Wound macrophages express TGF-alpha and other growth factors in vivo: analysis by mRNA phenotyping.
The presence of macrophages is required for the regeneration of many cell types during wound healing. Macrophages have been reported to express a wide range of mitogenic factors and cytokines, but none of these factors has been shown in vivo to sustain all the wound-healing processes. It has been suggested that transforming growth factor-alpha (TGF-alpha) may mediate angiogenesis, epidermal regrowth, and formation of granulation tissue in vivo. Macrophages isolated from a wound site, and not exposed to cell culture conditions, expressed messenger RNA transcripts for TGF-alpha, TGF-beta, platelet-derived growth factor A-chain, and insulin-like growth factor-1. The expression of these transcripts was determined by a novel method for RNA analysis in which low numbers of mouse macrophages were isolated from wound cylinders, their RNA was purified and reverse-transcribed, and the complementary DNA was amplified in a polymerase chain reaction primed with growth factor sequence-specific primers. This single-cell RNA phenotyping procedure is rapid and has the potential for quantification, and mRNA transcripts from a single cell or a few cells can be unambiguously demonstrated, with the simultaneous analysis of several mRNA species. Macrophages from wounds expressed TGF-alpha antigen, and wound fluids contained TGF-alpha. Elicited macrophages in culture also expressed TGF-alpha transcripts and polypeptide in a time-dependent manner after stimulation with modified low-density lipoproteins and lipopolysaccharide endotoxin, which are characteristic of the activators found in injured tissues.
D000818:Animals; D002460:Cell Line; D004247:DNA / Q000235:genetics; D004797:Enzyme-Linked Immunosorbent Assay; D004815:Epidermal Growth Factor / Q000096:biosynthesis / Q000235:genetics; D005346:Fibroblast Growth Factors / Q000096:biosynthesis / Q000235:genetics; D005347:Fibroblasts / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D006133:Growth Substances / Q000096:biosynthesis* / Q000235:genetics; D007334:Insulin-Like Growth Factor I / Q000096:biosynthesis / Q000235:genetics; D008264:Macrophages / Q000378:metabolism*; D008297:Male; D051379:Mice; D009693:Nucleic Acid Hybridization; D010452:Peptide Biosynthesis; D010455:Peptides / Q000235:genetics; D010982:Platelet-Derived Growth Factor / Q000096:biosynthesis / Q000235:genetics; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis*; D011817:Rabbits; D014158:Transcription, Genetic; D015291:Transforming Growth Factors; D014945:Wound Healing; D014947:Wounds and Injuries / Q000473:pathology*
D006133:Growth Substances; D010455:Peptides; D010982:Platelet-Derived Growth Factor; D012333:RNA, Messenger; D005346:Fibroblast Growth Factors; D004815:Epidermal Growth Factor; D007334:Insulin-Like Growth Factor I; D015291:Transforming Growth Factors; D004247:DNA