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1.  Investigation of the peptidoglycan sensing molecule, PGLYRP-2, in murine inflammatory uveitis 
Background/aim
Peptidoglycan (PGN) recognition proteins (PGLYRPs) are innate immune molecules that recognise bacterial cell wall PGN, and participate in several inflammatory diseases such as arthritis. We sought to elucidate the contribution of PGLYRPs in murine uveitis (intraocular inflammatory disease) elicited by PGN, and the extent to which systemically administered PGN alters uveitis compared with arthritis versus locally triggered ocular responses.
Methods
Mice deficient for PGLYRP-2, PGLYRP-3 or PGLYRP-4 were administered PGN by an intraperitoneal or intraocular injection. Arthritis was assessed by near-infrared imaging and histopathology, while uveitis was measured by intravital videomicroscopy and histopathology.
Results
Systemic PGN exposure predisposed to arthritis through a PGLYRP-2 dependent mechanism. By contrast, systemic PGN exposure did not predispose to uveitis, and PGLYRP-2 deficiency had no impact on the development the uveitis. When PGN was administered locally, a robust uveitis ensued, which occurred independently of PGLYRP-2. Regardless of whether PGN was administered systemically or locally, neither PGLYRP-3 nor PGLYRP-4 deficiency significantly altered ocular inflammation compared with wild-type control animals.
Conclusions
Our findings highlight the complexity of PGLYRPs and how PGLYRP-2 may use different molecular pathways in the joints versus eyes. Collectively, our results support a non-essential or redundant role for PGLYRPs-2, -3, -4 in uveitis.
doi:10.1136/bjophthalmol-2012-302650
PMCID: PMC4084548  PMID: 23361435
2.  IFNγ regulates discordant mechanisms of uveitis versus joint and axial disease in a murine model resembling spondyloarthritis 
Arthritis and Rheumatism  2012;64(3):762-771.
OBJECTIVE
The spondyloarthropathies (such as ankylosing spondylitis) are multi-system inflammatory diseases that frequently result in uveitis, or intra-ocular eye inflammation. Despite the common co-occurrence of uveitis with arthritis, there has been no explanation for the eye’s susceptibility to inflammation. Using an innovative intravital videomicroscopic approach, we discovered the co-existence of uveitis with axial and peripheral joint inflammation in mice immunized with cartilage proteoglycan (PG). Here, we elucidate the characteristics of uveitis and test the impact of IFNγ deficiency on the eye versus the joint and spine.
METHODS
Female, TCR-Tg or IFNγ knock-out crossed to TCR-Tg mice were immunized with PG. Uveitis was assessed by intravital videomicroscopy and histology. The clinical and histopathologic severity of arthritis and spondylitis were evaluated. Bone remodeling process within the spine was assessed by whole-body NIR imaging. Immunoblotting and immunofluorescence staining were used to examine expression of PG and ADAMTS-5 along with examination of the cellular composition of uveitic eyes.
RESULTS
PG neo-epitopes along with the aggrecanase, ADAMTS-5, are present in the eye as they are the joint. Anterior uveitis develops in response to PG immunization. The cellular infiltrate consists mainly of neutrophils and eosinophils. Unexpectedly, IFNγ deficiency markedly exacerbates uveitis while ameliorating joint and spine disease, indicating divergent mechanisms that drive diseases in the eye versus joints and spine.
CONCLUSIONS
This is the first detailed description of a murine disease model wherein uveitis coincides with arthritis and spondylitis. Our observations provide great opportunity to understand the pathogenesis of a relatively common but poorly understood disease.
doi:10.1002/art.33404
PMCID: PMC3271189  PMID: 21987263
3.  Neutralization of IL-17 ameliorates uveitis but damages photoreceptors in a murine model of spondyloarthritis 
Introduction
Uveitis, or intraocular inflammatory disease, is a frequent extra-articular manifestation of several forms of arthritis. Despite the frequent co-occurrence of uveitis and arthritis, little is understood of the eye's predisposition to this disease. We recently described a previously unreported uveitis in a murine model of spondyloarthropathy triggered by autoimmunity to aggrecan, a prominent proteoglycan (PG) macromolecule in cartilage. In contrast to the joint and spine, wherein interferon-gamma (IFNγ) deficiency reduced disease, IFNγ deficiency worsened uveitis. Given the regulatory role of IFNγ on the Th17 response and the current focus of anti-interleukin-17 therapeutics in patients with uveitis and spondyloarthritis, we sought to determine the extent to which interleukin (IL)-17 mediates uveitis in the absence of IFNγ.
Methods
Antigen specific T cell cytokine production was measured in splenocyte cultures using multiplex-ELISA. Transgenic (Tg) mice expressing the T cell receptor (TCR) recognizing the dominant arthritogenic epitope in the G1 domain of PG (TCR-Tg), also lacking IFNγ, were immunized with PG. Mice were then systemically administered an anti-IL-17 neutralizing antibody. The onset and severity of peripheral arthritis was evaluated by clinical scoring criteria and histology. Uveitis was assessed using intravital videomicroscopy, which visualizes leukocyte trafficking within the vasculature and tissue of the iris, and by histology.
Results
TCR-Tg splenocytes stimulated in vitro with recombinant G1 peptide demonstrated exacerbated production of cytokines, such as macrophage inflammatory protein (MIP)-1α, MIP-1β, IL-1β, and most notably IL-17A as a consequence of IFNγ deficiency. In vivo, IL-17 inhibition prevented the component of PG-induced arthritis that occurs independently of IFNγ. Blockade of IL-17 ameliorated the ongoing leukocyte trafficking responses within the iris vasculature and tissue, which coincided with reduced infiltration of leukocytes within the anterior and posterior eye segments. However, the anti-IL-17 treatment resulted in unanticipated photoreceptor toxicity.
Conclusions
These data support a protective, regulatory role for IFNγ in suppression of IL-17-mediated intraocular disease and to a lesser extent, joint disease. The unanticipated photoreceptor toxicity raises some caution regarding the use of anti-IL-17 therapeutics until the mechanism of this potential effect is determined.
doi:10.1186/ar3697
PMCID: PMC3392808  PMID: 22269151
4.  NOD2 and TLR2 function independently in a murine model of arthritis triggered by intra-articular peptidoglycan 
Arthritis and rheumatism  2010;62(4):1051-1059.
Objective
Blau syndrome is an autoinflammatory disease resulting from mutations in NOD2 (nucleotide-binding oligomerization domain 2), wherein granulomatous arthritis, uveitis and dermatitis develop. The mechanisms by which aberrant NOD2 causes joint inflammation are poorly understood. Indeed very few studies have addressed NOD2 function in the joint. Here, we investigate NOD2 function in an experimental model of arthritis and explore the potential interplay between TLR2 and NOD2 in joint inflammation.
Methods
Mice deficient for TLR2, MyD88, or NOD2 and their wildtype controls were administered an intra-articular injection of muramyl dipeptide (MDP), peptidoglycan (PGN) (a metabolite of which is MDP), or Pam3CSK4, a synthetic TLR2 agonist. Joint inflammation was assessed using near-infrared fluorescence imaging and histology.
Results
Locally administered PGN results in joint inflammation, which was markedly reduced in mice deficient for either TLR2 or the TLR signaling mediator, MyD88. In addition to TLR2 signaling events, NOD2 mediated joint inflammation since mice deficient for NOD2 showed significantly reduced PGN-induced arthritis. TLR2 or MyD88 deficiency did not influence arthritis induced by the specific NOD2 agonist, MDP. In addition, NOD2 deficiency did not alter TLR2-dependent joint inflammation elicited by the synthetic TLR2 agonist, Pam3CSK4.
Conclusion
Whereas NOD2 and TLR2 are both critical for the development of PGN-arthritis, they appear to elicit inflammation independently of each other. Our studies support an inflammatory role for NOD2 in arthritis.
doi:10.1002/art.27335
PMCID: PMC2945367  PMID: 20131263
5.  NOD2 Deficiency Results in Increased Susceptibility to Peptidoglycan-Induced Uveitis in Mice 
The regulatory roles for NOD2 versus TLR signaling were explored in murine uveitis triggered by peptidoglycan.
Purpose.
