Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In a variety of diseases including asthma, inflammation causes microvascular leakage and activates thrombin. In addition to cleaving fibrinogen to fibrin, thrombin may have other important cellular effects. Because airway inflammation and vascular permeability are important determinants of airway hyperreactivity, we have studied the effects of thrombin on airway smooth muscle. Using cultured human airway smooth muscle cells, we have examined whether alpha-thrombin can evoke calcium responses, phosphoinositide turnover, or cell proliferation. We have demonstrated that alpha-thrombin does increase cytosolic calcium and phosphoinositide hydrolysis in a dose- and time-dependent manner that may be inhibited by pretreating cells with r-hirudin. In addition, we have shown that thrombin stimulates airway smooth muscle cell proliferation. By contrast, bradykinin, which evoked comparable increases in cytosolic calcium and phosphoinositide turnover, did not stimulate airway smooth muscle cell growth. We conclude that thrombin effectively increases cytosolic calcium and induces PI hydrolysis and, in addition, is capable of stimulating airway smooth muscle cell growth. However, the lack of an effect of bradykinin on cell growth suggests that increases in calcium and PI turnover alone will not induce airway smooth muscle cell proliferation. We suggest that alpha-thrombin may be important in the pathogenesis of both increased airway resistance as well as the structural changes seen as a consequence of chronic asthma.
Am J Respir Cell Mol Biol 1995 Aug
PMID:alpha-Thrombin increases cytosolic calcium and induces human airway smooth muscle cell proliferation. 762 88

Protein kinase C (PKC) has been implicated in the control of airway smooth muscle (ASM) tone, and abnormalities in PKC-dependent signaling may be associated with asthma. PKC exists in different isoforms, but the pattern of their expression in ASM has not been previously reported. Accordingly, the purpose of the present study was to identify which isoforms of PKC are expressed in ASM. Tissue samples of canine ASM were homogenized and subjected to sodium dodecyl sulfate polyacrylamide gel electrophoresis, followed by immunoblotting with a range of antipeptide antibodies to PKC-alpha, -beta I, -beta II, -gamma, -delta, -epsilon, -eta, -theta, and -zeta. Positive controls were run in parallel with ASM. Immunoblots revealed a mixture of both calcium-dependent and calcium-independent isozymes: PKC-beta I and PKC-beta II were the only conventional isoforms detected; PKC-delta, PKC-epsilon, and the new muscle-specific isoform, PKC-theta, were all expressed in ASM, but the lung-specific isoform, PKC-eta, was not detected. The calcium- and phospholipid-independent isoform, PKC-zeta, was also present. Thus, expression of a wide variety of both calcium-dependent and calcium-independent isoforms suggests a complex, multifunctional role of PKC in ASM.
Am J Respir Cell Mol Biol 1995 Sep
PMID:Expression of multiple isoenzymes of protein kinase C in airway smooth muscle. 765 81

Previous studies have indicated an increased number of beta 2-adrenergic receptors (beta 2AR) on bronchial smooth muscle in fatal asthma. This study evaluates the utility of autopsy lung for studies of gene expression and examines the hypothesis that increased expression of beta 2 AR mRNA in peripheral lung underlies the increased receptor number reported in central airways in fatal asthma. beta 2AR mRNA levels have been quantitated using the ribonuclease protection assay on RNA from peripheral lung obtained both at autopsy and thoracotomy from subjects with normal lungs as well as subjects with asthma or chronic obstructive pulmonary disease (COPD). Glucocorticosteroid and serum induction of beta 2AR mRNA in human epidermoid carcinoma A431 cells, which display a high abundance of beta 2AR receptors, was also examined to provide aliquots of RNA containing relatively high levels of beta 2AR mRNA for use as positive controls and internal standards. In A431 cells maintained after confluence in serum-free media for 72 h, maximal beta 2AR mRNA levels in response to 10% fetal bovine serum were 85% of maximal levels following serum plus 10 microM dexamethasone. Both autopsy and resected lung yielded undegraded RNA with a similar relative abundance of beta 2AR mRNA. Although geometric mean beta 2AR mRNA levels were similar in all three patient groups, relatively high levels were observed in resected lung in a subpopulation of subjects with mild or moderate asthma but not in autopsy lung from subjects with severe asthma. High levels of beta 2AR mRNA, presumably reflecting lung growth or asthma, were demonstrated in peripheral lung of a 4-yr-old child with asthma.(ABSTRACT TRUNCATED AT 250 WORDS)
Am J Respir Cell Mol Biol 1993 Mar
PMID:Expression of beta 2-adrenergic receptor mRNA in peripheral lung in asthma and chronic obstructive pulmonary disease. 768 May 66

