Folate receptor-targeted aminopterin therapy is highly effective and specific in experimental models of autoimmune uveitis and autoimmune encephalomyelitis

• Published in: Clinical immunology (Orlando, Fla.) Vol. 150; no. 1; pp. 64 - 77
• Main Authors: Lu, Yingjuan, Wollak, Kristin N, Cross, Vicky A, Westrick, Elaine, Wheeler, Leroy W, Stinnette, Torian W, Vaughn, Jeremy F, Hahn, Spencer J, Xu, Le-Cun, Vlahov, Iontcho R, Leamon, Christopher P
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.01.2014
• Subjects: Allergy and Immunology; Aminopterin; Aminopterin - pharmacology; Aminopterin - therapeutic use; Animals; Anti-Inflammatory Agents - pharmacology; Anti-Inflammatory Agents - therapeutic use; Anti-inflammatory therapy; Autoimmune encephalomyelitis; Autoimmune uveitis; Brain - drug effects; Brain - immunology; Brain - pathology; EC0746; Encephalomyelitis, Autoimmune, Experimental - drug therapy; Encephalomyelitis, Autoimmune, Experimental - immunology; Encephalomyelitis, Autoimmune, Experimental - pathology; Female; Folate receptor; Folate Receptor 2 - immunology; Folic Acid Antagonists - pharmacology; Folic Acid Antagonists - therapeutic use; Macrophages - drug effects; Macrophages - immunology; Rats; Rats, Inbred Lew; Spinal Cord - drug effects; Spinal Cord - immunology; Uveitis - drug therapy; Uveitis - immunology; Uveitis - pathology; EC0746; Folate receptor; Aminopterin; Anti-inflammatory therapy; Autoimmune encephalomyelitis; Autoimmune uveitis
• ISSN: 1521-6616; 1521-7035
• DOI: 10.1016/j.clim.2013.10.010

Abstract EC0746 is a rationally designed anti-inflammatory drug conjugate consisting of a modified folic acid-based ligand linked to a γ-hydrazide analog of aminopterin. In this report, EC0746's effectiveness was evaluated against experimental retinal S-antigen (PDSAg) induced autoimmune uveitis (EAU) and myelin-basic-protein induced autoimmune encephalomyelitis (EAE). In both models, functional FR-β was detected on activated macrophages in local (retinal or central-nervous-system, respectively) and systemic (peritoneal cavity) sites of inflammation. In myelin-rich regions of EAE rats, an increased uptake of99m Tc-EC20 (etarfolatide; a FR-specific radioimaging agent) was also observed. EC0746 treatment at disease onset suppressed the clinical severity of both EAU and EAE, and it strongly attenuated progressive histopathological changes in the affected organs. In all parameters assessed, EC0746 activity was completely blocked by a benign folate competitor, suggesting that these therapeutic outcomes were specifically FR-β mediated. EC0746 may emerge as a useful macrophage-modulating agent for treating inflammatory episodes of organ-specific autoimmunity.