Scientists have made a new discovery that could eventually lead to more effective treatment for malaria. In a series of experiments that included using the BioXp™ system, they determined that a key phospholipid and a related protein confer protection against heat shock, allowing the parasite to survive in a host with a high fever.
Lead author Kuan-Yi Lu, senior author Emily Derbyshire, and collaborators at Duke University and MIT published their findings in the journal eLife. In the paper, they report investigating how Plasmodium falciparum responds to heat shock, since fever is one of the most challenging environmental conditions the pathogen undergoes in its human host. “Although the process by which Plasmodium copes with heat stress is unclear, a highly coordinated stress response is likely required to ensure their survival and replication under these conditions,” the scientists write.
Previous studies suggested that the multifunctional lipid regulator phosphatidylinositol 3-phosphate [PI(3)P] plays a role in protecting the parasite from some environmental stresses. Lu et al. began there, using inhibitors, knockdown models, and a CRISPR-powered tunable line to see how the phospholipid changes response to heat shock. “Through integrating chemical, biochemical, and conditional genetic approaches, we identified PfHsp70-1 to be a PI(3)P effector protein that facilitates [digestive vacuole] integrity and contributes to parasite fitness during heat shock,” the team reports.
Indeed, they found that the parasites actively produced more PI(3)P when exposed to heat stress — ranging from 1.3 times to 2.3 times the levels seen in control samples. “Our data indicates heat-shock-induced PI(3)P accumulation occurs in the mature stage parasites, which could contribute to parasite survival during malarial fever,” the scientists note.
As part of this project, the team “created a transgenic P. falciparum parasite that allowed for tunable expression of PfHsp70-1,” they report. Results showed that the phospholipid and the related protein work together to stabilize key elements in the parasite during heat stress. This tunable line, which was modified using CRISPR-Cas9, was constructed of fragments synthesized with the BioXp™ system. The donor vector was created using the Gibson Assembly® technique.
“Our research highlights the role of PI(3)P in Plasmodium biology and lays the foundation for future work aimed at elucidating the parasite stress responses in greater mechanistic detail,” the team writes, noting that these findings could also point the way to more effective use of malaria treatments.