Glycosylation of thyroglobulin secreted by porcine cells cultured in chamber system: thyrotropin controls the number of oligosaccharides and their anionic residues.

Desruisseau, Sylvie; Franc, Jean‐Louis; Gruffat, Dominique; Chabaud, Odile

doi:10.1210/endo.134.4.8137731

Cited by 14 publications

(6 citation statements)

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“…4). This specific activity was increased sixfold by TSH in the absence of serum and increased twofold in the presence of 10% serum as previously described (Desruisseau et al, 1994). The specific activity of 3H-mannose-labeled Tg was also sixfold increased when insulin was present simultaneously with TSH, i.e., 12-fold the basal level.…”

Section: Regulation Of Thyroglobulin Accumulation In Apical Mediumsupporting

confidence: 81%

“…Therefore, if the intracellular mannose concentration was enhanced, the specific activity of the precursor was consequently modified under hormonal stimulation in the absence of serum. However, we observed that in the presence of serum the specific activity of intracellular mannose was not increase by TSH (Desruisseau et al, 1994). Nevertheless, the difference of TSH effect observed with serum and without serum may be due to a difference of specific activity of intracellular precursor.…”

Section: Discussioncontrasting

confidence: 60%

“…Thus TSH and insulin effects appeared to be additive as shown above for the other steps of synthesis. Previous results in the presence of serum (Desruisseau et al, 1994) showed that TSH increased only the number of oligosaccharides bound to Tg molecules. TSH and insulin could not increase the number of oligosaccharide chains per Tg molecule more than tenfold in the absence of serum because potential glycosylation sites on Tg molecules were not sufficient (Malthiery et al, 1989).…”

Section: Discussionmentioning

confidence: 82%

“…Anionic charges could be due to sialic acid, sulfate, or phosphate. Recent work (Desruisseau et al, 1994) showed that sialic acid content was not very different between Tg molecules secreted by TSH-stimulated and unstimulated cells cultured in the presence of 10% serum. However, Ronin et al (1986) reported an increase in sialic acid in porcine Tg under TSH stimulation in different culture conditions and in serum-free medium.…”

Section: Discussionmentioning

confidence: 97%

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Hormonal regulation of some steps of thyroglobulin synthesis and secretion in bicameral cell culture

Desruisseau

Alquier

Depétris

et al. 1994

Journal Cellular Physiology

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Porcine thyroid cells were cultured for 15 days on porous bottom chambers with or without different mixtures of hormones added to serum-free basal medium. Assays with 10% serum were also performed for comparison with previously published results. The effects of the hormones, particularly insulin, TSH and hydrocortisone, were studied on total RNA content, thyroglobulin mRNA level, the amount of thyroglobulin secreted into the apical medium and on glycosylation. Insulin and TSH similarly increased the total RNA content, and their effects were additive. Thyroglobulin mRNA content was increased twofold by insulin and threefold by TSH. When they were added simultaneously, the maximal level of thyroglobulin mRNA was reached, showing that TSH and insulin effects on thyroglobulin gene expression were additive. Hydrocortisone alone did not modify total RNA or thyroglobulin mRNA content but the hormone amplified total RNA when insulin and TSH were present together. The basal level of thyroglobulin secreted into the apical medium was increased threefold by insulin and fourfold by TSH. The effects of these two hormones added together appeared to be additive. Hydrocortisone had no effect alone or even when combined with insulin or TSH. However, when the three hormones were added together, the hormonal response was amplified. TSH effect and insulin effect on the incorporation of 3H-mannose into thyroglobulin as well as on the anionic residue content of the molecule were additive.

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Section: Regulation Of Thyroglobulin Accumulation In Apical Mediumsupporting

confidence: 81%

Section: Discussioncontrasting

confidence: 60%

Section: Discussionmentioning

confidence: 82%

Section: Discussionmentioning

confidence: 97%

See 2 more Smart Citations

Hormonal regulation of some steps of thyroglobulin synthesis and secretion in bicameral cell culture

Desruisseau

Alquier

Depétris

et al. 1994

Journal Cellular Physiology

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show abstract

“…Glycosylation has also been shown to be modulated by TSH in cultured thyroid cells (27,28). In primary culture of porcine thyroid cells, TSH increased the number of oligosaccharide side chains borne by Tg without modifying the relative distribution of the various types of oligosaccharide structures (29). In FRTL-5 cells it appeared rather that TSH decreased (30) or increased (31) the number of oligosaccharide side chains.…”

