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Vanni I, Iacobone F, D’Agostino C, Giovannelli M, Pirisinu L, Altmeppen HC, Castilla J, Torres JM, Agrimi U, Nonno R. An optimized Western blot assay provides a comprehensive assessment of the physiological endoproteolytic processing of the prion protein. J Biol Chem 2022; 299:102823. [PMID: 36565989 PMCID: PMC9867980 DOI: 10.1016/j.jbc.2022.102823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 12/06/2022] [Accepted: 12/10/2022] [Indexed: 12/24/2022] Open
Abstract
The prion protein (PrPC) is subjected to several conserved endoproteolytic events producing bioactive fragments that are of increasing interest for their physiological functions and their implication in the pathogenesis of prion diseases and other neurodegenerative diseases. However, systematic and comprehensive investigations on the full spectrum of PrPC proteoforms have been hampered by the lack of methods able to identify all PrPC-derived proteoforms. Building on previous knowledge of PrPC endoproteolytic processing, we thus developed an optimized Western blot assay able to obtain the maximum information about PrPC constitutive processing and the relative abundance of PrPC proteoforms in a complex biological sample. This approach led to the concurrent identification of the whole spectrum of known endoproteolytic-derived PrPC proteoforms in brain homogenates, including C-terminal, N-terminal and, most importantly, shed PrPC-derived fragments. Endoproteolytic processing of PrPC was remarkably similar in the brain of widely used wild type and transgenic rodent models, with α-cleavage-derived C1 representing the most abundant proteoform and ADAM10-mediated shedding being an unexpectedly prominent proteolytic event. Interestingly, the relative amount of shed PrPC was higher in WT mice than in most other models. Our results indicate that constitutive endoproteolytic processing of PrPC is not affected by PrPC overexpression or host factors other than PrPC but can be impacted by PrPC primary structure. Finally, this method represents a crucial step in gaining insight into pathophysiological roles, biomarker suitability, and therapeutic potential of shed PrPC and for a comprehensive appraisal of PrPC proteoforms in therapies, drug screening, or in the progression of neurodegenerative diseases.
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Affiliation(s)
- Ilaria Vanni
- Department of Food Safety, Nutrition and Veterinary Public Health, Istituto Superiore di Sanità, Rome, Italy.
| | - Floriana Iacobone
- Department of Food Safety, Nutrition and Veterinary Public Health, Istituto Superiore di Sanità, Rome, Italy
| | - Claudia D’Agostino
- Department of Food Safety, Nutrition and Veterinary Public Health, Istituto Superiore di Sanità, Rome, Italy
| | - Matteo Giovannelli
- Department of Food Safety, Nutrition and Veterinary Public Health, Istituto Superiore di Sanità, Rome, Italy
| | - Laura Pirisinu
- Department of Food Safety, Nutrition and Veterinary Public Health, Istituto Superiore di Sanità, Rome, Italy
| | | | - Joaquin Castilla
- Basque Research and Technology Alliance (BRTA) - CIC BioGUNE & IKERBasque, Bizkaia, Spain,Centro de Investigación Biomédica en Red de Enfermedades infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain
| | - Juan Maria Torres
- Centro de Investigación en Sanidad Animal (CISA-INIA-CSIC), Valdeolmos, Madrid, Spain
| | - Umberto Agrimi
- Department of Food Safety, Nutrition and Veterinary Public Health, Istituto Superiore di Sanità, Rome, Italy
| | - Romolo Nonno
- Department of Food Safety, Nutrition and Veterinary Public Health, Istituto Superiore di Sanità, Rome, Italy
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Puig B, Yang D, Brenna S, Altmeppen HC, Magnus T. Show Me Your Friends and I Tell You Who You Are: The Many Facets of Prion Protein in Stroke. Cells 2020; 9:E1609. [PMID: 32630841 PMCID: PMC7407975 DOI: 10.3390/cells9071609] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 06/24/2020] [Accepted: 06/27/2020] [Indexed: 12/12/2022] Open
Abstract
Ischemic stroke belongs to the leading causes of mortality and disability worldwide. Although treatments for the acute phase of stroke are available, not all patients are eligible. There is a need to search for therapeutic options to promote neurological recovery after stroke. The cellular prion protein (PrPC) has been consistently linked to a neuroprotective role after ischemic damage: it is upregulated in the penumbra area following stroke in humans, and animal models of stroke have shown that lack of PrPC aggravates the ischemic damage and lessens the functional outcome. Mechanistically, these effects can be linked to numerous functions attributed to PrPC: (1) as a signaling partner of the PI3K/Akt and MAPK pathways, (2) as a regulator of glutamate receptors, and (3) promoting stem cell homing mechanisms, leading to angio- and neurogenesis. PrPC can be cleaved at different sites and the proteolytic fragments can account for the manifold functions. Moreover, PrPC is present on extracellular vesicles (EVs), released membrane particles originating from all types of cells that have drawn attention as potential therapeutic tools in stroke and many other diseases. Thus, identification of the many mechanisms underlying PrPC-induced neuroprotection will not only provide further understanding of the physiological functions of PrPC but also new ideas for possible treatment options after ischemic stroke.
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Affiliation(s)
- Berta Puig
- Neurology Department, Experimental Research in Stroke and Inflammation (ERSI), University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (D.Y.); (S.B.); (T.M.)
| | - Denise Yang
- Neurology Department, Experimental Research in Stroke and Inflammation (ERSI), University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (D.Y.); (S.B.); (T.M.)
| | - Santra Brenna
- Neurology Department, Experimental Research in Stroke and Inflammation (ERSI), University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (D.Y.); (S.B.); (T.M.)
| | | | - Tim Magnus
- Neurology Department, Experimental Research in Stroke and Inflammation (ERSI), University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (D.Y.); (S.B.); (T.M.)
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