Gastric carcinoma is one of the most common causes of cancer-related deaths, primarily because most patients present at an advanced stage of the disease. The main cause of this cancer is the bacterium Helicobacter pylori, which chronically infects around half of all humans. However, unlike tumor viruses, bacteria do not deposit transforming genes in their host cells and how they are able to cause cancer has so far remained a mystery.
An interdisciplinary research team has now discovered that the bacterium sends stem cell renewal in the stomach into overdrive - and stem cell turnover has been suspected by many scientists to play a role in the development of cancer. By showing that the stomach contains two different stem cell types, which respond differently to the same driver signal, they have uncovered a new mechanism of tissue plasticity. It allows tuning tissue renewal in response to bacterial infection.
While it is now clear that most cases of stomach cancer are linked to chronic infections with H. pylori, the mechanism remains unknown.
Researchers overturned the established dogma to show that H. pylori not only infects the surface cells, which are about to be sloughed off, but that some of the bacteria manage to invade deep into the glands and reach the stem cell compartment. They have now found that these stem cells do indeed respond to the infection by increasing their division - producing more cells and leading to the characteristic thickening of the mucosa observed in affected patients.
They used different transgenic mice to trace cells expressing particular genes, as well as all their daughter cells. The results, published in Nature indicate that the stomach glands contain two different stem cell populations. Both respond to a signalling molecule called Wnt, which maintains stem cell turnover in many adult tissues.
Crucially, they discovered that myofibroblast cells in the connective tissue layer directly underneath the glands produce a second stem cell driver signal, R-spondin, to which the two stem cell populations responded differently. It is this signal, which turned out to control the response to H. pylori: Following infection, the signal is ramped up, silencing the more slowly cycling stem cell population and putting the faster cycling stem cell population into overdrive.
These findings substantiate the rising awareness that chronic bacterial infections are strong promoters of cancer. 'Our findings show that an infectious bacterium can increase stem cell turnover', says the senior author. 'Since H. pylori causes life-long infections, the constant increase in stem cell divisions may be enough to explain the increased risk of carcinogenesis observed,' and another author adds: 'Our new findings shed light on the intriguing ways through which chronic bacterial infections disturb tissue function and provide invaluable clues on how bacteria, in general, may increase the risk of cancer'.
https://www.mpg.de/11437780/stomach-cancer-helicobacter-pylori-infection
Latest News
Abusive drugs hijack natura…
By newseditor
Posted 23 Apr
Mechanism of action of the…
By newseditor
Posted 23 Apr
Role of fat in rare neurolo…
By newseditor
Posted 23 Apr
How protein synthesis in de…
By newseditor
Posted 22 Apr
Atlas of mRNA variants in d…
By newseditor
Posted 22 Apr
Other Top Stories
Novel chip-based gene expression tool analyzes RNA quickly and accu…
Read more
Vitamin C in the body can be tracked by fluorescence
Read more
'Smart' contact lenses monitor glucose levels in tears
Read more
Anxiety Cells' Identified in the Brain's Hippocampus
Read more
Cryo-EM structure of full length serotonin receptor
Read more
Protocols
A programmable targeted pro…
By newseditor
Posted 23 Apr
MemPrep, a new technology f…
By newseditor
Posted 08 Apr
A tangible method to assess…
By newseditor
Posted 08 Apr
Stem cell-derived vessels-o…
By newseditor
Posted 06 Apr
Single-cell biclustering fo…
By newseditor
Posted 01 Apr
Publications
Exploiting pancreatic cance…
By newseditor
Posted 23 Apr
Structure of antiviral drug…
By newseditor
Posted 23 Apr
Type-I-interferon-responsiv…
By newseditor
Posted 23 Apr
Selenium, diabetes, and the…
By newseditor
Posted 23 Apr
Long-term neuropsychologica…
By newseditor
Posted 23 Apr
Presentations
Hydrogels in Drug Delivery
By newseditor
Posted 12 Apr
Lipids
By newseditor
Posted 31 Dec
Cell biology of carbohydrat…
By newseditor
Posted 29 Nov
RNA interference (RNAi)
By newseditor
Posted 23 Oct
RNA structure and functions
By newseditor
Posted 19 Oct
Posters
A chemical biology/modular…
By newseditor
Posted 22 Aug
Single-molecule covalent ma…
By newseditor
Posted 04 Jul
ASCO-2020-HEALTH SERVICES R…
By newseditor
Posted 23 Mar
ASCO-2020-HEAD AND NECK CANCER
By newseditor
Posted 23 Mar
ASCO-2020-GENITOURINARY CAN…
By newseditor
Posted 23 Mar