title: Managing macrophages in rheumatoid arthritis by reform or removal.
abstract: Macrophages play a central role in the pathogenesis of rheumatoid arthritis (RA). There is an imbalance of inflammatory and antiinflammatory macrophages in RA synovium. Although the polarization and heterogeneity of macrophages in RA have not been fully uncovered, the identity of macrophages in RA can potentially be defined by their products, including the co-stimulatory molecules, scavenger receptors, different cytokines/chemokines and receptors, and transcription factors. In the last decade, efforts to understand the polarization, apoptosis regulation, and novel signaling pathways in macrophages, as well as how distinct activated macrophages influence disease progression, have led to strategies that target macrophages with varied specificity and selectivity. Major targets that are related to macrophage development and apoptosis include TNF-α, IL-1, IL-6, GM-CSF, M-CSF, death receptor 5 (DR5), Fas, and others, as listed in Table 1. Combined data from clinical, preclinical, and animal studies of inhibitors of these targets have provided valuable insights into their roles in the disease progression and, subsequently, have led to the evolving therapeutic paradigms in RA. In this review, we propose that reestablishment of macrophage equilibrium by inhibiting the development of, and/or eliminating, the proinflammatory macrophages will be an effective therapeutic approach for RA and other autoimmune diseases.
authors.affiliation: Division of Clinical Immunology and Rheumatology, Department of Medicine, University of Alabama at Birmingham, SHEL Bldg., Suite 337, 1825 University Blvd., Birmingham, AL 35294-2182, USA. junliuab@uab.edu
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.forename: Hui-Chen
authors.initials: HC
authors.lastname: Hsu
authors.forename: John D
authors.initials: JD
authors.lastname: Mountz
mesh_terms: D000818:Animals; D018501:Antirheumatic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D001172:Arthritis, Rheumatoid / Q000188:drug therapy* / Q000276:immunology; D002986:Clinical Trials as Topic; D004195:Disease Models, Animal; D006801:Humans; D008262:Macrophage Activation / Q000187:drug effects* / Q000276:immunology; D008264:Macrophages / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D013583:Synovial Membrane / Q000187:drug effects* / Q000276:immunology; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000378:metabolism
chemical_list: D018501:Antirheumatic Agents; D053221:TNF-Related Apoptosis-Inducing Ligand