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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.


Collagen production and fibrotic gene expression in As2O3-treated animal models.(a) Masson trichrome staining for collagen deposition in cardiac cross-sectional parts. Collagen is indicated as blue areas, scale bar = 200 μm. (b) mRNA expression level of the fibrosis-related genes Col1a, Col3a, mmp2, mmp9. *p < 0.05, **p < 0.01, ***p < 0.001 vs. Control. Graph bars represent mean ± SEM, n = 3–5.
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f2: Collagen production and fibrotic gene expression in As2O3-treated animal models.(a) Masson trichrome staining for collagen deposition in cardiac cross-sectional parts. Collagen is indicated as blue areas, scale bar = 200 μm. (b) mRNA expression level of the fibrosis-related genes Col1a, Col3a, mmp2, mmp9. *p < 0.05, **p < 0.01, ***p < 0.001 vs. Control. Graph bars represent mean ± SEM, n = 3–5.

Mentions: Excessive production and deposition of extracellular matrix (ECM) proteins are the primary characteristic of cardiac fibrosis. To verify whether As2O3 could induce cardiac fibrosis, Masson’s trichrome staining and transmission electron microscopy were performed. Collagen production and deposition increased markedly in the As2O3-treated groups compared with the control group in both perivascular region and intramyocardial region (Fig. 2a). Meanwhile, the transmission electron microscopy images demonstrated that exposure to As2O3 (1.6mg/kg) significantly increased ECM deposition compared with the control group (Supplementary Figure 1). Additionally, qRT-PCR results revealed that the expression of pro-fibrotic genes including Col1a, Col3a, mmp2 and mmp9 was upregulated in the As2O3-treated groups (Fig. 2b). However, it should be noted that significant effects of As2O3 on cardiac fibrosis were seen only at the high-dose group, even though the same trend of changes was also observed with lower dosages.


Endothelial to mesenchymal transition contributes to arsenic-trioxide-induced cardiac fibrosis
Collagen production and fibrotic gene expression in As2O3-treated animal models.(a) Masson trichrome staining for collagen deposition in cardiac cross-sectional parts. Collagen is indicated as blue areas, scale bar = 200 μm. (b) mRNA expression level of the fibrosis-related genes Col1a, Col3a, mmp2, mmp9. *p < 0.05, **p < 0.01, ***p < 0.001 vs. Control. Graph bars represent mean ± SEM, n = 3–5.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f2: Collagen production and fibrotic gene expression in As2O3-treated animal models.(a) Masson trichrome staining for collagen deposition in cardiac cross-sectional parts. Collagen is indicated as blue areas, scale bar = 200 μm. (b) mRNA expression level of the fibrosis-related genes Col1a, Col3a, mmp2, mmp9. *p < 0.05, **p < 0.01, ***p < 0.001 vs. Control. Graph bars represent mean ± SEM, n = 3–5.
Mentions: Excessive production and deposition of extracellular matrix (ECM) proteins are the primary characteristic of cardiac fibrosis. To verify whether As2O3 could induce cardiac fibrosis, Masson’s trichrome staining and transmission electron microscopy were performed. Collagen production and deposition increased markedly in the As2O3-treated groups compared with the control group in both perivascular region and intramyocardial region (Fig. 2a). Meanwhile, the transmission electron microscopy images demonstrated that exposure to As2O3 (1.6mg/kg) significantly increased ECM deposition compared with the control group (Supplementary Figure 1). Additionally, qRT-PCR results revealed that the expression of pro-fibrotic genes including Col1a, Col3a, mmp2 and mmp9 was upregulated in the As2O3-treated groups (Fig. 2b). However, it should be noted that significant effects of As2O3 on cardiac fibrosis were seen only at the high-dose group, even though the same trend of changes was also observed with lower dosages.

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.