The role of chemokines and their receptors in ocular disease

scHyper: reconstructing cell-cell communication through hypergraph neural networks

Cell-cell communications is crucial for the regulation of cellular life and the establishment of cellular relationships. Most approaches of inferring intercellular communications from single-cell RNA sequencing (scRNA-seq) data lack a comprehensive global network view of multilayered communications. In this context, we propose scHyper, a new method that can infer intercellular communications from a global network perspective and identify the potential impact of all cells, ligand, and receptor expression on the communication score. scHyper designed a new way to represent tripartite relationships, by extracting a heterogeneous hypergraph that includes the source (ligand expression), the target (receptor expression), and the relevant ligand-receptor (L-R) pairs. scHyper is based on hypergraph representation learning, which measures the degree of match between the intrinsic attributes (static embeddings) of nodes and their observed behaviors (dynamic embeddings) in the context (hyperedges), quantifies the probability of forming hyperedges, and thus reconstructs the cell-cell communication score. Additionally, to effectively mine the key mechanisms of signal transmission, we collect a rich dataset of multisubunit complex L-R pairs and propose a nonparametric test to determine significant intercellular communications. Comparing with other tools indicates that scHyper exhibits superior performance and functionality. Experimental results on the human tumor microenvironment and immune cells demonstrate that scHyper offers reliable and unique capabilities for analyzing intercellular communication networks. Therefore, we introduced an effective strategy that can build high-order interaction patterns, surpassing the limitations of most methods that can only handle low-order interactions, thus more accurately interpreting the complexity of intercellular communications.

Peripheral inflammation as a potential mechanism and preventive strategy for perioperative neurocognitive disorder under general anesthesia and surgery

General anesthesia, as a commonly used medical intervention, has been widely applied during surgical procedures to ensure rapid loss of consciousness and pain relief for patients. However, recent research suggests that general anesthesia may be associated with the occurrence of perioperative neurocognitive disorder (PND). PND is characterized by a decline in cognitive function after surgery, including impairments in attention, memory, learning, and executive functions. With the increasing trend of population aging, the burden of PND on patients and society's health and economy is becoming more evident. Currently, the clinical consensus tends to believe that peripheral inflammation is involved in the pathogenesis of PND, providing strong support for further investigating the mechanisms and prevention of PND.

Evaluation of expression pattern of cellular miRNAs (let-7b, miR-29a, miR-126, miR-34a, miR-181a-5p) and IL-6, TNF-α, and TGF-β in patients with pseudoexfoliation syndrome

Pseudoexfoliation syndrome (PEX) is a critical clinical and biological extracellular matrix systemic disorder. Despite the unknown nature of PEX etiopathogenesis, it is proven to be associated with various genes and factors. The present research focused on analyzing the expression of miR and inflammatory cytokines in PEX. Serum and aqueous humor (AH) were collected prior to cataract surgery or trabeculectomy from 99 participants (64 with PEX glaucoma, and 35 controls). Real-time PCR was used for assessing the expression pattern of some miRNAs namely let-7b, miR-29a, miR-126, miR-34a, and miR-181a-5p. ELISA was carried out to explore the transcription of some inflammatory cytokines such as TGF-β, TNF-α, and IL-6. The indication of our results was a significant enhancement in the expression of let-7, miR-34a, and miR-181a-5p in PEX in contrast to the control group. Notwithstanding a significant suppression in miR-29a, and miR-126 expression levels in PEX in contrast to the control group. Analysis of ROC curve revealed that miR-29a and miR-34a are able to act as useful markers in order to discriminate the PEX group from the PEX negative subjects which were determined as the control group. According to the results obtained, the mean levels of TGF-β, TNF-α, and IL-6 upregulated among PEX subjects in contrast to control samples. In conclusion, our findings indicated that the selected cytokines alongside the selected miRNAs could be introduced as a biomarker panel in the diagnosis of PEX.

Inhibition of NOX4 with GLX351322 alleviates acute ocular hypertension-induced retinal inflammation and injury by suppressing ROS mediated redox-sensitive factors activation

Reactive oxygen species (ROS) overproduction plays an essential role in the etiology of ischemic/hypoxic retinopathy caused by acute glaucoma. NADPH oxidase (NOX) 4 was discovered as one of the main sources of ROS in glaucoma. However, the role and potential mechanisms of NOX4 in acute glaucoma have not been fully elucidated. Therefore, the current study aims to investigate the NOX4 inhibitor GLX351322 that targets NOX4 inhibition in acute ocular hypertension (AOH)-induced retinal ischemia/hypoxia injury in mice. Herein, NOX4 was highly expressed in AOH retinas, particularly the retinal ganglion cell layer (GCL). Importantly, the NOX4 inhibitor GLX351322 reduced ROS overproduction, inhibited inflammatory factor release, suppressed glial cell activation and hyperplasia, inhibited leukocyte infiltration, reduced retinal cell senescence and apoptosis in damaged areas, reduced retinal degeneration and improved retinal function. This neuroprotective effect is at least partially associated with mediated redox-sensitive factor (HIF-1α, NF-κB, and MAPKs) pathways by NOX4-derived ROS overproduction. These results suggest that inhibition of NOX4 with GLX351322 attenuated AOH-induced retinal inflammation, cellular senescence, and apoptosis by inhibiting the activation of the redox-sensitive factor pathway mediated by ROS overproduction, thereby protecting retinal structure and function. Targeted inhibition of NOX4 is expected to be a new idea in the treatment of acute glaucoma.

A2Ar-dependent PD-1+ and TIGIT+ Treg cells have distinct homing requirements to suppress autoimmune uveitis in mice

The proper function of regulatory T cells (Tregs) to suppress inflammation requires homing to the correct tissue site. Resolution of autoimmune uveitis generates distinct programmed death receptor 1 (PD-1+) and T-cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domains (TIGIT+) Tregs in an adenosine 2A receptor (A2Ar)-dependent manner found in the spleen. Where and how these Tregs migrate from the spleen to prevent uveitis is not known. In this work, we show that A2Ar-dependent Tregs migrated to the eye and secondary lymphoid tissue and expressed chemokine receptor (CCR)6 and CCR7. Suppression of autoimmune uveitis required CCR6 and CCR7 expression for TIGIT+ Tregs but not PD-1+ Tregs. Moreover, stimulation of A2Ar on T cells from patients showed a decreased capacity to induce TIGIT+ Tregs that expressed CCR6 or CCR7, and PD-1+ Treg that expressed CCR6. This work provides a mechanistic understanding of the homing requirements of each of these Treg populations. Importantly, this work is clinically relevant because patients with chronic autoimmune uveitis are unable to induce the Treg populations identified in mice that home to the target tissue.

Extracellular Vesicles as Biomarkers and Therapeutics for Inflammatory Eye Diseases

Extracellular vesicles (EVs) are a group of cell-derived membrane vesicles of varying sizes that can be secreted by most cells. Depending on the type of cell they are derived from, EVs may contain a variety of cargo including proteins, lipids, miRNA, and DNA. Functionally, EVs play important roles in physiological and pathological processes through intercellular communication. While there has already been significant literature on the involvement of EVs in neurological and cardiovascular disease as well as cancer, recent evidence suggests that EVs may also play a role in mediating inflammatory eye diseases. This paper summarizes current advancements in ocular EV research as well as new ways by which EVs may be utilized as novel biomarkers of or therapeutics for inflammatory eye diseases.

