Up-regulated gene expression in the conjunctival epithelium of patients with Sjögren's syndrome

The Involvement of Alarmins in the Pathogenesis of Sjögren's Syndrome

Sjögren’s syndrome (SS) is a chronic autoimmune disease that affects exocrine glands, primarily the salivary and lachrymal glands. It is characterized by lymphoplasmacytic infiltration of the glandular tissues, ultimately leading to their dysfunction and destruction. Besides classic dry eyes and dry mouth defined as sicca syndrome, patients affected by the disease also typically display symptoms such as fatigue, pain and in more than 50% of cases, systemic manifestations such as arthritis, interstitial lung involvement, neurological involvement and an increased risk of lymphoma. The pathophysiological mechanisms underlying SS still remain elusive. The crucial role of innate immunity has been advocated in recent years regarding the pathogenesis of pSS, especially in the initiation and progression toward autoimmunity. Alarmins are endogenous molecules that belong to the large family of damage associated molecular pattern (DAMP). Alarmins are rapidly released, ensuing cell injury and interacting with pattern recognition receptors (PRR) such as toll-like receptors (TLR) to recruit and activate cells of the innate immune system and to promote adaptive immunity responses. This review highlights the current knowledge of various alarmins and their role in the pathogenesis of pSS.

Investigation of the relationship between ocular sarcoidosis and dry eye

A relationship between ocular sarcoidosis (OcSar) and dry eye (DE) has previously been reported. Here we investigated the tear function in OcSar, and the other uveitis, Vogt–Koyanagi–Harada disease (VKH), to elucidate the association between OcSar and DE. This study involved 27 eyes of 27 female OcSar patients [mean age: 67.3 ± 13.5 (SD) years], 18 eyes of 18 female VKH patients (53.1 ± 14.1 years), and 17 eyes of 17 female healthy control subjects (59.7 ± 9.6 years). In all examined eyes, tear meniscus height (TMH, mm), fluorescein breakup time (FBUT, s), scoring of keratoconjunctival epithelial damage (ED), and the Schirmer 1 test (ST1, mm/5 min) were analyzed. In the OcSar patients, VKH patients, and control subjects, the respective TMH, FBUT, ED, and ST1 values (mean ± SD) were 0.26 ± 0.10, 0.24 ± 0.09, and 0.24 ± 0.08, 4.3 ± 2.5, 7.3 ± 2.9, and 6.3 ± 3.1, 1.1 ± 1.1, 0.7 ± 0.8, and 0.1 ± 0.3, and 12.9 ± 10.5, 21.5 ± 12.1, and 24.3 ± 10.5. Statistically, the ST1 values were significantly lower in the OcSar patients than in the VKH patients (P = 0.004) and control subjects (P = 0.001). ST1 findings revealed that the neural reflex arc and lacrimal gland system, which attenuate the vicious cycle between the tear film and ocular surface epithelium in DE, are significantly impaired in OcSar cases, thus indicating a possible association between OcSar and DE.

Autoimmune Epithelitis and Chronic Inflammation in Sjögren's Syndrome-Related Dry Eye Disease

Autoimmune epithelitis and chronic inflammation are one of the characteristic features of the immune pathogenesis of Sjögren’s syndrome (SS)-related dry eye disease. Autoimmune epithelitis can cause the dysfunction of the excretion of tear fluid and mucin from the lacrimal glands and conjunctival epithelia and meibum from the meibomian glands. The lacrimal gland and conjunctival epithelia express major histocompatibility complex class II or human leukocyte antigen-DR and costimulatory molecules, acting as nonprofessional antigen-presenting cells for T cell and B cell activation in SS. Ocular surface epithelium dysfunction can lead to dry eye disease in SS. Considering the mechanisms underlying SS-related dry eye disease, this review highlights autoimmune epithelitis of the ocular surface, chronic inflammation, and several other molecules in the tear film, cornea, conjunctiva, lacrimal glands, and meibomian glands that represent potential targets in the treatment of SS-related dry eye disease.

Differentially Expressed Gene Pathways in the Conjunctiva of Sjögren Syndrome Keratoconjunctivitis Sicca

Sjögren syndrome (SS) is an autoimmune condition that targets the salivary and lacrimal glands, with cardinal clinical signs of dry eye (keratoconjunctivitis sicca, KCS) and dry mouth. The conjunctiva of SS patients is often infiltrated by immune cells that participate in the induction and maintenance of local inflammation. The purpose of this study was to investigate immune-related molecular pathways activated in the conjunctiva of SS patients. Female SS patients (n=7) and controls (n=19) completed a series of oral, ocular surface exams. Symptom severity scores were evaluated using validated questionnaires (OSDI and SANDE). All patients fulfilled the ACR/EULAR criteria for SS and the criteria for KCS. Fluorescein and lissamine green dye staining evaluated tear-break-up time (TBUT), corneal and conjunctival disease, respectively. Impression cytology of the temporal bulbar conjunctiva was performed to collect cells lysed and subjected to gene expression analysis using the NanoString Immunology Panel. 53/594 differentially expressed genes (DEGs) were observed between SS and healthy controls; 49 DEGs were upregulated, and 4 were downregulated (TRAF5, TGFBI, KLRAP1, and CMKLRI). The top 10 DEGs in descending order were BST2, IFITM1, LAMP3, CXCL1, IL19, CFB, LY96, MX1, IL4R, CDKN1A. Twenty pathways had a global significance score greater or equal to 2. Spearman correlations showed that 29/49 upregulated DEGs correlated with either TBUT (inverse) or OSDI or conjunctival staining score (positive correlations). Venn diagrams identified that 26/29 DEGs correlated with TBUT, 5/26 DEGs correlated with OSDI, and 16/26 correlated with conjunctival staining scores. Five upregulated DEGs (CFB, CFI, IL1R1, IL2RG, IL4R) were uniquely negatively correlated with TBUT. These data indicate that the conjunctiva of SS patients exhibits a phenotype of immune activation, although some genes could be inhibitory. Some of the DEGs and pathways overlap with previous DEGs in salivary gland biopsies, but new DEGs were identified, and some of these correlated with symptoms and signs of dry eye. Our results indicate that gene analysis of conjunctiva imprints is a powerful tool to understand the pathogenesis of SS and develop new therapeutic targets.

Clinical Implication of Patchy Pattern Corneal Staining in Dry Eye Disease

Corneal fluorescein staining in a form that is commonly called a “patchy pattern (PP)” is sometimes seen with or without superficial punctate keratopathy (SPK) in dry-eye diseases (DEDs). Here, we investigated the differences in the clinical features of DED patients with and without PP corneal staining (PPCS). This study involved 35 DEDs with PPCS (PPCS group) and 30 DEDs with SPK and without PPCS (non-PPCS group). The tear meniscus radius (TMR, mm), spread grade (SG) of the tear-film lipid layer (i.e., SG 1–5, 1 being best), noninvasive breakup time (NIBUT, seconds), fluorescein breakup time (FBUT, seconds), corneal epithelial damage (CED, 15 points maximum), conjunctival epithelial damage (CjED, six points maximum), the Schirmer’s 1 test (ST1, mm), and the prevalence of Sjögren’s syndrome (SS) were examined, and then compared between the two groups. Our findings revealed that between the groups (PPCS vs. non-PPCS), there was a statistically significant difference (p < 0.05) in CjED (3.1 ± 1.9 vs. 1.3 ± 1.6), ST1 (5.6 ± 7.4 vs. 14.8 ± 11.4), and the prevalence of SS (60.0% vs. 16.7%). Our findings suggest that DEDs and dry-eye patients with PPCS may indicate not only SS itself, but also the ophthalmological characteristics compatible with SS.

