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The Hypothermic Influence on CHOP and Ero1-α in an Endoplasmic Reticulum Stress Model of Cerebral Ischemia.

Poone GK, Hasseldam H, Munkholm N, Rasmussen RS, Grønberg NV, Johansen FF - Brain Sci (2015)

Bottom Line: As a result of ischemia, a significant increase in expression of CHOP and Ero1-α was observed after three, six and twelve hours of reperfusion following global ischemia.On the contrary, the gene expression of Ero1-α increased as a result of hypothermia and peaked at twelve hours (p < 0.0001).As hypothermia further induced up-regulation of Ero1-α, and since CHOP and Ero1-α showed differential regulation as a consequence of both disease (hypoxia) and treatment (hypothermia), we conclude that they are regulated independently.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Sciences and Biotech Research & Innovation Centre (BRIC), University of Copenhagen, 2200, Denmark. gagandipkb@hotmail.com.

ABSTRACT
Hypoxia induced endoplasmic reticulum stress causes accumulation of unfolded proteins in the endoplasmic reticulum and activates the unfolded protein response, resulting in apoptosis through CCAAT-enhancer-binding protein homologous protein (CHOP) activation. In an in vitro and in vivo model of ischemic stroke, we investigated whether hypothermia regulates the unfolded protein response of CHOP and Endoplasmic reticulum oxidoreductin-α (Ero1-α), because Ero1-α is suggested to be a downstream CHOP target. The gene expression of CHOP and Ero1-α was measured using Quantitative-PCR (Q-PCR) in rat hippocampi following global cerebral ischemia, and in hypoxic pheochromocytoma cells during normothermic (37 °C) and hypothermic (31 °C) conditions. As a result of ischemia, a significant increase in expression of CHOP and Ero1-α was observed after three, six and twelve hours of reperfusion following global ischemia. A stable increase in CHOP expression was observed throughout the time course (p < 0.01, p < 0.0001), whereas Ero1-α expression peaked at three to six hours (p < 0.0001). Induced hypothermia in hypoxia stressed PC12 cells resulted in a decreased expression of CHOP after three, six and twelve hours (p < 0.0001). On the contrary, the gene expression of Ero1-α increased as a result of hypothermia and peaked at twelve hours (p < 0.0001). Hypothermia attenuated the expression of CHOP, supporting that hypothermia suppress endoplasmic reticulum stress induced apoptosis in stroke. As hypothermia further induced up-regulation of Ero1-α, and since CHOP and Ero1-α showed differential regulation as a consequence of both disease (hypoxia) and treatment (hypothermia), we conclude that they are regulated independently.

No MeSH data available.


Related in: MedlinePlus

Control experiments performed in order to verify the usefulness of our in vitro model and to test the stability of several housekeeping genes in vitro and in vivo. PC12 cells were incubated under hypoxic conditions for 1 h, 4 h, and 24 h at either 37 °C or 31 °C. Expression levels of CHOP mRNA decreased as a consequence of hypothermia at 4 h (p < 0.05) and 24 h (p < 0.001) (a); whereas ERO1-α mRNA increased following 4 h (p < 0.05) and 24 h (p < 0.001) (b); Threshold cycle values (Ct) of four different housekeeping genes in hippocampus (c) and PC12 cells (d), revealed that Hmbs was stably expressed under hypoxia at both 31 °C and 37 °C.
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brainsci-05-00178-f002: Control experiments performed in order to verify the usefulness of our in vitro model and to test the stability of several housekeeping genes in vitro and in vivo. PC12 cells were incubated under hypoxic conditions for 1 h, 4 h, and 24 h at either 37 °C or 31 °C. Expression levels of CHOP mRNA decreased as a consequence of hypothermia at 4 h (p < 0.05) and 24 h (p < 0.001) (a); whereas ERO1-α mRNA increased following 4 h (p < 0.05) and 24 h (p < 0.001) (b); Threshold cycle values (Ct) of four different housekeeping genes in hippocampus (c) and PC12 cells (d), revealed that Hmbs was stably expressed under hypoxia at both 31 °C and 37 °C.

Mentions: Thapsigargin were used in order to verify the suitability of PC12 cells in our experimental setup. Both CHOP (Figure 2a) and ERO1-α (Figure 2b) mRNA were significantly changed following hypothermia, although in opposite directions. Quantification of four different housekeeping genes showed that Hmbs were stably expressed under all experimental conditions (Figure 2c,d).


