You might be interested in the video from the Univ. of California - they are talking of a breakthrough - transforming Astrocytes into new Neurons and reversing PD (in mice for now)
Creating New Neurons: The Potential to Reverse Parkinson’s Disease
(Hear directly from the team that developed the groundbreaking ability to make new, healthy neurons that can replace those lost in Parkinson’s disease and their vision to turn their discovery into a life-changing therapy)