S100A Proteins as Molecular Targets in the Ocular Surface Inflammatory Diseases

Discovery and Verification of Sjögren's Syndrome Protein Biomarkers in Tears by Targeted LC-MRM

Sjögren's syndrome (SS) is an autoimmune rheumatic disorder characterized by exocrine gland dysfunction, mainly from the lacrimal and salivary glands. The disease causes severe aqueous dry eye syndrome (DED) and is associated with high rates of complications, including corneal ulceration, scaring, and perforation. Systemic complications may occur as well as a higher risk of developing lymphoma. Diagnosis of SS-DED is often delayed and difficult to establish. With the aim of discovering biomarkers to help discriminate SS-DED patients, a combination of untargeted and targeted LC-MS/MS analyses were performed on tear samples collected on Schirmer strips and subjected to tryptic digestion. Following the analysis of three cohorts and the development of two targeted LC-sMRM methods for the verification of putative biomarkers found in the first cohort of samples, 64 proteins could be linked to Sjögren's syndrome, in the hopes of helping to confirm diagnoses as well as potentially stratifying the severity of disease in these patients. Proteins that were increased in SS-DED showed activation of the immune system and alterations in homeostasis. Several proteases and protease inhibitors were found to be significantly changing in SS-DED, as well as a consistent decrease in specific proteins known to be secreted by the lacrimal gland.

In situ tissue profile of rat trigeminal nerve in trigeminal neuralgia using spatial transcriptome sequencing

BACKGROUND

Trigeminal neuralgia (TN) is the most common neuropathic disorder in the maxillofacial region. The etiology and pathogenesis of TN have not been clearly determined to date, although there are many hypotheses.

OBJECTIVE

The goal of this study was to investigate the interactions between different types of cells in TN, particularly the impact and intrinsic mechanism of demyelination on the trigeminal ganglion, and to identify new important target genes and regulatory pathways in TN.

METHODS

TN rat models were prepared by trigeminal root compression, and trigeminal nerve tissues were isolated for spatial transcriptome sequencing. The gene expression matrix was reduced dimensionally by PCA and presented by UMAP. Gene function annotation was analyzed by Metascape. The progression of certain clusters and the developmental pseudotime were analyzed using the Monocle package. Modules of the gene coexpression network between different groups were analyzed based on weighted gene coexpression network analysis and assigned AddModuleScore values. The intercellular communication of genes in these networks via ligand-receptor interactions was analyzed using CellPhoneDB analysis.

RESULTS

The results suggested that the trigeminal ganglion could affect Schwann cell demyelination and remyelination responses through many ligand-receptor interactions, while the effect of Schwann cells on the trigeminal ganglion was much weaker. Additionally, ferroptosis may be involved in the demyelination of Schwann cells.

CONCLUSIONS

This study provides spatial transcriptomics sequencing data on TN, reveals new markers, and redefines the relationship between the ganglion and myelin sheath, providing a theoretical basis and supporting data for future mechanistic research and drug development.

Blastocyst-Derived Lactic Acid May Regulate S100A6 Expression and Function in Mouse Decidualization via Stimulation of Uterine Epithelial Arachidonic Acid Secretion

(1) Background: Inflammatory responses are implicated in embryo implantation, decidualization, pregnancy maintenance and labor. Both embryo implantation and decidualization are essential to successful pregnancy in rodents and primates. S100A6 is involved in inflammation, tumor development, apoptosis and calcium homeostasis. S100A6 is strongly expressed in mouse decidua, but the underlying mechanisms of how S100A6 regulates implantation and decidualization are poorly defined. (2) Methods: Mouse endometrial stromal and epithelial cells are isolated from day 4 pseudopregnant mouse uteri. Both immunofluorescence and Western blotting are used to analyze the expression and localization of proteins. The molecular mechanism is verified in vitro by Western blotting and the quantitative polymerase chain reaction. (3) Results: From days 4 to 8 of pregnancy, S100A6 is specifically expressed in mouse subluminal stromal cells. Blastocyst-derived lactic acid induces AA secretion by activating the luminal epithelial p-cPLA2. The epithelial AA induces stromal S100A6 expression through the COX2/PGI2/PPAR δ pathway. Progesterone regulates S100A6 expression through the progesterone receptor (PR). S100A6/RAGE signaling can regulate decidualization via EGFR/ERK1/2 in vitro. (4) Conclusions: S100A6, as an inflammatory mediator, is important for mouse implantation and decidualization.

Single-cell transcriptomic analysis of corneal organoids during development

Corneal organoids are useful tools for disease modeling and tissue transplantation; however, they have not yet been well studied during maturation. We characterized human iPSC-derived corneal organoids at 1, 2, 3, and 4 months of development using single-cell RNA sequencing to determine the cellular heterogeneity at each stage. We found pluripotent cell clusters committed to epithelial cell lineage at 1 month; early corneal epithelial, endothelial, and stromal cell markers at 2 months; keratocytes as the largest cell population at 3 months; and a large epithelial cell population at 4 months. We compared organoid to fetal corneal development at different stages and found that 4-month organoids closely resemble the corneal cellular complexity of the fetal (16 post conception week) and adult cornea. Using RNA velocity trajectory analysis, we found that less differentiated cells appear to give rise to corneal epithelial cells during development.

Recent Advances in Molecular and Cellular Functions of S100A10

S100A10 (p11, annexin II light chain, calpactin light chain) is a multifunctional protein with a wide range of physiological activity. S100A10 is unique among the S100 family members of proteins since it does not bind to Ca2+, despite its sequence and structural similarity. This review focuses on studies highlighting the structure, regulation, and binding partners of S100A10. The binding partners of S100A10 were collated and summarized.

The functions and regulatory pathways of S100A8/A9 and its receptors in cancers

Inflammation primarily influences the initiation, progression, and deterioration of many human diseases, and immune cells are the principal forces that modulate the balance of inflammation by generating cytokines and chemokines to maintain physiological homeostasis or accelerate disease development. S100A8/A9, a heterodimer protein mainly generated by neutrophils, triggers many signal transduction pathways to mediate microtubule constitution and pathogen defense, as well as intricate procedures of cancer growth, metastasis, drug resistance, and prognosis. Its paired receptors, such as receptor for advanced glycation ends (RAGEs) and toll-like receptor 4 (TLR4), also have roles and effects within tumor cells, mainly involved with mitogen-activated protein kinases (MAPKs), NF-κB, phosphoinositide 3-kinase (PI3K)/Akt, mammalian target of rapamycin (mTOR) and protein kinase C (PKC) activation. In the clinical setting, S100A8/A9 and its receptors can be used complementarily as efficient biomarkers for cancer diagnosis and treatment. This review comprehensively summarizes the biological functions of S100A8/A9 and its various receptors in tumor cells, in order to provide new insights and strategies targeting S100A8/A9 to promote novel diagnostic and therapeutic methods in cancers.

Dioleoylphosphatidylglycerol Inhibits Heat Shock Protein B4 (HSPB4)-Induced Inflammatory Pathways In Vitro

Our previous work shows that dioleoylphosphatidylglycerol (DOPG) accelerates corneal epithelial healing in vitro and in vivo by unknown mechanisms. Prior data demonstrate that DOPG inhibits toll-like receptor (TLR) activation and inflammation induced by microbial components (pathogen-associated molecular patterns, PAMPs) and by endogenous molecules upregulated in psoriatic skin, which act as danger-associated molecular patterns (DAMPs) to activate TLRs and promote inflammation. In the injured cornea, sterile inflammation can result from the release of the DAMP molecule, heat shock protein B4 (HSPB4), to contribute to delayed wound healing. Here, we show in vitro that DOPG inhibits TLR2 activation induced in response to HSPB4, as well as DAMPs that are elevated in diabetes, a disease that also slows corneal wound healing. Further, we show that the co-receptor, cluster of differentiation-14 (CD14), is necessary for PAMP/DAMP-induced activation of TLR2, as well as of TLR4. Finally, we simulated the high-glucose environment of diabetes to show that elevated glucose levels enhance TLR4 activation by a DAMP known to be upregulated in diabetes. Together, our results demonstrate the anti-inflammatory actions of DOPG and support further investigation into its development as a possible therapy for corneal injury, especially in diabetic patients at high risk of vision-threatening complications.

