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:4/3/2017)... WASHINGTON , April 3, 2017 /PRNewswire-USNewswire/ ... single-cell precision engineering platform, detected a statistically ... cell product prior to treatment and objective ... highlight the potential to predict whether cancer ... prior to treatment, as well as to ...
(Date:3/29/2017)...  higi, the health IT company that operates the ... , today announced a Series B investment from ... The new investment and acquisition accelerates higi,s strategy to ... population health activities through the collection and workflow integration ... collects and secures data today on behalf of over ...
(Date:3/24/2017)... Research and Markets has announced the addition of the ... Industry Forecast to 2025" report to their offering. ... The Global Biometric Vehicle Access ... 15.1% over the next decade to reach approximately $1,580 million by ... and forecasts for all the given segments on global as well ...
Breaking Biology News(10 mins):
(Date:4/27/2017)... Tenn. , April 27, 2017  Pendant Biosciences, ... developing innovative surface modification and drug delivery technologies, today ... Johnson Innovation, JLABS @ Toronto . ... Executive Officer of Pendant Biosciences, noted, "We are excited ... Toronto community, and are honored to be ...
(Date:4/26/2017)... Beach, SC (PRWEB) , ... April 26, 2017 ... ... the mind, has teamed up with NASA to showcase the future of deep ... Space Launch System (SLS) rocket and Orion spacecraft and includes a guest appearance ...
(Date:4/26/2017)... , ... April 26, 2017 , ... ... demonstrating its new Bioflash MailGuardtm mail security screening solution at the National Postal ... Bioflash MailGuard system provides a fast, highly accurate, easy to use and low ...
(Date:4/26/2017)... Pa. , April 26, 2017  Genisphere ... delivery platform, has signed a collaborative and sponsored ... Dr. Silvia Muro . The overall goal ... and pharmacodynamics of various 3DNA designs and formulations ... involve targeting diseases of the vasculature as well ...
Breaking Biology Technology: