Tributyltin에 의한 흰쥐 흉선 내 상피세포의 지방세포 유도와 세포자연사 증가
Tributyltin Induces Adipogenesis and Apoptosis of Rat Thymic Epithelial Cells
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성 호르몬과 유사한 기능을 하는 것으로 알려진 내분비교란물질은 흰쥐 흉선세포에 세포자연사를 일으켜 흉선의기능을 감소시키는 것으로 보고되고 있으나, 그 작용 기전에 대해서는 잘 알려져 있지 않다. 따라서 본 연구에서는 내분비교란물질 중 하나인 Tributyltin(TBT)를 흰쥐에 투여한 후 흉선의 상피세포가 지방세포로 분화되는지를 조사하고, 이로인한 T 세포의 세포자연사와 연관성을 조사함으로써 TBT가 흉선기능에 미치는 영향을 알아보고자 하였다. 3주령 된 암컷 흰쥐에 각각 TBT 1, 10, 25 ㎎/㎏/day를 1주일 동안 경구 투여한 후, 흉선을 획득하여 무게와 세포 수를 측정하였고,파라핀 절편으로 H&E 염색, TUNEL 분석을 수행하였다. 또한 real-time PCR 방법으로 상피세포 표지 유전자들, 지방세포유도 유전자들과 세포자연사 관련 유전자들을 비교 분석하였으며, 유세포 분석기를 통해 세포자연사 정도를 조사하였다. 흉선의 무게와 세포 수는 대조군과 비교하여 TBT의 농도가 높을수록 유의하게 감소하였다. H&E 염색 결과, TBT의 농도가 증가할수록 흉선의 크기가 감소하고 피질과 수질의 경계가 흐려짐을 관찰하였다. TUNEL 염색 결과에서는 대조군에 비해 TBT를 투여한 군에서 세포자연사가 증가하였으며,유세포 분석결과에서도 TBT 농도 의존적으로 세포자연사가 증가하였다. Real-time PCR 결과, 상피세포 표지유전자인 EVA, IL-7, AIRE, KGF는 TBT의 농도가 증가 할수록 발현량이 유의하게 감소한 반면, 지방세포 유도와 관련된 유전자인 PPARγ, aP2, PEPCK, CD36은 TBT의 농도가증가할수록 발현량이 유의하게 증가하였다. 세포자연사와 관련된 유전자인 TNFα, TNFR1도 TBT의 농도가 증가할수록발현량이 유의하게 증가하였다. 위의 결과를 종합하여볼 때, 내분비교란물질인 TBT는 흉선 상피세포에 직접적으로 작용하여 지방세포로 분화 유도시킴으로써 흉선의 기능을 상실케 만들면서 T 세포의 발달에 영향을 미치는 것으로 보인다. 이러한 결과는 지속적으로 노출되는 TBT가 흉선의 기능을 떨어뜨림으로써 면역력 저하를 유발시킬 수 있음을 제시하고있다.
Abstract
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. Therefore, in this study we examined how thymic function is reduced by TBT. To elucidate the mechanism, three-week-old SD female rats were orally administrated with TBT 1, 10, and 25 ㎎ per body weight (㎏) and sesame oil as a control for 7 days. On day 8, the thymi were obtained and weighed, and then the number of total thymocytes was counted. We also performed H&E staining,TUNEL assay, and flow cytometry of Annexin-V to examine the apoptosis rates and the structure in the thymus. Next,we investigated the adipogensis and apoptosis-related mRNA levels in the thymi by real-time PCR. The thymic weights and the number of thymocytes were decreased by TBT in a dose-depend 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 flow cytometry of Annexin-V, apoptosis 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 PPARγ, aP2, PEPCK, and CD36 were significantly increased. The expression of TNFα and TNFR1 as apoptotosis-related genes was significantly increased after TBT treatment. The present study demonstrated 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.
