Staphylococcus aureus-derived virulent phenol-soluble modulin α triggers alarmin release to drive IL-36-dependent corneal inflammation

Methicillin-resistant Staphylococcus aureus (MRSA) isolated from patients with keratitis produces substantial amounts of phenol-soluble modulin α (PSMα). However, the role of PSMα in S. aureus keratitis remains unclear. We observed that PSMα-producing and PSMα-deficient strains could infect the cornea in our experimental mouse keratitis model; however, only the PSMα-producing strain delayed epithelial wound healing and induced stromal inflammation. PSMα induced damage to the epithelium, the release of alarmins IL-1α and IL-36α, and the expression of inflammatory chemokines by resident corneal cells in the mouse corneal organ culture. The IL-36 (but not IL-1) receptor antagonist attenuated mouse keratitis induced by PSMα-containing bacterial culture supernatants, as well as by infection with PSMα-producing S. aureus, suggesting that the corneal inflammations were dependent on IL-36. Recombinant PSMα elicited IL-36-dependent corneal inflammation in mice. Thus, PSMα and the subsequently released IL-36 are critical factors triggering inflammation during S. aureus keratitis.

Aqueous-Deficient Dry Eye Exacerbates Signs and Symptoms of Allergic Conjunctivitis in Mice

Dry eye disease (DED) and allergic conjunctivitis affect a large number of patients, and many patients usually have both symptoms. We investigated the interactions between DED and allergic conjunctivitis in mice. Four experimental groups were compared: control, DED, allergy, and allergy with DED. DED was induced by removing the extraorbital lacrimal glands of the mice. Allergic conjunctivitis was induced by intraperitoneal administration of ovalbumin and antigen eye drops. The early phase reaction of the allergy was evaluated using the clinical score, scratching behavior, and vascular permeability in the conjunctiva. Epithelial barrier function was assessed by an LC-biotin assay. Tear fluid volume and corneal fluorescein staining decreased in the DED and allergy with DED groups. LC-biotin penetrated the entire epithelium of both the cornea and conjunctiva in DED mice. The clinical score of the early phase reaction was higher in allergy-induced mice than in non-allergy mice. Edema of the eyelid and conjunctiva were aggravated in mice with DED. The number of scratching episodes and leakage of Evans blue into the conjunctiva were higher in allergy-induced DED mice than in control mice. The presence of aqueous-deficient dry eye caused ocular surface epithelial damage and exacerbated allergic signs and symptoms.

Intracameral Bacteriophage Injection as Postoperative Prophylaxis for Enterococcus faecalis-Induced Endophthalmitis After Cataract Surgery in Rabbits

Purpose

Post–cataract surgery bacterial endophthalmitis is a serious postoperative complication, and Enterococcus spp.–induced endophthalmitis reportedly has a particularly poor visual prognosis. This study aimed to demonstrate the prophylactic effect of postoperative intracameral phage administration in Enterococcus faecalis–induced endophthalmitis after cataract surgery in rabbits.

Methods

Endophthalmitis was induced in rabbits by injecting E. faecalis into the anterior chamber just after lensectomy while simultaneously administering either phage phiEF24C-P2 or vehicle. Retinal function was evaluated using electroretinography. The number of viable bacteria and myeloperoxidase (MPO) activity in the eye and histopathologic examinations were analyzed 48 hours after infection.

Results

In the vehicle-treated group, retinal function at 24 hours after infection was impaired, and the number of viable bacteria and MPO activity in the eye increased 48 hours later. In the phage-administered group, retinal function was maintained; the number of viable bacteria and MPO activity were significantly suppressed. Histopathologic examinations showed disruption of the retinal layers and the presence of numerous E. faecalis in the lens capsule and vitreous cavity in vehicle-treated eyes. In contrast, retinal structures were intact, and no E. faecalis staining was observed in phage-treated eyes. No retinal dysfunction was observed in the group that received phage only without lensectomy; almost no phage was detected in the eyes after 14 days of treatment.

Conclusions

Phage administration in the anterior chamber did not cause retinal dysfunction and suppressed postoperative endophthalmitis in rabbits.

Translational Relevance

In vivo results of intracameral phage administration suggest that phages are a promising prophylactic candidate for postoperative endophthalmitis.

Promotion of conjunctival fibroblast-mediated collagen gel contraction by mast cells through up-regulation of matrix metalloproteinase release and activation

Mast cells and conjunctival fibroblasts contribute to conjunctival wound healing and allergic ocular inflammation. The number of mast cells in the conjunctiva is increased in individuals with cicatricial fibrosis-causing ocular surface diseases and after glaucoma filtering surgery, suggesting that these cells may contribute to the scarring observed after such surgery. We studied the potential mechanism of fibroblast-mast cell interaction in the healing of conjunctival wounds using a three-dimensional collagen gel culture system. We found that mast cells derived from the bone marrow of mice embedded in a collagen gel did not induce gel contraction. However, an increase in mast cells was associated with increased collagen gel contraction mediated by mouse conjunctival fibroblasts. The extent of collagen degradation was not affected by the co-culture of mast cells and conjunctival fibroblasts. Gelatin zymography disclosed that mast cells increased the amounts of both the pro form of matrix metalloproteinase (MMP)-9 and the active form of MMP-2 in supernatants of conjunctival fibroblast cultures. Furthermore, the potentiating effect of mast cells on contraction of the collagen gel through conjunctival fibroblasts was attenuated by the addition of a synthetic MMP inhibitor. Thus, current results suggest that mast cells accelerate the conjunctival fibroblast-dependent contraction of collagen gel by increasing the release as well as activation of MMPs. Therefore, the interaction between mast cells and conjunctival fibroblasts may contribute to conjunctival scar formation after glaucoma filtering surgery.

Prophylactic and Therapeutic Effects of Oral Immunotherapy on Birch Pollen-Induced Allergic Conjunctivitis in Mice with a Rice-Based Edible Vaccine Expressing a Hypoallergenic Birch Pollen Allergen

We investigated the prophylactic and therapeutic effects of the oral administration of transgenic rice seeds expressing a hypoallergenic Bet v 1 derivative of allergic birch pollen conjunctivitis in mice. Transgenic rice seed depositing a chimeric molecule called TPC7 (tree pollen chimera 7) created by DNA shuffling of Bet v 1 family sequences from birch, alder and hazel in protein bodies of endosperm was generated. BALB/c mice were sensitized to birch pollen in alum and challenged with pollen in eyedrops. They were fed TPC7 transgenic or non-transgenic (control) rice seeds for 14 d before sensitization (prophylactic protocol) or 17 d after sensitization (therapeutic protocol). The clinical score and number of conjunctival eosinophils were significantly lower in TPC7-fed mice than in the control mice based on both the prophylactic and therapeutic protocols. Serum concentration of allergen-specific IgE did not differ between TPC7-fed and control groups in either protocol. Prophylactic administration of TPC7 downregulated the production of IL-4 and IFN-γ, whereas therapeutic administration of TPC7 upregulated the production of IFN-γ by allergen-stimulated splenocytes. Prophylactic or therapeutic oral administration of transgenic rice expressing TPC7 suppressed birch pollen-induced allergic conjunctivitis in mice. Feeding transgenic rice is a potentially effective approach as an allergen-specific immunotherapy for allergic conjunctivitis.

Evaluation of offset of conjunctival hyperemia induced by a Rho-kinase inhibitor; 0.4% Ripasudil ophthalmic solution clinical trial

Glaucoma leads to irreversible blindness. Numerous anti-glaucoma eye drops have been developed. Unfortunately, many patients with glaucoma still suffer from progressive visual disorders. Recently, ripasudil hydrochloride hydrate, a selective Rho-associated protein kinase inhibitor, was launched for the treatment of glaucoma. However, adverse events, such as conjunctival hyperemia, are often noted in clinical trials using healthy subjects. Therefore, we investigated the onset, offset, and kinetic changes of conjunctival hyperemia induced by ripasudil ophthalmic solution in patients with open-angle glaucoma or ocular hypertension who had already been treated with anti-glaucoma eye drops other than ripasudil. Conjunctival hyperemia was evaluated by both clinical grading by 3 ophthalmic physicians and pixel coverage of conjunctival blood vessels determined by conjunctival hyperemia-analyzing software. Conjunctival hyperemia appeared within 10 min post-instillation in most of the participants. Clinical grade and pixel coverage increased significantly 10 min post-instillation and then decreased. In most of the participants, hyperemia resolved within 2 h. Median conjunctival hyperemia offset was 90 min. A tendency of monotonic increase was observed between clinical grade and pixel coverage. Taken altogether, hyperemia induced by ripasudil was transient in glaucoma patients who had already been treated with anti-glaucoma eye drops other than ripasudil.

