Project description:Introduction: Sarcoidosis is a multisystem immuno-inflammatory disorder of unknown etiology that most commonly involves the lungs. We hypothesized that an unbiased approach to identify pathways activated in alveolar macrophagesâa key immuno-inflammatory cell in the lungâcan shed light on the pathogenesis of this complex disease. Methods: We recruited 15 patients with various stages of sarcoidosis and 12 healthy controls. All subjects underwent bronchoscopy with lavage. For each subject, total RNA was extracted from bronchoalveolar (BAL) cells and hybridized to an Affymetrix GeneChip Human Genome U133A 2.0 microarray. Rigorous statistical methods were applied to identify differential gene expression between subjects with sarcoidosis vs. controls. To better elucidate pathways differentially activated between these groups, we applied gene set enrichment analysis (GSEA) to the transcriptional profiles of BAL cells. We used false discovery rate (FDR) < 0.01 to designate significant enrichment. Results: Sarcoid patients were either non-smokers or ex-smokers, all had lung involvement and only 2 were on systemic prednisone. Healthy controls were all non-smokers. Comparison of BAL cell gene expression between sarcoidosis and healthy subjects revealed over 1200 differentially expressed genes at an FDR cutoff < 0.01. Several previously described immune mediators, such as interferon gamma, were up-regulated in the sarcoidosis subjects. Since genes often exert their influence through functionally coherent modules, we performed GSEA based on global expression profiles of alveolar macrophages between the subject groups. We identified more than 200 gene sets enriched in patients with sarcoidosis whereas very few pathways were over-represented in the healthy controls. Many of the sarcoidosis-associated pathways mapped to inflammatory and immune-related processes including T-cell signaling, graft vs. host disease, IL-12, IL-23, and IL-17 pathways, and oxidative phosphorylation. However, we also found and confirmed significant alteration in Proteasome-related pathways. Conclusions: BAL cells in sarcoidosis are characterized by enrichment of distinct transcriptional networks involved in immuno-inflammatory and proteasomal processes. Our findings add to the growing evidence implicating airspace resident cells in the pathogenesis of sarcoidoisis and identify specific pathways whose activation may modulate disease progression. Total RNA from BAL cells of 15 subjects with sarcoidosis and 12 healthy controls was hybridized to 27 Affymetrix Genechip Human U133A 2.0 microarrays

Project description:Introduction: Sarcoidosis is a multisystem immuno-inflammatory disorder of unknown etiology that most commonly involves the lungs. We hypothesized that an unbiased approach to identify pathways activated in alveolar macrophages—a key immuno-inflammatory cell in the lung—can shed light on the pathogenesis of this complex disease. Methods: We recruited 15 patients with various stages of sarcoidosis and 12 healthy controls. All subjects underwent bronchoscopy with lavage. For each subject, total RNA was extracted from bronchoalveolar (BAL) cells and hybridized to an Affymetrix GeneChip Human Genome U133A 2.0 microarray. Rigorous statistical methods were applied to identify differential gene expression between subjects with sarcoidosis vs. controls. To better elucidate pathways differentially activated between these groups, we applied gene set enrichment analysis (GSEA) to the transcriptional profiles of BAL cells. We used false discovery rate (FDR) < 0.01 to designate significant enrichment. Results: Sarcoid patients were either non-smokers or ex-smokers, all had lung involvement and only 2 were on systemic prednisone. Healthy controls were all non-smokers. Comparison of BAL cell gene expression between sarcoidosis and healthy subjects revealed over 1200 differentially expressed genes at an FDR cutoff < 0.01. Several previously described immune mediators, such as interferon gamma, were up-regulated in the sarcoidosis subjects. Since genes often exert their influence through functionally coherent modules, we performed GSEA based on global expression profiles of alveolar macrophages between the subject groups. We identified more than 200 gene sets enriched in patients with sarcoidosis whereas very few pathways were over-represented in the healthy controls. Many of the sarcoidosis-associated pathways mapped to inflammatory and immune-related processes including T-cell signaling, graft vs. host disease, IL-12, IL-23, and IL-17 pathways, and oxidative phosphorylation. However, we also found and confirmed significant alteration in Proteasome-related pathways. Conclusions: BAL cells in sarcoidosis are characterized by enrichment of distinct transcriptional networks involved in immuno-inflammatory and proteasomal processes. Our findings add to the growing evidence implicating airspace resident cells in the pathogenesis of sarcoidoisis and identify specific pathways whose activation may modulate disease progression.

