MicroRNA markers of inflammation and remodelling in temporal arteries from patients with giant cell arteritis

The IL-6 axis in vascular inflammation: effects of IL-6 receptor blockade on vascular lesions from patients with giant-cell arteritis

OBJECTIVES

Blocking interleukin (IL)-6-receptor with tocilizumab has been a major advance in the treatment of giant-cell arteritis (GCA), supporting a crucial role of IL-6 receptor signalling. However, nearly half of the patients are not able to maintain glucocorticoid- free remission with tocilizumab. The impact of tocilizumab on vascular lesions of GCA is largely unknown since conflicting results have been obtained by imaging. The expression and functional role of IL-6-receptor in GCA immunopathology has not been previously investigated. This study aimed to investigate expression of IL-6 receptor in GCA and control arteries and to assess the impact of tocilizumab on ex vivo-cultured temporal arteries and aortic tissue from patients with GCA.

METHODS

This study used a hypothesis-driven, candidate molecule transcriptomic approach using ex vivo temporal artery and aortic tissue culture, quantitative real-time polymerase chain reaction, immunofluorescence, Western Blot, immunoassay, adhesion, and chemotaxis assays.

RESULTS

IL-6 receptor protein expressed intensively in GCA compared with that in control arteries. Tocilizumab decreased expression/phosphorylation of STAT3 and reduced expression of STAT3-dependent molecules including suppressor of cytokine signalling 3, CCL-2, and ICAM-1 in cultured GCA-involved arteries and patients' peripheral blood mononuclear cells (PBMCs). A similar trend was observed in aortic tissue. Consistently, tocilizumab reduced PBMC adhesiveness to vascular smooth muscle cells and human umbilical vein endothelial cells and chemotaxis towards supernatants of tocilizumab-treated GCA arteries. In some specimens, tocilizumab increased STAT1 phosphorylation and expression of STAT1-dependent chemokines including CXCL9 and CXCL10.

CONCLUSIONS

Tocilizumab has a significant impact on vascular lesions by reducing, but not abrogating, key molecules involved in PBMC recruitment. About half of the patients may activate alternative inflammatory pathways in their lesions as a potential escape mechanism to tocilizumab that deserves further investigation.

Current state of epigenetics in giant cell arteritis: Focus on microRNA dysregulation

Giant cell arteritis (GCA) is a primary systemic vasculitis affecting the elderly, characterized by a granulomatous vessel wall inflammation of large- and medium-sized arteries. The immunopathology of GCA is complex, involving both the innate and adaptive arms of the immune system, where a maladaptive inflammatory-driven vascular repair process ultimately results in vessel wall thickening, intramural vascular smooth muscle cell proliferation, neovascularization and vessel lumen occlusion, which can lead to serious ischemic complications such as visual loss and ischemic stroke. Over the past decade, microRNA (miRNA) dysregulation has been highlighted as an important contributing factor underlying the pathogenesis of GCA. Since current understanding of miRNA involvement in GCA remains largely based on extrapolation of previously determined miRNA functions in vitro or in loss- or gain-of-function studies, an overall insight into the role of miRNA alteration in GCA pathophysiology remains limited. In this narrative review, we summarize the current knowledge on aberrantly expressed miRNAs in GCA and thoroughly discuss the impact of their altered regulatory role in the context of GCA setting. Furthermore, we address challenges and future perspectives in utilization of miRNA-based diagnostic and prognostic biomarkers of GCA in clinical settings.

Tissue degrading and remodelling molecules in giant cell arteritis

OBJECTIVES

GCA is a granulomatous vasculitis affecting large vessels, leading to intimal occlusion accompanied by the accumulation of myofibroblasts. Histopathologically, GCA is characterized by destruction of the tunica media and hypertrophy of the intima with invasion of activated CD4+ T cells, macrophages and multinucleated giant cells (MNGCs). Despite these well-defined histopathological features, the molecular pathology of GCA has largely remained elusive. We aimed to characterize the pathologic features of GCA at the molecular level.

METHODS

To identify key molecules involved in GCA pathogenesis, we conducted genome-wide gene expression profiling on arterial lesions obtained through temporal artery biopsy of 16 patients who had not received any prior treatment. The resulting data were examined to reveal specific pathways and genes, and some of the molecules were followed up by immunohistochemistry.

RESULTS

Our analysis revealed a unique gene expression pattern in GCA lesions, including enrichment of immune cells and phagocytic pathways related to microglia and osteoclasts. Subsequent immunohistochemistry analysis identified the presence of MMP12 (macrophage elastase), HLA-DRA, and phagocytosis- and osteoclast-associated molecules in infiltrating macrophages and MNGCs. Additionally, we discovered LRRC15-expressing cells in the tunica intima, suggesting a myofibroblast subpopulation that suppresses cytotoxic CD8+ T cells. These molecules were upregulated in other granulomatous diseases affecting not only arteries but also lymph nodes.

CONCLUSION

Our study revealed novel molecules associated with the pathological features of GCA, providing a foundation for better understanding of GCA pathogenesis and development of targeted therapeutic strategies.

Genes deregulated in giant cell arteritis by Nanostring nCounter gene expression profiling in temporal artery biopsies

OBJECTIVE

To identify differentially expressed genes in temporal artery biopsies (TABs) from patients with giant cell arteritis (GCA) with different histological patterns of inflammation: transmural inflammation (TMI) and inflammation limited to adventitia (ILA), compared with normal TABs from patients without GCA.

METHODS

Expression of 770 immune-related genes was profiled with the NanoString nCounter PanCancer Immune Profiling Panel on formalin-fixed paraffin-embedded TABs from 42 GCA patients with TMI, 7 GCA patients with ILA and 7 non-GCA controls.

RESULTS

Unsupervised clustering of the samples revealed two distinct groups: normal TABs and TABs with ILA in one group, 41/42 TABs with TMI in the other one. TABs with TMI showed 31 downregulated and 256 upregulated genes compared with normal TABs; they displayed 26 downregulated and 187 upregulated genes compared with TABs with ILA (>2.0 fold changes and adjusted p values <0.05). Gene expression in TABs with ILA resembled normal TABs although 38 genes exhibited >2.0 fold changes, but these changes lost statistical significance after Benjamini-Yekutieli correction. Genes encoding TNF superfamily members, immune checkpoints, chemokine and chemokine receptors, toll-like receptors, complement molecules, Fc receptors for IgG antibodies, signalling lymphocytic activation molecules, JAK3, STAT1 and STAT4 resulted upregulated in TMI.

CONCLUSIONS

TABs with TMI had a distinct transcriptome compared with normal TABs and TABs with ILA. The few genes potentially deregulated in ILA were also deregulated in TMI. Gene profiling allowed to deepen the knowledge of GCA pathogenesis.

Altered Plasma Levels and Tissue Expression of Fibroblast Activation Protein Alpha in Giant Cell Arteritis

OBJECTIVE

Giant cell arteritis (GCA) is characterized by granulomatous inflammation of the medium- and large-sized arteries accompanied by remodeling of the vessel wall. Fibroblast activation protein alpha (FAP) is a serine protease that promotes both inflammation and fibrosis. Here, we investigated the plasma levels and vascular expression of FAP in GCA.

