Thyroid hormone regulates the expression of alpha-internexin in neurons in culture.
Maternal hypothyroidism in the rat compromises alpha-internexin (alpha-IN) expression in early fetal brain. We have therefore examined whether 3,5,3'-triiodothyronine (T3) regulates alpha-IN expression in fetal brain neurons in culture. Cells expressed transcripts encoding T3 nuclear receptor isoforms in a T3-independent manner. alpha-IN protein abundance was increased in cultures treated with 0.1 and 1 nM T3 for 20 h (177 and 185% control, respectively) and in cultures treated with 1 nM T3 for 40 h (131% control). alpha-IN transcript abundance was unaffected by T3 treatment. In conclusion, T3 at a physiological level, stimulates alpha-IN protein, but not mRNA, levels in early differentiating neurons in culture. This supports the hypothesis that maternal thyroid hormone directly regulates early neuronal differentiation.
Sampson
David
D
Division of Molecular Endocrinology, University College London Medical School, Mortimer Street, London W1N 8AA, UK.
Pickard
Mark
M
Evans
Ian
I
Leonard
Andrew
A
Sinha
Arun
A
Ekins
Roger
R
D000818:Animals; D015153:Blotting, Western; D001921:Brain / Q000166:cytology; D002352:Carrier Proteins / Q000096:biosynthesis*; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis / Q000235:genetics; D005260:Female; D007150:Immunohistochemistry; D007381:Intermediate Filament Proteins; D008297:Male; D008858:Microscopy, Phase-Contrast; D009419:Nerve Tissue Proteins / Q000096:biosynthesis / Q000235:genetics; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D011247:Pregnancy; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D011988:Receptors, Thyroid Hormone / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013963:Thyroid Hormones / Q000494:pharmacology*; D014284:Triiodothyronine / Q000494:pharmacology
D002352:Carrier Proteins; D007381:Intermediate Filament Proteins; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D011988:Receptors, Thyroid Hormone; D013963:Thyroid Hormones; C046643:alpha-internexin; D014284:Triiodothyronine; D004247:DNA