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:7/20/2017)... Delta (NYSE: DAL ) customers now can use ... Reagan Washington National Airport (DCA). ... Delta launches biometrics to board aircraft at Reagan Washington ... Delta,s biometric boarding pass experience that ... integrated into the boarding process to allow eligible Delta SkyMiles Members who ...
(Date:5/23/2017)... May 23, 2017  Hunova, the first robotic gym for the rehabilitation ... officially launched in Genoa, Italy . The first 30 ... and the USA . The technology was developed and ... by the IIT spin-off Movendo Technology thanks to a 10 million euro ... Release, please click: ...
(Date:4/24/2017)... -- Janice Kephart , former 9/11 Commission ... LLP (IdSP) , today issues the following statement: ... 6, 2017 Executive Order: Protecting the Nation ... instilled with greater confidence, enabling the reactivation of ... are suspended by until at least July 2017). ...
Breaking Biology News(10 mins):
(Date:10/7/2017)... ... October 06, 2017 , ... ... launched its ProxiMeta™ Hi-C metagenome deconvolution product, featuring the first commercially available ... bioinformatics software to perform Hi-C metagenome deconvolution using their own facilities, supplementing ...
(Date:10/6/2017)... (PRWEB) , ... October 06, 2017 , ... ... entrepreneurship within the healthcare and technology sector at their fourth annual Conference where ... featuring 30 inspiring speakers and the ELEVATE pitch competition showcasing early stage digital ...
(Date:10/5/2017)... , ... October 05, 2017 , ... LabRoots , ... scientists from around the world, is giving back to cancer research with a month-long ... , Now through October 31, shoppers can use promo code PinkRibbon to get ...
(Date:10/5/2017)... ... October 05, 2017 , ... NIH has awarded Circulomics ... Nanobind DNA/RNA extraction technology . Nanobind is a novel magnetic disk that contains ... can be used for a wide variety of sample preparation applications. The nanostructured ...
Breaking Biology Technology: