Plasmodium falciparum ‐induced CD36 clustering rapidly strengthens cytoadherence via p130CAS‐mediated actin cytoskeletal rearrangement

Abstract

The adhesion of infected red blood cells (IRBCs) to microvascular endothelium is critical in the pathogenesis of severe malaria. Here we used atomic force and confocal microscopy to examine the adhesive forces between IRBCs and human dermal microvascular endothelial cells. Initial contact of the cells generated a mean ± sd adhesion force of 167 ± 208 pN from the formation of single or multiple bonds with CD36. The strength of adhesion increased by 5- to 6-fold within minutes of contact through a signaling pathway initiated by CD36 ligation by live IRBCs, or polystyrene beads coated with anti-CD36 or PpMC-179, a recombinant peptide representing the minimal binding domain of the parasite ligand PfEMP1 to CD36. Engagement of CD36 led to localized phosphorylation of Src family kinases and the adaptor protein p130CAS, resulting in actin recruitment and CD36 clustering by 50-60% of adherent beads. Uninfected red blood cells or IgG-coated beads had no effect. Inhibition of the increase in adhesive strength by the Src family kinase inhibitor PP1 or gene silencing of p130CAS decreased adhesion by 39 ± 12 and 48 ± 20%, respectively, at 10 dyn/cm(2) in a flow chamber assay. Modulation of adhesive strength at PfEMP1-CD36-actin cytoskeleton synapses could be a novel target for antiadhesive therapy.

Ligand-induced growth and compaction of CD36 nanoclusters enriched in Fyn induces Fyn signaling

“…5A-D). Activation of p130Cas downstream of CD36 in this pathway has not been reported previously but has been shown in other pathways (Davis et al, 2011;Stuart et al, 2007); yet actin disruption had no impact on Fyn enrichment at CD36 clusters in the absence or presence of TSP-1, as quantified by performing TIRFM and enrichment analysis (Fig. 5E).…”

Cytoadhesion of Plasmodium falciparum–infected erythrocytes to chondroitin-4-sulfate is cooperative and shear enhanced

“…Removing adherent cells from a surface by using a micropipette or the cantilever of an atomic force microscope results in similar effects. 8,13,54 In comparison, ultrasonic pressure waves do not permit peeling effects or cell deformation. Because the noncorpuscular waves propagate at an ultrasonic speed of approximately 1640 m s 21 , the contact time is extremely short (approximately 80 ns), thereby limiting the effect on the cell to elastic interactions.…”

Dynamic interactions ofPlasmodiumspp. with vascular endothelium

“…54 Adhesion of IRBC to CD36 has been shown to recruit CD36 and actin to the site of attachment in human dermal microvascular endothelial cells through the activation of p130 CAS and Src family kinases. 56 Although there is no clear evidence of stress fiber formation, the actin cytoskeletal rearrangement may lead to a change in cell shape and hence affect the integrity of adherens junctions. Moreover, adhesion of IRBC to CD36 recruits a 5 b 1 integrin to the same site, which strengthens the adhesive force.…”