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Local Augmented Angiotensinogen Secreted from Apoptotic Vascular Endothelial Cells Is a Vital Mediator of Vascular Remodelling.

Wu SJ, Soulez M, Yang YH, Chu CS, Shih SC, Hébert MJ, Kuo MC, Hsieh YJ - PLoS ONE (2015)

Bottom Line: After the cells were subjected to SS, we found that the mRNA expression of angiotensinogen (AGT) was increased by >3-fold in HUVECs and by approximately 2.5-fold in VSMCs.Increases in the expression of AGT protein and angiotensin II (Ang II) were found in a serum-free medium conditioned by HUVECs (SSC).In conclusion, we first demonstrated that the augmented AGT released from apoptotic endothelial cells acts as a vital progenitor of Ang II to accelerate vascular remodelling, and we suggest that blocking local augmented Ang II might be an effective strategy for restraining intimal hyperplasia.

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Laboratory Science and Biotechnology, Kaohsiung Medical University, Kaohsiung, Taiwan.

ABSTRACT
Vascular remodelling is a critical vasculopathy found in atheromatous diseases and allograft failures. The local renin angiotensin system (RAS) has been implicated in vascular remodelling. However, the mechanisms by which the augmented local RAS is associated with the initial event of endothelial cell apoptosis in injured vasculature remain undefined. We induced the apoptosis of human umbilical vein endothelial cells (HUVECs) and vascular smooth muscle cells (VSMCs) through serum starvation (SS). After the cells were subjected to SS, we found that the mRNA expression of angiotensinogen (AGT) was increased by >3-fold in HUVECs and by approximately 2.5-fold in VSMCs. In addition, the expression of angiotensin-converting enzyme (ACE) mRNA was increased in VSMCs but decreased to 50% in HUVECs during the same apoptotic process. Increases in the expression of AGT protein and angiotensin II (Ang II) were found in a serum-free medium conditioned by HUVECs (SSC). The increased Ang II was suppressed using lisinopril (an ACE inhibitor) treatment. Moreover, the activation of ERK1/2 induced by the SSC in VSMCs was also suppressed by losartan. In conclusion, we first demonstrated that the augmented AGT released from apoptotic endothelial cells acts as a vital progenitor of Ang II to accelerate vascular remodelling, and we suggest that blocking local augmented Ang II might be an effective strategy for restraining intimal hyperplasia.

No MeSH data available.


Related in: MedlinePlus

Promoter activity assay of human AGT and ACE genes in VSMCs.(A) Schematic diagrams of the reporter gene constructs. The AGT promoter (-614 to +41) and ACE promoter region (-760 to +130) were cloned into the upstream of the SEAP gene to generate the pAGT-proSEAP and pACE-proSEAP constructs, respectively. (B) SS treatment regulates the transcriptional activity of AGT and ACE promoters in VSMCs. pGL-4 was used as an internal control and contransfected with pAGT-proSEAP or pACE-proSEAP constructs in VSMCs. The relative SEAP/pGL-4 ratios represent SEAP activity normalised according to the firefly luciferase activity. The ratio in the normal medium was designated as 100%, and the values are expressed as the mean ± SE from at least 3 independent experiments. **P < 0.01 in comparison to cells cultured in a normal medium.
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pone.0132583.g004: Promoter activity assay of human AGT and ACE genes in VSMCs.(A) Schematic diagrams of the reporter gene constructs. The AGT promoter (-614 to +41) and ACE promoter region (-760 to +130) were cloned into the upstream of the SEAP gene to generate the pAGT-proSEAP and pACE-proSEAP constructs, respectively. (B) SS treatment regulates the transcriptional activity of AGT and ACE promoters in VSMCs. pGL-4 was used as an internal control and contransfected with pAGT-proSEAP or pACE-proSEAP constructs in VSMCs. The relative SEAP/pGL-4 ratios represent SEAP activity normalised according to the firefly luciferase activity. The ratio in the normal medium was designated as 100%, and the values are expressed as the mean ± SE from at least 3 independent experiments. **P < 0.01 in comparison to cells cultured in a normal medium.

Mentions: To confirm that the transcriptional activity of AGT and ACE genes is regulated by SS, we conducted a transient transfection in VSMCs by using reporter vectors cloned with the promoter region of an AGT and ACE, respectively (Fig 4A). After the cells were incubated in a normal or SS medium for 24 h, the transcriptional activity of both promoters was enhanced by SS in VSMCs (Fig 4B).


