scholarly journals Mode of action of quinoline antimalarial drugs in red blood cells infected by Plasmodium falciparum revealed in vivo

2019 ◽  
Vol 116 (46) ◽  
pp. 22946-22952 ◽  
Author(s):  
Sergey Kapishnikov ◽  
Trine Staalsø ◽  
Yang Yang ◽  
Jiwoong Lee ◽  
Ana J. Pérez-Berná ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Mode Of Action ◽  
Culture Medium ◽  
Crystal Surface ◽  
Membrane Surface ◽  
Antimalarial Drugs ◽  
Digestive Vacuole

The most widely used antimalarial drugs belong to the quinoline family. Their mode of action has not been characterized at the molecular level in vivo. We report the in vivo mode of action of a bromo analog of the drug chloroquine in rapidly frozen Plasmodium falciparum-infected red blood cells. The Plasmodium parasite digests hemoglobin, liberating the heme as a byproduct, toxic to the parasite. It is detoxified by crystallization into inert hemozoin within the parasitic digestive vacuole. By mapping such infected red blood cells with nondestructive X-ray microscopy, we observe that bromoquine caps hemozoin crystals. The measured crystal surface coverage is sufficient to inhibit further hemozoin crystal growth, thereby sabotaging heme detoxification. Moreover, we find that bromoquine accumulates in the digestive vacuole, reaching submillimolar concentration, 1,000-fold more than that of the drug in the culture medium. Such a dramatic increase in bromoquine concentration enhances the drug’s efficiency in depriving heme from docking onto the hemozoin crystal surface. Based on direct observation of bromoquine distribution in the digestive vacuole and at its membrane surface, we deduce that the excess bromoquine forms a complex with the remaining heme deprived from crystallization. This complex is driven toward the digestive vacuole membrane, increasing the chances of membrane puncture and spillage of heme into the interior of the parasite.

Ultrastructural observations on the in vitro cytoadherence of Plasmodium falciparum infected red blood cells

1990 ◽  
Vol 48 (3) ◽  
pp. 914-915
Author(s):  
D.J.P. Ferguson ◽  
A.R. Berendt ◽  
J. Tansey ◽  
K. Marsh ◽  
C.I. Newbold
Keyword(s):  
Plasmodium Falciparum ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Umbilical Vein ◽  
Cell Types ◽  
Amelanotic Melanoma ◽  
Cytoplasmic Process ◽  
Umbilical Vein Endothelial Cells

In human malaria, the most serious clinical manifestation is cerebral malaria (CM) due to infection with Plasmodium falciparum. The pathology of CM is thought to relate to the fact that red blood cells containing mature forms of the parasite (PRBC) cytoadhere or sequester to post capillary venules of various tissues including the brain. This in vivo phenomenon has been studied in vitro by examining the cytoadherence of PRBCs to various cell types and purified proteins. To date, three Ijiost receptor molecules have been identified; CD36, ICAM-1 and thrombospondin. The specific changes in the PRBC membrane which mediate cytoadherence are less well understood, but they include the sub-membranous deposition of electron-dense material resulting in surface deformations called knobs. Knobs were thought to be essential for cytoadherence, lput recent work has shown that certain knob-negative (K-) lines can cytoadhere. In the present study, we have used electron microscopy to re-examine the interactions between K+ PRBCs and both C32 amelanotic melanoma cells and human umbilical vein endothelial cells (HUVEC).We confirm previous data demonstrating that C32 cells possess numerous microvilli which adhere to the PRBC, mainly via the knobs (Fig. 1). In contrast, the HUVEC were relatively smooth and the PRBCs appeared partially flattened onto the cell surface (Fig. 2). Furthermore, many of the PRBCs exhibited an invagination of the limiting membrane in the attachment zone, often containing a cytoplasmic process from the endothelial cell (Fig. 2).

scholarly journals In Vitro Assessment of Antiplasmodial Activity and Cytotoxicity of Polyalthia longifolia Leaf Extracts on Plasmodium falciparum Strain NF54

