Open AccessInvestigation of effect of tectorigenin (O-methylated isoflavone) on Ca2+signal transduction and cytotoxic responses in canine renal tubular cells
Author(s) -
HeHsiung Cheng,
Wei Liang,
Wei-Chuan Liao,
Chun-Chi Kuo,
Lyh-Jyh Hao,
Chiang-Ting Chou,
ChungRen Jan
Publication year - 2020
Publication title -
chinese journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.396
H-Index - 31
eISSN - 2666-0059
pISSN - 0304-4920
DOI - 10.4103/cjp.cjp_14_20
Subject(s) - thapsigargin , chemistry , cytosol , phospholipase c , viability assay , egta , endoplasmic reticulum , biophysics , biochemistry , microbiology and biotechnology , calcium , pharmacology , signal transduction , apoptosis , biology , enzyme , organic chemistry
Tectorigenin, a traditional Chinese medicine, is isolated from the flower of plants such as Pueraria thomsonii Benth. It is an O-methylated isoflavone, a type of flavonoid. Previous studies have shown that tectorigenin evoked various physiological responses in different models, but the effect of tectorigenin on cytosolic-free Ca 2+ levels ([Ca 2+ ] i ) and cytotoxicity in renal tubular cells is unknown. Our research explored if tectorigenin changed Ca 2+ signal transduction and viability in Madin-Darby Canine Kidney (MDCK) renal tubular cells. [Ca 2+ ] i in suspended cells were measured by applying the fluorescent Ca 2+ -sensitive probe fura-2. Viability was explored by using water-soluble tetrazolium-1 as a fluorescent dye. Tectorigenin at concentrations of 5-50 μM induced [Ca 2+ ] i rises. Ca 2+ removal reduced the signal by approximately 20%. Tectorigenin (50 μM) induced Mn 2+ influx suggesting of Ca 2+ entry. Tectorigenin-induced Ca 2+ entry was inhibited by 10% by three inhibitors of store-operated Ca 2+ channels, namely, nifedipine, econazole, and SKF96365. In Ca 2+ -free medium, treatment with the endoplasmic reticulum Ca 2+ pump inhibitor thapsigargin inhibited 83% of tectorigenin-evoked [Ca 2+ ] i rises. Conversely, treatment with tectorigenin abolished thapsigargin-evoked [Ca 2+ ] i rises. Inhibition of phospholipase C with U73122 inhibited 50% of tectorigenin-induced [Ca 2+ ] i rises. Tectorigenin at concentrations between 10 and 60 μM killed cells in a concentration-dependent fashion. Chelation of cytosolic Ca 2+ with 1,2-bis (2-aminophenoxy)ethane-N, N, N', N'-tetraacetic acid/acetoxy methyl did not reverse tectorigenin's cytotoxicity. Our data suggest that, in MDCK cells, tectorigenin evoked [Ca 2+ ] i rises and induced cell death that was not associated with [Ca 2+ ] i rises. Therefore, tectorigenin may be a Ca 2+ -independent cytotoxic agent for kidney cells.