Synthetic high-density lipoprotein nanoparticles: Good things in small packages

Medicine has been a great beneficiary of the nanotechnology revolution. Nanotechnology involves the synthesis of functional materials with at least one size dimension between 1 and 100 nm. Advances in the field have enabled the synthesis of bio-nanoparticles that can interface with physiological systems to modulate fundamental cellular processes. One example of a diverse acting nanoparticle-based therapeutic is synthetic high-density lipoprotein (HDL) nanoparticles (NP), which have great potential for treating diseases of the ocular surface. Our group has developed a spherical HDL NP using a gold nanoparticle core. HDL NPs: (i) closely mimic the physical and chemical features of natural HDLs; (ii) contain apoA-I; (iii) bind with high-affinity to SR-B1, which is the major receptor through which HDL modulates cell cholesterol metabolism and controls the selective uptake of HDL cargo into cells; (iv) are non-toxic to cells and tissues; and (v) can be chemically engineered to display nearly any surface or core composition desired. With respect to the ocular surface, topical application of HDL NPs accelerates re-epithelization of the cornea following wounding, attenuates inflammation resulting from chemical burns and/or other stresses, and effectively delivers microRNAs with biological activity to corneal cells and tissues. HDL NPs will be the foundation of a new class of topical eye drops with great translational potential and exemplify the impact that nanoparticles can have in medicine.

SHP-1 suppresses endotoxin-induced uveitis by inhibiting the TAK1/JNK pathway

We investigated how Src-homology 2-domain phosphatase-1 (SHP-1) regulates the inflammatory response in endotoxin-induced uveitis (EIU), and the signalling pathways involved. One week after intravitreal injection of short hairpin RNA targeting SHP-1 or SHP-1 overexpression lentivirus in rats, we induced ocular inflammation with an intravitreal injection of lipopolysaccharide (LPS). We then assessed the extent of inflammation and performed full-field electroretinography. The concentrations and retinal expression of various inflammatory mediators were examined with enzyme-linked immunosorbent assays and Western blotting, respectively. SHP-1 overexpression and knockdown were induced in Müller cells to study the role of SHP-1 in the LPS-induced inflammatory response in vitro. Retinal SHP-1 expression was up-regulated by LPS. SHP-1 knockdown exacerbated LPS-induced retinal dysfunction and increased the levels of proinflammatory mediators in the retina, which was abrogated by a c-Jun N-terminal kinase (JNK) inhibitor (SP600125). SHP-1 overexpression had the opposite effects. In Müller cells, the LPS-induced inflammatory response was enhanced by SHP-1 knockdown and suppressed by SHP-1 overexpression. SHP-1 negatively regulated the activation of the transforming growth factor-β-activated kinase-1 (TAK1)/JNK pathway, but not the nuclear factor-κB pathway. These results indicate that SHP-1 represses EIU, at least in part, by inhibiting the TAK1/JNK pathway and suggest that SHP-1 is a potential therapeutic target for uveitis.

Hypercytokinemia in COVID-19: Tear cytokine profile in hospitalized COVID-19 patients

The aim of this study is to analyze the concentrations of cytokines in tear of hospitalized COVID-19 patients compared to healthy controls. Tear samples were obtained from 41 healthy controls and 62 COVID-19 patients. Twenty-seven cytokines were assessed: interleukin (IL)-1b, IL-1RA, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL9, IL-10, IL-12, IL-13, IL-15, IL-17, eotaxin, fibroblast growth factor basic, granulocyte colony-stimulating factor (G-CSF), granulocyte-monocyte colony-stimulating factor (GM-CSF), interferon (IFN)-γ, interferon gamma-induced protein, monocyte chemo-attractant protein-1, macrophage inflammatory protein (MIP)-1a, MIP-1b, platelet-derived growth factor (PDGF), regulated on activation normal T cell expressed and secreted, tumor necrosis factor-α and vascular endothelial growth factor (VEGF).
In tear samples of COVID-19 patients, an increase in IL-9, IL-15, G-CSF, GM-CSF, IFN-γ, PDGF and VEGF was observed, along with a decrease in eotaxin compared to the control group (p < 0.05). A poor correlation between IL-6 levels in tear and blood was found. IL-1RA and GM-CSF were significantly lower in severe patients and those who needed treatment targeting the immune system (p < 0.05). Tear cytokine levels corroborate the inflammatory nature of SARS-CoV-2.

Pathological roles of the homeostatic chemokine CXCL12

CXCL12 is a CXC chemokine that traditionally has been classified as a homeostatic chemokine. It contributes to physiological processes such as embryogenesis, hematopoiesis and angiogenesis. In contrast to these homeostatic functions, increased expression of CXCL12 in general, or of a specific CXCL12 splicing variant has been demonstrated in various pathologies. In addition to this increased or differential transcription of CXCL12, also upregulation of its receptors CXC chemokine receptor 4 (CXCR4) and atypical chemokine receptor 3 (ACKR3) contributes to the onset or progression of diseases. Moreover, posttranslational modification of CXCL12 during disease progression, through interaction with locally produced molecules or enzymes, also affects CXCL12 activity, adding further complexity. As CXCL12, CXCR4 and ACKR3 are broadly expressed, the number of pathologies wherein CXCL12 is involved is growing. In this review, the role of the CXCL12/CXCR4/ACKR3 axis will be discussed for the most prevalent pathologies. Administration of CXCL12-neutralizing antibodies or small-molecule antagonists of CXCR4 or ACKR3 delays disease onset or prevents disease progression in cancer, viral infections, inflammatory bowel diseases, rheumatoid arthritis and osteoarthritis, asthma and acute lung injury, amyotrophic lateral sclerosis and WHIM syndrome. On the other hand, CXCL12 has protective properties in Alzheimer's disease and multiple sclerosis, has a beneficial role in wound healing and has crucial homeostatic properties in general.

The atypical chemokine receptor-2 does not alter corneal graft survival but regulates early stage of corneal graft-induced lymphangiogenesis

Purpose

To re-evaluate the role of the atypical chemokine receptor-2 (ACKR2) in corneal graft rejection and investigate the effect of ACKR2 on inflammation-associated lymphangiogenesis using murine orthotopic corneal transplantation.

Methods

Corneal grafts were performed and evaluated in the settings of syngeneic, allogeneic and single antigen (HY-antigen) disparity pairings. Corneal vessels were quantified in whole mounts from WT, ACKR2^−/− and F4/80^−/−ACKR2^−/− mice that received syngeneic or allogeneic grafts using anti-CD31 and anti-Lyve-1 antibodies.

Results

Syngeneic corneal grafts in WT and ACKR2^−/− mice were 100% accepted. Fully histo-incompatible allogeneic grafts were rapidly rejected (100%) with similar tempo in both WT and ACKR2^−/− hosts. Around 50% of single-antigen (HY) disparity grafts rejected at a slow but similar tempo (60 days) in WT and ACKR2^−/− mice. Prior to grafting, F4/80^−/−ACKR2^−/− mice had lower baseline levels of limbal blood and lymphatic vessels compared to ACKR2^−/− mice. Syngeneic grafts, but not allogeneic grafts, in ACKR2^−/− and F4/80^−/−ACKR2^−/− mice induced higher levels of lymphatic sprouting and infiltration of Lyve-1⁺ cells during the early (3d) post-graft (pg) stage but lymphatic density was similar to WT grafted mice by 7d pg.

Conclusions

Our results indicate that the chemokine scavenger receptor, ACKR2, has no role to play in the survival of allogeneic grafts. A minor role in regulation of lymphangiogenesis in the early stage of wound healing in syngeneic grafts is suggested, but this effect is probably masked by the more pronounced lymphangiogenic inflammatory response in allogeneic grafts. No additional effect was observed with the deletion of the resident macrophage gene, F4/80.

