Research Paper Volume 11, Issue 20 pp 9167—9187

Bone marrow-derived mesenchymal stem cells in three-dimensional co-culture attenuate degeneration of nucleus pulposus cells

Xunlin Li 1, *, , Aimin Wu 1, 2, *, , Chen Han 1, , Chen Chen 1, , Tangjun Zhou 1, , Kai Zhang 1, , Xiao Yang 1, , Zhiqian Chen 1, , An Qin 1, , Haijun Tian 1, , Jie Zhao 1, ,

  • 1 Department of Orthopaedics, Ninth People’s Hospital, Shanghai Jiaotong University School of Medicine, Shanghai Key Laboratory of Orthopaedic Implants, Shanghai, P. R. China
  • 2 Department of Spine Surgery, Zhejiang Spine Surgery Centre, Orthopaedic Hospital, The Second Affiliated Hospital and Yuying Children’s Hospital of the Wenzhou Medical University, The Second School of Medicine Wenzhou Medical University, The Key Orthopaedic Laboratory of Zhejiang Province, Wenzhou, P. R. China
* Equal contribution and co-first authors

received: April 14, 2019 ; accepted: October 21, 2019 ; published: October 30, 2019 ;

https://doi.org/10.18632/aging.102390
How to Cite

Copyright © 2019 Li et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Abstract

Intervertebral disc degeneration (IDD) is an irreversible aging-associated clinical condition of unclear etiology. Mesenchymal stem cells (MSCs) have the potential to delay IDD, but the mechanisms by which MSCs attenuate senescence-related degeneration of nucleus pulposus cells (NPCs) remain uncertain. The present study employed a three-dimensional (3D) co-culture system to explore the influence of MSCs on NPC degeneration induced by TNF-α in rat cells. We found that co-culture with bone marrow-derived MSCs (BMSCs) reduced senescence-associated β-galactosidase expression, increased cell proliferation, decreased matrix metalloproteinase 9, increased Coll-IIa production, and reduced TGFβ/NF-κB signaling in senescent NPCs. In addition, expression of zinc metallopeptidase STE24 (ZMPSTE24), whose dysfunction is related to premature cell senescence and aging, was decreased in senescent NPCs but restored upon BMSC co-culture. Accordingly, ZMPSTE24 overexpression in NPCs inhibited the pro-senescence effects of TGFβ/NF-κB activation upon TNF-α stimulation, while both CRISPR/Cas9-mediated silencing and pharmacological ZMPSTE24 inhibition prevented those effects. Ex-vivo experiments on NP explants provided supporting evidence for the protective effect of MSCs against NPC senescence and IDD. Although further molecular studies are necessary, our results suggest that MSCs may attenuate or prevent NP fibrosis and restore the viability and functional status of NPCs through upregulation of ZMPSTE24.

Abbreviations

NP: nucleus pulposus; NPCs: nucleus pulposus cells; MSCs: mesenchymal stem cells; BMSCs: bone marrow-derived mesenchymal stem cells; 2D co-culture: two-dimensional co-culture; 3D co-culture: three-dimensional co-culture; ZMPSTE24: zinc metallopeptidase STE24; CAGBs: Calcium Alginate Gel Balls; IDD: intervertebral disc degeneration; MMP9: matrix metalloproteinase 9; SA-β-gal: senescence-associated β-galactosidase; SASP: senescence-associated secretory phenotype.