Role of Inflammasome-independent Activation of IL-1β by the<i>Pseudomonas aeruginosa</i>Protease LasB

Sun, Josh; LaRock, Doris L.; Skowronski, Elaine A.; Kimmey, Jacqueline M.; Olson, Joshua; Jiang, Zhenze; O’Donoghue, Anthony J.; Nizet, Victor; LaRock, Christopher N.

doi:10.1101/2020.05.18.101303

Cited by 3 publications

(2 citation statements)

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“…Transgenic IL-1R reporter cells were used to measure matured IL-1␤ essentially as previously described (21). These reporter cells were modified (29) to use a luciferase-based instead of an alkaline phosphatase-based readout, to eliminate signal interference from bacterial and murine alkaline phosphatases. Luciferase activity was measured with Steady-Luc luciferin (Biotium) on a multimode plate reader (PerkinElmer).…”

Section: Methodsmentioning

confidence: 99%

Group A Streptococcus Infection of the Nasopharynx Requires Proinflammatory Signaling through the Interleukin-1 Receptor

et al. 2020

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Group A Streptococcus (GAS) is the etiologic agent of numerous high morbidity and high mortality diseases. Infections are typically highly proinflammatory. During the invasive infection necrotizing fasciitis, this is in part due to the GAS protease SpeB directly activating interleukin-1β (IL-1β) independent of the canonical inflammasome pathway. The upper respiratory tract is the primary site for GAS colonization, infection, and transmission, but the host-pathogen interactions at this site are still largely unknown. In the murine nasopharynx, we find SpeB enhanced IL-1β-mediated inflammation and the chemotaxis of neutrophils. However, neutrophilic inflammation did not restrict infection, and instead promoted GAS replication and disease. Inhibiting IL-1β or depleting neutrophils, which both promote invasive infection, prevented GAS infection of the nasopharynx. Mice pre-treated with penicillin became more susceptible to GAS challenge, and this reversed the attenuation from neutralization or depletion of IL-1β, neutrophils, or SpeB. Collectively our results suggest that SpeB is essential to activate an IL-1β driven neutrophil response. Unlike during invasive tissue infections, this is beneficial in the upper respiratory tract by disrupting colonization resistance mediated by the microbiota. This provides experimental evidence that the notable inflammation of strep throat, which presents with significant swelling, pain, and neutrophil influx, is not an ineffectual immune response, but rather is a GAS-directed remodeling of this niche for its pathogenic benefit.

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Section: Methodsmentioning

confidence: 99%

Group A Streptococcus Infection of the Nasopharynx Requires Proinflammatory Signaling through the Interleukin-1 Receptor

et al. 2020

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“…Because the LasB protease plays key pathogenic roles during P. aeruginosa infection, the enzyme is one of the potential therapeutic targets for mitigation of the pseudomonal disease severity [ 24 , 25 , 26 ]. Previous data have shown that rabbits infected with a Δ las B mutant strain displayed decreased severity of P. aeruginosa -mediated corneal ulceration [ 27 ].…”

Section: Introductionmentioning

confidence: 99%

Human Single-Chain Antibodies That Neutralize Elastolytic Activity of Pseudomonas aeruginosa LasB

et al. 2021

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LasB (elastase/pseudolysin) is an injurious zinc-metalloprotease secreted by the infecting Pseudomonas aeruginosa. LasB is recognized as the bacterial key virulence factor for establishment of successful infection, acquisition of nutrients, dissemination, tissue invasion, and immune modulation and evasion. LasB digests a variety of the host tissue proteins, extracellular matrices, as well as components of both innate and adaptive immune systems, including immunoglobulins, complement proteins, and cytokines. Thus, this enzyme is an attractive target for disarming the P. aeruginosa. This study generated human single-chain antibodies (HuscFvs) that can neutralize the elastolytic activity of native LasB by using phage display technology. Gene sequences coding HuscFvs (huscfvs) isolated from HuscFv-displaying phage clones that bound to enzymatically active LasB were sub-cloned to expression plasmids for large scale production of the recombinant HuscFvs by the huscfv-plasmid transformed Escherichia coli. HuscFvs of two transformed E. coli clones, i.e., HuscFv-N42 and HuscFv-N45, neutralized the LasB elastolytic activities in vitro. Computer simulation by homology modeling and molecular docking demonstrated that antibodies presumptively formed contact interfaces with the LasB residues critical for the catalytic activity. Although the LasB neutralizing mechanisms await elucidation by laboratory experiments, the HuscFvs should be tested further towards the clinical application as a novel adjunctive therapeutics to mitigate severity of the diseases caused by P. aeruginosa.