The Role of Endogenous Antimicrobial Peptides in Modulating Innate Immunity of the Ocular Surface in Dry Eye Diseases

The ocular surface has the challenging responsibility of maintaining a clear moist refractive surface while protecting the eye from exogenous pathogens and the environment. Homeostasis of the ocular surface, including its innate immune components, is altered in ocular surface disease states. In this review, we focus on antimicrobial peptides and the role they play in the immune response of the ocular surface during healthy states and dry eye diseases. Antimicrobial peptides are of special interest to the study of the ocular surface because of their various roles that include microbial threat neutralization, wound healing, and immune modulation. This review explores current literature on antimicrobial peptides in ocular surface diseases and discusses their therapeutic potential in ocular surface diseases and dry eye.

Conjunctival impression cytology and tear-film changes in cases with vitamin D deficiency

PURPOSE

To evaluate conjunctival surface cells and tear-film functions in cases with vitamin D deficiency.

METHODS

Thirty-six patients with serum vitamin D deficiency and 27 control subjects with normal serum vitamin D levels were included in this prospective study. The tear break-up time (TBUT), Schirmer II test, and conjunctival impression cytology tests were performed to all participants.

RESULTS

The mean serum vitamin D levels were 10.5 ± 5.0 µl in the study group and 33.9 ± 11.7 µl in the control group (p < 0.001). The median TBUT scores were 11 s and 17 s and the median Schirmer II values were 7.5 mm and 12 mm in the study and the control groups, respectively (p = 0.003, p = 0.049). According to the Nelson staging system, 69.4% of the patients in the study group had grade 2 or 3 impression cytology, whereas 18.5% of the participants in the control group had grade 2 or 3 impression cytology (p < 0.001).

CONCLUSION

Our study results showed that vitamin D deficiency may lead to dry eye causing conjunctival squamous metaplasia and loss of goblet cells on the ocular surface.

Shared gene signature between pterygium and meibomian gland dysfunction uncovered through gene-expression meta-analysis

BACKGROUND

Pterygium and meibomian gland dysfunction (MGD) are two clinically correlated ocular diseases. We propose to investigate the shared gene signature between pterygium and MGD.

METHODS

Microarray datasets were retrieved from the Gene Expression Omnibus (GEO) database. Initial processing of the data was performed using the R programming package. Gene-expression values were log2 transformed and normalized by quantile normalization. The differentially expressed genes (DEGs) in each individual dataset were analyzed by the limma package. The integration of different pterygium datasets and gene-expression meta-analysis was conducted by the NetworkAnalyst package. A Venn diagram was created to find the overlapped DEGs between MGD and pterygium datasets. Gene ontology enrichment and pathway analysis were performed using the ToppGene Suite.

RESULTS

We found 193 DEGs significantly up-regulated in pterygium, with the combined effect sizes ranging from 1.53 to 3.78. A gene signature consisting of 11 DEGs were found to be shared by pterygium and MGD (SPRR3, SERPINB13, NMU, KRT10, IL37, KRT6B, PI3, S100A2, MAL, AURKA, and RGCC), and bioinformatics analyses showed that these overlapped DEGs were significantly enriched in pathways related to keratinization, cell-cycle regulation, and formation of the cornified envelope.

CONCLUSION

We identified a shared gene signature between pterygium and MGD through gene-expression meta-analysis. The analysis of this signature underlined that keratinization-related pathways may play important roles in the development of these two clinically correlated pathologies.

Relationship Between Ocular Surface Epithelial Damage, Tear Abnormalities, and Blink in Patients With Dry Eye

PURPOSE

Considering that tears play the role of a lubricant, it is speculated that in the pathophysiology of dry eye, increased friction during blinking results in corneal and conjunctival damage, which may subsequently affect the blink. The purpose of this study was to investigate the relationship between ocular surface epithelial damage, tear abnormalities, and blinks in patients with dry eye.

METHODS

This study involved 45 eyes of 45 female patients with dry eye (mean age: 57.6 years). In all eyes, tear meniscus radius (mm), spread grade of the tear film lipid layer (SG: 1-5: 1 being the best), fluorescein breakup time (FBUT, seconds), corneal and bulbar conjunctival epithelial damage (CED: 15 points maximum and CONJUNCTIVAL EPITHELIAL DAMAGE (CjED): 6 points maximum, respectively), and Schirmer I test (ST1, mm) were evaluated. Blink rate (BR, blinks per minute), palpebral aperture height (mm), upper-eyelid opening-phase amplitude/upper-eyelid closing-phase amplitude (mm), upper-eyelid opening-phase duration/upper-eyelid closing-phase duration (ms), and upper-eyelid opening-phase maximum velocity/upper-eyelid closing-phase maximum velocity (mm/s) were measured using a custom-made high-speed blink analyzer. Finally, the factors that determine CED and CjED were investigated by multiple regression analysis, in which the parameters were chosen using the stepwise procedure.

RESULTS

CED and CjED were found to be described as 2.687 + (1.816 × SG) - (0.937 × FBUT) (R = 0.656, P < 0.0001) and 0.684 + (0.801 × SG) - (0.526 × FBUT) - (0.041 × ST1) + (0.010 × upper-eyelid closing-phase maximum velocity) (R = 0.714, P < 0.0001), respectively.

CONCLUSIONS

Although CED was significantly related to only tear abnormalities, CjED was significantly related to tear abnormalities and blinking.

Interferons and Dry Eye in Sjögren's Syndrome

Various cytokines, including interferon (IFN)-γ and IL-17, are augmented, and autoreactive T cells and B cells are activated in the immune pathogenesis of Sjögren's syndrome (SS). In particular, IFNs are involved in both the early stages of innate immunity by high level of type I IFN in glandular tissue and sera and the later stages of disease progression by type I and type II IFN producing T cells and B cells through B cell activating factor in SS. Genetically modified mouse models for some of these molecules have been reported and will be discussed in this review. New findings from human SS and animal models of SS have elucidated some of the mechanisms underlying SS-related dry eye. We will discuss IFN-γ and several other molecules that represent candidate targets for treating inflammation in SS-related dry eye.

Type I Interferon Signaling Is Required for Dacryoadenitis in the Nonobese Diabetic Mouse Model of Sjögren Syndrome

Nonobese diabetic (NOD) mice spontaneously develop lacrimal and salivary gland autoimmunity similar to human Sjögren syndrome. In both humans and NOD mice, the early immune response that drives T-cell infiltration into lacrimal and salivary glands is poorly understood. In NOD mice, lacrimal gland autoimmunity spontaneously occurs only in males with testosterone playing a role in promoting lacrimal gland inflammation, while female lacrimal glands are protected by regulatory T cells (Tregs). The mechanisms of this male-specific lacrimal gland autoimmunity are not known. Here, we studied the effects of Treg depletion in hormone-manipulated NOD mice and lacrimal gland gene expression to determine early signals required for lacrimal gland inflammation. While Treg-depletion was not sufficient to drive dacryoadenitis in castrated male NOD mice, chemokines (Cxcl9, Ccl19) and other potentially disease-relevant genes (Epsti1, Ubd) were upregulated in male lacrimal glands. Expression of Cxcl9 and Ccl19, in particular, remained significantly upregulated in the lacrimal glands of lymphocyte-deficient NOD-severe combined immunodeficiency (SCID) mice and their expression was modulated by type I interferon signaling. Notably, Ifnar1-deficient NOD mice did not develop dacryoadenitis. Together these data identify disease-relevant genes upregulated in the context of male-specific dacryoadenitis and demonstrate a requisite role for type I interferon signaling in lacrimal gland autoimmunity in NOD mice.