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Bethel Kwansa-Bentum ◽  
Kojo Agyeman ◽  
Jeffrey Larbi-Akor ◽  
Claudia Anyigba ◽  
Regina Appiah-Opong
Keyword(s):  
Plasmodium Falciparum ◽  
Ethyl Acetate ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Radical Scavenging ◽  
Antimalarial Drugs ◽  
Antiplasmodial Activity ◽  
Leaf Extracts ◽  
Polyalthia Longifolia

Background. Malaria is one of the most important life-threatening infectious diseases in the tropics. In spite of the effectiveness of artemisinin-based combination therapy, reports on reduced sensitivity of the parasite to artemisinin in Cambodia and Thailand warrants screening for new potential antimalarial drugs for future use. Ghanaian herbalists claim that Polyalthia longifolia has antimalarial activity. Therefore, antiplasmodial activity, cytotoxic effects, and antioxidant and phytochemical properties of P. longifolia leaf extract were investigated in this study. Methodology/Principal Findings. Aqueous, 70% hydroethanolic and ethyl acetate leaf extracts were prepared using standard procedures. Antiplasmodial activity was assessed in vitro by using chloroquine-sensitive malaria parasite strain NF54. The SYBR® Green and tetrazolium-based calorimetric assays were used to measure parasite growth inhibition and cytotoxicity, respectively, after extract treatment. Total antioxidant activity was evaluated using a free radical scavenging assay. Results obtained showed that extracts protected red blood cells against Plasmodium falciparum mediated damage. Fifty percent inhibitory concentration (IC50) values were 24.0±1.08 μg/ml, 22.5±0.12 μg/ml, and 9.5±0.69 μg/ml for aqueous, hydroethanolic, and ethyl acetate extracts, respectively. Flavonoids, tannins, and saponins were present in the hydroethanolic extract, whereas only the latter was observed in the aqueous extract. Aqueous and hydroethanolic extracts showed stronger antioxidant activities compared to the ethyl acetate extract. Conclusions/Significance. The extracts of P. longifolia have antiplasmodial properties and low toxicities to human red blood cells. The extracts could be developed as useful alternatives to antimalarial drugs. These results support claims of the herbalists that decoctions of P. longifolia are useful antimalarial agents.

scholarly journals Rosetting of Plasmodium falciparum-infected red blood cells with uninfected red blood cells enhances microvascular obstruction under flow conditions

Blood ◽  
1991 ◽  
Vol 78 (3) ◽  
pp. 812-819 ◽  
Author(s):  
DK Kaul ◽  
EF Jr Roth ◽  
RL Nagel ◽  
RJ Howard ◽  
SM Handunnetti
Keyword(s):  
Plasmodium Falciparum ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Peripheral Resistance ◽  
Inverse Correlation ◽  
Rosette Formation ◽  
Flow Conditions ◽  
Human Red Blood Cells ◽  
Venular Endothelium

Abstract The occurrence of rosetting of Plasmodium falciparum-infected human red blood cells (IRBC) with uninfected red blood cells (RBC) and its potential pathophysiologic consequences were investigated under flow conditions using the perfused rat mesocecum vasculature. Perfusion experiments were performed using two knobby (K+) lines of P falciparum, ie, rosetting positive (K+R+) and rosetting negative (K+R-). The infusion of K+R+ IRBC resulted in higher peripheral resistance (PRU) than K+R- IRBC (P less than .0012). Video microscopy showed that under conditions of flow, in addition to cytoadherence of K+R+ IRBC to the venular endothelium, rosette formation was also restricted to venules, especially in the areas of slow flow. Rosettes were absent in arterioles and were presumably dissociated by higher wall shear rates. The presence of rosettes in the venules must therefore reflect their rapid reformation after disruption. Cytoadherence of K+R+ IRBC was characterized by formation of focal clusters along the venular wall. In addition, large aggregates of RBC were frequently observed at venular junctions, probably as a result of interaction between flowing rosettes, free IRBC, and uninfected RBC. In contrast, the infusion of K+R+ IRBC resulted in diffuse cytoadherence of these cells exclusively to the venular endothelium but not in rosetting or large aggregate formation. The cytoadherence of K+R+ IRBC showed strong inverse correlation with the venular diameter (r = -.856, P less than .00001). Incubation of K+R+ IRBC with heparin and with monoclonal antibodies to glycoprotein IV/CD36 abolished the rosette formation and resulted in decreased PRU and microvascular blockage. These findings demonstrate that rosetting of K+R+ IRBC with uninfected RBC enhances vasocclusion, suggesting an important in vivo role for rosetting in the microvascular sequestration of P falciparum-infected RBC.

