Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0032285 (pneumonia)
 54,520 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recruitment of neutrophils into alveolar air spaces is an early event in the pathogenesis of pneumonia due to Streptococcus pneumoniae. This results from chemokines released by activated endothelial and epithelial cells and alveolar macrophages. Culture supernatants of 6 wild-type strains of S. pneumoniae, shown to contain choline-binding protein A (CbpA; clades A and B), induced release of chemokine CXCL8 from the human alveolar epithelial cell line A549, whereas a CbpA deletion mutant elicited significantly reduced CXCL8 release, compared with that of its isogenic parent (P<.01). Recombinant CbpA up-regulated expression of messenger RNA of CXCL8 and CCL2 but not of XCL1, CXCL10, CCL1, CCL3, CCL4, or CCL5 in A549 cells and induced increased secretion of CXCL8, CCL2, CXCL1, and CXCL5 in a dose- and time-dependent manner. CbpA also increased the expression of intercellular adhesion molecule 1 (CD54) by A549 cells. Thus, CbpA of S. pneumoniae induces the transcription and release of proinflammatory molecules by human alveolar epithelial cells.
 ...
PMID:Choline-binding protein A of Streptococcus pneumoniae elicits chemokine production and expression of intercellular adhesion molecule 1 (CD54) by human alveolar epithelial cells. 1240 94

Invasive aspergillosis is a severe pneumonia that is usually fatal despite currently available therapy. The disease disproportionately afflicts immunocompromised patients, indicating the critical importance of the immune status of the host in this infection, but the defense mechanisms against this pathogen remain incompletely understood. In the current study, we hypothesized that the chemokine ligand monocyte chemotactic protein-1, also designated CC chemokine ligand-2 (MCP-1/CCL2) is necessary for effective host defense against invasive aspergillosis in immunocompromised hosts. We found a rapid and marked induction of MCP-1/CCL2 in the lungs of neutropenic mice with invasive aspergillosis. Neutralizing MCP-1/CCL2 resulted in twofold greater mortality and greater than threefold increase in pathogen burden in the lungs. Neutralization of MCP-1/CCL2 also resulted in reduced recruitment of NK cells to the lungs at early time points, but did not affect the number of other leukocyte effector cells in the lungs. Ab-mediated depletion of NK cells similarly resulted in impaired defenses against the infection, resulting in a greater than twofold increase in mortality and impaired clearance of the pathogen from the lungs. These data establish MCP-1/CCL2-mediated recruitment of NK cells to the lungs as a critical early host defense mechanism in invasive aspergillosis and demonstrate NK cells to be an important and previously unrecognized effector cell in this infection.
 ...
PMID:Chemokine-mediated recruitment of NK cells is a critical host defense mechanism in invasive aspergillosis. 1467 81

Pulmonary fibrosis is caused by various known and unknown aetiologies, but the key pathogenic mechanisms are still ill-defined. Chemokines are a large family of chemotactic cytokines that play pivotal roles in various inflammatory diseases. In the present study, the roles of chemokines in a rat model of radiation pneumonitis/ pulmonary fibrosis were examined. Accumulation of inflammatory cells and pneumonitis were observed on day 28, and diffuse alveolar wall thickening with extensive fibrosis was observed on day 56. In addition to the previously reported CCL2 (macrophage chemoattractant protein-1) induction, selective upregulation of CCL22 (macrophage-derived chemokine) and CCL17 (thymus and activation-regulated chemokine) were demonstrated for the first time in the irradiated lung tissues. Immunohistochemically, it was demonstrated that CCL22 and CCL17 were localised primarily to alveolar macrophages, whereas their receptor CC chemokine receptor 4 (CCR4) was detected on alveolar lymphocytes and macrophages. On further analysis of bronchoalveolar lavage fluid from patients with idiopathic pulmonary fibrosis and sarcoidosis, elevated levels of CCL22, but not of CCL17, were observed in the idiopathic pulmonary fibrosis patients. Since these two chemokines play pivotal roles in various type-2 T-helper cell-dominant diseases, it was speculated that CCL22, and probably CCL17, are involved in the pathophysiology of radiation pneumonitis/pulmonary fibrosis and idiopathic pulmonary fibrosis through the recruitment of CC chemokine receptor 4-positive type-2 T-helper cells and alveolar macrophages.
 ...
PMID:CCL22 and CCL17 in rat radiation pneumonitis and in human idiopathic pulmonary fibrosis. 1529 4

