Connect with us

BIOLOGY

Study identifies molecule that allows bacteria to breach cellular barriers

Charles Roper

Published

on

A new study identifies a single molecule as a key entry point used by two types of dangerous bacteria to break through cellular barriers and cause disease. The findings, published March 19 in the journal mBio, suggest that blocking the interaction between the molecule, known as CD40, and bacteria may represent a universal strategy for preventing life-threatening illnesses, including toxic shock syndrome.

The two bacteria, Staphylococcus aureus (staph) and Streptococcus pyogenes, cause many serious illnesses. According to the Centers for Disease Control and Prevention, staph causes 70,000 cases of highly fatal pneumonia, 40,000 cases of severe heart infections, and over 500,000 post-surgical infections each year. Streptococcus pyogenes causes 10 million cases of sore throat and 30,000 cases of severe invasive diseases annually.

“Many of the infections caused by these two bacteria start on the skin or on the mucosal surfaces that line body cavities like the nose, mouth and throat, the gut, and the vagina. The ability of these bacteria to cause disease depends on production of a family of toxins known as superantigens, which cause exceptionally harmful inflammation,” explains Patrick Schlievert, Ph.D., professor and head of microbiology and immunology at the University of Iowa Carver College of Medicine and lead author of the new study.

Previous work by Schlievert showed that superantigens cause the epithelial cells of the mucosal barrier to make signaling molecules called chemokines. Those chemokines attract immune cells that disrupt the integrity of the mucosal barrier, allowing the superantigens and frequently the bacteria themselves to penetrate and cause serious and often fatal diseases, including toxic shock syndrome.

In the new study, Schlievert and his colleagues at the UI and National Jewish Health in Denver used human vaginal epithelial cells as a model of a mucosal barrier. They showed that the interaction between CD40 and superantigens triggers the production of chemokines in these cells. Removing CD40 from the cells using CRISPR gene editing prevented bacterial superantigens from triggering the production of the chemokines. In contrast, restoring CD40 to those cells restored the ability of superantigens to trigger chemokine production.

The team tested three superantigens: toxic shock syndrome toxin 1 (TSST-1), and staphylococcal enterotoxin B and C. Of the three, TSST-1 produced the strongest effect, which likely explains why this superantigen is responsible for all cases of menstrual toxic shock syndrome.

“CD40 is critical; you get no response (to the superantigens) without it,” Schlievert says. “Since we now know that these two large families of bacteria cause disease through the same human tissue receptor, we are looking for ways to block the interaction between CD40 and superantigens to prevent immune activation. This work also raises the possibility that many other pathogens may cause diseases through the same receptor interaction. Those studies are underway.

“If there is a central pathway that many pathogens use to disrupt mucosal barriers, that would mean we have a single target to block to prevent barrier disruption by pathogens. That could be huge,” he adds.


Explore further:
Bacteria may cause type 2 diabetes

More information:
Patrick M. Schlievert et al, Staphylococcal Superantigens Stimulate Epithelial Cells through CD40 To Produce Chemokines, mBio (2019). DOI: 10.1128/mBio.00214-19

Journal reference:
mBio

Provided by:
University of Iowa

Co-host on the H.P.S.N. talk show and co-founder of the Human Parasites Support Network. Content contributor, survivor and victim of a parasitic infection. #Computer guy. #WebDeveloper #Marketer #Entrepreneur #BusinessOwner #UniversityofOklahoma

Continue Reading
Click to comment

Leave a Reply

Your email address will not be published. Required fields are marked *

Medical News

#CDC

@RS1Photo Retailers have been advised not to sell romaine grown in Salinas. Many romaine companies have offices in Salinas. Harvest region labels are different than the information showing company name and address. Read more on how to identify affected lettuce: go.usa.gov/xpngY

@WickedHotNails @CDCemergency Retailers have been advised not to sell romaine grown in Salinas. Many romaine companies have offices in Salinas. Harvest region labels are different than the information showing company name and address. Read more on how to identify affected lettuce: go.usa.gov/xpngY

@CDCMMWR #Clinicians: New @CDCMMWR shows e-cigarette, or vaping, product use–associated lung injury (EVALI) patients continue to be mostly young adults, white men, & that 80% report use of THC-containing product brands. bit.ly/MMWREVALI

test Twitter Media - @CDCMMWR #Clinicians: New @CDCMMWR shows e-cigarette, or vaping, product use–associated lung injury (EVALI) patients continue to be mostly young adults, white men, & that 80% report use of THC-containing product brands. https://t.co/RR5aQn3tO6 https://t.co/E6H1UM7bBS

@babygirllucy6 @harvest_joy Iceberg grown in Salinas is not included in CDC’s warning about the current outbreak. The CDC warning applies only to romaine lettuce grown in the Salinas region. Outbreak updates will be posted here: go.usa.gov/xpXg8.

#LymeDisease

NY lab found that 32% of ticks carry diseases. Lyme was found in 26%. “We didn’t expect in the fall for the numbers to be that high,” Thangamani said. #LymeDisease syracuse.com/news/2019/12/a…

"There are no words to explain how I feel about the five years that have slipped away from me." #LymeDisease yahoo.com/lifestyle/refl…

Thank you @bldwn_co & Dori! If you’re in LA tomorrow, shop & join our fight against #LymeDisease #GivingTuesday twitter.com/avrilfoundatio…

#NTD’s

No result could be fetched.

Trending

Copyright © 2019. All Rights Reserved. The Human Parasite Support Network.