Extracellular vesicles from human mesenchymal stem cells expedite chondrogenesis in 3D human degenerative disc cell cultures

Abstract

Background Extracellular vesicles (EVs) from human mesenchymal stem cells (hMSCs) are known to be mediators of intercellular communication and have been suggested as possible therapeutic agents in many diseases. Their potential use in intervertebral disc (IVD) degeneration associated with low back pain (LBP) is yet to be explored. Since LBP affects more than 85% of the western population resulting in high socioeconomic consequences, there is a demand for exploring new and possibly mini-invasive treatment alternatives. In this study, the effect of hMSC-derived small EVs (sEVs) on degenerated disc cells (DCs) isolated from patients with degenerative discs and chronic LBP was investigated in a 3D in vitro model. Methods hMSCs were isolated from bone marrow aspirate, and EVs were isolated from conditioned media of the hMSCs by differential centrifugation and filtration. 3D pellet cultures of DCs were stimulated with the sEVs at 5 × 1010 vesicles/ml concentration for 28 days and compared to control. The pellets were harvested at days 7, 14, and 28 and evaluated for cell proliferation, viability, ECM production, apoptotic activity, chondrogenesis, and cytokine secretions. Results The findings demonstrated that treatment with sEVs from hMSCs resulted in more than 50% increase in cell proliferation and decrease in cellular apoptosis in degenerated DCs from this patient group. ECM production was also observed as early as in day 7 and was more than three times higher in the sEV-treated DC pellets compared to control cultures. Further, sEV treatment suppressed secretion of MMP-1 in the DCs. Conclusion hMSC-derived sEVs improved cell viability and expedited chondrogenesis in DCs from degenerated IVDs. These findings open up for new tissue regeneration treatment strategies to be developed for degenerative disorders of the spine.

Mesenchymal Stem Cell-Derived Exosomes as a Novel Strategy for the Treatment of Intervertebral Disc Degeneration

“…The up-modulation of TIMP-1 and downmodulation of MMP-1/MMP-3 also indicate a healthier balance between catabolism and anabolism. Similar findings were presented by Hingert et al (2020) When comparing degenerated disc cell pellets treated with MSC-derived exosomes to control cultures, it was observed that ECM synthesis was over three times greater in the treated pellets. MMP-1 secretion in the degenerated disc cells was similarly reduced as a result of the exosome therapy.…”

“…For these biochemical challenges, exosomes produced from MSCs have been shown to have a protective impact on NPCs via the mechanism of increasing the expression of chondrocytes, aggrecan, and collagen II in the extracellular matrix and decreasing matrix disintegration via the mechanism of the down-modulation of matrix-degrading enzymes. Moreover, the effects of MSC-derived exosomes on ECM metabolism in IVD cells without any biochemical challenge have also been investigated ( Lu et al, 2017 ; Hingert et al, 2020 ). One study ( Lu et al, 2017 ) showed that after the intervention of exosomes derived from MSC, the ECM expression in degenerated nucleus pulposus cells increases significantly.…”

Mesenchymal Stem Cell-Derived Exosomes: The New Frontier for the Treatment of Intervertebral Disc Degeneration

“…Exosomes inhibited H 2 O 2 -induced NLRP3 inflammasome activation, drastically reduced the catabolic action of MMP-3, MMP-13, IL-6 and inducible nitric oxide synthase (iNOS), repressed reactive oxygen species (ROS) generation and mitochondrial dysfunction was restored [113]. Hingert et al have reported the potential abilities of MSC-derived EVs in a 3D in vitro model to improve cell viability, proliferation, ECM production, apoptosis, chondrogenesis and cytokine secretion in NPCs harvested from patients with IDD and chronic LBP [114]. Furthermore, an actual challenge is the potential of engineered EVs to lead NPC towards a healthy NP-like phenotype, decrease catabolism and inflammation, and improve GAG accumulation both in vitro and in vivo.…”

Stem Cells and Exosomes: New Therapies for Intervertebral Disc Degeneration

“…The knockdown of RASSF5 is suspected to decrease apoptotic cells. An in vitro study on the efficacy of hBMSC-derived exosomes resulted in more than a 50% increase in cell proliferation and decreases in cellular apoptosis in 3D human degenerative disc cell cultures, and ECM production was observed as early as day 7 [ 125 ]. NP cell-derived exosomes can not only induce the differentiation of MSCs into NP-like cells in vitro, but were also found to promote the migration of MSCs and the downregulation of the Notch1 pathway [ 126 , 127 ].…”