Limits...
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 promotes the activation of ERK in cultured cardiomyocytes exposed to H2O2. (A) Western blot analysis of p-ERK level in cultured cardiomyocytes treated with UII at different time points (0, 10, 30, 60, 120, 240 min); (B) Western blot analysis of p-ERK level in cardiomyocytes; (C) Quantitative analysis of p-ERK/ERK level in cultured cardiomyocytes. Cardiomyocytes were transfected with si-UT or siRNA-scramble for 48 h, then treated with UII (0.1 μM) or PBS for 30 min and exposed to 100 μM H2O2 for 10 min. si-UT: CMs were transfected with siRNA-UT, other CMs were transfected with siRNA-scramble (si-scram) as control. Values are mean ± SEM. &p < 0.05 vs. PBS group. *p < 0.05, **p < 0.01 vs. H2O2 group; #p < 0.05 vs. H2O2 + UII group. All experiments were repeated independently at least three times.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4490456&req=5

ijms-16-12482-f003: UII promotes the activation of ERK in cultured cardiomyocytes exposed to H2O2. (A) Western blot analysis of p-ERK level in cultured cardiomyocytes treated with UII at different time points (0, 10, 30, 60, 120, 240 min); (B) Western blot analysis of p-ERK level in cardiomyocytes; (C) Quantitative analysis of p-ERK/ERK level in cultured cardiomyocytes. Cardiomyocytes were transfected with si-UT or siRNA-scramble for 48 h, then treated with UII (0.1 μM) or PBS for 30 min and exposed to 100 μM H2O2 for 10 min. si-UT: CMs were transfected with siRNA-UT, other CMs were transfected with siRNA-scramble (si-scram) as control. Values are mean ± SEM. &p < 0.05 vs. PBS group. *p < 0.05, **p < 0.01 vs. H2O2 group; #p < 0.05 vs. H2O2 + UII group. All experiments were repeated independently at least three times.

Mentions: It has been reported that UII activates ERK to induce cardiomyocytes hypertrophy [21]. ERK is involved in cardioprotection against ischemia [37,38]. The study showed that p-ERK was greatly increased in ventricular tissue at two days after myocardial infarction (Figure S1B,D). To explore whether it is involved in the effect of UII on H2S production, we detected the p-ERK level in cardiomyocytes. UII increased p-ERK level in cultured cardiomyocytes in a time-dependent manner (Figure 3A). The level of p-ERK was slightly increased by H2O2 treatment, but it was greatly upregulated by UII, and the effect was significantly inhibited by si-UT in H2O2-treated-cardiomyocytes (Figure 3B,C). From our data, we speculate that UII-promoted-activation of ERK may contribute to the increased CSE level and subsequently upregulated endogenous H2S production to protect cardiomyocytes against H2O2. ERK, one of the important mediators of signal transduction from the cell membrane to cytosol or nucleus, is activated by multiple stimuli including ischemia [39,40]. The increased UII level in ischemic heart tissue may be involved in the activation of ERK mediated by the UT pathway. UT (GPR14) belongs to the GPCR family, which is involved in the activation of ERK with multiple mechanisms. G-protein dependent signals probably promotes epidermal growth factor receptor (EGFR) transactivation and then leads to activation of ERK, accounting for the stimulation of Elk1-dependent transcription [41]. In contrast, upon the activation of GPCRs, the binding of cytosolic β-arrestins to ERKs induces the activation of ERK, which may phosphorylate cytosolic kinases involved in multiple regulation [41]. Esposito et al. [42] reported that UII induced translocation of β-arrestin 1/2 and EGFR phosphorylation which contributes to the activation of ERK, promoting cell survival and cardioprotection during pressure overload. The activation of integrin-mediated signaling pathways has been reported to be involved in UII-induced phosphorylation of ERK in vascular smooth muscle cells (VSMCs) [43]. In addition, extracellular superoxide dismutase (SOD3) induces ERK activation, which decreases apoptosis in a rat hind limb injury model [40] or in the late stages of the aortopathy [44]. In the present study, UII may activate the ERK pathway through these mechanisms; whether other pathways are involved in the process needs further study.