The innate immune receptor NOD2 is a genetic cause of uveitis (Blau syndrome). Intriguingly, in the intestine where polymorphisms of NOD2 predispose to Crohn's disease, NOD2 reportedly suppresses inflammation triggered by the bacterial cell wall component, peptidoglycan (PGN). Whether NOD2 exerts a similar capacity in the regulation of ocular inflammation to PGN has not been explored.
Methods.
NOD2, NOD1, or MyD88 knockout (KO) mice and their wild-type (WT) controls were administered an intravitreal injection of PGN (a metabolite of which is the NOD2 agonist, muramyl dipeptide), or synthetic TLR2/1 and TLR2/6 agonists, Pam3CSK4 and FSL-1. Ocular inflammation was assessed by intravital microscopy and histopathology. Cytokine production in eye tissue homogenates was measured by ELISA.
Results.
PGN triggered uveitis in mice. This inflammation was abolished in the absence of the TLR signaling mediator MyD88. NOD2 exerted a negative regulatory role because PGN-triggered eye inflammation was exacerbated in NOD2 KO mice. Increased intravascular response coincided with enhanced leukocytes within the aqueous and vitreous humors. The enhanced susceptibility of NOD2 KO mice to PGN uveitis coincided with increased cytokine production of IL-12p40, IL-17, and IL-23 but not IL-12p70, TNFα, or IFNγ. NOD1 deficiency did not result in the same sensitivity to PGN. Ocular inflammation induced by synthetic TLR2 agonists required MyD88 but not NOD2 or NOD1.
Conclusions.
NOD2 may serve differential roles in the eye to promote inflammation while also tempering cell responses to PGN akin to what has been reported in colitis.
doi:10.1167/iovs.10-6263
PMCID: PMC3175939  PMID: 21296813
6.  NOD1 Expression in the Eye and Functional Contribution to IL-1β–Dependent Ocular Inflammation in Mice 
PURPOSE
NOD1 plays an important role in host defense and recognizes the minimal component of bacterial cell walls, meso-diaminopimelic acid (iE-DAP). Polymorphisms in NOD1 are associated with autoinflammatory diseases characterized by uveitis such as Crohn’s disease and sarcoidosis. NOD1 is homologous to NOD2, which is responsible for an autosomal dominant form of uveitis. Nonetheless, the role of NOD1 in intraocular inflammation has not been explored. The induction of uveitis by iE-DAP in mice and the potential contribution of interleukin (IL)-1β were investigated.
METHODS
BALB/c mice or mice deficient in caspase-1 or IL-1R1 and their congenic controls were injected intravitreally with iE-DAP or saline. The time course, dose response, and contribution of IL-1β to ocular inflammation were quantified by intravital video microscopy, histology, and immunohistochemistry. NOD1 and IL-1β were measured in eye tissue by immunoblotting and ELISA.
RESULTS
NOD1 protein is expressed in the eye and promotes ocular inflammation in a dose- and time-dependent fashion. The authors previously defined the role of IL-1β in NOD2 uveitis and tested whether NOD1 and NOD2 used similar mechanisms. Treatment with iE-DAP significantly increased IL-1β, which was caspase-1 dependent. However, in contrast to NOD2, caspase-1 and IL-1R1 were essential mediators of iEDAP– induced uveitis, suggesting that NOD1 and NOD2 induce ocular inflammation by distinct mechanisms involving IL-1β.
CONCLUSIONS
These findings demonstrate that NOD1 is expressed within the eye and that its activation results in uveitis in an IL-1β–dependent mechanism. Characterizing the differences between NOD1 and NOD2 responses may provide insight into the pathogenesis of uveitis.
doi:10.1167/iovs.08-2852
PMCID: PMC3086269  PMID: 19074813
7.  NOD2, the Gene Responsible for Familial Granulomatous Uveitis, in a Mouse Model of Uveitis 
Purpose
NOD2 plays an important role in the recognition of intracellular bacteria through its ability to sense the components of bacterial peptidoglycan (PGN), namely muramyl dipeptide (MDP) and muramyl tripeptide (MTP). Specific mutations in the human NOD2 gene cause Blau syndrome, an autosomal dominant form of uveitis, arthritis, and dermatitis. As a first step toward understanding the role of NOD2 in the pathogenesis of uveitis, the authors developed a mouse model of MDP-dependent uveitis.
Methods
BALB/c mice and mice deficient in L-selectin or NOD2 received intravitreal injection of MDP, MTP, or PGN. The intravascular response within the iris and cellular infiltration was quantified by intravital microscopy and histologic assessment.
Results
MDP induced an acute, ocular inflammatory response, wherein rolling and adhering leukocytes within the vasculature were significantly increased within 6 hours after MDP treatment. A minor increase in cellular infiltration occurred at 12 hours after MDP treatment. The adhesion molecule L-selectin participated in MDP-induced vascular inflammation because L-selectin knockout mice showed a significant decrease in the number of rolling cells. Importantly, NOD2 plays an essential role in ocular inflammation induced by MDP, as indicated by the fact that uveitis did not develop in Nod2 knockout mice in response to MDP. Nod2 knockout mice also showed abolished ocular inflammation in response to MTP but not to PGN treatment.
Conclusions
These findings demonstrate a novel mouse model of uveitis, wherein NOD2 plays an essential role in inflammation induced by the minimal components of PGN. Thus, innate immune responses mediated by NOD2 may participate in the development of uveitis in response to bacterial products.
doi:10.1167/iovs.07-1174
PMCID: PMC2430189  PMID: 18385071
8.  FcgammaR expression on macrophages is related to severity and chronicity of synovial inflammation and cartilage destruction during experimental immune-complex-mediated arthritis (ICA) 
Arthritis Research  2000;2(6):489-503.
We investigated the role of Fcγ receptors (FcγRs) on synovial macrophages in immune-complex-mediated arthritis (ICA). ICA elicited in knee joints of C57BL/6 mice caused a short-lasting, florid inflammation and reversible loss of proteoglycans (PGs), moderate chondrocyte death, and minor erosion of the cartilage. In contrast, when ICA was induced in knee joints of Fc receptor (FcR) γ-chain-/- C57BL/6 mice, which lack functional FcγRI and RIII, inflammation and cartilage destruction were prevented. When ICA was elicited in DBA/1 mice, a very severe, chronic inflammation was observed, and significantly more chondrocyte death and cartilage erosion than in arthritic C57BL/6 mice. The synovial lining and peritoneal macrophages of naïve DBA/1 mice expressed a significantly higher level of FcγRs than was seen in C57BL/6 mice. Moreover, elevated and prolonged expression of IL-1 was found after stimulation of these cells with immune complexes. Zymosan or streptococcal cell walls caused comparable inflammation and only mild cartilage destruction in all strains. We conclude that FcγR expression on synovial macrophages may be related to the severity of synovial inflammation and cartilage destruction during ICA.
Introduction:
Fcγ receptors (FcγRs) present on cells of the haematopoietic lineage communicate with IgG-containing immune complexes that are abundant in the synovial tissue of patients with rheumatoid arthritis (RA). In mice, three classes of FcγR (RI, RII, and RIII) have been described. Binding of these receptors leads to either activation (FcγRI and RIII) or deactivation (FcγRII) of intracellular transduction pathways. Together, the expression of activating and inhibitory receptors is thought to drive immune-complex-mediated diseases.
Earlier studies in our laboratory showed that macrophages of the synovial lining are of utmost importance in the onset and propagation of immune-complex-driven arthritic diseases. Selective depletion of macrophages in the joint downregulated both inflammation and cartilage destruction. As all three classes of FcγR are expressed on synovial macrophages, these cells are among the first that come in contact with immune complexes deposited in the joint. Recently, we observed that when immune complexes were injected into the knee joints of mice, strains susceptible to collagen-type-II arthritis (DBA/1, B10.RIII) developed more severe arthritis than nonsusceptible strains did, or even developed chronic arthritis. One reason why these strains are more susceptible might be their higher levels of FcγRs on macrophage membranes. To test this hypothesis, we investigated the role of FcγRs in inflammation and cartilage damage during immune-complex-mediated arthritis (ICA). First, we studied arthritis and subsequent cartilage damage in mice lacking functional FcγRI and RIII (FcR γ-chain-/- mice). Next, DBA/1 mice, which are prone to develop collagen-type-II arthritis (`collagen-induced arthritis'; CIA) and are hypersensitive to immune complexes, were compared with control C57BL/6 mice as regards cartilage damage and the expression and function of FcγRs on their macrophages.