Monocyte chemoattractant protein 1 and fractalkine play opposite roles in angiogenesis via recruitment of different macrophage subtypes

AIM

To explore the interaction between macrophages and chemokines [monocyte chemoattractant protein 1 (MCP-1/CCL2) and fractalkine/CX3CL1] and the effects of their interaction on neovascularization.

METHODS

Human peripheral blood mononuclear cells, donated by healthy volunteers, were separated and cultured in RPMI-1640 medium containing 10% fetal bovine serum, then induced into macrophages by stimulation with 30 µg/L granulocyte macrophage-colony stimulating factor (GM-CSF). The expression of CCR2 and/or CX3CR1 in the macrophages was examined using flow cytometry. Macrophages were then stimulated with recombinant human CCL2 (rh-CCL2) or recombinant human CX3CL1 (rh-CX3CL1). The expression of angiogenesis-related genes, including VEGF-A, THBS-1 and ADAMTS-1 were examined using real-time quantitative polymerase chain reaction (PCR). Supernatants from stimulated macrophages were used in an assay of human retinal endothelial cell (HREC) proliferation. Finally, stimulated macrophages were co-cultured with HREC in a migration assay.

RESULTS

The expression rate of CCR2 in macrophages stimulated by GM-CSF was 42%±1.9%. The expression rate of CX3CR1 was 71%±3.3%. Compared with vehicle-treated groups, gene expression of VEGF-A in the macrophages was greater in 150 mg/L CCL2-treated groups (P<0.05), while expression of THBS-1 and ADAMTS-1 was significantly lower (P<0.05). By contrast, compared with vehicle-treated groups, expression of VEGF-A in 150 mg/L CX3CL1-treated groups was significantly lower (P<0.05), while expression of THBS-1 and ADAMTS-1 was greater (P<0.05). Supernatants from CCL2 treated macrophages promoted proliferation of HREC (P<0.05), while supernatants from CX3CL1-treated macrophages inhibited the proliferation of HREC (P<0.05). HREC migration increased when co-cultured with CCL2-treated macrophages, but decreased with CX3CL1-treated macrophages (P<0.05).

CONCLUSION

CCL2 and CX3CL1 exert different effects in regulation of macrophage in expression of angiogenesis-related factors, including VEGF-A, THBS-1 and ADAMTS-1. Our findings suggest that CCL2 and CX3CL1 may be candidate proteins for further exploration of novel targets for treatment of ocular neovascularization.

Cytokines Produced in Response to Varicella-Zoster Virus Infection of ARPE-19 Cells Stimulate Lymphocyte Chemotaxis

Posterior uveitis is an ocular complication that can occur with reactivation of varicella-zoster virus (VZV). It may lead to loss of vision due to retinal detachment and chronic inflammation, which often causes more severe disease than the virus infection itself. To increase our understanding of the immune response, we infected the retinal pigment epithelial (RPE) cell line, ARPE-19, with cell-associated VZV and compared its response to that of the MeWo cell line using multiplex assays. We observed (1) a difference in the magnitude and kinetics of cytokine responses between the 2 cell types and (2) differential migration of CD4+ and CD8+ T cells towards these cytokines. Thus, our data provide information about the cytokine and lymphocytic responses to VZV infection of RPE cells, thereby providing a useful platform for future studies to address mechanisms underlying the immunopathology of VZV-associated posterior uveitis.

Neuro-psychopharmacological perspective of Orphan receptors of Rhodopsin (class A) family of G protein-coupled receptors

BACKGROUND

In the central nervous system (CNS), G protein-coupled receptors (GPCRs) are the most fruitful targets for neuropsychopharmacological drug development. Rhodopsin (class A) is the most studied class of GPCR and includes orphan receptors for which the endogenous ligand is not known or is unclear. Characterization of orphan GPCRs has proven to be challenging, and the production pace of GPCR-based drugs has been incredibly slow.

OBJECTIVE

Determination of the functions of these receptors may provide unexpected insight into physiological and neuropathological processes. Advances in various methods and techniques to investigate orphan receptors including in situ hybridization and knockdown/knockout (KD/KO) showed extensive expression of these receptors in the mammalian brain and unmasked their physiological and neuropathological roles. Due to these rapid progress and development, orphan GPCRs are rising as a new and promising class of drug targets for neurodegenerative diseases and psychiatric disorders.

CONCLUSION

This review presents a neuropsychopharmacological perspective of 26 orphan receptors of rhodopsin (class A) family, namely GPR3, GPR6, GPR12, GPR17, GPR26, GPR35, GPR39, GPR48, GPR49, GPR50, GPR52, GPR55, GPR61, GPR62, GPR63, GPR68, GPR75, GPR78, GPR83, GPR84, GPR85, GPR88, GPR153, GPR162, GPR171, and TAAR6. We discussed the expression of these receptors in mammalian brain and their physiological roles. Furthermore, we have briefly highlighted their roles in neurodegenerative diseases and psychiatric disorders including Alzheimer's disease, Parkinson's disease, neuroinflammation, inflammatory pain, bipolar and schizophrenic disorders, epilepsy, anxiety, and depression.

Glucocorticoid-induced leucine zipper overexpression inhibits lipopolysaccharide-induced retinal inflammation in rats

Glucocorticoid-induced leucine zipper (GILZ) mediates several effects of glucocorticoids and has important anti-inflammatory properties. Here, we explored the role of GILZ in inhibiting retinal inflammation. Endotoxin-induced uveitis (EIU) was established in rats by intravitreal injection of lipopolysaccharide (LPS). GILZ levels decreased in the EIU retina after LPS injection. Retinal GILZ was downregulated by recombinant lentivirus-delivered short-hairpin RNA targeting GILZ (shRNA-GILZ-rLV) and upregulated by recombinant lentivirus-mediated GILZ overexpression (Oe-GILZ-rLV). GILZ silencing attenuated the anti-inflammatory effects of intravitreal injection of triamcinolone acetonide (TA) in the EIU retina, as demonstrated by increased retinal interleukin (IL)-1β, monocyte chemoattractant protein (MCP)-1and intercellular cell adhesion molecule-1 expression at 18 h after TA injection. A Bio-Plex cytokine assay and western blotting demonstrated that GILZ overexpression inhibited the effects of LPS, downregulating retinal IL-1β, MCP-1, MIP-1α, and IL-17 and inhibiting LPS-induced activation of the retinal toll-like receptor 4-myeloid differentiation factor 88 signaling pathway. At 48 and 72 h after LPS injection, the clinical score of inflammation was significantly lower in Oe-GILZ-rLV-transfected eyes than in blank-rLV-transfected eyes. Histological examination showed a 67.85% reduction of infiltrating inflammatory cells in the anterior chamber and a 58.97% reduction in vitreous cavity of Oe-GILZ-rLV transfected eyes at 48 h after LPS injection. Taken together, our results suggest that GILZ is a novel therapeutic target for the treatment of retinal inflammatory diseases.

