Comparative Analysis of Dual‐ miRNA Mediated Stimulation of Nucleus Pulposus and Bone Marrow Derived Stem Cells for Intervertebral Disc Repair

Background Intervertebral disc (IVD) degeneration is the primary cause of low back pain (LBP). Disease progression is characterized by a shift in extracellular matrix homeostasis towards degradation over regeneration, a process that is a key target of emerging therapeutic strategies. Our laboratory has previously identified the dual delivery of FLR‐miRNA‐149‐5p mimic and 221‐3p inhibitor as being beneficial in generating an anti‐catabolic regenerative niche. Cell therapies have likewise demonstrated potential, though the most suitable cell source has been debated. Materials and Methods In this study, we explored the stimulation of nucleus pulposus and bone marrow derived stem cells with our therapeutic miRNA pair, with the aim of identifying the most suitable cell population for delivery to the IVD. Culture systems of increasing complexity ranging from monolayer to ex vivo organ culture were employed using caprine cells and IVD organs due to their physiological relevance to humans. Results We demonstrated the maintenance of our previously reported anti‐catabolic niche, with significant downregulation of matrix degrading factors, ADAMTS5 and MMP13 and pro‐inflammatory cytokines, TNF and IL‐1β. Furthermore, delivery of dual‐miRNA stimulated nucleus pulposus cells in an organ culture model of mild IVD degeneration significantly upregulated the matrix markers, SOX9 and aggrecan. However, this matrix response was not identified in dual‐miRNA‐bone marrow derived stem cells delivered to goat IVD organs. Conclusion Taken together, these findings highlight the potential of nucleus pulposus cells as a regenerative cell source when combined with FLR‐miRNA‐149‐5p mimic and 221‐3p inhibitor for the treatment of LBP.