Determining the role of M cells in TSE agent neuroinvasion from the intestine

Lead Research Organisation: University of Edinburgh
Department Name: The Roslin Institute

Abstract

Transmissible spongiform encephalophathies (TSEs) are prolonged diseases which cause extensive degeneration in the brain. In the absence of a cure these diseases are invariably fatal. These diseases affect both animals and humans, and include Creutzfeldt-Jakob disease (CJD) in humans, bovine spongiform encephalopathy in cattle, chronic wasting disease in mule deer and elk, and scrapie in sheep and goats.

Some animal species and humans have become infected with these diseases after eating TSE agent-contaminated food, or through lesions or cuts to the skin, mucous membranes or cornea. Many questions remain concerning the route the infectious TSE agent takes from the site of exposure (eg: skin lesions) to the brain where it causes damage to nerve cells. After exposure TSE agents appear to high-jack the immune system where they replicate in it before they then spread to the brain. This replication in the immune system is crucial for TSE agents to efficiently reach the brain where they ultimately cause nerve damage and death of the host.

Our studies show that after oral infection TSE agents target the Peyer's patches within the intestine and infect specialised cells, termed follicular dendritic cells. During TSE disease the body is unable to recognise and destroy the TSE agents. Instead, the follicular dendritic cells become infected with high levels of TSE agents. Our research shows that the infection of follicular dendritic cells by TSE agents is a crucial early step in the disease process as treatments that block TSE infection of follicular dendritic cells, block disease transmission.

How TSE agents initially infect Peyer's patches and the follicular dendritic cells within them is unknown. If we can discover how TSE agents infect these sites, we may be able to design treatments that block this ability and therefore prevent infection. The lining of the intestine is designed to prevent pathogenic microorganisms infecting the host. However, within it are specialised cells termed M cells which enable the immune system to sample the gut contents and mount an immune response if necessary. While M cells are an important component of the intestinal immune system they may also be an Achilles heal as some pathogens appear to exploit them to enter the host. Indeed some pathogens such as Salmonella may use M cells as Trojan horses to enter the body. This study will test the hypothesis that TSE agents likewise exploit M cells to gain access to Peyer's patches and infect follicular dendritic cells. If we can identify the cellular route through which TSE agents infect the host it may be possible to design treatments that block disease transmission. Currently, effective therapeutics and prophylactics to treat TSE diseases are lacking. Furthermore, no reliable preclinical diagnostic test is available. Thus a thorough understanding of the early events in TSE pathogenesis will aid the determination of risk, the development of pre-clinical diagnostics and therapeutics, especially the development vaccines against TSE agents.

Technical Summary

After oral exposure many TSE agents replicate first on follicular dendritic cells (FDC) in the gut-associated lymphoid tissues (GALT) as they spread from the site exposure (intestine) to the brain (termed, neuroinvasion). For TSE agents to replicate on FDC in the GALT after ingestion of a contaminated meal they must first cross the gut epithelium. However, the precise cellular mechanism by which TSE agents are conveyed into Peyer's patches is not known. Within the Peyer's patch epithelium are M cells, unique epithelial cells specialized for the transepithelial transport of particles. M cells are plausible sites of TSE agent transport across the gut epithelium, but definitive demonstration in vivo is lacking. This is important, as several M cell-independent mechanisms have also been proposed. A thorough understanding of the early stages of TSE pathogenesis in the GALT is crucial to determine the factors that influence the risk of infection and the identification of cellular and molecular targets for intervention. Using unique in vivo models will be used to definitively determine the role of M cells in TSE agent neuroinvasion from the intestine and test the hypothesis that M cells play a crucial role in oral TSE pathogenesis. Objective 1 tests the hypothesis that in the specific absence of M cells, TSE agent accumulation in the GALT is blocked and neuroinvasion impaired. Objective 2 aims to determine whether inflammatory stimuli that enhance M cell differentiation also enhance TSE agent uptake. Objective 3 will determine whether inflammation-mediated villous M cell expansion exacerbates TSE pathogenesis by facilitating systemic dissemination and neuroinvasion from tissues other than Peyer's patches. These data will help predict how inflammation and co-fection with gastrointestinal pathogens may influence TSE pathogenesis. This study will provide important missing data on how orally-acquired TSE agents infect the GALT during steady-state and inflammatory conditions.

