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.

TGF‐β1 alters DNA methylation levels in promoter and enhancer regions of the WT1 gene in human podocytes

“…Data on enhancers, however, yields less clear conclusions. There are reports that enhancer methylation decreases gene expression, while others have found an increase in gene expression . Our results suggest that WT1 enhancer methylation activates expression of the gene.…”

Genetic and environmental risk factors for rheumatoid arthritis

“…Specifically, methylation changes in several regions in the genome of fibroblast-like synoviocytes (FLS) from RA joints have been associated with more aggressive RA (47, 48). These methylation changes are hypothesized to alter gene expression and increase disease activity in patients with RA, although it is not yet clear when in the course of disease these changes occur, and it may be that they are late changes and unrelated to disease initiation.…”

Targeting Tyrosine Phosphatases: Time to End the Stigma

“…The SHP-2 inhibitor 11a-1 resulted from an attempt to generate bidentate SHP-2 inhibitors, and was recently employed to demonstrate that SHP-2 –a known target for cancer–is also a promising target for rheumatoid arthritis[25]. A precursor inhibitor, II-B08, was generated from screening a combinatorial library containing a pTyr mimetic salicylic acid core for binding the PTP active-site and a structurally diverse set of amines and hydrazines for additional interactions[26].…”

“…We demonstrated that SHP-2 expression is increased in fibroblast-like synoviocytes (FLS) –joint-lining cells that become invasive and contribute to joint destruction during rheumatoid arthritis (RA)- from RA patients, and that SHP-2 promotes platelet-derived growth factor and tumor necrosis factor (TNF) signaling in these cells[29]. Heterozygous deletion of SHP-2 in radioresistant cells (which include FLS) or acute heterozygous deletion in myeloid cells significantly reduced arthritis development in the K/BxN serum transfer mouse model, which is dependent on actions of FLS and myeloid cells[25]. 11a-1 treatment reduced RA FLS migration and expression of mediators of invasiveness in response to TNF and interleukin (IL)-1, and daily administration substantially decreased K/BxN arthritis[25].…”

“…Heterozygous deletion of SHP-2 in radioresistant cells (which include FLS) or acute heterozygous deletion in myeloid cells significantly reduced arthritis development in the K/BxN serum transfer mouse model, which is dependent on actions of FLS and myeloid cells[25]. 11a-1 treatment reduced RA FLS migration and expression of mediators of invasiveness in response to TNF and interleukin (IL)-1, and daily administration substantially decreased K/BxN arthritis[25]. …”