A comprehensive model for assessment of liver stage therapies targeting Plasmodium vivax and Plasmodium falciparum

Alison Roth,Naresh Singh,Mélanie Rouillier,Amélie Vantaux,Amy J Conway,Swamy Rakesh Adapa,François Nosten,Case W Mcnamara,Dennis E Kyle,Silas A Davidson ,Benoã®T Witkowski ,D Noah Sather ,Caitlin Cooper ,Stefan H I Kappe,Chiara Andolina,Samantha J Barnes,Malina A Bakowski,Richard Thomson-Luque,Rays H Y Jiang,Ratawan Ubalee,Sebastian A Mikolajczak,Steven P Maher,Brice Campo,Stephen A Kaba,Victor Chaumeau,David E Lanar,John Adams

doi:10.1038/s41467-018-04221-9

Abstract

Malaria liver stages represent an ideal therapeutic target with a bottleneck in parasite load and reduced clinical symptoms; however, current in vitro pre-erythrocytic (PE) models for Plasmodium vivax and P. falciparum lack the efficiency necessary for rapid identification and effective evaluation of new vaccines and drugs, especially targeting late liver-stage development and hypnozoites. Herein we report the development of a 384-well plate culture system using commercially available materials, including cryopreserved primary human hepatocytes. Hepatocyte physiology is maintained for at least 30 days and supports development of P. vivax hypnozoites and complete maturation of P. vivax and P. falciparum schizonts. Our multimodal analysis in antimalarial therapeutic research identifies important PE inhibition mechanisms: immune antibodies against sporozoite surface proteins functionally inhibit liver stage development and ion homeostasis is essential for schizont and hypnozoite viability. This model can be implemented in laboratories in disease-endemic areas to accelerate vaccine and drug discovery research.

Highlights

IntroductionFollowing merozoite egress from the infected liver cell, the parasites escape into the hepatic vein to infect erythrocytes where they asexually replicate in circulation, leading to geometric population expansion and the clinical symptoms of malaria
We discovered that the small-scale collagen-treated surface area of particular commercially available 384-well plates coupled with our methodology provides a suitable microphysiological environment for long-term cultivation of primary human hepatocytes (PHHs) (Fig. 1a, Supplementary Fig. 1a)
This biomarker passes into hepatocytes whereupon it is trapped as cell-impermeable glutathione methylfluorescein (GS-MF) that is subsequently actively transported into the bile canaliculi

Summary

Introduction

Following merozoite egress from the infected liver cell, the parasites escape into the hepatic vein to infect erythrocytes where they asexually replicate in circulation, leading to geometric population expansion and the clinical symptoms of malaria It is the blood-stage infection that causes clinical disease, the sporozoite and the liver stage (LS) forms, which together are referred to as pre-erythrocytic (PE) stages, represent a vulnerable bottleneck for therapeutic interventions to prevent malaria[8,9]. In regards to malaria vaccinology, development of PE vaccines has focused on the initial stages of infection targeting antibodies to the sporozoite surface to neutralize parasite migration to the liver and the disease-causing blood stage[18,19,20].

Methods

Results

Conclusion