A neuron protein may trigger Alzheimer’s early

The research, published in Nature, focused on ERBB4, a receptor found on the surface of active neurons. Under normal conditions, this protein assists communication between nerve cells. In Alzheimer’s mouse models, however, ERBB4 appeared far too early and at far too high levels. It was concentrated in a specific group of cells the researchers called ‘early-responsive excitatory neurons.’

When the team selectively deleted the ERBB4 gene in those cells, multiple Alzheimer hallmarks retreated simultaneously: abnormal neuronal network activity, synapse loss, reactive gliosis, amyloid plaque deposition, and cognitive deficits all decreased. Conversely, artificially overexpressing ERBB4 in healthy mice reproduced these same features, even without amyloid plaques. That finding is notable, given that Alzheimer research has long focused almost exclusively on amyloid.

mTOR as the link

The protein acts through mTOR, a well-known cellular growth pathway that regulates how cells grow, divide, and respond to stress. Overactive ERBB4 appears to switch mTOR on, which then propagates downstream damage. Analyses of human Alzheimer brain tissue showed that elevated ERBB4 activity correlated with tau protein spread and cognitive decline, partially supporting the mouse findings.

Reasons for caution

Caution remains warranted. Alzheimer mouse models are artificial constructs: mice do not naturally develop the disease, and the models embed assumptions about which mechanisms matter. Findings in mice often do not translate to humans. The human data are promising but not conclusive. From a longevity perspective, the discovery is intriguing: if ERBB4 overexpression is indeed an early event, intervening on this protein or on mTOR could potentially slow disease progression before visible damage occurs. What that would look like clinically remains unknown.

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