A Pseudomonas aeruginosa‐secreted protease modulates host intrinsic immune responses, but how?

Abstract

Recently, we found that the Pseudomonas aeruginosa type II secreted protease IV functions as a unique Arabidopsis innate immunity elicitor. The protease IV-activated pathway involves G protein signaling and raises the question of how protease elicitation leads to the activation of G protein-mediated signaling, because plants do not appear to have metazoan-like G protein-coupled receptors. Importantly, our data suggest that Arabidopsis has evolved a mechanism to detect the proteolytic activity of a pathogen-encoded protease, supporting the host-pathogen arms race model. In the case of opportunistic multi-host pathogens like P. aeruginosa, however, it is not plausible that P. aeruginosa is simultaneously co-evolving in a gene-for-gene manner with all of its potential hosts, which include plants, nematodes, insects, and mammals. This prompts us to ask what is the driving force for co-evolution of defense response in Arabidopsis and pathogenesis of P. aeruginosa, which might not have been subject to iterative cycles of evolutionary selections.

Detection of gut microflora and enzymes using metagenomics and metaproteomics in silkworm, Bombyx mori

“…Similarly nano-vaccine developed using outer membrane protein (OmpW) of Aeromonas hydrophila showed a dose dependent Immunity in Rohu sh(Labeo rohita) [41]. Recent research enlightened Pseudomonas aeruginosa as immune elicitor by secreting type II protease IV functions in Arabidopsis [42]. Protease IV activates pathway involving G protein signaling in immune function.…”

A response of the imbibed dormant red rice caryopsis to biotic challenges involves extracellular pH increase to elicit superoxide production

“…DAMPs are danger signals originated from the host because of deleterious activities of microbial hydrolytic enzymes (Gust et al , 2017). As bacterial proteases PrpL, secreted by Pseudomonas aeruginosa , and ArgC, by Xanthomonas campestris , can activate an immune response in Arabidopsis that includes induction of an oxidative burst (Cheng et al , 2015), it appears that plants have evolved a mechanism to detect the proteolytic activity of pathogen-encoded proteases (Cheng et al , 2015; Cheng, 2016). Although it remains to be determined how the protease triggers the activation of the immune pathway (Cheng, 2016), it has been suggested that pathogen-secreted proteases could release host polypeptides that function as DAMPs and are subsequently recognized by immune receptors (Cheng et al , 2015).…”

“…Although it remains to be determined how the protease triggers the activation of the immune pathway (Cheng, 2016), it has been suggested that pathogen-secreted proteases could release host polypeptides that function as DAMPs and are subsequently recognized by immune receptors (Cheng et al , 2015). This mechanism, or a similar one (Cheng, 2016), appears to occur in red rice seeds too. As P. aeruginosa is an opportunistic bacterial pathogen and X. campestris is a true pathogen, whereas S. griseus is non-pathogenic, the mechanism to detect the proteolytic activity of damaging microbial proteases might be a rather generic one.…”

Virulence Factors of Pseudomonas Aeruginosa and Antivirulence Strategies to Combat Its Drug Resistance

“…Protease IV is significantly associated with corneal virulence of P. aeruginosa ( Bradshaw et al., 2018 ). Not only can protease IV interfere with host immunity by degrading various biologically important molecules, such as complement components, immunoglobulins, and surfactant proteins, but also damage host tissues and enhance bacterial infection through degradation of fibrinogen, lactoferrin, transferrin, and elastin ( Engel et al (1998) ; Malloy et al., 2005 ; Cheng, 2016 ; O'Callaghan et al., 2019 ). Since protease IV is a serine protease, known serine protease inhibitors that block its enzymatic activity may be developed into therapeutics to prevent tissue damage caused by P. aeruginosa infection.…”