Influenza A virus pneumonia is characterized by severe lung injury and high mortality. Early infection elicits a strong recruitment of monocytes from the peripheral blood across the endo-/epithelial barrier into the alveolar air space. However, it is currently unclear which of the infected resident lung cell populations, alveolar epithelial cells or alveolar macrophages, elicit monocyte recruitment during influenza A virus infection. In the current study, we investigated whether influenza A virus infection of primary alveolar epithelial cells and resident alveolar macrophages would elicit a basal-to-apical monocyte transepithelial migration in vitro. We found that infection of alveolar epithelial cells with the mouse-adapted influenza A virus strain PR/8 strongly induced the release of monocyte chemoattractants CCL2 and CCL5 followed by a strong monocyte transepithelial migration, and this monocytic response was strictly dependent on monocyte CCR2 but not CCR5 chemokine receptor expression. Analysis of the adhesion molecule pathways demonstrated a role of ICAM-1, VCAM-1, integrin-associated protein (CD47), and junctional adhesion molecule-c on the epithelial cell surface interacting with monocyte beta(1) and beta(2) integrins and integrin-associated protein in the monocyte transmigration process. Importantly, addition of influenza A virus-infected alveolar macrophages further enhanced monocyte transmigration across virus-infected epithelium in a TNF-alpha-dependent manner. Collectively, the data show an active role for virus-infected alveolar epithelium in the regulation of CCL2/CCR2-dependent monocyte transepithelial migration during influenza infection that is essentially dependent on both classical beta(1) and beta(2) integrins but also junctional adhesion molecule pathways.
 ...
PMID:Alveolar epithelial cells direct monocyte transepithelial migration upon influenza virus infection: impact of chemokines and adhesion molecules. 1684 92

Adoptive transfer of CD4+CD25+ regulatory T cells has been shown to have therapeutic effects in animal models of autoimmune diseases. Chemokines play an important role in the development of autoimmune diseases in animal models and humans. The present study was performed to investigate whether the progression of organ-specific autoimmune diseases could be reduced more markedly by accumulating chemokine receptor-expressing CD4+CD25+ regulatory T cells efficiently in target organs in MRL/MpJ-lpr/lpr (MRL/lpr) mice. CD4+CD25+Foxp3+ T cells (Treg cells) and CD4+CD25+Foxp3+ CCR2-transfected T cells (CCR2-Treg cells) were transferred via retro-orbital injection into 12-week-old MRL/lpr mice at the early stage of pneumonitis and sialadenitis, and the pathological changes were evaluated. Expression of monocyte chemoattractant protein-1 (MCP-1)/CCL2 was observed in the lung and submandibular gland of the mice and increased age-dependently. The level of CCR2 expression and MCP-1 chemotactic activity of CCR2-Treg cells were much higher than those of Treg cells. MRL/lpr mice to which CCR2-Treg cells had been transferred showed significantly reduced progression of pneumonitis and sialadenitis in comparison with MRL/lpr mice that had received Treg cells. This was due to more pronounced migration of CCR2-Treg cells and their localization for a longer time in MCP-1-expressing lung and submandibular gland, resulting in stronger suppressive activity. We prepared chemokine receptor-expressing Treg cells and demonstrated their ability to ameliorate disease progression by accumulating in target organs. This method may provide a new therapeutic approach for organ-specific autoimmune diseases in which the target antigens remain undefined.
 ...
PMID:Therapy for pneumonitis and sialadenitis by accumulation of CCR2-expressing CD4+CD25+ regulatory T cells in MRL/lpr mice. 1728 25

