RESUMO
Monocytes and macrophages are key mediators of inflammation in rheumatoid arthritis (RA). Their persistence at the inflammatory site is likely to contribute to immunopathology. We sought to characterise one mechanism by which persistence may be achieved: resistance to apoptosis and the role of mir-155 in this process. CD14+ monocytes from peripheral blood (PBM) and synovial fluid (SFM) of RA patients were found to be resistant to spontaneous apoptosis relative to PBM from healthy control (HC) individuals. RA SFM were also resistant to anti-Fas-mediated apoptosis and displayed a gene expression profile distinct from HC and RA PBM populations. Gene expression profiling analysis revealed that the differentially expressed genes in RA SFM vs. PBM were enriched for apoptosis-related genes and showed increased expression of the mir-155 precursor BIC. Following identification of potential mir-155 target transcripts by bioinformatic methods, we show increased levels of mature mir-155 expression in RA PBM and SFM vs. HC PBM and a corresponding decrease in SFM of two predicted mir-155-target mRNAs, apoptosis mediators CASP10 and APAF1. Using miR mimics, we demonstrate that mir-155 over-expression in healthy CD14+ cells conferred resistance to spontaneous apoptosis, but not Fas-induced death in these cells, and resulted in increased production of cytokines and chemokines. Collectively our data indicate that CD14+ cells from patients with RA show enhanced resistance to apoptosis, and suggest that an increase in mir-155 may partially contribute to this phenotype.
Assuntos
Apoptose/genética , Artrite Reumatoide/genética , Artrite Reumatoide/imunologia , MicroRNAs/genética , Monócitos/imunologia , Monócitos/metabolismo , Artrite Reumatoide/metabolismo , Biomarcadores , Estudos de Casos e Controles , Sobrevivência Celular/genética , Biologia Computacional/métodos , Citocinas/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Ontologia Genética , Humanos , Imunofenotipagem , Mediadores da Inflamação/metabolismo , Receptores de Lipopolissacarídeos/metabolismo , Fenótipo , Interferência de RNA , Receptor fas/metabolismoRESUMO
Tumor necrosis factor (TNF)-alpha inhibitors are effective biologics in the treatment of inflammatory bowel disease; however, they increase susceptibility to opportunistic infections. We report a case of a 74-year-old female with Crohn's disease who developed concomitant pulmonary tuberculosis (Mycobacterium tuberculosis [MTB]) and Histoplasmosis capsulatum infection while on adalimumab. Co-infection is rare in patients on TNF-alpha inhibitor therapy, and most cases have been reported in patients with human immunodeficiency virus (HIV). This was a challenging case for diagnosis and treatment due to indistinguishable presenting symptoms of both infections, similar laboratory and radiographical findings, and a clinical course complicated by drug-drug interactions and worsening of symptoms despite therapy.