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Emodin Inhibits Homocysteine-Induced C-Reactive Protein Generation in Vascular Smooth Muscle Cells by Regulating PPARγ Expression and ROS-ERK1/2/p38 Signal Pathway.

Pang X, Liu J, Li Y, Zhao J, Zhang X - PLoS ONE (2015)

Bottom Line: In the present study, we observed effect of emodin on Hcy-induced CRP expression in rat VSMCs and molecular mechanisms.The in vivo experiments displayed that emodin not only inhibited CRP expression in the vessel walls in mRNA and protein levels, but also reduced the circulating CRP level in hyperhomocysteinemic rats.The present study provides new evidence for the anti-inflammatory and anti-atherosclerotic effects of emodin.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology, Xi'an Jiaotong University School of Medicine, Xi'an, China; Department of Clinical Pharmacy, Central Hospital of Zibo, Zibo, China.

ABSTRACT
Atherosclerosis is an inflammatory disease. As an inflammatory molecule, C-reactive protein (CRP) plays a direct role in atherogenesis. It is known that the elevated plasma homocysteine (Hcy) level is an independent risk factor for atherosclerosis. We previously reported that Hcy produces a pro-inflammatory effect by inducing CRP expression in vascular smooth muscle cells (VSMCs). In the present study, we observed effect of emodin on Hcy-induced CRP expression in rat VSMCs and molecular mechanisms. The in vitro results showed that pretreatment of VSMCs with emodin inhibited Hcy-induced mRNA and protein expression of CRP in a concentration-dependent manner. The in vivo experiments displayed that emodin not only inhibited CRP expression in the vessel walls in mRNA and protein levels, but also reduced the circulating CRP level in hyperhomocysteinemic rats. Further study revealed that emodin diminished Hcy-stimulated generation of reactive oxygen species (ROS), attenuated Hcy-activated phosphorylation of ERK1/2 and p38, and upregulated Hcy-inhibited expression of peroxisome proliferator-activated receptor gamma (PPARγ) in VSMCs. These demonstrate that emodin is able to inhibit Hcy-induced CRP generation in VSMCs, which is related to interfering with ROS-ERK1/2/p38 signal pathway and upregulating PPARγ expression. The present study provides new evidence for the anti-inflammatory and anti-atherosclerotic effects of emodin.

No MeSH data available.


Related in: MedlinePlus

Effects of emodin on Hcy-stimulated CRP expression and ROS generation in VSMCs.The cells were preincubated with the different concentrations of emodin for 24 h before stimulation with 100 μM homocysteine (Hcy) for 12 h. mRNA (A) and protein (B) expression of CRP was identified by RT-PCR and Western blot, respectively. In another experiment, the cells were incubated with the different concentrations of emodin for 24 h and then, exposed to 100 μM Hcy for 40 min after preloaded with H2DCF-DA (10 μM) for 30 min. The fluorescent intensity was measured by a fluorescence microscope. (C) Representative fluorescence images: (a) control, (b) Hcy alone, (c) Hcy + 0.1 μM emodin, (d) Hcy + 1 μM emodin, (e) Hcy + 10 μM emodin, (f) 10 μM emodin, (g) 0.1% DMSO. (D) Relative fluorescence intensity quantified from the fluorescence images. Emodin alone was used as drug control and DMSO (0.1%) was used as solvent control. Results from three independent experiments were expressed as means ± S.E.M. *P < 0.05 vs. control, #P < 0.05 vs. Hcy alone.
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pone.0131295.g002: Effects of emodin on Hcy-stimulated CRP expression and ROS generation in VSMCs.The cells were preincubated with the different concentrations of emodin for 24 h before stimulation with 100 μM homocysteine (Hcy) for 12 h. mRNA (A) and protein (B) expression of CRP was identified by RT-PCR and Western blot, respectively. In another experiment, the cells were incubated with the different concentrations of emodin for 24 h and then, exposed to 100 μM Hcy for 40 min after preloaded with H2DCF-DA (10 μM) for 30 min. The fluorescent intensity was measured by a fluorescence microscope. (C) Representative fluorescence images: (a) control, (b) Hcy alone, (c) Hcy + 0.1 μM emodin, (d) Hcy + 1 μM emodin, (e) Hcy + 10 μM emodin, (f) 10 μM emodin, (g) 0.1% DMSO. (D) Relative fluorescence intensity quantified from the fluorescence images. Emodin alone was used as drug control and DMSO (0.1%) was used as solvent control. Results from three independent experiments were expressed as means ± S.E.M. *P < 0.05 vs. control, #P < 0.05 vs. Hcy alone.

Mentions: Fig 2A and 2B show that CRP mRNA and protein expression was increased after the exposure of VSMCs to 100 μM Hcy for 12 h. (P < 0.05 vs. control). However, pretreatment of the cells with the different concentrations of emodin (0.1, 1, 10 μM) prior to Hcy stimulation markedly inhibited Hcy-induced mRNA and protein accumulation of CRP in VSMCs in a concentration-dependent manner (P < 0.05 vs. Hcy alone). Inhibition of CRP was 34.9%, 53.3%, 70.7% for mRNA expression, and 11.9%, 38.5%, 71.8% for protein expression, respectively. In addition, emodin or DMSO (solvent control) alone did not significantly change the basal CRP expression in VSMCs.


