Co-culturing nucleus pulposus mesenchymal stem cells with notochordal cell-rich nucleus pulposus explants attenuates tumor necrosis factor-α-induced senescence

Abstract

BackgroundCell therapy for the treatment of intervertebral disc degeneration (IDD) faces serious barriers since tissue-specific adult cells such as nucleus pulposus cells (NPCs) have limited proliferative ability and poor regenerative potential; in addition, it is difficult for exogenous adult stem cells to survive the harsh environment of the degenerated intervertebral disc. Endogenous repair by nucleus pulposus mesenchymal stem cells (NPMSCs) has recently shown promising regenerative potential for the treatment of IDD. Notochordal cells (NCs) and NC-conditioned medium (NCCM) have been proven to possess regenerative ability for the treatment of IDD, but this approach is limited by the isolation and passaging of NCs. Our previous study demonstrated that modified notochordal cell-rich nucleus pulposus (NC-rich NP) has potential for the repair of IDD. However, whether this can protect NPMSCs during IDD has not been evaluated.MethodsIn the current study, tumor necrosis factor (TNF)-α was used to mimic the inflammatory environment of IDD. Human NPMSCs were cocultured with NC-rich NP explants from healthy rabbit lumbar spine with or without TNF-α. Cell proliferation and senescence were analyzed to investigate the effect of NC-rich NP explants on TNF-α-treated NPMSCs. The expression of mRNA encoding proteins related to matrix macromolecules (such as aggrecan, Sox-9, collagen Iα, and collagen IIα), markers related to the nucleus pulposus cell phenotype (including CA12, FOXF1, PAX1, and HIF-1α), and senescence markers (such as p16, p21, and p53), senescence-associated proinflammatory cytokines (IL-6), and extracellular proteases (MMP-13, ADAMTS-5) was assessed. The protein expression of CA12 and collagen II was also evaluated.ResultsAfter a 7-day treatment, the NC-rich NP explant was found to enhance cell proliferation, decrease cellular senescence, promote glycosaminoglycan (GAG), collagen II, and CA12 production, upregulate the expression of extracellular matrix (ECM)-related genes (collagen I, collagen II, SOX9, and ACAN), and enhance the expression of nucleus pulposus cell (NPC) markers (HIF-1α, FOXF1, PAX1, and CA12).ConclusionModified NC-rich NP explants can attenuate TNF-α-induced degeneration and senescence of NPMSCs in vitro. Our findings provide new insights into the therapeutic potential of NC-rich NP for the treatment of IDD.

Resveratrol attenuates inflammation environment-induced nucleus pulposus cell senescence in vitro

“…Some studies have showed that inflammatory cytokines induce cell senescence in some cell types, including endothelial progenitor cells and osteoarthritic osteoblasts [14,15]. Importantly, inflammatory cytokines often induces disc NP cell senescence in previous researches [16–18]. Therefore, we deduce that inflammation response-mediated disc NP cell senescence plays an important role in accelerating disc degeneration.…”

“…Inflammation response and cellular senescence are two classical features during disc degeneration [5–13]. Furthermore, there is a positive relationship between inflammation response and disc cell senescence [16–18]. Therefore, inhibition of inflammation response-induced disc cell senescence may be helpful to retard disc degeneration.…”

Activation of SIRT1 promotes cartilage differentiation and reduces apoptosis of nucleus pulposus mesenchymal stem cells via the MCP1/CCR2 axis in subjects with intervertebral disc degeneration

“…IDD disrupts the distribution and density of the aged bone tissues in vertebrae ( 2 ). Nucleus pulposus (NP) mesenchymal stem cells (MSCs) can promote the regeneration of intervertebral discs due to their endogenous repair function ( 3 ). Furthermore, since a loss of NP cells and the ECM are the primary causes of IDD, and MSC differentiation is conducive to intervertebral disc regeneration, the ability of NPMSCs to form cartilage can help to protect patients with IDD ( 4 ).…”

microRNA-130b downregulation potentiates chondrogenic differentiation of bone marrow mesenchymal stem cells by targeting SOX9

“…Moreover, pcDNA-SOX9 markedly promotes the synthesis of extracellular matrix, inhibits levels of IL-6 and TNFa and apoptosis of chondrocytes. SOX9, like Col II and aggrecan, is a member of extracellular matrix-related genes (38). Inflammatory cytokines maintain the balance between the synthesis and catabolism of extracellular matrix proteins (29).…”