TGF-β3 and IGF-1 synergy ameliorates nucleus pulposus mesenchymal stem cell differentiation towards the nucleus pulposus cell type through MAPK/ERK signaling

Abstract

This study aimed to investigate the synergy between transforming growth factor beta 3 (TGF-β3) and insulin-like growth factor 1 (IGF-1) on nucleus pulposus-derived mesenchymal stem cells (NP-MSCs) and the underlying mechanism using a serum-free culture system. NP-MSC proliferation and viability were measured using a CCK-8 assay and annexin V-FITC/propidium iodide, respectively. NP-MSCs in micromasses were investigated for differentiation towards nucleus pulposus cells (NPCs). SOX-9, collagen-I, collagen-II, aggrecan and decorin expressions were detected by RT-PCR and immunoblotting. Matrix deposition was assessed by sulfated glycosaminoglycan (sGAG) analysis. Novel chondrogenic and nucleus pulposus (NP) genes were detected to distinguish differentiated cell types. MAPK/ERK and TGF/Smad signaling pathways were also examined. As a result, the synergy between TGF-β3 and IGF-1 enhanced NP-MSC viability, extracellular matrix (ECM) biosynthesis and differentiation towards NPCs, partly through the activation of the MAPK/ERK signaling pathway. Therefore, the synergy between TGF-β3 and IGF-1 ameliorates NP-MSC viability, differentiation and promotes intervertebral disc regeneration.

• Insulin-like growth factor 1 (IGF-1)
• intervertebral disc
• MAPK/ERK signaling pathwaymesenchymal stem cell
• nucleus pulposus
• transforming growth factor beta (TGF-β)

Acknowledgements

We acknowledge Dr Lidong Wu (Zhejiang, China) for his gift of rat articular chondrocytes.

Declaration of interest

The authors declare that they have no competing interests.

This work was supported by the grants from the National Nature Science Foundation of China (No. 81171756, 81401822 and 81472114), Science and Technology Planning Project of Zhejiang Province (2012C13013-4 and 2012C33121) and the Health Foundation of Zhejiang Province (LY13H060001).