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Transcription‐Independent Activation of Ornithine Decarboxylase Activity by Heparin in Cloned Cerebral Endothelial Cells
Author(s) -
Bauer H.,
Amberger A.,
Bauer H. C.,
Webersinke G.,
Zach O.,
Olson J. W.,
Hennig B.
Publication year - 1993
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1993.tb03316.x
Subject(s) - ornithine decarboxylase , heparin , biology , cell growth , endothelial stem cell , dna synthesis , cell culture , microbiology and biotechnology , growth factor , biochemistry , enzyme , dna , in vitro , genetics , receptor
Heparin, a highly sulfated glycosaminoglycan, is known to be obligatory for long‐term endothelial cell cultures; it potentiates the mitogenic activities of endothelial cell growth factors and prolongs the replicative life span of the cells. Here we have shown that besides its growth factor‐supportive role, heparin exerts a specific action on cerebral capillary endothelial cells (cECs), unrelated to serum or growth factors, by increasing activity of ornithine decarboxylase (ODC; EC 4.1.1.17) in these cells. For our experiments we have used two different types of cloned cECs: type I cECs, grown in the presence of endothelial cell growth factor and heparin, and type II cECs, usually cultivated without growth factors. Heparin action on ODC activity was shown to be dose dependent within the range of 1–100 μg/ml. Increasing concentrations of or depletion of endothelial cell growth factor from type I cultures had no effect on ODC activity. The increase in enzyme activity was highest after 30 min to 1 h of heparin treatment. As evidenced by northern analysis, the heparin‐mediated enhancement of ODC activity was not accompanied by changes of ODC mRNA levels. Studies of DNA replication revealed that in the absence of heparin‐binding growth factors, heparin did not affect the proliferative activity of cloned cECs.