METHODS

Plasma FAP levels were measured with enzyme-linked immunosorbent assay in treatment-naive patients with GCA (n = 60) and polymyalgia rheumatica (PMR) (n = 63) compared with age- and sex-matched healthy controls (HCs) (n = 42) and during follow-up, including treatment-free remission (TFR). Inflamed temporal artery biopsies (TABs) of patients with GCA (n = 9), noninflamed TABs (n = 14), and aorta samples from GCA-related (n = 9) and atherosclerosis-related aneurysm (n = 11) were stained for FAP using immunohistochemistry. Immunofluorescence staining was performed for fibroblasts (CD90), macrophages (CD68/CD206/folate receptor beta), vascular smooth muscle cells (desmin), myofibroblasts (α-smooth muscle actin), interleukin-6 (IL-6), and matrix metalloproteinase-9 (MMP-9).

RESULTS

Baseline plasma FAP levels were significantly lower in patients with GCA compared with patients with PMR and HCs and inversely correlated with systemic markers of inflammation and angiogenesis. FAP levels decreased even further at 3 months on remission in patients with GCA and gradually increased to the level of HCs in TFR. FAP expression was increased in inflamed TABs and aorta of patients with GCA compared with control tissues. FAP was abundantly expressed in fibroblasts and macrophages. Some of the FAP+ fibroblasts expressed IL-6 and MMP-9.

CONCLUSION

FAP expression in GCA is clearly modulated both in plasma and in vessels. FAP may be involved in the inflammatory and remodeling processes in GCA and have utility as a target for imaging and therapeutic intervention.

Vascular disease persistence in giant cell arteritis: are stromal cells neglected?

Giant cell arteritis (GCA), the most common systemic vasculitis, is characterised by aberrant interactions between infiltrating and resident cells of the vessel wall. Ageing and breach of tolerance are prerequisites for GCA development, resulting in dendritic and T-cell dysfunction. Inflammatory cytokines polarise T-cells, activate resident macrophages and synergistically enhance vascular inflammation, providing a loop of autoreactivity. These events originate in the adventitia, commonly regarded as the biological epicentre of the vessel wall, with additional recruitment of cells that infiltrate and migrate towards the intima. Thus, GCA-vessels exhibit infiltrates across the vascular layers, with various cytokines and growth factors amplifying the pathogenic process. These events activate ineffective repair mechanisms, where dysfunctional vascular smooth muscle cells and fibroblasts phenotypically shift along their lineage and colonise the intima. While high-dose glucocorticoids broadly suppress these inflammatory events, they cause well known deleterious effects. Despite the emerging targeted therapeutics, disease relapse remains common, affecting >50% of patients. This may reflect a discrepancy between systemic and local mediators of inflammation. Indeed, temporal arteries and aortas of GCA-patients can show immune-mediated abnormalities, despite the treatment induced clinical remission. The mechanisms of persistence of vascular disease in GCA remain elusive. Studies in other chronic inflammatory diseases point to the fibroblasts (and their lineage cells including myofibroblasts) as possible orchestrators or even effectors of disease chronicity through interactions with immune cells. Here, we critically review the contribution of immune and stromal cells to GCA pathogenesis and analyse the molecular mechanisms by which these would underpin the persistence of vascular disease.

miR-146a and miR-146b regulate the expression of ICAM-1 in giant cell arteritis

Giant cell arteritis (GCA) is an inflammatory disease of large/medium-sized arteries. MiRNAs are small, non-coding RNAs that inhibit gene expression at post-transcriptional level. Several miRNAs have been shown to be dysregulated in temporal artery biopsies (TABs) from GCA patients, but their role is unknown. The aims of the present work were: to gain insight into the link between inflammation and miRNA up-regulation in GCA; to identify the role of miR-146a and miR-146b. Primary cultures from TABs were treated with IL-1β, IL-6, soluble IL-6R (sIL6R), IL-17, IL-22, IFNγ, LPS and PolyIC. Correlations between cytokine mRNA and miRNA levels were determined in inflamed TABs. Primary cultures from TABs, human aortic endothelial and smooth muscle cells and ex-vivo TAB sections were transfected with synthetic miR-146a and miR-146b to mimic miRNA activities. Cell viability, target gene expression, cytokine levels in culture supernatants were assayed. Treatment of primary cultures from TABs with IL-1β and IL-17 increased miR-146a expression while IL-1β, IL-6+sIL6R and IFNγ increased miR-146b expression. IFNγ and IL-1β mRNA levels correlated with miR-146a/b levels. Following transfection, cell viability decreased only in primary cultures from TABs. Moreover, transfection of miR-146a/b mimics increased ICAM-1 gene expression and production of the soluble form of ICAM-1 by primary cultures from TABs and by ex-vivo TABs. ICAM-1 expression was higher in inflamed than normal TABs and ICAM-1 levels correlated with miR-146a/b levels. Expression of miR-146a and miR-146b in GCA appeared to be driven by inflammatory cytokines (e.g. IL-1β, IFNγ). miR-146a and miR-146b seem responsible for the increase of soluble ICAM-1.

Role of non-coding RNAs and exosomal non-coding RNAs in vasculitis: A narrative review

A category of very uncommon systemic inflammatory blood vessel illnesses known as vasculitides. The pathogenesis and etiology of vasculitis are still poorly known. Despite all of the progress made in understanding the genetics and causes behind vasculitis, there is still more to learn. Epigenetic dysregulation is a significant contributor to immune-mediated illnesses, and epigenetic aberrancies in vasculitis are becoming more widely acknowledged. Less than 2 % of the genome contains protein-encoding DNA. Studies have shown that a variety of RNAs originating from the non-coding genome exist. Long non-coding RNAs (lncRNAs), microRNAs (miRNAs), and circular RNAs (circRNAs) have attracted the most attention in recent years as they are becoming more and more important regulators of different biological processes, such as diseases of the veins. Extracellular vehicles (EVs) such as exosomes, are membrane-bound vesicular structures that break free either during programmed cell death, such as apoptosis, pyroptosis, and necroptosis or during cell activation. Exosomes may be involved in harmful ways in inflammation, procoagulation, autoimmune reactions, endothelial dysfunction/damage, intimal hyperplasia and angiogenesis, all of which may be significant in vasculitis. Herein, we summarized various non-coding RNAs that are involved in vasculitides pathogenesis. Moreover, we highlighted the role of exosomes in vasculitides.

Senescent cells in giant cell arteritis display an inflammatory phenotype participating in tissue injury via IL-6-dependent pathways

OBJECTIVES

Age is the strongest risk factor of giant cell arteritis (GCA), implying a possible pathogenetic role of cellular senescence. To address this question, we applied an established senescence specific multimarker algorithm in temporal artery biopsies (TABs) of GCA patients.

