Conjunctival Cells Research Articles

CRGD-Conjugated Bilirubin Nanoparticles Alleviate Dry Eye Disease Via Activating the PINK1-Mediated Mitophagy.

The purpose of this study was to evaluate the cytoprotective effect and the mechanism of cRGD-conjugated bilirubin nanoparticles (cNPs@BR) in dry eye disease (DED). The binding capacity and cellular uptake of cNPs@BR in human corneal epithelial cells (HCECs) were assessed by immunofluorescence. The anti-inflammation and anti-oxidative stress effects of cNPs@BR were determined by flow cytometry, immunofluorescence, Western blot, chromatin immunoprecipitation (ChIP), and ELISA assay in LPS-stimulated RAW264.7 cells and hypertonic HCECs. The function of ocular surface barrier, tear production, and the number of goblet cells after cNPs@BR treatment were further assessed by fluorescein sodium staining, phenol red cotton threads, quantitative PCR (qPCR), hematoxylin and eosin (H&E) staining, and Periodic Acid-Schiff (PAS) staining in a 0.2% BAC-induced DED mouse model. Furthermore, the mechanism of cNPs@BR in treating DED was explored by RNA sequencing and RNA interference. The cRGD peptide prolonged the retention time of nanoparticles on HCECs and enhanced the cellular uptake efficiency. In both cell models, 20 µM cNPs@BR pretreatment ameliorated oxidative stress by decreasing the intracellular reactive oxygen species (ROS) levels and the expression of NOX4 and 4-HNE, while promoting HO-1 and nuclear Nrf2 levels. Moreover, cNPs@BR alleviated the inflammatory response by inhibiting NF-κB p65 nuclear translocation and decreasing the expression of iNOS and the secretion of IL-1β, IL-6, and TNF-α. In addition, cNPs@BR protected ocular surface epithelium against oxidative stress and inflammation and restored conjunctival goblet cells in the mouse model of DED by activating PINK1-mediated mitophagy. The cNPs@BR suppressed oxidative stress and inflammatory response in the ocular surface epithelium and restored goblet cells by activating PINK1-mediated mitophagy.

CD46 Is a Protein Receptor for Human Adenovirus Type 64

Certain species D human adenoviruses (HAdV-D19, -D37, and -D64) are causative agents of epidemic keratoconjunctivitis. HAdV-D37 has previously been shown to bind CD46 (membrane cofactor protein) and sialic acid as adhesion receptors. HAdV-D64 is genetically highly similar to HAdV-D37, with an identical fiber protein sequence, but differs substantially in its penton base and hexon proteins, two other major capsid components, due to genetic recombination. Here, we demonstrate that, like HAdV-D37, HAdV-D64 virions bind directly to CD46 and that CD46 and sialic acid also function as receptors for HAdV-D64 on multiple cell types. Expression of CD46 on CD46-negative cells conferred susceptibility to HAdV-D64 entry. Specifically blocking HAdV-D64 binding to CD46 on the host cell surface strongly inhibits viral entry and gene delivery into multiple cell lines that represent target tissues. We show that CD46 is expressed on human conjunctival epithelial cells and directly binds to the HAdV-D64 virion. Our results suggest that HAdV-D64 may be used to deliver genes to target conjunctival cells and that interrupting HAdV-D64 entry through its interaction with CD46 may prevent or lessen adenovirus-associated ocular disease.

Postoperative dry eye following femtosecond laser-assisted cataract surgery: insights and preventive strategies.

Postoperative dry eye is a common complication following femtosecond laser-assisted cataract surgery, and the patient interface (PI) used during the procedure may play a significant role in its occurrence. This study, utilizing a meticulous scientific search strategy, identified seven relevant articles through literature search engines. Most of these studies employed contact-type PI during surgeries, while one researcher used a non-contact PI. All studies assessed dry eye symptoms at various postoperative periods using metrics such as the Ocular Surface Disease Index (OSDI), tear Break-Up Time (BUT), Schirmer I test (SIt), and so on. However, the findings were inconsistent. On this basis, this comprehensive review delves into the potential impact of different patient interfaces on corneal nerve damage and conjunctival goblet cell injury, possibly contributing to an increased risk of postoperative dry eye. The review also explores various preventive and solution strategies, including improving PI design, reducing surgical time, and utilizing tear protective agents. The findings highlight the importance of optimizing the PI to minimize the risk of postoperative dry eye in femtosecond laser-assisted cataract surgery.

