HEAT-Net 2021 | A novel method for detection of early oligomeric α-synuclein pathology

The ASO-PLA, the proximity ligation assay for targeting alpha-synuclein oligomers has been published in a group from UK in 2015. And actually PLA as a technology was developed in Uppsala, where I work on the third floor here. So I was familiar with the technique and then we saw this paper and we thought that we might use it to target oligomers, to visualize oligomers, as it has been very challenging using immunohistochemistry. And if you read a recent paper from Hilal Lashuel’s group, they talked about that all the claimed alpha-synuclein antibodies do not recognize what they claim to be. There are no antibodies which are perfect.

So, then PLA doesn’t rely on only one antibody, but it’s a combination of two antibodies, and that’s the advantage of it. And our paper, which we published recently on mouse data, on A30P alpha-synuclein in mouse model, we could see that you can monitor the oligomeric pathology in the mouse and build up of these alpha-synuclein oligomers in the mid-brain neurons. This mouse model has been established something like 20 years ago. And the thing with a lot of groups, different groups have characterized pathology in this mouse model using immunohistochemistry. And in early 2010s there was technique of protein scale PET blot, which enabled us to detect aggregated species, but since all these previous papers reported the pathology at quite later stage.

When our group in 2013 published a paper using oligomer confirmation specific antibody in these mice we could see some signal as early as four months of age. So, we were not sure if it is indeed detecting oligomers, so we kind of continued on those lines, using the sensitive technique. And then we could see start of oligomerization process already at two months in this mouse, which has not been reported before. So, we improved the detection of earlier aggregate species using this technique, so we think that we could do similar stuff with using human postmortem material.

As an extension or a follow-up study, we are doing it in humans, but using different antibodies. And the idea behind this project is to visualize if we can differentiate between aggregates and its properties in different synucleinopathies. This study is not published yet, and it’s still in preliminary stage. What we did in the preliminary data was we had n=3 in Parkinson’s disease dementia, dementia with Lewy body, and Parkinson’s disease cases, and also neurologically normal controls.

And on these postmortem brain material we coupled different alpha-synuclein antibodies from N-terminus to C-terminus while keeping the phosphorylated synuclein antibody common. And our initial results indicate that with certain antibody pairing, you can differentiate between the different aggregation species in different synucleinopathies, but since this is at very early stage I cannot say anything for sure, but we are planning to add more cases and do those, then we can perform statistics and say something for concrete.