In vitro and in vivo performance of epinastine hydrochloride-releasing contact lenses

A number of drug-releasing contact lenses are currently being studied to address issues inherent in eye drops as a drug delivery method. In this study, we developed epinastine hydrochloride-releasing daily soft contact lenses for treatment of allergic conjunctivitis and examined their in vitro and in vivo performance. Preformed soft contact lenses with/without ionic functional groups were soaked in a solution of epinastine hydrochloride in phosphate-buffered saline to prepare epinastine hydrochloride-releasing soft contact lenses. Among these contact lenses with different ionicities, anionic lenses demonstrated the maximum, relatively linear epinastine hydrochloride release, in vitro. The amount of epinastine hydrochloride release was directly proportional to the concentration of the epinastine hydrochloride solution used to prepare the contact lens. The epinastine hydrochloride-releasing anionic soft contact lens also demonstrated prolonged drug release and significantly greater efficacy compared with epinastine hydrochloride eye drops 12 h after treatment, in vivo. Further studies are required to determine the appropriate amount of epinastine hydrochloride to be contained in the anionic soft contact lenses.

Contributions of Interleukin-33 and TSLP in a papain-soaked contact lens-induced mouse conjunctival inflammation model

INTRODUCTION

Pathological changes of severe chronic allergic conjunctivitis are driven not only via acquired immunity but also via innate immunity. Type 2 immune response-initiating cytokines may play some roles as innate immunity-dependent components of the ocular surface inflammation. To investigate the involvement of type 2 immune response-initiating cytokines in innate immunity-dependent, papain-induced conjunctival inflammation model using IL-25-, IL-33-, and TSLP receptor (TSLPR)-knockout (KO) mice with reference to basophils and ILC2.

METHODS

Papain-soaked contact lenses (papain-CLs) were installed in the conjunctival sacs of C57BL/6-IL-25 KO, IL-33 KO, TSLPR KO, Rag2 KO, Bas-TRECK, and wild-type mice and their eyes were sampled at day 5. The eosinophil and basophil infiltration in papain-CL model was evaluated histologically and cytokine expression was examined. To clarify the roles of basophils and ILC2, basophil/ILC2-depletion experiments were carried out.

RESULTS

Papain-induced conjunctival inflammation exhibited eosinophil infiltration and upregulation of Th2 cytokine expression. Reduction of eosinophil and basophil infiltration and attenuated Th2 cytokine expression were observed in the papain-CL model using IL-33 KO and TSLPR KO mice. Depletion of basophils or ILC2s in the conjunctivae of the papain-CL model reduced eosinophil infiltration.

CONCLUSIONS

Innate immunity-driven type 2 immune responses of the ocular surface are dependent on IL-33, TSLP, basophils, and ILC2. These components may be possible therapeutic targets for refractory allergic keratoconjunctivitis.

Inhibition by the Antimicrobial Peptide LL37 of Lipopolysaccharide-Induced Innate Immune Responses in Human Corneal Fibroblasts

PURPOSE

The synthesis of cytokines and adhesion molecules by corneal fibroblasts contributes to the innate immune response to corneal infection. The effects of the antimicrobial peptide LL37 on cytokine and adhesion molecule expression induced by bacterial lipopolysaccharide (LPS) in human corneal fibroblasts were examined.

METHODS

The release of the cytokines IL-6 and IL-8 into culture supernatants and the expression of intercellular adhesion molecule (ICAM)-1 at the cell surface were measured with ELISAs and by flow cytometry. The abundance of mRNAs was quantitated by RT and real-time PCR analysis, and the phosphorylation of signaling proteins was examined by immunoblot analysis. The subcellular localization of ICAM-1 and the transcription factor nuclear factor (NF)-κB was determined by immunofluorescence analysis. Neutrophil infiltration in a mouse model of LPS-induced keratitis was evaluated by immunohistofluorescence analysis.

RESULTS

The antimicrobial peptide LL37 inhibited the up-regulation of IL-6, IL-8, and ICAM-1 both at protein and mRNA levels in corneal fibroblasts induced by LPS without affecting those elicited by TNF-α. Furthermore, LL37 attenuated the LPS-induced phosphorylation of the NF-κB inhibitor IκBα and the mitogen-activated protein kinases extracellular signal-regulated kinase, p38, and c-Jun NH2-terminal kinase, as well as the translocation of NF-κB to the nucleus in corneal fibroblasts. Lipopolysaccharide-induced keratitis in mice was also suppressed by topical application of LL37.

CONCLUSIONS

The inhibition of LPS-induced cytokine and adhesion molecule expression in human corneal fibroblasts by LL37 suggests that this peptide might promote the resolution of corneal inflammation associated with bacterial infection.

Roles of Epithelial Cell-Derived Type 2-Initiating Cytokines in Experimental Allergic Conjunctivitis

PURPOSE

To clarify the possible involvement of the type 2-initiating cytokines interleukin (IL)-25, IL-33, and thymic stromal lymphopoietin (TSLP) in the pathophysiology of allergic conjunctivitis, we evaluated ragweed (RW)-induced experimental allergic conjunctivitis (EAC) models by using IL-25 knockout (KO), IL-33 KO, and TSLP receptor (TSLPR) KO mice.

METHODS

Interleukin-25 KO, IL-33 KO, TSLPR KO, and BALB/c wild-type mice were sensitized twice with RW in alum and then challenged with RW in eye drops. Clinical scores and eosinophil infiltration were evaluated. Expression levels of serum immunoglobulin E (IgE) and cytokines in the conjunctival tissues were quantified and immunohistochemical analysis was carried out.

RESULTS

Significant reductions in clinical scores and numbers of infiltrating eosinophils were observed in the RW-EAC model using IL-33 KO mice. There were no significant differences in clinical scores and numbers of infiltrating eosinophils among IL-25KO, TSLPR KO, and wild-type mice. Serum IgE concentration was upregulated after RW challenges, and there were no differences among the mouse genotypes. Expression levels of of il4, il5, il13, and ccl5 mRNA were diminished in the conjunctivae of the RW-EAC model using IL-33 KO mice compared to those in wild-type mice. Interleukin-33 expression was upregulated as early as 1 hour after RW eye-drop challenge. The number of infiltrating basophils in the conjunctivae of the RW-EAC model using IL-33 KO mice was diminished compared to that in wild-type mice.

CONCLUSIONS

Among the type 2-initiating cytokines, IL-33 may play a major role in conjunctival inflammation in an RW-EAC model.

Prevention of allergic conjunctivitis in mice by a rice-based edible vaccine containing modified Japanese cedar pollen allergens

BACKGROUND/AIMS

To determine whether oral immunotherapy with transgenic rice seeds expressing hypoallergenic modified antigens suppresses cedar pollen-induced allergic conjunctivitis by eliciting immune tolerance in mice.

METHODS

BALB/c mice were fed once a day for 20 days with 220 mg of transgenic rice expressing modified Japanese cedar pollen allergens Cry j 1 and Cry j 2 or with non-transgenic rice seeds as a control. They were then sensitised with two intraperitoneal injections of Japanese cedar pollen in alum before challenge twice with pollen in eye drops. Twenty-four hours after the second challenge, the conjunctiva, spleen, and blood were isolated for histological analysis, cytokine production assays, and measurement of serum immunoglobulin E concentrations, respectively.

RESULTS

The numbers of eosinophils and total inflammatory cells in the conjunctiva were significantly lower in mice fed the transgenic rice than in those fed non-transgenic rice. The clinical score evaluated at 15 min after antigen challenge was also significantly lower in mice fed the transgenic rice than in those fed non-transgenic rice. The serum concentrations of both total and allergen-specific immunoglobulin E were also significantly lower in mice fed the transgenic rice. Oral vaccination with transgenic rice resulted in significant down-regulation of the allergen-induced production of interleukin (IL)-2, IL-4, IL-5, IL-12p70, interferon-γ, and IL-17A by splenocytes.

CONCLUSIONS

Oral immunotherapy with transgenic rice expressing modified Japanese cedar pollen allergens suppressed pollen-induced experimental allergic conjunctivitis in mice by eliciting immune tolerance. This novel prophylactic approach is potentially safe and effective for allergen-specific oral immunotherapy in allergic conjunctivitis.

Inhibition by rebamipide of cytokine-induced or lipopolysaccharide-induced chemokine synthesis in human corneal fibroblasts

BACKGROUND/AIMS

The dry-eye drug rebamipide has mucin secretagogue activity in and anti-inflammatory effects on corneal epithelial cells. Corneal stromal fibroblasts (transdifferentiated keratocytes) function as immune modulators in the pathogenesis of chronic ocular allergic inflammation and in innate immune responses at the ocular surface. The possible anti-inflammatory effects of rebamipide on human corneal stromal fibroblasts were examined.

METHODS

Serum-deprived cells were incubated for 1 h with rebamipide and then for various times in the additional absence or presence of cytokines or bacterial lipopolysaccharide (LPS). The release of chemokines into culture supernatants was determined with ELISAs. The intracellular abundance of chemokine mRNAs was quantitated by reverse transcription and real-time PCR analysis. Degradation of the nuclear factor κB (NFκB) inhibitor IκBα was detected by immunoblot analysis.

