The AMA1-RON complex drives Plasmodium sporozoite invasion in the mosquito and mammalian hosts

PLoS Pathog. 2022 Jun 22;18(6):e1010643. doi: 10.1371/journal.ppat.1010643. eCollection 2022 Jun.

Abstract

Plasmodium sporozoites that are transmitted by blood-feeding female Anopheles mosquitoes invade hepatocytes for an initial round of intracellular replication, leading to the release of merozoites that invade and multiply within red blood cells. Sporozoites and merozoites share a number of proteins that are expressed by both stages, including the Apical Membrane Antigen 1 (AMA1) and the Rhoptry Neck Proteins (RONs). Although AMA1 and RONs are essential for merozoite invasion of erythrocytes during asexual blood stage replication of the parasite, their function in sporozoites was still unclear. Here we show that AMA1 interacts with RONs in mature sporozoites. By using DiCre-mediated conditional gene deletion in P. berghei, we demonstrate that loss of AMA1, RON2 or RON4 in sporozoites impairs colonization of the mosquito salivary glands and invasion of mammalian hepatocytes, without affecting transcellular parasite migration. Three-dimensional electron microscopy data showed that sporozoites enter salivary gland cells through a ring-like structure and by forming a transient vacuole. The absence of a functional AMA1-RON complex led to an altered morphology of the entry junction, associated with epithelial cell damage. Our data establish that AMA1 and RONs facilitate host cell invasion across Plasmodium invasive stages, and suggest that sporozoites use the AMA1-RON complex to efficiently and safely enter the mosquito salivary glands to ensure successful parasite transmission. These results open up the possibility of targeting the AMA1-RON complex for transmission-blocking antimalarial strategies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anopheles* / parasitology
  • Female
  • Glucans
  • Mammals
  • Merozoites / metabolism
  • Plasmodium berghei / genetics
  • Plasmodium* / metabolism
  • Protozoan Proteins / metabolism
  • Sporozoites / metabolism

Substances

  • Glucans
  • Protozoan Proteins
  • rice bran saccharide

Grant support

This work was funded by grants from the Laboratoire d’Excellence ParaFrap (ANR-11-LABX-0024 to OS), the Agence Nationale de la Recherche (ANR-16-CE15-0004 to OS and ANR-16-CE15-0010 to OS) and the Fondation pour la Recherche Médicale (EQU201903007823 to OS). The authors acknowledge the Conseil Régional d’Ile-de-France, Sorbonne Université, the National Institute for Health and Medical Research (INSERM) and the Biology, Health and Agronomy Infrastructure (IBiSA) for funding the timsTOF PRO. We acknowledge the ImagoSeine core facility of the Institut Jacques Monod, member of the France BioImaging infrastructure (ANR-10-INBS-04 to JMV) and GIS-IBiSA, and funded by the Conseil Régional d’Ile-de-France (TeneoVS to JMV). ML was supported by a ‘DIM 1Health’ doctoral fellowship awarded by the Conseil Régional d’Ile-de-France. AW is supported by the ATIP-Avenir program. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.