Therapeutic potentials of extracellular vesicles derived from mouse DRG-conditioned media-primed human mesenchymal stem cells
Aiwei Sun1, Li Li2, Tarek Klaylat 2, Gopeekrishnan Unnithan3, Magali Millecamps 4, LauraCurran5, Rahul Gawri 2,4, Lisbet Haglund1,2,4,5,6, Chan Gao2,3,4
1 School of Biomedical Sciences, McGill University, 2 Department of Surgery, McGill University, 3 Department of Medicine, McGill University, 4 Alan Edwards Centre for Research on Pain, McGill University, 5 The Research Institute of the McGill University Health Centre, 6 Shriners Hospital for Children, Montreal, Quebec, Canada
Introduction: Extracellular vehicles (EVs) are important in mediating cellular communication by conveying an array of biomolecules. While mesenchymal stem cells (MSC) are known for their anti-inflammatory function through immunomodulation, MSC-derived EVs have not been assessed for their effect on neuroinflammation of nociceptive neurons and therapeutic potential for pain. This study aims to examine the potential of MSC-derived EVs in reducing nociceptive sensitization at dorsal root ganglion (DRG) following concomitant spinal cord injury (SCI) and musculotendinous injury (MTI).
Methods and Materials: Twelve-week-old C57B/L6 mice were subjected to laminectomy and spinal cord transection at T9/T10, followed by an MTI at the left quadriceps muscle-tendon junction induced by 15-second compression using a surgical clamp and a 2 mm tenotomy. The mice were euthanized on postoperative D6, and the mouse DRG (mDRG) below the level of SCI were collected for in vitro culture to collect the conditioned medium (CM) every 3 days for human MSC (hMSC) priming. hMSC-derived EVs were collected, enriched, and purified using Amicon® Ultra-15 Centrifugal Filter Units and size-exclusion chromatography. Their size, concentration, and structure were assessed through nanoparticle tracking analysis (NTA) and transmission electron microscopy (TEM). Purified EVs were implanted into these SCI+MTI mice. Behavioral tests, including von Frey, acetone, and open field evaluations, will commence on postoperative D21 for a two-week period to assess evoked pain and anxiety. The recipient SCI+MTI mice will be euthanized with mDRG collected for post-mortem evaluation of nociceptive sensitization.
Results: TEM depicted cup-shaped and round structures within EVs. NTA demonstrated a higher prevalence of intermediate microvesicles (151-500 nm) compared to exosomes (70-150 nm) and large microvesicles (501-1000 nm) in both non-injury and SCI+MTI groups.
Furthermore, a decreasing trend in total EV quantity was observed in the SCI+MTI group relative to the non-injury group.
Discussion: Our study underscores the promise of mDRG-CM-primed hMSC-derived EVs in relieving SCI-associated pain. Our findings may contribute foundational knowledge, facilitating the advancement of innovative therapeutic strategies for managing chronic pain in spinal cord injuries.
Acknowledgement: FRQ-S, NASS, MUHC, AOSNA, AO Spine, MRMN