RESULTS

Rebamipide suppressed the release of interleukin (IL)-8 and the upregulation of IL-8 mRNA induced by tumour necrosis factor α (TNF-α) or LPS in corneal fibroblasts. It also inhibited eotaxin-1 (CCL-11) expression at the protein and mRNA levels induced by the combination of TNF-α and IL-4. In addition, rebamipide attenuated the degradation of IκBα induced by TNF-α or LPS.

CONCLUSIONS

Rebamipide inhibited the synthesis of chemokines by corneal fibroblasts in association with suppression of NFκB signalling. Rebamipide may therefore prove effective for the treatment of corneal stromal inflammation associated with allergy or bacterial infection.

Inhibition of very late antigen-4 and leukocyte function-associated antigen-1 in experimental autoimmune uveoretinitis

B10.RIII mice were immunized with interphotoreceptor retinoid binding protein peptide to induce uveitis. Mice were injected intraperitoneally with anti-very late antigen-4 (VLA-4), anti-leukocyte function-associated antigen-1 (LFA-1), or a control Ab every other day from Day 5 to Day 13 post-immunization. The eyes and spleens were harvested on Day 14 or 28. The eyes were used for histologic/cytokine mRNA expression analyses. The spleens were used for Ag-recall cytokine production assays and intracellular cytokine assays. Treatment with both Abs led to a profoundly significant reduction in severity of uveitis and cytokine mRNA expression in the eye. However, cytokine production by splenocytes was significantly upregulated. Discontinuation of Ab treatment led to an increase in uveitis severity and cytokine mRNA expression in the eye, but led to a decrease in cytokine production and intracellular IFN-γ(+) and IL-17A(+)cytokine profile by splenocytes. Thus, blockade of these molecules using specific Abs may be a therapeutic option for patients with uveitis; however, such treatment must be continued.

Detection of Antigen-Specific T Cells in Experimental Immune-Mediated Blepharoconjunctivitis in DO11.10 T Cell Receptor Transgenic Mice

Antigen (Ag)-specific T cells are thought to play a key role in pathogenesis of chronic allergic conjunctivitis (AC) such as atopic keratoconjunctivitis (AKC) and vernal keratoconjunctivitis (VKC). In order to investigate the trafficking of Ag-specific T cells in experimental immune-mediated blepharoconjunctivitis (EC), we established a novel AC model in DO11.10 T cell receptor (TcR) transgenic (Tg) mice. DO11.10 TcR-Tg mice were challenged with eye drops of whole OVA protein, OVA peptide 1-15, 321-335, or 323-339. Their eyes were histologically examined. Conventional proliferation assay was performed against each Ag. Phenotypes of infiltrating cells and kinetics of Ag-specific T cells were investigated by immunohistochemistry. Adoptive transfer of CD4(+) Ag-specific T cells from DO11.10 TcR-Tg to WT mice was performed. The distribution of KJ1-26(+) cells was investigated in recipient mice. The challenge of OVA peptide 323-339 induced infiltration of inflammatory cells in conjunctivae in a dose dependent manner, accompanied by the proliferative responses of splenocytes. Immunohistochemical analysis revealed Agspecific/ non-Ag-specific T cells, macrophages, and eosinophils in conjunctivae. Infiltration of Ag-specific T cells increased 24 hr later. Transfer of CD4(+) cells from DO11.10 TcR-Tg to WT mice induced EC depending on the number of transferred cells. Ag-specific T cells were detected in the conjunctivae and spleens of recipient mice, though its numbers were significantly smaller compared to DO11.10 TcR-Tg mice. The challenge of OVA peptide 323-339 induced EC in DO11.10 TcR-Tg mice without prior sensitization. The response was mediated by CD4(+) Ag-specific T cells. The trafficking of Ag-specific T cells in EC was clearly visualized.

Rebamipide increases barrier function and attenuates TNFα-induced barrier disruption and cytokine expression in human corneal epithelial cells

BACKGROUND

Disruption of corneal epithelial barrier function by inflammation may contribute to the development of dry eye. The effects of rebamipide, a drug used for the treatment of dry eye, on barrier function and cytokine expression in a human corneal epithelial (HCE) cell line were examined.

METHODS

Barrier function of HCE cells was evaluated by measurement of transepithelial electrical resistance (TER). The subcellular localisation of the tight junction protein zonula occludens (ZO)-1 was examined by immunofluorescence analysis. The release of cytokines was determined with ELISAs, and the intracellular abundance of cytokine mRNAs was quantitated by reverse transcription and real-time PCR analysis. Degradation of the nuclear factor-κB inhibitor IκBα was detected by immunoblot analysis.

RESULTS

Rebamipide increased TER of HCE cells in a concentration-dependent manner as well as attenuating the loss of TER and the disappearance of ZO-1 from the cell surface induced by tumour necrosis factor α (TNFα). Rebamipide also suppressed TNFα-induced expression of interleukin-6 and interleukin-8 at the mRNA and protein levels and inhibited the TNFα-induced degradation of IκBα.

CONCLUSIONS

The upregulation of barrier function and the anti-inflammatory effects of rebamipide, together with its mucin secretagogue activity, may contribute to the effectiveness of this drug for the treatment of dry eye.

Two-step differentiation of mast cells from induced pluripotent stem cells

Mast cells play important roles in the pathogenesis of allergic diseases. They are generally classified into 2 phenotypically distinct populations: connective tissue-type mast cells (CTMCs) and mucosal-type mast cells (MMCs). The number of mast cells that can be obtained from tissues is limited, making it difficult to study the function of mast cells. Here, we report the generation and characterization of CTMC-like mast cells derived from mouse induced pluripotent stem (iPS) cells. iPS cell-derived mast cells (iPSMCs) were generated by the OP9 coculture method or embryoid body formation method. The number of Safranin O-positive cells, expression levels of CD81 protein and histidine decarboxylase mRNA, and protease activities were elevated in the iPSMCs differentiated by both methods as compared with those in bone marrow-derived mast cells (BMMCs). Electron microscopic analysis revealed that iPSMCs contained more granules than BMMCs. Degranulation was induced in iPSMCs after stimulation with cationic secretagogues or vancomycin. In addition, iPSMCs had the ability to respond to stimulation with the IgE/antigen complex in vitro and in vivo. Moreover, when iPSMCs generated on OP9 cells were cocultured with Swiss 3T3 fibroblasts, protease activities as maturation index were more elevated, demonstrating that mature mast cells were differentiated from iPS cells. iPSMCs can be used as an in vitro model of CTMCs to investigate their functions.

Pseudomonas aeruginosa keratitis in mice: effects of topical bacteriophage KPP12 administration

The therapeutic effects of bacteriophage (phage) KPP12 in Pseudomonas aeruginosa keratitis were investigated in mice. Morphological analysis showed that phage KPP12 is a member of the family Myoviridae, morphotype A1, and DNA sequence analysis revealed that phage KPP12 is similar to PB1-like viruses. Analysis of the phage KPP12 genome did not identify any genes related to drug resistance, pathogenicity or lysogenicity, and so phage KPP12 may be a good candidate for therapeutic. KPP12 showed a broad host range for P. aeruginosa strains isolated from clinical ophthalmic infections. Inoculation of the scarified cornea with P. aeruginosa caused severe keratitis and eventual corneal perforation. Subsequent single-dose administration of KPP12 eye-drops significantly improved disease outcome, and preserved the structural integrity and transparency of the infected cornea. KPP12 treatment resulted in the suppression of neutrophil infiltration and greatly enhanced bacterial clearance in the infected cornea. These results indicate that bacteriophage eye-drops may be a novel adjunctive or alternative therapeutic agent for the treatment of infectious keratitis secondary to antibiotic-resistant bacteria.

Maintenance of remission with low-dose olopatadine hydrochloride for itch in well-controlled chronic urticaria

Background:

The long-term follow-up of chronic urticaria (CU) is important to ensure the adequate treatment of patients. Olopatadine hydrochloride is one of the second-generation nonsedating antihistamines.

Methods:

This study was designed to assess the optimal dose of olopatadine to suppress symptoms of chronic urticarial itch in well-controlled patients. After CU patients were treated with 10 mg olopatadine, patients having a visual analog scale (VAS) itch score of less than 20 were randomly allocated into one of three groups: 10 mg/day (n = 35), 5 mg/day (n = 30), or no medication (n = 32).

Results:

The suppressive effects of both the 5 mg and 10 mg olopatadine treatments on the VAS itch score were more significant and longer lasting over a period of 4 weeks than the no-medication treatment. Both the 5-mg group and the 10-mg group showed improved urticarial symptoms and maintained their VAS itch score within normal limits compared to the no-medication group. The differences between the 5-mg and 10-mg groups were not significant.