A20 functions as a negative regulator of the lipopolysaccharide-induced inflammation in corneal epithelial cells

A20, also called TNFAIP3, is a crucial regulator of inflammation in various diseases but has not evidenced its function in the cornea. We aimed to evaluate the existence and the functions of A20 in human corneal epithelial (HCE-T) cells. After being treated with lipopolysaccharide (LPS) in different concentrations or at separate times, cells were collected to analyze A20 expressions. We then constructed the A20 knockdown system by siRNA and the A20 overexpressing system by lentivirus transduction. Systems were further exposed to medium with or without LPS for indicated times. Next, we evaluated the production of inflammatory cytokines (IL-6 and IL-8) by qRT-PCR and ELISA. Also, the translocation of P65 and the phosphorylation of P65, P38 and JNK were observed in two systems. In addition, we used the nuclear factor kappa-B (NF-κB) antagonist TPCA-1 for the pretreatment in cells and then detected the A20 expressions. We found a low basal expression of A20 in HCE-T cells, and the expressions could be dose-dependently induced by LPS, peaking at 4 h in protein level after stimulation. Both the A20 knockdown and A20 overexpressing systems were confirmed to be effective. After the LPS treatment, productions of IL-6 and IL-8 were enhanced in the A20 knockdown system and reduced in the A20 overexpressing system. A20 reduced the translocation of P65 into the nucleus and the phosphorylation of P65, P38 and JNK. Furthermore, TPCA-1 pretreatment reduced the expression of A20 in cells. We concluded that A20 is a potent regulator for corneal epithelium's reaction to inflammation, and it thus is expected to be a potential therapy target for ocular surface diseases.

Uncovering the role of transient receptor potential channels in pterygium: a machine learning approach

OBJECTIVES

We aimed at identifying the role of transient receptor potential (TRP) channels in pterygium.

METHODS

Based on microarray data GSE83627 and GSE2513, differentially expressed genes (DEGs) were screened and 20 hub genes were selected. After gene correlation analysis, 5 TRP-related genes were obtained and functional analyses of gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were performed. Multifactor regulatory network including mRNA, microRNAs (miRNAs) and transcription factors (TFs) was constructed. The 5 gene TRP signature for pterygium was validated by multiple machine learning (ML) programs including support vector classifiers (SVC), random forest (RF), and k-nearest neighbors (KNN). Additionally, we outlined the immune microenvironment and analyzed the candidate drugs. Finally, in vitro experiments were performed using human conjunctival epithelial cells (CjECs) to confirm the bioinformatics results.

RESULTS

Five TRP-related genes (MCOLN1, MCOLN3, TRPM3, TRPM6, and TRPM8) were validated by ML algorithms. Functional analyses revealed the participation of lysosome and TRP-regulated inflammatory pathways. A comprehensive immune infiltration landscape and TFs-miRNAs-mRNAs network was studied, which indicated several therapeutic targets (LEF1 and hsa-miR-455-3p). Through correlation analysis, MCOLN3 was proposed as the most promising immune-related biomarker. In vitro experiments further verified the reliability of our in silico results and demonstrated that the 5 TRP-related genes could influence the proliferation and proinflammatory signaling in conjunctival tissue contributing to the pathogenesis of pterygium.

CONCLUSIONS

Our study suggested that TRP channels played an essential role in the pathogenesis of pterygium. The identified pivotal biomarkers (especially MCOLN3) and pathways provide novel directions for future mechanistic and therapeutic studies for pterygium.

Key Genes of Immunity Associated with Pterygium and Primary Sjögren's Syndrome

Pterygium and primary Sjögren's Syndrome (pSS) share many similarities in clinical symptoms and ocular pathophysiological changes, but their etiology is unclear. To identify the potential genes and pathways related to immunity, two published datasets, GSE2513 containing pterygium information and GSE176510 containing pSS information, were selected from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) of pterygium or pSS patients compared with healthy control conjunctiva, and the common DEGs between them were analyzed. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis were conducted for common DEGs. The protein-protein interaction (PPI) network was constructed using the STRING database to find the hub genes, which were verified in clinical samples. There were 14 co-upregulated DEGs. The GO and KEGG analyses showed that these common DEGs were enriched in pathways correlated with virus infection, antigen processing and presentation, nuclear factor-kappa B (NF-κB) and Th17 cell differentiation. The hub genes (IL1R1, ICAM1, IRAK1, S100A9, and S100A8) were selected by PPI construction. In the era of the COVID-19 epidemic, the relationship between virus infection, vaccination, and the incidence of pSS and pterygium growth deserves more attention.

The Potential Role of Regulated Cell Death in Dry Eye Diseases and Ocular Surface Dysfunction

The research on new treatments for dry eye diseases (DED) has exponentially grown over the past decades. The increased prevalence of dry eye conditions, particularly in the younger population, has received much attention. Therefore, it is of utmost importance to identify novel therapeutical targets. Regulated cell death (RCD) is an essential process to control the biological homeostasis of tissues and organisms. The identification of different mechanisms of RCD stimulated the research on their involvement in different human pathologies. Whereas apoptosis has been widely studied in DED and included in the DED vicious cycle, the role of RCD still needs to be completely elucidated. In this review, we will explore the potential roles of different types of RCD in DED and ocular surface dysfunction. Starting from the evidence of oxidative stress and inflammation in dry eye pathology, we will analyse the potential therapeutic applications of the following principal RCD mechanisms: ferroptosis, necroptosis, and pyroptosis.

Innate Immune System Activation, Inflammation and Corneal Wound Healing

Corneal wounds resulting from injury, surgeries, or other intrusions not only cause pain, but also can predispose an individual to infection. While some inflammation may be beneficial to protect against microbial infection of wounds, the inflammatory process, if excessive, may delay corneal wound healing. An examination of the literature on the effect of inflammation on corneal wound healing suggests that manipulations that result in reductions in severe or chronic inflammation lead to better outcomes in terms of corneal clarity, thickness, and healing. However, some acute inflammation is necessary to allow efficient bacterial and fungal clearance and prevent corneal infection. This inflammation can be triggered by microbial components that activate the innate immune system through toll-like receptor (TLR) pathways. In particular, TLR2 and TLR4 activation leads to pro-inflammatory nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) activation. Similarly, endogenous molecules released from disrupted cells, known as damage-associated molecular patterns (DAMPs), can also activate TLR2, TLR4 and NFκB, with the resultant inflammation worsening the outcome of corneal wound healing. In sterile keratitis without infection, inflammation can occur though TLRs to impact corneal wound healing and reduce corneal transparency. This review demonstrates the need for acute inflammation to prevent pathogenic infiltration, while supporting the idea that a reduction in chronic and/or excessive inflammation will allow for improved wound healing.

Construction and Comprehensive Analysis of the ceRNA Network to Reveal Key Genes for Benign Tracheal Stenosis

Objective: To explore the possible biological functions of the differentially expressed genes in patients with benign tracheal stenosis, and to provide a valuable molecular basis for investigating the pathogenesis of benign tracheal stenosis.

