A study of 48 post-mortem brains found a protein that appears to protect brain cells from Alzheimer’s — even in people who had significant amounts of amyloid plaques in their brains.
ARI SHAPIRO, HOST:
Now a new insight into how the brain may protect itself against one risk of aging. There’s evidence that a protein produced naturally by some brain cells may ward off Alzheimer’s disease. NPR’s Jon Hamilton reports on a study of postmortem brains, which seems to confirm the importance of a molecule that has intrigued some researchers for decades.
JON HAMILTON, BYLINE: The protein is called reelin. It became a scientific celebrity last year, thanks to a Colombian man who should have developed Alzheimer’s in middle age but didn’t. The man was part of a large family in the area around Medellin that carries a very rare gene variant. Dr. Joseph Arboleda-Velasquez of Harvard Medical School says family members who inherit the gene are virtually certain to develop Alzheimer’s.
JOSEPH ARBOLEDA-VELASQUEZ: So they start with cognitive decline in their 40s. Then it develops into full-blown dementia – late 40s or early 50s.
HAMILTON: But this man was in his late 60s and still fine. After he died, scientists found that the man’s brain was riddled with amyloid plaques, a hallmark of Alzheimer’s. They also found another sign of Alzheimer’s, tangled fibers called tau. But Arboleda-Velasquez says, oddly, these tangles were mostly absent in a brain region called the entorhinal cortex.
ARBOLEDA-VELASQUEZ: And that region of the brain seems to be very important because it’s a region where Alzheimer’s kind of begins, like, a lot of the pathology starts there.
HAMILTON: The researchers studied the man’s genome, and they found something that might explain why his brain had been protected. He carried a rare variant of the gene that makes the protein reelin.
LI-HUEI TSAI: So people started to get excited about reelin.
HAMILTON: That’s Li-Huei Tsai, a professor at MIT who directs The Picower Institute for Memory and Learning. She and a team had already been studying reelin’s role in Alzheimer’s. They decided to look at postmortem brains from 48 people. About half had shown symptoms of Alzheimer’s. The rest appeared to have normal thinking and memory when they died. But Tsai says a few of these apparently unaffected people had brains that were full of amyloid plaques.
TSAI: We want to know what’s so special about those individuals.
HAMILTON: The team did a genetic analysis of the neurons in six different brain regions. They found several differences, including a surprising one in the entorhinal cortex – the same area that was protected in the man from Colombia.
TSAI: And we couldn’t believe that the neurons that are most vulnerable to Alzheimer’s neurodegeneration – they share one feature, which is they highly express reelin.
HAMILTON: In other words, Alzheimer’s appears to kill off the neurons that make reelin, the protein thought to help protect the brain from the disease. And the finding fits well with what scientists learned about the Colombian man whose brain had defied Alzheimer’s. He had carried a variant of the reelin gene that seemed to make the protein more potent. Perhaps that offset any reelin deficiency caused by Alzheimer’s. Tsai says she and her team are now using artificial intelligence to help find a drug that can replicate what reelin does naturally.
TSAI: So we think that we’re onto something very important for Alzheimer disease.
HAMILTON: Arboleda-Velasquez from Harvard says the study, which appears in the journal Nature, is likely to have a big impact.
ARBOLEDA-VELASQUEZ: It confirms the importance of reelin, which I have to say had been overlooked.
HAMILTON: Arboleda-Velasquez, who was born in Colombia, says the reelin story owes a lot to the people around Medellin whose lives have been devastated by a rare genetic variant.
ARBOLEDA-VELASQUEZ: These are just people that agreed to participate in research and get their blood drawn and then donate their brain after death. And they changed the world.
HAMILTON: Perhaps in a way that will eventually prevent early Alzheimer’s in their own offspring. Jon Hamilton, NPR News.
(SOUNDBITE OF VICTOR RAY SONG, “FALLING INTO PLACE”)
Copyright © 2024 NPR. All rights reserved. Visit our website terms of use and permissions pages at www.npr.org for further information.
NPR transcripts are created on a rush deadline by an NPR contractor. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.
Conclusion
The discovery of reelin and its potential role in protecting brain cells from Alzheimer’s disease is a significant breakthrough in the field of neuroscience. The study of post-mortem brains has shed light on how this protein could be a key player in preventing the onset of Alzheimer’s, even in individuals with high levels of amyloid plaques. Further research and development in this area could lead to groundbreaking treatments and therapies for Alzheimer’s patients in the future.
FAQs
Q: What is reelin?
Reelin is a protein naturally produced by some brain cells that has shown potential in protecting against Alzheimer’s disease.
Q: How was reelin discovered to be protective against Alzheimer’s?
A study of post-mortem brains, including that of a Colombian man with a rare gene variant, revealed that individuals with high levels of reelin in their brains showed protection against Alzheimer’s despite the presence of amyloid plaques.
Q: What are the implications of this discovery?
The discovery of reelin’s protective effects could lead to the development of new treatments and therapies for Alzheimer’s patients by replicating the protein’s actions through drug interventions.
