The link between Alzheimer’s and mad cow disease

Could there be a link between Alzheimer’s disease and mad cow disease? Most likely, according to researchers at Yale University. And the link seems to be in the proteins called prions that are associated with mad cow disease (bovine spongiform encephalopathy or BSE in medical speak) and its human equivalent Creutzfeldt-Jakob disease. BSE is a neurodegenerative disease in cattle that has caused fatalities in Europe, especially in the UK. Furthermore, it is feared that those who consume the brain of the infected animals may also develop the disease in the form of Creutzfeldt-Jakob disease (CJD).

Alzheimer’s disease (AD) is characterized by amyloid aggregrates or plaques that accumulate in the brain. These aggregates are formed by a misfolded protein β-amyloid (Aβ)

However, the mechanism with which Aβ triggers neuron damage and death in AD patients has always been a mystery.

According to Stephen Strittmatter, professor of neurology at Yale School of Medicine and lead study researcher

“The mechanism by which the production of Aβ makes neurons sick has been a black box. In this study we set out to understand how a certain form of Aβ associated with disease, the oligomeric form, can interact with neurons and trigger the toxic cascade of the disease process. We identified PrP [prion protein] as the surface protein needed for Aβ to disrupt functions of neurons in a dish.”

The prion protein (PrP) is the protein that forms aggregates in mad cow disease and CJD. The Yale researchers have also identified it to be one of the main cellular receptors for Aβ. The study findings suggest that these two proteins PrP and Aβ activate a neurodegenerative disease signaling pathway that is common to both AD and CJD. The results have been published in the journal Nature. Many researchers in the field of neurodegenerative disorders are surprised by the findings because PrP has never been linked to memory function and dysfunction before.

The Yale researchers made their observations on the behavior of the said proteins in vitro, e.g. in cell cultures in the lab. The study has opened new avenues in AD research. The next step would be to check whether the Aβ-PrP link has any functional significance in vivo. It is expected that more studies will now focus on the exploring this protein connections in animal models.

In addition, the study findings also suggest the possibility of a new therapeutic angle for AD. Monoclonal antibodies (mAbs) that target PrP, for example, could potentially be useful in treating AD. PrP antibodies which have been developed by veterinary diagnostics companies for animal use may also be explored for potential therapeutic use in the treatment of AD.