Method: Whole transcriptome sequencing was performed on blood samples collected from patients with benign tracheal stenosis and normal controls. Differentially expressed mRNA, lncRNA, and circRNA were analyzed using the DESeq2 package. The protein interaction networks for differentially expressed mRNAs were constructed by STRING. The results of gene co-expression network analysis, Starbase database prediction, and differential gene expression were combined to construct a competing endogenous RNA network. The transcription factors of key genes were predicted using the Network Analyst database and a transcription factor-mRNA regulatory network was constructed. The classical pathways, intermolecular interaction networks, and upstream regulatory components of key genes were analyzed using Ingenuity Pathway Analysis (IPA). Finally, the DGIDB database was used to predict the potential therapeutic drugs to target the identified key genes.

Result: Based on mRNA, lncRNA and circRNA expression data, we found that differentially expressed mRNAs were enriched in oxygen transport, neutrophil activation, immune response, and oxygen binding. Then the pearson correlation between mRNAs of 46 key genes and lncRNAs and cricRNAs were calculated, and the correlation greater than 0.9 were selected to construct the co-expression network of “mRNA-lncRA” and “mRNA-cricRNA.” Moreover, a “lncRNA-miRNA-mRNA” network and a “circRNA-miRNA-mRNA” network were constructed. IPA analysis showed that the 46 key genes were significantly associated with inflammatory activation and acute respiratory distress syndrome. The constructed TF-mRNA regulatory network was composed of 274 nodes and 573 interacting pairs. 251 potential therapeutic drugs were identified from the DGIDB database.

Conclusion: This study analyzed the differential genes associated with benign tracheal stenosis and explored the potential regulatory mechanisms, providing a scientific reference for further studies on the pathogenesis of benign tracheal stenosis.

Tear and ocular surface disease biomarkers: A diagnostic and clinical perspective for ocular allergies and dry eye disease

Validated biomarkers to be used as biological tools for managing ocular surface diseases (OSDs) are still an unmet need in daily clinical practice. Many studies have contributed to the already extensive list of candidate biomarkers for these disorders. Dry eye (DE) and ocular allergy (OA) are complex and multifactorial diseases, often coexisting and with overlapping symptoms. The purpose of this review is to present a comprehensive updated revision of the most relevant biomarkers of DE and OA, with an emphasis on quantitative analyses and correlations with clinical parameter data. Analysis of biomarkers common for these pathologies has highlighted an important physiological process. Namely, the interleukin proteins (IL-1α, IL-1β and IL-17), tumour necrotic factor (TNFα) and interferon gamma (IFNγ; Th1-Th7 pathway) and IL-4, IL-5 and IL-13 (Th2 pathway) seem to represent similar inflammatory mechanisms. Moreover, changes in the levels of mucins (MUC1, MUC2, MUC4, MUC5 and MUC16) are common alterations in the tear film mucous layer. We also examine the current state of medical devices and the main limitations to their use in clinical practice. Translational research in biomarkers for clinical practice depends on a feasible transition from the laboratory to the point-of-care. This requires large-scale, coordinated clinical validation campaigns to select the biomarkers with the highest specificity and sensitivity and significant correlation with clinical parameters. Moreover, technical limitations of multiplexed quantitation systems must be overcome to detect and measure the levels of several biomarkers in very small samples. To ensure the future of biomarker research, significant progress is necessary in a number of fields. There is an urgent need for global unification of clinical classification and diagnostics criteria. Widespread integration of proteomic and transcriptomic data is paramount for performing meaningful analyses using appropriate bioinformatics tools and artificial intelligence systems.

Shotgun Proteomics for the Identification and Profiling of the Tear Proteome of Keratoconus Patients

Purpose

The qualitative approach followed in this study aims to obtain an extensive view of the keratoconus (KC) tear proteome, which could highlight proteins previously undetected and enlarge our knowledge of the disease's pathophysiology.

Methods

Twenty-five patients diagnosed with KC and 25 control subjects were studied in a prospective, cross-sectional study. KC screening examinations, including clinical and tomographic examinations, were performed on all participants. Tear samples were collected using Schirmer strips and analyzed by liquid chromatography-tandem mass spectrometry in a data-dependent workflow. A spectral count was used as a semiquantification tool. The tear proteomes of both groups were identified and profiled, and the functional interactions and biological characterization of differential proteins were analyzed using in silico tools.

Results

We identified a total of 232 proteins, of whom 133 were expressed in both groups’ samples; 41 were observed only in control samples and 58 were identified just in tears of patients with KC. A semiquantitative analysis showed the dysregulation of 17 proteins in the KC samples. An in silico analysis linked proteins only expressed in KC samples to oxidative stress, skin development, and apoptosis. The dysregulation of proteins involved in iron transport, inflammation, oxidative stress, and protease inhibition was observed in the semiquantitative results.

Conclusions

A shotgun analysis showed that the tear proteome of patients with KC differed from controls by more than one-third of the total proteins identified, highlighting the relationship of the proteins only expressed in KC tears with processes of cell death, oxidative damage, and inflammation. The underexpression of proteins involved in iron pathways might support the iron imbalance as a contributing factor to cellular damage and death in KC disease.

Proteomics Analysis of Aqueous Humor and Rejected Graft in Pig-to-Non-Human Primate Corneal Xenotransplantation

Although pig-to-non-human primate (NHP) corneal xenotransplantation has shown long-term graft survival, xenogeneic antigen-related immune responses are still stronger than allogeneic antigen-associated responses. Therefore, there is an unmet need to investigate major rejection pathways in corneal xenotransplantation, even with immunosuppression. This study aimed to identify biomarkers in aqueous humor for predicting rejection and to investigate rejection-related pathways in grafts from NHPs transplanted with porcine corneas following the administration of steroids combined with tacrolimus/rituximab. NHPs who had received corneas from wild-type (WT) or α-1,3-galactosyltransferase gene-knockout (GTKO) pigs were divided into groups with or without rejection according to clinical examinations. Liquid chromatography-mass spectrometry (LC-MS) was used to analyze the proteomes of corneal tissues or aqueous humor. The biological functions of differentially expressed proteins (DEPs) were assessed using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) for pathways and protein–protein interaction network analysis. Among the 66 DEPs in aqueous humor, complement proteins (C3, C5, and C9) and cholesterol metabolic proteins (APOA1 and APOA2) were related to xenogeneic rejection as biomarkers, and alternative pathways of the complement system seemed to be important in xenogeneic graft rejection. Among the 416 DEPs of the cornea, NF-κB1 and proteosomes (PSMD7, PSMA5, and PSMD3) seemed to be related to xenogeneic graft rejection. Additionally, oxidative phosphorylation and leukocyte activation-related pathways are involved in rejection. Overall, our proteomic approach highlights the important role of NF-κB1, proteosomes, oxidative phosphorylation, and leukocyte activation-related inflammation in the cornea and the relevance of complement pathways of the aqueous humor as a predictive biomarker of xenogeneic rejection.

Damage-Associated Molecular Patterns (DAMPs) in Retinal Disorders

Damage-associated molecular patterns (DAMPs) are endogenous danger molecules released from the extracellular and intracellular space of damaged tissue or dead cells. Recent evidence indicates that DAMPs are associated with the sterile inflammation caused by aging, increased ocular pressure, high glucose, oxidative stress, ischemia, mechanical trauma, stress, or environmental conditions, in retinal diseases. DAMPs activate the innate immune system, suggesting their role to be protective, but may promote pathological inflammation and angiogenesis in response to the chronic insult or injury. DAMPs are recognized by specialized innate immune receptors, such as receptors for advanced glycation end products (RAGE), toll-like receptors (TLRs) and the NOD-like receptor family (NLRs), and purine receptor 7 (P2X7), in systemic diseases. However, studies describing the role of DAMPs in retinal disorders are meager. Here, we extensively reviewed the role of DAMPs in retinal disorders, including endophthalmitis, uveitis, glaucoma, ocular cancer, ischemic retinopathies, diabetic retinopathy, age-related macular degeneration, rhegmatogenous retinal detachment, proliferative vitreoretinopathy, and inherited retinal disorders. Finally, we discussed DAMPs as biomarkers, therapeutic targets, and therapeutic agents for retinal disorders.

