MGF E peptide pretreatment improves the proliferation and osteogenic differentiation of BMSCs via MEK-ERK1/2 and PI3K-Akt pathway under severe hypoxia

- MGF pretreatment can weaken the negative effects of severe hypoxia on BMSCs.
- MGF E peptide inhibited HIF-1α expression.
- Cell proliferation and differentiation were recovered by MGF pretreatment.
- MEK-ERK1/2 and PI3K-Akt signaling pathway were involved in MGF regulating of BMSCs.

AimsSevere hypoxia always inhibits the cell proliferation, osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs), and hinders bone defect repair. Herein we explored the effects of mechano-growth factor (MGF) E peptide on the proliferation and osteogenic differentiation of BMSCs under severe hypoxia.Materials and methodsCoCl2 was utilized to simulate severe hypoxia. MTS was used to detect cell viability. Cell proliferation was verified through flow cytometry and EdU assay. Osteogenic differentiation of BMSCs and osteoblast-specific genes were detected through alkaline phosphatase (ALP) and Alizarin Red S staining, and quantitative real-time PCR, respectively. Hypoxia-inducible factor 1α (HIF-1α), p-ERK1/2 and p-Akt expression levels were detected through western blotting and immunofluorescence.Key findingsSevere hypoxia induced HIF-1α accumulation and transferring into the nucleus, and reduced cell proliferation and osteogenic differentiation of BMSCs. The expression levels of osteoblast-specific genes were markedly decreased after differentiation culture for 0, 7 or 14 days. Fortunately, MGF E peptide inhibited HIF-1α expression and transferring into the nucleus. Cell proliferation and osteogenic differentiation of BMSCs could be recovered by MGF E peptide pretreatment. MEK-ERK1/2 and PI3K-Akt signaling pathway were confirmed to be involved in MGF E peptide regulating the abovementioned indexes of BMSCs. What's more, short-time treatment with MGF E peptide alone promoted the osteogenic differentiation of BMSCs as well.SignificanceOur study provides new evidence for the role of MGF E peptide in regulating proliferation and osteogenic differentiation of BMSCs under severe hypoxia, which may potentially have therapeutic implication for bone defect repair.

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