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. Author manuscript; available in PMC: 2024 Sep 7.
Published in final edited form as: Cell Stem Cell. 2023 Sep 7;30(9):1179–1198.e7. doi: 10.1016/j.stem.2023.08.004

Figure 2. Lgr5 expression is enriched in the superficial zone of articular cartilage perichondrium, but decreases in aging and osteoarthritis.

Figure 2.

(a) H&E images (top row) of key mouse jaw joint developmental stages. in situ hybridization (middle row) of Lgr5 (black triangles) and Sox9 genes in mice. Lgr5-GFP cells (bottow row, pink triangles) in jaw joint superficial zone of Lgr5EFPcre+/− mice. CB=condylar blastema; DPCs=disc progenitor cells; SJC=superior joint cavity; CC=mandibular condylar cartilage; IJC=inferior joint cavity (black arrow), SZ=superficial zone, PZ=polymorphic zone, PC= perichondrium, CZ=chondrocyte zone, HZ=hypertrophic zone. (b) qRT-PCR of Lgr5 in aging mice. (c) qRT-PCR of Lgr5 in Wildtype and Prg4−/− mouse condyles. Data are mean fold change ± SD normalized to GAPDH. ****p≤0.0001; two-way ANOVA followed by Tukey’s post hoc; n=3 mice. (d) qRT-PCR using human bone marrow stromal cells (hBMSCs), healthy human perichondral cells (hPCCs LGR5High) and osteoarthritic human perichondrial cells (OA-2-4-hPCCs LGR5Low). Data are mean fold change ± SD normalized to GAPDH. *p≤0.05; two-way ANOVA followed by Tukey’s post hoc; n=3 experiments. (e) in situ hybridization of Lgr5 and Pthlh and immunohistochemistry of βgalactosidase (βgal), type II collagen (COL2A1) and osteocalcin (OCN) Wt;Topgal and Prg4−/−;Topgal mouse condyles. CB=condylar blastema, SJC=superior joint cavity, DPCs=disc progenitor cells, cWnt+=canonical WNT activity (white arrows), cWnt− = cWnt inactivity (orange bar), white triangles=Lgr5-expressing cells. (f) Quantification of βgal immunostainings from 2e. Data presented are mean % area ± SD normalized to total area; ***p≤0.001; ****p≤0.0001; Two-way ANOVA followed by Tukey’s post hoc; n=3 mice. ***p≤0.01 (g) qRT-PCR of Wildtype and Prg4−/− condyles. Data are mean fold change in gene expression ± SD normalized to GAPDH. **p≤0.01, ***p≤0.001; two-way ANOVA followed by Tukey’s post hoc; n=3 mice.