Serum levels of tenascin-C in collagen diseases

An investigation of the relationship between Behçet's disease and tenascin-C

Objectives

The study aimed to investigate serum tenascin-C levels and its relationship with pathogenesis of Behçet's disease (BD) with inflammatory processes.

Patients and methods

This prospective and analytical study included 34 BD patients (19 males, 15 females; mean age: 31.5±8.2 years; range, 18 to 48 years) who met the 2014 International Criteria for Behçet's Disease and had no comorbidities and 37 healthy volunteers (21 females, 16 males; mean age: 29.6±5.3 years; range, 21 to 45 years). Sex, age, age at diagnosis, clinical and laboratory data, medication use, and smoking history of the participants were recorded. Serum tenascin-C levels were measured using a commercially available tenascin-C enzyme-linked immunosorbent assay kit.

Results

There was no significant difference between the groups in terms of age (p=0.262) and sex (p=0.287). Serum tenascin-C levels were significantly lower in the BD group (10,824±7,612 pg/mL) compared to the control group (27,574±14,533 pg/mL, p<0.001). In the receiver operating characteristic analysis performed for the diagnostic value of tenascin-C level in BD, the sensitivity was determined as 79.4% and the specificity as 82.5% (p<0.001). No statistically significant difference was observed in tenascin-C levels in correlation with clinical characteristics, laboratory values, medication use, and smoking in the BD group.

Conclusion

In contrast to other chronic inflammatory diseases, lower levels of tenascin-C were observed in patients with BD than in the healthy individuals, which can be attributed to the absence of prolonged chronic inflammatory course in BD. The fact that tenascin-C levels are high in other rheumatic inflammatory diseases but low in BD may be useful in the differential diagnosis of BD.

Tenascin C in radiation-induced lung damage: Pathological expression and serum level elevation

Radiation‐induced lung damage (RILD) is a critical problem in lung cancer radiotherapy, and it is difficult to predict its severity. Although no biomarkers for RILD have been established, tenascin C (TNC) is an extracellular matrix glycoprotein involved in the remodeling of damaged tissues and has been implicated in inflammation and fibrosis. We report the unique case of a 36‐year‐old man with adenocarcinoma of the lung, Union for International Cancer Control stage IIIB, who was treated with radiotherapy before lung surgery. The surgical specimen showed histopathological expression of TNC in the region where radiation pneumonitis was observed radiographically. Serum TNC levels were elevated after radiotherapy. In this case, TNC is suggested to be implicated in RILD and may be a potential candidate as a biomarker for the onset and severity of the condition.

Tenascin-C in fibrosis in multiple organs: Translational implications

Systemic sclerosis (SSc, scleroderma) is a complex disease with a pathogenic triad of autoimmunity, vasculopathy, and fibrosis involving the skin and multiple internal organs [1]. Because fibrosis accounts for as much as 45% of all deaths worldwide and appears to be increasing in prevalence [2], understanding its pathogenesis and progression is an urgent scientific challenge. Fibroblasts and myofibroblasts are the key effector cells executing physiologic tissue repair on one hand, and pathological fibrogenesis leading to chronic fibrosing conditions on the other. Recent studies identify innate immune signaling via toll-like receptors (TLRs) as a key driver of persistent fibrotic response in SSc. Repeated injury triggers the in-situ generation of "damage-associated molecular patterns" (DAMPs) or danger signals. Sensing of these danger signals by TLR4 on resident cells elicits potent stimulatory effects on fibrotic gene expression and myofibroblast differentiation triggering the self-limited tissue repair response to self-sustained pathological fibrosis characteristic of SSc. Our unbiased survey for DAMPs associated with SSc identified extracellular matrix glycoprotein tenascin-C as one of the most highly up-regulated ECM proteins in SSc skin and lung biopsies [3,4]. Furthermore, tenascin C is responsible for driving sustained fibroblasts activation, thereby progression of fibrosis [3]. This review summarizes recent studies examining the regulation and complex functional role of tenascin C, presenting tenascin-TLR4 axis in pathological fibrosis, and novel anti-fibrotic approaches targeting their signaling.

Emerging Roles of Matricellular Proteins in Systemic Sclerosis

Systemic sclerosis is a rare chronic heterogenous disease that involves inflammation and vasculopathy, and converges in end-stage development of multisystem tissue fibrosis. The loss of tight spatial distribution and temporal expression of proteins in the extracellular matrix (ECM) leads to progressive organ stiffening, which is a hallmark of fibrotic disease. A group of nonstructural matrix proteins, known as matricellular proteins (MCPs) are implicated in dysregulated processes that drive fibrosis such as ECM remodeling and various cellular behaviors. Accordingly, MCPs have been described in the context of fibrosis in sclerosis (SSc) as predictive disease biomarkers and regulators of ECM synthesis, with promising therapeutic potential. In this present review, an informative summary of major MCPs is presented highlighting their clear correlations to SSc- fibrosis.

