Production of colony‐stimulating factor‐1 (CSF‐1) by mouse astroglia in vitro

Abstract

We investigated whether astroglia produce any of the known macrophage growth factors, CSF‐1, GM‐CSF, and IL‐3, and if so, whether any of these cytokines stimulate the growth of CNS macrophages. In this work we used highly enriched cell cultures of C3H/HeJ mouse neopallium: cultures of astroglia and cultures of macrophage‐like cells derived from nutritionally deprived astroglia cultures. We found that astroglia in cultures accumulate in the medium, an activity that stimulates the proliferation of macrophage‐like cells. The activity has been identified as CSF‐1 by using growth assays of cells dependent and nondependent on CSF‐1, and by radioreceptor analysis which is highly specific for CSF‐1. Northern blot analysis demonstrated the presence in astroglia of CSF‐1 mRNA and the presence of CSF‐1 receptor (c‐fms) mRNA in macrophage‐like cells but not in astroglia. The astroglia did not produce GM‐CSF or IL‐3. We concluded that a paracrine relationship exists between astroglia production of CSF‐1 and the response of macrophage‐like cells to the cytokine in culture.