Ectopic Expression of <i>Plasmodium vivax vir</i> Genes in <i>P. falciparum</i> Affects Cytoadhesion via Increased Expression of Specific <i>var</i> Genes

oleh: Torben Rehn, Pedro Lubiana, Thi Huyen Trang Nguyen, Eva Pansegrau, Marius Schmitt, Lisa Katharina Roth, Jana Brehmer, Thomas Roeder, Dániel Cadar, Nahla Galal Metwally, Iris Bruchhaus

Format: Article
Diterbitkan: MDPI AG 2022-06-01

Deskripsi

<i>Plasmodium falciparum</i>-infected erythrocytes (<i>Pf</i>IEs) adhere to endothelial cell receptors (ECRs) of blood vessels mainly via <i>Pf</i>EMP1 proteins to escape elimination via the spleen. Evidence suggests that <i>P. vivax</i>-infected reticulocytes (<i>Pv</i>IRs) also bind to ECRs, presumably enabled by VIR proteins, as shown by inhibition experiments and studies with transgenic <i>P. falciparum</i> expressing <i>vir</i> genes. To test this hypothesis, our study investigated the involvement of VIR proteins in cytoadhesion using <i>vir</i> gene-expressing <i>P. falciparum</i> transfectants. Those VIR proteins with a putative transmembrane domain were present in Maurer’s clefts, and some were also present in the erythrocyte membrane. The VIR protein without a transmembrane domain (PVX_050690) was not exported. Five of the transgenic <i>P. falciparum</i> cell lines, including the one expressing PVX_050690, showed binding to CD36. We observed highly increased expression of specific <i>var</i> genes encoding <i>Pf</i>EMP1s in all CD36-binding transfectants. These results suggest that ectopic <i>vir</i> expression regulates <i>var</i> expression through a yet unknown mechanism. In conclusion, the observed cytoadhesion of <i>P. falciparum</i> expressing <i>vir</i> genes depended on <i>Pf</i>EMP1s, making this experimental unsuitable for characterizing VIR proteins.