Proteomic analysis of microparticles isolated from malaria positive blood samples

Abstract

BackgroundMalaria continues to be a great public health concern due to the significant mortality and morbidity associated with the disease especially in developing countries. Microparticles (MPs), also called plasma membrane derived extracellular vesicles (PMEVs) are subcellular structures that are generated when they bud off the plasma membrane. They can be found in healthy individuals but the numbers tend to increase in pathological conditions including malaria. Although, various studies have been carried out on the protein content of specific cellular derived MPs, there seems to be paucity of information on the protein content of circulating MPs in malaria and their association with the various signs and symptoms of the disease. The aim of this study was therefore to carry out proteomic analyses of MPs isolated from malaria positive samples and compare them with proteins of MPs from malaria parasite culture supernatant and healthy controls in order to ascertain the role of MPs in malaria infection.MethodsPlasma samples were obtained from forty-three (43) malaria diagnosed patients (cases) and ten (10) healthy individuals (controls). Malaria parasite culture supernatant was obtained from our laboratory and MPs were isolated from them and confirmed using flow cytometry. 2D LC-MS was done to obtain their protein content. Resultant data were analyzed using SPSS Ver. 21.0 statistical software, Kruskal Wallis test and Spearman’s correlation coefficient r.ResultsIn all, 1806 proteins were isolated from the samples. The MPs from malaria positive samples recorded 1729 proteins, those from culture supernatant were 333 while the control samples recorded 234 proteins. The mean number of proteins in MPs of malaria positive samples was significantly higher than that in the control samples. Significantly, higher quantities of haemoglobin subunits were seen in MPs from malaria samples and culture supernatant compared to control samples.ConclusionA great number of proteins were observed to be carried in the microparticles (MPs) from malaria samples and culture supernatant compared to controls. The greater loss of haemoglobin from erythrocytes via MPs from malaria patients could serve as the initiation and progression of anaemia in P.falciparum infection. Also while some proteins were upregulated in circulating MPs in malaria samples, others were down regulated.

Proteomic analysis of extracellular vesicles from a Plasmodium falciparum Kenyan clinical isolate defines a core parasite secretome

“…8 of the 13 were also present in the Pf EV proteome described in Mantel et al 12 ( Figure 3d and Table S2 ). The shared proteins between our study and that of Millholland et al 57 were not enriched in invasion-related antigens and only one shared protein, MSP1, was an invasion related antigen ( Table S2 ). The microparticle proteome from P. falciparum infected individuals 57 included only 18 P. falciparum proteins, of which 10 were present in our Pf EV data ( Figure 3d and Table S2 ).…”

“…The shared proteins between our study and that of Millholland et al 57 were not enriched in invasion-related antigens and only one shared protein, MSP1, was an invasion related antigen ( Table S2 ). The microparticle proteome from P. falciparum infected individuals 57 included only 18 P. falciparum proteins, of which 10 were present in our Pf EV data ( Figure 3d and Table S2 ). The shared proteins largely consisted of proteins commonly identified in EVs such as heat shock proteins, while the rhoptry proteins enriched in the Pf EV proteome of the Kenyan isolate were absent ( Table S2 ).…”

“…We further compared the Pf EV proteome of the Kenyan isolate with two other published proteomes from 1) EVs released during rupture of P. falciparum schizonts 56 and 2) plasma microparticles isolated from individuals with acute P. falciparum infection 57 . For the post rupture vesicles, we downloaded two files annotated to contain data for sample type “ruptured” 56 .…”

Extracellular Vesicles Could Carry an Evolutionary Footprint in Interkingdom Communication

“…In the case of P. vivax infections, patients also show elevated levels of EVs derived from erythrocytes, platelets, leucocytes and monocytes, relative to healthy individuals (Campos et al, 2010). Proteomic analyses of circulating EVs in infected patients have identified proteins related to parasite metabolism, invasion and pathogenesis, such as enolase, Hsp 90, lactate dehydrogenase, ADP-ribosylation factor 1, phosphoglycerate kinase and merozoite surface protein 1 (Antwi-Baffour et al, 2016).…”

Extracellular Vesicles in Malaria Infection

“…Meanwhile, major parasitic protein components were involved in parasite invasion and parasite growth. 7 The EVs from P. falciparum culture supernatant are enriched with red blood cell lipid rafts proteins and membrane-associated parasite antigens, especially proteins associated with red blood cell membranes and proteins involved in parasite invasion. 8,9 These abundant parasitic proteins included the parasite proteins found in cytosol of iRBCs and exported to red cell membrane such as Maurer's clefts; the merozoite secretory proteins such as RhopH protein complex (RhopH1, RhopH2 and RhopH3), the RAP complex (RAP2 and RAP3), RALP1 and RON3; the microneme resident proteins such as EBA-175 and EBA-181; and the dense granule proteins such as HSP101, PTEX150, EXP2, SBP1, RESA, and MAHRP1.…”