Fig. 1.

The FBG domains of tenascin-C, -R, and -W can induce NF-kB activation and cytokine synthesis, and bind to TLR4. a Tenascin-C, -R, -W, and -X each contain an assembly domain, a variable number of epidermal growth factor (EGF)-like repeats, a variable number of fibronectin type III-like repeats (these can be constitutively expressed (white rectangles) or alternatively spliced (gray rectangles) and a C-terminal fibrinogen-like globe (FBG) domain. The FBG domains exhibit a similar molecular weight, comprising between 229 and 240 amino acids each (FBG-C: 26.1 kDa, amino acids 1974–2201, FBG-R: 27.0 kDa, amino acids 1128–1359, FBG-W: 27.5 kDa, amino acids 1060–1300, FBG-X: 26.1 kDa, amino acids 4013–4243); protein accession numbers: tenascin-C (P24821), tenascin-R (Q92752), tenascin-W (Q9UQP3), tenascin-X (P22105). b THP1 NF-kB cells were stimulated with different concentrations of FBG-C, -R, -W, and -X, or were left unstimulated (−) for 24 h and NF-kB activation measured using QUANTI-Blue. Data are shown as mean ± SEM from three independent experiments. One-way ANOVA vs. non-stimulated, **p < 0.01, ***p < 0.001. c–e Primary human macrophages were stimulated with different concentrations of FBG-C,-R, -W, and -X, or were left unstimulated (−) for 24 h, and TNF (c), IL-6 (d), and IL-8 (e) levels measured by ELISA. Data are shown as mean ± SEM from three independent donors. One-way ANOVA vs. non-stimulated, *p < 0.05, **p < 0.01, ***p < 0.001. f 96-well plates were coated with 1 µg ml⁻¹ of FBG-C, -R, -W, or -X, or PBS, and incubated with increasing doses of TLR4. Curves were fitted in GraphPad Prism using one-binding site hyperbola equation. Data in the graph are shown as mean ± SEM from four independent experiments