Enrichment protocols for human conjunctival extracellular vesicles and their characterization

The understanding of the role played by extracellular vesicles (EVs) in different tissues has improved significantly in the last years, but remains limited concerning the conjunctiva, a complex eye tissue whose role is pivotal for corneal protection. Here, we conducted a comparative study to isolate and characterize EVs from human conjunctival epithelial (IM-HConEpiC) and human conjunctival mesenchymal stromal cell (Conj-MSCs) secretomes using different isolation methods: differential ultracentrifugation (UC), and a combination of ultrafiltration (UF) with precipitation or size exclusion chromatography (SEC). EVs were characterized by total protein content, size, morphology, and expression of protein markers. EV functional effect was tested in an in vitro oxidative stress model. We successfully recovered EVs with the three methods, although significantly higher yields were obtained with UF-precipitation. Dynamic light scattering analysis confirmed the presence of nano-sized particles, being UC-isolated EVs larger than those isolated by UF-precipitation and UF-SEC. Atomic Force Microscopy showed EVs with a slightly ellipsoidal morphology. EVs enriched with UF-precipitation method were further analyzed, confirming the expression of Alix, CD63, TSG101, and Syntenin-1 by Western blotting and showing that Conj-MSC-derived EVs significantly reduced oxidative stress on IM-HConEpiC. Therefore, we conclude that UF-precipitation is the most efficient method for conjunctival EV enrichment.

Exosomes from Limosilactobacillus fermentum Ameliorate Benzalkonium Chloride-Induced Inflammation in Conjunctival Cells.

Dry eye is characterized by persistent instability and decreased tear production, which are accompanied by epithelial lesions and inflammation on the surface of the eye. In our previous paper, we reported that supplementation with Limosilactobacillus fermentum HY7302 (HY7302) could inhibit corneal damage in a benzalkonium chloride (BAC)-induced mouse model of dry eye, through its effects in gut microbiome regulation. The aim of this study was to determine what functional extracellular substances can alter the inflammatory response of conjunctival cells. We isolated exosomes from HY7302 probiotic culture supernatant, analyzed their morphological characteristics, and found that their average size was 143.8 ± 1.1 nm, which was smaller than the exosomes from the L. fermentum KCTC 3112 strain. In addition, HY7302-derived exosomes significantly reduced the levels of genes encoding pro-inflammatory cytokines, including interleukin (IL)-20, IL-8, IL-6, and IL-1B, in BAC-treated human conjunctival cells. Moreover, HY7302-derived exosomes significantly increased the levels of genes encoding tight junction proteins, including TJP1, TJP2, and occludin-1, in Caco-2 cells. Lastly, the HY7302 exosomes reduced mRNA expression levels of IL1B, IL20, IL6, IL8, and NFAT5 in a transwell coculture system. Our findings indicate that HY7302 exosomes have potential for use in the treatment of ocular inflammation-related dry eye disease, through gut-eye axis communication via exosomes.

Evaluation of ocular surface inflammation and systemic conditions in patients with systemic lupus erythematosus: a cross-sectional study

