Limits...
Sulforaphane Protects the Liver against CdSe Quantum Dot-Induced Cytotoxicity.

Wang W, He Y, Yu G, Li B, Sexton DW, Wileman T, Roberts AA, Hamilton CJ, Liu R, Chao Y, Shan Y, Bao Y - PLoS ONE (2015)

Bottom Line: Wortmannin inhibition of SFN-induced autophagy significantly suppressed the protective effect of SFN on CdSe QD-induced cell death.CdSe QDs caused significant liver damage in mice, and this was decreased by SFN treatment.In conclusion, SFN attenuated the cytotoxicity of CdSe QDs in both human hepatocytes and in the mouse liver, and this protection was associated with the induction of Nrf2 pathway and autophagy.

View Article: PubMed Central - PubMed

Affiliation: Norwich Medical School, University of East Anglia, Norwich, Norfolk, United Kingdom.

ABSTRACT
The potential cytotoxicity of cadmium selenide (CdSe) quantum dots (QDs) presents a barrier to their use in biomedical imaging or as diagnostic and therapeutic agents. Sulforaphane (SFN) is a chemoprotective compound derived from cruciferous vegetables which can up-regulate antioxidant enzymes and induce apoptosis and autophagy. This study reports the effects of SFN on CdSe QD-induced cytotoxicity in immortalised human hepatocytes and in the livers of mice. CdSe QDs induced dose-dependent cell death in hepatocytes with an IC50 = 20.4 μM. Pre-treatment with SFN (5 μM) increased cell viability in response to CdSe QDs (20 μM) from 49.5 to 89.3%. SFN induced a pro-oxidant effect characterized by depletion of intracellular reduced glutathione during short term exposure (3-6 h), followed by up-regulation of antioxidant enzymes and glutathione levels at 24 h. SFN also caused Nrf2 translocation into the nucleus, up-regulation of antioxidant enzymes and autophagy. siRNA knockdown of Nrf2 suggests that the Nrf2 pathway plays a role in the protection against CdSe QD-induced cell death. Wortmannin inhibition of SFN-induced autophagy significantly suppressed the protective effect of SFN on CdSe QD-induced cell death. Moreover, the role of autophagy in SFN protection against CdSe QD-induced cell death was confirmed using mouse embryonic fibroblasts lacking ATG5. CdSe QDs caused significant liver damage in mice, and this was decreased by SFN treatment. In conclusion, SFN attenuated the cytotoxicity of CdSe QDs in both human hepatocytes and in the mouse liver, and this protection was associated with the induction of Nrf2 pathway and autophagy.

No MeSH data available.


Related in: MedlinePlus

Effect of knockdown TR-1, Keap1 and Nrf2 on cytotoxicity in HHL-5 cells exposed to CdSe QDs.TR-1, Keap1 or Nrf2 were knocked down, respectively. Allstars (AS) were used as a negative control. Cells were incubated with 5 μM SFN or DMSO (0.1%) control for 24 h then exposed to 20 μM CdSe QDs for 24 h. Cell viability was measured by MTT assay, and data shown as means ± SD (n = 6). Significant levels (*P<0.05; **P<0.01) in comparison with AllStars (AS) negative controls.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4581733&req=5

pone.0138771.g004: Effect of knockdown TR-1, Keap1 and Nrf2 on cytotoxicity in HHL-5 cells exposed to CdSe QDs.TR-1, Keap1 or Nrf2 were knocked down, respectively. Allstars (AS) were used as a negative control. Cells were incubated with 5 μM SFN or DMSO (0.1%) control for 24 h then exposed to 20 μM CdSe QDs for 24 h. Cell viability was measured by MTT assay, and data shown as means ± SD (n = 6). Significant levels (*P<0.05; **P<0.01) in comparison with AllStars (AS) negative controls.

Mentions: TR-1 is driven by the Keap1-Nrf2-ARE signalling pathway. CdSe QDs (20 μM) decreased HHL-5 cell viability to 25.4% without SFN pretreatment. siTR-1 was found to have no significant effect on cell viability. However, siNrf2 knockdown indicated that diminished Nrf2 signalling enhanced the cytotoxicity of CdSe QDs, i.e. cell viability decreased from 25.4 to 19.7% (P<0.05) (Fig 4). In contrast, siKeap1, which enhances the Nrf2 pathway (S2 Fig) increased the cell viability to 34%. Pre-treatment with SFN (5 μM, 24 h), increased the cell viability to 59.1%. siTR-1 decreased CdSe QD-induced cell death from 59.1 to 50.7% (P<0.05, Fig 4); whereas siQR-1 has no effect on CdSe QD-induced cell death in HHL-5 cells (data not shown). Moreover, when Nrf2 was knocked-down, viable cell numbers decreased to 32.7% (P<0.01) indicating a significant abrogation of the protection provided by SFN against CdSe QD-induced cell death. In contrast, siKeap1 resulted in more Nrf2 translocation into nucleus, and siKeap1 plus SFN resulted in an enhanced protection (cell viability was increased to 68.7%, Fig 4). Taken together, these results demonstrate that Keap1-Nrf2-ARE signalling pathway plays an important role in CdSe QD-induced cell death.


