Fig 2: Model of BMP expression gradients in the articular and growth plate cartilage.Our current findings suggest BMP gradients in the articular and growth plate cartilages, with higher BMP signaling on the articular surface and the proliferative zone, and lower BMP signaling in the deep and resting zone. Interestingly, although BMP ligands Bmp2 and 6 were most highly expressed in the HZ, BMP signaling (based on pSmad1/5/8) was higheer in the PZ, perhaps because of high Smad7 expression in HZ. The gene names were placed to indicate regions of high expression.

Fig 3: TGF-β1/Smad signaling pathway activation in isolated cardiac fibroblasts. (A) Immunoblots of TGF-β1, Smad2, phospho (p)-Smad2, Smad3, p-Smad3, Smad7 and GAPDH in isolated cardiac fibroblasts treated with serial concentrations of matrine (0.0, 0.5, 1.0, 1.5, 2.0 and 2.5 mmol/l) and/or HG medium are shown. (B) The bar chart shows the relative expression levels of TGF-β1 (TGF-β1/GAPDH). (C) Bar charts also show the phosphorylation of Smad2 (p-Smad2/Smad2), (D) the phosphorylation of Smad3 (p-Smad3/Smad3), (E) the relative expression level of Smad7 (Smad7/GAPDH), and (F) the relative expression level of collagen I (collagen I/GAPDH). Data shown in B-F represent the mean ± standard deviation. *P<0.05 vs. first column; **P<0.05 vs. third column; ***P<0.05 vs. fourth column; #P<0.05 vs. fifth column. TGF-β1, transforming growth factor-β1.

Fig 4: Collagen deposition and TGF-β1/Smad signaling pathway activation in cardiac tissue. (A) In the left part of the figure, captured images of Sirius Red staining of cardiac tissue harvested from each group (Ctrl, Mat, DbCM and DbCM+Mat) are shown. The bar chart on the right shows the values of the optical densities of Sirius Red in each group (results are presented as the mean ± standard deviation). (B) Immunoblots of TGF-β1, Smad2, phospho (p)-Smad2, Smad3, p-Smad3, Smad7, collagen I and the loading control, GAPDH, are shown. The bar chart on the right shows the relative expression levels of TGF-β1 (TGF-β1/GAPDH), Smad7 (Smad7/GAPDH), phosphorylated Smad2 (phospho-Smad2/Smad2), phosphorylated Smad3 (phospho-Smad3/Smad3) and collagen I (collagen I/GAPDH). *P<0.05 vs. Ctrl; **P<0.05 vs. Mat; ***P<0.05 vs. DbCM. TGF-β1, transforming growth factor-β1. Ctrl, control; Mat, matrine; DbCM, diabetic cardiomyopathy.

Fig 5: Smad7 participates in ES-Cell Regulatory Network. (A) Heatmap showing the similarity of their binding sites among diverse transcription factors and coregulators (accession code GSE11431, GSE125116) as well as Smad7 (current study) in mouse ESCs. Colors in the heatmap show the level of overlap for each pair of samples (red, all binding sites overlapped; orange, overlap expected by chance; blue, mutually exclusive binding). Core transcription factors are boxed in blue. Myc cluster is boxed in green. (B) Transcriptional network of regulatory interactions predicted from ChIP-seq binding assays. Nodes are ChIP-seq-assayed transcription factors (Smad7 (purple node) is from the current study, other factors (blue nodes) are from published datasets: accession code GSE11431, GSE125116). The size of each circle represents the degree of the interaction among different factors. Arrowhead indicates the direction of transcriptional regulation. The transcriptional regulation by Smad7 is highlighted by two different patterns: the red dash line indicates the regulation starting from Smad7 (i.e., Pou5f1, Sox2, and Tfcp2l1), and the blue dot line represents the regulation towards Smad7 (i.e., Pou5f1, Sox2, Tfcp2l1, Stat3, Nanog, Esrrb, Klf4, Smad2, Smad3, Smad4, E2f1, and Zfx).