METHODS

75(+) TABs from GCA patients, 22(-) TABs from polymyalgia rheumatica (PMR) patients and 10(-) TABs from non-GCA/non-PMR patients were retrospectively retrieved and analysed. Synovial tissue specimens from patients with inflammatory arthritis and aorta tissue were used as disease control samples. Senescent cells and their histological origin were identified with specific cellular markers; IL-6 and MMP-9 were investigated as components of the senescent associated secretory phenotype by triple costaining. GCA or PMR artery culture supernatants were applied to fibroblasts, HUVECs and monocytes with or without IL-6R blocking agent to explore the induction of IL-6-associated cellular senescence.

RESULTS

Senescent cells were present in GCA arteries at higher proportion compared with PMR (9.50% vs 2.66%, respectively, p<0.0001) and were mainly originated from fibroblasts, macrophages and endothelial cells. IL-6 was expressed by senescent fibroblasts, and macrophages while MMP-9 by senescent fibroblasts only. IL-6(+) senescent cells were associated with the extension of vascular inflammation (transmural inflammation vs adventitia limited disease: 10.02% vs 4.37%, respectively, p<0.0001). GCA but not PMR artery culture supernatant could induce IL-6-associated senescence that was partially inhibited by IL-6R blockade.

CONCLUSIONS

Senescent cells with inflammatory phenotype are present in GCA arteries and are associated with the tissue inflammatory bulk, suggesting a potential implication in disease pathogenesis.

Giant Cell Arteritis: Advances in Understanding Pathogenesis and Implications for Clinical Practice

Giant cell arteritis (GCA) is a noninfectious granulomatous vasculitis of unknown etiology affecting individuals older than 50 years. Two forms of GCA have been identified: a cranial form involving the medium-caliber temporal artery causing temporal arteritis (TA) and an extracranial form involving the large vessels, mainly the thoracic aorta and its branches. GCA generally affects individuals with a genetic predisposition, but several epigenetic (micro)environmental factors are often critical for the onset of this vasculitis. A key role in the pathogenesis of GCA is played by cells of both the innate and adaptive immune systems, which contribute to the formation of granulomas that may include giant cells, a hallmark of the disease, and arterial tertiary follicular organs. Cells of the vessel wall cells, including vascular smooth muscle cells (VSMCs) and endothelial cells, actively contribute to vascular remodeling responsible for vascular stenosis and ischemic complications. This review will discuss new insights into the molecular and cellular pathogenetic mechanisms of GCA, as well as the implications of these findings for the development of new diagnostic biomarkers and targeted drugs that could hopefully replace glucocorticoids (GCs), still the backbone of therapy for this vasculitis.

Indication of Activated Senescence Pathways in the Temporal Arteries of Patients With Giant Cell Arteritis

OBJECTIVE

Giant cell arteritis (GCA) affects almost exclusively individuals above 50 years old, suggesting a role of aging-related changes such as cellular senescence in its pathobiology. The kinases p21(WAF1/CIP1) and p16/INK4A play key roles in 2 distinct pathways leading to senescence. The proinflammatory molecules interleukin-6 (IL-6) and granulocyte-macrophage colony-stimulating factor (GM-CSF), which are key components of the senescence-associated secretory phenotype (SASP), are effective targets of treatment in GCA. Here, we aimed to investigate the presence of p21+ and p16+ cells producing these SASP cytokines in temporal artery biopsies (TABs) of patients with GCA.

METHODS

Eight patients with GCA and 14 age-matched, non-GCA individuals who underwent a TAB were included. Immunohistochemical staining of p21, p16, IL-6, and GM-CSF was performed. Multiplex immunofluorescent staining was performed to investigate the colocalization of p21 and p16 with IL-6, GM-CSF, and immune cell markers (CD68, CD3, CD20).

RESULTS

We found that expression levels of p16, p21, IL-6, and GM-CSF were elevated in the TABs of patients with GCA. Both p16- and p21-expressing cells were mainly found near the internal lamina elastica, especially among giant cells and macrophages, although p21 and p16 expression could be found in all 3 layers of the vessels. Expression of p16 and p21 was occasionally found in T cells but not B cells. The p16+ and p21+ cells expressing GM-CSF/IL-6 were detected throughout the TABs.

CONCLUSION

Our data suggest the presence of activated senescence pathways at the site of vascular inflammation in GCA and support further research into the role of senescence in the pathophysiology of GCA.

T cell aging as a risk factor for autoimmunity

Immune aging is a complex process rendering the host susceptible to cancer, infection, and insufficient tissue repair. Many autoimmune diseases preferentially occur during the second half of life, counterintuitive to the concept of excess adaptive immunity driving immune-mediated tissue damage. T cells are particularly susceptible to aging-imposed changes, as they are under extreme proliferative pressure to fulfill the demands of clonal expansion and of homeostatic T cell repopulation. T cells in older adults have a footprint of genetic and epigenetic changes, lack mitochondrial fitness, and fail to maintain proteostasis, diverging them from host protection to host injury. Here, we review recent progress in understanding how the human T-cell system ages and the evidence detailing how T cell aging contributes to autoimmune conditions. T cell aging is now recognized as a risk determinant in two prototypic autoimmune syndromes; rheumatoid arthritis and giant cell arteritis. The emerging concept adds susceptibility to autoimmune and autoinflammatory disease to the spectrum of aging-imposed adaptations and opens new opportunities for immunomodulatory therapy by restoring the functional intactness of aging T cells.

Evaluation of Arterial Histopathology and microRNA Expression That Underlie Ultrasonography Findings in Temporal Arteries of Patients with Giant Cell Arteritis

The aim of this study was to assess the interrelation between vascular ultrasonography (US) findings, histopathological data, and the expression of selected dysregulated microRNAs (miRNAs) in giant cell arteritis (GCA). The study included data on the clinical parameters, US measurements, and temporal artery biopsies (TABs) of 46 treatment-naïve patients diagnosed with GCA and 22 age-matched non-GCA patient controls. We performed a comprehensive comparative and correlation analysis along with generation of receiver operating characteristic (ROC) curves to ascertain the diagnostic performance of US examination parameters and selected miRNAs for GCA diagnosis. We showed significant differences in the US-measured intima-media thickness of the temporal arteries, the presence of a halo sign, and the presence of luminal stenosis between GCA-positive/TAB-positive, GCA-positive/TAB-negative, and non-GCA patients. Correlation analysis revealed significant associations between several histopathological parameters, US-measured intima-media thickness, and the halo sign. We found that the significant overexpression of miR-146b-5p, miR-155-5p, miR-511-5p, and miR-21-5p, and the under-expression of the miR-143/145 cluster, miR-30a-5p, and miR-125a-5p, coincides and is associated with the presence of a halo sign in patients with GCA. Notably, we determined a high diagnostic performance of miR-146b-5p, miR-21-3p, and miR-21-5p expression profiles in discriminating GCA patients from non-GCA controls, suggesting their potential utilization as putative biomarkers of GCA. Taken together, our study provides an insight into the US-based diagnostic evaluation of GCA by revealing the complex interrelation of clearly defined image findings with underlying vascular immunopathology and altered arterial tissue-specific miRNA profiles.