S100A8 promotes migration and infiltration of inflammatory cells in acute anterior uveitis

Uveitis, the pathologic condition of inflammation of the uvea, frequently leads to severe vision loss and blindness. S100A8 is a calcium-binding protein which mainly expresses in granulocytes and monocytes and plays a prominent role in the regulation of inflammatory processes and immune response. Here, we determined the role of S100A8-positive cells in acute anterior uveitis (AAU) and keratitis. In rat models of endotoxin (lipopolisaccharide, LPS) -induced uveitis (EIU) and keratitis, S100A8-positive granulocytes and monocytes increased significantly in the iris-ciliary body and cornea as well as in the blood. Interestingly, Glucocorticoids slightly increased S100A8 levels in leukocytes, but reduced its presence significantly in the iris-ciliary body after LPS injection. Moreover, inhibition of NF-kB activation remarkably suppressed both progression of AAU and total S100A8 levels in leukocytes and the iris-ciliary body after LPS administration. Additionally, S100A8 protein level was also found to be elevated in the serum of AAU patients parallel with the progression of AAU through the designated clinical stages. Thus, S100A8 plays a pivotal role in the processes of AAU through involvement in migration and infiltration of S100A8-positive cells. Our findings suggest that serum levels of S100A8 protein can be used to monitor inflammatory activity in AAU.

Endoplasmic reticulum stress-regulated CXCR3 pathway mediates inflammation and neuronal injury in acute glaucoma

Acute glaucoma is a leading cause of irreversible blindness in East Asia. The mechanisms underlying retinal neuronal injury induced by a sudden rise in intraocular pressure (IOP) remain obscure. Here we demonstrate that the activation of CXCL10/CXCR3 axis, which mediates the recruitment and activation of inflammatory cells, has a critical role in a mouse model of acute glaucoma. The mRNA and protein expression levels of CXCL10 and CXCR3 were significantly increased after IOP-induced retinal ischemia. Blockade of the CXCR3 pathway by deleting CXCR3 gene significantly attenuated ischemic injury-induced upregulation of inflammatory molecules (interleukin-1β and E-selectin), inhibited the recruitment of microglia/monocyte to the superficial retina, reduced peroxynitrite formation, and prevented the loss of neurons within the ganglion cell layer. In contrast, intravitreal delivery of CXCL10 increased leukocyte recruitment and retinal cell apoptosis. Inhibition of endoplasmic reticulum (ER) stress with chemical chaperones partially blocked ischemic injury-induced CXCL10 upregulation, whereas induction of ER stress with tunicamycin enhanced CXCL10 expression in retina and primary retinal ganglion cells. Interestingly, deleting CXCR3 attenuated ER stress-induced retinal cell death. In conclusion, these results indicate that ER stress-medicated activation of CXCL10/CXCR3 pathway has an important role in retinal inflammation and neuronal injury after high IOP-induced ischemia.

Total IgE and eotaxin (CCL11) contents in tears of patients suffering from seasonal allergic conjunctivitis

Background

To prospectively investigate patients with seasonal allergic conjunctivitis (SAC) during the pollen season and test associations between tears total IgE, eotaxin concentrations, and SAC severity.

Methods

Enrolled patients presented ocular symptoms and clinical signs of SAC at the time of presentation. Ocular itching, hyperaemia, chemosis, eyelid swelling, and tearing were scored, and the sum of these scores was defined as the clinical score. Conjunctival papillae were separately graded. We measured eotaxin concentration in tears by an enzyme-linked immunosorbent assay (ELISA) and total tear IgE by Lacrytest strip.

Results

Among thirty patients (30 eyes), 11 showed neither tear IgE nor tear eotaxin, while 15 out of 19 patients with positive IgE values presented a positive amount of eotaxin in their tears (Fisher’s test: p < 0.001). The mean eotaxin concentration was 641 ± 154 (SEM) pg/ml. In patients with no amount of tear IgE, we observed a lower conjunctival papilla grade than in patients whose tears contained some amount of IgE (trend test: p = 0.032). In the 15 patients whose tear eotaxin concentration was null, tear IgE concentration was 5.3 ± 3.5 arbitrary units; in the other 15 patients whose eotaxin was positive, IgE reached 21 ± 4.3 arbitrary U (Mann–Whitney: p < 0.001). We measured 127 ± 47 pg/ml eotaxin in patients with no history of SAC but newly diagnosed as suffering from SAC, and 852 ± 218 pg/ml eotaxin in patients with a known SAC (p = 0.008). In contrast, tear IgE concentrations of both groups did not differ statistically significantly (p = 0.947).

Conclusions

If IgE and eotaxin secreted in tears are major contributors in SAC pathogenesis, they however act at different steps of the process.

Vascular endothelial growth factor in a recipient cornea acts as a prognostic factor for corneal graft reaction development

PURPOSE

To evaluate whether the vascular endothelial growth factor A (VEGF-A) in the recipient cornea measured at the time of penetrating keratoplasty (PK) can act as a prognostic factor for corneal graft reaction development.

METHODS

The study included 25 eyes (of 25 patients) scheduled for PK. According to preoperative clinical finding, patients were divided into three groups: inflammatory with neovascularization (n = 11); inflammatory without neovascularization (n = 7); and non-inflammatory (n = 7). One half of the recipient cornea was analyzed for the levels of VEGF-A protein using a commercial enzyme-linked immunosorbent assay; the other half was analyzed to determine the loci of VEGF-A production by immunohistochemistry. The frequencies of corneal graft reaction and rejection were recorded, together with the improvement of visual acuity. Twenty-five donor corneas obtained from cadaver eyes represented the control group (n = 25).

RESULTS

There was a statistically significant difference in the levels of VEGF-A protein between the recipient corneal buttons obtained from eyes with inflammatory changes and neovascularization, and those from the non-inflammatory group and controls (p < 0.01). The level of VEGF-A was 287.74 pg/ml (standard deviation [SD] = 129.181) in the inflammatory with corneal neovascularization group, 227.64 pg/ml (SD = 85.590) in the inflammatory without neovascularization group, 115.37 pg/ml (SD = 105.93) in the non-inflammatory group, and 142.28 pg/ml (SD = 93.081) in the control group. Graft reaction/rejection rate was 54.5%/45.5% in the inflammatory with neovascularization group, 14.3%/0% in the inflammatory without neovascularization group, and 14.3%/14.3% in non-inflammatory group. Patients who developed clinical signs of graft reaction during the postoperative follow-up had a significantly higher level of VEGF-A (307.4 pg/ml, SD = 100.058) compared with those without any signs of graft reaction (182.8 pg/ml, SD = 124.987).

CONCLUSION

Our results suggest that both graft reaction and final graft rejection occur more often in patients with increased levels of VEGF-A in a recipient cornea at the time of PK.

CC chemokine receptor 5: the interface of host immunity and cancer

Solid tumors are embedded in a stromal microenvironment consisting of immune cells, such as macrophages and lymphocytes, as well as nonimmune cells, such as endothelial cells and fibroblasts. Chemokines are a type of small secreted chemotactic cytokine and together with their receptors play key roles in the immune defense. Critically, they regulate cancer cellular migration and also contribute to their proliferation and survival. The CCR5 chemokine receptor is involved in leucocytes chemotaxis to sites of inflammation and plays an important role in the macrophages, T cells, and monocytes recruitment. Additionally, CCR5 may have an indirect effect on cancer progression by controlling the antitumor immune response, since it has been demonstrated that its expression could promote tumor growth and contribute to tumor metastasis, in different types of malignant tumors. Furthermore, it was demonstrated that a CCR5 antagonist may inhibit tumor growth, consisting of a possible therapeutic target. In this context, the present review focuses on the establishment of CCR5 within the interface of host immunity, tumor microenvironment, and its potential as a targeting to immunotherapy.

