2,3-Diphosphoglycerate and the Protective Effect of Pyruvate Kinase Deficiency against Malaria Infection—Exploring the Role of the Red Blood Cell Membrane

Abstract

Malaria remains a major world public health problem, contributing to poverty and inequality. It is urgent to find new efficacious tools with few adverse effects. Malaria has selected red blood cell (RBC) alterations linked to resistance against infection, and understanding the protective mechanisms involved may be useful for developing host-directed tools to control Plasmodium infection. Pyruvate kinase deficiency has been associated with resistance to malaria. Pyruvate kinase-deficient RBCs display an increased concentration of 2,3-diphosphoglycerate (2,3-DPG). We recently showed that 2,3-DPG impacts in vitro intraerythrocytic parasite growth, induces a shift of the metabolic profile of infected cells (iRBCs), making it closer to that of noninfected ones (niRBCs), and decreases the number of parasite progenies that invade new RBCs. As an increase of 2,3-DPG content may also have an adverse effect on RBC membrane and, consequently, on the parasite invasion, in this study, we explored modifications of the RBC morphology, biomechanical properties, and RBC membrane on Plasmodium falciparum in vitro cultures treated with 2,3-DPG, using atomic force microscopy (AFM)-based force spectroscopy and other experimental approaches. The presence of infection by P. falciparum significantly increased the rigidity of parasitized cells and influenced the morphology of RBCs, as parasitized cells showed a decrease of the area-to-volume ratio. The extracellular addition of 2,3-DPG also slightly affected the stiffness of niRBCs, making it more similar to that of infected cells. It also changed the niRBC height, making the cells appear more elongated. Moreover, 2,3-DPG treatment influenced the cell surface charge, becoming more negative in treated RBCs than in untreated ones. The results indicate that treatment with 2,3-DPG has only a mild effect on RBCs in comparison with the effect of the presence of the parasite on the host cell. 2,3-DPG is an endogenous host metabolite, which may, in the future, originate a new antimalarial tool with few adverse effects on noninfected cells.

Differential Gene Expression of Malaria Parasite in Response to Red Blood Cell-Specific Glycolytic Intermediate 2,3-Diphosphoglycerate (2,3-DPG)

“…Earlier studies have also demonstrated that 2,3-DPG's impact on RBC deformability and membrane zeta potential was relatively minor, and these changes did not impede effective parasite re-invasion or egress. Moreover, cytotoxicity remained low, with no discernible alterations in ATP levels and no noticeable effect on the parasite when RBCs were subjected to 2,3-DPG treatment before infection [15,16]. We hypothesize that a distinct entry mechanism for exogenous 2,3-DPG in infected and non-infected RBCs may occur.…”

“…Previous results showed that addition of 2,3-DPG to an in vitro P. falciparum culture medium significantly impaired the parasite's intraerythrocytic developmental cycle (IDC), the metabolic profile of 2,3-DPG-treated infected cells became more similar to that of non-infected cells, and host cells were not significantly affected. Also, parasites exposed to 2,3-DPG produced significantly fewer progeny, independently of the ATP level inside the cell [15,16]. Therefore, to confirm these preliminary results and understand the biological processes involved in this response, in this study, we analyzed the differential gene expression and the transcriptomic profile of schizogonic P. falciparum trophozoites from in vitro cultures subjected or not subjected to the action of 2,3-DPG, using Nanopore Sequencing Technology.…”

Advances in Human Pathogen Control—A 21st Century Challenge

“…Infections caused by the protozoa Plasmodium falciparum and Trypanosoma cruzi , the causative agents of malaria and Chagas disease, were also the subject of two papers. Carvalho and co-authors [ 9 ] investigated the association between pyruvate kinase deficiency and resistance to malaria. The authors used atomic force microscopy and other experimental approaches to investigate modifications of red blood cell morphology, membranes, and biomechanical properties on in vitro cultures of Plasmodium falciparum treated with 2,3-diphosphoglycerate [ 9 ].…”

“…Carvalho and co-authors [ 9 ] investigated the association between pyruvate kinase deficiency and resistance to malaria. The authors used atomic force microscopy and other experimental approaches to investigate modifications of red blood cell morphology, membranes, and biomechanical properties on in vitro cultures of Plasmodium falciparum treated with 2,3-diphosphoglycerate [ 9 ]. The results indicate that 2,3-diphosphoglycerate has only a mild effect on red blood cells when compared with the presence of the parasite on the host cell.…”

“…The results indicate that 2,3-diphosphoglycerate has only a mild effect on red blood cells when compared with the presence of the parasite on the host cell. The authors anticipate that, in the future, diphosphoglycerate may be exploited to design a new antimalarial tool [ 9 ]. Banga and co-authors work call attention to the urgent need to identify pathways and targets to develop novel drugs against Trypanosoma cruzi [ 10 ].…”