Conjunctiva Resident γδ T Cells Expressed High Level of IL-17A and Promoted the Severity of Dry Eye

Incidence of Cytomegalovirus Infection After Repeat Keratoplasty and Associated Rate of Graft Failure

INTRODUCTION

The aim of this work was to compare the prognosis and characteristics of patients with Cytomegalovirus (CMV) infection (CMV+) with those of patients without virus infection (Virus-) undergoing repeat keratoplasty.

METHODS

This prospective propensity score-matched cohort study enrolled patients who underwent repeat keratoplasty for graft failure at the Peking University Third Hospital between January 2016 and May 2022. Patients with prior viral keratitis before the first keratoplasty were excluded. The primary outcome measure was the graft failure rate. The secondary outcome measures included the anterior segment characteristics, intraocular pressure (IOP), and endothelial cell density.

RESULTS

Ninety-four matched patient pairs were included. The graft failure rate in the CMV+ group (71%) was higher than that in the Virus- group (29%) (P < 0.001). CMV infection in the cornea increased the risk of repeat graft failure and shortened the median survival time (hazard ratio, 3.876; 95% confidence intervals, 2.554-5.884; P < 0.001). The characteristics of graft failure included exacerbation of ocular surface inflammation, neovascularization, and opacification. Epithelial defects, high IOP, and endothelial decompensation were observed at an increased frequency in the CMV+ group (all P < 0.005). Recurrent CMV infection presented as early endothelial infection in the CMV+ group. Recurrence of CMV infection was confined to the graft endothelium without involving the stroma and epithelium post-repeat endothelial keratoplasty.

CONCLUSIONS

CMV infection post-keratoplasty leads to persistent endothelial damage and graft opacification and significantly increases the risk of repeat graft failure. Localized recurrence of CMV infection in the endothelial grafts underscores the importance of monitoring and treatment.

TRIAL REGISTRATION

Chictr.org.cn, ChiCTR1800014684.

Varying conjunctival immune response adaptations of house finch populations to a rapidly evolving bacterial pathogen

Pathogen adaptations during host-pathogen co-evolution can cause the host balance between immunity and immunopathology to rapidly shift. However, little is known in natural disease systems about the immunological pathways optimised through the trade-off between immunity and self-damage. The evolutionary interaction between the conjunctival bacterial infection Mycoplasma gallisepticum (MG) and its avian host, the house finch (Haemorhous mexicanus), can provide insights into such adaptations in immune regulation. Here we use experimental infections to reveal immune variation in conjunctival tissue for house finches captured from four distinct populations differing in the length of their co-evolutionary histories with MG and their disease tolerance (defined as disease severity per pathogen load) in controlled infection studies. To differentiate contributions of host versus pathogen evolution, we compared house finch responses to one of two MG isolates: the original VA1994 isolate and a more evolutionarily derived one, VA2013. To identify differential gene expression involved in initiation of the immune response to MG, we performed 3'-end transcriptomic sequencing (QuantSeq) of samples from the infection site, conjunctiva, collected 3-days post-infection. In response to MG, we observed an increase in general pro-inflammatory signalling, as well as T-cell activation and IL17 pathway differentiation, associated with a decrease in the IL12/IL23 pathway signalling. The immune response was stronger in response to the evolutionarily derived MG isolate compared to the original one, consistent with known increases in MG virulence over time. The host populations differed namely in pre-activation immune gene expression, suggesting population-specific adaptations. Compared to other populations, finches from Virginia, which have the longest co-evolutionary history with MG, showed significantly higher expression of anti-inflammatory genes and Th1 mediators. This may explain the evolution of disease tolerance to MG infection in VA birds. We also show a potential modulating role of BCL10, a positive B- and T-cell regulator activating the NFKB signalling. Our results illuminate potential mechanisms of house finch adaptation to MG-induced immunopathology, contributing to understanding of the host evolutionary responses to pathogen-driven shifts in immunity-immunopathology trade-offs.

Transmembrane Protein CMTM6 Alleviates Ocular Inflammatory Response and Improves Corneal Epithelial Barrier Function in Experimental Dry Eye

Purpose

To investigate the impact of transmembrane protein CMTM6 on the pathogenesis of dry eye disease (DED) and elucidate its potential mechanisms.

Methods

CMTM6 expression was confirmed by database analysis, real-time polymerase chain reaction (RT-PCR), western blot, and immunohistochemistry. Tear secretion was measured using the phenol red thread test. Immune cell infiltration was assessed through flow cytometry. Barrier function was evaluated by fluorescein sodium staining, immunofluorescence staining of zonula occludens 1 (ZO-1), and electric cell-substrate impedance sensing (ECIS) assessment. For silencing CMTM6 expression, siRNA and shRNA were employed, along with lentiviral vector-mediated overexpression of CMTM6. Proinflammatory cytokine levels were analyzed by RT-PCR and cytometric bead array (CBA) analysis.