Age-Related Macular Degeneration: Pathogenesis, Genetic Background, and the Role of Nutritional Supplements

Age-related macular degeneration (ARMD) is the leading cause of severe vision loss and blindness worldwide, mainly affecting people over 65 years old. Dry and wet ARDM are the main types of the disease, which seem to have a multifactorial background. The aim of this review is to summarize the mechanisms of ARMD pathogenesis and exhibit the role of diet and nutritional supplements in the onset and progression of the disease. Environmental factors, such as smoking, alcohol, and, diet appear to interact with mutations in nuclear and mitochondrial DNA, contributing to the pathogenesis of ARMD. Inflammatory mediators and oxidative stress, induced by the daily exposure of retina to high pressure of oxygen and light radiation, have been also associated with ARMD lesions. Other than medical and surgical therapies, nutritional supplements hold a significant role in the prevention and treatment of ARMD, eliminating the progression of macular degeneration.

Chemokine CXCL-1 expression in the subretinal fluid during rhegmatogenous retinal detachment

PURPOSE

To investigate the expression of chemokine CXCL-1 in the subretinal fluid (SRF) during rhegmatogenous retinal detachment (RRD) and identify potential correlations with number of quadrants involved and duration of the detachment.

METHODS AND RESULTS

Inclusion criteria were patients aged 18 years or older and primary RRD possibly complicated by proliferative vitreoretinopathy (PVR). CXCL-1 levels were measured in 36 SRF samples from 36 RRD patients. Mean CXCL-1 levels (102 ± 37 pg/mL) were significantly higher (p = 0.050) compared to controls. CXCL-1 levels correlated significantly with age (p = 0.001) and RRD duration (p = 0.002). Maximum CXCL-1 levels coincided with total RRD, 29- to 60-day duration and PVR grade C.

CONCLUSIONS

The findings of this study may contribute to increased understanding regarding the role of CXCL-1 during the onset and progression of the wound healing process in the context of RRD and PVR.

The role of macrophage class a scavenger receptors in a laser-induced murine choroidal neovascularization model

PURPOSE

Laser-induced choroidal neovascularization (CNV) is a widely used model to mimic many features of CNV resulting from wet AMD. Macrophages have been implicated in the pathogenesis of AMD. Class A scavenger receptors, scavenger receptor-A (SR-A) and macrophage receptor with collagenous domain (MARCO), are expressed on macrophages and are associated with macrophage function. The goal of this study is to examine the role of macrophage scavenger receptors in immune cell recruitment and the formation of CNV.

METHODS

Laser photocoagulation was performed in wild-type and knockout mice with deletion of SR-A (SR-A(-/-)), MARCO (MARCO(-/-)), or both SR-A and MARCO double knockout (DKO). Immune cell recruitment at different time points and CNV lesions at 14 days after laser treatment were evaluated through immunostaining and confocal microscopy. Microarray analysis was performed in eyes 1 day after laser injury.

RESULTS

Wild-type eyes showed higher chemokine/receptor expression compared with knockout eyes after laser injury. Scavenger receptor deficiency markedly impaired the recruitment of neutrophils and macrophages to CNV lesions at 1- and 3-days post laser injury, respectively. Significantly reduced CNV volumes were found in the eyes from scavenger receptor knockout mice compared with wild-type mice.

CONCLUSIONS

The deficiency of scavenger receptors impairs the formation of CNV and immune cell recruitment. Our findings suggest a potential role for scavenger receptors in contributing to CNV formation and inflammation in AMD.

Pathophysiology of proliferative vitreoretinopathy in retinal detachment

Because proliferative vitreoretinopathy cannot be effectively treated, its prevention is indispensable for the success of surgery for retinal detachment. The elaboration of preventive and therapeutic strategies depends upon the identification of patients who are genetically predisposed to develop the disease, as well as upon an understanding of the biological process involved and the role of local factors, such as the status of the uveovascular barrier. Detachment of the retina or vitreous activates glia to release cytokines and ATP, which not only protect the neuroretina but also promote inflammation, retinal ischemia, cell proliferation, and tissue remodeling. The vitreal microenvironment favors cellular de-differentiation and proliferation of cells with nonspecific nutritional requirements. This may render a pharmacological inhibition of their growth difficult without causing damage to the pharmacologically vulnerable neuroretina. Moreover, reattachment of the retina relies upon the local induction of a controlled wound-healing response involving macrophages and proliferating glia. Hence, the functional outcome of proliferative vitreoretinopathy will be determined by the equilibrium established between protective and destructive repair mechanisms, which will be influenced by the location and the degree of damage to the photoreceptor cells that is induced by peri-retinal gliosis.

Curcumin enhances neuronal survival in N-methyl-d-aspartic acid toxicity by inducing RANTES expression in astrocytes via PI-3K and MAPK signaling pathways

OBJECT

Neuroinflammation, which is characterized by the overproduction of cytokines and chemokines, plays an important role in neurodegenerative diseases, especially in Alzheimer's disease (AD). In the brain, chemokines are predominantly released by astrocytes and microglias. Expression of RANTES, as well as other cytokines, is involved in the inflammatory cascade that contributes to neurodegeneration in AD. Expression of RANTES may also have a neuroprotective effect. We sought to investigate whether curcumin exhibited neuroprotective and antioxidant activity via enhanced RANTES expression by astrocytes in cortical neuron cultures. We evaluated the neuroprotective and anti-neurodegenerative effects of curcumin in NMDA toxicity and in long-term cultures.

METHODS

Pregnant female Sprague-Dawley (SD) rats were used for primary culture of cortical neurons, and neonatal 0- to 2-day-old SD rats were used for primary culture of astrocytes. Cultured astrocytes were conditioned with curcumin to prepare astrocyte-conditioned medium (ACM). Real-time polymerase chain reaction was performed to assess RANTES and iNOS mRNA expression in astrocytes following curcumin treatment. ELISA was used to detect astrocyte-secreted RANTES protein in ACM with curcumin treatment. JAK/STAT, PI-3K, PKC and MAPK inhibitors were used to ascertain whether the effects of curcumin involved these signaling pathways. To evaluate the effects of curcumin-enhanced astrocytes on neuronal survival, cultured cortical neurons treated or untreated with NMDA were incubated in ACM with or without curcumin treatment. Long-term culture (15days in vitro, DIV) was performed to investigate the effects of curcumin-treated astrocytes on the survival of cultured cortical neurons. Neuronal survival rate was assessed by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction activity assay (for cell viability), and the lactate dehydrogenase (LDH) release assay (for cell death).

RESULTS

We demonstrated that curcumin enhanced RANTES expression in primary cultured astrocytes, and that this effect was related to activation of PI-3K and MAPK signaling pathways. We found that curcumin inhibited iNOS expression in primary cultured astrocytes in non-stressed condition. We also found that neurons exposed to NMDA and cultured with curcumin treated ACM, which characteristically exhibited elevated RANTES expression showed higher level of cell viability and lower level of cell death. Using a small interfering RNA (siRNA) knockdown model, we found evidence that the basal level of RANTES expression in non-stimulated astrocytes provided neuroprotection.

CONCLUSION

We postulate that the enhanced neuronal survival by curcumin treatment in NMDA toxicity and long-term cultures was in part attributable to elevated astrocyte-derived RANTES expression via activation of PI3K/MAPK signaling pathways.

The role of CCR1 expression in the retinal degeneration in rd mice

PURPOSE

Chemokine receptors are reported to be involved in neuronal cell death and CNS neurodegenerative diseases. The aim of the current study was to investigate the expression of CCR1, a major chemokine receptor for CC chemokines in retinal dystrophy in rd (retinal degeneration) mice and further explore its role in photoreceptor degeneration.