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Group A Streptococcus Infection of the Nasopharynx Requires Proinflammatory Signaling Through the Interleukin-1 Receptor

LaRock

Russell

Johnson

et al. 2020

Preprint

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22Group A Streptococcus (GAS) is the etiologic agent of numerous high morbidity and high 23 mortality diseases which commonly have a highly proinflammatory pathology. One factor 24 contributing to this inflammation is the GAS protease SpeB, which directly activates the 25 proinflammatory cytokine interleukin-1β (IL-1β), independent of the canonical inflammasome 26 pathway. IL-1β drives neutrophil activation and recruitment that limits bacterial growth and 27 invasion during invasive skin and soft tissue infections like necrotizing fasciitis. GAS also causes 28 pharyngitis (strep throat), and the upper respiratory tract is its primary nidus for growth and 29 transmission. Since the fitness selection for the species is likely primarily for this site, we 30 examined the process of IL-1β activation in the murine nasopharynx. SpeB still activated IL-1β, 31 which was required for neutrophil migration, but this inflammation instead increased GAS 32 replication. Inhibiting IL-1β or depleting neutrophils, which both promote invasive infection, 33 prevented GAS infection of the nasopharynx. Prior antibiotic exposure increased GAS growth in 34 the murine nasopharynx, and antibiotics were sufficient to reverse the attenuation previously 35 observed when IL-1β, neutrophils, or SpeB were not present to drive inflammation. Therefore, 36 the same fundamental mechanism has opposing effects on virulence at different body sites. 37 Invasive disease may be limited in part due to specific adaptations for inducing host 38 inflammation that are beneficial for pharyngitis. 39 IMPORTANCE 40Our previous reports showed that Group A Streptococcus (GAS) protease SpeB directly activates 41 the host proinflammatory cytokine IL-1β and this restricts invasive skin infection. The upper 42 respiratory tract is the primary site of GAS colonization and infection, but the host-pathogen 43 interactions at this site are still largely unknown. We provide the first evidence that IL-1β-44 3 mediated inflammation promotes upper respiratory tract infection. This provides experimental 45 evidence that the notable inflammation of strep throat, which presents with significant swelling, 46 pain, and neutrophil influx, is not an ineffectual immune response, but rather is a GAS-directed 47 remodeling of this niche for its pathogenic benefit. 48 49 50 Group A Streptococcus (GAS, Streptococcus pyogenes) is a top cause of infectious mortality and 51 responsible for over half a million annual deaths (1). Death is primarily due to invasive diseases, 52 including sepsis, necrotizing fasciitis, and toxic shock syndrome, or autoimmune diseases, most 53 prominently acute rheumatic fever and rheumatic heart disease. The nasopharyngeal mucosa and 54 associated lymphoid tissues is the most common site for infection (strep throat pharyngitis) and 55 the primary carriage site for dissemination of GAS between individuals and to other sites of the 56 body (2). Humans are transiently colonized by GAS throughout childhood but can be culture-57 positive at any point in ...

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Role of Inflammasome-independent Activation of IL-1β by thePseudomonas aeruginosaProtease LasB

Cited by 3 publications

References 53 publications

Group A Streptococcus Infection of the Nasopharynx Requires Proinflammatory Signaling through the Interleukin-1 Receptor

Group A Streptococcus Infection of the Nasopharynx Requires Proinflammatory Signaling through the Interleukin-1 Receptor

Human Single-Chain Antibodies That Neutralize Elastolytic Activity of Pseudomonas aeruginosa LasB

Group A Streptococcus Infection of the Nasopharynx Requires Proinflammatory Signaling Through the Interleukin-1 Receptor

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