Mononuclear phagocytes are critical components of the innate host defense of the lung to inhaled bacterial pathogens. The monocyte chemotactic protein CCL2 plays a pivotal role in inflammatory mononuclear phagocyte recruitment. In this study, we tested the hypothesis that increased CCL2-dependent mononuclear phagocyte recruitment would improve lung innate host defense to infection with Streptococcus pneumoniae. CCL2 transgenic mice that overexpress human CCL2 protein in type II alveolar epithelial cells and secrete it into the alveolar air space showed a similar proinflammatory mediator response and neutrophilic alveolitis to challenge with S. pneumoniae as wild-type mice. However, CCL2 overexpressing mice showed an improved pneumococcal clearance and survival compared with wild-type mice that was associated with substantially increased lung mononuclear phagocyte subset accumulations upon pneumococcal challenge. Surprisingly, CCL2 overexpressing mice developed bronchiolitis obliterans upon pneumococcal challenge. Application of anti-CCR2 Ab MC21 to block the CCL2-CCR2 axis in CCL2 overexpressing mice, though completely abrogating bronchiolitis obliterans, led to progressive pneumococcal pneumonia. Collectively, these findings demonstrate the importance of the CCL2-CCR2 axis in the regulation of both the resolution/repair and remodelling processes after bacterial challenge and suggest that overwhelming innate immune responses may trigger bronchiolitis obliterans formation in bacterial lung infections.
 ...
PMID:Lung-specific overexpression of CC chemokine ligand (CCL) 2 enhances the host defense to Streptococcus pneumoniae infection in mice: role of the CCL2-CCR2 axis. 1744 67

Pretreatment of mice with the hemopoietic growth factor, FMS-like tyrosine kinase 3 ligand (Flt3L), has been shown to increase monocyte-derived myeloid dendritic cells (DC) in lung parenchymal tissue, with possible implications for protective immunity to lung bacterial infections. However, whether Flt3L treatment improves lung innate immunity of mice to challenge with Streptococcus pneumoniae has not been investigated previously. Mice pretreated with Flt3L exhibited a peripheral monocytosis and a strongly expanded lung myeloid DC pool, but responded with a similar proinflammatory cytokine release (TNF-alpha, IL-6, keratinocyte derived cytokine, MIP-2, CCL2) and neutrophilic alveolitis upon infection with S. pneumoniae as did control mice with a normal lung DC pool. Unexpectedly, however, Flt3L-pretreated mice, but not control mice, infected with S. pneumoniae developed vasculitis and increased lung permeability by days 2-3 postinfection, and florid pneumonia accompanied by sustained increased bacterial loads by days 3-4 postinfection. This was associated with an overall increased mortality of approximately 35% by day 4 after pneumococcal challenge. Application of anti-CCR2 Ab MC21 to block inflammatory monocyte-dependent lung mononuclear phagocyte mobilization significantly reduced the lung leakage, but not vasculitis in Flt3L-pretreated mice infected with S. pneumoniae, without affecting the intra-alveolar cytokine liberation or the concomitantly developing neutrophilic alveolitis. Together, the data demonstrate that previous Flt3L-induced lung DC accumulation is not protective in lung innate immunity to challenge with S. pneumoniae, and support the concept that CCR2-dependent mononuclear phagocyte as opposed to neutrophil recruitment contributes to increased lung leakage in Flt3L-pretreated mice challenged with S. pneumoniae.
 ...
PMID:FMS-like tyrosine kinase 3 ligand aggravates the lung inflammatory response to Streptococcus pneumoniae infection in mice: role of dendritic cells. 1770 24

We investigated the roles of the potent, chemotactic antimicrobial proteins S100A8, S100A9, and S100A8/A9 in leukocyte migration in a model of streptococcal pneumonia. We first observed differential secretion of S100A8, S100A9, and S100A8/A9 that preceded neutrophil recruitment. This is partially explained by the expression of S100A8 and S100A9 proteins by pneumocytes in the early phase of Streptococcus pneumoniae infection. Pretreatment of mice with anti-S100A8 and anti-S100A9 Abs, alone or in combination had no effect on bacterial load or mice survival, but caused neutrophil and macrophage recruitment to the alveoli to diminish by 70 and 80%, respectively, without modifying leukocyte blood count, transendothelial migration or neutrophil sequestration in the lung vasculature. These decreases were also associated with a 68% increase of phagocyte accumulation in lung tissue and increased expression of the chemokines CXCL1, CXCL2, and CCL2 in lung tissues and bronchoalveolar lavages. These results show that S100A8 and S100A9 play an important role in leukocyte migration and strongly suggest their involvement in the transepithelial migration of macrophages and neutrophils. They also indicate the importance of antimicrobial proteins, as opposed to classical chemotactic factors such as chemokines, in regulating innate immune responses in the lung.
 ...
PMID:Blockade of antimicrobial proteins S100A8 and S100A9 inhibits phagocyte migration to the alveoli in streptococcal pneumonia. 1829 62