MATERIALS AND METHODS

The expression levels of CCR1 mRNA in the whole control and rd retinas at postnatal days (P) 8, 10, 12, 14, 16, and 18 were determined by RT-PCR assay. Location of CCR1 in the retina of rd mice at each age group was studied by immunohistochemical analysis. Expression of CCR1 in the photoreceptor cells and apoptotic cells was determined by double labeling.

RESULTS

Expression of CCR1 mRNA was noted in both control and rd retinas at each age group. CCR1-positive cells started to emerge in the outer nuclear layer (ONL) in rd retinas at P8 and reached a peak at P12 and P14. Double labeling of CCR1 with rhodopsin, CD11b, or TUNEL staining showed expression of CCR1 in the photoreceptor cells, rather than in the microglial cells. Partial CCR1 expression was observed in some of the apoptotic photoreceptor cells.

CONCLUSIONS

Expression of CCR1 in the photoreceptor cells was increased with the progress of retinal degeneration in rd mice. Activation of CCR1 may play a role in the photoreceptor apoptosis.

Proinflammatory cytokines are involved in the initiation of the abnormal matrix process in pseudoexfoliation syndrome/glaucoma

Pseudoexfoliation (PEX) syndrome, which is an age-related, generalized elastotic matrix process, currently represents the most common identifiable risk factor for open-angle glaucoma. Dysregulated expression of proinflammatory cytokines has been implicated in the initiation of various fibrotic disorders and in the pathophysiology of glaucoma. Here we investigated the presence, expression, regulation, and functional significance of proinflammatory cytokines in eyes with early and late stages of PEX syndrome/glaucoma in comparison with normal and glaucomatous control eyes using multiplex bead analysis, immunoassays, real-time PCR, Western blotting, immunohistochemistry, and cell culture models. Early stages of PEX syndrome were characterized by approximately threefold (P < 0.005) elevated interleukin (IL)-6 and IL-8 levels in the aqueous humor and a concomitant approximately twofold (P < 0.001) increase in mRNA expression levels in anterior segment tissues as compared with controls. In contrast, late stages of PEX syndrome/glaucoma did not differ significantly from controls. IL-6, IL-6 receptor, and phospho-signal transducer and activator of transcription 3 could be mainly localized to walls of iris vessels and to the nonpigmented epithelium of ciliary processes. IL-6 and IL-8 were significantly up-regulated by ciliary epithelial cells in response to hypoxia or oxidative stress in vitro, whereas IL-6, but not IL-8, induced the expression of transforming growth factor-beta1 and elastic fiber proteins. These findings support a role for a stress-induced, spatially, and temporally restricted subclinical inflammation in the onset of the fibrotic matrix process characteristic of PEX syndrome/glaucoma.

Novel aspects of corneal angiogenic and lymphangiogenic privilege

In this article, we provide the results of experimental studies demonstrating that corneal avascularity is an active process involving the production of anti-angiogenic factors, which counterbalance the pro-angiogenic/lymphangiogenic factors that are upregulated during wound healing. We also summarize pertinent published reports regarding corneal neovascularization (NV), corneal lymphangiogenesis and corneal angiogenic/lymphangiogenic privilege. We outline the clinical causes of corneal NV, and discuss the angiogenic proteins (VEGF and bFGF) and angiogenesis regulatory proteins. We also describe the role of matrix metalloproteinases MMP-2, -7, and MT1-MMP, anti-angiogenic factors, and lymphangiogenic regulatory proteins during corneal wound healing. Established and potential new therapies for the treatment of corneal neovascularization are also discussed.

Expression of CXCL9, -10, -11, and CXCR3 in the tear film and ocular surface of patients with dry eye syndrome

PURPOSE

To investigate the expression of CXCL9, -10, -11, and CXCR3 in the tear film and ocular surface of patients with dry eye syndrome.

METHODS

Thirty-three patients with dry eye (16 with and 17 without Sjögren's syndrome) and 15 control subjects were recruited. The concentrations of CXCL9, -10, and -11 in tears were measured with enzyme-linked immunosorbent assays. The correlation between chemokine levels and tear film and ocular surface parameters was analyzed. The expression of CXCL9, -10, -11, and CXCR3 in the conjunctiva was evaluated by using immunohistochemistry. Flow cytometry was performed to count CXCR3(+) cells and CXCR3(+)CD4(+) cells in the conjunctiva.

RESULTS

The concentrations of CXCL9, -10, and -11 were 1,148 +/- 1,088, 24,338 +/- 8,706, and 853 +/- 334 pg/mL, in the patients with dry eye, and 272 +/- 269 (P = 0.01), 18,149 +/- 5,266 (P = 0.02), and 486 +/- 175 (P < 0.01) pg/mL in the control subjects, respectively. The concentrations significantly increased in tears of the patients with Sjögren's syndrome compared with those of the patients with non-Sjögren's dry eye (P < 0.05). CXCL10 levels correlated significantly with basal tear secretion, and CXCL11 levels correlated significantly with basal tear secretion, tear clearance rate, keratoepitheliopathy score, and goblet cell density (P < 0.05). Staining for CXCL9, -10, -11, and CXCR3 increased in patients with dry eye, especially in the patients with Sjögren's syndrome. Flow cytometry demonstrated an increased number of CXCR3(+) and CXCR3(+)CD4(+) cells in all the patients with dry eye.

CONCLUSIONS

Expression of CXCL9, -10, -11, and CXCR3 increased in the tear film and ocular surface of patients with dry eye syndrome, especially in those with Sjögren's syndrome. CXCL11 levels correlated significantly with various tear film and ocular surface parameters. (ClinicalTrials.gov number, NCT00991679.).

IFN-beta provides immuno-protection in the retina by inhibiting ICAM-1 and CXCL9 in retinal pigment epithelial cells

The retinal pigment epithelial (RPE) cell is a potent regulatory cell that facilitates normal physiologic processes and plays a critical role in a variety of retinal diseases. We evaluated IFN-beta production in human RPE cells through TLR signaling and investigated the effects of IFN-beta on RPE cells. RPE cells treated with poly(I:C) or infected with an RNA virus produce IFN-beta. Kinetic studies revealed that IFN-beta levels continue to increase over a 48-h period and this was associated with the up-regulation of IRF-7 gene expression, a known positive feedback molecule for IFN-beta production. Microarray analysis revealed that in IFN-beta treated cells, 480 genes of 22,283 genes were up or down-regulated by >2-fold. We hypothesize that IFN-beta induction during TLR signaling in the retina is an immunosuppressive factor produced to limit immunopathologic damage. Cytokine activation of RPE cells results in the production of the chemokines, CXCL9 and CXCL10, and the adhesion molecule, ICAM-1. Pretreatment of RPE cells with IFN-beta resulted in inhibition of ICAM-1 production and elimination of CXCL9 production. This treatment did not alter CXCL10 production. Anti-IFN-beta Ab blocked the inhibitory action of IFN-beta. Real time PCR analysis revealed that IFN-beta treatment inhibited gene expression of sICAM-1 and CXCL9. The results indicate a critical role for RPE cell derived IFN-beta in the down-regulation of CXCL9 and ICAM-1 expression in the retina and suggest that the inhibition of CXCL9 is an immuno-suppressive mechanism that protects the retina from excessive inflammation.

