Recombinant forms of the neurotrophic factor pigment epithelium-derived factor activate cellular metabolism and inhibit proliferation of the RAW macrophage cell line

Recombinant forms of the neurotrophic factor pigment epithelium-derived fac tor (PEDF) activate metabolism of RAW macrophage cells while simultaneously inhibiting their proliferation. The recombinant forms (rPEDF) acted with E C(50)s of 0.1-1 nM while full-length native bovine PEDF was inactive. Urea, which is the buffer used to extract recombinant PEDF, stimulated RAW cell proliferation, the first report of an effect of urea on non-kidney cells. P EDF acted within 12 h and its effects persisted up to 72 h with continuous exposure. Although rPEDF had no direct action on glioma cell lines, it incr eased the amount of a soluble factor released by RAW cells which was capabl e of blocking glioma cell division. Thus PEDF may function as a neuroimmune modulator, affecting both neural and immune system cells. Copyright (C) 19 99 S. Karger AG, Basel.