The prognostic value of S100A calcium binding protein family members in predicting severe forms of COVID-19

Background

Excessive inflammation has been implicated in the immunopathogenesis of coronavirus disease 2019 (COVID-19). In the current study, the involvement of S100 calcium binding protein S100A4, S100A9, and S100A10 in the inflammatory settings of COVID-19 patients were evaluated.

Methods

Peripheral blood samples were obtained from 65 COVID-19 subjects and 50 healthy controls. From the blood samples, RNA was extracted and cDNA was synthesized, and then the mRNA expression levels of S100A4, S100A9, and S100A10 were measured by Real-time PCR.

Results

The mRNA expression of S100A4 (fold change [FC] = 1.45, P = 0.0011), S100A9 (FC = 1.47, P = 0.0013), and S100A10 (FC = 1.35, P = 0.0053) was significantly upregulated in COVID-19 patients than controls. The mRNA expression of S100A4 (FC = 1.43, P = 0.0071), (FC = 1.66, P = 0.0001), and S100A10 (FC = 1.63, P = 0.0003) was significantly upregulated in the severe COVID-19 subjects than mild-to-moderate subjects. There was a significant positive correlation between mRNA expression of S100A4 (ρ = 0.49, P = 0.030), S100A9 (ρ = 0.55, P = 0.009), and S100A10 (ρ = 0.39, P = 0.040) and d-dimer in the COVID-19 patients. The AUC for S100A4, S100A9, and S100A10 mRNAs were 0.79 (95% CI 0.66–0.92, P = 0.004), 0.80 (95% CI 0.67–0.93, P = 0.002), and 0.71 (95% CI 0.56–0.85, P = 0.010), respectively.

Conclusions

S100A4, S100A9, and S100A10 play a role in the inflammatory conditions in COVID-19 patients and have potential in prognosis of severe form of COVID-19. Targeting these modules, hopefully, might confer a therapeutic tool in preventing sever symptoms in the COVID-19 patients.

An Improved Ocular Impression Cytology Method: Quantitative Cell Transfer to Microscope Slides Using a Novel Polymer

PURPOSE

To develop a more efficient impression cytology (IC) method for the transfer of ocular surface cells onto glass microscope slides for cytochemical, immunocytochemical, and immunofluorescence studies.

METHODS

Cells are lifted off the ocular surface with a mixed cellulose ester membrane and then firmly attached to a glass slide using a novel triblock copolymer comprised of collagen type I, polyethylenimine and poly-L-lysine (CPP), and crosslinking cells and glass slide by heating and cooling. The membrane is removed intact after softening it with a butanol/ethanol solution. Transfer of cells is complete in about 10-15 minutes and is ready for staining. The efficiency of our cell transfer method was compared to current methods based on poly-L-lysine and albumin paste.

RESULTS

Our method ensured almost complete transfer of cells. In contrast, the transfer of rabbit conjunctiva cells onto poly-L-lysine-covered slides was 37.5 ± 6.3% lower, and onto albumin-paste covered slides 62.5 ± 5.6% lower (mean ± SD); the transfer of rabbit goblet cells was even less efficient. The new method was also more efficient for transfer of cells from human oral mucosa obtained by IC. Transferred cells were successfully stained with H&E, chemiluminescence, and immunofluorescence agents. Using our method, we stained ocular surface cells for S100A4 and ATF4, both of which play a role in the pathophysiology of dry eye disease. We obtained similar results with oral mucosal cells, suggesting the generalizability of our approach. We propose an explanation for the strong adhesion of cells to the glass slide, which is based on their interactions with the triblock copolymer.

CONCLUSIONS

We developed a novel approach for the efficient and rapid transfer of cells obtained by IC onto glass microscope slides using a novel copolymer. Compared to available methods, our improved approach makes IC robust and simple, and should increase its diagnostic yield and clinical applicability.

Mechanistic Insight Into the Regulation of Immune-Related Genes Expression in Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a severe neurodevelopmental disorder featuring impairment in verbal and non-verbal interactions, defects in social interactions, stereotypic behaviors as well as restricted interests. In recent times, the incidence of ASD is growing at a rapid pace. In spite of great endeavors devoted to explaining ASD pathophysiology, its precise etiology remains unresolved. ASD pathogenesis is related to different phenomena associated with the immune system; however, the mechanisms behind these immune phenomena as well as the potential contributing genes remain unclear. In the current work, we used a bioinformatics approach to describe the role of long non-coding RNA (lncRNA)-associated competing endogenous RNAs (ceRNAs) in the peripheral blood (PB) samples to figure out the molecular regulatory procedures involved in ASD better. The Gene Expression Omnibus database was used to obtain the PB microarray dataset (GSE89594) from the subjects suffering from ASD and control subjects, containing the data related to both mRNAs and lncRNAs. The list of immune-related genes was obtained from the ImmPort database. In order to determine the immune-related differentially expressed mRNAs (DEmRNAs) and lncRNAs (DElncRNAs), the limma package of R software was used. A protein-protein interaction network was developed for the immune-related DEmRNAs. By employing the Human MicroRNA Disease Database, DIANA-LncBase, and DIANA-TarBase databases, the RNA interaction pairs were determined. We used the Pearson correlation coefficient to discover the positive correlations between DElncRNAs and DEmRNAs within the ceRNA network. Finally, the lncRNA-associated ceRNA network was created based on DElncRNA-miRNA-DEmRNA interactions and co-expression interactions. In addition, the KEGG enrichment analysis was conducted for immune-related DEmRNAs found within the constructed network. This work found four potential DElncRNA-miRNA-DEmRNA axes in ASD pathogenesis, including, LINC00472/hsa-miR-221-3p/PTPN11, ANP32A-IT1/hsa-miR-182-5p/S100A2, LINC00472/hsa-miR-132-3p/S100A2, and RBM26-AS1/hsa-miR-182-5p/S100A2. According to pathway enrichment analysis, the immune-related DEmRNAs were enriched in the "JAK-STAT signaling pathway" and "Adipocytokine signaling pathway." An understanding of regulatory mechanisms of ASD-related immune genes would provide novel insights into the molecular mechanisms behind ASD pathogenesis.

Clinical parameters and biological markers associated with acute severe ocular complications in Stevens-Johnson syndrome and toxic epidermal necrolysis

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are severe cutaneous adverse drug reactions with high mortality rates. Its sequelae, such as blindness, persist even after recovery. Patients with SJS/TEN should be accurately diagnosed and receive appropriate treatment as soon as possible. Therefore, identifying the factors for severity prediction is necessary. We aimed to clarify the clinical parameters and biological markers that can predict acute severe ocular complications (SOCs) in SJS/TEN. This retrospective cross-sectional study enrolled 47 patients with SJS/TEN who were divided into two groups according to ocular severity at acute onset: non-severe ocular complications group (n = 27) and severe ocular complications group (n = 20). Multivariate logistic regression analysis revealed that disease severity (body surface area detachment ≥ 10%) was a predictive factor for acute SOCs, and older age (≥ 60 years) was marginally significantly predictive of SOCs. Serum biomarker levels of S100A8/A9 and granulysin were marginally significant and tended to increase in the SOC group. Therefore, during the early acute stage, focusing on disease severity, patient age, and serum inflammatory biomarkers (S100A8/A9 and granulysin) might help predict SOC progression in patients with SJS/TEN who need prompt and aggressive ocular management to prevent severe ocular sequelae.

