AAV2-mediated subretinal gene transfer of hIFN-α attenuates experimental autoimmune uveoretinitis in mice

Single‐cell RNA sequencing reveals inflammatory retinal microglia in experimental autoimmune uveitis

Autoimmune uveitis (AU) is a kind of immune-mediated disease resulting in irreversible ocular damage and even permanent vision loss. However, the precise mechanism underlying dynamic immune changes contributing to disease initiation and progression of AU remains unclear. Here, we induced an experimental AU (EAU) model with IRBP651-670 and found that day[D]14 was the inflammatory summit with remarking clinical and histopathological manifestations and the activation of retinal microglia exhibited a time-dependent pattern in the EAU course. We conducted single-cell RNA sequencing of retinal immune cells in EAU mice at four time points and found microglia constituting the largest proportion, especially on D14. A novel inflammatory subtype (Cd74high Ccl5high) of retinal microglia was identified at the disease peak that was closely associated with modulating immune responses. In vitro experiments indicated that inflammatory stimuli induced proinflammatory microglia with the upregulation of CD74 and CCL5, and CD74 overexpression in microglia elicited their proinflammatory phenotype via nuclear factor-kappa B signaling that could be attenuated by the treatment of neutralizing CCL5 antibody to a certain extent. In-vivo blockade of Cd74 and Ccl5 effectively alleviated retinal microglial activation and disease phenotype of EAU. Therefore, we propose targeting CD74 and CCL5 of retinal microglia as promising strategies for AU treatment.

Global lactylome reveals lactylation-dependent mechanisms underlying TH17 differentiation in experimental autoimmune uveitis

Dysregulation of CD4+ T cell differentiation is linked to autoimmune diseases. Metabolic reprogramming from oxidative phosphorylation to glycolysis and accumulation of lactate are involved in this process. However, the underlying mechanisms remain unclear. Our study showed that lactate-derived lactylation regulated CD4+ T cell differentiation. Lactylation levels in CD4+ T cells increased with the progression of experimental autoimmune uveitis (EAU). Inhibition of lactylation suppressed TH17 differentiation and attenuated EAU inflammation. The global lactylome revealed the landscape of lactylated sites and proteins in the CD4+ T cells of normal and EAU mice. Specifically, hyperlactylation of Ikzf1 at Lys164 promoted TH17 differentiation by directly modulating the expression of TH17-related genes, including Runx1, Tlr4, interleukin-2 (IL-2), and IL-4. Delactylation of Ikzf1 at Lys164 impaired TH17 differentiation. These findings exemplify how glycolysis regulates the site specificity of protein lactylation to promote TH17 differentiation and implicate Ikzf1 lactylation as a potential therapeutic target for autoimmune diseases.

Apigenin Alleviates Autoimmune Uveitis by Inhibiting Microglia M1 Pro-Inflammatory Polarization

Purpose

Apigenin is a natural small molecule compound widely present in various vegetables and fruits. Recently, Apigenin was reported to inhibit lipopolysaccharide (LPS)-simulated microglial proinflammatory activation. Considering the important role of microglia in retinal disorders, we wonder whether Apigenin could exert a therapeutic effect on experimental autoimmune uveitis (EAU) through reprogramming retinal microglia to a beneficial subtype.

Methods

EAU was induced in C57BL/6J mice by immunization with interphotoreceptor retinoid-binding protein (IRBP)651-670, followed by intraperitoneal administration of Apigenin. Disease severity was assessed based on clinical and pathological scores. In vivo, Western blotting was used to quantify protein levels of classical inflammatory factors, microglial M1/M2 markers and the tight junction protein of the blood-retinal-barrier (BRB). Immunofluorescence was used to determine the Apigenin's efficacy on microglial phenotype. In vitro, Apigenin was added in LPS and IFN-γ stimulated human microglial cell line. Western blotting and Transwell assays were used to analyze the phenotype of microglia.

Results

In vivo, we found that Apigenin significantly reduced the clinical and pathological scores of EAU. The protein levels of inflammatory cytokines were significantly decreased in retina, and BRB disruption was ameliorated after Apigenin treatment. Meanwhile, Apigenin inhibited microglia M1 transition in EAU mice retina. In vitro functional studies showed that Apigenin decreased LPS and IFN-γ-induced microglial inflammatory factor production and M1-activation via the TLR4/MyD88 pathway.

Conclusions

Apigenin can ameliorate retinal inflammation in IRBP induced autoimmune uveitis through inhibiting microglia M1 pro-inflammatory polarization via TLR4/MyD88 pathway.

