Host cholesterol modulates the generation and enrichment of persisters during Mycobacterium tuberculosis infection

A worldwide increase in the frequency of multidrug-resistant and extensively-drug-resistant cases of tuberculosis is mainly due to the therapeutic noncompliance associated with a lengthy treatment regimen. This protracted regimen is attributed to a supposedly nonreplicating and metabolically inert subset of the Mycobacterium tuberculosis (Mtb) population, called 'persisters'. We have earlier reported that the utilization of host cholesterol is essential for Mtb persistence. However, the mechanism underlying stochastic generation and enrichment of persisters is not fully known. In this study, we showed that cholesterol-induced activation of ribonuclease toxin (VapC12) inhibits translation by targeting proT tRNA and is critical for the generation of persisters in a heterogeneous Mtb population. A vapC12-null mutant strain (?vapC12) failed to persist and showed hypervirulence in a guinea pig model of tuberculosis. We identify a novel strategy through which cholesterol-specific activation of a toxin–antitoxin (TA) module in Mtb leads to the persister formation during infection. Our study provides an opportunity for targeting persisters, a new paradigm facilitating tuberculosis drug development. Overall design: Examination of the effect of glycerol and cholesterol on Wild type Mtb (H37Rv) and mutant Mtb strain (vapC12 mutant) during rifampicin treatment