scholarly journals Rosetting of Plasmodium falciparum-infected red blood cells with uninfected red blood cells enhances microvascular obstruction under flow conditions

Blood ◽  
1991 ◽  
Vol 78 (3) ◽  
pp. 812-819
Author(s):  
DK Kaul ◽  
EF Jr Roth ◽  
RL Nagel ◽  
RJ Howard ◽  
SM Handunnetti
Keyword(s):  
Plasmodium Falciparum ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Peripheral Resistance ◽  
Inverse Correlation ◽  
Rosette Formation ◽  
Flow Conditions ◽  
Human Red Blood Cells ◽  
Venular Endothelium

The occurrence of rosetting of Plasmodium falciparum-infected human red blood cells (IRBC) with uninfected red blood cells (RBC) and its potential pathophysiologic consequences were investigated under flow conditions using the perfused rat mesocecum vasculature. Perfusion experiments were performed using two knobby (K+) lines of P falciparum, ie, rosetting positive (K+R+) and rosetting negative (K+R-). The infusion of K+R+ IRBC resulted in higher peripheral resistance (PRU) than K+R- IRBC (P less than .0012). Video microscopy showed that under conditions of flow, in addition to cytoadherence of K+R+ IRBC to the venular endothelium, rosette formation was also restricted to venules, especially in the areas of slow flow. Rosettes were absent in arterioles and were presumably dissociated by higher wall shear rates. The presence of rosettes in the venules must therefore reflect their rapid reformation after disruption. Cytoadherence of K+R+ IRBC was characterized by formation of focal clusters along the venular wall. In addition, large aggregates of RBC were frequently observed at venular junctions, probably as a result of interaction between flowing rosettes, free IRBC, and uninfected RBC. In contrast, the infusion of K+R+ IRBC resulted in diffuse cytoadherence of these cells exclusively to the venular endothelium but not in rosetting or large aggregate formation. The cytoadherence of K+R+ IRBC showed strong inverse correlation with the venular diameter (r = -.856, P less than .00001). Incubation of K+R+ IRBC with heparin and with monoclonal antibodies to glycoprotein IV/CD36 abolished the rosette formation and resulted in decreased PRU and microvascular blockage. These findings demonstrate that rosetting of K+R+ IRBC with uninfected RBC enhances vasocclusion, suggesting an important in vivo role for rosetting in the microvascular sequestration of P falciparum-infected RBC.

scholarly journals THE CULTIVATION OF MALARIAL PLASMODIA (PLASMODIUM VIVAX AND PLASMODIUM FALCIPARUM) IN VITRO

1912 ◽  
Vol 16 (4) ◽  
pp. 567-579 ◽  
Author(s):  
C. C. Bass ◽  
Foster M. Johns
Keyword(s):  
Plasmodium Falciparum ◽  
Red Blood Cells ◽  
Plasmodium Vivax ◽  
Blood Cells ◽  
Distinct Species ◽  
Sexual Cycle ◽  
Successive Generations ◽  
Asexual Cycle

