Exoproteomics for Better Understanding Pseudomonas aeruginosa Virulence Salome Sauvage, Julie Hardouin To cite this version: Salome Sauvage, Julie Hardouin. Exoproteomics for Better Understanding Pseudomonas aeruginosa Virulence. Toxins, MDPI, 2020, 12 (9), pp.571. 10.3390/toxins12090571. hal-02991487 HAL Id: hal-02991487 https://hal.archives-ouvertes.fr/hal-02991487 Submitted on 6 Nov 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. toxins Review Exoproteomics for Better Understanding Pseudomonas aeruginosa Virulence Salomé Sauvage 1,2 and Julie Hardouin 1,2,* 1 Polymers, Biopolymers, Surface Laboratory, UMR 6270 CNRS, University of Rouen, CEDEX, F-76821 Mont-Saint-Aignan, France; [email protected] 2 PISSARO Proteomics Facility, IRIB, F-76820 Mont-Saint-Aignan, France * Correspondence: [email protected]; Tel.: +33-(0)2-3514-6709 Received: 2 July 2020; Accepted: 1 September 2020; Published: 4 September 2020 Abstract: Pseudomonas aeruginosa is the most common human opportunistic pathogen associated with nosocomial diseases. In 2017, the World Health Organization has classified P. aeruginosa as a critical agent threatening human health, and for which the development of new treatments is urgently necessary. One interesting avenue is to target virulence factors to understand P. aeruginosa pathogenicity. Thus, characterising exoproteins of P.aeruginosa is a hot research topic and proteomics is a powerful approach that provides important information to gain insights on bacterial virulence. The aim of this review is to focus on the contribution of proteomics to the studies of P.aeruginosa exoproteins, highlighting its relevance in the discovery of virulence factors, post-translational modifications on exoproteins and host-pathogen relationships. Keywords: exoproteomics; Pseudomonas aeruginosa; virulence factors; post-translational modifications; secreted proteins Key Contribution: Proteomics is now a well-established methodology for the discovery of new virulence factors secreted by bacteria. This review focuses on its importance in this research area. 1. Introduction Pseudomonas aeruginosa is a common environmental Gram-negative bacterium, which is part of the Pseudomonadaceae. This bacterium is aerobic, motile, non-sporing, and ubiquitous because of its ability to survive in large environment range [1]. This universal distribution suggests a remarkable degree of genetic and physiological plasticity to environmental changes [2]. P. aeruginosa is also the most common human opportunistic pathogen associated with nosocomial diseases [2]. In 2017, the World Health Organization has classified P. aeruginosa as a critical agent threatening human health and for which the development of new treatments is urgently necessary [3]. Indeed, P. aeruginosa is able to avoid the innate host immunity and is highly resistant to a wide range of antimicrobial agents [4], making its infections very difficult to treat [2]. Discovering of new antibiotic drugs can be a solution. Nevertheless, new bacterial resistance can appear [5]. A strategy more and more considered is to reduce bacterial virulence, i.e., not kill the bacteria [6]. With this anti-virulence strategy, the selection pressure that could be exerted does not engage bacterial survival, suggesting that this type of strategy would limit the selection of resistant strains. In this context, the study of the virulence factors is an interesting avenue to understand P. aeruginosa pathogenicity. P. aeruginosa possesses a large arsenal of virulence systems contributing to the success of its infection and colonization [7]. Among them, we can cite quorum sensing (QS) and type 2, 3, and 6 secretion systems (T2SS, T3SS, and T6SS respectively) with their secreted proteins and toxins. QS is an intercellular bacterial communication system dependent on cell density, which allows individual Toxins 2020, 12, 571; doi:10.3390/toxins12090571 www.mdpi.com/journal/toxins Toxins 2020, 12, 571 2 of 19 cells to act as a community [4]. This system would control around 10% of the P. aeruginosa genome, Toxins 2020, 12, x FOR PEER REVIEW 2 of 19 including survival genes, genes coding for virulence factors and biofilm formation [7–9]. T2SS, T3SS, and T6SSan intercellular are major secretion bacterial systemscommunication in P. aeruginosa system dependent(Figure1). on Their cell density, secreted which products allows act individual as virulence factors:cells they to act support as a community bacteria to[4]. survive This system in host would by avoidingcontrol