Abstract Regulatory T cells (Tregs) are found to participate in the pathogenesis of cerebral ischemic stroke. Exosomes derived from Tregs (Treg-Exos) were found to mediate the mechanism of Tregs’ roles under various physiological and pathological conditions. But the roles of Treg-Exos in cerebral ischemic stroke are still unclear. Here, we explored the protective effects of Treg-Exos against microglial injury in response to oxygen-glucose deprivation/reperfusion (OGD/R) exposure. The results showed that Tregs-Exos relieved OGD/R-caused increases in LDH release and caspase-3 activity in BV-2 cells. The decreased cell viability and increased percentage of TUNEL-positive cells in OGD/R-exposed BV-2 cells were attenuated by Tregs-Exos treatment. Tregs-Exos also suppressed OGD/R-induced increase in production of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 in BV-2 microglia. Furthermore, Tregs-Exos induced the expression levels of phosphorylated phosphatidylinositol-3-kinase (p-PI3K) and phosphorylated protein kinase B (p-Akt) in BV-2 microglia under the challenge of OGD/R. Inhibition of the PI3K/Akt signaling by LY294002 partly reversed the effects of Tregs-Exos on cell apoptosis and inflammation in OGD/R-exposed BV-2 microglia. These results indicated that Tregs-Exos exerted protective effects against the OGD/R-caused injury of BV-2 microglia by activating the PI3K/Akt signaling.

A novel electrochemiluminescence (ECL) biosensor for highly sensitive and selective detection of Ag+ is developed based on the sensitive “turn-on” structure-switching trigeminal structure of deoxyribonucleic acid (DNA-TS). DNA-TS consists of three oligonucleotides hybridized to form three double-stranded DNA like Y-shaped DNA structure. The formation of DNA-TS makes the ECL sign Ru(bpy)2(mcbpy-O-Su-ester)(PF6)2 of reporter probe approach to the electrode surface and thus increase the ECL signal intensity. The “signal-on” ECL biosensor could detect Ag+ concentration in the range from 1.0 × 10-11 to 3.2 × 10-9 mol L-1, and the limit of detection is 3.0 × 10-12 mol L-1. The strategy is sensitive and rapid. This approach could be extended to the design of sensors for other desired heavy metal ions as well. Such ECL sensors are promising for sensitive detection of other heavy metal ions.