Local Augmented Angiotensinogen Secreted from Apoptotic Vascular Endothelial Cells Is a Vital Mediator of Vascular Remodelling.

Wu SJ, Soulez M, Yang YH, Chu CS, Shih SC, Hébert MJ, Kuo MC, Hsieh YJ - PLoS ONE (2015)

Promoter activity assay of human AGT and ACE genes in VSMCs.(A) Schematic diagrams of the reporter gene constructs. The AGT promoter (-614 to +41) and ACE promoter region (-760 to +130) were cloned into the upstream of the SEAP gene to generate the pAGT-proSEAP and pACE-proSEAP constructs, respectively. (B) SS treatment regulates the transcriptional activity of AGT and ACE promoters in VSMCs. pGL-4 was used as an internal control and contransfected with pAGT-proSEAP or pACE-proSEAP constructs in VSMCs. The relative SEAP/pGL-4 ratios represent SEAP activity normalised according to the firefly luciferase activity. The ratio in the normal medium was designated as 100%, and the values are expressed as the mean ± SE from at least 3 independent experiments. **P < 0.01 in comparison to cells cultured in a normal medium.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4492977&req=5

pone.0132583.g004: Promoter activity assay of human AGT and ACE genes in VSMCs.(A) Schematic diagrams of the reporter gene constructs. The AGT promoter (-614 to +41) and ACE promoter region (-760 to +130) were cloned into the upstream of the SEAP gene to generate the pAGT-proSEAP and pACE-proSEAP constructs, respectively. (B) SS treatment regulates the transcriptional activity of AGT and ACE promoters in VSMCs. pGL-4 was used as an internal control and contransfected with pAGT-proSEAP or pACE-proSEAP constructs in VSMCs. The relative SEAP/pGL-4 ratios represent SEAP activity normalised according to the firefly luciferase activity. The ratio in the normal medium was designated as 100%, and the values are expressed as the mean ± SE from at least 3 independent experiments. **P < 0.01 in comparison to cells cultured in a normal medium.
Mentions: To confirm that the transcriptional activity of AGT and ACE genes is regulated by SS, we conducted a transient transfection in VSMCs by using reporter vectors cloned with the promoter region of an AGT and ACE, respectively (Fig 4A). After the cells were incubated in a normal or SS medium for 24 h, the transcriptional activity of both promoters was enhanced by SS in VSMCs (Fig 4B).

Bottom Line: After the cells were subjected to SS, we found that the mRNA expression of angiotensinogen (AGT) was increased by >3-fold in HUVECs and by approximately 2.5-fold in VSMCs.Increases in the expression of AGT protein and angiotensin II (Ang II) were found in a serum-free medium conditioned by HUVECs (SSC).In conclusion, we first demonstrated that the augmented AGT released from apoptotic endothelial cells acts as a vital progenitor of Ang II to accelerate vascular remodelling, and we suggest that blocking local augmented Ang II might be an effective strategy for restraining intimal hyperplasia.

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Laboratory Science and Biotechnology, Kaohsiung Medical University, Kaohsiung, Taiwan.

ABSTRACT
Vascular remodelling is a critical vasculopathy found in atheromatous diseases and allograft failures. The local renin angiotensin system (RAS) has been implicated in vascular remodelling. However, the mechanisms by which the augmented local RAS is associated with the initial event of endothelial cell apoptosis in injured vasculature remain undefined. We induced the apoptosis of human umbilical vein endothelial cells (HUVECs) and vascular smooth muscle cells (VSMCs) through serum starvation (SS). After the cells were subjected to SS, we found that the mRNA expression of angiotensinogen (AGT) was increased by >3-fold in HUVECs and by approximately 2.5-fold in VSMCs. In addition, the expression of angiotensin-converting enzyme (ACE) mRNA was increased in VSMCs but decreased to 50% in HUVECs during the same apoptotic process. Increases in the expression of AGT protein and angiotensin II (Ang II) were found in a serum-free medium conditioned by HUVECs (SSC). The increased Ang II was suppressed using lisinopril (an ACE inhibitor) treatment. Moreover, the activation of ERK1/2 induced by the SSC in VSMCs was also suppressed by losartan. In conclusion, we first demonstrated that the augmented AGT released from apoptotic endothelial cells acts as a vital progenitor of Ang II to accelerate vascular remodelling, and we suggest that blocking local augmented Ang II might be an effective strategy for restraining intimal hyperplasia.

No MeSH data available.


Related in: MedlinePlus