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The Orphan Nuclear Receptor NR4A1 Protects Pancreatic β-Cells from Endoplasmic Reticulum (ER) Stress-mediated Apoptosis.

Yu C, Cui S, Zong C, Gao W, Xu T, Gao P, Chen J, Qin D, Guan Q, Liu Y, Fu Y, Li X, Wang X - J. Biol. Chem. (2015)

Bottom Line: This conclusion was further confirmed by experiments exploiting siRNA to knockdown NR4A1 expression in MIN6 cells or exploiting NR4A1 knock-out mice.NR4A1 overexpression in MIN6 cells or mouse islets resulted in Survivin up-regulation.In conclusion, NR4A1 protects pancreatic β-cells against ER stress-mediated apoptosis by up-regulating Survivin expression and down-regulating CHOP expression, which we termed as "positive and negative regulation."

View Article: PubMed Central - PubMed

Affiliation: From the The Department of Cell Biology, Shandong University School of Medicine, Jinan, China, 250012.

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The effect of NR4A1 on Caspase3 activation upon TG or PA treatment.A and B, NR4A1 and active Caspase3 (17 kDa) protein levels in NC and OV cells in response to 0.5 μm TG (A) or 0.4 mm PA (B) at a series of time points. C and D, NR4A1, CHOP, and active Caspase3 (17 kDa) protein levels in response to 0.5 μm TG (C) or 0.4 mm PA (D) at a series of time points in MIN6 cell transient overexpression of NR4A1 or GFP only by adenoviral infection. Densitometric analyses of the Western blots are shown as curves. The data show the means of three independent experiments. *, p < 0.05; **, p < 0.01; ***, p < 0.001 versus NC.
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Figure 4: The effect of NR4A1 on Caspase3 activation upon TG or PA treatment.A and B, NR4A1 and active Caspase3 (17 kDa) protein levels in NC and OV cells in response to 0.5 μm TG (A) or 0.4 mm PA (B) at a series of time points. C and D, NR4A1, CHOP, and active Caspase3 (17 kDa) protein levels in response to 0.5 μm TG (C) or 0.4 mm PA (D) at a series of time points in MIN6 cell transient overexpression of NR4A1 or GFP only by adenoviral infection. Densitometric analyses of the Western blots are shown as curves. The data show the means of three independent experiments. *, p < 0.05; **, p < 0.01; ***, p < 0.001 versus NC.

Mentions: Caspase3 activation is the canonical biological marker for apoptosis, and full-length Caspase3 is cleaved into a 17-kDa fragment during apoptosis. Therefore, we examined the levels of cleaved Caspase3 using Western blotting. We treated both NC and OV cells with TG or PA for various lengths of time, and Western blotting results revealed that OV cells had lower Caspase3 (17 kDa) levels compared with NC cells upon treatment with TG (Fig. 4A) or PA (Fig. 4B). Furthermore, Caspase3 (17 kDa) levels peaked later after TG treatment in OV cells than in NC cells. Moreover, transient overexpression NR4A1 with adenoviral infection in MIN6 cells resulted in reduced CHOP expression and decreased Caspase3 activation upon TG or PA treatment compared with control MIN6 cells infected with control adenovirus (Fig. 4, C and D).


The Orphan Nuclear Receptor NR4A1 Protects Pancreatic β-Cells from Endoplasmic Reticulum (ER) Stress-mediated Apoptosis.

Yu C, Cui S, Zong C, Gao W, Xu T, Gao P, Chen J, Qin D, Guan Q, Liu Y, Fu Y, Li X, Wang X - J. Biol. Chem. (2015)

The effect of NR4A1 on Caspase3 activation upon TG or PA treatment.A and B, NR4A1 and active Caspase3 (17 kDa) protein levels in NC and OV cells in response to 0.5 μm TG (A) or 0.4 mm PA (B) at a series of time points. C and D, NR4A1, CHOP, and active Caspase3 (17 kDa) protein levels in response to 0.5 μm TG (C) or 0.4 mm PA (D) at a series of time points in MIN6 cell transient overexpression of NR4A1 or GFP only by adenoviral infection. Densitometric analyses of the Western blots are shown as curves. The data show the means of three independent experiments. *, p < 0.05; **, p < 0.01; ***, p < 0.001 versus NC.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4543630&req=5

Figure 4: The effect of NR4A1 on Caspase3 activation upon TG or PA treatment.A and B, NR4A1 and active Caspase3 (17 kDa) protein levels in NC and OV cells in response to 0.5 μm TG (A) or 0.4 mm PA (B) at a series of time points. C and D, NR4A1, CHOP, and active Caspase3 (17 kDa) protein levels in response to 0.5 μm TG (C) or 0.4 mm PA (D) at a series of time points in MIN6 cell transient overexpression of NR4A1 or GFP only by adenoviral infection. Densitometric analyses of the Western blots are shown as curves. The data show the means of three independent experiments. *, p < 0.05; **, p < 0.01; ***, p < 0.001 versus NC.
Mentions: Caspase3 activation is the canonical biological marker for apoptosis, and full-length Caspase3 is cleaved into a 17-kDa fragment during apoptosis. Therefore, we examined the levels of cleaved Caspase3 using Western blotting. We treated both NC and OV cells with TG or PA for various lengths of time, and Western blotting results revealed that OV cells had lower Caspase3 (17 kDa) levels compared with NC cells upon treatment with TG (Fig. 4A) or PA (Fig. 4B). Furthermore, Caspase3 (17 kDa) levels peaked later after TG treatment in OV cells than in NC cells. Moreover, transient overexpression NR4A1 with adenoviral infection in MIN6 cells resulted in reduced CHOP expression and decreased Caspase3 activation upon TG or PA treatment compared with control MIN6 cells infected with control adenovirus (Fig. 4, C and D).

Bottom Line: This conclusion was further confirmed by experiments exploiting siRNA to knockdown NR4A1 expression in MIN6 cells or exploiting NR4A1 knock-out mice.NR4A1 overexpression in MIN6 cells or mouse islets resulted in Survivin up-regulation.In conclusion, NR4A1 protects pancreatic β-cells against ER stress-mediated apoptosis by up-regulating Survivin expression and down-regulating CHOP expression, which we termed as "positive and negative regulation."

View Article: PubMed Central - PubMed

Affiliation: From the The Department of Cell Biology, Shandong University School of Medicine, Jinan, China, 250012.

Show MeSH
Related in: MedlinePlus