Insights into the role of fibroblasts in human autoimmune diseases

Extreme Tolerance of Extraocular Muscles to Diseases and Aging: Why and How?

The extraocular muscles (EOMs) possess unique characteristics that set them apart from other skeletal muscles. These muscles, responsible for eye movements, exhibit remarkable resistance to various muscular dystrophies and aging, presenting a significant contrast to the vulnerability of skeletal muscles to these conditions. In this review, we delve into the cellular and molecular underpinnings of the distinct properties of EOMs. We explore their structural complexity, highlighting differences in fiber types, innervation patterns, and developmental origins. Notably, EOM fibers express a diverse array of myosin heavy-chain isoforms, retaining embryonic forms into adulthood. Moreover, their motor innervation is characterized by a high ratio of nerve fibers to muscle fibers and the presence of unique neuromuscular junctions. These features contribute to the specialized functions of EOMs, including rapid and precise eye movements. Understanding the mechanisms behind the resilience of EOMs to disease and aging may offer insights into potential therapeutic strategies for treating muscular dystrophies and myopathies affecting other skeletal muscles.

Identification of immune-related regulatory networks and diagnostic biomarkers in thyroid eye disease

BACKGROUND

Thyroid eye disease (TED) is an orbit-associated autoimmune inflammatory disorder intricately linked to immune dysregulation. Complete pathogenesis of TED remains elusive. This work aimed to mine pathogenesis of TED from immunological perspective and identify diagnostic genes.

METHODS

Gene expression microarray data for TED patients were downloaded from Gene Expression Omnibus, immune-related genes (IRGs) were from ImmPort database, and TED-related transcription factors (TFs) were from Cirtrome Cancer database. Differential analysis, Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed. Regulatory networks of TFs and IRGs were constructed with Cytoscape. Diagnostic biomarkers in TED were identified through LASSO. Immune cell infiltration analysis was performed using CIBERSORT.

RESULTS

Twenty-three immune-related DEmRNAs were revealed and were primarily enriched in humoral immune response, positive regulation of inflammatory response, IL-17, and TNF pathways. Co-expression regulatory network included four TFs and 16 immune-related DEmRNAs. Seven diagnostic genes were identified, with Area Under the Curve (AUC) of 0.993 for training set and AUC value of 0.836 for validation set. TED patients exhibited elevated infiltration levels by macrophages M2, mast cells, and CD8 T cells among 22 immune cell types, whereas macrophages M2 and mast cells resting were significantly lower than normal group.

CONCLUSIONS

The seven feature genes had high diagnostic value for TED patients. Our work explored regulatory network and diagnostic biomarkers, laying theoretical basis for TED diagnosis and treatment.

RelB-deficient autoinflammatory pathology presents as interferonopathy, but in mice is interferon-independent

BACKGROUND

Autoimmune diseases are leading causes of ill health and morbidity and have diverse etiology. Two signaling pathways are key drivers of autoimmune pathology, interferon and nuclear factor-κB (NF-κB)/RelA, defining the 2 broad labels of interferonopathies and relopathies. Prior work has established that genetic loss of function of the NF-κB subunit RelB leads to autoimmune and inflammatory pathology in mice and humans.

OBJECTIVE

We sought to characterize RelB-deficient autoimmunity by unbiased profiling of the responses of immune sentinel cells to stimulus and to determine the functional role of dysregulated gene programs in the RelB-deficient pathology.

METHODS

Transcriptomic profiling was performed on fibroblasts and dendritic cells derived from patients with RelB deficiency and knockout mice, and transcriptomic responses and pathology were assessed in mice deficient in both RelB and the type I interferon receptor.

RESULTS

We found that loss of RelB in patient-derived fibroblasts and mouse myeloid cells results in elevated induction of hundreds of interferon-stimulated genes. Removing hyperexpression of the interferon-stimulated gene program did not ameliorate the autoimmune pathology of RelB knockout mice. Instead, we found that RelB suppresses a different set of inflammatory response genes in a manner that is independent of interferon signaling but associated with NF-κB binding motifs.

CONCLUSION

Although transcriptomic profiling would describe RelB-deficient autoimmune disease as an interferonopathy, the genetic evidence indicates that the pathology in mice is interferon-independent.

NIH/3T3 Fibroblasts Selectively Activate T Cells Specific for Posttranslationally Modified Collagen Type II

It has been shown that synovial fibroblasts (SF) play a key role in the initiation of inflammation and joint destruction, leading to arthritis progression. Fibroblasts may express major histocompatibility complex class II region (MHCII) molecules, and thus, they could be able to process and present antigens to immunocompetent cells. Here we examine whether different types of fibroblasts (synovial, dermal, and thymic murine fibroblasts, destructive LS48 fibroblasts, and noninvasive NIH/3T3 fibroblasts) may be involved in the initiation of rheumatoid arthritis (RA) pathogenesis and can process and present type II collagen (COL2)-an autoantigen associated with RA. Using a panel of MHCII/Aq-restricted T-cell hybridoma lines that specifically recognize an immunodominant COL2 epitope (COL2_259-273), we found that NIH/3T3 fibroblasts activate several T-cell clones that recognize the posttranslationally glycosylated or hydroxylated COL2_259-273 epitope. The HCQ.3 hybridoma, which is specific for the glycosylated immunodominant COL2 epitope 259-273 (Gal264), showed the strongest response. Interestingly, NIH/3T3 cells, but not destructive LS48 fibroblasts, synovial, dermal, or thymic fibroblasts, were able to stimulate the HCQ.3 hybridoma and other COL2-specific T-cell hybridomas. Our experiments revealed that NIH/3T3 fibroblasts are able to activate COL2-specific T-cell hybridomas even in the absence of COL2 or a posttranslationally modified COL2 peptide. The mechanism of this unusual activation is contact-dependent and involves the T-cell receptor (TCR) complex.

Immune and Non-Immune Inflammatory Cells Involved in Autoimmune Fibrosis: New Discoveries

Fibrosis is an important health problem and its pathogenetic activation is still largely unknown. It can develop either spontaneously or, more frequently, as a consequence of various underlying diseases, such as chronic inflammatory autoimmune diseases. Fibrotic tissue is always characterized by mononuclear immune cells infiltration. The cytokine profile of these cells shows clear proinflammatory and profibrotic characteristics. Furthermore, the production of inflammatory mediators by non-immune cells, in response to several stimuli, can be involved in the fibrotic process. It is now established that defects in the abilities of non-immune cells to mediate immune regulation may be involved in the pathogenicity of a series of inflammatory diseases. The convergence of several, not yet well identified, factors results in the aberrant activation of non-immune cells, such as epithelial cells, endothelial cells, and fibroblasts, that, by producing pro-inflammatory molecules, exacerbate the inflammatory condition leading to the excessive and chaotic secretion of extracellular matrix proteins. However, the precise cellular mechanisms involved in this process have not yet been fully elucidated. In this review, we explore the latest discoveries on the mechanisms that initiate and perpetuate the vicious circle of abnormal communications between immune and non-immune cells, responsible for fibrotic evolution of inflammatory autoimmune diseases.

Single-cell computational machine learning approaches to immune-mediated inflammatory disease: New tools uncover novel fibroblast and macrophage interactions driving pathogenesis

Recent advances in single-cell sequencing technologies call for greater computational scalability and sensitivity to analytically decompose diseased tissues and expose meaningful biological relevance in individual cells with high resolution. And while fibroblasts, one of the most abundant cell types in tissues, were long thought to display relative homogeneity, recent analytical and technical advances in single-cell sequencing have exposed wide variation and sub-phenotypes of fibroblasts of potential and apparent clinical significance to inflammatory diseases. Alongside anticipated improvements in single cell spatial sequencing resolution, new computational biology techniques have formed the technical backbone when exploring fibroblast heterogeneity. More robust models are required, however. This review will summarize the key advancements in computational techniques that are being deployed to categorize fibroblast heterogeneity and their interaction with the myeloid compartments in specific biological and clinical contexts. First, typical machine-learning-aided methods such as dimensionality reduction, clustering, and trajectory inference, have exposed the role of fibroblast subpopulations in inflammatory disease pathologies. Second, these techniques, coupled with single-cell predicted computational methods have raised novel interactomes between fibroblasts and macrophages of potential clinical significance to many immune-mediated inflammatory diseases such as rheumatoid arthritis, ulcerative colitis, lupus, systemic sclerosis, and others. Third, recently developed scalable integrative methods have the potential to map cross-cell-type spatial interactions at the single-cell level while cross-tissue analysis with these models reveals shared biological mechanisms between disease contexts. Finally, these advanced computational omics approaches have the potential to be leveraged toward therapeutic strategies that target fibroblast-macrophage interactions in a wide variety of inflammatory diseases.

Optical coherence tomography and electrophysiological analysis of proptotic eyes due to thyroid-associated ophthalmopathy

Purpose

To study the degree of morphological and functional changes in thyroid-associated ophthalmology (TAO) patients using optical coherence tomography and electrophysiological studies and investigate their clinical correlation.