Galectin-3 regulates microglial activation and promotes inflammation through TLR4/MyD88/NF-kB in experimental autoimmune uveitis

Galectin-3, an attractive molecule of innate immunity, has been reported to be involved in the neuroinflammatory diseases. However, the role of Galectin-3 in autoimmune uveitis is still unclear. The purpose of this study was to investigate the effect and mechanism of Galectin-3 on microglial activation and inflammation of experimental autoimmune uveitis (EAU)_. We immunized female C57BL/6 J mice with IRBP_651-670 to induce EAU and the specific inhibitor was intravitreally injected in EAU mice. Disease severity was evaluated by clinical and histopathological scores. Immunofluorescence, western blot, qRT-PCR analysis and immunoprecipitation were used to detect the functional phenotypes and mechanisms on microglia after Galectin-3 inhibition. Our results showed that the expression of Galectin-3 was conspicuously increased in microglia of EAU retinas. The specific inhibitor of Galectin-3, TD139 was found to ameliorate the clinical and histological manifestations of EAU mice. In addition, TD139 reduced the expression of proinflammatory factors in vivo and vitro, which are related to the severity of uveitis. In mechanism, TD139 down-regulated the expression of TLR4 and MyD88, and then inhibited the activation of NF-κB p65 in microglia. In conclusion, Galectin-3 may play important roles in a variety of immune related diseases including autoimmune uveitis. Additionally, the inhibition of Galectin-3 may attenuate the microglial activation and inflammatory response through TLR4/MyD88/NF-κB pathway, highlighting a potential therapeutic target of Galectin-3 for autoimmune uveitis.

Beneficial effect of dimethyl fumarate on experimental autoimmune uveitis is dependent of pro-inflammatory markers immunomodulation

Autoimmune uveitis is an inflammatory disease of the eye and is one of the major causes of blindness worldwide. Experimental autoimmune uveoretinitis (EAU) constitutes an animal disease model of human endogenous uveitis. In our study, we investigated the immunomodulatory effect of dimethyl fumarate (DMF) using bovine retinal extract-induced uveitis in a Female Wistar rats. To evaluate the in vivo efficacy, Female Wistar rats were divided into seven experimental groups: control group (n = 5), consisting of non-immunized animals; Uveoretinitis (n = 5), and DMF/Uveoretinitis groups (n = 15), which received a subcutaneous injection of bovine retinal extract emulsified in complete Freund's adjuvant; MC group (n = 5), treated by daily intragastric administration of methylcellulose 0.08% in tap water; DMF group, consisting of control positive group, rats received daily oral gavage administration of 500 μL of dimethyl fumarate at 100 mg/Kg dissolved in 0.08% methylcellulose in tap water (n = 5). On day 14 post immunization, the rats were then euthanized and associated indications were investigated to evaluate the therapeutic efficacy. Nitric oxide (NO) and TNF-α were assessed in plasma. Meanwhile, eyes were collected for histological and immunohistochemical studies. The retinal expression of iNOS, CD68, CD20, CD25, CD4, and CD8 was examined. Interestingly, DMF enhanced a significant reduction of NO and TNF-α production in the treated group. This effect was strongly related to the histological structure of eyes improvement. In the same context, a significant decrease of iNOS, CD68, and CD20 expression and CD25 increase expression were reported in retinal tissue of DMF/Uveoretinitis group in comparison to the immunized group. Collectively, our results indicate that DMF treatment has a beneficial effect in experimental autoimmune uveoretinitis and could constitute a good candidate for monitoring an ocular inflammatory diseases.

Small molecules targeting RORγt inhibit autoimmune disease by suppressing Th17 cell differentiation

Th17 cells, a lymphocyte subpopulation that is characterized by the expression of the transcription factor "retinoic acid receptor-related orphan receptor gamma-t" (RORγt), plays an important role in the pathogenesis of autoimmune disease. The current study was set up to discover novel and non-steroidal small-molecule inverse agonists of RORγt and to determine their effects on autoimmune disease. Structure-based virtual screening (SBVS) was used to find compounds targeting RORγt. Flow cytometry was used to detect the Th17 cell differentiation. Inverse agonists were intraperitoneally administered to mice undergoing experimental autoimmune uveitis (EAU), experimental autoimmune encephalomyelitis (EAE) or type 1 diabetes. The effects of the inverse agonists were evaluated by clinical or histopathological scoring. Among 1.3 million compounds screened, CQMU151 and CQMU152 were found to inhibit Th17 cell differentiation without affecting the differentiation of Th1 and Treg lineages (both P = 0.001). These compounds also reduced the severity of EAU (P = 0.01 and 0.013) and functional studies showed that they reduced the number of Th17 cell and the expression of IL-17(Th17), but not IFN-γ(Th1) and TGF-β(Treg) in mouse retinas. Further studies showed that these compounds may reduce the expression of p-STAT3 by reducing the positive feedback loop of IL-17/IL-6/STAT3. These compounds also reduced the impaired blood-retinal barrier function by upregulating the expression of tight junction proteins. These compounds were also found to reduce the severity of EAE and type 1 diabetes. Our results showed that RORγt inverse agonists may inhibit the development of autoimmune diseases and may provide new clues for the treatment of Th17-mediated immune diseases.

