Single-cell RNA sequencing ofPlasmodiumvivax sporozoites reveals stage- and species-specific transcriptomic signatures

Abstract

Plasmodium vivax sporozoites reside in the salivary glands of a mosquito before infecting a human host. Previous transcriptome-wide studies in populations of these forms were limited in their ability to elucidate cell-to-cell variation, thereby masking cellular states potentially important in understanding transmission outcomes. In this study, we performed transcription profiling on 9,947 P. vivax sporozoites to assess the extent to which they differ at single-cell resolution. We show that sporozoites residing in the mosquito’s salivary glands exist in distinct developmental states, as defined by their transcriptomic signatures. Additionally, relative to P. falciparum, P. vivax displays overlapping and unique gene usage patterns, highlighting conserved and species-specific gene programs. Notably, distinguishing P. vivax from P. falciparum were a subset of P. vivax sporozoites expressing genes associated with translational regulation and repression. Finally, our comparison of single-cell transcriptomic data from P. vivax sporozoite and erythrocytic forms reveals gene usage patterns unique to sporozoites. In defining the transcriptomic signatures of individual P. vivax sporozoites, our work provides new insights into the factors driving their developmental trajectory and lays the groundwork for a more comprehensive P. vivax cell atlas.

Single-cell RNA profiling of Plasmodium vivax-infected hepatocytes reveals parasite- and host- specific transcriptomic signatures and therapeutic targets

“…rings, sporozoites) tend to have fewer genes detected using single-cell approaches. Here, the number of genes detected, as well as the UMIs, per hypnozoite is in line with other single-cell reports assessing the transcriptomic signatures of non-replicating stages of the parasite's life cycle (Bogale et al, 2021;Howick et al, 2019;Real et al, 2021;Ruberto et al, 2021b), including hypnozoites (Mancio-Silva et al, 2022). Our transcriptome-wide assessment supports the notion that hypnozoites are metabolically active (Adams and Mueller, 2017), demonstrated by the transcription of genes associated with various biological functions including glycolysis and fatty acid metabolism.…”

“…Furthermore, the median number of UMIs per schizont (6905) was also greater in the current dataset versus other reports. The median number of genes detected per hypnozoite (519) and median number of UMIs per hypnozoite (672) were consistent with other single-cell reports assessing non-replicating, uninucleate stages (Bogale et al, 2021;Real et al, 2021;Ruberto et al, 2021a), including recent single-cell assessments of P. vivax sporozoites (Ruberto et al, 2021b)…”

“…The P. vivax PVP01 transcript information included the nucleotides encoding for the gene-flanking untranslated regions (UTRs) (Siegel, Chappell et al, 2020), which is important because of the poly-dT capture strategy of the technology used in our workflow. This information partially alleviates the challenges associated with transcription quantification (Ruberto et al, 2021b;Sà et al, 2020). Post mapping, we used the transcript information (i.e.…”

“…Single-cell RNA-sequencing (scRNA-seq) methods offer new ways of studying cell-to-cell variation (Aldridge and Teichmann, 2020), and have already allowed for novel insights into host-pathogen interactions in various disease contexts (Penaranda and Hung, 2019). In Plasmodium spp., scRNA-seq analyses have so far revealed that individual parasite forms exist on a spectrum of transcriptomic states (Bogale et al, 2021; Howick et al, 2019; Poran et al, 2017; Real et al, 2021; Reid et al, 2018; Ruberto et al, 2021a), and applying them to study the biology of P. vivax is a burgeoning area of research (Mancio-Silva et al, 2021; Ruberto et al, 2021b; Sà et al, 2020). Droplet-based techniques, such as 10x Genomics (Zheng et al, 2017), which use microfluidics, allow for the sequencing of tens to hundreds of thousands of cells, increasing the chances of observing rare cell populations (e.g., hepatocytes infected with P. vivax ).…”

Systems biology of malaria explored with nonhuman primates

“…This type of research comes with many challenges, given the need to distinguish quiescent infected cells that have low metabolic activity from developing or newly activated forms [ 217 , 218 ]. Today, such culture systems, single-cell -omic technologies [ 219 ], and cellular imaging advances [ 220 , 221 ] are paving the way for using these model systems to understand P. vivax sporozoites [ 222 ] and host–parasite interactions in infected hepatocytes, including dormant and activated hypnozoites [ 223 ].…”