Intestinal cells stave off bacteria by purging

November 24, 2016, CNRS
Drosophila epithelium. An enterocyte (green) dumps its damaged contents into the intestinal lumen. Also visible are actin filaments (red) and DNA (blue). Credit: © Catherine Socha.

Though purging is not prescribed as often as it was centuries ago, intestinal cells known as enterocytes frequently resort to this age-old remedy. Researchers from the Immune Response and Development in Insects (CNRS), Molecular Immunorheumatology (INSERM / Université de Strasbourg), and PAM Food Science and Microbiological Processes (AgroSup Dijon / Université de Bourgogne) laboratories have demonstrated that enterocytes attacked by pathogenic bacteria rapidly purge themselves of most of their contents. This protects them from infection and leads to a drastic though temporary thinning of the intestinal lining, or epithelium. This work, published on November 23 in Cell Host & Microbe, may eventually shed light on inflammatory bowel diseases like Crohn's disease.

Serratia marcescens is an opportunistic bacterium common throughout our environment. Drosophila flies fed a steady diet of S. marcescens die in days. However, analysis of the intestinal epithelium every 24 hours reveals no apparent damage. The researchers decided to study what happens during the first few hours after infection. They found that, during this initial period, the epithelium is remarkably thinner, and seems almost to have disappeared. But it recovers its original thickness in the hours that follow. Enterocytes lose much of their cytoplasm, having expelled most of their contents, though not their nuclei. These cells thereby rid themselves of damaged organelles, of some of the bacteria attempting to penetrate the , and bacterial toxins. This process leaves the epithelium temporarily thinner.

The presence of hemolysin, a bacterial toxin that forms pores in the membranes of its target cells, triggers cell purging. The researchers showed that a mutant strain of S. marcescens unable to secrete hemolysin is for this reason actually more virulent. Though the toxin is no longer at its disposal, its absence means the enterocytes are not triggered to initiate protective purging, and the bacteria can then damage the epithelium with other virulence factors. Further studies have shown that this thinning and regrowth of the is characteristic of bees, mice, and humans alike. More research will be necessary to determine the molecular mechanisms involved and, more broadly, whether anomalies in this process can help elucidate the causes of inflammatory bowel diseases like Crohn's disease.

Explore further: 'Normal' bacteria vital for keeping intestinal lining intact

More information: Enterocyte purge and rapid recovery is a resilience reaction of the gut epithelium to pore-forming toxin attack. Lee KZ, Lestradet M, Socha C, Schirmeier S, Schmitz A, Spenlé C, Lefebvre O, Keime C, Yamba WM, Bou Aoun R, Liegeois S, Shwab Y, Simon-Assmann, P, Dalle F, Ferrandon D. Cell Host Microbe. 23 Nov 2016.

Related Stories

'Normal' bacteria vital for keeping intestinal lining intact

August 1, 2014

Scientists at Albert Einstein College of Medicine of Yeshiva University have found that bacteria that aid in digestion help keep the intestinal lining intact. The findings, reported online in the journal Immunity, could yield ...

Molecular docking site of a bacterial toxin identified

June 9, 2015

Clostridium difficile is a dangerous intestinal bacterium that can cause severe diarrhoea and life-threatening intestinal infections after long-term treatment with antibiotics. The pharmacologists and toxicologists Prof. ...

Intestinal cells 'remodel' in response to a fatty meal

November 2, 2016

New work led by Carnegie's Steven Farber sheds light on how form follows function for intestinal cells responding to high-fat foods that are rich in cholesterol and triglycerides. Their findings are published in the Journal ...

First step to new therapy for chronic bowel disease

July 6, 2010

Scientists associated with VIB (Flanders Institute for Biotechnology) and Ghent University (UGent) have discovered that A20 protein plays an important protective role in diseases associated with chronic bowel inflammation. ...

Recommended for you

Common weed killer linked to bee deaths

September 24, 2018

The world's most widely used weed killer may also be indirectly killing bees. New research from The University of Texas at Austin shows that honey bees exposed to glyphosate, the active ingredient in Roundup, lose some of ...

Custom circuits for living cells

September 24, 2018

A team of Caltech researchers has developed a biological toolkit of proteins that can be assembled together in different ways, like Legos, to program new behaviors in cells. As a proof-of-concept, they designed and constructed ...

Birds' voiceboxes are odd ducks

September 24, 2018

Birds sing from the heart. While other four-limbed animals like mammals and reptiles make sounds with voiceboxes in their throats, birds' chirps originate in a unique vocal organ called the syrinx, located in their chests. ...

Desert ants have an amazing odor memory

September 24, 2018

Scientists at the Max Planck Institute for Chemical Ecology used behavioral experiments to show that desert ants quickly learn many food odors and remember them for the rest of their lives. However, their memory for nest ...

Some female termites can reproduce without males

September 24, 2018

Populations of the termite species Glyptotermes nakajimai can form successful, reproducing colonies in absence of males, according to a study published in the open access journal BMC Biology.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.