Clinical significance and prognosis of serum tenascin-C in patients with sepsis

Background

Tenascin-C is a pro-inflammatory glycoprotein with various biological functions. High expression of tenascin-C is found in inflammation, tissue remodeling, and autoimmune diseases. However, its expression and clinical significance in sepsis remain unclear. This study was designed to investigate the relationship between serum tenascin-C levels and disease severity and prognosis in patients with sepsis.

Methods

A total of 167 patients with sepsis admitted to the ICU were enrolled. Lood samples were collected within 24 h of admission. Serum tenascin-C levels were measured by enzyme-linked immunosorbent assay (ELISA). Follow-up was performed to observe 30-day mortality.

Results

Serum tenascin-C levels were significantly elevated in patients with sepsis compared with non-sepsis controls (P < 0.001). Serum tenascin-C levels were higher in nonsurvivors (58 cases) who died within 30 days (34.5%) compared to survivors (109 cases) (P < 0.001). In patients with sepsis, serum tenascin-C levels were significantly positively correlated with SOFA scores (P = 0.011), serum creatinine (P = 0.006), C-reactive protein (CRP) (P = 0.001), interleukin-6 (IL-6) (P < 0.001), and tumor necrosis factor α (TNF-α) (P = 0.026). Logistic multivariate regression models showed that serum tenascin-C levels were independent contributor of 30-day mortality. Kaplan-Meier curves showed that septic patients with high levels of serum tenascin-C (≥56.9 pg/mL) had significantly higher 30-day mortality than those with lower serum tenascin-C (< 56.9 pg/mL) (P < 0.001).

Conclusion

Elevated serum tenascin-C was found in septic patients and associated with severity and poor prognosis.

Expression of tenascin-C in a rat vocal fold injury model and its regulation of fibroblasts

OBJECTIVES/HYPOTHESIS

Tenascin-C (Tnc) is an extracellular matrix (ECM) glycoprotein that plays a vital role in wound healing and fibrotic disease. Tnc is highly upregulated soon after vocal fold injury, but its function in the vocal fold has not yet been defined. In this study, we investigated Tnc expression in a rat vocal fold injury model in vivo and its roles in fibroblasts in vitro.

STUDY DESIGN

In vivo and in vitro.

METHODS

Tnc mRNA and protein expression levels were quantified on days 3, 7, 14, 28, and 56 after vocal fold injury in Sprague-Dawley rats. In vitro, immunocytochemistry, Western blot, and quantitative real-time polymerase chain reaction (qRT-PCR) analyses were performed in primary rat vocal fold fibroblasts following Tnc or transforming growth factor (TGF)-β1 stimulation to investigate the phenotypic effects.

RESULTS

Tnc mRNA and protein expression was upregulated dramatically on days 3 and 7 after injury, and significant differences were observed by qRT-PCR (P < .01). In vitro, Tnc significantly stimulated the migration of primary vocal fold fibroblasts. Following incubation with Tnc for 72 hours, α-smooth muscle actin, collagen I, and fibronectin expression was significantly upregulated (P < .05). TGF-β1 increased Tnc expression in a time-dependent manner, and a mothers against decapentaplegic homolog 3 (SMAD3) inhibitor attenuated this TGF-β1-induced stimulation.

CONCLUSIONS

Tnc was highly upregulated during the early postinjury period in vivo and promoted vocal fold fibroblast migration, transdifferentiation, and ECM protein synthesis in vitro. Tnc was induced by TGF-β1 in a SMAD3-dependent manner. Transient expression of Tnc is likely to promote regeneration, but its potential role in fibrosis requires further study.

LEVEL OF EVIDENCE

NA Laryngoscope, 128:E316-E322, 2018.

Tenascins in fibrotic disorders-from bench to bedside

Although fibrosis is becoming increasingly recognized as a major cause of morbidity and mortality in chronic inflammatory diseases, available treatment strategies are limited. Tenascins constitute a family of matricellular proteins, primarily modulating interactions of cells with other matrix components and growth factors. Data obtained from tenascin C deficient mice show important roles of this molecule in several models of fibrosis. Moreover there is growing evidence that tenascin C has a strong impact on chronic inflammation, myofibroblast differentiation and recruitment. Tenascin C as well as tenascin X has furthermore been shown to affect TGF-β activation and signaling. Taken together these data suggest that these proteins might be important factors in fibrosis development and make them attractive both as biological markers and as targets for therapeutical intervention. So far most clinical research in fibrosis has been focused on tenascin C. This review aims at summarizing our up-to-date knowledge on the involvement of tenascin C in the pathogenesis of fibrotic disorders.