Conjunctival Inflammatory Gene Expression Profiling in Dry Eye Disease: Correlations With HLA-DRA and HLA-DRB1

Purpose: In several multicenter clinical trials, HLA-DR was found to be a potential biomarker of dry eye disease (DED)'s severity and prognosis. Given the fact that HLA-DR receptor is a heterodimer consisting in an alpha and a beta chain, we intended to investigate the correlation of inflammatory targets with the corresponding transcripts, HLA-DRA and HLA-DRB1, to characterize specific targets closely related to HLA-DR expressed in conjunctival cells from patients suffering from DED of various etiologies.

Methods: A prospective study was conducted in 88 patients with different forms of DED. Ocular symptom scores, ocular-staining grades, tear breakup time (TBUT) and Schirmer test were evaluated. Superficial conjunctival cells were collected by impression cytology and total RNAs were extracted for analyses using the new NanoString^® nCounter technology based on an inflammatory human code set containing 249 inflammatory genes.

Results: Two hundred transcripts were reliably detected in conjunctival specimens at various levels ranging from 1 to 222,546 RNA copies. Overall, from the 88 samples, 21 target genes showed a highly significant correlation (R > 0.8) with HLA-DRA and HLA-DRB1, HLA-DRA and B1 presenting the highest correlation (R = 0.9). These selected targets belonged to eight family groups, namely interferon and interferon-stimulated genes, tumor necrosis factor superfamily and related factors, Toll-like receptors and related factors, complement system factors, chemokines/cytokines, the RIPK enzyme family, and transduction signals such as the STAT and MAPK families.

Conclusions: We have identified a profile of 21 transcripts correlated with HLA-DR expression, suggesting closely regulated signaling pathways and possible direct or indirect interactions between them. The NanoString^® nCounter technology in conjunctival imprints could constitute a reliable tool in the future for wider screening of inflammatory biomarkers in DED, usable in very small samples. Broader combinations of biomarkers associated with HLA-DR could be analyzed to develop new diagnostic approaches, identify tighter pathophysiological gene signatures and personalize DED therapies more efficiently.

Regulation of kallikrein-related peptidases in the skin – from physiology to diseases to therapeutic options

Kallikrein-related peptidases (KLKs) constitute a family of 15 highly conserved serine proteases, which show a tissue-specific expression profile. This made them valuable tumour expression markers. It became evident that KLKs are involved in many physiological processes like semen liquefaction and skin desquamation. More recently, we have learnt that they are involved in many pathophysiological conditions and diseases making them promising target of therapeutic intervention. Therefore, regulation of KLKs raised the interest of numerous reports. Herein, we summarise the current knowledge on KLKs regulation with an emphasis on skin-relevant KLKs regulation processes. Regulation of KLKs takes place on the level of transcription, on protease activation and on protease inactivation. A variety of protease inhibitors has been described to interact with KLKs including the irreversible serine protease inhibitors (SERPINs) and the reversible serine protease inhibitors of Kazal-type (SPINKs). In an attempt to integrate current knowledge, we propose that KLK regulation has credentials as targets for therapeutic intervention.

TFOS DEWS II pathophysiology report

The TFOS DEWS II Pathophysiology Subcommittee reviewed the mechanisms involved in the initiation and perpetuation of dry eye disease. Its central mechanism is evaporative water loss leading to hyperosmolar tissue damage. Research in human disease and in animal models has shown that this, either directly or by inducing inflammation, causes a loss of both epithelial and goblet cells. The consequent decrease in surface wettability leads to early tear film breakup and amplifies hyperosmolarity via a Vicious Circle. Pain in dry eye is caused by tear hyperosmolarity, loss of lubrication, inflammatory mediators and neurosensory factors, while visual symptoms arise from tear and ocular surface irregularity. Increased friction targets damage to the lids and ocular surface, resulting in characteristic punctate epithelial keratitis, superior limbic keratoconjunctivitis, filamentary keratitis, lid parallel conjunctival folds, and lid wiper epitheliopathy. Hybrid dry eye disease, with features of both aqueous deficiency and increased evaporation, is common and efforts should be made to determine the relative contribution of each form to the total picture. To this end, practical methods are needed to measure tear evaporation in the clinic, and similarly, methods are needed to measure osmolarity at the tissue level across the ocular surface, to better determine the severity of dry eye. Areas for future research include the role of genetic mechanisms in non-Sjögren syndrome dry eye, the targeting of the terminal duct in meibomian gland disease and the influence of gaze dynamics and the closed eye state on tear stability and ocular surface inflammation.

The increase of aqueous tear volume by diquafosol sodium in dry-eye patients with Sjögren's syndrome: a pilot study

PurposeTo investigate the effect of 3% diquafosol sodium ophthalmic solution (DQS) on aqueous tear volume increase in dry-eye patients with Sjögren's syndrome (SS).MethodsIn this pilot study, 17 dry-eye patients with SS (1 male and 16 females; mean age: 66.4 years) were enrolled and underwent topical instillation of two ophthalmic solutions, artificial tears (AT) in one eye and DQS in the fellow eye, in a masked manner. The central lower tear meniscus radius (TMR) curvature was measured before and at 15 min after instillation by video-meniscometry. Simultaneously, all patients self-evaluated their symptoms of wetness and stinging using a visual analog scale (VAS, in millimeters).ResultsTopical instillation of DQS significantly increased the TMR at 15 min (mean: 0.21±0.08 (SD) mm) compared with at baseline (mean: 0.16±0.07 mm) (P<0.001, paired t-test), whereas AT had no effect at baseline (mean: 0.18±0.09 mm) or at 15 min (mean: 0.18±0.09 mm). The visual VAS score of wetness at 15-min post-instillation increased in both groups compared with at baseline. In the DQS-treated eyes, the post-instillation change in TMR from baseline was not correlated with the baseline value of the Schirmer test, corneal staining score, or conjunctival staining score.ConclusionsTopical instillation of DQS increased aqueous tear volume on the ocular surface of dry-eye patients with SS, with its action being independent of lacrimal gland function.

Storage Temperature Alters the Expression of Differentiation-Related Genes in Cultured Oral Keratinocytes

Purpose

Storage of cultured human oral keratinocytes (HOK) allows for transportation of cultured transplants to eye clinics worldwide. In a previous study, one-week storage of cultured HOK was found to be superior with regard to viability and morphology at 12°C compared to 4°C and 37°C. To understand more of how storage temperature affects cell phenotype, gene expression of HOK before and after storage at 4°C, 12°C, and 37°C was assessed.

Materials and Methods

Cultured HOK were stored in HEPES- and sodium bicarbonate-buffered Minimum Essential Medium at 4°C, 12°C, and 37°C for one week. Total RNA was isolated and the gene expression profile was determined using DNA microarrays and analyzed with Partek Genomics Suite software and Ingenuity Pathway Analysis. Differentially expressed genes (fold change > 1.5 and P < 0.05) were identified by one-way ANOVA. Key genes were validated using qPCR.

Results

Gene expression of cultures stored at 4°C and 12°C clustered close to the unstored control cultures. Cultures stored at 37°C displayed substantial change in gene expression compared to the other groups. In comparison with 12°C, 2,981 genes were differentially expressed at 37°C. In contrast, only 67 genes were differentially expressed between the unstored control and the cells stored at 12°C. The 12°C and 37°C culture groups differed most significantly with regard to the expression of differentiation markers. The Hedgehog signaling pathway was significantly downregulated at 37°C compared to 12°C.