Aims:
To examine whether FcγR expression on macrophages is related to severity of synovial inflammation and cartilage destruction during immune-complex-mediated joint inflammation.
Methods:
ICA was induced in three strains of mice (FcR γ-chain-/-, C57BL/6, and DBA/1, which have, respectively, no functional FcγRI and RIII, intermediate basal expression of FcγRs, and high basal expression of FcγRs) by passive immunisation using rabbit anti-lysozyme antibodies, followed by poly-L-lysine lysozyme injection into the right knee joint 1 day later. In other experiments, streptococcal-cell-wall (SCW)- or zymosan-induced arthritis was induced by injecting SCW (25 μg) or zymosan (180 μg) directly into the knee joint. At several time points after arthritis induction, knee joints were dissected and studied either histologically (using haematoxylin/eosin or safranin O staining) or immuno-histochemically. The arthritis severity and the cartilage damage were scored separately on an arbitrary scale of 0-3.
FcγRs were immunohistochemically detected using the monoclonal antibody 2.4G2, which detects both FcγRII and RIII. Deposition of IgG and C3c in the arthritic joint tissue was also detected immunohistochemically. Expression of FcγRs by murine peritoneal macrophages was measured using a fluorescence-activated cell sorter (FACS).
Peritoneal macrophages were stimulated using heat-aggregated gamma globulins (HAGGs), and production of IL-1 was measured using a bioassay. To assess the levels of IL-1 and its receptor antagonist (IL-1Ra) during arthritis, tissue was dissected and washed in RPMI medium. Washouts were tested for levels of IL-1 and IL-1Ra using radioimmunoassay and enzyme-linked immunosorbent assay. mRNA was isolated from the tissue, and levels of macrophage inflammatory protein (MIP)-2, monocyte chemoattractant protein (MCP)-1, IL-1, and IL-1Ra were determined using semiquantitative reverse-transcription polymerase chain reaction (RT-PCR).
Results:
ICA induced in knee joints of C57BL/6 mice caused a florid inflammation at day 3 after induction. To investigate whether this arthritis was FcγR-mediated, ICA was induced in FcR γ-chain-/- mice, which lack functional FcγRI and RIII. At day3, virtually no inflammatory cells were found in their knee joints. Levels of mRNA of IL-1, IL-1Ra, MCP-1, and MIP-2, which are involved in the onset of this arthritis, were significantly lower in FcR γ-chain-/- mice than in control C57BL/6 mice. Levels of IL-1 protein were also measured. At 6 h after ICA induction, FcR γ-chain-/- mice and control C57BL/6 mice showed similar IL-1 production as measured by protein level. By 24 h after induction, however, IL-1 production in the FcR γ-chain-/- mice was below the detection limit, whereas the controls were still producing a significant amount. To investigate whether the difference in reaction to immune complexes between the DBA/1 and C57BL/6 mice might be due to variable expression of FcγRs in the knee joint, expression in situ of FcγRs in naïve knee joints of these mice was determined. The monoclonal antibody 2.4G2, which detects both FcγRII and RIII, stained macrophages from the synovial lining of DBA/1 mice more intensely than those from C57BL/6 mice. This finding suggests a higher constitutive expression of FcγRs by macrophages of the autoimmune-prone DBA/1 mice. To quantify the difference in FcγR expression on macrophages of the two strains, we determined the occurrence of FcγRs on peritoneal macrophages by FACS analysis. The levels of FcγR expressed by macrophages were twice as high in the DBA/1 mice as in the C57BL/6 mice (mean fluorescence, respectively, 440 ± 50 and 240 ± 30 intensity per cell). When peritoneal macrophages of both strains were stimulated with immune complexes (HAGGs), we found that the difference in basal FcγR expression was functional. The stimulated macrophages from DBA/1 mice had significantly higher IL-1α levels (120 and 135 pg/ml at 24 and 48 h, respectively) than cells from C57BL/6 mice (45 and 50 pg/ml, respectively).
When arthritis was induced using other arthritogenic triggers than immune complexes (zymosan, SCW), all the mouse strains tested (DBA/1, FcR γ-chain-/-, and C57BL/6) showed similar inflammation, indicating that the differences described above are found only when immune complexes are used to elicit arthritis.
We next compared articular cartilage damage in arthritic joints of the three mouse strains FcR γ-chain-/-, C57BL/6 (intermediate basal expression of FcγRs), and DBA/1 (high basal expression of FcγRs). Three indicators of cartilage damage were investigated: depletion of PGs, chondrocyte death, and erosion of the cartilage matrix. At day 3 after induction of ICA, there was no PG depletion in FcR γ-chain-/- mice, whereas PG depletion in the matrix of the C57BL/6 mice was marked and that in the arthritic DBA/1 mice was even greater. PG depletion was still massive at days 7 and 14 in the DBA/1 mice, whereas by day 14 the PG content was almost completely restored in knee joints of the C57BL/6 mice. Chondrocyte death and erosion of cartilage matrix, two indicators of more severe cartilage destruction, were significantly higher in the DBA/1 than in the C57BL/6 mice, while both indicators were completely absent in the FcR γ-chain-/- mice. Again, when arthritis was induced using other triggers (SCW, zymosan), all strains showed similar PG depletion and no chondrocyte death or matrix erosion. These findings underline the important role of immune complexes and FcγRs in irreversible cartilage damage.
Discussion:
Our findings indicate that inflammation and subsequent cartilage damage caused by immune complexes may be related to the occurrence of FcγRs on macrophages. The absence of functional FcγRI and RIII prevented inflammation and cartilage destruction after induction of ICA, whereas high basal expression of FcγRs on resident joint macrophages of similarly treated mice susceptible to autoimmune arthritis was correlated with markedly more synovial inflammation and cartilage destruction. The difference in joint inflammation between the three strains was not due to different susceptibilities to inflammation per se, since intra-articular injection of zymosan or SCW caused comparable inflammation. Although extensive inflammatory cell mass was found in the synovium of all strains after intra-articular injection of zymosan, no irreversible cartilage damage (chondrocyte death or matrix erosion) was found. ICA induced in C57BL/6 and DBA/1 mice did cause irreversible cartilage damage at later time points, indicating that immune complexes and FcγRs play an important role in inducing irreversible cartilage damage. Macrophages communicate with immune complexes via Fcγ receptors. Absence of functional activating receptors completely abrogates the synovial inflammation, as was shown after ICA induction in FcR γ-chain-/- mice. However, the γ-chain is essential not only in FcγRI and RIII but also for FcεRI (found on mast cells) and the T cell receptor (TcR)-CD3 (Tcells) complex of γδT cells. However, T, B, or mast cells do not play a role in this arthritis that is induced by passive immunisation. Furthermore, this effect was not caused by a difference in clearance of IgG or complement deposition in the tissue. In this study, DBA/1 mice, which are susceptible to collagen-induced autoimmune arthritis and in a recent study have been shown to react hypersensitively to immune complexes, are shown to express higher levels of FcγRs on both synovial and peritoneal macrophages. Because antibodies directed against the different subclasses of FcγR are not available, no distinction could be made between FcγRII and RIII. Genetic differences in DBA/1 mice in genes coding for or regulating FcγRs may be responsible for altered FcγR expression. If so, these mouse strains would have a heightened risk for immune-complex-mediated diseases.
To provide conclusive evidence for the roles of the various classes of FcγR during ICA, experiments are needed in which FcγRs are blocked with specific antibodies, or in which knockout mice lacking one specific class of FcγR are used. The only available specific antibody to FcγR (2.4G2) has a stimulatory effect on cells once bound to the receptor, and therefore cannot be used in blocking experiments. Experiments using specific knockout mice are now being done in our laboratory.
Macrophages are the dominant type of cell present in chronic inflammation during RA and their number has been shown to correlate well with severe cartilage destruction. Apart from that, in humans, these synovial tissue macrophages express activating FcRs, mainly FcγIIIa, which may lead to activation of these macrophages by IgG-containing immune complexes. The expression of FcRs on the surface of these cells may have important implications for joint inflammation and severe cartilage destruction and therefore FCRs may constitute a new target for therapeutic intervention.
PMCID: PMC17821  PMID: 11056679
autoimmunity; cytokines; Fc receptors; inflammation; macrophages
9.  The NLRP3 inflammasome is active but not essential in endotoxin-induced uveitis 
Inflammation Research  2011;61(3):225-231.
