Neural differentiation of the human neuroblastoma cell line IMR32 induces production of a thyrotropin-releasing hormone-like peptide.
The human neuroblastoma cell line IMR32 produces and secretes substantial amounts of TRH-immunoreactivity (TRH-IR) as measured with radioimmunoassay (RIA) using the nonspecific antiserum 4319. It was found that synthesis of TRH-IR is dependent on neural differentiation: under serum-free conditions these cells exhibit neural characteristics as defined by morphological and biochemical standards. After culture for 2-5 days in serum-free medium cells grew large neural processes and expressed neuron-specific markers whereas glial-specific markers were absent. TRH-IR became detectable after 4-8 days serum-free conditions. Northern blot and chromatographic analysis, however, failed to detect proTRH mRNA and authentic TRH in these cells. Moreover, TRH-IR was undetectable in the RIA using TRH-specific antiserum 8880. TRH-IR produced by differentiated cells was retained on a QAE Sephadex A-25 anion-exchange column and thus negatively charged. HPLC analysis showed coelution with the synthetic peptide pGlu-Glu-ProNH2. Study of the mechanisms regulating production of this novel peptide in these cells should further elucidate the role differentiation plays in the synthesis of neuropeptides.
Rondeel
J M
JM
Department of Endocrinology and Reproduction, Erasmus University Medical School, Rotterdam, The Netherlands.
Klootwijk
W
W
Linkels
E
E
de Greef
W J
WJ
Visser
T J
TJ
D015152:Blotting, Northern; D002454:Cell Differentiation / Q000502:physiology; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D009447:Neuroblastoma / Q000473:pathology*; D009474:Neurons / Q000473:pathology*; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives; D011863:Radioimmunoassay; D013973:Thyrotropin-Releasing Hormone / Q000031:analogs & derivatives / Q000378:metabolism*; D013997:Time Factors; D014407:Tumor Cells, Cultured
D013973:Thyrotropin-Releasing Hormone; C059697:pyroglutamyl-glutamyl-proline amide; D011761:Pyrrolidonecarboxylic Acid