ObjectiveThe cross-sectional study was designed to evaluate the association of ocular surface inflammation with systemic conditions in patients with systemic lupus erythematosus (SLE).MethodsThe study enrolled 30 SLE patients and 30 controls. Ocular symptoms were evaluated using the Ocular Surface Disease Index (OSDI) questionnaire. Tear samples from all participants were collected for tear multi-cytokine and chemokine concentration analysis. All participants were assessed for dry eye disease (DED), including Schirmer I test, tear break-up time (TBUT), corneal fluorescein staining (CFS), meibomian gland secretion (MGS), lid-parallel conjunctival folds (LIPCOF), corneal clarity, and symblepharon. Besides, all participants were also examined for conjunctival impression cytology to measure the density of conjunctival goblet cells (CGCs). The peripheral blood indicators from SLE patients were also collected to measure the SLE-associated autoantibody specificities and systemic inflammatory indicators. Pearson and Spearman’s analysis were uesd to examine the correlation between tear cytokines, CGCs, DED-related indicators, and systemic conditions.ResultsThe two groups were matched for age and gender in this study. 36.67% of eyes (11 in 30) of SLE patients and 13.33% of eyes (4 in 30) of controls were diagnosed with DED. OSDI scores, abnormal TBUT percentages, CFS percentages, and DED grading were all higher in SLE patients than in control group, while density of CGCs was lower. There were no significant differences in Schirmer I test, MGS, LIPCOF, corneal clarity, and symblepharon between SLE patients and controls. The levels of tear chemokine (C-X-C motif) ligand 11 (CXCL11) and cytokine interleukin-7 (IL-7) in patients with SLE were significantly higher than those in control group. Moreover, among SLE patients, the severity of DED and the level of tear chemokine CXCL11 were significantly positively correlated with SLE-associated autoantibody specificities.ConclusionDry eye and tear cytokines and chemokines-mediated ocular surface inflammation persist in SLE patients and are associated with systemic conditions. Therefore, it is necessary for patients with SLE to combine systemic and ocular assessments.

Effect of carbon black and silicon dioxide nanoparticle exposure on corona receptor ACE2 and TMPRSS2 expression in the ocular surface

The Coronavirus disease 2019 (COVID-19) pandemic has led to a global health crisis, including ocular symptoms, primarily targeting the Angiotensin-Converting Enzyme 2 (ACE2) receptor. PM2.5 air pollution may increase infection risk by altering ACE2 expression. Silicon Dioxide (SiO2) and carbon black (CB), major components of PM2.5 from sands and vehicle emissions, were studied for their effects on ACE2 and Transmembrane Protease Serine 2 (TMPRSS2) expression in corneal and conjunctival cells, and ocular tissues. Human corneal epithelial cells (HCECs) and conjunctival epithelial cells (HCjECs) were exposed to nanoparticles (NPs) for 24 hours, assessing viability via WST-8 assay. TNF-α, IL-6, and IL-1β levels in the medium were measured. An in vivo rat study administered NPs via eye drops, with Rose Bengal staining to evaluate damage. ACE2, TMPRSS2, and Angiotensin II (AngII) protein expressions were quantified by Western blot. ACE2 expression in HCjECs increased with NP exposure, while it decreased in HCECs. CB exposure increased TNF-α, IL-6, and IL-1β levels in HCECs. In vivo, corneal exposure to CB decreased ACE2 expression, whereas conjunctival exposure to SiO2 increased ACE2 expression. These changes suggest that SiO2 exposure may increase the risk of COVID-19 through the ocular surface, while CB exposure may decrease it.

Biomimetic Curcumin-Loaded Liposomes for the Treatment of Dry Eyes and Meibomian Gland Dysfunction: An In Vivo Study.

Background/Objectives: Meibomian gland dysfunction (MGD) and dry eye syndrome (DES) are common eye diseases characterized by altered tear film stability and inflammation of the ocular surface, causing significant discomfort and possible visual impairment. This study aimed to investigate the efficacy of curcumin-loaded liposomes (Lipo@Cur) compared to cyclosporine A-loaded liposomes (Lipo@CycA) in experimental rabbit models of MGD and DES, with a focus on their ability to improve tear film stability and reduce ocular surface inflammation. Methods: MGD and DES were induced using complete Freund's adjuvant (CFA) and treated to evaluate the effect of liposomal formulations on tear break-up time (TBUT), clinical signs of inflammation (telangiectasia, conjunctival hyperemia, meibomian foramen occlusion), and corneal as well as conjunctival histological cells. Results: Lipo@Cur increased TBUT and reduced the signs of ocular surface inflammation, potentially approaching the effectiveness of clinically approved cyclosporine A encapsulated in liposomes (Lipo@CycA). Histological analysis suggested improvements in corneal epithelial thickness and goblet cell density in the treated groups, which may indicate a reversal of DES-induced damage to the ocular surface. Conclusions: Plant-originated curcumin encapsulated in liposomes offers a promising therapeutic strategy for the management of MGD and DES that may improve patient outcomes by addressing the underlying inflammatory mechanisms of these conditions.

