Erythrocyte membrane rigidity induced by glycophorin A-ligand interaction. Evidence for a ligand-induced association between glycophorin A and skeletal proteins.

• The N-terminal subunit of MSP1 binds to a specific polypeptide region of GPA during merozoite invasion of human RBCs.• The GPA-band 3 complex plays an essential role during malaria parasite invasion.Plasmodium falciparum invasion of human red blood cells (RBCs) is an intricate process requiring a number of distinct ligand-receptor interactions at the merozoite-erythrocyte interface. Merozoite surface protein 1 (MSP1), a highly abundant ligand coating the merozoite surface in all species of malaria parasites, is essential for RBC invasion and considered a leading candidate for inclusion in a multiple-subunit vaccine against malaria. Our previous studies identified an interaction between the carboxyl-terminus of MSP1 and RBC band 3. Here, by employing phage display technology, we report a novel interaction between the amino-terminus of MSP1 and RBC glycophorin A (GPA). Mapping of the binding domains established a direct interaction between malaria MSP1 and human GPA within a region of MSP1 known to potently inhibit P falciparum invasion of human RBCs. Furthermore, a genetically modified mouse model lacking the GPA-band 3 complex in RBCs is completely resistant to malaria infection in vivo. These findings suggest an essential role of the MSP1-GPA-band 3 complex during the initial adhesion phase of malaria parasite invasion of RBCs. (Blood. 2015;125(17):2704-2711 IntroductionMalaria remains one of the most common and deadly parasitic diseases in the world. The World Health Organization estimates that 5% to 9% of the global population is infected by malaria annually, resulting in over 700 000 deaths.1 Children younger than 5 years are most vulnerable to Plasmodium falciparum, the most lethal species among 4 malaria parasites that commonly infect humans. Malaria also takes an enormous economic toll by impacting the economies of most endemic countries, particularly in sub-Saharan Africa. Historically, vaccines have been one of the most effective means of controlling infectious diseases. Accumulating evidence suggests that a malaria vaccine can be developed 2,3 ; however, most malaria vaccine candidate antigens have suffered limitations of low immunogenicity and efficacy. To date, no licensed vaccine exists for malaria despite the urgent global need.Clinical manifestation and mortality in malaria is directly associated with the blood stage of the parasite life cycle. The invasion process consists of multiple molecular events during which red blood cell (RBC) membrane proteins and merozoite-coat proteins are engaged in specific receptor-ligand interactions to form unique invasion pathways. 4,5 Continued interest in developing a multiantigen malaria vaccine has drawn much attention to parasite proteins localized on the surface and at the apical end of the merozoite as potential vaccine candidates. 4 Merozoite surface protein 1 (MSP1) is a major ligand coating the surface of merozoites in all species of malaria parasites 6 and is considered one of the leading candidates for inclusion in a multiplesubunit vaccine against...

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Merozoite surface protein 1 recognition of host glycophorin A mediates malaria parasite invasion of red blood cells

Baldwin

Hanada

et al. 2015

“…42,43 The dynamic, energy-dependent link between cell membrane and skeleton is essential for the ability of RBCs to pass rapidly through capillaries. 44,45 Maintaining optimal RBC membrane deformability is thus critical for the body to insure appropriate perfusion of the tissues by preventing trapping of less deformable RBCs in capillaries. Therefore, we next investigated the effect of CR1 ligation on RBC membrane deformability by using 2 complementary methods: (1) LOT shape recovery and (2) filtration through microchannel networks.…”

