Navigation Links
Gatekeepers: Penn study discovers how microbes make it past tight spaces between cells
Date:6/16/2011

PHILADELPHIA - There are ten microbial cells for every one human cell in the body, and microbiology dogma holds that there is a tight barrier protecting the inside of the body from outside invaders, in this case bacteria. Bacterial pathogens can break this barrier to cause infection and senior author Jeffrey Weiser, MD, professor of Microbiology and Pediatrics from the Perelman School of Medicine at the University of Pennsylvania, and first author Thomas Clarke, PhD, a postdoctoral fellow in the Weiser lab, wondered how microbes get inside the host and circulate in the first place. Weiser and Clarke tested to see if microbes somehow weaken host cell defenses to enter tissues.

In this Cell Host & Microbe study, the investigators found that microbes open and get through the initial cellular barrier -- epithelial cells that line the airway -- in a programmed and efficient way. They surmise this could be a normal physiological event and the epithelial lining may not be as effective at keeping microbes out as once thought. Microbes that survive once past the epithelial lining tend to be pathogenic, such as Streptococcus pneumoniae and Haemophilus influenzae, two major human pathogens causing invasive infections. Their data support a general mechanism for epithelial opening exploited by invasive pathogens to facilitate movement into tissue to initiate disease.

Using microarray and PCR analysis of the epithelial cells' response to invasion by S. pneumoniae and H. influenzae, the researchers found a downregulation of genes called claudins that encode proteins key to keeping the spaces between epithelial cells tight. All animals recognize molecules in microbial cell walls. It was detection of these microbial molecules by host molecules called Toll-like receptors that caused the proteins responsible for keeping the cellular barrier tight to fall down on the job.

When modeled in a cell assay, claudin downregulation was preceded by upregulation of another protein called SNAIL1 that suppresses claudins, the cellular components that keep the junctions tight. What's more, inhibiting claudin expression in a cell assay or stimulating the Toll-like receptors in an animal model loosened the junctions between cells and promoted bacterial movement across the epithelium.

"This study provides an understanding of how microbes gain access into their host to affect its physiology," concludes Weiser.


'/>"/>

Contact: Karen Kreeger
karen.kreeger@uphs.upenn.edu
215-349-5658
University of Pennsylvania School of Medicine
Source:Eurekalert  

Related biology news :

1. GW researchers receive award from NCI to study cancer from a neglected tropical disease
2. Study finds golden algae responsible for killing millions of fish less toxic in sunlight
3. Study reveals important aspects of signaling across cell membranes in plants
4. Study hints at antibiotic overuse in home-care patients
5. E. coli bacteria more likely to develop resistance after exposure to low levels of antibiotics, reports a study in Microbial Drug Resistance
6. New study supports Darwins hypothesis on competition between species
7. Social scientists study impact of human adult stem cell research
8. Scripps Research scientist wins $1.9 million grant to study malaria
9. Mountain pine beetle activity may impact snow accumulation and melt, says CU-Boulder study
10. Study finds widespread stream biodiversity declines at low levels of urban development
11. Environmental engineering students and faculty study Passaic River pollution
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Gatekeepers: Penn study discovers how microbes make it past tight spaces between cells
(Date:3/15/2016)... 15, 2016 --> ... Transparency Market Research "Digital Door Lock Systems Market - Global ... 2023," the global digital door lock systems market in terms ... and is forecast to grow at a CAGR of 31.8% ... and medium enterprises (MSMEs) across the world and high industrial ...
(Date:3/14/2016)... Allemagne, March 14, 2016 ... - --> - Renvoi : image disponible ... --> --> DERMALOG, ... fournit de nouveaux lecteurs d,empreintes digitales pour l,enregistrement ... DERMALOG sera utilisé pour produire des cartes d,identité ...
(Date:3/10/2016)... , March 10, 2016 ... market research report "Identity and Access Management Market by ... Compliance, and Governance), by Organization Size, by Deployment, by ... published by MarketsandMarkets, The market is estimated to grow ... Billion by 2020, at a Compound Annual Growth Rate ...
Breaking Biology News(10 mins):
(Date:4/29/2016)... ... April 29, 2016 , ... Intelligent Implant Systems announced today that ... 510(k) for sale in the United States. These components expand the capabilities of ... With one-level sales beginning in October of 2015, the company has seen significant sales ...
(Date:4/28/2016)... YORK , April 28, 2016 ... acceleration company reports the Company,s CEO  was featured ... titled Accelerators Enter When VCs Fear To Tread: ... Science Leader magazine is an essential ... for everything from emerging biotechs to Big Pharmas. ...
(Date:4/28/2016)... ... April 28, 2016 , ... As ... recruiting top industry experts, and expanding its LATAM network and logistics capabilities. ... clients to manage their clinical trial projects. , The expansion will provide unmatched ...
(Date:4/27/2016)... ... April 27, 2016 , ... Shimadzu Scientific ... the Spring 2016 Marijuana Business Conference and Expo. Shimadzu’s high-performance instruments enable laboratories ... and more. Expo attendees can stop by booth 1021 to learn how Shimadzu’s ...
Breaking Biology Technology: