Dissecting the role of host receptor context and cytoskeletal disruption in malaria parasite invasion
Lead Research Organisation:
University of Bristol
Department Name: Biochemistry
Abstract
Every year, across the world more than 200 million people contract malaria, and more than half a million people die, the majority of them children under the age of five, as a result of this disease. The parasites that cause malaria survive by attaching to the surface of and then penetrating circulating red blood cells in which they then multiply.
Red blood cells (RBCs) have a highly specialised membrane structure that results from complex interactions between proteins within the plasma membrane and a flexible underlying meshwork of protein filaments called the cytoskeleton that allow the cell to squeeze through capillaries. To penetrate the robust RBC membrane, the parasite attaches to proteins at the cell surface and induces a coordinated and localised disruption of this membrane-cytoskeletal architecture to facilitate invasion, a process that also shares some similarities with the transient disruptions required to enable RBC squeezing in the capillaries. Although several key proteins have been shown to be involved in or required for successful invasion, in the majority of cases insight into the role that these host cell proteins actually play in the invasion process is severely or completely lacking.
One of the biggest obstacles to investigating the mechanism of parasite invasion from the perspective of the host RBC is the inability to directly manipulate protein expression in these cells. Unlike most cells, RBCs contain no DNA, preventing the application of genetic techniques commonly used to manipulate protein expression in other cell types. Recent developments made in the field of RBC development (erythropoiesis) have changed this. It is now possible to culture young RBCs (reticulocytes) that are susceptible to invasion by the parasite that causes severe malaria, from an immortal cell line that allows the precursors of RBCs (erythroblasts) to be grown indefinitely or safely stored.
Excitingly, we have shown it is possible to manipulate protein expression in these nucleated cells using lentivirus and gene editing techniques to introduce changes which are maintained after the cells lose their nucleus to become RBCs. This technology can be used to prevent specific RBC proteins that are known to be involved in invasion from being expressed and also allows them to altered or replaced with mutated versions in which the localisation within the membrane, interactions with other proteins or properties of the protein itself have been changed. This technology has opened the door to the generation of RBCs with rare and even unique characteristics that can be used to explore which proteins are important for malaria parasite attachment or invasion, the importance of their membrane context and properties and how these host cell proteins participate in or are manipulated by the parasite during a successful invasion event.
This project will use RBCs with novel characteristics generated using this approach together with normal donor RBCs to investigate the mechanism of malaria parasite attachment and invasion of RBCs from a unique host cell perspective. Using a combination of malaria parasite invasion assays, biochemical and imaging techniques it will uncover how RBC proteins with crucial but poorly understood roles in invasion participate in this process. Since attachment to or stimulus of RBC receptors also induces reconfiguration or disruption of membrane-cytoskeletal protein interactions we will also investigate the involvement and modification of key cytoskeletal adaptor proteins that mediate connections between both membrane and cytoskeletal proteins. By determining the nature of and degree to which mechanisms that facilitate RBC squeezing in the capillaries and successful invasion are shared (co-opted by the parasite) or unique we will strive to identify ways in which invasion may be targeted for inhibition without impairing the normal function of the RBC within the body.
Red blood cells (RBCs) have a highly specialised membrane structure that results from complex interactions between proteins within the plasma membrane and a flexible underlying meshwork of protein filaments called the cytoskeleton that allow the cell to squeeze through capillaries. To penetrate the robust RBC membrane, the parasite attaches to proteins at the cell surface and induces a coordinated and localised disruption of this membrane-cytoskeletal architecture to facilitate invasion, a process that also shares some similarities with the transient disruptions required to enable RBC squeezing in the capillaries. Although several key proteins have been shown to be involved in or required for successful invasion, in the majority of cases insight into the role that these host cell proteins actually play in the invasion process is severely or completely lacking.
One of the biggest obstacles to investigating the mechanism of parasite invasion from the perspective of the host RBC is the inability to directly manipulate protein expression in these cells. Unlike most cells, RBCs contain no DNA, preventing the application of genetic techniques commonly used to manipulate protein expression in other cell types. Recent developments made in the field of RBC development (erythropoiesis) have changed this. It is now possible to culture young RBCs (reticulocytes) that are susceptible to invasion by the parasite that causes severe malaria, from an immortal cell line that allows the precursors of RBCs (erythroblasts) to be grown indefinitely or safely stored.
