Characterization of TGF-β1 type II receptor expression in cultured cortical astrocytes

The transforming growth factor-βs (TGF-βs) comprise a family of pleiotropic members that signal through two types of serine/threonine kinase receptors, named TGFRI (TGF-β type I receptor) and TGFRII (TGF-β type II receptor). We previously demonstrated that cortical neurons increase the astrocyte maturation marker, glial fibrillary acidic protein (GFAP), and thus, astrocyte differentiation, by inducing TGF-β1 secretion by astrocytes in vitro. Although TGF-β receptor expression has been described in different brain regions and cell types, their localization is still a subject of discussion. In the present work, we analyzed TGFRII expression in cultured cortical astrocytes from embryonic and newborn animals by immunocytochemistry, Western blot, and reverse transcriptase-polymerase chain reaction (RT-PCR). We report for the first time expression of TGFRII in embryonic glia. TGFRII immunostaining was punctual and spread throughout the cellular membrane of embryonic and newborn astrocytes. Western blot and RT-PCR assays revealed similar levels of the receptor in astrocytes from different ages. Identification of TGFRII in embryonic astrocytes is novel and might point to the multipotent precursor cell, radial glia, as a potential target for TGFβ1 during astrocyte development. © 2006 Society for In Vitro Biology.