A Comprehensive Review about Risks of Type-II Diabetes on Ocular Tear Film

Millions of people worldwide suffer from diabetes mellitus (DM), which can lead to systemic issues in a number of organs. Ocular problems, such as dry eye syndrome (DES), are among its less well-known side effects. This review delves into the interactions between diabetes and the composition of tear films, emphasizing alterations in the mucin, aqueous and lipid layer. Dry eye symptoms are exacerbated by induced changes in the components of the tear film in diabetes DM, which lead in decrement in tear production, increment in tear evaporation and tear film instability. Lipid layer is a lubricant, that reduces friction between the ocular surface and the eyelids which promotes high-quality, smooth refractive surface. The lacrimal function unit shields the tear film, preserves the normal function of the ocular surface. The mucin layer is secreted by the conjunctival goblet cells, in hyperglycemia the functionality of the cells are reduced thus, the mucin secretion is also altered which causes instability of the tear film. Diabetic patients can have their tear film integrity assessed with the help of diagnostic methods like Schirmer's Test and Tear Break- Up Time (TBUT). In order to relieve symptoms and maintain ocular health, there should be a complete management of diabetes and the induced tear film disorders.

Efficacy of Topical Cyclosporine Combined with Punctal Plugs in Treating Dry Eye Disease and Inflammation

Purpose To evaluate the effect of punctal plugs combined with cyclosporine eye drops on dry eye disease (DED) and ocular surface inflammation. Methods In a clinical trial, 73 patients were randomly allocated into three groups: punctal plug group, combination therapy group, and cyclosporine group. At the baseline and four weeks after treatment, the Schirmer I test score, fluorescein tear film break-up time (FBUT), ocular surface staining score and dry eye symptoms were assessed. Tear samples were collected to detect the level of inflammatory factors (interleukins, matrix metalloproteinase 9 (MMP-9) and tumor necrosis factor alpha (TNF-α)). In an animal experiment, a New Zealand rabbit dry eye model was induced. The rabbits were randomly divided into control group, punctal plug group, and combination therapy group (n = 6). Conjunctival goblet cell density, protein level of MMP-9 in conjunctiva and mRNA levels of inflammatory factors in conjunctiva and cornea were measured before and after treatment. Results In combination therapy group of the clinical trial, the following results were observed: significant improvement in Schirmer I test scores and FBUT compared to the cyclosporine group and punctal plug group, respectively; a decrease in the tear levels of IL-6, IL-1, and MMP-9 compared to the punctal plug group; and a decrease in the tear levels of IL-1α, IL-6, and IL-17 compared to the baseline (all p < 0.05). In the animal experiment, rabbits in combination therapy group had a higher goblet cell density (p < 0.01) and lower mRNA levels of IL-16 (p < 0.05), IL-17 (p < 0.05), and MMP-9 (p < 0.01) in conjunctiva and that of MMP-9 (p < 0.01) in cornea compared to punctal plug group. Conclusion Cyclosporine eye drops combined with degradable punctal plugs is a more optimized clinical treatment strategy for DED compared with degradable punctal plugs or cyclosporine eye drops alone, considering the influence of comprehensive clinical efficacy and ocular surface inflammation.

IL-37 Inhibits Inflammation of Lacrimal Gland in Dry Eye Mice via the IL-37-PTEN-NFκB Signaling Pathway

ABSTRACT Purpose This study aims to investigate the role of Interleukin-37 (IL-37) in mouse models of dry eye. Methods Two murine models of dry eye were employed in this investigation. The evaluation of the anti-inflammatory impact of IL-37 (200 μl, 10 μg/ml) on dry eye mice involved intraperitoneal injections administered once daily for 7 days. Additionally, intraperitoneal injection of VO-Ohpic trihydrate (VO, 0.25 mg/kg) in dry eye mice was performed to investigate the role of PTEN in the IL-37 anti-inflammatory signaling pathway. Tear production was assessed using phenol red cotton thread, while corneal damage was examined through sodium fluorescein staining using a slit lamp. Histological alterations in the lacrimal gland were observed through H&E staining. PAS staining was used to assess conjunctival goblet cells. The levels of NFκB-P65, p-NFκB-P65, IL-1β, IL-6, TNF-α, CD3, AQP5, α-SMA and PTEN proteins were determined via Western blotting or immunofluorescence. Results Following IL-37 treatment, both dry eye models exhibited reduced corneal fluorescence staining scores and enhanced tear production. In lacrimal gland, the expression of p-NFκB-P65, IL-1β, IL-6, CD3 and TNF-α was diminished, while PTEN, AQP5, α-SMA expression increased after IL-37 treatment in both dry eye mice. However, the intraperitoneal injection of VO significantly attenuated the anti-inflammatory effect of IL-37 on dry eye mice. Conclusion IL-37 emerges as an anti-inflammatory mediator within the lacrimal gland of dry eye mice, exerting its effects through the IL-37-PTEN-NFκB signaling pathway.

