71 research outputs found
ILâ17A deficiency mitigates bleomycinâinduced complement activation during lung fibrosis
Interleukin 17A (ILâ17A) and complement (Câ˛) activation have each been implicated in the pathogenesis of idiopathic pulmonary fibrosis (IPF). We have reported that ILâ17A induces epithelial injury via TGFâβ in murine bronchiolitis obliterans; that TGFâβ and the CⲠcascade present signaling interactions in mediating epithelial injury; and that the blockade of CⲠreceptors mitigates lung fibrosis. In the present study, we investigated the role of ILâ17A in regulating CⲠin lung fibrosis. Microarray analyses of mRNA isolated from primary normal human small airway epithelial cells indicated that ILâ17A (100 ng/ml; 24 h; n = 5 donor lungs) induces CⲠcomponents (CⲠfactor B, C3, and GPCR kinase isoform 5), cytokines (IL8, â6, and â1B), and cytokine ligands (CXCL1, â2, â3, â5, â6, and â16). ILâ17A induces protein and mRNA regulation of CⲠcomponents and the synthesis of active CⲠ3a (C3a) in normal primary human alveolar type II epithelial cells (AECs). Wildâtype mice subjected to ILâ17A neutralization and ILâ17A knockout (i717aâ/â) mice were protected against bleomycin (BLEO)âinduced fibrosis and collagen deposition. Further, BLEOâinjured i17aâ/â mice had diminished levels of circulating Krebs Von Den Lungen 6 (alveolar epithelial injury marker), local caspaseâ3/7, and local endoplasmic reticular stressârelated genes. BLEOâinduced local CⲠactivation [C3a, C5a, and terminal CⲠcomplex (C5bâ9)] was attenuated in il17aâ/â mice, and ILâ17A neutralization prevented the loss of epithelial CⲠinhibitors (CⲠreceptorâ1 related isoform Y and decay accelerating factor), and an increase in local TUNEL levels. RNAiâmediated gene silencing of il17a in fibrotic mice arrested the progression of lung fibrosis, attenuated cellular apoptosis (caspaseâ3/7) and lung deposition of collagen and CⲠ(C5bâ9). Compared to normals, plasma from IPF patients showed significantly higher hemolytic activity. Our findings demonstrate that limiting complement activation by neutralizing ILâ17A is a potential mechanism in ameliorating lung fibrosis.âCipolla, E., Fisher, A. J., Gu, H., Mickler, E. A., Agarwal, M., Wilke, C. A., Kim, K. K., Moore, B. B., Vittal, R. ILâ17A deficiency mitigates bleomycinâinduced complement activation during lung fibrosis. FASEB J. 31, 5543â5556 (2017). www.fasebj.orgPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154482/1/fsb2fj201700289r-sup-0001.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154482/2/fsb2fj201700289r.pd
Alveolar macrophage- derived extracellular vesicles inhibit endosomal fusion of influenza virus
Alveolar macrophages (AMs) and epithelial cells (ECs) are the lone resident lung cells positioned to respond to pathogens at early stages of infection. Extracellular vesicles (EVs) are important vectors of paracrine signaling implicated in a range of (patho)physiologic contexts. Here we demonstrate that AMs, but not ECs, constitutively secrete paracrine activity localized to EVs which inhibits influenza infection of ECs inĂÂ vitro and inĂÂ vivo. AMs exposed to cigarette smoke extract lost the inhibitory activity of their secreted EVs. Influenza strains varied in their susceptibility to inhibition by AM- EVs. Only those exhibiting early endosomal escape and high pH of fusion were inhibited via a reduction in endosomal pH. By contrast, strains exhibiting later endosomal escape and lower fusion pH proved resistant to inhibition. These results extend our understanding of how resident AMs participate in host defense and have broader implications in the defense and treatment of pathogens internalized within endosomes.SynopsisExtracellular vesicles are emerging as homeostatic vectors, but poorly understood in influenza infection. Here, alveolar macrophage- derived extracellular vesicles inhibit influenza- endosome fusion in a strain- specific, and pH- dependent manner.Following initial infection of epithelial cells, the influenza virus traffics within host cell endosomes which undergo progressive acidification.Prior to gaining entry into the nucleus for its replication, influenza virus must fuse with endosome membranes- an event initiated at a strain- specific pH.Alveolar macrophages secrete extracellular vesicles which, when internalized by epithelial cells, lead to accelerated acidification of endosomes.Infection of epithelial cells by influenza strains which preferentially fuse with endosome membranes at high pH is inhibited by extracellular vesicles. Infection by influenza strains which fuse at low pH is unaffected by extracellular vesicles.Extracellular vesicles secreted from alveolar macrophages can promote acidification of endosomes in influenza virus- infected epithelial cells to inhibit viral replication.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156477/5/embj2020105057-sup-0002-EVFigs.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156477/4/embj2020105057_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156477/3/embj2020105057.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156477/2/embj2020105057-sup-0001-Appendix.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156477/1/embj2020105057.reviewer_comments.pd
Cataract research using electronic health records
<p>Abstract</p> <p>Background</p> <p>The eMERGE (electronic MEdical Records and Genomics) network, funded by the National Human Genome Research Institute, is a national consortium formed to develop, disseminate, and apply approaches to research that combine DNA biorepositories with electronic health record (EHR) systems for large-scale, high-throughput genetic research. Marshfield Clinic is one of five sites in the eMERGE network and primarily studied: 1) age-related cataract and 2) HDL-cholesterol levels. The purpose of this paper is to describe the approach to electronic evaluation of the epidemiology of cataract using the EHR for a large biobank and to assess previously identified epidemiologic risk factors in cases identified by electronic algorithms.</p> <p>Methods</p> <p>Electronic algorithms were used to select individuals with cataracts in the Personalized Medicine Research Project database. These were analyzed for cataract prevalence, age at cataract, and previously identified risk factors.</p> <p>Results</p> <p>Cataract diagnoses and surgeries, though not type of cataract, were successfully identified using electronic algorithms. Age specific prevalence of both cataract (22% compared to 17.2%) and cataract surgery (11% compared to 5.1%) were higher when compared to the Eye Diseases Prevalence Research Group. The risk factors of age, gender, diabetes, and steroid use were confirmed.</p> <p>Conclusions</p> <p>Using electronic health records can be a viable and efficient tool to identify cataracts for research. However, using retrospective data from this source can be confounded by historical limits on data availability, differences in the utilization of healthcare, and changes in exposures over time.</p
TLR9-induced interferon β is associated with protection from gammaherpesvirus-induced exacerbation of lung fibrosis
Abstract
Background
We have shown previously that murine gammaherpesvirus 68 (ÎłHV68) infection exacerbates established pulmonary fibrosis. Because Toll-like receptor (TLR)-9 may be important in controlling the immune response to ÎłHV68 infection, we examined how TLR-9 signaling effects exacerbation of fibrosis in response to viral infection, using models of bleomycin- and fluorescein isothiocyanate-induced pulmonary fibrosis in wild-type (Balb/c) and TLR-9-/- mice.