Objective
The inflammasome complex involving caspase-1 and nucleotide-binding domain, leucine-rich repeat containing protein (NLRP)3, also known as NALP3 or cryopyrin is important for host responses to microbial pathogens and several autoinflammatory diseases. We investigated the extent to which NLRP3 and caspase-1 control ocular interleukin (IL)-1β production and severity of uveitis (intraocular inflammatory disease) in an established, acute inflammatory uveitis model, endotoxin-induced uveitis (EIU).
Methods
Expression of NLRP3, its adaptor molecule ASC, also known as PYCARD (PYD and CARD domain containing), and caspase-1 were examined by immunoblotting. IL-1β production was measured by enzyme-linked immunosorbent assay (ELISA). Using knockout mice, roles for caspase-1 and NLRP3 were examined in uveitis induced by intraocular injection of Escherichia coli lipopolysaccharide (LPS).
Results
NLRP3, ASC, and caspase-1 proteins are constitutively expressed in eye tissue. During EIU, IL-1β protein production increases; this requires the presence of both caspase-1 and NLRP3. However, severity of EIU is not altered by deficiency in either caspase-1 or NLRP3, as assessed by both intravital microscopy and histology.
Conclusions
These data identify the importance of the NLRP3 inflammasome for IL-1β production in the eye, yet indicate that its participation in EIU is nonessential.
doi:10.1007/s00011-011-0404-8
PMCID: PMC3335428  PMID: 22119862
NLRP3; Caspase-1; Inflammasome; Uveitis; Mice; Lipopolysaccharide
10.  Long-term efficacy of adalimumab in the treatment of uveitis associated with juvenile idiopathic arthritis 
Background
The purpose of this study was to investigate the long-term effects of adalimumab, a tumor necrosis factor alpha antagonist, in the treatment of uveitis associated with juvenile idiopathic arthritis.
Methods
Adalimumab was initiated in 94 patients with juvenile idiopathic arthritis to treat active arthritis and/or active associated uveitis. In 18 patients, therapy was discontinued after a short period because of inefficacy or side effects. The activity of uveitis (using Standardized Uveitis Nomenclature [SUN] criteria and clinical examination) and arthritis (number of swollen or active joints) was evaluated at the start and at end of the study.
Results
At the end of the study, uveitis was under good clinical control in two thirds of 54 patients (31% did not need any local treatment and 35% used only 1–2 corticosteroid drops a day), and one third had active uveitis (at least three corticosteroid drops a day). According to SUN criteria, adalimumab treatment for uveitis showed improved activity (a two-fold decrease in uveitis activity) in 28% of patients, with a moderate response in 16 patients, no change in a further 16 patients, and worsening activity (a two-fold increase in uveitis activity) in 13% of patients. The overall proportion of patients with active arthritis decreased. At the beginning of the study, 69% of patients with uveitis had more than two active joints, and at the end of the study only 27% had active joint disease. In 27 patients with juvenile idiopathic arthritis without uveitis on adalimumab, the number of active joints decreased from 93% to 59%. Systemic corticosteroid treatment could be stopped in 22% of patients with uveitis and in 11% of those without uveitis. Most of the patients had received methotrexate, other immunosuppressive therapy, or other biological drugs before initiating adalimumab.
Conclusion
Adalimumab is a valuable option in the treatment of uveitis associated with active juvenile idiopathic arthritis.
doi:10.2147/OPTH.S23646
PMCID: PMC3198418  PMID: 22034564
adalimumab; juvenile idiopathic arthritis; uveitis
11.  Nucleotide Oligomerization Domain-2 (NOD2)-Induced Uveitis: Dependence on IFN-γ 
Purpose
Nucleotide oligomerization domain-2 (NOD2) plays an important role in innate immunity to sense muramyl dipeptide (MDP), a component of bacterial cell walls. Notably, NOD2 is linked to eye inflammation because mutations in NOD2 cause a granulomatous type of uveitis called Blau syndrome. A mouse model of NOD2-dependent ocular inflammation was employed to test the role of a cytokine strongly implicated in granuloma formation, IFN-γ, in order to gain insight into downstream functional consequences of NOD2 activation within the eye triggering uveitis.
Methods
Mice deficient in IFN-γ, NOD2, or CD11b and their wild-type controls were treated with intravitreal injection of MDP in the presence or absence of IFN-γ. IFN-γ production in the eye was measured by ELISA. The intravascular inflammatory response within the iris was quantified by intravital microscopy.
Results
NOD2 activation resulted in the production of IFN-γ within the eye. Deficiency in IFN-γ diminished the development of MDP-induced uveitis, indicating its crucial role in downstream inflammatory events triggered by NOD2. Moreover, exogenous IFN-γ markedly exacerbated MDP-induced ocular inflammation in a NOD2-dependent mechanism. The potential of IFN-γ to enhance inflammation required the adhesion molecule CD11b because CD11b-deficient mice failed to show the synergistic effects of IFN-γ and MDP cotreatment on adhering and infiltrating cells.
Conclusions
IFN-γ was identified as a downstream mediator of NOD2-driven inflammation and the capacity of IFN-γ in vivo to enhance the inflammatory potential of NOD2 was demonstrated. Extrapolation of these findings in mice suggests that the dysregulation of IFN-γ may occur in patients with Blau syndrome, thereby contributing to the granulomatous nature of the disease.
doi:10.1167/iovs.08-2756
PMCID: PMC3089593  PMID: 19098321
12.  A randomised controlled trial of the clinical effectiveness, safety and cost-effectiveness of adalimumab in combination with methotrexate for the treatment of juvenile idiopathic arthritis associated uveitis (SYCAMORE Trial) 
Trials  2014;15:14.
Background
Juvenile idiopathic arthritis (JIA) is the most common rheumatic disease in children. Children with JIA are at risk of inflammation of the uvea in the eye (uveitis). Overall, 20% to 25% of paediatric uveitis is associated with JIA. Major risk factors for development of uveitis in JIA are oligoarticular pattern of arthritis, an age at onset of arthritis of less than seven years of age, and antinuclear antibody positivity. In the initial stages of mild to moderate inflammation the uveitis is asymptomatic. This has led to current practice of screening all children with JIA for uveitis. Approximately 12% to 38% of patients with JIA develop uveitis in seven years following onset of arthritis. In 30% to 50% of children with JIA-associated uveitis structural complications are present at diagnosis. Furthermore about 50% to 75% of those with severe uveitis will eventually develop visual impairment secondary to ocular complications such as cataract and glaucoma. Defining the severity of inflammation and structural complications in uveitis patients is now possible following Standardised Uveitis Nomenclature (SUN) guidelines, and modified to incorporate the consensus of end point and outcome criteria into the design of randomised trials. Despite current screening and therapeutic options (pre-biologics) 10% to 15% of children with JIA-associated uveitis may develop bilateral visual impairment and certified legally blind. To date, there remains no controlled trial evidence of benefits of biologic therapy.
Methods/design
This study will randomise 154 patients aged 2 to 18 years with active JIA-associated uveitis (despite methotrexate (MTX) treatment for at least 12 weeks). All participants will be treated for 18 months, with follow up of 3 years from randomisation (continuing on MTX throughout). All participants will receive a stable dose of MTX and in addition either adalimumab (20 mg/0.8 ml for patients <30 kg or 40 mg/0.8 ml for patients weighing 30 kg or more, subcutaneous (s/c) injection every 2 weeks based on body weight), or placebo (0.8 ml as appropriate according to body weight) s/c injection every 2 weeks.
Discussion
This is the first randomised controlled trial that will assess the clinical effectiveness, safety and cost effectiveness of adalimumab in combination with methotrexate for the treatment of juvenile idiopathic arthritis associated uveitis.
Trial registration
ISRCTN10065623
doi:10.1186/1745-6215-15-14
PMCID: PMC3892031  PMID: 24405833
Adalimumab; Juvenile idiopathic arthritis; Methotrexate; Ophthalmology; Paediatric; Rheumatology; Safety; Uveitis
13.  Gene therapy for established murine collagen-induced arthritis by local and systemic adenovirus-mediated delivery of interleukin-4 
Arthritis Research  2000;2(4):293-302.
