title: Spontaneous expression of the c-sis gene and release of a platelet-derived growth factorlike molecule by human alveolar macrophages.
abstract: Alveolar macrophages from normal individuals and patients with interstitial lung diseases spontaneously expressed a 4.2-kilobase mRNA complementary to the c-sis gene, a proto-oncogene coding for one of the chains of platelet-derived growth factor (PDGF). Concomitantly, these cells released a mediator with the properties of PDGF, including: chemotactic factor for smooth muscle cells whose activity was resistant to heat and acid, but sensitive to reduction; mitogenic (competence) activity for fibroblasts; ability to compete with PDGF for its receptor; and precipitated by an anti-PDGF antibody. While blood monocytes did not contain c-sis mRNA transcripts, monocytes matured in vitro expressed c-sis, consistent with the concept that expression of c-sis occurs during the differentiation of monocytes into alveolar macrophages. Together with the known actions of PDGF, these observations suggest that the c-sis proto-oncogene and its PDGF product are part of the armamentarium available to the alveolar macrophages for normal lung defense and participation in lung inflammation.
mesh_terms: D002633:Chemotaxis; D003513:Cycloheximide / Q000494:pharmacology; D005786:Gene Expression Regulation; D006358:Hot Temperature; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008171:Lung Diseases / Q000235:genetics / Q000378:metabolism*; D010982:Platelet-Derived Growth Factor / Q000235:genetics / Q000378:metabolism*; D000090063:Proto-Oncogene Mas; D011519:Proto-Oncogenes; D011650:Pulmonary Alveoli / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D011863:Radioimmunoassay; D014158:Transcription, Genetic; D014357:Trypsin / Q000378:metabolism
chemical_list: C000715470:MAS1 protein, human; D010982:Platelet-Derived Growth Factor; D000090063:Proto-Oncogene Mas; D012333:RNA, Messenger; D003513:Cycloheximide; D014357:Trypsin