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mTORC1 signaling is essential for neurofibromatosis type I gene modulated osteogenic differentiation of BMSCs
Author(s) -
Li YiQiang,
Li JingChun,
Zhou QingHe,
Liu Yuanzhong,
Chen WeiDong,
Xu HongWen
Publication year - 2019
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.26626
Subject(s) - mtorc1 , transfection , small interfering rna , signal transduction , cellular differentiation , cell growth , microbiology and biotechnology , chemistry , osteoblast , cancer research , cell culture , biology , gene , pi3k/akt/mtor pathway , in vitro , genetics , biochemistry
Neurofibromatosis type I (NF1), which is caused by mutations in the NF1 gene, is a common autosomal dominant genetic disease leading to skeletal abnormalities. Both NF1 gene and mammalian target of rapamycin complex 1 (mTORC1) signaling are associated with the osteogenic differentiation of bone marrow stem cells (BMSCs). In this study, we hypothesized that mTORC1 signaling is involved in NF1 ‐modulated osteoblast differentiation of BMSCs. Human BMSCs were cultured in an osteogenic induction medium. The expression of NF1 was either inhibited or overexpressed by transfecting NF1 with a specific small interfering RNA (siRNA) or pcDNA3.0 plasmid, respectively. In addition, an mTORC1 signaling inhibitor and agonist were used to investigate the effects of mTORC1 on NF1 ‐modulated osteogenic differentiation of BMSCs. The results indicated that inhibiting the expression of NF1 with siRNA significantly decreased the mRNA levels of NF1 , whereas overexpressing the expression of NF1 with pcDNA3.0 plasmid significantly increased the mRNA levels of NF1 at days 3, 7, 14 and 21 after culture. We observed reduced osteogenic differentiation and cell proliferation in the NF1 ‐siRNA group and enhanced osteogenic differentiation and cell proliferation of BMSCs in the NF1 ‐pcDNA3.0 group. The activity of mTORC1 signaling (p‐mTORC1, p‐S6K1, and p‐4EBP1) was significantly upregulated in the NF1 ‐siRNA group and significantly inhibited in the NF1 ‐pcDNA3.0 group, 7 and 14 days after culture. The effects of NF1 ‐siRNA and NF1 ‐ pcDNA3.0 on osteogenic differentiation of BMSCs and cell proliferation were reversed by mTORC1 inhibitor and agonist, respectively. In conclusion, NF1 modulates osteogenic differentiation and cell proliferation of human BMSCs and mTORC1 signaling is essential for this process.