The role of hypoxia-associated miRNAs in acquired sensorineural hearing loss

Introduction: Sensorineural hearing loss (SNHL) is a prevalent sensory deficit presenting commonly as age-related hearing loss. Other forms of SNHL include noise-induced and sudden SNHL. Recent evidence has pointed to oxidative stress as a common pathogenic pathway in most subtypes of acquired SNHL. MicroRNAs (miRNAs) are small non-coding RNA sequences that suppress target mRNA expression and affect downstream processes. Many studies have shown that miRNAs are integral biomolecules in hypoxia-adaptive responses. They also promote apoptosis in response to oxidative stress resulting in SNHL. Our hypothesis is that miRNAs are involved in the pathophysiological responses to hypoxia and oxidative stress that result in SNHL. This study reviews the evidence for hypoxia-adaptive miRNAs (hypoxamiRs) in different types of acquired SNHL and focuses on miRNAs involved in hypoxia driven SNHL. Methods: Electronic bibliographic databases PubMed, Ovid MEDLINE, Ovid EMBASE, and Web of Science Core Collection were searched independently by two investigators for articles published in English from the inception of individual databases to the end of July 2020. The text word or medical subject heading searches of all fields, titles, abstracts, or subject headings depending on the database were undertaken with combinations of the words "microRNAs", "hypoxia", "hypoxamiRs", "oxidative stress", "ischemia" and "hearing loss". The reference lists of studies meeting the inclusion criteria were searched to identify additional relevant studies. The inclusion criteria included relevant clinical studies with human subjects, animals, and in vitro experiments. The risk of bias was assessed using the Cochrane risk of bias assessment tool for human studies and the Systematic Review Center for Laboratory animal Experimentation (SYRCLE) a risk of bias assessment tool for animal model and in vitro studies. Results: A total of 15 primary articles were selected for full text screening after excluding duplicates, reviews, retracted articles, and articles not published in English. All nine articles meeting the study inclusion criteria were from animal or in vitro model studies and were assessed to be at low risk of bias. miRNAs miR-34a and miR-29b were reported to be involved in SNHL in inner ear cell models exposed to oxidative stress. Signaling pathways Sirtuin 1/peroxisome proliferator-activated receptor gamma coactivator-1-alpha (SIRT1/PGC-1α), SIRT1/p53, and SIRT1/hypoxia-inducible factor 1-alpha (HIF-1α) were identified as underlying pathways involved in acquired SNHL. Conclusion: There is evidence that miR-34a and -29b are involved in hypoxia-driven and other causes of oxidative stress-related acquired SNHL. Further studies are required to determine if these findings are clinically applicable.

The innate face of Giant Cell Arteritis: Insight into cellular and molecular innate immunity pathways to unravel new possible biomarkers of disease

Giant cell arteritis (GCA) is an inflammatory chronic disease mainly occurring in elderly individuals. The pathogenesis of GCA is still far from being completely elucidated. However, in susceptible arteries, an aberrant immune system activation drives the occurrence of vascular remodeling which is mainly characterized by intimal hyperplasia and luminal obstruction. Vascular damage leads to ischemic manifestations involving extra-cranial branches of carotid arteries, mostly temporal arteries, and aorta. Classically, GCA was considered a pathological process resulting from the interaction between an unknown environmental trigger, such as an infectious agent, with local dendritic cells (DCs), activated CD4 T cells and effector macrophages. In the last years, the complexity of GCA has been underlined by robust evidence suggesting that several cell subsets belonging to the innate immunity can contribute to disease development and progression. Specifically, a role in driving tissue damage and adaptive immunity activation was described for dendritic cells (DCs), monocytes and macrophages, mast cells, neutrophils and wall components, such as endothelial cells (ECs) and vascular smooth muscle cells (VSMCs). In this regard, molecular pathways related to cytokines, chemokines, growth factors, vasoactive molecules and reactive oxygen species may contribute to the inflammatory process underlying GCA. Altogether, innate cellular and molecular pathways may clarify many pathogenetic aspects of the disease, paving the way for the identification of new biomarkers and for the development of new treatment targets for GCA. This review aims to deeply dissect past and new evidence on the innate immunological disruption behind GCA providing a comprehensive description of disease development from the innate perspective.

Inflammatory Cell Composition and Immune-Related microRNA Signature of Temporal Artery Biopsies From Patients With Giant Cell Arteritis

Objectives

The aim of this study was to quantitatively assess distinct immune cell subsets comprising inflammatory infiltrate in temporal artery biopsies (TABs) from patients with giant cell arteritis (GCA), and to link the obtained histopathological data with expression profiles of immune-related microRNAs (miRNAs).

Methods

The study included 68 formalin-fixed, paraffin-embedded TABs from treatment-naïve patients, including 30 histologically positive GCA and 16 negative GCA TABs, and 22 control non-GCA TABs. Quantitative assessment of histological parameters was performed using histopathological and immunohistochemical techniques. miRNA expression analysis was performed by quantitative real-time PCR.

Results

Intense transmural mononuclear inflammatory infiltrates in TAB-positive GCA arteries were predominantly composed of CD3⁺, CD4⁺ and CD8⁺ T lymphocytes, and CD68⁺ macrophages, accompanied by a strong nuclear overexpression of the nuclear factor of activated T cells, cytoplasmic 1 (NFATC) in the lymphocyte infiltrate fraction. Furthermore, TAB-positive GCA arteries were characterized by significant overexpression of nine pro-inflammatory miRNAs (miR-132-3p/-142-3p/-142-5p/-155-5p/-210-3p/-212-3p/-326/-342-5p/-511-5p) and a significant under-expression of six regulatory immune-related miRNAs (miR-30a-5p/-30b-5p/-30c-5p/-30d-5p/-30e-5p/-124-3p), whose expression levels significantly associated with most evaluated histopathological parameters. Notably, we revealed miR-132-3p/-142-3p/-142-5p/-155-5p/-212-3p/-511-5p as major promoters of arterial inflammation and miR-30a-5p/-30c-5p/-30d-5p as putative regulators of NFATC signaling in TAB-positive GCA arteries.

Conclusion

Overall, we demonstrated that an altered arterial tissue-specific pro-inflammatory miRNA signature favors enhanced T cell-driven inflammation and macrophage activity in TAB-positive GCA arteries. Moreover, dysregulation of several immune-related miRNAs seems to contribute crucially to GCA pathogenesis, through impairing their regulatory activity towards T cell-mediated immune responses driven by the calcineurin (CaN)/NFAT signaling pathway, indicating their therapeutic, diagnostic and prognostic potential.