Conclusion:

These results demonstrate that treatment with olopatadine at a dose of 5 mg once daily is effective and safe for the management and prevention of CU symptoms for itch in well-controlled patients.

High expression of nuclear factor 90 (NF90) leads to mitochondrial degradation in skeletal and cardiac muscles

While NF90 has been known to participate in transcription, translation and microRNA biogenesis, physiological functions of this protein still remain unclear. To uncover this, we generated transgenic (Tg) mice using NF90 cDNA under the control of β-actin promoter. The NF90 Tg mice exhibited a reduction in body weight compared with wild-type mice, and a robust expression of NF90 was detected in skeletal muscle, heart and eye of the Tg mice. To evaluate the NF90 overexpression-induced physiological changes in the tissues, we performed a number of analyses including CT-analysis and hemodynamic test, revealing that the NF90 Tg mice developed skeletal muscular atrophy and heart failure. To explore causes of the abnormalities in the NF90 Tg mice, we performed histological and biochemical analyses for the skeletal and cardiac muscles of the Tg mice. Surprisingly, these analyses demonstrated that mitochondria in those muscular tissues of the Tg mice were degenerated by autophagy. To gain further insight into the cause for the mitochondrial degeneration, we identified NF90-associated factors by peptide mass fingerprinting. Of note, approximately half of the NF90-associated complexes were ribosome-related proteins. Interestingly, protein synthesis rate was significantly suppressed by high-expression of NF90. These observations suggest that NF90 would negatively regulate the function of ribosome via its interaction with the factors involved in the ribosome function. Furthermore, we found that the translations or protein stabilities of PGC-1 and NRF-1, which are critical transcription factors for expression of mitochondrial genes, were significantly depressed in the skeletal muscles of the NF90 Tg mice. Taken together, these findings suggest that the mitochondrial degeneration engaged in the skeletal muscle atrophy and the heart failure in the NF90 Tg mice may be caused by NF90-induced posttranscriptional repression of transcription factors such as PGC-1 and NRF-1 for regulating nuclear-encoded genes relevant to mitochondrial function.

Regulation of experimental autoimmune uveoretinitis by anti-delta-like ligand 4 monoclonal antibody

PURPOSE

To investigate the involvement of δ-like ligand (Dll)4 in the development of experimental autoimmune uveoretinitis (EAU) in B10.RIII mice.

METHODS

B10.RIII mice were immunized with interphotoreceptor retinoid binding protein (IRBP) peptide 161-180 in complete Freund's adjuvant together with intraperitoneal injection of Bordetella pertussis toxin. mRNA expressions of Notch receptors and their ligands in the eye were evaluated. To investigate the involvement of Dll in EAU, anti-Dll1, anti-Dll4, or control antibody (Ab) was intraperitoneally injected during both the induction and the effector phases or only the effector phase. Alternatively, mice were intraperitoneally injected with γ-secretase inhibitor (GSI) or the control vehicle during the induction phase. Fourteen days after immunization, the eyes and spleens were harvested. The eyes were used for histologic and/or cytokine mRNA expression analysis, whereas the spleens were used for flow cytometric analysis, and antigen-recall proliferation and cytokine assays.

RESULTS

Expression of Notch1, 2, 4, and Dll4 in the eye were upregulated by EAU induction. Anti-Dll4 Ab treatment during both the induction and effector phases, but not only the effector phase, significantly reduced the severity of EAU. IFN-γ, IL-12p35, IL-17A, and TGF-β mRNA expression in the eye were significantly attenuated by treatment with anti-Dll4 Ab. Splenocytes from anti-Dll4 Ab-treated mice showed significantly less proliferation and IL-17 production on antigen stimulation. Also, the severity of EAU was significantly reduced by γ-secretase inhibitor treatment during the induction phase. CONCLUSIONS; Dll4-mediated Notch signaling during the sensitization is critical for the development of EAU. This can be a novel prophylactic target for autoimmune uveitis.

B and T lymphocyte attenuator regulates the development of antigen-induced experimental conjunctivitis

PURPOSE

To investigate the roles that B and T lymphocyte attenuator (BTLA) and herpesvirus entry mediator (HVEM) play in the development of antigen-induced experimental conjunctivitis (EC).

METHODS

BALB/c mice were immunized with ragweed (RW) in alum. Ten days later, the mice were challenged with RW in eye drops. After 24 hours, the conjunctivas, blood and spleens were collected for histological analysis, measurement of serum immunoglobulin (Ig) levels, and both flow cytometric analysis and cytokine assays, respectively. The mice were injected intraperitoneally with anti-BTLA antibody, anti-HVEM antibody or control antibody during either induction phase or effector phase.

RESULTS

Induction-phase treatment with anti-BTLA antibody but not anti-HVEM antibody significantly increased conjunctival eosinophil infiltration. Treatment with either antibody during the effector phase did not affect conjunctival eosinophil infiltration. Anti-BTLA antibody treatment during the induction phase reduced the B cell compartment and increased the CD11b-positive cell compartment in splenocytes. Additionally, anti-BTLA treatment upregulated IL-4 and IL-10 production of splenocytes stimulated by RW.

CONCLUSIONS

BTLA regulated the development of EC possibly by downregulating Th2 cytokine production and adjusting the compartments of immunocompetent cells. The regulation of EC by BTLA may be mediated by BTLA ligands other than HVEM.

Severe Hair Loss of the Scalp due to a Hair Dye Containing Para phenylenediamine

We report the case of a 41-year-old female showing severe hair loss approximately 90% after the use of a hair dye. These symptoms developed six days after the use of a hair dye containing PPD. A patch test showed a (++) reaction at 48 h to 1% PPD in petrolatum, whereas all metals and white petrolatum were negative. She was therefore diagnosed with contact dermatitis due to PPD, resulting in hair loss. The skin lesions gradually improved after starting treatment with the systemic corticosteroids. The possibility that allergic contact dermatitis from hair dyes may be responsible for telogen effluvium should always be considered in a patient with increased hair loss.

Dynamic changes of microRNAs in the eye during the development of experimental autoimmune uveoretinitis

PURPOSE

Interleukin (IL)-17-producing Th17 cells play a crucial role in the development of experimental autoimmune uveoretinitis (EAU). Recent studies revealed that the production of cytokines such as IL-17 is controlled by microRNA (miRNA). Here the authors investigated the expression of miRNA in the eye during the development of EAU.

METHODS

To induce EAU, B10.RIII mice were injected with interphotoreceptor retinoid binding protein peptide 161-180 with adjuvants. Control mice received adjuvants alone. Seven, 14, 21, or 28 days after immunization, eyes were harvested for histologic analysis, miRNA array, quantitative real-time polymerase chain reaction (qRT-PCR) for cytokines and miRNAs, and in situ hybridization for miRNAs. Expression levels of cytokines and miRNAs were compared with control mice.

RESULTS

No histologic changes were observed in eyes collected at day 7. At day 14, EAU was most severe, and thereafter retinal structure was gradually destroyed. Retinal inflammation was not observed in control mice. IL-17A and IL-17F were significantly higher in the eyes of EAU-induced mice at day 7. Array analysis followed by qRT-PCR revealed that in EAU-induced mice, miRNA-142-5p and miRNA-21 were significantly higher, whereas miRNA-182 was significantly lower. These changes could be detected 7 days after EAU induction. In situ hybridization analysis for these miRNAs confirmed qRT-PCR data.

CONCLUSIONS

Expression changes in three miRNAs could be detected in the eye before histologic EAU. Kinetic changes of these miRNAs in the eye paralleled those of IL-17. The possibility that miRNAs can affect IL-17 suggests that miRNAs in the retina regulate the development of EAU.

Adjuvants determine the contribution of basophils to antigen sensitization in vivo

PURPOSE

Basophils expressing FcɛRIα, the alpha chain of the total IgE high affinity receptor, appear to play a role in antigen (Ag) sensitization, although dendritic cells (DCs) are the principal Ag-presenting cells (APCs). To investigate whether these two types of APCs are involved differentially in Ag-sensitization when distinct types of adjuvants are utilized.

METHODS

To investigate whether basophils and DCs serve as APCs in vitro, whole splenocytes, FcɛRIα(+) basophil-depleted splenocytes, and CD11c(+) DC-depleted splenocytes from naïve DO11.10 mice were stimulated in vitro with ovalbumin (OVA) or OVA peptide 323-339 to evaluate Ag-induced proliferation. To investigate whether basophils function as APCs in vivo, BALB/c mice were actively immunized with ragweed (RW) emulsified in alum or Complete Freund's Adjuvant (CFA) followed by an RW challenge in eye drops. An anti-FcɛRIα antibody (Ab) or a control Ab was injected intraperitoneally during the sensitization phase. Twenty-four hours after the RW challenge, conjunctivas and spleens were harvested for histological analysis to evaluate conjunctival eosinophilia and cytokine production, respectively.