Cyclophosphamide (CYC) can control diffuse proliferative lupus nephritis (DPLN) by potent immunosuppression but remains associated with serious and life-threatening complications. Drugs that specifically target mediators of DPLN may help to reduce CYC dose and side effects. Monocyte chemoattractant protein (MCP-1)/CCL2 mediates monocyte and T cell recruitment in DPLN and Ccl2-specific l-enantiomeric RNA Spiegelmer mNOX-E36 neutralizes the biological effects of murine Ccl2 in vitro and in vivo. We injected MRL(lpr/lpr) mice with DPLN from 14 weeks of age with vehicle, weekly 30 mg/kg CYC (full dose), monthly 30 mg/kg CYC (one-fourth full dose), pegylated control Spiegelmer, pegylated anti-Ccl2 Spiegelmer (3/week), pegylated anti-Ccl2 Spiegelmer plus CYC one-fourth full dose and mycophenolate mofetil. At week 24, DPLN and autoimmune lung injury were virtually abolished with CYC full dose but not with CYC one-fourth full dose. The CYC one-fourth full dose/Spiegelmer combination was equipotent to CYC full dose on kidney and lung injury. CD3(+)CD4(-)CD8(-) and CD3(+)CD4(+)CD25(+) T cells and serum interleukin-12p40 and tumor necrosis factor-alpha levels were all markedly affected by CYC full dose but not by CYC one-fourth full dose. No additive effects of anti-Ccl2 Spiegelmer were noted on bone marrow colony-forming unit-granulocyte macrophage counts and 7/4(high) monocyte counts, lymphoproliferation, and spleen T cell depletion. In summary, anti-Ccl2 Spiegelmer permits 75% dose reduction of CYC for controlling DPLN and pneumonitis in MRL-Fas(lpr) mice, sparing suppressive effects of full-dose CYC on myelosuppression and T cell depletion. We propose anti-Ccl2 Spiegelmer therapy as a novel strategy to reduce CYC toxicity in the treatment of severe lupus.
 ...
PMID:Anti-Ccl2 Spiegelmer permits 75% dose reduction of cyclophosphamide to control diffuse proliferative lupus nephritis and pneumonitis in MRL-Fas(lpr) mice. 1899 60

Respiratory syncytial virus (RSV) is a common cause of infection that is associated with a range of respiratory illnesses, from common cold-like symptoms to serious lower respiratory tract illnesses such as pneumonia and bronchiolitis. RSV is the single most important cause of serious lower respiratory tract illness in children <1 year of age. Host innate and acquired immune responses activated following RSV infection have been suspected to contribute to RSV disease. Toll-like receptors (TLRs) activate innate and acquired immunity and are candidates for playing key roles in the host immune response to RSV. Leukocytes express TLRs, including TLR2, TLR6, TLR3, TLR4, and TLR7, that can interact with RSV and promote immune responses following infection. Using knockout mice, we have demonstrated that TLR2 and TLR6 signaling in leukocytes can activate innate immunity against RSV by promoting tumor necrosis factor alpha, interleukin-6, CCL2 (monocyte chemoattractant protein 1), and CCL5 (RANTES). As previously noted, TLR4 also contributes to cytokine activation (L. M. Haynes, D. D. Moore, E. A. Kurt-Jones, R. W. Finberg, L. J. Anderson, and R. A. Tripp, J. Virol. 75:10730-10737, 2001, and E. A. Kurt-Jones, L. Popova, L. Kwinn, L. M. Haynes, L. P. Jones, R. A. Tripp, E. E. Walsh, M. W. Freeman, D. T. Golenbock, L. J. Anderson, and R. W. Finberg, Nat. Immunol. 1:398-401, 2000). Furthermore, we demonstrated that signals generated following TLR2 and TLR6 activation were important for controlling viral replication in vivo. Additionally, TLR2 interactions with RSV promoted neutrophil migration and dendritic cell activation within the lung. Collectively, these studies indicate that TLR2 is involved in RSV recognition and subsequent innate immune activation.
 ...
PMID:Respiratory syncytial virus activates innate immunity through Toll-like receptor 2. 1901 63


1 2 3 4 5 6 Next >>