Emodin Inhibits Homocysteine-Induced C-Reactive Protein Generation in Vascular Smooth Muscle Cells by Regulating PPARγ Expression and ROS-ERK1/2/p38 Signal Pathway.

Pang X, Liu J, Li Y, Zhao J, Zhang X - PLoS ONE (2015)

Effects of emodin on Hcy-stimulated CRP expression and ROS generation in VSMCs.The cells were preincubated with the different concentrations of emodin for 24 h before stimulation with 100 μM homocysteine (Hcy) for 12 h. mRNA (A) and protein (B) expression of CRP was identified by RT-PCR and Western blot, respectively. In another experiment, the cells were incubated with the different concentrations of emodin for 24 h and then, exposed to 100 μM Hcy for 40 min after preloaded with H2DCF-DA (10 μM) for 30 min. The fluorescent intensity was measured by a fluorescence microscope. (C) Representative fluorescence images: (a) control, (b) Hcy alone, (c) Hcy + 0.1 μM emodin, (d) Hcy + 1 μM emodin, (e) Hcy + 10 μM emodin, (f) 10 μM emodin, (g) 0.1% DMSO. (D) Relative fluorescence intensity quantified from the fluorescence images. Emodin alone was used as drug control and DMSO (0.1%) was used as solvent control. Results from three independent experiments were expressed as means ± S.E.M. *P < 0.05 vs. control, #P < 0.05 vs. Hcy alone.
© Copyright Policy
Related In: Results  -  Collection

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pone.0131295.g002: Effects of emodin on Hcy-stimulated CRP expression and ROS generation in VSMCs.The cells were preincubated with the different concentrations of emodin for 24 h before stimulation with 100 μM homocysteine (Hcy) for 12 h. mRNA (A) and protein (B) expression of CRP was identified by RT-PCR and Western blot, respectively. In another experiment, the cells were incubated with the different concentrations of emodin for 24 h and then, exposed to 100 μM Hcy for 40 min after preloaded with H2DCF-DA (10 μM) for 30 min. The fluorescent intensity was measured by a fluorescence microscope. (C) Representative fluorescence images: (a) control, (b) Hcy alone, (c) Hcy + 0.1 μM emodin, (d) Hcy + 1 μM emodin, (e) Hcy + 10 μM emodin, (f) 10 μM emodin, (g) 0.1% DMSO. (D) Relative fluorescence intensity quantified from the fluorescence images. Emodin alone was used as drug control and DMSO (0.1%) was used as solvent control. Results from three independent experiments were expressed as means ± S.E.M. *P < 0.05 vs. control, #P < 0.05 vs. Hcy alone.
Mentions: Fig 2A and 2B show that CRP mRNA and protein expression was increased after the exposure of VSMCs to 100 μM Hcy for 12 h. (P < 0.05 vs. control). However, pretreatment of the cells with the different concentrations of emodin (0.1, 1, 10 μM) prior to Hcy stimulation markedly inhibited Hcy-induced mRNA and protein accumulation of CRP in VSMCs in a concentration-dependent manner (P < 0.05 vs. Hcy alone). Inhibition of CRP was 34.9%, 53.3%, 70.7% for mRNA expression, and 11.9%, 38.5%, 71.8% for protein expression, respectively. In addition, emodin or DMSO (solvent control) alone did not significantly change the basal CRP expression in VSMCs.

Bottom Line: In the present study, we observed effect of emodin on Hcy-induced CRP expression in rat VSMCs and molecular mechanisms.The in vivo experiments displayed that emodin not only inhibited CRP expression in the vessel walls in mRNA and protein levels, but also reduced the circulating CRP level in hyperhomocysteinemic rats.The present study provides new evidence for the anti-inflammatory and anti-atherosclerotic effects of emodin.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology, Xi'an Jiaotong University School of Medicine, Xi'an, China; Department of Clinical Pharmacy, Central Hospital of Zibo, Zibo, China.

ABSTRACT
Atherosclerosis is an inflammatory disease. As an inflammatory molecule, C-reactive protein (CRP) plays a direct role in atherogenesis. It is known that the elevated plasma homocysteine (Hcy) level is an independent risk factor for atherosclerosis. We previously reported that Hcy produces a pro-inflammatory effect by inducing CRP expression in vascular smooth muscle cells (VSMCs). In the present study, we observed effect of emodin on Hcy-induced CRP expression in rat VSMCs and molecular mechanisms. The in vitro results showed that pretreatment of VSMCs with emodin inhibited Hcy-induced mRNA and protein expression of CRP in a concentration-dependent manner. The in vivo experiments displayed that emodin not only inhibited CRP expression in the vessel walls in mRNA and protein levels, but also reduced the circulating CRP level in hyperhomocysteinemic rats. Further study revealed that emodin diminished Hcy-stimulated generation of reactive oxygen species (ROS), attenuated Hcy-activated phosphorylation of ERK1/2 and p38, and upregulated Hcy-inhibited expression of peroxisome proliferator-activated receptor gamma (PPARγ) in VSMCs. These demonstrate that emodin is able to inhibit Hcy-induced CRP generation in VSMCs, which is related to interfering with ROS-ERK1/2/p38 signal pathway and upregulating PPARγ expression. The present study provides new evidence for the anti-inflammatory and anti-atherosclerotic effects of emodin.

No MeSH data available.


Related in: MedlinePlus