Dataset Information

Effect of mannose-binding lectin (MBL) on pulmonary gene expression in response to ozone

ABSTRACT: 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.

ORGANISM(S): Mus musculus

PROVIDER: GSE68522 | GEO | 2016/04/25

SECONDARY ACCESSION(S): PRJNA282970

REPOSITORIES: GEO

ACCESS DATA

Similar Datasets

Project description:Background: The mechanisms underlying ozone (O3)-induced pulmonary inflammation remain unclear. Interleukin (IL)-10 is an anti-inflammatory cytokine that is known to inhibit inflammatory mediators. Objectives: The current study investigated the molecular mechanisms underlying IL-10-mediated attenuation of O3-induced pulmonary inflammation in mice. Methods: Il10-deficient (Il10-/-) and wild type (Il10+/+) mice were exposed to 0.3-ppm O3 or filtered air for 24, 48 or 72 hr. Immediately following exposure, differential cell counts, and total protein (a marker of lung permeability) were assessed from bronchoalveolar lavage fluid (BALF). mRNA and protein levels of cellular mediators were determined from lung homogenates. We also utilized global mRNA expression analyses of lung tissue with Ingenuity Pathway Analyses (IPA) to identify patterns of gene expression through which IL-10 modifies O3-induced inflammation. Results: Mean numbers of BALF polymorphonuclear leukocytes (PMNs) were significantly greater in Il10-/- mice than in Il10+/+ mice after exposure to O3 at all time points tested. O3-enhanced nuclear NF-kB translocation was elevated in the lungs of Il10-/- compared to Il10+/+ mice. Gene expression analyses revealed several key IL-10 and O3-dependent mediators, including IL-6, MIP-2, IL-1 and CD86. Conclusions: Results indicated that IL-10 protects against O3-induced pulmonary neutrophilic inflammation and cell proliferation. Moreover, gene expression analyses identified three response pathways and several novel genetic targets (e.g. Ccr1, Socs3, Il33, Hat1, and Gale) through which IL10 may modulate the innate and adaptive immune response. These novel mechanisms of protection against the pathogenesis of O3-induced pulmonary inflammation may also provide potential therapeutic targets to protect susceptible individuals. PARALLEL study design with 26 samples. Biological replicates: 2 to 3 replicates per group with wild type air exposed animals as controls for each time point (24, 48, 72 hours). Time-Course, Dose-Response, Strain comparison

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:Toll like receptor 4 (TLR4), an innate immunity gene, is involved in responses to several pulmonary agonists including endotoxin (LPS; Poltorak et al.,1998), ozone (O3 ,Kleeberger et. al., 2001), Pseudomonas aeruginosa (Faure et al, 2004), and hyperoxia (Zhang et al, 2005). TLR4 appears to partially mediate the response to LPS- and O3-induced lung injury, however, TLR4 is protective for prevention of injury in Pseudomonas aeruginosa infection and against acute lung injury (hyperoxia). The mechanism behind this protection is unclear. We previously demonstrated that TLR4 was also protective against BHT-induced chronic inflammation and tumor promotion (Bauer et al, 2005). C.C3H-Tlr4Lps-d (BALBLps-d) mice, congenic for a 10 cM region of C3H/HeJ chromosome 4 that contains Tlr4 (Vogel et al, 1994), have a missence mutation that renders TLR4 dysfunctional. The Tlr4 mutation likely abrogates signaling by disrupting a direct point of contact with other signaling molecules (Akira S, Takeda K. Toll-like receptor signalling. Nat Rev Immunol 2004;4(7):499-511.). Bronchoalveolar lavage fluid (BALF) alveolar macrophages, lymphocytes, and total protein content were significantly elevated in BALBLps-d mice compared to BALB/c (BALB; Tlr4 sufficient) mice following chronic BHT (Bauer et al., 2005). BALBLps-d mice also had a significant increase in tumor multiplicity (60%) over that of BALB mice in response to an MCA/BHT tumor promotion protocol. While this was the first model to demonstrate a protective role for TLR4 in chronic lung inflammation and tumorigenesis, the downstream mechanism regulating this protective response remains unknown. Using Affymetrix microarray analysis followed by GeneSpring and Ingenuity pathway analyses, we herein identified known and novel downstream pathways and their interactions that may be involved in the protective mechanism elicited by TLR4. We therefore hypothesize that these pathways and interactions amongst the genes identified during the tumor promotion/chronic inflammation stage are in part influencing the differential strain response observed during tumorigenesis. Keywords: time course, tumor study Protocol 1 - 3 biological replicates after chronic dosing in each mouse strain Protocol 2 - multiple replicates after MCA/BHT tumor progression model used

Dataset Information

Effect of mannose-binding lectin (MBL) on pulmonary gene expression in response to ozone

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure