Insights Into Nitric Oxide Modulated Quorum Sensing Pathways

Abstract

The emerging threat of drug resistant bacteria has prompted the investigation into bacterial signaling pathways responsible for pathogenesis. One such mechanism by which bacteria regulate their physiology during infection of a host is through a process known as quorum sensing (QS). Bacteria use QS to regulate community-wide gene expression in response to changes in population density. In order to sense these changes in population density, bacteria produce, secrete and detect small molecules called autoinducers. The most common signals detected by Gram-negative and Gram-positive bacteria are acylated homoserine lactones and autoinducing peptides (AIPs), respectively. However, increasing evidence has supported a role for the small molecule nitric oxide (NO) in influencing QS-mediated group behaviors like bioluminescence, biofilm production, and virulence. In this review, we discuss three bacteria that have an established role for NO in influencing bacterial physiology through QS circuits. In two Vibrio species, NO has been shown to affect QS pathways upon coordination of hemoprotein sensors. Further, NO has been demonstrated to serve a protective role against staphylococcal pneumonia through S-nitrosylation of a QS regulator of virulence.

Amphiphilic Nitroxide-Bearing Siloxane-Based Block Copolymer Coatings for Enhanced Marine Fouling Release

“…One of the most common nitroxides, 2,2,6,6-tetramethylpipiderine-1-oxyl (TEMPO), has been used in antifouling applications to inhibit proliferation and trigger dispersal of biofilms. − In one study, thin films of poly­(2,2,6,6-tetramethylpipiderine-1-oxyl) methacrylate (PTMA) reduced adhesion of Pseudomonas by 99.6% as compared to a poly­(methyl methacrylate) control . The mechanism of action is thought to rely on the nitroxide’s structural and electronic similarity to nitric oxide, which, in bacteria, is used as a signaling molecule in quorum sensing . Organic nitroxides and their precursors have also long been used as antioxidants and radical scavengers and have been shown to effectively quench hydroxyl, − peroxyl, carbon-centered, − and thiyl radicals but have yet to be explored for use against macroscopic fouling organisms.…”

“…42 The mechanism of action is thought to rely on the nitroxide's structural and electronic similarity to nitric oxide, which, in bacteria, is used as a signaling molecule in quorum sensing. 43 Organic nitroxides and their precursors have also long been used as antioxidants and radical scavengers and have been shown to effectively quench hydroxyl, 44−46 peroxyl, 47 carboncentered, 48−50 and thiyl radicals 51 but have yet to be explored for use against macroscopic fouling organisms. Because of this broad-spectrum behavior, nitroxides could be extremely effective additions to a fouling-release coating by quenching any oxidative or radical-based reactions at the adhesive interface, thereby weakening surface attachment.…”

Recent Developments in Pharmacological Effect, Mechanism and Application Prospect of Diazeniumdiolates

“…Nitric oxide (NO) is a simple and unstable free radical, which is considered as a versatile endogenous molecule and a crucial signaling factor in many biochemistry and physiological pathways. NO participates in such pathophysiological processes as vasodilation, signaling, and endocrine regulation (Heckler and Boon, 2019). On the one hand, depletion of NO or attenuation of its effector system may result in hypertension, angina and impotence.…”

Le monoxyde d’azote: Une arme du système immunitaire pour brouiller les communications entre bactéries

“…Chez un grand nombre d'espèces bactériennes, le quorum sensing contrôle certains phénomènes collectifs comme par exemple la dynamique de formation et la dispersion du biofilm, qui peuvent être impliqués dans la transition d'un état commensal vers un état pathogène. L'interférence du NO avec le quorum sensing pourrait donc également moduler la dynamique du biofilm, renforçant ainsi le contrôle de la virulence des microorganismes hébergés [11]. Le NO à faible concentration est une molécule de signalisation importante chez les Mammifères [12].…”