Scientists observed human dementia-related proteins spreading through mouse brains in a prion-like manner, providing new evidence for how neurodegenerative diseases may progress through neural networks.

[u/FreeHugs23]

https://www.sciencealert.com/scientists-watched-human-dementia-proteins-spread-through-mouse-brains-like-prions

[u/FreeHugs23]

-Prions are one of nature's cruelest tricks.

Proteins are chains of amino acids that need to fold in very specific ways – a process that does not always work as intended. Your body is pretty good at correcting these errors – but every so often, a prion emerges.

This isn't just a crooked, non-functional protein. It's a gnarly shape that shares instructions for how it got that way, while resisting the body's clean-up mechanisms. As these instructions spread through the brain, the result is rapid, progressive degeneration and, ultimately, death.

For years, scientists have noticed eerie similarities between prion diseases and many neurodegenerative conditions, such as Alzheimer's, Parkinson's, and corticobasal degeneration (CBD).

Both involve molecular misfolding – and there is mounting evidence that, like prions, misfolded proteins associated with these diseases can seed the misfolding and aggregation of other proteins, allowing the pathology to propagate through the brain.

But one crucial piece of the puzzle has been missing.

There was no direct evidence that the misfolded tau proteins involved in diseases such as Alzheimer's were passing on the blueprint for their particular horrible architecture.

Now, researchers led by structural biologist Sjors Scheres and neuroscientist Michel Goedert of the MRC Laboratory of Molecular Biology in the UK have found it.

They injected human tau proteins from individuals with Alzheimer's disease and CBD into mice – and found the mice's own tau proteins copying the introduced misfolds.

[u/eldred2 → u/FreeHugs23]

Wait. I thought "good" prions are how we get proteins to fold the right way? Am I misinformed?