Differential regulation of granulocyte-macrophage colony-stimulating factor mRNA and protein expression in human thyrocytes and thyroid-derived fibroblasts by interleukin-1 alpha and tumor necrosis factor-alpha.
In this study, we provide the first report on the production of granulocyte-macrophage colony-stimulating factor (GM-CSF) by human thyroid epithelial cells. Primary cultures of highly purified thyrocytes and thyroid-derived fibroblasts (n = 3) and three thyroid anaplastic and one largely papillary carcinoma cell lines were exposed to different potent GM-CSF stimulators, employing interleukin 1 alpha (Il-1 alpha) and tumour necrosis factor-alpha (TNF-alpha). Cytokine mRNA levels were monitored by semi-quantitative reverse transcriptase-PCR including an internal heterologous competitor fragment after 3, 6 and 18 h of culture. Culture supernatants were assayed for GM-CSF using a highly sensitive ELISA (detection limit < or = 0.5 pg/ml) after 24 h. Basal GM-CSF mRNA expression was higher in fibroblasts and SW 1736 cells compared with thyrocytes, C 634, 8505 C and HTh 74 cells. GM-CSF was spontaneously secreted by fibroblasts (means +/- S.E.M.; 43 +/- 15 pg/ml), SW 1736 (59 +/- 4 pg/ml), HTh 74 (34 +/- 4 pg/ml) and C 643 cells (12 +/- 1 pg/ml) but not by thyrocytes and 8505 C cells. Treatment with Il-1 alpha (10 U/ml) resulted in a marked increase of GM-CSF mRNA within 3 h and an increase or induction of protein expression in thyrocyte (2350 +/- 214 pg/ml), fibroblast (5242 +/- 1400 pg/ml), SW 1736 (20016 +/- 280 pg/ml) and C 643 cultures (1285 +/- 79 pg/ml). Stimulation with TNF-alpha (10 U/ml) yielded divergent results. No significant increase of GM-CSF mRNA or protein expression was found in thyrocytes although TNF-alpha receptor expression in these cells is well documented. Stimulation with TNF-alpha resulted in an increased GM-CSF production in fibroblasts (361 +/- 14 pg/ml), HTh 74 (148 +/- 51 pg/ml) and SW 1736 cultures (235 +/- 43 pg/ml). TSH (10 mU/ ml) did not stimulate GM-CSF secretion in thyrocytes and HTh 74 cells, both expressing the TSH receptor. Phorbol 12-myristate 13-acetate (10 ng/ml) enhanced GM-CSF mRNA and protein levels in all cell types investigated. Our data suggest that both thyrocytes and fibroblasts synthesize GM-CSF in response to Il-1 alpha, but only fibroblasts respond to TNF-alpha with a significant increase in GM-CSF. Anaplastic thyroid carcinomas are potential GM-CSF producers.
Aust
G
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Department of Internal Medicine III, University of Leipzig, Germany.
Hofmann
A
A
Laue
S
S
Ode-Hakim
S
S
Scherbaum
W A
WA
D002277:Carcinoma / Q000276:immunology; D002478:Cells, Cultured; D005347:Fibroblasts / Q000276:immunology*; D005786:Gene Expression Regulation / Q000187:drug effects*; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology; D008875:Middle Aged; D015846:Monokines / Q000494:pharmacology*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D013961:Thyroid Gland / Q000166:cytology / Q000276:immunology*; D013964:Thyroid Neoplasms / Q000276:immunology; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D007375:Interleukin-1; D015846:Monokines; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D016178:Granulocyte-Macrophage Colony-Stimulating Factor