Journal: eLife
Article Title: Compositional editing of extracellular matrices by CRISPR/Cas9 engineering of human mesenchymal stem cell lines
doi: 10.7554/eLife.96941
Figure Lengend Snippet: ( A ) Overview of the human RUNX2 coding sequence comprising eight exons. Guide RNAs (gRNAs) and their corresponding expected protein structure. The gRNA targeting exon 2 (orange) disrupts the DNA binding domain, gRNA targeting exon 5 (violet) disrupts nuclear translocation, gRNAs targeting exon 6 (blue) disrupt the transcriptional activation domain, and gRNAs targeting exon 8 (green) disrupt the nuclear matrix targeting signal and repress the protein function. ( B ) Intracellular flow cytometry for RUNX2 detection in mesenchymal sword of Damocles bone morphogenetic type-2 (MSOD-B) and RUNX2-edited clones. A clear protein reduction could be observed in the 6.1_1 and 6.1_23 clones. ( C ) Western blot analysis of RUNX2 in cultured MSOD-B and RUNX2-edited cells. The genetic editing of RUNX2 is confirmed by the detection of the truncated proteins. Actin is used as a control to normalize the protein content. ( D ) Histological analysis of living and lyophilized in vitro differentiated constructs using Safranin O staining (scale bars=100 µm and 20 µm for magnified areas), indicating the presence of cartilage matrices. ( E ) Quantitative assessment of the total GAG content in corresponding in vitro generated lyophilized tissues. Unpaired t-test, n=10–11 biological replicates **p<0.01. ( F ) Immunofluorescence images of MSOD-B and MSOD-BΔR1 lyophilized tissues. Displayed images consist of 3D-stacks from 80 to 100 µm thick sections, stained for DAPI (blue), Collagen Type II (COL2, yellow), and Collagen Type X (COLX, red). A clear reduction in the COLX signal could be observed in the MSOD-BΔR1 tissues, indicating impaired hypertrophy (scale bars=500 µm). ( G ) Isosurface-based quantification of the COL2 immunofluorescent signal using the IMARIS software. No significant difference between groups confirms the retention of cartilage formation in RUNX2-edited constructs. Unpaired t-test, n=3 biological replicates, n.s.=not significant. ( H ) Isosurface-based quantification of the COLX immunofluorescent signal using the IMARIS software, confirming the disruption of hypertrophy in the MSOD-BΔR1 constructs. Unpaired t-test, n=3, ***p<0.001. ( I ) Alizarin Red staining evidencing a lack of mineralization in the MSOD-BΔR1 culture compared to the MSOD-B. ( J ) Quantitative polymerase chain reaction (PCR) analysis displaying the relative expression levels of osteogenesis-related genes: RUNX2, COL1, and ALPL. The expression is normalized to GAPDH as housekeeping gene. n.d.=not detected. All error bars in the figures indicate either the standard deviation (SD) or the standard error of the mean (SEM); the specific metric used is consistent within each figure. Figure 3—source data 1. annotated western blot analysis of Runt-related transcription factor 2 (RUNX2) editing. Western blot analysis of RUNX2 in cultured mesenchymal sword of Damocles bone morphogenetic type-2 (MSOD-B) (MB) and RUNX2-edited cells (clones 6.1 and 6.23, respectively). The genetic editing of RUNX2 is confirmed by the detection of the truncated proteins. Actin is used as a control to normalize the protein content. Exposure was set at 13.7 s. Figure 3—source data 2. annotated western blot analysis of Runt-related transcription factor 2 (RUNX2) editing. Non-annotated western blot pictures of RUNX2 (left part of the gel) in cultured mesenchymal sword of Damocles bone morphogenetic type-2 (MSOD-B) (line 3) and RUNX2-edited cells (clone 6.1 line 4 and clone 6.23 line 5, respectively). The genetic editing of RUNX2 is confirmed by the detection of the truncated proteins. Actin (right part of the gel) is used as a control to normalize the protein content.
Article Snippet: After blocking/permeabilization, sections were stained with primary antibodies: mouse anti-Collagen II (Invitrogen, MA137493), Anti-Collagen 1 (Abcam, ab138492), VEGF polyclonal antibody (Bioss Antibodies, bs-0279R), rabbit anti-Collagen Type X (ColX) (abbexa, abx101469), Goat anti mouse/rat CD31 (R&D Systems, Cat# 11-0319-42), VEGF at 4°C overnight.
Techniques: Sequencing, Binding Assay, Translocation Assay, Activation Assay, Flow Cytometry, Clone Assay, Western Blot, Cell Culture, Control, In Vitro, Construct, Staining, Generated, Immunofluorescence, Software, Disruption, Real-time Polymerase Chain Reaction, Expressing, Standard Deviation