Alveolar macrophages release an insulin-like growth factor I-type molecule. Academic Article uri icon

Overview

MeSH

  • Binding, Competitive
  • Chromatography, Ion Exchange
  • Humans
  • Macrophage Activation
  • RNA, Messenger

MeSH Major

  • Insulin-Like Growth Factor I
  • Macrophages
  • Pulmonary Alveoli
  • Somatomedins

abstract

  • Human alveolar macrophages, when activated, release a progression-type growth factor for fibroblasts that signals "competent" fibroblasts to replicate. The present study demonstrates that this growth activity is an insulin-like growth factor I (IGF-I)-type molecule. Partial purification of medium conditioned by activated alveolar macrophages using ion exchange and gel filtration chromatography revealed an IGF-I molecule as detected by an anti-IGF-I polyclonal antibody and that the specific activity of the progression-type growth activity tracked with the amount of IGF-I present. In a serum-free complementation test, the increase in fibroblast proliferation by alveolar macrophage IGF-I was reduced in a dose-response manner with an anti-IGF-I monoclonal antibody. The alveolar macrophage IGF-I displaced 125I-IGF-I from its receptor in a binding assay utilizing human lung fibroblasts and it stimulated type I IGF receptors purified from human lung fibroblasts to phosphorylate a tyrosine-containing artificial substrate. In contrast to the 7.6-kD serum IGF-I, gel chromatography revealed that the alveolar macrophage IGF-I had an apparent molecular mass of 26 kD, similar to other tissue IGF-Is. Alveolar macrophages expressed IGF-I mRNA transcripts as detected by solution hybridization using a 32P-labeled riboprobe complementary to exons I-II-III of the IGF-I gene. In the context of the known functions of the family of IGF-I molecules in cell growth, IGF-I released by activated alveolar macrophages may play a role in acute and chronic inflammatory disorders.

publication date

  • November 1988

has subject area

  • Binding, Competitive
  • Chromatography, Ion Exchange
  • Humans
  • Insulin-Like Growth Factor I
  • Macrophage Activation
  • Macrophages
  • Pulmonary Alveoli
  • RNA, Messenger
  • Somatomedins

Research

keywords

  • Journal Article

Identity

Language

  • eng

PubMed Central ID

  • PMC442738

Digital Object Identifier (DOI)

  • 10.1172/JCI113781

PubMed ID

  • 3183063

Additional Document Info

start page

  • 1685

end page

  • 1693

volume

  • 82

number

  • 5