Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
, 111, 116-123

Nanoparticles Camouflaged in Platelet Membrane Coating as an Antibody Decoy for the Treatment of Immune Thrombocytopenia

Affiliations

Nanoparticles Camouflaged in Platelet Membrane Coating as an Antibody Decoy for the Treatment of Immune Thrombocytopenia

Xiaoli Wei et al. Biomaterials.

Abstract

Immune thrombocytopenia purpura (ITP) is characterized by the production of pathological autoantibodies that cause reduction in platelet counts. The disease can have serious medical consequences, leading to uncontrolled bleeding that can be fatal. Current widely used therapies for the treatment of ITP are non-specific and can, at times, result in complications that are more burdensome than the disease itself. In the present study, the use of platelet membrane-coated nanoparticles (PNPs) as a platform for the specific clearance of anti-platelet antibodies is explored. The nanoparticles, whose outer layer displays the full complement of native platelet surface proteins, act as decoys that strongly bind pathological anti-platelet antibodies in order to minimize disease burden. Here, we study the antibody binding properties of PNPs and assess the ability of the nanoparticles to neutralize antibody activity both in vitro and in vivo. Ultimately, we leverage the neutralization capacity of PNPs to therapeutically treat a murine model of antibody-induced thrombocytopenia and demonstrate considerable efficacy as shown in a bleeding time assay. PNPs represent a promising platform for the specific treatment of antibody-mediated immune thrombocytopenia by acting as an alternative target for anti-platelet antibodies, thus preserving circulating platelets with the potential of leaving broader immune function intact.

Keywords: Antibody decoy; Autoimmune disease; Biomimetic nanoparticle; Nanosponge; Platelet membrane-coated nanoparticle.

Figures

Fig. 1
Fig. 1
Schematic of platelet membrane-coated nanoparticles (PNPs) for the treatment of immune thrombocytopenia purpura (ITP). (A) To fabricate PNPs, the plasma membrane from fresh platelets is derived and then coated onto poly(lactic-co-glycolic acid) (PLGA) polymeric nanoparticle cores, transferring the surface antigenic material from the original cells onto the outside of the nanoparticles. (B) Without treatment, ITP is characterized by the binding of pathological autoantibodies to healthy platelets, resulting in their clearance by the reticuloendothelial system. (C) When PNPs are administered, they act as decoys that bind to the pathological autoantibodies, neutralizing them from circulation and enabling the survival of healthy platelets.
Fig. 2
Fig. 2
Characterization and optimization of PNPs. (A) Hydrodynamic size of bare PLGA cores, platelet vesicles, and PNPs as measured by dynamic light scattering (n = 3; mean ± SD). (B) Surface zeta potential of bare PLGA cores, platelet vesicles, and PNPs (n = 3; mean ± SD). (C) Transmission electron microscopy images of PNPs negatively stained with vanadium (scale bar = 75 nm). (D) Sizes of PNPs fabricated with varying membrane protein to PLGA weight ratios measured both immediately after synthesis in deionized water and after adjusting to 1× PBS buffer solution (n = 3; mean ± SD).
Fig. 3
Fig. 3
In vitro binding of anti-platelet antibodies to PNPs. (A) Fluorescent quantification of anti-platelet antibody binding to PNPs. A constant amount of PNPs (10 μg) was incubated with varying amounts of fluorescently labeled antibodies (n = 3; mean ± SEM). (B) Relative binding of anti-platelet antibodies to either PNPs or PEGylated nanoparticles (PEG-NPs) (n = 3; mean ± SD). (C) Relative binding of anti-platelet antibodies to PNPs in either PBS or mouse serum (n = 3; mean ± SD).
Fig. 4
Fig. 4
In vitro neutralization of anti-platelet antibodies by PNPs. (A) Representative flow cytometry histograms of platelets labeled with fluorescent anti-platelet antibodies pre-incubated with varying amounts of PNPs (from left to right: 100, 50, 20, 10, 5, and 0 μg). (B) Mean fluorescence intensity of the samples in (A) (n = 3, mean ± SD). Ctrl = no antibody. (C) Representative flow cytometry histograms of platelets labeled with fluorescent anti-platelet antibodies while concurrently incubated with varying amounts of PNPs (from left to right: 100, 50, 20, 10, 5, and 0 μg). (D) Mean fluorescence intensity of the samples in (C) (n = 3, mean ± SD). Ctrl = no antibody.
Fig. 5
Fig. 5
In vivo neutralization of anti-platelet antibody activity by PNPs. Mice were intraperitoneally administered with PBS, anti-platelet antibodies, or the antibodies pre-incubated with PNPs (n = 8; mean ± SEM). Blood was collected both before and 24 hours after administration to quantify platelet counts. ***P < 0.001, NS = not significant, Student’s t-test.
Fig. 6
Fig. 6
In vivo treatment of antibody-induced thrombocytopenia by PNPs. Mice were intraperitoneally administered with anti-platelet antibodies, followed 15 minutes later by intravenous injections of either blank solution, PNPs, or PEG-NPs via the tail vein. (A) Blood was collected both before and 24 hours after administration to quantify platelet counts (n = 8; mean ± SEM). (B) Bleeding time from the tail vein into PBS. An upper time limit of 20 minutes was established prior to initiation of the study. ***P < 0.001, Student’s t-test.

Similar articles

See all similar articles

Cited by 20 articles

See all "Cited by" articles

Publication types

MeSH terms

Substances

Feedback