Heparin from degranulating mast cells influences a wide range of cellular and humoral reactions associated with allergic inflammation and asthma. Agents that inhibit mast cell degranulation may therefore compromise the moderating effects of heparin in the tissues and result in worsening inflammation and other associated pathology. This study measures heparin release from allergen-challenged human lung tissue and compares the effect of the mast cell stabilizing beta 2-agonists, salbutamol and fenoterol, and a non-beta 2-agonist, sodium cromoglycate, on the release of heparin. Pieces of lung tissue 2 to 3 mm3 were sensitized with high titer Dermatoaphagoides pteronyssinus-specific IgE serum and challenged with D. pteronyssinus allergen, with and without prior addition of salbutamol, fenoterol, or sodium cromoglycate. Dextran sulfate was added to the mixture to prevent the binding of heparin to tissue proteins. Heparin was released together with histamine after challenge. The mean and 95% confidence interval of prechallenge and postchallenge heparin concentrations in the lung tissue filtrates were 0.10 IU/ml (0.07, 0.12) and 0.24 IU/ml (0.17, 0.30), respectively (P < 0.001). Addition of the beta 2-agonists produced a mean inhibition of released heparin of 71% (50, 92), and 73% (55, 91), respectively. Sodium cromoglycate gave a 35% (20, 51) inhibition that was significantly less than that produced by the beta 2-agonists (P < 0.01). The beta 2-agonists salbutamol and fenoterol strongly inhibited heparin release from mast cells. The therapeutic use of mast cell stabilizing agents may therefore be potentially detrimental to the control of allergic inflammation and other associated pathologies.
Am J Respir Cell Mol Biol 1993 May
PMID:Effect of salbutamol, fenoterol, and sodium cromoglycate on the release of heparin from sensitized human lung fragments challenged with Dermatophagoides pteronyssinus allergen. 768 96

Biochemical studies of pollen proteins have been focused, primarily, in investigating their roles as allergens. These molecules, some of which have enzymatic activity, act as antigens and initiate the production of IgE antibodies, leading to allergic and/or asthmatic responses. Included in this mixture of proteins are proteinases which, although they may or may not be allergenic, could still be involved in airway dysfunction. We have isolated an arginine-specific endopeptidase to homogeneity from mesquite (Prosopis velutina) pollen, a known wind-borne allergen, which has a molecular mass near 84 kDa by NaDodSO4-gel electrophoresis, a pH optimum in the neutral to alkaline range, and a requirement for Ca2+ for stabilization. The enzyme is inhibited by diisopropyl fluorophosphate (DFP) and N-p-tosyl-L-lysine chloromethylketone but not by N-p-tosyl-L-phenylalanine chloromethylketone, EDTA, or iodoacetamide. It was also not inhibited by human plasma proteinase inhibitors nor several other naturally occurring plant and animal inhibitors. Cleavage by the endopeptidase was primarily on the carboxy-terminal side of arginine residues in peptides, whereas proteins such as kallikrein and prothrombin were only activated and/or degraded extremely slowly. Several bioactive peptides that may be involved in maintaining normal lung function were readily fragmented, including angiotensin II, a vasoconstrictor, and atrial natriuretic peptide, a modulator of vascular permeability, both of which were rapidly cleaved at low enzyme:substrate molar ratios. Thus, the pollen endopeptidase could be involved in exacerbating the development of asthma by inactivating bioactive peptides that have ameliorating effects in maintaining lung airway homeostasis.
Am J Respir Cell Mol Biol 1995 Apr
PMID:Isolation and properties of an angiotensin II-cleaving peptidase from mesquite pollen. 769 24

We investigated the phenotype of cells expressing messenger RNA encoding interleukin 4 (IL-4), IL-5, IL-2, and interferon gamma (IFN-gamma) in bronchoalveolar lavage (BAL) and bronchial biopsies (BX) from seven mild atopic asthmatic patients and nine nonasthmatic controls. Immunocytochemistry followed by in situ hybridization using either 35S- or digoxigenin-labeled riboprobes was performed on cytospins from BAL and BX, respectively. With BAL or BX, in situ hybridization alone showed significant increases in percentages of IL-2, IL-4, and IL-5 mRNA+ cells when asthmatics were compared to nonasthmatic controls. Double immunocytochemistry-in situ hybridization revealed that > 70% of IL-4 and IL-5 mRNA+ cells were activated T cells (CD3+). The remaining IL-4 and IL-5 mRNA+ signals were colocalized to tryptase+ mast cells, and activated eosinophils (EG2+). Rare IL-4 and IL-5 mRNA+ cells were observed in nonasthmatic controls, the majority being CD3+ cells, as were IL-2 and IFN-gamma mRNA+ cells (in both asthmatics and controls). A few IL-4 (< 8%) and IL-5 (< 5%) mRNA+ signals did not colocalize with any of the cells identified by immunocytochemistry. Thus, we provide further evidence that CD3+ T cells are the most abundant cells expressing IL-4 and IL-5 mRNA in BAL and BX from allergic asthma. Fewer, but detectable, numbers of tryptase+ mast cells and EG2+ eosinophils also expressed these transcripts.
Am J Respir Cell Mol Biol 1995 May
PMID:Phenotype of cells expressing mRNA for TH2-type (interleukin 4 and interleukin 5) and TH1-type (interleukin 2 and interferon gamma) cytokines in bronchoalveolar lavage and bronchial biopsies from atopic asthmatic and normal control subjects. 774 12