Methods

A cross-sectional study including 40 patients with TAO and a control group with age- and sex-matched healthy subjects. All subjects underwent a complete ophthalmological examination, proptosis evaluation, spectral domain optical coherence tomography, and electrophysiological tests (pattern and multifocal electroretinograms, and visual evoked potentials).

Results

On multiple regression analysis, the degree of proptosis and P50 amplitude were the most important predictors of central foveal thickness (CFT) (β =  −  0.56 and 0.39 and p = 0.03 and 0.01, respectively); while duration of the disease, and clinical activity score (CAS) were the most important predictors of average RNFL thickness (β = 0.67 and  − 0.81 and p = 0.004 and  <  0.001, respectively).

Conclusion

In the absence of fundus changes, macular thinning along with functional alterations noticed by pattern and multifocal electroretinogram could indicate presence of subclinical retinopathy in TAO cases.

Elevated expression of interleukin-27, IL-35, and decreased IL-12 in patients with thyroid-associated ophthalmopathy

PURPOSE

Thyroid-associated ophthalmopathy (TAO) is a chronic autoimmune disease. The interleukin-12 (IL-12) family includes IL-12, IL-23, IL-27, and IL-35, all of which play important roles in autoimmunity. Thus far, the relationship between IL-12, IL-27, and IL-35 and the TAO has not been evaluated.

METHODS

Seventy-five serum samples from patients with TAO were collected. Serum samples from 90 healthy controls (HC), 55 patients with Graves' disease (GD), 38 patients with uveitis (UV), 17 patients with Sjogren's syndrome (SS), and 65 patients with rheumatoid arthritis (RA) were collected as controls. The associations between IL-27, IL-35, IL-12, and other clinical parameters were analyzed.

RESULTS

Elevated serum levels of IL-27/IL-35 and decreased serum IL-12 levels were observed in TAO patients compared to those in HC (p < 0.001). For HC, we observed good diagnostic ability to predict TAO (area under the curve = 0.74, 0.78, and 0.78, for IL-27, IL-35, and IL-12, respectively). For other autoimmune diseases, IL-27, IL-35, and IL-12 had the ability to discriminate between UV, RA, and SS (area under the curve = 0.80, 0.83, and 0.85 for IL-27; 0.52, 0.69, and 0.67 for IL-35). The positive detection rates of IL-12 were significantly lower in the TAO group than in the UV and RA groups (p = 0.002, 0.01).

CONCLUSION

IL-12, IL-27, and IL-35 have the potential as biomarkers for TAO.

Different Effects of Cigarette Smoke, Heated Tobacco Product and E-Cigarette Vapour on Orbital Fibroblasts in Graves' Orbitopathy; a Study by Real Time Cell Electronic Sensing

Thyroid autoimmunity in Graves’ disease (GD) is accompanied by Graves’ orbitopathy (GO) in 40% of the cases. Orbital fibroblasts (OF) play a key role in the pathogenesis and cigarette smoking is a known deteriorating factor. Alongside conventional cigarettes (CC) new alternatives became available for smokers, including heated tobacco products (HTP) and E-cigarettes (ECIG). We aimed to study the cellular effects of smoke extracts (SE) in orbital fibroblasts. Primary OF cultures from GO and NON-GO orbits were exposed to different concentrations of SE (1%, 50%) and the changes were followed using Real Time Cell Electronic Sensing (RT-CES). Untreated GO and NON-GO cells had different maximum cell index (CI) values of 3.3 and 2.79 respectively (p < 0.0001). CC, HTP and ECIG treated NON-GO fibroblasts exhibited peak CIs of 2.62, 3.32 and 3.41 while treated GO cells’ CIs were higher, 5.38, 6.25 and 6.33, respectively (p < 0.0001). The metabolic activity (MTT) decreased (p < 0.001) and hyaluronan production doubled (p < 0.02) after 50% of CC SE treatment in all cell cultures. GO fibroblasts were more sensitive to low concentration SE then NON-GO fibroblasts (p < 0.0001). The studied SEs exerted different effects. RT-CES is a sensitive technique to detect the effects of very low concentration of SE on fibroblasts.

An Early Wave of Macrophage Infiltration Intertwined with Antigen-Specific Proinflammatory T Cells and Browning of Adipose Tissue Characterizes the Onset of Orbital Inflammation in a Mouse Model of Graves' Orbitopathy

Background: Graves' orbitopathy (GO) is an autoimmune-driven manifestation of Graves' disease (GD) where pathogenic autoantibodies to the thyrotropin receptor (TSHR) activate orbital fibroblasts/preadipocytes in the orbital tissue to induce inflammation and extracellular matrix deposition. Since there are significant limitations to study immunological and proinflammatory mediator expression in early and during disease progression in GO patients, we used our experimental mouse model to elucidate early pathogenic processes. Methods: We have developed a robust mouse model of GD/GO induced by electroporation immunization of plasmid encoding human TSHR A-subunit, comprising multiple injections over a course of 15 weeks to fully recapitulate the orbital pathology. In this study, we investigated kinetics of GO development in the model by serial analyses of immunological and cellular parameters during course of orbital inflammation. Results: Pathogenic anti-TSHR antibodies with thyroid-stimulating properties developed early after the second immunization step with concomitant induction of hyperthyroidism. Examination of orbital tissue showed an early wave of macrophage infiltration followed subsequently by CD3⁺ T cells into the orbital tissue. Examination of antigen-specific T cell activity using recombinant human A-subunit protein showed high CD8⁺ T cell proliferation during this early phase of disease onset, whereas effector CD4⁺ T cells and CD25⁺FOXP3⁺ regulatory T cells (Tregs) were downregulated. The early phase of disease was also characterized by abundant presence of proinflammatory cytokines interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α). Moreover, as the disease progressed, there was significant increase in browning of orbital fat tissue, which may be dependent on the proinflammatory milieu and/or the increased thyroid hormone levels during the established hyperthyroid status. Conclusions: This work revealed early infiltration of macrophages in the orbital region and induction of pathogenic anti-TSHR antibodies during disease onset in the model. This was followed subsequently by influx of CD8⁺ T cells specific for TSHR coupled with reduction in Tregs and substantial increase in brown adipose tissue. These new insights into the development of orbital inflammation in the model have implications for testing new therapeutic regimens by targeting macrophage function during early phases of orbital inflammation in the model.

Choroidal vascularity index in thyroid eye disease: comparison with controls and application in diagnosing non-inflammatory active disease

PURPOSE

To report the differences in choroidal vascularity index (CVI) in thyroid eye disease (TED) and normals and its discriminatory value for differentiating various stages of TED.

METHODS

Prospective, cross-sectional, non-interventional imaging study. Ninety-four eyes of 54 patients were included and divided into 5 groups - normal controls (C), inactive TED (I), active TED (A), non-inflammatory active TED (NIA) and systemic hyperthyroid disorder but no TED (SYS). Choroidal images were acquired using the swept-source optical coherence tomography and the choroid was binarized to calculate the CVI.

RESULTS

Ninety-four eyes were included. Mean age was 44.52 ± 10.02 years (median 46 years, range 19-65 years). Mean IOP was 16.1 ± 3.37 mm Hg (median 16 mm Hg, range 16-24 mm Hg). Mean Spherical equivalent (SE) was -0.08 ± 1.86 diopters (median 0, range -2.5 to +2.25). Intra-rater agreement was 0.84 (p < 0.001). Inter-rater agreement was noted to be 0.85 (p < 0.001) for consistency and 0.77 (p < 0.001) for absolute agreement. CVI in the A group was 70.11 ± 3.38% and in the NIA group was 69.32 ± 3.5%. Both were comparable to each other and significantly higher than the C, I and SYS groups (p < 0.001). Multiple regression showed that the Clinical Activity Score (CAS) had a positive effect and spheroequivalent had a negative effect on the CVI. At CVI of 66.83%, active TED can be diagnosed with sensitivity of 91.67% and specificity of 82.14%                 .

CONCLUSIONS

CVI is significantly higher in active TED and NIA TED compared to other groups. It has a good value in differentiating the non-inflammatory active TED eyes from the inactive eyes.

Choroidal Thickness in Thyroid Eye Disease: Comparison With Controls and Application in Diagnosing Non-Inflammatory Active Disease

Introduction

Choroidal thickness is known to vary in various systemic diseases. In the current study, we aim to report the differences in choroidal thickness in thyroid eye disease (TED) and normals and its discriminatory value for differentiating various stages of TED.

Methods

Prospective, cross-sectional, non-interventional imaging study. In an institutional practice, 102 eyes of 51 patients were included and divided into five groups: normal controls (C), inactive TED (I), active TED (A), non-inflammatory active TED (NIA) and systemic thyroid disorder but no TED (SYS). Choroidal images were acquired using the swept-source optical coherence tomography (Topcon DRI OCT Triton) with automatic layer segmentation which provided an automatic measurement of the subfoveal choroidal thickness and the mean in nine subfields based on the Early Treatment Diabetic Retinopathy Study (ETDRS) grid. One-way analysis of variance (ANOVA), Youden index and area under the receiver operating characteristic curves (AUROC) were reported.