Comprehensive analysis of the transcriptional expressions and prognostic value of S100A family in pancreatic ductal adenocarcinoma

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) remains a treatment-refractory malignancy with poor prognosis. It is urgent to identify novel and valid biomarkers to predict the progress and prognosis of PDAC. The S100A family have been identified as being involved in cell proliferation, migration and differentiation progression of various cancer types. However, the expression patterns and prognostic values of S100As in PDAC remain to be analyzed.

METHODS

We investigated the transcriptional expressions, methylation level and prognostic value of S100As in PDAC patients from the Oncomine, GEPIA2, Linkedomics and cBioPortal databases. Real-time PCR was used to detect the expressions of S100A2/4/6/10/14/16 in four pancreatic cancer cell lines and pancreatic cancer tissues from PDAC patients undergoing surgery. To verify the results further, immunohistochemistry was used to measure the expression of S100A2/4/6/10/14/16 in 43 PDAC patients' tissue samples. The drug relations of S100As were analyzed by using the Drugbank database.

RESULTS

The results suggested that, the expression levels of S100A2/4/6/10/14/16 were elevated to PDAC tissues than in normal pancreatic tissues, and the promoter methylation levels of S100A S100A2/4/6/10/14/16 in PDAC (n = 10) were lower compared with normal tissue (n = 184) (P < 0.05). In addition, their expressions were negatively correlated with PDAC patient survival.

CONCLUSIONS

Taken together, these results suggest that S100A2/4/6/10/14/16 might be served as prognostic biomarkers for survivals of PDAC patients.

The transcriptome of rabbit conjunctiva in dry eye disease: Large-scale changes and similarity to the human dry eye

The pathophysiology of dry eye disease (DED) remains largely unknown, accounting in part for the lack of successful treatments. We explored the pathophysiology of DED using a rabbit model of chronic DED induced with 3 weekly injections of Concanavalin A into the periorbital lacrimal glands. The transcriptome of full-thickness's conjunctival tissue from rabbits with DED and from normal controls was determined using microarrays and, as needed, confirmatory real-time polymerase chain reactions. Results were subjected to bioinformatic analysis. DED induced large-scale changes in gene transcription involving 5,184 genes (22% of the total). Differentially expressed genes could be segregated into: functional modules and clusters; altered pathways; functionally linked genes; and groups of individual genes of known or suspected pathophysiological relevance to DED. A common feature of these subgroups is the breadth and magnitude of the changes that encompass ocular immunology and essentially all aspects of cell biology. Prominent changes concerned innate and adaptive immune responses; ocular surface inflammation; at least 25 significantly altered signaling pathways; a large number of chemokines; cell cycle; and apoptosis. Comparison of our findings to the limited extant transcriptomic data from DED patients associated with either Sjogren's syndrome or non-Sjogren's etiologies revealed a significant correlation between human and rabbit DED transcriptomes. Our data, establishing the large-scale transcriptomic changes of DED and their potential similarity to the human, underscore the enormous complexity of DED; establish a robust animal model of DED; will help expand our understanding of its pathophysiology; and could guide the development of successful therapeutic strategies.

S100 Calcium Binding Protein A10, A Novel Oncogene, Promotes the Proliferation, Invasion, and Migration of Hepatocellular Carcinoma

Hepatocarcinogenesis is a highly complicated process that is promoted by a series of oncogenes. Our study aims to identify novel oncogenes promoting hepatocellular carcinoma (HCC) by bioinformatic analysis and experimental validation. Here, we reported that S100 calcium binding protein A10 (S100A10) was screened out as a potential novel oncogene in HCC by integrated analysis of OEP000321 dataset and the Cancer Genome Atlas (TCGA)-Liver-Cancer data. Furthermore, S100A10 was highly expressed in HCC samples and observably associated with patients’ overall survival (OS). Overexpression of S100A10 in Hep3B and Huh-7 increased the cell proliferation, whereas downregulation of S100A10 in SK-Hep-1 and HepG2 cells reduced the cell viability to almost stop growing. In vivo tumor growth assays showed that S100A10-overexpressing Hep3B cells had a larger tumor size than control. Moreover, S100A10 overexpression promoted Hep3B cells migration and invasion, and S100A10 knockdown inhibited SK-Hep-1 cells migration and invasion, in vitro. In conclusion, it is demonstrated that S100A10 is a novel oncogene in HCC, indicating a possible novel therapeutic strategy of HCC.

S100A gene family: immune-related prognostic biomarkers and therapeutic targets for low-grade glioma

BACKGROUND

Despite the better prognosis given by surgical resection and chemotherapy in low-grade glioma (LGG), progressive transformation is still a huge concern. In this case, the S100A gene family, being capable of regulating inflammatory responses, can promote tumor development.

METHODS

The analysis was carried out via ONCOMINE, GEPIA, cBioPortal, String, GeneMANIA, WebGestalt, LinkedOmics, TIMER, CGGA, R 4.0.2 and immunohistochemistry.

RESULTS

S100A2, S100A6, S100A10, S100A11, and S100A16 were up-regulated and S100A1 and S100A13 were down-regulated in LGG compared to normal tissues. S100A3, S100A4, S100A8, and S100A9 expression was up-regulated during the progression of glioma grade. In addition, genetic variation of the S100A family was high in LGG, and the S100A family genes mostly function through IL-17 signaling pathway, S100 binding protein, and inflammatory responses. The TIMER database also revealed a relationship between gene expression and immune cell infiltration. High expression of S100A2, S100A3, S100A4, S100A6, S100A8, S100A9, S100A10, S100A11, S100A13, and S100A16 was significantly associated with poor prognosis in LGG patients. S100A family genes S100A2, S100A3, S100A6, S100A10, and S100A11 may be prognosis-related genes in LGG, and were significantly associated with IDH mutation and 1p19q codeletion. The immunohistochemical staining results also confirmed that S100A2, S100A3, S100A6, S100A10, and S100A11 expression was upregulated in LGG.

CONCLUSION

The S100A family plays a vital role in LGG pathogenesis, presumably facilitating LGG progression via modulating inflammatory state and immune cell infiltration.

The ocular surface immune system through the eyes of aging

Since the last century, advances in healthcare, housing, and education have led to an increase in life expectancy. Longevity is accompanied by a higher prevalence of age-related diseases, such as cancer, autoimmunity, diabetes, and infection, and part of this increase in disease incidence relates to the significant changes that aging brings about in the immune system. The eye is not spared by aging either, presenting with age-related disorders of its own, and interestingly, many of these diseases have immune pathophysiology. Being delicate organs that must be exposed to the environment in order to capture light, the eyes are endowed with a mucosal environment that protects them, the so-called ocular surface. As in other mucosal sites, immune responses at the ocular surface need to be swift and potent to eliminate threats but are at the same time tightly controlled to prevent excessive inflammation and bystander damage. This review will detail how aging affects the mucosal immune response of the ocular surface as a whole and how this process relates to the higher incidence of ocular surface disease in the elderly.

S100A4 Silencing Facilitates Corneal Wound Healing After Alkali Burns by Promoting Autophagy via Blocking the PI3K/Akt/mTOR Signaling Pathway

Purpose

This study investigated the role of S100 calcium binding protein A4 (S100A4) in corneal wound healing and the underlying mechanism of the S100A4-mediated PI3K/Akt/mammalian target of rapamycin (mTOR) pathway.

Methods

The rabbit corneal alkali burn model was established in vivo. S100A4 expression, wound healing, inflammation, and autophagy in rabbit cornea after alkali burn were detected. The NaOH-treated rabbit corneal stromal cells (rCSCs) were transfected with overexpressed S100A4 or silencing S100A4 to examine the effect of S100A4 on corneal wound healing in vitro. The effect of S100A4 on cell viability, proliferation, migration, invasion, fibrosis, and autophagy of rCSCs after alkali burn was analyzed. Then the functional rescue experiments were carried out. The PI3K inhibitor, LY294002, was used to elucidate the PI3K/Akt/mTOR signaling pathway in rCSCs.

