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.
-end-


American Association for the Advancement of Science

Related Infection Articles:

Sensing infection, suppressing regeneration
UIC researchers describe an enzyme that blocks the ability of blood vessel cells to self-heal.
Boost to lung immunity following infection
The strength of the immune system in response to respiratory infections is constantly changing, depending on the history of previous, unrelated infections, according to new research from the Crick.
Is infection after surgery associated with increased long-term risk of infection, death?
Whether experiencing an infection within the first 30 days after surgery is associated with an increased risk of another infection and death within one year was the focus of this observational study that included about 660,000 veterans who underwent major surgery.
Revealed: How E. coli knows how to cause the worst possible infection
The discovery could one day let doctors prevent the infection by allowing E. coli to pass harmlessly through the body.
UK study shows most patients with suspected urinary tract infection and treated with antibiotics actually lack evidence of this infection
New research presented at this week's European Congress of Clinical Microbiology & Infectious Diseases (ECCMID) in Amsterdam, Netherlands (April 13-16, 2019) shows that only one third of patients that enter the emergency department with suspected urinary tract infection (UTI) actually have evidence of this infection, yet almost all are treated with antibiotics, unnecessarily driving the emergence of antimicrobial resistance.
Bacteria in urine doesn't always indicate infection
Doctors should think carefully before testing patients for a urinary tract infection (UTI) to avoid over-diagnosis and unnecessary antibiotic treatment, according to updated asymptomatic bacteriuria (ASB) guidelines released by the Infectious Diseases Society of America (IDSA) and published in Clinical Infectious Diseases.
Subsidies for infection control to healthcare institutions help reduce infection levels
Researchers compared three types of infection control subsidies and found that under a limited budget, a dollar-for-dollar matching subsidy, in which policymakers match hospital spending for infection control measures, was the most effective at reducing the number of hospital-acquired infections.
Dengue virus infection may cause severe outcomes following Zika virus infection during pregnancy
This study is the first to report a possible mechanism for the enhancement of Zika virus progression during pregnancy in an animal model.
How common is Hepatitis C infection in each US state?
Hepatitis C virus infection is a major cause of illness and death in the United States and injection drug use is likely fueling many new cases.
The medicine of the future against infection and inflammation?
Researchers at Lund University in Sweden, have in collaboration with colleagues in Copenhagen and Singapore, mapped how the body's own peptides act to reduce infection and inflammation by deactivating the toxic substances formed in the process.
More Infection News and Infection Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Meditations on Loneliness
Original broadcast date: April 24, 2020. We're a social species now living in isolation. But loneliness was a problem well before this era of social distancing. This hour, TED speakers explore how we can live and make peace with loneliness. Guests on the show include author and illustrator Jonny Sun, psychologist Susan Pinker, architect Grace Kim, and writer Suleika Jaouad.
Now Playing: Science for the People

#565 The Great Wide Indoors
We're all spending a bit more time indoors this summer than we probably figured. But did you ever stop to think about why the places we live and work as designed the way they are? And how they could be designed better? We're talking with Emily Anthes about her new book "The Great Indoors: The Surprising Science of how Buildings Shape our Behavior, Health and Happiness".
Now Playing: Radiolab

The Third. A TED Talk.
Jad gives a TED talk about his life as a journalist and how Radiolab has evolved over the years. Here's how TED described it:How do you end a story? Host of Radiolab Jad Abumrad tells how his search for an answer led him home to the mountains of Tennessee, where he met an unexpected teacher: Dolly Parton.Jad Nicholas Abumrad is a Lebanese-American radio host, composer and producer. He is the founder of the syndicated public radio program Radiolab, which is broadcast on over 600 radio stations nationwide and is downloaded more than 120 million times a year as a podcast. He also created More Perfect, a podcast that tells the stories behind the Supreme Court's most famous decisions. And most recently, Dolly Parton's America, a nine-episode podcast exploring the life and times of the iconic country music star. Abumrad has received three Peabody Awards and was named a MacArthur Fellow in 2011.