A cell-permeable peptide inhibitor of p55PIK signaling alleviates ocular inflammation in mouse models of uveitis

PURPOSE

Previously we developed TAT-N24 as a synthetic cell-permeable peptide inhibitor of p55PIK signaling and demonstrated its anti-inflammatory effects. This study aimed to evaluate the potential of TAT-N24 as a new agent for the treatment of ocular inflammatory diseases.

METHODS

The endotoxin-induced uveitis (EIU) model was established by intravitreal injection of lipopolysaccharide (LPS) in BALB/c mice and experimental autoimmune uveitis (EAU) model was established by subcutaneous injection of a peptide spanning amino acid residues 161-180 of interphotoreceptor retinoid binding protein (IRBP161-180) with complete Freund's adjuvant (CFA) in B10.RIII mice. TAT-N24 was topically administered in EIU model and intraperitoneally administered in EAU model. The severity levels of uveitis were assessed by clinical and histopathological scores. The mRNA levels of inflammatory cytokines in iris-ciliary body (ICB) and retina were analyzed by reverse transcription quantitative polymerase chain reaction (RT-qPCR). The protein levels of inflammatory factors were determined by ELISA or Western blotting.

RESULTS

The results showed that TAT-N24 alleviated clinical signs, decreased inflammatory cell infiltration and the expression of inflammatory cytokines in both EIU and EAU models. Furthermore, protein levels of tumor necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) in aqueous humor and mRNA and protein levels of NF-κB p65 in the ICB significantly decreased in EIU model. In EAU model, TAT-N24 application induced a significant decrease of IFN-gamma (IFN-γ) and interleukin-17 (IL-17) in the retina, which were secreted by Th1 and Th17 cells, respectively.

CONCLUSION

In conclusion, TAT-N24 suppressed intraocular inflammation in both EIU and EAU models, and the anti-inflammatory effects were mediated by suppressing the expression of inflammatory cytokines by PI3K/NF-κB signaling pathway. TAT-N24 could be potential candidate for the treatment of ocular inflammatory diseases.

Anti-CD40 monoclonal antibody ameliorates experimental autoimmune uveoretinitis in mice

OBJECTIVE

To investigate the effects of CD40 on ocular inflammation in experimental autoimmune uveoretinitis (EAU) in B10.RIII mice.

ANIMALS STUDIED

EAU-susceptible B10.RIII mice were subcutaneously immunized with interphotoreceptor retinoid-binding protein (IRBP) 161-180 in complete Freund's adjuvant and evaluated clinically and pathologically on days 7, 14, 21, 28, and 35 postimmunization. Anti-CD40 antibody was intraperitoneally injected into mice every other day from days 7 to 14 postimmunization. Phosphate-buffered saline (PBS)-injected EAU mice were used as the controls.

PROCEDURES

The frequencies of CD11c⁺ CD40⁺ dendritic cells (DCs), CD11c⁺ MHC-II⁺ DCs, and CD11c⁺ CD40⁺ MHC-II⁺ DCs in splenocytes were evaluated by flow cytometry on days 0, 7, 14, and 21 after immunization. Tumor necrosis factor (TNF)-α and interleukin (IL)-6 production in CD11c⁺ DCs was assessed by ELISA. IRBP-specific lymphocyte proliferation was assessed using a modified MTT cell proliferation assay.

RESULTS

The number of CD11c⁺ CD40⁺ DCs, CD11c⁺ MHC-II⁺ DCs, and CD11c⁺ CD40⁺ MHC-II⁺ DCs increased at the onset of EAU, peaked at the height of disease severity, and was sustained at a high level until day 21. Treatment with anti-CD40 antibody significantly alleviated clinical and pathological activities related to EAU. Compared with the control mice, antibody-treated EAU mice showed few CD11c⁺ CD40⁺ DC and CD11c⁺ CD40⁺ MHC-II⁺ DC frequencies in splenocytes. The anti-CD40 antibody significantly suppressed IRBP-specific lymphocyte proliferation and TNF-α and IL-6 production by DCs in EAU mice.

