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Riddell N, Faou P, Murphy M, Giummarra L, Downs RA, Rajapaksha H, Crewther SG. The retina/RPE proteome in chick myopia and hyperopia models: Commonalities with inherited and age-related ocular pathologies. Mol Vis 2017; 23:872-888. [PMID: 29259393 PMCID: PMC5723150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2017] [Accepted: 12/03/2017] [Indexed: 11/14/2022] Open
Abstract
Purpose Microarray and RNA sequencing studies in the chick model of early optically induced refractive error have implicated thousands of genes, many of which have also been linked to ocular pathologies in humans, including age-related macular degeneration (AMD), choroidal neovascularization, glaucoma, and cataract. These findings highlight the potential relevance of the chick model to understanding both refractive error development and the progression to secondary pathological complications. The present study aimed to determine whether proteomic responses to early optical defocus in the chick share similarities with these transcriptome-level changes, particularly in terms of dysregulation of pathology-related molecular processes. Methods Chicks were assigned to a lens condition (monocular +10 D [diopters] to induce hyperopia, -10 D to induce myopia, or no lens) on post-hatch day 5. Biometric measures were collected following a further 6 h and 48 h of rearing. The retina/RPE was then removed and prepared for liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) on an LTQ-Orbitrap Elite. Raw data were processed using MaxQuant, and differentially abundant proteins were identified using moderated t tests (fold change ≥1.5, Benjamini-Hochberg adjusted p<0.05). These differentially abundant proteins were compared with the genes and proteins implicated in previous exploratory transcriptome and proteomic studies of refractive error, as well as the genes and proteins linked to the ocular pathologies listed above for which myopia or hyperopia are risk factors. Finally, gene set enrichment analysis (GSEA) was used to assess whether gene sets from the Human Phenotype Ontology database were enriched in the lens groups relative to the no lens groups, and at the top or bottom of the protein data ranked by Spearman's correlation with refraction at 6 and 48 h. Results Refractive errors of -2.63 D ± 0.31 D (mean ± standard error, SE) and 3.90 D ± 0.37 D were evident in the negative and positive lens groups, respectively, at 6 h. By 48 h, refractive compensation to both lens types was almost complete (negative lens -9.70 D ± 0.41 D, positive lens 7.70 D ± 0.44 D). More than 140 differentially abundant proteins were identified in each lens group relative to the no lens controls at both time points. No proteins were differentially abundant between the negative and positive lens groups at 6 h, and 13 were differentially abundant at 48 h. As there was substantial overlap in the proteins implicated across the six comparisons, a total of 390 differentially abundant proteins were identified. Sixty-five of these 390 proteins had previously been implicated in transcriptome studies of refractive error animal models, and 42 had previously been associated with AMD, choroidal neovascularization, glaucoma, and/or cataract in humans. The overlap of differentially abundant proteins with AMD-associated genes and proteins was statistically significant for all conditions (Benjamini-Hochberg adjusted p<0.05), with over-representation analysis implicating ontologies related to oxidative stress, cholesterol homeostasis, and melanin biosynthesis. GSEA identified significant enrichment of genes associated with abnormal electroretinogram, photophobia, and nyctalopia phenotypes in the proteins negatively correlated with ocular refraction across the lens groups at 6 h. The implicated proteins were primarily linked to photoreceptor dystrophies and mitochondrial disorders in humans. Conclusions Optical defocus in the chicks induces rapid changes in the abundance of many proteins in the retina/RPE that have previously been linked to inherited and age-related ocular pathologies in humans. Similar changes have been identified in a meta-analysis of chick refractive error transcriptome studies, highlighting the chick as a model for the study of optically induced stress with possible relevance to understanding the development of a range of pathological states in humans.
