Emodin induces apoptosis and autophagy of fibroblasts obtained from patient with ankylosing spondylitis

Abstract

Background

Ankylosing spondylitis (AS) is a type of rheumatoid disease, which has been reported to be associated with the excessive proliferation of fibroblasts recently. Emodin, a single component from a traditional Chinese medicine Rheum palmatum, exerts anti-inflammation and antirheumatic arthritis activities. However, could emodin be used to treat AS remains unclear? Thus, this study aimed to investigate the effect of emodin on AS.

Methods

Fibroblasts obtained from patients with AS were used in the current study. In addition, multiple cellular and molecular biology techniques such as Cell Counting Kit-8, Western blotting, flow cytometry, monodansylcadaverine staining, and immunofluorescence assay were applied as well.

Results

Emodin-induced apoptosis of fibroblasts obtained from patient with AS via increasing active caspase-9, active caspase-3, and Bax levels and downregulating Bcl-2. Meanwhile, emodin enhanced autophagy in fibroblasts via upregulation of the expression of Atg12, Atg5, and Beclin 1, which was further confirmed by monodansylcadaverine staining. As expected, autophagy inhibitor 3-methyladenine (3MA) completely reversed emodin-induced autophagy in fibroblasts. Moreover, 3MA significantly increased emodin-induced apoptosis of fibroblasts obtained from patient with AS by increasing the levels of γH2AX, active caspase-9, active caspase-3, and cleaved poly ADP-ribose polymerase.

Conclusion

Our results indicated that emodin effectively induced apoptosis and autophagy of fibroblasts obtained from patient with AS. In addition, suppression of autophagy enhanced emodin-induced apoptosis in fibroblasts. Therefore, we proposed that combination of emodin with autophagy inhibitor might be a potent strategy for improving the symptoms of AS in the future.

Keywords:

• emodin
• apoptosis
• autophagy
• 3MA
• ankylosing spondylitis

Acknowledgments

Funding was received from the Beijing Municipal Administration of Hospitals Incubating Program (PZ2016017), the Foundation for Young Scientists of Gongyan Xu and Shouren Xia (XX-201708), and the Beijing Traditional Chinese Medicine Eternal Flame Heritage Project “3+3”, The Master Laboratory of Weilan Wang (2014-SZ-A-30). Yanjing School Innova-tively Inherits “Fist” project - Rheumatology Department.

Disclosure

The authors report no conflicts of interest in this work.