the circular RNA HIPK2 (circHIPK2) functions as an endogenous microRNA-124 (MIR124-2HG) sponge to sequester MIR124-2HG and inhibit its activity, resulting in increased sigma non-opioid intracellular receptor 1 (SIGMAR1/OPRS1) expression.
Circular RNA HIPK2 regulates astrocyte activation via cooperation of autophagy and ER stress by targeting MIR124-2HG.