To determine whether IL-4 is therapeutic in treating established experimental arthritis, a recombinant adenovirus carrying the gene that encodes murine IL-4 (Ad-mIL-4) was used for periarticular injection into the ankle joints into mice with established collagen-induced arthritis (CIA). Periarticular injection of Ad-mIL-4 resulted in a reduction in the severity of arthritis and joint swelling compared with saline- and adenoviral control groups. Local expression of IL-4 also reduced macroscopic signs of joint inflammation and bone erosion. Moreover, injection of Ad-mIL-4 into the hind ankle joints resulted in a decrease in disease severity in the untreated front paws. Systemic delivery of murine IL-4 by intravenous injection of Ad-mIL-4 resulted in a significant reduction in the severity of early-stage arthritis.
Introduction:
Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease that is characterized by joint inflammation, and progressive cartilage and bone erosion. Recent research has identified certain biologic agents that appear more able than conventional therapies to halt effectively the progression of disease, as well as ameliorate disease symptoms. One potential problem with the use of biologic agents for arthritis therapy is the need for daily or weekly repeat dosing. The transfer of genes directly to the synovial lining can theoretically circumvent the need for repeat dosing and reduce potential systemic side effects [1,2]. However, although many genes have been effective in treating murine CIA if administrated at a time before disease onset, local intra-articular or periarticular gene transfer has not been highly effective in halting the progression of established disease. IL-4, similar to tumor necrosis factor (TNF)-α and IL-1 inhibitors, has been shown be therapeutic for the treatment of murine CIA when administered intravenously as a recombinant protein, either alone or in combination with IL-10. IL-4 can downregulate the production of proinflammatory and T-helper (Th)1-type cytokines by inducing mRNA degradation and upregulating the expression of inhibitors of proinflammatory cytokines such as IL-1 receptor antagonist (IL-1Ra) [3,4]. IL-4 is able to inhibit IL-2 and IFN-γ production by Th1 cells, resulting in suppression of macrophage activation and the production of the proinflammatory cytokines IL-1, IL-6, IL-8, and TNF-α by monocytes and macrophages [4,5,6,7,8,9].
Objective:
In order to examine the therapeutic effects of local and systemic IL-4 expression in established CIA, an adenoviral vector carrying the gene for murine IL-4 (Ad-mIL-4) was generated. The ability of Ad-mIL-4 to treat established CIA was evaluated by local periarticular and systemic intravenous injection of Ad-mIL-4 into mice at various times after disease onset.
Materials and methods:
Male DBA/1 lacJ (H-2q) mice, aged 7-8 weeks, were purchased from The Jackson Laboratory (Bar Harbor, ME, USA). The mice were immunized intradermally at the base of tail with 100 μ g bovine type II collagen. On day 21 after priming, mice received a boost injection (intradermally) with 100 μ g type II collagen in incomplete adjuvant. For the synchronous onset of arthritis, 40 μ g lipopolysaccharide (Sigma, St Louis, MO, USA) was injected intraperitoneally on day 28. Ad-mIL-4 was injected periarticularly into the hind ankle joints of mice on day 32 or intravenously by tail vein injection on day 29. Disease severity was monitored every other day using an established macroscopic scoring system ranging from 0 to 4: 0, normal; 1, detectable arthritis with erythma; 2, significant swelling and redness; 3, severe swelling and redness from joint to digit; and 4, maximal swelling with ankylosis. The average of macroscopic score was expressed as a cumulative value for all paws, with a maximum possible score of 16 per mouse. Cytokine production by joint tissue or serum were assessed using enzyme-linked immunosorbent assay (ELISA; R&D Systems, Minneapolis, MN, USA).
Results:
To examine the therapeutic effects of IL-4 gene transfer in a murine model of arthritis, 5×108 particles of Ad-mIL-4 and enhanced green fluorescent protein (Ad-eGFP) were administered by periarticular injection into the ankle joints of mice with established disease 4 days after lipopolysaccharide injection. All mice had established disease at time of injection. As shown in Figure 1, the severity of arthritis (Fig. 1a), paw thickness (Fig. 1b), and the number of arthritic paws (Fig. 1c) were all significantly reduced in the Ad-mIL-4 group, compared with the saline- and Ad-eGFP-treated groups. Analysis of the bones in the ankle joints of control arthritic mice showed evidence of erosion with an associated monocytic infiltrate around the joint space compared with the Ad-mIL-4-treated and nonarthritic control joints. In addition, injection of the ankle joints in the hind legs resulted in a therapeutic effect in the front paws. A similar contralateral effect has been observed with adenoviral-mediated delivery of viral (v)-IL-10. Interestingly, a high level of murine IL-10 also was detected from the joint lysates of Ad-mIL-4-treated naïve and arthritic mice, with the production of endogenous IL-10 correlating with the dose of Ad-mIL-4. The administration of recombinant IL-4 protein systemically has been shown to be therapeutic in murine CIA models if given before disease onset. To examine the effect of systemic IL-4 delivered by gene transfer, 1×109 particles of Ad-mIL-4 were injected via the tail vein of collagen-immunized mice the day after lipopolysaccharide injection. Whereas the immunized control mice, injected with Ad-eGFP, showed disease onset on day 3 after lipopolysaccharide injection, Ad-mIL-4-treated mice showed a delay in disease onset and as a reduction in the total number of arthritic paws. Also, systemic injection of Ad-mIL-4 suppressed the severity of arthritis in CIA mice according to arthritis index.
Discussion:
Gene therapy represents a novel approach for delivery of therapeutic agents to joints in order to treat the pathologies associated with RA and osteoarthritis, as well as other disorders of the joints. In the present study we examined the ability of local periarticular and systemic gene transfer of IL-4 to treat established and early-stage murine CIA, respectively. We have demonstrated that both local and systemic administration of Ad-mIL-4 resulted in a reduction in the severity of arthritis, as well as in the number of arthritic paws. In addition, the local gene transfer of IL-4 reduced histologic signs of inflammation and of bone erosion. Interestingly, local delivery of Ad-mIL-4 was able to confer a therapeutic effect to the untreated, front paws through a currently unknown mechanism. In addition, both local and systemic expression of IL-4 resulted in an increase in the level of endogenous IL-10, as well as of IL-1Ra (data not shown). Previous experiments have shown that gene transfer of IL-10 and IL-1 and TNF inhibitors at the time of disease initiation (day 28) is therapeutic. However, delivery of these agents after disease onset appeared to have only limited therapeutic effect. In contrast, the present results demonstrate that IL-4, resulting from local periarticular and systemic injection of Ad-mIL-4, was able partially to reverse progression of established and early-stage disease, respectively. These results, as well as those of others, support the potential application of IL-4 gene therapy for the clinical treatment of RA.
PMCID: PMC17812  PMID: 11056670
adenoviral vectors; collagen-induced arthritis; gene therapy; IL-4; IL-10; rheumatoid arthritis
14.  CXCR4 But Not CXCR7 Is Mainly Implicated in Ocular Leukocyte Trafficking During Ovalbumin-Induced Acute Uveitis 
Experimental eye research  2009;89(4):522-531.
Uveitis is an inflammatory ocular disease characterized by the infiltration of T lymphocytes and other leukocytes into the eye. The recruitment of these inflammatory cells from systemic vasculature to ocular tissue is a well-coordinated multistep process including rolling, firm adhesion and transmigration. CXCL12 (SDF-1α) is an endothelial cell-derived cytokine interacting with CXCR4 and CXCR7, two chemokine receptors mainly expressed in T cells, neutrophils and monocytes. Recent studies have shown that CXCR4, CXCR7 and their ligand, CXCL12, are important for the regulation of leukocyte mobilization and trafficking. However, it is unclear whether these two chemokine receptors are implicated in the pathogenesis of uveitis. In this study, we used DO11.10 mice, whose CD4+ T cells are genetically engineered to react with ovalbumin (OVA), to investigate the role of CXCR4 and CXCR7 in an animal model of uveitis. Intravital microscopy revealed that intravitreal OVA challenge of DO11.10 mice caused the infiltration of both T cells and neutrophils. The invasion of these inflammatory cells coincided with the detection of transcriptional upregulation of CXCR4 and CXCR7 in the eye. In addition, both real time-PCR and immunohistochemistry revealed an enhanced expression of endothelial CXCL12. Furthermore, intraperitoneal injection of AMD3100 (a specific CXCR4 antagonist) significantly attenuated OVA-induced uveitis and CXCL12-mediated transwell migration. In contrast, intraperitoneal administration of CXCR7 neutralizing antibody did not significantly alter ocular infiltration of inflammatory cells caused by OVA challenge. Our data suggest that CXCR4 but not CXCR7 plays a critical role in antigen-induced ocular inflammation by facilitating leukocyte infiltration. This study not only enhances our knowledge of the immunopathological mechanism of uveitis but also provides a novel rationale to target CXCR4 as an anti-inflammatory strategy to treat uveitis.
doi:10.1016/j.exer.2009.05.012
PMCID: PMC2745349  PMID: 19524567
CXCL12; CXCR4; CXCR7; neutrophils; monocytes; ocular inflammation; T cells; uveitis
15.  Comparative Analysis of Induced vs. Spontaneous Models of Autoimmune Uveitis Targeting the Interphotoreceptor Retinoid Binding Protein 
PLoS ONE  2013;8(8):e72161.