RESULTS

Depletion of basophils or DCs from naïve DO11.10 splenocytes significantly suppressed proliferative responses to either OVA or OVA peptide. Treatment with the anti-FcɛRIα Ab suppressed the conjunctival eosinophilia when alum, but not CFA, was utilized as the adjuvant. Similarly, the anti-FcɛRIα Ab inhibited cytokine production by splenocytes when alum was used as the adjuvant.

CONCLUSION

Adjuvants determine which APCs are utilized in Ag-sensitization.

Systemic overexpression of IFN-gamma and IL-5 exacerbates early phase reaction and conjunctival eosinophilia, respectively, in experimental allergic conjunctivitis

AIMS/BACKGROUND

To investigate how systemic overexpression of IL-4, IL-5 and IFN-gamma affects the severity of experimental conjunctivitis (EC) in mice.

METHODS

The tibialis anterior muscle of naive BALB/c mice was electroporated with IL-4, IL-5, IFN-gamma or a control gene, and then the mice blood and conjunctivas were harvested to measure the eosinophil content in these tissues. To evaluate the effects of cytokine gene electroporation on the early-phase reaction (EPR), cytokine gene-electroporated ragweed (RW)-immunised mice were intravenously injected with Evans Blue (EB) and then challenged with RW in eye-drops. Thirty minutes later, their conjunctivas were harvested to extract EB and evaluate the EPR. Additionally, 24 h after RW challenge, conjunctivas were harvested from cytokine gene-electroporated RW-immunised mice, which had not received intravenous injection of EB, to measure conjunctival eosinophilia.

RESULTS

Significantly more eosinophils were detected in the blood and conjunctivas of IL-5-electroporated mice in which EC was not induced. The intensity of the EPR was significantly greater in IFN-gamma-electroporated mice. Significantly greater eosinophil infiltration was seen in the conjunctivas of IL-5-electroporated EC-developing mice.

CONCLUSIONS

It appears that systemic IL-5 and IFN-gamma play different roles in the development of EC.

Analysis of Ag-presenting cells in the conjunctiva during the development of experimental immune-mediated blepharoconjunctivitis

PURPOSE

The aim of this study was to investigate the phenotypes of antigen (Ag) presenting cells (APCs) in the conjunctiva during the development of experimental immune-mediated blepharoconjunctivitis (EC), which serves as a model for investigation of severe types of human allergic conjunctivitis.

METHODS

Brown Norway rats treated by ovalbumin (OVA) were used in this study. To confirm the restriction of MHC class II by OVA-specific T cells, monoclonal Abs against MHC class II were added to the conventional proliferation assay. To evaluate the MHC class II expression in the conjunctiva during the development of EC, an immunohistochemical analysis, either as the single or double staining, was performed. Conjunctival fibroblast cell lines were established from naive rats and the MHC class II expression was evaluated by flow cytometric analysis. To examine the roles of costimulatory molecules, OVA-specific T cells were stimulated with anti-TcR Ab and anti-CD28 Ab and then subjected for Western blotting to evaluate the ERK phosphorylation. Finally, in vivo expression of B7 molecules was examined immunohistochemically.

RESULTS

OVA-specific T cells recognized OVA in the context of MHC class II. MHC class II was expressed in conjunctival macrophages but not in fibroblasts. EC induction was accompanied by abundant infiltration of macrophages positive for MHC class II. MHC class II was also expressed in conjunctival epithelial cells by EC induction. Stimulation from CD28 was necessary for ERK phosphorylation. B7-2, but not B7-1, was expressed in the conjunctiva.

CONCLUSION

Conjunctival macrophages may represent a major source of APCs for the induction of EC in the conjunctiva.

Interleukin-4–Mediated Infiltration of Eosinophils into the Conjunctiva and Its Suppression by Interferon-γ

PURPOSE

Interleukin (IL)-4 is a T helper (Th)2 cytokine that plays an important role in the development of allergic reactions. It has been suggested that IL-4 is responsible for the infiltration of eosinophils into the conjunctiva during the development of allergic conjunctivitis. However, it is still unclear whether IL-4 is able to induce this eosinophilic infiltration on its own. We investigated whether subconjunctival injection of IL-4 can induce eosinophils to infiltrate into the conjunctiva.

METHODS

Brown Norway rats were subconjunctivally injected with IL-4, eotaxin, or phosphate buffered saline (PBS), and the conjunctivas were harvested for histologic analysis (including immunohistochemistry) 6, 12, 18, and 24 hr later. The harvested conjunctivas were also subjected to reverse transcription-polymerase chain reaction (RT-PCR) analysis to examine chemokine expression. In a separate experiment, the effect of coadministering interferon-gamma (IFN-gamma) along with IL-4 was examined.

RESULTS

The subconjunctival injection of IL-4 induced eosinophil infiltration into the conjunctiva in a dose-dependent manner. IL-4 was as potent as eotaxin. The eosinophilic infiltration started 6 hr after the injection and persisted for up to 24 hr after the injection. Other infiltrating cell phenotypes were noted but were also observed in conjunctivas injected with PBS alone. RT-PCR analysis demonstrated that IL-4 injection did not upregulate chemokine RNA expression in the conjunctiva. Coinjection of IFN-gamma suppressed the infiltration of eosinophils into the conjunctiva induced by IL-4 injection.

CONCLUSIONS

The subconjunctival injection of IL-4 specifically induces eosinophils to infiltrate into the conjunctiva. In addition, IFN-gamma in the conjunctiva can counteract this effect of IL-4.

Dissection of Antigen-Specific Humoral and Cellular Immune Responses for the Development of Experimental Immune-Mediated Blepharoconjunctivitis in C57BL/6 Mice

PURPOSE

Allergic conjunctivitis is characterized by allergen-specific IgE in the serum and infiltration of eosinophils into the conjunctiva. However, it remains unclear whether early-phase reaction (EPR) mediated by Ag-specific IgE links to late-phase reaction (LPR) in the conjunctiva. We aimed to investigate whether LPR is mediated by either cellular or humoral immune responses.

METHODS

Experimental immune-mediated blepharoconjunctivitis (EC) was induced in C57BL/6 mice by either active immunization or passive immunization by transfer of ragweed (RW)-primed lymphocytes and RW-specific IgE, followed by RW challenge onto the conjunctiva. Transferring RW-primed lymphocytes were prepared from RW-primed splenocytes which were stimulated in vitro with RW for 3 days. Fifteen minutes after RW challenge, clinical findings were evaluated and 24 hr after challenge, the conjunctivas and sera were harvested for histologic analysis and measurement of IgE, respectively.

RESULTS

EPR was most prominent when EC was induced by transfer of RW-specific IgE. EPR was hardly detectable if EC was induced by transfer of RW-primed lymphocytes. Mild EPR was noted when EC was induced by active immunization. LPR, evaluated by infiltration of eosinophils into the conjunctiva, was most severe when EC was induced by transfer of RW-primed lymphocytes. Minimal, but definite LPR was induced when EC was induced by transfer of RW-specific IgE. Intermediate severity of LPR was induced when EC was induced by active immunization.

CONCLUSIONS

LPR in the conjunctiva is dominantly mediated by cellular immune responses, whereas EPR in the conjunctiva is putatively mediated by humoral immune responses. Importantly, LPR in the conjunctiva is inducible by Ag-specific IgE alone, although minute.

Regulatory T cells participate in 4-1BB-mediated suppression of experimental allergic conjunctivitis

BACKGROUND

We showed previously that treatment with an agonistic anti-4-1BB Ab during the induction phase of murine experimental allergic conjunctivitis (EC) suppresses the development of this model disease. It was reported that 4-1BB promotes the expansion of regulatory T cells. Here we asked whether the suppression of EC by agonistic anti-4-1BB Ab treatment is mediated by regulatory T cells.

METHODS

Neonatal BALB/c mice were thymectomized and intraperitoneally injected with anti-CD25 Ab. At 6 weeks of age, these mice were immunized with ragweed (RW) in alum. As a control, immunocompetent BALB/c mice were immunized. Ten days later, the mice were challenged with RW in eye drops and 24 h later, the conjunctivas and spleens were harvested for histological and flow-cytometric analyses, respectively. The agonistic anti-4-1BB Ab or control normal rat IgG was injected intraperitoneally during the induction phase of EC.

RESULTS

With regard to immunocompetent mice, anti-4-1BB Ab treatment significantly suppressed the severity of EC as evaluated by conjunctival eosinophil numbers. In contrast, in thymectomized and anti-CD25 Ab-treated mice in which CD4+CD25+ regulatory T cells were efficiently depleted, anti-4-1BB Ab treatment did not affect the severity of EC.

CONCLUSIONS

These results indicate that CD4+CD25+ regulatory T cells play a critical role in the suppression of EC by anti-4-1BB Ab treatment.

