Tenascin‐C is increased in atherothrombotic stroke patients and has an anti‐inflammatory effect in the human carotid artery

Abstract

Tenascin-C (Tn-C) is an endogenous ligand of toll-like receptor-4 (TLR-4); a key signalling molecule associated with chronic inflammatory conditions. Both Tn-C and TLR-4 are increased in unstable human atheroma, but their effects on local inflammatory conditions have not been investigated. The aim of the present study was to investigate the association and functional implications of Tn-C/TLR-4 signalling in large artery atherosclerotic stroke. Plasma Tn-C was measured by ELISA and found to be higher in recent stroke patients (n = 336; median 12.77 µg/mL, inter-quartile range 10.23-15.74 µg/mL) than in controls (n = 321; median 11.31 µg/mL, inter-quartile range 8.89-13.90 µg/mL), P < 0.001. Plasma Tn-C was also independently positively associated with stroke (odds ratio for highest Tn-C quartile 2.27, 95% confidence interval 1.37-3.76). Assessment of Tn-C associated chronic cytokine secretion was performed in vitro using paired, human, macroscopically disease matched, carotid atheroma tissue biopsies obtained from five patients undergoing carotid endarterectomy. A 4-day incubation with specific Tn-C blocking antibodies (Abs) increased secretion of TLR-4-associated cytokines, interleukin (IL)-8, IL-1β, tumour necrosis factor and C-C motif chemokine (CCL)3 and expression of TLR-4 in the tissue. These results suggest with Tn-C blockade another endogenous TLR-4 ligand upregulates TLR-4 expression and subsequent cytokine secretion. Titration of the Tn-C Abs also dose dependently increased secretion of IL-6, IL-8, IL-1β, and CCL3 in mixed, healthy, primary vascular cell culture. In summary, circulating concentrations of Tn-C are higher in patients with a recent history of atherosclerotic stroke and may play an anti-inflammatory role by reducing pro-inflammatory cytokine release from atheroma.

Involvement of Angiotensin II Type 1 and 2 Receptors in Gelatinase Regulation in Human Carotid Atheroma <i>in vitro </i>

“…MMP-2, -3, -9, TIMP-1, -2, -4, ATR1, ATR2, ERK1-P, ERK2-P and ERK1/2 expression and MMP-2 and -9 relative activation and overall catalytic capacity in the paired explant samples are presented as mean SEM for the relative ratios of paired experimental and control samples (n 14 or 12 pairs) 28,[32][33][34][35] . Differences between experimental and control samples were assessed using Wilcoxon's paired test in SPSS v21 software.…”

“…A previously developed mixed, healthy, primary vascular cell technique 32,33) was used to assess the impact of ATR blockade on MMP-9 production from healthy vascular cells stimulated by serum, which would not be expected to have ATR2 expression. Irbesartan (0, 0.144, 0.575, 2.3 and 4.6 mmol/L) and PD123319 (0, 0.063, 0.25, 1 and 2 µM) were titrated in the mixed, healthy, primary vascular cell cultures.…”

“…To minimise the impact of any medications the patient may have been receiving, a 24h preincubation step is included before the intervention study itself. We have previously shown the combination of these techniques minimises the heterogeneity between paired blockade and control samples 28,[32][33][34][35] . We also accept the potential for false discovery when many different outcomes are examined in the same samples.…”

“…The underlying regulatory mechanisms behind the pleomorphic beneficial outcomes of ATR1 blockade in atherosclerosis patients are also yet to be elucidated. In this study we aimed to clarify the roles of ATR1 and ATR2 in gelatinase regulation in carotid atheroma using paired human carotid atheroma explant culture 28,[32][33][34][35] and ATR blockers specific to type 1 or type 2.…”

ATF3 Inhibits Tenascin-C-induced Foam Cell Formation in LPS-Stimulated THP-1 Macrophages by Suppressing TLR-4

“…Specifically, TN-C expression in adult arteries is co-incident with sites of vascular disease, which has been linked to the development and complications of intimal hyperplasia, myocardial infarction, pulmonary artery hypertension, heart failure, cardiac and arterial injuries, and atherosclerosis 9) . TN-C is an endogenous ligand of toll-like receptor-4 (TLR-4), a key signaling molecule associated with chronic inflammatory conditions 10) , and the levels of both molecules increase in unstable human atheroma 10) . Further, TN-C and OX40 ligand (OX40L) have been shown to be involved in the pathogenesis of atherosclerosis 11) .…”