Development of novel immune mechanism-based therapies for autoimmune uveitis using a mouse model of experimental autoimmune uveitis

Abstract

The purpose of this study is to ameliorate experimental autoimmune uveitis (EAU) in mice as an animal model with tolerogenic antigen presenting cells (TolAPC) or other drugs including proteasome inhibitor bortezomib and N-acetylcysteine and then to investigate the mechanisms Uveitis refers to inflammation of the uveal tissues and can cause significant ocular morbidities in individuals with protracted diseases Clinical courses refractory to conventional treatment with corticosteroids are not uncommon and the adverse effects associated with steroids such as cataracts and glaucoma preclude its chronic use Therefore investigating the disease mechanisms and searching for alternative treatments for uveitis remain important issues Experimental autoimmune uveitis (EAU) is a rodent model of human uveoretinitis Here we want to treat experimental autoimmune uveitis (EAU) in mice as an animal model with different novel immune mechanism-based strategies In the first part it is well known that inoculation of antigen into the anterior chamber (a c ) of a mouse eye induces Anterior Chamber Associated Immune Deviation (ACAID) which in part is mediated by antigen specific local and peripheral tolerance to the inciting antigen ACAID can also be induced in vivo by inoculation ( i v ) of ex-vivo generated tolerogenic antigen presenting cells (TolAPC) Therefore we plan to test if ex-vivo generated retinal antigen pulsed TolAPC could suppress established experimental autoimmune uveitis (EAU) or not In the second part bortezomib is a proteasome inhibitor used for hematologic cancer treatment Since it can suppress NF-κB activation which is critical for the inflammatory process bortezomib has been found to possess anti-inflammatory activity Therefore we evaluated the effect of bortezomib on experimental autoimmune uveitis (EAU) in mice and investigated the potential mechanisms related to NF-κB inactivation In the third part The Ncf1 protein is an essential component of the NADPH oxidase complex that catalyzes the transfer of a single electron from NADPH to oxygen and generates reactive oxygen species (ROS) The mutation of Ncf1 gene is related to chronic granulomatous disease (CGD) a rare genetic disorder characterized by severe recurrent infections due to the inability of neutrophils and macrophages to mount a respiratory burst and thereby kill the invading pathogens However enhanced autoimmunity arthritis and encephalomyelitis in mice with a reduced oxidative burst due to a mutation in the Ncf1 gene were reported Therefore we postulate that Ncf1 gene also plays an important role in experimental autoimmune uveitis in mice As the result first of all we established an experimental autoimmune uveitis (EAU) mouse model to address the mechanisms and potential methods of treatment for ocular autoimmune diseases in this study Then in the first part I found that IRBP1-20-pulsed TolAPC suppressed the incidence and severity of the clinical expression of EAU and reduced the expression of associated inflammatory mediators Moreover extract of whole retina could replace human IRBP1-20 as antigen in the preparation of TolAPC used to induce tolerance in EAU mice The suppression of EAU could be transferred to a new set of EAU mice with CD8+ but not with CD4+ Treg cells In the second part we found that the EAU is ameliorated by high-dose bortezomib treatment when compared with low-dose bortezomib or PBS treatment The DNA-binding activity of NF-κB was suppressed and expression of several key inflammatory mediators including TNF-? IL-1? IL-1β IL-12 IL-17 MCP-1 and iNOS were lowered in the high-dose bortezomib treated group In the third part we found that the EAU response became much milder in Ncf1-mutant mice Adoptive transfer of CD4+ T cells from wild-type EAU mice induced partial EAU response in Ncf1 mutant na?ve mice Adoptively transfer of CD4+ T cells from Ncf1 mutant EAU mice also induced partial EAU response in na?ve B6 mice It meant that the Ncf1 gene expression in both donor CD4+ T cells and recipient B6 mice contributed to EAU induction Finally we treated the EAU B6 mice with N-acetylcysteine (NAC) i p every other day to suppress the ROS production as in Ncf1-mutant mice We found the EAU response was ameliorated in NAC treated mice as in Ncf1-mutant EAU mice Therefore NAC treatment with ameliorated ROS production seems to be a novel immune mechanism-based therapy for autoimmune uveitis In conclusion we find many potential novel immune mechanism-based treatment strategies for human uveoretinitis including tolerogenic antigen presenting cells (TolAPC) with retinal extract as antigen proteasome inhibitor bortezomib with NF-κB inactivation and N-acetylcysteine (NAC) for ROS suppression as in Ncf1 mutant mice We hope these novel immune mechanism-based therapies could be applied for autoimmune uveitis treatment in human in the future

Date of Award	2014 Aug 29
Original language	English
Supervisor	Chi-Chang Shieh (Supervisor)