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Kane SJ, Farley TK, Gordon EO, Estep J, Bender HR, Moreno JA, Bartz J, Telling GC, Pickering MC, Zabel MD. Complement Regulatory Protein Factor H Is a Soluble Prion Receptor That Potentiates Peripheral Prion Pathogenesis. J Immunol 2017; 199:3821-3827. [PMID: 29070671 DOI: 10.4049/jimmunol.1701100] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 09/29/2017] [Indexed: 01/16/2023]
Abstract
Several complement proteins exacerbate prion disease, including C3, C1q, and CD21/35. These proteins of the complement cascade likely increase uptake, trafficking, and retention of prions in the lymphoreticular system, hallmark sites of early prion propagation. Complement regulatory protein factor H (fH) binds modified host proteins and lipids to prevent C3b deposition and, thus, autoimmune cell lysis. Previous reports show that fH binds various conformations of the cellular prion protein, leading us to question the role of fH in prion disease. In this article, we report that transgenic mice lacking Cfh alleles exhibit delayed peripheral prion accumulation, replication, and pathogenesis and onset of terminal disease in a gene-dose manner. We also report a biophysical interaction between purified fH and prion rods enriched from prion-diseased brain. fH also influences prion deposition in brains of infected mice. We conclude from these data and previous findings that the interplay between complement and prions likely involves a complex balance of prion sequestration and destruction via local tissue macrophages, prion trafficking by B and dendritic cells within the lymphoreticular system, intranodal prion replication by B and follicular dendritic cells, and potential prion strain selection by CD21/35 and fH. These findings reveal a novel role for complement-regulatory proteins in prion disease.
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Affiliation(s)
- Sarah J Kane
- Prion Research Center, Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523
| | - Taylor K Farley
- Prion Research Center, Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523.,National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Elizabeth O Gordon
- Prion Research Center, Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523
| | - Joshua Estep
- Prion Research Center, Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523
| | - Heather R Bender
- Prion Research Center, Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523
| | - Julie A Moreno
- Prion Research Center, Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523
| | - Jason Bartz
- School of Medicine, Creighton University, Omaha, NE 68178; and
| | - Glenn C Telling
- Prion Research Center, Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523
| | - Matthew C Pickering
- Department of Medicine, Centre for Complement and Inflammation Research, Imperial College, London W12 0NN, United Kingdom
| | - Mark D Zabel
- Prion Research Center, Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523;
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Abstract
Prion diseases result from the misfolding of the normal, cellular prion protein (PrP(C)) to an abnormal protease resistant isomer called PrP(Res). The emergence of prion diseases in wildlife populations and their increasing threat to human health has led to increased efforts to find a treatment for these diseases. Recent studies have found numerous anti-prion compounds that can either inhibit the infectious PrP(Res) isomer or down regulate the normal cellular prion protein. However, most of these compounds do not cross the blood brain barrier to effectively inhibit PrP(Res) formation in brain tissue, do not specifically target neuronal PrP(C), and are often too toxic to use in animal or human subjects. We investigated whether siRNA delivered intravascularly and targeted towards neuronal PrP(C) is a safer and more effective anti-prion compound. This report outlines a protocol to produce two siRNA liposomal delivery vehicles, and to package and deliver PrP siRNA to neuronal cells. The two liposomal delivery vehicles are 1) complexed-siRNA liposome formulation using cationic liposomes (LSPCs), and 2) encapsulated-siRNA liposome formulation using cationic or anionic liposomes (PALETS). For the LSPCs, negatively charged siRNA is electrostatically bound to the cationic liposome. A positively charged peptide (RVG-9r [rabies virus glycoprotein]) is added to the complex, which specifically targets the liposome-siRNA-peptide complexes (LSPCs) across the blood brain barrier (BBB) to acetylcholine expressing neurons in the central nervous system (CNS). For the PALETS (peptide addressed liposome encapsulated therapeutic siRNA), the cationic and anionic lipids were rehydrated by the PrP siRNA. This procedure results in encapsulation of the siRNA within the cationic or anionic liposomes. Again, the RVG-9r neuropeptide was bound to the liposomes to target the siRNA/liposome complexes to the CNS. Using these formulations, we have successfully delivered PrP siRNA to AchR-expressing neurons, and decreased the PrP(C) expression of neurons in the CNS.
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Affiliation(s)
- Heather R Bender
- Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University
| | - Sarah Kane
- Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University
| | - Mark D Zabel
- Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University;
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