Electroacupuncture pretreatment induces ischemic tolerance by neuronal TREM2-mediated enhancement of autophagic flux.

The mechanism of electroacupuncture (EA) pretreatment-induced neuroprotection remains unclear. In this study, we found that neuronal Triggering receptor expressed on myeloid cells 2 (TREM2) expression was increased and peaked at 48 h and 72 h after ischemia/reperfusion. After specific knockdown of TREM2 in excitatory neurons, neurological function was damaged, and the infarct volume was enlarged. Furthermore, the expression of LC3II/LC3I and Beclin1 was decreased, while the expression of p62 was increased. EA pretreatment enhanced TREM2, LC3II/LC3I and Beclin1 expression while reducing p62 in the ischemic penumbra area. The EA-induced neuroprotective effects and improvements in autophagic flux were abolished by specific knockdown of TREM2 in excitatory neurons. Taken together, our findings provide novel mechanistic insight into EA-induced ischemic tolerance and suggest a promising therapeutic strategy of targeting neuronal TREM2 to treat brain ischemia.