title: The functional dissection of the plasma corona of SiO₂-NPs spots histidine rich glycoprotein as a major player able to hamper nanoparticle capture by macrophages.
abstract: A coat of strongly-bound host proteins, or hard corona, may influence the biological and pharmacological features of nanotheranostics by altering their cell-interaction selectivity and macrophage clearance. With the goal of identifying specific corona-effectors, we investigated how the capture of amorphous silica nanoparticles (SiO2-NPs; Ø = 26 nm; zeta potential = -18.3 mV) by human lymphocytes, monocytes and macrophages is modulated by the prominent proteins of their plasma corona. LC MS/MS analysis, western blotting and quantitative SDS-PAGE densitometry show that Histidine Rich Glycoprotein (HRG) is the most abundant component of the SiO2-NP hard corona in excess plasma from humans (HP) and mice (MP), together with minor amounts of the homologous Kininogen-1 (Kin-1), while it is remarkably absent in their Foetal Calf Serum (FCS)-derived corona. HRG binds with high affinity to SiO2-NPs (HRG Kd ∼2 nM) and competes with other plasma proteins for the NP surface, so forming a stable and quite homogeneous corona inhibiting nanoparticles binding to the macrophage membrane and their subsequent uptake. Conversely, in the case of lymphocytes and monocytes not only HRG but also several common plasma proteins can interchange in this inhibitory activity. The depletion of HRG and Kin-1 from HP or their plasma exhaustion by increasing NP concentration (>40 μg ml(-1) in 10% HP) lead to a heterogeneous hard corona, mostly formed by fibrinogen (Fibr), HDLs, LDLs, IgGs, Kallikrein and several minor components, allowing nanoparticle binding to macrophages. Consistently, the FCS-derived SiO2-NP hard corona, mainly formed by hemoglobin, α2 macroglobulin and HDLs but lacking HRG, permits nanoparticle uptake by macrophages. Moreover, purified HRG competes with FCS proteins for the NP surface, inhibiting their recruitment in the corona and blocking NP macrophage capture. HRG, the main component of the plasma-derived SiO2-NPs' hard corona, has antiopsonin characteristics and uniquely confers to these particles the ability to evade macrophage capture.
authors.affiliation: Centro di Ricerca Interdipartimentale per le Biotecnologie Innovative, Università di Padova, via U. Bassi 58/B, I-35131, Padova, Italy. emanuele.papini@unipd.it and Dipartimento di Scienze Biomediche, Università di Padova, via U. Bassi 58/B, I-35131, Padova, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Fedeli
authors.affiliation: Dipartimento di Biologia, Università di Padova, via U. Bassi 58/B, I-35131, Padova, Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: Segat
authors.affiliation: Centro di Ricerca Interdipartimentale per le Biotecnologie Innovative, Università di Padova, via U. Bassi 58/B, I-35131, Padova, Italy. emanuele.papini@unipd.it and Dipartimento di Scienze Biomediche, Università di Padova, via U. Bassi 58/B, I-35131, Padova, Italy.
authors.forename: Regina
authors.initials: R
authors.lastname: Tavano
authors.affiliation: Dipartimento di Biologia, Università di Padova, via U. Bassi 58/B, I-35131, Padova, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Bubacco
authors.affiliation: Centro di Ricerca Interdipartimentale per le Biotecnologie Innovative, Università di Padova, via U. Bassi 58/B, I-35131, Padova, Italy. emanuele.papini@unipd.it.
authors.forename: Giorgia
authors.initials: G
authors.lastname: De Franceschi
authors.affiliation: Centro di Ricerca Interdipartimentale per le Biotecnologie Innovative, Università di Padova, via U. Bassi 58/B, I-35131, Padova, Italy. emanuele.papini@unipd.it.
authors.forename: Patrizia Polverino
authors.initials: PP
authors.lastname: de Laureto
authors.affiliation: Dipartimento di Scienze Chimiche, Università di Padova, via Marzolo 1, I -35131, Padova, Italy. fabrizio.mancin@unipd.it.
authors.forename: Elisa
authors.initials: E
authors.lastname: Lubian
authors.affiliation: Dipartimento di Scienze Chimiche, Università di Padova, via Marzolo 1, I -35131, Padova, Italy. fabrizio.mancin@unipd.it.
authors.forename: Francesco
authors.initials: F
authors.lastname: Selvestrel
authors.affiliation: Dipartimento di Scienze Chimiche, Università di Padova, via Marzolo 1, I -35131, Padova, Italy. fabrizio.mancin@unipd.it.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Mancin
authors.affiliation: Centro di Ricerca Interdipartimentale per le Biotecnologie Innovative, Università di Padova, via U. Bassi 58/B, I-35131, Padova, Italy. emanuele.papini@unipd.it and Dipartimento di Scienze Biomediche, Università di Padova, via U. Bassi 58/B, I-35131, Padova, Italy.
authors.forename: Emanuele
authors.initials: E
authors.lastname: Papini
mesh_terms: D000818:Animals; D001798:Blood Proteins / Q000737:chemistry / Q000378:metabolism; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D016650:Fluorescein-5-isothiocyanate / Q000737:chemistry; D006801:Humans; D007704:Kininogens / Q000737:chemistry / Q000378:metabolism; D008264:Macrophages / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D053758:Nanoparticles / Q000737:chemistry*; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism; D012822:Silicon Dioxide / Q000737:chemistry*; D053719:Tandem Mass Spectrometry; D000099053:Histidine-Rich Glycoprotein
chemical_list: D001798:Blood Proteins; D007704:Kininogens; D011506:Proteins; D000099053:Histidine-Rich Glycoprotein; D012822:Silicon Dioxide; D016650:Fluorescein-5-isothiocyanate