Limits...
Endothelial to mesenchymal transition contributes to arsenic-trioxide-induced cardiac fibrosis

View Article: PubMed Central - PubMed

ABSTRACT

Emerging evidence has suggested the critical role of endothelial to mesenchymal transition (EndMT) in fibrotic diseases. The present study was designed to examine whether EndMT is involved in arsenic trioxide (As2O3)-induced cardiac fibrosis and to explore the underlying mechanisms. Cardiac dysfunction was observed in rats after exposure to As2O3 for 15 days using echocardiography, and the deposition of collagen was detected by Masson’s trichrome staining and electron microscope. EndMT was indicated by the loss of endothelial cell markers (VE-cadherin and CD31) and the acquisition of mesenchymal cell markers (α-SMA and FSP1) determined by RT-PCR at the mRNA level and Western blot and immunofluorescence analysis at the protein level. In the in-vitro experiments, endothelial cells acquired a spindle-shaped morphology accompanying downregulation of the endothelial cell markers and upregulation of the mesenchymal cell markers when exposed to As2O3. As2O3 activated the AKT/GSK-3β/Snail signaling pathway, and blocking this pathway with PI3K inhibitor (LY294002) abolished EndMT in As2O3-treated endothelial cells. Our results highlight that As2O3 is an EndMT-promoting factor during cardiac fibrosis, suggesting that targeting EndMT is beneficial for preventing As2O3-induced cardiac toxicity.

No MeSH data available.


Effects of the PI3K inhibitor LY294002 on the AKT/GSK-3β/Snail pathway and EndMT phenotypes in HAECs.(a) Before treatment with As2O3 (8 μmol/l), HAECs were pretreated with LY294002 for 2 h. The activation of AKT and GSK-3β and the expression of snail were analyzed by western blotting. +LY294002 indicates the co-application of LY294002 and As2O3 (8 μmol/l). (b) Relative mRNA level of AKT, GSK-3β and snail in different groups. *p < 0.05, **p < 0.01, ***p < 0.001 vs. Control. #p < 0.05, ##p < 0.01, ###p < 0.001 vs. As2O3. Data are shown as mean ± SEM, n = 3–5. (c) Effects of LY294002 on the morphologic phenotype of HAECs.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC5037371&req=5

f6: Effects of the PI3K inhibitor LY294002 on the AKT/GSK-3β/Snail pathway and EndMT phenotypes in HAECs.(a) Before treatment with As2O3 (8 μmol/l), HAECs were pretreated with LY294002 for 2 h. The activation of AKT and GSK-3β and the expression of snail were analyzed by western blotting. +LY294002 indicates the co-application of LY294002 and As2O3 (8 μmol/l). (b) Relative mRNA level of AKT, GSK-3β and snail in different groups. *p < 0.05, **p < 0.01, ***p < 0.001 vs. Control. #p < 0.05, ##p < 0.01, ###p < 0.001 vs. As2O3. Data are shown as mean ± SEM, n = 3–5. (c) Effects of LY294002 on the morphologic phenotype of HAECs.

Mentions: To clarify the role of the AKT/ GSK-3β/Snail pathway in As2O3-induced EndMT, LY294002 (an inhibitor of PI3K/AKT) was used to treat HAECs prior to As2O3 treatment. As shown in Fig. 6a, the expression levels of phosphorylated AKT, phosphorylated GSK-3β and Snail were markedly increased after As2O3 treatment, whereas these effects were prevented upon pre-treatment with LY294002 in combination with As2O3 in HAECs. But the protein and mRNA level of AKT and GSK-3β were not affected by LY294002 (Fig. 6a,b). Notably, we found that pre-treatment with LY294002 abrogated the morphological conversion of HAECs induced by As2O3 (Fig. 6c). While LY294002 applied alone did not exert much influence on cells phenotype in comparison to control group.


Endothelial to mesenchymal transition contributes to arsenic-trioxide-induced cardiac fibrosis
Effects of the PI3K inhibitor LY294002 on the AKT/GSK-3β/Snail pathway and EndMT phenotypes in HAECs.(a) Before treatment with As2O3 (8 μmol/l), HAECs were pretreated with LY294002 for 2 h. The activation of AKT and GSK-3β and the expression of snail were analyzed by western blotting. +LY294002 indicates the co-application of LY294002 and As2O3 (8 μmol/l). (b) Relative mRNA level of AKT, GSK-3β and snail in different groups. *p < 0.05, **p < 0.01, ***p < 0.001 vs. Control. #p < 0.05, ##p < 0.01, ###p < 0.001 vs. As2O3. Data are shown as mean ± SEM, n = 3–5. (c) Effects of LY294002 on the morphologic phenotype of HAECs.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5037371&req=5

f6: Effects of the PI3K inhibitor LY294002 on the AKT/GSK-3β/Snail pathway and EndMT phenotypes in HAECs.(a) Before treatment with As2O3 (8 μmol/l), HAECs were pretreated with LY294002 for 2 h. The activation of AKT and GSK-3β and the expression of snail were analyzed by western blotting. +LY294002 indicates the co-application of LY294002 and As2O3 (8 μmol/l). (b) Relative mRNA level of AKT, GSK-3β and snail in different groups. *p < 0.05, **p < 0.01, ***p < 0.001 vs. Control. #p < 0.05, ##p < 0.01, ###p < 0.001 vs. As2O3. Data are shown as mean ± SEM, n = 3–5. (c) Effects of LY294002 on the morphologic phenotype of HAECs.
Mentions: To clarify the role of the AKT/ GSK-3β/Snail pathway in As2O3-induced EndMT, LY294002 (an inhibitor of PI3K/AKT) was used to treat HAECs prior to As2O3 treatment. As shown in Fig. 6a, the expression levels of phosphorylated AKT, phosphorylated GSK-3β and Snail were markedly increased after As2O3 treatment, whereas these effects were prevented upon pre-treatment with LY294002 in combination with As2O3 in HAECs. But the protein and mRNA level of AKT and GSK-3β were not affected by LY294002 (Fig. 6a,b). Notably, we found that pre-treatment with LY294002 abrogated the morphological conversion of HAECs induced by As2O3 (Fig. 6c). While LY294002 applied alone did not exert much influence on cells phenotype in comparison to control group.

View Article: PubMed Central - PubMed

ABSTRACT

Emerging evidence has suggested the critical role of endothelial to mesenchymal transition (EndMT) in fibrotic diseases. The present study was designed to examine whether EndMT is involved in arsenic trioxide (As2O3)-induced cardiac fibrosis and to explore the underlying mechanisms. Cardiac dysfunction was observed in rats after exposure to As2O3 for 15&thinsp;days using echocardiography, and the deposition of collagen was detected by Masson&rsquo;s trichrome staining and electron microscope. EndMT was indicated by the loss of endothelial cell markers (VE-cadherin and CD31) and the acquisition of mesenchymal cell markers (&alpha;-SMA and FSP1) determined by RT-PCR at the mRNA level and Western blot and immunofluorescence analysis at the protein level. In the in-vitro experiments, endothelial cells acquired a spindle-shaped morphology accompanying downregulation of the endothelial cell markers and upregulation of the mesenchymal cell markers when exposed to As2O3. As2O3 activated the AKT/GSK-3&beta;/Snail signaling pathway, and blocking this pathway with PI3K inhibitor (LY294002) abolished EndMT in As2O3-treated endothelial cells. Our results highlight that As2O3 is an EndMT-promoting factor during cardiac fibrosis, suggesting that targeting EndMT is beneficial for preventing As2O3-induced cardiac toxicity.

No MeSH data available.