Results

Central choroidal thickness in the A group was 279±37.52 microns and in the NIA group was 302.5±59.22 microns. Both were comparable to each other and significantly higher than the C, I and SYS groups (p<0.001). All ETDRS sub-fields showed significant AUROC to distinguish NIA from I. Most significant Youden index was for the inner nasal and central ETDRS subfields (0.55 and 0.61 respectively). Inner nasal sub-field showed 100% specificity while the central sub-field, showed 86.5% for predicting NIA. At a choroidal thickness of >266 microns, the central sub-field had the strongest discriminatory potential to predict NIA. 

Conclusion

Choroidal thickness is greater in active and non-inflammatory active TED. The inner nasal and central ETDRS sub-fields have value in differentiating the non-inflammatory active TED eyes from the inactive eyes.

Fibroblasts as confederates of the immune system

Fibroblastic stromal cells are as diverse, in origin and function, as the niches they fashion in the mammalian body. This cellular variety impacts the spectrum of responses elicited by the immune system. Fibroblast influence on the immune system keeps evolving our perspective on fibroblast roles and functions beyond just a passive structural part of organs. This review discusses the foundations of fibroblastic stromal-immune crosstalk, under the scope of stromal heterogeneity as a basis for tissue-specific tutoring of the immune system. Focusing on the skin as a relevant immunological organ, we detail the complex interactions between distinct fibroblast populations and immune cells that occur during homeostasis, injury repair, scarring, and disease. We further review the relevance of fibroblastic stromal cell heterogeneity and how this heterogeneity is central to regulate the immune system from its inception during embryonic development into adulthood.

Leptin receptor is a key gene involved in the immunopathogenesis of thyroid-associated ophthalmopathy

Thyroid‐associated ophthalmopathy (TAO), the most common and severe manifestation of Graves' disease (GD), is a disfiguring and potentially blinding autoimmune disease. The high relapse rate (up to 20%) and substantial side effects of glucocorticoid treatment further decrease the life quality of TAO patients. To develop novel therapies, we amid to explore the immunopathogenesis of TAO. To identify the key immune‐related genes (IRGs) in TAO, we integrated the IRG expression profiles in thyrocytes from a GD patient set (GD vs healthy control) and a TAO patient set (TAO vs GD). Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), protein‐protein interaction (PPI) and receiver operating characteristic (ROC) curve analyses identified the leptin receptor (LEPR) gene as the key IRG in TAO immunopathogenesis. Gene set enrichment analysis (GSEA) suggested enrichment of the antigen presentation pathway in TAO patients with higher LEPR. Increased LEPR expression was validated in TAO orbital tissues, and weighted gene co‐expression network analysis (WGCNA) showed that cell adhesion processes were positively correlated with LEPR. Our study revealed that LEPR is a key gene in TAO immunopathogenesis and plays different roles in thyrocytes and orbital tissues. Our findings provide new insights into diagnostic and therapeutic biomarkers for TAO.

JNK and p38 Inhibitors Prevent Transforming Growth Factor-β1-Induced Myofibroblast Transdifferentiation in Human Graves' Orbital Fibroblasts

Transforming growth factor-β1 (TGF-β1)-induced myofibroblast transdifferentiation from orbital fibroblasts is known to dominate tissue remodeling and fibrosis in Graves’ ophthalmopathy (GO). However, the signaling pathways through which TGF-β1 activates Graves’ orbital fibroblasts remain unclear. This study investigated the role of the mitogen-activated protein kinase (MAPK) pathway in TGF-β1-induced myofibroblast transdifferentiation in human Graves’ orbital fibroblasts. The MAPK pathway was assessed by measuring the phosphorylation of p38, c-Jun N-terminal kinase (JNK), and extracellular-signal-regulated kinase (ERK) by Western blots. The expression of connective tissue growth factor (CTGF), α-smooth muscle actin (α-SMA), and fibronectin representing fibrogenesis was estimated. The activities of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) responsible for extracellular matrix (ECM) metabolism were analyzed. Specific pharmacologic kinase inhibitors were used to confirm the involvement of the MAPK pathway. After treatment with TGF-β1, the phosphorylation levels of p38 and JNK, but not ERK, were increased. CTGF, α-SMA, and fibronectin, as well as TIMP-1 and TIMP-3, were upregulated, whereas the activities of MMP-2/-9 were inhibited. The effects of TGF-β1 on the expression of these factors were eliminated by p38 and JNK inhibitors. The results suggested that TGF-β1 could induce myofibroblast transdifferentiation in human Graves’ orbital fibroblasts through the p38 and JNK pathways.

Retinal vascularity, nerve fiber, and ganglion cell layer thickness in thyroid eye disease on optical coherence tomography angiography

Purpose: To compare the retinal vascularity, peripapillary vascularity, nerve fiber layer thickness and ganglion cell layer thickness between active, inactive thyroid eye disease (TED) and healthy eyes.Methods: Retrospective comparative cross-sectional cohort study. Patients with TED, active and inactive on the VISA score, and healthy eyes were included. All patients underwent optical coherence tomography angiography with detailed demographic and clinical data capture. Using automated software, retinal and peripapillary vascularity index, nerve fiber layer thickness, and ganglion cell layer thickness were calculated and were compared between the groups.Results: Twenty-four eyes with active TED, 102 eyes with inactive TED and 52 healthy eyes were included. Independent sample t test was used to compare parametric data and Mann-Whitney test to compare non-parametric data. The age and gender were comparable across groups. The peripapillary vascularity index (26.82 ± 4.13 versus 34.92 ± 5.08, p = .002) and the macular vascularity index (20.32 ± 2.5 versus 31.21 ± 3.89, p < .0001) were reduced in active TED eyes versus inactive eyes. Macular vascularity index was comparable in the inactive versus the healthy eyes. The RNFL thickness was increased in the active TED eyes versus the inactive eyes (45.11 ± 18.3 versus 35.55 ± 7, p = .03) and active versus healthy eyes (45.11 ± 18.3 versus 36.28 ± 7.89, p = .03). Ganglion cell layer thickness between all three groups was comparable.Conclusion: Decrease in peripapillary and macular vascular density and increase in RNFL thickness are seen in active TED compared to inactive TED and healthy eyes. In disease inactivity, these parameters are comparable to healthy eyes.

Integrating Differential Gene Expression Analysis with Perturbagen-Response Signatures May Identify Novel Therapies for Thyroid-Associated Orbitopathy

Purpose

To evaluate the efficacy of Library of Integrated Network-based Cellular Signatures (LINCS) perturbagen prediction software to identify small molecules that revert pathologic gene signature and alter disease phenotype in orbital adipose stem cells (OASCs) derived from patients with thyroid-associated orbitopathy (TAO).

Methods

Differentially expressed genes identified via RNA sequencing were inputted into LINCS L1000 Characteristic Direction Signature Search Engine (L1000CDS²) to predict candidate small molecules to reverse pathologic gene expression. TAO OASC cell lines were treated in vitro with six identified small molecules (Torin-2, PX12, withaferin A, isoliquiritigenin, mitoxantrone, and MLN8054), and expression of key adipogenic and differentially expressed genes was measured with quantitative polymerase chain reaction after 7 days of treatment. OASCs were differentiated into adipocytes, treated for 15 days, and stained with Oil Red O (OD 490 nm) to evaluate adipogenic changes.

Results

The expression of key differentially expressed genes (IRX1, HOXB2, S100B, and KCNA4) and adipogenic genes (peroxisome proliferator activated receptor-γ, FABP4) was significantly decreased in TAO OASCs after treatment (P < .05). In treated TAO adipocytes (n = 3), all six tested small molecules yielded significant decrease (P < .05) in Oil Red O staining. In treated non-TAO adipocytes (n = 3), only three of the drugs yielded a significant decrease in Oil Red O staining.

Conclusions

Combining disease expression signatures with LINCS small molecule prediction software can identify promising preclinical drug candidates for TAO.

Translational Relevance

These findings may offer insight into future potential therapeutic options for TAO and demonstrate a streamlined model to predict drug candidates for other diseases.

