Genetic diversity and persistent colonization of <Emphasis Type="Italic">Enterococcus faecalis</Emphasis> on ocular surfaces

Purpose

Enterococcus faecalis causes severe acute endophthalmitis and often leads to poor visual outcomes. Conjunctival bacterial cultures occasionally grow atypical bacteria including E. faecalis, which can potentially contribute to the development of postoperative endophthalmitis. However, the characteristics of these ocular E. faecalis strains are unknown. This study is the first attempt to determine the population characteristics of E. faecalis clinical isolates from eye infections and ocular commensals.

Study design

Retrospective

Methods

Twenty-eight E. faecalis ocular isolates were collected from 23 patients at 3 referring hospitals. The multilocus sequence typing (MLST) data were analyzed using the eBURST program. Phenotypes of cytolysin and gelatinase, antibiotic susceptibility, and mutations of the quinolone resistance-determining regions (QRDRs) of gyrA and parC were also examined. Pulsed-field gel electrophoresis (PFGE) was performed for strains from the same patients.

Results

PFGE revealed that 3 patients retained identical strains for 10 months to 2 and a half years. MLST identified 12 sequence types (STs), which were clustered into 3 clonal complexes (CCs) and 8 singletons, with ST179 the largest. Thirteen of the 23 isolates (56.5%) belonged to CC58, CC8, or CC2, which have previously been reported to be major CCs. Six of the 23 strains (26.0%) exhibited high-level quinolone resistance derived from mutations of the QRDRs in both gyrA and parC.

Conclusions

The sequence types of E. faecalis ocular isolates were divergent, with no eye-specific lineages observed. Persistent colonization of E. faecalis on the ocular surface was demonstrated in patients with chronic ocular surface diseases.

     

Mutation c. 1142 del G in the <Emphasis Type="Italic">PRPF31</Emphasis> Gene in a Family with Autosomal Dominant Retinitis Pigmentosa (RP11) and Its Implications

Purpose

To identify a mutation in the PRPF31 gene in a family (Family K) with autosomal dominant retinitis pigmentosa (adRP) linked to 19q13.4 (RP11) and to find the frequency of mutations in the PRPF31 gene among Japanese families with adRP.

Methods

Genomic DNA specimens were prepared from five symptomatic and two asymptomatic members of Family K and an additional 39 patients of 39 unrelated families with adRP. Coding regions of the PRPF31 gene were amplified by polymerase chain reaction. The amplicons were analyzed by a direct sequencing method.

Results

All seven family members had a heterozygous c.1142delG mutation in the PRPF31 gene, which was identical to the mutation previously reported in a different Japanese family. No other mutation was found in the PRPF31 gene among the 39 additional patients with adRP.

Conclusion

Although the frequency of mutations in the PRPF31 gene is about 2.5% in Japanese families with adRP, it is possible that c.1142delG is a common mutation among Japanese patients with adRP associated with mutations in the PRPF31 gene.?Jpn J Ophthalmol 2007;51:45–48 © Japanese Ophthalmological Society 2007

     

<Emphasis Type="Italic">MTHFR</Emphasis> and <Emphasis Type="Italic">MTHFD1</Emphasis> gene polymorphisms are not associated with pseudoexfoliation syndrome in South Indian population

Purpose

Pseudoexfoliation syndrome (PEX) is a late onset disorder of extracellular matrix turnover, associated systemically with cardiovascular and cerebrovascular disease. To evaluate the suggested association of polymorphisms of homocysteine metabolism genes MTHFR (rs1801131, rs1801133) and MTHFD1 (rs8006686) with PEX.

Methods

A case–control association study was undertaken, comprising a total of 1472 individuals including 860 unrelated PEX cases and 612 ethnic-matched cataract controls (CC). All the study subjects were genotyped for three SNPs using the TaqMan allelic discrimination assay. Association and statistical analysis were performed with PLINK 1.07 and STATA 11.1.

