The complement anaphylatoxin peptides, C3a and C5a are well known mediators of inflammatory reactions in the lung. During the initial funding period of this research studies were begun into the cellular and molecular mechanisms of anaphylatoxin-induced injury using isolated lung tissues from both human and guinea pig. Evidence was obtained to show that contractile responses of isolated lung parenchymal strips induced by C5a and its metabolites C5adesArg are mediated by production of leukotrienes that constitute SRS-A and release of a small amount of histamine. C3a, in contrast, induces contractile responses by releasing cyclooxygenase metabolites but no detectable leukotrienes. Platelet-activating factor (PAF), an unusual phospholipid mediator released from inflammatory cells stimulated with C5a, also contracts lung parenchymal tissues from both human and guinea pig. PAF stimulates release of significant quantities of thromboxane from guinea pig lung, however indomethacin alone does not block contractile responses of the tissue. Evidence has recently been obtained indicating that PAF may act on parasympathetic neurons to release acetylcholine, and this may be a major component of tissue responses to this agonist. In this RCDA application studies are proposed to continue these investigations using the same general approach. Bioactive mediators released from lung by C3a and C5a will continue to be characterized. The contribution of these mediators to anaphylatoxin-mediated lung injury will be evaluated by studying the interactions of these mediators using in vitro assays. Investigations into the mechanism of PAF-induced activation of parasympathetic pathways in the lung will be expanded. Target cells for the anaphylatoxins will be identified and the role of the pulmonary vascular endothelium in binding, mediator release and degradation of the peptides will be evaluated. Finally, similar studies are planned using human lung tissues with the ultimate goal of understanding the mechanisms of anaphylatoxin induced pulmonary injury.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Modified Research Career Development Award (K04)
Project #
1K04HL001777-01
Application #
3074050
Study Section
Pathology A Study Section (PTHA)
Project Start
1985-09-01
Project End
1990-08-31
Budget Start
1985-09-01
Budget End
1986-08-31
Support Year
1
Fiscal Year
1985
Total Cost
Indirect Cost
Name
Beth Israel Deaconess Medical Center
Department
Type
DUNS #
076593722
City
Boston
State
MA
Country
United States
Zip Code
Gerard, N P; Gerard, C (1991) Molecular cloning of the human neurokinin-2 receptor cDNA by polymerase chain reaction and isolation of the gene. Ann N Y Acad Sci 632:389-90
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Gerard, N P; Gerard, C (1990) Construction and expression of a novel recombinant anaphylatoxin, C5a-N19, as a probe for the human C5a receptor. Biochemistry 29:9274-81
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Watson, J W; Drazen, J M; Stimler-Gerard, N P (1988) Synergism between inflammatory mediators in vivo. Induction of airway hyperresponsiveness to C3a in the guinea pig. Am Rev Respir Dis 137:636-40
Gerard, N P; Lively, M O; Gerard, C (1988) Amino acid sequence of guinea pig C3a anaphylatoxin. Protein Seq Data Anal 1:473-8
Gerard, N P (1987) Characterization of substance P contractile activity on isolated guinea pig lung tissues. J Pharmacol Exp Ther 243:901-6
Stimler-Gerard, N P (1987) Neutral endopeptidase-like enzyme controls the contractile activity of substance P in guinea pig lung. J Clin Invest 79:1819-25
Shore, S A; Stimler-Gerard, N P; Smith, E et al. (1987) A formyl peptide contracts guinea pig lung: role of arachidonic acid metabolites. J Appl Physiol 63:2450-9

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