Abnormal PTPN11 enhancer methylation promotes rheumatoid arthritis fibroblast-like synoviocyte aggressiveness and joint inflammation
Keisuke Maeshima, … , Nunzio Bottini, Gary S. Firestein
Keisuke Maeshima, … , Nunzio Bottini, Gary S. Firestein
Published May 19, 2016
Citation Information: JCI Insight. 2016;1(7):e86580. https://doi.org/10.1172/jci.insight.86580.
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Research Article Inflammation

Abnormal PTPN11 enhancer methylation promotes rheumatoid arthritis fibroblast-like synoviocyte aggressiveness and joint inflammation

Abstract

The PTPN11 gene, encoding the tyrosine phosphatase SHP-2, is overexpressed in rheumatoid arthritis (RA) fibroblast-like synoviocytes (FLS) compared with osteoarthritis (OA) FLS and promotes RA FLS invasiveness. Here, we explored the molecular basis for PTPN11 overexpression in RA FLS and the role of SHP-2 in RA pathogenesis. Using computational methods, we identified a putative enhancer in PTPN11 intron 1, which contained a glucocorticoid receptor–binding (GR-binding) motif. This region displayed enhancer function in RA FLS and contained 2 hypermethylation sites in RA compared with OA FLS. RA FLS stimulation with the glucocorticoid dexamethasone induced GR binding to the enhancer and PTPN11 expression. Glucocorticoid responsiveness of PTPN11 was significantly higher in RA FLS than OA FLS and required the differentially methylated CpGs for full enhancer function. SHP-2 expression was enriched in the RA synovial lining, and heterozygous Ptpn11 deletion in radioresistant or innate immune cells attenuated K/BxN serum transfer arthritis in mice. Treatment with SHP-2 inhibitor 11a-1 reduced RA FLS migration and responsiveness to TNF and IL-1β stimulation and reduced arthritis severity in mice. Our findings demonstrate how abnormal epigenetic regulation of a pathogenic gene determines FLS behavior and demonstrate that targeting SHP-2 or the SHP-2 pathway could be a therapeutic strategy for RA.

Authors

Keisuke Maeshima, Stephanie M. Stanford, Deepa Hammaker, Cristiano Sacchetti, Li-fan Zeng, Rizi Ai, Vida Zhang, David L. Boyle, German R. Aleman Muench, Gen-Sheng Feng, John W. Whitaker, Zhong-Yin Zhang, Wei Wang, Nunzio Bottini, Gary S. Firestein

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Figure 5

SHP-2 is expressed in the rheumatoid arthritis synovium and promotes fibroblast-like synoviocyte aggressiveness through its phosphatase activity.

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SHP-2 is expressed in the rheumatoid arthritis synovium and promotes fib...
(A) IHC staining of rheumatoid arthritis (RA) synovial sections using anti–SHP-2 or control (Ctrl) IgG antibodies. Scale bars: 50 μm. Images from 2 independent experiments are shown. (B) WT (n = 10) and Ptpn11 heterozygous (Het, n = 8) mice were lethally irradiated at 10 to 13 weeks of age and administered bone marrow from WT congenic CD45.1 donor mice (12 weeks of age). After 10 weeks, arthritis was induced in recipients by i.p. injection of K/BxN sera. Mean ± SEM ankle swelling is shown. Data were analyzed using 2-way ANOVA. (C) After a 48-hour serum starvation, RA fibroblast-like synoviocytes (FLS) were allowed to migrate through Transwell chambers in response to 5% FBS for 4 hours in the presence of 25 μM 11a-1 or DMSO. Box-and-whisker plots depict median (line within box), 25th percentile and 75th percentile (bottom and top borders), and range of minimum to maximum values (whiskers) of mean cells per field from 3 independent experiments with RA FLS from different donors. Data were analyzed using the 2-tailed Mann-Whitney test. (D) After a 48-hour serum starvation, RA FLS were stimulated with 50 ng/ml TNF or 2 ng/ml IL-1β for 24 hours in the presence of 25 μM 11a-1 or DMSO. mRNA expression was analyzed for the indicated genes by qPCR performed in triplicate. Box-and-whisker plots depict mRNA expression in RA FLS from 4 different donors normalized to GAPDH expression. Data were analyzed using the 2-tailed Mann-Whitney test.