beta 2-Adrenergic receptor (beta 2 AR) autoantibodies have been reported in the serum from subjects with asthma but the functional significance of such antibodies is not known. To characterize these antibodies, we developed a Western blot (WB) technique that utilized overexpressed recombinant human beta 2AR as antigen and also developed a control antisera in rabbits directed against the C-terminus of the receptor. beta 2AR autoantibodies were detected in approximately 5% of normal subjects and in approximately 40% of asthmatic subjects. Eighty-four percent of these antibodies were of the IgG class, with the remainder being IgM. Most (73%) of WB-positive sera inhibited [125I]cyanopindolol binding to recombinant solubilized receptors. The mean binding inhibition was 40.4 +/- 5.1% for WB-positive sera versus 7.6 +/- 1.2% for WB-negative sera. Binding of antibody to beta 2AR expressed on intact cells significantly depressed receptor function, with a > 50% attenuation of isoproterenol-stimulated cAMP production. This effect was receptor specific, as forskolin-stimulated cAMP accumulation was not affected by exposure to sera. WB-positive sera that did not inhibit radioligand binding had no effect on receptor function. Thus, some antibodies appear to bind near the ligand binding pocket and act as functional antagonists. In addition, incubation of intact cells expressing beta 2AR with WB-positive sera for 18 h resulted in a 30.3 +/- 0.6% downregulation of receptor number, whereas WB-negative sera induced no downregulation. This downregulation response with WB-positive sera was not affected by coincubation with the antagonist propranolol and was apparently not dependent upon whether the antibody interacted with ligand binding pocket.(ABSTRACT TRUNCATED AT 250 WORDS)
Am J Respir Cell Mol Biol 1995 May
PMID:Receptor-specific functional properties of beta 2-adrenergic receptor autoantibodies in asthma. 774 16

T-lymphocyte (T-LC)-derived cytokines have been implicated in asthma pathogenesis. Activation of peripheral blood CD4 but not CD8 T-LC and a Th2-type pattern of elevated cytokine mRNA expression in BAL fluid T-LC have been observed in asthmatics, but the principal source (CD4 or CD8 T-LC) of these cytokines is unknown. Our objective was to measure expression of Th1- and Th2-type cytokine mRNA and spontaneous secretion of IL-3, IL-5, and GM-CSF by peripheral blood CD4 and CD8 T-LC from asthmatics before and after oral glucocorticoid therapy and non-asthmatic controls. We used in situ hybridization to detect mRNA expression in isolated CD4 and CD8 T-LC, and an in vitro eosinophil survival assay to detect secretion of IL-3, IL-5, and GM-CSF in T-LC culture supernatants. Comparing the asthmatics with the controls, elevated percentages of CD4 T-LC expressed mRNA encoding IL-5, IL-4, and GM-CSF (P < 0.02) but not IL-3, IL-2, or IFN-gamma. In CD8 T-LC, mRNA expression was generally low with no significant differences between the groups. In the asthmatics, the percentages of CD4 T-LC expressing IL-5 mRNA correlated with disease severity and the numbers of peripheral blood eosinophils (P < 0.01). Culture supernatants of asthmatic CD4 but not CD8 T-LC exhibited significantly higher (P = 0.0003) eosinophil survival-prolonging activity compared with controls, in which low activity was detected. Inhibition with anti-cytokine antibodies suggested that GM-CSF, and to a lesser extent IL-5 and IL-3, could account for this activity. After oral glucocorticoid therapy of the asthmatics, lung function improved and the percentages of CD4 T-LC expressing mRNA encoding IL-3, IL-5, and GM-CSF but not IL-2, IL-4, or IFN-gamma were reduced (P < 0.04). Secretion of eosinophil survival-prolonging activity by the CD4 T-LC was also reduced (P = 0.004). We conclude that peripheral blood CD4 but not CD8 T-LC from asthmatics express cytokine mRNA in a Th2-type pattern and show elevated secretion of cytokines prolonging eosinophil survival. Glucocorticoid therapy of asthmatics is associated with a reduction in the percentages of CD4 T-LC expressing IL-3, IL-5, and GM-CSF mRNA and secretion of the corresponding proteins.
Am J Respir Cell Mol Biol 1995 May
PMID:Peripheral blood CD4 but not CD8 t-lymphocytes in patients with exacerbation of asthma transcribe and translate messenger RNA encoding cytokines which prolong eosinophil survival in the context of a Th2-type pattern: effect of glucocorticoid therapy. 774 19