Integrative transcriptomics and proteomic analysis of extraocular muscles from patients with thyroid-associated ophthalmopathy

Our study aimed to reveal the underlying pathologic mechanisms of thyroid-associated ophthalmopathy (TAO) by integrative transcriptomics and proteomic analysis of extraocular muscles (EOM). The study involved 11 TAO patients (clinical activity score ≤ 2) and 11 control donors. Total RNA was extracted from EOM samples of 5 TAO patients and 5 control individuals for gene microarray analysis to reveal differentially expressed genes. Concurrently, EOM samples from 3 TAO patients and 3 control individuals were lysed for quantitative proteomic analysis. Differentially expressed genes and proteins were identified, followed by functional and pathway enrichment analysis and protein-protein interaction network construction. Concordance between proteins and transcripts was examined, and functional annotations were conducted. Expressions of versican (VCAN) and lipocalin 1 (LCN1) in EOM samples from another 3 TAO patients and 3 control individuals were measured by western blotting. In total, 952 genes and 137 proteins were identified as differentially expressed, as well as 96 differentially expressed proteins without significantly changed mRNA abundance. Proteins mainly related to the composition (such as MYH1, MYH2, and MYH13) and contraction force (MYH3, MYH8, ACTN3, and TNNT1) of the muscle fibers were significantly up-regulated in EOM samples of TAO, as well as those (such as VCAN, MPZ, and PTPRC) associated with cell adhesion. In addition, differentially expressed proteins related to the components and metabolism of extracellular matrix (ECM) (such as COL1A1, COL1A2, COL2A1, VCAN, OGN, and DCN) were identified. Similarly, expressions of genes involved in cell adhesion and ECM metabolism were significantly different between EOM samples of TAO patients and controls. Western blotting verified that VCAN involved in ECM proteoglycans and diseases associated with glycosaminoglycan metabolism was markedly higher in EOM samples of TAO, whereas LCN1 was obviously decreased. In conclusion, this study demonstrated the significantly altered cellular components of EOM, muscle contraction, cell adhesion and ECM metabolism, which might be involved in the pathologic mechanisms and/or consequences of TAO.

Fibrosis in dysthyroid eye disease

Dysthyroid eye disease is a rare condition, mainly found in people with Graves' hyperthyroidism. Autoimmune responses to thyroid/orbit shared antigens drive extensive tissue remodelling. This includes excess adipogenesis and over-production of extra-cellular matrix, which both tend to occur in the earlier 'active' inflammatory stages of disease. With time these give way to fibrosis, which has a profound impact on eye motility and may be life-long. Progress has been made in identifying the shared autoantigen(s) and the role of specific T cells and autoantibodies in remodelling, which have facilitated development of novel therapies. However relatively little is known of the autoimmune processes under-pinning fibrosis and currently there are no adequate medical treatments.

New insights into the pathogenesis and nonsurgical management of Graves orbitopathy

Graves orbitopathy, also known as thyroid eye disease or thyroid-associated orbitopathy, is visually disabling, cosmetically disfiguring and has a substantial negative impact on a patient's quality of life. There is increasing awareness of the need for early diagnosis and rapid specialist input from endocrinologists and ophthalmologists. Glucocorticoids are the mainstay of treatment; however, recurrence occurs frequently once these are withdrawn. Furthermore, in >60% of cases, normal orbital anatomy is not restored, and skilled rehabilitative surgery is required. Clinical trials have shown that considerable benefit can be derived from the addition of antiproliferative agents (such as mycophenolate or azathioprine) in preventing deterioration after steroid cessation. In addition, targeted biologic therapies have shown promise, including teprotumumab, which reduces proptosis, rituximab (anti-CD20), which reduces inflammation, and tocilizumab, which potentially benefits both of these parameters. Other strategies such as orbital radiotherapy have had their widespread role in combination therapy called into question. The pathophysiology of Graves orbitopathy has also been revised with identification of new potential therapeutic targets. In this Review we provide an up-to-date overview of the field, outline the optimal management of Graves orbitopathy and summarize the research developments in this area to highlight future research questions and direct future clinical trials.

Relation Between Immunohistochemical Expression of Hippo Pathway Effectors and Chronic Hepatitis Induced Fibrosis in Egyptian Patients

OBJECTIVE

Chronic hepatitis is a global health problem especially in Egypt. Hepatic fibrosis is a common end clinical manifestation of many chronic liver diseases. Although it is a wound-healing process, excessive accumulation of fibrillary collagen leads to architectural damage, cirrhosis and liver failure. Recently, a few studies have linked Hippo pathway effectors of yes-associated protein (YAP) and its paralog transcriptional coactivator with PDZ-binding motif (TAZ) to extracellular matrix deposition and ongoing fibrosis.

MATERIAL AND METHOD

Immunohistochemical expression of YAP and TAZ were analyzed in 121 liver needle core biopsies (91 core biopsies of chronic viral hepatitis, 20 biopsies of autoimmune hepatitis and 10 normal liver cores).

RESULTS

YAP and TAZ nuclear localization was absent in all normal liver cores. Autoimmune hepatitis cases showed higher nuclear expression of both YAP and TAZ in comparison to chronic viral cases. YAP and TAZ expression were correlated with severity of hepatocyte injury together with fibrosis in chronic viral cases but these correlations were absent in AIH cases despite the pronounced increase of YAP and TAZ nuclear localization.

CONCLUSION

The correlation between Hippo effectors activation and fibrosis in chronic viral hepatitis patients emphasize their role in the development and advancement of hepatic scarring and highlight the use of both YAP and TAZ as novel targets to ameliorate liver fibrosis.

Graphene Oxide in a Composite with Silver Nanoparticles Reduces the Fibroblast and Endothelial Cell Cytotoxicity of an Antibacterial Nanoplatform

Antibacterial surfaces coated with nanomaterials, including silver nanoparticles, are considered effective alternative antimicrobial agents that can be used instead of antibiotics and chemical agents. However, reports of the potential toxicity of these materials raise questions about the safety of their use in biomedical applications. The objective of this research was to reduce the human cell cytotoxicity of silver nanoparticle-coated polyurethane foils by complexing silver nanoparticles with graphene oxide. The antimicrobial activity of nanoplatforms coated with silver nanoparticles, graphene oxide and the composite of silver nanoparticles and graphene oxide was assessed with Salmonella enteritidis. Cytotoxicity was analysed by an analysis of the viability and morphology of human fibroblasts, human umbilical vein endothelial cells (HUVECs) and chicken embryo chorioallantoic membrane. Additionally, the synthesis level of inflammatory proteins was examined for fibroblasts cultured on different nanoplatforms. The nanoplatform coated with the silver nanoparticles and graphene oxide composite showed strongest antibacterial properties, although nanoplatforms coated with only silver nanoparticles or graphene oxide also resulted in decreased S. enteritidis growth. Furthermore, a nanoplatform coated with silver nanoparticles and graphene oxide composite showed limited immunological stimulation and significantly reduced cytotoxicity towards fibroblasts, HUVECs and chicken embryo chorioallantoic membrane in comparison to the nanoplatform coated only with silver nanoparticles, due to the higher stability of the nanomaterials in the nanocomposite.

Quantitative Trait Loci Mapping for Lameness Associated Phenotypes in Holstein-Friesian Dairy Cattle

Lameness represents a significant challenge for the dairy cattle industry, resulting in economic losses and reduced animal health and welfare. The existence of underlying genomic variation for lameness associated traits has the potential to improve selection strategies by using genomic markers. Therefore, the aim of this study was to identify genomic regions and potential candidate genes associated with lameness traits. Lameness related lesions and digital cushion thickness were studied using records collected by our research team, farm records, and a combination of both. Genome-wide analyses were performed to identify significant genomic effects, and a combination of single SNP association analysis and regional heritability mapping was used to identify associated genomic regions. Significant genomic effects were identified for several lameness related traits: Two genomic regions were identified on chromosome 3 associated with digital dermatitis and interdigital hyperplasia, one genomic region on chromosome 23 associated with interdigital hyperplasia, and one genomic region on chromosome 2 associated with sole haemorrhage. Candidate genes in those regions are mainly related to immune response and fibroblast proliferation. Quantitative trait loci (QTL) identified in this study could enlighten the understanding of lameness pathogenesis, providing an opportunity to improve health and welfare in dairy cattle with the addition of these regions into selection programs.

The role of cell mediated immunopathogenesis in thyroid-associated ophthalmopathy

Currently, thyroid-associated ophthalmopathy (TAO) lacks effective treatment due to our lack of clarity in its immunopathogenesis. Orbital fibroblasts play a key role in altering inflammation and immune response in TAO, and are considered as the key target and effector cells in its pathogenesis. The orbit infiltrating CD34+ fibrocytes add on to the process by expressing high levels of autoantigens and inflammatory cytokines, while also differentiating into myofibroblasts or adipocytes. This review focuses on the role of orbital fibroblasts and CD34+ fibrocytes in the pathogenesis of TAO, highlighting the basis of emerging treatments.

Metformin and Autoimmunity: A "New Deal" of an Old Drug

Metformin (dimethyl biguanide) is a synthetic derivative of guanidine, isolated from the extracts of Galega officinalis, a plant with a prominent antidiabetic effect. Since its discovery more than 50 years ago, metformin represents a worldwide milestone in treatment of patients with type 2 diabetes (T2D). Recent evidence in humans indicates novel pleiotropic actions of metformin which span from its consolidated role in T2D management up to various regulatory properties, including cardio- and nephro-protection, as well as antiproliferative, antifibrotic, and antioxidant effects. These findings, together with ground-breaking studies demonstrating its ability to prolong healthspan and lifespan in mice, provided the basis for defining metformin as a potential antiaging molecule. Moreover, emerging in vivo and in vitro evidence support the novel hypothesis that metformin can exhibit immune-modulatory features. Studies suggest that metformin interferes with key immunopathological mechanisms involved in systemic autoimmune diseases, such as the T helper 17/regulatory T cell balance, germinal centers formation, autoantibodies production, macrophage polarization, cytokine synthesis, neutrophil extracellular traps release, and bone or extracellular matrix remodeling. These effects may represent a powerful contributor to antiaging and anticancer properties exerted by metformin and, from another standpoint, may open the way to assess whether metformin can be a candidate molecule for clinical trials involving patients with immune-mediated diseases. In this article, we will review the available preclinical and clinical evidence regarding the effect of metformin on individual cells of the immune system, with emphasis on immunological mechanisms related to the development and maintenance of autoimmunity and its potential relevance in treatment of autoimmune diseases.