CONCLUSIONS

The increased expression of CD40 and major histocompatibility complex (MHC) class II molecules in the splenocytes of EAU mice were correlated with inflammatory activity. Anti-CD40 treatment can significantly attenuate EAU activity by inhibiting systemic IRBP-specific immune responses.

Recent advances in the management of non-infectious posterior uveitis

PURPOSE

To review the current regimens and novel therapeutic modalities in various stages of research and development for the management of non-infectious posterior uveitis (NIPU).

METHODS

We performed a thorough review of current literature using PubMed, Google Scholar and Clinicaltrials.gov to identify the published literature about the available therapeutics and novel drugs/therapies in different stages of clinical trials.

RESULTS

The current management regimen for non-infectious posterior uveitis includes corticosteroids, immunomodulatory therapies and anti-metabolites. However, NIPU requires long-term management for efficacious remission of the disease and to prevent disease relapse. Long-term safety issues associated with steroids have led to efforts to develop novel therapeutic agents including biological response modulators and immunosuppressants. The current therapeutic agents in various stages of development include calcineurin inhibitors, biologic response modifiers and a more a comprehensive modalities like ocular gene therapy as well as novel drug delivery mechanisms for higher bioavailability to the target tissues, with minimal systemic effects.

CONCLUSION

Novel efficacious therapeutic modalities under development will help overcome the challenges associated with the traditional therapeutic agents.

Analysis of the role of palmitoleic acid in acute anterior uveitis

PURPOSE

To study the role of palmitoleic acid (PA) in the pathogenesis of acute anterior uveitis (AAU).

METHODS

PA levels in feces from AAU patients were measured by gas chromatography coupled with a mass spectrometer (GC-MS) and compared with samples obtained from healthy individuals. Enzyme linked immunosorbent assay (ELISA) and flow cytometry (FCM) were used to assess the effect of PA on dendritic cells (DCs) and CD4⁺T cells obtained from mice, AAU patients and healthy individuals. C57BL/6 mice were fed with PA or vehicle and experimental autoimmune uveitis (EAU) was induced with a human retinal IRBP651-670 peptide. Disease severity of EAU was evaluated by clinical manifestation and histology. Differentiation of splenic Type 1 helper T cells (Th1) and Th17 cells was evaluated by FCM. Tandem mass tag (TMT)-based proteomics analysis was used to identify differentially expressed proteins following incubation of DCs with PA.

RESULTS

The fecal concentration of PA was increased in AAU patients as compared with healthy individuals. In vitro, PA promoted apoptosis of DCs and inhibited the secretion of TNF-α from mouse bone-marrow-derived dendritic cells (BMDCs) as well as in DCs from AAU patients and healthy individuals. It only decreased DCs surface marker expression and IL-12p70 secretion in BMDCs and healthy individuals DCs but not in AAU patient DCs. PA-treated BMDCs inhibited Th cell differentiation from mouse naïve CD4⁺T cells and IL-17 and IFN-γ secretion in co-culture supernatants. PA also inhibited the differentiation of Th cells and secretion of IFN-γ and IL-17 in CD4⁺T cells from mice, AAU patients and healthy individuals. In vivo, PA-treated EAU mice showed milder clinical and histopathological intraocular manifestations as compared with the control group. PA feeding inhibited differentiation of splenic Th17 cells, whereas Th1 cells were not affected. Up to 30 upregulated and 77 downregulated proteins were identified when comparing PA-treated DCs with controls.

CONCLUSION

An increased expression of fecal PA was observed in AAU patients. PA was shown to have immunoregulatory effects on DCs and CD4⁺T cells and attenuated disease severity in EAU mice.