The Hypothermic Influence on CHOP and Ero1-α in an Endoplasmic Reticulum Stress Model of Cerebral Ischemia.

Poone GK, Hasseldam H, Munkholm N, Rasmussen RS, Grønberg NV, Johansen FF - Brain Sci (2015)

Control experiments performed in order to verify the usefulness of our in vitro model and to test the stability of several housekeeping genes in vitro and in vivo. PC12 cells were incubated under hypoxic conditions for 1 h, 4 h, and 24 h at either 37 °C or 31 °C. Expression levels of CHOP mRNA decreased as a consequence of hypothermia at 4 h (p < 0.05) and 24 h (p < 0.001) (a); whereas ERO1-α mRNA increased following 4 h (p < 0.05) and 24 h (p < 0.001) (b); Threshold cycle values (Ct) of four different housekeeping genes in hippocampus (c) and PC12 cells (d), revealed that Hmbs was stably expressed under hypoxia at both 31 °C and 37 °C.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493463&req=5

brainsci-05-00178-f002: Control experiments performed in order to verify the usefulness of our in vitro model and to test the stability of several housekeeping genes in vitro and in vivo. PC12 cells were incubated under hypoxic conditions for 1 h, 4 h, and 24 h at either 37 °C or 31 °C. Expression levels of CHOP mRNA decreased as a consequence of hypothermia at 4 h (p < 0.05) and 24 h (p < 0.001) (a); whereas ERO1-α mRNA increased following 4 h (p < 0.05) and 24 h (p < 0.001) (b); Threshold cycle values (Ct) of four different housekeeping genes in hippocampus (c) and PC12 cells (d), revealed that Hmbs was stably expressed under hypoxia at both 31 °C and 37 °C.
Mentions: Thapsigargin were used in order to verify the suitability of PC12 cells in our experimental setup. Both CHOP (Figure 2a) and ERO1-α (Figure 2b) mRNA were significantly changed following hypothermia, although in opposite directions. Quantification of four different housekeeping genes showed that Hmbs were stably expressed under all experimental conditions (Figure 2c,d).

Bottom Line: As a result of ischemia, a significant increase in expression of CHOP and Ero1-α was observed after three, six and twelve hours of reperfusion following global ischemia.On the contrary, the gene expression of Ero1-α increased as a result of hypothermia and peaked at twelve hours (p < 0.0001).As hypothermia further induced up-regulation of Ero1-α, and since CHOP and Ero1-α showed differential regulation as a consequence of both disease (hypoxia) and treatment (hypothermia), we conclude that they are regulated independently.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Sciences and Biotech Research & Innovation Centre (BRIC), University of Copenhagen, 2200, Denmark. gagandipkb@hotmail.com.

ABSTRACT
Hypoxia induced endoplasmic reticulum stress causes accumulation of unfolded proteins in the endoplasmic reticulum and activates the unfolded protein response, resulting in apoptosis through CCAAT-enhancer-binding protein homologous protein (CHOP) activation. In an in vitro and in vivo model of ischemic stroke, we investigated whether hypothermia regulates the unfolded protein response of CHOP and Endoplasmic reticulum oxidoreductin-α (Ero1-α), because Ero1-α is suggested to be a downstream CHOP target. The gene expression of CHOP and Ero1-α was measured using Quantitative-PCR (Q-PCR) in rat hippocampi following global cerebral ischemia, and in hypoxic pheochromocytoma cells during normothermic (37 °C) and hypothermic (31 °C) conditions. As a result of ischemia, a significant increase in expression of CHOP and Ero1-α was observed after three, six and twelve hours of reperfusion following global ischemia. A stable increase in CHOP expression was observed throughout the time course (p < 0.01, p < 0.0001), whereas Ero1-α expression peaked at three to six hours (p < 0.0001). Induced hypothermia in hypoxia stressed PC12 cells resulted in a decreased expression of CHOP after three, six and twelve hours (p < 0.0001). On the contrary, the gene expression of Ero1-α increased as a result of hypothermia and peaked at twelve hours (p < 0.0001). Hypothermia attenuated the expression of CHOP, supporting that hypothermia suppress endoplasmic reticulum stress induced apoptosis in stroke. As hypothermia further induced up-regulation of Ero1-α, and since CHOP and Ero1-α showed differential regulation as a consequence of both disease (hypoxia) and treatment (hypothermia), we conclude that they are regulated independently.

No MeSH data available.


Related in: MedlinePlus