Brain organoid model shows molecular signs of Alzheimer’s before birth

In a model of human fetal brain development, Emory researchers can see perturbations of epigenetic markers in cells derived from people with familial early-onset Alzheimer’s disease, which takes decades to appear. This suggests that in people who inherit mutations linked to early-onset Alzheimer’s, it would be possible to detect molecular changes in their brains before birth. The results were published in the journal Cell Reports. “The beauty of using organoids is that they allow us to Read more

The earliest spot for Alzheimer's blues

How the most common genetic risk factor in AD interacts with the earliest site of neurodegeneration Read more

Make ‘em fight: redirecting neutrophils in CF

Why do people with cystic fibrosis (CF) have such trouble with lung infections? The conventional view is that people with CF are at greater risk for lung infections because thick, sticky mucus builds up in their lungs, allowing bacteria to thrive. CF is caused by a mutation that affects the composition of the mucus. Rabindra Tirouvanziam, an immunologist at Emory, says a better question is: what type of cell is supposed to be fighting the Read more

Joubert syndrome

Hedgehog pathway outside cilia

Emory geneticist Tamara Caspary is an expert on the Hedgehog pathway, critical for brain development. In particular, she and her colleagues have been studying a gene that is part of the Hedgehog pathway called Arl13b, which is mutated in Joubert syndrome, affecting development of the cerebellum and brain stem.

The Arl13b protein was known to be enriched in primary cilia, tiny hair-like cellular structures with a signaling/navigation function in neuronal development. However Caspary’s lab, in a collaboration with Frederic Charron’s group in Montreal, has found that Arl13b can also function outside cilia: in axons and growth cones.

The Hedgehog pathway has several roles, some in specifying what embryonic cells will become, and others in terms of guiding growing axons, the scientists conclude in their new paper in Cell Reports.

“Arl13b regulates Shh [Sonic Hedgehog] signaling through two mechanisms: a cilia-associated one to specify cell fate and a cilia localization-independent one to guide axons,” they write.  A related preprint, confirming Arl13b’s extra-ciliary role in mouse development, has been posted on bioRxiv.

 

 

 

 

 

Posted on by Quinn Eastman in Neuro Leave a comment