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

Rashid Giniatullin,Vytautas Kašėta,Tarja Malm,Akvilė Jarmalavičiūtė,Augustas Pivoriūnas,Karolina Kriaučiūnaitė,Justina Pajarskienė,Diana Romenskaja,Virginijus Tunaitis,Ugnė Jonavičė

doi:10.3390/ijms222010970

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.

Highlights

Microglia regulate immune homeostasis in the central nervous system (CNS) by initiating, maintaining, and terminating neuroinflammatory response to all types of injuries [1].Dysregulated microglial response is important for the development and propagation of various neurological disorders, and the targeting of neuroinflammatory microglia has been considered a promising therapeutic approach [2,3]
We demonstrate for the first time that extracellular vesicles (EVs) trigger ATP release and promote migration of human microglia through P2X4 receptor (P2X4R)/MFG-E8-dependent mechanisms
Our findings provide novel insights into the molecular mechanisms through which EVs target human microglia

Summary

Introduction

Microglia regulate immune homeostasis in the central nervous system (CNS) by initiating, maintaining, and terminating neuroinflammatory response to all types of injuries [1]. Dysregulated microglial response is important for the development and propagation of various neurological disorders, and the targeting of neuroinflammatory microglia has been considered a promising therapeutic approach [2,3]. Intranasal delivery of EVs has been shown to suppress neuroinflammation and promote neuroprotection in different experimental models [8,9,10,11,12]. EVs target and accumulate in pathologically affected areas of the brain [6,13]. Administered curcumin-encapsulated exosomes are selectively taken up by microglia and suppress secretion of pro-inflammatory cytokines in LPS-treated mice [9]

Methods

Results

Conclusion