Project description:Chronic obstructive pulmonary disease (COPD) is the third leading cause of death worldwide. The primary causes of COPD are environmental, including cigarette smoking; however, genetic susceptibility also contributes to COPD risk. Genome-Wide Association Studies (GWASes) have revealed more than 80 genetic loci associated with COPD, leading to the identification of multiple COPD GWAS genes. However, the biological relationships between the identified COPD susceptibility genes are largely unknown. Genes associated with a complex disease are often in close network proximity, i.e. their protein products often interact directly with each other and/or similar proteins. In this study, we use affinity purification mass spectrometry (AP-MS) to identify protein interactions with HHIP, a well-established COPD GWAS gene which is part of the sonic hedgehog pathway, in two disease-relevant lung cell lines (IMR90 and 16HBE). To better understand the network neighborhood of HHIP, its proximity to the protein products of other COPD GWAS genes, and its functional role in COPD pathogenesis, we create HUBRIS, a protein-protein interaction network compiled from 8 publicly available databases. We identified both common and cell type-specific protein-protein interactors of HHIP. We find that our newly identified interactions shorten the network distance between HHIP and the protein products of several COPD GWAS genes, including DSP, MFAP2, TET2, and FBLN5. These new shorter paths include proteins that are encoded by genes involved in extracellular matrix and tissue organization. We found and validated interactions to proteins that provide new insights into COPD pathobiology, including CAVIN1 (IMR90) and TP53 (16HBE). The newly discovered HHIP interactions with CAVIN1 and TP53 implicate HHIP in response to oxidative stress.
Project description:Affinity purification mass spectrometry (AP-MS) was performed to identify protein interactions with HHIP, a well-established COPD GWAS gene. HA-immunoprecipitations (n = 3) were conducted using IMR90 and 16HBE cell lines stably expressing HA-tagged HHIP.
Project description:Chronic obstructive pulmonary disease (COPD) is characterized by persistent and amplified inflammation to cigarette smoke in vulnerable subjects. The genetic risk of persistent inflammation is poorly understood. A mouse model targeting hedgehog interacting protein (HHIP)(Hhip+--), a genetic risk factor for COPD, displays progressive, persistent inflammation resembling human cases, providing a valuable model to study the contribution of the genetic risk factor HHIP to inflammation in COPD. By single cell RNA sequencing of Hhip+-- lungs at different disease stages, we identified induction of IFN-gamma in activated CD8+T cells possibly driving the inflammatory phenotype in Hhip+-- lungs. Hhip expression was restricted to lung fibroblasts, which interaction with CD8+T cells were mediated by increased levels of IL-18 from Hhip+-- fibroblasts. Our finding provides insight into how a common genetic variation contributes to the amplified lymphocytic inflammation in COPD.
Project description:BACKGROUND: The HHIP gene, encoding Hedgehog interacting protein, has been implicated in chronic obstructive pulmonary disease (COPD) by genome-wide association studies (GWAS), and our subsequent studies identified a functional upstream genetic variant that decreased HHIP transcription. However, little is known about how HHIP contributes to COPD pathogenesis. METHODS: Here, we exposed Hhip haploinsufficient mice (Hhip+/-) to cigarette smoke (CS) for 6 months to model the biological consequences caused by CS in human COPD risk-allele carriers at the HHIP locus. Gene expression profiling in murine lungs was performed followed by an integrative network inference analysis, PANDA (Passing Attributes between Networks for Data Assimilation) analysis. RESULTS: We detected more severe airspace enlargement in Hhip+/- mice vs. wild-type littermates (Hhip+/+) exposed to CS. Gene expression profiling in murine lungs suggested enhanced lymphocyte activation pathways in CS-exposed Hhip+/- vs. Hhip+/+ mice, which was supported by increased numbers of lymphoid aggregates and enhanced activation of CD8+ T cells after CS-exposure in the lungs of Hhip+/- mice compared to Hhip+/+ mice. Mechanistically, results from PANDA network analysis suggested a rewired and dampened Klf4 signaling network in Hhip+/- mice after CS exposure. CONCLUSIONS: In summary, HHIP haploinsufficiency exaggerated CS-induced airspace enlargement, which models CS-induced emphysema in human smokers carrying COPD risk alleles at the HHIP locus. Network modeling suggested rewired lymphocyte activation signaling circuits in the HHIP haploinsufficiency state. Total RNA was obtained from the lung tissue of C57BL/6J mice exposed to cigarette smoke (CS) or filtered air (air) for 6 months. Six mice from each of four groups with different genotypes (Hhip+/+ or Hhip+/-) and treatments (air or CS) were randomly chosen for gene expression profiling