Planned Impact

Researchers in industry and in academia will benefit from data in this project describing the role of M cells in TSE agent neuroinvasion from the intesine. Data describing the role of these cells in TSE disease susceptibility will aid the design of novel therapeutics, especially mucosal vaccines.

TSE diseases have had significant economic impact on the UK farming industry. Any future outbreaks of novel TSE outbreaks are likely to have huge economical impact on the food and livestock industry. Since any novel TSE outbreaks may most likely occur via the oral exposure, the farming and animal husbandry industries (farmers, breeders etc.), and food-security policy makers will have significant interest in the project's outputs.

Immunologists will be interested in data generated from this study . This is the first study to determine whether M cells and inflammatory stimuli that influence their development likewise influence susceptibility to an important orally-acquired pathogen.

UK policy makers will have interest in the project's findings on novel factors that may influence TSE susceptibility. This may influence their assessments of the risk of TSE disease transmission via oral exposure. Indeed, the applicant's recent study describing the effects of host age on TSE susceptibility (Brown et al. 2009 J. Immunol. 183, 5199) was discussed at the November 2009 meeting of the UK Spongiform Encephalopathies Advisory Committee (for minutes see http://www.seac.gov.uk/papers/103-2.pdf) and received significant media interest (eg: BBC website http://news.bbc.co.uk/1/hi/scotland/edinburgh_and_east/8307551.stm).

Depending on the data generated from this study it is plausible that pharmaceutical companies may have significant interest in data generated from this study. Therefore, during the course of the project the applicant will consult with the Institute's Business Development and Commercialisation Department to seek potential Industry partners to exploit the project's data.

This study will enable the scientists working on the project to acquire many transferable skills. Important skills will be gained in two major disciplines: mucosal immunology and TSE diseases. During the course of this study the scientist will develop import skills in in vivo biology (a currently recognised priority for research) and high resolution bioimaging. This is a collaborative project with internationally recognised researchers. As a consequence, the scientists will gain invaluable additional expertise and develop their team-working, networking and collaboration skills.

Data from this study will be disseminated to the UK and international scientific communities in a timely manner through a combination of publication in quality peer-reviewed journals and presentation at scientific meetings including: international and national scientific conferences, seminars at other research institutions and lectures to undergraduate students. Dr. Mabbott is regularly invited to present data at these events. Appropriate opportunities will be taken to communicate the project's findings to the public. Dr. Mabbott was recently involved in Public Engagement activities for Brain Awareness Week (Univ. Edinburgh). This involved teaching primary school pupils some basic biology of the human brain through short practical examples. Dr. Mabbott is keen to explore similar opportunities to communicate data from this project in a similar manner through his activities as a BBSRC-funded Schools Regional Champion. The release of potential news-worthy publications would be discussed with the Institute and BBSRC press officers and press releases issued when appropriate. Dr Mabbott's recent study in the Journal of Immunology (Brown 2009) was handled in such manner and covered by national and international media including The Times newspaper and BBC news website.