Age as a risk factor in vasculitis

Two vasculitides, giant cell arteritis (GCA) and Takayasu arteritis (TAK), are recognized as autoimmune and autoinflammatory diseases that manifest exclusively within the aorta and its large branches. In both entities, the age of the affected host is a critical risk factor. TAK manifests during the 2nd-4th decade of life, occurring while the immune system is at its height of performance. GCA is a disease of older individuals, with infrequent cases during the 6th decade and peak incidence during the 8th decade of life. In both vasculitides, macrophages and T cells infiltrate into the adventitia and media of affected vessels, induce granulomatous inflammation, cause vessel wall destruction, and reprogram vascular cells to drive adventitial and neointimal expansion. In GCA, abnormal immunity originates in an aged immune system and evolves within the aged vascular microenvironment. One hallmark of the aging immune system is the preferential loss of CD8⁺ T cell function. Accordingly, in GCA but not in TAK, CD8⁺ effector T cells play a negligible role and anti-inflammatory CD8⁺ T regulatory cells are selectively impaired. Here, we review current evidence of how the process of immunosenescence impacts the risk for GCA and how fundamental differences in the age of the immune system translate into differences in the granulomatous immunopathology of TAK versus GCA.

New insights into the pathogenesis of giant cell arteritis: are they relevant for precision medicine?

Giant cell arteritis is a primary granulomatous vasculitis characterised by a strict tissue tropism for large and medium-size vessels, occurring in people older than 50 years. Although considerable progress in understanding some of the pathophysiological mechanisms involved in the pathogenesis of giant cell arteritis has been made in the past 10 years, specific triggers of disease and mechanisms of chronic damage have not yet been identified. The definition of a specific pro-inflammatory hierarchy between the multiple cell types and the different cytokines or chemokines involved in the inflammatory process are still unexplored areas of study. The overall goal of precision medicine is to identify the best possible therapeutic approach for an individual or group of individuals with a given disease. The fundamental prerequisite of this approach is the identification, at baseline, of clinical and imaging findings and of molecular biomarkers that allow a precise stratification of patients and an adequate prediction of the therapeutic response. In this regard, the possibility of obtaining temporal artery biopsies for diagnostic purposes offers incredible exploratory possibilities to define different disease pathotypes potentially susceptible to different therapeutic interventions. In this Series paper, we will describe the most recent evidence relating to the pathogenesis of giant cell arteritis, trying to define, if possible, a new pathogenetic-centred approach to patients with giant cell arteritis.

Dysregulated Expression of Arterial MicroRNAs and Their Target Gene Networks in Temporal Arteries of Treatment-Naïve Patients with Giant Cell Arteritis

In this study, we explored expression of microRNA (miR), miR-target genes and matrix remodelling molecules in temporal artery biopsies (TABs) from treatment-naïve patients with giant cell arteritis (GCA, n = 41) and integrated these analyses with clinical, laboratory, ultrasound and histological manifestations of GCA. NonGCA patients (n = 4) served as controls. GCA TABs exhibited deregulated expression of several miRs (miR-21-5p, -145-5p, -146a-5p, -146b-5p, -155-5p, 424-3p, -424-5p, -503-5p), putative miR-target genes (YAP1, PELI1, FGF2, VEGFA, KLF4) and matrix remodelling factors (MMP2, MMP9, TIMP1, TIPM2) with key roles in Toll-like receptor signaling, mechanotransduction and extracellular matrix biology. MiR-424-3p, -503-5p, KLF4, PELI1 and YAP1 were identified as new deregulated molecular factors in GCA TABs. Quantities of miR-146a-5p, YAP1, PELI1, FGF2, TIMP2 and MMP9 were particularly high in histologically positive GCA TABs with occluded temporal artery lumen. MiR-424-5p expression in TABs and the presence of facial or carotid arteritis on ultrasound were associated with vision disturbances in GCA patients. Correlative analysis of miR-mRNA quantities demonstrated a highly interrelated expression network of deregulated miRs and mRNAs in temporal arteries and identified KLF4 as a candidate target gene of deregulated miR-21-5p, -146a-5p and -155-5p network in GCA TABs. Meanwhile, arterial miR and mRNA expression did not correlate with constitutive symptoms and signs of GCA, elevated markers of systemic inflammation nor sonographic characteristics of GCA. Our study provides new insights into GCA pathophysiology and uncovers new candidate biomarkers of vision impairment in GCA.

Identification of microRNAs and their target gene networks implicated in arterial wall remodelling in giant cell arteritis

OBJECTIVES

To identify dysregulated microRNAs (miRNAs) and their gene targets in temporal arteries from GCA patients, and determine their association with GCA pathogenesis and related arterial wall remodelling.

METHODS

We included 93 formalin-fixed, paraffin-embedded temporal artery biopsies (TABs) from treatment-naïve patients: 54 positive and 17 negative TABs from clinically proven GCA patients, and 22 negative TABs from non-GCA patients. miRNA expression analysis was performed with miRCURY LNA miRNome Human PCR Panels and quantitative real-time PCR. miRNA target gene prediction and pathway enrichment analysis was performed using the miRDB and Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) databases, respectively.

RESULTS

Dysregulation of 356 miRNAs was determined in TAB-positive GCA arteries, among which 78 were significantly under-expressed and 22 significantly overexpressed above 2-fold, when compared with non-GCA controls. Specifically, TAB-positive GCA arteries were characterized by a significant overexpression of 'pro-synthetic' (miR-21-3p/-21-5p/-146a-5p/-146b-5p/-424-5p) and under-expression of 'pro-contractile' (miR-23b-3p/-125a-5p/-143-3p/-143-5p/-145-3p/-145-5p/-195-5p/-365a-3p) vascular smooth muscle cell phenotype-associated regulatory miRNAs. These miRNAs targeted gene pathways involved in the arterial remodelling and regulation of the immune system, and their expression correlated with the extent of intimal hyperplasia in TABs from GCA patients. Notably, the expression of miR-21-3p/-21-5p/-146a-5p/-146b-5p/-365a-3p differentiated between TAB-negative GCA arteries and non-GCA temporal arteries, revealing these miRNAs as potential biomarkers of GCA.

CONCLUSION

Identification of dysregulated miRNAs involved in the regulation of the vascular smooth muscle cell phenotype and intimal hyperplasia in GCA arterial lesions, and detection of their expression profiles, enables a novel insight into the complexity of GCA pathogenesis and implies their potential utilization as diagnostic and prognostic biomarkers of GCA.

miR-146b correlates with increased disease activity and psoriatic tissue inflammation and promotes keratinocyte proliferation in psoriasis

The present study aimed to investigate the expression of microRNA (miR)-146b in psoriatic tissue and its correlation with psoriasis activity and inflammation. The effect of miR-146b overexpression on keratinocyte proliferation and apoptosis was also explored. The expression of miR-146b in the psoriasis-affected tissue and non-affected tissue of 110 patients was determined via reverse transcription-quantitative (RT-q)PCR. The psoriasis-affected body surface area and psoriasis area severity index (PASI) score were recorded for evaluating disease activity. The expression of various inflammatory cytokines in psoriasis-affected tissue was also detected via RT-qPCR. miR-146b overexpression and control plasmids were constructed and transfected into HaCaT cells in vitro. Subsequently, cell proliferation, apoptosis and tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL)-induced cell apoptosis were determined. The results revealed that the expression of miR-146b was increased in psoriasis-affected tissue compared with that in unaffected tissue. The results obtained from a receiver operating characteristic curve analysis demonstrated that miR-146b levels were able to discriminate between psoriasis-affected tissue and unaffected tissue, with an area under the curve value of 0.781 (95% CI: 0.720-0.843). In addition, miR-146b expression in psoriatic tissue was correlated with an increased PASI score in patients with psoriasis. miR-146b expression in psoriatic tissue was positively correlated with TNF-α, interleukin (IL)-6 and IL-17 mRNA levels. In vitro, miR-146b overexpression enhanced HaCaT cell proliferation and suppressed apoptosis as well as TRAIL-induced apoptosis when compared with that in control-transfected HaCaT cells. In conclusion, miR-146b was positively correlated with disease activity and psoriatic tissue inflammation. Keratinocyte proliferation was also promoted in psoriasis.

