title: Cellular Uptake of α-Synuclein Oligomer-Selective Antibodies is Enhanced by the Extracellular Presence of α-Synuclein and Mediated via Fcγ Receptors.
abstract: Immunotherapy targeting aggregated α-synuclein has emerged as a potential treatment strategy against Parkinson's disease and other α-synucleinopathies. We have developed α-synuclein oligomer/protofibril selective antibodies that reduce toxic α-synuclein in a human cell line and, upon intraperitoneal administration, in spinal cord of transgenic mice. Here, we investigated under which conditions and by which mechanisms such antibodies can be internalized by cells. For this purpose, human neuroglioma H4 cells were treated with either monoclonal oligomer/protofibril selective α-synuclein antibodies, linear epitope monoclonal α-synuclein antibodies, or with a control antibody. The oligomer/protofibril selective antibody mAb47 displayed the highest cellular uptake and was therefore chosen for additional analyses. Next, α-synuclein overexpressing cells were incubated with mAb47, which resulted in increased antibody internalization as compared to non-transfected cells. Similarly, regular cells exposed to mAb47 together with media containing α-synuclein displayed a higher uptake as compared to cells incubated with regular media. Finally, different Fcγ receptors were targeted and we then found that blockage of FcγRI and FcγRIIB/C resulted in reduced antibody internalization. Our data thus indicate that the robust uptake of the oligomer/protofibril selective antibody mAb47 by human CNS-derived cells is enhanced by extracellular α-synuclein and mediated via Fcγ receptors. Altogether, our finding lend further support to the belief that α-synuclein pathology can be modified by monoclonal antibodies and that these can target toxic α-synuclein species in the extracellular milieu. In the context of immunotherapy, antibody binding of α-synuclein would then not only block further aggregation but also mediate internalization and subsequent degradation of antigen-antibody complexes.
authors.affiliation: Department of Public Health/Molecular Geriatrics, Uppsala University, Uppsala, Sweden.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Gustafsson
authors.affiliation: BioArctic Neuroscience AB, Stockholm, Sweden.
authors.forename: Fredrik
authors.initials: F
authors.lastname: Eriksson
authors.affiliation: BioArctic Neuroscience AB, Stockholm, Sweden.
authors.forename: Christer
authors.initials: C
authors.lastname: Möller
authors.affiliation: Department of Neurodegeneration and Restorative Research, University Medical Center Göttingen, Göttingen, Germany.
authors.forename: Tomás Lopes
authors.initials: TL
authors.lastname: da Fonseca
authors.affiliation: Department of Neurodegeneration and Restorative Research, University Medical Center Göttingen, Göttingen, Germany.|Max Plank Institute for Experimental Medicine, Göttingen, Germany.
authors.forename: Tiago F
authors.initials: TF
authors.lastname: Outeiro
authors.affiliation: Department of Public Health/Molecular Geriatrics, Uppsala University, Uppsala, Sweden.
authors.forename: Lars
authors.initials: L
authors.lastname: Lannfelt
authors.affiliation: Department of Public Health/Molecular Geriatrics, Uppsala University, Uppsala, Sweden.
authors.forename: Joakim
authors.initials: J
authors.lastname: Bergström
authors.affiliation: Department of Public Health/Molecular Geriatrics, Uppsala University, Uppsala, Sweden. martin.ingelsson@pubcare.uu.se.
authors.forename: Martin
authors.initials: M
authors.lastname: Ingelsson
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism*; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D005110:Extracellular Space / Q000378:metabolism*; D006801:Humans; D051379:Mice; D008822:Mice, Transgenic; D017452:Receptors, IgG / Q000502:physiology*; D051844:alpha-Synuclein / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D017452:Receptors, IgG; D051844:alpha-Synuclein
keywords: Antibody uptake; Fc gamma receptors; Lewy bodies; Monoclonal antibodies; Parkinson’s disease; α-Synuclein