Results

Among the three SNPs genotyped, MTHFR polymorphisms did not exhibit significant association with PEX (rs1801131; p = 0.549, rs1801133; p = 0.408). The intronic SNP rs8006686 showed nearly significant association (p = 0.069), and however did not remain significant after Bonferroni correction.

Conclusion

Our study suggests no significant genetic association of MTHFR (rs1801131, rs1801133) and MTHFD1 (rs8006686) polymorphisms in South Indian PEX patients.

     

Long-term clinical course of 2 Japanese patients with <Emphasis Type="Italic">PRPF31</Emphasis>-related retinitis pigmentosa

Purpose

To assess the long-term clinical course of 2 patients with PRPF31-related retinitis pigmentosa (RP).

Patients and methods

We clinically examined 2 unrelated patients with RP and collected peripheral blood samples from them. Ophthalmic examinations, including best-corrected visual acuity measurements, Goldmann perimetry, full-field electroretinography, fundus autofluorescence imaging, and optical coherence tomography, were also performed. The visual acuity and visual field were continuously monitored. To identify the causative mutations, 74 genes known to cause RP or Leber congenital amaurosis were examined via targeted next-generation sequencing.

Results

The clinical courses of both patients were similar. The onset of nyctalopia occurred in the first decade. Fundus examination showed typical RP. Although the patients’ visual acuity was relatively preserved even into the fourth decade, the visual field area exhibited rapid deterioration in the mid-teens, with severe concentric constriction in the third decade. Mutation analysis revealed PRPF31 mutations as the cause for autosomal dominant RP in both patients.

Conclusions

To the best of our knowledge, few reports of long-term observations pertaining to patients with PRPF31-related RP have been published. The findings reported herein, especially those relating to the progressive degeneration of the visual field, may ultimately play a role in the provision of high-quality counseling for patients with this condition.

     

A novel <Emphasis Type="Italic">C</Emphasis>x<Emphasis Type="Italic">50</Emphasis> (<Emphasis Type="Italic">GJA8</Emphasis>) p.H277Y mutation associated with autosomal dominant congenital cataract identified with targeted next-generation sequencing

Background

To unravel the molecular genetic background responsible for autosomal dominant congenital pulverulent nuclear cataracts in a four-generation Chinese family.

Methods

Family history data were collected, ophthalmological examinations were performed, and genomic DNA was extracted from peripheral blood of the family members. The candidate genes were captured and sequenced by targeted next-generation sequencing, and the results were confirmed by Sanger sequencing. The structure modelling of the protein was displayed based on Swiss-Model Server, and its possible changes in the secondary structure were predicted using Antheprot 2000 software. The chemical dissimilarity and possible functional impact of an amino acid substitution were performed with Grantham score, PolyPhen-2, and SIFT predictions. Protein distributions were assessed by confocal microscopy.

Results

A novel heterozygous c.829C?>?T transition that led to the substitution of a highly conserved histidine by tyrosine at codon 277 (p.H277Y) in the coding region of connexin50 (Cx50, GJA8) was identified. Bioinformatics analysis showed that the mutation likely altered the secondary structure of the protein by replacing the helix of the COOH-terminal portion with a turn. The mutation was predicted to be moderately conservative by Grantham score and to be deleterious by both PolyPhen-2 and SIFT with consistent results. In addition, when expressed in COS1 cells, the mutation led to protein accumulation and caused changes in Cx?50 protein localization pattern.

Conclusions

This is a novel missense mutation [c.829C?>?T, (p.H277Y)] identified in exon 2 of Cx50. Our findings expand the spectrum of Cx50 mutations that are associated with autosomal dominant congenital pulverulent nuclear cataract.

     

Heterozygous deletion of the <Emphasis Type="Italic">OPA1</Emphasis> gene in patients with dominant optic atrophy

Purpose

Several OPA1 variants cause dominant optic atrophy (DOA), the most common hereditary optic atrophy. Here, we describe a newly discovered OPA1 deletion in 3 patients with DOA.

