RESUMEN
Rheumatoid arthritis (RA) is a chronic inflammatory arthritis. Currently, diagnosis of RA may take several weeks, and factors used to predict a poor prognosis are not always reliable. Gene expression in RA may consist of a unique signature. Gene expression analysis has been applied to synovial tissue to define molecularly distinct forms of RA; however, expression analysis of tissue taken from a synovial joint is invasive and clinically impractical. Recent studies have demonstrated that unique gene expression changes can be identified in peripheral blood mononuclear cells (PBMCs) from patients with cancer, multiple sclerosis, and lupus. To identify RA disease-related genes, we performed a global gene expression analysis. RNA from PBMCs of 9 RA patients and 13 normal volunteers was analyzed on an oligonucleotide array. Compared with normal PBMCs, 330 transcripts were differentially expressed in RA. The differentially regulated genes belong to diverse functional classes and include genes involved in calcium binding, chaperones, cytokines, transcription, translation, signal transduction, extracellular matrix, integral to plasma membrane, integral to intracellular membrane, mitochondrial, ribosomal, structural, enzymes, and proteases. A k-nearest neighbor analysis identified 29 transcripts that were preferentially expressed in RA. Ten genes with increased expression in RA PBMCs compared with controls mapped to a RA susceptibility locus, 6p21.3. These results suggest that analysis of RA PBMCs at the molecular level may provide a set of candidate genes that could yield an easily accessible gene signature to aid in early diagnosis and treatment.
Asunto(s)
Artritis Reumatoide/sangre , Artritis Reumatoide/genética , Cromosomas Humanos Par 6/genética , Leucocitos Mononucleares/metabolismo , Adulto , Anciano , Artritis Reumatoide/patología , Estudios de Casos y Controles , Análisis por Conglomerados , Femenino , Fluorescencia , Regulación de la Expresión Génica , Predisposición Genética a la Enfermedad , Humanos , Técnicas In Vitro , Persona de Mediana Edad , Hibridación de Ácido Nucleico , Análisis de Secuencia por Matrices de Oligonucleótidos , ARN/genética , Transcripción GenéticaRESUMEN
Tumor necrosis factor (TNF)-alpha is a well validated therapeutic target for the treatment of rheumatoid arthritis. TNF-alpha is initially synthesized as a 26-kDa membrane-bound form (pro-TNF) that is cleaved by a Zn-metalloprotease named TNF-alpha-converting enzyme (TACE) to generate the 17-kDa, soluble, mature TNF-alpha. TACE inhibitors that prevent the secretion of soluble TNF-alpha may be effective in treating rheumatoid arthritis (RA) patients. Using a structure-based design approach, we have identified a novel dual TACE/matrix metalloprotease (MMP) inhibitor 4-[[4-(2-butynyloxy)phenyl]sulfonyl]-N-hydroxy-2,2-dimethyl-(3S)thiomorpholinecarboxamide (TMI-1). This molecule inhibits TACE and several MMPs with nanomolar IC(50) values in vitro. In cell-based assays such as monocyte cell lines, human primary monocytes, and human whole blood, it inhibits lipopolysaccharide (LPS)-induced TNF-alpha secretion at submicromolar concentrations, whereas there is no effect on the TNF-alpha mRNA level as judged by RNase protection assay. The inhibition of LPS-induced TNF-alpha secretion is selective because TMI-1 has no effect on the secretion of other proinflammatory cytokines such as interleukin (IL)-1beta, IL-6, and IL-8. Importantly, TMI-1 potently inhibits TNF-alpha secretion by human synovium tissue explants of RA patients. In vivo, TMI-1 is highly effective in reducing clinical severity scores in mouse prophylactic collagen-induced arthritis (CIA) at 5, 10, and 20 mg/kg p.o. b.i.d. and therapeutic CIA model at 100 mg/kg p.o. b.i.d. In summary, TMI-1, a dual TACE/MMP inhibitor, represents a unique class of orally bioavailable small molecule TNF inhibitors that may be effective and beneficial for treating RA.