Activation of tumour-necrosis factor-related apoptosis-inducing ligand receptor enhances the severity of murine allergic conjunctivitis

BACKGROUND/AIMS

Tumour-necrosis-factor-related apoptosis-inducing ligand (TRAIL) plays a role in the development of allergic asthma. The study aimed to determine whether TRAIL also participates in the development of experimental allergic conjunctivitis (EC), another allergic disease model.

METHODS

EC was induced in BALB/c mice by active immunisation with ragweed (RW) followed by RW challenge. To investigate whether TRAIL in the conjunctiva plays a role in the development of EC, conjunctival TRAIL expression in EC-developing mice was evaluated by immunohistochemistry. Additionally, the effect of subconjunctival injection of recombinant TRAIL on conjunctival inflammation was examined. To investigate whether TRAIL expressed in systemic immunocompetent cells plays a role in the development of EC, anti-TRAIL blocking Ab or anti-TRAIL receptor agonistic Ab was intraperitoneally injected into EC-developing mice, and conjunctival eosinophil infiltration was evaluated.

RESULTS

Conjunctival TRAIL expression was not increased by EC induction. Moreover, subconjunctival injection of TRAIL protein in naive mice did not induce conjunctival inflammation. Thus, TRAIL in the conjunctiva is less likely to participate in the development of EC. Systemic treatment with anti-TRAIL blocking Ab in EC-developing mice did not affect the severity of EC. However, systemic treatment during the induction phase of EC with an agonistic Ab for the TRAIL receptor significantly augmented the severity of EC and increased Ag-recall splenocyte IFN-gamma production in vitro.

CONCLUSIONS

These results indicate that TRAIL receptor-expressing cells in lymphoid organ participate in the development of EC.

Depletion of thymus-derived CD4+CD25+ T cells abrogates the suppressive effects of alpha-galactosylceramide treatment on experimental allergic conjunctivitis

BACKGROUND

We showed previously that alpha-galactosylceramide (alpha-GalCer) treatment elevated splenic CD4+CD25+Foxp3+ T-cell numbers and suppressed the development of experimental allergic conjunctivitis (EC). Here, we investigated whether CD4+CD25+Foxp3+ T cells mediate the suppressive effects of alpha-GalCer treatment on EC.

METHODS

To deplete CD4+CD25+Foxp3+ T cells, neonatal mice were thymectomized and intraperitoneally injected with anti-CD25 Ab. At 6 weeks of age, these mice were immunized with ragweed (RW) in aluminum hydroxide. Ten days later, the mice were challenged with RW in eye drops and 24 hours later, the conjunctivas and spleens were harvested for histological and flow cytometric analyses, respectively. alpha-GalCer or vehicle was injected 2 hours prior to RW challenge. In addition, alpha-GalCer was injected into thymus-intact EC-developing mice that had not been treated with anti-CD25 Ab.

RESULTS

alpha-GalCer treatment significantly suppressed EC in the thymus-intact mice that had not been treated with anti-CD25 Ab. In contrast, alpha-GalCer treatment of thymectomized and anti-CD25 Ab-treated mice did not affect the severity of EC or splenic CD4+CD25+Foxp3+ T-cell numbers. However, alpha-GalCer treatment did significantly increase splenic CD4+CD25+Foxp3+ T-cell numbers in thymectomized mice that had not received anti-CD25 Ab.

CONCLUSIONS

alpha-GalCer treatment during the effector phase of EC increased CD4+CD25+Foxp3+ T-cell numbers, which in turn suppressed the development of EC.

Endogenous IL-17 does not play a significant role in the development of experimental murine allergic conjunctivitis

BACKGROUND

Endogenous IL-17 is needed for the Ag sensitization that results in murine allergic asthma, a Th2-mediated disease. Here, we aimed to investigate the role IL-17 plays in the development of murine experimental allergic conjunctivitis (EC) which is also a Th2-mediated disease.

METHODS

To induce EC, wild-type (WT) and IL-17-deficient (IL-17 KO) mice on the BALB/c and C57BL/6 backgrounds were immunized with ragweed (RW) in alum and challenged with RW in eye drops. Alternatively, EC was induced by adoptively transferring RW-primed splenocytes followed by challenge with RW-containing eye drops. Twenty-four hours after the RW challenge, the conjunctivas and spleens were harvested for histological analyses and cytokine assays, respectively.

RESULTS

The WT and IL-17 KO mice on both backgrounds did not differ in terms of the severity of actively induced EC, as evaluated by the conjunctival eosinophil infiltration. They also did not differ with regard to the phenotypes of the inflammatory cells infiltrating the conjunctivas, although primed IL-17 KO splenocytes stimulated in vitro with RW extract did produce significantly higher amounts of IL-4, IL-13 and IFN-gamma than WT splenocytes. Reciprocal adoptive transfer experiments also demonstrated that the IL-17 from both the donor splenocytes and the recipient mice is not involved in the development of EC.

CONCLUSIONS

Endogenous IL-17 does not appear to play a significant role in the development of EC.

Cyclosporin A inhibits eosinophilic infiltration into the conjunctiva mediated by type IV allergic reactions

BACKGROUND

Eosinophils are important effector cells in severe allergic conjunctivitis such as vernal keratoconjunctivitis. Infiltration of eosinophils into the conjunctiva is mediated by type I and type IV allergic reactions. Cyclosporin A (CsA) eye drops are administered therapeutically for severe allergic conjunctivitis, but the mechanism by which CsA acts, that is, by inhibiting type I, type IV or both types of allergic reactions, is not known. We investigated whether CsA eye drops inhibit type I, type IV or both types of allergic reactions in the conjunctiva.

METHODS

Experimental immune-mediated blepharoconjunctivitis (EC) was induced in BALB/c mice by either active immunization or passive immunization by transfer of ragweed (RW)-primed splenocytes and RW-specific IgE, followed by RW challenge to the conjunctiva. These mice were treated in eye drops with vehicle, 0.1% CsA, 0.5% CsA or 0.1% betamethasone five times (1 and 2 h before RW challenge and 1, 2 and 3 h after RW challenge). Twenty-four hours after the challenge, the conjunctivas were harvested for histological analysis to evaluate eosinophilic infiltration. To evaluate effects of CsA eye drops on systemic immune responses, sera and spleens were collected from actively immunized mice at the time of sacrifice to examine serum IgE levels and cellular immune responses, respectively.

RESULTS

CsA eye drops significantly inhibited eosinophilic infiltration into the conjunctiva in actively immunized EC-developing mice compared with vehicle-treated mice. The CsA-induced inhibition was similar to inhibition induced by 0.1% betamethasone. Serum IgE levels and splenocyte responses in CsA-treated mice were equivalent to those in vehicle-treated mice. Betamethasone treatment inhibited eosinophilic infiltration into the conjunctiva induced by both splenocyte transfer and IgE transfer, while CsA treatment inhibited infiltration induced by splenocyte transfer.

CONCLUSIONS

CsA eye drops inhibited eosinophilic infiltration into the conjunctiva without affecting systemic immune responses. CsA predominantly inhibits eosinophilic infiltration by interfering with the type IV allergic reaction in the conjunctiva.

Epigenetic inactivation of the candidate tumor suppressor gene HOXB13 in human renal cell carcinoma

Epigenetic alterations like DNA methylation and the resulting inactivation of cancer-related genes often contribute to the development of various cancers. To identify the genes that are silenced by aberrant methylation in renal cell carcinoma (RCC), we subjected two RCC lines to methylated CpG island amplification/representational difference analysis. This identified 27 CpG islands. Combined bisulfite restriction analysis of these CpG islands in primary RCC cases revealed that four were methylated in a tumor-specific manner. One of these was identified as the human homeo-box gene B13 (HOXB13) gene, but the remaining three CpG islands were not associated with known genes. The methylation frequencies of HOXB13 in primary RCC samples and lines were 30 and 73%, respectively. The methylation status of HOXB13 correlated with the loss of its expression both in RCC lines and primary tumors, and methyltransferase inhibitor treatment induced the recovery of its expression. Exogenous expression of HOXB13 in RCC cells that lacked endogenous HOXB13 expression suppressed colony formation and induced apoptotic features. Furthermore, HOXB13 methylation correlated positively with tumor grade and microvessel invasion. These results suggest that HOXB13 is a novel candidate tumor suppressor gene in RCC and that its inactivation may play an important role in both RCC tumorigenesis and progression.

Role of VLA-4 in the development of allergic conjunctivitis in mice

PURPOSE

The severity of allergic conjunctivitis (AC) correlates with the degree of eosinophil infiltration into the conjunctiva, which is believed to be mediated by chemokines and adhesion molecules. The adhesion molecule very late antigen (VLA)-4 and its ligand, vascular cell adhesion molecule (VCAM)-1, are known to play important roles in eosinophil infiltration. However, the expression and function of VLA-4 in AC have not been investigated in detail. We sought to characterize VLA-4-expressing cells in the conjunctivas of mice that are developing experimental AC (EC) and to determine whether the interaction between VLA-4 and VCAM-1 is needed for the infiltration of eosinophils into the conjunctiva in AC.

