Transforming growth factor-β (TGF-β) induces the expression of chondrogenesis-related genes through TGF-β receptor II (TGFRII)–AKT–mTOR signaling in primary cultured mouse precartilaginous stem cells

• Published in: Biochemical and biophysical research communications Vol. 450; no. 1; pp. 646 - 651
• Main Authors: Li, Cheng, Wang, Qiong, Wang, Jun-fang
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 18.07.2014
• Subjects: adult stem cells; Adult Stem Cells - cytology; Adult Stem Cells - metabolism; AKT; Animals; Animals, Newborn; antibodies; Cartilage, Articular - cytology; Cartilage, Articular - drug effects; Cartilage, Articular - growth & development; Cell Differentiation - drug effects; Cell Differentiation - physiology; Cells, Cultured; chondrocytes; Chondrocytes - cytology; Chondrocytes - drug effects; Chondrocytes - metabolism; Chondrogenesis; Chondrogenesis - drug effects; Chondrogenesis - physiology; collagen; fibroblast growth factor receptor 3; gene overexpression; genes; messenger RNA; Mice; Mice, Inbred C57BL; mTOR; neonates; Oncogene Protein v-akt - metabolism; phenotype; Precartilaginous stem cells; Protein-Serine-Threonine Kinases - metabolism; Receptors, Transforming Growth Factor beta - metabolism; TGF-β; TOR Serine-Threonine Kinases - metabolism; transforming growth factor beta; Transforming Growth Factor beta - pharmacology; PSCs; mTOR; S6K; TGF-β; Precartilaginous stem cells; AKT; mTORC2; Chondrogenesis; mTORC1; FGFR-3; TGFRII
• ISSN: 0006-291X; 1090-2104; 1090-2104
• DOI: 10.1016/j.bbrc.2014.06.030

•We purified FGFR3-expressing precartilaginous stem cells (PSCs) from neonate mice.•TGF-β increases mRNA expression of chondrogenesis-associated genes in mouse PSCs.•TGF-β activates AKT and mTORC1/2 signaling in the cultured mouse PSCs.•AKT and mTOR activation is required for TGF-β-induced chondrogenesis genes expression. Precartilaginous stem cells (PSCs) are adult stem cells which could initiate chondrocytes and bone growth. In the current study, we purified PSCs from the neonate mice’ perichondrial mesenchyme through immunomagnetic beads with the fibroblast growth factor receptor-3 (FGFR-3) antibody. Mouse PSCs were seeded and cultured, and their phenotype was confirmed by FGFR-3 over-expression. Transforming growth factor-β (TGF-β) was added to induce PSCs differentiation. TGF-β increased mRNA expression of chondrogenesis-related genes (collagen type II, Sox 9, and aggrecan) in the cultured PSCs, which was abolished by TGF-β receptor II (TGFRII) lentiviral shRNA depletion. TGF-β induced AKT activation in mouse PSCs, while the PI3K/AKT inhibitor (LY294002) and the AKT specific inhibitors (perifosine and MK-2206) largely suppressed TGF-β-induced collagen II, Sox 9, and aggrecan mRNA expression. Meanwhile, the mTOR complex 1 (mTORC1) blocker RAD001 or the mTORC1/2 dual inhibitor AZD-2014 also alleviated TGF-β-induced chondrogenesis-associated genes expression. Further, lentiviral shRNA depletion of SIN1 (a mTORC2 component) or mTOR inhibited TGF-β’s effect in the mouse PSCs. In conclusion, our evidence suggests that TGF-β induces the expression of chondrogenesis-related genes through TGFRII–AKT–mTOR signaling in cultured mouse PSCs.