Proinflammatory Cytokines Significantly Stimulate Extracellular Vesicle Production by Adipose-Derived and Umbilical Cord-Derived Mesenchymal Stem Cells

Abstract

Exosomes as well as other extracellular vesicles (EVs) play an important role in cell–cell communication. Recently, EVs have been used as a platform for cellular therapy for conditions such as degenerative diseases. EVs were demonstrated to stimulate angiogenesis, cell proliferation, and immune modulation. This study aims to determine the factors, particularly proinflammatory factors, can stimulate adipose-derived mesenchymal stem cells (ADSCs) and umbilical cord-derived mesenchymal stem cells (UC-MSCs) to generate exosomes and EVs. ADSCs and UC-MSCs were isolated, proliferated, and characterized from adipose tissue and umbilical cord tissue, respectively, according to previously published protocols. The isolated MSCs were treated in vitro with proinflammatory cytokines (including TNF-alpha and IFN-gamma) for 24, 48, and 96 h at three different concentrations (5, 10, and 20 ng/mL). The number count of generated EVs/exosomes was determined by flow cytometry; additionally, exosomes were assessed for amount of nucleic acids and for morphology (via transmission electron microscopy). The results showed that TNF-alpha and IFN-gamma stimulate MSCs from both umbilical cord and adipose tissue to produce a greater number of exosomes and EVs. However, longer culture with proinflammatory cytokines (>96 h) led to a reduction of EV production compared to shorter times (24 or 48 h). Our observations show that EVs are effective cargos for delivery of information in cell–cell communication and are modulated by proinflammatory cytokines in a dose-dependent manner.