MicroRNA expression profile in chronic nonbacterial prostatitis revealed by next-generation small RNA sequencing

MicroRNAs (miRNAs) are considered to be involved in the pathogenic initiation and progression of chronic nonbacterial prostatitis (CNP); however, the comprehensive expression profile of dysregulated miRNAs, relevant signaling pathways, and core machineries in CNP have not been fully elucidated. In the current research, CNP rat models were established through the intraprostatic injection of carrageenan into the prostate. Then, next-generation sequencing was performed to explore the miRNA expression profile in CNP. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) bioinformatical analyses were conducted to reveal the enriched biological processes, molecular functions, and cellular components and signaling pathways. As a result, 1224, 1039, and 1029 known miRNAs were annotated in prostate tissues from the blank control (BC), normal saline injection (NS), and carrageenan injection (CAR) groups (n = 3 for each group), respectively. Among them, 84 miRNAs (CAR vs BC) and 70 miRNAs (CAR vs NS) with significantly different expression levels were identified. Compared with previously reported miRNAs with altered expression in various inflammatory diseases, the majority of deregulated miRNAs in CNP, such as miR-146b-5p, miR-155-5p, miR-150-5p, and miR-139-5p, showed similar expression patterns. Moreover, bioinformatics analyses have enriched mitogen-activated protein kinase (MAPK), cyclic adenosine monophosphate (cAMP), endocytosis, mammalian target of rapamycin (mTOR), and forkhead box O (FoxO) signaling pathways. These pathways were all involved in immune response, which indicates the critical regulatory role of the immune system in CNP initiation and progression. Our investigation has presented a global view of the differentially expressed miRNAs and potential regulatory networks containing their target genes, which may be helpful for identifying the novel mechanisms of miRNAs in immune regulation and effective target-specific theragnosis for CNP.

Current State of Precision Medicine in Primary Systemic Vasculitides

Precision medicine (PM) is an emerging data-driven health care approach that integrates phenotypic, genomic, epigenetic, and environmental factors unique to an individual. The goal of PM is to facilitate diagnosis, predict effective therapy, and avoid adverse reactions specific for each patient. The forefront of PM is in oncology; nonetheless, it is developing in other fields of medicine, including rheumatology. Recent studies on elucidating the genetic architecture of polygenic and monogenic rheumatological diseases have made PM possible by enabling physicians to customize medical treatment through the incorporation of clinical features and genetic data. For complex inflammatory disorders, the prevailing paradigm is that disease susceptibility is due to additive effects of common reduced-penetrance gene variants and environmental factors. Efforts have been made to calculate cumulative genetic risk score (GRS) and to relate specific susceptibility alleles for use of target therapies. The discovery of rare patients with single-gene high-penetrance mutations informed our understanding of pathways driving systemic inflammation. Here, we review the advances in practicing PM in patients with primary systemic vasculitides (PSVs). We summarize recent genetic studies and discuss current knowledge on the contribution of epigenetic factors and extracellular vesicles (EVs) in disease progression and treatment response. Implementation of PM in PSVs is a developing field that will require analysis of a large cohort of patients to validate data from genomics, transcriptomics, metabolomics, proteomics, and epigenomics studies for accurate disease profiling. This multi-omics approach to study disease pathogeneses should ultimately provide a powerful tool for stratification of patients to receive tailored optimal therapies and for monitoring their disease activity.

[Physiopathology of giant cell arteritis: From inflammation to vascular remodeling]

Giant cell arteritis (GCA) is a large-vessel vasculitis involving the aorta and its main branches, especially supra aortic branches. Although much progress has been made, the pathophysiology remains incompletely understood. An initial trigger, suspected of infectious origin, lead to the maturation and recruitment of dendritic cells (DC). The lack of migration of these DC allows the local recruitment of T-lymphocytes (LT). These LT- CD4⁺ polarize in Type 1 helper (Th1), Th17 but also Th9. A qualitative and quantitative deficit in regulatory T cells (Treg) is observed under the influence of IL-21 overproduction. In addition, an imbalance in the Th17/Treg balance is favored by IL-6. The secretion of IFN-γ, IL-17, IL-6, IL-33 is responsible for a sustained local inflammatory reaction that is organized around tertiary lymphoid follicles. Locally recruited macrophages secrete reactive forms of oxygen together with VEGF and PDGF. These growth factors, together with neurotrophins and endothelin contribute to increase the proliferation of vascular smooth muscle cells (VSMCs). The imbalance between matrix metalloproteases (MMP)-2, MMP-9 and MMP-14 and tissue inhibitors of metalloproteases (TIMP)-1 and TIMP-2 also contribute to the remodeling process occurring in the vessel wall. Finally, arterial neovascularization contribute to the perpetuation of lymphocyte recruitment. This persistent remodeling is sometimes complicated by ischemic events responsible for the initial severity of the disease.

Association between histopathological changes and expression of selected microRNAs in skin of adult patients with IgA vasculitis

AIMS

IgA vasculitis (IgAV) is a common small-vessel systemic vasculitisthat is histologically characterised by granulocyte infiltration and IgA deposition in vessel walls. Information on microRNA (miRNA) involvement inIgAVis limited. The aim of this study was to analyse the association between histopathological changes and expression profiles of 14 miRNAs in the affected skin of 70 adult patients with IgAV.

METHODS AND RESULTS

miRNA expression analysis was performed by quantitative real-time polymerase chain reaction and evaluation of histopathological changes by light and immunofluorescence microscopy on formalin-fixed paraffin-embedded skin excision samples. In IgAV-affected skin, granulocyte infiltration was significantly associated with vessel fibrinoid necrosis. Of the analysed miRNAs, four showed two-fold increased expression (let-7d, let-7f, miR-21-5p, and miR-203-3p), five showed five-fold increased expression (let-7b, miR-17-5p, miR-155-5p, miR-423-5p, and miR-451a), and threeshowed 15-fold increased expression (let-7a, miR-21-3p, miR-223-3p), as compared with controls (all P < 0.001). miR-146a-5p and miR-148b-3p showed three-fold decreased expression (P = 0.981 and P < 0.001). The expression of miR-223-3p also showed a significant positive association with granulocyte infiltration and fibrinoid necrosis.