Methods

A female proband, her brother, and her mother underwent complete ophthalmologic examinations that included optical coherence tomography and visual field assessments using a Humphrey Field Analyzer with both standard automated perimetry (SAP) and short-wavelength automated perimetry (SWAP). Genomic DNA from each patient was examined to detect genomic rearrangements involving OPA1; the genetic analysis involved both multiplex ligation probe amplification and conventional Sanger sequencing.

Results

Each patient had temporal optic disc pallor and significant thinning of the retinal nerve fiber layer in both eyes, although there was phenotypic variability among the patients that ranged from asymptomatic to moderately decreased visual acuity. For the affected brother and mother, the mean deviation values from SAP were within the normal range, whereas those from SWAP were significantly below the normal range (P < .05). The genetic analysis identified a newly discovered heterozygous deletion that encompasses exons 9–14 and revealed a breakpoint junction that directly connects intron 8 to intron 14.

Conclusions

This newly described deletion is likely to lead to loss of function in the functionally important GTPase domain encoded by exons 9–16, and the heterozygosity suggested that haploinsufficiency caused the phenotypes. The deletion may be associated with mild DOA phenotypes ranging from asymptomatic to moderately decreased visual acuity.

     

Association between the <Emphasis Type="Italic">8</Emphasis>-<Emphasis Type="Italic">oxoguanine DNA glycosylase</Emphasis> gene Ser326Cys polymorphism and age-related cataract: a systematic review and meta-analysis

Purpose

To investigate the association between the 8-oxoguanine DNA glycosylase (OGG1) gene Ser326Cys (rs1052133) polymorphism and age-related cataract (ARC).

Methods

MEDLINE and EMBASE were searched to identify potential studies published before May 19, 2017, investigating the association between the OGG1 gene Ser326Cys polymorphism and ARC risk. The quality of eligible studies was assessed using the Newcastle–Ottawa Scale tool. The association between the OGG1 gene Ser326Cys polymorphism and ARC was analyzed using meta-analysis. Publication bias and sensitivity analyses were also performed.

Results

Six studies were included in this systematic review, and five of these studies with Hardy–Weinberg equilibrium were included in a meta-analysis. The sample size of the meta-analysis was 3716, including 1831 patients with cataract and 1885 controls. Odds ratios (ORs) were 0.67 (95% confidence interval (CI) 0.52–0.85), 0.90 (95% CI 0.54–1.51), 0.52 (95% CI 0.32–0.85) and 0.72 (95% CI 0.56–0.92) for recessive, dominant, additive and allele contrast models, respectively. Sensitivity analysis indicated that the results of the meta-analysis were robust. No publication bias was observed.

Conclusions

The OGG1 gene Ser326Cys polymorphism was associated with ARC risk.

     

Occurrence of <Emphasis Type="Italic">Demodex</Emphasis> species in patients with blepharitis and in healthy individuals: a 10-year observational study

Purpose

Two Demodex species (eyelash mites)—D. folliculorum and D brevis—are believed to be associated with human skin and eye diseases. However, the clinical significance of infection with Demodex species remains controversial.

Study design

The aim of this study was to estimate the prevalence of ocular demodicosis in patients with blepharitis as compared with the prevalence in the healthy population in Poland.

Methods

This case-control prospective study was carried out from 2007 to 2016. The enrolled patients (668) were divided into 2 groups: the study group, comprising 553 patients with blepharitis (349 women and 204 men, aged 17–88 years), and the control group, comprising 115 healthy volunteers without a history of ocular pathologies (78 women and 37 men, aged 17–88 years). A sample of 10 eyelashes was taken aseptically from each eye of the examined person and later studied under a light microscope.

