title: TLR4 is constitutively expressed in chick thymic epithelial cells.
abstract: Toll-like receptor 4 (TLR4) has been suggested to play a regulatory role in immune cell development; however, studies regarding the role of TLR4 in the development of the chick thymus are scarce. In this study, we investigated the distribution and expression pattern of TLR4 in normal chick thymi at different stages of development, in order to better understand the role of TLR4 in chick thymus development. We studied the thymi from 15 chicks, collected at days 7, 21 and 35 of age. The relative change in TLR4 mRNA expression in the chick thymus at different ages was determined by quantitative real-time PCR, and changes in protein expression were analyzed by immunohistochemistry and Western blotting. Furthermore, the distribution of TLR4 in the chick thymus was analyzed by immunohistochemistry, and compared with the distribution of TLR4 expression in juvenile female pigs (gilts). Our results indicated that TLR4 was constitutively expressed in the chick thymus. TLR4 was primarily expressed in the thymic cortico-medullary junction and the medulla, particularly in the epithelial cells of Hassall's corpuscles. The mRNA and protein expression level of TLR4 increased in the thymus with increasing age (p<0.05). Taken together, these results indicate that TLR4 is constitutively expressed by epithelial cells in the chick thymus, suggesting it may participate in thymic development by inducing factors affecting its development.
authors: Department of Anatomy, Histology and Embryology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China.
authors: Hai-Bo
authors: HB
authors: Huang
authors: Department of Anatomy, Histology and Embryology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China.
authors: Quan-Hang
authors: QH
authors: Xiang
authors: Department of Anatomy, Histology and Embryology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China.
authors: Hui
authors: H
authors: Wu
authors: Department of Anatomy, Histology and Embryology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China.
authors: Abdur Rahman
authors: AR
authors: Ansari
authors: Department of Anatomy, Histology and Embryology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China.
authors: Le
authors: L
authors: Wen
authors: Department of Anatomy, Histology and Embryology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China.
authors: Xiao-Hong
authors: XH
authors: Ge
authors: Department of Anatomy, Histology and Embryology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China.
authors: Ji-Xiang
authors: JX
authors: Wang
authors: Department of Anatomy, Histology and Embryology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China.
authors: Ke-Mei
authors: KM
authors: Peng
authors: Department of Anatomy, Histology and Embryology, College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China. Electronic address: lhz219@mail.hzau.edu.cn.
authors: Hua-Zhen
authors: HZ
authors: Liu
mesh_terms: D000818:Animals; D030161:Avian Proteins / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*; D004847:Epithelial Cells / Q000276:immunology / Q000378:metabolism; D005260:Female; D018507:Gene Expression Regulation, Developmental; D007150:Immunohistochemistry; D007633:Keratins / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D013045:Species Specificity; D034421:Sus scrofa / Q000235:genetics / Q000276:immunology; D013950:Thymus Gland / Q000166:cytology / Q000254:growth & development* / Q000276:immunology*; D051197:Toll-Like Receptor 4 / Q000235:genetics / Q000378:metabolism*
chemical_list: D030161:Avian Proteins; D012333:RNA, Messenger; D051197:Toll-Like Receptor 4; D007633:Keratins
keywords: Chick; Thymus development; Toll-like receptor 4