Fig 2: SOST was significantly elevated in the in vivo MI model. (A) Echocardiographic measurements and histochemical staining analyses, including H&E, Masson, and Sirius Red staining, were performed to confirm the successful construction of the MI model (Bar =50 µm). Quantitative analysis of LVEDD, LVESD, LVEF, LVFS, myocyte size and fibrotic area are shown in the right panels. (B) The mRNA expression of SOST in the heart tissues was detected by qRT-PCR. (C) Western blot was used to detect the protein expression of SOST in the heart tissues, with GAPDH as the internal control. (D) ELISA was performed to detect the contents of SOST in the different groups. The data are presented as the mean ± SD (n=3). **P<0.01, model group vs. sham group. SOST, sclerostin; H&E, hematoxylin and eosin; LVEDD, left ventricular end diastolic dimension; LVESD, left ventricular end systolic dimension; LVEF, left ventricular ejection fraction; LVFS, left ventricular fractional shortening; MI, myocardial infarction; GAPDH, glyceraldehyde 3-phosphate dehydrogenase; SD, standard deviation.

Fig 3: The expression of the Wnt pathway marker proteins was affected by SOST. (A) The mRNA expression of the Wnt pathway marker genes, including Wnt1, β-catenin, APC, and GSK3β, was detected by qRT-PCR. (B) Western blot was used to detect the protein expression of Wnt1, β-catenin, APC, and GSK3β. GAPDH was used as the internal control. The data are presented as the mean ± SD (n=3). *P<0.05, SOST-overexpression group vs. control group; **P<0.01, SOST-overexpression group vs. control group; ##P<0.01, sh-SOST group vs. control group. SOST, sclerostin; sh, short hairpin; APC, adenomatous polyposis coli; GSK3β, glycogen synthase kinase 3β; qRT-PCR, quantitative real-time polymerase chain reaction; GAPDH, glyceraldehyde 3-phosphate dehydrogenase; SD, standard deviation.

Fig 4: The expression of Wnt signaling marker proteins was affected by SOST in vivo. (A) The expression of Wnt signaling marker genes was detected by qRT-PCR, including Wnt1, β-catenin, APC, and GSK3β. (B) Western blot was used to detect the protein expression of Wnt1, β-catenin, APC, and GSK3β. GAPDH was used as the internal control. (C) Immunofluorescence assays were performed to detect the expression of the Wnt signaling marker proteins (Bar =50 µm). Immunohistochemical staining: green fluorescence marks the corresponding protein and blue fluorescence marks the nucleus. The data are presented as the mean ± SD. *P<0.05, SOST-overexpression group vs. model group; **P<0.01, SOST-overexpression group vs. model group; ##P<0.01, sh-SOST group vs. model group. SOST, sclerostin; sh, short hairpin; APC, adenomatous polyposis coli; GSK3β, glycogen synthase kinase 3β; GAPDH, glyceraldehyde 3-phosphate dehydrogenase; qRT-PCR, quantitative real-time polymerase chain reaction; SD, standard deviation.

Fig 5: SOST inhibited angiogenesis of CMECs and promoted the proliferation and migration of CFs. (A) The mRNA expression of SOST in cells transfected with the SOST overexpression vector and cells transfected with the sh-SOST vector was detected using qRT-PCR. GAPDH was used as the normalization control. (B) The protein expression of SOST in cells transfected with the SOST overexpression vector and cells transfected with the sh-SOST vector was detected with Western blot. GAPDH was used as the normalization control. (C) The tube formation and number of capillary-like structures in cells overexpressing SOST and cells transfected with the sh-SOST vector. (D) CCK-8 assay to detect the cell viability of CFs when overexpressing or suppressing SOST at 24, 48 and 72 h, respectively. (E) The cell cycle of CFs was detected by flow cytometry in cells overexpressing SOST and cells with suppressed SOST expression. (F) CFs were stained with propidium iodide. The migration ability of CFs was detected using the Transwell assay. The data are presented as mean ± SD. **P<0.01, SOST-overexpression group vs. control group; ##P<0.01, sh-SOST group vs. control group. SOST, sclerostin; sh, short hairpin; CMEC, cardiac microvascular endothelial cell; CF, cardiac fibroblast; qRT-PCR, quantitative real-time polymerase chain reaction; GAPDH, glyceraldehyde 3-phosphate dehydrogenase; CCK-8, cell counting kit 8; SD, standard deviation.