The malaria parasite contains approximately 5,000 genes, most of whose functions remain poorly understood. This knowledge gap complicates efforts to develop new treatments against a pathogen that continues to cause significant illness and death worldwide. A research group at Umeå University is employing genetic tools to disable clusters of genes, aiming to identify which are essential for the parasite’s survival and which might serve as targets for future therapies.
The parasite’s silent takeover
When the malaria parasite infects a red blood cell, it fundamentally alters the cell’s structure. The parasite rebuilds the cell’s interior, generating new proteins and membranes that support its growth. This transformation enables the parasite to persist within the host while evading immune detection. It is also during this phase that symptoms such as fever and anemia emerge, along with severe complications like organ failure.
The Umeå University team is examining this phase of infection. Their method involves disabling multiple genes at once to determine which are necessary for the parasite’s development. The objective is not only to map gene function but also to uncover potential weaknesses that could be exploited by drugs or vaccines. Researchers have developed genetic tools to systematically knock out genes and assess their role in the parasite’s ability to grow and cause disease.
This research is labor-intensive. The parasite’s genome is large, and many of its genes have no known function. While existing tools like antimalarials, bed nets, and vaccines have reduced malaria’s impact, the parasite’s adaptability has made long-term control difficult. Genetic mapping provides a means to deepen understanding of the parasite’s biology, offering insights that could inform future interventions.
Why the red blood cell is the battleground
The malaria parasite’s most consequential activity occurs inside red blood cells. Once inside, it modifies the cell’s interior, constructing structures that facilitate nutrient import and waste export. It also alters the cell’s surface, making it adhesive so that infected cells attach to blood vessel walls—a process known as sequestration. This helps the parasite avoid destruction in the spleen.
The Umeå group’s research focuses on these surface modifications. Their work has identified proteins exported to the red blood cell membrane, including one called EMAP3, which appears on the outer surface of infected cells. While EMAP3 does not appear critical for the parasite’s growth or sequestration, its location suggests it could serve as a scaffold for displaying other proteins, including those from Plasmodium falciparum, the deadliest human malaria parasite. This finding may enable the use of Plasmodium berghei, a common laboratory model, to study aspects of the human parasite’s behavior.
The parasite’s ability to remodel red blood cells is a key factor in its ability to cause disease. If researchers can disrupt this process—by interfering with protein export or the parasite’s internal machinery—they may weaken its hold on the host. However, the challenge is substantial. The parasite’s genome is not only large but also highly adaptable, meaning that laboratory findings may not always translate to real-world effectiveness.
Genetic tools as a scalpel, not a sledgehammer
The Umeå team employs CRISPR-Cas9, a precise gene-editing tool, to disable specific genes. Their system, designed for Plasmodium berghei, allows for the simultaneous knockout of multiple genes in a single experiment. This high-throughput approach accelerates the identification of genes essential for the parasite’s survival and those that are not.
One recent advancement is a scalable CRISPR-Cas9 system that enables large-scale genetic screens. This tool has been used to study gene function in P. berghei, yielding insights that may apply to P. falciparum. Efficient screening is crucial, as mapping the parasite’s genome through traditional methods would require decades of work.
Despite these advances, the research remains complex. The parasite’s 5,000 genes interact in intricate ways, and disabling one gene may produce effects that are not immediately apparent. Some genes may compensate for the loss of others, obscuring their true importance. Others may only reveal their function under specific conditions, such as immune pressure or drug exposure.
The Umeå group’s research receives funding from the Knut and Alice Wallenberg Foundation, which has extended support through 2024. This backing highlights the long-term nature of the project. Genetic mapping is not a quick solution but a foundational step toward understanding the parasite’s biology in sufficient detail to inform the next generation of treatments.
What comes next—and what remains unknown
The Umeå team’s work is still in its early phases. While they have made progress in identifying exported proteins and developing genetic tools, many questions persist. For instance, it is unclear how the parasite regulates gene activation at different infection stages or how its genetic machinery responds to drug pressure. These questions are important because their answers could reveal new targets for intervention.
One promising direction is the use of genetic screens to identify vulnerabilities in P. falciparum. The mouse model P. berghei is useful but does not fully replicate the human parasite’s behavior. The Umeå group’s tools could help bridge this gap, allowing researchers to test hypotheses about P. falciparum’s gene function in a controlled environment.
Another challenge lies in translating genetic insights into treatments. Even if a critical gene is identified, developing a drug to target it presents a separate set of obstacles. Many antimalarials disrupt metabolic pathways, but the parasite’s ability to evolve resistance necessitates continuous innovation. Genetic mapping could reveal alternative targets—genes that are essential but have not yet been exploited by existing drugs.
The path forward is lengthy, but the Umeå group’s work provides a glimpse of what may be possible. By systematically analyzing the parasite’s genome, they are building the foundation for treatments that could one day counter malaria’s most effective survival strategies. For now, the focus remains on uncovering the parasite’s vulnerabilities, one gene and one protein at a time, until its genetic secrets are fully revealed.