• Molecules and Cells
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• v.38 no.6
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• pp.548-561
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• 2015

By combining conventional single cell analysis with flow cytometry and public database searches with bioinformatics tools, we extended the expression profiling of thymic stromal cotransporter (TSCOT), Slc46A2/Ly110, that was shown to be expressed in bipotent precursor and cortical thymic epithelial cells. Genome scale analysis verified TSCOT expression in thymic tissue- and cell type- specific fashion and is also expressed in some other epithelial tissues including skin and lung. Coexpression profiling with genes, Foxn1 and Hoxa3, revealed the role of TSCOT during the organogenesis. TSCOT expression was detected in all thymic epithelial cells (TECs), but not in the $CD31^+$endothelial cell lineage in fetal thymus. In addition, ABC transporter-dependent side population and Sca-$1^+$ fetal TEC populations both contain TSCOT-expressing cells, indicating TEC stem cells express TSCOT. TSCOT expression was identified as early as in differentiating embryonic stem cells. TSCOT expression is not under the control of Foxn1 since TSCOT is present in the thymic rudiment of nude mice. By searching variations in the expression levels, TSCOT is positively associated with Grhl3 and Irf6. Cytokines such as IL1b, IL22 and IL24 are the potential regulators of the TSCOT expression. Surprisingly, we found TSCOT expression in the lung is diminished in lung cancers, suggesting TSCOT may be involved in the suppression of lung tumor development. Based on these results, a model for TEC differentiation from the stem cells was proposed in context of multiple epithelial organ formation.

• The Korean Journal of Cytopathology
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• v.2 no.1
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• pp.36-42
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• 1991

We report 4 cases of malignant thymoma which were composed of 2 cases of invasive thymoma and 2 cases of thymic carcinoma. The cytologic findings of invasive thymoma were similar to those of benign thymoma. The distinctive cytologic features of thymic carcinoma were necrotic background, irregular clusters and individually scattered arrangement of anaplastic epithelial cells, and some scattered mature small lymphocytes. These findings may be found in the Hodgkin's lymphoma, seminoma, and metastatic squamous ceil carcinoma, undifferentiated carcinoma, and large ceil carcinoma of the lung. But, the feature of irregular clustering of anaplastic epithelial cell haying scanty cytoplasm was different from Hodgkin's lymphoma and seminoma. Clinical and radiologic findings as well as cytologic finding were helpful in differential diagnosis of thymic carcinoma from metastatic carcinoma.

• Journal of Life Science
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• v.33 no.8
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• pp.612-622
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• 2023

T-cell deficiency may occur in various clinical conditions including congenital defects, cell/organ transplantation, HIV infection and aging. In this regard, the development of artificial thymus has recently been attracting much attention. To achieve this aim, the development of techniques for 3D culture of thymic stromal cells is necessary because thymocytes grown only in a 3D thymic microenvironment can be differentiated fully to become mature, immunocompetent T cells; the same cannot be achieved for thymocytes grown in 2D. This study aimed to develop a nanotechnology-based 3D culture technique using polymeric scaffolds for thymic epithelial cells (TECs), the main component of thymic stromal cells. Scanning electron microscopic observation revealed that the pores of both PCL and PCL/PLGA scaffolds were filled with TECs. Interestingly, TECs grown in 3D on polydopamine-coated scaffolds exhibited enhanced cell attachment and proliferation compared to those grown on non-coated scaffolds. In addition, the gene expression of thymopoietic factors was upregulated in TECs cultured in 3D on polydopamine-coated scaffolds compared to those cultured in 2D. Taken together, the results of the present study demonstrate an efficient 3D culture model for TECs using polymeric scaffolds and provide new insights into a novel platform technology that can be applied to develop functional, biocompatible scaffolds for the 3D culture of thymocytes. This will eventually shed light on techniques for the in vitro development of T cells as well as the synthesis of artificial thymus.

