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Pro-fibrotic effect of IL-6 via aortic adventitial fibroblasts indicates IL-6 as a treatment target in Takayasu arteritis

1, 2, 3, 4, 5, 6, 7, 8, 9

  1. Department of Rheumatology, Zhongshan Hospital, Fudan University, Shanghai, China.
  2. Department of Rheumatology, Zhongshan Hospital, Fudan University, Shanghai, China.
  3. Department of Rheumatology, Zhongshan Hospital, Fudan University, Shanghai, China.
  4. Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China.
  5. Department of Pathology, Shanghai Medical College, Fudan University, Shanghai, China.
  6. Department of Pathology, Zhongshan Hospital, Fudan University, Shanghai, China.
  7. Key Laboratory of Glycoconjugate Research Ministry of Public Health, Gene Research Center, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China.
  8. Department of Rheumatology, Zhongshan Hospital, Fudan University, Shanghai, China.
  9. Department of Rheumatology, Zhongshan Hospital, Fudan University, Shanghai, China. zsh-rheum@hotmail.com

CER10334 Submission on line
2018 Vol.36, N°1 - PI 0062, PF 0072
Full Papers

Rheumatology Article
Rheumatology Article

 

Abstract

OBJECTIVES:
This study aimed to clarify potential mechanism of IL-6 involved in adventitial fibrosis via adventitial fibroblast in Takayasu arteritis (TAK).
METHODS:
Immunohistochemistry and double-labelled immunofluorescence were performed on vascular tissue from patients with TAK and controls. Human aorta adventitial fibroblast (AAF) was cultured and stimulated with interleukine 6 (IL-6)/IL-6 receptor (IL-6R). Real-time PCR, western blot, enzyme-linked immunosorbent assays, chromatin immunoprecipitation (ChIP) and reporter assay were conducted in vitro experiments to determine effect of IL-6/IL-6R on AAF.
RESULTS:
The expression of IL-6, IL-6R, collagen I, collagen III, fibronectin, α-smooth muscle actin (α-SMA), and transforming growth factor (TGF-β) in TAK arteries was significantly higher than that in the normal arteries. Co-localisation of α-SMA and IL-6 and a positive correlation between their expression were observed in local lesions. In vitro experiments, collagen I, collagen III, fibronectin, α-SMA, and TGF-β expression increased significantly after stimulation and this fibrogenesis of AAFs was induced in TGF-β-dependent and -independent manners. Additionally, phosphorylation of JAK2, STAT3 and Akt was significantly enhanced both in IL-6/IL-6R-treated AAFs in vitro and in TAK adventitial α-SMA positive cells. When AAFs were pretreated with inhibitors against JAK2, STAT3, and Akt, fibrosis was significantly reduced. Furthermore, IL-6/IL-6R promoted mRNA expression of IL-6 and MCP-1 in AAFs. Finally, according to ChIP and reporter assay results, STAT3 was the main transcriptional factor in the fibrosis of AAFs induced by IL-6/IL-6R.
CONCLUSIONS:
IL-6/IL-6R induces fibrogenesis of AAFs via the JAK2/STAT3 and JAK2/Akt pathways, which provides theoretical evidence for IL-6 as a treatment target in TAK.

PMID: 28770707 [PubMed]

Received: 16/02/2017 - Accepted : 18/04/2017 - In Press: 06/07/2017 - Published: 05/02/2018