Ochratoxin A (OTA) is one of the most frequently occurring mycotoxins in several food products and, under experimental conditions, it causes a wide spectrum of toxic effects, including teratogenicity, carcinogenicity, nephrotoxicity, and immunotoxicity. In laboratory animals, the exposure to OTA during pregnancy may interfere with embryonic development and may induce embryo lethality, growth delay and teratogenic effects. An alternative approach to in vitro predict the developmental risk of chemicals has been offered by mesenchymal stem cells (MSCs) isolated from fetal adnexa. The aim of this work is to study OTA effects at nanomolar concentrations, corresponding to levels detected in human placenta, on proliferation of canine umbilical cord matrix MSCs (UCM-MSCs). Cells were plated in 12-well dishes to perform doubling time (DT) analysis, cellular density and viability from passage (P) 1 to P7, by using Trypan blue dye exclusion test. OTA was added at concentrations ranging from 0.01ng/ml to 10ng/ml. Two experimental protocols of OTA treatment were performed: 1) continue exposure model; 2) alternate exposure model, in which cultures were performed for 3 days in standard medium followed by 4 days in presence of OTA. Control cultures received the same amount of OTA solvent (DMSO). After OTA exposure, cell proliferation was observed until P3, in contrast to control samples in which cells proliferated until P7. In both exposure models, DT values were higher than those found in control samples. In particular, lowest OTA concentrations (0.01–0.1ng/ml) significantly increased (P<0.0001) DT values compared with controls in both exposure models, with consequent inhibition of cell proliferation. No differences were observed between continue and alternate exposure models, leading to suppose that the cell damage early occurs and cannot be reversed independently of exposure model. At all passages, OTA treatment did not influence cell viability. In addition, changes in osteo- and neuron-like morphology were observed in treated cells at P3, in contrast with controls that maintained fibroblast-like morphology. The action mechanism of OTA on cell proliferation, at nanomolar concentrations, is not clear. It has been reported in renal epithelial cells that OTA may interact with cellular key targets, such as mitochondria, and interfere with Ca2+, pH and energy homeostasis, leading to the disturbance of cell signaling/proliferation and apoptosis. Moreover, OTA, in renal epithelial cells, may activate MAP-kinase, which cause cell dedifferentiation and transformation: this evidence could explain the morphological changes observed also in UCM-MSCs. In conclusion, OTA, at nanomolar concentrations, modulates physiological signals influencing cell growth, self-renewal and differentiation in UCM-MSCs as it may occur during embryo development.

Toxic effect induced by ochratoxin A on fetal mesenchymal stem cells at nanomolar levels

VALENTINI, Luisa
2013-01-01

Abstract

Ochratoxin A (OTA) is one of the most frequently occurring mycotoxins in several food products and, under experimental conditions, it causes a wide spectrum of toxic effects, including teratogenicity, carcinogenicity, nephrotoxicity, and immunotoxicity. In laboratory animals, the exposure to OTA during pregnancy may interfere with embryonic development and may induce embryo lethality, growth delay and teratogenic effects. An alternative approach to in vitro predict the developmental risk of chemicals has been offered by mesenchymal stem cells (MSCs) isolated from fetal adnexa. The aim of this work is to study OTA effects at nanomolar concentrations, corresponding to levels detected in human placenta, on proliferation of canine umbilical cord matrix MSCs (UCM-MSCs). Cells were plated in 12-well dishes to perform doubling time (DT) analysis, cellular density and viability from passage (P) 1 to P7, by using Trypan blue dye exclusion test. OTA was added at concentrations ranging from 0.01ng/ml to 10ng/ml. Two experimental protocols of OTA treatment were performed: 1) continue exposure model; 2) alternate exposure model, in which cultures were performed for 3 days in standard medium followed by 4 days in presence of OTA. Control cultures received the same amount of OTA solvent (DMSO). After OTA exposure, cell proliferation was observed until P3, in contrast to control samples in which cells proliferated until P7. In both exposure models, DT values were higher than those found in control samples. In particular, lowest OTA concentrations (0.01–0.1ng/ml) significantly increased (P<0.0001) DT values compared with controls in both exposure models, with consequent inhibition of cell proliferation. No differences were observed between continue and alternate exposure models, leading to suppose that the cell damage early occurs and cannot be reversed independently of exposure model. At all passages, OTA treatment did not influence cell viability. In addition, changes in osteo- and neuron-like morphology were observed in treated cells at P3, in contrast with controls that maintained fibroblast-like morphology. The action mechanism of OTA on cell proliferation, at nanomolar concentrations, is not clear. It has been reported in renal epithelial cells that OTA may interact with cellular key targets, such as mitochondria, and interfere with Ca2+, pH and energy homeostasis, leading to the disturbance of cell signaling/proliferation and apoptosis. Moreover, OTA, in renal epithelial cells, may activate MAP-kinase, which cause cell dedifferentiation and transformation: this evidence could explain the morphological changes observed also in UCM-MSCs. In conclusion, OTA, at nanomolar concentrations, modulates physiological signals influencing cell growth, self-renewal and differentiation in UCM-MSCs as it may occur during embryo development.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11586/90491
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