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

Innovative strategies to control malaria are urgently needed. Exploring the interplay between Plasmodium sp. parasites and host red blood cells (RBCs) offers opportunities for novel antimalarial interventions. Pyruvate kinase deficiency (PKD), characterized by heightened 2,3-diphosphoglycerate (2,3-DPG) concentration, has been associated with protection against malaria. Elevated levels of 2,3-DPG, a specific mammalian metabolite, may hinder glycolysis, prompting us to hypothesize its potential contribution to PKD-mediated protection. We investigated the impact of the extracellular supplementation of 2,3-DPG on the Plasmodium falciparum intraerythrocytic developmental cycle in vitro. The results showed an inhibition of parasite growth, resulting from significantly fewer progeny from 2,3-DPG-treated parasites. We analyzed differential gene expression and the transcriptomic profile of P. falciparum trophozoites, from in vitro cultures subjected or not subjected to the action of 2,3-DPG, using Nanopore Sequencing Technology. The presence of 2,3-DPG in the culture medium was associated with the significant differential expression of 71 genes, mostly associated with the GO terms nucleic acid binding, transcription or monoatomic anion channel. Further, several genes related to cell cycle control were downregulated in treated parasites. These findings suggest that the presence of this RBC-specific glycolytic metabolite impacts the expression of genes transcribed during the parasite trophozoite stage and the number of merozoites released from individual schizonts, which supports the potential role of 2,3-DPG in the mechanism of protection against malaria by PKD.

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

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.

Synthetic Red Blood Cell-Specific Glycolytic Intermediate 2,3-Diphosphoglycerate (2,3-DPG) Inhibits Plasmodium falciparum Development In Vitro.

Mechanisms of malaria parasite interaction with its host red blood cell may provide potential targets for new antimalarial approaches. Pyruvate kinase deficiency has been associated with resistance to malaria in both experimental models and population studies. Two of the major pyruvate kinase deficient-cell disorders are the decrease in ATP and the increase in 2,3-biphosphoglycerate (2,3-BPG) concentration. High levels of this metabolite, only present in mammalian red blood cell, has an inhibitory effect on glycolysis and we hypothesized that its accumulation may also be harmful to the parasite and be involved in the mechanism of protection provided by that enzymopathy. We examined the effect of a synthetic form, 2,3-DPG, on the Plasmodium falciparum intraerythrocytic developmental cycle in vitro. Results showed an impairment of parasite growth with a direct effect on parasite maturation as significant lower progeny emerged from parasites that were submitted to 2,3-DPG. Further, adding the compound to the culture medium did not result in any effect on the host cell, but instead the metabolic profile of an infected cell became closer to that of a non-infected cell.

Tratamento de hemangioma gigante com interferon alfa: relato de dois casos / Treatment of giant hemangioma with interferon-alpha: report of two cases

O objetivo do trabalho é descrever o uso de interferon alfa no tratamento de pacientes com hemangioma gigante. Os autores relatam e analisam dois casos de hemangioma gigante em tratamento com interferon alfa. IBS, 3 anos, em acompanhamento no Ambulatório de Hematologia desde um ano de idade com quadro de lesão angiomatosa em praticamente toda hemiface direita, acompanhada de sangramentos gengivais importantes. Após a realização de exames complementares (Angiorressonância magnética) e feito o diagnóstico de hemangioma gigante em face, foi iniciado tratamento com prednisona e, posteriormente, associação com interferon alfa e observada importante melhora do quadro, resultando na diminuição dos episódios de sangramento e no tamanho do tumor. C.N.P., 12 anos, apresentando nódulo em região lateral de joelho esquerdo há 2 anos, com aumento progressivo do tamanho e dor local. Fez uso de prednisona e, sem melhora do quadro, introduzido interferon alfa com regressão importante do tamanho do tumor. O tratamento com interferon alfa deve ser considerado no tratamento de hemangiomas, pois apresenta bons resultados em relação à diminuição do tamanho do tumor e, conseqüentemente, reduz as intercorrências clínicas associadas à sua presença, principalmente os sangramentos.

The aim of this study is to describe the treatment using interferon-alpha of giant hemangiomas in children. The authors report two cases of children presenting with giant hemangiomas treated using interferon-alpha and analyze the results. IBS, 3 years-old, has been followed up in Famema Hemathology Service since she was 1 year-old with a tumor on the face and persistent bleeding. After clinical and radiologic evaluations and suggested the diagnosis of giant hemangioma, she started treatment with interferon-alpha. A great clinical improvement was observed a reducing of the number of episodes of bleedings and a decrease in of the tumor size. CNP, 12 years-old, came to this service in the last year presenting with a small painful tumor on the left knee. She had already tried a treatment with Prednisone with no improvement. Treatment with interferon-alpha was initiated with a significant decrease in its size. The use of interferon-alpha should be considered in the treatment of giant hemangioma due to its favorable results related to a reduction in the tumor size and the episodes of bleeding.