참고문헌 (47)
- Berger J, "The mechanisms of action of PPARs", Annu Rev Med, 53, pp.409~435 (2002)
- Blaber SJM, "The occurrence of a penis-like outgrowth behind the right tentacle in spent females of Nucella lapillus", J Mollus Stud, 39, pp.231~233 (1970)
- Carfi M, "TBTC induces adipocyte differentiation in human bone marrow long term culture", Toxicology, 249, pp.11~18 (2008)
- Chen Y, "Reduction of spermatogenesis in mice after tributyltin administration", Toxicology, 251, pp.21~27 (2008)
- Danilenko DM, "Preclinical and early clinical development of keratinocyte growth factor, an epithelialspecific tissue growth factor", Toxicol Pathol, 27, pp.64~71 (1999)
- Erickson M, "Regulation of thymic epithelium by keratinocyte growth factor", Blood, 100, pp.3269~3278 (2002)
- Fawthrop DJ, "Mechanisms of cell death", Arch Toxicol, 65, pp.437~444 (1991)
- Febbraio M, "CD36: a class B scavenger receptor involved in angiogenesis, atherosclerosis, inflammation, and lipid metabolism", J Clin Invest, 108, pp.785~791 (2001)
- Feng J, "Induction of CD36 expression by oxidized LDL and IL-4 by a common signaling pathway dependent on protein kinase C and PPAR-gamma", J Lipid Res, 41, pp.688~696 (2000)
- Gaur U, "Regulation of proliferation, survival and apoptosis by members of the TNF superfamily", Biochem Pharmacol, 66, pp.1403~1408 (2003)
- Gregoire FM, "Understanding adipocyte differentiation", Physiol Rev, 78, pp.783~809 (1998)
- Grü F, "Endocrine-disrupting organotin compounds are potent inducers of adipogenesis in vertebrates", Mol Endocrinol, 20, pp.2141~2155 (2006)
- Grundler W, "Early functional apoptotic responses of thymocytes induced by Tri-n-butyltin", Cytometry, 44, pp.45~56 (2001)
- Hare KJ, "An essential role for the IL-7 receptor during intrathymic expansion of the positively selected neonatal T cell repertoire", J Immunol, 165, pp.2410~2414 (2000)
- Ibrahimi A, "Expression of the CD36 homolog (FAT) in fibroblast cells: effects on fatty acid transport", Proc Natl Acad Sci USA, 93, pp.2646~2651 (1996)
- Kanayama T, "Organotin compounds promote adipocyte differentiation as agonists of the peroxisome proliferator-activated receptor gamma", retinoid X receptor pathway, 2005, pp.67, 766~774
- Ken Nakano, "Tributyltin (TBT) increases TNFα mRNA expression and induces apoptosis in the murine macrophage cell line in vitro", Environ Health Prev Med, 9, pp.266~271 (2004)
- Kim SK, "Inhibitory effect of tributyltin on expression of steroidogenic enzymes in mouse testis", INT J TOXICOL, 27, pp.175~182 (2008), TAYLOR & FRANCIS INC
- Kirchner S, "Prenatal exposure to the environmental obesogen tributyltin predisposes multipotent stem cells to become adipocytes", Mol Endocrinol, 24, pp.526~539 (2010)
- Le Maire A, "Activation of RXR-PPAR heterodimers by organotin environmental endocrine disruptors", EMBO Rep, 10, pp.367~373 (2009)
- Li X, "The environmental obesogen tributyltin chloride acts via peroxisome proliferator activated receptor gamma to induce adipogenesis in murine 3T3-L1 preadipocytes", J Steroid Biochem Mol Biol, 127, pp.9~15 (2011)
- Linton PJ, "Age-related changes in lymphocyte development and function", Nat Immunol, 5, pp.133~139 (2004)
- Liston A, "Aire regulates negative selection of organ-specific T cells", Nat Immunol, 4, pp.350~354 (2003)
- Liu Y, "Mesenchymal stem cell-based tissue regeneration is governed by recipient T lymphocytes via IFN-γ and TNF-α", Nat Med, 17, pp.1594~1601 (2011)
