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Low dietary inorganic phosphate affects the lung growth of developing mice.

Xu CX, Jin H, Chung YS, Shin JY, Hwang SK, Kwon JT, Park SJ, Lee ES, Minai-Tehrani A, Chang SH, Woo MA, Noh MS, An GH, Lee KH, Cho MH - J. Vet. Sci. (2009)

Bottom Line: Therefore, current study was performed to discover the potential effects of low Pi on the lung of developing transgenic mice expressing the renilla/firefly luciferase dual reporter gene.Our results demonstrate that low Pi affects the lungs of developing mice by disturbing protein translation, the cell cycle and the expression of fibroblast growth factor-2.These results suggest that optimally regulating Pi consumption may be important to maintain health.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Toxicology, College of Veterinary Medicine, Seoul National University, Seoul, Korea.

ABSTRACT
Inorganic phosphate (Pi) plays a critical role in diverse cellular functions, and regulating the Pi balance is accomplished by sodium-dependent Pi co-transporter (NPT). Pulmonary NPT has recently been identified in mammalian lungs. However, to date, many of the studies that have involved Pi have mainly focused on its effect on bone and kidney. Therefore, current study was performed to discover the potential effects of low Pi on the lung of developing transgenic mice expressing the renilla/firefly luciferase dual reporter gene. Two-weeks old male mice divided into 2 groups and these groups were fed either a low PI diet or a normal control diet (normal: 0.5% Pi, low: 0.1% Pi) for 4 weeks. After 4 weeks of the diet, all the mice were sacrificed. Their lungs were harvested and analyzed by performing luciferase assay, Western blotting, kinase assay and immunohistochemistry. Our results demonstrate that low Pi affects the lungs of developing mice by disturbing protein translation, the cell cycle and the expression of fibroblast growth factor-2. These results suggest that optimally regulating Pi consumption may be important to maintain health.

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Western blot analysis of the mammalian target of rapamycin (mTOR), 4E-PB1 and p-4E-BP1 protein in the lungs of mice fed a low Pi diet (0.1% Pi) or a normal (0.5% Pi) diet for 4 weeks. (A) The expressions of mTOR, 4E-PB1 and p-4E-BP1 protein in the lungs. (B) The mTOR kinase activity and phosphorylation ratio for 4E-BP1 were measured in the lung homogenates. (C) The bands-of-interests were further analyzed by using a densitometer. (D) The luciferase activities were measured in the tissue homogenate from lung, and the ratios of the cap-dependent (r-luc) to the IRES dependent (f-luc) protein translation are shown. p values (*p < 0.05, **p < 0.01) indicate a significant difference compared with normal (mean ± SE, n = 4).
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Figure 3: Western blot analysis of the mammalian target of rapamycin (mTOR), 4E-PB1 and p-4E-BP1 protein in the lungs of mice fed a low Pi diet (0.1% Pi) or a normal (0.5% Pi) diet for 4 weeks. (A) The expressions of mTOR, 4E-PB1 and p-4E-BP1 protein in the lungs. (B) The mTOR kinase activity and phosphorylation ratio for 4E-BP1 were measured in the lung homogenates. (C) The bands-of-interests were further analyzed by using a densitometer. (D) The luciferase activities were measured in the tissue homogenate from lung, and the ratios of the cap-dependent (r-luc) to the IRES dependent (f-luc) protein translation are shown. p values (*p < 0.05, **p < 0.01) indicate a significant difference compared with normal (mean ± SE, n = 4).

Mentions: Our results demonstrated that low dietary Pi increased the phosphorylation of 4E-BP1, while the protein expression of mTOR was slightly increased without statistical significance (Figs. 3A and C). However, the net results were an increase of mTOR kinase activity (Fig. 3B) and facilitated cap-dependent protein translation, as was shown on the dual luciferase assay (normal group: 0.38 ± 0.12; low dietary group: 0.87 ± 0.07) (Fig. 3D).