Results
We found that in the absence of TLR-9 signaling, there was a significant increase in collagen deposition following viral exacerbation of fibrosis. This was not associated with increased viral load in TLR-9-/- mice or with major alterations in T helper (Th)1 and Th2 cytokines. We examined alveolar epithelial-cell apoptosis in both strains, but this could not explain the altered fibrotic outcomes. As expected, TLR-9-/- mice had a defect in the production of interferon (IFN)-β after viral infection. Balb/c fibroblasts infected with γHV68 in vitro produced more IFN-β than did infected TLR-9-/- fibroblasts. Accordingly, in vitro infection of Balb/c fibroblasts resulted in reduced proliferation rates whereas infection of TLR-9-/- fibroblasts did not. Finally, therapeutic administration of CpG oligodeoxynucleotides ameliorated bleomycin-induced fibrosis in wild-type mice.
Conclusions
These results show a protective role for TLR-9 signaling in murine models of lung fibrosis, and highlight differences in the biology of TLR-9 between mice and humans.http://deepblue.lib.umich.edu/bitstream/2027.42/112877/1/13069_2011_Article_57.pd
The Role of CCL12 in the Recruitment of Fibrocytes and Lung Fibrosis
We have previously shown that mice that are genetically deficient in the CCR2 gene (CCR2â/â mice) are protected from fluorescein isothiocyanate (FITC)-induced lung fibrosis. Protection from fibrosis correlated with impaired recruitment of fibrocytes (bone marrowâderived cells, which share both leukocyte and mesenchymal markers). There are three ligands for CCR2 in the mouse: CCL2, CCL7, and CCL12. CCL2 and CCL12 are both elevated in the lung after FITC injury, but with different kinetics. CCL2 is maximal at Day 1 and absent by Day 7 after FITC. In contrast, CCL12 peaks at Day 3, but remains elevated through Day 21 after FITC. We now demonstrate that while CCR2â/â mice are protected from FITC-induced fibrosis, CCL2â/â mice are not. CCL2â/â mice are able to recruit fibrocytes to FITC-injured airspaces, unlike CCR2â/â mice. Adoptive transfer of CCR2-expressing fibrocytes augments FITC-induced fibrosis in both wild-type and CCR2â/â mice, suggesting that these cells play a pathogenic role in the disease process. Both CCL2 and CCL12 are chemotactic for fibrocytes. However, neutralization of CCL12 in wild-type mice significantly protects from FITC-induced fibrosis, whereas neutralization of CCL2 was less effective. Thus, CCL12 is likely the CCR2 ligand responsible for driving fibroproliferation in the mouse. As murine CCL12 is homologous to human CCL2, we suggest that the pathobiology of murine CCL12 in fibroproliferation may correlate to human CCL2 biology
Regulation of Chemokine Production by the Oxidative Metabolism of L-Arginine in a Human Mixed Lymphocyte Reaction
Previous studies have shown that during the development of a mixed lymphocyte reaction (MLR) levels of the chemotactic cytokines IL-8 and MCP-1 (members of the C-X-C and C-C supergene families, respectively) increase in a time-dependent fashion, and that the production of these chemokines correlates with the magnitude of responsiveness to alloantigen (13). Furthermore, the responsiveness to alloantigen in the context of a MLR has been shown to be regulated by the oxidative metabolism of L-arginine (12). We postulated that competitive antagonism of the L-arginine metabolic pathway in a human MLR may alter the production of members of the C-C and C-X-C chemokine families. To test this hypothesis, mononuclear cells were isolated from healthy individuals and subjected to a one-way MLR in the presence or absence of varying concentrations of an L-arginine competitive inhibitor, NG-methyl-L-arginine (NMA: 50 to 500 [mu]M). When the MLR was performed in the presence of NMA (500 [mu]M), the production of IL-8 increased twofold (P P < 0.05), while MCP-1 and MIP-1[alpha] were not significantly altered. These findings suggest that NMA, an inhibitor of the L-arginine metabolic pathway, may regulate the production of specific C-X-C chemokines, IL-8 and ENA-78, during a MLR. In contrast, the production of MCP-1 and MIP-1[alpha], members of the C-C chemokine family, does not appear to be regulated by this inhibitor of the oxidative metabolism of L-arginine in the context of a MLR.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31513/1/0000435.pd
- âŚ