• Journal of Yeungnam Medical Science
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• v.27 no.2
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• pp.98-104
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• 2010

Primary anterior mediastinal neoplasms comprise a diverse group of tumors and account for 50% of all mediastinal masses. Thymic epithelial neoplasm are most common and classified into thymoma, invasive thymoma, and thymic carcinoma. Neuroendocrine differentiation of thymic epithelial neoplasm are rare malignancies. Germ cell tumor (GCT) is second most common anterior mediastinal tumor and most of them are mature cystic teratoma. Malignant mediastinal GCT are rare than benign. Primary thoracic lymphoma is rare than thoracic involvement of systemic lymphoma and most common location of primary thoracic lymphoma is anterior mediastinum. The clinical and radiologic appearance of the most common masses are reviewed.

• IMMUNE NETWORK
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• v.15 no.3
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• pp.111-120
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• 2015

Dendritic cells (DCs) play a significant role in establishing self-tolerance through their ability to present self-antigens to developing T cells in the thymus. DCs are predominantly localized in the medullary region of thymus and present a broad range of self-antigens, which include tissue-restricted antigens expressed and transferred from medullary thymic epithelial cells, circulating antigens directly captured by thymic DCs through coticomedullary junction blood vessels, and peripheral tissue antigens captured and transported by peripheral tissue DCs homing to the thymus. When antigen-presenting DCs make a high affinity interaction with antigen-specific thymocytes, this interaction drives the interacting thymocytes to death, a process often referred to as negative selection, which fundamentally blocks the self-reactive thymocytes from differentiating into mature T cells. Alternatively, the interacting thymocytes differentiate into the regulatory T (Treg) cells, a distinct T cell subset with potent immune suppressive activities. The specific mechanisms by which thymic DCs differentiate Treg cells have been proposed by several laboratories. Here, we review the literatures that elucidate the contribution of thymic DCs to negative selection and Treg cell differentiation, and discusses its potential mechanisms and future directions.

• Korean Journal of Head & Neck Oncology
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• v.29 no.2
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• pp.68-70
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• 2013

Thymoma is the most common anterior mediastinal mass in adult, and arises from thymic epithelial cells which includes consists various proportions of epithelial and lymphocytic aspect. Thymic epithelial cell arises from the ventral wings of the third and fourth branchial pouches in the embryo, and these cells are considered tumorous condition of thymoma. Surgical resection is main treatment of thymoma. And adjuvant chemotherapy or radiation is considered due to postoperative pathologic diagnosis. We experienced a tumor which located from left anterior neck along superior mediastinum on chest radiograph incidentally and diagnosed parathyroid adenoma clinically. After surgical removal, final pathologic report was thymoma. Here, we present the case with a review of the related literatures.

• IMMUNE NETWORK
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• v.4 no.2
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• pp.81-87
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• 2004

Background: In the thymus, developing thymocytes continually interact with thymic epithelial cell components. Self MHC restriction of mature T cells are imposed in the thymus through interaction of immature double positive thymocytes and thymic cortical epithelial cells. The site of negative selection, however, is a matter of debate. Through systemic injection of anti-TCR antibody or antigenic peptides, investigators suggested that most of the negative selection occurs in the thymic cortex. But the requirements for negative selection, i.e cellular counterparts and costimulatory molecules are more available in the medulla or cortico-medullary junction rather than in the thymic cortex. Methods: The direct and indirect pathways of thymocyte death after systemic anti-TCR antibody injection were separated through several experimental systems. B6 mice were either adrenalectomized or sham-adrenalectomized to evaluate the role of endogenous glucocorticoids from adrenal gland. Role of TNF were evaluated through using TNF receptor double knockout mice. Results: We found that without indirectly acting mediators such as $TNF-\alpha$ or corticosteroid, double positive thymocyte death were minimal by systemic injection of anti-TCR antibody in TNF receptor double knockout neonatal mice. Also by analyzing neonatal wild-type mice with adoptively transferred mature T cells, only peripheral activation of mature T cells could induce extensive double positive thymocyte death. Conclusion: Thus, systemically injected anti-TCR antibody mediated thymocyte death are mostly induced through indirect pathway.