Conclusion

HOK cultures stored at 37°C showed considerably larger changes in gene expression compared to unstored cells than cultured HOK stored at 4°C and 12°C. The changes observed at 37°C consisted of differentiation of the cells towards a squamous epithelium-specific phenotype. Storing cultured ocular surface transplants at 37°C is therefore not recommended. This is particularly interesting as 37°C is the standard incubation temperature used for cell culture.

Aqueous Tear Deficiency Increases Conjunctival Interferon-γ (IFN-γ) Expression and Goblet Cell Loss

PURPOSE

To investigate the hypothesis that increased interferon-γ (IFN-γ) expression is associated with conjunctival goblet cell loss in subjects with tear dysfunction.

METHODS

Goblet cell density (GCD) was measured in impression cytology from the temporal bulbar conjunctiva, and gene expression was measured in cytology samples from the nasal bulbar conjunctiva obtained from 68 subjects, including normal control, meibomian gland disease (MGD), non-Sjögren syndrome (non-SSATD)-, and Sjögren syndrome (SSATD)-associated aqueous tear deficiency. Gene expression was evaluated by real-time PCR. Tear meniscus height (TMH) was measured by optical coherence tomography. Fluorescein and lissamine green dye staining evaluated corneal and conjunctival disease, respectively. Between-group mean differences and correlation coefficients were calculated.

RESULTS

Compared to control, IFN-γ expression was significantly higher in both ATD groups, and its receptor was higher in SSATD. Expression of IL-13 and its receptor was similar in all groups. Goblet cell density was lower in the SSATD group; expression of MUC5AC mucin was lower and cornified envelope precursor small proline-rich region (SPRR)-2G higher in both ATD groups. Interferon-γ transcript number was inversely correlated with GCD (r = -0.37, P < 0.04) and TMH (r = -0.37, P = 0.02), and directly correlated with lissamine green staining (r = 0.51, P < 0.001) and SPRR-2G expression (r = 0.32, P < 0.05).

CONCLUSIONS

Interferon-γ expression in the conjunctiva was higher in aqueous deficiency and correlated with goblet cell loss and severity of conjunctival disease. These results support findings of animal and culture studies showing that IFN-γ reduces conjunctival goblet cell number and mucin production.

Three percent diquafosol ophthalmic solution as an additional therapy to existing artificial tears with steroids for dry-eye patients with Sjögren's syndrome

PURPOSE

To investigate the long-term results of 3% diquafosol ophthalmic solution as an alternative therapy to existing ophthalmic solutions, including topical immunosuppression, for the treatment of dry eye in patients with Sjögren's syndrome.

METHODS

This study involved 14 female dry-eye patients (mean age: 62.4 years) with Sjögren's syndrome who insufficiently responded to their current therapy. In all patients, 3% diquafosol ophthalmic solution was administered six times daily for 12 months in substitution for artificial tears and sodium hyaluronate ophthalmic solution. Their use of corticosteroid eye drops remained unchanged from that prior to the treatment with diquafosol sodium. The subjective symptoms assessed, and ocular signs including tear meniscus radius and the tear film breakup time, and ocular-surface epithelial damage score were examined at 1, 2, 3, 4, 5, 6, 9, and 12 months after initiating treatment.

RESULTS

Among the subjective symptoms, significant improvement was obtained in dryness at 2 months post treatment, in eye fatigue at 1, 2, 3, 4, and 12 months post treatment, and in pain at 1, 2, 6, and 12 months post treatment. Difficulty in opening the eye, foreign body sensation, and redness were also significantly ameliorated at various time-points. The tear meniscus radius and the tear film breakup time were significantly improved throughout the observation period, and the corneal epithelial staining scores were significantly decreased at 3 months post treatment.

CONCLUSIONS

In dry-eye patients with Sjögren's syndrome, treatment with 3% diquafosol ophthalmic solution improved both symptoms and signs, and that effectiveness was maintained for 12 months.

Effects of topical loteprednol etabonate on tear cytokines and clinical outcomes in moderate and severe meibomian gland dysfunction: randomized clinical trial

PURPOSE

To assess tear cytokine levels and clinical outcomes in moderate and severe meibomian gland dysfunction (MGD) after 2 months of treatment with topical loteprednol etabonate and eyelid scrubs with warm compresses vs eyelid scrubs with warm compresses alone.

DESIGN

Randomized controlled trial.

METHODS

Patients with moderate and severe MGD were randomized into 2 groups: topical loteprednol etabonate and eyelid scrubs with warm compresses (Group I, 34 eyes) or eyelid scrubs with warm compresses (Group II, 36 eyes). We evaluated cytokine levels, tear film break-up time (TBUT), corneal and conjunctival fluorescein staining, biomicroscopic examination of lid margins and meibomian glands, and the Ocular Surface Disease Index before initiating treatment and 1 month and 2 months after treatment.

RESULTS

There were significant decreases in the levels of interleukin (IL)-6, IL-8, and IL-1β in Group I, and IL-6 and IL-8 in Group II. Moreover, the observed decreases of these cytokines in Group I were attributed to a remarkable decrease between treatment and 1 month after treatment. In Group I, there were improvements in all of the clinical outcomes, with prominent improvement in TBUT, corneal and conjunctival fluorescein staining, and meibum quality after 1 month of treatment, compared with Group II. An improvement in meibomian gland expressibility and MGD stage reduction were more remarkable in Group I.

CONCLUSIONS

Topical loteprednol etabonate and eyelid scrubs with warm compresses were tolerated and efficacious for the treatment of moderate and severe MGD. We suggest that such beneficial effects could manifest after 1 month.

[Testosterone reduces the expression of keratinization-promoting genes in murine Meibomian glands]

BACKGROUND

Extensive keratinization appears to play a major role in the dysfunction of the Meibomian gland. This article presents the potential impact of androgens on limiting keratinization in this tissue, thus, contributing to normal Meibomian gland function and a healthy ocular surface.

MATERIALS AND METHODS

Orchidectomized mice were systemically treated with either testosterone or placebo for 2 weeks. The mRNA was then extracted from the Meibomian glands and differential gene expression was investigated by microarray hybridization and evaluation with GeneSifter software as well as gene ontology information from the Gene Ontology (GO) Consortium.

RESULTS

By z-score calculations, keratinization was the most significantly gene ontology term influenced by testosterone based on down-regulated genes in the mouse Meibomian gland. In particular, under the influence of testosterone the genes coding for small proline-rich protein (Sprr) 2a, Sprr 2b, Sprr 3, keratins 6a and 17 and periplakin were significantly down-regulated, while Sprr 1a and Sprr 2f were significantly up-regulated.

CONCLUSIONS

Testosterone down-regulates the expression of genes promoting keratinization in the Meibomian gland. This may help to prevent Meibomian gland dysfunction by limiting excessive keratinization of this tissue and the adjacent lid margins. The findings elucidate, at least in part, the beneficial impact of androgens on Meibomian gland function and thus on th e health of the ocular surface.

Adaptation of impression cytology to enable conjunctival surface cell transcriptome analysis

PURPOSE

This study investigates the extent of the human transcriptome that can be quantified from conjunctival impression cytology extracts. The aim is to determine if sufficient RNA can be isolated from a patient's conjunctival surface to identify differences in gene expression between dry eye and normal patients of (a) an array of 96 inflammatory biomarkers and associated receptors, and (b) if this comparison can be expanded to the entire transcriptome.