Sulforaphane Protects the Liver against CdSe Quantum Dot-Induced Cytotoxicity.

Wang W, He Y, Yu G, Li B, Sexton DW, Wileman T, Roberts AA, Hamilton CJ, Liu R, Chao Y, Shan Y, Bao Y - PLoS ONE (2015)

Effect of knockdown TR-1, Keap1 and Nrf2 on cytotoxicity in HHL-5 cells exposed to CdSe QDs.TR-1, Keap1 or Nrf2 were knocked down, respectively. Allstars (AS) were used as a negative control. Cells were incubated with 5 μM SFN or DMSO (0.1%) control for 24 h then exposed to 20 μM CdSe QDs for 24 h. Cell viability was measured by MTT assay, and data shown as means ± SD (n = 6). Significant levels (*P<0.05; **P<0.01) in comparison with AllStars (AS) negative controls.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4581733&req=5

pone.0138771.g004: Effect of knockdown TR-1, Keap1 and Nrf2 on cytotoxicity in HHL-5 cells exposed to CdSe QDs.TR-1, Keap1 or Nrf2 were knocked down, respectively. Allstars (AS) were used as a negative control. Cells were incubated with 5 μM SFN or DMSO (0.1%) control for 24 h then exposed to 20 μM CdSe QDs for 24 h. Cell viability was measured by MTT assay, and data shown as means ± SD (n = 6). Significant levels (*P<0.05; **P<0.01) in comparison with AllStars (AS) negative controls.
Mentions: TR-1 is driven by the Keap1-Nrf2-ARE signalling pathway. CdSe QDs (20 μM) decreased HHL-5 cell viability to 25.4% without SFN pretreatment. siTR-1 was found to have no significant effect on cell viability. However, siNrf2 knockdown indicated that diminished Nrf2 signalling enhanced the cytotoxicity of CdSe QDs, i.e. cell viability decreased from 25.4 to 19.7% (P<0.05) (Fig 4). In contrast, siKeap1, which enhances the Nrf2 pathway (S2 Fig) increased the cell viability to 34%. Pre-treatment with SFN (5 μM, 24 h), increased the cell viability to 59.1%. siTR-1 decreased CdSe QD-induced cell death from 59.1 to 50.7% (P<0.05, Fig 4); whereas siQR-1 has no effect on CdSe QD-induced cell death in HHL-5 cells (data not shown). Moreover, when Nrf2 was knocked-down, viable cell numbers decreased to 32.7% (P<0.01) indicating a significant abrogation of the protection provided by SFN against CdSe QD-induced cell death. In contrast, siKeap1 resulted in more Nrf2 translocation into nucleus, and siKeap1 plus SFN resulted in an enhanced protection (cell viability was increased to 68.7%, Fig 4). Taken together, these results demonstrate that Keap1-Nrf2-ARE signalling pathway plays an important role in CdSe QD-induced cell death.

Bottom Line: Wortmannin inhibition of SFN-induced autophagy significantly suppressed the protective effect of SFN on CdSe QD-induced cell death.CdSe QDs caused significant liver damage in mice, and this was decreased by SFN treatment.In conclusion, SFN attenuated the cytotoxicity of CdSe QDs in both human hepatocytes and in the mouse liver, and this protection was associated with the induction of Nrf2 pathway and autophagy.

View Article: PubMed Central - PubMed

Affiliation: Norwich Medical School, University of East Anglia, Norwich, Norfolk, United Kingdom.

ABSTRACT
The potential cytotoxicity of cadmium selenide (CdSe) quantum dots (QDs) presents a barrier to their use in biomedical imaging or as diagnostic and therapeutic agents. Sulforaphane (SFN) is a chemoprotective compound derived from cruciferous vegetables which can up-regulate antioxidant enzymes and induce apoptosis and autophagy. This study reports the effects of SFN on CdSe QD-induced cytotoxicity in immortalised human hepatocytes and in the livers of mice. CdSe QDs induced dose-dependent cell death in hepatocytes with an IC50 = 20.4 μM. Pre-treatment with SFN (5 μM) increased cell viability in response to CdSe QDs (20 μM) from 49.5 to 89.3%. SFN induced a pro-oxidant effect characterized by depletion of intracellular reduced glutathione during short term exposure (3-6 h), followed by up-regulation of antioxidant enzymes and glutathione levels at 24 h. SFN also caused Nrf2 translocation into the nucleus, up-regulation of antioxidant enzymes and autophagy. siRNA knockdown of Nrf2 suggests that the Nrf2 pathway plays a role in the protection against CdSe QD-induced cell death. Wortmannin inhibition of SFN-induced autophagy significantly suppressed the protective effect of SFN on CdSe QD-induced cell death. Moreover, the role of autophagy in SFN protection against CdSe QD-induced cell death was confirmed using mouse embryonic fibroblasts lacking ATG5. CdSe QDs caused significant liver damage in mice, and this was decreased by SFN treatment. In conclusion, SFN attenuated the cytotoxicity of CdSe QDs in both human hepatocytes and in the mouse liver, and this protection was associated with the induction of Nrf2 pathway and autophagy.

No MeSH data available.


Related in: MedlinePlus