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ObjectiveEpigenetic modifications have previously been associated with rheumatoid arthritis (RA). In this study, we aimed to determine whether differential DNA methylation in peripheral blood cell subpopulations is associated with any of 4 clinical outcomes among RA patients.MethodsPeripheral blood samples were obtained from 63 patients in the University of California, San Francisco RA cohort (all satisfied the American College of Rheumatology classification criteria; 57 were seropositive for rheumatoid factor and/or anti-cyclic citrullinated protein). Fluorescence-activated cell sorting was used to separate the cells into 4 immune cell subpopulations (CD14+ monocytes, CD19+ B cells, CD4+ naive T cells, and CD4+ memory T cells) per individual, and 229 epigenome-wide DNA methylation profiles were generated using Illumina HumanMethylation450 BeadChips. Differentially methylated positions and regions associated with the Clinical Disease Activity Index score, erosive disease, RA Articular Damage score, Sharp score, medication at time of blood draw, smoking status, and disease duration were identified using robust regression models and empirical Bayes variance estimators.ResultsDifferential methylation of CpG sites associated with clinical outcomes was observed in all 4 cell types. Hypomethylated regions in the CYP2E1 and DUSP22 gene promoters were associated with active and erosive disease, respectively. Pathway analyses suggested that the biologic mechanisms underlying each clinical outcome are cell type-specific. Evidence of independent effects on DNA methylation from smoking, medication use, and disease duration were also identified.ConclusionMethylation signatures specific to RA clinical outcomes may have utility as biomarkers or predictors of exposure, disease progression, and disease severity.

Systemic sclerosis (SSc) is an autoimmune disease characterized by fibrosis of skin and internal organs. Protein tyrosine phosphatases have received little attention in the study of SSc or fibrosis. Here, we show that the tyrosine phosphatase PTP4A1 is highly expressed in fibroblasts from patients with SSc. PTP4A1 and its close homolog PTP4A2 are critical promoters of TGFβ signaling in primary dermal fibroblasts and of bleomycin-induced fibrosis in vivo. PTP4A1 promotes TGFβ signaling in human fibroblasts through enhancement of ERK activity, which stimulates SMAD3 expression and nuclear translocation. Upstream from ERK, we show that PTP4A1 directly interacts with SRC and inhibits SRC basal activation independently of its phosphatase activity. Unexpectedly, PTP4A2 minimally interacts with SRC and does not promote the SRC-ERK-SMAD3 pathway. Thus, in addition to defining PTP4A1 as a molecule of interest for TGFβ-dependent fibrosis, our study provides information regarding the functional specificity of different members of the PTP4A subclass of phosphatases.

ObjectiveWe assessed implementation of the 10-item Patient-Reported Outcomes Measurement Information System (PROMIS) physical function form (PF-10a) in routine practice in a racially and ethnically diverse population with rheumatoid arthritis (RA). Objectives were to determine feasibility of implementing PF-10a in the electronic health record (EHR) and PF-10a validity and longitudinal responsiveness.MethodsClinical and demographic data were abstracted from EHRs for all RA patients seen at a university-based rheumatology clinic between February 2013 and February 2015. We evaluated floor and ceiling (edge) effects and construct validity of PF-10a in a subgroup of patients with Health Assessment Questionnaire (HAQ) scores (n = 189). We used linear mixed-effects models to assess responsiveness of PF-10a to longitudinal changes in the Clinical Disease Activity Index (CDAI) for patients in the entire clinical cohort, with both scores recorded on at least 2 encounters (n = 326).ResultsHalf of the patients were nonwhite, and 15% were non-English speakers. Over a 2-year period, PF10a was successfully implemented; 97% of patients and 89% of encounters had at least 1 measurement performed. PF-10a had fewer ceiling (defined as best) effects than the HAQ (8% versus 22%), and convergent validity was high (r = -0.85). PF-10a was sensitive to expected differences (older versus younger patients, more versus less active disease). Longitudinal changes in PF-10a were highly associated with changes in the CDAI score (P