MATERIALS AND METHODS

CIC was used to collect conjunctival surface cells from 53 qualifying normal and dry eye patients. Based on prior optimization of all assay steps, RNA was isolated from the samples using a Qiagen RNeasy Plus Mini Kit and qRT-PCR was used to determine gene expression of 96 genes using TaqMan Low Density Array cards. Samples from six normal and six dry eye patients were then assayed on an Illumina Human HT-12 BeadChip.

RESULTS

Optimization steps yielded an RNA processing procedure that improved yield from an initial 12 genes through 96, then to the entire human transcriptome. For the HT-12 BeadChip, more than 30 genes differed by a factor of >1.5 between the dry eye and normal groups and seven genes were down-regulated by a factor of >2.0 in the dry eye group: HLA-DRB5, PSCA, FOS, lysozyme, TSC22D1, CAPN13 and CXCL6.

CONCLUSIONS

Conjunctival impression cytology can be used to collect sufficient RNA from conjunctival surface cells that, when processed optimally, allows successful transcriptome-wide expression analysis. While the current transcriptome analysis used a limited patient group, larger studies of patients with various types and severities of dry eye should reveal significant gene expression trends that can then be targeted to improve dry eye treatment options.

The influence of 13-cis retinoic acid on human meibomian gland epithelial cells

PURPOSE

Meibomian gland dysfunction (MGD) is a primary cause of dry eye disease. One of the risk factors for MGD is exposure to 13-cis retinoic acid (13-cis RA), a metabolite of vitamin A. However, the mechanism is not well understood. We hypothesize that 13-cis RA inhibits cell proliferation, promotes cell death, alters gene and protein expressions, and attenuates cell survival pathways in human meibomian gland epithelial cells.

METHODS

To test our hypotheses, immortalized human meibomian gland epithelial cells were cultured with or without 13-cis RA for varying doses and time. Cell proliferation, cell death, gene expression, and proteins involved in proliferation/survival and inflammation were evaluated.

RESULTS

We found that 13-cis RA inhibited cell proliferation, induced cell death, and significantly altered the expression of 6726 genes, including those involved in cell proliferation, cell death, differentiation, keratinization, and inflammation, in human meibomian gland epithelial cells. Further, 13-cis RA also reduced the phosphorylation of Akt and increased the generation of interleukin-1β and matrix metallopeptidase 9.

CONCLUSIONS

Exposure to 13-cis RA inhibits cell proliferation, increases cell death, alters gene expression, changes signaling pathways, and promotes inflammatory mediator and protease expression in meibomian gland epithelial cells. These effects may be responsible, at least in part, for the 13-cis RA-related induction of MGD.

Surfactant protein D contributes to ocular defense against Pseudomonas aeruginosa in a murine model of dry eye disease

Dry eye disease can cause ocular surface inflammation that disrupts the corneal epithelial barrier. While dry eye patients are known to have an increased risk of corneal infection, it is not known whether there is a direct causal relationship between these two conditions. Here, we tested the hypothesis that experimentally-induced dry eye (EDE) increases susceptibility to corneal infection using a mouse model. In doing so, we also examined the role of surfactant protein D (SP-D), which we have previously shown is involved in corneal defense against infection. Scopolamine injections and fan-driven air were used to cause EDE in C57BL/6 or Black Swiss mice (wild-type and SP-D gene-knockout). Controls received PBS injections and were housed normally. After 5 or 10 days, otherwise uninjured corneas were inoculated with 10(9) cfu of Pseudomonas aeruginosa strain PAO1. Anesthesia was maintained for 3 h post-inoculation. Viable bacteria were quantified in ocular surface washes and corneal homogenates 6 h post-inoculation. SP-D was measured by Western immunoblot, and corneal pathology assessed from 6 h to 4 days. EDE mice showed reduced tear volumes after 5 and 10 days (each by ∼75%, p<0.001) and showed fluorescein staining (i.e. epithelial disruption). Surprisingly, there was no significant difference in corneal pathology between EDE mice and controls (∼10-14% incidence). Before bacterial inoculation, EDE mice showed elevated SP-D in ocular washes. After inoculation, fewer bacteria were recovered from ocular washes of EDE mice (<2% of controls, p = 0.0004). Furthermore, SP-D knockout mice showed a significant increase in P. aeruginosa corneal colonization under EDE conditions. Taken together, these data suggest that SP-D contributes to corneal defense against P. aeruginosa colonization and infection in EDE despite the loss of barrier function to fluorescein.

Effect of growth factors on the proliferation and gene expression of human meibomian gland epithelial cells

PURPOSE

We hypothesize that growth factors, including epidermal growth factor (EGF) and bovine pituitary extract (BPE), induce proliferation, but not differentiation (e.g., lipid accumulation), of human meibomian gland epithelial cells. We also hypothesize that these actions involve a significant upregulation of genes linked to cell cycle processes, and a significant downregulation of genes associated with differentiation. Our objective was to test these hypotheses.

METHODS

Immortalized human meibomian gland and conjunctival epithelial cells were cultured for varying time periods in the presence or absence of EGF, BPE, EGF + BPE, or serum, followed by cell counting, neutral lipid staining, or RNA isolation for molecular biological procedures.

RESULTS

Our studies show that growth factors stimulate a significant, time-dependent proliferation of human meibomian gland epithelial cells. These effects are associated with a significant upregulation of genes linked to cell cycle, DNA replication, ribosomes, and translation, and a significant decrease in those related to cell differentiation, tissue development, lipid metabolic processes, and peroxisome proliferator-activated receptor signaling. Serum-induced differentiation, but not growth factor-related proliferation, elicits a pronounced lipid accumulation in human meibomian gland epithelial cells. This lipogenic response is unique, and is not duplicated by human conjunctival epithelial cells.

CONCLUSIONS

Our results demonstrate that EGF and BPE stimulate human meibomian gland epithelial cells to proliferate. Further, our findings show that action is associated with an upregulation of cell cycle and translation ontologies, and a downregulation of genetic pathways linked to differentiation and lipid biosynthesis.

Dry eye disease and microbial keratitis: is there a connection?

Dry eye is a common ocular surface disease of multifactorial etiology characterized by elevated tear osmolality and inflammation leading to a disrupted ocular surface. The latter is a risk factor for ocular surface infection, yet overt infection is not commonly seen clinically in the typical dry eye patient. This suggests that important innate mechanisms operate to protect the dry eye from invading pathogens. This article reviews the current literature on epidemiology of ocular surface infection in dry eye patients and laboratory-based studies on innate immune mechanisms operating at the ocular surface and their alterations in human dry eye and animal models. The review highlights current understanding of innate immunity in dry eye and identifies gaps in our knowledge to help direct future studies to further unravel the complexities of dry eye disease and its sequelae.