Experimental coronavirus retinopathy (ECOR): retinal degeneration susceptible mice have an augmented interferon and chemokine (CXCL9, CXCL10) response early after virus infection

Mouse hepatitis virus induces a biphasic disease in BALB/c mice that consists of an acute retinitis followed by progression to a chronic retinal degeneration with autoimmune reactivity. Retinal degeneration resistant CD-1 mice do not develop the late phase. What host factors contribute to the distinct responses to the virus are unknown. Herein, we show that IFN-α, IFN-β and IFN-γ act in concert as part of the innate immune response to the retinal infection. At day 2, high serum levels of IFN-γ, CXCL9 and CXCL10, were detected in BALB/c mice. Moreover, elevated levels of CXCL9 and CXCL10 gene expression were detected in retinal tissue. Although IFN-γ and the chemokines were detected in CD-1 mice, they were at significantly lower levels compared to BALB/c mice. These augmented innate responses observed correlated with the development of autoimmune reactivity and retinal degeneration and thus may contribute to the pathogenic processes.

Altered chemokine profile associated with exacerbated autoimmune pathology under conditions of genetic interferon-gamma deficiency

PURPOSE

A prior study showed that mice deficient in IFN-gamma (GKO) are more susceptible to experimental autoimmune uveitis (EAU) than are wild-type (WT) mice. Histopathology of uveitic eyes revealed that the ocular infiltrate in GKO mice was dominated by neutrophils and eosinophils rather than by mononuclear cells, as in WT mice. The present study was conducted to explore the differential expression of chemokine(s) likely to account for the distinct inflammatory cell composition in uveitic eyes of WT and GKO mice.

METHODS

Mice were immunized to induce EAU. Lymph nodes draining the site of the immunization and the eyes were collected at different time points for chemokine analysis. Microarray, real-time PCR and protein analyses were performed to examine the expression of chemokines in WT and GKO mice.

RESULTS

Many chemokines were differentially upregulated in GKO versus WT mice. Expression of the Th1-associated chemokines CXCL10, CXCL9, CCL5, and CXCL11 was elevated in WT mice, whereas the Th2-associated chemokines CCL11, CCL17, and CCL1 and the Th17-associated chemokines CCL22 and CXCL2 were elevated in the GKO mice. Depletion of granulocytes abrogated EAU in both WT and GKO mice.

CONCLUSIONS

These results suggest that Th1-associated chemokines play a critical role in the attraction of mononuclear cells to the eyes in the presence of IFN-gamma, while in the absence of this cytokine, Th2- and Th17-related chemokines may be the key elements for influx of granulocytes.

Increased serum levels of CXCL8 chemokine in acute toxoplasmic retinochoroiditis

PURPOSE

Chemokines have been implicated in the control of leucocyte infiltration in uveitis and in modulating angiogenesis in several ocular conditions. Toxoplasmic retinochoroiditis is a common cause of posterior uveitis. This study aimed to evaluate the serum concentrations of CC and CXC chemokines in patients with acute toxoplasmic retinochoroiditis.

METHODS

The levels of five chemokines (CCL2, CCL11, CXCL9, CXCL8 and CXCL10) were evaluated in the serum of patients with active toxoplasmic retinochoroiditis (n = 55) and control subjects (n = 40). In a subset of patients (n = 18), a second measure of serum levels of chemokines was performed after the completion of oral treatment with pyrimethamine (25 mg/day), sulphadiazine (1 g, four times per day), folinic acid (7.5 mg/day) and prednisone (initial dose: 1 mg/kg/day) for approximately 30 days.

RESULTS

Patients with toxoplasmic retinochoroiditis, notably those presenting with vasculitis, had increased serum levels of CXCL8 (mean +/- standard error of the mean [SEM] 35.1 +/- 6.5 pg/ml) compared with control subjects (mean +/- SEM 16.0 +/- 2.3 pg/ml; p = 0.01). There were no differences between patients and controls in serum levels of the other chemokines measured. The size of ocular lesions correlated significantly with serum levels of CXCL8 and CXCL9. After treatment, there was a significant reduction in serum levels of CXCL8. Severity of vitreous opacities did not correlate with serum levels of these chemokines.

CONCLUSIONS

These data suggest a role for CXCL8 in the inflammatory process of acute toxoplasmic retinochoroiditis. Furthermore, CXCL8 may be a useful marker for patient follow-up.

Inflammatory mediators of uveitis: cytokines and chemokines

PURPOSE OF REVIEW

The study of uveitis has been restricted by the difficulty in obtaining sufficient intraocular material from both human disease and experimental models. Recent developments in cytokine and chemokine detection have overcome many of these problems. This review presents a summary of the technologic advances in this area.

RECENT FINDINGS

Recent advances in cytokine analysis, in particular multiplexed bead immunoassays, have allowed the measurement of an extensive array of cytokines and chemokines from very small sample volumes. This has revolutionized uveitis research, enabling measurement of a large profile of cytokines and chemokines in intraocular fluid, such as aqueous humour. This allows us to recognize complex patterns of cytokines and chemokines from different forms of uveitis and to examine relationships between different molecules.

SUMMARY

The spectrum of proinflammatory cytokines and chemokines known to be implicated in uveitis has increased over recent years. Many of these molecules have also been found in experimental models of disease and may represent attractive therapeutic targets for the future. With recent advances in cytokine detection, an extension of these techniques with a more detailed analysis of different uveitis conditions may provide useful diagnostic and prognostic information for this potentially blinding group of diseases.

Simultaneous quantification of 17 immune mediators in aqueous humour from patients with corneal rejection

PURPOSE

To simultaneously quantitate and compare the concentrations of 17 immune mediators: (1) the cytokines interleukin-1beta, IL-2, IL-4, IL-5, IL-6, IL-7, IL-10, IL-12p70, IL-13, IL-17, tumour necrosis factor-alpha, interferon-gamma; (2) the growth factors granulocyte-monocyte colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF), and (3) the chemokines CXCL-8, monocyte chemoattractant protein-1, and macrophage inflammatory protein-1beta in aqueous humour from patients with corneal rejection and patients with a non-inflammatory condition in the anterior chamber.

METHODS

Aqueous humour was obtained by paracentesis of the anterior chamber in 14 patients with corneal rejection, three patients with cataract and six patients with Fuchs' endothelial dystrophy. Simultaneous quantitation of 17 mediators in 25 micro l aqueous humour from each patient was performed by employing a highly sensitive Luminex 100 multiplex array assay.

RESULTS

All 17 immune mediators were detected in aqueous humour from rejection patients. The ranges of the immune mediators were determined. The immune mediators were significantly increased in aqueous humour from rejection patients compared with that from other patients.

CONCLUSIONS

The Luminex 100 multiplex array assay is very efficient in simultaneous quantitation of multiple immune mediators in small volumes of aqueous humour. A total of 17 immune mediators were increased in aqueous humour from rejection patients. This underlines the complex immunological interactions of the rejection process.

Descemet membrane endothelial keratoplasty (DMEK)

PURPOSE

To describe Descemet membrane endothelial keratoplasty (DMEK) with organ cultured Descemet membrane (DM) in a human cadaver eye model and a patient with Fuchs endothelial dystrophy.

METHODS

In 10 human cadaver eyes and 1 patient eye, a 3.5-mm clear corneal tunnel incision was made. The anterior chamber was filled with air, and the DM was stripped off from the posterior stroma. From organ-cultured donor corneo-scleral rims, 9.0-mm-diameter "DM rolls" were harvested. Each donor DM roll was inserted into a recipient anterior chamber, positioned onto the posterior stroma, and kept in position by completely filling the anterior chamber with air for 30 minutes.