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Affiliation(s)
- Nina Riddell
- Department of Psychology and Counselling, School of Psychology and Public Health, La Trobe University, Melbourne, VIC, Australia
| | - Pierre Faou
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Sciences, La Trobe University, Melbourne, VIC, Australia
| | - Melanie Murphy
- Department of Psychology and Counselling, School of Psychology and Public Health, La Trobe University, Melbourne, VIC, Australia
| | - Loretta Giummarra
- Department of Psychology and Counselling, School of Psychology and Public Health, La Trobe University, Melbourne, VIC, Australia
| | - Rachael A. Downs
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Sciences, La Trobe University, Melbourne, VIC, Australia
| | - Harinda Rajapaksha
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Sciences, La Trobe University, Melbourne, VIC, Australia
| | - Sheila G. Crewther
- Department of Psychology and Counselling, School of Psychology and Public Health, La Trobe University, Melbourne, VIC, Australia
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152
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What Is Our Current Understanding of PrP Sc-Associated Neurotoxicity and Its Molecular Underpinnings? Pathogens 2017; 6:pathogens6040063. [PMID: 29194372 PMCID: PMC5750587 DOI: 10.3390/pathogens6040063] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 11/21/2017] [Accepted: 11/27/2017] [Indexed: 01/15/2023] Open
Abstract
The prion diseases are a collection of fatal, transmissible neurodegenerative diseases that cause rapid onset dementia and ultimately death. Uniquely, the infectious agent is a misfolded form of the endogenous cellular prion protein, termed PrPSc. Despite the identity of the molecular agent remaining the same, PrPSc can cause a range of diseases with hereditary, spontaneous or iatrogenic aetiologies. However, the link between PrPSc and toxicity is complex, with subclinical cases of prion disease discovered, and prion neurodegeneration without obvious PrPSc deposition. The toxic mechanisms by which PrPSc causes the extensive neuropathology are still poorly understood, although recent advances are beginning to unravel the molecular underpinnings, including oxidative stress, disruption of proteostasis and induction of the unfolded protein response. This review will discuss the diseases caused by PrPSc toxicity, the nature of the toxicity of PrPSc, and our current understanding of the downstream toxic signaling events triggered by the presence of PrPSc.
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153
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Giachin G, Nepravishta R, Mandaliti W, Melino S, Margon A, Scaini D, Mazzei P, Piccolo A, Legname G, Paci M, Leita L. The mechanisms of humic substances self-assembly with biological molecules: The case study of the prion protein. PLoS One 2017; 12:e0188308. [PMID: 29161325 PMCID: PMC5697873 DOI: 10.1371/journal.pone.0188308] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 11/04/2017] [Indexed: 12/17/2022] Open
Abstract
Humic substances (HS) are the largest constituent of soil organic matter and are considered as a key component of the terrestrial ecosystem. HS may facilitate the transport of organic and inorganic molecules, as well as the sorption interactions with environmentally relevant proteins such as prions. Prions enter the environment through shedding from live hosts, facilitating a sustained incidence of animal prion diseases such as Chronic Wasting Disease and scrapie in cervid and ovine populations, respectively. Changes in prion structure upon environmental exposure may be significant as they can affect prion infectivity and disease pathology. Despite its relevance, the mechanisms of prion interaction with HS are still not completely understood. The goal of this work is to advance a structural-level picture of the encapsulation of recombinant, non-infectious, prion protein (PrP) into different natural HS. We observed that PrP precipitation upon addition of HS is mainly driven by a mechanism of "salting-out" whereby PrP molecules are rapidly removed from the solution and aggregate in insoluble adducts with humic molecules. Importantly, this process does not alter the protein folding since insoluble PrP retains its α-helical content when in complex with HS. The observed ability of HS to promote PrP insolubilization without altering its secondary structure may have potential relevance in the context of "prion ecology". These results suggest that soil organic matter interacts with prions possibly without altering the protein structures. This may facilitate prions preservation from biotic and abiotic degradation leading to their accumulation in the environment.
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Affiliation(s)
- Gabriele Giachin
- Department of Neurosciences, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
- * E-mail: (GG); (LL)
| | - Ridvan Nepravishta
- Department of Chemical Sciences and Technologies, University of Rome “Tor Vergata”, Rome, Italy
- School of Pharmacy, East Anglia University, Norwich, United Kingdom
| | - Walter Mandaliti
- Department of Chemical Sciences and Technologies, University of Rome “Tor Vergata”, Rome, Italy
| | - Sonia Melino
- Department of Chemical Sciences and Technologies, University of Rome “Tor Vergata”, Rome, Italy
| | - Alja Margon
- CREA Consiglio per la ricerca in agricoltura e l’analisi dell’economia agraria (Council for Agricultural Research and Economics), Gorizia, Italy
| | - Denis Scaini
- Life Science Department, University of Trieste, Trieste, Italy
- ELETTRA Synchrotron Light Source, Trieste, Italy
| | - Pierluigi Mazzei
- Interdepartmental Research Centre (CERMANU), University of Naples Federico II, Napoli, Italy
| | - Alessandro Piccolo
- Interdepartmental Research Centre (CERMANU), University of Naples Federico II, Napoli, Italy
| | - Giuseppe Legname
- Department of Neurosciences, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
- ELETTRA Synchrotron Light Source, Trieste, Italy
| | - Maurizio Paci
- Department of Chemical Sciences and Technologies, University of Rome “Tor Vergata”, Rome, Italy
| | - Liviana Leita
- CREA Consiglio per la ricerca in agricoltura e l’analisi dell’economia agraria (Council for Agricultural Research and Economics), Gorizia, Italy
- * E-mail: (GG); (LL)
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154
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Roguski A, Gill AC. The Role of the Mammalian Prion Protein in the Control of Sleep. Pathogens 2017; 6:pathogens6040058. [PMID: 29149024 PMCID: PMC5750582 DOI: 10.3390/pathogens6040058] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 11/08/2017] [Accepted: 11/13/2017] [Indexed: 01/09/2023] Open
Abstract
Sleep disruption is a prevalent clinical feature in many neurodegenerative disorders, including human prion diseases where it can be the defining dysfunction, as in the case of the "eponymous" fatal familial insomnia, or an early-stage symptom as in certain types of Creutzfeldt-Jakob disease. It is important to establish the role of the cellular prion protein (PrPC), the key molecule involved in prion pathogenesis, within the sleep-wake system in order to understand fully the mechanisms underlying its contribution to both healthy circadian rhythmicity and sleep dysfunction during disease. Although severe disruption to the circadian rhythm and melatonin release is evident during the pathogenic phases of some prion diseases, untangling whether PrPC plays a role in circadian rhythmicity, as suggested in mice deficient for PrPC expression, is challenging given the lack of basic experimental research. We provide a short review of the small amount of direct literature focused on the role of PrPC in melatonin and circadian rhythm regulation, as well as suggesting mechanisms by which PrPC might exert influence upon noradrenergic and dopaminergic signaling and melatonin synthesis. Future research in this area should focus upon isolating the points of dysfunction within the retino-pineal pathway and further investigate PrPC mediation of pinealocyte GPCR activity.