Essential role of connective tissue growth factor (CTGF) in transforming growth factor-β1 (TGF-β1)-induced myofibroblast transdifferentiation from Graves' orbital fibroblasts

Connective tissue growth factor (CTGF) associated with transforming growth factor-β (TGF-β) play a pivotal role in the pathophysiology of many fibrotic disorders. However, it is not clear whether this interaction also takes place in GO. In this study, we investigated the role of CTGF in TGF-β-induced extracellular matrix production and myofibroblast transdifferentiation in Graves’ orbital fibroblasts. By Western blot analysis, we demonstrated that TGF-β1 induced the expression of CTGF, fibronectin, and alpha-smooth muscle actin (α-SMA) in Graves’ orbital fibroblasts. In addition, the protein levels of fibronectin and α-SMA in Graves’ orbital fibroblasts were also increased after treatment with a recombinant human protein CTGF (rhCTGF). Moreover, we transfected the orbital fibroblasts with a small hairpin RNA of CTGF gene (shCTGF) to knockdown the expression levels of CTGF, which showed that knockdown of CTGF significantly diminished TGF-β1-induced expression of CTGF, fibronectin and α-SMA proteins in Graves’ orbital fibroblasts. Furthermore, the addition of rhCTGF to the shCTGF-transfected orbital fibroblasts could restore TGF-β1-induced expression of fibronectin and α-SMA proteins. Our findings demonstrate that CTGF is an essential downstream mediator for TGF-β1-induced extracellular matrix production and myofibroblast transdifferentiation in Graves’ orbital fibroblasts and thus may provide with a potential therapeutic target for treatment of GO.

Transcriptome Analysis of Orbital Adipose Tissue in Active Thyroid Eye Disease Using Next Generation RNA Sequencing Technology

Objective:

This study utilized Next Generation Sequencing (NGS) to identify differentially expressed transcripts in orbital adipose tissue from patients with active Thyroid Eye Disease (TED) versus healthy controls.

Method:

This prospective, case-control study enrolled three patients with severe, active thyroid eye disease undergoing orbital decompression, and three healthy controls undergoing routine eyelid surgery with removal of orbital fat. RNA Sequencing (RNA-Seq) was performed on freshly obtained orbital adipose tissue from study patients to analyze the transcriptome. Bioinformatics analysis was performed to determine pathways and processes enriched for the differential expression profile. Quantitative Reverse Transcriptase-Polymerase Chain Reaction (qRT-PCR) was performed to validate the differential expression of selected genes identified by RNA-Seq.

Results:

RNA-Seq identified 328 differentially expressed genes associated with active thyroid eye disease, many of which were responsible for mediating inflammation, cytokine signaling, adipogenesis, IGF-1 signaling, and glycosaminoglycan binding. The IL-5 and chemokine signaling pathways were highly enriched, and very-low-density-lipoprotein receptor activity and statin medications were implicated as having a potential role in TED.

Conclusion:

This study is the first to use RNA-Seq technology to elucidate differential gene expression associated with active, severe TED. This study suggests a transcriptional basis for the role of statins in modulating differentially expressed genes that mediate the pathogenesis of thyroid eye disease. Furthermore, the identification of genes with altered levels of expression in active, severe TED may inform the molecular pathways central to this clinical phenotype and guide the development of novel therapeutic agents.

Salicylate-based phytopharmaceuticals induce adaptive cytokine and chemokine network responses in human fibroblast cultures

BACKGROUND

Cytokines and chemokines (CC) play a central role in immunoregulatory and inflammatory processes. Neutralising antibodies for single proinflammatory cytokines have developed into a powerful, though expensive and not always curative therapeutic strategy for severe diseases. Considering the redundancy of CC functions, network (N) rather than single target approaches are essential. Phytopharmaceuticals, common adjuvant therapies, are known modulators of a broad spectrum of CCs, but as complex mixtures with multiple targets they have not been systematically investigated. We investigated the effect of clinically established salicylate-based phytopharmaceuticals alone or in combination on CCNs under non-inflammatory and inflammatory conditions, using fibroblasts being a major source of cytokines in connective tissue diseases.

METHODS

Synchronised human skin fibroblasts (HSKF) were treated for 6 h with standardised fluid plant extracts (E) of Populus tremula L. [end concentration: 0.06%, 0.1%], Solidago virgaurea L. [0.02%, 0.1%], Fraxinus excelsior L. [0.02%, 0.1%], an established combination of the three extracts-STW1 [0.05, 0.1%] and acetyl salicylic acid (ASA) [30 µg/ml], individually or in the presence of lipopolysaccharides (LPS) [10 µg/ml]. Cell lysates were profiled for 23 cytokines. Supernatants were investigated for IL-6 and IL-8 release (ELISA). Total RNA was isolated for gene-expression profiling.

RESULTS

Under non-inflammatory conditions P. tremula E and ASA increased cellular proteins (P) IL-8 and IL-10; S. virgaurea E modulated IL-1α, IL-10, IL-15 and Groα (P). F. excelsior decreased IL-1α and IL-15 (P). The combination of the three extracts (STW1) modulated IL-1α, IL-3 and TNF-ß (P). LPS stimulation increased cellular IL-8, Groα, MCP-1 and RANTES (P) and increased the secretion of IL-6 and IL-8 into the medium. Under these inflammatory conditions F. excelsior reduced GMCSF, GCSF and RANTES. STW1 reduced IL-1α, IL-8, Groα, and MCP-1(P). Secretion of IL-8 and IL-6 was reduced by STW1 and ASA. Gene expression profiles supported non-additive CCN profiles.

CONCLUSION

Salicylate based phytopharmaceuticals provoke cellular pro-and anti-inflammatory CCN responses under non-stress conditions, which adapt to anti-inflammatory responses after LPS-stimulation. CCN-profiles of the single extracts are not additives in combination. A simultaneous activation of cellular pro- and anti-inflammatory cytokines might heighten the immunological reactivity status of a cell.

Optic Disc, Macula, and Retinal Nerve Fiber Layer Measurements Obtained by OCT in Thyroid-Associated Ophthalmopathy

Aim. To compare the measurements of retinal nerve fiber layer (RNFL), macula and optic disc parameters obtained by optical coherence tomography (OCT), and intraocular pressure (IOP) between the patients with thyroid-associated ophthalmopathy (TAO) and healthy controls. Methods. One hundred and thirty-two eyes of 66 patients with TAO and 72 eyes of 36 healthy controls were included in the study. Proptosis level was determined by Hertel exophthalmometer. Optic disc, peripapillary retinal nerve fiber layer, and macula parameters were measured by OCT. All measurements of the patients were compared with those of age- and sex-matched healthy controls. Results. No statistically significant difference was found between the patients with TAO and control group in terms of demographic characteristics (P > 0.05). Exophthalmometer measurements and IOP were higher in TAO group (P < 0.05). Mean macula thicknesses in TAO and control groups were 239.3 ± 29.8 μm and 246.6 ± 31.8 μm, respectively, and the difference between the groups was statistically significant (P = 0.000). TAO group had thinner inferior RNFL thickness and macular thicknesses (superior, inferior, temporal, and nasal) and higher disc area and C/D ratio when compared with the control group (P < 0.05). Conclusion. IOP, disc area, and C/D area ratio were higher in the patients with TAO and the thicknesses of macula and inferior RNFL were thinner when compared with healthy controls. This trial is registered with registration number at clinicaltrials.gov NCT02766660.

Cell density-dependent stimulation of PAI-1 and hyaluronan synthesis by TGF-β in orbital fibroblasts

During the course of Graves' orbitopathy (GO), orbital fibroblasts are exposed to factors that lead to proliferation and extracellular matrix (ECM) overproduction. Increased levels of tissue plasminogen activator inhibitor type 1 (PAI-1 (SERPINE1)) might promote the accumulation of ECM components. PAI-1 expression is regulated by cell density and various cytokines and growth factors including transforming growth factorβ(TGF-β). We examined the effects of increasing cell densities and TGF-β on orbital fibroblasts obtained from GO patients and controls. Responses were evaluated by the measurement of proliferation, PAI-1 expression, and ECM production. There was an inverse correlation between cell density and the per cell production of PAI-1. GO orbital, normal orbital, and dermal fibroblasts behaved similarly in this respect. Proliferation rate also declined with increasing cell densities. Hyaluronan (HA) production was constant throughout the cell densities tested in all cell lines. In both GO and normal orbital fibroblasts, but not in dermal fibroblasts, TGF-β stimulated PAI-1 production in a cell density-dependent manner, reaching up to a five-fold increase above baseline. This has been accompanied by increased HA secretion and pericellular HA levels at high cell densities. Increasing cell density is a negative regulator of proliferation and PAI-1 secretion both in normal and GO orbital fibroblasts; these negative regulatory effects are partially reversed in the presence of TGF-β. Cell density-dependent regulation of PAI-1 expression in the orbit, together with the local cytokine environment, may have a regulatory role in the turnover of the orbital ECM and may contribute to the expansion of orbital soft tissue in GO.

