A protein from the bacterium Helicobacter pylori has been shown to block the formation of harmful protein aggregates - known as amyloids - that are linked to Alzheimer's, Parkinson's and type 2 diabetes, among other diseases, and bacterial infections. This is the result of a new study published in the journal Science Advances.
Scientists have long known that misfolded proteins can form clumps in the body and contribute to several serious diseases. Now a new study shows that a protein from a bacterium commonly associated with stomach ulcers, Helicobacter pylori, can counteract this process.
Powerful amyloid inhibitor
The protein, called CagA, acts as a powerful inhibitor of amyloids - both in humans and in bacteria. In laboratory experiments, the researchers were able to show that CagA effectively blocks the formation of amyloid fibres from several disease-related proteins, including amyloid-beta, tau and alpha-synuclein, which are central to Alzheimer's and Parkinson's diseases.
"It is surprising that a bacterial protein can have such a broad effect on amyloids," says corresponding author Gefei Chen , Principal Researcher at the Department of Medicine, Huddinge .
"Our results show an unexpected link between bacterial infections and protection against certain protein-related diseases."
The study also shows that CagA affects bacteria's own amyloids, which are used to build biofilms - protective structures that make bacteria more resilient. When the researchers treated bacteria with CagA, both the density and stability of the biofilms decreased.
Possible path to new treatments
To understand how CagA works, the researchers used a combination of advanced techniques, including fluorescence measurements, electron microscopy and nuclear magnetic resonance (NMR). The results show that CagA can slow down amyloid formation even at very low concentrations.
The next step in the research is to find out exactly how CagA interacts with different proteins, and whether it can be used as the basis for new treatments for both bacterial infections and neurodegenerative diseases.
"We hope that our findings can pave the way for new strategies to tackle amyloid diseases," says Gefei Chen.
The study is the result of an extensive collaboration between researchers from several institutions, including Daniel Otzen from Aarhus University in Denmark, and Michael Landreh from Uppsala University.
Gefei Chen is supported by funding from the Alzheimer's Association (USA), Åke Wibergs Foundation and the Alzheimer Foundation.
Publication
Helicobacter pylori CagA protein is a potent and broad-spectrum amyloid inhibitor. Jin Z, Olsen WP, Mörman C, Leppert A, Kumar R, Møllebjerg A, Nielsen LG, Moshynets OV, Frasinyuk MS, Elosua JY, Ferreira D, Abelein A, Landreh M, Knight SD, Johansson J, Otzen DE, Chen G. Sci Adv. Online 11 June 2025, doi: 10.1126/sciadv.ads7525.