Animal models of autoimmunity to the retina mimic specific features of human uveitis, but no model by itself reproduces the full spectrum of human disease. We compared three mouse models of uveitis that target the interphotoreceptor retinoid binding protein (IRBP): (i) the “classical” model of experimental autoimmune uveitis (EAU) induced by immunization with IRBP; (ii) spontaneous uveitis in IRBP T cell receptor transgenic mice (R161H) and (iii) spontaneous uveitis in Autoimmune Regulator (AIRE)−/− mice. Disease course and severity, pathology and changes in visual function were studied using fundus imaging and histological examinations, optical coherence tomography and electroretinography. All models were on the B10.RIII background. Unlike previously reported, IRBP-induced EAU in B10.RIII mice exhibited two distinct patterns of disease depending on clinical scores developed after onset: severe monophasic with extensive destruction of the retina and rapid loss of visual signal, or lower grade with a prolonged chronic phase culminating after several months in retinal degeneration and loss of vision. R161H and AIRE−/− mice spontaneously developed chronic progressive inflammation; visual function declined gradually as retinal degeneration developed. Spontaneous uveitis in R161H mice was characterized by persistent cellular infiltrates and lymphoid aggregation, whereas AIRE−/− mice characteristically developed multi-focal infiltrates and severe choroidal inflammation. These data demonstrate variability and unique distinguishing features in the different models of uveitis, suggesting that each one can represent distinct aspects of uveitis in humans.
doi:10.1371/journal.pone.0072161
PMCID: PMC3756070  PMID: 24015215
16.  Activation of OX40 Prolongs and Exacerbates Autoimmune Experimental Uveitis 
This study reveals an important role for OX40-mediated T-cell costimulation in the development of uveitis.
Purpose.
T cells are essential for the development of autoimmune uveitis. Although the costimulatory molecule OX40 promotes T-cell function and expansion, it is unclear whether OX40 is implicated in ocular inflammation. The purpose of this study was to examine the role of OX40 in uveitis.
Methods.
Experimental autoimmune uveitis (EAU) was induced in B10.RIII mice by subcutaneous injection of interphotoreceptor retinoid-binding protein peptide 161–180 (IRBP161–180). Some mice received an intravenous administration of OX40-activating antibody on days 0 and 4 after IRBP161–180 sensitization or on days 10 and 14 of uveitis onset. The severity of EAU was evaluated by histology at different time points. In addition, ocular inflammatory cytokine expression was determined by real time-PCR, and peripheral activated CD4+CD44+CD62L− T cells and IL-7Rα expression were analyzed by flow cytometry. The activated CD4+CD44+ lymphocytes were rechallenged with IRBP161–180 in vitro to assess their antigen recall response.
Results.
The authors demonstrated a marked OX40 expression by infiltrating lymphocytes in enucleated human eyes with end-stage inflammation. In addition, the administration of OX40-activating antibody prolonged and exacerbated the disease course of EAU. Moreover, activation of OX40 not only increased CD4+CD44+CD62L− lymphocyte number, it upregulated IL-7Rα expression in the activated T-cell population. Lastly, these cells exhibited a stronger interferon-γ response to IRBP161–180 restimulation in vitro.
Conclusions.
The results reveal a pathogenic role of OX40 in uveitis. Furthermore, the upregulation of IL-7R in CD4+CD44+ lymphocytes suggests that the activation of OX40 promotes the generation or expansion of uveitogenic memory T cells.
doi:10.1167/iovs.11-7664
PMCID: PMC3208192  PMID: 21948545
17.  Psoriasis and uveitis: a literature review* 
Anais brasileiros de dermatologia  2012;87(6):877-883.
Psoriasis is a systemic, chronic, immunologically mediated disease, with significant genetic and environmental influences. It affects from 1 to 3% of the world population. Recently, the relation between psoriasis and different comorbidities, particularly metabolic syndrome, has become extremely relevant. Uveitis is characterized by a process of intraocular inflammation resulting from various causes. Considering psoriasis and uveitis as immune-mediated diseases, this study aims to evaluate the possible association of psoriasis and/or psoriatic arthritis with uveitis and its subtypes. Few studies have evaluated the association of uveitis and psoriasis without joint involvement. It seems that psoriasis without arthropathy is not a risk factor for the development of uveitis. Uveitis tends to develop more frequently in patients with arthropathy or pustular psoriasis than in patients with other forms of psoriasis. Ophthalmic examination should be performed periodically in patients with psoriasis and uveitis. If ophthalmopathy is diagnosed, the patient should receive adequate treatment with anti-inflammatory drugs or immunomodulators to prevent vision loss.
doi:10.1590/S0365-05962012000600009
PMCID: PMC3699904  PMID: 23197207
Arthritis, psoriatic; Psoriasis; Uveitis
18.  STAT3 Activates miR-155 in Th17 Cells and Acts in Concert to Promote Experimental Autoimmune Uveitis 
Purpose.
MicroRNA-155 (miR-155) and STAT3 are implicated in uveitis and pathogenic mechanisms of CNS autoimmune diseases. In our study, we used miR-155−/− mice and mice with targeted STAT3 deletion in T cells (CD4-STAT3KO) to investigate roles of miR-155 and STAT3 in the development of experimental autoimmune uveitis (EAU), a mouse model of human uveitis.
Methods.
We induced EAU in WT, miR-155−/−, or CD4-STAT3KO mice by immunization with interphotoreceptor retinoid-binding protein/complete Freund's adjuvant (IRBP/CFA) or adoptive transfer of T cells. EAU was assessed by funduscopy and histology. RNA expression was analyzed by quantitative PCR (qPCR), while cytokine production was assessed by fluorescence-activated cell sorting (FACS).
Results.
We used a combination of genomic and genetic tools to provide the first evidence that STAT3 binds directly to the miR-155 locus and that STAT3 is required for miR-155 expression. Furthermore, STAT3-dependent increase in miR-155 expression in vivo correlated temporally with onset of EAU, and miR-155−/− or CD4-STAT3KO mice did not suffer EAU. CD4+ lymph node cells from IRBP-immunized WT mice transferred EAU to naïve wild-type (WT) and miR-155−/− mice, while miR-155−/− IRBP-specific T cells did not.
Conclusions.
Although miR-155 and STAT3 have been implicated in the etiology of multiple sclerosis (MS), uveitis, or rheumatoid arthritis, their exact roles in these diseases are unclear. We show here for the first time to our knowledge that STAT3 regulates miR-155 expression in Th17 cells. We show further that STAT3 and miR-155 form an axis that promotes the expansion of pathogenic Th17 cells that mediate uveitis. Thus, STAT3 and miR-155 may be therapeutic targets for treating uveitis and other Th17-mediated inflammatory disorders.
We show for the first time, to our knowledge, that STAT3 regulates miR-155 expression by Th17 cells and a STAT3/miR-155 axis mediates uveitis by promoting Th17 expansion. Data suggest that therapeutic strategies that combine miR-155 inhibition with blockade of STAT3 signaling may ameliorate Th17-mediated autoimmune disease.
doi:10.1167/iovs.13-11937
PMCID: PMC3680004  PMID: 23674757
EAU; STAT3; miR-155; uveitis; Th17 cells
19.  Characterisation of uveitis in patients with psoriatic arthritis 
OBJECTIVE—The purpose of this study is to describe the clinical characteristics of uveitis related to psoriatic arthritis (PsA), and also to compare the uveitis in PsA to the uveitis in spondyloarthropathy (SA).