CONCLUSIONS

Altered miRNA expression, especially of miRNA-223-3p, may be associated with the skin inflammatory state in IgAV. The majority of aberrantly expressed miRNAs in IgAV-affected skin are known to influence the nuclear factor-κB signalling pathway, which is crucial for activation of key proinflammatory genes, including those encoding tumour necrosis factor-α, interleukin (IL)-6, and IL-8. Furthermore, miR-146a-5p and miR-148b-3p, which are negative regulators of inflammatory gene expression, showed decreased expression and could contribute to the exaggerated inflammation. Further investigation of miRNA expression in the affected tissues could improve our knowledge of IgAV pathogenesis, and possibly help to identify novel biomarkers in body fluids.

64Cu and fluorescein labeled anti-miRNA peptide nucleic acids for the detection of miRNA expression in living cells

MiRNAs are single stranded RNAs of 18-22 nucleotides. They are promising diagnostic and prognostic markers for several pathologies including tumors, neurodegenerative, cardiovascular and autoimmune diseases. In the present work the development and characterization of anti-miRNA radiolabeled probes based on peptide nucleic acids (PNAs) for potential non-invasive molecular imaging in vivo of giant cell arteritis are described. MiR-146a and miR-146b-5p were selected as targets because they have been found up-regulated in this disease. Anti-miR and scramble PNAs were synthesized and linked to carboxyfluorescein or DOTA. DOTA-anti-miR PNAs were then labelled with copper-64 (64Cu) to function as non-invasive molecular imaging tools. The affinity of the probes for the targets was assessed in vitro by circular dichroism and melting temperature. Differential uptake of fluorescein and 64Cu labeled anti-miRNA probes was tested on BCPAP and A549 cell lines, expressing different levels of miR-146a and -146b-5p. The experiments showed that the anti-miR-146a PNAs were more effective than the anti-miR-146b-5p PNAs. Anti-miR-146a PNAs could bind both miR-146a and miR-146b-5p. The uptake of fluorescein and 64Cu labeled anti-miR-146a PNAs was higher than that of the negative control scramble PNAs in miRNA expressing cells in vitro. 64Cu-anti-miR-146a PNAs might be further investigated for non-invasive PET imaging of miR-146 overexpressing diseases.

Gene and miRNA expression in giant cell arteritis-a concise systematic review of significantly modified studies

Giant cell arteritis (GCA) is a systemic vasculitis in individuals older than 50 years, characterized by headaches, visual disturbances, painful scalp, jaw claudication, impairment of limb arteries, and systemic inflammation, among other symptoms. GCA diagnosis is confirmed by a positive temporal artery biopsy (TAB) or by imaging modalities. A prominent acute phase response with inflammation is the hallmark of the disease, predominantly targeting large- and medium-sized arteries leading to stenosis or occlusion of arterial lumen. To date, there are no reliable tissue markers specific for GCA. Scarce reports have indicated the importance of epigenetics in GCA. The current systematic review reports significantly changed candidate biomarkers in TABs of GCA patients compared to non-GCA patients using qPCR.

The therapeutic potential of tuftsin-phosphorylcholine in giant cell arteritis

Tuftsin-PhosphorylCholine (TPC) is a novel bi-specific molecule which links tuftsin and phosphorylcholine. TPC has shown immunomodulatory activities in experimental mouse models of autoimmune diseases. We studied herein the effects of TPC ex vivo on both peripheral blood mononuclear cells (PBMCs) and temporal artery biopsies (TABs) obtained from patients with giant cell arteritis (GCA) and age-matched disease controls. GCA is an immune-mediated disease affecting large vessels. Levels of 18 cytokines in supernatants, PBMC viability, T helper (Th) cell differentiation of PBMCs and gene expression in TABs were analyzed. Treatment ex vivo with TPC decreased the production of IL-1β, IL-2, IL-5, IL-6, IL-9, IL-12(p70), IL-13, IL-17A, IL-18, IL-21, IL-22, IL-23, IFNγ, TNFα, GM-CSF by CD3/CD28 activated PBMCs whereas it negligibly affected cell viability. It reduced Th1 and Th17 differentiation while did not impact Th22 differentiation in PBMCs stimulated by phorbol 12-myristate 13-acetate plus ionomycin. In inflamed TABs, treatment with TPC down-regulated the production of IL-1β, IL-6, IL-13, IL-17A and CD68 gene expression. The effects of TPC were comparable to the effects of dexamethasone, included as the standard of care, with the exception of a greater reduction of IL-2, IL-18, IFNγ in CD3/CD28 activated PBMCs and CD68 gene in inflamed TABs. In conclusion our results warrant further investigations regarding TPC as an immunotherapeutic agent in GCA and potentially other autoimmune and inflammatory diseases.

Pathogenesis of giant-cell arteritis: how targeted therapies are influencing our understanding of the mechanisms involved

GCA is a chronic granulomatous vasculitis that affects large- and medium-sized vessels. Both the innate and the adaptive immune system are thought to play an important role in the initial events of the pathogenesis of GCA. Amplification cascades are involved in the subsequent development and progression of the disease, resulting in vascular inflammation, remodelling and occlusion. The development of large-vessel vasculitis in genetically modified mice has provided some evidence regarding potential mechanisms that lead to vascular inflammation. However, the participation of specific mechanistic pathways in GCA has not been fully established because of the paucity and limitations of functional models. Treatment of GCA is evolving, and novel therapies are being incorporated into the GCA treatment landscape. In addition, to improve the management of GCA, targeted therapies are providing functional proof of concept of the relevance of particular pathogenic mechanisms in the development of GCA and in sustaining vascular inflammation.

An update on the role of epigenetics in systemic vasculitis

PURPOSE OF REVIEW

The purpose of this review is to discuss recent observations of epigenetic changes related to the complex pathogenesis of systemic vasculitides and their contribution to the field.

RECENT FINDINGS

There have been new observations of epigenetic changes in vasculitis and their potential role in disease pathogenesis in antineutrophil cytoplasmic antibody-associated vasculitis, giant-cell arteritis, Kawasaki disease, Behçet's disease, and IgA vasculitis. Some of this recent work has focused on the efficacy of using DNA methylation and miRNA expression as clinical biomarkers for disease activity and how DNA methylation and histone modifications interact to regulate disease-related gene expression.

SUMMARY

DNA methylation, histone modification, and miRNA expression changes are all fruitful ground for biomarker discovery and therapeutic targets in vasculitis. Current knowledge has provided targeted and suggested effects, but in many cases, has relied upon small cohorts, cosmopolitan cell populations, and limited knowledge of functional interactions. Expanding our knowledge of how these epigenetic mechanisms interact in a disease-specific and cell-specific manner will help to better understand the pathogenesis of systemic vasculitis.

