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Urotensin II Protects Cardiomyocytes from Apoptosis Induced by Oxidative Stress through the CSE/H2S Pathway.

Gong H, Chen Z, Zhang X, Li Y, Zhang J, Chen Y, Ding Y, Zhang G, Yang C, Zhu Y, Zou Y - Int J Mol Sci (2015)

Bottom Line: UII pretreatment significantly reduced the number of apoptotic cardiomyocytes induced by H2O2; and it partly abolished the increase of pro-apoptotic protein Bax and the decrease of anti-apoptotic protein Bcl-2 in cardiomyocytes induced by H2O2.SiRNA targeted to the urotensin II receptor (UT) greatly inhibited these effects.In conclusion, UII rapidly promoted the phosphorylation of ERK and upregulated CSE level and H2S production, which in turn activated ERK signaling to protect cardiomyocytes from apoptosis under oxidative stress.

View Article: PubMed Central - PubMed

Affiliation: Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China. ghui1975@163.com.

ABSTRACT
Plasma urotensin II (UII) has been observed to be raised in patients with acute myocardial infarction; suggesting a possible cardiac protective role for this peptide. However, the molecular mechanism is unclear. Here, we treated cultured cardiomyocytes with H2O2 to induce oxidative stress; observed the effect of UII on H2O2-induced apoptosis and explored potential mechanisms. UII pretreatment significantly reduced the number of apoptotic cardiomyocytes induced by H2O2; and it partly abolished the increase of pro-apoptotic protein Bax and the decrease of anti-apoptotic protein Bcl-2 in cardiomyocytes induced by H2O2. SiRNA targeted to the urotensin II receptor (UT) greatly inhibited these effects. Further analysis revealed that UII increased the production of hydrogen sulfide (H2S) and the level of cystathionine-γ-lyase (CSE) by activating the ERK signaling in H2O2-treated-cardiomyocytes. Si-CSE or ERK inhibitor not only greatly inhibited the increase in CSE level or the phosphorylation of ERK induced by UII but also reversed anti-apoptosis of UII in H2O2-treated-cadiomyocytes. In conclusion, UII rapidly promoted the phosphorylation of ERK and upregulated CSE level and H2S production, which in turn activated ERK signaling to protect cardiomyocytes from apoptosis under oxidative stress. These results suggest that increased plasma UII level may protect cardiomyocytes at the early-phase of acute myocardial infarction in patients.

No MeSH data available.


Related in: MedlinePlus

UII prevents cardiomyocytes from apoptosis induced by H2O2. (A) Detection of apoptotic cardiomyocytes (brown nuclei) by TUNEL staining; (B) Quantitative analysis of TUNEL positive cells, the data were represented as the percentage of TUNEL positive nuclei; (C) Western blot analysis of the level of Bax and Bcl-2 proteins; (D) Quantitative analysis of the ratio of Bax/Bcl-2 expression. The cultured cardiomyocytes were transfected with siRNA-UT (si-UT) or siRNA-scramble (as control) for 48 h, then treated with UII (0.1 μM) or PBS for 30 min and exposed to 100 μM H2O2 for 24 h. si-UT: Cardiomyocytes were transfected with siRNA-UT. Cardiomyocytes were transfected with siRNA-scramble (si-scram) as control. Values are mean ± SEM. *p < 0.05 vs. PBS group; #p < 0.05 vs. H2O2 group; &p < 0.05 vs. H2O2 + UII group. Bar = 25 μm. All experiments were repeated independently at least three times.
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ijms-16-12482-f001: UII prevents cardiomyocytes from apoptosis induced by H2O2. (A) Detection of apoptotic cardiomyocytes (brown nuclei) by TUNEL staining; (B) Quantitative analysis of TUNEL positive cells, the data were represented as the percentage of TUNEL positive nuclei; (C) Western blot analysis of the level of Bax and Bcl-2 proteins; (D) Quantitative analysis of the ratio of Bax/Bcl-2 expression. The cultured cardiomyocytes were transfected with siRNA-UT (si-UT) or siRNA-scramble (as control) for 48 h, then treated with UII (0.1 μM) or PBS for 30 min and exposed to 100 μM H2O2 for 24 h. si-UT: Cardiomyocytes were transfected with siRNA-UT. Cardiomyocytes were transfected with siRNA-scramble (si-scram) as control. Values are mean ± SEM. *p < 0.05 vs. PBS group; #p < 0.05 vs. H2O2 group; &p < 0.05 vs. H2O2 + UII group. Bar = 25 μm. All experiments were repeated independently at least three times.

