Increased Resistance to Intradermal Francisella tularensis LVS Infection by Inactivation of the Sts Phosphatases

Parashar, Kaustubh; Kopping, Erik; Frank, David; Sampath, Vinaya; Thanassi, David G.; Carpino, Nick

doi:10.1128/iai.00406-17

Cited by 11 publications

(19 citation statements)

References 42 publications

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“…4D) at 48 h postinfection. Mice infected with F. novicida by MNA intradermal delivery presented a typical splenic cellular response consistent with tularemia; the infiltration of monocytes and neutrophils without the expansion of T cells led to a relative percentage shift similar to that expected with other Francisella infection models and routes (35)(36)(37).…”

Section: Resultssupporting

confidence: 62%

In Vivo Intradermal Delivery of Bacteria by Using Microneedle Arrays

et al. 2018

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Infectious diseases propagated by arthropod vectors, such as tularemia, are commonly initiated via dermal infection of the skin. However, due to the technical difficulties in achieving accurate and reproducible dermal deposition, intradermal models are less commonly used. To overcome these limitations, we used microneedle arrays (MNAs), which are micron-scale polymeric structures, to temporarily disrupt the barrier function of the skin and deliver a bacterial inoculum directly to the dermis of an animal. MNAs increase reliability by eliminating leakage of the inoculum or blood from the injection site, thereby providing a biologically relevant model for arthropod-initiated disease. Here, we validate the use of MNAs as a means to induce intradermal infection using a murine model of tularemia initiated by We demonstrate targeted delivery of the MNA bolus to the dermal layer of the skin, which subsequently led to innate immune cell infiltration. Additionally,-coated MNAs were used to achieve lethality in a dose-dependent manner in C57BL/6 mice. The immune profile of infected mice mirrored that of established infection models, consisting of markedly increased serum levels of interleukin-6 and keratinocyte chemoattractant, splenic T-cell depletion, and an increase in splenic granulocytes, together confirming that MNAs can be used to reproducibly induce tularemia-like pathogenesis in mice. When MNAs were used to immunize mice using an attenuated mutant ( Δ), all immunized mice survived a lethal subcutaneous challenge. Thus, MNAs can be used to effectively deliver viable bacteria and provide a novel avenue to study intradermally induced microbial diseases in animal models.

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Section: Resultssupporting

confidence: 62%

In Vivo Intradermal Delivery of Bacteria by Using Microneedle Arrays

et al. 2018

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“…The lessons learned from studies with mice that are resistant to C. albicans will likely have significance for optimizing the immune response to other pathogens. In this regard it is interesting that Sts − / − mice are also resistant to infection by the bacterial pathogen Franciscella tularensis (Parashar et al, 2017 ). Finding new ways to selectively boost immune function will be particularly important for types of infections that are characterized by excessive inflammatory damage.…”

Section: Discussionmentioning

confidence: 99%

“…Analogous to the heightened activation seen in T cells lacking Sts expression, one likely scenario is that innate immune cells lacking Sts expression respond to microbial challenge more actively and effectively, allowing them to overcome infection more readily. Support for this model comes from the recent observation that Sts − / − monocytes restrict the intracellular-replicating bacterial pathogen Francisella tularensis LVS with 10-fold greater efficiency than wild type monocytes, thereby enhancing host survival following a lethal infectious dose (Parashar et al, 2017 ). It remains to be determined whether the same mechanism responsible for enhanced Francisella clearance is also responsible for optimal fungal clearance during C. albicans systemic infection.…”

Section: Mutant Mice That Display Resistance To C Albicansmentioning

confidence: 99%

Modulating Host Signaling Pathways to Promote Resistance to Infection by Candida albicans

Carpino

Naseem

Frank

et al. 2017

Front. Cell. Infect. Microbiol.

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Candida albicans is a common human fungal pathogen capable of causing serious systemic infections that can progress to become lethal. Current therapeutic approaches have limited effectiveness, especially once a systemic infection is established, in part due to the lack of an effective immune response. Boosting the immune response to C. albicans has been the goal of immunotherapy, but it has to be done selectively to prevent deleterious hyperinflammation (sepsis). Although an efficient inflammatory response is necessary to fight infection, the typical response to C. albicans results in collateral damage to tissues thereby exacerbating the pathological effects of infection. For this reason, identifying specific ways of modulating the immune system holds promise for development of new improved therapeutic approaches. This review will focus on recent studies that provide insight using mutant strains of mice that are more resistant to bloodstream infection by C. albicans. These mice are deficient in signal transduction proteins including the Jnk1 MAP kinase, the Cbl-b E3 ubiquitin ligase, or the Sts phosphatases. Interestingly, the mutant mice display a different response to C. albicans that results in faster clearance of infection without hyper-inflammation and collateral damage. A common underlying theme between the resistant mouse strains is loss of negative regulatory proteins that are known to restrain activation of cell surface receptor-initiated signaling cascades. Understanding the cellular and molecular mechanisms that promote resistance to C. albicans in mice will help to identify new approaches for improving antifungal therapy.

