• Korean Journal of Head & Neck Oncology
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• v.18 no.2
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• pp.142-149
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• 2002

Objectve : Okadaic acid is a specific inhibitor of serine/threonine protein phosphatase 1 and 2A. In order to know the mechanism of apoptosis induced by okadaic acid, we treated FRTL-5 thyroid cells with okadaic acid and measured the changes of important proteins that are involved in apoptosis. Materials and Methods: We measured caspase 3 activity, $PLC-{\gamma}1$ degradation, the expression of XIAP, cIAP1, cIAP2, and cytochrome c release in okadaic acid-treated FRTL-5 thyroid cells. Results: Okadaic acid-induced caspase 3 activation and $PLC-{\gamma}1$ degradation and apoptosis were dose-dependent with a maximal effect at a concentration of 80 nmol and time-dependent with a maximal effect at 24 hours after treatment. The elevated caspase 3 activity in okadaic acid treated FRTL-5 thyroid cells are correlated with down-regulation of XIAP and cIAP1, but not cIAP2. General and potent inhibitor of caspases, z-VAD-fmk. abolished okadaic acid-induced caspase 3 activity and $PLC-{\gamma}1$ degradation. The release of cytochrome c in okadaic acid-induced FRTL-5 thyroid cells was dose-dependent with a maximal effect at a concentration of 80 nmol. Conclusions: These findings suggest that mechanism of okadaic acid-induced apoptosis is associated with cytochrome c release and increase of caspase 3 activation in FRTL-5 thyroid cells.

• Biomedical Science Letters
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• v.14 no.1
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• pp.59-62
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• 2008

This experiment was performed to study the effect of TSH (thyroid-stimulating hormone) on the expression of endoplasmic reticulum (ER) chaperones in the rat thyrocytes FRTL-5 cells. Although the expressions of ER membrane kinases (ATF6, IRE1 and PERK) were specially enhanced under absence of TSH, no remarkable up- or down regulations of ER chaperones (BiP, CHOP and Calnexin) were detected by TSH. We firstly report here that TSH by dose up-regulated expression of ER membrane kinases in FRTL-5 culture thyrocytes.

• The Journal of Internal Korean Medicine
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• v.26 no.2
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• pp.398-408
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• 2005

Objective: Graves' disease encompasses hyperthyroidism and diffused goiter associated with auto-antibodies to the thyroid stimulating hormone(TSH) receptors. In clinical environment, treatments of Graves' disease have many side effects such as recurrence and hypothyroidism. We've studied the effects of Sipyukmiyukieum on DNA synthesis, cAMP synthesis, and MHC-class II expression of FRTL-5 thyroid cells were studied. Methods: DNA synthesis was investigated by using BrdU staining and cAMP synthesis by ELISA kit, and expression of $interferon-{\gamma}$ activated MHC class II by Flow cytometer. Results: After introduction of Sipyukmiyukieum, significant inhibition of DNA synthesis. cAMP synthesis, and expression of $interferon-{\gamma}$ activated MHC class II of FRTL-5 thyroid cells was observed. Conclusions: Judging from these results, Sipyukmiyukieum has potential as a potent herbal treatment for inhibiting the enlargement of goiter, synthesis of abnormal thyroidal hormones, and autoimmuine responses of Graves' disease.

• The Korean Journal of Physiology and Pharmacology
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• v.8 no.4
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• pp.195-200
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• 2004

Ghrelin is a newly discovered peptide, which is released from the stomach and neurons in the hypothalamic arcuate nucleus (ARC), and potently stimulates growth hormone release and food intake. In the present study, we investigated the effect of ghrelin on $[Ca^{2+}]_i$ in thyroid FRTL-5 cells. Ghrelin (5 nM) increased $[Ca^{2+}]_i$ and TSH (1 unit/l) had an additive effect on $[Ca^{2+}]_i$ when extracellular normal solution was 1.1mM $Ca^{2+}$ containing Coon's modified Ham's F12 medium. When $Ca^{2+}-free$ medium containing 2 mM EGTA replaced the above normal solution, ghrelin also induced a similar rise in $[Ca^{2+}]_i$. In the middle of $[Ca^{2+}]_i$ increment by ghrelin, nifedipine $(1\;{\mu}M)$, nickel $(100\;{\mu}M)$ and $La^{3+}\;(100\;{\mu}M)$ had no effect on $[Ca^{2+}]_i$. After endoplasmic reticulum was depleted by cyclopiazonic acid $(CPA;10\;{\mu}M)$, ghrelin caused no visible change on $[Ca^{2+}]_i$ in $Ca^{2+}-free$/2 mM EGTA solution. These results suggest that ghrelin can increase $[Ca^{2+}]_i$ through endoplasmic reticulum in thyroid FRTL-5 cells.

• Journal of Life Science
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• v.9 no.1
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• pp.76-83
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• 1999

Mammalial expression vectors containing GRP94, BiP, ERp72, and PDI, were introduced into FRTL5 cells. Transfected cells were selected by neomycin resistance for exogenously overexpressed proteins in the ER. The use of a reducible cross-linker, DSP, markedly improved the ability to detect noncovalent interactions of PDI, BiP and GRP94 with newly-synthesized thyroglobulin. Under normal conditions, GRP94 was found to associate transiently with early Tg folding intermediates, displaying interaction kinetics similar to those reported for another ER chaperones of BiP.