Section: Discussionmentioning

confidence: 99%

Ligation of complement receptor 1 increases erythrocyte membrane deformability

Glodek

Mirchev

Golan

et al. 2010

Microbes as well as immune complexes and other continuously generated inflammatory particles are efficiently removed from the human circulation by red blood cells (RBCs) through a process called immune-adherence clearance. During this process, RBCs use complement receptor 1 (CR1, CD35) to bind circulating complement-opsonized particles and transfer them to resident macrophages in the liver and spleen for removal. We here show that ligation of RBC CR1 by antibody and complement-opsonized particles induces a transient Ca ؉؉ influx that is proportional to the RBC CR1 levels and is inhibited by T1E3 pAb, a specific inhibitor of TRPC1 channels. The CR1-elicited RBC Ca ؉؉ influx is accompanied by an increase in RBC membrane deformability that positively correlates with the number of preexisting CR1 molecules on RBC membranes. Biochemically, ligation of RBC CR1 causes a significant increase in phosphorylation levels of ␤-spectrin that is inhibited by preincubation of RBCs with DMAT, a specific casein kinase II inhibitor. We hypothesize that the CR1-dependent increase in membrane deformability could be relevant for facilitating the transfer of CR1-bound particles from the RBCs to the hepatic and splenic phagocytes.(Blood. 2010;116(26): 6063-6071) IntroductionIn primates, in contrast to other vertebrates, clearing the intravascular space of complement-opsonized inflammatory particles (eg, microbes and immune complexes) is mediated by circulating red blood cells (RBCs) using complement receptor 1 (CR1, CD35). 1,2 During this process, known as immune-adherence clearance, RBCs immobilize complement-tagged particles and transport them to the liver and spleen where resident macrophages remove the complement-tagged particles and leave the RBCs intact. Immuneadherence clearance acts as a "buffer system," preventing deposition of circulating immune complexes in susceptible organs, such as the kidney, and preventing activation of circulating leukocytes by inflammatory particles. 3,4 We and others have also shown that CR1-mediated immune-adherence promotes more efficient phagocytosis and intracellular killing of complement-opsonized pathogens compared with opsonized pathogens that are free-floating in plasma and not RBC-bound. 5,6 We have previously found that, in circulating human RBCs, CR1 is disperse in RBC plasma membranes, and, after ligation by immune particles, interacts with Fas-associated phosphatase-1 and rearranges into large clusters. 7 Beneath the plasma membrane of RBCs, the spectrin cytoskeleton defines a series of "corrals" that are critical for maintaining RBC shape and deformability and for regulating the range and magnitude of lateral diffusion of most transmembrane proteins. 8 The mechanical attributes of the spectrin meshwork depend critically on the transient phosphorylation of ␤-spectrin, adducin, and protein 4.1R. 9-11 Therefore, we hypothesized that ligation-mediated CR1 clustering is an active process with CR1 directly affecting the phosphorylation status of cytoskeletal proteins and thus the mechanical p...

“…21 Abnormal molecular interactions that result in cross-linking of cytoskeletal proteins can markedly increase the rigidity of RBCs, as evidenced by the reduced deformability of RBCs treated with monoclonal antibodies to glycophorin A that spans the RBC membrane and interacts with spectrin through protein 4.1. 22 Although the precise mechanisms leading to decreased deformability of PRBCs are poorly understood, the contribution of parasite proteins to increased membrane rigidity is most likely attributed to their direct or indirect interactions with proteins of the RBC membrane skeleton. KAHRP is known to associate with spectrin, actin, and ankyrin in the RBC skeleton 9,23,24 and may cross-link spectrin, resulting in increased membrane rigidity.…”

Section: Discussionmentioning

confidence: 99%

Contribution of parasite proteins to altered mechanical properties of malaria-infected red blood cells

Glenister

Coppel

Cowman

et al. 2002

285

233

Red blood cells (RBCs) parasitized byPlasmodium falciparum are rigid and poorly deformable and show abnormal circulatory behavior. During parasite development, knob-associated histidinerich protein (KAHRP) and P falciparum erythrocyte membrane protein 3 (PfEMP3) are exported from the parasite and interact with the RBC membrane skeleton. Using micropipette aspiration, the membrane shear elastic modulus of RBCs infected with transgenic parasites (with kahrp or pfemp3 genes deleted) was measured to determine the contribution of these proteins to the increased rigidity of parasitized RBCs (PRBCs). In the absence of either protein, the level of membrane rigidification was significantly less than that caused by the normal parental parasite clone. KAHRP had a significantly greater effect on rigidification than PfEMP3, contributing approximately 51% of the overall increase that occurs in PRBCs compared to 15% for PfEMP3. This study provides the first quantitative information on the contribution of specific parasite proteins to altered mechanical properties of PRBCs. IntroductionMalaria caused by Plasmodium falciparum remains the most serious and widespread parasitic disease of humans. Clinical symptoms of malaria occur during the asexual stage of the parasite's life cycle, when it multiplies within red blood cells (RBCs). The extreme virulence of P falciparum and the occurrence of severe, often fatal clinical complications is related to the ability of RBCs parasitized by mature forms of the parasite to accumulate in the microvasculature of a variety of organs. 1 This abnormal circulatory behavior for RBCs appears to be directly related to parasite-induced alteration of its mechanical and adhesive properties.During the last 2 decades, the altered adhesive properties of parasitized RBCs (PRBCs) have been studied intensively (see 2,3 for recent reviews). In contrast, alterations of their mechanical properties, and the molecular mechanisms underpinning these changes, have been relatively ignored. Previous studies have clearly demonstrated that the deformability of intact PRBCs is profoundly reduced. [4][5][6] The overall increase in red cell rigidity is due, in part, to the presence of the large, nondeformable intracellular parasite and to a number of stage-specific parasite-encoded proteins that associate with the RBC membrane skeleton. 3,5,6 Paulitschke and Nash 6 used micropipette aspiration to measure the rigidity of RBCs parasitized by a number of unrelated parasite lines of knobby and knobless phenotypes. In general, the membranes of knobby PRBCs were more rigid than those lacking knobs; however, there was considerable variation in rigidity, particularly between knobby lines, with some knobby PRBCs only slightly more rigid than others infected with knobless parasite lines. Unfortunately, in their study, there was no characterization of the parasite genotype or immunohistochemical analysis of the PRBCs to determine precisely which parasite proteins were or were not expressed in different parasite lines. As such, thoug...