Results

S100A4 silencing promoted rabbit corneal wound healing by inhibiting fibrosis and inflammation and promoting autophagy in alkali-burned cornea, corresponding to increased levels of LC3, Beclin 1, and Atg4B but lowered α-smooth muscle actin, TNF-ɑ, and p62 levels. Moreover, silencing S100A4 inhibited proliferation, migration, invasion, and fibrosis of NaOH-treated rCSCs and promoted the differentiation of rCSCs into corneal cells and the autophagy of damaged rCSCs. The inhibitory role of S100A4 in wound healing was achieved via activation of the PI3K/Akt/mTOR pathway.

Conclusions

S100A4 silencing confers a promising effect on wound healing of alkali-burned cornea by blocking the PI3K/Akt/mTOR pathway, supporting the advancement of corneal gene therapies for wound healing.

Antimicrobial Peptides Derived from the Immune Defense Protein CAP37 Inhibit TLR4 Activation by S100A9

Purpose

Corneal abrasion is a common eye injury, and its resolution can be seriously complicated by bacterial infection. We showed that topical application of the cationic antimicrobial protein of 37 kDa (CAP37) promotes corneal re-epithelialization in mice, and peptides derived from CAP37 can recapitulate the antibacterial and wound-healing effects of the full-length protein. The current study was designed to identify the molecular mechanisms mediating the wound-healing effect of CAP37 and derived bioactive peptides.

Methods

We used a TriCEPS-based, ligand-receptor glycocapture method to identify the binding partners of CAP37 on live human corneal epithelial cells using the hTCEpi cell line. We used an ELISA method to confirm binding with identified partners and test the binding with CAP37-derived peptides. We used a reporter cell line to measure activation of the identified membrane receptor by CAP37 and derived peptides.

Results

We pulled down S100 calcium-binding protein A9 (S100A9) as a binding partner of CAP37 and found that CAP37 and four derived peptides encompassing two regions of CAP37 bind S100A9 with high affinities. We found that CAP37 and the S100A9-binding peptides could also directly interact with the Toll-like receptor 4 (TLR4), a known receptor for S100A9. CAP37 and one peptide partially activated TLR4. The other three peptides did not activate TLR4. Finally, we found that CAP37 and all four peptides could inhibit the activation of TLR4 by S100A9.

Conclusions

This study identifies a mechanism of action for CAP37 and derived antimicrobial peptides that may restrain inflammatory responses to corneal injury and favor corneal re-epithelialization.

Antigen-presenting cells in ocular surface diseases

PURPOSE

To review the role of antigen-presenting cells (APC) in the pathogenesis of ocular surface diseases (OSD).

METHODS

A thorough literature search was performed in PubMed database. An additional search was made in Google Scholar to complete the collected items.

RESULTS

APCs have the ability to initiate and direct immune responses and are found in most lymphoid and non-lymphoid tissues. APCs continuously sample their environment, present antigens to T cells and co-ordinate immune tolerance and responses. Many different types of APCs have been described and there is growing evidence that these cells are involved in the pathogenesis of OSD. OSD is a complex term for a myriad of disorders that are often characterized by ocular surface inflammation, tear film instability and impairment of vision.

CONCLUSIONS

This review summarizes the current knowledge concerning the immunotopographical distribution of APCs in the normal ocular surface. APCs appear to play a critical role in the pathology of a number of conditions associated with OSD including infectious keratitis, ocular allergy, dry eye disease and pterygium.

Adverse reproductive effects of S100A9 on bovine sperm and early embryonic development in vitro

The phenomenon of aging arises from multiple, complex interactions causing dysfunction in cells and organs. In particular, fertility drastically decreases with age. Previously, we have demonstrated that the functional characteristics of the bovine oviduct and uterus change with the age-dependent upregulation of inflammation and noted that S100A9 triggers inflammatory responses in oviduct epithelial cells. In the present study, we investigated the hypothesis that S100A9 affects reproductive events to aspect such as sperm function, fertilization, and the development of the embryo in cows. To investigate the effect of S100A9 on bovine sperm, we incubated sperms in vitro with S100A9 for 5 h and observed significantly decreased sperm motility and viability. During in vitro fertilization, S100A9 treatment for 5 h did not affect the rate of fertilization, time of first division of embryos, or embryo development to blastocyst stage. Treatment of 2-cell stage embryos with S100A9 for 5 h significantly reduced the proportion of cells undergoing normal division (4-8 cell embryos) and embryo development to the blastocyst stage. In experiment involving 24 h treatment of 2-cell embryos, the development of all embryos stopped at the 2-cell stage in the S100A9-treated group. In blastocyst-stage embryos, S100A9 treatment significantly stimulated the expression of endoplasmic reticulum (ER) and the mRNA expression of ER stress markers, and activated caspase-3 with subsequent nuclear fragmentation. Pre-treatment with an ER stress inhibitor significantly suppressed caspase-3 activation by the S100A9 treatment, suggesting that S100A9 induces blastocyst dysfunction by apoptosis (via caspase-3 activation) depending on ER stress. These results indicate that direct exposure to S100A9 exerted adverse effects on sperm function and embryo development. These findings suggest that excessive dose of S100A9 may have an adverse effect to the reproductive machinery by inducing inflammation and tissue dysfunction.

The Innate Immune Cell Profile of the Cornea Predicts the Onset of Ocular Surface Inflammatory Disorders

Ocular surface inflammatory disorder (OSID) is a spectrum of disorders that have features of several etiologies whilst displaying similar phenotypic signs of ocular inflammation. They are complicated disorders with underlying mechanisms related to several autoimmune disorders, such as rheumatoid arthritis (RA), Sjögren’s syndrome, and systemic lupus erythematosus (SLE). Current literature shows the involvement of both innate and adaptive arms of the immune system in ocular surface inflammation. The ocular surface contains distinct components of the immune system in the conjunctiva and the cornea. The normal conjunctiva epithelium and sub-epithelial stroma contains resident immune cells, such as T cells, B cells (adaptive), dendritic cells, and macrophages (innate). The relative sterile environment of the cornea is achieved by the tolerogenic properties of dendritic cells in the conjunctiva, the presence of regulatory lymphocytes, and the existence of soluble immunosuppressive factors, such as the transforming growth factor (TGF)-β and macrophage migration inhibitory factors. With the presence of both innate and adaptive immune system components, it is intriguing to investigate the most important leukocyte population in the ocular surface, which is involved in immune surveillance. Our meta-analysis investigates into this with a focus on both infectious (contact lens wear, corneal graft rejection, Cytomegalovirus, keratitis, scleritis, ocular surgery) and non-infectious (dry eye disease, glaucoma, graft-vs-host disease, Sjögren’s syndrome) situations. We have found the predominance of dendritic cells in ocular surface diseases, along with the Th-related cytokines. Our goal is to improve the knowledge of immune cells in OSID and to open new dimensions in the field. The purpose of this study is not to limit ourselves in the ocular system, but to investigate the importance of dendritic cells in the disorders of other mucosal organs (e.g., lungs, gut, uterus). Holistically, we want to investigate if this is a common trend in the initiation of any disease related to the mucosal organs and find a unified therapeutic approach. In addition, we want to show the power of computational approaches to foster a collaboration between computational and biological science.

