title: Overexpression of regucalcin suppresses cell response for tumor necrosis factor-alpha or transforming growth factor-beta1 in cloned normal rat kidney proximal tubular epithelial NRK52E cells.
abstract: The regulatory role of regucalcin on cell responses for tumor necrosis factor-alpha (TNF-alpha) or transforming growth factor-beta1 (TGF-beta1) was investigated using the cloned normal rat kidney proximal tubular epithelial NRK52E cells overexpressing regucalcin. NRK52E cells (wild type) and stable regucalcin (RC)/pCXN2-transfected cells (transfectant) were cultured for 72 h in a medium containing 5% bovine serum (BS) to obtain subconfluent monolayers. After culture, cells were further cultured for 24-72 h in medium without BS containing either vehicle, TNF-alpha (0.1 or 1.0 ng/ml of medium), or TGF-beta1 (1.0 or 5.0 ng/ml). Culture with TNF-alpha or TGF-beta1 caused a significant decrease in the number of wild-type cells. This decrease was significantly prevented in transfectants overexpressing regucalcin. Agarose gel electrophoresis showed the presence of low-molecular-weight deoxyribonucleic acid (DNA) fragments of adherent wild-type cells cultured with TNF-alpha (1.0 ng/ml) or TGF-beta1 (5.0 ng/ml). This DNA fragmentation was significantly suppressed in transfectants. TNF-alpha- or TGF-beta1-induced cell death was significantly prevented in culture with caspase-3 inhibitor (10(-8) M). Nitric oxide (NO) synthase activity in wild-type cells was significantly increased by addition of calcium chloride (10 microM) and calmodulin (5 microg/ml) into the enzyme reaction mixture. This increase was significantly suppressed in transfectants. Culture with TNF-alpha caused a significant increase in NO synthase activity in wild-type cells. The effect of TNF-alpha was not seen in transfectants. Culture with TGF-beta1 did not cause a significant increase in NO synthase activity in wild-type cells and transfectants. Culture with TNF-alpha or TGF-beta1 caused a remarkable increase in alpha-smooth muscle actin in wild-type cells. This increase was significantly prevented in transfectants. The expression of Smad 2 or NF-kappaB mRNAs was significantly increased in transfectants as compared with that of wild-type cells. Smad 3 or glyceroaldehyde-3-phosphate dehydrogenase (G3PDH) mRNA expression was not significantly changed in transfectants. NF-kappaB mRNA expression in wild-type cells was significantly increased with culture of TNF-alpha. Smad 2 mRNA expression was significantly enhanced in wild-type cells cultured with TGF-beta1. These effects of TNF-alpha or TGF-beta1 were not significantly enhanced in transfectants. This study demonstrates that overexpression of regucalcin has suppressive effects on cell responses which are mediated through intracellular signaling pathways of TNF-alpha or TGF-beta1 in kidney NRK52E cells.
authors.affiliation: Laboratory of Endocrinology and Molecular Metabolism, Graduate School of Nutritional Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan.
authors.forename: Taeko
authors.initials: T
authors.lastname: Nakagawa
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Yamaguchi
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D002135:Calcium-Binding Proteins / Q000494:pharmacology*; D002265:Carboxylic Ester Hydrolases; D053148:Caspase 3 / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured / Q000187:drug effects / Q000378:metabolism; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000494:pharmacology*; D007687:Kidney Tubules, Proximal / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D053773:Transforming Growth Factor beta1 / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D015854:Up-Regulation
chemical_list: D000199:Actins; D002135:Calcium-Binding Proteins; D002265:Carboxylic Ester Hydrolases; D053148:Caspase 3; D047908:Intracellular Signaling Peptides and Proteins; D019001:Nitric Oxide Synthase; D012333:RNA, Messenger; D053773:Transforming Growth Factor beta1; D014409:Tumor Necrosis Factor-alpha; C498862:Acta2 protein, rat; C513325:Rgn protein, rat