Activation of the interleukin-23/interleukin-17 signalling pathway in autoinflammatory and autoimmune uveitis

Uveitis is a group of diseases characterized by intraocular inflammation, of which some are driven by autoinflammatory or autoimmune responses, such as Vogt-Koyanagi-Harada disease, Behçet's disease, uveitis associated with spondyloarthritis, ocular sarcoidosis, sympathetic ophthalmia and birdshot chorioretinopathy. These entities have various clinical forms, but genetic and biomarker data suggest that they share a common molecular basis, activation of the Interleukin (IL)-23/IL-17 pathway. Multiple factors including genetic predisposition, various cytokine imbalances, infectious agents and gut alterations are found to trigger an aberrant response of this pathway. The enhanced activity of the IL-23/IL-17 pathway is committed to the expansion and pathogenicity of Th17 cells. Evidence from animal models demonstrates that the development of pathogenic Th17 cells is responsible for the induction of experimental autoimmune uveitis. Further findings indicate that retinal pigment epithelium (RPE) cells may be a target of IL-17. IL-17 triggers downstream inflammatory cascades and causes dysfunction of RPE cells, which may affect retinal barrier function and thereby promote intraocular inflammation. Currently, several emerging drugs blocking the IL-23/IL-17 pathway have been assessed for the treatment of uveitis in pilot studies. The purpose of this is to summarize updated biological knowledge and preliminary clinical data, providing the rationale for further development and evaluation of novel drugs targeting the IL-23/IL-17 pathway in autoinflammatory and autoimmune uveitis. Future studies may focus on translational medicine targeting the IL-23/IL-17 pathway for the improvement of diagnosis and treatment of uveitis. In conclusion, activation of the IL-23/IL-17 pathway is a critical biological event and can be an important target for the treatment of autoinflammatory and autoimmune uveitis.

Effect of berberine on spleen transcriptome and gut microbiota composition in experimental autoimmune uveitis

BACKGROUND

Berberine (BBR) was reported to have immunoregulatory and anti-inflammatory properties. In this study, we investigated whether BBR could exert its effects on the development of experimental autoimmune uveitis (EAU), and if so, what was the underlying mechanism?

METHODS

EAU was induced in B10R.III mice by immunization with IRBP 161-180, followed by 100 mg/kg/d BBR intragastric administration. Disease severity was assessed by evaluation of clinical and histopathological scores. Blood-retinal barrier (BRB) breakdown was tested by Evans blue. Effector and regulatory T (Treg) cell balance was evaluated by quantitative real-time PCR and flow cytometry. Spleen transcriptome was characterized by RNA sequencing (RNA-seq). Gut microbiota composition was investigated by 16S rRNA analysis.

RESULTS

BBR treatment significantly blocked EAU as shown by the decrease of the clinical and histological scores, as well as the inhibition of BRB breakdown. The frequency of splenic Th1 and Th17 cells was decreased, whereas Treg cells were increased in the BBR-treated group. RNA-seq of the spleen revealed 476 differentially expressed genes (DEGs) between the EAU and EAU-BBR group. GO functional classification, as well as KEGG analysis demonstrated that BBR treatment markedly influences genes belonging to chromatin remodeling and immune-related pathways. Intervention with BBR modified the gut microbiome in EAU mice, increasing the number of bacteria with immunomodulatory capacity. Depletion of gut microbiota affected the efficacy of BBR on EAU. Moreover, the altered bacterial strains showed a significant correlation with the expression of histones.

CONCLUSIONS

BBR inhibited IRBP induced EAU, which was associated with a significant change in the spleen transcriptome and intestinal microbial composition.

Aerosol Inhalation-mediated Delivery of an Adeno-associated Virus 5-expressed Antagonistic Interleukin-4 Mutant Ameliorates Experimental Murine Asthma

BACKGROUND

T helper 2 (Th2) lymphocytes and associated interleukin (IL) 4 and IL-13 play crucial roles in asthma pathogenesis. In this study, we explored an adeno-associated virus 5 (AAV5) based gene therapy by delivering truncated IL-4 protein to antagonize IL-4 receptor α chain and interrupt asthmatic signal pathway.

RESULTS

A recombinant adeno-associated virus 5 (AAV5) vector harboring a truncated mouse IL-4 gene (AAV5-mIL-4ΔC22) was prepared. Western blotting showed that the IL-4 mutant protein lacking the C-terminal 22 amino acids was expressed well in AAV5-mIL-4ΔC22 infected 16HBE and BEAS-2B cells. AAV5-drivn green fluorescent protein (AAV5-GFP) served as a control. The biodistribution of vector DNA after AAV5 vector aerosol inhalation was examined by PCR and the result showed that foreign DNA was detectable in the lungs but not in other organs including gonads. The aerosol inhalation-mediated delivery of AAV5-expressed antagonistic IL-4 mutant protein improved the lung function of ovalbumin-induced asthma mice.

CONCLUSIONS

The inhalation of aerosolized AAV5-mIL-4ΔC22 significantly improved the lung function and modulated the immune cell infiltration and associated cytokine expression in the bronchoalveolar lavage fluid (BALF) of ovalbumin-induced asthma mice.