Mentions: Real-time PCR analysis showed UII mRNA expression was increased significantly in left ventricle tissues at two days after myocardial infarction (Figure S1A). We then explored whether UII can protect cardiomyocytes from apoptosis induced by oxidative stress in vitro. According to previous studies [15,16], 100 μM H2O2 was used to induce oxidative stress-related apoptosis in cardiomyocytes. First, the effect of UII (0.1 µM) [17] on apoptosis induced by H2O2 was assessed by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay (TUNEL) in cardiomyocytes. UII pre-treatment significantly reduced the number of TUNEL-positive cardiomyocytes induced by H2O2. SiRNA targeted UT (si-UT) partly abolished the anti-apoptotic effect of UII (Figure 1A,B). Bax and Bcl-2 have been reported to be a pro-apoptotic protein and an anti-apoptotic protein, respectively [18]. Western blot analysis revealed that H2O2-treated-cardiomyocytes displayed a significant increase in the level of the pro-apoptotic protein Bax and a decrease in the level of anti-apoptotic protein Bcl-2. But UII greatly prevent the effects, and si-UT significantly suppressed the decrease of Bax and the increase of Bcl-2 induced by UII in H2O2-treated-cardiomyocytes (Figure 1C,D). These data suggest that UII prevents H2O2-treated-cardiomyocytes from apoptosis by UT.


Urotensin II Protects Cardiomyocytes from Apoptosis Induced by Oxidative Stress through the CSE/H2S Pathway.

Gong H, Chen Z, Zhang X, Li Y, Zhang J, Chen Y, Ding Y, Zhang G, Yang C, Zhu Y, Zou Y - Int J Mol Sci (2015)

UII prevents cardiomyocytes from apoptosis induced by H2O2. (A) Detection of apoptotic cardiomyocytes (brown nuclei) by TUNEL staining; (B) Quantitative analysis of TUNEL positive cells, the data were represented as the percentage of TUNEL positive nuclei; (C) Western blot analysis of the level of Bax and Bcl-2 proteins; (D) Quantitative analysis of the ratio of Bax/Bcl-2 expression. The cultured cardiomyocytes were transfected with siRNA-UT (si-UT) or siRNA-scramble (as control) for 48 h, then treated with UII (0.1 μM) or PBS for 30 min and exposed to 100 μM H2O2 for 24 h. si-UT: Cardiomyocytes were transfected with siRNA-UT. Cardiomyocytes were transfected with siRNA-scramble (si-scram) as control. Values are mean ± SEM. *p < 0.05 vs. PBS group; #p < 0.05 vs. H2O2 group; &p < 0.05 vs. H2O2 + UII group. Bar = 25 μm. All experiments were repeated independently at least three times.
© Copyright Policy
Related In: Results  -  Collection

