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Genetic High Throughput Screenings by random mutagenesis to identify Plasmodium falciparum critical genes for asexual growth, sexual differentiation and virulence affecting host immune responses

Final Report Summary - GENETICHTS REVEAL PF (Genetic High Throughput Screenings by random mutagenesis to identify Plasmodium falciparum critical genes for asexual growth, sexual differentiation and virulence affecting host immune responses)

Malaria is a major infectious disease that causes significant morbidity and mortality, particularly in developing countries. The causative parasites, Plasmodium, are responsible for >500,000 malaria cases and >1000 deaths daily. Plasmodium drug resistance is an important problem and new drugs/targets for therapy are urgently required. While malaria represents one of the most serious global public health concerns, scientists still do not have a detailed understanding of the parasite’s lifecycle. This makes it much harder to develop effective treatments and to take preventive measures. A vaccine against malaria not only remains elusive; the effectiveness of existing treatments is diminishing as resistance increases.
Malaria parasites have several ways of dodging human immune responses. One way is by changing one at a time exposed molecules – called antigens –to resist the body’s immune response. The ability to switch antigens means it is much harder to develop a protective vaccine or effective cure. Malaria present our immune system with other challenges. After transferring from the mosquito’s salivary glands to their human hosts and after an asymptomatic hepatic infection, malaria parasites invade red blood cells, which provide them with the perfect hiding spot. When the parasites burst out of red blood cells and infect their hosts, they are exposed to our immune system for a very brief period – just a few minutes.
An EU-funded project has pioneered a new genetic approach to understanding the malaria parasite. This could help scientists to identify valuable drug targets for new anti-malarial therapies. The idea behind the GENETICHTS REVEAL PF project, which was funded through an EU Marie Curie International Re-integration Grant, was to develop and apply novel genetic methods to achieve a better understanding of the parasite’s lifecycle. The focus has been on genes responsible for asexual growth, sexual differentiation and virulence through interaction with the host immune system, with a view to eventually developing new targeted therapies. Challenges related to developing novel therapies or preventions have been largely due to a lack of understanding of the parasite’s complex lifecycle.
This work is crucial given the number of deaths caused by malaria annually, and the fact that parasite resistance against available drugs on the market has been detected. What is particularly concerning is that this resistance is spreading. Applying new techniques to better understand the parasite and identify possible targets for new, more effective therapies, could save thousands of lives.
The development of a new methodology for forward genetics via random mutagenesis, was the main aim of this project. Mutagenesis involves deliberately engineering DNA mutations to produce mutant genes or other genetically modified organisms. Various constituents of a gene can be mutated so that the functioning of a gene can be examined in detail. This allows us to directly analyse genes and better understand what the malaria parasite’s essential genes are, and essential genes are valuable drug targets for new anti-malarial therapies.’ This technique has been so far poorly exploited in Plasmodium for several technical hindrances. Our approach solved one by one each and every technical issues of the methodology, making this technique finally accessible. This appears so powerful that is even overcoming the new DNA editing system based on CRISPR/Cas9 as it produces and directly analyses essential genes. By using this technique we aimed to understand what are the essential genes in Plasmodium as they are valuable drug targets for new anti malarial therapies. IN addition we aimed to use random mutagenesis to also identify virulence factors , that are produced by Plasmodium, that impaired our natural immune responses in order to facilitate the efficacy of vaccinations.
The project’s success in developing a methodology for the random mutagenesis technique, and in advancing our understanding of how our immune cells function, will now be built upon. A library of mutated genes will be an important resource for researchers in the field moving forward.
Our work is focused on the long term impact, which can be a challenge as we live in a society where short term economic gains often influence decisions. This makes the funding we receive so important. We hope to secure further funding in order to apply our new methodology on a larger scale and make a more significant contribution to both drug discovery and vaccination.