The Role of IFN-alpha in Experimental and Clinical Uveitis

PURPOSE

IFN-α is the only treatment capable of inducing long-term remission in some patients with ocular Behçet's disease. In this review, we focus on immune mechanisms of IFN-α in animal models and patients and compare the outcome of different clinical studies.

METHODS

Review of literature using PubMed and Google and original data from rat models with monophasic/chronic or relapsing experimental autoimmune uveitis treated with IFN-α.

RESULTS

The role of IFN-α and its effect on various cell types were investigated, in some cases with contradictory results. Some patients respond very well to IFN-α treatment, while others are non-responders, which was reflected in the uveitis rat models: relapsing uveitis was ameliorated, the monophasic/chronic disease even aggravated.

CONCLUSIONS

Despite intensive investigations in patients and animal models, the immune mechanisms explaining the therapeutic effect of IFN-α in ocular Behçet's disease are not yet fully understood and need further investigation.

Novel CD28 antagonist mPEG PV1-Fab' mitigates experimental autoimmune uveitis by suppressing CD4+ T lymphocyte activation and IFN-γ production

Autoimmune Uveitis is an important chronic inflammatory disease and a leading cause of impaired vision and blindness. This ocular autoimmune disorder is mainly mediated by T CD4⁺ lymphocytes poising a T_H1 phenotype. Costimulatory molecules are known to play an important role on T cell activation and therefore represent interesting therapeutical targets for autoimmune disorders. CD28 is the prototypical costimulatory molecule for T lymphocytes, and plays a crucial role in the initiation, and maintenance of immune responses. However, previous attempts to use this molecule in clinical practice achieved no success. Thus, we evaluated the efficacy of mPEG PV1-Fab’ (PV1), a novel selective CD28 antagonist monovalent Fab fragment in the treatment of Experimental Autoimmune Uveitis (EAU). Here, we showed that PV1 treatment decreases both average disease score and incidence of EAU. A decrease in the activation profile of both T CD4⁺ and T CD8⁺ eye-infiltrating lymphocytes was evidenced. In the periphery, T CD4⁺ cells from PV1-treated mice also showed a decrease in their activation status, with reduced expression of CD69, CD25, and PD-1 molecules. This suppression was not dependent on Treg cells, as both their frequency and absolute number were lower in PV1-treated mice. In addition, frequency of CD4⁺IFN-γ⁺ T cells was significantly lower in PV1-treated group, but not of IL-17-producing T cells. Moreover, after specific restimulation, PV1 blockade selectively blocked IFN-γ production by CD4⁺ lymphocytes Taken together, our data suggest that mPEG PV1-Fab’ acts mainly on IFN-γ-producing CD4⁺ T cells and emphasize that this specific CD28 blockade strategy is a potential specific and alternative tool for the treatment of autoimmune disorders in the eye.

Pharmacotherapy for uveitis: current management and emerging therapy

Uveitis, a group of conditions characterized by intraocular inflammation, is a major cause of sight loss in the working population. Most uveitis seen in Western countries is noninfectious and appears to be autoimmune or autoinflammatory in nature, requiring treatment with immunosuppressive and/or anti-inflammatory drugs. In this educational review, we outline the ideal characteristics of drugs for uveitis and review the data to support the use of current and emerging therapies in this context. It is crucial that we continue to develop new therapies for use in uveitis that aim to suppress disease activity, prevent accumulation of damage, and preserve visual function for patients with the minimum possible side effects.

A comprehensive review and update on the biologic treatment of adult noninfectious uveitis: part II

INTRODUCTION

Treatment of adult, noninfectious uveitis remains a major challenge for ophthalmologists around the world, especially in regard to recalcitrant cases. It is reported to comprise approximately 10% of preventable blindness in the USA. The cause of uveitis can be idiopathic or associated with infectious and systemic disorders. The era of biologic medical therapies provides new options for patients with otherwise treatment-resistant inflammatory eye disease.

AREAS COVERED

This two-part review gives a comprehensive overview of the existing medical treatment options for patients with adult, noninfectious uveitis, as well as important advances for the treatment ocular inflammation. Part I covers classic immunomodulation and latest information on corticosteroid therapy. In part II, emerging therapies are discussed, including biologic response modifiers, experimental treatments and ongoing clinical studies for uveitis.

EXPERT OPINION

The hazard of chronic corticosteroid use in the treatment of adult, noninfectious uveitis is well documented. Corticosteroid-sparing therapies, which offer a very favorable risk-benefit profile when administered properly, should be substituted. Although nothing is currently approved for on-label use in this indication, many therapies, through either translation or novel basic science research, have the potential to fill the currently exposed gaps.