Development of human amniotic epithelial cell-derived extracellular vesicles as cell-free therapy for dry eye disease

PurposeThis study aimed to investigate the therapeutic potential of extracellular vesicles (EVs) derived from human amniotic epithelial cells (hAEC-EVs) for Dry Eye Disease (DED) treatment. MethodsHighly purified EVs were isolated from the culture supernatants of hAECs, which obtained from term placenta and characterized. Proteomic contents were analyzed for assessing its biological function related to the therapeutic potentials for DED. Subsequently, we examined the therapeutic efficacy of hAEC-EVs on human corneal epithelial cells exposed to hyperosmotic stress and in an experimental DED mouse model induced by desiccation stress. ResultsProteomic analysis of hAEC-EVs revealed proteins linked to cell proliferation and anti-inflammatory responses. We demonstrated efficient uptake of hAEC-EVs by ocular surface cells. Under DED conditions, EV treatment increased corneal epithelial cell proliferation and migration, and concurrently reducing inflammatory cytokines. In the DED mouse model, hAEC-EVs showed significant improvements in corneal staining score, tear secretion, corneal irregularity, and conjunctival goblet cell density. Additionally, hAEC-EVs exhibited a mitigating effect on ocular surface inflammation induced by desiccation. ConclusionsThese findings suggest that hAEC-EVs hold potential as a cell-free therapy for corneal epithelial defects and ocular surface diseases, presenting a promising treatment option for DED.

Changes in conjunctival mononuclear phagocytes and suppressive activity of regulatory macrophages in desiccation induced dry eye

PurposeTo evaluate the effects of dry eye on conjunctival immune cell number and transcriptional profiles with attention to mononuclear phagocytes. MethodsExpression profiling was performed by single-cell RNA sequencing on sorted conjunctival immune cells from non-stressed and C57BL/6 mice subjected to desiccating stress (DS). Monocle 3 modeled cell trajectory, scATAC-seq assessed chromatin accessibility and IPA identified canonical pathways. Inflammation and goblet cells were measured after depletion of MRC1+ MΦs with mannosylated clodronate liposomes. ResultsMononuclear phagocytes (monocytes, MΦs, DCs) comprised 72 % of immune cells and showed the greatest changes with DS. Distinct DS induced gene expression patterns were seen in phagocytes classified by expression of Ccr2 and [Timd4, Lyve1, Folr2 (TLR)]. Expression of phagocytosis/efferocytosis genes increased in TLF+CCR2- MΦs. Monocytes showed the highest expression of Ace, Cx3cr1, Vegfa, Ifngr1,2, and Stat1 and TLF−CCR2+ cells expressed higher levels of inflammatory mediators (Il1a, Il1b, Il1rn, Nfkb1, Ccl5, MHCII, Cd80, Cxcl10, Icam1). A trajectory from monocyte precursors branched to terminate in regulatory MΦs or in mDCs via transitional MΦ and cDC clusters. Activated pathways in TLF+ cells include phagocytosis, PPAR/RXRα activation, IL-10 signaling, alternate MΦ activation, while inflammatory pathways were suppressed. Depletion of MRC1+ MΦs increased IL-17 and IFN-γ expression and cytokine-expressing T cells, reduced IL-10 and worsened goblet loss. ConclusionsDryness stimulates distinct gene expression patterns in conjunctival phagocytes, increasing expression of regulatory genes in TLF+ cells regulated in part by RXRα, and inflammatory genes in CCR2+ cells. Regulatory MΦs depletion worsens DS induced inflammation and goblet cell loss.