Interleukin-1 receptor mediates the interplay between CD4+ T cells and ocular resident cells to promote keratinizing squamous metaplasia in Sjögren's syndrome

Keratinizing squamous metaplasia (SQM) of the ocular mucosal epithelium is a blinding corneal disease characterized by the loss of conjunctival goblet cells (GCs), pathological ocular surface keratinization and tissue recruitment of immune cells. Using the autoimmune regulator (Aire)-deficient mouse as a model for Sjögren's syndrome (SS)-associated SQM, we identified CD4(+) T lymphocytes as the main immune effectors driving SQM and uncovered a pathogenic role for interleukin-1 (IL-1). IL-1, a pleiotropic cytokine family enriched in ocular epithelia, governs tissue homeostasis and mucosal immunity. Here, we used adoptive transfer of autoreactive CD4(+) T cells to dissect the mechanism whereby IL-1 promotes SQM. CD4(+) T cells adoptively transferred from both Aire knockout (KO) and Aire/IL-1 receptor type 1 (IL-1R1) double KO donors conferred SQM to severe-combined immunodeficiency (scid) recipients with functional IL-1R1, but not scid recipients lacking IL-1R1. In the lacrimal gland, IL-1R1 was primarily immunolocalized to ductal epithelium surrounded by CD4(+) T cells. In the eye, IL-1R1 was expressed on local mucosal epithelial and stromal cells, but not on resident antigen-presenting cells or infiltrating immune cells. In both tissues, autoreactive CD4(+) T-cell infiltration was only observed in the presence of IL-1R1-postive resident cells. Moreover, persistent activation of IL-1R1 signaling led to chronic immune-mediated inflammation by retaining CD4(+) T cells in the local microenvironment. Following IL-1R1-dependent infiltration of CD4(+) T cells, we observed SQM hallmarks in local tissues-corneal keratinization, conjunctival GC mucin acidification and epithelial cell hyperplasia throughout the ocular surface mucosa. Proinflammatory IL-1 expression in ocular epithelial cells significantly correlated with reduced tear secretion, while CD4(+) T-cell infiltration of the lacrimal gland predicted the development of ocular SQM. Collectively, data in this study indicated a central role for IL-1 in orchestrating a functional interplay between immune cells and resident cells of SS-targeted tissues in the pathogenesis of SQM.

Age-related changes in tear menisci imaged by optical coherence tomography

PURPOSE

To determine age-related changes of tear menisci in healthy subjects and to compare tear variables between age-matched normals and dry eye subjects.

METHODS

Anterior segment optical coherence tomography was used to measure upper and lower tear menisci in healthy subjects (n = 197, 8-83 years) and in age-matched dry eye patients (n = 38, 19-72 years). Measured tear variables included the height and area of the tear meniscus. Tear meniscus volumes were calculated based on the cross-sectional areas of the tear menisci and the eyelid lengths. The age-related decrease rates of the tear menisci were also calculated.

RESULTS

There were significant negative correlations between age and all tear meniscus dimensions (r ranged from -0.649 to -0.753; p < 0.05) in the healthy group. The rate of decrease for the total tear meniscus volume in healthy subjects was 1.0% per year. Compared with age-matched healthy subjects, the height, cross-sectional area, and volume of the upper and lower tear menisci in dry eye subjects were significantly smaller (p < 0.05).

CONCLUSIONS

Tear menisci decreased with age in the healthy group. The variables in age-matched dry eye subjects were significantly lower than those in the healthy group.

Expression of CCR5 and its ligands CCL3, -4, and -5 in the tear film and ocular surface of patients with dry eye disease

PURPOSE

To evaluate the expression of CCR5 and its ligands CCL3, CCL4, and CCL5 in the tear film and ocular surface and their correlation with disease severity in patients with dry eye disease.

MATERIALS AND METHODS

The concentrations of CCL3, CCL4, and CCL5 were measured using enzyme-linked immunosorbent assay in tear samples obtained from forty-three patients with dry eye (17 SS and 26 non-SS patients) and 20 control subjects. The correlation between chemokine levels and tear film and ocular surface parameters was analyzed. Expression of the chemokines and their receptor in the conjunctiva was evaluated using immunohistochemistry. Flow cytometry was performed to detect CCR4+CD4+, CCR5+CD4+, and CCR6+CD4+ cells in the conjunctiva.

RESULTS

The concentrations of CCL3, CCL4, and CCL5 were 25.3 ± 24.2, 4.65 ± 3.21, and 93.12 ± 26.31 pg/mL in control subjects, 92.33 ± 13.23, 263.13 ± 116.13, and 253.64 ± 46.29 pg/mL in patients with non-SS, and 215.56 ± 36.1, 697.85 ± 185.65, and 456.12 ± 92.82 pg/mL in patients with SS. The concentrations showed a significant increase in tears of SS patients compared with those of non-SS patients and control subjects (p < 0.05). CCL5 levels showed significant correlation with tear film break-up time, basal tear secretion, tear clearance rate, keratoepitheliopathy score, and goblet cell density (p < 0.01). Staining for the chemokines and their receptor increased in dry eye patients, especially in those with SS patients. Flow cytometry demonstrated increased numbers of CCR5+CD4+, and CCR6+CD4+ cells in dry eye patients in contrast to CCR4+CD4+ cells.

CONCLUSIONS

Expression of CCR5 and its ligands CCL3, CCL4, and CCL5 increase in the tear film and ocular surface of patients with dry eye syndrome, especially in those with SS. CCL5 levels correlate significantly with various tear film and ocular surface parameters.

Role of host-defence peptides in eye diseases

The eye and its associated tissues including the lacrimal system and lids have evolved several defence mechanisms to prevent microbial invasion. Included among this armory are several host-defence peptides. These multifunctional molecules are being studied not only for their endogenous antimicrobial properties but also for their potential therapeutic effects. Here the current knowledge of host-defence peptide expression in the eye will be summarised. The role of these peptides in eye disease will be discussed with the primary focus being on infectious keratitis, inflammatory conditions including dry eye and wound healing. Finally the potential of using host-defence peptides and their mimetics/derivatives for the treatment and prevention of eye diseases is addressed.

Changes in gene expression in human meibomian gland dysfunction

PURPOSE

Meibomian gland dysfunction (MGD) may be the leading cause of dry eye syndrome throughout the world. However, the precise mechanism(s) underlying the pathogenesis of this disease is unclear. This study was conducted to identify meibomian gland genes that may promote the development and/or progression of human MGD.

METHODS

Lid tissues were obtained from male and female MGD patients and age-matched controls after eyelid surgeries (e.g., to correct entropion or ectropion). Meibomian glands were isolated and processed for RNA extraction and the analysis of gene expression.

RESULTS

The results show that MGD is associated with significant alterations in the expression of almost 400 genes in the human meibomian gland. The levels of 197 transcripts, including those encoding various small proline-rich proteins and S100 calcium-binding proteins, are significantly increased, whereas the expression of 194 genes, such as claudin 3 and cell adhesion molecule 1, is significantly decreased. These changes, which cannot be accounted for by sex differences, are accompanied by alterations in many gene ontologies (e.g., keratinization, cell cycle, and DNA repair). The findings also show that the human meibomian gland contains several highly expressed genes that are distinct from those in an adjacent tissue (i.e., conjunctival epithelium).

CONCLUSIONS

The results demonstrate that MGD is accompanied by multiple changes in gene expression in the meibomian gland. The nature of these alterations, including the upregulation of genes encoding small proline-rich proteins and S100 calcium-binding proteins, suggest that keratinization plays an important role in the pathogenesis of MGD.