Alteration of Connective Tissue Growth Factor (CTGF) Expression in Orbital Fibroblasts from Patients with Graves' Ophthalmopathy

Graves’ ophthalmopathy (GO) is a disfiguring and sometimes blinding disease, which is characterized by inflammation and swelling of orbital tissues, with fibrosis and adipogenesis being predominant features. The aim of this study is to investigate whether the expression levels of fibrosis-related genes, especially that of connective tissue growth factor (CTGF), are altered in orbital fibroblasts of patients with GO. The role of oxidative stress in the regulation of CTGF expression in GO orbital fibroblasts is also examined. By a SYBR Green-based real time quantitative PCR (RT-QPCR), we demonstrated that the mRNA expression levels of fibronectin, apolipoprotein J, and CTGF in cultured orbital fibroblasts from patients with GO were significantly higher than those of age-matched normal controls (p = 0.007, 0.037, and 0.002, respectively). In addition, the protein expression levels of fibronectin, apolipoprotein J, and CTGF analyzed by Western blot were also significantly higher in GO orbital fibroblasts (p = 0.046, 0.032, and 0.008, respectively) as compared with the control. Furthermore, after treatment of orbital fibroblasts with a sub-lethal dose of hydrogen peroxide (200 μM H₂O₂), we found that the H₂O₂-induced increase of CTGF expression was more pronounced in the GO orbital fibroblasts as compared with those in normal controls (20% vs. 7%, p = 0.007). Importantly, pre-incubation with antioxidants including N-acetylcysteine (NAC) and vitamin C, respectively, resulted in significant attenuation of the induction of CTGF in GO orbital fibroblasts in response to H₂O₂ (p = 0.004 and 0.015, respectively). Taken together, we suggest that oxidative stress plays a role in the alteration of the expression of CTGF in GO orbital fibroblasts that may contribute to the pathogenesis and progression of GO. Antioxidants may be used in combination with the therapeutic agents for effective treatment of GO.

Liver myofibroblasts from hepatitis B related liver failure patients may regulate natural killer cell function via PGE2

BACKGROUND

Natural killer (NK) cells are abundant in the liver and constitute a major innate immune component that contributes to immune-mediated liver injury. However, few studies have investigated the phenotypes and functions of NK cells involved in hepatitis B related liver failure (LF), and the precise mechanism underlying NK cell regulation is not fully understood.

METHODS

We detected the percentage and function of peripheral NK cells both in hepatitis B related LF patients and healthy volunteers by flow cytometry and isolated the liver myofibroblasts (LMFs) from hepatitis B related LF livers. To determine the possible effects of LMFs on NK cells, mixed cell cultures were established in vitro.

RESULTS

We found a down-regulated percentage of peripheral NK cells in hepatitis B related LF patients, and their NK cells also displayed decreased activated natural cytotoxicity receptors (NCRs) and cytokine production. In a co-culture model, LMFs sharply attenuated IL-2-induced NK cell triggering receptors, cytotoxicity, and cytokine production. The inhibitory effect of LMFs on NK cells correlated with their ability to produce prostaglandin (PG) E2.

CONCLUSION

These data suggest that LMFs may protect against immune-mediated liver injury in hepatitis B related LF patients by inhibiting NK cell function via PGE2.

Cyclic compressive loading on 3D tissue of human synovial fibroblasts upregulates prostaglandin E2 via COX-2 production without IL-1β and TNF-α

Objective

Excessive mechanical stress on synovial joints causes osteoarthritis (OA) and results in the production of prostaglandin E2 (PGE2), a key molecule in arthritis, by synovial fibroblasts. However, the relationship between arthritis-related molecules and mechanical stress is still unclear. The purpose of this study was to examine the synovial fibroblast response to cyclic mechanical stress using an in vitro osteoarthritis model.

Method

Human synovial fibroblasts were cultured on collagen scaffolds to produce three-dimensional constructs. A cyclic compressive loading of 40 kPa at 0.5 Hz was applied to the constructs, with or without the administration of a cyclooxygenase-2 (COX-2) selective inhibitor or dexamethasone, and then the concentrations of PGE2, interleukin-1β (IL-1β), tumour necrosis factor-α (TNF-α), IL-6, IL-8 and COX-2 were measured.

Results

The concentrations of PGE2, IL-6 and IL-8 in the loaded samples were significantly higher than those of unloaded samples; however, the concentrations of IL-1β and TNF-α were the same as the unloaded samples. After the administration of a COX-2 selective inhibitor, the increased concentration of PGE2 by cyclic compressive loading was impeded, but the concentrations of IL-6 and IL-8 remained high. With dexamethasone, upregulation of PGE2, IL-6 and IL-8 was suppressed.

Conclusion

These results could be useful in revealing the molecular mechanism of mechanical stress in vivo for a better understanding of the pathology and therapy of OA.

Cite this article: Bone Joint Res 2014;3:280–8.

Current concepts in the molecular pathogenesis of thyroid-associated ophthalmopathy

Graves' disease (GD) is a common autoimmune condition. At its core, stimulatory autoantibodies are directed at the thyroid-stimulating hormone receptor (TSHR), resulting in dysregulated thyroid gland activity and growth. Closely associated with GD is the ocular condition known as thyroid-associated ophthalmopathy (TAO). The pathogenesis of TAO remains enigmatic as do the connections between the thyroid and orbit. This review highlights the putative molecular mechanisms involved in TAO and suggests how these insights provide future directions for identifying therapeutic targets. Genetic, epigenetic, and environmental factors have been suggested as contributory to the development of GD and TAO. Thyroid-stimulating hormone receptor and insulin-like growth factor receptor (IGF-1R) are expressed at higher levels in the orbital connective tissue from individuals with TAO than in healthy tissues. Together, they form a functional complex and appear to promote signaling relevant to GD and TAO. Orbital fibroblasts display an array of cell surface receptors and generate a host of inflammatory molecules that may participate in T and B cell infiltration. Recently, a population of orbital fibroblasts has been putatively traced to bone marrow-derived progenitor cells, known as fibrocytes, as they express CD45, CD34, CXCR4, collagen I, functional TSHR, and thyroglobulin (Tg). Fibrocytes become more numerous in GD and we believe traffic to the orbit in TAO. Numerous attempts at developing complete animal models of GD have been largely unsuccessful, because they lack fidelity with the ocular manifestations seen in TAO. Better understanding of the pathogenesis of TAO and development of improved animal models should greatly accelerate the identification of medical therapy for this vexing medical problem.

Dysregulated proinflammatory and fibrogenic phenotype of fibroblasts in cystic fibrosis

Morbi-mortality in cystic fibrosis (CF) is mainly related to chronic lung infection and inflammation, uncontrolled tissue rearrangements and fibrosis, and yet the underlying mechanisms remain largely unknown. We evaluated inflammatory and fibrosis responses to bleomycin in F508del homozygous and wild-type mice, and phenotype of fibroblasts explanted from mouse lungs and skin. The effect of vardenafil, a cGMP-specific phosphodiesterase type 5 inhibitor, was tested in vivo and in culture. Responses of proinflammatory and fibrotic markers to bleomycin were enhanced in lungs and skin of CF mice and were prevented by treatment with vardenafil. Purified lung and skin fibroblasts from CF mice proliferated and differentiated into myofibroblasts more prominently and displayed higher sensitivity to growth factors than those recovered from wild-type littermates. Under inflammatory stimulation, mRNA and protein expression of proinflammatory mediators were higher in CF than in wild-type fibroblasts, in which CFTR expression reached similar levels to those observed in other non-epithelial cells, such as macrophages. Increased proinflammatory responses in CF fibroblasts were reduced by half with submicromolar concentrations of vardenafil. Proinflammatory and fibrogenic functions of fibroblasts are upregulated in CF and are reduced by vardenafil. This study provides compelling new support for targeting cGMP signaling pathway in CF pharmacotherapy.

Extracellular matrix proteins and displacement of cultured fibroblasts from duodenal biopsies in celiac patients and controls

BACKGROUND

Celiac disease (CD) is mainly characterised by villous atrophy and mucosal architectural rearrangement. The fibroblasts (FBs) are the most abundant mesenchymal cell type in the intestinal mucosa and are responsible for both the architectural arrangement of the villi and the formation of the extracellular matrix (ECM). This study aimed at the evaluation of both the intracellular distribution of different proteins involved in ECM and FBs characterisation, and the cellular displacement of primary FBs obtained from duodenal endoscopic biopsies of healthy subjects and celiac patients.