METHODS—Sixteen patients with uveitis and PsA were evaluated in a tertiary care uveitis clinic. These patients were compared retrospectively to a series of 89 patients with uveitis and SA.
RESULTS—Eight (50%) of the 16 patients with uveitis had strictly peripheral arthritis, while two (12.5%) had axial only, and six (37.5%) had axial and peripheral arthritis. Patients with uveitis and axial disease were more likely to be male (100% v 38%) and HLA-B27 positive (6 of 6 typed positive v 0 of 3 typed positive) when compared with those with uveitis and peripheral arthritis only. Compared with patients with SA, those with PsA were more likely to have insidious onset (19% v 3%), simultaneously bilateral (37.5% v 7%), chronic duration (31% v 6%), or posterior (44% v 17%) uveitis. Complications of uveitis were similar in the SA and PsA groups.
CONCLUSION—Uveitis in patients with PsA was more likely to be insidious in onset, continuous, posterior, and active bilaterally compared with uveitis in patients with SA. Patients with uveitis and axial involvement were more likely to be male and HLA-B27 positive compared with patients with uveitis and peripheral arthritis alone. Patients with seronegative arthritis and uveitis that begins insidiously, lasts longer than six months, is bilateral, or is posterior, should be carefully questioned about the presence of either psoriasis or inflammatory bowel disease.


doi:10.1136/ard.59.1.67
PMCID: PMC1752985  PMID: 10627431
20.  Nitric oxide and peroxynitrite production in ocular inflammation. 
Environmental Health Perspectives  1998;106(Suppl 5):1145-1149.
Recent studies have implicated nitric oxide and peroxynitrite in the pathogenesis of many diseases, such as septic shock, arthritis, lung disease, and atherosclerosis. Nitric oxide (.NO) exerts many diverse effects on vascular tone, affecting neurotransmission and cellular cytotoxicity/communication. Our laboratory and others have documented a proinflammatory role for .NO in ocular inflammation. Uveitis, which is an inflammation of the highly vascular uveal tract in the eye, is a debilitating condition that can lead to visual impairment and blindness. It is characterized by acute, recurrent, or persistent inflammation with disruption of the blood-aqueous barrier and is accompanied by protein leakage and leukocyte infiltration into the aqueous humor and anterior chamber. Systemic injection of endotoxin into mice and rats, or intraocular injection of endotoxin into mice, rats, and rabbits induces acute uveitis, which clinically and histologically resembles acute anterior uveitis in humans. These models facilitate the study of pathogenic mechanisms that contribute to ocular inflammation. In addition to .NO, superoxide anion radicals (O2.-), and peroxynitrite (ONOO-), the products of the reaction between .NO and O2.-, are also implicated in uveitis. The role of peroxynitrite in ocular inflammation is still largely unknown. Characterization of the roles of these important uveitic mediators in the ocular inflammatory response will provide information critical to the understanding of the pathogenesis of intraocular inflammation so that more effective therapeutic intervention(s) can be developed.
PMCID: PMC1533362  PMID: 9788889
21.  Uveitis in young adults with juvenile idiopathic arthritis: a clinical evaluation of 123 patients 
Annals of the Rheumatic Diseases  2005;64(6):871-874.
Objective: To examine the prevalence and characteristics of uveitis in young adults with juvenile idiopathic arthritis (JIA).
Methods: The study population consisted of 123 JIA patients born between 1976 and 1980 whose arthritis had been diagnosed and treatment first started at the Rheumatism Foundation Hospital in 1976 to 1995. A clinical re-evaluation was carried out by an ophthalmologist and a paediatric rheumatologist 16 years later on average.
Results: The mean age of the patients was 23.5 years, 72% were women, and 63% had oligoarthritis. During the course of the disease, diagnosis of uveitis had been made in 25 patients (20%). Arthritis in the 19 patients with asymptomatic uveitis was more often ongoing than in the 98 patients without uveitis (p = 0.032). Asymptomatic uveitis was persistent in eight of the 19 cases (42%), and arthritis was active in seven of these. Four of the six patients with attacks of symptomatic uveitis had parallel treatment for arthritis. In three of 19 patients with asymptomatic uveitis and in five of six with acute uveitis the eye inflammation had started after the age of 16. At the onset of arthritis the patients with asymptomatic uveitis were younger than those without uveitis (p = 0.002). Complications of uveitis developed in six patients but their sight remained good.
Conclusions: Asymptomatic uveitis continued into adulthood in almost half the uveitis patients. Most also had ongoing arthritis. Acute uveitis was often associated with persistent arthritis.
doi:10.1136/ard.2004.026955
PMCID: PMC1755508  PMID: 15897307
22.  Potential Role of Decoy B7-H4 in the Pathogenesis of Rheumatoid Arthritis: A Mouse Model Informed by Clinical Data 
PLoS Medicine  2009;6(10):e1000166.
Finding an association between soluble B7-H4 and rheumatoid arthritis severity, Lieping Chen and colleagues use a mouse model to show that the soluble form blocks the inhibitory function of cell-surface B7-H4.
Background
A pathogenic hallmark of rheumatoid arthritis (RA) is persistent inflammatory responses in target tissues and organs. Immune responses mediated by T cells and autoantibodies are known to play pivotal roles. A possible interpretation for this observation is a loss of negative regulation of autoimmune responses. Here we sought to investigate whether B7-H4, a cell surface inhibitory molecule of the B7-CD28 signaling pathway, may play a role in the pathogenesis of RA.
Methods and Findings
In a cross-sectional study of a clinical convenience sample using monoclonal antibodies against human B7-H4 molecules, we detected high levels of the soluble form of B7-H4 (sH4) in the sera of 65% of patients with RA (n = 68) versus only 13% of healthy donors (n = 24). Elevated sH4 was associated with an increased disease severity score (DAS28) in a cross-sectional analysis. In a mouse model of RA, transgenic expression of sH4 or genetic deletion of B7-H4 accelerated the progression of collagen-induced arthritis, accompanied by enhanced T and B cell–mediated autoimmune responses as well as increased activity of neutrophils. Expression in vivo of an agonist, a B7-H4-immunoglobulin Fc fusion protein, profoundly suppressed disease progression in the mouse model.
Conclusions
Our findings in mice indicate that sH4 acts as a decoy molecule to block the inhibitory functions of cell-surface B7-H4, leading to exacerbation of collagen-induced arthritis. If the preliminary correlation between sH4 levels and disease activity in patients with RA can be confirmed to reflect a similar mechanism, these findings suggest a novel target for treatment approaches.
Please see later in the article for the Editors' Summary
Editors' Summary
Background
Rheumatoid arthritis (RA) is a chronic disease caused by abnormal immune responses. In RA, the body's own immune system mainly attacks the joints, causing inflammation in their lining, but can affect other tissues and organs in the body. About 1% of the population in developed countries suffer from RA, and it can result in long-term joint damage, causing significant illness and disability. Sufferers have chronic pain, loss of function of the joint, and loss of mobility. The cause of RA is unknown and there is no known cure. However, neutrophils (an immune cell important for inflammation) are thought to contribute to the initiation of RA. Understanding the primary mechanisms behind the development of RA, and where the body's immune system goes wrong, is fundamental not only to find new treatments for the disease but also to aid diagnosis to help patients get treatment to help control their often debilitating symptoms.
Why Was the Study Done?
Regulation of the immune system is necessary to prevent overactivity. Interruptions to the normal signals that moderate the immune response can lead to destruction of normal tissues. Previous studies have shown that the B7 family of proteins, which interact with CD28 signaling proteins on the surface of immune cells, are important regulators of the immune response. B7 proteins have also been found to exist in soluble forms that have been implicated in the development of rheumatoid diseases, but their exact role is not well understood. In the current study, researchers examined a member of the B7 family, B7-H4, which normally acts as an inhibitor of the immune response, to find out whether this signaling molecule affects the immune response and has a role in the development of RA.
What Did the Researchers Do and Find?
