Scientists may have uncovered a key mechanism involved in the brain degeneration seen in conditions such as Parkinson's and Alzheimer's disease.
Several neurological disorders are marked by proteins that aggregate, or accumulate in the brain. Normal proteins may become insoluble and clump together when they sporadically "misfold" and change shape. One protein, called tau, clumps into the twisted threads known as tangles that are a hallmark of Alzheimer's disease. Alpha-synuclein clumps to form the Lewy bodies associated with Parkinson's disease.
Different types of protein clumps often appear in the same patients. For example, more than half of Alzheimer's dsiease patients also have Lewy bodies in their brains. The mechanism that underlies widespread protein misfolding isn't well understood. One potential explanation is that the protein maintenance machinery has gone awry in disease brains. Studies have also found that certain misfolded "seed" proteins can induce shape changes in other proteins they contact.
Alpha-synuclein and tau proteins can promote each other's aggregation under certain conditions in the lab. Recently, a research team showed that synthetic alphs-synuclein fibrils can induce tau aggregation in non-neuronal cells. In their new study - led by Drs. Jing L. Guo and Virginia M.Y. Lee from the University of Pennsylvania - explored these effects in neurons and mice.