RESULTS

In all recipient eyes, the donor DM maintained its position after a 30-minute air-fill of the anterior chamber followed by an air-liquid exchange. In the patient's eye, 1 week after transplantation, best-corrected visual acuity was 1.0 (20/20) with the patient's preoperative refraction, and the endothelial cell density averaged 2350 cells/mm.

CONCLUSION

DMEK may provide quick visual rehabilitation in the treatment of corneal endothelial disorders by transplantation of an organ-cultured DM transplanted through a clear corneal tunnel incision. DMEK may be a highly accessible procedure to corneal surgeons, because donor DM sheets can be prepared from preserved corneo-scleral rims.

Viral infection of the lungs through the eye

Respiratory syncytial virus (RSV) is the foremost respiratory pathogen in newborns and claims millions of lives annually. However, there has been no methodical study of the pathway(s) of entry of RSV or its interaction with nonrespiratory tissues. We and others have recently established a significant association between allergic conjunctivitis and the presence of RSV in the eye. Here we adopt a BALB/c mouse model and demonstrate that when instilled in the live murine eye, RSV not only replicated robustly in the eye but also migrated to the lung and produced a respiratory disease that is indistinguishable from the standard, nasally acquired RSV disease. Ocularly applied synthetic anti-RSV small interfering RNA prevented infection of the eye as well as the lung. RSV infection of the eye activated a plethora of ocular cytokines and chemokines with profound relevance to inflammation of the eye. Anticytokine treatments in the eye reduced ocular inflammation but had no effect on viral growth in both eye and lung, demonstrating a role of the cytokine response in ocular pathology. These results establish the eye as a major gateway of respiratory infection and a respiratory virus as a bona fide eye pathogen, thus offering novel intervention and treatment options.

RANTES stimulates Ca2+ mobilization and inositol trisphosphate (IP3) formation in cells transfected with G protein-coupled receptor 75

BACKGROUND AND PURPOSE

RANTES is an inflammatory chemokine with a critical role in T-lymphocyte activation and proliferation. Its effects are mediated through G protein-coupled heptahelical receptors (GPCRs). We show for the first time that RANTES activates the orphan G protein-coupled receptor 75 (GPR75).

EXPERIMENTAL APPROACH

To identify a ligand for GPR75 we have used three different and independent methods, namely luciferase assay, bioluminescence assay and IP3 accumulation assay.

KEY RESULTS

Treatment of cells expressing GPR75 with subnanomolar concentrations of RANTES led to stimulation of the luciferase activity in a reporter-gene assay, an increase in inositol trisphosphate, and intracellular Ca2+. The latter effect was blocked by the phospholipase-C inhibitor (PLC) U73122 indicating that Gq proteins mediate GPR75 signaling. RANTES enhanced the phosphorylation of AKT and mitogen-activated protein kinase (MAPK) in GPR75-transfected cells and this effect was blocked by the PLC inhibitor U73122 and the phosphatidylinositol 3-kinase (PI3K) inhibitor, wortmannin. The hippocampal cell line HT22, which expresses GPR75 endogenously, but not the other known RANTES receptors, was used to study the effects of RANTES and GPR75 on neuronal survival. Treatment of HT22 cells with RANTES significantly reduced the neurotoxicity of amyloid-beta peptides, by activating PLC and PI3K.

CONCLUSIONS AND IMPLICATIONS

This demonstrate clearly and undoubtedly the ability of RANTES to act on GPR75. Defects in the RANTES/GPR75-signaling pathway may contribute to neuroinflammatory and neurodegenerative processes as observed in Alzheimer's disease.

Distinct cytokine and chemokine profiles in the aqueous of patients with uveitis and cystoid macular edema

PURPOSE

To investigate the global cytokine and chemokine expression pattern in the aqueous humor of uveitis patients and relate them to clinical features.

DESIGN

Cross-sectional study.

METHODS

In 31 aqueous humor samples from uveitis patients, the concentration of mediators was measured by a multiplex immunoassay. Eleven control samples were included.

RESULTS

Uveitis samples had higher levels of interleukin-6, interleukin-8, soluble intercellular adhesion molecule, soluble vascular cell adhesion molecule (sVCAM), and interferon-inducible protein-10 (IP-10) than nonuveitis controls. Active uveitis samples had higher levels of interleukin-6, interleukin-10, interferon-gamma, sVCAM, regulated on activation, normal T cell expressed and secreted (RANTES), and IP-10 than quiescent uveitis samples. Infectious uveitis was associated with higher levels of interleukin-10 than noninfectious uveitis (P < .03 for all subgroups). No significant differences were found between cystoid macular edema (CME) and non-CME samples.

CONCLUSIONS

Elevated levels of specific mediators were found in active and in infectious uveitis, but not in CME. Mediator profiles might lead to a better understanding of the pathogenesis of uveitis.

The complement system plays a critical role in the development of experimental autoimmune anterior uveitis

PURPOSE

The role of complement in ocular autoimmunity was explored in a experimental autoimmune anterior uveitis (EAAU) animal model.

METHODS

EAAU was induced in Lewis rats by immunization with bovine melanin-associated antigen. Complement activation in the eye was monitored by Western blot for iC3b. The importance of complement to the development of EAAU was studied by comparing the course of intraocular inflammation in normal Lewis rats (complement-sufficient) with cobra venom factor-treated rats (complement-depleted). Eyes were harvested from both complement-sufficient and complement-depleted rats for mRNA and protein analysis for IFN-gamma, IL-10, and interferon-inducible protein (IP)-10. Intracellular adhesion molecule (ICAM)-1 and leukocyte-endothelial cell adhesion molecule (LECAM)-1 were detected by immunofluorescent staining. OX-42 was used to investigate the importance of iC3b and CR3 interaction in EAAU.

RESULTS

There was a correlation between ocular complement activation and disease progression in EAAU. The incidence, duration, and severity of disease were dramatically reduced after active immunization in complement-depleted rats. Complement depletion also completely suppressed adoptive transfer EAAU. The presence of complement was critical for local production of cytokines (IFN-gamma and IL-10), chemokines (IP-10), and adhesion molecules (ICAM-1 and LECAM-1) during EAAU. Furthermore, intraocular complement activation, specifically iC3b production and engagement of complement receptor 3 (CR3), had a significant impact on disease activity in EAAU.

CONCLUSIONS

The study provided the novel finding that complement activation plays a central role in the pathogenesis of ocular autoimmunity and may serve as a potential target for therapeutic intervention.

Capacity of ocular infiltrating T helper type 1 cells of patients with non-infectious uveitis to produce chemokines

BACKGROUND/AIMS

Chemokines are key molecules that initiate leucocyte infiltration to the inflammatory site. The involvement of chemokines in uveitis is well studied, yet the source of this molecule in the inflamed eye is not clearly identified. The possible sources of chemokines are ocular resident cells or the inflammatory cells infiltrated to the eye. Here the authors examined whether ocular infiltrating T cells of uveitis patients do produce chemokines.

METHODS

T cell clones (TCCs) were established from ocular infiltrating cells of patients with non-infectious uveitis. TCCs were characterised using flow cytometry. Spontaneous production of chemokines by TCCs was evaluated by ELISA.

RESULTS

TCCs from ocular infiltrating cells were revealed to be memory activated Th1 type CD4 positive cells. Those TCCs produced larger amounts of chemokines than TCCs from peripheral blood mononuclear cells of uveitis or healthy donors.

CONCLUSIONS

The present data indicate that ocular infiltrating T cells of patients with non-infectious uveitis produce chemokines and recruit further infiltrating lymphoid cells. Such T cells may have roles in the prolonged/chronic state of non-infectious uveitis.