Cytokines released from CD4+ T lymphocytes contribute to the pathogenesis of asthma by influencing the differentiation and function of eosinophils, the primary effector cells that cause airway epithelial damage. Using a model of ovalbumin (OA)-induced, eosinophil-rich chronic lung inflammation in sensitized mice, we have defined the role of T lymphocytes further by using three-color flow cytometry to characterize the adhesion and activation antigens that may be associated with the migration of these cells into the lung and airway lumen. OA inhalation in OA-sensitized C57BL/6 mice resulted in an early (6 to 24 h) influx of neutrophils into the bronchial lumen as enumerated by bronchoalveolar lavage (BAL), which was followed by a marked accumulation of lymphocytes and eosinophils between 24 to 72 h. Phenotypic analysis of BAL or lung tissue T cells showed that most Thy-1 CD3+ T cells were CD4+ (CD4: CD8 ratio of 3 to 4:1). The majority (90%) of the T cells in lung or BAL fluid expressed alpha beta T-cell receptors (TCR). Only 3 to 7% of the T cells were gamma delta TCR+ even though almost 25% of the T cells were CD4- CD8-. There were very few natural killer (NK) or B cells in BAL fluid compared with 15% B cells in dissagregated lung tissue. In contrast to T cells in spleen, almost all the lung and BAL T cells were of the memory phenotype, as ascertained by the expression of high levels of CD44 and by the absence of L-selectin and CD45RB on the cell surface. Fifty to ninety percent of lung and BAL T cells from vehicle-sensitized or OA-sensitized and challenged mice expressed the adhesion molecules CD11a (LFA-1), CD54 (ICAM-1), and CD49d (VLA-4). The early T-cell activation marker CD69 was upregulated on 30% of the lung and BAL T cells in OA-sensitized mice after antigen inhalation. When BAL fluid T cells from OA-sensitized and challenged mice were analyzed for their coexpression of adhesion and/or activation molecules, 75% of the cells that expressed one of three adhesion molecules, CD54, CD49d, or CD11a, also expressed at least one of the other two antigens. At least 15% of BAL T cells had all three of these molecules on their cell surfaces. The OA-dependent, temporally regulated emigration of T cells into the bronchial lumen after exposure to aerosolized antigen may be correlated with the accumulation of cells that express the memory phenotype with enhanced expression of adhesion molecules.
Am J Respir Cell Mol Biol 1995 Jun
PMID:Phenotypic characterization of T lymphocytes emigrating into lung tissue and the airway lumen after antigen inhalation in sensitized mice. 776 26

Allergic inflammation in the lung is characteristic of allergic asthma. This inflammatory process is inhibited by treatment with glucocorticoids. One of the cell types involved in the inflammatory process, the monocyte, is found in enhanced numbers in mucosal lung biopsies of asthmatic patients. Little is known about the mechanisms that lead to increased numbers of monocytes in lung tissue. We studied one of the processes involved, chemotaxis, in a modified Boyden Chamber assay. The effect of the antiinflammatory drug dexamethasone was tested on monocyte chemotactic responses to complement fragment C5a. Human monocytes from peripheral blood of normal human volunteers were purified by centrifugal elutriation. The monocytes showed a reproducible chemotactic response toward C5a with an optimum at a concentration of 10(-9) M. After culture of the monocytes overnight, the monocyte responses were clearly impaired. It is interesting that upon culture, dexamethasone increased monocyte chemotaxis in a dose-dependent manner. Analysis of the filters with an image analyzer showed that the effect was not through modulation of a subpopulation of monocytes. This steroid effect was specific and modulated via steroid receptors, because the introduction of RU 38486, a steroid receptor antagonist, completely inhibited the effect of dexamethasone. These findings are a further illustration of the complex mechanisms involved in the orchestration of the inflammatory response in asthma.
Am J Respir Cell Mol Biol 1995 Jun
PMID:C5a-induced migration of human monocytes is primed by dexamethasone. 776 32


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