Results

Demodex species were found in 62.4% (345/544) of the patients in the study group and in 24.3% (28/100) of the controls (P = .001, OR = 0.006). The overall prevalence was 55.8% (373/668) in all the examined participants. The presence of Demodex infection increased with age in both groups. No association of Demodex infection with gender was found (119/204 vs 226/349; P > .05, OR 1.086). A high mean number of mites was present more frequently in patients aged older than 50 years and in those who complained especially about itching (P < .05).

Conclusion

The prevalence of ocular demodicosis is significantly correlated with blepharitis and increases with age.

     

The association of <Emphasis Type="Italic">Helicobacter pylori</Emphasis> with choroidal and retinal nerve fiber layer thickness

Purpose

To investigate the effect of Helicobacter pylori (H. pylori) infection on choroidal thickness (CT) and retinal nerve fiber layer thickness (RNFLT).

Methods

The study included 25 patients with H. pylori infection and 25 healthy individuals as the control group. Helicobacter pylori patients were classified as the pre-treatment (Group 1; n: 25) and the post-treatment (Group 2; n: 25). RNFLT and CT were measured before and after treatment of H. pylori infection, using enhanced depth imaging (EDI) spectral-domain optical coherence tomography (Spectralis, Heidelberg Engineering, Heidelberg, Germany). The axial length and intraocular pressure were also measured.

Results

The mean subfoveal CT was 320.96 ± 29.15 μm in Group 1 and 287.48 ± 49.17 in the control group (p = 0.007), while the mean subfoveal CT did not show any difference between Group 2 and the control group (p > 0.05). No statistically significant difference was determined between the H. pylori patients and the control group in respect of RNFLT values (p > 0.05).

Conclusions

CT increases during H. pylori infection and returns to the normal range within 6 weeks of treatment. RNFLT does not show any change during H. pylori infection. The data related to the subfoveal CT may be useful in understanding the pathogenesis of central serous chorioretinopathy developing in H. pylori patients.

     

<Emphasis Type="Italic">Oestrus ovis</Emphasis> external ophtalmomyiasis: a case report in Burgundy France

Background

External ophtalmomyiasis (EOM) is a zoonosis related to the presence of Oestrus ovis larvae at the ocular level in small ruminants (i.e. ovine, caprine). In humans, EOM is a rare cosmopolitan disorder, mostly described in warm and dry rural areas in patients living close to livestock areas. In metropolitan France (excluding Corsica), EOM is an exceptional disease with less than 25 cases recorded since 1917.

Case presentation

We report a case of EOM in a 19-years old man in the last week of September 2016 in Burgundy.

Conclusion

The diagnosis of an EOM in Burgundy, a French region described as cold and humid, is surprising and could be due to a more marked climatic warming during the vegetative season in Burgundy resulting in the implantation of Diptera of the genus Oestrus sp. in this region.

     

Cytotoxic activity and degradation patterns of structural proteins by corneal isolates of <Emphasis Type="Italic">Acanthamoeba</Emphasis> spp

Background

Proteolytic enzymes secreted by trophozoites (amoebic secretome) are suggested as the main virulence factor involved in the severity of Acanthamoeba keratitis. The degradation profile of the main glycoprotein components of anterior and posterior portions of the cornea and the cytopathic effect of secretomes on endothelial cells by contact-independent mechanism were evaluated.

Methods

Trophozoites were isolated primarily from corneal tissue samples (n?=?11) and extracellular proteins were collected from axenic cell culture supernatants. The molecular weights of proteolytic enzymes were estimated by zymography. Enzymatic cleavage of laminin and fibronectin substrates by amoebic secretome was investigated and cluster analysis was applied to the proteolysis profiles. Primary cultures of endothelial cells were used in both qualitative and quantitative assays of cytophatogenicity.