METHODS

Primary healthy and celiac duodenal FBs were evaluated by means of immuno-fluorescence assay for collagen type I and IV, fibronectin, actin, alpha-Smooth Muscle Actin (alpha-SMA), Fibroblast Surface Protein (FSP) and transglutaminase type 2 (TG2). The geometric indexes of the fluorescence signals were investigated by image analysis software (Image J, NIH). Both morphology and kinetic were evaluated during a 72 hours time course movie. TG2 medium activity was evaluated by means of ELISA.

RESULTS

All the cells examined were immunopositive for FSP, alpha-SMA, actin, collagen I, collagen IV and TG2. CD cells showed a signet collagen-I and collagen-IV pattern, as compared to the controls being characterised by a spindle geometry. Moreover, the collagen signals in CD FBs showed a significantly higher circularity index (major orthogonal diameter ratio) than the controls (p<0.0001), whereas the perimeter and area ratio were significantly lower (p<0.0001). The TG2 signal had a decreased area (p<0.05), but a two-fold increased medium activity. The time course highlighted a reduction of the displacement of CD FBs.

CONCLUSIONS

The isolated primary CD FBs showed a different collagen and TG2 pattern of distribution associated with a different cellular displacement. The reasons for such CD cell peculiar characteristics are yet unknown but they might represent a factor in the progression of the intestinal damage.

Association of IL12B polymorphisms with susceptibility to Graves ophthalmopathy in a Taiwan Chinese population

Background

Interleukin 12B (IL12B) gene polymorphisms have been linked to several inflammatory diseases, but their role in the development of Graves ophthalmopathy (GO) in Graves disease (GD) patients is unclear. The purpose of this study was to investigate the disease association of IL12B single nucleotide polymorphisms (SNPs).

Methods

A Taiwan Chinese population comprising 200 GD patients with GO and 271 GD patients without GO was genotyped using an allele-specific extension and ligation method. Hardy-Weinberg equilibrium was estimated using the chi-square test. Allele and genotype frequencies were compared between GD patients with and without GO using the chi-square test.

Results

The genotype and allele frequencies of examined SNPs did not differ between GD patients with and without GO. Although the genotype distribution remained nonsignificant in the sex-stratified analyses, the frequency of the T allele at SNP rs1003199 was significantly higher in patients with GO in the male cohort (P = 6.00 × 10^-3). In addition, haplotypes of IL12B may be used to predict the risk of GO (P = 1.70 × 10^-2); however, we could not prove the statistical significance of analysis after applying the Bonferroni correction.

Conclusions

Our results provide new information that the examined IL12B gene polymorphisms may be associated with susceptibility to GO in the Taiwan Chinese population in a sex-specific manner. This conclusion requires further investigation.

Graves' orbitopathy: extraocular muscle/total orbit area ratio is positively related to the Clinical Activity Score

BACKGROUND AND OBJECTIVE

Both extraocular muscle (EOM) and orbital fat are involved in Graves' orbitopathy (GO) but their enlargement might occur with a different temporal pattern. Two GO subtypes have been described, one with predominant EOM enlargement and the other with prevalent fat tissue involvement. We longitudinally investigated the EOM in patients with GO and their relationship with clinical activity.

PATIENTS AND METHODS

By using commercial software with a segmentation technique, we calculated from computed tomography (CT) scan EOM coronal area (CA) and total orbit coronal area (TOA) in 23 control subjects and in 32 patients with GO. The latter were studied both at presentation and 18 months later. Superior, lateral, inferior, and medial EOM areas and TOA were selected by 3 different contiguous CT slices: A, B, and C, chosen at globe pole tangent and 2 and 4 mm backward. The Clinical Activity Score (CAS) was also measured.

RESULTS

Orbital EOM CA/TOA ratio (OM/TOA ratio) after 18 months decreased in most patients with GO, indicating that EOM area decrement contributed significantly to OM/TOA ratio reduction. Clinical Activity Score decrease was significantly correlated to the OM/TOA ratio decrease.

CONCLUSIONS

An easy method to measure CA of EOM and orbit allowed us to observe that in most patients with GO the OM/TOA ratio decreases with time, suggesting that macroscopic EOM involvement occurs initially and resolves as the other clinical signs and symptoms of the disease resolve, as indicated by the significant OM/TOA ratio correlation with CAS.

Fibroblasts expressing the thyrotropin receptor overarch thyroid and orbit in Graves' disease

CONTEXT

Graves' disease (GD) is a systemic autoimmune syndrome comprising manifestations in thyroid and orbital connective tissue. The link between these two tissues in GD eludes our understanding. Patients with GD have increased frequency of circulating monocyte lineage cells known as fibrocytes. These fibrocytes infiltrate orbital connective tissues in thyroid-associated ophthalmopathy and express functional TSH receptor (TSHR).

OBJECTIVE

The aim of the study was to identify and characterize CD34(+) fibrocytes in thyroid tissue.

DESIGN/SETTING/PARTICIPANTS

Patients undergoing surgical thyroidectomy at two academic medical centers were recruited to the study.

MAIN OUTCOME MEASURES

We performed immunohistochemistry, flow cytometry, real-time PCR, cytokine-specific ELISA, and cell differentiation.

RESULTS

CD34(+)ColI(+)CXCR4(+)TSHR(+) cells can be identified in situ in thyroid tissue from donors with GD, Hashimoto's thyroiditis, or in normal-appearing tissue. Thyroid fibroblasts cultivated from these glands express a CD34(-)ColI(+)CXCR4(+)TSHR(+) phenotype. TSHR levels are higher than those in orbital fibroblasts. When treated with TSH, thyroid fibroblasts generate IL-6 and IL-8. The induction of IL-6 can be blocked by dexamethasone, a chemical inhibitor of Akt/Pkb, and by knocking down Akt with a specific small interfering RNA. When treated with TGF-β or rosiglitazone, thyroid fibroblasts differentiate into myofibrocytes or adipocytes, respectively.

CONCLUSIONS

ColI(+)CXCR4(+)TSHR(+) thyroid fibroblasts resemble orbital fibroblasts and circulating fibrocytes. CD34(+) fibrocytes appear to infiltrate both tissues in GD. Thyroid fibroblasts lose CD34 display in culture, unlike orbital fibroblasts and circulating fibrocytes. Fibrocytes and their fibroblast derivatives may participate in the pathogenesis of thyroid autoimmunity after TSHR activation. They could represent a therapeutic target for these diseases.

Increased response to oxidative stress challenge in Graves' ophthalmopathy orbital fibroblasts

PURPOSE

To investigate whether orbital fibroblasts from patients with Graves' ophthalmopathy (GO) are more responsive to oxidative stress.

METHODS

Lipid peroxidation, oxidative DNA damage, reactive oxygen species (ROS) contents and activities of antioxidant enzymes were measured in cultured orbital fibroblasts from GO patients and age-matched normal controls in response to 200 μM hydrogen peroxide (H(2)O(2)).

RESULTS

GO fibroblasts had increased basal levels of malondialdehyde (MDA), 8-hydroxy 2'-deoxyguanosine, superoxide anions, H(2)O(2), and manganese-dependent superoxide dismutase (Mn-SOD) activity, as well as decreased glutathione peroxidase (GPx) activity and the ratio between reduced (GSH) and oxidized glutathione (GSSG) compared with the orbital fibroblasts from normal subjects. After treatment of the cells with 200 μM H(2)O(2), the amplitude of increase in the intracellular levels of MDA (63% versus 26%), H(2)O(2) (24% versus 13%) and Mn-SOD activity (48% versus 23%) was exaggerated in GO fibroblasts compared with normal controls, respectively. In addition, treatment of GO fibroblasts with 200 μM H(2)O(2) led to a dramatic reduction of catalase activity (-59% versus -29%), GPx activity (-56% versus -13%), and GSH/GSSG ratio (-49% versus -21%), respectively.

CONCLUSIONS

Elevated ROS and redox imbalance in GO orbital fibroblasts were exacerbated by H(2)O(2) as a result of exhaustion of GSH and compromise of antioxidant enzymes. Hypersensitivity to oxidative stress of GO orbital fibroblasts may play a role in the pathogenesis of GO.

Regulation of Lymphocyte Function by PPARgamma: Relevance to Thyroid Eye Disease-Related Inflammation

Thyroid eye disease (TED) is an autoimmune condition in which intense inflammation leads to orbital tissue remodeling, including the accumulation of extracellular macromolecules and fat. Disease progression depends upon interactions between lymphocytes and orbital fibroblasts. These cells engage in a cycle of reciprocal activation which produces the tissue characteristics of TED. Peroxisome proliferator-activated receptor-gamma (PPARgamma) may play divergent roles in this process, both attenuating and promoting disease progression. PPARgamma has anti-inflammatory activity, suggesting that it could interrupt intercellular communication. However, PPARgamma activation is also critical to adipogenesis, making it a potential culprit in the pathological fat accumulation associated with TED. This review explores the role of PPARgamma in TED, as it pertains to crosstalk between lymphocytes and fibroblasts and the development of therapeutics targeting cell-cell interactions mediated through this signaling pathway.

