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IL-34 modulates rheumatoid synovial fibroblasts proliferation and migration via ERK/AKT signalling pathway
A. Elkhider1, J. Wei2, M. Al-Azab3, Y. Tang4, W. Walana5, W. Li6, B. Yuan7, Y. Ye8, G. Wang9, Y. Zhang10, X. Li11
- Department of Immunology, College of Basic Medical Science, Dalian Medical University, Liaoning, China.
- Department of Immunology, College of Basic Medical Science, Dalian Medical University, Liaoning, China.
- Department of Immunology, College of Basic Medical Science, Dalian Medical University, Liaoning, China.
- Department of Immunology, College of Basic Medical Science, Dalian Medical University, Liaoning, China.
- Department of Immunology, College of Basic Medical Science, Dalian Medical University, Liaoning, China.
- Department of Immunology, College of Basic Medical Science, Dalian Medical University, Liaoning, China.
- Department of Immunology, College of Basic Medical Science, Dalian Medical University, Liaoning, China.
- Department of Immunology, College of Basic Medical Science, Dalian Medical University, Liaoning, China.
- Department of Immunology, College of Basic Medical Science, Dalian Medical University, Liaoning, China.
- Department of Rheumatology and Immunology, The Second Affiliated Hospital of Dalian Medical University, Liaoning, China. zhangy1971@163.com
- Department of Immunology, College of Basic Medical Science, Dalian Medical University, Liaoning, China. lixia0416@dlmedu.edu.cn
CER12128
2020 Vol.38, N°3
PI 0479, PF 0487
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PMID: 31498070 [PubMed]
Received: 04/02/2019
Accepted : 11/07/2019
In Press: 27/08/2019
Published: 26/05/2020
Abstract
OBJECTIVES:
The interface between pro-inflammatory cytokines and rheumatoid synovial fibroblast (sFLS) has central effects on rheumatoid arthritis (RA). The present study aimed to explore the role of IL-34 expression as one of major cytokine implicated in RA.
METHODS:
We examined the expression of IL-34 after RA sFLS stimulated by IL-1β and TGF-β1 separately by reverse transcription polymerase chain reaction (RT-PCR). Transwell and wound closure techniques were used to detect whether IL-34 is involved in promoting cell migration. Cellular viability was determined via CCK-8 and cultural morphology assays between IL-34 downregulated group and non-transfected counterpart. We also tested the expression of VEGF gene with RT-PCR analysis and activation of the major signalling pathways by western blot in IL-34 down-regulated group, IL-1β or TGF-β1 treated groups. Propidium iodide (PI) staining and fluoresceine isothiocyanate (FITC) Annexin V and propidium iodide apoptosis assay were used to analyse cell cycle arrest and apoptosis separately in IL-34 down-regulated cells.
RESULTS:
We found that IL-1β significantly enhanced IL-34 expression, while contrarily, TGF-β1 restrained IL-34 gene expression. Transwell and wound closure techniques showed that IL-34 was involved considerably in promoting cell migration. However, IL-34 knock-down restricted sFLS migration possibly through the diminishing of MMP2 and MMP9 expression. Interestingly, IL-34 down-regulated cells exhibited significantly low cellular viability compared with the non-transfected counterpart via CCK-8 and cultural morphology assays. We found that IL-34 down-regulated cells have low VEGF gene expression compared with treated cells. PI staining showed a G0/G1 cell cycle arrest in IL-34 down-regulated cells. FITC Annexin V and propidium iodide apoptosis assay verified that IL-34 down-regulated cells induced massive apoptosis through apoptotic signalling caspase3, while IL-1β treated cells presented termination of cellular apoptosis signalled by BCL-2. Furthermore, we observed IL-34 induced activation of ERK1/2 and AKT pathways while IL-34 down-regulation significantly decreased the activation of these pathways.
CONCLUSIONS:
Our data add novel insights into the pathogenesis of RA and we suggest that IL-34 plays a dominant role in controlling migration and proliferation of sFLS. Consequently, therapeutic strategies targeting IL-34 could be a potent therapy for RA.