- Love PE, "Signal integration and crosstalk during thymocyte migration and emigration", Nat Rev Immunol, 11, pp.469~477 (2011)
- Lynch HE, "Thymic involution and immune reconstitution", Trends Immunol, 30, pp.366~373 (2009)
- Mandrup S, "Regulating adipogenesis", J Biol Chem, 272, pp.5367~5370 (1997)
- Maraskovsky E, "Bcl-2 can rescue T lymphocyte development in interleukin-7 receptor-deficient mice but not in mutant rag-1-", - mice, 1997, pp.89, 1101~1109
- Maria G, "Epithelial V-like antigen (EVA), a Novel Member of the immunoglobulin Superfamily, Expressed in embryonic epithelia with a potential role as homotypic adhesion molecule in thymus histogenesis", J Cell Biol, 141, pp.1061~1071 (1998)
- Michalik L, "International Union of Pharmacology. LXI. Peroxisome proliferator- activated receptors", Pharmacol Rev, 58, pp.726~741 (2006)
- Micheau O, "Induction of TNF receptor I-mediated apoptosis via two sequential signaling complexes", Cell, 114, pp.181~190 (2003)
- Middlebrook AJ, "TNF-alpha mediated modulation of T cell development and exacerbation of in vitro T1DM in fetal thymus organ culture", J Autoimmun, 29, pp.134~145 (2007)
- Murray J, "Regulation of neutrophil apoptosis by tumor necrosis factor-alpha: requirement for TNFR55 and TNFR75 for induction of apoptosis in vitro", Blood, 90, pp.2772~2783 (1997)
- Nakanishi T, "Endocrine disruption induced by organotin compounds; organotins function as a powerful agonist for nuclear receptors rather than an aromatase inhibitor", J Toxicol Sci, 33, pp.269~276 (2008)
- Raffray M, "Thymocyte apoptosis as a mechanism for tributyltin-induced thymic atrophy in vivo", Arch Toxicol, 67, pp.231~236 (1993)
- Shao D, "Peroxisome proliferator activated receptorγ, CCAAT", enhancer-binding protein α, and cell cycle status regulate the commitment to adipocyte differentiation, 1997, pp.272, 21473~21478
- Shawky S, "Distribution pattern of organotin compounds at different trophic levels of aquatic ecosystems", Chemosphere, 36, pp.523~535 (1998)
- Smialowicz RJ, "Immunotoxicity of tributyltin oxide in rats exposed as adults or pre-weanlings", Toxicology, 57, pp.97~111 (1989)
- Snoeij NJ, "Dibutyltin and tributyltin compounds induce thymus atrophy in rats due to a selective action on thymic lyphoblasts", Int J Immunopharmacol, 10, pp.891~899 (1988)
- Song YH, "Tributyltin increase adipogenesis and apoptosis of rat testicular interstitial cells", Dev Reprod, 4, pp.297~306 (2010)
- Taub DD, "Insights into thymic aging and regeneration", Immunol Rev, 205, pp.72~93 (2005)
- Tomiyama K, "Analysis of mechanisms of cell death of Tlymphocytes induced by organotin agents", J Immunotoxicol, 6, pp.184~193 (2009)
- Trigueros C, "Pre-TCR signaling regulates IL-7 receptor alphaexpression promoting thymocyte survival at the transition from the doublenegative to double-positive stage", Eur J Immunol, 33, pp.1968~1977 (2003)
- Ueno S, "Reduction in peripheral lymphocytes and thymus atrophy induced by organotin compounds in vivo", J Vet Med Sci, 71, pp.1041~1048 (2009)
- Yang H, "Inhibition of thymic adipogenesis by caloric restriction is coupled with reduction in age-related thymic involution", J Immunol, 183, pp.3040~3052 (2009)
- Youm YH, "Thiazolidinedione treatment and constitutive- PPARgamma activation induces ectopic adipogenesis and promotes age-related thymic involution", Aging Cell, 9, pp.478~489 (2010)
- Zucker RM, "Tributyltin and dexamethasone induce apoptosis in rat thymocytes by mutually antagonistic mechanisms", Toxicol Appl Pharmacol, 127, pp.163~170 (1994)