The asexual cycle of Plasmodium vivax and Plasmodium falciparum has been cultivated in vitro in human blood. The parasites have been grown also in red blood cells in the presence of Locke's solution, free of calcium chlorid and in the presence of ascitic fluid. The parasites grow within red blood cells and there is no evidence that they can be grown outside of these cells. The parasites are destroyed in a very few minutes in vitro by normal human serum or by all modifications of serum that we have tested. This fact, together with numerous observations of parasites in all stages of growth apparently within red cells, renders untenable the idea of extracorpuscular development. Leucocytes phagocytize and destroy malarial plasmodia growing in vitro only when the parasites escape from their red blood cell capsule or when the latter is perforated or becomes permeable. Successive generations of Plasmodium vivax and Plasmodium falciparum have been cultivated in vitro by removing the leucocytes from the culture and by transplanting to fresh red blood cells and serum at proper intervals. The asexual cycle of Plasmodium vivax and Plasmodium falciparum cultivated in vitro does not differ from the same cycle growing in vivo. The sexual cycle has not been cultivated, though we have obtained some evidence of the possibility of its accomplishment. There can no longer be any doubt that Plasmodium vivax and Plasmodium falciparum are separate and distinct species. When grown in an identical culture medium and under exactly the same conditions they remain distinct. In twenty-nine cultures of æstivo-autumnal parasites many forms and sizes have been observed, so that evidence is supplied of the occurrence of different varieties of ætivo-autumnal malarial plasmodia. The so called tertian ætivo-autumnal variety may be seen at the proper stage in all cultures grown from merozoites. The form and appearance of the same culture of plasmodia may vary greatly under different conditions which are not necessarily destructive to the parasites. Their generation period may vary from thirty hours (ætivo-autumnal) to four days (tertian), as a result of variation in the temperature at which they were cultivated. Sexual parasites grow in the cultures and are more resistant to unfavorable conditions than schizonts, often living several days after the latter die out. Forms suggesting parthenogenesis have been observed.

scholarly journals Membrane Remodelling and Vesicle Formation During Ageing of Human Red Blood Cells

2017 ◽  
Vol 42 (3) ◽  
pp. 1127-1138 ◽  
Author(s):  
Annarita Ciana ◽  
Cesare Achilli ◽  
Anjali Gaur ◽  
Giampaolo Minetti
Keyword(s):  
Red Blood Cells ◽  
Lipid Bilayer ◽  
Blood Cells ◽  
Membrane Surface ◽  
High Surface ◽  
Volume Ratio ◽  
Membrane Skeleton ◽  
Protein Marker

Background/Aims: A high surface-to-volume ratio and a spectrin membrane-skeleton (MS) confer to the mammalian red blood cells (RBCs) their characteristic deformability, mechanical strength and structural stability. During their 120 days of circulatory life in humans, RBCs decrease in size, while remaining biconcave disks, owing to a coordinated decrease in membrane surface area and cell water. It is generally believed that part of the membrane is lost with the shedding of spectrin-free vesicles of the same type that can be obtained in vitro by different treatments. If this were true, an excess of MS would arise in old RBCs, with respect to the lipid bilayer. Aim of this paper was to investigate this aspect. Methods: Quantification of spectrin by electrophoretic methods was carried out in RBCs of different age. Results: Spectrin decreases, on a per cell basis, with RBC ageing. On the other hand, the membrane raft protein marker flotillin-2, while decreasing in the membrane of old cells, was found to be strongly depleted in the membrane of in vitro-induced vesicles. Conclusion: Part of the membrane-skeleton is probably lost together with part of the lipid bilayer in a balanced way. These findings point to a mechanism for the in vivo release of membrane that is different from that which is known to occur in vitro.

scholarly journals Phosphorylation of protein 4.1 in Plasmodium falciparum-infected human red blood cells

Blood ◽  
1994 ◽  
Vol 83 (11) ◽  
pp. 3339-3345 ◽  
Author(s):  
AH Chishti ◽  
GJ Maalouf ◽  
S Marfatia ◽  
J Palek ◽  
W Wang ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Plasma Membrane ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Malaria Parasite ◽  
Malaria Parasites ◽  
Protein 4.1 ◽  
Human Red Blood Cells ◽  
Human Rbcs