Publications

10 25 50
 
Description Many natural prion diseases are orally acquired. Following exposure via this route, the early replication of some prion strains upon follicular dendritic cells (FDC) in the Peyer's patches in the small intestine is important for the efficient spread of disease to the brain (termed neuroinvasion). However, for the prions to replicate upon the FDC within the Peyer's patches they must first cross the gut lumen. M cells are a unique population of cells within the epithelia overlying the Peyer's patches which are specialised for the transcytosis of particles and microorganisms. Our previous data suggested M cells play an important role in the initial uptake and transfer of prions from the gut lumen into Peyer's patches. Since certain pathogens and inflammatory conditions can dramatically modify the status of M cells in the gut epithelium, is it plausible that such changes may also influence oral prion disease susceptibility. In Peyer's patches stimulation by the cytokine RANKL induces the differentiation of enterocytes into M cells and maintains them in their differentiated state. Therefore, in the current study we manipulated RANKL-stimulation in the gut epithelium to modify M-cell density and studied the effects these changes had on susceptibility to oral prion infection. Mice in which RANK (the receptor for RANKL) is deleted only in the gut epithelium are deficient in M cells and unable to sample particulate antigens from the lumen. We show that in the specific absence of M cells in these mice the uptake of prions from the gut lumen and their replication upon FDC in Peyer's patches are likewise blocked. Conversely, exogenous administration of recombinant RANKL enhances M-cell differentiation within the gut epithelium and significantly enhances the uptake of particulate antigens into Peyer's patches. We also show that recombinant RANKL-mediated induction of M cells enhanced the early uptake of prions into lymphoid tissues and significantly reduced disease susceptibility. Together these data demonstrate that the density of M cells in the epithelia overlying the Peyer's patches in the small intestine has a direct influence on the uptake of prions from the gut lumen and disease susceptibility: in the specific absence of M cells prion disease susceptibility is blocked, whereas their increased density increases disease susceptibility. These data have important implications for our understanding of how changes to the gut epithelium may influence the risk of prion infection.
Exploitation Route These data identify factors which may influence the risk to oral infection with prions. These data will be of interest to stakeholders in the animal production/food industry. The findings may part explain why most human cases have affected young people, who tend to have higher numbers of M cells in their guts than older people, the researchers say. The research also suggests that the presence of other infections in the gut such as Salmonella may increase the chances of prions causing infection. Our next step is to understand how the prions exploit these cells to infect the gut. If we can design treatments to block the uptake of prions by M cells, this may provide a novel method to prevent prion infections in humans and animals.
Sectors Agriculture, Food and Drink

URL http://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1006075
 
Description BBSRC US partnering award
Amount £36,000 (GBP)
Funding ID BB/K021257/1 
Organisation Biotechnology and Biological Sciences Research Council (BBSRC) 
Sector Public
Country United Kingdom
Start 06/2013 
End 05/2017
 
Description International Travel Award Scheme
Amount £2,500 (GBP)
Funding ID BB/R012377/1 
Organisation Biotechnology and Biological Sciences Research Council (BBSRC) 
Sector Public
Country United Kingdom
Start 11/2017 
 
Description Japan Partnering Award: Defining the factors that regulate M cell-development in the intestines of livestock
Amount £42,125 (GBP)
Funding ID BB/S019294/1 
Organisation Biotechnology and Biological Sciences Research Council (BBSRC) 
Sector Public
Country United Kingdom
Start 06/2019 
End 06/2023
 
Description Study of effects of ageing on M cells
Amount £450,000 (GBP)
Funding ID BB/M024288/1 
Organisation Biotechnology and Biological Sciences Research Council (BBSRC) 
Sector Public
Country United Kingdom
Start 11/2015 
End 10/2018
 
Description Study of the immunobiology of M cells (Sehgal)
Amount £75,000 (GBP)
Funding ID EASTBIO DTP 
Organisation Biotechnology and Biological Sciences Research Council (BBSRC) 
Sector Public
Country United Kingdom
Start 09/2012 
End 08/2016
 
Title Identification of Novel Genes Selectively Expressed in the Follicle-Associated Epithelium from the Meta-Analysis of Transcriptomics Data from Multiple Mouse Cell and Tissue Populations 
Description This study provides new insight into the transcriptome of M cells in the gut epithelium 
Type Of Material Database/Collection of data 
Year Produced 2012 
Provided To Others? Yes  
Impact This study provides new insight into the FAE transcriptome. Further characterization of the candidate genes identified here will aid the identification of novel regulators of cell function in the FAE. 
URL http://www.roslin.ed.ac.uk/neil-mabbott/m-cells-and-the-fae/
 
