Biology subjects

Dorin-Semblat, D.

Publications and source records attributed to Dorin-Semblat, D..

2 recordsLinked to original sources

bioRxiv2025

Taurine is a Natural Host Cytoadhesion Inhibitor in Asymptomatic Malaria Cases

The prolonged dry season in malaria-endemic regions of sub-Saharan Africa can be divided into periods of high and low transmission. The majority of symptomatic malaria cases are restricted to the short high transmission period that follows the rainy season. Shortly after, persistent asymptomatic malaria cases are more prevalent throughout the prolonged low transmission period. It is still unclear whether host metabolic alterations play a role in asymptomatic infections during seasonal malaria. In this study, we analyzed the blood plasma metabolome (n=199) of individuals in The Gambia, West Africa, capturing data from both high and low malaria transmission periods. Plasma samples from individuals (n=16) were collected monthly throughout the low transmission season, enabling a longitudinal analysis of metabolic alternations over six months. Our findings reveal that significant changes in host plasma metabolite composition are associated with seasonality and malaria pathogenicity. Notably, we observed elevated levels of taurine in asymptomatic malaria infections, especially during periods of low transmission. In vitro, this naturally occurring host molecule inhibits the cytoadhesion of malaria-infected red blood cells (iRBCs), which is key to malaria disease severity and mortality. Exogenous taurine can significantly reduce or reverse binding of iRBCs to the common adhesion receptor CD36 and the endothelial protein C receptor (EPCR), the later being associated with cerebral malaria. This study uncovers a mechanism by which elevated taurine plasma levels in asymptomatic infections could reduce cytoadhesion and lead to increased splenic clearance, thereby strengthening host resistance to symptomatic infections. In the absence of health strategies targeting dry season parasite reservoirs, our findings highlight taurine as a potential prophylactic or therapeutic agent to reduce symptomatic malaria in sub-Saharan Africa. One Sentence SummaryMetabolomics uncovers taurine as a natural host inhibitor of Plasmodium falciparum cytoadhesion in asymptomatic malaria carriers, offering new insights for disease control.

microbiology↗

bioRxiv2024

Casein Kinases 2-dependent phosphorylation of the placental ligand VAR2CSA regulates Plasmodium falciparum-infected erythrocytes cytoadhesion

Placental malaria is characterized by the massive accumulation and sequestration of infected erythrocytes in the placental intervillous blood spaces, causing severe birth outcomes. The variant surface antigen VAR2CSA is associated with Plasmodium falciparum sequestration in the placenta via its capacity to adhere to chondroitin sulfate A. We have previously shown that the extracellular region of VAR2CSA is phosphorylated on several residues and that the phosphorylation enhances the adhesive properties of CSA-binding infected erythrocytes. Here, we aimed to identify the kinases mediating this phosphorylation. Here, we report that human and Plasmodium falciparum Casein Kinase 2 are involved in the phosphorylation of the extracellular region of VAR2CSA. We notably show that both CK2 can phosphorylate the extracellular region of recombinant and immunoprecipitated VAR2CSA. Mass spectrometry analysis of recombinant VAR2CSA phosphorylated by recombinant Human and P. falciparum CK2 combined with site-directed mutagenesis led to the identification of residue S1068 in VAR2CSA, which is phosphorylated by both enzymes and is associated with CSA binding. Furthermore, using CRISPR/Cas9 we generated a parasite line in which phosphoresidue, S1068, was changed to alanine. This mutation strongly impairs infected erythrocytes adhesion by abolishing VAR2CSA translocation to the surface of infected erythrocytes. We also report that two specific CK2 inhibitors reduce infected erythrocytes adhesion to CSA and decrease the phosphorylation of the recombinant extracellular region of VAR2CSA using either infected erythrocytes lysates as a source of kinases or recombinant Human and P. falciparum casein kinase 2. Taken together, these results undoubtedly demonstrate that host and P. falciparum CK2 phosphorylate the extracellular region of VAR2CSA and that this post-translational modification is important for VAR2CSA trafficking and for infected erythrocytes adhesion to CSA.

microbiology↗