Section: Discussionmentioning

confidence: 97%

N-Glycans Modulate in Vivo and in Vitro Thyroid Hormone Synthesis

Mallet

Lejeune

Baudry

et al. 1995

Journal of Biological Chemistry

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Thyroglobulin (Tg) is the substrate for thyroid hormone biosynthesis, which requires tyrosine iodination and iodotyrosine coupling and occurs at the apical membrane of the thyrocytes. Tg glycoconjugates have been shown to play a major role in Tg routing through cellular compartments and recycling after endocytosis. Here we show that glycoconjugates also play a direct role in hormonosynthesis. The N-terminal domain (NTD; Asn 1 -Met 171 ) of human Tg, which bears the preferential hormonogenic site, brings two N-glycans (Asn 57 and Asn 91 ). NTD preparations were purified from Tg with low and mild iodine content in vivo and from poorly iodinated Tg after in vitro iodination and coupling. NTD separated from poorly iodinated Tg was also submitted to iodination and coupling after desialylation and deglycosylation. The various NTD isoforms were analyzed for their N-glycan structures and hormone contents. Our results show that 1) in vivo as well as in vitro unglycosylated isoforms did not synthesize hormones, whereas fully or partially (at Asn 91 ) glycosylated isoforms did; 2) high mannose type structures enhanced the hormone content; and 3) desialylation did not affect in vitro hormone synthesis. Evidence of a direct involvement in hormonosynthesis adds to the role of N-glycans in Tg function and opens the way to new mechanisms for regulation (e.g. TSH modulation of N-glycan) or alteration (e.g. Asn 91 mutation) of thyroid hormone synthesis.

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Thyrotropin chronically regulates the pool of thyroperoxidase and its intracellular distribution: A quantitative confocal microscopic study

Penel¹,

Gruffat²,

Alquier³

et al. 1998

J. Cell. Physiol.

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The regulation of thyroperoxidase (TPO) expression and of its intracellular distribution was studied in porcine thyroid cells cultured on porous bottom filters. Cells were cultured for 18 days in the absence or in the presence of thyrotropin (TSH) and with or without iodide. Microsomes were purified and analyzed by electrophoresis. TPO was detected by immunoblotting with polyclonal anti-porcine TPO antibodies and quantified by scanning the bands. The amount of TPO was increased 2-fold by TSH. High concentrations of iodide (1-50 microM, added daily) decreased the level of TPO. Confocal microscopy served to determine the intracellular localization of TPO and its quantitative distribution. Intracellular and surface-located TPO was detected by fluorescein-labeled antibodies on saponin-treated cells. Quantitative confocal microscopy showed that TSH increased the total amount of TPO 2-fold as for immunoblotting. The highest amount of TPO was found in the perinuclear area and between the nucleus and the Golgi apparatus. Only 4% of TPO was present on the apical surface and about 1% on the basolateral membrane; the remainder (about 95%) was inside the cells. TSH did not change these relative contents. TSH modified the intracellular distribution of the enzyme, increasing the TPO pool from the perinuclear area to apical membrane. This domain could be a site of storage of TPO. Adding a physiological concentration of iodide (0.5 microM, daily) did not influence the intracellular distribution of TPO. We concluded that chronic TSH stimulation 1) increased 2-fold the pool of TPO but did not change the relative proportion of TPO inside the cells and on the apical surface, and 2) modified the intracellular distribution of vesicular TPO, the major part of which was accumulated in the perinuclear and cytoplasmic area under the subapical domain of the polarized cells.

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Glycosylation of thyroglobulin secreted by porcine cells cultured in chamber system: thyrotropin controls the number of oligosaccharides and their anionic residues.

Cited by 14 publications

References 1 publication

Hormonal regulation of some steps of thyroglobulin synthesis and secretion in bicameral cell culture

Hormonal regulation of some steps of thyroglobulin synthesis and secretion in bicameral cell culture

N-Glycans Modulate in Vivo and in Vitro Thyroid Hormone Synthesis

Thyrotropin chronically regulates the pool of thyroperoxidase and its intracellular distribution: A quantitative confocal microscopic study

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