The composition of the erythrocyte plasma membrane is extensively modified during the intracellular growth of the malaria parasite Plasmodium falciparum. It has been previously shown that an 80-kD phosphoprotein is associated with the plasma membrane of human red blood cells (RBCs) infected with trophozoite/schizont stage malaria parasites. However, the identity of this 80-kD phosphoprotein is controversial. One line of evidence suggests that this protein is a phosphorylated form of RBC protein 4.1 and that it forms a tight complex with the mature parasite-infected erythrocyte surface antigen. In contrast, evidence from another group indicates that the 80-kD protein is derived from the intracellular malaria parasite. To resolve whether the 80-kD protein is indeed RBC protein 4.1, we made use of RBCs obtained from a patient with homozygous 4.1(-) negative hereditary elliptocytosis. RBCs from this patient are completely devoid of protein 4.1. We report here that this lack of protein 4.1 is correlated with the absence of phosphorylation of the 80-kD protein in parasite- infected RBCs, a finding that provides conclusive evidence that the 80- kD phosphoprotein is indeed protein 4.1. In addition, we also identify and partially characterize a casein kinase that phosphorylates protein 4.1 in P falciparum-infected human RBCs. Based on these results, we suggest that the maturation of malaria parasites in human RBCs is accompanied by the phosphorylation of protein 4.1. This phosphorylation of RBC protein 4.1 may provide a mechanism by which the intracellular malaria parasite alters the mechanical properties of the host plasma membrane and modulates parasite growth and survival in vivo.

scholarly journals Peroxide Antimalarial Drugs Target Redox Homeostasis in Plasmodium falciparum Infected Red Blood Cells

2022 ◽  
Author(s):  
Ghizal Siddiqui ◽  
Carlo Giannangelo ◽  
Amanda De Paoli ◽  
Anna Katharina Schuh ◽  
Kim C. Heimsch ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Redox Homeostasis ◽  
Antimalarial Drugs

scholarly journals Phosphorylation of protein 4.1 in Plasmodium falciparum-infected human red blood cells

Blood ◽  
1994 ◽  
Vol 83 (11) ◽  
pp. 3339-3345 ◽  
Author(s):  
AH Chishti ◽  
GJ Maalouf ◽  
S Marfatia ◽  
J Palek ◽  
W Wang ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Plasma Membrane ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Malaria Parasite ◽  
Malaria Parasites ◽  
Protein 4.1 ◽  
Human Red Blood Cells ◽  
Human Rbcs

Abstract The composition of the erythrocyte plasma membrane is extensively modified during the intracellular growth of the malaria parasite Plasmodium falciparum. It has been previously shown that an 80-kD phosphoprotein is associated with the plasma membrane of human red blood cells (RBCs) infected with trophozoite/schizont stage malaria parasites. However, the identity of this 80-kD phosphoprotein is controversial. One line of evidence suggests that this protein is a phosphorylated form of RBC protein 4.1 and that it forms a tight complex with the mature parasite-infected erythrocyte surface antigen. In contrast, evidence from another group indicates that the 80-kD protein is derived from the intracellular malaria parasite. To resolve whether the 80-kD protein is indeed RBC protein 4.1, we made use of RBCs obtained from a patient with homozygous 4.1(-) negative hereditary elliptocytosis. RBCs from this patient are completely devoid of protein 4.1. We report here that this lack of protein 4.1 is correlated with the absence of phosphorylation of the 80-kD protein in parasite- infected RBCs, a finding that provides conclusive evidence that the 80- kD phosphoprotein is indeed protein 4.1. In addition, we also identify and partially characterize a casein kinase that phosphorylates protein 4.1 in P falciparum-infected human RBCs. Based on these results, we suggest that the maturation of malaria parasites in human RBCs is accompanied by the phosphorylation of protein 4.1. This phosphorylation of RBC protein 4.1 may provide a mechanism by which the intracellular malaria parasite alters the mechanical properties of the host plasma membrane and modulates parasite growth and survival in vivo.

Sign in / Sign up

Export Citation Format

Share Document