around the immune 10% of the host P. aeruginosa system and genome, allowing them toincluding provoke survival infection genes, [4]. genes T2SS coding secretes for severalvirulence proteases factors and in biofilm the extracellular formation [7–9]. medium, T2SS, including T3SS, elastasesand LasA T6SS andare major LasB, proteasesecretion IV,systems phospholipase in P. aeruginosa C, and (Figure exotoxin 1). Their A [7 ].secreted LasB is products a metalloprotease act as able tovirulence destroy factors: or inactivate they support biological bacteria tissues to survive in host in organisms host by avoiding [10]. LasAthe immune is involved host system in proteolysis and and degradationallowing them of to the provoke host protein infection elastin [4]. T2SS and secr enhancesetes several the proteases elastolytic in the activity extracellular of LasB medium, and other including elastases LasA and LasB, protease IV, phospholipase C, and exotoxin A [7]. LasB is a proteases. Protease IV and phospholipase C participate in P. aeruginosa keratitis and P. aeruginosa metalloprotease able to destroy or inactivate biological tissues in host organisms [10]. LasA is acute lung injury and inflammation, respectively [7]. Exotoxin A inhibits protein synthesis by its involved in proteolysis and degradation of the host protein elastin and enhances the elastolytic ADP-ribosylactivity transferaseof LasB and activityother proteases. leading Protease to cell deathIV and andphospholipase depresses C host participate response in P. to aeruginosa infection [7]. All ofkeratitis these secreted and P. aeruginosa proteins acute can belung exported injury and through inflammation, the cytoplasmic respectively membrane[7]. Exotoxin via A inhibits Sec or Tat machineryprotein [11 synthesis]. T3SS consistsby its ADP-ribosy in an injectisome,l transferase synthetized, activity leading and assembledto cell death on and the depresses bacterial host surface, whenresponse the bacterium to infection is next [7]. to All host of cellsthese [ 12secreted]. It injects proteins toxins can directlybe exported in the through cytoplasm the cytoplasmic of target cells and fourmembrane exotoxins via Sec have or Tat been machinery identified [11]. in T3SSP. aeruginosa consists instrains: an injectisome, ExoS, ExoT,synthetized, ExoU, and and assembled ExoY. ExoS and ExoTon the target bacterial and surface, inactivate when di fftheerent bacterium substrates is next including to host cells GTPases [12]. It injects and adaptor toxins directly proteins, in the which triggercytoplasm actin cytoskeleton of target cells dismantlement and four exotoxins and thenhave cellbeen apoptosis identified [in12 P.]. aeruginosa ExoU permeabilizes strains: ExoS, the ExoT, plasma ExoU, and ExoY. ExoS and ExoT target and inactivate different substrates including GTPases and membrane and leads to necrotic cell death by its phospholipase activity [12]. The toxicity of ExoY, adaptor proteins, which trigger actin cytoskeleton dismantlement and then cell apoptosis [12]. ExoU an adenylate cyclase, remains unknown [12]. T6SS is composed by core-conserved genes (TssA-C, permeabilizes the plasma membrane and leads to necrotic cell death by its phospholipase activity TssE-G,[12]. TssJ-M, The toxicity Hcp, VgrG,of ExoY, and an ClpV)adenylate which cyclase, form remains its key unknown structures [12]. [13 T6SS]. It is is composed able to inject by core- effector proteinsconserved inside eukaryoticgenes (TssA-C, host TssE-G, cells, prokaryoticTssJ-M, Hcp, competitorsVgrG, and ClpV) and which the environment, form its key structures providing [13]. fitness and survivalIt is able advantages to inject effector to P. aeruginosa proteins inside[14–16 eukaryotic]. Indeed, host T6SS cells, has aprokaryotic large range competitors of cellular and targets the and uses anenvironment, arsenal of toxinsproviding and fitness effectors and survival to subvert advantages or kill prey to P. cells.aeruginosa Thus, [14–16]. three Indeed, T6SS clusters T6SS has named a H1-T6SS,large H2-T6SS, range of cellular and H3-T6SS targets and are encodeduses an arsenal by P. aeruginosaof toxins and[14 effectors]. Among to subvert them, H1-T6SSor kill prey transports cells. at leastThus, seven three antibacterial T6SS clusters toxins named (Tse1-Tse7) H1-T6SS, [H2-T6SS,14], which and target H3-T6SS membrane, are encoded cell by wall, P. aeruginosa nucleic acids [14]. and have otherAmong biological them, H1-T6SS functions transports [14]. H3-T6SS at least seven is involved antibacterial