Development of Sustainable Malaria Plasmodium vivax Lever Stage Model

Background and Aim: Vivax malaria is a global health issue challengedby undetectable dormant forms in the liver responsible for multiplerelapses. The absence of suitable models of hepatocytes permissive toPlasmodium vivax infection is responsible for the paucity of knowledgefor this type of infection and relapse mechanisms and unsuccessfulefficient drug development. In addition, genetic diversions and variableinfectivity, vector susceptibility and latency periods, which is evidentacross spatiotemporal geographical locations, skews infectivity studiesconducted without accounting for its geographical epidemiology. Toovercome these hurdles, we aim to develop a robust in vitro liver-stageassay by utilizing malaria patient-derived induced pluripotent stem cells(iPSCs) as a source of donor-specific hepatocytes and P. vivax sporozoitesobtained from the same geographical location.Methods: We undertook 5 processes; (1) Collection of blood from P.vivax mono-infected patients and generation of induced pluripotent stemcells (iPSCs) from the blood cells, (2) Production and characterization ofhepatocytes differentiated from the iPSCs, (3) Production and isolation ofP. vivax sporozoites from mosquitoes fed on P. vivax patient blood throughmembrane feeding, (4) Infection of the iPSC-derived hepatocytes with the sporozoites and detection of P. vivax, and (5) Evaluation of the infectivityand optimization of P. vivax liver stage assay with known antimalarialdrugs.Results: We have driven 3 iPSC lines each 3 malaria patients and 1non-patient. We have developed a new method of efficient hepatocytedifferentiation by monitoring hepatic gene expression, proteinexpression, enzyme functions as well as expression of malaria entrymolecule expression. In a combination of the hepatocytes and P. vivaxsporozoites produced in Anopheles mosquitos, we could develop a liverstage model. In this model, P. vivax could infect into hepatocytes andform structures as potential exoerythrocytic forms although the infectivityin our assay is still low as same as other models, and the infectivity ofhepatocytes derived from patients’ iPSCs and control ESCs or non-patientiPSCs are not significantly differentConclusion: Although there was no significant infectivity differentbetween patient and non-patient samples, this assay would be highlyreproducible and cost-effective in a study of donor-specific drugresponses and screening large compound libraries, and would pave wayfor the development of drugs targeting liver-stage malaria.

کلیدواژه ها:

iPS cells ، Malaria P. vivax ، Malaria liver stage assay