Results

Differential patterns of proteolysis were observed among the Acanthamoeba secretomes that were analysed. The uniformity of laminin degradation contrasted with the diversity of the proteolysis profiles observed in the fibronectin substrate. Acanthamoeba secretome extracted from four clinical isolates was shown to be toxic when in contact with the endothelial cell monolayer (p?<?0.01). Induction of apoptosis and membrane permeability, at different percentual values, were suggested as the main mechanisms that could induce endothelial cell death when in contact with amoebic secretome.

Conclusions

Our results provide evidence that virulence factors secreted by Acanthamoeba trophozoites can be related to an increased pathogenicity pattern by an independent contact-trophozoite mechanism, through induction of endothelial cell death by apoptosis at a higher percentage than providing the lack of cell viability by the membrane-associated pore-forming toxin activity.

     

A novel mutation in the <Emphasis Type="Italic">PRPF31</Emphasis> in a North Indian adRP family with incomplete penetrance

Purpose

To identify the underlying genetic defect for non-syndromic autosomal dominant retinitis pigmentosa (adRP) with incomplete penetrance in a North Indian family.

Methods

Family history and clinical data were collected. Linkage analysis using 72 fluorescently labeled microsatellite markers flanking all the 26 candidate genes known for adRP was performed. Mutation screening in candidate gene at the mapped region was performed by bi-directional DNA sequencing.

Results

Positive two-point lod scores?>?1.0 (θ?=?0.000) suggestive of linkage were obtained with markers D19S572, D19S927 and D19S926 at 19q13.42, in the vicinity of PRPF31 gene. Mutation screening in all the 14 exonic regions and intron–exon boundaries of PRPF31 revealed a novel change, i.e. c.896G>A (p.Cys299Tyr) in exon eight. The observed change segregated in heterozygous form in all the six affected members and in three carriers, consistent with incomplete penetrance. This substitution was not observed in tested 15 unaffected members and in 200 ethnically matched controls.

Conclusion

Present study describes mapping of a locus for non-syndromic adRP with incomplete penetrance at 19q13.42 in a North Indian family and identifies a novel missense mutation (p.Cys299Tyr) in PRPF31 localized at the mapped interval. The observed substitution lies in the NOP domain of PRPF31 that exhibit RNA and protein binding surfaces and thus may interfere in the formation of spliceosome complex. Due to p.Cys299Tyr substitution hydrogen bonds are generated, which may result in conformational changes and PRPF31 protein deformity. Present findings further substantiate the role of PRPF31 in adRP with incomplete penetrance and expand the mutation spectrum of PRPF31.

     

Methicillin resistance and biofilm production of <Emphasis Type="Italic">Staphylococcus epidermidis</Emphasis> isolates from infectious and normal flora conjunctiva

Purpose

Coagulase-negative staphylococci have been reported to be the most frequent cause of bacterial postoperative endophthalmitis. Biofilm formation is the major virulence factor of Staphylococcus epidermidis and is often associated with methicillin resistance. This study aims at evaluating the presence of biofilm-producing and methicillin resistance genes (mecA) in S. epidermidis.

Methods

S. epidermidis isolated from clinically infected sites (group 1) and from normal human conjunctiva (group 2) were studied. All the isolates were tested for their ability to produce biofilm by the conventional Christensen´s method and the presence of mecA by PCR using the 22-mer oligonucleotides as primers.

Results

In total 20 isolates from group 1 and 22 from group 2 were studied. Biofilm and mecA were detected in 15 (75 %) and in 14 (70 %) in group 1 as compared to 8 (36.3 %) and 4 (18.2 %) in group 2 (p = 0.016). Simultaneously, biofilm production and presence of mecA genes were observed in 13/20 (65.0 %) in group 1, and 4/22 (18.2 %) in group 2 (p = 0.002). Multi-resistance was observed in 55 % in group 1 and 9 % in group 2 (p = 0.002); 57 % of the biofilm-producing strains was multi-resistant in contrast to none of the non-producing strains. In all multi-resistant strains, biofilm production was seen.