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“…BMMs that are mobilized in response to bacterial infections within peripheral tissues are known to be potent inducers of pro-inflammatory interferons (eg, IFNγ), as well as additional cytokines and chemokines such as IL-1, IL-18, Ccl3, Cxcl9, and others. 32,33 Because monocytes lacking Sts expression display increased bactericidal activity toward internalized F. tularensis LVS ex vivo, 29 we examined whether cytokine production was deregulated. We infected wild type and Sts −/− BMMs ex vivo with LVS, and evaluated supernatant cytokine levels 24 hours postinfection.…”

Section: Increased Ifnγ Produced By F Tularensis Lvs-infected Sts mentioning

confidence: 99%

“…3.2 | Role of IFNγ in potentiating responses of BMMs to intracellular F. tularensis LVSPreviously, we demonstrated that Sts −/− BMMs restrict intracellular F. tularensis LVS with greater efficiency than wild type cells 29. To investigate a functional role for IFNγ during ex vivo monocyte responses, we cultured infected monocytes in the presence of exogenous IFNγ.…”

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confidence: 99%

A role for the Sts phosphatases in negatively regulating IFNγ‐mediated production of nitric oxide in monocytes

Parashar

Carpino

2020

Immunity Inflam & Disease

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Introduction The atypical Sts phosphatases negatively regulate signaling pathways in diverse immune cell types, with two of their molecular targets being the related kinases Syk and Zap‐70. Mice lacking Sts expression (Sts−/−) are resistant to infection by the live vaccine strain (LVS) of Francisella tularensis. Although the mechanisms underlying the enhanced resistance of Sts−/− mice have not been definitively established, Sts−/− bone marrow‐derived monocytes (BMMs) demonstrate greater clearance of intracellular LVS following ex vivo infection, relative to wild type cells. To determine how the Sts proteins regulate monocyte bactericidal properties, we analyzed responses of infected cells. Methods Monocyte bacterial clearance was assayed using ex vivo coculture infections followed by colony‐forming unit analysis of intracellular bacteria. Levels of gene expression were quantified by quantitative reverse‐transcription polymerase chain reaction, levels of Nos2 protein levels were quantified by Western blot analysis, and levels of nitric oxide (NO) were quantified directly using the Griess reagent. We characterized monocyte cytokine production via enzyme‐linked immunosorbent assay. Results We demonstrate that Sts−/− monocyte cultures produce elevated levels of interferon‐γ (IFNγ) after infection, relative to wild type cultures. Sts−/− monocytes also demonstrate heightened responsiveness to IFNγ. Specifically, Sts−/− monocytes produce elevated levels of antimicrobial NO following IFNγ stimulation, and this NO plays an important role in LVS restriction. Additional IFNγ‐stimulated genes, including Ip10 and members of the Gbp gene family, also display heightened upregulation in Sts−/− cells. Both Sts‐1 and Sts‐2 contribute to the regulation of NO production, as evidenced by the responses of monocytes lacking each phosphatase individually. Finally, we demonstrate that the elevated production of IFNγ‐induced NO in Sts−/− monocytes is abrogated following chemical inhibition of Syk kinase. Conclusion Our results indicate a novel role for the Sts enzymes in regulating monocyte antibacterial responses downstream of IFNγ.

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Increased Resistance to Intradermal Francisella tularensis LVS Infection by Inactivation of the Sts Phosphatases

Cited by 11 publications

References 42 publications

In Vivo Intradermal Delivery of Bacteria by Using Microneedle Arrays

In Vivo Intradermal Delivery of Bacteria by Using Microneedle Arrays

Modulating Host Signaling Pathways to Promote Resistance to Infection by Candida albicans

A role for the Sts phosphatases in negatively regulating IFNγ‐mediated production of nitric oxide in monocytes

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