Naomi Terada1, Mohammad Rabiul Karim1, Takeshi Izawa1, Mitsuru Kuwamura1, Jyoji Yamate2. 1. Laboratory of Veterinary Pathology, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-58 Rinku-Ourai-Kita, Izumisano City, Osaka, 598-8531, Japan. 2. Laboratory of Veterinary Pathology, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-58 Rinku-Ourai-Kita, Izumisano City, Osaka, 598-8531, Japan. yamate@vet.osakafu-u.ac.jp.
Abstract
BACKGROUND: β-Catenin is a multi-functional protein involved in nephrogenesis and also plays important roles in renal injury. Here, the expression of β-catenin was investigated in the proximal renal tubular epithelial cells in cisplatin (CDDP)-induced acute kidney injury (AKI) and chronic kidney injury (CKI), because CDDP-induced renal lesions were characterized by proximal renal tubular epithelial degeneration/regeneration and subsequent interstitial fibrosis. METHODS: F344 rats were treated with CDDP. The expression of β-catenin and proliferative (Ki67) or fibrogenic [vimentin, α-smooth action (α-SMA)] markers was analyzed by immunolabeling. RESULTS: β-Catenin, vimentin and Ki67 were not seen in the proximal renal tubules of control rats. Interestingly, in CDDP-induced AKI, the regenerating proximal renal tubular epithelial cells reacting strongly with Ki67 expressed membranous or cytoplasmic β-catenin and also showed a positive reaction to vimentin but not to α-SMA. In CDDP-induced CKI, the epithelial cells of abnormally dilated or atrophied renal tubules did not react to β-catenin or Ki67, but showed positive reactions to vimentin and α-SMA. β-Catenin mRNAs were significantly increased in AKI and significantly decreased in CKI. CONCLUSION: Newly expressed β-catenin in the proximal renal tubules after AKI may participate in functional regeneration. In CKI, epithelial cells of abnormal renal tubules did not express β-catenin but reacted to vimentin, and α-SMA might indicate the epithelial-mesenchymal transition (EMT) formation, because α-SMA is usually expressed in myofibroblasts forming via EMT. The presence or absence of β-catenin expression would become a marker for the EMT phenomenon in progressive renal fibrosis.
BACKGROUND: β-Catenin is a multi-functional protein involved in nephrogenesis and also plays important roles in renal injury. Here, the expression of β-catenin was investigated in the proximal renal tubular epithelial cells in cisplatin (CDDP)-induced acute kidney injury (AKI) and chronic kidney injury (CKI), because CDDP-induced renal lesions were characterized by proximal renal tubular epithelial degeneration/regeneration and subsequent interstitial fibrosis. METHODS: F344 rats were treated with CDDP. The expression of β-catenin and proliferative (Ki67) or fibrogenic [vimentin, α-smooth action (α-SMA)] markers was analyzed by immunolabeling. RESULTS: β-Catenin, vimentin and Ki67 were not seen in the proximal renal tubules of control rats. Interestingly, in CDDP-induced AKI, the regenerating proximal renal tubular epithelial cells reacting strongly with Ki67 expressed membranous or cytoplasmic β-catenin and also showed a positive reaction to vimentin but not to α-SMA. In CDDP-induced CKI, the epithelial cells of abnormally dilated or atrophied renal tubules did not react to β-catenin or Ki67, but showed positive reactions to vimentin and α-SMA. β-Catenin mRNAs were significantly increased in AKI and significantly decreased in CKI. CONCLUSION: Newly expressed β-catenin in the proximal renal tubules after AKI may participate in functional regeneration. In CKI, epithelial cells of abnormal renal tubules did not express β-catenin but reacted to vimentin, and α-SMA might indicate the epithelial-mesenchymal transition (EMT) formation, because α-SMA is usually expressed in myofibroblasts forming via EMT. The presence or absence of β-catenin expression would become a marker for the EMT phenomenon in progressive renal fibrosis.
Authors: J Yamate; A Okado; M Kuwamura; Y Tsukamoto; F Ohashi; Y Kiso; S Nakatsuji; T Kotani; S Sakuma; J Lamarre Journal: Toxicol Pathol Date: 1998 Nov-Dec Impact factor: 1.902