Extracellular Vesicles from Human Teeth Stem Cells Trigger ATP Release and Promote Migration of Human Microglia through P2X4 Receptor/MFG-E8-Dependent Mechanisms

Abstract

Extracellular vesicles (EVs) effectively suppress neuroinflammation and induce neuroprotective effects in different disease models. However, the mechanisms by which EVs regulate the neuroinflammatory response of microglia remains largely unexplored. Here, we addressed this issue by testing the action of EVs derived from human exfoliated deciduous teeth stem cells (SHEDs) on immortalized human microglial cells. We found that EVs induced a rapid increase in intracellular Ca2+ and promoted significant ATP release in microglial cells after 20 min of treatment. Boyden chamber assays revealed that EVs promoted microglial migration by 20%. Pharmacological inhibition of different subtypes of purinergic receptors demonstrated that EVs activated microglial migration preferentially through the P2X4 receptor (P2X4R) pathway. Proximity ligation and co-immunoprecipitation assays revealed that EVs promote association between milk fat globule-epidermal growth factor-factor VIII (MFG-E8) and P2X4R proteins. Furthermore, pharmacological inhibition of αVβ3/αVβ5 integrin suppressed EV-induced cell migration and formation of lipid rafts in microglia. These results demonstrate that EVs promote microglial motility through P2X4R/MFG-E8-dependent mechanisms. Our findings provide novel insights into the molecular mechanisms through which EVs target human microglia that may be exploited for the development of new therapeutic strategies targeting disease-associated neuroinflammation.

Extracellular vesicles promote lipid raft formation in human microglia through TLR4, P2X4R, and αVβ3/αVβ5 signaling pathways

“…Purinergic signaling plays a crucial role during ATP-induced chemotaxis and phagocytic activity of microglia (Zabala, Vazquez-Villoldo et al 2018) (Ohsawa, Irino et al 2007, Kobayakawa, Ohkawa et al 2019. We have recently showed that EVs promoted the migration of human microglia through the purinergic receptor P2X4 pathway (Jonavice, Romenskaja et al 2021). The present study demonstrates that P2XR4 signaling is indispensable for the EV-induced lipid raft formation in the microglia.…”

“…We have recently demonstrated the importance of purinergic receptor P2X4R signaling for EV-induced microglial migration (Jonavice, Romenskaja et al 2021). Purinergic receptors are also enriched in the inflammatory lipid rafts (Garcia-Marcos, Dehaye et al 2009).…”

Dental Mesenchymal Stem Cell Secretome: An Intriguing Approach for Neuroprotection and Neuroregeneration

“…EVs also induced a rapid increase in intracellular Ca 2+ and ATP release in microglial cells. EVs were also able to promote microglial motility through P2X4 receptor/milk fat globule-epidermal growth factor-factor VIII (MFG-E8)-dependent mechanisms [ 75 ].…”

Nanobiotechnology: A New Frontier for Brain Disorders

“…The mechanisms by which EVs regulate the neuro-inflammation processes of the microglia remain largely unexplored. Recently, the action of EVs derived from human exfoliated deciduous teeth stem cells (SHEDs) (EVs-SHEDs) on human microglial cells has been investigated [ 16 ]. In particular, EVs-SHEDs encourage a rapid increase in the intracellular Ca2+ level, and promote ATP production and microglial migration.…”

“…In particular, EVs-SHEDs encourage a rapid increase in the intracellular Ca2+ level, and promote ATP production and microglial migration. The results demonstrate that EVs-SHEDs have an immunomodulatory effect and induce microglial motility through P2X4R/MFG-E8-dependent mechanisms [ 16 ].…”