Serum tenascin-C discriminates patients with active SLE from inactive patients and healthy controls and predicts the need to escalate immunosuppressive therapy: a cohort study

INTRODUCTION

The aim of this study was to examine whether circulating levels of the proinflammatory glycoprotein tenascin-C (TNC) are useful as an activity-specific or predictive biomarker in systemic lupus erythematosus (SLE).

METHODS

Serum TNC levels were determined by enzyme-linked immunosorbent assay at inception visit in a prospective cohort of 59 SLE patients, and in 65 healthy controls (HC). SLE patients were followed for a mean of 11 months, disease activity was assessed using the Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2 K) and British Isles Lupus Assessment Group disease activity index (BILAG-2004), clinical and laboratory data were recorded every 3-6 months, and changes in glucocorticoids (GC) and immunosuppressants (IS) were recorded serially. We examined cross-sectionally the relationships between serum concentrations of TNC and SLE status, SLEDAI-2 K scores, strata of disease activity, and levels of conventional biomarkers [anti-double-stranded DNA (dsDNA), anti-nucleosome antibodies, C3 and C4]. We also explored the utility of TNC levels for predicting disease flares, defined as (i) new/increased GC, (ii) new/increased GC or IS, and (iii) increase in SLEDAI by ≥3 or (iv) BILAG A or B flare.

RESULTS

There was no significant difference in the mean levels of TNC between the SLE patients and HC. However, in SLE patients with active disease (SLEDAI ≥6), the TNC levels were significantly higher than in the HC (p = 0.004) or in patients with no/low disease activity (p = 0.004). In SLE patients, TNC levels were significantly associated with positivity of anti-dsDNA (p = 0.03) and anti-nucleosome antibodies (p = 0.008). Flares defined by a need to escalate immunosuppressive therapy were captured more frequently and earlier than flares defined by standard activity indices. Higher baseline levels of serum TNC presented a significantly greater risk of flare (i) [hazard ratio (HR) 1.39, 95% confidence interval (CI) 1.11-1.73] or (ii) (HR 1.25, 95% CI 1.02-1.52) but not of flares (iii) or (iv). The baseline serum TNC level was the single most important independent predictor of flare (i) compared with conventional biomarkers.

CONCLUSIONS

TNC is not disease-specific, but it seems to indicate the activity of SLE and may predict the need to escalate immunosuppressive therapy. TNC levels may thus serve as a useful activity-specific and predictive biomarker in SLE.

Recent progress in studies of miRNA and skin diseases

miRNA is a family of small non-coding RNA that consists of 22 nucleotides on average. miRNA are implicated in various cellular activities such as cell proliferation or migration via the modulation of gene expression, and also are linked to the pathogenesis of human diseases. This paper reviews recent research progress about the contribution of miRNA to the pathogenesis of various skin diseases, and possible application of miRNA as the disease markers in each disease. For example, downregulated miR-424-5p in psoriatic skin causes the overexpression of MEK1 and cyclin E1 in psoriatic keratinocytes, resulting in the keratinocyte overgrowth and hyperproliferation seen in the disease. Although there was no significant difference in the serum miR-424-5p levels between psoriasis patients and healthy controls, serum miR-1266-5p levels were significantly upregulated in psoriasis patients, and showed weak and inverse correlation with disease activity. Furthermore, combination of serum levels of miR-146a-5p and -203a-3p was more reliable to distinguish psoriasis patients and normal subjects, than each miRNA alone. Hair shaft miR-424-5p levels were significantly higher in psoriasis patients than normal subjects, while hair root miR-19a-3p levels in psoriasis patients were inversely correlated with the duration between symptom onset and the first visit to the hospital. Future researches of miRNA will enable the advances of their clinical applications including the clarification of pathogenesis, disease markers and novel treatments.

Revisiting the matricellular concept

The concept of a matricellular protein was first proposed by Paul Bornstein in the mid-1990s to account for the non-lethal phenotypes of mice with inactivated genes encoding thrombospondin-1, tenascin-C, or SPARC. It was also recognized that these extracellular matrix proteins were primarily counter or de-adhesive. This review reappraises the matricellular concept after nearly two decades of continuous investigation. The expanded matricellular family as well as the diverse and often unexpected functions, cellular location, and interacting partners/receptors of matricellular proteins are considered. Development of therapeutic strategies that target matricellular proteins are discussed in the context of pathology and regenerative medicine.