Sex-dependent differential increase of specialized pro-resolving mediators in extracellular vesicles secreted by human primary conjunctival goblet cells during allergic inflammation

AimsConjunctival epithelium lines the inside of the eyelids and covers the sclera, thus providing stability to the eye surface. Goblet cells in conjunctival epithelium (CjGCs) are well known for their mucin-secretion function, which wet and protect the ocular surface, but other aspects are still not well understood. To expand our understanding beyond their mucin-secreting function, we investigated CjGC-secreted extracellular vesicles (EVs) and lipid mediators therein. Materials and methodsUsing histamine-mediated allergic inflammation in human primary CjGCs (HCjGCs) as a disease model, we quantified using ELISA a proinflammatory mediator PGE2 and two specialized pro-resolving mediators (SPMs) LXA4 and RvD1 in EVs secreted during allergic inflammation. Key findingsAt 18 h post histamine stimulation, the amount of LXA4 and RvD1 in EVs was notably higher compared to those in unstimulated. Interestingly, this increase was only observed in female EVs but not in males. The mean fold increase of LXA4 and RvD1 in female EVs was 3.9 and 3.4, respectively, but it was only 0.9 and 1.0 in male EVs. Supplying docosahexaenoic acid (DHA, the source of RvD1 and other SPMs) to the culture medium during the allergic inflammation resulted in even higher mean fold increase of 5.3 and 6.9 for LXA4 and RvD1 in female EVs, respectively, but it was only 0.5 and 0.8 in male EVs. SignificanceWe conclude that HCjGCs show a clear sex difference in allergic response. Our results may also provide a new insight into the male predisposition to severe forms of allergic conjunctivitis and potential improvement in disease care in the clinic.

Superficial Conjunctival Cells from Dupilumab-Treated Patients with Atopic Dermatitis with Ocular Adverse Events Display a Transcriptomic Psoriasis Signature

Dupilumab has demonstrated efficacy in the treatment of atopic dermatitis. However, a subset of patients experiences ocular adverse events (OAEs), including conjunctivitis and dry eye syndrome, the pathological mechanisms of which are still unknown. In a bicentric study, we used DNA microarray analysis to compare the transcriptome of conjunctival cells of patients with atopic dermatitis collected by impression cytology before (M0) and 4 months after (M4) initiating dupilumab treatment. Thirty-six patients were included and divided in 2 groups according to their ophthalmological status at M4: 12 with OAEs (OAE+) and 24 without (OAE-). The analysis revealed 52 differentially expressed genes between OAE+ and OAE- patients at M0 and 113 at M4. Ingenuity Pathway Analysis enrichment revealed a psoriasis signature in OAE+ patients, both before and after OAE outcomes. In addition, we noticed the overexpression of several genes involved in keratinocyte differentiation, particularly encoding cornified envelope components. Among the 16 differentially expressed genes selected for real-time RT-PCR validation, 9 were confirmed as upregulated at M4 in OAE+ versus OAE- patients, validating the psoriasis signature, whereas MUC7 was downregulated. In conclusion, these results suggest that a conjunctival transcriptomic profile predisposes some patients with atopic dermatitis to developing OAEs upon dupilumab treatment.

Directed differentiation of human embryonic stem cells into conjunctival epithelial cells

Severe conjunctival damage can lead to extensive ocular cicatrisation, fornix shortening, and even ocular surface failure, resulting in significant vision impairment. Conjunctival reconstruction is the primary therapeutic strategy for these clinical conjunctival diseases. However, there have been limited studies on induced differentiation of conjunctival epithelial cells derived from stem cells. In this study, we established a chemical defined differentiation protocol from human embryonic stem cells (hESCs) into conjunctival epithelial cells. hES cell line H1 was used for differentiation, and RT-qPCR, immunofluorescence staining, Periodic-acid-Schiff staining (PAS), and transcriptome analysis were employed to identify the differentiated cells. Here, to imitate the development of the vertebrate conjunctiva, hESCs were induced using a three-step process involving first chetomin was used to induce ocular surface ectoderm, then nicotinamide was used to induce ocular surface epithelial progenitor cells, and finally epidermal growth factor, keratinocyte growth factor and other factors were used to differentiate mature conjunctival epithelial cells. hESC-derived conjunctival epithelial cells expressed mature conjunctival epithelial lineage markers (including PAX6, P63, K13). The presence of goblet cells was confirmed by positive PAS. Transcriptome analysis revealed that hESC-derived conjunctival epithelial cells possessed a more naïve phenotype, and exhibited greater proliferation capacity compared to mature human conjunctival epithelial cells, suggesting their potential as alternative seed cells for conjunctival reconstruction.

