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Transgenic mouse model for imaging of ATF4 translational activation-related cellular stress responses in vivo

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ABSTRACT

Activating transcription factor 4 (ATF4) is a translationally activated protein that plays a role in cellular adaptation to several stresses. Because these stresses are associated with various diseases, the translational control of ATF4 needs to be evaluated from the physiological and pathological points of view. We have developed a transgenic mouse model to monitor the translational activation of ATF4 in response to cellular stress. By using this mouse model, we were able to detect nutrient starvation response, antivirus response, endoplasmic reticulum (ER) stress response, and oxidative stress in vitro and ex vivo, as well as in vivo. The reporter system introduced into our mouse model was also shown to work in a stress intensity-dependent manner and a stress duration-dependent manner. The mouse model is therefore a useful tool for imaging ATF4 translational activation at various levels, from cell cultures to whole bodies, and it has a range of useful applications in investigations on the physiological and pathological roles of ATF4-related stress and in the development of clinical drugs for treating ATF4-associated diseases.

No MeSH data available.


Evaluation of the ISR by using UMAI MEFs.(a) Luciferase activity in UMAI MEFs treated with the indicated concentration of leucine (Leu), poly(I)poly(C) nucleotide (pIC), tunicamycin (Tun), or sodium arsenite (ASN) for 6 h. (b) Luciferase activity in UMAI MEFs treated with Leu (−), pIC, Tun, and ASN for the indicated time. (c) Luciferase activity in UMAI MEFs treated with Leu (−), pIC, Tun, and ASN for 6 h and then cultured in a normal medium for the indicated time. Each graph is shown as mean (plot or column) ± S.E.M (error bar) from triplicate experiments.
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f5: Evaluation of the ISR by using UMAI MEFs.(a) Luciferase activity in UMAI MEFs treated with the indicated concentration of leucine (Leu), poly(I)poly(C) nucleotide (pIC), tunicamycin (Tun), or sodium arsenite (ASN) for 6 h. (b) Luciferase activity in UMAI MEFs treated with Leu (−), pIC, Tun, and ASN for the indicated time. (c) Luciferase activity in UMAI MEFs treated with Leu (−), pIC, Tun, and ASN for 6 h and then cultured in a normal medium for the indicated time. Each graph is shown as mean (plot or column) ± S.E.M (error bar) from triplicate experiments.

Mentions: By using mouse embryonic fibroblasts (MEFs) derived from this UMAI line, we were able to obtain data on how UMAI activity varied with the intensity and duration of stress treatment. UMAI activity was found to change widely in the ranges of the following stress intensity: Leu (0.01–0.8 mM), pIC (1–100 μg/mL), Tun (0.1–10 μg/mL), and ASN (0.1–10 μM) (Fig. 5a). Under all conditions [Leu (−), pIC (+), Tun (+), and ASN (+)], the UMAI activity reached a peak 4–6 hours after the initiation of stress treatment (Fig. 5b), and reverted to the basal line 8 hours after removal of the stress (Fig. 5c). These UMAI activities were well correlated with both the expression level of endogenous ATF4 protein and the phosphorylation level of endogenous eIF2α (Figs S9 and S10).


Transgenic mouse model for imaging of ATF4 translational activation-related cellular stress responses in vivo
Evaluation of the ISR by using UMAI MEFs.(a) Luciferase activity in UMAI MEFs treated with the indicated concentration of leucine (Leu), poly(I)poly(C) nucleotide (pIC), tunicamycin (Tun), or sodium arsenite (ASN) for 6 h. (b) Luciferase activity in UMAI MEFs treated with Leu (−), pIC, Tun, and ASN for the indicated time. (c) Luciferase activity in UMAI MEFs treated with Leu (−), pIC, Tun, and ASN for 6 h and then cultured in a normal medium for the indicated time. Each graph is shown as mean (plot or column) ± S.E.M (error bar) from triplicate experiments.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
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getmorefigures.php?uid=PMC5384252&req=5

f5: Evaluation of the ISR by using UMAI MEFs.(a) Luciferase activity in UMAI MEFs treated with the indicated concentration of leucine (Leu), poly(I)poly(C) nucleotide (pIC), tunicamycin (Tun), or sodium arsenite (ASN) for 6 h. (b) Luciferase activity in UMAI MEFs treated with Leu (−), pIC, Tun, and ASN for the indicated time. (c) Luciferase activity in UMAI MEFs treated with Leu (−), pIC, Tun, and ASN for 6 h and then cultured in a normal medium for the indicated time. Each graph is shown as mean (plot or column) ± S.E.M (error bar) from triplicate experiments.
Mentions: By using mouse embryonic fibroblasts (MEFs) derived from this UMAI line, we were able to obtain data on how UMAI activity varied with the intensity and duration of stress treatment. UMAI activity was found to change widely in the ranges of the following stress intensity: Leu (0.01–0.8 mM), pIC (1–100 μg/mL), Tun (0.1–10 μg/mL), and ASN (0.1–10 μM) (Fig. 5a). Under all conditions [Leu (−), pIC (+), Tun (+), and ASN (+)], the UMAI activity reached a peak 4–6 hours after the initiation of stress treatment (Fig. 5b), and reverted to the basal line 8 hours after removal of the stress (Fig. 5c). These UMAI activities were well correlated with both the expression level of endogenous ATF4 protein and the phosphorylation level of endogenous eIF2α (Figs S9 and S10).

View Article: PubMed Central - PubMed

ABSTRACT

Activating transcription factor 4 (ATF4) is a translationally activated protein that plays a role in cellular adaptation to several stresses. Because these stresses are associated with various diseases, the translational control of ATF4 needs to be evaluated from the physiological and pathological points of view. We have developed a transgenic mouse model to monitor the translational activation of ATF4 in response to cellular stress. By using this mouse model, we were able to detect nutrient starvation response, antivirus response, endoplasmic reticulum (ER) stress response, and oxidative stress in vitro and ex vivo, as well as in vivo. The reporter system introduced into our mouse model was also shown to work in a stress intensity-dependent manner and a stress duration-dependent manner. The mouse model is therefore a useful tool for imaging ATF4 translational activation at various levels, from cell cultures to whole bodies, and it has a range of useful applications in investigations on the physiological and pathological roles of ATF4-related stress and in the development of clinical drugs for treating ATF4-associated diseases.

No MeSH data available.