AAV-mediated expression of HLA-G1/5 reduces severity of experimental autoimmune uveitis

Elizabeth Crabtree,Brian C Gilger,Jacklyn H Salmon,Matthew L Hirsch,Telmo Llanga,Megan Cullen,Liujiang Song,Jacquelyn J Bower

doi:10.1038/s41598-019-56462-3

Abstract

Non-infectious uveitis (NIU) is an intractable, recurrent, and painful disease that is a common cause of vision loss. Available treatments of NIU, such as the use of topical corticosteroids, are non-specific and have serious side effects which limits them to short-term use; however, NIU requires long-term treatment to prevent vision loss. Therefore, a single dose therapeutic that mediates long-term immunosuppression with minimal side effects is desirable. In order to develop an effective long-term therapy for NIU, an adeno-associated virus (AAV) gene therapy approach was used to exploit a natural immune tolerance mechanism induced by the human leukocyte antigen G (HLA-G). To mimic the prevention of NIU, naïve Lewis rats received a single intravitreal injection of AAV particles harboring codon-optimized cDNAs encoding HLA-G1 and HLA-G5 isoforms one week prior to the induction of experimental autoimmune uveitis (EAU). AAV-mediated expression of the HLA-G-1 and -5 transgenes in the targeted ocular tissues following a single intravitreal injection of AAV-HLA-G1/5 significantly decreased clinical and histopathological inflammation scores compared to untreated EAU eyes (p < 0.04). Thus, localized ocular gene delivery of AAV-HLA-G1/5 may reduce the off-target risks and establish a long-term immunosuppressive effect that would serve as an effective and novel therapeutic strategy for NIU, with the potential for applications to additional ocular immune-mediated diseases.

Highlights

Uveitis is an inflammation of the iris, ciliary body, and choroid associated with both infectious and non-infectious causes[1,2,3,4]
This initial study in healthy and Experimental autoimmune uveitis (EAU) rats demonstrated that intravitreal injection of AAV serotype 8 (AAV8)-GFP resulted in greater transduction of the anterior uvea compared to the same vector/dose that was administered by intracameral injection
These results demonstrated strong GFP staining in cells of the inflamed ciliary body and iris in eyes injected intravitreally with AAV8-GFP (Fig. 1)

Summary

Introduction

Uveitis is an inflammation of the iris, ciliary body, and choroid associated with both infectious and non-infectious causes[1,2,3,4]. The blood ocular barrier limits the immune response to intraocular antigens Any disruption of this barrier, either from systemic disease, trauma or inflammation, can cause this barrier to become leaky and allow blood products and inflammatory cells to enter the eye[1,7,8]. Conventional treatment of NIU is non- specific, including frequent use of topical and/or systemic corticosteroids and other immunosuppressive agents; none of which are effective in preventing uveitis relapses. As recurrent NIU necessitates long-term immunosuppression to prevent vision loss, a single dose treatment that mediates long-term immunosuppression in the target tissue without side effects is desired. We describe an endogenous human molecule capable of immune suppression at most levels that is already implicated in ocular immune privilege (HLA-G) for the treatment of NIU using AAV gene therapy. The results demonstrate that AAV-mediated expression of HLAG-1 and -5 gene therapy is an effective and novel gene therapy for the treatment of EAU

Methods

Results

Conclusion