S100A6 Promotes B Lymphocyte Penetration Through the Blood-Brain Barrier in Autoimmune Encephalitis

Autoimmune encephalitis (AE) is a severe neurological disease. The brain of the AE patient is attacked by a dysregulated immune system, which is caused by the excessive production of autoantibodies against neuronal receptors and synaptic proteins. AE is also characterized by the uncontrolled B lymphocyte infiltration through the blood–brain barrier (BBB) layer, and the investigation of the underlying mechanism involved in this infiltration may facilitate the discovery of novel therapies for AE. However, few AE-related studies have focused on this issue. In this study, we aimed to identify the factors involved in B lymphocyte infiltration in AE. For this purpose, we first enrolled four healthy control and five AE subjects, collecting their serum and/or total white blood cell samples. The white blood cell samples were further used for collecting RNA and DNA. Then, we simulated the in vivo B lymphocyte infiltration with an in vitro leukocyte transendothelial migration model. It turned out that AE serum treatment significantly and specifically promoted B cells to penetrate the BBB endothelial layer without affecting neutrophils. Next, through genome-wide DNA methylation assays on bisulfite-conversion DNA samples, we identified S100A6 and S100A11 as potential hypo-methylated disease genes in the AE samples. Further qPCR assays demonstrated their upregulation in AE samples, reflecting the negative correlations between gene expression and DNA methylation. Finally, recombinant S100A6 protein treatment significantly increased B lymphocyte infiltration through the BBB endothelial layer, which partially recapitulated the effect of AE serum. In summary, by using an in vitro leukocyte transendothelial migration model, we confirmed that S100A6 promoted B lymphocyte to penetrate the BBB endothelial layer, which is similar to the in vivo clinical manifestations of AE. Therefore, further studies on how the S100A6 protein facilitates B lymphocyte infiltration and on whether other factors in serum also contribute to this phenomenon are likely to improve our understanding of AE and hopefully to reveal novel therapeutic targets for this emerging treatable neurological disorder.

S100A10 silencing suppresses proliferation, migration and invasion of ovarian cancer cells and enhances sensitivity to carboplatin

Background

Ovarian cancer is the leading cause of gynecological cancer-related mortality. The novel oncogene S100A10 has been reported to be involved in cancer cell proliferation, invasion and metastasis. The role of S100A10 in ovarian cancer has not been well studied and the effect of S100A10 on chemotherapy remains unclear. The aims of the present study were to investigate the functional role of S100A10 in the progression and carboplatin sensitivity of ovarian cancer.

Methods

We examined the expression levels in tissues of S100A10 in 138 cases of ovarian cancer by IHC. To determine the functional roles of downregulated S100A10 in ovarian cancer, cell proliferation, colony formation, cell migration and invasion assays were performed. Chemoresistance was analyzed by apoptosis assay. A xenograft tumor model was established to confirm the role of S100A10 in carboplatin resistance in vivo. Using Western blot assays, we also explored the possible mechanisms of S100A10 in ovarian cancer.

Results

The results showed that increased expression of S100A10 was positively associated with carboplatin resistance (P < 0.001), tumor grade (P = 0.048) and a poorer prognosis (P = 0.0053). Functional analyses demonstrated that S100A10 suppression significantly suppressed ovarian cancer cell proliferation, colony formation, cell migration and invasion, remarkably increased carboplatin-induced apoptosis in SKOV3 and A2780 cells and inhibited tumor growth in vivo. Downregulation of S100A10 expression could inhibit cell proliferation and enhance ovarian cancer cell sensitivity to carboplatin, possibly involving the regulation of cleaved-Caspase3 and cleaved-PARP.

Conclusions

Together, the results of the present study reveal that S100A10 expression can be used as a predictive marker for the prognosis of ovarian cancer and chemosensitivity to carboplatin.

Fungal keratitis: Pathogenesis, diagnosis and prevention

As a kind of serious, potentially sight-threatening corneal infections with poor prognosis, fungal keratitis can bring a heavy economic burden to patients and seriously affect the quality of life, especially those in developing countries where fungal keratitis is more prevalent. Typical clinical features include immune rings, satellite lesions, pseudopods, hypha moss, hypopyon and endothelial plaques. The ideal therapeutic effects could not be achieved by current treatments for many reasons. Therefore, under the current status, understanding the pathogenesis, early diagnosis and prevention strategies might be of great importance. Here, in this review, we discuss the recent progresses that may advance our understanding of pathogenesis, early diagnosis and prevention of fungal keratitis.

Tear Lactoferrin and Features of Ocular Allergy in Different Severities of Meibomian Gland Dysfunction

SIGNIFICANCE

Meibomian gland dysfunction, but not atrophy, was associated with lower tear lactoferrin concentration, greater dry eye, and allergic symptoms, indicating greater inflammation and discomfort in patients with lower meibomian gland expressibility.

PURPOSE

Meibomian gland dysfunction can potentially damage adjacent palpebral structures, which may induce inflammation in accessory lacrimal glands and affect lactoferrin secretion. This study aimed to examine the relationships between the severity of meibomian gland dysfunction with tear lactoferrin, conjunctival cell morphology, and clinical features of ocular allergy.

METHODS

Forty subjects were divided into two groups based on the severity of meibomian gland plugging and expressibility and secondarily based on its atrophy. Dry eye and allergy questionnaires; slit-lamp examination, including lid telangiectasia; and meibography were performed. Tear lactoferrin concentration was measured using TearScan 270 MicroAssay. Impression cytology was performed on the upper palpebral conjunctiva, and goblet cell density and epithelial squamous metaplasia were quantified.

RESULTS

Twenty-two subjects with meibomian gland dysfunction were categorized into severely obstructed group (case), whereas 19 subjects had minimal/no obstruction (comparison). Lower lactoferrin (1.3 ± 0.4 vs. 1.7 ± 0.4 mg/mL, P = .007), greater dry eye (7 [1 to 10] vs. 2 [0 to 5], P = .03), and allergy symptoms (9 [4 to 23] vs. 6 [0 to 9], P = .05) were found in the cases compared with the comparisons. There were no differences in conjunctival cell morphology between groups. The plugging score was correlated with lactoferrin concentration (ρ = -0.43, P = .006), dry eye (ρ = 0.36, P = .02), and allergic symptoms (ρ = 0.33, P = .04). Greater lid margin telangiectasia was associated with meibomian gland obstruction, but not atrophy.

CONCLUSIONS

Meibomian gland activity/dysfunction, but not atrophy, may be associated with increased inflammation on the ocular surface. The inflammation may be sufficient to reduce tear lactoferrin production from damage to accessory lacrimal glands and/or meibomian gland and result in increased symptoms.

Age-associated changes in human tear proteome

Background

Prevalence of many eye and ocular surface diseases increases with age. While the clinical characteristics and pathophysiologic mechanisms of these conditions are often either known or extensively studied, the effects of normal aging on tear film and ocular surface have not been as widely researched.

Methods

In order to examine the effects of aging on tear fluid proteomics, tear fluid samples were collected preoperatively from 115 subjects undergoing strabismus or refractive surgery using glass microcapillary tubes. In addition to their refractive error or strabismus, the subjects did not have any other current, known eye diseases. The non-pooled samples were analysed using NanoLC-TripleTOF implementing a sequential window acquisition of all theoretical fragment ion spectra mass spectrometry, resulting in quantified data of 849 proteins.

Results

According to correlation results, 17 tear proteins correlated significantly with increased age and many of these proteins were connected to inflammation, immune response and cell death. According to enrichment analysis, growth and survival of cells decreased while immune response and inflammation increased with aging. We also discovered several well-known, activated and inhibited upstream regulators, e.g. NF-κB, which has been previously connected to aging in numerous previous studies.

Conclusions

Overall, the results show the common age-dependent alterations in tear fluid protein profile, which demonstrate similar age-associated alterations of biological functions previously shown in other tissue and sample types.

Electronic supplementary material

The online version of this article (10.1186/s12014-019-9233-5) contains supplementary material, which is available to authorized users.

