Nav: Home

Can Alzheimer's disease-associated peptide fight bacterial infection?

May 25, 2016

Amyloid-ß is a sticky peptide notorious for forming destructive plaques in the brains of Alzheimer's disease patients, but a new study suggests that it may also serve a protective function as an antimicrobial peptide. Researchers show that fibrous nets of amyloid-ß can ensnare invading microbes, halting infection in mouse and worm models of Alzheimer's disease. The findings raise intriguing questions about whether an overactive immune response by amyloid-ß, either to a real or perceived microbial threat, can trigger disease. A better understanding of the peptide's role in the brain's immune system may open new therapeutic avenues for Alzheimer's disease, the researchers say. Amyloid-ß is widely viewed as an abnormal byproduct of cells, but whether the peptide, which is conserved across many species throughout evolution, has a normal function remains unclear. Recent research revealed that it exhibits strong antimicrobial activity to clinically relevant pathogens in vitro. Here, Deepak Kumar Vijaya Kumar and colleagues show that amyloid-ß can protect against bacterial and fungal infection in nematodes and mice in vivo. Mice that overexpressed the peptide showed greater resistance to bacterial infection, with improved survival compared to normal mice or mice unable to produce amyloid-ß. In mice with Alzheimer's disease, injecting Salmonella typhimurium into the brain stimulated and accelerated amyloid-ß to cluster around the bacteria. Amyloid-ß fibrils seemed to form nets that captured and entrapped bacterial cells to prevent infection, a mechanism similar to that used by known antimicrobial peptides. Altogether, the findings cast amyloid-ß in new light as a peptide with dual protective and damaging functions, prompting re-examination of the role of infection in Alzheimer's disease.

American Association for the Advancement of Science

Related Infection Articles:

Male infertility: Urogenital infection as a possible cause
In couples who have not been able to have children, male infertility is the cause in at least half of cases.
A novel approach to seeing dengue infection in the body
Positron emission tomography (PET) paired with the glucose metabolism probe, fluorodeoxyglucose (FDG), is considered 'old' technology in the field of cancer.
Smelling the risk of infection
Humans and monkeys are social beings and benefit from a community.
Tuberculosis and HIV co-infection
The HIV virus increases the potency of the tuberculosis bacterium (Mtb) by affecting a central function of the immune system.
New insight into course and transmission of Zika infection
In one of the first and largest studies of its kind, a research team lead by virologists at Beth Israel Deaconess Medical Center has characterized the progression of two strains of the viral infection.
More Infection News and Infection Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Teaching For Better Humans
More than test scores or good grades — what do kids need to prepare them for the future? This hour, guest host Manoush Zomorodi and TED speakers explore how to help children grow into better humans, in and out of the classroom. Guests include educators Olympia Della Flora and Liz Kleinrock, psychologist Thomas Curran, and writer Jacqueline Woodson.
Now Playing: Science for the People

#535 Superior
Apologies for the delay getting this week's episode out! A technical glitch slowed us down, but all is once again well. This week, we look at the often troubling intertwining of science and race: its long history, its ability to persist even during periods of disrepute, and the current forms it takes as it resurfaces, leveraging the internet and nationalism to buoy itself. We speak with Angela Saini, independent journalist and author of the new book "Superior: The Return of Race Science", about where race science went and how it's coming back.