Excitingly, we have shown it is possible to manipulate protein expression in these nucleated cells using lentivirus and gene editing techniques to introduce changes which are maintained after the cells lose their nucleus to become RBCs. This technology can be used to prevent specific RBC proteins that are known to be involved in invasion from being expressed and also allows them to altered or replaced with mutated versions in which the localisation within the membrane, interactions with other proteins or properties of the protein itself have been changed. This technology has opened the door to the generation of RBCs with rare and even unique characteristics that can be used to explore which proteins are important for malaria parasite attachment or invasion, the importance of their membrane context and properties and how these host cell proteins participate in or are manipulated by the parasite during a successful invasion event.
This project will use RBCs with novel characteristics generated using this approach together with normal donor RBCs to investigate the mechanism of malaria parasite attachment and invasion of RBCs from a unique host cell perspective. Using a combination of malaria parasite invasion assays, biochemical and imaging techniques it will uncover how RBC proteins with crucial but poorly understood roles in invasion participate in this process. Since attachment to or stimulus of RBC receptors also induces reconfiguration or disruption of membrane-cytoskeletal protein interactions we will also investigate the involvement and modification of key cytoskeletal adaptor proteins that mediate connections between both membrane and cytoskeletal proteins. By determining the nature of and degree to which mechanisms that facilitate RBC squeezing in the capillaries and successful invasion are shared (co-opted by the parasite) or unique we will strive to identify ways in which invasion may be targeted for inhibition without impairing the normal function of the RBC within the body.
Technical Summary
The ultimate goal of this proposal is to understand and dissect the dynamic remodelling of the host red blood cell (RBC) membrane that occurs during malaria merozoite invasion. Using novel reticulocyte phenotypes derived through in vitro erythroid culture that comprise both domain swap hybrid surface receptor proteins and modified cytoskeletal adaptor proteins we will explore the role of host proteins in this process at both the extracellular and intracellular face of the membrane.
Whilst essential roles for several RBC membrane proteins have recently been reported, in many cases insight into the role that these host cell proteins actually play in the invasion process, extending beyond mere putative sites of attachment is severely or completely lacking. In vitro derived reticulocytes in which customised mutant and domain swap hybrid receptors basigin, CD55 and CD44 are expressed upon knockout backgrounds will enable us to determine the requirement for specific plasma membrane context, associations and mobility of these host receptors for successful invasion.
Since extracellular attachment of the merozoite to the RBC potentiates the transient cytoskeletal disruption required for invasion we will also investigate the basis of this host remodelling event. Using site specific editing of phospho-modifiable residues on adducin and other proteins we will uncover the role of cytoskeletal adaptor associations and their regulation within the host junctional complex. Through interrogation of both the invasive susceptibility and biomechanical properties of these modified cells we will determine the nature of and degree to which existing host mechanisms for regulating cell deformability are co-opted or circumvented by the parasite and identify potential approaches to target invasion without impaired capillary deformation capacity.
Whilst essential roles for several RBC membrane proteins have recently been reported, in many cases insight into the role that these host cell proteins actually play in the invasion process, extending beyond mere putative sites of attachment is severely or completely lacking. In vitro derived reticulocytes in which customised mutant and domain swap hybrid receptors basigin, CD55 and CD44 are expressed upon knockout backgrounds will enable us to determine the requirement for specific plasma membrane context, associations and mobility of these host receptors for successful invasion.
Since extracellular attachment of the merozoite to the RBC potentiates the transient cytoskeletal disruption required for invasion we will also investigate the basis of this host remodelling event. Using site specific editing of phospho-modifiable residues on adducin and other proteins we will uncover the role of cytoskeletal adaptor associations and their regulation within the host junctional complex. Through interrogation of both the invasive susceptibility and biomechanical properties of these modified cells we will determine the nature of and degree to which existing host mechanisms for regulating cell deformability are co-opted or circumvented by the parasite and identify potential approaches to target invasion without impaired capillary deformation capacity.
