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Fasting enhances TRAIL-mediated liver natural killer cell activity via HSP70 upregulation.

Dang VT, Tanabe K, Tanaka Y, Tokumoto N, Misumi T, Saeki Y, Fujikuni N, Ohdan H - PLoS ONE (2014)

Bottom Line: Liver natural killer cells also showed high TRAIL-mediated antitumor function in response to 3-day fasting.Treatment of liver lymphocytes with 50 µg/mL of recombinant heat shock protein 70 led to the upregulation of both TRAIL and CD69 in liver natural killer cells (n = 6, p <0.05).These findings indicate that acute fasting enhances TRAIL-mediated liver natural killer cell activity against neoplastic cells through upregulation of heat shock protein 70.

View Article: PubMed Central - PubMed

Affiliation: Department of Gastroenterological and Transplant Surgery, Applied Life Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.

ABSTRACT
Acute starvation, which is frequently observed in clinical practice, sometimes augments the cytolytic activity of natural killer cells against neoplastic cells. In this study, we investigated the molecular mechanisms underlying the enhancement of natural killer cell function by fasting in mice. The total number of liver resident natural killer cells in a unit weight of liver tissue obtained from C57BL/6J mice did not change after a 3-day fast, while the proportions of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)+ and CD69+ natural killer cells were significantly elevated (n = 7, p <0.01), as determined by flow cytometric analysis. Furthermore, we found that TRAIL- natural killer cells that were adoptively transferred into Rag-2-/- γ chain-/- mice could convert into TRAIL+ natural killer cells in fasted mice at a higher proportion than in fed mice. Liver natural killer cells also showed high TRAIL-mediated antitumor function in response to 3-day fasting. Since these fasted mice highly expressed heat shock protein 70 (n = 7, p <0.05) in liver tissues, as determined by western blot, the role of this protein in natural killer cell activation was investigated. Treatment of liver lymphocytes with 50 µg/mL of recombinant heat shock protein 70 led to the upregulation of both TRAIL and CD69 in liver natural killer cells (n = 6, p <0.05). In addition, HSP70 neutralization by intraperitoneally injecting an anti- heat shock protein 70 monoclonal antibody into mice prior to fasting led to the downregulation of TRAIL expression (n = 6, p <0.05). These findings indicate that acute fasting enhances TRAIL-mediated liver natural killer cell activity against neoplastic cells through upregulation of heat shock protein 70.

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Neutralization effect of an anti-heat shock protein 70 monoclonal antibody on the natural killer cell phenotype.Mice received intraperitoneal injections of an anti-heat shock protein (HSP) 70 monoclonal antibody or isotype-matched mouse immunoglobulin G (6 mice per group) just before fasting. After a 3-day fast, liver lymphocytes were harvested for phenotyping by flow cytometry. (A) The distribution of TRAIL and CD69 expression on electronically gated TCRβ− NK1.1+ natural killer (NK) cells is indicated with solid lines (shaded areas). The percentage and mean fluorescence intensity (MFI) of TRAIL+ or CD69+ NK cells are provided. The dotted lines represent the distribution in the negative control. (B) TCRβ− NK1.1+, (C) TRAIL+ and CD69+ NK cell proportions, and (D) MFI from NK cells positive for those markers are shown in bar graphs as mean plus standard deviation (n = 6). The difference among the groups was analyzed using the independent samples T test; *p <0.05.
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pone-0110748-g008: Neutralization effect of an anti-heat shock protein 70 monoclonal antibody on the natural killer cell phenotype.Mice received intraperitoneal injections of an anti-heat shock protein (HSP) 70 monoclonal antibody or isotype-matched mouse immunoglobulin G (6 mice per group) just before fasting. After a 3-day fast, liver lymphocytes were harvested for phenotyping by flow cytometry. (A) The distribution of TRAIL and CD69 expression on electronically gated TCRβ− NK1.1+ natural killer (NK) cells is indicated with solid lines (shaded areas). The percentage and mean fluorescence intensity (MFI) of TRAIL+ or CD69+ NK cells are provided. The dotted lines represent the distribution in the negative control. (B) TCRβ− NK1.1+, (C) TRAIL+ and CD69+ NK cell proportions, and (D) MFI from NK cells positive for those markers are shown in bar graphs as mean plus standard deviation (n = 6). The difference among the groups was analyzed using the independent samples T test; *p <0.05.

Mentions: To further clarify the relationship between HSP70 and TRAIL-mediated NK cell function, an in vivo HSP70 neutralization assay was performed. Either an anti-HSP70 mAb or a mouse IgG isotype-matched control antibody was intraperitoneally injected (100 µg per mouse) into mice on day 0 before fasting. After the mice had been fasted for 3 days, their liver lymphocytes were harvested for NK cell phenotypic determination. The two groups of mice did not differ in terms of their body weight or liver lymphocyte yield (data not shown). TRAIL and CD69 expression in the TCRβ− NK1.1+ NK cells was then assessed by flow cytometry (Figure 8A). Although there was no difference in NK cell frequency between the two groups (Figure 8B), TRAIL expression in liver NK cells from mice injected with the anti-HSP70 mAb was significantly lower than that in cells from the control group (Figure 8C). CD69 expression was also downregulated in cells from mice injected with the anti-HSP70 mAb, but no significance was observed (p = 0.07; Figure 8C). MFI of TRAIL or CD69 positive NK cells did not significantly differ between two groups of mice (Figure 8D).


