Although Alzheimer’s disease is commonly known as a condition that affects the brain, new research reveals that its impact extends to other organs throughout the body. In a groundbreaking study, scientists from Baylor College of Medicine, the Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, and their partners, used fruit flies to explore the wider effects of Alzheimer’s disease at the cellular level.

Published in Neuron, the study introduces the Alzheimer’s Disease Fly Cell Atlas, a detailed map of gene expression across 219 different cell types found in both the heads and bodies of genetically modified fruit flies. These flies were engineered to produce either the Aβ42 or Tau proteins—two major culprits in Alzheimer’s disease, specifically in their neurons, thereby simulating the disease without affecting development.

“We observed that expressing Aβ42 or Tau in neurons led to significant changes not only in the nervous system but also in other body tissues,” explained Ye-Jin Park, co-first author and graduate student. Notably, Aβ42 caused marked damage to sensory neurons involved in smell, hearing, and vision, with specific damage to olfactory neurons, aligning with clinical signs of early Alzheimer’s.

In contrast, Tau protein expression produced widespread disruptions in peripheral organs, including altered fat metabolism, digestive issues, and reduced fertility. According to Dr. Tzu-Chiao Lu, co-first author and postdoctoral researcher, these effects closely resemble signs of accelerated aging and point to disrupted brain-body communication.

“This comprehensive cell atlas gives us a new perspective on how Alzheimer ’s-associated proteins influence the body beyond the brain,” said Dr. Hugo Bellen, co-corresponding author and chair in neurogenetics at Duncan NRI. “It opens new doors to discovering biomarkers and developing therapies that target Alzheimer’s from a whole-body approach”.
The resource is expected to aid researchers worldwide in studying the systemic effects of neurodegeneration, furthering understanding and potentially improving treatment options for patients.