• Korean Journal of Pharmacognosy
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• v.36 no.2 s.141
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• pp.88-92
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• 2005

Apoptosis plays an important role in autoimmune chronic (Hashimoto's) thyroiditis, a disorder that often results in hypothyroidism. The goal of this study was to induce apoptosis by the combination of inflammatory cytokines, interferon $(IFN)-{\gamma}$ and tumor necrosis factor $(TNF)-{\alpha}$, and to investigate a potential role of medicinal plants in the thyroid follicular cells (FRTL) in vitro. The apoptosis was evaluated by cellular viability, DNA fragmentation, and terminal deoxynucleotidyl transferase-mediated deoxy-UTP nick end labeling (TUNEL) assay. Extract of Gamgung-tang (GGT, Glycyrrhizae Radix, black beans, Angelicae Radix, and Cnidii Rhizoma) $(0.3{\sim}9.0mg/ml)$ was shown to maintain the viability of cells treated with $IFN-{\gamma}(100U/ml)$ and $TNF-{\alpha}$ (0.5 ng/ml). FRTL cells were found to undergo DNA fragmentation with the inflammatory cytokines. The extract of GGT inhibited DNA fragmentation in dose-dependent manner. The cells with TUNEL-positive nuclei were detected with $IFN-{\gamma}$ and $TNF-{\alpha}$ treatment. The number of TUNEL-positive cells decreased with the treatment of extract of GGT. These results indicate that medicinal plants inhibit the occurrence of apoptosis in thyroid follicular cells, therefore, may have therapeutic potential in the treatment of autoimmune chronic thyroiditis.

• Journal of Life Science
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• v.10 no.2
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• pp.150-156
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• 2000

This experiment was performed to evaluate the effect of TSH (thyroid-stimulating) on the ERp29 (endoplasmic reticulum resident 29 kDa protein) gene expression in the rat thyrocytes of FRTL-5 cells. Although ERp29 mRNA was constantly expressed, its expression began to increase remarkably from 10-9 M TSH. and its maximum expression was at 5×10-9 M TSH (about 3.5 fold). On the other hand, the effect of TSH on the abundance of ERp29 mRNA started within 6 h, and peaked at 8 h (about 2.5 fold). Actinomycin D (transcription inhibitor) strongly blocked this effect while cycloheximide (translation inhibitor) did not. The half-life of ERp29 mRNA was about 4.5 h in the presence or absence of TSH that was not affected by the stability of ERp29 mRNA. The effect of TSH on the ERp29 gene expression was specific, while other growth factors (transfferin, insulin, and hydrocortisone) did not alter its expression. Our data indicate for the first time that the expression of ERp29 is regulated transcriptionally by TSH in the thyrocytes.

• Journal of Life Science
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• v.22 no.2
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• pp.281-284
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• 2012

This study demonstrated that upregulation of gene expression of endoplasmic reticulum (ER) stress chaperones (Bip, ERp29, calnexin, and PDI), ER stress sensors (PERK, ATF6, and Ire1), and cAMP phosphodiesterase 7A1 (cAMP PDE7A1) was induced by ER stresses in FRTL5 cells. While removing A23187 from the culture medium restored upregulation of cAMP PDE7A1 gene expression, removal of thapsigargin did not recover its expression. In addition, cAMP PDE7A1 gene expression was strongly inhibited by treatment with A23187 combined with thyroid stimulating hormone (TSH). The results are the first to show that ER stress induces cAMP PDE7A1 gene expression.

• Journal of Life Science
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• v.17 no.7 s.87
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• pp.1023-1025
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• 2007

Ajuba is a number of proteins containing cytosolic LIM domain. Its function may provide a new pathway whereby cell-cell adhesive events are transmitted to the nucleus to regulate cell proliferation and differentiation decisions. Here, Ajuba gene expression was investigated its molecular properties associated with endoplasmic reticulum (ER) stresses (tunicamycin, DTT, A23187 and BFA) which induced remarkable ex-pression of Ajuba mRNA. The mRNA half life of Ajuba was also determined, its half life of Ajuba mRNA in FRTL-5 cells was approximately 2 hr after the initial translation. Although the obvious bioligical function of Ajuba is not clear, on the base of the results, Ajuba gene expression is deeply associated with ER stresses.

• Journal of Life Science
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• v.20 no.8
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• pp.1249-1253
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• 2010

Sericin is a type of high molecular weight water-soluble glycoprotein surrounding fibroin (silk protein) that has been used as a cell culture supplement and accelerates cell proliferation in various serum-free media. The purpose of this study was to investigate the enhancing effect of thyroglobulin (Tg) secretion by sericin in thyrocytes, FRTL-5 cells. While Tg-mRNA expression was not enhanced, a secreted form of Tg was obviously increased by sericin. In this status, expression of both endoplasmic reticulum (ER) molecular chaperones (Bip & calreticulin) and ER membrane proteins (IRE1, PERK & ATF6) was enhanced. The proximal step of IRE1, XBP1 mRNA splicing was slightly detected however, the proximal step of PERK, phosphorylation of $eIF2{\alpha}$, was changeless. In addition, sericin enhanced cell viability by the MTT assay. The above results showing the ability of sericin to promote protein production demonstrated its potential usefulness as a new biomaterial.