Short hairpin RNA-mediated knockdown of VEGFA in Müller cells reduces intravitreal neovascularization in a rat model of retinopathy of prematurity

Vascular endothelial growth factor (VEGF) A is implicated in aberrant angiogenesis and intravitreous neovascularization (IVNV) in retinopathy of prematurity (ROP). However, VEGFA also regulates retinal vascular development and functions as a retinal neural survival factor. By using a relevant ROP model, the 50/10 oxygen-induced retinopathy (OIR) model, we previously found that broad inhibition of VEGFA bioactivity using a neutralizing antibody to rat VEGF significantly reduced IVNV area compared with control IgG but also significantly reduced body weight gain in the pups, suggesting an adverse effect. Therefore, we propose that knockdown of up-regulated VEGFA in cells that overexpress it under pathological conditions would reduce IVNV without affecting physiological retinal vascular development or overall pup growth. Herein, we determined first that the VEGFA mRNA signal was located within the inner nuclear layer corresponding to CRALBP-labeled Müller cells of pups in the 50/10 OIR model. We then developed a lentiviral-delivered miR-30eembedded shRNA against VEGFA that targeted Müller cells. Reduction of VEGFA by lentivector VEGFA-shRNAetargeting Müller cells efficiently reduced 50/10 OIR up-regulated VEGFA and IVNV in the model, without adversely affecting physiological retinal vascular development or pup weight gain. Knockdown of VEGFA in rat Müller cells by lentivector VEGFA-shRNA significantly reduced VEGFR2 phosphorylation in retinal vascular endothelial cells. Our results suggest that targeted knockdown of overexpressed VEGFA in Müller cells safely reduces IVNV in a relevant ROP model.

New options for uveitis treatment

Uveitis is one of the most important causes of blindness worldwide. Its etiology and pathogenesis are complicated and have not been well understood. The treatment for uveitis is predominantly based on steroids and immunosuppressants. However, systemic side effects limit their clinical application. With the advancement of molecular biology, some intravitreal implants and biologic agents have been used for the treatment of uveitis. Additionally, novel techniques such as gene therapy and RNA interference are being studied for using as uveitis therapy. This paper reviews recent advances in uveitis treatment.

Genetic variants in the JAK1 gene confer higher risk of Behcet's disease with ocular involvement in Han Chinese

Recent surveys have identified SLC22A4, SLC22A5, RUNX1, JAK1 as susceptibility genes for various immune-related diseases. An association study was performed in 738 Behcet's patients with ocular involvement and 1,873 controls using the iPLEX system method. The first-stage study for 30 SNPs showed that SNPs rs2780815, rs310241, rs3790532 in JAK1 were associated with Behcet's disease in Han Chinese (Pc(Bonferroni correction) = 0.022-7.7 × 10(-3)). The G allele and AA genotype of SNP rs2834643 in RUNX1 (Pc = 0.041-1.75 × 10(-3)), but none of the other SNPs, were associated with Behcet's disease. Haplotype analysis for the SLC22A4, SLC22A5 genes showed an increased tendency for AGTCTGCCGC frequency in patients compared with controls; however, the significance was lost after Bonferroni correction (P = 0.004, Pc > 0.05). Subsequently, we further replicated the significantly associated SNPs using another independent cohort. Replication and combining studies showed that three SNPs rs2780815, rs310241, rs3790532 in JAK1, but not SNP rs2834643 in RUNX1, were consistently associated with Behcet's disease (replication: Pc = 0.012-9.60 × 10(-4); combining: Pc = 0.030-1.90 × 10(-4)). SNPs rs2780815, rs310241, rs3790532 were estimated to confer a population attributable risk of 35.0, 28.0, 27.0 %, respectively. We found a strong association between HLA-B51 with Behcet's disease in Chinese Han population (P = 1.35 × 10(-73); OR = 5.15; 95 % CI 4.28-6.19). GMDR analysis showed that no gene-gene interaction was detectable between JAK1 and HLA-B51. Logistic analysis indicated that the JAK1 gene was an independent risk factor for Behcet's disease (P > 0.05). Real-time PCR analysis showed that no difference on the expression of JAK1 in PBMCs or LPS-stimulated PBMCs between individuals with the different rs1762780815 genotypes studied (P > 0.05). In conclusion, this study suggests that JAK1, but not SLC22A4, SLC22A5 and RUNX1, contributes to the genetic susceptibility to Behcet's disease with ocular involvement.