Proteome analysis of biological fluids from autoimmune-rheumatological disorders

Autoimmune-rheumatological diseases are worldwide distributed disorders and represent a complex array of illnesses characterized by autoreactivity (reactivity against self-antigens) of T-B lymphocytes and by the synthesis of autoantibodies crucial for diagnosis (biomarkers). Yet, the effects of the autoimmune chronic inflammation on the infiltrated tissues and organs generally lead to profound tissue and organ damage with loss of function (i.e., lung, kidney, joints, exocrine glands). Although progresses have been made on the knowledge of these disorders, much still remains to be investigated on their pathogenesis and identification of new biomarkers useful in clinical practice. The rationale of using proteomics in autoimmune-rheumatological diseases has been the unmet need to collect, from biological fluids that are easily obtainable, a summary of the final biochemical events that represent the effects of the interplay between immune cells, mesenchymal cells and endothelial cells. Proteomic analysis of these fluids shows encouraging results and in this review, we addressed four major autoimmune-rheumatological diseases investigated through proteomic techniques and provide evidence-based data on the highlights obtained in systemic sclerosis, primary and secondary Sjogren's syndrome, systemic lupus erythematosus and rheumatoid arthritis.

Kallikrein-related peptidases: bridges between immune functions and extracellular matrix degradation

Kallikrein-related peptidases (KLKs) constitute a family of 15 highly conserved serine proteases encoded by the largest uninterrupted cluster of protease-encoding genes within the human genome. Recent studies, mostly relying on in vitro proteolysis of recombinant proteins, have suggested that KLK activities are regulated by proteolytic activation cascades that can operate in a tissue-specific manner, such as the semen liquefaction and skin desquamation cascades. The validity of KLK activation cascades in vivo largely remains to be demonstrated. Here, we focus on recent investigations showing that KLKs represent interesting players in the broader field of immunology based on their ability to bridge their inherent ability to degrade the extracellular matrix with major functions of the immune system. More specifically, KLKs assist in the infiltration of immune cells through the skin and the blood brain barrier, whereas they catalyze the generation of antimicrobial peptides by proteolytic activation and further processing of protein precursors. In an attempt to integrate current knowledge, we propose KLK-mediated pathways that are putatively involved in inflammation associated with skin wounding and central nervous system disorders, including multiple sclerosis. Finally, we present evidence of KLK participation in autoimmune diseases and allergies.

Proteomic approaches to Sjögren's syndrome: a clue to interpret the pathophysiology and organ involvement of the disease

Sjögren's syndrome (SS) is a chronic, inflammatory, autoimmune disease characterized by lymphocytic infiltration of the exocrine glands leading to qualitatively altered and diminished or absent salivary and lachrymal secretion, and by marked B-cell hyperreactivity. Many efforts have been made to define a panel of salivary and lachrymal markers helpful to design diagnostic tests able to replace blood tests and tissue biopsies for the diagnosis of primary and secondary SS. Several proteomic-based studies have indicated that a number of proteins and peptides can be considered SS biomarkers, being 2-3-fold up- or down-regulated compared to normal subject or having an exclusive presence in the saliva or tears of SS patients. Unfortunately, several factors make it difficult to define a comprehensive salivary and lachrymal panel of markers of SS, as the lack of a comprehensive proteomic analysis of human tears and saliva of healthy subjects, the lack of uniform protocols to collect and treat these samples, and the high grade of posttranslational modification of the proteins in these fluids.

Molecular mechanism of proinflammatory cytokine-mediated squamous metaplasia in human corneal epithelial cells

PURPOSE

The cornified envelope protein small proline-rich protein 1B (SPRR1B) is a biomarker for squamous metaplasia. Proinflammatory cytokines IL-1beta and IFN-gamma are potent inducers of ocular surface keratinization and SPRR1B expression. Here the molecular mechanisms controlling SPRR1B gene expression in response to IL-1beta and IFN-gamma are elucidated.

METHODS

A 3-kb fragment of the SPRR1B gene 5'-flanking region was amplified from human chromosome 1, sequentially deleted, and cloned into a luciferase vector. Constructs were transiently transfected into human corneal epithelial cells, and activity was assessed in response to IL-1beta, IFN-gamma, or basal medium. Functional cis-elements responding to IL-1beta and IFN-gamma were characterized by site-directed mutagenesis and gel mobility shift assay. Effects of mitogen-activated protein kinases p38, ERK, and JNK were assessed using inhibitors and dominant-negative mutants. Results were validated by real-time RT-PCR.

RESULTS

The first 620 bp of the SPRR1B 5'-flanking region regulated constitutive expression and increased promoter activity in response to IL-1beta and IFN-gamma. Corresponding cis-elements for IL-1beta and IFN-gamma were bound by cAMP response element binding protein (CREB) and zinc-finger E-box binding homeobox 1 (ZEB1), respectively. Inhibition of p38 abolished the stimulatory effects of IL-1beta and IFN-gamma on SPRR1B, whereas inhibition of JNK and ERK had no effect. Dominant-negative mutants targeting p38alpha and p38beta2 blocked cytokine-induced SPRR1B promoter activity and mRNA expression.

CONCLUSIONS

SPRR1B is upregulated by the proinflammatory cytokines IL-1beta and IFN-gamma via p38 MAPK-mediated signaling pathways that lead to the activation of transcription factors CREB and ZEB1, respectively. These results identify key intracellular signaling intermediates involved in the pathogenesis of immune-mediated ocular surface squamous metaplasia.

The role of antimicrobial peptides at the ocular surface

Antimicrobial peptides (AMPs) such as defensins and cathelicidins are small peptides with broad-spectrum activity against bacteria, fungi and viruses. In addition, several AMPs modulate mammalian cell behaviours including migration, proliferation and cytokine production. This review describes findings from recent studies showing the presence of various AMPs at the human ocular surface and discusses their mechanism of antimicrobial action and potential non-microbicidal roles. Corneal and conjunctival epithelial cells produce beta-defensins and the cathelicidin LL-37, whereas neutrophils, infiltrating in response to a specific stimulus, supply additional LL-37 as well as alpha-defensins. In vitro studies suggest that LL-37 and human beta-defensin-3 are the most likely to have significant independent antimicrobial activity, while other AMPs may act synergistically to help protect the ocular surface from invading pathogens. Current evidence also supports a role for some AMPs in modulating wound healing responses. Although yet to be brought to fruition, AMPs hold significant potential as therapeutic agents for the prophylaxis and treatment of infection, promotion of wound healing and immune modulation.

Small proline-rich protein 1B (SPRR1B) is a biomarker for squamous metaplasia in dry eye disease

PURPOSE

Squamous metaplasia occurs in ocular surface diseases like Sjögren's syndrome (SS). It is a phenotypic change whereby epithelial cells initiate synthesis of squamous cell-specific proteins such as small proline-rich protein 1B (SPRR1B) that result in pathologic keratin formation on the ocular surface. The authors hypothesized that inflammation is a key inducer of pathologic keratinization and that SPRR1B represents an analytical biomarker for the study of the molecular mechanisms.

METHODS

Real-time quantitative RT-PCR and immunohistochemistry were used to examine SPRR1B mRNA and protein in two different mouse models of dry eye and patients with SS. Adoptive transfer of mature lymphocytes from mice lacking the autoimmune regulator (aire) gene was performed to examine the role of inflammation as an inducer of squamous metaplasia. SPRR1B expression in response to several cytokines was examined in vitro, whereas the expression of cytokines IL1beta and IFNgamma was quantified in ocular tissues of aire-deficient mice and patients with SS.

RESULTS

SPRR1B was increased across the ocular surface of mice with both desiccating stress and autoimmune-mediated, aqueous-deficient dry eye and in patients with SS. Adoptive transfer of CD4(+) T cells from aire-deficient mice to immunodeficient recipients caused advanced ocular surface keratinization. IL1alpha, IL1beta, IL6, IFNgamma, and TNFalpha induced SPRR1B expression in vitro and the local expression of IL1beta and IFNgamma was elevated in ocular tissues of patients with SS and aire-deficient mice.