• Journal of Animal Science and Technology
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• v.57 no.10
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• pp.30.1-30.4
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• 2015

The present study was aimed to study the light and electron microscopic studies of thymic Hassall's corpuscles was done in various age groups of Nandanam Chicken ranging from day-old to forty weeks. Hassall's corpuscles are special, unique structures present in thymic medulla and also in the cortex of all the age groups of Nandanam chicken (from hatch to forty weeks) in the present study. Size of the Hassall's corpuscles in the medulla is larger than the ones present in the cortical region of thymus. The Hassall's corpuscles are made up of structureless eosinophilic mass surrounded by concentrically arranged reticuloepithelial cells. Under electron microscope, the Hassall's corpuscles were composed of reticuloepithelial cells interconnected by many desmosomes. The epithelial cells had abundance of cytoplasmic fibrils and desmosomes with few mitochondria and ribosomes. The nucleus was oval or round which was slightly indented. The centre of the Hassall's corpuscles was appeared either solid or cystic. The cystic corpuscles had cell debris within the cyst lumen.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.26 no.2
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• pp.133-136
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• 2015

Spindle epithelial tumor with thymus-like differentiation (SETTLE) is an extremely rare type of thyroid tumor, with spares reports on its clinical course. SETTLE is derived from branchial pouch or thymic remnants, and classified as a low grade, malignant neoplasm due to its indolent growth and tendency to develop delayed metastasis. Therefore, stringent initial workups and long-term follow-up are required to prevent misdiagnosis. We present a case of recurrent spindle epithelial tumor with thymus-like differentiation (SETTLE) in the glottis of 57 year-old male patient, who had a history of surgical excision for the SETTLE from the thyroid gland 5 years ago. Transoral CO2 laser surgery was performed to remove the glottic tumor and there was no evidence of local recurrence at 11 months postoperatively.

• Development and Reproduction
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• v.15 no.4
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• pp.373-383
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• 2011

Tributyltin (TBT) is one of endocrine disrupters which are known as having similar function to sex steroid hormone inducing apoptosis in various tissues of rodents. Recently, it has been reported that TBT induces apoptosis in thymus causing the decreased thymic function, but little is known about the mechanism. To elucidate the mechanism, three-week-old SD female rats were orally administrated with TBT 1, 10, and 25 mg per body weight (kg) and sesame oil as a control for 7 days. On day 8, the thymi were obtained and weighed, and then the number of thymocytes was counted. We also performed H&E staining, TUNEL assay, and Annexin V flow cytometric analysis to examine the apoptosis rates and the structure in the thymus. Next, we investigated the adipogenesis and apoptosis-related mRNA expression levels in the thymi by real-time PCR. The thymic weight and the number of thymocytes were decreased by TBT in a dose-dependent manner. As a result of the H&E staining, the boundary between cortical and medullary area was blurred in the thymi of TBT treated rats compared to those of controls. In the results of TUNEL assay and Annexin V flow cytometric analysis, apoptosis rates in the thymus were increased after TBT treatment. The expression levels of thymic epithelial cell marker genes such as EVA, KGF, AIRE, and IL-7 were significantly decreased in the thymi of TBT treated rats, but $PPAR{\gamma}$, aP2, PEPCK, and CD36 were significantly increased. The expression of $TNF{\alpha}$ and TNFR1 as apoptosis-related genes also was significantly increased after TBT treatment. The present study demonstrates that TBT can increase the expression of adipogenesis and apoptosis-related genes leading to apoptosis in the thymus. These results suggest that the increased adipogenesis of thymus by TBT exposure might induce apoptosis in the thymus resulting in a loss in thymic immune function.