Epigenetic basis for aberrant upregulation of autoantigen genes in humans with ANCA vasculitis
Dominic J. Ciavatta, … , J. Charles Jennette, Ronald J. Falk
Dominic J. Ciavatta, … , J. Charles Jennette, Ronald J. Falk
Published August 16, 2010
Citation Information: J Clin Invest. 2010;120(9):3209-3219. https://doi.org/10.1172/JCI40034.
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Research Article Autoimmunity

Epigenetic basis for aberrant upregulation of autoantigen genes in humans with ANCA vasculitis

Abstract

Antineutrophil cytoplasmic autoantibody (ANCA) causes vascular injury that leads to small-vessel vasculitis. Patients with ANCA aberrantly express neutrophil granule–encoding genes, including 2 that encode autoantigens: proteinase 3 (PR3) and myeloperoxidase (MPO). To uncover a potential transcriptional regulatory mechanism for PR3 and MPO disrupted in patients with ANCA vasculitis, we examined the PR3 and MPO loci in neutrophils from ANCA patients and healthy control individuals for epigenetic modifications associated with gene silencing. We found that levels of the chromatin modification H3K27me3, which is associated with gene silencing, were depleted at PR3 and MPO loci in ANCA patients compared with healthy controls. Interestingly, in both patients and controls, DNA was unmethylated at a CpG island in PR3, whereas in healthy controls, DNA was methylated at a CpG island in MPO. Consistent with decreased levels of H3K27me3, JMJD3, the demethylase specific for H3K27me3, was preferentially expressed in ANCA patients versus healthy controls. In addition, we describe a mechanism for recruiting the H3K27 methyltransferase enhancer of zeste homolog 2 (EZH2) to PR3 and MPO loci mediated by RUNX3. RUNX3 message was decreased in patients compared with healthy controls, and may also be under epigenetic control. DNA methylation was increased at the RUNX3 promoter in ANCA patients. These data indicate that epigenetic modifications associated with gene silencing are perturbed at ANCA autoantigen–encoding genes, potentially contributing to inappropriate expression of PR3 and MPO in ANCA patients.

Authors

Dominic J. Ciavatta, JiaJin Yang, Gloria A. Preston, Anshul K. Badhwar, Hong Xiao, Peter Hewins, Carla M. Nester, William F. Pendergraft III, Terry R. Magnuson, J. Charles Jennette, Ronald J. Falk

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Figure 6

RUNX3 binds PR3 and MPO genes in myeloid cell lines and in ANCA patients in remission.

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RUNX3 binds PR3 and MPO genes in myeloid cell lines and in ANCA patients...
(A) Consensus RUNX3 binding sites in PR3 intron 4 and MPO intron 7 and 3′ UTR. (B) ChIP analysis for RUNX3 binding to PR3 intron 4 and MPO intron 7 in undifferentiated or PMA-differentiated U937 cells under the indicated immunoprecipitation conditions. Normal rabbit serum was used in mock immunoprecipitation. Lanes were run on the same gel but were noncontiguous (white lines). (C–E) ChIP analysis for RUNX3 binding to MPO intron 7 and 3′ UTR (C and D) or to MPO intron 7 and PR3 intron 4 (E) in neutrophils from an active ANCA vasculitis patient (C) and from ANCA vasculitis patients in remission (D and E). Relative mRNA levels were determined by Taqman quantitative RT-PCR for MPO and PR3 from total leukocytes of ANCA vasculitis patients and calculated as fold change relative to healthy control, with exact values shown above bars. Lanes in E were run on the same gel but were noncontiguous (white line).