Description Role of M cells in the sampling of mucosal antigens by B cells in Peyer's patches 
Organisation University of Gothenburg
Department Microbiology and Immunology UGOT
Country Sweden 
Sector Academic/University 
PI Contribution We provided our expertise in M cell immunobiology and use of unique in vivo systems to study M cells
Collaborator Contribution Prof. Nils Lycke is an expert in mucosal immunology and provided his unique systems in which to study the generation of antigen-specific IgA responses in the intestine.
Impact A revised manuscript has been submitted to Nature Communications (January 2019) describing how activated Peyer´s patch B cells sample antigen directly from M cells in the subepithelial dome to maintain gut germinal center responses
Start Year 2018
 
Description Study of M cell immunobiology and their role in mucosally-acquired infections 
Organisation Tohoku University
Department Graduate School of Medicine
Country Japan 
Sector Academic/University 
PI Contribution Dr. Atsushi Kobayashi worked within my research group for 2 years here at The Roslin Institute.
Collaborator Contribution Dr. Dr. Atsushi Kobayashi brought his expertise here for two years and worked as a visiting scientist in my research group.
Impact Several publications: DNA RESEARCH 19, 407-422, (2012); doi:10.1093/dnares/dss022 Mucosal Immunology 5, 216-225; doi: 10.1038/mi.2011.68 Mucosal Immunology 6, 1027-1037; doi:10.1038/mi.2012.141 Mucosal Immunology 6, 666-677; doi:10.1038/mi.2013.30
Start Year 2011
 
Description Study of M cell immunobiology and their role in mucosally-acquired infections (Emory) 
Organisation Emory University
Country United States 
Sector Academic/University 
PI Contribution We provided the ageing and prion disease pathogenesis mouse models
Collaborator Contribution Prof. Ifor Williams provided expertise in M cell immunobiology and mucosal immunology. Prof. Williams also provided unique M-cell-deficient mice (Vil1-Cre Rank-flox mice) as well as reagents to synthesise murine recombinant gst-RANKL. These were invaluable for the study of M cells in mice in vivo.
Impact Several publications: DNA RESEARCH 19, 407-422, (2012); doi:10.1093/dnares/dss022 Mucosal Immunology 5, 216-225; doi: 10.1038/mi.2011.68 Mucosal Immunology 6, 1027-1037; doi:10.1038/mi.2012.141 Mucosal Immunology 6, 666-677; doi:10.1038/mi.2013.30 Nat Nanotechnol. 2015 Apr;10(4):361-9; DOI: 10.1038/NNANO.2015.19 PLoS Pathog 12(12): e1006075; doi:10.1371/journal.ppat.1006075 Prof. WIlliams is also a named collaborator on the following BBSRC grants: BB/J014672/1 BB/M024288/1 BB/K021257/1
Start Year 2009
 
Description Study of M cell immunobiology and their role in mucosally-acquired infections (RIKEN) 
Organisation RIKEN
Department RIKEN Center for Integrative Medical Sciences (IMS)
Country Japan 
Sector Hospitals 
PI Contribution We provided the ageing and prion disease pathogenesis mouse models.
Collaborator Contribution Prof. Hiroshi Ohno and his colleagues provided expertise in M cell immunobiology.
Impact Several publications: DNA RESEARCH 19, 407-422, (2012); doi:10.1093/dnares/dss022 Mucosal Immunology 5, 216-225; doi: 10.1038/mi.2011.68 Mucosal Immunology 6, 1027-1037; doi:10.1038/mi.2012.141 Mucosal Immunology 6, 666-677; doi:10.1038/mi.2013.30 Prof. Ohno is also a named collaborator on the following BBSRC grants: BB/J014672/1 BB/M024288/1 and BBSRC Japan Partnering Award
Start Year 2007
 
