Organ Messenger Ribonucleic Acid and Plasma Proteome Changes in the Adjuvant-Induced Arthritis Model: Responses to Disease Induction and Therapy with the Estrogen Receptor-β Selective Agonist ERB-041

Two receptors [estrogen receptor (ER)α and ERβ] mediate the manifold effects of estrogens throughout the body. Although a clear role has been established for ERα in the classical effects of estrogen activity, the physiological role of ERβ is less well understood. A small-molecule ERβ selective agonist, ERB-041, has potent antiinflammatory activity in the Lewis rat model of adjuvant-induced arthritis. To characterize the response of target organs and pathways responsible for this antiinflammatory effect, mRNA expression profiling of the spleen, lymph node, and liver was performed, in conjunction with a global analysis of the plasma proteome. We find that the expression of a large number of genes and proteins are altered in the disease model and the majority of these are partially or fully reversed by ERB-041 treatment. Regulated pathways include the acute-phase response, eicosanoid synthesis, fatty acid metabolism, and iron metabolism. In addition, many of the regulated genes and proteins are known to be dysregulated in human rheumatoid arthritis, providing further evidence that the manifestations of the Lewis rat adjuvant-induced arthritis model bear similarity to the human disease.