Possible Correlation between Mucin Gene Expression and Symptoms of Dry Eye Syndrome Secondary to Sjogren’s Disease

(1) Background: It is estimated that 10% of dry eye disease (DED) occurs in patients with Sjogren’s syndrome (SS-DED) and represents a challenge when it comes to treatment. Both innate and adaptive immunity participate in the pathogenesis of SS-DED. Previous studies suggest that Th1 and Th17 cell immune responses are the main actors associated with the pathogenesis of this disease. Ocular surface mucins play a fundamental role in ocular surface homeostasis. In particular, the main transmembrane mucins, MUC1, MUC4 and MUC16, are dysregulated in DED and could be involved in the activation of pro-inflammatory cytokines at the ocular interface. Thus, the objective of this work was to analyze mucin and cytokine expression in ocular surface (OS) damage and correlate it with clinical symptoms.; (2) Methods: 18 patients with SS-DED and 15 healthy controls were included in the study. Samples of conjunctival cells were obtained through cytology impression. RNA was extracted from the collected samples and used to determine the expression of MUC1, 4 and 16 by qRT-PCR. Pro-inflammatory cytokines associated with DED pathogenesis (IL17 and IL-22) were also evaluated. The results were contrasted with the clinical findings on examination of the patients. (3) Results: We observed a significant increase in the expression of MUC1 and MUC4 in patients with SS-DED. MUC4 significantly correlated with both lower production and stability of the tear film, as well as greater superficial keratopathy. On the other hand, MUC1 and MUC16 were positively correlated with the presence of more severe DED symptoms. However, we could not reproduce an increase in IL-17 and IL-22 in DED patients as previously reported; (4) Conclusions: This work constitutes an approach to understanding how the gene expression of transmembrane mucins associates with SS-DED symptoms and clinical signs.

Complement Component C5a and Fungal Pathogen Induce Diverse Responses through Crosstalk between Transient Receptor Potential Channel (TRPs) Subtypes in Human Conjunctival Epithelial Cells.

The conjunctiva has immune-responsive properties to protect the eye from infections. Its innate immune system reacts against external pathogens, such as fungi. The complement factor C5a is an important contributor to the initial immune response. It is known that activation of transient-receptor-potential-vanilloid 1 (TRPV1) and TRP-melastatin 8 (TRPM8) channels is involved in different immune reactions and inflammation in the human body. The aim of this study was to determine if C5a and mucor racemosus e voluminae cellulae (MR) modulate Ca2+-signaling through changes in TRPs activity in human conjunctival epithelial cells (HCjECs). Furthermore, crosstalk was examined between C5a and MR in mediating calcium regulation. Intracellular Ca2+-concentration ([Ca2+]i) was measured by fluorescence calcium imaging, and whole-cell currents were recorded using the planar-patch-clamp technique. MR was used as a purified extract. Application of C5a (0.05-50 ng/mL) increased both [Ca2+]i and whole-cell currents, which were suppressed by either the TRPV1-blocker AMG 9810 or the TRPM8-blocker AMTB (both 20 µM). The N-terminal peptide C5L2p (20-50 ng/mL) blocked rises in [Ca2+]i induced by C5a. Moreover, the MR-induced rise in Ca2+-influx was suppressed by AMG 9810 and AMTB, as well as 0.05 ng/mL C5a. In conclusion, crosstalk between C5a and MR controls human conjunctival cell function through modulating interactions between TRPV1 and TRPM8 channel activity.

Purinergic agonists increase [Ca2+]i in rat conjunctival goblet cells through ryanodine receptor type 3.