METHODS

EC was induced in Balb/c mice by active immunization with ragweed (RW) or adoptive transfer of RW-primed splenocytes, followed by RW challenge. Twenty-four hours after RW challenge, the conjunctivas were harvested. The conjunctivas from naive mice or mice developing EC were evaluated for VLA-4 and VCAM-1 expression by immunohistochemistry and immunofluorescent analyses. To investigate whether the interaction between VLA-4 and VCAM-1 is needed for the genesis of AC, mice developing EC were treated with anti-VLA-4 or anti-VCAM-1 antibodies two h before and after RW challenge. As a control, EC-developing mice were treated with normal rat IgG. Twenty-four hours after RW challenge, the conjunctivas were harvested for histological analysis.

RESULTS

Upon induction of EC, VLA-4-expressing cells infiltrated the conjunctiva but the constitutive VCAM-1 expression around conjunctival vessels was not augmented. Immunofluorescent analyses demonstrated that most of the T cells infiltrating the conjunctiva expressed VLA-4 but only half of the infiltrating eosinophils expressed it. Treatment with both anti-VLA-4 and anti-VCAM-1 antibodies significantly suppressed the infiltration of eosinophils into the conjunctiva that was induced by either active immunization or splenocyte transfer.

CONCLUSIONS

These results confirm that VLA-4-expressing cells infiltrate the conjunctiva and that the interaction between VLA-4 and VCAM-1 is needed for the development of EC.

Roles of OX40 in the development of murine experimental allergic conjunctivitis: exacerbation and attenuation by stimulation and blocking of OX40

PURPOSE

To investigate the roles of interaction between OX40 and OX40 ligand (OX40L) in the development of experimental allergic conjunctivitis (EC) in mice.

METHODS

BALB/c mice actively immunized with short ragweed pollen (RW) were intraperitoneally injected on days 0, 2, 4, 6, and 8 with agonistic anti-OX40 Ab, blocking anti-OX40L Ab, or normal rat (nr)IgG. On day 10, the mice were challenged with RW in eye drops, and 24 hours later their conjunctivas, spleens, and blood were harvested for analyses. For examination of the effects of the Abs during the late induction (or effector) phase, actively immunized mice were treated with the Abs just before or at the same time as the challenge. In addition, splenocytes from RW-primed mice were transferred into syngeneic naïve mice, and the recipients were treated with Abs twice (on days 2 and 4). On day 4, the mice were challenged with RW and evaluated.

RESULTS

When the treatments were performed during the induction phase, anti-OX40 Ab treatment significantly increased clinical EC and eosinophil infiltration into the conjunctiva, whereas anti-OX40L Ab treatment significantly reduced eosinophil infiltration. Compared with splenocytes from nrIgG-treated mice, splenocytes from anti-OX40 Ab-treated mice proliferated vigorously against RW and produced significantly higher amounts of IL-2, -4, and -5 by RW stimulation but a significantly lesser amount of IFN-gamma after Con A stimulation. In contrast, splenocytes from anti-OX40L Ab-treated mice produced significantly less IL-5 with RW stimulation and IL-2 and IL-5 with Con A stimulation, whereas significantly more IFN-gamma was induced by Con A stimulation. Treatment with anti-OX40 and anti-OX40L Abs during the late induction or effector phase of EC did not affect eosinophil infiltration.

CONCLUSIONS

Blocking of the interaction between OX40 and OX40L in vivo inhibits the development of EC. In contrast, forced stimulation of OX40 in vivo significantly exacerbates EC by activating T cells, especially Th2 cells. These effects were noted only in the induction phase of EC, suggesting that the interaction between OX40 and OX40L is important in the generation of Th2 immune responses in the development of EC.

Genetic background determines susceptibility to experimental immune-mediated blepharoconjunctivitis: Comparison of Balb/c and C57BL/6 mice

Balb/c and C57BL/6 mice have been reported to be biased towards Th2 and Th1 immune responses, respectively. We investigated which strain is more susceptible to the development of experimental immune-mediated blepharoconjunctivitis (EC), which is predominantly mediated by Th2 immune responses. EC was induced by three different methods in Balb/c and C57BL/6 mice using ragweed (RW) as the antigen. The mice were thus either actively immunized with RW, passively immunized by transfer of RW-primed T cells, or passively immunized by transfer of RW-specific IgE, followed by RW challenge in eye drops. Twenty-four hours after the challenge, conjunctivas, sera and spleens were harvested for histological analysis, measurement of serum IgE and assessment of cellular immune responses, respectively. The responses of the Balb/c and C57BL/6 mice were compared. In addition, to assess the involvement of IFN-gamma in the development of EC in the two strains, IFN-gamma knockout (GKO) mice of the two strains were actively immunized and evaluated as above. Regardless of the method of induction, EC, as determined by the degree of eosinophil infiltration into the conjunctiva, was more severe in Balb/c mice than in C57BL/6 mice. Moreover, more IgE was produced by actively immunized Balb/c mice than C57BL/6 mice and RW-primed splenocytes from Balb/c mice produced more IL-4 but less IFN-gamma than those from C57BL/6 mice. EC could be induced in the GKO mice of both strains. However, when their EC was compared to that in WT mice, significantly less infiltration of eosinophils was noted in the Balb/c GKO mice. Taken together, Balb/c mice are more susceptible to EC than C57BL/6 mice and this higher susceptibility might be related to the Th2 immune response bias of Balb/c mice. Furthermore, the involvement of endogenous IFN-gamma in the development of EC in these two strains differs.

Engagement of 4-1BB inhibits the development of experimental allergic conjunctivitis in mice

The 4-1BB receptor acts as a costimulator in CD8(+) T cell activation. Agonistic stimulation through this molecule by treatment with anti-4-1BB Abs has been demonstrated to inhibit various experimentally induced diseases in animals. However, the effect of anti-4-1BB Abs on experimental allergic diseases has not been reported. We investigated the effect of anti-4-1BB Abs on the development and progression of experimental allergic conjunctivitis in mice. To examine the effects of Abs during the induction or effector phase, actively immunized mice or passively immunized mice by splenocyte transfer were treated with agonistic anti-4-1BB Abs, blocking anti-4-1BB ligand Abs, or normal rat IgG. Eosinophil infiltration into the conjunctiva was significantly reduced in wild-type mice by the anti-4-1BB Ab treatment during either induction or effector phase. Th2 cytokine production by splenocytes and total serum IgE were significantly reduced by the anti-4-1BB Ab treatment, while IFN-gamma production was increased. The anti-4-1BB Ab treatment induced a relative increase of CD8-positive cell numbers in the spleens. Moreover, inhibition of eosinophil infiltration by the treatment with anti-4-1BB Abs was also noted in actively immunized IFN-gamma knockout mice. Taken altogether, in vivo treatment with agonistic anti-4-1BB Abs in either induction or effector phase inhibits the development of experimental allergic conjunctivitis, and this inhibition is likely to be mediated by suppression of Th2 immune responses rather than up-regulation of IFN-gamma.

The interaction between ICOS and B7RP-1 is not required for the development of experimental murine allergic conjunctivitis

It is still unclear whether the interaction between inducible costimulator (ICOS) and its ligand, B7 related protein (B7RP)-1, is important for the development of allergic diseases. We investigated whether blocking the ICOS/B7RP-1 interaction affects the development of murine experimental allergic conjunctivitis (EC). EC was induced in Balb/c mice either by active immunization of ragweed (RW) or by transferring RW-primed splenocytes, followed by challenge with RW-containing eye drops. The mice were treated with anti-B7RP-1 antibody (Ab) or normal rat immunoglobulin G (IgG) during either the induction or effector phase. Regardless of the induction method or when the animals were treated, eosinophil infiltration into the conjunctiva was not affected by the anti-B7RP-1 Ab treatment. Splenocyte responses were not largely affected by this treatment. However, serum Ig levels were significantly reduced. These data suggest that blocking the ICOS/B7RP-1 in allergic diseases may not always be therapeutic.

TLR2 agonist ameliorates murine experimental allergic conjunctivitis by inducing CD4 positive T-cell apoptosis rather than by affecting the Th1/Th2 balance

Innate immune responses that operate through Toll-like receptors (TLRs) are actively involved in the development of diseases predominantly mediated by adaptive immune responses. This is true also for allergic disease, as TLRs have been found to be involved in the development of allergic airway inflammation. We investigated whether stimulating TLR2 also abrogates murine allergic conjunctivitis by upregulating Th1 responses. We found that treating mice during the efferent phase with the TLR2 agonist Pam3CSK4 significantly suppressed eosinophil infiltration into the conjunctiva. However, Pam3CSK4 treatment inhibited both the Th1 and Th2 responses in the mice, and also suppressed eosinophil infiltration in IFN-gamma knockout mice. Flow cytometric analysis demonstrated that Pam3CSK4 treatment significantly elevated the numbers of annexin V-positive splenocytes, especially CD4 positive T cells. Thus, the stimulation of TLR2 during the efferent phase of murine allergic conjunctivitis suppresses eosinophil infiltration by inducing CD4 positive T-cell apoptosis rather than upregulating Th1 responses.