Low dietary inorganic phosphate affects the lung growth of developing mice.

Xu CX, Jin H, Chung YS, Shin JY, Hwang SK, Kwon JT, Park SJ, Lee ES, Minai-Tehrani A, Chang SH, Woo MA, Noh MS, An GH, Lee KH, Cho MH - J. Vet. Sci. (2009)

Western blot analysis of the mammalian target of rapamycin (mTOR), 4E-PB1 and p-4E-BP1 protein in the lungs of mice fed a low Pi diet (0.1% Pi) or a normal (0.5% Pi) diet for 4 weeks. (A) The expressions of mTOR, 4E-PB1 and p-4E-BP1 protein in the lungs. (B) The mTOR kinase activity and phosphorylation ratio for 4E-BP1 were measured in the lung homogenates. (C) The bands-of-interests were further analyzed by using a densitometer. (D) The luciferase activities were measured in the tissue homogenate from lung, and the ratios of the cap-dependent (r-luc) to the IRES dependent (f-luc) protein translation are shown. p values (*p < 0.05, **p < 0.01) indicate a significant difference compared with normal (mean ± SE, n = 4).
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2801121&req=5

Figure 3: Western blot analysis of the mammalian target of rapamycin (mTOR), 4E-PB1 and p-4E-BP1 protein in the lungs of mice fed a low Pi diet (0.1% Pi) or a normal (0.5% Pi) diet for 4 weeks. (A) The expressions of mTOR, 4E-PB1 and p-4E-BP1 protein in the lungs. (B) The mTOR kinase activity and phosphorylation ratio for 4E-BP1 were measured in the lung homogenates. (C) The bands-of-interests were further analyzed by using a densitometer. (D) The luciferase activities were measured in the tissue homogenate from lung, and the ratios of the cap-dependent (r-luc) to the IRES dependent (f-luc) protein translation are shown. p values (*p < 0.05, **p < 0.01) indicate a significant difference compared with normal (mean ± SE, n = 4).
Mentions: Our results demonstrated that low dietary Pi increased the phosphorylation of 4E-BP1, while the protein expression of mTOR was slightly increased without statistical significance (Figs. 3A and C). However, the net results were an increase of mTOR kinase activity (Fig. 3B) and facilitated cap-dependent protein translation, as was shown on the dual luciferase assay (normal group: 0.38 ± 0.12; low dietary group: 0.87 ± 0.07) (Fig. 3D).

Bottom Line: Therefore, current study was performed to discover the potential effects of low Pi on the lung of developing transgenic mice expressing the renilla/firefly luciferase dual reporter gene.Our results demonstrate that low Pi affects the lungs of developing mice by disturbing protein translation, the cell cycle and the expression of fibroblast growth factor-2.These results suggest that optimally regulating Pi consumption may be important to maintain health.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Toxicology, College of Veterinary Medicine, Seoul National University, Seoul, Korea.

ABSTRACT
Inorganic phosphate (Pi) plays a critical role in diverse cellular functions, and regulating the Pi balance is accomplished by sodium-dependent Pi co-transporter (NPT). Pulmonary NPT has recently been identified in mammalian lungs. However, to date, many of the studies that have involved Pi have mainly focused on its effect on bone and kidney. Therefore, current study was performed to discover the potential effects of low Pi on the lung of developing transgenic mice expressing the renilla/firefly luciferase dual reporter gene. Two-weeks old male mice divided into 2 groups and these groups were fed either a low PI diet or a normal control diet (normal: 0.5% Pi, low: 0.1% Pi) for 4 weeks. After 4 weeks of the diet, all the mice were sacrificed. Their lungs were harvested and analyzed by performing luciferase assay, Western blotting, kinase assay and immunohistochemistry. Our results demonstrate that low Pi affects the lungs of developing mice by disturbing protein translation, the cell cycle and the expression of fibroblast growth factor-2. These results suggest that optimally regulating Pi consumption may be important to maintain health.

Show MeSH