Plasma-derived extracellular vesicles from Plasmodium vivax patients signal spleen fibroblasts via NF-kB facilitating parasite cytoadherence
Plasmodium vivax is the most widely distributed human malaria parasite. Previous studies have shown that circulating microparticles during P. vivax acute attacks are indirectly associated with severity. Extracellular vesicles (EVs) are therefore major components of circulating plasma holding insights into pathological processes. Here, we demonstrate that plasma-derived EVs from Plasmodium vivax patients (PvEVs) are preferentially uptaken by human spleen fibroblasts (hSFs) as compared to the uptake of EVs from healthy individuals. Moreover, this uptake induces specific upregulation of ICAM-1 associated with the translocation of NF-kB to the nucleus. After this uptake, P. vivax-infected reticulocytes obtained from patients show specific adhesion properties to hSFs, reversed by inhibiting NF-kB translocation to the nucleus. Together, these data provide physiological EV-based insights into the mechanisms of human malaria pathology and support the existence of P. vivax-adherent parasite subpopulations in the microvasculature of the human spleen. ; We also thank the Advanced Light Microscopy Unit at the Centre for Genomic Regulation (CRG, Barcelona, Spain) for access to the Leica STED microscope. H.T. (2017FI_B1_00202) and M.D.V. (2017FI_B2_00029) are predoctoral fellows supported by Secretaria d'Universitats i Recerca del Departament d'Economia iCreixement, Generalitat de Catalunya. M.G.L. is a postdoctoral fellow supported by the Plan Estratégico (PERIS) of the Generalitat de Catalunya. I.A.H. is a predoctoral fellow supported by the Ministerio de Economia y Competitividad (FPI BES-2017081657). J.C. is supported by European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 793830. MSP3 and PHIST antibodies were generated with funding from NIH to M.R.G. (RO1A124710 and RO1AI0555994). The CRG/UPF Proteomics Unit is part of the Spanish Infrastructure for Omics Technologies (ICTS OmicsTech) and it is a member of the ProteoRed PRB3 consortium which is supported by grant PT17/0019 of the PE I+D+i 2013–2016 from the Instituto de Salud Carlos III (ISCIII) and ERDF. We acknowledge support from the Spanish Ministry of Science, Innovation and Universities, "Centro de Excelencia Severo Ochoa 2013–2017", SEV-2012-0208, and "Secretaria d'Universitats i Recerca del Departament d'Economia i Coneixement de la Generalitat de Catalunya" (2017SGR595). This research is part of ISGlobal's Programme on the Molecular Mechanisms of Malaria which is partially supported by the Fundación Ramón Areces. Work in the laboratory of Carmen Fernandez-Becerra and Hernando A del Portillo is funded by the Ministerio Español de Economía y Competitividad (SAF2016-80655-R).