Plasma Circulating Extracellular RNAs in Left Ventricular Remodeling Post-Myocardial Infarction

Despite substantial declines in mortality following myocardial infarction (MI), subsequent left ventricular remodeling (LVRm) remains a significant long-term complication. Extracellular small non-coding RNAs (exRNAs) have been associated with cardiac inflammation and fibrosis and we hypothesized that they are associated with post-MI LVRm phenotypes. RNA sequencing of exRNAs was performed on plasma samples from patients with "beneficial" (decrease LVESVI ≥ 20%, n = 11) and "adverse" (increase LVESVI ≥ 15%, n = 11) LVRm. Selected differentially expressed exRNAs were validated by RT-qPCR (n = 331) and analyzed for their association with LVRm determined by cardiac MRI. Principal components of exRNAs were associated with LVRm phenotypes post-MI; specifically, LV mass, LV ejection fraction, LV end systolic volume index, and fibrosis. We then investigated the temporal regulation and cellular origin of exRNAs in murine and cell models and found that: 1) plasma and tissue miRNA expression was temporally regulated; 2) the majority of the miRNAs were increased acutely in tissue and at sub-acute or chronic time-points in plasma; 3) miRNA expression was cell-specific; and 4) cardiomyocytes release a subset of the identified miRNAs packaged in exosomes into culture media in response to hypoxia/reoxygenation. In conclusion, we find that plasma exRNAs are temporally regulated and are associated with measures of post-MI LVRm.

Higher expression of miR-133b is associated with better efficacy of erlotinib as the second or third line in non-small cell lung cancer patients

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (gefitinib, erlotinib and afatinib) are indicated as first-line therapy in patients with non-small cell lung cancer (NSCLC) whose tumors harbor activating mutations in the EGFR gene. Erlotinib is also used in second and third-line therapy for patients whose tumors have wild type EGFR but to date there are no validated biomarkers useful to identify which patients may benefit from this treatment. The expression level of four miRNAs: miR-133b, -146a, -7 and -21 which target EGFR was investigated by real-time PCR in tumor specimens from NSCLC patients treated with erlotinib administered as the second or third line. We found that miR-133b expression level better discriminated responder from non-responder patients to erlotinib. Higher levels of miR-133b in NSCLCs were associated with longer progression-free survival time of patients. Functional analyses on miR-133b through transfection of a miR-133b mimic in A549 and H1299 NSCLC cell lines indicated that increasing miR-133b expression level led to a decreased cell growth and altered morphology but did not affect sensitivity to erlotinib. The detection of miR-133b expression levels in tumors help in the identification of NSCLC patients with a better prognosis and who are likely to benefit from second and third-line therapy with erlotinib.

miR-223-3p Inhibits Human Osteosarcoma Metastasis and Progression by Directly Targeting CDH6

Cadherin-6 (CDH6) is aberrantly expressed in cancer and closely associated with tumor progression. However, the functions of CDH6 in human osteosarcoma and the molecular mechanisms underlying CDH6 in osteosarcoma oncogenesis remain poorly understood. In this work, we assessed the role of CDH6 in human osteosarcoma and identified that the expression of CDH6 was closely related with the overall survival and poor prognosis of osteosarcoma patients. MicroRNAs (miRNAs) have been implicated as important epigenetic regulators during the progression of osteosarcoma. Using dual-luciferase reporter assays, we showed that miR-223-3p suppresses CDH6 expression by directly binding to the 3' UTR of CDH6. miR-223-3p overexpression significantly inhibited cell invasion, migration, growth, and proliferation by suppressing the CDH6 expression in vivo and in vitro. Besides, CDH6 overexpression in the miR-223-3p-transfected osteosarcoma cells effectively rescued the inhibition of cell invasion, migration, growth, and proliferation mediated by miR-223-3p. Additionally, Kaplan-Meier analysis suggests that the expression of miR-223-3p predicts favorable clinical outcomes for osteosarcoma patients. Moreover, the expression of miR-223-3p was downregulated in osteosarcoma patients and was negatively associated with the expression of CDH6. Collectively, these data highlight that miR-223-3p/CDH6 axis is an important novel pleiotropic regulator and could early predict the metastatic potential in human osteosarcoma treatments.

Pathogenic mechanism of miR-21 in autoimmune lymphoid hyperplasia syndrome

miR-21 plays an important role in immune responses and inflammatory diseases, but the mechanism of action of miR-21 in autoimmune lymphoid hyperplasia syndrome still remains unclear. The aim of the present study was to assess the mechanism of miR-21 in autoimmune disease, particularly, the autoimmune lymphoid hyperplasia syndrome. The pathology and immunity-related phenotypes of miR-21 transgenic mice, and the lymphocyte subsets were analyzed. The related T cell subsets and germinal center B (GCB) cells generated at the germinal center were detected with flow cytometry. The target genes of miR-21 were evaluated with the luciferase reporter gene method. The homeostatic proliferation of the lymphocytes was detected with the EdU incorporation assay. Inflammatory infiltration occurred to the lung and liver of the transgenic mice at 8 weeks. The frequency of the regulatory helper T cells decreased slightly. Significantly increased double negative T cells were observed in the spleen of the transgenic mice (P<0.05). The immunoglobulins IgG1, IgG2a, IgG2b, and IgG3 in the serum of the transgenic mice aged 8 weeks were significantly higher than those in the wild-type mice aged 8 weeks (P<0.05). The percentages of the GCB cells in the peripheral lymphoid organs such as lymph nodes, mesenteric lymph nodes, PP and spleen in the transgenic mice aged 8–52 weeks increased significantly (P<0.05). The percentage (26.32%) of the newly-formed GCB cells derived from transgenic mice was significantly higher than that (3.87%) of the GCB cells derived from the wild-type mice. miR-21 played a role of negative feedback regulation by inhibiting the NF-κB signal pathway. The highly-expressed miR-21 B cells promoted homeostatic proliferation of the T cells. miR-21 can promote homeostatic proliferation of lymphocytes by inhibiting the NF-κB signal pathway.

Epigenetic Modulation as a Therapeutic Prospect for Treatment of Autoimmune Rheumatic Diseases

Systemic inflammatory rheumatic diseases are considered as autoimmune diseases, meaning that the balance between recognition of pathogens and avoidance of self-attack is impaired and the immune system attacks and destroys its own healthy tissue. Treatment with conventional Disease Modifying Antirheumatic Drugs (DMARDs) and/or Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) is often associated with various adverse reactions due to unspecific and toxic properties of those drugs. Although biologic drugs have largely improved the outcome in many patients, such drugs still pose significant problems and fail to provide a solution to all patients. Therefore, development of more effective treatments and improvements in early diagnosis of rheumatic diseases are badly needed in order to increase patient's functioning and quality of life. The reversible nature of epigenetic mechanisms offers a new class of drugs that modulate the immune system and inflammation. In fact, epigenetic drugs are already in use in some types of cancer or cardiovascular diseases. Therefore, epigenetic-based therapeutics that control autoimmunity and chronic inflammatory process have broad implications for the pathogenesis, diagnosis, and management of rheumatic diseases. This review summarises the latest information about potential therapeutic application of epigenetic modification in targeting immune abnormalities and inflammation of rheumatic diseases.