Fasting enhances TRAIL-mediated liver natural killer cell activity via HSP70 upregulation.

Dang VT, Tanabe K, Tanaka Y, Tokumoto N, Misumi T, Saeki Y, Fujikuni N, Ohdan H - PLoS ONE (2014)

Neutralization effect of an anti-heat shock protein 70 monoclonal antibody on the natural killer cell phenotype.Mice received intraperitoneal injections of an anti-heat shock protein (HSP) 70 monoclonal antibody or isotype-matched mouse immunoglobulin G (6 mice per group) just before fasting. After a 3-day fast, liver lymphocytes were harvested for phenotyping by flow cytometry. (A) The distribution of TRAIL and CD69 expression on electronically gated TCRβ− NK1.1+ natural killer (NK) cells is indicated with solid lines (shaded areas). The percentage and mean fluorescence intensity (MFI) of TRAIL+ or CD69+ NK cells are provided. The dotted lines represent the distribution in the negative control. (B) TCRβ− NK1.1+, (C) TRAIL+ and CD69+ NK cell proportions, and (D) MFI from NK cells positive for those markers are shown in bar graphs as mean plus standard deviation (n = 6). The difference among the groups was analyzed using the independent samples T test; *p <0.05.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4214715&req=5

pone-0110748-g008: Neutralization effect of an anti-heat shock protein 70 monoclonal antibody on the natural killer cell phenotype.Mice received intraperitoneal injections of an anti-heat shock protein (HSP) 70 monoclonal antibody or isotype-matched mouse immunoglobulin G (6 mice per group) just before fasting. After a 3-day fast, liver lymphocytes were harvested for phenotyping by flow cytometry. (A) The distribution of TRAIL and CD69 expression on electronically gated TCRβ− NK1.1+ natural killer (NK) cells is indicated with solid lines (shaded areas). The percentage and mean fluorescence intensity (MFI) of TRAIL+ or CD69+ NK cells are provided. The dotted lines represent the distribution in the negative control. (B) TCRβ− NK1.1+, (C) TRAIL+ and CD69+ NK cell proportions, and (D) MFI from NK cells positive for those markers are shown in bar graphs as mean plus standard deviation (n = 6). The difference among the groups was analyzed using the independent samples T test; *p <0.05.
Mentions: To further clarify the relationship between HSP70 and TRAIL-mediated NK cell function, an in vivo HSP70 neutralization assay was performed. Either an anti-HSP70 mAb or a mouse IgG isotype-matched control antibody was intraperitoneally injected (100 µg per mouse) into mice on day 0 before fasting. After the mice had been fasted for 3 days, their liver lymphocytes were harvested for NK cell phenotypic determination. The two groups of mice did not differ in terms of their body weight or liver lymphocyte yield (data not shown). TRAIL and CD69 expression in the TCRβ− NK1.1+ NK cells was then assessed by flow cytometry (Figure 8A). Although there was no difference in NK cell frequency between the two groups (Figure 8B), TRAIL expression in liver NK cells from mice injected with the anti-HSP70 mAb was significantly lower than that in cells from the control group (Figure 8C). CD69 expression was also downregulated in cells from mice injected with the anti-HSP70 mAb, but no significance was observed (p = 0.07; Figure 8C). MFI of TRAIL or CD69 positive NK cells did not significantly differ between two groups of mice (Figure 8D).

Bottom Line: Liver natural killer cells also showed high TRAIL-mediated antitumor function in response to 3-day fasting.Treatment of liver lymphocytes with 50 µg/mL of recombinant heat shock protein 70 led to the upregulation of both TRAIL and CD69 in liver natural killer cells (n = 6, p <0.05).These findings indicate that acute fasting enhances TRAIL-mediated liver natural killer cell activity against neoplastic cells through upregulation of heat shock protein 70.

View Article: PubMed Central - PubMed

Affiliation: Department of Gastroenterological and Transplant Surgery, Applied Life Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.

ABSTRACT
Acute starvation, which is frequently observed in clinical practice, sometimes augments the cytolytic activity of natural killer cells against neoplastic cells. In this study, we investigated the molecular mechanisms underlying the enhancement of natural killer cell function by fasting in mice. The total number of liver resident natural killer cells in a unit weight of liver tissue obtained from C57BL/6J mice did not change after a 3-day fast, while the proportions of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)+ and CD69+ natural killer cells were significantly elevated (n = 7, p <0.01), as determined by flow cytometric analysis. Furthermore, we found that TRAIL- natural killer cells that were adoptively transferred into Rag-2-/- γ chain-/- mice could convert into TRAIL+ natural killer cells in fasted mice at a higher proportion than in fed mice. Liver natural killer cells also showed high TRAIL-mediated antitumor function in response to 3-day fasting. Since these fasted mice highly expressed heat shock protein 70 (n = 7, p <0.05) in liver tissues, as determined by western blot, the role of this protein in natural killer cell activation was investigated. Treatment of liver lymphocytes with 50 µg/mL of recombinant heat shock protein 70 led to the upregulation of both TRAIL and CD69 in liver natural killer cells (n = 6, p <0.05). In addition, HSP70 neutralization by intraperitoneally injecting an anti- heat shock protein 70 monoclonal antibody into mice prior to fasting led to the downregulation of TRAIL expression (n = 6, p <0.05). These findings indicate that acute fasting enhances TRAIL-mediated liver natural killer cell activity against neoplastic cells through upregulation of heat shock protein 70.

Show MeSH
Related in: MedlinePlus