaved C-terminus of PrPC is susceptible to conversion to the pathological PrP-scrapie form, and includes the binding sites for β1-integrin and amyloid-β, molecules implicated in several ocular disorders. Considering the species and tissue-specific cleavage of PrPC, our data suggest re-evaluation of prion infectivity and other ocular disorders of the human eye conducted in mouse models.
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Affiliation(s)
- Suman Chaudhary
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Ajay Ashok
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Aaron S Wise
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Neil A Rana
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Alexander E Kritikos
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Ewald Lindner
- Department of Ophthalmology, Medical University of Graz, Auenbruggerplatz 4, 8036, Graz, Austria
| | - Neena Singh
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA.
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