A screen for Plasmodium falciparum sporozoite surface protein binding to human hepatocyte surface receptors identifies novel host–pathogen interactions

• Published in: Malaria Journal
• Main Authors: Rameswara R. Segireddy, Hugo Belda, Annie S. P. Yang, Kirsten Dundas, Julia Knoeckel, Francis Galaway, Laura Wood, Doris Quinkert, Ellen Knuepfer, Moritz Treeck, Gavin J. Wright, Alexander D. Douglas
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2024
• Subjects: Malaria; Plasmodium falciparum; Sporozoite; AVEXIS; Pf34; FGFR4; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic
• Online Access: https://doi.org/10.1186/s12936-024-04913-2; https://doaj.org/article/cd30976dbd8d4667bc3b6da3dc678722

Abstract Background Sporozoite invasion of hepatocytes is an essential step in the Plasmodium life-cycle and has similarities, at the cellular level, to merozoite invasion of erythrocytes. In the case of the Plasmodium blood-stage, efforts to identify host–pathogen protein–protein interactions have yielded important insights including vaccine candidates. In the case of sporozoite-hepatocyte invasion, the host–pathogen protein–protein interactions involved are poorly understood. Methods To gain a better understanding of the protein–protein interaction between the sporozoite ligands and host receptors, a systematic screen was performed. The previous Plasmodium falciparum and human surface protein ectodomain libraries were substantially extended, resulting in the creation of new libraries comprising 88 P. falciparum sporozoite protein coding sequences and 182 sequences encoding human hepatocyte surface proteins. Having expressed recombinant proteins from these sequences, a plate-based assay was used, capable of detecting low affinity interactions between recombinant proteins, modified for enhanced throughput, to screen the proteins for interactions. The novel interactions identified in the screen were characterized biochemically, and their essential role in parasite invasion was further elucidated using antibodies and genetically manipulated Plasmodium parasites. Results A total of 7540 sporozoite-hepatocyte protein pairs were tested under conditions capable of detecting interactions of at least 1.2 µM K D. An interaction between the human fibroblast growth factor receptor 4 (FGFR4) and the P. falciparum protein Pf34 is identified and reported here, characterizing its affinity and demonstrating the blockade of the interaction by reagents, including a monoclonal antibody. Furthermore, further interactions between Pf34 and a second P. falciparum rhoptry neck protein, PfRON6, and between human low-density lipoprotein receptor (LDLR) and the P. falciparum protein PIESP15 are identified. Conditional genetic deletion ...