Glial growth factor 2 induces proliferation and structural changes in ensheathing cells

Ensheathing cells were isolated from neonatal rat olfactory bulbs and cultu red in the presence of glial growth factor 2 (GGF2). Proliferation assay sh owed that at concentrations of up to 60 ng/ml GGF2, ensheathing cells under went a modest increase in proliferation rate. This stimulation was not main tained at high doses of GGF2 at 100 ng/ml or more. Chemotaxis chambers and scanning electron microscopy were used to determine whether GGF2 was a chem oattractant for ensheathing cells. Although the results showed no chemotact ic response to GGF2, ensheathing cells demonstrated structural changes when cultured in the presence of 20 ng/ml GGF2. Ultrastructural observations re vealed that GGF2 promoted increased deposition of extracellular matrix on t he cell membrane, more cytoskeletal elements in the processes and as a poss ible consequence, contributed to a more rigid support. Ensheathing cells cu ltured in the absence of GGF2 often extended thinner and curved processes. Reverse transcription-polymerase chain reaction confirmed the presence of G GF2 transcripts in ensheathing cells, suggesting that ensheathing cells the mselves are a source of GGF2. (C) 2000 Elsevier Science B.V. All rights res erved.