FIGURE 8.

A synthetic peptide from the LRR6 region of decorin decreases TGF-β activity in an injured skeletal muscle mouse model. A, tibialis anterior muscles of C57BL10 mice were injured by BaCl₂ injection (36). Tibialis anterior muscles were removed at different times post-injury and protein extracts were separated by SDS-PAGE. Levels of LRP-1, CTGF, and embryonic myosin were determined by Western blot analysis. GAPDH levels are shown as a loading control. B, tibialis anterior muscles of C57BL10 mice were injured as in A. At day 3 post-injury, tibialis anterior muscles were injected with TGF-β1 (20 ng) in the absence or presence of complete synthetic LRR6 peptide (10 μg). Tibialis anterior muscles were removed on day 4 post-injury and protein extracts were separated by SDS-PAGE. Levels of CTGF and fibronectin (FN) were determined by Western blot analysis. GAPDH levels are shown as a loading control. C, quantification of three independent experiments as shown in B. Values correspond to the mean ± S.D. for fold-induction relative to control cells without TGF-β1 and LRR6 (* and #, p < 0.05). D, tibialis anterior muscles of C57BL10 mice were injured as in B. TGF-β1 (20 ng) was injected in the absence or presence of complete synthetic LRR6i peptide (10 μg) or scramble peptide (Scr, 10 μg). Tibialis anterior muscles were removed on day 4 post-injury and protein extracts were separated by SDS-PAGE. Levels of phospho-Smad-2 and total Smad-2 were determined by Western blot analysis.