Tau protein reverses energy flow in brain cells

Tau is already well known for forming harmful tangles inside neurons. But exactly how it triggers cell death has remained partly unclear. A team led by scientists at Stanford found that tau can latch onto the cell’s energy factories (mitochondria) and push electrons in the wrong direction through the energy-generating chain.

Normally, electrons flow in one direction through mitochondria, generating energy in the process. When tau reverses that flow, a process the researchers call reverse electron transport, it generates damaging oxygen molecules (reactive oxygen species), causes cellular stress, and triggers inflammation. The study showed that blocking this process reversed many of the harmful effects and improved learning and memory in flies and mice.

From animal models to human tissue

The animal findings are notable on their own. But the team also analysed human neurons grown in the laboratory and brain tissue from patients. Early evidence suggested that blocking the retrograde electron flow could make human neurons healthier as well. These are preliminary laboratory data; whether this translates into an effective treatment in people has not been tested.

Two of the study’s authors have founded a biotech company to pursue this idea further. That gives the hypothesis momentum, but also introduces commercial interests worth keeping in mind when interpreting future results.

A new angle on drug development

Tau is already an active target in pharmaceutical development, with several drugs attempting to prevent tangle formation. This finding adds a separate mechanism: tau may cause harm not only through tangles but also by disrupting mitochondrial energy flow. That opens a new avenue for drug design. For now, this remains a promising hypothesis, not a proven treatment.

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