Gut Microbes Send Signals to Host Mitochondria and control longevity!

Han et al Cell, Volume 169, Issue 7, 15 June 2017, Pages 1249–1262

A very interesting study looking at the role of gut microbiome on longevity.

Key findings

Certain bacterial strains/mutants protect the host from age-related diseases.

These bacterial mutants promote longevity through increased secretion of the polysaccharide colanic acid (CA). the common exopolysaccharide found in the Enterobacteriaceae. CA polymer consists glucose, galactose, fucose and glucuronic acid, together with acetate and pyruvate.

CA regulates mitochondrial dynamics in the host. Purified CA polymers are sufficient to promote longevity in the absence of bacteria.

The mitochondrial changes and longevity effects induced by CA are conserved across different species.

Mitochondria evolved from and share many metabolic pathways with bacteria. Thus, the microbiota may influence host by chemically communicating with their ancient intra-cellular relative, the mitochondria!! with CA serving as a messenger

Their results identified molecular targets for developing pro-longevity microbes

Good bacteria of the skin vs. skin disease causing bacteria

Nakatsuji T et al Science Translational Medicine  22 Feb 2017: Vol. 9, 4680

In this study Nakatsuji et al. report that strains of Staphylococcus (S. epidermidis and S. hominis) residing on the skin of healthy individuals produce a novel antimicrobial peptide (AMT) that can inhibit S. aureus that is known to aggravate symptoms of atopic dermatitis/eczema. They developed a probiotic lotion/cream of these good Staphylococcus strains. When applied to the fore arm of volunteers, within 24 hours, the probiotic lotion nearly eliminated S. aureus from their skin. Nonspecific antibacterial action by common pharmaceutical antibiotics could kill protective strains of Staphylococcus  and might therefore enhance the potential for recolonization by S. aureus. The selective activity of antimicrobials derived from normal flora would avoid this nonspecific effect and illustrates why bacteriotherapy that kills S. aureus but does not inhibit other beneficial strains could be superior. It remains to be seen how important this concept is in other skin diseases!