Corticotropin releasing factor binding protein (CRF-BP) is expressed in neuronal and astrocytic cells.
Corticotropin releasing factor (CRF) binding protein (CRF-BP) was measured in media and cell lysates of primary rat astrocytes, microglia and neurons with the use of a ligand immunoradiometric assay (LIRMA). A low basal level of CRF-BP was detected in the media and cell lysates from primary neuronal and astrocyte cells after 48 h in culture. No basal expression of CRF-BP was detected in cell lysates or media from primary microglial cultures. The CRF-BP expressed in cultured astrocytes and neurons had the same pharmacological characteristics as the human recombinant molecule. After forskolin, IBMX or forskolin/IBMX treatment, a robust increase in secreted CRF-BP levels in the media from astrocytes and neurons, but not microglia, was observed. An increase in CRF-BP-like immunoreactivity in cell lysates was also observed after IBMX/forskolin treatment. In situ hybridization analysis revealed that CRF-BP mRNA was increased in primary cultured astrocytes after IBMX/forskolin stimulation suggesting that regulation was at the level of gene transcription. 'Axon sparing' lesions produced with 0.12 M quinolinic acid in PBS injected intracerebrally (unilaterally into dorsal hippocampus) resulted in loss of CRF-BP expression in neurons. These data provide evidence for the differential localization and regulation of CRF-BP in different cell types in brain and suggest that CRF-BP expression may be locally increased in disease states associated with astrocytosis and gliosis.
Behan
D P
DP
Neurocrine Biosciences Inc., San Diego, CA 92121, USA.
Maciejewski
D
D
Chalmers
D
D
De Souza
E B
EB
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000818:Animals; D001253:Astrocytes / Q000737:chemistry*; D002352:Carrier Proteins / Q000032:analysis*; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology; D015592:Immunoradiometric Assay; D017403:In Situ Hybridization; D017628:Microglia / Q000737:chemistry; D009419:Nerve Tissue Proteins / Q000032:analysis*; D009474:Neurons / Q000737:chemistry*; D051381:Rats; D017207:Rats, Sprague-Dawley
D002352:Carrier Proteins; D009419:Nerve Tissue Proteins; C067133:corticotropin releasing factor-binding protein; D005576:Colforsin; D015056:1-Methyl-3-isobutylxanthine