Use of Plasmodium knowlesi as a model for malaria research in vitro

Abstract

Malaria is a major human parasitic disease, responsible for more than 200 million cases and around 500,000 deaths per year worldwide. Five species of Plasmodium cause human malaria: Plasmodium falciparum, P. vivax, P. ovale, P. malariae and P. knowlesi. P. falciparum, the main cause of deaths for malaria, receives most of the attention and investments in research and control, mainly due the existence of robust long-term in vitro culture techniques. However, P. falciparum is evolutionarily and biologically distant from other species, and control measures developed against P. falciparum do not show the same efficacy when applied against other species. This fact highlights the need of specific research, especially against P. vivax, responsible for ~90% of cases in Brazil. The lack of long-term in vitro culture systems has been a challenge to P. vivax research, maintaining this species neglected worldwide. Recently P. knowlesi, a parasite evolutionary close to P. vivax, was adapted to long-term in vitro culture, offering an alternative for malaria research. This project aims to study different aspects of the biology of Plasmodium using in vitro cultures of P. knowlesi and in vivo infections of P. cynomolgi. To achieve this main goal we will work with four secondary goals: (1) development of transgenic parasites using the CRISPR/Cas9 technology; (2) evaluation of antimalarial activity of drugs in vitro; (3) molecular characterization of transcriptional regulatory sequences; and (4) use of the Single Cell RNAseq technology to identify and characterize P. knowlesi sexual stages. Results obtained will improve the understanding of the biology of P. knowlesi and P. vivax, accelerating the development of control strategies. In Brazil, there is currently no laboratory working with P. knowlesi. The establishment of this experimental model will put the country at the forefront of malaria research. (AU)