Results

CMTM6 showed high expression in healthy human and mouse corneal and conjunctival epithelium but was notably reduced in DED. Notably, this downregulation was correlated with disease severity. Cmtm6-/- dry eye (DE) mice displayed reduced tear secretion, severe corneal epithelial defects, decreased conjunctival goblet cell density, and upregulated inflammatory response. Additionally, Cmtm6-/- DE mice and CMTM6 knockdown human corneal epithelial cell-transformed (HCE-T) cells showed more severe barrier disruption and reduced expression of ZO-1. Knockdown of CMTM6 in HCE-T cells increased inflammatory responses induced by hyperosmotic stress, which was significantly mitigated by CMTM6 overexpression. Moreover, the level of phospho-p65 in hyperosmolarity-stimulated HCE-T cells increased after silencing CMTM6. Nuclear factor kappa B (NF-κB) p65 inhibition (JSH-23) reversed the excessive inflammatory responses caused by hyperosmolarity in CMTM6 knockdown HCE-T cells.

Conclusions

The reduction in CMTM6 expression on the ocular surface contributes to the pathogenesis of DED. The CMTM6-NF-κB p65 signaling pathway may serve as a promising therapeutic target for DED.

Mass cytometry reveals the corneal immune cell changes at single cell level in diabetic mice

Introduction

Diabetic ocular complications include sight-threatening consequences and decreased corneal sensitivity, characterized by decreased tear production, corneal sensitivity and delayed corneal epithelial wound healing. The pathogenesis of diabetic corneal disorders remains largely unknown. Growing evidence implies the participation of immune cells in the development of diabetic corneal diseases. Nonetheless, the immunological changes that result in diabetic corneal problems are largely unknown.

Methods

Mass cytometry by time of flight (CyTOF) was used to investigate immune cell cluster alterations associated with diabetic corneal disorders. CyTOF test was performed on corneal cells at a single level from 21-week-old diabetic (db/db) and non-diabetic (db/m) mice. A panel of 41 immune-related markers monitored different immune cell types in diabetic corneas. To investigate the proportion of each immune cell subpopulation, an unsupervised clustering method was employed, and T-distributed stochastic neighbor embedding was used to visualize the distinctions between different immune cell subsets.

Results

Through CyTOF test, we identified 10 immune cell subsets in the corneal tissues. In a novel way, we discovered significant immune alterations in diabetic corneas, including pronounced alterations in T cells and myeloid cell subgroups in diabetic corneas linked to potential biomarkers, including CD103, CCR2, SiglecF, Ly6G, and CD172a. Comprehensive immunological profiling indicated remarkable changes in the immune microenvironment in diabetic corneas, characterized by a notable decrease in CD103+CD8+ tissue-resident memory T (TRM) cells and Tregs, as well as a dramatic increase of γδT cells and subsets of CD11b+Ly6G+ myeloid-derived suppressor cells (MDSCs).

Conclusion

CyTOF analysis revealed significant alterations in the immune microenvironment during the development of diabetic corneal complications. This study mapped the immune microenvironment landscape of type 2 diabetic corneas, providing a fundamental understanding of immune-driven diabetic corneal disorders.

Clinical Characteristics and Tear Film Biomarkers in Patients With Chronic Dry Eye Disease After Femtosecond Laser-Assisted Laser in Situ Keratomileusis

PURPOSE

To investigate clinical characteristics and tear film biomarkers of patients with chronic dry eye disease (DED) following femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK).

METHODS

Patients were divided into the chronic DED after FS-LASIK (n = 36), DED without FS-LASIK (n = 39), and normal control (without FS-LASIK; n = 34) groups. Dry eye, pain, and psychological-related symptoms were evaluated using the Ocular Surface Disease Index (OSDI), Numerical Rating Scale (NRS), Neuropathic Pain Symptom Inventory Modified for the Eye (NPSI-Eye), and Hamilton Anxiety Rating Scale (HAMA) questionnaires. Ocular surface parameters, tear cytokines, and neuropeptide concentrations were evaluated with specific tests.

RESULTS

The DED after FS-LASIK group showed higher corneal fluorescein staining scores, but lower OSDI and NPSI-Eye scores than the DED without FS-LASIK group (all P < .05). Corneal sensitivity and nerve density decreased in the DED after FS-LASIK group (all P < .01). Granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-17A, IL-23, alpha-melanocyte stimulating hormone (α-MSH), oxytocin, and substance P levels were highest in the DED after FS-LASIK group, followed by the DED without FS-LASIK and normal control groups (all P < .05). Interferon-γ and neurotensin levels were only significantly higher in the DED after FS-LASIK group (all P < .05).

CONCLUSIONS

Patients with chronic DED after FS-LASIK showed milder ocular symptoms, greater epithelial damage, and higher levels of tear inflammatory cytokines and neuropeptides than patients with DED without FS-LASIK, indicating that the nervous and immune systems may play significant roles in FS-LASIK-related chronic DED development. [J Refract Surg. 2023;39(8):556-563.].

