The illustration shows the key message of the study “Poly(ADP-ribose) drives pathologic alpha-synuclein neurodegeneration in Parkinson’s disease”. It was adopted and published in Science. Inhibition of PARP or deletion of PARP-1 reduces alpha-synuclein PFF-induced cell death. In a feed-forward loop, PAR causes the formation of a more toxic alpha-synuclein strain, resulting in accelerated pathologic alpha-synuclein transmission and toxicity. The article can be found here: https://science.sciencemag.org/content/362/6414/eaat8407.