ATP and benzoylbenzoyl-ATP (BzATP) increase free cytosolic Ca2+ concentration ([Ca2+]i) in conjunctival goblet cells (CGCs) resulting in mucin secretion. The purpose of this study was to investigate the source of the Ca2+i mobilized by ATP and BzATP. First-passage cultured rat CGCs were incubated with Fura-2/AM, and [Ca2+]i was measured under several conditions with ATP and BzATP stimulation. The following conditions were used: 1) preincubation with the Ca2+ chelator EGTA, 2) preincubation with the SERCA inhibitor thapsigargin (10-6 M), which depletes ER Ca2+ stores, 3) preincubation with phospholipase C (PLC) or protein kinase A (PKA) inhibitor, or 4) preincubation with the voltage-gated calcium channel antagonist nifedipine (10-5 M) and the ryanodine receptor (RyR) antagonist dantrolene (10-5 M). Immunofluorescence microscopy (IF) and quantitative reverse transcription polymerase chain reaction (RT-qPCR) were used to investigate RyR presence in rat and human CGCs. ATP-stimulated peak [Ca2+]i was significantly lower after chelating Ca2+i with 2 mM EGTA in Ca2+-free buffer. The peak [Ca2+]i increase in CGCs preincubated with thapsigargin, the PKA inhibitor H89, nifedipine, and dantrolene, but not the PLC inhibitor, was reduced for ATP at 10-5 M and BzATP at 10-4 M. Incubating CGCs with dantrolene alone decreased [Ca2+]i and induced CGC cell death at a high concentration. RyR3 was detected in rat and human CGCs with IF and RT-qPCR. We conclude that ATP- and BzATP-induced Ca2+i increases originate from the ER and that RyR3 may be an essential regulator of CGC [Ca2+]i. This study contributes to the understanding of diseases arising from defective Ca2+ signaling in nonexcitable cells.NEW & NOTEWORTHY ATP and benzoylbenzoyl-ATP (BzATP) induce mucin secretion through an increase in free cytosolic calcium concentration ([Ca2+]i) in conjunctival goblet cells (CGCs). The mechanisms through which ATP and BzATP increase [Ca2+]i in CGCs are unclear. Ryanodine receptors (RyRs) are fundamental in [Ca2+]i regulation in excitable cells. Herein, we find that ATP and BzATP increase [Ca2+]i through the activation of protein kinase A, voltage-gated calcium channels, and RyRs, and that RyRs are crucial for nonexcitable CGCs' Ca2+i homeostasis.

Multimodal mucosal and systemic immune characterization of a non-human primate trachoma model highlights the critical role of local immunity during acute phase disease.

Trachoma is a leading cause of infection-related blindness worldwide. This disease is caused by recurrent Chlamydia trachomatis (Ct) infections of the conjunctiva and develops in two phases: i) active (acute trachoma, characterized by follicular conjunctivitis), then long-term: ii) scarring (chronic trachoma, characterized by conjunctival fibrosis, corneal opacification and eyelid malposition). Scarring trachoma is driven by the number and severity of reinfections. The immune system plays a pivotal role in trachoma including exacerbation of the disease. Hence the immune system may also be key to developing a trachoma vaccine. Therefore, we characterized clinical and local immune response kinetics in a non-human primate model of acute conjunctival Ct infection and disease. The conjunctiva of non-human primate (NHP, Cynomolgus monkeys-Macaca fascicularis-) were inoculated with Ct (B/Tunis-864 strain, B serovar). Clinical ocular monitoring was performed using a standardized photographic grading system, and local immune responses were assessed using multi-parameter flow cytometry of conjunctival cells, tear fluid cytokines, immunoglobulins, and Ct quantification. Clinical findings were similar to those observed during acute trachoma in humans, with the development of typical follicular conjunctivitis from the 4th week post-exposure to the 11th week. Immunologic analysis indicated an early phase influx of T cells in the conjunctiva and elevated interleukins 4, 8, and 5, followed by a late phase monocytic influx accompanied with a decrease in other immune cells, and tear fluid cytokines returning to initial levels. Our NHP model accurately reproduces the clinical signs of acute trachoma, allowing for an accurate assessment of the local immune responses in infected eyes. A progressive immune response occurred for weeks after exposure to Ct, which subsided into a persistent innate immune response. An understanding of these local responses is the first step towards using the model to assess new vaccine and therapeutic strategies for disease prevention.