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Intestinal lactobacilli: allies in cases of undernutrition

In cases of chronic undernutrition, certain kinds of intestinal lactobacillus bacteria help maintain host growth by stimulating digestive enzyme expression and activity. Joint efforts between teams at CNRS and INRA have identified the influence of D-alanylated teichoic acids on bacterial cell walls in the bacteria/host dialogue at the root of this beneficial effect. This study was published on 9 October 2017 in Nature Microbiology.

Lactobacillus helveticus ATCC 12046 stained with fluorochrome. © INRA, BOYAVAL Patrick
Updated on 10/25/2017
Published on 10/19/2017

Lactobacillus plantarum, a bacteria found in intestinal microbiota. © INRA, Thierry Meyleuc
Lactobacillus plantarum, a bacteria found in intestinal microbiota © INRA, Thierry Meyleuc

The impact of undernutrition on intestinal microbiota

According to the World Health Organization, over 150 million children around the world suffer from undernutrition in 2017. The condition has serious adverse effects on the growth of over 40 million of them. Recent studies have shown that in addition to causing nutritional deficiencies, undernutrition modifies the establishment and maturation of intestinal bacteria communities (or ‘microbiota’). The condition encourages colonisation by pathogenic bacteria at the expense of other, normally present strains which are beneficial to health in general and to intestinal physiology in particular.

Intestinal lactobacilli support growth by stimulating the production of digestive enzymes

Using animal models, François Leulier (1) and his team previously demonstrated the important role played by ‘healthy’ microbiota in attenuating the harmful effects of chronic undernutrition on growth. The central role, maintained over the course of evolution, of certain commensal bacteria – lactobacilli – was identified in particular (2). The team showed that these lactobacilli promoted growth in their host by directly stimulating the expression and activity of digestive enzymes, thus increasing digestive efficiency (in particular the digestion of proteins) (3). This results in the improved absorption of nutrients and improved overall digestive efficiency despite undernutrition.

Bacterial influence in this mechanism identified

Joint research carried out with Marie-Pierre Chapot-Chartier’s team (4) allowed scientists to identify the factor which triggers this mechanism in a Drosophila-Lactobacillus plantarum model. The modification (D-alanylation) of teichoic acids, a major component of a lactobacillus cell wall, leads to an increase in the production of digestive enzymes by the intestinal cells of Drosophila.  These results were obtained by identifying mutant strains of lactobacillus which lacked D-alanylated teichoic acids and were incapable of supporting host growth in the presence of undernutrition.

The use of lactobacilli for undernourished children

The next step in this research will be to identify how the host recognises modified teichoic acids in lactobacillus cell walls and how it triggers a signal to increase the production of digestive enzymes.

Other studies carried out at François Leulier’s laboratory recently established that these same bacteria influence post-natal growth in mice (2). These new findings pave the way towards the study of these bacterial compounds and how they are recognised by intestinal cells in the regulation of growth in mammals. Another possibility is the development of innovative therapeutic strategies combining re-nutrition and the use of microbial strains or compounds in children who suffer from periods of undernutrition.  
 
(1) Institute of Functional Genomics of Lyon (CNRS/ENS Lyon/Université Claude Bernard/INRA).
(2) References: Storelli G. et al. Cell Metab. 2011 Sep 7;14(3):403-14. doi: 10.1016/j.cmet.2011.07.012. Schwarzer M. et al. Science, 2016 Feb 19; 351(6275):854-7.
(3) Reference: Erkosar B. et al. Cell Host and Microbe, 2015 Oct 14; 18(4):445-55.
(4) Micalis Institute (INRA/AgroParisTech/Université Paris-Saclay).

Contact(s)
Scientific contact(s):

Associated Division(s):
Microbiology and the Food Chain , Nutrition, Chemical Food Safety and Consumer Behaviour
Associated Centre(s):
Jouy-en-Josas

Reference

Matos R, Schwarzer M, Gervais H, Courtin P, Joncour P, Gillet B, Ma D, Bulteau AL, Martino ME, Hughes S, Chapot-Chartier MP, Leulier F. 2017. D-alanylation of teichoic acids contributes to Lactobacillus plantarum-mediated Drosophila growth during chronic undernutrition. Nature Microbiology. Advance Online Publication Oct 9th 2017; http://dx.doi.org/10.1038/s41564-017-0038-x