Gene therapy for noninfectious uveitis

Noninfectious intraocular inflammatory disease remains a significant cause of visual loss, even with current systemic immunosuppression. Alternative novel treatments are thus required, particularly for severe forms of posterior uveitis. Encouraging results from several phase I/II clinical trials of gene therapy for monogenic retinal disorders have paved the way for the development of this approach for other ocular conditions. Gene therapy for uveitis offers the possibility of potent, self-regulating, long-term disease control following a single treatment and without systemic side effects. To date, gene therapy approaches using interleukin-10, interleukin-1 receptor antagonist, interferon-alpha, soluble TNF-alpha receptors, and alpha-MSH gene transfer have been used successfully to attenuate experimental animal models of uveitis. This review evaluates these preclinical studies, considers the route to clinical application, and explores future targets and approaches.

AAV2-mediated combined subretinal delivery of IFN-α and IL-4 reduces the severity of experimental autoimmune uveoretinitis

We previously showed that adeno-associated virus 2 (AAV2) mediated subretinal delivery of human interferon-alpha (IFN-α) could effectively inhibit experimental autoimmune uveoretinitis (EAU). In this study we investigated whether subretinal injection of both AVV2.IFN-α and AAV2.IL-4 had a stronger inhibition on EAU activity. B10RIII mice were subretinally injected with AAV2.IFN-α alone (1.5×10⁷ vg), AAV2.IL-4 alone (3.55×10⁷ vg), and AAV2.IFN-α combined with AAV2.IL-4. PBS, AAV2 vector encoding green fluorescent protein (AAV2.GFP) (5×10⁷ vg) was subretinally injected as a control. IFN-α and IL-4 were effectively expressed in the eyes from three weeks to three months following subretinal injection of AAV2 vectors either alone or following combined administration and significantly attenuated EAU activity clinically and histopathologically. AAV2.IL-4 showed a better therapeutic effect as compared to AAV2.IFN-α. The combination of AAV2.IL-4 and AAV2.IFN-α was not significantly different as compared to AAV2.IL-4 alone. There was no difference concerning DTH (delayed-type hypersensitivity) reaction, lymphocyte proliferation and IL-17 production among the investigated treatment groups, suggesting that local retinal gene delivery did not affect the systemic immune response.

AAV2-mediated subretinal gene transfer of mIL-27p28 attenuates experimental autoimmune uveoretinitis in mice

Background

Advances in gene transfer techniques have provided long-term, safe and stable transduction of retinal cells following subretinal injection with adeno-associated viral (AAV) vectors. In this study we investigated whether subretinal injection of AAV2-murine IL-27p28 vector was effective in inhibiting experimental autoimmune uveoretinitis (EAU) induced in B10RIII mice.

Methodology/Principal Findings

An AAV2 vector encoding the murine IL-27p28 gene (rAAV2-CMV-mIL-27p28) was prepared and subretinally injected into B10RIII mice (4.35×10⁸ vector genome (v.g.)). AAV2 vector mediating green fluorescent protein (rAAV2-CMV-GFP) served as a control (5×10⁸ v.g.). The concentration of mIL-27p28 in homogenized eyes and serum was assayed by enzyme linked immunosorbent assay (ELISA) after subretinal injection. Human IRBP_161–180 peptide and Complete Freund’s Adjuvant were injected into mice receiving either the rAAV2-CMV-mIL-27p28 or rAAV2-CMV-GFP vector. EAU was evaluated clinically and pathologically. The level of IL-17 and IL-10 in homogenized eyes was measured on day 12 and day 21 following immunization. Delayed type hypersensitivity (DTH) and IRBP_161–180–specific proliferation of lymphocytes from the spleen and lymph nodes were assayed to examine the influence of the subretinal delivery of rAAV2-CMV-mIL-27p28 on the systemic immune response. IL-27p28 was detectable by ELISA within the eyes from two weeks following subretinal injection of the rAAV2-CMV-mIL-27p28 vector and showed a sustained high expression from day 14 to 9 months with a highest expression at 5 months. Subretinal injection of the vector significantly attenuated the severity of EAU disease clinically and pathologically in association with a significantly decreased IL-17 expression and an increased IL-10 expression. The IL-27p28 vector did not affect the systemic immune response, as determined by DTH and IRBP_161–180–specific lymphocyte proliferation.

Conclusions/Significance

A high and stable expression of IL-27p28 was observed for at least 9 months following subretinal delivery of rAAV2-CMV-mIL-27p28. The amelioration of EAU disease severity was associated with a decreased IL-17 expression and an increased IL-10 expression.