Salidroside alleviates oxidative stress in dry eye disease by activating autophagy through AMPK-Sirt1 pathway

Dry eye disease (DED) is a multifactorial disease, and oxidative stress plays a crucial role in its pathogenesis. Recently, multiple studies have shown that upregulation of autophagy can protect the cornea from oxidative stress damage. The present study investigated the therapeutic effects of salidroside, the main component of Rhodiola crenulata, in both in vivo and in vitro dry eye models. The results showed that topical eye drop treatment with salidroside restored corneal epithelium damage, increased tear secretion, and reduced cornea inflammation in the DED mice. Salidroside activated autophagy through AMP-activated protein kinase (AMPK)-sirtuin-1 (Sirt1) signaling pathway, which promoted the nuclear translocation of nuclear factor erythroid-2-related factor 2 (Nrf2) and increased the expression of downstream antioxidant factors heme oxygenase-1 (HO-1) and NAD(P)H quinone dehydrogenase 1 (NQO1). This process restored antioxidant enzyme activity, reduced reactive oxygen species (ROS) accumulation, and alleviated oxidative stress. The application of autophagy inhibitor chloroquine and AMPK inhibitor Compound C reversed the therapeutic efficacy of salidroside, validating the above findings. In conclusion, our data suggest that salidroside is a promising candidate for DED treatment.

Mapping Resident Immune Cells in the Murine Ocular Surface and Lacrimal Gland by Flow Cytometry

BACKGROUND

The ocular surface and lacrimal gland have a frontline position in mucosal immunology. However, there have been few updates to the immune cell atlas of these tissues in recent years.

PURPOSE

To map the immune cells in murine ocular surface tissues and lacrimal gland.

METHODS

Central and peripheral corneas, conjunctiva, and lacrimal gland were dissociated into single cell suspensions, followed by flow cytometry. Discrepancy of immune cells between the central and peripheral corneas was compared. In the conjunctiva and lacrimal gland, myeloid cells were clustered by tSNE and FlowSOM based on the expression of F4/80, Ly6C, Ly6G, and MHC II. ILCs, type 1 immune cells, and type 3 immune cells were analyzed.

RESULTS

The number of immune cells in peripheral corneas was about 16 folds of that in central corneas. B cells accounted for 8.74% of immune cells in murine peripheral corneas. In the conjunctiva and lacrimal gland, most myeloid cells tended out to be monocytes, macrophages, and classical dendritic cells (cDCs). ILC3 were 6.28% and 3.63% of ILCs in the conjunctiva and lacrimal gland, respectively. Th1, Tc1, and NK cells were predominant type 1 immune cells. γδ T17 cells and ILC3 outnumbered Th17 cells among type 3 T cells.

CONCLUSION

B cells resident in murine corneas were reported for the first time. Additionally, we proposed a strategy of clustering myeloid cells to better understand their heterogeneity in the conjunctiva and lacrimal gland based on tSNE and FlowSOM. Furthermore, we identified the ILC3 in the conjunctiva and lacrimal gland for the first time. Compositions of type 1 and type 3 immune cells were summarized. Our study provides a fundamental reference and novel insights for ocular surface immune homeostasis and diseases.

Conjunctival T Cell Profile in Allogeneic Hematopoietic Stem Cell Transplant Patients after Instilling Topical Cyclosporine-A 0.1% Cationic Emulsion

INTRODUCTION

To profile conjunctival T cell populations in allogeneic hematopoietic stem cell transplant (HSCT) patients after instillation of daily topical cyclosporine-A (CsA) 0.1% cationic emulsion (Ikervis), and to evaluate patients' tolerance to these eye drops.

METHODS

Nineteen participants were prescribed Ikervis prophylaxis once daily to both eyes from 3-5 weeks pre-HSCT to 12 months post-HSCT. The outcome measure was conjunctival T cell proportions from flow cytometry after impression cytology. Covariates included visual acuity, intraocular pressure, slit lamp and fundal examination, dry eye (SPEED) and quality of life questionnaires, non-invasive keratograph tear break-up time (NIKBUT), conjunctival redness, meibography, lipid thickness, Schirmer test, tear cytokines, fluorescein staining, tear osmolarity, and meibomian gland expressibility.

RESULTS

The conjunctival T cell analysis showed either stable or decreased proportions of conjunctival CD4 T cells at the last visit from baseline in compliant patients. CD4 proportions were increased in non-compliant patients and in the single patient who developed ocular graft-versus-host disease (GVHD). All patients were tolerant to Ikervis but 6/19 were not compliant. In the majority of patients, vision did not affect activities of daily living. Pre- and post-HSCT up to the last study visit, there was no statistically significant change in clinical covariates. Only one participant developed ocular GVHD at 9 months post-HSCT.

CONCLUSION

Superficial conjunctival T cell profile reflects compliance to daily topical Ikervis eye drops and clinical ocular surface parameters in allogenic HSCT patients. Tolerance is comparable to other formulations of topical CsA in the first 12 months.

CLINICALTRIALS

GOV IDENTIFIER

NCT04636918. URL: https://clinicaltrials.gov/ct2/show/NCT04636918?cond=ocular+Graft+Versus+Host+Disease&cntry=SG&draw=2&rank=2 .