Conclusions

Biofilm formation capacity was widely distributed, particularly among mecA (+) S. epidermidis strains, which also displayed a high diversity of antibiotic resistance profiles.

     

Riggs-type dominant congenital stationary night blindness: ERG findings,a new <Emphasis Type="Italic">GNAT1</Emphasis> mutation and a systemic association

Purpose

To characterize the ultrastructural and functional correlates of hydroxychloroquine (HCQ)-induced subclinical bull’s eye lesion seen on near-infrared reflectance (NIR) imaging.

Methods

An asymptomatic 54-year-old male taking HCQ presented with paracentral ring-like scotoma, abnormal multifocal electroretinography (mfERG) and preserved ellipsoid zone on optical coherence tomography (OCT). Dense raster OCT was performed to create en face reflectivity maps of the interdigitation zone. Macular Integrity Assessment (MAIA) microperimetry and mfERG findings were compared with NIR imaging, en face OCT, retinal thickness profiles and wave-guiding cone density maps derived from flood-illumination adaptive optics (AO) retinal photography.

Results

The bull’s eye lesion is an oval annular zone of increased reflectivity on NIR with an outer diameter of 1450 µm. This region corresponds exactly to an area of preserved interdigitation zone reflectivity in en face OCT images and of normal cone density on AO imaging. Immediately surrounding the bull’s eye lesion is an annular zone (3°–12° eccentricity) of depressed retinal sensitivity on MAIA and reduced amplitude density on mfERG. Wave-guiding cone density at 2° temporal was 25,400 per mm². This declined rapidly to 12,900 and 1200 per mm² at 3° and 4°.

Conclusion

Multimodal imaging illustrated pathology in the area surrounding the NIR bull’s eye, characterized by reduced reflectance, wave-guiding cone density and retinal function. Further studies are required to investigate whether the bull’s eye on NIR imaging and en face OCT is prominent or consistent enough for diagnostic use.

     

Visual consequences of electronic reader use: a pilot study

Background

With the increasing prevalence of electronic readers (e-readers) for vocational and professional uses, it is important to discover if there are visual consequences in the use of these products. There are no studies in the literature quantifying the incidence or severity of eyestrain, nor are there clinical characteristics that may predispose to these symptoms with e-reader use.

Purpose

The primary objective of this pilot study was to assess the degree of eyestrain associated with e-reader use compared to traditional paper format. The secondary outcomes of this study were to assess the rate of eyestrain associated with e-reader use and identify any clinical characteristics that may be associated with the development of eyestrain.

Methods

Forty-four students were randomly assigned to study (e-reader iPAD) and control (print) groups. Participant posture, luminosity of the room, and reading distance from reading device were measured during a 1-h session for both groups. At the end of the session, questionnaires were administered to determine symptoms.

Results

Significantly higher rates of eyestrain (p = 0.008) and irritation (p = 0.011) were found among the iPAD study group as compared to the print ‘control’ group. The study group was also 4.9 times more likely to report severe eyestrain (95 % CI [1.4, 16.9]). No clinical characteristics predisposing to eyestrain could be identified.

Conclusions

These findings conclude that reading on e-readers may induce increased levels of irritation and eyestrain. Predisposing factors, etiology, and potential remedial interventions remain to be determined.

     

Comparison of visual outcomes and reading performance after bilateral implantation of multifocal intraocular lenses with bilateral monofocal intraocular lenses

Purpose

To compare the visual acuity outcomes, contrast sensitivity function (CS) and reading ability in patients with bilateral multifocal intraocular lenses and patients with bilateral monofocal lenses.

Setting

Vizyon Eye Center, Denizli, Turkey.

Design

Comparative case series.

Methods

Consecutive bilateral cataract patients having implantation of Acriva Reviol MFM 611 multifocal IOLs (Group A) or Acriva BB UD 613 monofocal IOLs (Group B) were included. Parameters analyzed 6 months postoperatively included monocular uncorrected distance (UDVA), binocular uncorrected intermediate (UIVA), binocular uncorrected near (UNVA), CS and bilateral reading performance using MN Read.

