Open AccessBrain Capillary Endothelial Cells Express two forms of Erythropoietin Receptor mRNA
Author(s) -
Yamaji Ryoichi,
Okada Tadayuki,
Moriya Maki,
Naito Mikihiko,
Tsuruo Takashi,
Miyatake Kazutaka,
Nakano Yoshihisa
Publication year - 1996
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1996.0494u.x
Subject(s) - erythropoietin , erythropoietin receptor , endothelial stem cell , messenger rna , receptor , recombinant dna , biology , microbiology and biotechnology , cell culture , endocrinology , medicine , chemistry , in vitro , gene , biochemistry , genetics
To study the existence of the erythropoietin receptor (Epo‐R) mRNA in brain capillary endothelial cells, the reverse transcription (RT) PCR was performed using total RNAs from rat brain capillary endothelial cells (RBECs) and MBEC4, which is one of the established mouse brain capillary endothelial cell lines. Southern analysis of the RT‐PCR products indicated that both RBECs and MBEC4 expressed an authentic form of Epo‐R mRNA as a minor form and an intron‐5‐inserted form of Epo‐R mRNA, thus a soluble form of Epo‐R mRNA, as a major form. Furthermore, the effect of recombinant human erythropoietin (rHuEpo) on the DNA synthesis in RBECs was analyzed, rHuEpo showed a dose‐dependent mitogenic action on RBECs as a competence factor. Radioiodinated rHuEpo was bound specifically to RBECs with time, cell number and dose dependencies. Binding studies with 125 I‐rHuEpo showed that RBECs had a single class of receptors with low‐affinity ( K d = 860 pM) and that the number of sites/cell (10300) was abundant. These results suggest that brain capillary endothelial cells express not only an authentic form of Epo‐R but also a soluble form of Epo‐R and that erythropoietin acts directly on brain capillary endothelial cells as a competence factor.