Project description:Multi-walled carbon nanotubes (MWCNT) cause lung fibrosis in rodents and exacerbate airway fibrosis in the mouse ovalbumin model of allergic asthma. Interleukin 13 (IL-13) is a key cytokine secreted by T helper type 2 (Th2) cells. IL-13 is up-regulated in human asthma and animal models that activate pro-fibrotic and pro-proliferative cell signaling cascades in human lung fibroblasts (HLF). This study tested the hypothesis that IL-13 alters the gene expression profile of HLF exposed to MWCNT. Carbon black nanoparticles (CBNP) were also compared to MWCNT as they are relatively inert nanoparticles that do not cause fibrosis. Confluent, quiescent cultures of HLF were treated with 10 ng/ml IL-13 or serum-free defined medium (vehicle) for 24 hours prior to treatment with 10 M-BM-5g/cm2 MWCNT or CBNP. At 4, 24, or 48 hours following nanoparticle exposure, total RNA was isolated and gene expression was measured using the Affymetrix Human Genome U133A2.0 Array. The data were analyzed using the JMP Genomics statistical platform. IL-13 and MWCNT each caused changes in the expression of distinct gene subsets over the time-course investigated. The combination of IL-13 and MWCNT resulted in a gene expression profile that was distinct from patterns induced or suppressed by either IL-13 or MWCNT alone. CBNP caused changes in gene expression that were distinct from IL-13 or MWCNT. Interestingly, the combination of IL-13 and MWCNT increased the expression of IL-17A and increased collagen (Col1A1), while MWCNT alone increased interferon-inducible protein-27 (IFI27), suggesting that Th2 microenvironment containing IL-13 shifts MWCNT-induced gene expression from a Th1 to a Th17 gene expression profile. These data provide insight into the mechanisms by which MWCNT alter the biology of fibroblasts during normal and allergic inflammatory conditions. Adult Lung Fibroblasts were treated with 10 M-BM-5g/cm2 MWCNT, CBNP, or vehicle with or without IL-13 for 4 hours, 24 hours, or 48 hours.

Project description:Background: Biological interpretation of gene expression data may differ depending on underlying assumptions and statistical tests used by the chosen bioinformatic tool. We used Gene Set Enrichment Analysis (GSEA) and Ingenuity Pathway Analysis (IPA) to analyze previously generated gene expression profiles induced in human monocytes by N. meningitidis and IL-10 (“the model system”), and by meningococcal sepsis plasma before and after immunodepletion of IL-10 (“the patient plasma system”). The objectives were to compare whether these two methods resulted in similar biological interpretation of the datasets; and identify whether GSEA provided additional insight about the human monocyte host response to meningococcal activation. Results: In both experimental models, GSEA and IPA associated genes induced in monocytes by N. meningitidis with pro-inflammatory innate immune activation, including TNF-signaling, Toll-like receptor signaling, JAK-STAT-signaling, type I and type II interferon. GSEA associated genes regulated by the presence of IL-10 with similar gene sets in both the model system and the patient plasma system. In the model system, GSEA and IPA identified 170 genes associated with oxidative phosphorylation/mitochondrial function to be down-regulated in monocytes stimulated with meningococci. In the patient plasma system, GSEA and IPA combined identified 122 genes associated with oxidative phosphorylation/mitochondrial dysfunction to be down-regulated by meningococcal sepsis plasma depleted for IL-10. Combining analyses from GSEA and IPA identified that some genes associated with oxidative phosphorylation/mitochondrial function that were inhibited by N. meningitidis were partially up-regulated by IL-10. Conclusions: Biological processes associated with the gene expression changes in the model system of meningococcal sepsis was comparable to the results found in the patient plasma system. By combining GSEA with IPA, we have discovered an inhibitory effect exerted by N. meningitidis on genes associated with oxidative phosphorylation, and that IL-10 possibly partially dampen this strong inhibitory effect, thereby identifying, to our knowledge, yet another area where IL-10 regulates the effect of LPS. We suggest that relying on a single bioinformatic tool together with arbitrarily chosen filtering criteria for data analysis may result in overlooking relevant biological processes and signaling pathways associated with genes differentially expressed between compared experimental conditions.

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Transcriptional Survey of Alveolar Macrophages in a Murine Model of Chronic Granulomatous Inflammation Reveals Common Themes with Human Sarcoidosis

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