Publications
Capin J
(2024)
An engineered baculoviral protein and DNA co-delivery system for CRISPR-based mammalian genome editing
in Nucleic Acids Research
Karamatic Crew V
(2023)
Missense mutations in PIEZO1, which encodes the Piezo1 mechanosensor protein, define Er red blood cell antigens.
in Blood
Satchwell TJ
(2022)
Generation of red blood cells from stem cells: Achievements, opportunities and perspectives for malaria research.
in Frontiers in cellular and infection microbiology
Description | Exploring the role of Decay-accelerating factor and tight junction formation during erythrocyte invasion by Plasmodium falciparum. |
Amount | £120,000 (GBP) |
Funding ID | 227196/Z/23/Z |
Organisation | Wellcome Trust |
Sector | Charity/Non Profit |
Country | United Kingdom |
Start | 08/2022 |
End | 08/2025 |
Description | A Pint of Bloody Science - Pint of Science - The Greenbank Pub, Easton, Bristol 9th May 2022 |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Public/other audiences |
Results and Impact | A pint of science organised event on the topic of blood in a local Bristol pub. Around 50 members of the public or University students attended the talks and were able to ask questions about the research topics and there was time afterwards for general discussion with members of the public. Prof Toye gave a talk in the same session on the topic of blood transfusion and blood groups and their influence on COVID19 hospitalisation and outcomes. Introducing the concept of the structure of the red cell and the importance of blood groups and why they differ. Dr Timothy Satchwell gave a talk on Malaria Parasite Invasion - a Red Blood Cell Perspective. The talk discussed how parasites invade red blood cells. |
Year(s) Of Engagement Activity | 2022 |
URL | https://pintofscience.co.uk/event/the-human-circulatory-system-history-biology-and-disease |
Description | BBC Radio Bristol Appearance |
Form Of Engagement Activity | A press release, press conference or response to a media enquiry/interview |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Media (as a channel to the public) |
Results and Impact | Guest expert for BBC Radio Bristol segment where experts answer listeners questions. Specifically requested to answer question: Why do we have different blood types? and what is the difference between them all? with follow up questions/discussion from local radio presenter |
Year(s) Of Engagement Activity | 2022 |
Description | EMBL Conference BioMalPar XIX, Heidelberg, Germany, May 2023 |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Professional Practitioners |
Results and Impact | Talk given by Tim Satchwell on "Exploring the role of uncoupled MCT1-basigin interaction and host membrane receptor context in Plasmodium falciparum merozoite invasion" - abstract selected for oral presentation - audience 200 present + live stream and video recorded |
Year(s) Of Engagement Activity | 2023 |
Description | Gordon Red Cell Conference - Exploring the influence of media lipid source |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Professional Practitioners |
Results and Impact | Gordon Red Cell Conference - Exploring the influence of media lipid source on in vitro derived reticulocyte membrane characteristics and stability - poster presentation (TJ Satchwell - senior author) attendance 150 |
Year(s) Of Engagement Activity | 2023 |
Description | Gordon Red Cell Conference 2023 |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Professional Practitioners |
Results and Impact | Gordon Red Cell Conference - Exploring the role of uncoupled MCT1-basigin interaction and host membrane receptor context in Plasmodium falciparum merozoite invasion - poster presentation (TJ Satchwell - senior author) - attendance 150 |
Year(s) Of Engagement Activity | 2023 |
Description | Infection and Immunity Research Network: Early career Researcher's event |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Postgraduate students |
