Neuregulins and ErbB receptors in cultured neonatal astrocytes

Neuregulins (NRGs) are a family of growth factors involved in signaling bet ween neurons and glial cells of the peripheral and central nervous system, NRGs are synthesized and secreted by a number of cell types including Schwa nn cells, neurons, and oligodendrocytes, NRG transduction signals are media ted by the erbB family of receptor tyrosine kinases, These NRGs may be impo rtant for paracrine or autocrine signaling during development, injury, and the normal functioning of the central nervous system. In this study, we cha racterize the NRGs and erbB receptors expressed by cultured neonatal rat as trocytes, Using immunoblotting protocols With pan-specific antibodies, we i dentified eleven NRG molecular weight isoforms from approximately 16 kDa to 105 kDa in cultured neonatal rat astrocytes, Immunocyotchemistry with isof orm-specific antibodies revealed the expression of both major isoform famil ies (NRG alpha, NRG beta), Additionally, astrocyte-conditioned media contai ned two molecular weight isoforms of NRGs, We detected mRNA expression of N RG alpha and NRG beta in astrocytes by amplifying mRNA transcripts with rev erse transcription polymerase chain reaction. Furthermore, we confirm that cultured astrocytes express all four erbB receptors as detected by immunocy tochemical and immunoblotting techniques, These data indicate that astrocyt es contain and secrete NRGs. (C) 1999 Wiley-Liss,Inc.