Cellular Uptake of alpha-Synuclein Oligomer-Selective Antibodies is Enhanced by the Extracellular Presence of alpha-Synuclein and Mediated via Fc gamma Receptors

• Immunotherapy targeting aggregated alpha-synuclein has emerged as a potential treatment strategy against Parkinson's disease and other alpha-synucleinopathies. We have developed alpha-synuclein oligomer/protofibril selective antibodies that reduce toxic alpha-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 alpha-synuclein antibodies, linear epitope monoclonal alpha-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, alpha-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 alpha-synuclein displayed a higher uptake as compared to cells incubated with regular media. Finally, different Fc gamma receptors were targeted and we then found that blockage of Fc gamma RI and Fc gamma RIIB/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 alpha-synuclein and mediated via Fc gamma receptors. Altogether, our finding lend further support to the belief that alpha-synuclein pathology can be modified by monoclonal antibodies and that these can target toxic alpha-synuclein species in the extracellular milieu. In the context of immunotherapy, antibody binding of alpha-synuclein would then not only block further aggregation but also mediate internalization and subsequent degradation of antigen-antibody complexes.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Geriatrik (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Geriatrics (hsv//eng)

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Cell- och molekylärbiologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Cell and Molecular Biology (hsv//eng)

Nyckelord

alpha-Synuclein

Parkinson's disease

Lewy bodies

Monoclonal antibodies

Antibody uptake

Fc gamma receptors

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