Results and Impact | Infection and Immunity Research Network: Early career Researcher's event University of Bristol, Life sciences building. Poster presentation entitled "Exploring the role of Decay-accelerating factor during red blood cell invasion by Plasmodium falciparum" |
Year(s) Of Engagement Activity | 2024 |
Description | Media fact checking around misinformation for Er blood group |
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 | Interactions with media factchecking organisations around misinformation around the Er blood group. An online influencer had reported that the discovery of the ER blood group indicated that COVID19 vacinations cause genetic alterations. This was untrue and total nonsense. Quotes were provided by Prof Toye, Dr Satchwell and NHSBT press office to correct the misinformation. Reuters and USA Today made direct contacts. https://eu.usatoday.com/story/news/factcheck/2022/12/22/fact-check-false-claim-new-er-blood-group-related-covid-19-vaccine/10928567002/ |
Year(s) Of Engagement Activity | 2022 |
URL | https://www.reuters.com/article/factcheck-er-covid-vaccines-idUSL1N33615Y |
Description | Press release announcement on the identification of the Er blood group |
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 from University of Bristol and NHS Blood and Transplant on the molecular identification as the mechanosensory protein Piezo as the Er blood group and blood group system. This is a 40 year blood group puzzle that was picked up by numerous media around the world, engaging the public and also transfusion specialists. In very rare cases this blood group has been linked to hereditary disease of the fetus and newborn (HDFN). Various articles in the general media see the list pasted below. NHSBT press release:https://www.nhsbt.nhs.uk/news/nhs-scientists-discover-new-blood-group-system/ https://www.wired.co.uk/article/new-blood-types https://www.standard.co.uk/news/health/er-new-blood-type-save-lives-pregnancies-transfusions-b1030208.html https://www.independent.co.uk/news/science/new-blood-group-er-humans-b2196867.html https://discovermagazine.com/health/theres-a-new-group-of-blood-types-heres-why-its-important https://www.sciencealert.com/discovery-of-a-new-rare-blood-type-could-save-the-lives-of-future-newborns https://interestingengineering.com/science/scientists-discover-new-set-of-blood-groups https://www.jagranjosh.com/general-knowledge/new-blood-group-detected-by-scientists-1665061284-1 https://www.bristol.ac.uk/news/2022/september/er-blood.html https://b-s-h.org.uk/about-us/news/new-blood-group-system-identified-revealing-insights-into-fatal-disease https://www.freethink.com/health/new-blood-group-mystery https://www.thestar.com.my/lifestyle/health/2022/10/16/new-blood-group-named-er-discovered https://www.techexplorist.com/scientists-discovered-rare-new-blood-group-system/53944/ https://phys.org/news/2022-10-rare-blood-group.html https://www.seattletimes.com/nation-world/scientists-discover-er-a-rare-new-blood-group-system/ https://theswaddle.com/researchers-identify-a-new-rare-blood-type/ https://www.aabb.org/news-resources/news/article/2022/10/04/nhsbt-researchers-discover-new-blood-group-system https://www.sciencealert.com/discovery-of-a-new-rare-blood-type-could-save-the-lives-of-future-newborns https://www.webmd.com/a-to-z-guides/news/20221109/scientists-discover-new-blood-types https://theconversation.com/blood-groups-there-are-way-more-than-you-think-heres-why-they-matter-191987 https://epigram.org.uk/2022/11/07/bristol-researchers-characterise-rare-new-blood-group/ https://www.nhsbt.nhs.uk/news/nhs-scientists-discover-new-blood-group-system/#:~:text=The%20newly%20discovered%20variations%20within,attacks%20their%20unborn%20child's%20blood. https://www.labmedica.com/hematology/articles/294794869/ultra-rare-set-of-blood-groups-identified.html https://www.wymt.com/2022/10/06/scientists-discover-new-set-blood-types/ (plus many more syndicate across other local TV in the US, at least 20+). https://twistedsifter.com/2022/10/scientists-investigating-rare-antigens-discover-an-entire-new-blood-group/ https://www.cbsnews.com/miami/video/scientists-discover-new-blood-types/ https://www.news18.com/news/lifestyle/researchers-find-new-blood-group-system-with-the-er-antigen-know-more-6133579.html https://www.india.com/lifestyle/new-blood-group-identified-that-poses-serious-threats-to-babies-in-pregnant-women-5675465/ https://thehill.com/changing-america/well-being/medical-advances/3673719-scientists-find-new-set-of-blood-types/ https://b-s-h.org.uk/about-us/news/new-blood-group-system-identified-revealing-insights-into-fatal-disease https://www.nhsbt.nhs.uk/news/nhs-scientists-discover-new-blood-group-system/ https://www.linkedin.com/posts/nhs-blood-and-transplant_scientists-have-discovered-a-new-set-of-blood-activity-6983476654606016513-8MhI?utm_source=share&utm_medium=member_desktop https://www.facebook.com/givebloodnhs/posts/pfbid037Ud5RUEEssmHMNh4wQRcRQMgaiJ7amNUSAMi1jxgnWq1oKBFxsQnmuMiuXigZ9Asl https://www.facebook.com/WebMD/posts/pfbid0saeqo1BewULwXaJ7NeE5KvqfFBPWw6UQPj3bucdLWtyoAbwsx7vfdSq4YaXVKzcWl https://twitter.com/BritSocHaem/status/1579457374917906432 https://twitter.com/WebMD/status/1590471800366202880 https://twitter.com/WIRED/status/1577678823633874944 https://www.fr.de/wissen/forscher-loesen-jahrzehntealtes-raetsel-neue-blutgruppe-bei-menschen-entdeckt-91850219.html https://www.difesapopolo.it/Mosaico/A-B-0-ed-ER.-La-recente-scoperta-di-un-nuovo-gruppo-sanguigno https://www.vtv.gob.ve/descubren-potencial-nueva-clasificacion-sanguineos/ https://tg24.sky.it/salute-e-benessere/2022/10/10/scoperto-nuovo-gruppo-sanguigno-er https://www.elheraldodechihuahua.com.mx/doble-via/salud/estudian-nuevos-grupos-sanguineos-para-prevenir-muerte-fetal-9073190.html https://www.lasettimanatv.it/sangue-artificiale-prima-trasfusione-in-inghilterra/ https://www.labmedica.es/hematologia/articles/294795042/identifican-un-conjunto-de-grupos-sanguineos-ultra-raros.html https://www.liputan6.com/health/read/5093225/5-fakta-tentang-er-golongan-darah-baru-yang-terdeteksi-usai-2-ibu-hamil-kehilangan-bayinya https://zdrowie.interia.pl/zdrowie/uklad-krazenia/news-przelomowe-dla-medycyny-odkrycie-naukowcow-wszystko-dzieki-s,nId,6338530 https://www.fanpage.it/innovazione/scienze/scoperto-un-nuovo-gruppo-sanguigno-er-permettera-di-salvare-vite/ https://www.businessinsider.es/descubren-nuevo-tipo-raro-sangre-podria-salvar-vidas-1136067 https://www.65ymas.com/sociedad/descubren-nuevos-grupos-sanguineos-podrian-ayudar-salvar-vidas_44033_102.html https://www.focus.pl/artykul/nowa-grupa-krwi https://www.ziaruldeiasi.ro/stiri/sangele-de-aur-cea-mai-rara-grupa-sanguina--338351.html |
Year(s) Of Engagement Activity | 2022 |
URL | https://www.bristol.ac.uk/news/2022/september/er-blood.html |
Description | Seminar given by Tim Satchwell |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Professional Practitioners |
Results and Impact | University of the West of England, October 2023. Invited by Dr. Alex Greenhough. 'Unlocking the potential of stem cell derived red blood cells: transfusion, blood group discovery and mechanisms of malaria parasite invasion' invited seminar TJ Satchwell attendance ~40 + video recorded |
Year(s) Of Engagement Activity | 2023 |
Description | Seminar in York given by Tim Satchwell |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Professional Practitioners |
Results and Impact | University of York, June 2023. Invited by Prof. Gavin Wright 'Genetic manipulation of stem cell derived red blood cells: dissecting the role of host receptor context and cytoskeletal disruption in malaria parasite invasion' invited seminar attendance ~40 |
Year(s) Of Engagement Activity | 2023 |
Description | University of Bristol 3 minute finalist Emmaline Stotter (PhD student on associated project) |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Public/other audiences |
Results and Impact | Local 3 minute thesis competition where PhD students compete to become a finalist for the National competition. Talk was also placed on youtube and social media channels (Linkedin,twitter). Emmaline Stotter was the peoples choice - where the audience vote for the best talk. |
Year(s) Of Engagement Activity | 2023 |
URL | https://www.youtube.com/watch?v=Muw9M-3X22c |