Results

The study evaluated 42 eyes in Group A and 40 eyes in Group B. There were no statistically significant differences in UDVA between two groups postoperatively (p = .39). Binocular UIVA and binocular UNVA are better in Group A (p = .00, p = .00). Under photopic and scotopic conditions, contrast sensitivity results were decreased in Group A, especially at high spatial frequencies. No statistically difference were found in reading acuity, critical print size and maximum reading speed between two groups (p = .57, p = .62, p = .22).

Conclusions

This study concludes that multifocal lenses are reliable and efficient replacements for reading glasses since they significantly improve the vision for near or intermediate distance activities.

     

Triple-A syndrome with prominent ophthalmic features and a novel mutation in the <Emphasis Type="Italic">AAAS</Emphasis>gene: a case report

Background

Triple-A syndrome (Allgrove syndrome) is an autosomal recessive disorder characterized by adrenal insufficiency, alacrima, achalasia, and – occasionally – autonomic instability. Mutations have been found in the AAAS gene on 12q13.

Case presentation

We present the case of a 12 year-old boy with classic systemic features of triple-A syndrome and several prominent ophthalmic features, including: accommodative spasm, dry eye, superficial punctate keratopathy, and pupillary hypersensitivity to dilute pilocarpine. MRI showed small lacrimal glands bilaterally. DNA sequencing of PCR-amplified fragments from the 16 exons of the AAAS gene revealed compound heterozygosity for a new, out-of-frame 5-bp deletion in exon 15, c1368-1372delGCTCA, and a previously-described nonsense mutation in exon 9, c938C>T, R286X.

Conclusions

In addition to known ophthalmic manifestations, triple-A syndrome can present with accommodative dysregulation and ocular signs of autonomic dysfunction.

     

Crucial role of P2X<Subscript>7</Subscript> receptor for effector T cell activation in experimental autoimmune uveitis

Purpose

To investigate the roles of P2X7 receptors (P2RX7) in the pathogenesis of experimental autoimmune uveoretinitis (EAU).

Study design

Experimental.

Methods

Either wild-type (P2rx7 ^+/+ ) or P2rx7-deficient (P2rx7 ^?∕? ) mice were immunized with interphotoreceptor retinoid-binding protein (IRBP) peptide 1-20. Severity of EAU was evaluated clinically and histopathologically. The induction of IRBP-specific proliferation and cytokines in draining lymph nodes was assessed by enzyme-linked immunosorbent assays (ELISA). The frequency of activation markers was examined by flow cytometry. Furthermore, inhibitory roles of systemic administration of Brilliant Blue G (BBG), an antagonist for P2RX7, in EAU were also assessed in the wild-type mice.

Results

The severity of EAU in P2rx7 ^?∕? mice was reduced as compared with that in P2rx7 ^+/+ mice, both clinically and histopathologically. IRBP-specific proliferation in P2rx7 ^?∕? on day 16 was slightly decreased compared to that in P2rx7 ^+/+ mice. The induction of IRBP-specific interferon (IFN)-γ and interleukin (IL)-17 in P2rx7 ^?∕? mice on day 16 was lower than that in P2rx7 ^+/+ mice. The up-regulation of surface expression of activation markers such as CD25, CD44, and CD69 in response to TCR stimulation in P2rx7 ^?∕? mice was decreased as compared with that in P2rx7 ^+/+ mice. Furthermore, neutralization of P2RX7 in vivo by BBG suppressed EAU clinically and histopathologically. IRBP-specific IFN-γ and IL-17 induction in BBG-treated mice was significantly lower than that in vehicle-treated mice.

Conclusion

The results suggest that P2RX7 is a novel preventative therapeutic target for uveitis as it suppresses the effector functions of both Th1 and Th17 cell responses.