Correlation between systemic S100A8 and S100A9 levels and severity of diabetic retinopathy in patients with type 2 diabetes mellitus

AIMS

S100A8 and S100A9 are myeloid-related damage-associated molecular patterns (DAMPs) primarily involved in the modulation of innate immune response to cellular injury. This study evaluated the correlation between circulating concentrations of S100A8 and S100A9 proteins with the severity of diabetic retinopathy (DR) in patients with type 2 diabetes (T2DM).

METHODS

T2DM patients with HbA1c levels >7%, fasting blood glucose >126 mg/dl and history of diabetes were included in this study. DR severity was graded based on ETDRS and Gloucestershire classifications. Plasma samples were evaluated for S100A8 and S100A9 levels using ELISA.

RESULTS

In this comparative study, DR patients (n = 89) had increased plasma S100A8 and S100A9 proteins compared to age-matched T2DM controls (n = 28), which was directly related to the severity of DR. Female DR subjects had increased S100A8 expression compared to their male counterparts. Substantial retention of S100A8 and S100A9 production was seen in DR patients above 50 years of age. Duration of T2DM was not found to affect protein levels, however T2DM onset at >50 years old significantly increased S100A8 and S100A9 concentrations.

CONCLUSIONS

Our findings suggest that systemic circulation levels of S100A8 and S100A9 are correlated with the progression of DR in T2DM patients, indicating their potential role in DR pathogenesis.

Ocular surface pathogenesis associated with precocious eyelid opening and necrotic autologous tissue in mouse with disruption of Prickle 1 gene

Ocular surface disease is one major type of eye diseases. Different etiologies trigger distinct pathological responses of the ocular surface. We previously reported that genetically engineered mice with ablation of Prickle 1 manifested precocious eyelid opening with ensuing cornea dysplasia. The current study aimed to characterize the molecular traits and the direct cause of ocular pathology associated with precocious eyelid opening in the Prickle 1 mutant mouse. Prickle 1 mutant mice exhibited a slew of ocular surface pathology including cell proliferation, cell fate transformation and inflammatory infiltration coinciding with the timing of the precocious eyelid opening. Forced eyelid opening in wild type mice did not induce cornea pathology comparable to that of the Prickle 1 mutants. Necrotic tissue debris was found associated with the lesioned cornea. RNAseq analysis of the mutant cornea revealed an expression profile shared by a range of dermatological diseases involving immune responses and cancer. Taken together, the data suggest that the necrotic eyelid debris plays an important role in ocular pathogenesis of the Prickle 1 mutant mouse, which may represent a type of non-infectious keratoconjunctivitis caused by damaged autologous tissues. Additionally, Prickle 1 mutant cornea pathogenesis may offer molecular insights into other types of epithelial pathogenesis.

Tear Proteins Calcium binding protein A4 (S100A4) and Prolactin Induced Protein (PIP) are Potential Biomarkers for Thyroid Eye Disease

There are no reliable biomarkers to predict thyroid eye disease (TED) in patients with autoimmune thyroid disease (AITD) currently. Several evidences support the involvement of the lacrimal gland in TED. The aim of our study was to quantitatively correlate the changes in tear protein profile with increasing severity of TED. Tear samples were collected from four groups of patients; AITD without TED (AITD), AITD with mild TED (mild TED), AITD with severe TED (severe TED) and normal controls. A total of 72 patients were recruited for the study. In discovery phase, isobaric tags for relative and absolute quantification (iTRAQ) 4-plex was used for quantitative proteomics analysis. For verification of results from discovery phase, sequential window acquisition of all theoretical fragment ion spectra (SWATH) was used to analyze an independent cohort from normal controls, AITD, mild TED and severe TED. Two proteins, S100A4 and PIP showed consistent dysregulation trends in the discovery and validation phase experiments. Our study demonstrated the differences in tear proteome across the spectrum of different severity and activity of TED in patients with AITD. Two tear proteins, S100A4 and PIP may serve as potential biomarkers to predict progression to severe TED in patients with AITD.

Interaction of S100A1 with LATS1 promotes cell growth through regulation of the Hippo pathway in hepatocellular carcinoma

Despite advances in surgery and chemotherapy, the prognosis of patients with hepatocellular carcinoma (HCC) remains poor. In the present study, the role of S100A1 in the progression of HCC was investigated. Immunohistochemical staining was used to measure the expression of S100A1 in HCC tissues. S100A1 was knocked down by siRNA. A battery of experiments was used to evaluate the biology functions of S100A1. It was found that S100A1 was upregulated in HCC tissues, and its upregulation was associated with a large tumor size, low differentiation and shorter survival time. The biological experiments demonstrated that S100A1 functions as an oncogene in HCC. It was also found that S100A1 knockdown enhanced the inhibitory effects of cisplatin on HCC cells. The results showed that the downregulation of S100A1 induced the phosphorylation of yes‑associated protein (YAP), and treatment with CHX demonstrated that the downregulation of S100A1 accelerated YAP protein degradation. The downregulation of S100A1 did not alter the expression of mammalian sterile 20‑like kinase (MST)1/2 or phosphorylated MST1/2, but upregulated the phosphorylation of large tumor suppressor kinase 1 (LATS1). It was further confirmed that S100A1 interacted with LATS1. LATS1 depletion significantly reduced the effects of S100A1 on cell growth rate and apoptosis, and there was a positive correlation between phosphorylated LATS1 and S100A1 in clinical samples, indicating that LATS1 was responsible for the S100A1-induced changes in cancer cell growth and Hippo signaling. In conclusion, the results of the present study indicated that S100A1 functions as an oncogene and may be a biomarker for the prognosis of patients with HCC. S100A1 exerted its oncogenic function by interacting with LATS1 and activating YAP. S100A1 may serve as a target for novel therapies in HCC.

Tubulin-dependent secretion of S100A6 and cellular signaling pathways activated by S100A6-integrin β1 interaction

S100A6 is a calcium binding protein expressed mainly in fibroblasts and epithelial cells. Interestingly, S100A6 is also present in extracellular fluids. Recently we have shown that S100A6 is secreted by WJMS cells and binds to integrin β1 (Jurewicz et al., 2014). In this work we describe for the first time the mechanism of S100A6 secretion and signaling pathways activated by the S100A6-integrin β1 complex. We show that colchicine suppressed the release of S100A6 into the cell medium, which indicates that the protein might be secreted via a tubulin-dependent pathway. By applying double immunogold labeling and immunofluorescence staining we have shown that S100A6 associates with microtubules in WJMS cells. Furthermore, results obtained from immunoprecipitation and proximity ligation assay (PLA), and from in vitro assays, reveal that S100A6 is able to form complexes with α and β tubulin in these cells, and that the S100A6-tubulin interaction is direct. We have also found that the S100A6 protein, due to binding to integrin β1, activates integrin-linked kinase (ILK), focal adhesion kinase (FAK) and p21-activated kinase (PAK). Our results suggest that binding of S100A6 to integrin β1 affects cell adhesion/proliferation due to activation of ILK and FAK signaling pathways.

An Ocular Commensal Protects against Corneal Infection by Driving an Interleukin-17 Response from Mucosal γδ T Cells

Mucosal sites such as the intestine, oral cavity, nasopharynx, and vagina all have associated commensal flora. The surface of the eye is also a mucosal site, but proof of a living, resident ocular microbiome remains elusive. Here, we used a mouse model of ocular surface disease to reveal that commensals were present in the ocular mucosa and had functional immunological consequences. We isolated one such candidate commensal, Corynebacterium mastitidis, and showed that this organism elicited a commensal-specific interleukin-17 response from γδ T cells in the ocular mucosa that was central to local immunity. The commensal-specific response drove neutrophil recruitment and the release of antimicrobials into the tears and protected the eye from pathogenic Candida albicans or Pseudomonas aeruginosa infection. Our findings provide direct evidence that a resident commensal microbiome exists on the ocular surface and identify the cellular mechanisms underlying its effects on ocular immune homeostasis and host defense.