Listeria monocytogenes requires cellular respiration for NAD+ regeneration and pathogenesis

Abstract

Cellular respiration is essential for multiple bacterial pathogens and a validated antibiotic target. In addition to driving oxidative phosphorylation, bacterial respiration has a variety of ancillary functions that obscure its contribution to pathogenesis. We find here that the intracellular pathogen Listeria monocytogenes encodes two respiratory pathways which are partially functionally redundant and indispensable for pathogenesis. Loss of respiration decreased NAD+ regeneration, but this could be specifically reversed by heterologous expression of a water-forming NADH oxidase (NOX). NOX expression fully rescued intracellular growth defects and increased L. monocytogenes loads >1,000-fold in a mouse infection model. Consistent with NAD+ regeneration maintaining L. monocytogenes viability and enabling immune evasion, a respiration-deficient strain exhibited elevated bacteriolysis within the host cytosol and NOX expression rescued this phenotype. These studies show that NAD+ regeneration represents a major role of L. monocytogenes respiration and highlight the nuanced relationship between bacterial metabolism, physiology, and pathogenesis.

Distinct energy-coupling factor transporter subunits enable flavin acquisition and extracytosolic trafficking for extracellular electron transfer inListeria monocytogenes

“…We previously found that the foodborne pathogen Listeria monocytogenes possesses EET activity that enhances anaerobic growth. 9,10 We further identified an eight-gene cluster responsible for EET (Figure 1B). 11 Within this cluster, we found that the gene fmnB encoded an ApbE-like protein that flavinylated a second protein from the cluster, PplA, at two sites.…”

Listeria monocytogenesrequires DHNA-dependent intracellular redox homeostasis facilitated by Ndh2 for survival and virulence

“…Importantly, we had previously demonstrated that exogenous DHNA does not restore respiration and membrane potential (31). Taken together, these data suggest that DHNA, independent of its role in respiration, restores cellular redox homeostasis, subsequently shifting the fermentative output from lactate back towards acetate that likely drives ATP production through acetate kinase (24,34).…”

“…We had previously demonstrated that L. monocytogenes mutants lacking the key MK biosynthetic intermediate DHNA were attenuated, in part, independent of loss of respiration (29,31,32). We hypothesized that restoration of NAD + pools might rescue these virulence defects similar to the rescue observed for mutants lacking components of the respiratory chains (34). To test this hypothesis, we assessed NAD + /NADH levels in ΔmenB, ΔmenI and ΔmenA mutants +/expression of NOX in trans.…”

“…Therefore, although DHNA-deficient strains of L. monocytogenes possess the downstream enzymes to produce MK or DMK, these data suggest that exogenous DHNA is not utilized to promote either aerobic or anaerobic cellular respiration. Recent work from Rivera-Lugo et al sought to dissect the relative importance of maintaining redox homeostasis versus PMF generation for the pathogenesis of L. monocytogenes using a water-forming NADH oxidase (NOX) that specifically regenerates NAD + independent of respiration and PMF function (34).…”

Physiological Benefits of Oxygen-Terminating Extracellular Electron Transfer

“…Given its significance, it will be of great interest to examine oxygen-terminating EET in other bacteria besides P. aeruginosa and F. prausnitzii . For example, it would be of interest to test a human pathogen, Listeria monocytogenes , because it is suggested that L. monocytogenes utilizes EET pathway in oxygen reduction when the genes for terminal oxygen reductases in aerobic respiration are deleted ( 68 ). S. oneidensis MR-1 conducts electrode-terminating EET using outer membrane c -type cytochrome complexes ( 69 – 71 ).…”