Project description:Although cigarette smoke (CS) is the primary risk factor for COPD, the underlying molecular mechanisms for the significant variability in developing COPD in response to CS are incompletely understood. We performed lung gene expression profiling of two different wild-type murine strains (C57BL/6J, NZW/LacJ) and two genetic models with mutations in COPD GWAS genes (HHIP, FAM13A) after 6 months of chronic CS exposure and compared the results to human COPD lung tissues. We identified gene response patterns that correlate with severity of emphysema in mouse and human lungs. Xenobiotic metabolism and Nrf2-mediated oxidative stress response were commonly regulated molecular response patterns across C57BL/6J, Hhip +/- and Fam13a -/- murine models upon chronic CS exposure and human COPD subjects. The CS resistant Fam13a -/- mouse and NZW/LacJ strain revealed an opposite pattern of gene expression response, suggesting distinct molecular pathways for resistance against emphysema. There were few genes commonly modulated between mouse and humans. Our study suggests gene expression responses to CS may be largely species and model dependent, yet shared pathways could provide biologically significant insights underlying individual susceptibility to CS
Project description:BACKGROUND: The HHIP gene, encoding Hedgehog interacting protein, has been implicated in chronic obstructive pulmonary disease (COPD) by genome-wide association studies (GWAS), and our subsequent studies identified a functional upstream genetic variant that decreased HHIP transcription. However, little is known about how HHIP contributes to COPD pathogenesis. METHODS: Here, we exposed Hhip haploinsufficient mice (Hhip+/-) to cigarette smoke (CS) for 6 months to model the biological consequences caused by CS in human COPD risk-allele carriers at the HHIP locus. Gene expression profiling in murine lungs was performed followed by an integrative network inference analysis, PANDA (Passing Attributes between Networks for Data Assimilation) analysis. RESULTS: We detected more severe airspace enlargement in Hhip+/- mice vs. wild-type littermates (Hhip+/+) exposed to CS. Gene expression profiling in murine lungs suggested enhanced lymphocyte activation pathways in CS-exposed Hhip+/- vs. Hhip+/+ mice, which was supported by increased numbers of lymphoid aggregates and enhanced activation of CD8+ T cells after CS-exposure in the lungs of Hhip+/- mice compared to Hhip+/+ mice. Mechanistically, results from PANDA network analysis suggested a rewired and dampened Klf4 signaling network in Hhip+/- mice after CS exposure. CONCLUSIONS: In summary, HHIP haploinsufficiency exaggerated CS-induced airspace enlargement, which models CS-induced emphysema in human smokers carrying COPD risk alleles at the HHIP locus. Network modeling suggested rewired lymphocyte activation signaling circuits in the HHIP haploinsufficiency state.
Project description:Background: When exposed to specific stimuli, macrophages exhibit distinct activation programs, M1 and M2 polarization, that define macrophage function as inflammatory/immune effectors or anti-inflammatory/tissue remodeling cells, respectively. Due to their position on the lung epithelial surface, alveolar macrophages (AM) directly interact with environmental stimuli such as cigarette smoke, the major risk factor for the development of chronic obstructive pulmonary disease (COPD). Based on the current paradigm that, in response to smoking, AM contribute to both inflammatory and tissue remodeling processes in the lung relevant to the pathogenesis of COPD, we hypothesized that chronic exposure to cigarette smoking activates both the M1 and M2 polarization programs in AM. Methods and Findings: To assess this hypothesis, global transcriptional profiling with TaqMan confirmation and flow cytometry analysis was carried out on AM obtained by bronchoalveolar lavage of 24 healthy nonsmokers, 34 healthy smokers and 12 smokers with COPD to assess the expression of 41 M1 genes and 32 M2 genes in each group. Contrary to our expectations, while there was up-regulation of some genes typical for M2-related phenotypes, AM of healthy smokers exhibited substantial suppression of M1-related inflammatory/immune genes. These M1- and M2-related changes progressed with the development of smoking-induced lung disease, with AM of smokers with COPD exhibiting further down-regulation of M1-related genes accompanied with further up-regulation of some M2-related genes. Conclusion: The data demonstrates that the modifications of the AM transcriptome associated with smoking result in a unique phenotype characterized by reprogramming of AM towards M1-deactivated partially M2-polarized macrophages and suggests that, while AM likely contribute to smoking-induced tissue remodeling, the role of AM in the early pathogenesis of smoking-induced COPD in humans is not inflammatory. This concept is a departure from the conventional concept that AM-mediated inflammation participates in the early derangements of the lung induced by smoking, and suggests a novel paradigm for conceptualizing COPD and developing new approaches to prevent the development of smoking-induced lung disease. Comparison of gene expression in alveolar macrophages of normal non-smokers and normal smokers and smokers with COPD
Project description:Activated eosinophils is a major cell type to be mainly involved in allergic diseases. Recent studies also indicated that eosinophils play an important role in the pathogenesis of chronic obstructive pulmonary disease (COPD), especially asthma-COPD overlap and/or eosinophil COPD. The aim of this study is to clarify cellular characters of human eosinophils in patients with asthma-COPD overlap and/or eosinophil COPD.