Divergent Sp1 protein levels may underlie differential expression of UDP-glucose dehydrogenase by fibroblasts: role in susceptibility to orbital Graves disease

UDP-glucose dehydrogenase (UGDH) catalyzes the formation of UDP-glucuronate. Glucuronate represents an integral component of the glycosaminoglycan, hyaluronan, which accumulates in orbital Graves disease. Here we report that orbital fibroblasts express higher levels of UGDH than do those from skin. This is a consequence of greater UGDH gene promoter activity and more abundant steady-state UGDH mRNA. Six Sp1 sites located in the proximal 550 bp of the UGDH gene promoter appear to determine basal promoter activity, as does a previously unrecognized 49-bp sequence spanning -1436 nucleotides (nt) and -1388 nt that negatively affects activity. Nuclear Sp1 protein is more abundant in orbital fibroblasts, and its binding to specific sites on DNA is greater than that in dermal fibroblasts. Mutating each of these Sp1 sites in a UGDH gene promoter fragment, extending from -1387 to +71 nt and fused to a luciferase reporter, results in divergent activities when transfected in orbital and dermal fibroblasts. Reducing Sp1 attenuated UGDH gene promoter activity, lowered steady-state UGDH mRNA levels, and reduced UGDH enzyme activity. Targeting Sp1 and UGDH with specific siRNAs also lowered hyaluronan synthase-1 (HAS-1) and HAS-2 levels and reduced hyaluronan accumulation in orbital fibroblasts. These findings suggest that orbital fibroblasts express high levels of UGDH in an anatomic-specific manner, apparently the result of greater constitutive Sp1. These high UGDH levels may underlie susceptibility of the orbit to localized overproduction of hyaluronan in Graves disease.

An anti-inflammatory selective glucocorticoid receptor modulator preserves osteoblast differentiation

Glucocorticoids (GCs) are in widespread use to treat inflammatory bone diseases, such as rheumatoid arthritis (RA). Their anti-inflammatory efficacy, however, is accompanied by deleterious effects on bone, leading to GC-induced osteoporosis (GIO). These effects include up-regulation of the receptor activator of NF-κB ligand/osteoprotegerin (RANKL/OPG) ratio to promote bone-resorbing osteoclasts and include inhibition of bone-forming osteoblasts. We previously identified suppression of osteoblast differentiation by the monomer glucocorticoid receptor (GR) via the inhibition of Il11 expression as a crucial mechanism for GIO. Here we show that the GR-modulating substance compound A (CpdA), which does not induce GR dimerization, still suppresses proinflammatory cytokines in fibroblast-like synovial cells from patients with RA and in osteoblasts. In contrast to the full GR agonist dexamethasone, it does not unfavorably alter the RANKL/OPG ratio and does not affect Il11 expression and subsequent STAT3 phosphorylation in these cells. Notably, while dexamethasone inhibits osteoblast differentiation, CpdA does not affect osteoblast differentiation in vitro and in vivo. We describe here for the first time that selective GR modulators can act against inflammation, while not impairing osteoblast differentiation.

Peptidoglycan recognition proteins protect mice from experimental colitis by promoting normal gut flora and preventing induction of interferon-gamma

There are multiple mechanisms that protect the intestine from an excessive inflammatory response to intestinal microorganisms. We report here that all four mammalian peptidoglycan recognition proteins (PGRPs or Pglyrps) protect the host from colitis induced by dextran sulfate sodium (DSS). Pglyrp1(-/-), Pglyrp2(-/-), Pglyrp3(-/-), and Pglyrp4(-/-) mice are all more sensitive than wild-type mice to DSS-induced colitis due to a more inflammatory gut microflora, higher production of interferon-gamma, higher expression of interferon-inducible genes, and an increased number of NK cells in the colon upon initial exposure to DSS, which leads to severe hyperplasia of the lamina propria, loss of epithelial cells, and ulceration in the colon. Thus, during experimental colitis, PGRPs protect the colon of wild-type mice from an early inflammatory response and the loss of the barrier function of intestinal epithelium by promoting normal bacterial flora and by preventing damaging production of interferon-gamma by NK cells in response to injury.

Cell-cycle inhibition by Helicobacter pylori L-asparaginase

Helicobacter pylori (H. pylori) is a major human pathogen causing chronic gastritis, peptic ulcer, gastric cancer, and mucosa-associated lymphoid tissue lymphoma. One of the mechanisms whereby it induces damage depends on its interference with proliferation of host tissues. We here describe the discovery of a novel bacterial factor able to inhibit the cell-cycle of exposed cells, both of gastric and non-gastric origin. An integrated approach was adopted to isolate and characterise the molecule from the bacterial culture filtrate produced in a protein-free medium: size-exclusion chromatography, non-reducing gel electrophoresis, mass spectrometry, mutant analysis, recombinant protein expression and enzymatic assays. L-asparaginase was identified as the factor responsible for cell-cycle inhibition of fibroblasts and gastric cell lines. Its effect on cell-cycle was confirmed by inhibitors, a knockout strain and the action of recombinant L-asparaginase on cell lines. Interference with cell-cycle in vitro depended on cell genotype and was related to the expression levels of the concurrent enzyme asparagine synthetase. Bacterial subcellular distribution of L-asparaginase was also analysed along with its immunogenicity. H. pylori L-asparaginase is a novel antigen that functions as a cell-cycle inhibitor of fibroblasts and gastric cell lines. We give evidence supporting a role in the pathogenesis of H. pylori-related diseases and discuss its potential diagnostic application.

Human bone marrow stromal cells and skin fibroblasts inhibit natural killer cell proliferation and cytotoxic activity

Mesenchymal stromal cells (MSCs) are potent immunomodulators that have successfully been used to circumvent various types of inflammations, including steroid-resistant graft-versus-host disease. Although initially believed to be restricted to multipotent MSCs, this immunoregulatory function is shared with differentiated cells from the mesenchymal lineage such as skin fibroblasts (SFs). Mesenchymal cell-induced immunoregulation is so potent that it may allow the reactivation of dormant malignancies, a fact that would preclude using such cells as therapeutic agents. Because NK cells are pivotal effectors controlling tumor cell containment we investigated the effect of allogenic MSCs and SFs on NK cell function in vitro. When NK cells were incubated with IL-15 and MSCs or SFs for 6 days, their proliferation and cytotoxic activity were significantly decreased compared to NK cells cultured with IL-15 alone or with human venous endothelial cells. Cytotoxic activity inhibition reached 86% when assayed on MHC-I(+) allogenic primary hematopoietic blasts, and was associated with a significant decrease in cytolytic granule exocytosis and in perforin release. Stromal cell-mediated inhibition was effective only if cell-cell proximity was long lasting: when NK cells were activated with IL-15 in the absence of MSCs and assayed for cytotoxicity in their presence no inhibition occurred. MSC inhibition was ultimately mediated by a soluble factor generated upon incubation with NK cells activated by IL-15 or IL-2. The indoleamine 2,3 dioxygenase was activated in MSCs and SFs because L-kynurenine was detected in inhibitory supernatants, but its blockade did not restore NK cell functions. The profound inhibition of cytotoxic activity directed against allogenic hematopoietic blasts exerted by MSCs and SFs on NK cells may be a concern. Should this occur in vivo it may induce the inability of NK cells to control residual or dormant malignant diseases after infusion of therapeutic MSCs.

Novel anti-adipogenic activity produced by human fibroblasts

Fatty tissue is generally found in distinct "depots" distributed throughout the human body. Adipocytes from each of the various depots differ in their metabolic capacities and their responses to environmental stimuli. Although a general understanding of the factors responsible for adipogenic transformation has been achieved, much is not understood about the mechanisms of adipose tissue deposition and the phenotypes of the adipocytes found within each depot. A clue to the factors regulating fat deposition may come from studies of adipogenesis using primary human orbital fibroblasts from patients with thyroid eye disease, a condition in which intense inflammation leads to expansion of orbital adipose tissue via differentiation of fibroblasts to adipocytes. We have previously demonstrated that adipogenesis of orbital fibroblasts is negatively correlated with cellular expression of the Thy-1 surface marker. In this study, we developed a novel imaging flow cytometric approach for the assessment of adipogenesis to test the hypothetical dependence of adipogenic potential on lack of Thy-1 expression. Using this technique, we learned that Thy-1-positive fibroblasts are, in fact, capable of differentiating into adipocytes but are less likely to do so because they secrete a paracrine anti-adipogenic factor. It is possible that such a factor plays an important role in the prevention of excess fat deposition in the normal orbit and may even be exploited as a therapy for the treatment of obesity, a major worldwide health concern.