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 promotes the activation of ERK in cultured cardiomyocytes exposed to H2O2. (A) Western blot analysis of p-ERK level in cultured cardiomyocytes treated with UII at different time points (0, 10, 30, 60, 120, 240 min); (B) Western blot analysis of p-ERK level in cardiomyocytes; (C) Quantitative analysis of p-ERK/ERK level in cultured cardiomyocytes. Cardiomyocytes were transfected with si-UT or siRNA-scramble for 48 h, then treated with UII (0.1 μM) or PBS for 30 min and exposed to 100 μM H2O2 for 10 min. si-UT: CMs were transfected with siRNA-UT, other CMs were transfected with siRNA-scramble (si-scram) as control. Values are mean ± SEM. &p < 0.05 vs. PBS group. *p < 0.05, **p < 0.01 vs. H2O2 group; #p < 0.05 vs. H2O2 + UII group. All experiments were repeated independently at least three times.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4490456&req=5

ijms-16-12482-f003: UII promotes the activation of ERK in cultured cardiomyocytes exposed to H2O2. (A) Western blot analysis of p-ERK level in cultured cardiomyocytes treated with UII at different time points (0, 10, 30, 60, 120, 240 min); (B) Western blot analysis of p-ERK level in cardiomyocytes; (C) Quantitative analysis of p-ERK/ERK level in cultured cardiomyocytes. Cardiomyocytes were transfected with si-UT or siRNA-scramble for 48 h, then treated with UII (0.1 μM) or PBS for 30 min and exposed to 100 μM H2O2 for 10 min. si-UT: CMs were transfected with siRNA-UT, other CMs were transfected with siRNA-scramble (si-scram) as control. Values are mean ± SEM. &p < 0.05 vs. PBS group. *p < 0.05, **p < 0.01 vs. H2O2 group; #p < 0.05 vs. H2O2 + UII group. All experiments were repeated independently at least three times.
Mentions: It has been reported that UII activates ERK to induce cardiomyocytes hypertrophy [21]. ERK is involved in cardioprotection against ischemia [37,38]. The study showed that p-ERK was greatly increased in ventricular tissue at two days after myocardial infarction (Figure S1B,D). To explore whether it is involved in the effect of UII on H2S production, we detected the p-ERK level in cardiomyocytes. UII increased p-ERK level in cultured cardiomyocytes in a time-dependent manner (Figure 3A). The level of p-ERK was slightly increased by H2O2 treatment, but it was greatly upregulated by UII, and the effect was significantly inhibited by si-UT in H2O2-treated-cardiomyocytes (Figure 3B,C). From our data, we speculate that UII-promoted-activation of ERK may contribute to the increased CSE level and subsequently upregulated endogenous H2S production to protect cardiomyocytes against H2O2. ERK, one of the important mediators of signal transduction from the cell membrane to cytosol or nucleus, is activated by multiple stimuli including ischemia [39,40]. The increased UII level in ischemic heart tissue may be involved in the activation of ERK mediated by the UT pathway. UT (GPR14) belongs to the GPCR family, which is involved in the activation of ERK with multiple mechanisms. G-protein dependent signals probably promotes epidermal growth factor receptor (EGFR) transactivation and then leads to activation of ERK, accounting for the stimulation of Elk1-dependent transcription [41]. In contrast, upon the activation of GPCRs, the binding of cytosolic β-arrestins to ERKs induces the activation of ERK, which may phosphorylate cytosolic kinases involved in multiple regulation [41]. Esposito et al. [42] reported that UII induced translocation of β-arrestin 1/2 and EGFR phosphorylation which contributes to the activation of ERK, promoting cell survival and cardioprotection during pressure overload. The activation of integrin-mediated signaling pathways has been reported to be involved in UII-induced phosphorylation of ERK in vascular smooth muscle cells (VSMCs) [43]. In addition, extracellular superoxide dismutase (SOD3) induces ERK activation, which decreases apoptosis in a rat hind limb injury model [40] or in the late stages of the aortopathy [44]. In the present study, UII may activate the ERK pathway through these mechanisms; whether other pathways are involved in the process needs further study.

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