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Rapamycin inhibits transforming growth factor β-induced peritoneal angiogenesis by blocking the secondary hypoxic response.

Sekiguchi Y, Zhang J, Patterson S, Liu L, Hamada C, Tomino Y, Margetts PJ - J. Cell. Mol. Med. (2012)

Bottom Line: In primary mesothelial cell culture, rapamycin had no effect on TGFβ-induced vascular endothelial growth factor (VEGF) but did suppress hypoxia-induced VEGF.The fibrogenic effects of HIF1α were Smad3 dependent.The hypoxic response is mediated partly through HIF1α and the mTOR inhibitor rapamycin blocks the hypoxic-induced angiogenic effects but does not affect the direct TGFβ-mediated fibrosis and angiogenesis.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, McMaster University, Hamilton, Ontario, Canada.

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Related in: MedlinePlus

Primary rat mesothelial cells were cultured and exposed to recombinant TGFβ1 (2.5 ng/ml) and varying concentrations of rapamycin. Cells were harvested for protein or mRNA. Supernatant was taken for VEGF ELISA. (A) Western blot for HIF1α referenced to β-actin. (B) Blots were quantified with a representative blot shown. (C) HIF1α gene expression by quantitative real time PCR referenced to GAPDH (for both protein and gene expression of HIF1α, P = NS, TGFβ versus no TGFβ and P = NS for the effect of rapamycin). (D) Cell culture supernatant was analysed for VEGF by ELISA. TGFβ1-induced VEGF expression (P < 0.001 by two-way ANOVA) and again rapamycin had no significant effect on this (N = 4 samples for each group at each time point).
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fig04: Primary rat mesothelial cells were cultured and exposed to recombinant TGFβ1 (2.5 ng/ml) and varying concentrations of rapamycin. Cells were harvested for protein or mRNA. Supernatant was taken for VEGF ELISA. (A) Western blot for HIF1α referenced to β-actin. (B) Blots were quantified with a representative blot shown. (C) HIF1α gene expression by quantitative real time PCR referenced to GAPDH (for both protein and gene expression of HIF1α, P = NS, TGFβ versus no TGFβ and P = NS for the effect of rapamycin). (D) Cell culture supernatant was analysed for VEGF by ELISA. TGFβ1-induced VEGF expression (P < 0.001 by two-way ANOVA) and again rapamycin had no significant effect on this (N = 4 samples for each group at each time point).

Mentions: We studied induction of HIF1α after 24 hrs of exposure to recombinant TGFβ1. TGFβ1 did not significantly induce HIF1α protein or gene expression at this time point (Fig. 4A–C) and HIF1α protein and gene expression was not significantly affected by rapamycin. TGFβ1 significantly increased VEGF gene expression in mesothelial cell culture and rapamycin had no effect on this (Fig. 4D).


Rapamycin inhibits transforming growth factor β-induced peritoneal angiogenesis by blocking the secondary hypoxic response.

Sekiguchi Y, Zhang J, Patterson S, Liu L, Hamada C, Tomino Y, Margetts PJ - J. Cell. Mol. Med. (2012)

Primary rat mesothelial cells were cultured and exposed to recombinant TGFβ1 (2.5 ng/ml) and varying concentrations of rapamycin. Cells were harvested for protein or mRNA. Supernatant was taken for VEGF ELISA. (A) Western blot for HIF1α referenced to β-actin. (B) Blots were quantified with a representative blot shown. (C) HIF1α gene expression by quantitative real time PCR referenced to GAPDH (for both protein and gene expression of HIF1α, P = NS, TGFβ versus no TGFβ and P = NS for the effect of rapamycin). (D) Cell culture supernatant was analysed for VEGF by ELISA. TGFβ1-induced VEGF expression (P < 0.001 by two-way ANOVA) and again rapamycin had no significant effect on this (N = 4 samples for each group at each time point).
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3822704&req=5

fig04: Primary rat mesothelial cells were cultured and exposed to recombinant TGFβ1 (2.5 ng/ml) and varying concentrations of rapamycin. Cells were harvested for protein or mRNA. Supernatant was taken for VEGF ELISA. (A) Western blot for HIF1α referenced to β-actin. (B) Blots were quantified with a representative blot shown. (C) HIF1α gene expression by quantitative real time PCR referenced to GAPDH (for both protein and gene expression of HIF1α, P = NS, TGFβ versus no TGFβ and P = NS for the effect of rapamycin). (D) Cell culture supernatant was analysed for VEGF by ELISA. TGFβ1-induced VEGF expression (P < 0.001 by two-way ANOVA) and again rapamycin had no significant effect on this (N = 4 samples for each group at each time point).
Mentions: We studied induction of HIF1α after 24 hrs of exposure to recombinant TGFβ1. TGFβ1 did not significantly induce HIF1α protein or gene expression at this time point (Fig. 4A–C) and HIF1α protein and gene expression was not significantly affected by rapamycin. TGFβ1 significantly increased VEGF gene expression in mesothelial cell culture and rapamycin had no effect on this (Fig. 4D).

Bottom Line: In primary mesothelial cell culture, rapamycin had no effect on TGFβ-induced vascular endothelial growth factor (VEGF) but did suppress hypoxia-induced VEGF.The fibrogenic effects of HIF1α were Smad3 dependent.The hypoxic response is mediated partly through HIF1α and the mTOR inhibitor rapamycin blocks the hypoxic-induced angiogenic effects but does not affect the direct TGFβ-mediated fibrosis and angiogenesis.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, McMaster University, Hamilton, Ontario, Canada.

Show MeSH
Related in: MedlinePlus