Project description:Rationale: Previous work demonstrated that pre-exposure to ozone primes innate immunity and increases TLR4-mediated response to subsequent stimulation with lipopolysaccharide (LPS). To further explore the pulmonary innate immune response to ozone exposure, we investigated the effect of ozone in combination with Pam3CYS, a synthetic TLR2/TLR1 agonist. Methods: Bronchoalveolar lavage (BAL) and lungs were harvested from C57Bl/6 mice after exposure to ozone or filtered air followed by saline or Pam3CYS 24 hours later. Cells and cytokines in the BAL, surface expression of TLRs on macrophages, and lung RNA genomic expression profiles were examined. Results: We demonstrate an increased BAL cell influx, increased IL-6 and KC, and decreased MIP-1α and TNF-α in response to Pam3CYS as a result of ozone pre-exposure. We also observed increased cell surface expression of TLR4, TLR2 and TLR1 on macrophages as a result of ozone alone or in combination with Pam3CYS. Gene expression analysis of lung tissue revealed a significant increase in expression of genes related to injury repair and cell cycle as a result of ozone exposure. When comparing Pam3CYS treated animals to saline treated animals with or without ozone, genes associated with inflammation were significantly increased. Potentially novel ozone exposure candidate genes (CCK, RELM-α and β) were identified. Conclusion: Our results extend previous findings with ozone/LPS to other TLRs PAMPs and suggest that ozone priming of innate immunity is a general mechanism. Gene expression profiling of lung tissue identified transcriptional networks and genes that contribute to the priming of innate immunity at the molecular level. Mice were exposed to either 2ppm ozone or filtered air (FA) for 3 hours. 24 hours following ozone exposure, mice from either the ozone or FA group were treated intratracheally with either 100ug of Pam3CYS in saline or saline alone. Animals were euthanized 4 or 24 hours post-Pam3CYS exposure. RNA from whole lung tissue from 4 animals per group was profiled.
Project description:Rationale: Previous work demonstrated that pre-exposure to ozone primes innate immunity and increases TLR4-mediated response to subsequent stimulation with lipopolysaccharide (LPS). To further explore the pulmonary innate immune response to ozone exposure, we investigated the effect of ozone in combination with Pam3CYS, a synthetic TLR2/TLR1 agonist. Methods: Bronchoalveolar lavage (BAL) and lungs were harvested from C57Bl/6 mice after exposure to ozone or filtered air followed by saline or Pam3CYS 24 hours later. Cells and cytokines in the BAL, surface expression of TLRs on macrophages, and lung RNA genomic expression profiles were examined. Results: We demonstrate an increased BAL cell influx, increased IL-6 and KC, and decreased MIP-1α and TNF-α in response to Pam3CYS as a result of ozone pre-exposure. We also observed increased cell surface expression of TLR4, TLR2 and TLR1 on macrophages as a result of ozone alone or in combination with Pam3CYS. Gene expression analysis of lung tissue revealed a significant increase in expression of genes related to injury repair and cell cycle as a result of ozone exposure. When comparing Pam3CYS treated animals to saline treated animals with or without ozone, genes associated with inflammation were significantly increased. Potentially novel ozone exposure candidate genes (CCK, RELM-α and β) were identified. Conclusion: Our results extend previous findings with ozone/LPS to other TLRs PAMPs and suggest that ozone priming of innate immunity is a general mechanism. Gene expression profiling of lung tissue identified transcriptional networks and genes that contribute to the priming of innate immunity at the molecular level.
Project description:Ozone is a common pollutant and a potent oxidant in industrialized nations. The mechanisms of ozone-induced lung injury and differential susceptibility are not fully understood. Ozone-induced lung inflammation is mediated, in part, by the innate immune system. We hypothesized that mannose binding lectin (MBL), which has a central role in the activation of the complement pathway of innate immunity, is a necessary component of the pro-inflammatory events caused by ozone-mediated activation of the innate immune system. Wild-type (Mbl+/+) and MBL deficient (Mbl-/-) mice were exposed to ozone (0.3 ppm) for 24, 48, and 72 hours, and bronchoalveolar lavage fluid (BALF) was examined for inflammatory markers. Compared to Mbl+/+ mice, significantly greater mean BALF eosinophils, neutrophils and neutrophil attractants CXCL2 (MIP-2) and CXCL5 (LIX) were found in Mbl-/- mice exposed to ozone. Using genome-wide mRNA microarray analyses, we identified significant differences in expression response profiles and networks at baseline (e.g. NRF2 mediated oxidative stress response) and after exposure (e.g. humoral immune response) between Mbl+/+ and Mbl-/- mice. The microarray data were further analyzed using a pattern recognition analysis for Extracting Patterns and Identifying co-expressed Genes (EPIG), and discovered several informative differential response patterns and subsequent gene sets, including antimicrobial response and inflammatory response. These novel findings demonstrate that targeted deletion of Mbl caused differential expression of inflammation-related gene sets basally and after exposure to ozone, and significantly reduced pulmonary inflammation thus indicating an important innate immunomodulatory role of the gene in this model.