Description Study of role of genes and transcription factors in M-cell development 
Organisation Keio University
Country Japan 
Sector Academic/University 
PI Contribution This collaboration aims to determine the role of genes and transcription factors in M-cell development in large animal species. Prof. Mabbott obtained a BBSRC travel award in 2017 to enable him to visit the Japanese partner Prof. Koji Hase in Tokyo, Japan, to discuss a potential collaboration. Prof. Mabbott through obtaining the travel award initiated this collaboration and provided the means to explore potential collaborations.
Collaborator Contribution Prof. Koji Hase, the Japanese partner, has provided his extensive expertise in the role of genes and transcription factors in M cell development. During my visit his institution also provided in-kind support for our meetings and small workshop. Since this visit our discussions have continued and a BBSRC Japan partnering award was submitted in November 2018 to provide further pump priming support.
Impact A BBSRC Japan partnering award was submitted in November 2018
Start Year 2017
 
Description Study of role of subepithelial mesenchymal stromal cells in M-cell development 
Organisation Hokkaido University
Country Japan 
Sector Academic/University 
PI Contribution This collaboration aims to determine the role of subepithelial mesenchymal stromal cells in M-cell development in large animal species. Prof. Mabbott obtained a BBSRC travel award in 2017 to enable him to visit the Japanese partner Prof. Sawa in Hokkaido, Japan, to discuss a potential collaboration. Prof. Mabbott through obtaining the travel award initiated this collaboration and provided the means to explore potential collaborations.
Collaborator Contribution Prof. Sawa, the Japanese partner, has provided his extensive expertise in subepithelial mesenchymal stromal cells. During my visit his institution also provided in-kind support for our meetings and small workshop. Since this visit our discussions have continued and a BBSRC Japan partnering award was submitted in November 2018 to provide further pump priming support.
Impact Submission of BBSRC Japan partnerinig award in November 2018.
Start Year 2017
 
Description Gut cells are gatekeepers of infectious brain diseases, study finds 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Media (as a channel to the public)
Results and Impact Press release via the media describing our recent research published in PLoS Pathogens
Year(s) Of Engagement Activity 2016
URL http://www.bbsrc.ac.uk/news/health/2016/161214-pr-gut-cells-gatekeepers-of-infectious-brain-diseases...
 
Description Keeping bugs at Bay: a Public Engagement Activity at the Roslin Institute 2014 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact This activity aims to teach people how the immune system fights bugs.
Year(s) Of Engagement Activity 2014
 
Description Keeping bugs at Bay: a Public Engagement Activity at the Royal Highland Show 2015 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact This activity aims to teach people how the immune system fights bugs.
Year(s) Of Engagement Activity 2015
 
Description Media comments on identification of case of BSE in a cow on an Aberdeenshire farm 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Media (as a channel to the public)
Results and Impact I was contacted by the media to provide my professional expertise and opinion on the identification of a case of bovine spongiform encephalopathy (BSE) on a Scottish farm in 2018. I provided a press statement with some information, as well as a detailed Q&A document. These were used by the media in both print and on-line articles. For example, The Herald, Daily Telegraph, Daily Mail, etc.
Year(s) Of Engagement Activity 2018
URL https://www.ed.ac.uk/roslin/news-events/latest-news/comment-on-bse-case-aberdeenshire
 
Description Scientific Writing Workshop at the Young Microbiologists Symposium, Dundee, 2016 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Postgraduate students
Results and Impact The journal PLoS Pathogens invited me to host a scientific writing workshop aimed at junior research scientists such as new post-docs or PhD students
Year(s) Of Engagement Activity 2016
URL http://www.lifesci.dundee.ac.uk/other/yms/
 
Description Visit to Iowa State University to give talk and discuss my research 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact On October 8th 2018 I gave a talk to approx. 100 post-graduate students at Iowa State University in the Immunology and Neurobiology research programmes. I also attended small workshop group sessions with the students to discuss my science and also give career advice etc.
Year(s) Of Engagement Activity 2018