The researchers collected blood from 68 patients with RA and 24 healthy volunteers, and measured levels of soluble B7-H4, also known as sH4. They found sH4 in blood from 65% of patients with RA, compared with only 13% of healthy people. The levels of sH4 were significantly higher in RA patients (96.1 ng/ml) compared to healthy people (<5 ng/ml). Moreover, the highest levels of sH4 were found in patients with the most severe forms of RA, as measured by a standard index score that includes general health, the number of swollen joints, and the amount of inflammation. The researchers then used a mouse model of RA to explore how sH4 might contribute to RA. First, they injected mice with plasmids (circular pieces of DNA that can be used to transfer genes into organisms) carrying the gene for sH4 and looked at how overexpression of sH4 affected the development of arthritis. They also looked at how deleting the B7-H4 gene in mice affected symptoms. Both overexpression of sH4 and deletion of B7-H4 caused inflammation in the mice; symptoms appeared earlier and were more severe. Furthermore, the effects of sH4 were shown to be dependent on neutrophils. Finally, the researchers successfully prevented the development of disease in mice by using a protein to mimic the normal signaling by B7-H4, which inhibits the immune response.
What Do these Findings Mean?
These findings suggest that the signaling molecule B7-H4 may be involved in the development of RA. B7-H4 normally acts as an inhibitor of the immune response to suppress inflammation, but when its action is blocked the immune response is no longer suppressed, and an inappropriate and increased immune reaction occurs. sH4 is thought to act as a decoy that blocks binding of B7-H4 to its receptor, thereby preventing an inhibitory signal to the immune system. Overexpression of sH4 worsens the symptoms in the mouse model of RA. Intriguingly, high levels of sH4 were also present in RA patients and were associated with increased severity of disease. This study does not establish sH4 as a cause of RA but implicates sH4 as a cause in the progression of increased inflammation in this disease. Immune system signaling molecules have potential as novel targets for treatment of RA and other autoimmune disorders. However, further studies are needed to test whether sH4 has a direct role in the development of RA in humans.
Additional Information
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1000166.
MedlinePlus has a topic page on RA providing extensive information on symptoms and treatment for RA and access to related clinical trials and medical literature
The National Rheumatoid Arthritis Society (UK) is a patient-led charity to provide information, education, and support for people with RA
The Arthritis Foundation (US) is a national not-for-profit organization that supports public health education and research funding, and provides informational resources for people with arthritis http://www.arthritis.org/
doi:10.1371/journal.pmed.1000166
PMCID: PMC2760136  PMID: 19841745
23.  Management and evaluation of extra-articular manifestations in spondyloarthritis 
Spondyloarthritis (SpA) is a chronic inflammatory disease with either predominantly axial symptoms of the spine and sacroiliac joints (axial SpA, including ankylosing spondylitis) or predominantly arthritis (peripheral SpA). Next to these spinal and articular symptoms, many patients with SpA also have extra-articular manifestations (EAMs). EAMs associated with SpA include anterior uveitis (25–30%), psoriasis (10–25%) or inflammatory bowel disease (IBD) (5–10%) and cardiovascular manifestations. Peripheral arthritis occurs in approximately 30% of patients, especially in large joints, and shows an asymmetrical, oligoarticular pattern. Other common joint complaints are due to enthesitis, which manifest as extra-articular bony tenderness in areas such as the Achilles tendon. Acute anterior uveitis presents with acute pain, loss of vision and redness in one eye that usually subsides spontaneously after several weeks. Rapid treatment by an ophthalmologist is required to prevent synechiae formation which could ultimately result in glaucoma and blindness. Although less common, organ involvement in SpA can also be located in the heart, lungs or kidneys. The risk of cardiovascular events is increased in SpA. Cardiac manifestations can involve the aortic valve (1–10%) or the atrioventricular node and the risk of atherosclerotic events is increased in this group. Treatment of SpA includes physical exercise and nonsteroidal anti-inflammatory drugs (NSAIDs), and in case of peripheral arthritis, sulphasalazine can be added. When there is insufficient response to NSAIDs, tumor necrosis factor blockers, especially infliximab, etanercept, adalimumab and golimumab, are very effective in treating axial manifestations, arthritis, enthesitis and psoriasis. Anterior uveitis in SpA can be treated adequately by the ophthalmologist and in the case of refractory uveitis, treatment with adalimumab and infliximab seems to be more effective compared with etanercept. When IBD occurs with SpA, the use of NSAIDs should be minimized, except for celecoxib, and infliximab or adalimumab are preferred to etanercept. The incidence of atherosclerotic events or SpA-specific cardiac manifestations may be decreased by cardiovascular risk management or effective antirheumatic treatment. Overall it is important to realize that extra-articular manifestations frequently occur in patients with SpA and should be taken into account in the choice of treatment.
doi:10.1177/1759720X12458372
PMCID: PMC3512172  PMID: 23227118
Ankylosing spondylitis; anterior uveitis; arthritis; cardiac manifestations; enthesitis; IBD; psoriasis; spondyloarthritis
24.  Autoreactive Memory CD4+ T Lymphocytes that mediate Chronic Uveitis Reside in the Bone Marrow through STAT3-dependent Mechanisms 
Organ-specific autoimmune diseases are usually characterized by repeated cycles of remission and recurrent inflammation. However, where the autoreactive memory T-cells reside in-between episodes of recurrent inflammation is largely unknown. In this study, we have established a mouse model of chronic uveitis characterized by progressive photoreceptor-cell loss, retinal-degeneration, focal retinitis, retinal vasculitis, multifocal-choroiditis and choroidal neovascularization, providing for the first time a useful model for studying long-term pathological consequences of chronic inflammation of the neuroretina. We show that several months after inception of acute uveitis that autoreactive memory T-cells specific to retinal autoantigen, IRBP, relocated to bone marrow (BM). The IRBP-specific memory T-cells (IL-7RαHiLy6CHiCD4+) resided in BM in resting state but upon re-stimulation converted to IL-17-/IFN-γ-expressing effectors (IL-7RαLowLy6CLowCD4+) that mediated uveitis. We further show that T-cells from STAT3-deficient (CD4-STAT3KO) mice are defective in α4β1 and osteopontin expression; defects that correlated with inability of IRBP-specific memory CD4-STAT3KO T-cells to traffic into BM. We adoptively transferred uveitis to naïve mice using BM cells from WT mice with chronic uveitis but not BM cells from CD4-STAT3KO, providing direct evidence that memory T-cells that mediate uveitis reside in BM and that STAT3-dependent mechanism may be required for migration into and retention of memory T-cells in BM. Identifying BM as survival-niche for T-cells that cause uveitis, suggests that BM stromal cells that provide survival signals to autoreactive memory T-cells and STAT3-dependent mechanisms that mediate their relocation into BM, are attractive therapeutic targets that can be exploited to selectively deplete memory T-cells that drive chronic inflammation.
doi:10.4049/jimmunol.1004019
PMCID: PMC3304102  PMID: 21832158
25.  Interleukin-17 causes neutrophil mediated inflammation in ovalbumin-induced uveitis in DO11.10 mice 
Cytokine  2009;46(1):79-91.
T cell-mediated uveitis is strongly associated with many systemic inflammatory disorders. Th17 cells are a novel T cell subset characterized by production of interleukin (IL)-17. In this study, we used DO11.10 mice to investigate the role of IL-17 in the pathogenesis of uveitis. CD4+ T cells in DO11.10 mice are genetically engineered to react with ovalbumin (OVA). IL-17 expression was determined by real-time PCR and ELISPOT. Uveitis was induced by intravitreal injection of OVA, and ocular inflammation was evaluated by intravital microscopy. OVA challenge significantly induced IL-17 production by DO11.10 splenocytes in vitro. Next, we examined whether OVA challenge could elicit local inflammation and induce IL-17 in vivo. OVA elicited marked neutrophil-predominant inflammatory cell infiltration in the eyes. This leukocyte influx was mediated by CD4+ lymphocytes as evidenced by significant inhibition of the ocular inflammation by CD4+ depleting antibody. Compared to control mice, OVA treatment induced IL-17 expression. Moreover, anti-IL-17 antibody markedly reduced OVA-mediated ocular inflammation. Finally, the neutralization of IL-17 attenuated ocular expression of CXCL2 and CXCL5, two cytokines which are chemotactic for neutrophils. Our study suggests that IL-17 is implicated in the pathogenesis of this T cell-mediated model of uveitis in part through neutrophil chemotaxis as a downstream effect of IL-17.
doi:10.1016/j.cyto.2008.12.019
PMCID: PMC2745339  PMID: 19254849
Inflammation; Interleukin-17; Uveitis

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