Project description:Cancer immunotherapies targeting the adaptive immune system have revolutionized the treatment for many cancer patients. However, a considerable fraction of patients does not benefit from targeting only the adaptive arm of the immune system. Here, we demonstrate that priming the innate immune system via systemic delivery of a novel synthetic TLR2/6 agonist, AXA-042, represents a rational strategy to boost anti-tumor immunity. TLR2 and TLR6 expression in mouse and human was predominantly confined to tumor-infiltrating myeloid immune cells. Activation of TLR2-signalling induced a pro-inflammatory phenotype in myeloid immune cells with increased cytokine production which resulted in strong T cell dependent anti-tumor immune responses. Systemic delivery of AXA-042 was well tolerated in mouse and non-human primates, demonstrated innate response engagement and anti-tumor efficacy as monotherapy and in combination with checkpoint inhibitors across a wide range of preclinical mouse models. Preclinical efficacy and safety studies provide evidence that priming and re-shaping the innate immune system with the systemic administration of a TLR2 agonist may represent a promising approach for cancer patients. AXA-042 has completed GLP toxicology studies and is currently in clinical development (ACTRN12622000993796) in advanced solid tumors.
Project description:Streptococcus suis is an emerging zoonotic agent causing meningitis and septicemia. Outbreaks in humans in China with atypical cases of streptococcal toxic shock-like syndrome have been described to be caused by a clonal epidemic S. suis strain characterized as sequence type (ST) 7 by multilocus sequence typing, different from the classical ST1 usually isolated in Europe. Previous in vitro studies showed that Toll-like receptor (TLR) 2 plays a major role in S. suis ST1 interactions with host cells. In the present study, the in vivo role of TLR2 in systemic infections caused by S. suis ST1 or ST7 strains using TLR2 deficient (TLR2-/-) mice was evaluated. TLR2-mediated recognition significantly contributes to the acute disease caused by the highly virulent S. suis ST1 strain, since the TLR2-/- mice remained unaffected when compared to wild type (WT) mice. The lack of mortality could not be associated with a lower bacterial burden; however, a significant decrease in the induction of pro-inflammatory mediators, as evaluated by microarray, real-time PCR and protein assays, was observed. On the other hand, TLR2-/- mice infected with the epidemic ST7 strain presented no significant differences regarding survival and expression of pro-inflammatory mediators when compared to the WT mice. Together, these results show a TLR2-independent host innate immune response to S. suis that depends on the strain. Total RNA obtained from spleen of C57BL/6 mice or C57BL/6 TLR2-KO mice infected with Streptococcus suis strain P1/7. Four replicates in both groups.
Project description:Streptococcus suis is an emerging zoonotic agent causing meningitis and septicemia. Outbreaks in humans in China with atypical cases of streptococcal toxic shock-like syndrome have been described to be caused by a clonal epidemic S. suis strain characterized as sequence type (ST) 7 by multilocus sequence typing, different from the classical ST1 usually isolated in Europe. Previous in vitro studies showed that Toll-like receptor (TLR) 2 plays a major role in S. suis ST1 interactions with host cells. In the present study, the in vivo role of TLR2 in systemic infections caused by S. suis ST1 or ST7 strains using TLR2 deficient (TLR2-/-) mice was evaluated. TLR2-mediated recognition significantly contributes to the acute disease caused by the highly virulent S. suis ST1 strain, since the TLR2-/- mice remained unaffected when compared to wild type (WT) mice. The lack of mortality could not be associated with a lower bacterial burden; however, a significant decrease in the induction of pro-inflammatory mediators, as evaluated by microarray, real-time PCR and protein assays, was observed. On the other hand, TLR2-/- mice infected with the epidemic ST7 strain presented no significant differences regarding survival and expression of pro-inflammatory mediators when compared to the WT mice. Together, these results show a TLR2-independent host innate immune response to S. suis that depends on the strain. Total RNA obtained from spleen of C57BL/6 mice or C57BL/6 TLR2-KO mice infected with Streptococcus suis strain SC84. Four replicates in both groups.
Project description:Sepsis caused by Gram-positive bacterial pathogens is a major fatal disease but its molecular basis remains elusive. Toll-like receptor 2 (TLR2) has been implicated in the orchestration of inflammation and sepsis but its role appears to vary for different pathogen species and clones. Accordingly, Staphylococcus aureus clinical isolates differ substantially in their capacity to activate TLR2. Here we show that strong TLR2 stimulation depends on high-level production of phenol-soluble modulin (PSM) peptides in response to the global virulence activator Agr. PSMs are required for mobilizing lipoproteins, the TLR2 agonists, from the staphylococcal cytoplasmic membrane. Notably, the course of sepsis caused by PSM-deficient S. aureus is similar in wild-type and TLR2-deficient mice, but TLR2 is required for protection of mice against PSM-producing S. aureus. Thus, a crucial role of TLR2 depends on agonist release by bacterial surfactants. Modulation of this process may lead to new therapeutic strategies against Gram-positive infections.
Project description:Transcriptome profiles for innate and adaptive immune stimuli important for host response against mycobacteria. Human monocyte-derived macrophages were stimulated with TLR2/1 ligand and interferon-g, stimuli present during innate and adaptive immune responses, respectively.