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Affiliation(s)
- Amber Roguski
- The Roslin Institute and Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Easter Bush Veterinary Centre, Edinburgh EH25 9RG, UK.
| | - Andrew C Gill
- The Roslin Institute and Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Easter Bush Veterinary Centre, Edinburgh EH25 9RG, UK.
- School of Chemistry, Joseph Banks Laboratories, University of Lincoln, Green Lane, Lincoln, Lincolnshire LN6 7DL, UK.
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155
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Luo XN, Song QQ, Yu J, Song J, Wang XL, Xia D, Sun P, Han J. Identification of the internal ribosome entry sites (IRES) of prion protein gene. Int J Biochem Cell Biol 2017; 93:46-51. [PMID: 29107182 DOI: 10.1016/j.biocel.2017.10.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 10/22/2017] [Accepted: 10/23/2017] [Indexed: 11/30/2022]
Abstract
Many studies demonstrated that there are several type bands of prion protein in cells. However, the formation of different prion protein bands is elusive. After several low molecular weight bands of prion protein appeared in SMB-S15 cells infected with scrapie agent Chandler, we think that IRES-dependent translation mechanism induced by prion is involved in the formation of prion protein bands. Then we designed a series of pPrP-GFP fusing plasmids and bicistronic plasmids to identify the IRES sites of prion protein gene and found 3 IRES sites inside of PrP mRNA. We also demonstrated that cap-independent translation of PrP was associated with the ER stress through Tunicamycin treatment. We still found that only IRE1 and PERK pathway regulated the IRES-dependent translation of PrP in this study. Our results indicated, we found that PrP gene had an IRES-dependent translation initiation mechanism and we successfully identified the IRESs inside of the prion protein gene.
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Affiliation(s)
- Xiao-Nuan Luo
- State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Qin-Qin Song
- State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Jie Yu
- State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Juan Song
- State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Xin-Ling Wang
- State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Dong Xia
- State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Peng Sun
- Inner Mongolia Medical University, Huhehot, China
| | - Jun Han
- State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.
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156
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α-synuclein interacts with PrP C to induce cognitive impairment through mGluR5 and NMDAR2B. Nat Neurosci 2017; 20:1569-1579. [PMID: 28945221 DOI: 10.1038/nn.4648] [Citation(s) in RCA: 193] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 08/21/2017] [Indexed: 12/20/2022]
Abstract
Synucleinopathies, such as Parkinson's disease and dementia with Lewy bodies, are neurodegenerative disorders that are characterized by the accumulation of α-synuclein (aSyn) in intracellular inclusions known as Lewy bodies. Prefibrillar soluble aSyn oligomers, rather than larger inclusions, are currently considered to be crucial species underlying synaptic dysfunction. We identified the cellular prion protein (PrPC) as a key mediator in aSyn-induced synaptic impairment. The aSyn-associated impairment of long-term potentiation was blocked in Prnp null mice and rescued following PrPC blockade. We found that extracellular aSyn oligomers formed a complex with PrPC that induced the phosphorylation of Fyn kinase via metabotropic glutamate receptors 5 (mGluR5). aSyn engagement of PrPC and Fyn activated NMDA receptor (NMDAR) and altered calcium homeostasis. Blockade of mGluR5-evoked phosphorylation of NMDAR in aSyn transgenic mice rescued synaptic and cognitive deficits, supporting the hypothesis that a receptor-mediated mechanism, independent of pore formation and membrane leakage, is sufficient to trigger early synaptic damage induced by extracellular aSyn.
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