Additionally, this was the followup paper that found Lewy bodies developing in the transplanted cells (suggesting some sort of spread/prion-like hypothesis with regards to Lewy bodies/insoluble alpha synuclein)

https://pubmed.ncbi.nlm.nih.gov/18391962/

edit: competing group also managed to publish theirs at the same time

https://pubmed.ncbi.nlm.nih.gov/18391963/