CONCLUSIONS

SPRR1B is a valid biomarker for the study of the molecular mechanisms of squamous metaplasia. There is a definitive link between inflammation and squamous metaplasia in autoimmune-mediated dry eye disease, with IL1beta and IFNgamma likely acting as key participants.

Small proline-rich proteins (SPRR) function as SH3 domain ligands, increase resistance to injury and are associated with epithelial-mesenchymal transition (EMT) in cholangiocytes

BACKGROUND/AIMS

Deficient biliary epithelial cell (BEC) expression of small proline-rich protein (SPRR) 2A in IL-6(-/-) mice is associated with defective biliary barrier function after bile duct ligation. And numerous gene array expression studies show SPRR2A to commonly be among the most highly up-regulated genes in many non-squamous, stressed and remodeling barrier epithelia. Since the function of SPRR in these circumstances is unknown, we tested the exploratory hypothesis that BEC SPRR2A expression contributes to BEC barrier function and wound repair.

METHODS

The effect of SPRR2A expression was studied in primary mouse BEC cultures; in a BEC cell line after forced overexpression of SPRR2A; and in human livers removed at the time of liver transplantation.

RESULTS

Forced SPRR2A overexpression showed that it functions as a SH3 domain ligand that increases resistance to oxidative injury and promotes wound restitution by enhancing migration and acquisition of mesenchymal characteristics. Low confluency non-neoplastic mouse BEC cultures show a phenotype similar to the stable transfectants, as did spindle-shaped BEC participating in atypical ductular reactions in primary biliary cirrhosis.

CONCLUSIONS

These observations suggest that SPRR2A-related BEC barrier modifications represent a novel, but widely utilized and evolutionarily conserved, response to stress that is worthy of further study.

Role of beta-defensins in oral epithelial health and disease

The oral epithelium functions as a mechanical and protective barrier to resist bacterial infection. beta-Defensins are a group of antimicrobial peptides mainly produced by epithelial cells of many organs including skin, lung, kidney, pancreas, uterus, eye, and nasal and oral mucosa. This review focuses on beta-defensins (BDs) in oral epithelia and discusses their importance in oral epithelial health and disease. BDs exhibit antimicrobial activity against oral microbes including periodontitis-related bacteria, Candida, and papilloma virus. Alterative expression of BDs was observed in oral epithelial diseases, including oral inflammatory lesions with and without microbial infection and oral cancer. BDs may be useful in the treatment of oral infectious diseases, ulcerative lesions, and cancer. BDs play an important role in protection against oral microbes and may be used in clinical applications.

Proteomic study of salivary peptides and proteins in patients with Sjögren's syndrome before and after pilocarpine treatment

OBJECTIVE

To investigate the effect of pilocarpine on the salivary peptide and protein profile in patients with primary Sjögren's syndrome (SS) and to study the differences between patients with primary SS, patients with SS associated with other rheumatic diseases, and healthy control subjects.

METHODS

Saliva specimens were obtained from 9 primary SS patients, 9 secondary SS patients, and 10 healthy controls. Samples were analyzed for levels of 62 different salivary proteins using high-performance liquid chromatography coupled with mass spectrometry using a spectrometer equipped with an electrospray ionization source. In 6 of the primary SS patients, saliva was collected at 30 minutes, 60 minutes, and 24 hours after taking 5 mg of pilocarpine.

RESULTS

Before pilocarpine, approximately 60% of salivary proteins in samples from primary SS patients were not identifiable or showed lower levels than those in healthy controls. After 30-60 minutes following pilocarpine treatment, approximately one-third of the less represented proteins was found in a similar percentage of primary SS patients and controls. Almost all of the proteins that were detectable at lower levels in primary SS patients compared with controls reached levels similar to those in controls at 30-60 minutes after pilocarpine. The parotid gland proteins had the best response to pilocarpine. Primary SS patients were characterized by higher alpha-defensin 1 levels and by the presence of beta-defensin 2. Secondary SS patients showed an intermediate protein profile between that of the primary SS patients and the controls.

CONCLUSION

Pilocarpine partially restored the levels and numbers of identifiable proteins in saliva from patients with primary SS. Higher levels of alpha-defensin 1 and the presence of beta-defensin 2 in the saliva of patients with primary SS could be markers of oral inflammation in this patient group.

Gene expression profiling in human autoimmunity

Human autoimmune diseases are well suited for the application of gene expression profiling. Sampling of blood cells and target tissues has already revealed many important pathways contributing to this spectrum of disorders, and many commonalities are emerging. For instance, clinically distinct diseases such as systemic lupus erythematosus, Sjögren's syndrome, dermatomyositis, and psoriasis all show evidence for dysregulation of the type I interferon pathway. These data suggest that autoimmune diseases will eventually be categorized at the level of gene expression. This work has led to advances in our understanding of disease pathogenesis and in the future promises to facilitate assessments of disease activity and improve targeting of therapies. Here, we review the literature on gene profiling in human autoimmune diseases and provide perspective on the current state of the art.

Research in Dry Eye: Report of the Research Subcommittee of the International Dry Eye WorkShop (2007)

Members of the DEWS Research Subcommittee reviewed research into the basic mechanisms underlying dry eye disease. Evidence was evaluated concerning the tear film, lacrimal gland and accessory lacrimal glands, ocular surface epithelia (including cornea and conjunctiva), meibomian glands, lacrimal duct system and the immune system. Consideration was given to both animal and human research data. Results are presented as a series of information matrices, identifying what is known and providing supporting references. An attempt is made to identify areas for further investigation.

Overexpression of phosphorylated STAT-1alpha in the labial salivary glands of patients with Sjögren's syndrome

OBJECTIVE

To clarify the molecular mechanisms of Sjögren's syndrome (SS), we analyzed the functional role of the STAT-1 gene, one of the interferon-gamma (IFNgamma)-inducible genes, in labial salivary glands (LSGs) from SS patients.

METHODS

The expression of STAT-1 messenger RNA (mRNA) was examined by real-time polymerase chain reaction (PCR) analysis, and the phosphorylation of STAT-1 protein (Tyr(701) and Ser(727) pSTAT-1) was investigated by Western blot and immunohistochemical analyses. The expression of IFNgamma-inducible 10-kd protein (IP-10), IFN regulatory factor 1 (IRF-1), and Fas was also examined by real-time PCR and immunohistochemical analyses.

RESULTS

STAT-1alpha and STAT-1beta mRNA were highly expressed in LSGs from SS patients. The level of STAT-1alpha protein in SS LSGs was higher than that in 3 control LSGs, whereas STAT-1beta protein was not clearly detected by Western blot analysis. Moreover, Tyr(701) and Ser(727) pSTAT-1alpha proteins were specifically detected in SS LSGs. Immunohistochemical analysis showed localization of Tyr(701) pSTAT-1 in infiltrating lymphocytes and the adjacent ductal epithelium from SS patients. Ser(727) pSTAT-1 was localized only in the ductal epithelium of SS LSGs. The STAT-1-inducible genes IP-10 and IRF-1 and the Fas genes were highly expressed in SS LSGs and were colocalized with Ser(727) pSTAT-1-positive, but not Tyr(701) pSTAT-1-positive, cells.

CONCLUSION

We found evidence of the up-regulation of STAT-1alpha mRNA and protein in LSGs from SS patients, as well as the presence of pSTAT-1alpha in ductal epithelium from SS patients. Our findings suggest that STAT-1alpha, especially Ser(727) pSTAT-1, may function as a key molecule in the pathogenesis of SS.