The immunization protocol determines whether endogenous interferon-γ suppresses the infiltration of eosinophils into the conjunctiva

BACKGROUND

Studies with interferon-gamma knockout (GKO) mice showed that endogenous IFN-gamma suppresses the infiltration of inflammatory cells into the conjunctiva. To examine whether this phenomenon is universally true, we induced conjunctival inflammation by four different immunization protocols.

METHODS

Both wild type (WT) and GKO mice (C57BL/6 background) were immunized with ragweed (RW) in aluminum hydroxide (alum). Two different immunization protocols were used: either the emulsion was injected into only the left hind footpad or it was also injected into the tail base (50 microg RW in 2mg alum per injection site). In addition, to compare the effects of the immunization dose of RW and the immunization site, 100 microg RW in 2mg alum was injected into only the left hind footpad and 25 microg RW in 2mg alum per injection site was injected into both the left hind footpad and the tail base. Ten days later, the mice were challenged with 2mg RW in 10 microl PBS. Twenty-four hours later, the conjunctivas were analyzed histologically, and the cellular and humoral immune responses in the spleens and sera were determined, respectively.

RESULTS

Similar to a previous report, GKO mice showed significant eosinophilic infiltration into the conjunctiva after the footpad only injection of 50 microg RW. However, injection of 50 microg RW per injection site into the footpad plus the tail base resulted in comparable levels of eosinophilic infiltration in WT and GKO mice. On the contrary, either immunization of 100 microg RW in 2mg alum into only the left hind footpad or that of 25 microg RW in 2mg alum into both the left hind footpad and the tail base induced significant infiltration of eosinophils into the conjunctiva of GKO mice, compared to WT mice.

CONCLUSIONS

These results show that the immunization protocol employed has a marked effect on the severity of eosinophilic infiltration. These observations indicate that in interpreting experimental results in the study of EC, the immunization protocol employed must be considered.

Inflammatory reaction following cataract surgery and implantation of acrylic intraocular lens in rabbits with endotoxin-induced uveitis

PURPOSE

To investigate whether inflammatory responses are more severe in uveitic eyes than nonuveitic eyes when acrylic intraocular lens (IOL) is implanted after cataract surgery.

METHODS

Clear lens removal (phacoemulsification and aspiration) was conducted and the hydrophobic acrylic IOL (AR40e, AMO) was implanted in adult albino rabbits. Just after the operation, rabbits were divided into two groups. One group (nine rabbits) received intravitreal injection of lipopolysaccharide (LPS, 200 ng/10 microl) into both eyes to induce endotoxin-induced uveitis (EIU) and the other group (nine rabbits) received intravitreal injection of phosphate-buffered saline (PBS, 10 microl) into both eyes as the control. Aqueous humour (AH) and IOLs were harvested 1, 3 , and 7 days after the intravitreal injection. The infiltrating cell number in AH was counted and the protein concentration of AH was measured. IOLs were evaluated morphologically.

RESULTS

At 1 day after intravitreal injection, both the infiltrating cell number in AH and protein concentration of AH were significantly higher in the LPS-injected group than in the PBS-injected group. Similarly, more inflammatory cells attached to the surfaces of the IOLs in the LPS-injected group. However, 7 days later, inflammatory reactions subsided and no clear differences in any of the parameters examined were observed between the two groups.

CONCLUSIONS

At 7 days after the operation, inflammatory reactions in eyes implanted with the hydrophobic acrylic IOLs were similar in uveitic eyes and nonuveitic eyes. The data suggest that the hydrophobic acrylic IOLs may be suitable for patients with uveitis.

Mice lacking the IFN-gamma receptor or fyn develop severe experimental autoimmune uveoretinitis characterized by different immune responses

Endogenous interferon (IFN)-gamma negatively regulates experimental autoimmune uveoretinitis (EAU), a Th1-mediated disease. Although it is well known that IFN-gamma exerts its effects by binding to the IFN-gamma receptor (IFN-gammaR), the role that IFN-gammaR plays in the development of EAU has not been investigated. Fyn has been reported to inhibit Th2 differentiation. We aimed to investigate how endogenous IFN-gammaR and fyn, which influence Th1/Th2 differentiation, participate in the development of EAU. Sex-matched 6- to 10-week-old C57BL/6 wild-type (WT), IFN-gammaR knockout (GRKO) and fyn knockout (fyn KO) mice were compared. Mice were immunized subcutaneously with human interphotoreceptor retinoid-binding protein peptide 1-20 emulsified in Freund's complete adjuvant together with an intraperitoneal injection of Bordetella pertussis toxin. Three weeks later, mice were sacrificed, and their eyes and spleens were harvested for histopathologic analyses and examination of cellular immune responses, respectively. Cellular immune responses were evaluated by measuring the proliferative responses and cytokine production [interleukin (IL)-4, IL-5, IL-6, IL-13, IFN-gamma and tumor necrosis factor (TNF)-alpha] of splenocytes. The incidence of EAU was 40.0% in WT mice, 59.3% in GRKO mice and 78.6% in fyn KO mice. The average EAU score was 0.294 in WT mice, 0.917 in GRKO mice and 1.063 in fyn KO mice. Upon EAU induction, significant infiltration of eosinophils into the eyes was observed in GRKO and fyn KO mice compared to WT mice. Splenocytes from GRKO mice proliferated against the antigen and a mitogen more vigorously than those from WT and fyn KO mice. Stimulation of splenocytes with the antigen induced a higher production of IL-4, IL-6, IL-13 and IFN-gamma in GRKO mice compared to WT and fyn KO mice. In contrast, IL-5 and TNF-alpha were most abundantly produced by splenocytes from fyn KO mice compared to WT and GRKO mice. The incidence and mean severity of EAU were significantly higher in GRKO and fyn KO mice than in WT mice, suggesting that endogenous IFN-gammaR and fyn negatively regulate the development of EAU. The different cytokine production patterns by the GRKO and fyn KO mice indicate that the negative regulatory mechanism mediated by IFN-gammaR and fyn may differ.

Systemic interferon-gamma suppresses the development of endotoxin-induced uveitis in mice

PURPOSE

It has been shown that interferon (IFN)-gamma is involved in the development of endotoxin-induced uveitis (EIU), but its exact role is unclear. We aimed to elucidate the role that endogenous systemic IFN-gamma plays in EIU pathogenesis.

METHODS

EIU was induced in wild-type (WT) or IFN-gamma knockout (GKO) mice on the C57BL/6 background by injecting Salmonella typhimurium endotoxin into a hind footpad. Twenty-four hours later, the eyes were harvested for histological analysis, and the serum was collected for cytokine ELISAs. WT and GKO mice were also intraperitoneally injected with 1 microg of recombinant murine IFN-gamma (rmIFN-gamma) just after and 6 h after EIU induction, and their eyes and sera were evaluated 24 h after EIU induction, as above.

RESULTS

The GKO mice had significantly more severe EIU as determined by the number of ocular infiltrating cells and lower serum IL-6 levels after EIU induction compared to WT mice. The injection of rmIFN-gamma suppressed the severity of EIU and increased the serum IL-6 levels in both the WT and GKO mice.

CONCLUSIONS

Endogenous IFN-gamma suppresses EIU pathogenesis. In addition, the systemic administration of IFN-gamma suppresses EIU. The suppressive mechanism involved is unclear but may relate to the production of IL-6.

Suppression of macrophage infiltration into the conjunctiva by clodronate liposomes in experimental immune-mediated blepharoconjunctivitis

Macrophages infiltrate the conjunctiva in severe cases of allergic conjunctivitis (AC) such as atopic keratoconjunctivitis (AKC). We established experimental immune-mediated blepharoconjunctivitis (EC) in Brown Norway (BN) rats as a model for severe types of AC. We investigated whether macrophage infiltration in the conjunctiva in this EC model is inhibited by clodronate liposomes (CL2MDP-lip). The numbers of ED1-positive but not ED2-positive macrophages in the conjunctivas were increased by the induction of EC. Subconjunctival injection of CL2MDP-lip decreased the number of ED2-positive but not ED1-positive macrophages in the conjunctivas of naive rats. CL2MDP-lip did not affect macrophages in the spleen. Subconjunctival injection of CL2MDP-lip into EC-developing BN rats decreased the number of ED2-positive macrophages at all the time points. ED1-positive cell infiltration was inhibited when treatment was administered just prior to OVA challenge. Intravenous injection of CL2MDP-lip decreased the number of ED2-positive cells in the conjunctiva. Thus, we conclude that CL2MDP-lip inhibits infiltration of macrophages into the conjunctiva within 24 h of antigen challenge.