March, S. | Search bioRxiv

bioRxiv2024

Mapping Plasmodium transitions and interactions in the Anopheles female

The human malaria parasite, Plasmodium falciparum, relies exclusively on Anopheles mosquitoes for transmission. Once ingested during blood feeding, most parasites die in the mosquito midgut lumen or during epithelium traversal1. How surviving ookinetes interact with midgut cells and form oocysts is poorly known, yet these steps are essential to initiate a remarkable growth process culminating in the production of thousands of infectious sporozoites2. Here, using single-cell RNA sequencing of both parasites and mosquito cells across different developmental stages and metabolic conditions, we unveil key transitions and mosquito-parasite interactions occurring in the midgut. Functional analyses uncover processes regulating oocyst growth and identify the transcription factor PfSIP2 as essential for sporozoite infection of human hepatocytes. Combining shared mosquito-parasite barcode analysis with confocal microscopy, we reveal that parasites preferentially interact with midgut progenitor cells during epithelial crossing, potentially using their basal location as an exit landmark. Additionally, we show tight connections between extracellular late oocysts and surrounding muscle cells that may ensure parasites adherence to the midgut. We confirm our major findings in several mosquito-parasite combinations, including field-derived parasites. Our study provides fundamental insight into the molecular events characterizing previously inaccessible biological transitions and mosquito-parasite interactions, and identifies candidates for transmission-blocking strategies.

microbiology↗

bioRxiv2021

Gene signatures and host-parasite interactions revealed by dual single-cell profiling of Plasmodium vivax liver infection

Malaria-causing P. vivax parasites can linger in the human liver for weeks to years, and then reactivate to cause recurrent blood-stage infection. While an important target for malaria eradication, little is known about the molecular features of the replicative and non-replicative states of intracellular P. vivax parasites, or the human host-cell responses to them. Here, we leverage a bioengineered human microliver platform to culture Thai clinical isolates of P. vivax in primary human hepatocytes and conduct transcriptional profiling of infected cultures. By coupling enrichment strategies with bulk and single-cell analyses, we captured both parasite and host transcripts in individual hepatocytes throughout the infection course. We defined host- and state-dependent transcriptional signatures and identified previously unappreciated populations of replicative and non-replicative parasites, sharing features with sexual transmissive forms. We found that infection suppresses transcription of key hepatocyte function genes, and that P. vivax elicits an innate immune response that can be manipulated to control infection. Our work provides an extendible framework and resource for understanding host-parasite interactions and reveals new insights into the biology of malaria dormancy and transmission.

microbiology↗