Open AccessModulation of cAMP levels by a conserved actinobacteria phosphodiesterase enzyme reduces antimicrobial tolerance in mycobacteria
Author(s) -
M. Thomson,
Gérald Larrouy-Maumus
Publication year - 2020
Publication title -
access microbiology
Language(s) - English
Resource type - Journals
ISSN - 2516-8290
DOI - 10.1099/acmi.ac2020.po0658
Subject(s) - antimicrobial , phosphodiesterase , microbiology and biotechnology , biology , mycobacterium smegmatis , enzyme , actinobacteria , biofilm , mycobacterium tuberculosis , bacteria , biochemistry , gene , tuberculosis , genetics , medicine , 16s ribosomal rna , pathology
Antimicrobial tolerance is the gateway to the development of antimicrobial resistance and is therefore a major issue that needs to be tackled. The second messenger, cyclic-AMP (cAMP) is conserved across all taxa of life. It is involved in propagating the signal from environmental stimuli and converting it into a response. In bacteria such as M. tuberculosis (Mtb), P. aeruginosa , V. cholerae and B. pertussis , cAMP has been implicated in virulence, regulation of metabolism and gene expression. Cyclic AMP signalling in mycobacteria is especially complex – with 16 enzymes that produce cAMP in Mtb alone. By discovery of a novel, actinobacteria conserved enzyme that degrades cAMP, we have developed a tool to modulate cAMP levels in mycobacteria. By using a combination of metabolomics, bioenergetics and time-to-kill assays, we show that when this enzyme is overexpressed in the model organism M. smegmatis , there is a 3.3 -fold decrease in intracellular cAMP levels. This was concomitant with 7-fold increased ATP. The unbalanced ATP/cAMP ratio consequently altered cell envelope permeability, compromised bioenergetics and most importantly, led to a decrease in the tolerance to various frontline antimicrobials. Taken together, this work provides clear evidence that cAMP is involved in antimicrobial tolerance in mycobacteria and that this may represent a promising new target for antimicrobial development.