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ijms-16-12482-f001: UII prevents cardiomyocytes from apoptosis induced by H2O2. (A) Detection of apoptotic cardiomyocytes (brown nuclei) by TUNEL staining; (B) Quantitative analysis of TUNEL positive cells, the data were represented as the percentage of TUNEL positive nuclei; (C) Western blot analysis of the level of Bax and Bcl-2 proteins; (D) Quantitative analysis of the ratio of Bax/Bcl-2 expression. The cultured cardiomyocytes were transfected with siRNA-UT (si-UT) or siRNA-scramble (as control) for 48 h, then treated with UII (0.1 μM) or PBS for 30 min and exposed to 100 μM H2O2 for 24 h. si-UT: Cardiomyocytes were transfected with siRNA-UT. Cardiomyocytes were transfected with siRNA-scramble (si-scram) as control. Values are mean ± SEM. *p < 0.05 vs. PBS group; #p < 0.05 vs. H2O2 group; &p < 0.05 vs. H2O2 + UII group. Bar = 25 μm. All experiments were repeated independently at least three times.
Mentions: Real-time PCR analysis showed UII mRNA expression was increased significantly in left ventricle tissues at two days after myocardial infarction (Figure S1A). We then explored whether UII can protect cardiomyocytes from apoptosis induced by oxidative stress in vitro. According to previous studies [15,16], 100 μM H2O2 was used to induce oxidative stress-related apoptosis in cardiomyocytes. First, the effect of UII (0.1 µM) [17] on apoptosis induced by H2O2 was assessed by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay (TUNEL) in cardiomyocytes. UII pre-treatment significantly reduced the number of TUNEL-positive cardiomyocytes induced by H2O2. SiRNA targeted UT (si-UT) partly abolished the anti-apoptotic effect of UII (Figure 1A,B). Bax and Bcl-2 have been reported to be a pro-apoptotic protein and an anti-apoptotic protein, respectively [18]. Western blot analysis revealed that H2O2-treated-cardiomyocytes displayed a significant increase in the level of the pro-apoptotic protein Bax and a decrease in the level of anti-apoptotic protein Bcl-2. But UII greatly prevent the effects, and si-UT significantly suppressed the decrease of Bax and the increase of Bcl-2 induced by UII in H2O2-treated-cardiomyocytes (Figure 1C,D). These data suggest that UII prevents H2O2-treated-cardiomyocytes from apoptosis by UT.

Bottom Line: UII pretreatment significantly reduced the number of apoptotic cardiomyocytes induced by H2O2; and it partly abolished the increase of pro-apoptotic protein Bax and the decrease of anti-apoptotic protein Bcl-2 in cardiomyocytes induced by H2O2.SiRNA targeted to the urotensin II receptor (UT) greatly inhibited these effects.In conclusion, UII rapidly promoted the phosphorylation of ERK and upregulated CSE level and H2S production, which in turn activated ERK signaling to protect cardiomyocytes from apoptosis under oxidative stress.

View Article: PubMed Central - PubMed

Affiliation: Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China. ghui1975@163.com.

ABSTRACT
Plasma urotensin II (UII) has been observed to be raised in patients with acute myocardial infarction; suggesting a possible cardiac protective role for this peptide. However, the molecular mechanism is unclear. Here, we treated cultured cardiomyocytes with H2O2 to induce oxidative stress; observed the effect of UII on H2O2-induced apoptosis and explored potential mechanisms. UII pretreatment significantly reduced the number of apoptotic cardiomyocytes induced by H2O2; and it partly abolished the increase of pro-apoptotic protein Bax and the decrease of anti-apoptotic protein Bcl-2 in cardiomyocytes induced by H2O2. SiRNA targeted to the urotensin II receptor (UT) greatly inhibited these effects. Further analysis revealed that UII increased the production of hydrogen sulfide (H2S) and the level of cystathionine-γ-lyase (CSE) by activating the ERK signaling in H2O2-treated-cardiomyocytes. Si-CSE or ERK inhibitor not only greatly inhibited the increase in CSE level or the phosphorylation of ERK induced by UII but also reversed anti-apoptosis of UII in H2O2-treated-cadiomyocytes. In conclusion, UII rapidly promoted the phosphorylation of ERK and upregulated CSE level and H2S production, which in turn activated ERK signaling to protect cardiomyocytes from apoptosis under oxidative stress. These results suggest that increased plasma UII level may protect cardiomyocytes at the early-phase of acute myocardial infarction in patients.

No MeSH data available.


Related in: MedlinePlus